Long-term influence of mild or moderate ischemic mitral regurgitation after off-pump coronary artery bypass surgery.

Abstract

BACKGROUND The issue of mild to moderate ischemic mitral regurgitation (IMR) is controversial after conventional surgery, and has not been specifically studied after off-pump coronary artery bypass graft (OPCAB) surgery. OBJECTIVE To review the influence of mild or moderate IMR on longterm survival and recurrent cardiac events after OPCAB surgery. METHODS A total of 1000 consecutive and systematic OPCAB patients who underwent operations between September 1996 and March 2004 were prospectively followed. Sixty-seven patients (6.7%) had mild to moderate IMR at the time of surgery. Operative mortality, actuarial survival and major adverse cardiac event-free survival were studied to assess the effect of IMR. RESULTS The mean (+/- SD) follow-up period was 66+/-22 months and was completed in 97% of the cohort. IMR patients were older (P<0.001), and had lower ejection fractions (P<0.001) and more comorbidities. More female patients presented with IMR (P=0.002). Operative mortality (P=0.25) and prevalence of perioperative myocardial infarction (P=0.25) were comparable for both groups. Eight-year survival was decreased in IMR patients (P<0.001), but after adjusting for risk factors in the Cox regression model, mild to moderate IMR was not found to be a significant risk factor of long-term mortality (P=0.42). Major adverse cardiac event-free survival at eight years was significantly lower in IMR patients (P<0.001) and, more specifically, in patients with 2+ IMR. After adjusting for risk factors, IMR remained a significant cause of poor outcome (hazard ratio 2.09), especially for recurrent congestive heart failure and myocardial infarction. CONCLUSIONS OPCAB patients with preoperative mild or moderate IMR had a higher prevalence of preoperative risk factors than those without IMR. They had comparable perioperative mortality and morbidity but, over the long term, were found to be at risk for recurrent cardiac events.