Three-Dimensional Assessment of Left Ventricular Geometry and Annular Dilatation Provides New Mechanistic Insights into the Surgical Correction of Ischemic Mitral Regurgitation

Abstract

The aim of this study was to investigate the relationship between LV geometry, annular shape and the amount of regurgitation in patients with ischemic mitral regurgitation (group 1, n = 30) compared to patients with primary mitral valve lesions (group 2, n = 30). LV geometry was assessed by the sphericity index, i.e., LV volume divided by the volume of a sphere with a diameter equal to the longest axis. Annular geometry was evaluated by diameters, areas and their percentual shortening. The degree of mitral regurgitation was assessed as jet volumes by 3D-echocardiography. Group 1 showed significantly larger longitudinal (54.3 +/- 3.1 vs. 40.9 +/- 2.6 mm) and antero-posterior (32.2 +/- 3.3 vs. 27.1 +/- 2.9 mm) annulus diameters and areas (993.3 +/- 66.6 vs. 702.1 +/- 47.9 mm (2)) than group 2. No asymmetric annular enlargement was found in either group. Annular enlargement correlated to the degree of mitral regurgitation in group 1 but not in group 2. Annular area shortening was significantly impaired in group 2 and the sphericity index was larger in group 1 than in group 2. In group 1, the sphericity index was significantly correlated to the degree of mitral regurgitation (r = 0.87; P < 0.001). These findings suggest that ischemic mitral regurgitation was mostly associated with a global left ventricular enlargement, in which annulus dilatation and its reduced contraction play a significant role.