Clinical Results of Mitral Valvular Surgery in Patients with Moderate Ischemic Mitral Regurgitation Undergoing Coronary Artery Bypass Grafting

Background: There have been controversies whether mitral valvular surgery is necessary in the patients with moderate ischemic mitral regurgitation undergoing coronary artery bypass grafting. The purpose of this study is to evaluate the long term clinical results of patients with moderate ischemic mitral regurgitation. Material and Method: Between January 1992 and February 2005, 44 patients with moderate ischemic mitral regurgitation underwent coronary artery bypass grafting. Concomitant mitral valvular procedure was performed in 20 patients (group 1) and isolated coronary artery bypass grafting was performed in 24 patients (group 2). There were no significant difference between groups except cardiopulmonary bypass time (p＜0.01). Postoperative follow up duration was 30.1±29.6 months and last follow up echocardiographic examination was performed at 21.2±28.0 months. Result: There was no difference in operative mortality between groups (group 1 vs group 2, 15.0% vs 8.3%, p=0.493). Grade of mitral regurgitation (0.81±0.91 vs 1.50±0.05, p=0.046) and reduction in regurgitation grade (1.75±0.93 vs 0.70±1.26, p=0.009) were different between two groups. But there were no significant differences in left ventricular ejection fraction (34.1±11.4% vs 41.6±12.9%), left ventricular end systolic volume (118.2±63.9 mL vs 85.6±28.1 mL), New York Heart Association functional class (2.1±0.2 vs 2.4±1.2) and 5 year survival rate (85±8% vs 82±8%). There was no risk factor for operative mortality and the only risk factor for late death was preoperative atrial fibrillation (p=0.042). There was no significant correlation between mitral valvular surgery and late death. Conclusion: Concomitant mitral valvular procedure in patients with moderate ischemic mitral regurgitation undergoing coronary artery bypass grafting had no significant positive effect on survival and ventricular function compared with isolated coronary artery bypass grafting. Prospective randomized study may be needed to evaluate the necessity of concomitant mitral procedure and to find more effective method for the improvement of ventricular function.ope