Metabolic Syndrome Affects Midterm Outcome After Coronary Artery Bypass Grafting

Background. Metabolic syndrome (MetS) is frequently associated with coronary artery disease, but data on the impact of MetS on long-term outcome of patients undergoing coronary artery bypass grafting are still lacking. The aim of the present study was to assess the effect of MetS on mortality and morbidity late after coronary artery bypass grafting. Methods. A total of 1,726 consecutive patients who had elective coronary artery bypass grafting were retrospectively reviewed and clinical follow-up was completed (mean follow-up time, 34.4 months; range, 6 to 79 months). The MetS was diagnosed using the modified Adult Treatment Panel III criteria, and to eliminate covariate differences, a propensity score adjustment was used. Major adverse cerebral and cardiovascular events were investigated, and C-reactive protein levels were assessed both preoperatively, postoperatively, and at follow-up. Results. A total of 798 of 1,726 patients (46.2%) met the diagnostic criteria for MetS. At follow-up, all-cause mortality (7% versus 4.6%; p = 0.04), cardiac arrhythmias (35.3% versus 25.2%; p < 0.0001), renal failure (12% versus 8.7%; p = 0.03), and major adverse cerebral and cardiovascular events (52.4% versus 39.5%; p < 0.0001) showed a significantly higher incidence in MetS patients. Variables correlated with late mortality at propensityadjusted Cox proportional-hazards regression were age (p = 0.0008), preoperative left ventricular ejection fraction (p = 0.001), preoperative renal failure (p = 0.001), and MetS (p = 0.006). Higher C-reactive protein levels were found preoperatively (8.6 +/- 2.3 versus 5.14 +/- 3.1 mg/L; p < 0.0001) and both early (71.2 +/- 9 versus 49.6 +/- 8.7 mg/L; p < 0.0001) and late (7.4 +/- 2.7 versus 4.8 +/- 2.5mg/L; p < 0.0001) after surgery. Conclusions. The main finding of our study was the association between MetS and mortality both early and late after coronary artery bypass grafting. Thus, MetS should be recognized as an independent preoperative variable that can lead to the identification of high-risk patients and as a risk factor to correct with lifestyle modifications and pharmacologic therapy. (Ann Thorac Surg 2012;93:537-44) (C) 2012 by The Society of Thoracic Surgeons