Asymptomatic degenerative mitral regurgitation repair: Validating guidelines for early intervention

Introduction: Mitral repair for asymptomatic (New York Heart Association [NYHA] class I) degenerative mitral regurgitation (MR) is supported by the guidelines, but is not performed often. We sought to determine outcomes for asymptomatic patients when compared with those with symptoms. Methods: Between 2004 and 2018, 1027 patients underwent mitral replacement (22) or repair with or without other cardiac surgery (1005), the latter being grouped by NYHA class: I (n = 470; 47%), II (n = 408; 40%), or III/IV (n = 127; 13%). Statistical analyses included propensity score matching and weighting, and multistate models. Results: The proportion of patients designated as NYHA class I undergoing surgery increased steadily during this period (P <.001). Overall, 30-day mortality was 0.4%, and zero for patients designated NYHA class I. Unadjusted 10-year survival was significantly greater in patients designated NYHA class I compared with II and III/IV (P <.001). Freedom from reoperation at 10 years was 99.8% overall, and 100% for patients designated NYHA class I. In patients designated as NYHA class I, predischarge and 10-year moderate MR were 0.7% and 20.1%, whereas more than moderate was zero and 0.6%. Preoperative ejection fraction less than 60% was associated with late mortality (P =.025). After covariate-adjustments, freedom from MR and tricuspid regurgitation were not statistically significantly different by NYHA class. However, overall survival was significantly worse in patients with NYHA class III/IV, compared with class II. Conclusions: Mitral repair in asymptomatic patients is safe and durable. Careful monitoring until class II symptoms is appropriate. However, repair before ejection fraction decreases below 60% is important for late overall survival.