title: Systematic review: repair of unruptured abdominal aortic aneurysm.
abstract: 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.
  
  
  OBJECTIVE
  To compare the effectiveness of treatment options, including active surveillance, open repair, and endovascular repair, for unruptured AAAs.
  
  
  METHODS
  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.
  
  
  METHODS
  Randomized trials that compared open or endovascular AAA repair with another treatment strategy and published clinical outcomes.
  
  
  METHODS
  Data were extracted onto standardized, piloted forms and were confirmed.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Veterans Affairs Medical Center and University of Minnesota School of Public Health, Minneapolis, Minnesota 55417, USA.
authors.forename: Frank A
authors.initials: FA
authors.lastname: Lederle
authors.forename: Robert L
authors.initials: RL
authors.lastname: Kane
authors.forename: Roderick
authors.initials: R
authors.lastname: MacDonald
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Wilt
mesh_terms: D017544:Aortic Aneurysm, Abdominal / Q000401:mortality / Q000601:surgery*; D001019:Aortic Rupture; D002423:Cause of Death; D004724:Endoscopy; D006801:Humans; D013997:Time Factors; D016896:Treatment Outcome