title: Immediate open repair vs surveillance in patients with small abdominal aortic aneurysms: survival differences by aneurysm size.
abstract: OBJECTIVE
  To assess whether survival differences exist between patients undergoing immediate open repair vs surveillance with selective repair for 4.0- to 5.4-cm abdominal aortic aneurysms (AAAs) and whether these differences vary by diameter, within sexes, or overall.
  
  
  METHODS
  The study cohort included 2226 patients randomized to immediate repair or surveillance for the UK Small Aneurysm Trial (September 1, 1991, through July 31, 1998; follow-up, 2.6-6.9 years) or the Aneurysm Detection and Management trial (August 1, 1992, through July 31, 2000; follow-up, 3.5-8.0 years). Survival differences were assessed with proportional hazard models, adjusted for a comprehensive array of clinical and nonclinical risk factors. Interaction between treatment and AAA size was added to the model to assess whether the effect of immediate open repair vs surveillance varied by AAA size.
  
  
  RESULTS
  The adjusted analysis revealed no statistically significant survival difference between immediate open repair and surveillance patients (hazard ratio [HR], 0.99; 95% CI, 0.83-1.18; mean follow-up time, 1921 days for both study groups). This lack of treatment effect persisted when men (HR, 1.01; 95% CI, 0.84-1.21) and women (HR, 0.96; 95% CI, 0.49-1.86) were examined separately and did not vary by AAA size (P=.39 for the entire cohort and P=.24 for women).
  
  
  CONCLUSIONS
  Immediate open repair offered no significant survival benefit, even in patients with the largest AAAs and highest risk of rupture. Because recent trials failed to find a survival benefit of immediate endovascular repair over surveillance for small asymptomatic AAAs, our findings suggest that the gray area of first-line management for these patients should be resolved in favor of surveillance.
authors.affiliation: Institute for Health Care Research and Improvement, Baylor Health Care System, Dallas, TX 76206, USA. giovanfi@baylorhealth.edu
authors.forename: Giovanni
authors.initials: G
authors.lastname: Filardo
authors.forename: Frank A
authors.initials: FA
authors.lastname: Lederle
authors.forename: David J
authors.initials: DJ
authors.lastname: Ballard
authors.forename: Cody
authors.initials: C
authors.lastname: Hamilton
authors.forename: Briget
authors.initials: B
authors.lastname: da Graca
authors.forename: Jeph
authors.initials: J
authors.lastname: Herrin
authors.forename: Jessica
authors.initials: J
authors.lastname: Harbor
authors.forename: Julie B
authors.initials: JB
authors.lastname: Vanbuskirk
authors.forename: Gary R
authors.initials: GR
authors.lastname: Johnson
authors.forename: Janet T
authors.initials: JT
authors.lastname: Powell
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality / Q000473:pathology / Q000601:surgery*; D001019:Aortic Rupture / Q000401:mortality / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors; D012737:Sex Factors; D016019:Survival Analysis; D057832:Watchful Waiting
keywords: AAA; ADAM; Aneurysm Detection and Management; CAESAR; Comparison of Surveillance versus Aortic Endografting for Small Aneurysm Repair; EVAR; HR; PIVOTAL; Positive Impact of Endovascular Options for Treating Aneurysms Early; UKSAT; United Kingdom Small Aneurysm Trial; abdominal aortic aneurysm; endovascular aneurysm repair; hazard ratio