Annular Geometry in Patients With Chronic Ischemic Mitral Regurgitation

Abstract

Background— Although animal studies showed that annular remodeling may be related to the pathogenesis of chronic ischemic mitral regurgitation (CIMR), little was known in humans. A better understanding of the precise 3D geometry of the mitral valvular-ventricular complex in CIMR is needed to devise a better surgical technique. The purpose of the study was to elucidate mitral annular geometry in patients with CIMR using cardiac MRI. Methods and Results— Thirty-eight patients with previous inferior or posterior myocardial infarction were studied. With the 3D reconstruction of the mitral annulus and subvalvular apparatus from a series of longitudinal cine MRIs, end-systolic mitral annulus dimensions and 3D geometry were calculated. Patients were grouped by mitral regurgitation grade using echocardiography (≥2+, n=15 versus ≤1+, n=23). Both septal-lateral and commissure-commissure mitral annular diameters were significantly greater in CIMR(+) patients (35±5 versus 30±4 mm, P =0.005; 46±6 versus 39±4 mm, P <0.001, respectively). The length of the fibrous annulus was significantly larger in CIMR(+) patients (28±3 versus 24±3 mm; P <0.001). The height of the annular “saddle horn” above a best-fit plane was lower in CIMR(+) patients (4.2±1.2 versus 6.0±1.8 mm; P =0.002), and the annular height to commissural width ratio was significantly lower in CIMR(+) patients (12±3 versus 21±5%; P <0.001). Conclusions— Patients with CIMR had greater septal-lateral and commissure-commissure mitral annular dimension, larger intertrigonal distance, and flattened saddle shape of mitral annulus. These associated geometric alterations may be important in the pathogenesis of CIMR.