Supplementary Material for: The influence of left ventricular ejection fraction on long-term survival of patients after transcatheter edge-to-edge mitral valve repair

Background: Transcatheter edge-to-edge repair (M-TEER) has emerged as an effective treatment for high-risk patients suffering from mitral regurgitation (MR), alleviating symptoms and improving outcomes. However, the prognostic relevance of left ventricular ejection fraction (LVEF) in this population remains unclear.

Methods: We analyzed data from 821 patients undergoing M-TEER at four German tertiary care centers between 2011 and 2022. Patients were stratified into heart failure subgroups based on LVEF: heart failure with preserved ejection fraction (HFpEF, LVEF ≥50%), mildly reduced ejection fraction (HFmrEF, LVEF 41–49%), and reduced ejection fraction (HFrEF, LVEF ≤40%). Propensity score matching was used to balance baseline characteristics. The primary endpoint was all-cause mortality, with secondary endpoints including cardiovascular mortality and major adverse cardiac and cerebrovascular events (MACCE).

Results: HFrEF patients exhibited greater comorbid burden, including higher rates of coronary artery disease and functional MR. Despite these differences, no significant association was observed between LVEF and long-term mortality, even after propensity score matching. Long-term survival rates at three years were similar across subgroups: 50.8% for HFrEF, 60.6% for HFmrEF, and 58.9% for HFpEF (p=0.2). Patients with HFrEF experienced higher in-hospital mortality (5.2%) than HFmrEF (0%) and HFpEF (2.5%), primarily due to non-cardiac causes. The overall rate of major adverse cardiac and cerebrovascular events (MACCE) was low at 3.8% (31/821) without significant difference between the respective subgroups. Multivariable analysis identified high-grade tricuspid regurgitation, chronic obstructive pulmonary disease, and impaired renal function as stronger predictors of mortality than LVEF.

Conclusions: LVEF demonstrated limited prognostic value for long-term outcomes following M-TEER, challenging its role as a standalone marker in this population. Procedural safety and efficacy were consistent across subgroups, underscoring the viability of M-TEER in surgically inoperable patients. Given the significant higher in-hospital mortality rate due to non-cardiac causes in the HFrEF subgroup, tailored therapeutic strategies addressing the underlying diseases should be pursued to optimize outcomes. Future studies should explore possible improvements in risk assessment and patient selection, for example by integrating emerging imaging modalities and accounting for comorbidities, to improve treatment outcomes.