Mitral valve repair in the United States: Single-center versus multicenter surgeons' risk-adjusted outcomes.

Objectives: Health care consolidation may force cardiac surgeons to operate at multiple centers. Few data exist as to this phenomenon's effect upon patients' quality of care as measured by risk-adjusted outcome (RAO) rates. We sought to compare mitral valve repair (MVr) RAO rates between surgeons operating at multiple centers (MC) versus single-centers (SC); and for MC surgeons, to compare MVr RAO rates between their primary and secondary centers.

Methods: The 2011-2019 Society of Thoracic Surgeons Adult Cardiac Surgery Database's MVr records were analyzed. MC surgeons performed MVr procedures at ≥2 centers within a year; each MC surgeon's greatest MVr volume ("primary") center was identified. Applying the Society of Thoracic Surgeons-approved 2018 isolated-MVr risk models, study end points included risk-adjusted 30-day major morbidity or mortality (MMM; determined by operative death, dialysis, stroke, prolonged ventilation, mediastinitis, or repeat procedure) and risk-adjusted prolonged length of stay (pLOS). The impacts of surgeon's and hospital's MVr and total cardiac surgery volumes were evaluated.

Results: Compared with MC surgeons, SC surgeons had lower risk-adjusted MMM (odds ratio [OR], 1.170; P < .001). After adjusting for surgeon and center volumes, this finding persisted (OR, 1.141; P = .0155). MC surgeons experienced lower risk-adjusted MMM at their primary versus secondary centers (OR, 1.269; P < .001); this finding was partially attributable to center-based volume variations (OR, 1.130; P = .098). No SC versus MC surgeon risk-adjusted pLOS differences were found; however, regional risk-adjusted pLOS differences persisted.

Conclusions: Compared with SC surgeons, reallocating surgeons' caseload across multiple centers has a statistically significant, negative impact on their MVr RAO rates.