Prognostic Indices after Mitral Valve Replacement in Patients with Chronic Mitral Regurgitation

Ryu, Kyu Hyung; Oh, Byung Hee; Park, Young Bae; Choi, Yun Shik; Seo, Jung Don; Lee, Young Woo

Abstract

Chronic mitral regurgitation may be well tolerated for decades because of favorable conditions like increased preload and decreased afterload. However, in some patients with underlying overt myocardial dysfunction, opertive correction of mitral regurgitation may result in persistent left ventricular dysfunction. Myocardial dysfunction in mitral regurgitation initially occurs subclinically and may becoma irreversible before symptoms of congestive heart failure develop. In order to identify latent myocardial dysfunction, we evaluated prognostic values of several indices from patient's characteristics, echocardiogram, cardiac catheterization data and contrast left ventriculogram in 49 patients with chronic mitral regurgitation who received mitral valve replacement. The patients were defined as Groups I who had improved symptoms with decreased left ventricular end-diastolic dimension after operation and Group II who had persistent symptoms and progressed left ventricular end-diastolic dimension, or not decreased until left ventricular end-diastolic dimension 60mm after operation. The results were as follows: 1) There was no significant difference in age, sex, duration of symptoms, preoperative NYHA functional status, and aortic cross clamping time during operation between Group I and Group II. 2) There was no significant difference in echocardiographic left ventricular end-diastolic dimension between group I and group II. There were significantly more dilated left ventricular end-diastolic dimension of Group II than that of Group I and significantly more depressed fractional shortening of Group II than that of Group I. There was significantly more increased end-diastolic wall stress of Group II than of Group I. 3) There was no significant difference in cardiac index, mean pulmonary artery pressure, mean pulmonary capillary wedge pressure and left ventricular end-diastoic pressure between Group I and Group II. 4) There were significantly more increased end-diastolic volume index and end-diastolic volum index of Group II than those of Group I, but no significant difference in ejection fraction between Group I and Group II. There was significantly more decreased ratio of end-diastolic circumferential midwall stress to end-diastolic volume index of Group II than that of Group I. 5) In Group I, end-systolic dimension, end-systolic dimension and end-systolic wall stress were decreased significantly after operation. In Group II, end-systolic dimension was decreased significantly after operation. 6) Values for combination of end-systolic left ventricular dimension greater than 28mm/m2 and end-systolic wall stress greater than 190mmHg predicted a Group II outcome with a sensitivity of 88.2%, a specificity of 93.8%, positive predictive value of 88.2% and negative predictive value of 93.8%. Values of combination of end-systolic left ventricular dimension greater than 28mm/m2 and fractional shortening less than 32% predicted a Group II outcome with a sensitivity of 88.2% a specificity of 90.6%, positive predictive value of 83.3% and negative predictive value of 93.5%, a specificity of 90.6%, positive predictive valve of 83.3% and negative predictive value of 93.5%. According to the above results, noninvasive hemodynamic variables such as end-systolic left ventricular dimension, fractional shortening and end-systolic wall stress would be useful guideline for follow-up and determining the optimal time for surgical intervention in patients with chronic mitral regurgitation.