Early Surgery Linked to Improved Long-Term Survival in Asymptomatic Severe Primary Mitral Regurgitation: JAMA

A new study published in the Journal of American Medical Association showed that prompt surgical treatment improved the long-term survival of individuals with asymptomatic severe primary mitral regurgitation (MR) even prior to the onset of left ventricular decompensation.

The best time for mitral valve (MV) surgery in individuals with asymptomatic severe primary MR is not clear due to the absence of randomized clinical trials. Hence, this research aimed to assess the link between early MV surgery and the extended survival of patients with asymptomatic severe primary MR by employing a target trial emulation framework.

In this cohort study, data from a clinical valve registry at three major hospitals in South Korea spanning from 2000 to 2022 was utilized. The study focused on patients diagnosed with severe primary MR who were asymptomatic. A method known as a clone-censor-weight approach was employed to mimic a target trial. A six-month grace period following diagnosis was considered to establish treatment plans. The main outcome under scrutiny was the overall mortality rate, while the secondary outcome comprised a combination of all-cause mortality and hospitalization due to heart failure. 

In a group of 802 individuals (with an average [standard deviation] age of 55 [16] years, including 476 males [59%]), 344 opted for early surgical intervention while 458 chose watchful waiting. Over a period of 7.4 (4.1-11.6) years on average, there were 27 deaths in the early surgery category and 103 in the watchful waiting group.

After 5 years, opting for early surgery led to an increase in time to a critical event by 66 days (95% confidence interval, 19-129 days). This advantage in survival was noticeable for up to 15 years. Early surgery was linked with a reduced risk of death from any cause when compared to watchful waiting (hazard ratio, 0.69; 95% confidence interval, 0.41-0.94; P = .02).

Similar trends were seen in patients without left ventricular decompensation (hazard ratio, 0.61; 95% confidence interval, 0.31-0.96; P = .04) and those with degenerative mitral regurgitation (hazard ratio, 0.66; 95% confidence interval, 0.36-0.98; P = .04). Overall, individuals with severe primary MR but no symptoms, scientists showed the considerable advantages in survival linked to early MV surgery in a medical environment. This applies to patients showing no signs of LV dysfunction and those with degenerative MR.

Source:

Ahn, J., Kwak, S., Lim, J., Kim, K., Kim, J., Sun, B. J., Kim, D.-H., Kim, K. H., Shim, C. Y., Park, S.-J., Won, S., & Lee, S.-P. (2026). Early mitral valve surgery and survival in asymptomatic severe primary mitral regurgitation. JAMA Network Open, 9(10), e2637061. https://doi.org/10.1001/jamanetworkopen.2026.37061