title: Surgeon specialty and provider volumes are related to outcome of intact abdominal aortic aneurysm repair in the United States.
abstract: OBJECTIVE
  This study was undertaken to determine the relative importance of surgeon specialty, hospital volume, and surgeon volume on outcome after abdominal aortic aneurysm (AAA) repair.
  
  
  METHODS
  Data were reviewed for 3912 patients undergoing AAA repair in the Nationwide Inpatient Sample during 1997. In-hospital mortality was compared between high-volume hospitals and low-volume hospitals and between high-volume surgeons and low-volume surgeons. High-volume hospitals performed more than 35 AAA repairs per year, and high-volume surgeons performed more than 10 AAA repairs per year. Vascular, cardiac, and general surgery specialization was identified by analysis of other procedures performed by each surgeon.
  
  
  RESULTS
  Overall, AAA repair mortality was 4.2%, and was lower at high-volume hospitals (3.0%) than at low-volume hospitals (5.5%) (P <.001). Lowest mortality was associated with operations performed by vascular surgeons (2.2%) compared with cardiac surgeons (4.0%) and general surgeons (5.5%) (P <.001). Mortality rates were also lower for high-volume hospitals (2.5%) compared with low-volume hospitals (5.6%) (P <.001). In a risk-adjusted analysis, high-volume hospital, vascular surgery specialty, and high-volume surgeon were all independently associated with lower risk of in-hospital mortality. In this analysis, risk reduction was 30% for high-volume hospitals (95% confidence interval [CI], 2%-51%; P <.05) and 40% for surgery by a high-volume surgeon (95% CI, 12%-60%; P =.01). AAA repair by general surgeons compared with vascular surgeons was associated with 76% greater risk for death (95% CI, 10%-190%; P =.02). No significant difference in mortality was found between cardiac and vascular surgeons.
  
  
  CONCLUSIONS
  High surgeon volume and hospital volume of AAA repair were both associated with lower mortality compared with low-volume providers. Increased specialization in vascular surgery was associated with markedly decreased mortality independent of AAA repair volume. Health policy in support of selective referral for AAA repair should consider surgical specialization in addition to provider volume thresholds.
authors.affiliation: Section of Vascular Surgery, Department of Surgery, University of Michigan Medical Center, 1500 E. Medical Center Drive, Ann Arbor, MI 48109, USA.
authors.forename: Justin B
authors.initials: JB
authors.lastname: Dimick
authors.forename: John A
authors.initials: JA
authors.lastname: Cowan
authors.forename: James C
authors.initials: JC
authors.lastname: Stanley
authors.forename: Peter K
authors.initials: PK
authors.lastname: Henke
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Pronovost
authors.forename: Gilbert R
authors.initials: GR
authors.lastname: Upchurch
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000401:mortality / Q000601:surgery*; D005260:Female; D017052:Hospital Mortality; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D017063:Outcome Assessment, Health Care; D013043:Specialties, Surgical / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology