Ischemic Mitral Regurgitation

Abstract

Ischemic mitral regurgitation (MR) is defined as functional MR caused by myocardial ischemia. Apical and posterior displacement of papillary muscles , referred to as tethering, positively correlates with maximal regurgitation area. Surgical intervention for patients with moderately ischemic MR at the time of coronary artery bypass (CABG) remains controversial. However, patients with uncorrected mild or moderate MR who undergo CABG are at increased risk of death and hospitalization. Restrictive MV annuloplasty and coronary artery bypass surgery has become accepted as the standard technique for severe functional MR. However, even after downsizing simple annuloplasty by two sizes, MR persists or recurs in >20% of patient. Furthermore, recurrent and progressive MR after MV plasty is associated with high mortality rates. Predictors for recurrent mitral regurgitation are flexible ring usage, left ventricle diameter, continuous LV remodeling, sphericity index at end-systole and end-diastole, and preoperative posterior leaflet angle >45°. Second chordal cutting, papillary muscle approximation and so on are recommended as additional procedures. Whether to replace or repair severe chronic ischemic MV regurgitation has remained controversial. Replacement results in long-term secure MV sufficiency, whereas mitral repair still confers some risk of MR recurrence. Percutaneous MV repair using the MitraClip procedure can offer clinical improvement even in patients with high surgical risk and severe functional MR. The long-term outcomes of the this procedure should be determined. Ischemic MR remains a significant complication of myocardial infarction, and deeper understanding of the mechanism of ischemic MR has led to continuous improvements in surgical treatment. Complex mechanisms involving the mitral annulus, chordae tendinea, papillary muscle, and LV are involved, and optimal surgical repair should consider the overall pathology of each patient.