Abstract 4339808: Impact of Left Atrial Strain on Outcomes of Severe Mitral Regurgitation due to Severe Mitral Annular Calcification

Background: Mitral annular calcification (MAC) is a progressive degenerative condition characterized by calcium deposition along the mitral valve annulus. It is increasingly prevalent in older adults and is associated with elevated morbidity and mortality. However, data on mitral regurgitation (MR) secondary to MAC remain limited. This study aimed to evaluate the prognostic significance of left atrial strain (LAS) and left ventricular global longitudinal strain (LV-GLS) in patients with isolated severe MR due to severe MAC. Methods: We conducted a retrospective cohort study at a single tertiary care center. Patients with severe MAC were identified from the institutional echocardiographic database, and those with isolated severe MR were selected for inclusion. The primary endpoint was all-cause mortality. Conventional echocardiographic parameters, LAS, and LV-GLS were recorded. The cohort was stratified by the median reservoir LAS (LASr). Results: Between January 2010 and August 2023, a total of 128 patients with isolated severe MR due to MAC were enrolled. Median follow-up period was 134 days (IQR: 33–1,812). The median age was 81 years (IQR: 71–88), and 65% were female. Mean left ventricular ejection fraction (LVEF) was 61% ± 13%; median LV-GLS was -15.4% (IQR: -19.4 to -14.1%) and median LASr was 14.1% (IQR: 10.75–20.0). A total of 45 patients (35.2%) underwent mitral valve (MV) intervention, while 83 patients (64.8%) received conservative management. Among those who underwent intervention, 42 patients (93.3%) underwent surgery and 3 (6.7%) underwent percutaneous mitral clip implantation. Of the surgical cases, 37 underwent valve replacement, including 34 with bioprosthetic valves, and 5 underwent repair. During follow-up, 63 patients (49.2%) died. Outcomes were worse in patients with LASr below the median (p = 0.011), while LV-GLS was not significantly associated with mortality (p = 0.247). Stratification by LASr median and treatment showed best outcomes in those with higher LASr who underwent intervention and worst in those with lower LASr managed conservatively (p < 0.001). In multivariate Cox analysis, each unit decrease in LASr was associated with increased mortality risk (HR: 1.054; 95% CI: 1.002–1.109), while MV intervention reduced mortality (HR: 0.173; 95% CI: 0.075–0.397). Conclusion: LASr is associated with all-cause mortality in patients with isolated severe MR due to MAC, and may be a valuable tool for risk stratification.