Abstract 4368307: Impaired Myocardial Perfusion in Patients with Primary Mitral Regurgitation Due to Mitral Valve Prolapse

Abstract

Background: Mitral valve prolapse (MVP) is frequently associated with mitral regurgitation (MR), which increases left ventricular (LV) preload and can lead to LV hypertrophy. In other disease states, elevated LV preload, has been associated with reduced coronary flow reserve due to increased resting coronary flow, resulting in impaired myocardial perfusion. However, myocardial perfusion at rest and under stress has not previously been characterized in patients with MVP and significant MR. Aim: To evaluate myocardial perfusion in patients with moderate or severe MR due to MVP compared with controls without MVP and MR, using cardiac magnetic resonance (CMR) imaging with adenosine stress perfusion mapping. Methods: Patients with MVP and moderate or severe MR referred for mitral valve surgery were prospectively enrolled in the MitraVT study (NCT06255457) and were compared to age- and sex-matched controls without MVP and primary MR. All participants underwent CMR at 1.5T (MAGNETOM Sola, Siemens Healthineers), including cine imaging and adenosine stress perfusion mapping. Exclusion criteria included coronary artery disease, rheumatic mitral disease, mitral stenosis, endocarditis, or primary cardiomyopathy. Myocardial perfusion was quantified for each of the 16 segments defined by the American Heart Association, both at rest and under stress. Global perfusion values were calculated as the mean across all segments. Clinical data were obtained from medical records. Results: In total, 20 patients and 20 controls were included (age 53.9±15.2 vs. 52.2±13.2 years, 55% vs. 55% female) with no differences in the prevalence of diabetes, hypertension, hyperlipidemia, or smoking status. Compared to controls, patients with primary MR had higher indexed end-diastolic LV volume, stroke volume index, and ejection fraction. Global myocardial perfusion was significantly reduced among patients with MVP and MR, both at rest (0.82±0.20 vs.1.04±0.32 ml/min/g, p=0.01) and at stress (2.46±0.45 vs. 3.44±0.71 ml/min/g, p<0.001) (Figure 1). These differences remained significant when comparing the mean perfusion values across basal, midventricular, and apical levels. Conclusion: Patients with MVP and moderate or severe MR exhibited significantly reduced myocardial perfusion both at rest and at stress, indicative of coronary microvascular dysfunction. Future studies are needed to assess whether mitral valve surgery restores myocardial perfusion and improves symptom burden in this population.