Association between individual surgeon volume and outcome in mitral valve surgery: a systematic review

BACKGROUND: Surgeon volume has been identified as a possible factor that influences outcomes in mitral valve (MV) surgery. The aim of this study was to systematically review all published studies on the association between individual surgeon volume and outcome in MV surgery. METHODS: PubMed was searched last on 19 November 2020. The reporting of this systematic review was done in accordance with PRISMA guidelines. Manuscripts were eligible when these studied individual surgeon volumes and its association with repair rate, mortality or reoperation. The methodological quality of the studies was assessed with the Newcastle-Ottawa Scale (NOS). Absolute numbers and percentages of the outcome measures, odds ratios (ORs), P values and threshold values regarding surgeon volume were collected. RESULTS: A total of 7 retrospective cohort studies were included in the qualitative analysis with total of 158488 patients. Definitions of surgeon volumes were found to be heterogenic and therefore pooling of data was not possible. Surgeon volume was significantly associated with repair rate (OR =1.25–5.5) and mortality (OR =0.46–0.84 and OR =1.50–2.27 depending on the reference group). Regarding reoperation, results were not consistent and did not always show a significant lower reoperation rate when surgeon volume increased. A mean threshold of minimally 30 MV surgeries per year was found. DISCUSSION: Higher surgeon volume is significantly associated with improved outcomes of repair rate and mortality. MV should preferentially be performed by high-volume surgeons and centralization of MV surgery might be necessary.