Relative Survival Following TEER for Significant Mitral Regurgitation: A Contemporary Cohort Analysis

<b>Background/Objectives:</b> Mitral regurgitation (MR) is the most common valvular defect worldwide, with an increasing incidence attributed to the aging population. Transcatheter edge-to-edge repair (TEER) is a viable treatment, but its long-term survival impact, particularly across sexes, remains underexplored. We aimed to assess relative survival (RS) and excess mortality (EM) in patients undergoing TEER for significant MR, with a focus on sex-based differences. <b>Methods:</b> We analyzed 253 patients treated with TEER between October 2015 and August 2024, stratified by sex. Observed survival (OS) was calculated using the actuarial life table method; expected survival (ES) was estimated via the Ederer II method using matched population data. Primary endpoints were RS and EM; secondary endpoints included mortality differences by MR subtype. <b>Results</b>: OS at 1, 2, and 3 years was 88.9%, 87.4%, and 78.9%, respectively. EM peaked in the first year (7.8%) and declined thereafter. RS was lower than in the general population, primarily due to persistently reduced RS and elevated EM in men. Women achieved RS comparable to matched peers from year one. Sex was not an independent predictor of mortality (HR 0.88, 95% CI 0.38-2.03, <i>p</i> = 0.771). <b>Conclusions</b>: In patients with significant MR undergoing TEER, EM was concentrated in the first year. Women reached RS comparable to the general population, while men showed persistent excess mortality. Sex was not independently associated with survival after adjustment.