Single- Versus Multicenter Surgeons' Risk-Adjusted Coronary Artery Bypass Graft Procedural Outcomes

Since 2010, 460+ hospital mergers have occurred in the United States, rerouting historical coronary artery bypass graft (CABG) referral patterns. The goals of this study were: (1) to compare risk-adjusted CABG outcomes between single-center versus multicenter surgeons; and (2) for multicenter surgeons, to evaluate the risk-adjusted outcomes between their home (primary) versus satellite (secondary) hospitals.

Using The Society of Thoracic Surgeons Adult Cardiac Surgery Database, nonemergent, first-time CABG procedures (n = 543,403) performed in the US between 2011 and 2014 were extracted across 1,120 centers and for 2,676 surgeons. Surgeons were classified as multicenter if they performed operations at two separate hospitals for ≥ 2 consecutive quarters; their home hospital was identified as their highest volume center. Observed-to-expected outcome ratios were reported using approved multivariable risk models for 30-day operative mortality and major morbidity.

Of 2,676 cardiac surgeons, 668 (25.0%) operated at multiple centers. The observed-to-expected mortality ratios were 1.06 (95% confidence interval [CI], 1.01 to 1.12) and 0.97 (95% CI, 0.94 to 1.00) for multi- and single-center surgeons (p < 0.001). For multicenter surgeons, the observed-to-expected mortality ratios were 1.17 (95% CI, 1.09 to 1.27) versus 1.01 (95% CI, 0.96 to 1.07), p < 0.001, for their satellite versus home facilities, respectively.

Single-center surgeons performing CABG had lower risk-adjusted outcome rates compared with multicenter surgeons, who performed better at their home versus satellite hospitals. To improve future quality of care, surgeons, health care networks, and health policy makers should now more closely scrutinize their single versus multicenter performance.