Abstract 4138007: Mechanisms of Mitral Regurgitation in Fabry Disease

Introduction: Fabry disease, caused by mutations in the gene encoding alpha-galactosidase A, results in the accumulation of globotriaosylceramide (Gb3), leading to systemic complications including cardiac involvement such as mitral regurgitation (MR). The aim of this study is to investigate the association between MR severity and mitral leaflet morphology in Fabry disease patients. A cohort of 38 symptomatic Fabry disease patients with moderate or significant MR was followed up. Mitral leaflet morphology was categorized as normal, fibrodegenerative changes, or leaflet thickening. MR severity varied, with the primary cause being leaflet restriction. Additionally, left ventricular outflow tract obstruction (LVOTO) and annular dilatation were observed. The study suggests that MR in Fabry disease is primarily due to leaflet restriction, either through degenerative changes or leaflet thickening. This study investigates the association between MR severity and mitral leaflet morphology in Fabry disease patients. Methods: A cohort of 38 symptomatic Fabry disease patients with moderate or significant MR was followed up. Echocardiographic assessments were conducted to determine MR severity and categorize mitral leaflet morphology. Statistical analyses were performed to evaluate associations between MR severity and leaflet morphology. Echocardiographic assessments of the mitral valve were conducted using a Vivid E95 Cardiac Ultrasound and meticulously analyzed using the EchoPAC TM and TOMTEC Imaging Systems. A crucial aspect of the examination involved measuring all components of the mitral valve and determining the requisite angles to evaluate each mechanism thoroughly. Results: Most patients exhibited leaflet restriction as the primary cause of MR, with varying degrees of severity. Mitral leaflet morphology was categorized as normal in 15,8%, fibrodegenerative changes were in 31,5% and leaflet thickening in 52,7%. In addition, outflow tract obstruction (LVOTO) was observed in 15,7% but without systolic anterior motion (SAM) and annular dilatation (dilatation of anteroposterior annulus more than 35 mm in systole) was present in 66%. Conclusion: The study suggests that MR in Fabry disease is primarily attributed to leaflet restriction, either due to degenerative changes or leaflet thickening. An additional, albeit not unexpected, finding not always considered is the presence of anteroposterior annular dilatation in some cases.