Surgeon Volume and Established Hospital Perioperative Mortality Rate Together Predict Superior Outcomes After Open AAA Repair.

Abstract

BACKGROUND\nIn 2018, the SVS published hospital volume guidelines for elective open abdominal aortic aneurysm (AAA) repair, recommending elective open surgical repair for AAA be performed at centers with an annual volume of at least 10 open aortic operations of any type and a documented perioperative mortality of 5% or less. Recent work suggests a yearly surgeon volume of ≥7 open aortic cases for improved outcomes. The objective of this study is to assess the importance of hospital volume and surgeon volume at these cut points in predicting 1-year mortality after OSR for AAA.\n\n\nMETHODS\nWe evaluated patients undergoing elective open AAA repair using The New York Statewide Planning and Research Cooperative System database from 2003 to 2014. The effect of the SVS guidelines on postoperative mortality and complications was evaluated. Confounding between hospital and surgeon volume was identified using mixed-effects multivariate cox proportional hazards analysis. The effect of interactions between hospital volume, established hospital perioperative survival, and surgeon volume on post-operative outcomes was investigated.\n\n\nRESULTS\nThe cohort consisted of 7,594 elective open AAA repairs performed by 542 surgeons in 137 hospitals over the 12 years. Analysis of the 2018 guidelines using the SPARCS database resulted in 1-year and 30-day mortality rates of 9.2% (8.3-10.1) and 3.5% (2.9-4.1) for centers that were within the guidelines and 13.6% (12.5-14.7) and 6.9% (6.1-7.8) for those that were outside the guidelines, respectively (both p<0.001). The multivariate survival analysis returned hazard ratios for surgeon volume ≥7, hospital volume ≥10, and hospital 3-year perioperative mortality of ≤5% of 0.80 (95% CI: 0.70-0.93, p=0.003), 0.91 (0.77-1.08, p=0.298), and 0.72 (0.62-0.82, p<0.001), respectively. Additionally, procedures performed by surgeons with a yearly average volume of open aortic operations ≥7 and at hospitals with an established elective open AAA repair perioperative mortality rate ≤5% showed improved 1-year (p<0.001, 33.2% relative risk reduction) and 30-day (p=0.001) all-cause survival and improved postoperative complication rates.\n\n\nCONCLUSIONS\nThese data demonstrate centers that meet the SVS AAA volume guidelines are associated with improved 1-year and 30-day all-cause survival; however, are confounded by surgeon volume. Surgeon open aortic volume ≥7 and established hospital perioperative mortality of ≤5% each independently predict 1-year survival after open AAA repair, while hospital volume is less important. Surgeons with an annual volume of at least 7 open aortic operations of any type should perform elective open AAA repair at centers with a documented perioperative mortality of 5% or less.