Treatment of the AAA is dictated by both aneurism size and symptomatology. In an asymptomatic patient, it is imperative to evaluate the individual’s rupture risk, operative risk, and life expectancy. Currently, the best predictor of rupture is aneurysm diameter. Randomized control trials have demonstrated the safety of ultrasound surveillance until AAA diameter exceeds 5.5 cm, and for the majority of patients this is the appropriate course. The United Kingdom Small Aneurysm Trial (UKSAT) and the Aneurysm Detection and Management (ADAM) trial both demonstrated no benefit to early surgery for small 4.0- to 5.5-cm aneurysms. Although the annual rupture risk under surveillance was 1.0% (UKSAT) and 0.6% (ADAM), it was less than the risk of operative mortality in the early surgical groups (5.6% for UKSAT and 2.2% for ADAM). In the UKSAT, fatal rupture occurred in 5% of men and 14% of women undergoing surveillance, suggesting that a lower threshold in women may be appropriate.

The decision to treat must be individualized, as there are other factors that increase rupture risk independent of aneurysm diameter. Rupture risk is increased by female gender, smoking status, rapid expansion (>1 cm/year), hypertension, chronic obstructive pulmonary disease (COPD), family history, eccentric shape, and onset of symptoms or tenderness to palpation of the aorta. Operative risk and life expectancy must also be considered.

Patients with AAA are elderly and most carry significant comorbidities, which put them at increased risk for complications, including myocardial infarction, bleeding, cerebrovascular accidents, and pulmonary complications. Blankensteijn found that mean operative mortality was 8% and 7.4% in population-based prospective and retrospective studies, respectively, whereas for hospital-based studies it was only 3.8%. Others have reported rates for elective repair of 5% (review by Hallin), 5.6% (UKSAT trial), and 5.3% (Medicare data). The operative mortality for open surgical repair has remained stable since 1980s. However, individual comorbid conditions have been identified as independent predictors for operative mortality, with renal failure, heart failure, and older age being the strongest predictors (Table 2). Standard preoperative evaluation should include an electrocardiogram (ECG), complete blood counts, coagulation panel, chemistries including liver and renal function, and a chest X-ray. According to individual risk factors, evaluation may include a cardiac stress testing and pulmonary function testing with arterial blood gases. Smoking cessation decreases the rate of pulmonary complications. Patients with suprarenal and type IV aortic aneurysms are understandably at a
higher risk than patients with infrarenal aneurysms due to visceral ischemia and increased alterations in cardiovascular physiology. Several risk assessment models are available to predict operative mortality after AAA repair (see Giles et al.).

The primary goal of AAA repair is to prolong life; therefore, the patient’s life expectancy must be considered and discussed with the patient before recommending repair. It is not surprising that the same comorbid conditions that increase the patient’s operative risk also shorten life expectancy. However, patients with short life expectancy may benefit if the risk of rupture is exceedingly high. Patients with AAA have been found to have a decreased life expectancy compared with age- and sex-matched controls. Predictors of late death after successful AAA repair include age, gender, continued smoking, renal, pulmonary, and cardiac disease. Table 3 shows US census data from 1998 that have been adjusted to reflect the life expectancy of an average patient surviving elective AAA repair.

Endovascular aneurysm repair (EVAR) has been associated with decreased perioperative morbidity, mortality, and hospital length of stay, making it a more appealing option for patients who were considered high risk for open repair. Randomized control trials, such as Dutch randomised endovascular aneurysm repair (DREAM), EVAR-1, and more recently open versus endovascular repair (OVER), have demonstrated a lower perioperative morbidity and mortality with EVAR compared with open repair. This perioperative advantage persists as a decrease in late aneurysm-related deaths although there was no significant difference in overall survival at 2 and 4 years. These findings of perioperative mortality and morbidity advantage with EVAR as well as similar late survival were confirmed in US Medicare patients. AAA-related reintervention is more likely after EVAR than open repair due to endoleak, migration, kinking, or thrombosis. The majority of these reinterventions are minor and can be performed as a minimally invasive procedure although occasionally conversion to open repair is required. Late rupture while rare after both EVAR and open repair is more common after EVAR. Lifelong surveillance is therefore required after endovascular repair. However, complications of open surgical repair requiring reintervention, including anastomotic pseudoaneurysm and hemorrhage, graft-enteric fistula, colon ischemia, graft thrombosis, and infection have also been reported and are not insignificant. Additionally, complications of laparotomy that are not graft related, such as abdominal wall hernia and bowel obstruction, are seen more commonly after open repair and may offset the increased AAA-related reinterventions associated with EVAR.