Abstract 12425: The Interplay Between Left Atrial and Mitral Valvular Remodeling in Subtypes of Mitral Regurgitation

Abstract

Background: The interaction between left atrial (LA) mechanics and mitral valve remodeling patterns in patients with mitral regurgitation (MR) is poorly described. Objectives: To assess three-dimensional (3D) LA volumes and strain in relation to 3D mitral valve morphology in patients with degenerative vs. functional MR. Methods: Patients included in the 3D-PRIME (3D Echocardiography and Cardiovascular Prognosis in Mitral Regurgitation) study at our heart valve clinic between 2020-2022 and with moderate or severe MR by combined transthoracic/transesophageal assessment were examined. LA remodeling was assessed by 3D maximum and minimum LA volume, reservoir strain (LASr) and contraction strain (LASct). Mitral valve annulus area, anterior and posterior leaflet length and area, tenting volumes and non-planar angle were measured using dedicated 3D mitral valve software. Results: 100 patients with moderate or severe MR were included. Patients with atrial functional MR (n=26) were older, more often women and had higher heart rate compared to degenerative MR (n=54) and ventricular functional MR (n=20) (p <0.05). They also had larger LA volumes and severely impaired LASr and LASct despite smaller MR regurgitation volumes compared to MR by other mechanisms (Figure). Mitral annulus area was comparable between groups, but anterior mitral leaflet was higher, with larger area and the non-planar angle wider in functional MRs (p <0.05). In multivariable analysis, low LASr (below median) was associated with larger LA volume, and higher anterior mitral leaflet height independent of age, sex, heart rate, left ventricular global longitudinal strain, and right ventricular stroke volume (Nagelkerke R 2 0.67, p <0.01). In a similar model, low LASct was only associated with larger LA volumes. Conclusions: Patients with atrial functional MR have large LAs with severely impaired LA function and a specific mitral valve remodeling pattern at lower MR regurgitation volumes.