Echocardiographic evaluation of mitral geometry in functional mitral regurgitation

OBJECTIVES: We sought to evaluate the geometric changes of the mitral leaflets, local and global LV remodeling in patients with left ventricular dysfunction and varying degrees of Functional mitral regurgitation (FMR). BACKGROUND: Functional mitral regurgitation (FMR) occurs as a consequence of systolic left ventricular (LV) dysfunction caused by ischemic or nonischemic cardiomyopathy. Mitral valve repair in ischemic MR is one of the most controversial topic in surgery and proper repairing requires an understanding of its mechanisms, as the exact mechanism of FMR are not well defined. METHODS: 136 consecutive patients mean age of 55 with systolic LV dysfunction and FMR underwent complete echocardiography and after assessing MR severity, LV volumes, Ejection Fraction, LV sphericity index, C-Septal distance, Mitral valve annulus, Interpapillary distance, Tenting distance and Tenting area were obtained. RESULTS: There was significant association between MR severity and echocardiogarphic indices (all p values < 0.001). Severe MR occurred more frequently in dilated cardiomyopathy (DCM) patients compared to ischemic patients, (p < 0.001). Based on the model, only Mitral valve tenting distance (TnD) (OR = 22.11, CI 95%: 14.18 – 36.86, p < 0.001) and Interpapillary muscle distance (IPMD), (OR = 6.53, CI 95%: 2.10 – 10.23, p = 0.001) had significant associations with MR severity. Mitral annular dimensions and area, C-septal distance and sphericity index, although greater in patients with severe regurgitation, did not significantly contribute to FMR severity. CONCLUSION: Degree of LV enlargement and dysfunction were not primary determinants of FMR severity, therefore local LV remodeling and mitral valve apparatus deformation are the strongest predictors of functional MR severity.