Impact of maintaining mild mitral regurgitation beyond 1 year after mitral transcatheter edge-to-edge repair

INTRODUCTION: Residual mitral regurgitation (MR) after mitral transcatheter edge-to-edge repair (M-TEER) is associated with adverse prognosis. However, the long-term clinical impact of MR persistence or progression has not been well stratified. We aimed to evaluate the proportion, clinical benefits, and prognostic value of maintaining mild MR 1 year after M-TEER. METHODS AND RESULTS: This multi-centre registry-based analysis included 1865 patients who achieved mild MR at discharge following M-TEER. At 1 year, patients were classified as having stable MR (≤ mild) or worsening MR (≥ moderate). The frequency of left atrial (LA) and left ventricular (LV) reverse remodelling and tricuspid regurgitation (TR) improvement were assessed from baseline to 1 year. Clinical endpoints-including all-cause mortality and heart failure hospitalization-were evaluated beyond 1 year after M-TEER up to 2 years. Worsening MR occurred in 28.4% of patients. Compared with the worsening MR group, the stable MR group demonstrated significantly more frequent LA and LV reverse remodelling (38.4% vs 28.1%, and 44.7% vs 31.1%, respectively; both P < .001). Improvement in TR (≥ Grade 1) was also more prevalent in the stable MR group (32.4% vs 20.6%, P < .001). Worsening MR was independently associated with increased risk of adverse clinical outcomes (hazard ratio: 2.02; 95% confidence interval: 1.26-3.23; P = .003). CONCLUSION: Maintaining MR within mild at 1-year post-M-TEER is associated with favourable cardiac reverse remodelling and improved clinical prognosis. These findings underscore the importance of long-term MR surveillance and its implications for outcome optimization following M-TEER.