Etiologic Evaluation of Ischemic Mitral Regurgitation Using Cardiac MRI

Background and Objectives：To evaluate the 3 dimensional geometric changes and the effect of revasculari-zation in patients with ischemic mitral regurgitation (IMR), using cardiac magnetic resonance imaging (MRI). Subjects and Methods：Twenty-three patients with IMR, 10 with dilated cardiomyopathy with MR (DCM-MR) and 7 control subjects were enrolled. Hemodynamic indices, severity of MR, geometric parameters of mitral apparatus and myocardial viability were evaluated in all patients, and re-evaluated in the IMR patients 6 months after the revascularization. Results：The mitral tenting area (TAA) (334.1±111.7 mm2 vs. 222.9± 123.0 mm2, p=0.16) and the sum of the tenting angles (TA) (72.9±12.9°vs. 51.5±11.1°, p<0.001) at the mid-sys-tolic phase were increased in the IMR compared to the DCM-MR patients. In the IMR patients, the MR se-verity was positively correlated with the sum of the tethering lengths (r=0.522, p=0.011), LVESV (r=0.551, p= 0.006), TAA (r=0.613, p=0.002) and TA (r=0.713, p<0.001). Of the 10 patients with viable myocardium, who had been revascularized without surgical repair of the mitral apparatus, the MR severity was decreased (28.3±10.4% vs. 16.5±7.6%, p=0.009) in 7 patients, with decreases in the sum of the tethering distances (51.2±13.9 mm vs. 40.2±9.1 mm, p=0.034), tenting area (299.2±93.8 mm2 vs. 215.0±63.6 mm2, p=0.036) and sum of the tenting an-gles (72.9±12.9 ° vs. 56.2±14.8°, p=0.015) 6 months after the revascularization. Conclusion：IMR was related