Long-Term Outcomes of Early Surgery Versus Conventional Treatment for Asymptomatic Severe Mitral Regurgitation: A Propensity Analysis

BACKGROUND: The timing of surgery in asymptomatic severe mitral regurgitation remains controversial. This observational study sought to compare long-term outcomes of early surgery with a conventional treatment strategy in asymptomatic patients with severe mitral regurgitation. METHODS: From 1996 to 2016, a total of 1063 consecutive asymptomatic patients (673 men; mean±SD age, 51±14 years) with severe degenerative mitral regurgitation and preserved left ventricular function were enrolled, and followed prospectively for a median of 12 years (interquartile range, 8–17 years). Early surgery was performed on 545 patients and the conventional treatment strategy was chosen for 518 patients. We compared overall and cardiac mortality rates between these 2 treatment strategies using propensity score adjustment. RESULTS: In the early surgery group, no operative deaths occurred, and mitral valve repair was successfully performed in 97% of patients. During follow-up, 8 (1.5%) patients in the early surgery group and 54 (10.4%) in the conventional management group died from cardiovascular causes (hazard ratio, 0.17 [95% CI, 0.07–0.40]; P <0.001). A total of 74 (13.6%) deaths from any cause occurred in the early surgery group, whereas 116 (22.4%) occurred in the conventional management group (hazard ratio, 0.72 [95% CI, 0.52–0.99]; P =0.046). For the 358 propensity score matched pairs, the early surgery group had a significantly lower risk of cardiac mortality than the conventional treatment group (hazard ratio, 0.18 [95% CI, 0.08–0.43]; P <0.001) and significantly lower cardiac mortality rates (5.6% versus 17.4% at 20 years; P =0.002). Compared with the conventional treatment group, the early surgery group also had a significantly lower risk of overall mortality (hazard ratio, 0.66 [95% CI, 0.47–0.93]; P =0.018) and significantly lower overall mortality rates (28.2% versus 33.9% at 20 years; P =0.015). CONCLUSIONS: Compared with conventional management, early surgery is associated with better long-term outcomes among asymptomatic patients with severe mitral regurgitation and preserved left ventricular function. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01703806.