Higher Institutional Volume Reduces Mortality in Reoperative Proximal Thoracic Aortic Surgery

Objective This study aims to determine the impact of institutional volume on mortality in reoperative proximal thoracic aortic surgery patients using national outcomes data. Methods The Nationwide Inpatient Sample was queried from 1998 to 2011 for patients with diagnoses of thoracic aneurysm and/or dissection who underwent open mediastinal repair. A total of 103,860 patients were identified. A total of 1,430 patients had prior cardiac surgery. Patients were further stratified into groups by institutional aortic volume: low (<12 cases/year), medium (12–39 cases/year), and high (40+ cases/year) volume. Multivariable risk-adjusted analysis accounting for emergent status and aortic dissection among other factors was performed to determine the impact of institutional volume on mortality. Results Overall mortality was 12% in the reoperative population. When the redo cohort was divided into tertiles, high-volume group had a 5% operative mortality compared with 9 and 15% for the medium- and low-volume groups, respectively. Multivariable analysis revealed that patients operated on at low- (odds ratio [OR] = 5.0, 95% confidence interval [CI]: 2.6–9.6, p < 0.001) and medium-volume centers (OR = 2.1, 95% CI: 1.1–4.2, p = 0.03) had higher odds of mortality when compared with patients operated on at high-volume centers. Conclusions High-volume aortic centers can significantly reduce mortality for reoperative aortic surgery, compared with lower volume institutions.