title: Learning curve analysis of thoracic endovascular aortic repair in relation to credentialing guidelines.
abstract: OBJECTIVE
  Recently, practice guideline documents have recommended the completion of different levels of interventional experience and 5 or 10 thoracic endovascular aortic cases prior to surgeon credentialing. This study's purpose was to determine whether these requirements are valid by reviewing three surgeons' learning curves with thoracic aortic endovascular repairs.
  
  
  METHODS
  Between 1998 and 2006, 67 patients underwent emergent or elective endovascular repair of thoracic aortic pathologies by one of three vascular surgeons with extensive experience with catheter manipulation and abdominal aortic endografts. Following standard retrospective review, each surgeon's learning curve was analyzed using the cumulative sum failure method with a target success rate of 95% derived from the literature. The main outcome variable was primary technical success.
  
  
  RESULTS
  These 67 patients presented with several pathologies including elective (n = 31) and ruptured (n = 11) thoracic aortic aneurysms, acute dissections or aortic ulcers (n = 10), and acute blunt thoracic aortic trauma (n = 15). The mean age was 65 (range: 20 to 90) and the early (30 day) mortality rate was 19.4% in urgent cases (n = 36) and 0% in elective cases (n = 31). Paraplegia occurred in two patients (3%). Primary technical success was achieved in 62 cases (92.5%) and did not differ between surgeons (92.6%, 91.3%, 94.1%, respectively; P = .9). Each surgeon's cases were plotted sequentially and the resulting learning curves were similar. Although acceptable outcomes were obtained throughout the study period, improved results, compared with the target success rate, were not achieved until each surgeon treated 5 to 10 patients.
  
  
  CONCLUSIONS
  This study supports the case volume requirements of the Society for Vascular Surgery credentialing guidelines, which also requires extensive catheter and guidewire experience. With this background in catheter manipulation and endovascular abdominal aortic repair, surgeons can achieve optimal outcomes with thoracic aortic lesions following 5 to 10 cases.
authors.affiliation: Division of Vascular Surgery, London Health Sciences Centre and the University of Western Ontario, London, Ontario, Canada. Tom.Forbes@lhsc.on.ca
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Forbes
authors.forename: Michael W A
authors.initials: MW
authors.lastname: Chu
authors.forename: D Kirk
authors.initials: DK
authors.lastname: Lawlor
authors.forename: Guy
authors.initials: G
authors.lastname: DeRose
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Harris
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001013:Aorta, Thoracic / Q000601:surgery*; D001018:Aortic Diseases / Q000601:surgery*; D002983:Clinical Competence; D003406:Credentialing; D005260:Female; D017408:Guidelines as Topic; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013043:Specialties, Surgical / Q000193:education*; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000009:adverse effects / Q000193:education*