Abstract 12200: Comparison of Exercise-Induced Hemodynamic Changes Between Anterior and Posterior Mitral Prolapse in Patients With Asymptomatic Degenerative Mitral Regurgitation

Background: Exercise-induced hemodynamic changes depending on the location of prolapsed leaflet have not been elucidated. The study tried to compare exercise-induced hemodynamic changes between AML and PML prolapse in asymptomatic degenerative MR. Methods: We enrolled 29 patients with asymptomatic moderate to severe degenerative MR (i.e., mitral valve prolapse or flail) and patients were classified by the location of prolapsed leaflet including 15 with anterior mitral leaflet [AML] and 14 with posterior mitral leaflet [PML]. Resting and semi-supine bicycle exercise Doppler-echocardiography were performed and MR was quantified at rest and exercise with effective regurgitant orifice area (EROA) and regurgitant volume calculated with the proximal isovelocity surface area (PISA) and the quantitative Doppler methods. Exercise-induced PHTN was defined as a right ventricular systolic pressure (RVSP) > 60 mmHg during exercise. Results: At rest, baseline echocardiographic parameters were not different between the two groups. During exercise, mean EROA and regurgitant volume (RV) were markedly increased in patients with PML prolapse compared to those with AML prolapse (ΔEROA, 0.21±0.19 vs 0.05±0.10, P=0.012 and ΔRV 19.4±20.0 vs 3.3±17.5, P=0.030). Moreover, exercise-induced change of RVSP was more significant in PML prolapsed compared with AML prolapsed (ΔRVSP, 42.2±10.5 vs 26.7±8.6, P Conclusion: During exercise, PML prolapsed is associated with more increase of MR severity, more increased RVSP, and more significant LV remodeling compared to the AML prolapsed in patients with moderate to severe degenerative MR.