Surgical treatment of the ischemic mitral valve

The best management for moderate mitral regurgitation (MR) at the time of coronary revascularization remains controversial. During the era preceding standardization of mitral annuloplasty, coronary artery bypass grafting (CABG) alone was the most common strategy for ischemic MR. This approach avoided mitral valve replacement, and there was an expectation that myocardial revascularization would improve papillary muscle function and valve performance. Long-term follow up revealed, however, a relationship between residual MR and mortality. Recent studies have further refined management of ischemic MR. It is now understood that Carpentier type IIIb dysfunction is the basis for ischemic MR, and that a reduction remodeling annuloplasty can improve leaflet coaptation in this setting. Mortality after combined CABG and mitral annuloplasty has decreased in our institution from 14% to 4% over the past decade. Furthermore, a strategy of CABG alone will leave a significant number of patients (approximately 40%) with moderate to severe MR. Our current approach is to explore all valves at the time of CABG with documented grade 3+ MR on preoperative transthoracic echocardiography. Intraoperative transesophageal echocardiography (TEE) underestimates moderate MR. In patients with a lesser degree of MR, intraoperative provocative testing guides our valve strategy. Severe left ventricular dysfunction and a history of congestive heart failure will also influence the decision regarding valve exploration at the time of CABG. A prospective randomized trial between CABG and CABG + mitral annuloplasty is necessary to further define the best management strategy for patients with moderate ischemic MR.