Ischemic mitral regurgitation: when and how should it be corrected?

Abstract

True and significant ischemic mitral regurgitation affects on average 4% of the patients undergoing coronary bypass surgery. It not corrected, it profoundly influences the hospital mortality and the five year survival, even in the case of satisfactory myocardial revascularization. It is found predominantly in cases of right coronary and/or circumflex disease, and results mostly from restricted leaflet motion rather than from prolapse. Mitral annulus dilatation is present in all cases, and is the only mechanism of regurgitation in 50% of the patients. The indication for a valve procedure usually rests on findings at heart catheterization (i.e. the ratio of regurgitant/forward stroke volume, LV end-systolic volume index), but may be refined by pre- and perioperative transesophageal echocardiography; the LV volume loading test is very helpful in taking the decision in case of moderate or intermittent regurgitation. Mitral valve annuloplasty will easily and expeditiously correct or decrease the regurgitation in the majority of cases. If the mitral valve has to be replaced, the surgeon should always try to keep the papillary muscle-annulus continuity, at least posteriorly.