Abdominal aortic aneurysm (AAA): cost-effectiveness of screening, surveillance of intermediate-sized AAA, and management of symptomatic AAA

Abstract

Physicians must make decisions about screening patients for abdominal aortic aneurysms (AAAs), monitoring or referring for surgery patients with AAAs of various sizes, and assessing patients with symptoms that may be related to AAAs. This review article analyzes the evidence for each scenario. The effectiveness and cost-effectiveness of screening for AAA is based on results from four randomized controlled trials. A cost-effectiveness analysis using a Markov model showed that ultrasound screening of white men beginning at age 65 is both effective and cost-effective in preventing AAA-related death. Such screening would have a small but real impact over a 20-year period in these men. For patients with a known AAA-which is often detected incidentally-the evidence clearly suggests periodic ultrasound surveillance for those with small AAAs (3.0-3.9 cm in diameter) and elective surgical repair for those with large AAAs (>or=5.5 cm). Two recent randomized controlled trials have shown that early surgical repair confers no survival benefit compared with periodic surveillance for patients with intermediate-sized AAAs (4.0-5.5 cm in diameter), so those patients can also be monitored. Some centers choose to increase the frequency of monitoring to every 3 to 6 months when the AAA reaches 5.0 cm. Factors to consider in assessing symptomatic patients include the high risk of life-threatening conditions, the potential increased risk of death or poor outcome with delay in diagnosis, the limitations of ultrasound in identifying whether symptoms are due to known or suspected AAA, and the timely availability of computed tomography or other imaging tests. If available, computed tomography is preferred in patients with recent or severe symptoms, since it is better at detecting retroperitoneal hemorrhage and other complications and in providing preoperative definition of the anatomy.

Figure 1

Outcomes of ultrasound screening for AAA vs usual care after 20 years for a cohort of 100,000 persons in a decision analysis model.

Figure 2

AAA-related outcomes of ultrasound screening for AAA vs usual care after 20 years for a cohort of 100,000 persons in a decision model. Excludes persons without AAA and deaths due to non-AAA-related causes.

Figure 3

Cumulative survival according to treatment group in the Aneurysm Detection and Management (ADAM) study. Reprinted with permission from reference 21. Copyright © 2002 Massachusetts Medical Society. All rights reserved.

Figure 4

Kaplan-Meier estimates of overall survival according to treatment-group assignment in the UK Small Aneurysm Trial. P = 0.05 by the log-rank test. I represent the 95% confidence intervals for the point estimates. Reprinted with permission from reference . Copyright © 2002 Massachusetts Medical Society. All rights reserved.