Improved functional mitral regurgitation after off-pump revascularization in acute coronary syndrome.

Background: We evaluated the effect of isolated off-pump coronary artery bypass grafting on functional ischemic mitral regurgitation (IMR) associated with acute coronary syndrome.

Methods: Of 1,419 acute coronary syndrome patients who underwent coronary revascularization between 2000 and 2010 (1,324 off-pump and 95 on-pump), 59 OPCAB patients had greater than mild degree functional IMR preoperatively (31 mild to moderate, 23 moderate, 5 severe). Clinical outcomes and results from echocardiography, angiography, and myocardial single-photon emission computed tomography performed early and 1 year postoperatively were analyzed.

Results: Operative mortality was 5.1% (3 of 59). All survivors underwent early postoperative echocardiograms, which showed 0 patients with worsened IMR; 41 with less than or equal to mild degree residual IMR (NMR group); and 15 with greater than mild degree IMR (RMR group). Myocardial single-photon emission computed tomography revealed that RMR patients had more reversible ischemic myocardial segments preoperatively than NMR patients (p=0.009). Successful right coronary revascularization with proven graft patency was a predictor of early improvement of IMR (p=0.024). There were no differences in postoperative morbidities between the 2 groups. One-year follow-up echocardiograms demonstrated further improvement in 10 of 13 RMR patients. No patients experienced mitral valve-related events during follow-up. Overall survival and major adverse cardiac event-free survival rates at 5 years were 84.6% and 78.1%, respectively, with no intergroup differences.

Conclusions: Most functional IMR associated with acute coronary syndrome, including severe degree IMR, improved during the first postoperative year after off-pump coronary artery bypass grafting.