Risk of Surgical Mitral Valve Repair for Primary Mitral Regurgitation.

ABSTRACT

BACKGROUND: Risk estimation for surgical intervention is an essential component of heart team shared decision-making. However, current mitral valve (MV) surgery risk models used in practice lack etiologic or procedural specificity. The purpose of this study was to establish a comprehensive method for assessment of operative risk of MV repair of primary mitral regurgitation (MR). METHODS: A novel etiology and procedure-specific algorithm identified 53,462 consecutive (July 2014 to June 2020) intention-to-treat MV repair patients with primary MR from The Society of Thoracic Surgeons Adult Cardiac Surgery Database. Risk models were fit for 30-day operative mortality, mortality and/or major morbidity, and conversion-to-replacement (CONV). As-treated mortality and morbidity models were derived separately. RESULTS: Event rates for mortality (n = 619; 1.16%), mortality plus morbidity (n = 4746; 8.88%), and CONV (n = 3399; 6.36%) were low. Mortality was higher in CONV patients vs repair (3.18% vs 1.02%). All event rates were lower with increasing program volumes. The mortality risk model had excellent discrimination (AUC 0.807) and calibration and confirmed very low mortality risk for isolated MV repair for primary MR, with mean mortality risk of 1.16% and median of 0.55% (interquartile range 0.30%-1.17%) with 90th and 95th percentiles 2.48% and 3.99%, respectively. The mortality risk was <0.5% in patients <65 years of age, with 97% of the total population across age groups having a risk of <3%. Only 1 in 4 patients age 75 or older had >3% estimated risk of mortality. CONCLUSIONS: This etiologic and procedure-specific risk model establishes that the contemporary mortality risk of MV repair for primary MR is <1% for the vast majority of patients.