Surgeon and center volume influence on outcomes after arterial switch operation: analysis of the STS Congenital Heart Surgery Database.

BACKGROUND: The relative impact of center volume and of surgeon volume on early outcomes after the arterial switch operation (ASO) is incompletely understood.
METHODS: Neonates in the Society of Thoracic Surgeons Congenital Heart Surgery Database (2005-2012) undergoing ASO for transposition of the great arteries were included in the analysis. Multivariable logistic regression with adjustment for patient factors and ventricular septal defect closure was used to evaluate relationships between annual center and surgeon volume and a composite end point (in-hospital mortality or major complications).
RESULTS: The study included 2,357 patients (84 centers, 155 surgeons). Median annual ASO center volume was 4 (range, 1 to 18). Median annual surgeon volume was 2 (range, 0.1 to 11). In-hospital mortality was 3.4%; 14.7% had major morbidity and 15.5% met the composite end point. Analyzed individually, lower center and surgeon volumes were each associated with the composite end point (odds ratios for centers with 2 versus 10 cases/y, 1.92; 95% confidence interval, 1.23 to 2.99); odds ratios for surgeons with 1 versus 6 cases/y, 2.16; 95% confidence interval, 1.42 to 3.26). When analyzed together, the addition of surgeon volume to the center volume models attenuated but did not completely mitigate the association of center volume with outcome (relative attenuation of odds ratio = 31%). Addition of center volume to surgeon volume models attenuated the association of surgeon volume with outcome to a lesser degree (relative attenuation of odds ratio = 11%).
CONCLUSIONS: Center and surgeon volume each influence early outcomes after ASO; however, surgeon volume appears to play a more prominent role. Surgeon and center ASO volume should be considered in the context of initiatives to improve outcomes from ASO for transposition of the great arteries.