Annular geometry in patients with chronic ischemic mitral regurgitation: three-dimensional magnetic resonance imaging...

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.

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 (> or =2+, n=15 versus < or =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).

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.