Mitral valve surgery (MVS) refers to the repair or replacement of the mitral valve in the heart. Doctors recommend early surgery for severe primary degenerative mitral regurgitation if the optimal outcomes could be achieved. This study aims to investigate the 30-day and 1-year outcomes of mitral valve surgery.

In this multicenter, cross-sectional observational cohort study, a total of 55,311 patients, along with 1,094 hospitals and 2,410 surgeons, were included. The included patients were undergoing isolated mitral valve repair or replacement for primary mitral regurgitation. The primary outcome of the study was 30-day in-hospital operative mortality, along with 30-day composite mortality and 1-year mortality.

The findings suggested that increasing hospital and surgeon volumes were associated with a reduced risk of risk-adjusted 30-day mortality, along with lower 30-day composite mortality & morbidity and a higher rate of a successful repair. The highest vs. lowest hospital volume quartile reported a higher 1-year risk-adjusted mortality (HR 1.61), but not a higher risk for mitral reoperation or hospitalization for heart failure. The surgeon-level volume associations were also similar to mortality.

The research concluded that there were significant hospital- and surgeon-level inverse volume-outcome associations for 30-day and 1-year mortality in patients undergoing mitral valve repair or replacement.