National outcomes in acute aortic dissection: Influence of surgeon and institutional volume on operative mortality

Background: Despite clinical and technical advances, acute aortic dissection carries high operative mortality. This study was designed to establish whether this is influenced by institution and surgeon volume. Methods: Outcomes of 5,184 patients (mean age, 60.3 years; 65.9% male) diagnosed with acute aortic dissection from the Nationwide Inpatient Sample from 2003 to 2008 were analyzed with risk-adjustment for preoperative comorbidity using multivariate logistic regression analysis. Results: Overall operative mortality was 21.6%, with similar preoperative patient risk profile across institutions and individual surgeons. A strong inverse relationship was observed between operative mortality and both institution and surgeon volume: surgeons who averaged less than 1 aortic dissection repair annually had a mean operative mortality of 27.5%, compared with 17.0% for those averaging 5 or more annually (odds ratio, 1.78; 95% confidence interval, 1.39 to 2.29; p < 0.001). This was similar to the relationship seen between institution volume and mortality: operative mortality was 27.4% in institutions performing 3 or fewer acute aortic dissections a year, compared with 16.4% in those performing more than 13 annually (p < 0.001). Nationally, operative mortality decreased steadily from 23% in 1998-2000 to 19% in 2005-2008, with no significant decrease in patient risk profile. Conclusions: Patients undergoing emergency repair of acute aortic dissection by lower-volume surgeons and centers have approximately double the risk-adjusted mortality of patients undergoing repair by the highest volume care providers. Routine involvement, whenever feasible, of teams experienced in acute aortic dissection repair may be a strategy to reduce operative mortality and major morbidity.