Timing of Valve Repair for Asymptomatic Mitral Regurgitation and Preserved Left Ventricular Function.

Background: According to current guidelines, mitral valve repair is reasonable in asymptomatic patients with severe degenerative mitral regurgitation and preserved left ventricular (LV) function. However, the surgical timing is challenging. This study aims to identify risk factors and delineate a quantitative threshold for predicting postoperative outcomes.

Methods: In all, 623 asymptomatic degenerative mitral regurgitation patients with left ventricular ejection fraction (LVEF) 60% or greater and LV end-systolic diameter less than 40 mm who underwent mitral valve repair were retrospectively reviewed. Logistic regression analysis and receiver-operating characteristics curves were used to analyze predictors for early postoperative LV dysfunction (LVEF less than 50%), and mid to long-term outcomes were analyzed by Kaplan-Meier analysis.

Results: The postoperative inhospital mortality was 0.96%. Survival at 1, 3, 5, and 10 years was 98.8%, 97.7%, 94.5%, and 90.4%, respectively; and freedom from moderate or severe mitral regurgitation at 1, 3, 5, and 10 years was 98.6%, 95%, 92.4%, and 83.6%, respectively. Logistic regression analysis indicated that early postoperative LV dysfunction was associated with preoperative LVEF (hazard ratio 0.933; 95% confidence interval, 0.891 to 0.977; P = .003) and left atrial volume index (hazard ratio 1.212; 95% confidence interval, 1.106 to 1.329; P < .001). Receiver-operating characteristics curve analysis identified preoperative LVEF 65% (area under the curve 0.765; P < .001) and left atrial volume index 53 mL/m2 (area under the curve 0.733; P < .001) as the best cutoff values for predicting early postoperative LV dysfunction. Furthermore, midterm to long-term survival was significantly lower among patients with early postoperative LV dysfunction than among patients with normal LV function (hazard ratio 3.19; 95% confidence interval, 1.41 to 7.23; P = .005).

Conclusions: Preoperative LVEF and left atrial volume index were the predictors for early postoperative LV dysfunction, which further lead to poor long-term survival after mitral valve repair in asymptomatic degenerative mitral regurgitation patients with preserved LV function. Surgery intervention should be encouraged before onset of LVEF less than 65% or left atrial volume index 53 mL/m2 or more.