Afterload mismatch after transcatheter edge‐to‐edge repair in functional mitral regurgitation: A propensity‐score matched analysis

BACKGROUND: Transcatheter edge-to-edge repair (TEER) for severe functional mitral regurgitation (FMR) in patients with reduced left ventricular ejection fraction (LVEF) may lead to an acute increase in left ventricular afterload, termed afterload mismatch (AM). This study aimed to redefine AM clinically, analyse its determinants, and assess its prognostic impact post-TEER in FMR patients. METHODS: A multicenter case-control study was conducted, involving FMR patients with LVEF ≤35% undergoing TEER. AM post-TEER was defined as the acute (within 24 h) need for escalation of inotropic or mechanical circulatory support. Sixty-eight AM cases were compared with 68 propensity-matched patients. Primary endpoints included in-hospital mortality post-TEER and 2-year all-cause mortality. RESULTS: Median age was 68 years, 76% male. Procedural success was achieved in 92% of patients. Proportionate MR was associated with a higher risk of AM (adj-HR 1.6, 95% CI 1.01-2.6, p = .04). Conversely, pretreatment with levosimendan (adj-HR .29, 95% CI .12-.70, p < .01) and higher furosemide dose (adj-HR per furosemide 10 mg increase .86, 95% CI .76-.98, p = .03) were protective. In-hospital mortality was higher in the AM cohort (10% vs. 2%, p = .03), while 2-year mortality rates were similar (34% vs. 20%, p = .09). Multivariable analysis revealed higher AM grades and post-procedural MR as predictors of in-hospital mortality and lack of procedural success for 2-year mortality. CONCLUSIONS: Among patients with LVEF ≤35% and severe FMR undergoing TEER, AM was associated with in-hospital mortality but did not impact long-term outcomes. Proportionate MR increased the risk of AM, while pretreatment with levosimendan and higher furosemide doses was protective.