Background The timing of surgery in asymptomatic severe mitral regurgitation (MR) remains controversial. This study sought to compare long-term outcomes of early surgery with a conventional treatment strategy in asymptomatic patients with severe MR.

Methods From 1996 to 2016, a total of 1,063 consecutive asymptomatic patients (673 men, age; 51±14 years) with severe degenerative MR and preserved left ventricular function were enrolled, and followed prospectively for a median of 12 years (interquartile range: 8 to 17 years). Early surgery was performed on 545 patients, while the conventional treatment strategy was chosen for 518. We compared overall and cardiac mortality between these two treatment strategies using propensity score adjustment.

Results In the early surgery group, there was no operative mortality and mitral valve repair was successfully performed in 97% of patients. During follow-up, 8 patients (1.5%) in the early surgery group and 54 (10.4%) in the conventional management group died from cardiovascular causes (hazard ratio [HR], 0.17; 95% CI, 0.15 to 0.64; P = 0.001). A total of 74 deaths (13.6%) from any cause occurred in the early surgery group, whereas 116 (22.4%) occurred in the conventional management group (HR, 0.72; 95% CI, 0.52 to 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 (HR, 0.18; 95% CI, 0.08 to 0.43; P < 0.001) and significantly lower cardiac mortality rates (5.6% vs. 17.4 % at 20 years; P < 0.001). Compared with the conventional treatment group, the early surgery group also had a significantly lower risk of overall mortality (HR, 0.66; 95% CI, 0.47 to 0.93; P = 0.018) and significantly lower overall mortality rates (28.2% vs. 33.9% at 20 years; P = 0.022).

Conclusions Compared with conventional management, early surgery is associated with reduced long-term cardiac and overall mortality among asymptomatic patients with severe MR and preserved left ventricular function (ClinicalTrials.gov number, NCT01703806).

The authors have declared no competing interest.

ClinicalTrials.gov number, NCT01703806

No external funding was received.

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Asan Medical Center IRB

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