Importance of moderate ischemic mitral regurgitation

The importance of moderate ischemic mitral regurgitation in patients presenting for coronary artery bypass grafting (CABG) is controversial. Therefore, we tracked the course of unrepaired moderate ischemic mitral regurgitation after CABG surgery alone, identified factors associated with worsening postoperative ischemic mitral regurgitation, and assessed the impact of unrepaired moderate ischemic mitral regurgitation on survival.

From 1980 to 2000, 467 patients with moderate ischemic mitral regurgitation underwent CABG alone. The course of unrepaired mitral regurgitation was estimated by a longitudinal analysis of 267 follow-up echocardiograms from 156 patients. The survival impact of moderate ischemic mitral regurgitation was determined among propensity-matched patients with and without ischemic mitral regurgitation.

Mitral regurgitation was dynamic early postoperatively. Immediately postoperatively, it was absent or mild in 73% and severe in 6%; by 6 weeks, these figures were 40% and 22%, respectively. The course of postoperative mitral regurgitation was not associated with the preoperative extent of coronary artery disease or left ventricular dysfunction. Five-year survival of matched bypass patients without ischemic mitral regurgitation was 85% compared with 73% for patients with moderate ischemic mitral regurgitation (p = 0.003).

Moderate ischemic mitral regurgitation does not reliably resolve with CABG surgery alone and is associated with reduced survival. Therefore, a mitral valve procedure may be warranted for such patients presenting for CABG. A randomized trial comparing strategies of revascularization with mitral valve repair and revascularization alone is required to determine optimal treatment.