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}.