title: The first 150 endovascular AAA repairs at a single institution: how steep is the learning curve?
abstract: OBJECTIVE
  To determine whether increasing experience with endovascular abdominal aortic aneurysm (AAA) repair in a single institution will result in improved outcome.
  
  
  METHODS
  A retrospective review was undertaken of 150 consecutive cases of endovascular AAA repairs performed using the AneuRx device between October 1996 and April 2000 in a university-based medical center. The population was divided into early and late groups of 75 patients each. Endpoints included technical success; complications; early (< or =30-day) morbidity, mortality and rupture; endoleak at discharge and at 1 month; early secondary intervention; proximal neck and iliac tortuosity; extender cuff placement; femoral reconstructions beyond primary repair; total fluoroscopy time; and contrast load.
  
  
  RESULTS
  Baseline patient and aneurysm characteristics were similar between the 2 groups. Technical success was 98.7%; 2 cases were converted intraprocedurally owing to difficult iliac access (early group) and a severely angulated proximal neck (late group). There was a tendency toward more frequent use of intraoperative proximal extender cuffs in the early group (12% versus 4% in the late group, p=0.13). Femoral reconstructions were more frequent in the early group (36% versus 19%, p<0.025). While total contrast volume was similar (111 +/- 56 versus 105 +/- 45 mL, p=NS), total fluoroscopy time was significantly reduced (p<0.05) between the early and late groups.
  
  
  CONCLUSIONS
  With attention to detail and careful patient selection, successful endovascular AAA repair can be achieved with very few conversions and low perioperative mortality even during the center's early experience. Evidence indicates, however, that a learning curve definitely exists, as shown by fewer access site problems, more accurate device deployments, and decreased fluoroscopy times as proficiency is attained.
authors.affiliation: Division of Vascular Surgery, Stanford University Medical Center, 300 Pasteur Drive H-3638, Stanford, CA 94305-5642, USA.
authors.forename: W Anthony
authors.initials: WA
authors.lastname: Lee
authors.forename: Yehuda G
authors.initials: YG
authors.lastname: Wolf
authors.forename: Bradley B
authors.initials: BB
authors.lastname: Hill
authors.forename: Paul
authors.initials: P
authors.lastname: Cipriano
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Fogarty
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Zarins
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000601:surgery*; D019917:Blood Vessel Prosthesis Implantation; D002983:Clinical Competence; D005260:Female; D006801:Humans; D007431:Intraoperative Complications; D008297:Male; D011183:Postoperative Complications; D012086:Reoperation; D012189:Retrospective Studies; D015607:Stents; D016896:Treatment Outcome