An AAA is a pathological focal dilatation of the abdominal stem artery. The AAA bears the risk of rupture. The rupture of the aneurysm is a traumatic emergency condition with a high risk of death. Immediate emergency surgery may reduce the risk of death (peri-operative mortality for emergency repair was described as between 40% and 60% {5}) but is often not available because of uncertainty about the time of rupture. The risk of rupture increases with the diameter of the dilatation {4}. The cut-off point for preventive surgery is 5.5 cm {27}. Elective repair is indicated for AAAs with a diameter of 4.0 to 5.4 cm {18}. A screening programme is indicated to identify AAA with a high risk of rupture. Identified individuals are offered preventive surgery to reduce their individual risk of the negative consequences of a spontaneous rupture.

In the ICD (International Classification of Diseases) 10 two branches are designed for AAA. Branch I71.3 “Abdominal aortic aneurysm, ruptured” defines a ruptured aneurysm, and branch I71.4 “Abdominal aortic aneurysm, without mention of rupture” defines the condition of AAA without rupture {8}.

The National Library of Medicine (where the medical literature catalogue PubMed is also located) defines the MeSH (medical subject headings) term used for AAA as “An abnormal balloon- or sac-like dilatation in the wall of the abdominal aorta which gives rise to the visceral, the parietal, and the terminal (iliac) branches below the aortic hiatus at the diaphragm” The definition was introduced in the year 1993 {9}.

There are several other definitions of AAA in the literature including "An aneurysm is a focal dilation of a blood vessel with respect to the original or adjacent artery. An abdominal aortic aneurysm is defined as an aortic diameter at least one and one-half times the diameter measured at the level of the renal arteries. The normal diameter of the abdominal aorta is approximately 2.0 cm (range 1.4 to 3.0 cm) in most individuals; a diameter greater than 3.0 cm is considered aneurysmal". {1}

A more pathophysiological definition of AAA is given by {3}: “the progressive loss in the capacity to resist high intraluminal pressure, related to the degradation of the arterial wall”.

Clarification: What is the current rate of screening adherence?

Age and sex are risk factors for AAA. The prevalence of AAAs increases with age. While they are uncommon in people below the age of 60 years, 1 person per 1000 develops an AAA in the 60-65 age group {4}. AAAs are four times more common in men than in women {4}. The following additional risk factors are discussed below:

• smoking
• cardiovascular disease
• family history of AAA
• hypertension (mentioned in some sources only —{HTA core model questionnaire})

In its natural course, an AAA is typically symptom free to begin with. The arterial dilatation takes place gradually over the years and is diagnosed as AAA when the arterial diameter reaches 3 cm (Different definitions are used for men and women because the vessels of women are on average smaller than those of men.). Over time the diameter usually increases at a rate that depends on the diameter. In small aneurysms it increases by about 2 mm per year, but in large aneurysms it grows by about 3.5 mm per year. In smokers the rate of increase can be higher. The rate of growth can vary, with phases of no growth and phases of rapid growth{Mohler, Natural ...}. AAAs can be symptomless during the whole life or until rupture. Alternatively symptoms may be present (see A0005).

The pathogenic roles of an inflammatory process (matrix metalloproteinase) and pathological coagulation (plasmin generation) have recently been described {3}. These processes damage the vessel wall, which becomes more vulnerable to the pulsating blood pressure leading to increased dilatation and finally to rupture.

Of the patients with a ruptured AAA, 50% reach hospital alive. Among those who reach hospital alive and have an operation, 50% survive the repair.

See CUR4

Unruptured AAAs are not usually symptomatic. However, symptoms of back pain or abdominal pain, or symptoms due to embolism to the leg can be present. During general clinical examination a pulsatlile abdominal mass may be present {4}. Hypotension may also be present. Other symptoms that are described in the literature may be symptoms from mass effects to adjacent structures (e.g. compression of the ureter or occlusion of a vertebral artery branch) {12}.

The risk of rupture is mainly associated with the diameter of the AAA. The annual risk according to the diameter has been described as follows {4}

Less than 4.0 cm in diameter = less than 0.5% chance of rupture

Between 4.0 to 4.9 cm in diameter = 0.5 to 5% chance of rupture

Between 5.0 to 5.9 cm in diameter = 3 to 15% chance of rupture

Between 6.0 to 6.9 cm in diameter = 10 to 20% chance of rupture

Between 7.0 to 7.9 cm in diameter = 20 to 40% chance of rupture

Greater than or equal to8.0 cm in diameter = 30 to 50% chance of rupture

The burden of AAA arises from the risk of AAA rupture and from harm that may arise from preventive actions against the risk of rupture. From a public health perspective the benefits and harms from organised preventive actions (and their consequences) must be compared with the benefits and harms from care that is not organised in the form of a public health programme (individual care, opportunistic screening).

The benefit and harm that may be introduced by a screening programme depend on the prevalence of the disease (prevalence of AAAs, ruptured AAAs and deaths from ruptured AAAs), and on the effectiveness of the screening and of the preventive interventions. Information about AAA prevalence is given in this result card, whereas information about screening programme characteristics (sensitivity, specificity) is given in the Description and technical characteristics of the technology (TEC) domain and information about the effectiveness of preventive interventions (e.g. surgery, behavioural change) is in the Effectiveness of the technology (EFF) domain.

The public health burden of AAA is increasing in developed countries because of its increasing prevalence in many populations {10}. This increase in prevalence can be explained, in part, by the increase in the number of people in the age groups at higher risk of developing AAA. In European countries {Table} the number of people aged 60-79 has increased from 14% in 1990 to 17% in 2010.

Mortality in different age groups

The mortality due to ruptured AAAs varies in different age groups as follows {5}:

Prevalence in high risk groups

The following table shows AAA prevalence in high risk age groups among five British populations (with definitions of AAA by diameter around 3 cm):

Overall, the prevalence of AAA in these ‘high risk’ age groups is around 4%-8 %.{5}

Incidence is poorly defined (and the usual approach is to use cases that have already been incident), these figures may only give a broad and vague picture.

Ruptured AAAs have a high risk of death (see CUR6). If the patient survives the emergency surgery, they still have a higher mortality risk.

By entering the screening programme the following clinical and economic outcomes may change:

• mortality (overall/disease specific)
• life expectancy
• progression to ruptured AAA
• complications of surgery including distal embolus, haemorrhage and graft failure, coronary and cerebrovascular events and renal complications
• subjective measures including quality of life scores and ability to work
• use of resources including hospital stay and use of intensive care facilities

{19}

In many organised screening programmes the target population (those who are invited) is around 65-80 years and males. In some screening programmes additional risk factors must be present to be included to screening.

In European countries the percentage of men in the high risk age group varies across countries and has tended to increase over the last 20 years. In 2010 Germany and France had the highest percentage (20%) of men aged 60-79. The lowest percentages reported were in Iceland and Ireland (13%). The average percentage of men aged 60-79 (among all men) has risen in 31 European countries* from 14% in 1990 to 17% in 2010. With the exception of Norway (1990:16%, 2010:16%), all the countries show trends towards an increasing percentage in this age group.

In 31 European countries there are ~43 millions of men aged 60-79.

A nationwide population-based screening programme is performed only in the UK ({3} citing {20}).

The EUnetHTA survey reported that Sweden also invites men for AAA screening.

In many countries possible implementation of a screening programme is being discussed.

The highest attendance rates can be expected from decentralised screening {21}, followed by hospital based screening {21}. The lowest rates are likely for general practice based screening {5}.

The VIBORG study {21} presents attendance rates for a hospital based mass screening for AAA showing the effect of various factors:

It has also been reported that while hospital based screening has an attendance rate of around 80%, the uptake in a general practice based screening is likely to be between 50% and 70% {5}

Population-based screening programmes may be implemented nationwide or regionally. The AAA screening described in the literature is either hospital based screening or general practice based screening, for which different attendance rates are described. No statements about the quality of the screening programme (patient information, safety, characteristics of the screening instrument and the preventive intervention   strategy) could be identified in the literature on the types of screening.

In the literature, variations in attendance rates in different screening programmes were the only variations identified. (see CUR23)

Screening programmes vary in the intended target groups, in the location of screening and the number of screenings during a lifetime.

In the UK National Health Service (NHS) AAA screening programme men who turn 65 are automatically invited to the programme. Men who are older and have not been screened previously can opt in through self-referral {UKNSP2010#Health...}.

No information was identified, about how different screening programmes vary in the preventive strategies used (e.g. surgery, behavioural change).

In the survey questions about “other technical devices beside the gold standard” five countries listed the following techniques:

• Denmark: computed tomography (CT) scan
• Lithuania: Ultrasound  and computed tomography, magnetic resonance tomography
• Latvia: MR angiography
• Sweden: If ultrasound does not provide adequate images, CT is performed. This is very infrequent
• Croatia: There is no AAA screening programme in Croatia. But, for example, digital subtraction angiography (DSA) could serve as a diagnostic technology. MR could also serve for diagnosis, because AAA could be an incidental finding during examination for other abdominal illness or during colour-Doppler examination of peripheral arteries.

There are several guidelines giving recommendations on AAA screening.

These recommendations vary in the age groups for whom screening is recommended, in the question of whether women should generally be included or not, and in whether inclusion should be limited by individual risk factors such as smoking.

The results from the EUnetHTA survey list open surgery and endovascular surgery for treating high risk AAAs as follows:

• Austria: open surgery with aortic grafts or abdominal stent
• Croatia: open surgery or EVAR
• Finland: open or endovascular surgery
• Latvia: open surgery (common) or endovascular surgery (for patients participating in clinical trial)
• Lithuania: open or endovascular surgery
• Slovakia: open surgery or stent graft
• Spain: open surgery or EVAR
• Sweden: open or endovascular surgery

Intervention depends on the diameter of the AAA. For smaller aneurysms (3.0 –3.9 cm) with a lower risk of rupture, medical therapy and watchful waiting is recommended (see CUR14). For medium sized aneurysm (4.0 – 5.4 cm) elective surgery is indicated (see CUR14). AAAs that are 5.5 cm or more in diameter the cut-off point of repair is reached {27}. Whether to use endovascular or an open surgical approach should be decided on an individual base. Open surgery is indicated for patients with a low preoperative risk (younger patients). Endovascular surgery is indicated in patients with favourable anatomy and who are at high surgical risk {Baum#Endovascular repair}.

Alternatives to screening based on research (a study design with a control group) could not be identified.

This question seems not to be applicable for AAA screening.

To be identified.

Background information on screening as an intervention

The following table gives an overview of differences between screening practices. Details are described below.

Table 1: Overview and separation of screening strategies

History of Screening

The first routine investigations in healthy people were done around 1860 concurrently in the UK and the USA. At that time the main purpose was to gain new scientific insights into diseases and their prevention. Routine investigations were rapidly accepted in the USA because of the endorsement of insurance companies, who wanted to minimise the health risk profiles of their members, employers who wanted to ensure a healthy workforce and increase productivity, and because of medical scientists, who wanted to continue their pioneering task even if neither the health-related, nor the financial benefit of such routine investigations was clear at the beginning. In Europe, the need for quality assured and informed screening programmes has become more accepted since 1960. Current and future challenges to screening involve the weakened traditional authority of medical science, the changing risk awareness of the population, the advancement of genetic research, the decentralisation of healthcare and the growing financial burden of healthcare costs. {1}

Definition of Screening

The definition of screening and what people really mean when they use the term screening varies widely between professional groups and with time and local conditions. The primary objective of medical screening is to identify a disease or condition in its preclinical and therefore potentially curable stage in apparently healthy people or people believing themselves to be healthy.

For identification of a disease or condition, individual screening tests or a quality assured and evidence based screening programme, which includes all relevant interventions to reduce risk, can be applied. Additionally, every person in the entire population, or a target subgroup of the population with a high prevalence of risk factors for a certain disease or condition, can be included for screening. Furthermore, screening can be implemented in the inpatient or outpatient sector and executed by different experts. On the basis of the screening results people may be offered information, further assessments and/or appropriate therapy. {2, 3}

Screening does not apply to investigations, performed at a time when signs and symptoms of a disease have already occurred. However, there are some tests and investigations, which are carried out in healthy people and fulfil some criteria of screening programmes, but are not defined as having screening as their primary intention, for example occupational investigations at a workplace, preliminary investigations before operation, epidemiological surveys, lifestyle and fitness assessments or investigations for secondary disease. {1}

Requirements for screening

Before starting to plan and implement screening practices for a condition or disease, it is important to check if the criteria for viability, effectiveness and appropriateness are fulfilled. In 1968, the World Health Organization published principles and practices of screening for disease and listed some basic criteria that should ideally be fulfilled: {4}

1. The condition or disease should be an important health problem.
2. An accepted and effective treatment should be available.
3. Facilities for diagnosis and treatment should be available.
4. The condition or disease should have a recognisable latent or early symptomatic stage.
5. There should be a suitable test or examination.
6. The test should be acceptable to the population.
7. The natural history of the condition, including development from latent to declared disease, should be adequately understood.
8. There should be an agreed policy on whom to treat as patients.
9. The screening cost should be economically balanced in relation to total medical expenditures.
10. Case-finding should be a continuing process and not a "once and for all" project.

Additionally, detailed criteria, developed by the UK National Screening Committee, are available online http://www.screening.nhs.uk/criteria. {2}

Implementation of a screening programme

How a screening programme should be or is implemented depends on healthcare systems, strategies, medical services offered and financing of the screening programme. Essential elements that influence improvements in the health of a population as a result of implementing a screening programme are listed below. {1, 5}

• Coordination and project management of the screening strategy.
• Setting up objectives (in general and in detail) and policy.
• System development and information management.
• Constituting operative methods.
• Quality assurance.
• Analysis and assessment of evidence; assigning new research.
• Screening equipment (equipment needed; equipment default set up; safety, compliance and quality assurance on machines; equipment review and replacement; transport of equipment; storage; consumables and other items needed; cleaning; packing up instructions).
• Accommodation requirements (clinic rooms, screening office, etc.).
• Organisation of public relations (leaflets, website, poster, etc.).
• Identification of relevant people.
• Invitation of relevant people.
• Information and consultation of participants.
• Staff requirements (for example: project management team, [clinical] leader, clinicians, consultants, clinical skills trainer, screening staff, screening technicians, nurse practitioners, coordinator, clerical officer for administration, medical physicist, IT lead, other organisations, etc.) and responsibilities.
• Workforce education and training.
• Realisation of diagnostic investigations and screening tests.
• Statistical evaluation of the realisation of screening.
• Carrying out necessary interventions/treatment after screening.
• Documentation (screening process, test results, appointments, following treatment, use of data, administration, consent declined or withdrawn, storage and transfer of person-identifiable data, incident reporting, etc.).

Screening Practices

The following types of screening can be undertaken.

1. Population-based systematic screening

a) Population based approaches that attempt to systematically screen every person in the entire population.

b) Selective screening approaches that target subgroups of the population with a high prevalence of risk factors for a certain disease or condition.

The process of population-based systematic screening can be divided into the following stages {5}:

• identification of the relevant cohort  
• invitation of eligible people  
• informing eligible people about screening before the decision to participate or not is taken
• testing the people entering the screening programme (the programme ends at this point if the test results are within normal limits)  
• surveillance and forward planning if a risk for the disease exists but no immediate treatment is needed  
• diagnosis of the disease and further actions  
• treatment or intervention, taking into account valid guidelines  
• monitoring outcomes

1. Various opportunistic screening practices/usual care

(a)    The physician screens individuals occasionally during routine healthcare examinations (selective screening for individuals). The patient is presumed well or is not complaining of the disease for which screening is offered. The physician has no special reasons to suspect illness but complies with an accepted standard of good diagnostic practice.

(b)   The physician examines only those patients who consult him or her because of some complaints.

For various opportunistic screening practices for AAA no specified screening process is defined. In most cases, it is done in the primary care setting as an add-on investigation to other primary prevention investigations, or an AAA may occasionally be detected when a different indication is primarily being examined by the practitioner.

Screening in practice

Population-based systematic screening and various opportunistic screening practices can consist of {1, 6}

(a) individual medical investigations, including screening tests and interventions which altogether result in a screening programme or

(b) quality assured and evidence based screening programmes, which include all relevant interventions to reduce risk.

The implementation, realisation and financing of screening vary between the different screening practices and healthcare systems {1}:

• Governmental financing and offering of quality assured and evidence based national screening programmes (e.g. UK).
• Governmental reimbursement of costs for recommended screening interventions by independent or national providers (e.g. Australia).
• Only some health insurance agencies offer recommended screening from specified providers. Patients must decide whether they can afford it (e.g. USA).

Additional Benefits of AAA-screening

Detection of AAA by any screening procedure may act not only as a decision tool for planning elective surgery but also as a tool to intensify and supervise lifestyle modifications for the patient (i.e. smoking cessation, optimising antihypertensive pharmacotherapy,…).

Limitations of AAA-screening

The implementation of screening practices has the potential to save lives or improve quality of life because of early diagnosis of serious diseases or conditions, but it cannot guarantee protection. In any screening practice, there is a potential for harms and adverse events for patients, e.g. during the screening test, during diagnosis or during treatment. There is, for example, the potential for false positive results in individual screening tests, which may be a considerable psycho-social burden for those concerned. Additionally, false positive results can result in unnecessary investigation and treatment. On the other hand, false negative results delay the detection and final diagnosis of a disease. During the screening test, patients could be exposed to radiation or chemicals or undergo discomfort, stress or anxiety, all of which could lead to adverse effects. Therefore it is essential to establish whether, in practice, screening a healthy (risk) population leads to an improvement of relevant outcomes. {2, 7}

For abdominal aortic aneurysm screening different practices exist (population-based systematic and various opportunistic screening practices). In most countries no systematic and nationwide screening programme is implemented. Decisions about screening are made individually by primary care physicians. In addition, several cardiovascular societies have published recommendations concerning who should be screened and under which conditions. All of the recommendations require clinicians to individualise care and recommendations depending on the patient's risk and likelihood of benefit.

The following table gives an overview of the AAA screening strategies of various countries {8}.

Table 2: Overview of country-specific AAA screening practices

Published guidelines on AAA screening attempt to close the gap between the best available evidence and what physicians do in their practices. In their systematic review of guidelines on abdominal aortic aneurysm screening, Ferket et al. (2012) {11} identified seven relevant guidelines and the quality of development of each guideline included was determined by the Appraisal of Guidelines Research and Evaluation (AGREE) instrument. The AGREE instrument is a validated tool to evaluate the process of practice guideline development and the quality of reporting. {12}

Table 3: Guidelines on AAA screening (Ferket et al. 2012) {11}

Details of guidelines on AAA screening included in the systematic review of Ferket et al. {11} are reported below.

Table 4: Details of Guidelines on AAA screening (Ferket et al. 2012) {11}

The US Preventive Services Task Force (USPSTF) {7} recommends one-time screening for abdominal AAA by ultrasonography in all men aged 65 to 75 years, who have smoked at least 100 cigarettes in their lifetime. This recommendation is based on the evidence that surgical repair of large AAAs (5.5 cm or more) on the basis of screening leads to decreased AAA-specific mortality and therefore outweighs screening-associated harms in this population group. The USPSTF states that the harms of AAA-screening in men aged 65 to 75 years, who have never smoked, in men aged more than 75 years and in women in general balance or outweigh the benefits. Men aged more than 75 years are at higher risk for AAAs, but the increased presence of comorbidities and limited life expectancy decreases the likelihood that they will benefit from screening.

Summarizing the systematic review of guidelines from Ferket et al. (2012) {11} shows that most of the seven included guidelines contain recommendations that favour one-time AAA screening for men aged 65 years and older. Every guideline reasoned that abdominal ultrasonography is the primary screening test. Only one guideline group (ACC) recommended physical examination as a useful screening tool in addition to ultrasonography. The guidelines did not agree on whether a smoking history should be present or not. Additionally, four guidelines (three of them had low AGREE scores) contained disparate recommendations on screening women and middle-aged men at elevated risk, whereas guidelines with higher AGREE scores did not. The criterion for elective surgical repair in elderly men for an abdominal aortic diameter of 5.5 cm was unanimously used but there was no consensus on the management of smaller AAAs.

Most of the guidelines give recommendations for surveillance of patients with aneurysms smaller than 5.5 cm in diameter but these recommendations vary in the intensity of follow up and the cut-off points of the aorta diameter. For example, some guidelines recommend that an annual abdominal ultrasound is acceptable if the AAA is 3.0 to 4.4 cm. Others recommend that if the AAA diameter is between 4.0 and 5.4 cm, surveillance should be done every 6 to 12 months. If the AAA is <3.0 cm, some guidelines recommend no follow-up surveillance before 3 to 5 years. Other guidelines say that aneurysms 3.0 to 3.9 cm in diameter should be surveyed every 2 to 3 years, and those 4.0 to 5.4 cm in diameter should be assessed every 6 months. {11}

The typical expansion rate of AAA is around 0.3-0.4 cm per year, on average. As the expansion rate of AAAs is positively correlated to size, surveillance intervals should depend on size. As a patient's health status may change during the surveillance period, continued AAA surveillance should occur only if the patient remains a good surgical candidate and has a reasonable life expectancy. If the first-time ultrasonography screening for AAA revealed normal aortic diameter, there is no need for re-screening, as negative results appear to virtually exclude the risk for future AAA rupture. {9}

In conclusion, even if the officially accepted cut-off point for elective surgery has been set to an aneurysm size of 5-5.5 cm, the final decision about going ahead with a surgical procedure must be considered individually taking into account the option of endovascular treatment, age, comorbidities and other factors.

Question refers partly to RC-CUR10, RC-EFF24.

Ultrasonography as gold standard

Ultrasonography has been established as the gold standard technical device for screening for AAA. Different investigations show that ultrasonography is a valid diagnostic technique for the detection of AAA with both sensitivity and specificity of nearly 100%. The test is non-invasive, relatively inexpensive and fast, and patients are not exposed to ionizing radiation. Additionally, this test is highly acceptable to patients. {13-17}

More than 80% of all AAAs are detected occasionally or through ultrasonography screening {18}. If an AAA is suspected or if an AAA is detected through ultrasonography screening, further medical investigations are carried out to verify the diagnosis and define treatment, for example, computed tomography (CT) or magnetic resonance imaging (MRI).

For detection of AAAs, other diagnostic technologies, besides ultrasonography, are also used. For example abdominal palpation, CT or MRI (see result card TEC 8, {8, 13, 19}) but ultrasonography is the detection method of choice for AAA screening {13-17}.

For ultrasonography various image-guided methods are available, such as the colour-coded duplex sonography that is most often used. In brief, colour-coded duplex sonography is an ultrasound-based imaging method, using high-frequency sound waves to reflect the structure of inner organs or blood vessels. A computer receives these reflected waves and uses them to create a picture, visualizing possible pathology. Most devices can additionally study the relative velocity of the blood flow or whether the blood flow is moving towards or away from the transducer. Such measurements are based on the Doppler effect (which, within certain limits allows the accurate assessment of the direction and velocity of the blood flow by calculating the frequency shift of the flow-wave and visualizing it in colour). However, currently no standards for the display of colour-coded duplex sonographic images are available. Some laboratories use red to display arterial vessels and blue to display venous vessels; others use colours to indicate the direction of the flow either towards the transducer or away from it. To interpret the results, knowledge of the physiology and pathophysiology of blood flow in the body is therefore important. {20}

Throughout Europe, Siemens Healthcare and GE Healthcare are currently the leaders in the distribution of colour-coded duplex-sonographic technical devices. {21} Figure 1 shows an example of such a device, including the monitor and keyboard.

Figure 1: Colour-coded duplex-sonographic technical device

Figure 2 shows the duplex sonographic documentation of the transverse diameter of an infrarenal abdominal aortic aneurysm. The black area within the arrows represents the lumen of the expanded aorta.

Figure 2: Duplex sonographic documentation of an AAA

Figure 3 illustrates the transverse diameter of an infrarenal abdominal aortic aneurysm in colour-coded mode. The red colour represents arterial blood flow.

Figure 3: Transverse diameter of an AAA

Question refers partly to RC-EFF24, RC-EFF25.

• Handsearch

Screening for abdominal aortic aneurysm is used to identify this disease or condition in its preclinical and therefore potentially curable stage in apparently healthy people or people believing to be healthy. {1}

Question refers to RC-CUR1, RC-CUR8, RC-TEC1, RC-TEC2, RC-TEC3 and RC-EFF32.

Users of screening

AAA screening is usually done by physicians (predominantly general practitioners or medical doctors specialising in internal medicine; opportunistic screening practices) or medical technical assistants (population-based systematic screening). {22}

Necessary training

Usually, residents can be trained to perform ultrasound assessments adequately to identify high risk AAA patients. For the technical aspect of AAA screening, the grade and level of training seems to be more important than the type of medical discipline. {23}

Specificity, sensitivity and reproducibility

Variation in intraobserver repeatability and reproducibility of AAA screening by colour-coded duplex-sonography has been identified among studies, which may be in part related to the fact, that investigations were performed by investigators from different medical disciplines of varying grades and levels of training {24}. As poor reproducibility (above the level of 5 mm [which is accepted by the UK and USA AAA screening programmes]) may have negative impact on screening and surveillance, training and quality assurance are important factors of AAA screening.

Question refers partly to RC-CUR11, RC-CUR25 and RC-CUR12.

As mentioned in TEC 1 the screening process consists of different stages depending on whether a population-based systematic screening programme or various opportunistic screening practices are implemented.

Population-based systematic screening programme

For the National Health Services (NHS) AAA Screening Programme {5} in England standard operating procedures (SOP) are designed to inform and assist screening leads, strategic health authorities and other key stakeholders to establish and implement a new AAA population-based screening programme. The necessary elements of a screening programme, the screening pathway and quality assurance processes, and requirements for programmes are described. These SOPs state that the minimum population for selection of a population-based screening programme is 800,000 patients with detected AAA, which could be treated in a suitable medical centre. In the NHS AAA Screening Programme men are automatically invited by letter in the year they turn 65 years and men who are older than 65 years, and who have not previously been screened or treated for an abdominal aortic aneurysm, can opt in through self-referral direct to the screening programme (see CUR). The invitation comes from the local screening office and not from the general practitioner. {5}

In Sweden the population-based screening programme screens a defined healthy population (with defining a risk profile/an eligible population) by an invitation to a screening programme. Eligible people are invited by e-mail by the Register of Total Population managed by Statistic Sweden including age and gender. {8}

In the USA patients are eligible for population-based AAA screening if they have a family history of AAA, and/or if they are a man, age 65 to 75 years who has smoked at least 100 cigarettes in his lifetime and has never had an AAA ultrasound screening paid for by Medicare. {9}

Various opportunistic screening practices

For various opportunistic screening practices no specified population is defined for which AAA screening should be used. Usually, persons at risk are most likely adverted by assignments by their general practitioners.

Question refers partly to RC-CUR7, RC-TEC1, RC-TEC2, RC-TEC3, RC-SAF2 and RC-ORG11.



Ultrasonic energy was first used for medical purposes (for neurological problems) in the late 1940s. The first compound contact B-mode scanner (the patient sat in a water-filled barrel with the sensor circulating around) was developed 20 years later and the first commercial hand-held transducer was released around 1965. Since then, concurrently in various countries, sonography became used more and more frequently by a range of medical disciplines. Around 1960 the Doppler effect principle was applied for the first time for cardiovascular diagnostics. Colour-coded duplex sonographic devices were launched only after 1980, when computer technology was applied to enhance sonographic pictures. Since then the image information on ultrasound machines has improved rapidly. {25, 26}

Question overlaps partly with RC-CUR17 and RC-ETH1.

AAA may be diagnosed by a variety of methods, including physical examination (presenting as a palpable pulsatile tumour), ultrasonography, CT, MRI, angiography or radiography. CT images are three-dimensional images of the inside of the body that are generated from a large series of two-dimensional X-ray images, which are taken around a rotational axis and are especially useful for preoperative clarification of detailed anatomy and endovascular repair eligibilities. MRI, which uses the property of nuclear magnetic resonance to image nuclei of atoms inside the body and angiography, which visualises the inside of blood vessels by injecting a contrast agent into the blood vessel and imaging it using X-ray based techniques, are both more expensive than the other methods. AAA imaging by radiography is only possible in case of calcification of the aneurysm wall, which occurs in less than 50% of all AAAs {27}.

For AAA screening and determination of AAA-diameter, ultrasonography has been established as the gold standard. This technique is non-invasive, sensitive, portable and inexpensive. However, applicability may be reduced in obese people. Even if long term biological effects of diagnostic ultrasound exposure cannot be determined today {28}, most medical doctors feel that for the patient the benefits of correctly performed ultrasound outweigh the risks {29}. Nevertheless, investigations should be restricted to clearly indicated diagnostic questions. Scanning time should be held as short as possible and power should be set as low as possible, following the ALARA (As Low As Reasonably Achievable) principle {30}.

It has been proposed that population-based systematic screening programmes for AAA by ultrasonography offer a clear benefit over harm and are ethically justified as long as people are given adequate information {31}.

Ultrasonography is applicable for a wide spectrum of medical diagnostic assessments, including imaging of the heart muscle and the cardiac valves, prenatal diagnostics and gastroenterological investigations. With respect to the vascular system, colour-coded duplex sonography is applied, not only to assess potential vascular dilation, stenosis or occlusions of the carotid artery, the abdominal aortic artery and the peripheral arteries of the upper and lower extremities, but also enables detection of venous diseases, including varicosities and deep venous thrombosis. Ultrasound waves also may be used for therapeutic reasons. {32}

Question refers partly to RC-SAF4, RC-SAF7 and RC-EFF18.

Along the whole screening process, mentioned in result card TEC 1, different healthcare settings are affected.

Population-based systematic screening programme

In a population-based systematic screening programme, the testing of the people entering the programme can be undertaken in inpatient and outpatient settings. For example in the UK, ultrasound scanning for AAA is undertaken within community healthcare facilities. These are dedicated screening clinics, for example community clinics, community hospitals, mobile units or primary care facilities. Additionally, the patients themselves and general practitioners should be informed about the results of the test and whether or not referral to a vascular consultant in a hospital outpatient department or vascular centre is required (for surveillance, diagnosis and/or monitoring). The surgical treatment for AAA is undertaken in a vascular unit. {5}

In Sweden, screening is performed in imaging departments at hospitals or in separate units that specialise in ultrasonography. {8}

Various opportunistic screening practices

For various opportunistic screening practices for AAA no specified place or context is defined. Various opportunistic screening practices are usually done in the primary care setting, in most cases as an add-on investigation to other primary prevention investigations. In case of borderline positive screening results patients are usually referred to specialised units, such as a department for internal medicine with a major focus on cardiovascular diseases.

Question refers partly to RC-ORG1, RC-ORG5, RC-ORG6, RC-ORG16 and RC-ORG17.



By definition, the size of the abdominal aorta is considered normal if it does not exceed 2.5 cm as measured by ultrasound. Enlargement of abdominal aortic diameter to 2.5 cm or more is diagnosed as “Ectasia” (2.5 cm–3 cm) and to more than 3 cm as “Aneurysm” (13). Regarding the reliability and reproducibility of inner to inner diameter (excluding the arterial wall; ITI) versus outer to outer diameter (including the arterial wall; OTO) ultrasound measurement of AAA diameter, it is assumed, that the ITI wall method is more reproducible. {22}

To assess the rupture risk of an AAA, however, more reliable parameters than diameter are peak wall stress and peak wall rupture risk. {33}

The ultrasound device must be available in the institution or hospital where the test is carried out. In most case, packages with computers and software included are offered and installed by the companies. A printer is necessary, if printed pictures and reports are warranted. As already mentioned, the technique is applicable for a wide spectrum of medical diagnostic assessments, whereby one and the same device may be used by the different medical disciplines. Depending on the region of interest, investigators have to choose between transducers of different tissue-penetration depths. {34}

In UK, the screening equipment is purchased centrally and a technical equipment specification has been developed. The technical equipment consists of portable ultrasound machines, producing good quality black and white images, with digital recording devices from where data can easily be downloaded. The machines should be able to store and transfer data digitally. Additionally, an examination couch, wipes, a transducer and mobile computer media and devices are necessary. {5}

Question refers partly to RC-TEC11, RC-ECO1, RC-ECO2, RC-ORG7 and RC-ORG8.

Examinations can be performed at the bedside. As the investigation has to be performed with the patient in a supine position, application of the technology requires an examination couch, if possible, adjustable for height. To use the technology the only necessary disposable item is a water-based conducting gel to facilitate the transmission of the sound waves. As the technology is non-invasive, neither needles, nor bandages or medicines are necessary. The use of paper towels may be helpful to remove conducting gel from the skin after the investigation. {34}

Question refers partly to RC-TEC10, RC-ECO1, RC-ECO2 and RC-ORG4.

Question refers to RC-ORG10.

Question refers to RC-ORG3, RC-ORG4 and RC-SAF9.

Question refers to RC-SAF9, RC-ORG3 and RC-ORG4.



Important harms of the implementation of an AAA screening programme derive from the expected increase in the number of detected AAAs (increase of incidence) and consequently in the number of surgical interventions to repair intact or non-ruptured AAAs suitable for repair. The surgical repair of an AAA, by EVAR or OAR, is a high-risk intervention. There are serious consequences, in terms of mortality, morbidity and psychological effects, for those in whom an AAA has been detected, which are mainly measured by quality of life (QoL) scales.

OVERALL MORTALITY

The European Society for Vascular Surgery reported data from 27,635 intact AAA surgical interventions performed in 386 hospitals in ten countries of Europe and Oceania between 2003 and 2007{1}. Most interventions were OAR (18,471), though EVAR accounted for 7,578, and the rest were unspecified. The mean age of patients was 72.1 years, and 13.5% of the patients were women. The overall mortality rate, which included in-hospital mortality or 30-day mortality, was 2.83%. The overall mortality rate for OAR was 3.5%, and for EVAR 1.15%.

Schermerhorn et al. reported data from 45,660 Medicare beneficiaries undergoing elective AAA repair in the USA during the 2001–2004 period, for whom the   overall 30-day mortality was 1.2% with EVAR and 4.8% with OAR {2}. The probability of survival after 5 years was around 64% in this latter study {2}, being similar between EVAR and OAR.

RELATED MORTALITY

Among 5612 patients with intact AAA repaired by EVAR between June 1996 and February 2004, 589 had died within 8 years of follow-up and 24% of those deaths were procedure-related (141 patients) {3}. Of the 141 procedure-related deaths, 88 (14.9% of the 589 total deaths) were within the 30 days after surgery, 28 (4.8% of the 589 total deaths) due to AAA-rupture and 25 due to graft infection (4.2% of the 589 total deaths). The non procedure-related deaths were caused by cancer (117 patients, 19.9%), other cardiovascular problems (27%), pulmonary problems (6.5%), renal problems (1.5%), multi-organ failure (1.4%), unknown reasons (10.7%) and other reasons (9.2%). (According to the Committee for Standardized Reporting Practices in Vascular Surgery {4}, all deaths within 30 days after the surgical intervention were considered procedure-related deaths. The definition of “mortality related to AAA repair” varies so it must be borne in mind that published figures on procedure-related mortality could be inaccurate.)

MORBIDITY

The Medicare database reported highly frequent complications from 45,660 elective AAA repairs performed by EVAR and OAR {2}, which are detailed in {SAF-2}. This Medicare database reported, after 4 years follow-up, rupture rates of 1.8% and 0.5%, respectively, after EVAR and OAR respectively. The re-intervention rates were 9% after EVAR and 1.7% after OAR.

QUALITY OF LIFE

Inconsistent results have been found regarding the psychological effects of an AAA screening programme. An appropriate design for measuring changes in QoL for participants versus non-participants has not been identified. Therefore, it is not possible to determine whether screening for AAA affects the health-related QoL among participants. However, other information can be highlighted from the literature related to QoL.

The Viborg trial, which measured QoL using the Screen QL scale, found significantly lower scores for those invited to an AAA screening when they compared scores before versus after the scan {5}. However, the Gloucestershire screening programme reported a statistically significant fall in anxiety levels between before and 1 month after screening {6}.

A cross-sectional case-control study within the West Australia trial compared QoL before and after screening only for those who attended screening. They found increased self-perceived general health from before to after screening {7}.

The MASS trial found higher anxiety scores, no difference in depression scores, and lower scores on the SF-36 mental and physical scales at 6 weeks post-screening for those who had an AAA compared with those who had a negative screening{8}. However, other studies found that poorer self-assessed health among those who have compared with those who do not have an aneurysm could be more predictive of an aneurysm rather than a consequence of an AAA screening programme {9}.

The ADAM trial found QoL benefits for early repair using OAR compared with surveillance for small AAAs {10}.

SEXUAL DYSFUNCTION

The ADAM trial compared immediate elective repair with surveillance for small AAAs {10}. In the elective immediate OAR group more patients became impotent compared with the surveillance group.

More information about quality of life effects can be found in result card RC-SOC5.

The most important harms related to an AAA screening programme derive from the surgical interventions to repair intact or non-ruptured AAAs. Across the studies, the most relevant risk factors that predict outcomes in elective non-ruptured AAA repairs were: gender, age, preoperative morbidity, smoking and aneurysm size.

GENDER

There is no clear evidence about the effect of gender on the safety profile of the AAA screening. Chong et al. found higher long-term survival among women after open AAA repair (hazard ratio [HR] =0.72, 95% confidence interval [CI] 0.55-0.93) {11}. The UK Small Aneurysm Trial, which included 40 to 55 mm AAAs, did not find significant differences in death hazard between men and women {12}. In an observational study of 220,403 AAA patient-discharges in the USA, women had higher odds of both presenting with rupture and of in-hospital mortality compared with men, for both intact and ruptured AAA repairs {13}. A systematic review that evaluated outcomes of 2387 EVARs, reported in 39 articles, found a significantly higher risk of complications after surgery among women {14}.

Women appear more likely to suffer AAA rupture at smaller aortic diameters than males. AAAs of equal diameter represented a greater proportional dilatation in females than in males in an observational study of elective AAA repairs. This led to the authors to recommend a smaller aneurysm diameter threshold of 52 mm for repair in females rather than the 55 mm threshold commonly used in males {15}.

AGE

Increasing age is an important adverse determinant of mortality for intact AAA repair. The 2008 Report of the European Society for Vascular Surgery, which reported data from 27,635 intact AAA surgical interventions {1}, found a 1% mortality rate for patients between 51 and 55 years and nearly 5.2% mortality rate for those patients between 81 and 85 years old. Other studies have confirmed this {11,16,17}.

SMOKING

The multivariate analysis of 1020 open non-rupture AAA repairs with a mean follow-up of 57.6 months found that smoking increased general morbidity in open AAA repairs (odds ratio [OR]=2.15, 95% CI 1.03-4.46){11}. The UK Small Aneurysm Trial found that current smokers had a higher death risk than former smokers {12}.

OTHER FACTORS

Long-term mortality after open AAA repair was associated with the presence of coronary artery disease (HR= 1.36, 95% CI 1.08-1.72), chronic obstructive pulmonary disease (HR 1.59, 95%CI 1.21-2.09), chronic renal failure (HR 2.87, 95% CI 1.90-4.33), and congestive cardiac failure (HR=2.52, 95%CI 1.78-3.57) after a mean of 57.6 months of follow-up {11}. The same study found that preoperative renal failure increased postoperative renal decline and that increasing size of aneurysm increased peri-operative and long term mortality.

The UK Small Aneurysm Trial found significant increases in mortality rates after intact AAA repair with older age, larger diameter of the aneurysm (higher hazard for those with 49 to55 mm versus both 40 to44 mm and 45 to48 mm), lower ankle brachial-pressure index, and worse lung function (lower FEV₁ [forced expiratory volume in 1 second]) {12}.

Egorova et al. developed a model to define high risk patients when they are treated with elective EVAR of AAA. The model analysed the 30-day mortality of the 44,360 elective EVAR in USA. The regression model ordered the significant factors from the highest to the lowest predicted mortality as follows: renal failure with dialysis (highest score), clinically significant lower extremity ischemia, age > 85 years, liver disease, congestive heart failure, renal failure without dialysis, 80-84 years age, female, neurological disorders, chronic pulmonary disease, surgeon experience in EVAR less than three procedures, hospital annual volume in EVAR less than seven procedures and 75-79 years age {18}.

Evidence about the consequences of false positive, false negative and incidental findings of using AAA screening from a safety perspective are scarce in the literature. However, the available data indicate that the magnitude of the estimates would be low. An evaluation of the screening programme of Huntingdon (UK) found no false negatives when comparing ultrasound results with further ruptures. They also found no false positives when comparing ultrasound with computed tomography. They reported ultrasound sensitivity of 100% for detecting AAAs of 4.5 cm or more, specificity of 100% for AAAs of up to 3.0 cm, and therefore 100% for both positive and negative predictive values {19}.

Lindholt JS et al. {20} estimated accuracy from the inter-observer values. Their estimated sensitivity, specificity and predictive values of a positive test for AAA in the distal part of the infrarenal aorta were 98.9%, 99.8% and 97. 0%, respectively. The sensitivity, specificity and predictive value of a positive test for AAA in the proximal part of the infrarenal aorta were estimated at 87.4%, 99.9%, and 94.7%.

Based on the previous figures we calculated false positive and false negative rates (ratio of false positives to non-cases and ratio of false negatives to cases respectively). The false positive and false negative rates of AAA in the distal part of the infrarenal aorta using ultrasonography were 0.0013 and 0.0107 respectively {20}. The false positive and false negative rates of AAA in the proximal part of the infrarenal aorta found using ultrasonography were 0.0006 and 0.1260 respectively {20}. The incidence of false-positive scans is small and of little clinical consequence as they are likely to be detected on surveillance rescanning or confirmatory computed tomography (CT) scan. A false negative finding would result in same outcomes as those occurring in subjects for whom screening was not performed.

Ultrasound has high accuracy values when used as the first diagnostic test in AAA screening programmes; however some difficulties with visualising the aorta may occur in some cases (1.2% in the MASS trial){8}. The MASS trial, which performed the screen in non-routine clinics using portable ultrasound machines, had 1.2% non-valid ultrasound tests. Therefore, it is advisable for some cases to be re-scanned in a hospital setting by experienced sonographers.

The AAA screening clinical trials have not reported incidental discoveries of other pathologies. According to the clinical trials the frequency of incidental discovery of other pathologies in screening programmes for AAA would be low.

There is scarce information on the impact of harms on acceptability or tolerability of AAA screening. However, some factors have been identified that influence AAA screening uptake. Three randomised clinical trials evaluating the efficacy of screening for AAA reported that increasing age is negatively associated with the rate of screening attendance {31-33}. Lindholt et al. {32} found from the “Viborg trial” that the age ranges 68-70 (OR 0.82, 95% CI 0.69-0.97) and 71-73 (OR 0.59, 95% CI 0.50-0.70) had significant lower attendance rates compared with the age range 65-67, when adjusting for all other predictors. This is consistent with results from the “Chichester trial” {33} and the “Western Australia Trial” {31}. Compliances in the “Chichester trial” were 80%, 76%, 74%, and 66% for ages 65, 66-70, 71-75, and 76-80 years, respectively. Moreover, compliance figures for women were 73%, 69%, 66%, 58% for the same age ranges {33}. Lindholt et al. showed that attendance rates were above average among people with chronic pulmonary and cardiovascular conditions (OR 1.40, 95% CI 1.12-1.77) compared with healthy individuals {32}. People with mobility-disabling diseases showed low rates of attendance compared with healthy individuals, although this was not statistically significant {32}.

There is also scarce information about the determinants of uptake for other screening programmes {34}. A systematic review found only one study that measured the impact of information about benefit and risks on screening uptake. The study, a randomised controlled trial that measured women’s uptake of Down’s syndrome screening, found no increase in uptake when women received additional clinical information in different forms (detailed leaflet, audiovisual) {35}.

A recent systematic review of barriers to colorectal cancer screening uptake in participants over 65 years of age found that unpleasantness, discomfort, and perceived risks associated with performing the tests were the most commonly reported barriers related to screening tests{36}. This would not apply to the AAA screening, however, because in AAA screening the perceived risk associated with the diagnostic test is low.

Additional information of factors affecting AAA screening uptake is included in the result cards RC-SOC8 and RC-SOC9.

INTRA- OR INTER-OBSERVER VARIATION

Beales et al. systematically reviewed studies on intra- or inter-observer variations in ultrasound measurements {21}. The acceptable level of observer variation between aortic diameter measurements was suggested to be 5 mm. From the nine studies evaluated, five o presented coefficients lower that this limit. The most relevant factors they found that could affect reproducibility were: observer´s experience level, patient´s obesity and bowel gas, aortic diameter, and whether the machine was modern.

Singh et al. assessed the agreement between ultrasound and computed tomography measurements of normal and aneurysmatic aorta and the common iliac artery diameter {22}. After evaluating 3686 measurement pairs from 555 patients, they found considerable disagreement between the two techniques. Ultrasound underestimated aortic diameter in measurements of normal sized aortas (<30 mm) as compared with CT, whereas the opposite was true for aneurysmal aortas.

Singh et al. examined in an additional study the intra and inter-observer variability of CT measurements in 59 individuals. The authors found that approximately 95% of the CT measurements of the maximal infrarenal aortic diameter of the abdominal aorta could be performed with accuracy within the limit of 4 mm. The intra-observer variability for both planes was less than inter-observer variability, was increased with increasing vessel diameter, and was influenced by the experience level of the radiologist.

VOLUME–OUTCOME RELATIONSHIP

A systematic review that examined both open and endovascular repair of intact AAA found that hospital volume, surgeon volume, and surgeon´s specialisation in vascular surgery were all significant and highly associated with mortality {23}. Regarding hospital volume, a meta-analysis of 421,229 elective AAA repairs resulted in a pooled OR of mortality for high-volume institutions (≥43 OAR per annum) of 0.66 (95% CI: 0.65-0.67) as compared with low-volume institutions (<43 OAR per annum) {24}.

A meta-analysis evaluating 115,273 AAA repairs found that repairs by high-volume surgeons resulted in a decreased mortality compared with those by low-volume surgeons (pooled OR: 0.56; 95% CI 0.54-0.57), suggesting a threshold of 13 AAAs surgical repairs per year {25}. Surgeon volume had more effect than did hospital volume in a study of 5972 OARs after adjusting for other patient and hospital characteristics {26}. However, neither surgeon nor hospital volumes were found to have a significant influence on mortality after EVARs {26}.

Surgeon specialty, which implies subspecialty training and board certification, was also identified as influencing outcomes in AAA repair {27-29}. Operations performed by vascular specialist surgeons were associated with significant reductions in mortality compared with those done by general surgeons.

INCREASED BURDEN ON SURGICAL SERVICES

There is evidence that AAA screening causes an increased burden on local vascular surgical services; however its consequence on health outcomes has not been assessed. Among the 67,770 men recruited in the MASS trial, and after 10 years of follow-up, 552 elective operations took place in the invited group (n=33,883) and 226 in the control group (n=33,887). Sixty-two men underwent emergency surgery in the invited group compared with141 in the control group. These data show that the rate of elective repairs doubles with the advent of screening, and emergency ruptures are reduced by half {30}.

Specific evidence that determines the influence of the type of AAA screening on safety were not identified. However, attendance rate could influence the outcomes of AAA screening. More information on the differences between AAA screening programmes depending on attendance rate is available in the result cards RC-CUR23 and RC-ORG5.

Hospital volume, surgeon volume, and surgeon´s specialisation in vascular surgery has been found highly associated with mortality when an AAA is detected and repaired {37}, which makes advisable that both, open and endovascular repair of intact AAA be performed by high volume hospitals and high volume surgeons. More information regarding volume-outcome relationship is in the result card RC-SAF4.

Hospital volume, surgeon volume, and surgeon´s specialisation in vascular surgery have all been found to be highly associated with mortality when an AAA is detected and repaired {37}, which makes it advisable that both open and endovascular repair of intact AAA should be performed by high-volume hospitals and high-volume surgeons.

Attendance rate is another relevant factor associated with AAA screening outcomes. More information on differences in attendance rates between AAA screening programmes is available in result cards RC-CUR23 and RC-ORG5.

More information about the volume-outcome relationship is available in result card RC-SAF4.

Hospital volume, surgeon volume, and surgeon´s specialisation in vascular surgery have all been found to be highly associated with mortality when an AAA is detected and repaired, which makes it advisable that both, open and endovascular repair of intact AAAs should be performed by high volume hospitals and high volume surgeons. More information about the volume—outcome relationship is in result card RC-SAF4.

Recommendations for quality assurance that are provided in the “Organisational Aspects” domain are applicable to this question (RC-ORG3 and RC-ORG15). A summary of the recommendations applicable to the safety of an AAA screening programme are the following.

Quality of screening should be guaranteed by applying several criteria – appropriate training of staff, standardised calibration of equipment, monitoring screening outcome and performance (AAA related morbidity and mortality). All monitoring processes should be carried out using information technology (identification and collation of screening cohort; management of administration, screening and referral process; recording of AAA surgery and outcomes).

Human resources for AAA screening should include: clinical staff (director/clinical lead, ultrasound clinician, consultants in vascular units), screening staff (ultrasound screening technicians, clinical skills trainer, nurse practitioner), management/administration/technical staff (coordinator, clerical officer, medical physicist, IT lead), governance (strategic health authorities, primary care trusts, primary care providers, local screening programme, diagnostic and treatment services).

Evidence from the basic literature search (done for the whole project) was used to assess this element. Methods for reporting clinical effectiveness data and assessment of strength of evidence are as described in Domain Methodology.

Three SRs were included to assess the effect of AAA screening on the overall or ‘all-cause’ mortality outcomes (Takagi 2010; Lindholt & Norman 2008; Cosford 2007). While the SRs by Takagi et al. and Lindholt & Norman were assessed as being of medium quality, the SR by Cosford et al. was determined to be of high quality (Appendix EFF-2, Section 2). GRADE Summary of findings (SoF) tables for these series of outcomes are shown in Appendix EFF-2 Section 5.

Overall mortality in men (long-term)

The  Takagi et al. SR was the most recent SR assessing long-term (i.e. after 7 to 15 years) overall mortality in men (Takagi 2010). Four RCTs included in total 114,376 men aged 65 years or more randomised to an invitation to attend screening for AAA (n=57,181) or no invitation (control; n=57,195). Pooled analysis of the four odds ratios (ORs) showed a non-significant reduction in overall mortality in the screened group (see SoF table in Appendix EFF-2 Section 5). The fixed-effect OR was 0.98 with a 95% confidence interval (CI) of 0.95 to 1.00, P=0.06.

Overall mortality in men (medium term)

The Lindholt & Norman SR was the most recent SR assessing medium term (i.e. after 3½ to 5 years) overall mortality in men (Lindholt & Norman 2008). Four RCTs included in total 125,576 men aged between 64 and 83 years randomised to an invitation to attend screening for AAA (n=62,729) or no invitation (control; n=62,847). Pooled analysis of the four ORs showed a non-significant reduction in overall mortality in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 0.94 with a 95% CI of 0.86 to 1.20, P=0.14.

Overall mortality in women

The Cosford et al. SR was the most recent SR assessing overall mortality in women (Cosford 2007). One RCT included in total 9,342 women aged between 65 and 80 years randomised to an invitation to attend screening for AAA (n=4,682) or no invitation (control; n=4,660). The ORs showed a non-significant increase in overall mortality in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 1.06 with a 95% CI of 0.93 to 1.21, P=0.40.

Evidence from the literature basic search (done for the whole project) was used to assess this element. Methods for reporting clinical effectiveness data and assessment of strength of evidence are as described in the Domain Methodology.

Three SRs were included to assess the effect of AAA screening on AAA-related mortality outcomes (Takagi 2010; Lindholt & Norman 2008; Cosford 2007). While the SRs by Takagi et al. and Lindholt & Norman were assessed to be of medium quality, the SR by Cosford et al. was determined to be of high quality (Appendix EFF-2, Section 2). GRADE SoF tables for these series of outcomes are shown in Appendix EFF-2, Section 5.

AAA-related mortality in men (long-term)

The Takagi et al. SR was the most recent SR assessing long-term (i.e. after 7 to 15 years) AAA-related mortality in men (Takagi 2010). Three RCTs included in total 86,449 men aged 65 years or more randomised to an invitation to attend screening for AAA (n=43,211) or no invitation (control; n=43,238). Pooled analysis of the three ORs showed a significant reduction in AAA-related mortality in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 0.55 with a 95% CI of 0.36 to 0.86, P=0.008.

AAA-related mortality in men (medium term)

The Lindholt & Norman SR was the most recent SR assessing medium term (i.e. after 3½ to 5 years) AAA-related mortality in men (Lindholt & Norman 2008). Four RCTs included in total 125,576 men aged between 64 and 83 years randomised to an invitation to attend screening for AAA (n=62,729) or no invitation (control; n=62,847). Pooled analysis of the four ORs showed a significant reduction in AAA-related mortality (see SoF table in Appendix EFF-2 Section 5). The fixed-effect OR was 0.56 with a 95% CI of 0.44 to 0.72, P<0.00001.

AAA-related mortality in women

The Cosford et al. SR was the most recent systematic review assessing AAA-related mortality in women (Cosford 2007). One RCT included in total 9,342 women aged between 65 and 80 years randomised to an invitation to attend screening for AAA (n=4,682) or no invitation (control; n=4,660). The OR shows a non-significant increase in AAA-related mortality in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR is 1.99 with a 95% CI of 0.36 to 10.88, P=0.43.

This research question was not assessed in any of the included literature.

NA

This research question was not assessed in any of the included literature in this domain, but since it is covered in the Safety domain in result card SAF1, SAF1 is referred to for EFF3.

NA

This research question was not assessed in any of the included literature.

NA

Evidence issued from the basic literature search (done for the whole project) is used to assess this element. Methods for reporting clinical effectiveness data and assessment of strength of evidence are as described in Domain Methodology.

One SR was included to assess the effect of AAA screening on the incidence of ruptured AAA (Cosford 2007). This SR was determined to be of high quality (Appendix EFF-2, Section 2). GRADE Summaries of findings (SoF) tables for this outcome for men and women are shown in Appendix EFF-2 Section 5.

Incidence of ruptured AAA in men

The Cosford et al. SR was the most recent SR assessing the incidence of ruptured AAA in men (Cosford 2007). One RCT included a total of 6,433 men aged between 65 and 80 years randomised to an invitation to attend screening for AAA (n=3,205) or no invitation (control; n=3,228). The ORs showed a significant reduction in the incidence of ruptured AAA in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 0.45 with a 95% CI of 0.21 to 0.99, P=0.048.

Incidence of ruptured AAA in women

The Cosford et al. SR was the most recent SR assessing incidence of ruptured AAA in women (Cosford 2007). One RCT included in total 9,342 women aged between 65 and 80 years randomised to an invitation to attend screening for AAA (n=4,682) or no invitation (control; n=4,660). The odds ratio (ORs) showed a non-significant increase in the incidence of ruptured AAA in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 1.49 with a 95% CI of 0.25 to 8.94, P=0.66.

This research question was not assessed in any of the included literature.

NA

Morbidity was assessed by Cosford et al., but the SR did not find any RCTs for outcomes that, for instance, were associated with complications of surgery such as distal embolus, haemorrhage and graft failure, coronary and cerebrovascular events or renal complications (Cosford 2007). However, as this research question is also covered in the Safety domain in SAF1, this is referred to for EFF7.

NA

This research question was not assessed in any of the included literature in this domain, but as it also is covered in the Description and Technical Characteristics (TEC) domain, relevant result cards within TEC are referred to for EFF16.

NA

This research question was not assessed in any of the included literature.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Health Problem and Current Use of the Technology domain (CUR), relevant result cards within the CUR domain are referred to for EFF20.

NA

This research question was not assessed in any of the included literature.

NA

Evidence issued from the basic literature search (done for the whole project) is used to assess this element. Methods for reporting clinical effectiveness data and assessment of strength of evidence are as described in Domain Methodology.

One SR was included to assess the effect of AAA screening on planned and emergency operations (Lindholt & Norman 2008). The SR was determined to be of medium quality (Appendix EFF-2, Section 2). GRADE SoF tables for these outcomes are shown in Appendix EFF-2 Section 5.

As this research question also is covered in the Organisational Aspects domain (ORG), result card ORG19 is therefore referred to for EFF19.

Planned operations in men (long-term)

The SR by Lindholt & Norman was the most recent SR assessing long-term (i.e. after 7 to 15 years) planned operations in men (Lindholt & Norman 2008). Three RCTs included in total 86,479 men aged between 64 and 83 years randomised to an invitation to attend screening for AAA (n=43,167) or no invitation (control; n=43,312). Pooled analysis of the three ORs showed a significant increase in planned operations (long-term) in the screened group (see SoF table in Appendix EFF-2 Section 5). The fixed-effect OR was 2.81 with 95% CI from 2.40 to 3.30, P<0.00001.

Planned operations in men (medium term)

The SR by Lindholt & Norman was the most recent SR assessing medium term (i.e. after 3½ to 5 years) planned operations in men (Lindholt & Norman 2008). Four RCTs included a total of 125,576 men aged between 64 and 83 years randomised to an invitation to attend screening for AAA (n=62,729) or no invitation (control; n=62,847). Pooled analysis of the four ORs showed a significant increase in planned operations (medium term) in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 3.27 with 95% CI from 2.14 to 5.00, P<0.00001.

Emergency operations in men (long-term)

The SR by Lindholt & Norman was the most recent SR assessing long-term (i.e. after 7 to 15 years) emergency operations in men (Lindholt & Norman 2008). Three RCTs included a total of 86,479 men aged between 64 and 83 years randomised to an invitation to attend screening for AAA (n=43,167) or no invitation (control; n=43,312). Pooled analysis of the three ORs showed a significant reduction in emergency operations in the screened group (see SoF table in Appendix EFF-2 Section 5). The random-effect OR was 0.48 with 95% CI from 0.28 to 0.83, P=0.009.

Emergency operations in men (medium term)

The SR by Lindholt & Norman was the most recent SR assessing medium term (i.e. after 3½ to 5 years) emergency operations in men (Lindholt & Norman 2008). Four RCTs included a total of 125,576 men aged between 64 and 83 years randomised to an invitation to attend screening for AAA (n=62,729) or no invitation (control; n=62,847). Pooled analysis of the four ORs showed a significant reduction in emergency operations in the screened group (see SoF table in Appendix EFF-2 Section 5). The fixed-effect OR was 0.55 with 95% CI from 0.39 to 0.76, P=0.0003.

This research question was not assessed in any of the included literature.

NA

Return to work is assessed by Cosford et al., but the SR did not find any RCTs for this outcome (Cosford 2007). However, as this research question is also covered in the Social Aspects domain in result card SOC3, this is referred to for EFF11.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Social Aspects domain in result card SOC3, this is referred to for EFF12.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Social Aspects domain in result card SOC3, this is referred to for EFF13.

NA

Evidence issued from the basic literature search (done for the whole project) was used to assess this element. Methods for reporting clinical effectiveness data and assessment of strength of evidence are as described in Domain Methodology.

One SR was included to assess the effect of AAA screening on QoL in terms of state anxiety, depression and mental QoL (Collins 2011). This SR was determined to be of high quality (Appendix EFF-2, section 2). GRADE Summaries of findings (SoF) tables for these outcomes are shown in Appendix EFF-2 Section 5. No information on gender or age distribution was provided. Outcomes assessed were anxiety, depression and mental QoL. Anxiety was measured using STAI, the state scale of the state-trait anxiety inventory (Spielberger 1970), depression was measured using HADS, the state Hospital Anxiety and Depression Scale (Zigmond & Snait 1983), whereas mental QoL was measured using Short Form Health Survey SF-36 (Ware & Sherbourne 1992).

As this research question also is covered in the Social Aspects domain, result cards SOC1, SOC2, SOC3 and SOC4 are referred to for EFF9.

Anxiety

In the SR by Collins et al., in the one RCT that assessed anxiety, a total of 1,956 participants were randomised to an invitation to attend screening for AAA (n=1,230) or no invitation (control; n=726). Anxiety was significantly reduced in the screened group: the standard mean difference (Std.MD) was -0.12 with a 95% CI of -0.21 to -0.02 ((see SoF table in Appendix EFF-2 Section 5) P not indicated).

Depression

In the Collins et al. SR, depression was assessed in the same RCT, which included a total of 1,956 participants randomised to an invitation to attend screening for AAA (n=1,230) or no invitation (control; n=726). Depression was significantly reduced in the screened group:  the Std.MD was -0.11 with 95% CI from -0.20 to -0.02 (P was not indicated; see SoF table in Appendix EFF-2 Section 5).

Mental Quality of Life (QoL)

Mental QoL was also assessed in the RCT included in the Collins et al. SR in which a total of 1,956 participants were randomised to an invitation to attend screening for AAA (n=1,230) or no invitation (control; n=726). Mental QoL score was better in the screened group but not significantly so: Std.MD was 0.07 with 95% CI from -0.02 to 0.16 (P was not indicated; see SoF table in Appendix EFF-2 Section 5).

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Social Aspects domain (SOC), result cards SOC1, SOC2, SOC3 and SOC4 are referred to for EFF10.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Social Aspects domain (SOC), result cards SOC1, SOC2, SOC3 and SOC4 are referred to for EFF25.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Economic and Ethical Aspects domains (ECO and ETH), result cards ECO4, ETH1 and ETH7 are referred to for EFF14.

NA

The SR by Cosford et al. was the only SR to report patients’ acceptance of AAA screening programmes (Cosford 2007). This SR was determined to be of high quality (Appendix EFF-2, Section 2). However, this was not a pre-defined outcome, and the authors report acceptance rates from the RCTs included in the SR in narrative form only.

Cosford et al. reported acceptance rates ranging between 63% (Norman 2004) and 80% (Ashton 2002). In one trial the acceptance rate increased from 63% to 70% when, after randomisation, patients who were identified as too unwell or previously scanned were excluded (Norman 2004).

According to the SR, only one trial recorded acceptance rates by age (Scott 1995). In this trial men and women aged 65 accepted the invitation to screen most often (81% and 73% respectively), but acceptance decreased with age and was lowest for men and women aged 76 to 80 years (66% and 58% respectively).

As this research question also is covered in the Social Aspects domain (SOC), result card SOC5 is referred to for EFF15.

This research question was not assessed in any of the included literature in this domain, but as it also is covered in the Description and Technical Characteristics (TEC) domain, relevant result cards within TEC are referred to for EFF16.

NA

This research question was not assessed in any of the included literature.

NA

This research question was not assessed in any of the included literature.

NA

This research question was not assessed in any of the included literature.

NA

This research question was not assessed in any of the included literature.

NA

Evidence issued from the basic literature search (done for the whole project) is used to assess this element. Methods for reporting data are as described in Domain Methodology.

As no tools at the present are available for assessing the quality of reliability and agreement studies, no grading to indicate strength of evidence has been performed for these outcomes.

One SR was included to assess the variation of AAA screening interpretation in terms of variation in intra-observer repeatability and inter-observer reproducibility of infra-renal aortic diameter measurements using ultrasound (Beales 2011). This SR was determined to be of medium quality (Appendix EFF-2, Section 2).

Bland-Altman plots, a method based on the differences in observed values compared with the means of measured values was used to assess these outcomes in eight of the nine included studies (Bland & Altman 1986), whereas one study used a multilevel regression approach, i.e. generalised estimating equations (GEE) for the extraction of components of variation, separating intra-observer variation from inter-observer variation (GEE 2012). By using the GEE method, the number of assumptions for this analysis were reduced, which allowed variations to be reported in terms of standard deviations and appropriate definitions of measurement reliability derived from those standard deviations.

There were wide variations between the nine included studies in terms of numbers of measurements (from 10 to 112), participant demographics (age and gender) and types of ultrasound machine (all different). Various techniques of aortic diameter measurement techniques (calliper endpoints) were used, i.e. diameter measurement between aortic inner layers (ITI), between aortic inner and outer layers (ITO), or between aortic outer layers (OTO), and in both anteroposterior (AP) and transversal (TS) planes. Measurements were done on aneurysmal and normal aortas. In all studies, observers were blind to the results from the other observers, but they had different backgrounds in terms of discipline, grade or level of experience and training.

Intra-observer repeatability

The SR by Beales et al. was the only SR from the basic literature search that assessed intra-observer repeatability. Intra-observer repeatability was assessed using Bland-Altman plots by calculating repeatability coefficients in seven studies and using the GEE method in one study (Bland & Altman 1986; GEE 2012). Data for this outcome were not available for one of the nine included studies.

The intra-observer maximum AP mean difference ranged from 0.03 to 4.8 mm, and for TS from 0.2 to 1.9 mm. Beales et al. indicated diameter intra-observer repeatability coefficients, ranging from 1.6 to 7.5 mm for AP (and from 2.8 to 15.4 mm for TS). The National Health Service Abdominal Aneurysm Screening Programme (NAAASP 2009) suggested that 5 mm is an acceptable level of observer variation between aortic diameter ultrasound measurements. Authors suggested that aortic measurements by the same practitioner may vary significantly, but did not provide any statistical support for this statement, and the diameters (ITI, ITO or OTO) measured varied between studies. In addition, numbers of observers were few in eight of the nine included studies. It was difficult to draw a definitive conclusion from the review, but it indicated overall acceptable intra-observer repeatability.

In the studies included by Beales et al. numbers of observers ranged from 1 to 4, except for one study which had 24 observers (Hartshorne 2011). However, Hartshorne et al. included exclusively assessments of static images of aortas of different sizes, whereas the other eight studies included real-time examinations in which the relevant images to enable aortic diameter measurement were acquired. This study was nevertheless highlighted by the SR authors as being the only one that had used the GEE method. In this study, the intra-observer AP mean repeatability coefficients varied from 1.6 to 2.0 mm with individual repeatability coefficients ranging from 0.8 to 6.1 mm (TS measurements were not performed in this study), which are mainly below the acceptable level of variability of 5 mm (NAAASP 2009).

Intra-observer variability for ITI and OTO aorta diameter measurements

Hartshorne et al. was the only study that assessed possible differences in intra-observer variability according to different calliper endpoints of aortic diameter measurements (i.e. diameter measurements of ITI walls versus OTO walls), as well as according to differences in observers’ background disciplines and experience (screening technicians versus vascular sonographers). In this study, 13 screening technicians and 11 vascular sonographers examined 60 aortic static images (not live). Among the sonographers, six had more than 10 years’ experience and only one had less than 1 year of experience, whereas only two screeners had more than 10 years’ experience and five had less than one year. While all 13 screeners routinely used ITI, five sonographers used OTO and six both ITI and OTO in their routine practice. When 15 images were each measured twice in random order by all 24 observers, there was no significant difference between the mean repeatability of ITI, 1.6 mm (range 0.8-5.2 mm) and that of OTO, 2.0 mm (range 0.5-6.1 mm). For ITI, there was no significant difference between the mean repeatability of screeners, 1.7 mm (range 0.8-5.2 mm) and that of sonographers 1.4 mm (range 0.9-2.4 mm; P=0.27). For OTO, on the other hand, the mean repeatability was significantly better for sonographers at 1.4 mm (range 0.6-2.6 mm) compared with screeners, mean 2.5 mm (range 1.1-6.1 mm; P=0.037).  It was, however, not possible to ascertain, using these data, the effect of the sonographers’ longer experience since screeners, as opposed to sonographers, did not use OTO in their routine practice.

Inter-observer reproducibility

The SR by Beales et al. is the only SR from the basic literature search that assessed inter-observer reproducibility. Inter-observer reproducibility was assessed using Bland-Altman plots in eight studies and by the GEE method in one study (Bland & Altman 1986; GEE 2012).

For AP, the limits of agreement (reproducibility coefficients) for the diameter measurements ranged between -1.9 to +1.9 mm and -10.4 to +10.5 mm (all nine studies), whereas for TS, the largest limit of agreement was -5.6 to +5.2 mm (only two studies assessed TS diameters). According to Beales et al., five of the nine studies included had acceptable inter-observer reproducibility. For the study that involved 24 observers and used the GEE method (Hartshorne 2011), as opposed to the 1-4 observers in the eight others, the mean reproducibility coefficients were 3 mm (95% CI 2.4-3.6 mm) for ITI and 4.2 mm (95% CI 3.5-4.9 mm), both of which were below the acceptable level of variability of 5 mm (NAAASP 2009). Although the authors of the SR do not draw any conclusions about inter-observer reproducibility, the results indicate overall acceptable inter-observer reproducibility regardless of whether diameters are measured as ITI, OTI or OTO.

Inter-observer variability for ITI and OTO aorta diameter measurements

Hartshorne et al. was the only study that assessed possible differences in inter-observer variability according to different calliper endpoints of aortic diameter measurements (i.e. diameter measurements of inner-to-inner walls [ITI] versus outer-to-outer walls [OTO]), as well as according to differences in observers’ background disciplines and experience (screening technicians versus vascular sonographers) (Hartshorne 2011). In this study, in which 13 screening technicians and 11 vascular sonographers examined 60 images, mean reproducibility coefficient for ITI was significantly better than for OTO when measuring AP (TS was not measured in this study). Mean reproducibility coefficient was 3.0 mm (95% CI 2.4-3.6 mm) for ITI and 4.2 mm (95% CI 3.5-4.9) for OTO (P<0.05), but both remained acceptable according to NAAASP, i.e. less than 5 mm (NAAASP 2009). Hartshorne and collaborators performed a corresponding analysis, excluding observers with less than 1 year’s experience. In this group of 8 screening technicians and 10 sonographers mean reproducibility coefficients were 3.2 mm (95% CI 2.6-3.8 mm) for ITI and 3.8 mm (95% CI 3.1-4.5 mm) for OTO. It was not possible, however, to ascertain that there was no effect of background discipline, because the screening technicians, as opposed to sonographers, did not use OTO in their routine practice.

Impact of ITI and OTO on the threshold for surveillance and referral for treatment

Hartshorne et al. grouped the 60 images into four categories to assess the impact of ITI versus OTO on the threshold for surveillance and referral for treatment. Results presented in the table below (Table 1- EFF33) indicated that the ITI method would detect fewer aneurysms than using OTO.

Table 1 – EFF33 : Size categories using ITI vs size categories using OTO using 1440 measurements

<30 mm is considered normal and requires no further surveillance (adapted from Hartshorne et al. 2011)

30-45 mm is considered a small aneurysm requiring yearly assessments

45-55 mm is considered a medium large aneurysm requiring 3-monthly assessments

>55 mm is considered a medium large aneurysm requiring immediate surgery

However, as indicated earlier, this study did not assess live images, and half of the observers were screening technicians who had less experience than vascular sonographers, and who used only ITI in their practice routine. These factors meant that a definite conclusion could not be drawn based on these data about the thresholds for surveillance and referral for treatment.

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Safety domain (SAF), result card SAF3 is referred to for EFF22.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Safety domain (SAF), result card SAF3 is referred to for EFF23.

NA

This research question was not assessed in any of the included literature in this domain, but since it also is covered in the Safety and the Economic domains, result card SAF1 and relevant cards within the ECO domain are referred to for EFF24.

NA

The authors consulted Finnish experts in the field of vascular surgery to help describe the possible systematic organisation of AAA screening and the types and amounts of resources needed.

The types of resources used in AAA screening are also described in other domains: Description and technical characteristics of the technology, Health problem and current use of the technology, and Organisational domain. Please see for example RC-TEC9, RC-TEC10, RC-TEC12, RC-ORG3, RC-ORG7, RC-ORG8 and RC-ORG9. This result card describes the types of resources used when delivering AAA screening in the Finnish healthcare setting, due to the context-specific nature of economic evaluation.

One possible pathway for AAA screening and follow-up is presented in Table 2 (translated from {3}). According to this pathway, for AAA screening and follow-up for small and medium AAAs, the most critical types of resources are ultrasound devices, rooms and trained personnel to do the examinations. For example, sonographers and vascular nursing staff could be trained to perform the screening but where there are positive findings the screened person should have the opportunity to discuss this with a physician. This has been proposed by cardiovascular experts in Finland but it is not in use at the moment. This also differs from the model used in the cost-effectiveness analysis in this domain since no data was available for this type of organisation.

Resources (personnel, rooms) for vascular surgery units would be needed to deal with the increase in consultation visits caused by the screening. Furthermore, the units must also be prepared for an increased need for CT scans to confirm the diagnosis and size of the aneurysm. Finally, screening will significantly increase the need for elective repair of AAA, and all relevant constituent resources should be considered.

The types of resources needed for population-based AAA screening compared with no population-based AAA screening differ in terms of organisation of screening programme. The additional requirements of the screening programme include, for example, identification of the screening population, an invitation system, additional personnel and education of staff needed for screening, and development and distribution of information. The types of resources needed for ultrasound, CT and surgery are similar in both alternatives; only the amounts of resources differ. The numbers of devices, personnel, and relevant premises (examination, operating rooms, emergency department) would, of course, be expected to differ between population-based screening and no screening.

The economic evaluation of population-based AAA screening compared with no population-based AAA screening in this domain is undertaken from the Finnish healthcare payer perspective. As it is not wholly realistic to conduct a cost-effectiveness analysis applicable to all European countries, Finnish data provides a useful example of a base case analysis. The appropriate structure and data inputs of the model are likely to differ from country to country. In addition, the primary investments (training, new equipment etc) needed to start a new screening programme are not included in the cost-effectiveness analysis.

Registry data: For the ‘no systematic screening’ scenario the number of elective and emergency operations per year was estimated using data from Finnish national registries, according to the current situation in Finland. The data on operations was based on the National Hospital Discharge Register (HDR), which includes details on all hospital visits and episodes in Finland. The estimate of ruptured AAAs was based on the number of emergency operations and the AAA-related deaths from the National Cause of death –register and HDR. The ICD10 –codes used were I71.3, I71.4, and I71.8.

Modelling: The decision-analytic modelling was used to simulate how the number of elective and emergency operations would change as a result of a screening programme.

Amounts of resources used in AAA screening are also described in the Organisational domain; please see RC-ORG3, RC-ORG7, RC-ORG8, RC-ORG9 and RC-ORG16. This result card estimates the amounts of resources used when delivering AAA screening but the estimation is based on decision-analytic modelling done using Finnish register-based data.

Table 3. Estimated difference in amounts of resources needed for population-based screening compared with no population-based AAA screening, per cohort of 100 000 people. Figures in ‘population-based screening’ are estimates based on the decision-analytic modelling, and figures in ‘no population-based AAA screening’ are based on registry data from Finland.

The amounts of resources needed for population-based AAA screening differ markedly from the corresponding figures for current practice, ie. no population-based AAA screening. The estimated numbers of operations for both alternatives are presented in Table 3 for a cohort of 100 000 people. The numbers of operations in the table should not be seen as the total number of AAA operations per year, because the total number would also include patients that belong to older cohorts whose AAA had been detected in the screening (or any patients whose AAA is ruptured).

The unit costs of AAA screening in Finland were estimated using the actual cost data from AAA patients in the hospital district of Helsinki and Uusimaa from the year 2010. Unit costs for ultrasound examination, computer tomography, and elective and emergency surgery for AAA were estimated. Costs of long-term consequences (e.g. possible rehabilitation after the intervention) were not included. The cost estimates include only the costs for healthcare sector; other costs to society, and private costs for patients and their relatives were excluded from this analysis.

The Finnish data were used when conducting the base case cost-effectiveness analysis. To estimate the possible variation in unit costs within Europe, other EUnetHTA partners were asked at the beginning of 2012 to estimate the corresponding costs in their countries. The variations in unit costs are reported in this result card (Table 4).

Unit costs were estimated in seven countries and are presented in Table 4 below. The estimates vary greatly from country to country, as could be expected. The estimated costs of pre- and post-operative care, follow-up and overheads, differ between countries (Table 4), and were derived using a variety of methods, as presented in Table 5. Danish and Swedish costs are based on case-mix or micro-costing estimates. Finnish costs are either charges or micro-costing estimates, and Spanish costs are charges or case-mix estimates. Slovakia reported only charges and Croatia only case-mix estimates.

Table 4. Unit costs of relevant resource items in different countries (cost in € except for Sweden [SEK]. Blank: no response). The estimates include: ¹pre-operative care; ²post-operative care; ³follow-up; ⁴overhead costs/fixed costs

Table 5. The methods used to estimate the unit costs reported in Table 4.

Estimates of the relevant unit costs were obtained in a survey sent to EUnetHTA partners in December 2011 (with reminders in 2012). One should be careful when comparing these figures since we did not ask the respondents to report systematically from which year the cost estimates were derived, or what was the source/reference for the costs. In addition, there is little information about the costs of invitation to screening. This cost may vary depending on the way the invitation process is (and can be) organised in a country. Possible costs associated with, e.g., awareness campaigns concerning population-based screening, should also be included.

The effectiveness of population-based AAA screening compared with no screening is reported in much more detail in the Effectiveness domain. This result card reports the incremental effectiveness based on the systematic literature review done in this domain, and on the basis of the decision-analytic modelling undertaken.

Literature review

Summaries of the incremental effects of screening obtained in previously published studies are provided in the literature review.

Modelling

The incremental effects of population-based AAA screening compared with no screening were also analysed using the decision-analytic model (see Domain Methodology), using the remaining expected lifetime of the screened population (in Finland) as the time horizon. The incremental effectiveness is reported in LYG. In the report of AAA screening in Finland {3} the life expectancy after elective AAA surgery was found to be similar to that of the control cohorts.

Systematic literature review

According to the current literature AAA is largely an asymptomatic disease prior to its rupture; the effects of AAA screening are seen primarily in the prolonged lifetime of the population. In all the 26 cost-effectiveness analyses included, a positive effect on the lifetime of the screened population was observed. Detailed data on the LYG was available in seven of the 26 studies {3, 10, 18, 24-27} and data on quality-adjusted life years (QALY) gained was also available from seven studies {18, 24, 26, 28-31}. The LYG ranged in the studies for men from 0.013 to 0.097 and for women from 0.011 to 0.02. The QALY gained ranged from 0.011 to 0.07 (reported for men only).

Three studies also included women as well {3, 32, 33}. One of them included only women and found a LYG of 0.02, which is also within the range of men’s results {32}. The authors concluded, however, that the results should be interpreted with some caution, because female-specific epidemiological data are scarce. Two other studies contained both men and women. The second oldest reviewed study concluded that screening should include both men and women {33}. The most recent study found a LYG of 0.011 for women and 0.027 for men, and concluded that AAA screening appears to be effective for both sexes but the estimate for women is less precise {3}.

Four systematic reviews on cost-effectiveness were identified, published between 2007 and 2010 and covering literature (at the latest) up to June 2008. Three of these reviews concluded that AAA screening increases the overall life expectancy of the screened population. One review was more critical, stating in its conclusions that most health economic evaluations have employed a number of optimistic assumptions in favour of AAA screening and that further analyses are needed {34}. This review also included other types of screening than population screening for AAA and hence its focus was somewhat different.

Detailed results are available as Appendix ECO-2. Included studies are summarised in more detail also in RC-ECO5.

Modelling

According to the base case analysis, the incremental effectiveness of population-based one-time ultrasound screening for 65-year-old men in Finland would be approximately 0.027 LYG compared with no screening (11.551 vs. 11.524 life years, respectively), using a 3% discount rate. For women, the incremental effectiveness would be smaller, 0.013 LYG (15.687 vs. 15.674 for screening and no screening, respectively). Without discounting the corresponding figures were 0.041 LYG for men and 0.022 LYG for women.

Systematic literature review

All 26 included studies found a positive impact overall of AAA screening on the life expectancy of the screened population. This increase ranged from 4 to 48 days for LYG and from 4 to 26 days for QALY gained. The figures are low in absolute numbers, since the total number of LYG is divided between all those invited to screening. The benefit is, however, experienced in a much more substantial manner in reality by those individuals who undergo a life-saving elective repair of AAA. For them the benefit may be counted in years – provided that the operation is successful. The impacts of screening in these studies are similar to those associated with other screening technologies.

We have cited above, in detail, mainly studies that reported upper and lower limits of the range of findings. Three key studies were not explicitly referenced but belong to the analysis {47–49}.

The systematic review within this domain focuses on economic analyses. Hence the literature on health effects may not be conclusive. Results within the clinical effectiveness domain should be consulted for a more inclusive view.

Abdominal aortic aneurysm is a life-threatening condition and AAA screening aims to detect aneurysms in the asymptomatic phase before risk of rupture. The screening and possible subsequent elective operations are potentially life-saving interventions. This means that the appropriate time horizon for the analysis is the expected lifetime of the screened population. The life expectancy of the 65-year-old population in Europe was estimated using EuroStat statistics (http://epp.eurostat.ec.europa.eu/tgm/table.do?tab=table&init=1&language=en&pcode=tsdde210&plugin=1).

Systematic literature review

The time horizon in the included studies was typically expected lifetime or 20 years or more. Few studies employed a time horizon of less than 10 years. Two included studies reported the same study, only one had a time horizon of 7 years and the other with a horizon of 10 years.

Modelling

In the base case analysis, the life expectancies of 65-year-old Finnish men and women were used: 17.5 and 21.5 years respectively. At the European level, the mean life expectancy for 65 year olds is 17.3 years for men and 20.9 years for women.

Systematic literature review

An evidence table from the systematic review described in the domain methodology was used to compile this answer. The incremental cost-effectiveness ratios (ICERs) reported in economic analyses are extremely difficult to compare in an exact manner, since they are heavily dependent on e.g. the healthcare setting, the methods of the original analyses, the timeframe and changes in currency rates over time. Therefore, no exact threshold levels were used, but instead a descriptive analysis of the data was performed, considering the numbers in euros and using foreign currency rates during the first week of May 2012. Detailed results of each study are available in the evidence table in Appendix ECO-2 to this result card.

In some cases the authors listed more than one ICER value reflecting, for example, changing assumptions about follow-up times. In this result card the values reflecting the longest available time horizon were used whenever available.

Modelling

Decision-analytic modelling was used to estimate the ICERs. A previously constructed model combining a decision-tree and a Markov model was used {2}, with some modifications {3}. The structure of the model is presented in the domain methodology. The analysis was done from the healthcare provider’s perspective using a time horizon of the expected remaining life time of the 65- year-old population. Base case analysis was done using Finnish data and data from the literature. The analysis was conducted using TreeAge Pro HealthCare software (version 2011, TreeAge Software Inc.).

Systematic literature review

Twenty-six studies identified in the literature review contained either a cost-effectiveness analysis (CEA) or cost-utility analysis (CUA) of population-based ultrasound screening for AAA compared with no screening. Of these, 19 studies were published less than 10 years ago (2003 or later).

The time horizon in the included studies was typically expected lifetime or 20 years or more. Only a few studies employed a time horizon of less than 10 years. Two included studies actually reported the same study, but one had a time horizon of 7 years and, the other, 10 years {10, 35}.

A clear majority of CEA or CUA analyses included men either as a single cohort (typically 64 or 65 years of age) or as a group between 64 and 75 years of age. Somewhat younger (from 50 years onwards) or older men were included in 6 studies {20, 33, 36-39}. Women were included in three studies only (Mäklin 2011, Wanhainen 2006, Russell 1990). All but three studies originated from the Nordic countries, the UK or North America. The three other studies were from Italy {28} and the Netherlands {25, 36}, one of them partly from Norway.

The ICER varied considerably across studies as expected since the analyses had been made in different healthcare systems, during different times and using different time horizons. The lowest ICER was found in a Danish study published in 2010 {26}, with ICERs of 157 € per LYG and 179 € per QALY. The highest ICER was likewise found in a Danish study published in 2009 {2}, with an ICER of 43 485 €/QALY (see comment section below).

In 22 of the 26 studies the cost per LYG or per QALY was lower than approximately  – and in several of them clearly less. This was the case for 17 of the 19 studies published less than 10 years ago (2003 or later).

In four studies the cost was clearly higher than approximately 10 000 €, expressed either as €/LYG or €/QALY {2, 35, 38, 40}. These results, however, may be less reliable (see comment section below). Five out of seven studies published more than 10 years ago (2002 or earlier) indicated an ICER at the very low or very high end of the range.

The four studies that observed higher ICERs than the remaining studies, originated from Canada {38}, Denmark {2}, and the UK {35, 40}. More recent studies indicating a lower ICER also originated from all these countries.

The most recent of the three studies, which included women as well as men, concluded that screening women may also be cost-effective, but in the absence of information on women the analysis was done mainly with information concerning men, and hence this result should be interpreted with caution {3}. The second study,  which was the only study considering women only, concluded that screening women may be cost-effective and that women should be included in future evaluations of AAA screening {32}. The third study concluded that a screening programme should include both men and women {33}.

Four systematic literature reviews were also identified, published between 2007 and 2010 and covering literature up to June 2008 at the latest{34, 41-43}. One of them concluded that AAA screening will probably gain additional life years and quality of life for men aged 65 years or older at acceptable extra costs {41}. Another concluded that AAA screening seems to be both effective and cost-effective, but that economic evaluations do not always take into account peri- and postoperative mortality {42}. The third review was more critical, concluding that most of the existing health economic evaluations have employed optimistic assumptions and included too few sensitivity analyses, and hence further cost-effectiveness analysis of AAA screening is recommended (Ehlers 2008). This review also included other types of screening for AAA apart from population screening and hence its focus was somewhat different. Four out of five of its authors were also authors of the Danish study (Ehlers 2009) that found the highest ICER for AAA screening. The fourth review concluded that the cost-effectiveness of AAA screening may be acceptable, but needs further expert analysis, and that the evidence to demonstrate a benefit in women is insufficient {43}.

In conclusion, the currently available evidence from 26 CEA or CUA analyses supports the cost-effectiveness of this technology in many European settings, at least in the UK, the Scandinavian countries, the Netherlands and Italy. A more specific assessment can only be done in specific settings using local data and values.

Detailed characteristics of the studies are available as Appendix ECO-2.

Modelling

Base case analysis

Table 6 summarises the results of the base case cost-effectiveness analysis. The ICER of population-based AAA screening in Finland would be 8433€ per LYG, when ultrasound screening is offered once to 65-year-old men. The ICER for women is lower at 7198€/LYG, due both to, lower incremental costs and lower incremental effectiveness of AAA screening compared with no population-based AAA screening. The results for women should be interpreted with caution as they are heavily based on data for men, and on assumptions that the natural course of AAA is similar in men and women.

Table 6. The results of the base case analysis of cost-effectiveness of population-based AAA screening compared with no population-based screening in Finland. The analysis was run for men and women separately.

Sensitivity analysis

The robustness of the results was tested using probabilistic sensitivity analysis, varying most of the parameter values simultaneously. The results of the probabilistic sensitivity analyses for both sexes are shown as cost-effectiveness acceptability curves in Figures 3 and 4. The cost-effectiveness acceptability curves represent the probability that intervention is cost-effective at different threshold values. In the base case analysis with a willingness-to-pay threshold of 24 000 €/LYG, population-based AAA screening for men is cost-effective with a probability of 95%. For women, the corresponding threshold value is 10 300€/LYG.

 Figure 3. The cost-effectiveness acceptability curve, AAA screening for men (probabilistic sensitivity analysis).

Figure 4. The cost-effectiveness acceptability curve, AAA screening for women (probabilistic sensitivity analysis).

Also, a one-way sensitivity analysis was undertaken for some key parameters (Table 7) in order to gauge the effect of these on the results. Varying the attendance rate at the screening had only a minor effect on the ICER. Variation of the discount rate had a stronger effect on the results –yet the ICER stayed at what could be considered to be an acceptable level.

Table 7. The results of one-way sensitivity analyses, incremental cost-effectiveness ratio of population-based AAA screening compared with no population-based AAA screening, €/LYG.

The 26 studies identified in the review represent a variety of healthcare settings, periods and methodological approaches. Also the target population varies to some extent in terms of age. Consequently, great care should be taken when extrapolating results from these studies to specific settings.

Overall there seems to be a reasonably uniform body of evidence indicating that population screening for AAA using a single ultrasound investigation entails an ICER of less than approximately 10 000 €. The number may also be considerably lower, even less than 200 € (e.g. {26}).

Those four studies in which the ICER was estimated to be the highest all contain features that make their applicability in other settings questionable in present-day Europe. The Canadian study {38} and one of the UK studies {40} are from the 1990s and hence their results may be outdated. One should also notice that this early UK study reported two different ICERs depending on the aneurysm size {40}. The other UK study is more recent {35}, but its time horizon is only 7 years. Its authors conclude that it compares well with other screening programmes and that they expect its lifetime cost-effectiveness to be highly favourable. The 10-year results of the same study were reported in another paper included in this review and they were in line with the majority results {10}. The authors of the Danish study concluded that AAA screening would be unlikely to be cost-effective {2}. This study has been heavily criticised for its methods {44-46}. Four out of five authors of the Danish study were also authors of the most critical literature review {34}.

Most of the studies that we have referenced above in detail are studies that reported upper and lower limits of the range of findings. Three key studies were not explicitly referenced but belong to the analysis {47–49}.

The four systematic reviews we found were not uniform in their conclusions {34, 41-43}. Our current review, however, contains seven studies that have been published after the time limits of the literature searches in the four reviews.

It should also be noted that the current evidence does not contain justification for excluding women as a target group for AAA screening. The evidence concerning women is less extensive though and would probably benefit from further research.

Analysing the question shows that the main issue is in “organised population” screening (see PICO question). This implies the responsibility of the healthcare system (authority) for a recommendation. In most settings the “standard mode of care” means AAAs are found by accident or at a symptomatic stage. Healthcare providers may counsel individuals at high risk but there is no strong guidance and therefore high variability can be assumed.

• Respect for autonomy: the standard mode of care as well as organised population screening meets this criterion.
• Non-maleficence: the standard mode of care as well as an organised population screening meets this criterion. In an organised programme quality assurance and outcome evaluation should provide a higher degree of fulfilment. The organised programme with a definition of those eligible for screening reduces “waste of resources” for those at low risk. It could harm people outside the target group by reducing access to this preventive care intervention.
• Beneficence: balancing risks and cost with potential benefits can only be done at the national or local level (information on cost is national or local). To balance risks and potential benefits without regard to costs, the first step is to decide whether to look at the risks of ultrasound alone or – in the case of a positive finding – to consider the risks and decision problems of the subsequent chain of diagnostics and potential interventions. This will be done in the domain summary.
• Justice: looking at the healthcare system as an SSGI the dimension of justice gets a low value in the standard mode of care. Organised screening dramatically increases the value of the justice domain.

The AAA screening survey (see current use domain) shows that only Sweden provides organised AAA screening programme. Lithuania describes the situation as an opportunistic one. The description resembles the answer of Spain. In CUR7 the UK NHS is cited as having an organised screening tool. In most countries organised population-based screening would be a new proposal.

Ultrasound examinations of the abdomen are well established in all healthcare systems. The new items therefore would be the

• recommendation (and information) by the “health authority”
• definition of the target group (with an invitation system)
• evaluation of quality and outcome

As proposed in the section on quality assessment tools and criteria for this question a score using the four ethical dimensions should be collected.

The general approach on the EU level has to be put into operation at the local level. This could be done using an interactive participatory approach to HTA.

• Respect for autonomy: the standard mode of care as well as organised population screening meets this criterion.
• Non-maleficence: the standard mode of care as well as organised population screening meets this criterion. In an organised programme quality assurance and outcome evaluation should provide a higher degree of fulfilment. The organised programme with a definition of those eligible for screening reduces “waste of resources” for those at low risk. It could harm people outside the target group by reducing access to this preventive care intervention.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost is local). To balance risks and potential benefits without regard to costs, the first step is to decide, whether to look at the risks of ultrasound alone or – in the case of a positive finding – to consider the risks and decision problems of the subsequent chain of diagnostics and potential interventions. This will be done in the domain summary.
• Justice: Looking at the healthcare system as a SSGI the dimension of justice gets a low value in the standard mode of care. Organised screening dramatically increases the value of the justice domain.

The main challenge in this question is finding a “threshold” of incidence or prevalence for screening in general and for gender-specific screening in particular.

• Respect for autonomy: organised population screening does not threaten autonomy.
• Non-maleficence: organised population screening meets this criterion. The organised programme with a definition of those eligible for screening reduces “waste of resources” for those at low risk. It could harm people outside the target group by reducing access to this preventive care intervention. This problem is particularly relevant if eligibility is linked to gender. Is the difference in incidence high enough to exclude women from this type of screening?
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost is local). To balance of risks and potential benefits without regard to costs, the first step is to decide whether to look at the risks of ultrasound alone or – in the case of a positive finding – to consider the risks and decision problems of the following chain of diagnostics and potential interventions. Gender differences in the overall pattern of diseases and differences in life expectancy are important.
• Justice: Excluding women from screening needs a strong argumentation.

The main problem is whether gender is a suitable criterion for determining eligibility for screening. This judgment should be based on results from the effectiveness and safety domain.

Judgement has to be used with regard to national/local epidemiology.

• • Respect for autonomy: organised population screening does not threaten autonomy. It addresses everyone in the same way using the invitation system. Depending on the framework and site of service provision, accessibility may differ for different patient groups – such as those in rural areas and provision in hospitals. In this question, the rights of healthcare providers to perform services (workload and income) should also be considered.
  • Non-maleficence: organised population screening addresses everyone in the same way using the invitation system.
  • Beneficence: balancing risks and costs with potential benefits can only be done at the local level (information on cost is local). The influence of the regional infrastructure for service provision, in particular, is a key determinant. The framework of the healthcare system should provide the arguments for the organisational decisions.
  • Justice: In this question the domain of justice not only addresses the people eligible for AAA screening but also the service providers. Allocating the service provision to general practice, hospitals or specialised units for ultrasound examinations involves decisions about quality, workload and income.

In general organised population screening should address all those eligible for the procedure equally. But the organisation and allocation of the service provision influences the accessibility and inflicts consequences on healthcare providers. So the framework of the healthcare system, geographical reality and the current state of infrastructure are highly important. Decisions can only be taken on a local level.

For each medical intervention informed consent is necessary. The common quality framework for SSGIs shows the responsibilities of a public authority in this context. So the information materials needed for informed consent should be provided by this authority. They should not only cover information on the ultrasound test but also on subsequent management in case of a positive finding. It should thus be possible to reach an informed decision about the test and about the subsequent management. This includes all activities in the field of quality management and evaluation – with a special focus on data use (data protection rights).

• Respect for autonomy: organised population screening does not threaten autonomy. The issuer of the recommendation has the responsibility to inform potential participants as comprehensively and extensively as possible
• Non-maleficence: information should include the following management and aspects of data use
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost is local). Organisational aspects are important
• Justice: In this question the domain of justice addresses not only the test procedure but also organisational aspects especially in evaluation

The information provided should be as comprehensive and as extensive as possible. The (political) accountability in the field of SSGIs, data protection issues and the local cultural background have the most impact. See SOC5 with regard to positive or negative emotional reactions of screening subjects. Due to differences in local cultural background it can be expected that these reactions will differ.

As already stated the organisational decisions accompanying the implementation of an AAA screening have an impact on the healthcare professionals at least on their workload and income

• Respect for autonomy: organised population screening reduces the autonomy of the individual healthcare professional. The performance of the service provision is standardised and monitored.
• Non-maleficence: standardisation is sometimes seen as destruction of the professional “art”. This was discussed during the scoping. The acceptance of standardisation varies due to cultural differences. Decisions about allocation of services have an impact on income or workload.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). Organisational aspects are important. Screening may bring additional money to the system.
• Justice: In this question the domain of justice addresses the political interests of the healthcare providers. The impact on different groups of providers depends on the type of organisational decision.

As professional autonomy is reduced by standardisation of  organised screening programme, and decisions about the type of organisation have an impact on workload and income, the acceptability of such a programme from the viewpoint of the healthcare providers will depend on the local setting. Early involvement and balancing pros and cons of different organisational settings are important. The interactive, participatory HTA approach (iHTA – see Ethical methodology 100906) should attach considerable weight to the opinions of the experts and the healthcare provider.

Human integrity has to be considered in any “public” intervention. In a healthcare system based on “solidarity” it is expressed in the root documents cited to define the principles of these ethical considerations that some responsibilities are allocated at the system level. Typically they address questions that individuals are not able to answer. This can derive from a different view on discounting the future, the broad public health perspective necessary or the access to data and methods for informing decision making. Just as in medicine where guidelines summarise the clinical evidence because individual medical doctors cannot read one billion publications a year (the expected number of entries in PubMed in 2012), public health policy, with democratic legitimacy, summarises the evidence and the preferences of their population.

So questions of democratic legitimacy and citizen or patient involvement in policy decisions have to be considered. The nine principles of the common quality framework for SSGIs should be followed.

Nevertheless the integrity or freedom of the healthcare professionals is reduced by standardisation of an organised screening programme. The definition of a screening programme, the data acquisition, the quality assurance, monitoring and evaluation challenge professional values and opinions.

• Respect for autonomy: organised population screening is an intervention recommended by “the public” and therefore reduces the autonomy of the individual healthcare professional. The performance of the service provision is standardised and monitored. The autonomy of the individual citizen in cases where a recommendation is made is not at stake.
• Non-maleficence: standardisation is sometimes seen as destruction of the professional “art”. In a pluralistic society a total consensus cannot be achieved. Decisions supported by majorities have to consider the right to abstain for minorities.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). On a societal level organised programmes secure access.
• Justice: In this question the domain of justice addresses the political interests of the healthcare providers. The impact on different groups of providers depends on the type of organisational decision. Organised programmes have the potential to reduce the gaps in access to care caused by lack of education and information.

The integrity of screening subjects is respected as there is no obligation to participate. But by standardisation of healthcare provision the integrity of healthcare providers can be reduced. In a healthcare system based on solidarity a restriction, for the healthcare providers, in their ability to live according their moral convictions, preferences or commitments is to some extent justified. The rules of SSGI should be followed and an inclusive discussion to gain broad acceptance and democratic legitimacy is necessary.

In organised screening the final decision about participation remains at the individual level. The healthcare system and the care provider are responsible only for the best possible information to permit informed decision making or informed consent.

• Respect for autonomy: organised population screening is recommended and provides information to support decision making on the individual level.
• Non-maleficence: effects on other aspects of the healthcare system are important. Sustainability and resource use, in particular, may influence decisions at the system level.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). A societal perspective – looking beyond the healthcare system perspective – is recommended.
• Justice: In this question, the domain of justice requires objective information to compare the different possible ways of investing public money.

The main challenge of (most) political decisions in healthcare is the conflicting goals and values not only in different policy areas but also on different levels within the system. In a pluralistic society such conflicts are normal. Usually the level of clinical medicine “belongs”  to the patient and the clinician. The level of the health system is the domain of “organisations” – the stakeholders (providers, payers, patient groups, industry and so on). The last level deals with the balance of interests between political fields such as education, the labour market, others... and health. It may be attributable to the fact that the issue of AAA screening is a multi-level, multi-stakeholder and diverse interest dilemma. The international dimension should also be taken into account – particularly the previously mentioned open method of coordination of the EU.

So the balancing of the benefits and harms can be done only at the local level because local current use has to be taken into account. The open method of coordination aims to harmonise  healthcare and public health priorities on the EU level.

In this question the dimension of justice is highlighted. So a summary of the previous findings is necessary.

Justice:

• ETH1: Looking at the healthcare system as an SSGI the dimension of justice is given a low value in the standard mode of care. Organised screening dramatically increases the value of the justice domain.
• ETH2: Excluding women from screening needs a strong argument.
• ETH3: In this question the domain of justice not only addresses the people eligible for AAA screening but also the service providers. Allocating the service provision to general practice, hospitals or specialised units for ultrasound examinations involves decisions about quality, workload and income.
• ETH4: In this question the domain of justice not only addresses the test procedure but also organisational aspects especially in evaluation
• ETH5: In this question the domain of justice addresses political interest of the healthcare providers. The impact on different groups of providers depends on the type of organisational decision.
• ETH6: In this question the domain of justice addresses the political interests of the healthcare providers. The impact on different groups of providers depends on the type of organisational decision. Organised programmes are able to reduce the gaps in access to care caused by lack of education and information.
• ETH7: In this question the domain of justice requires objective information to compare different possibilities of investing public money.

Justice addresses restriction to access for citizens by gender or other characteristics, the healthcare system as an SSGI, organisational aspects for providers, evaluation for citizens (data protection), and objective information needed both for informed consent (clinical level) and for system decisions (political level). At the moment a clear rule for prioritising screening procedures is not available, so decisions will follow national or local priorities and values.

The best possible and most objective information to permit informed decision making or informed consent is needed, not only with regard to the ultrasound test but also, in cases where there is a positive test, about the subsequent pathway of care. Information on the subsequent steps should provide both an overview and in depth information on demand.

• Respect for autonomy: organised population screening is a recommendation and provides information to support decision making on the individual level. Endpoints relevant for participants – their preferences and their fears – should be taken from qualitative surveys.
• Non-maleficence: comprehensive information is needed to ameliorate the reduction in quality of life in cases of positive test results.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). A societal perspective – looking beyond the healthcare system perspective – is recommended. The fears and preferences of citizens guide this balancing.
• Justice: In this question the domain of justice addresses mainly the question of citizen involvement in the decision-making process. Expert opinion is also needed, but the leading role stays with patients and citizens.

The result card A0009 “What aspects of the burden of disease are affected by AAA screening?” presents an overview of outcome measures found in the literature. It was not addressed whether these outcomes were chosen by experts or with patient involvement. This should be clarified.

The general approach on the EU level has to be put into operation at the local level. This could be done using an interactive participatory approach to HTA.

• Respect for autonomy: organised population screening is a recommendation and provides information to support decision making on the individual level. Endpoints relevant for participants – their preferences and their fears – should be taken from qualitative surveys.
• Non-maleficence: comprehensive information is needed to ameliorate the reduction in quality of life in cases of positive test results.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). A societal perspective – looking beyond the healthcare system perspective – is recommended. The fears and preferences of citizens are the guidance for this balancing.
• Justice: In this question the domain of justice addresses mainly the question of citizen involvement in the decision process. Expert opinion is also needed, but the leading role stays with patients and citizens.

At the moment a clear rule for prioritising screening procedures is not available. The decision process is mainly driven by scientific organisations of care providers. This expert opinion is based (hopefully) on clinical studies, clinical experience and a broad knowledge of the natural course of the disease. The definition of cut-off values for tests should be based on scientific evidence.

• Respect for autonomy: organised population screening is a recommendation and provides information to support decision making on the individual level. As well as the potential benefits and harms, the uncertainty associated with tests and prognoses also have to be addressed.
• Non-maleficence: comprehensive information is needed to deal with uncertainty.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). Uncertainty is part of every prognosis. So it must be stated that “more is not automatically better” and that is a key point when balancing different scales.
• Justice: In this question the domain of justice addresses potential restrictions deriving from the setting of cut-offs. Accuracy measures determine inclusion or exclusion of individuals or in a rule for prioritizing screening methods for healthy individuals according to age and /or gender need a clear rational.

Decisions about cut-off values need a valid scientific basis. The uncertainty associated with all decisions and prognoses has to be communicated. The degree of uncertainty acceptable in a healthcare system should be made explicit and is the subject of a value judgement.

The general approach on the EU level has to be put into operation at the local level. This could be done using an interactive participatory approach to HTA.

• Respect for autonomy: organised population screening is a recommendation and provides information to support decision making on the individual level. As well as potential benefits and harms, the uncertainty associated with tests and prognoses also have to be addressed.
• Non-maleficence: comprehensive information is needed to deal with uncertainty.
• Beneficence: balancing risks and cost with potential benefits can only be done at the local level (information on cost and organisational issues is local). Uncertainty is part of every prognosis. So it must be stated that “more is not automatically better “and that is a key point when balancing different scales.
• Justice: In this question the domain of justice addresses potential restrictions deriving from the setting of cut-offs. Accuracy measures determine inclusion or exclusion of individuals or in a rule for prioritizing screening methods for groups.

The UK NHS AAA screening programme was started in 2009. Screening is carried out according to the pathway described in Figure 1. Considering medical practice and diagnostic criteria in Europe, it is likely that the screening pathway would be similar in other European countries if AAA screening were implemented.

Figure 1. Abdominal aortic aneurysm screening pathway in UK {1}

NHS guidelines for AAA screening {2} have identified 65-year-old men as the target population for AAA screening based on clinical studies. In the UK all men who are registered with a general practitioner (GP) will receive a personal invitation by mail for screening in the year that they turn 65. Men older than 65 can self-refer into the programme. Invitations are sent and feedback collected by local screening centres. Men who do not attend their screening invitation are either sent a second appointment or asked to contact their local programme to arrange a new date. Men who are invited a second time are sent a further letter saying they will not be invited for further appointments but can contact their local screening programme to self-refer for screening {2}.

Clinic locations are decided locally to ensure that they are accessible. Scanning typically takes place within community healthcare facilities such as community clinics, community hospitals, mobile units and primary care facilities. Men are seen by a health professional (sonographer or screening technician) on arrival at the clinic so that they can receive further information about screening before deciding whether to participate. Men are asked to give their consent to the screening procedure and the use of their personal information. Screeners record two anteroposterior (AP) measurements in centimetres of the maximum abdominal aortic diameter. Results are communicated immediately to all men verbally. Written results are also sent to GPs. Further investigations and treatment depend on the results of the scan:

• Normal result: the aorta has a diameter of less than 3 cm. No aneurysm has been detected. The man is informed of his result and does not require any further scans
• Small aneurysm: the aorta is slightly enlarged and has a diameter of between 3 and 5.4 cm. Men with a small aneurysm do not need to have treatment but are invited to have follow-up scans to monitor the size of the aneurysm.
• If the aorta is between 3 and 4.4cm a follow-up scan is offered in a year
• If the aorta is between 4.5 and 5.4cm a follow-up scan is offered in 3 months

In addition to follow-up scans, men are offered advice on how to reduce their cardiovascular risk factors. The man's GP may also be informed of the need to review medication and reassess blood pressure monitoring,

• Large aneurysm: the aorta has a diameter of over 5.5 cm. Men with a large aneurysm are referred to a consultant vascular surgeon to discuss treatment. Because of screening, surgeons need to be prepared for more elective surgery. A minimum of 20 operations per unit per year is defined as the quality standard. Alternative treatment is endovascular aneurysm repair (EVAR) {2}.

If the aorta cannot be visualised at the clinic a further scan appointment is arranged. If it cannot be visualised at the second appointment then the man is invited for a further scan at a hospital medical imaging unit. He is given guidance recommending minimum food and drink intake in the 4-h period before the proposed scan. Letters are also sent to GPs informing them of non-visualised screening results {2}.

The most significant impact of the screening programme will be on vascular surgery services and theatres. The number of elective operations will increase but there will be a decrease in the number of emergency operations over time {3}. A meta-analysis of four randomised controlled trials of screening older men for AAA was carried out by Lindholt and Norman (2008).  A significant reduction in emergency operations (odds ratio=0.55; 95% confidence interval (CI) 0.39-0.76) and an increase in elective operations (odds ratio=3.27; 95% CI 2.14-5.00) was found {4}.

As systematic population-based AAA screening has not been implemented in most European countries, the possible change after introducing the screening, can be estimated based on the number of elective and emergency operations at present. Mani et al. (2011) have analysed the statistics of AAA repair in several European countries. Table 1 shows the numbers of elective and emergency operations for Denmark, Norway and Sweden.

Table 1. Elective and emergency AAA operations in three European countries {5}

As a result of the increasing number of elective and the decreasing number of emergency operations after the introduction of AAA screening, the workload in involved hospital departments changes. According to The Scottish Government Health Improvement Strategy Division, patients who survive emergency repair of a ruptured AAA are admitted to the intensive treatment unit (ITU) and prolonged ITU admissions are common. After elective open AAA repair most patients in Scotland are admitted to the high dependency unit (HDU) rather than the ITU. After EVAR repair most patients are admitted to an HDU for one day but in some hospitals in Scotland patients are admitted to the vascular surgery ward after the procedure and do not occupy critical care beds {3}.

AAA screening is different from other screening programmes in that the mortality rates associated with treatment are significant: 3-5% for open surgery and 1-3% for EVAR {3}.

Therefore actual mortality is very dependent on the percentage of men that are treated with EVAR repairs. Also other risk factors like age and sex influence mortality. More detailed information about the percentage of EVAR procedures and the percentage of procedures done in women for Denmark, Norway and Sweden are presented in Table 2.

Table 2. Mean age, % of procedures in women and% of EVAR procedures for elective and emergency operations in three European countries (95% CI) {5}

The Vascular Society of Great Britain and Ireland has issued a framework for improving the results of elective AAA repair. The aim of the framework is to halve the mortality rate for elective AAA surgery in the UK (to 3.5%) by 2014 {6}.

Preoperative:

• All patients should undergo standard preoperative assessment and risk scoring to determine their suitability for EVAR.
• Each hospital should have defined pathways for the correction of significant medical risks (cardiology/renal/respiratory) before intervention.
• All patients should be seen by an anaesthetist for reviewing and optimising medication.
• All elective procedures should be reviewed preoperatively by surgeon(s) and radiologist(s) as a team. Ideally, a vascular anaesthetist should also be involved to consider fitness issues that may affect whether open repair or EVAR is offered.

{6}.

Operation:

• Interventions should be undertaken (or supervised) by a consultant surgeon/radiologist/anaesthetist with training and expertise in elective vascular procedures and a routine clinical practice in this specialty.
• Open AAA repair should include the following components: normothermia, cell salvage, rapid infuser, easy access to blood products (within 1 hour) and availability of haemostatic agents including glue.
• EVAR should only be undertaken in a sterile environment of theatre standard, with optimal imaging facilities. A range of rescue stents and devices should be immediately available, together with the expertise to deploy them {6}.

Facilities:

Elective AAA repair should only be undertaken in hospitals where:

• There is a 24/7 on-site vascular on-call rota for vascular emergencies of 1:6 or greater, covered by consultant vascular surgeons and interventional radiologists, to ensure adequate post-operative care.
• There is a 24/7 critical care facility with the capacity to undertake mechanical ventilation and renal support, and with 24-hour on-site anaesthetic cover.
• Wards for dedicated vascular patients should be available with the provision for single sex cubicles or bays.
• At least one endovascular theatre or theatre specification interventional radiology suite is required, preferably with a fixed C arm and a dedicated X-ray table.
• A minimum number of AAA procedures are undertaken. It is recommended that hospitals undertaking fewer than 33 elective AAA interventions per year (100 over 3 years) should not continue to offer these procedures.
• Hospitals should know their AAA mortality and should seek to validate both national audit and Trust data. They should be able to demonstrate safe practice.
• Units with mortality rates for elective repair of 6% or greater should seek external professional review of their care processes.
• An on-site vascular laboratory should be available {6}.

Also the Scottish AAA screening programme foresees a minimum of 20 elective surgeries per unit per year, rising over time to an estimated 32. Patients found to have an AAA should be referred to services that can undertake both open and endovascular repair of aneurysm and that offer advice to each patient on which procedure is most appropriate {3}. All referrals must be assessed for suitability for EVAR. It is estimated that 50% of screen-detected aneurysms in Scotland will be suitable for endovascular repair {3}.

There may be a small impact on Primary Care services from men requesting further information on the screening programme. Information on the screening programme will be circulated to Primary Care prior to roll out. GP practices will be notified of patients who are on surveillance or referred to vascular services {3}.

The difference in patients’ paths is that more men are referred for treatment before AAA rupture (which would send them directly to emergency departments).

UK recommendations for AAA screening organisation {2} were used to describe quality assurance (QA) aspects of systematic population-based AAA screening.

QA systems support commissioners and providers in clinical governance so that core processes are safe and the programme achieves better outcomes. Several activities are involved, including:

• accredited training programmes and continuing professional development of staff
• regular appraisal and refresher training
• standardised calibration of equipment
• monitoring of standardised outcome and performance information with feedback of comparative information to local services from national analysis of screening data, AAA surgery and AAA deaths
• site visits for peer review
• supporting activities for avoidance and management of serious incidents

Ultrasound equipment

• range of standard commercial phantom test objects used, with tests undertaken by an independent Registered Clinical Scientist (Medical Physics)
• periodic testing
• as per acceptance tests, using the same test objects and undertaken by the similarly qualified staff and results reported to the screening office Carried out on an annual basis
• regular testing
• QA checks done at routine maintenance service by equipment manufacturer, carried out at service intervals detailed by the manufacturer
• routine monthly tests using a standard test object carried out locally by the senior sonographer and results reported to the screening office

Other

• questionnaires sent periodically to a sample of randomly selected service users (doctors, practice managers/staff, patients, vascular surgeons) to ask whether any problems arose as a result or in connection with the screening programme
• enquire about any procedural changes that could improve the delivery of the screening programme
• monitor time from referral to outpatient consultation
• referral to vascular unit
• monitor time from referral to surgery {2}

Several strategies to make a screening programme easily accessible are used. The most widely used strategy is to consider the size of the population and the patients’ geographic distribution and to establish local screening centres for better availability. Also mobile screening vans can be used for more distant areas.

UK recommendations for AAA screening organisation {2} were used to give an example of the human resources needed, and their workloads, responsibilities and training needs for systematic population-based AAA screening.

Clinical staff

Director/Clinical Lead (0.2 Whole Time Equivalent (WTE)* per 800,000 population)

A vascular surgeon, responsible to the National Programme Centre, will have responsibility for the overall running of the local programme and for clinical support for their Programme Coordinator, particularly in matters involving patient care. They will also be responsible for making clinical decisions related to screening patients up to the point where a referral has been made.

The primary purpose of this role is to act as the strategic lead for the local AAA screening programme. The Director will oversee the screening programme and take clinical responsibility. The role of the Director is to ensure the successful implementation of the programme and that a high quality service is maintained following implementation.

Lead ultrasound clinician (0.1 wte per 800,000 population)

A radiologist/consultant sonographer/vascular scientist will have special responsibility for quality assurance of staff and the screening process, and responsibility for the screening equipment, staff accreditation and monitoring of clinical performance (including review of scans from screening clinics). This task is often delegated to the clinical skills trainer but this is a local decision. Any quality assurance concerns should be brought to the attention of the director. They will advise on which ultrasound equipment should be purchased and when it needs to be updated or replaced.

Consultants in the vascular units

Vascular surgeons are not employed by the screening programme and are unlikely to participate in the screening programme as such.

In hospital vascular units, the consultant responsible for the care of the patient will be classed as the “responsible” doctor once the referral is received. They should:

• On referral from the local AAA screening programme, ensure that further confirmatory diagnostic image testing is performed and keep records of the findings of this testing
• Assess patients with a view to surgery
• Notify the coordinator of the local screening programme of the outcome of the initial and further outpatient visits and, if indicated, the treatment
• Submit data for audit purposes on an ongoing basis of all AAA surgery.

Screening staff

Clinical skills trainer (senior sonographer/vascular scientist – 0.1 wte per 800,000)

A senior sonographer/vascular scientist is responsible to the director/clinician lead. As the first-line supervisor of the screening technicians, the Clinical Skills Trainer is responsible for staff training and regular review of staff for quality assurance in addition to undertaking routine equipment quality assurance assessments and ensuring regular maintenance of the ultrasound equipment. CSTs also run occasional AAA screening clinics to maintain their skills. They should have extensive experience of training in the workplace. The work within these clinics will include:

• Ensuring that men attending clinics are booked in smoothly and efficiently and are aware of the benefits and risks of the AAA screening programme and give informed consent to the procedures
• Accurately recording aortic sonographic measurements
• Collecting other patient information
• Reporting scan results and their implications to patients both verbally and in writing
• Preparing copies of the results for GPs
• Transferring clinic data to the screening office
• Updating the screening management information technology  (IT) system

As with other clinical staff, more time may be required during initial set-up.

Screening technicians (3 wte per 800,000)

Screening technicians ensure that men attending clinics are booked in smoothly and efficiently and are aware of the benefits and risks of the AAA screening programme and give informed consent to the procedures. They will accurately record sonographic measurements of the aortic diameter, collect other patient information and report scan results and their implications to patients both verbally and in writing. They will also prepare copies of the results for GPs, transfer clinic data to the screening office and update the screening management IT system.

There will be a requirement for all those undertaking the scanning to have attended the nationally approved and accredited training course and fulfilled all the competency requirements of the training. It is recommended that all newly appointed screening technicians have an initial probationary period built into their contract to allow time for training and assessment of competency.

The CST is the first line supervisor of the screening technicians and in turn would be supported by the lead ultrasound clinician.

Nurse practitioner (0.1 wte per full capacity programme – 7,000 scans per year)

The nurse practitioner is involved in assessing and counselling men at specific points in the screening process and giving advice on changes in lifestyle as appropriate. Further referral on to other specialists should be made following discussion with the director of the local screening programme.

Management, administration and technical Staff

Coordinator (1 wte per 800,000 population)

The coordinator is responsible to the director/clinical lead, who delegates the task of the day-to-day running of the screening programme to the coordinator but remains the responsible clinician for patients entered into the screening programme. The primary purpose of the coordinator’s role is to direct the day-to-day operational management of the local programme. They oversee the work of the clerical officer and screening team.

Clerical officer (1 wte per 800,000 population)

The clerical officer is responsible for the administration and is the first point of contact between the screening population and the screening office. The work involves administering and processing patient invitations and appointments, recording information and updating data systems relating to results and patient outcomes and ordering supplies. The clerical officer plays a supporting role to the local AAA screening programme and ensures that members of the public are informed of the benefits of the programme.

Medical physicist (5 days per year for a full capacity programme – 7,000 scans per year)

The purpose of this role is to undertake acceptance of new ultrasound machines and to provide independent, regular quality assessments using sophisticated test objects. This specialist will undertake annual assessments on all the ultrasound machines and probes, assisted by the Senior Practitioner. They will prepare reports for the Director of the local programme.

IT lead

The IT lead supports the coordinator in the timely installation of IT equipment and software, in accordance with the IT checklist issued by the software supplier. The IT lead acts as a single site contact point for IT for the software supplier during implementation. The IT lead is responsible for ensuring the appropriate software for the programme is accessible and they will be available at a high level to troubleshoot when required. They will also facilitate the set-up and process for archiving screening data and back-up.

Governance

The provision of the AAA screening programme involves a number of organisations:

• Strategic Health Authorities
• Primary Care Trusts
• Primary care providers
• Local Screening Programme
• Diagnostic and Treatment Services {2}.
• Whole time equivalent is calculated by assessing the hours the employee is contracted to work and the standard hours for the position (generally 40 hours per week).

UK recommendations for AAA screening organisation {2} were used as an example of informational needs for systematic population-based AAA screening.

Men should be able to make a genuinely informed choice based on an understanding why they are attending for screening, the risks involved and associated with a positive result, and what happens to their records after they are screened {2}.

Implementing a screening programme will require three different kinds of information:

1) For publicity to inform the target population and their relevant others about the screening programme.

The national programme director will be responsible for publicity in relation to the programme and central written resources.

Nationally developed and approved information is available to all local AAA screening programmes. It is the responsibility of the local programme to ensure that information is available to all men and that literature is displayed in appropriate locations.

The invitation leaflet is designed to ensure that men are told what screening can and cannot achieve. This, along with the invitation letter, addresses the need to inform subjects about the use made of personal information for audit.

Posters are available and provided by the national programme centre for display in GP surgeries, other primary care facilities and other suitable public locations identified locally. Information sheets for GPs and other healthcare professionals are also available and provided by the national programme centre.

A website for patients and professionals is administered by the national programme centre {2}.

2) For men participating in the programme that do not need follow-up or operation; men needing follow-up; and men needing operation.

There should be separate leaflets for men who enter the surveillance programme and for those identified with an AAA of 5.5 cm or greater setting out the benefits and risks of AAA surgery. Informed consent must contain information about the risks, benefits and alternatives of treatment {2}. In an ultrasound study most surgeons agreed that mortality should be clearly stated to patients eligible for operation. There were substantial variations in opinion across surgeons regarding what risks should be included and which complication rates to quote {7}. It is agreed that numerical presentation of risks is most suitable for patients, depending on the patient’s preference for being more or less involved in the decision making process {8}.

3) For organisational aspects of screening programme (for staff).

The programme’s internal communication plan is specified in the job descriptions of staff (using IT solutions, mail, telephone, meetings) {2}.

Co-operation, outside the screening programme, needs to be arranged between screening programme staff and surgeons to whom patients with aneurysms larger than 5.5 cm are referred. It is ethically and medically important that all subjects have both a consultation with a surgeon and the surgery itself (when needed) within a reasonable time period. It is also crucial to evaluate the results of the screening programme – by analysing the number of elective procedures and the mortality of those screened and treated. All this needs a working co-operation between screening programme staff and surgeons {2}.

Decentralisation is preferred to make screening more attainable for relatively elderly people (men 65 years old). A Danish hospital-based cohort study of AAA screening showed that distance to screening facility is one of the attendance rate predictors {9}.

Ultrasound machines with digital recording devices are easily portable. Decentralised screening programme is not expected to decrease quality noticeably for several reasons: uniform training of staff, relatively simple and highly accurate diagnostics.

In both European countries, Sweden and the UK, where population-based systematic AAA screening has been implemented it is de-centralised.

Centralisation of treatment should be considered, because a minimum of 20 elective operations per unit per year are recommended to ensure the quality of the operation. This is important because open surgery is associated with a death risk of approximately 5%.

Answered in ORG5.

Revenue costs

Administration costs

One full time administrator is required per centre to organise the screening programme. A consultant vascular surgeon will be attached to each screening centre and will work there for one half day a week. Two central administrators will be required to organise the programme for the whole of England. Specific salaries of staff are country-specific {2}.

From the MASS trial costs of £1.50 for an invitation and £1.47 for a re-invitation are given; these cover clerical staff time, postage and stationery, cost of obtaining patient details, and office space and equipment {10}.

Screening and treatment costs

The number of devices and screening staff depends on the size of population that needs to be screened and other organisational aspects.

Each centre requires financial resources for maintenance of equipment – ultrasound machine, computer and blood pressure machine. Exact costs depend on the devices used (and whether they are mobile or not). The cost of training technicians is to be included. For quality assurance one radiologist per centre and one radiologist for national quality control are needed {2}.

Prices of medical procedures are country-specific.

Table 1. Prices of medical procedures in selected European countries {11}

Capital costs

Capital costs include ultrasound machines and computers, premises for administrative and diagnostic purposes or mobile screening unit (if used). It needs to be taken into account that capital needs to be renewed after fixed time period {2}.

There are also capital costs arising from providing extra beds and intensive care unit beds for post-operative patients.

Every country needs to assess their costs independently using cost-effectiveness analyses or other economic evaluation methods. It is important to take into account that all costs are likely to increase from year to year. Also demographic changes influence all estimates.

Screening programmes are usually financed directly by national or local government. Some countries also apply cost-sharing so that the person to be screened pays part of screening costs (in Sweden men pay a fee for initial ultrasound examination) {11}.

Search in MEDLINE, 11 April 2012, by Kristi Liiv (UTA).

Search terms: screening (abstract), budget impact (all text).

38 hits. 0 about AAA screening. Similarly, no budget impact analyses were found by the ECO domain in cost-effectiveness articles.

One article (Canadian health technology assessment) was found by running the Google search engine with the search phrase “AAA screening impact on healthcare budget”.

Reference: Thanos J, Rebeira M, Shragge W, et al. Vascular Ultrasound Screening for Asymptomatic Abdominal Aortic Aneurysm. Health Policy 2008;4(2):75–83.

Not found.

According to the UK recommendations for AAA screening organisation {2} the most critical points in management are:

• ensure that all eligible men are invited and well informed about the risks and benefits
• ensure that all men needing follow-up or treatment get what they need without delay
• information between screening programme management, GPs, surgeons and patients is moving accurately and without delay
• all information about patient (procedures, treatment result) is saved and available for programme evaluation {2}

IT is used for all monitoring processes.

Systematic screening requires call and recall information and the capture and management of ultrasound images. In the UK the software solution Screening Management and Referral Tracking (SMaRT) system is used.

The software system should have following functions:

• identification and collation of screening cohort
• management of administration, screening and referral process
• recording of AAA surgery and outcomes {2}

A national screening programme gives criteria based on risk information about who should receive screening invitations.

The most important and widely used criterion is age. Abdominal aortic aneurysms (AAAs) are uncommon in people under the age of 60 {12}. In the UK 65-year-old men are invited (because of their elevated risk of AAA rupture). Older men can come for screening by self-referral. Information about the men and their age can be obtained from any national database (population register, GP lists, health insurance database) {2}.

In the UK individuals are excluded from the programme if:

• they have previously been diagnosed with an AAA
• they have previously undergone surgery for AAA repair
• on advice from their GP related to other health concerns
• they have requested that they are permanently removed from the AAA screening programme
• they have already had a scan through the AAA screening programme and the aorta was within normal limits
• they have made an informed choice that they do not wish to be invited for screening {2}

In the UK men and women of any age with a strong family history can be scanned under existing procedures following referral by their GP to a medical imaging department {2}.

In Lithuania 65-year-old men with high blood pressure identified during a doctor’s visit are offered the possibility of screening although this is generally defined as opportunistic not systematic population-based screening. In Sweden 65-year- old men are invited and screening of siblings is not included but vascular surgeons inform patients with AAA that siblings over 50 years old should undergo ultrasound evaluation for possible AAA {11}.

No direct evidence exists of complete acceptability to health professionals and the public but acceptance is high and the introduction of screening in the UK would be supported by the majority of vascular surgeons, provided that sufficient resources were made available to carry out screening effectively and efficiently. In addition questionnaires asking about acceptability were sent to participants and GPs. The majority of responses were positive {13}.

In the MASS trial no significant changes in quality of life were detected throughout the screening process. In addition, questionnaires asking about acceptability were sent to participants and GPs. The majority of responses were positive {13}.

In Sweden the attendance rate for screening is 80-85% of those invited {11}.

A Danish cohort study showed an attendance rate of 76% after postal invitation to AAA screening {9}.

No answer found.