Asymptomatic Severe Mitral Regurgitation: Early Surgery vs Watchful Waiting

Mitral valve (MV) surgery within 6 months of diagnosis was associated with improved long-term survival compared with watchful waiting in patients with asymptomatic severe primary mitral regurgitation (MR), according to a multicenter cohort study published in JAMA Network Open.

The investigators noted that the optimal timing of surgery in asymptomatic patients remains uncertain because randomized clinical trials are lacking. They analyzed a valve registry from 3 tertiary hospitals in Seoul, South Korea, covering 2000 to 2022, using a target trial emulation framework with a clone-censor-weight approach. The primary outcome was all-cause mortality, assessed primarily by restricted mean survival time (RMST).

Among 802 patients (mean age, 55 years; 59% men), 344 underwent early surgery and 458 underwent watchful waiting. Over a median follow-up of 7.4 years, 27 deaths occurred in the early surgery group and 103 in the watchful waiting group. At 5 years, early surgery was associated with an RMST gain of 66 days (95% CI, 19-129 days), with weighted 5-year survival of 91.9% vs 85.4%. Early surgery was also associated with a lower risk of all-cause mortality (hazard ratio [HR], 0.69; 95% CI, 0.41-0.94).

Similar associations were observed among patients without left ventricular decompensation (HR, 0.61; 95% CI, 0.31-0.96) and those with degenerative MR (HR, 0.66; 95% CI, 0.36-0.98). Results were consistent with 3- and 12-month grace periods. In the watchful waiting group, 18.8% of patients later underwent surgery.

The authors described the 5-year absolute benefit as modest, noting that it may partly reflect low mortality with watchful waiting. They also reported that unmeasured factors, such as surgeon experience and patient preferences, could not be fully accounted for and that findings from tertiary referral centers may not be generalizable to other settings.

Source: Ahn J, Kwak S, Lim J, et al. Early mitral valve surgery and survival in asymptomatic severe primary mitral regurgitation. JAMA Netw Open. 2026;9(10):e2637061. doi:10.1001/jamanetworkopen.2026.37061