Clinical outcomes after edge-to-edge percutaneous repair in atrial versus ventricular functional mitral regurgitation

Abstract Background In recent years, a new etiological entity of functional mitral regurgitation, known as atrial functional mitral regurgitation (A-FMR), has been described, which differs from the classic ventricular functional mitral regurgitation (V-FMR) by preserving normal left ventricular size and function. In both cases, when mitral regurgitation (MR) is severe, edge-to-edge percutaneous repair (EEPR) has emerged as a therapeutic alternative. Few studies, most of them multicenter, have directly compared outcomes between both etiologies suggesting a more favorable prognosis in A-FMR. Purpose Our aim was to perform a real-life comparison to evaluate the impact of EEPR in both forms of functional MR through a retrospective analysis of a prospective single-center registry. Methods From a total of 220 patients who underwent EEPR for severe MR in our center between November 2011 and January 2025, we selected those with functional MR, excluding degenerative and mixed etiologies. A-FMR was defined by preserved left ventricular ejection fraction (LVEF ≥ 50%) and absence of ventricular dilatation (left ventricular end-diastolic diameter ≤ 55 mm/m²). Patients not meeting these criteria were classified as V-FMR. Results A total of 137 patients were included, with a male predominance (70%) and a mean age of 66±14 years. The median follow-up was 26 months. Among them, 116 patients (85%) were classified as V-FMR and 21 (15%) as A-FMR. Baseline clinical characteristics are summarized in Table 1. Patients with A-FMR were older, more frequently female, frailer and had less coronary artery disease. There were no significant differences in acute procedural success or MR reduction between groups. At 24 months post-EEPR, event-free survival was similar between A-FMR and V-FMR patients (51% vs 46%, p = 0.8) (Figure 1). We also found no differences in overall survival (71% vs 74%, p = 0.4) (Figure 1). Conclusions EEPR provides a similar reduction in MR severity in both atrial and ventricular functional mitral regurgitation. After 24 months of follow-up, no significant differences were observed between etiologies in terms of event-free survival or overall survival, suggesting that EEPR is an effective therapeutic option regardless of the underlying mechanism of functional mitral regurgitation.Table 1 Figure 1