Long-term causes of death in patients who underwent mitral transcatheter edge-to-edge repair

BACKGROUND Transcatheter mitral edge-to-edge repair (M-TEER) has transformed the management of patients with severe mitral regurgitation (MR) at high or prohibitive surgical risk. However, data on long-term survival and causes of death after M-TEER remain limited. METHODS AND RESULTS This single-center registry included consecutive patients undergoing M-TEER with the MitraClip device for severe MR between February 2016 and June 2020. The primary objective was long-term mortality trends and causes of death. Over a median follow-up of 3.3 years (IQR 1.3-5.1; maximum 8.5 years), 130 of 218 patients (59.6%) died, with 55.4% due to cardiovascular (CV) causes, mainly heart failure (HF, 34.6%). Non-CV deaths were attributed to sepsis (15.4%), malignancy (10.8%), trauma (3.8%), and multi-organ failure (1.5%). CV mortality accounted for 55% of deaths within 1 year and 68.4% beyond 5 years, with no significant change in the CV/non-CV mortality ratio over time. Among 88 survivors, non-fatal CV events were infrequent: 12.5% were rehospitalized for HF and 2.3% underwent repeat M-TEER. Non-CV hospitalizations occurred in 9.1%, mainly due to fractures or pneumonia. Independent predictors of all-cause mortality included ischemic secondary MR etiology, prior HF, TAPSE/sPAP ≤0.36, and ≥moderate tricuspid regurgitation, while a low MitraScore predicted better survival. A low MitraScore risk was associated with a significantly lower all-cause and CV mortality compared to a high Mitrascore risk (48.6% vs 83.9%, p < 0.001; 21.0% vs 64.4%, p ≤ 0.001). CONCLUSION Long-term mortality after M-TEER remains influenced by extra-mitral cardiac involvement and non-cardiac comorbidities. The MitraScore preserves its prognostic accuracy during extended follow-up.