Systematic Review: Repair of Unruptured Abdominal Aortic Aneurysm

BACKGROUND: Recent recommendations to screen for abdominal aortic aneurysm (AAA) in high-risk populations and the rapidly increasing use of endovascular repair have led to increased interest in evaluating the effectiveness of treatment options for patients with AAA. PURPOSE: To compare the effectiveness of treatment options, including active surveillance, open repair, and endovascular repair, for unruptured AAAs. DATA SOURCES: The authors searched MEDLINE, the Cochrane Library, and www.ClinicalTrials.gov through December 2006 with no language restrictions, searched reference lists, and queried experts and study authors. STUDY SELECTION: Randomized trials that compared open or endovascular AAA repair with another treatment strategy and published clinical outcomes. DATA EXTRACTION: Data were extracted onto standardized, piloted forms and were confirmed. DATA SYNTHESIS: Two trials compared open repair with surveillance for small AAAs (n = 2226). Repair did not improve all-cause mortality (relative risk, 1.01 [95% CI, 0.77 to 1.32]) or AAA-related mortality (relative risk, 0.78 [CI, 0.56 to 1.10]). Four trials compared open repair with endovascular repair (n = 1532). Endovascular repair reduced 30-day mortality (relative risk, 0.33 [CI, 0.17 to 0.64]) but not mid-term (up to 4 years) mortality (relative risk, 0.95 [CI, 0.76 to 1.19]). One trial compared endovascular repair with observation in 338 patients who were unfit for open repair. Endovascular repair did not reduce all-cause mortality or AAA-related mortality, but high crossover and procedural mortality rates complicate interpretation of results. LIMITATIONS: Few trials have been published. Those published were of small to moderate size and were not U.S. trials of endovascular repair. CONCLUSIONS: Repairing AAAs smaller than 5.5 cm has not been shown to improve survival. Endovascular repair is associated with lower operative mortality than open repair, similar mid-term mortality, and unknown long-term mortality and has not been shown to improve survival in patients unfit for open repair. Long-term trial data comparing endovascular repair with open repair are needed, as is another trial comparing endovascular repair with observation in high-risk patients.