Assessing Mitral Regurgitation in Patients with Dilated Cardiomyopathy Using 3.0T Cardiac Magnetic Resonance Imaging: Correlation with Morphological and Functional Abnormalities

Abstract

Background: Mitral regurgitation frequently accompanies dilated cardiomyopathy (DCM), which is associated with poor prognosis. Objectives: To evaluate morphological and functional abnormalities in DCM patients and correlate these features with the severity of coexistent mitral regurgitation using 3.0 T magnetic resonance imaging (MRI). Patients and Methods: Forty-one patients with DCM and 26 healthy control subjects underwent MRI and echocardiography examinations. The maximum and minimum mitral annulus areas (MAA), diameters of left ventricle and atrium, end-diastolic and systolic volumes, and ejection fraction were assessed with MRI and were indexed to body surface area. Mitral regurgitation severity grading was estimated by echocardiography. Results: Of the 41 patients with DCM, echocardiography examination revealed 11 patients (27%) without mitral regurgitation and 12 (29%) with mild, 11 (27%) with moderate, and seven (17%) with severe mitral regurgitation. All of the morphological and functional parameters of left ventricle, atrium and mitral valve in DCM patients were greater than those in healthy subjects (all P < 0.05), except for ejection fraction. The indexed end-systolic diameters of left ventricle (LVESD) and atrium (LAESD) and indexed minimum MAA might have the capability to distinguish no/mild mitral regurgitation patients from moderate/severe patients (areas under the receiver operating characteristic curve [AUC] = 0.876, 0.816, and 0.773, respectively; all P < 0.05). Using a combination of indexed LAESD, LVESD and minimum MAA, the specificity increased to 91.3%. Conclusion: Mitral regurgitation in DCM patients is associated with morphological and functional abnormalities of left heart and mitral valve annulus. The indexed LVESD, LAESD, and minimum MAA values can assist in predicting the severity of mitral regurgitation with a high sensitivity and specificity.