The impact of surgeon and hospital procedural volume on outcomes after aortic root replacement in the United States.

OBJECTIVE: Surgeon procedural volume for complex cardiac procedures have become important quality metrics. The objective is to determine the association of surgeon and hospital case volume on patient outcomes after an aortic root replacement for aortic root aneurysms. METHODS: From 2009 to 2014, 4629 Medicare patients underwent an aortic root replacement for a root aneurysm. Procedures were performed by 1276 surgeons at 718 hospitals. Patients with endocarditis, aortic rupture, or Type-A dissection were excluded. Procedural volume was defined as mean number of cases performed each year during the study period. The impact of hospital and surgeon volume on adjusted 30-day mortality was analyzed as a continuous variable using adjusted logistic regression with cubic splines. RESULTS: After an aortic root replacement, we observed a nonlinear reduction in the adjusted odds ratio for 30-day mortality as surgeon and hospital volume increased. Surgeons that performed approximately five cases/year and hospitals that completed approximately five cases/year had the greatest reduction in the odds of perioperative death. Patients treated at high-volume hospitals (≥4.5 cases/year) had a lower risk for 30-day postoperative stroke (hazard ratio [HR] = 0.51, p = .008), myocardial infarction (HR = 0.49, p = .016), hemodialysis (HR = 0.44, p = .005), and reoperation (HR = 0.48, p = .003). Additionally, patients treated with high-volume surgeons (≥9 cases/year) had lower risk for stroke (HR = 0.65, p = .005), hemodialysis (HR = 0.65, p = .03), sepsis (HR = 0.62, p = .03), and reoperation (HR = 0.67, p = .004). CONCLUSION: Among Medicare patients undergoing an aortic root replacement, there is a strong inverse relationship between annualized surgeon and hospital case volume and postoperative outcomes. Procedural volume is an important quality metric for this high-risk procedure.