Metabolic syndrome increases operative mortality in patients undergoing coronary artery bypass grafting surgery

The aim of this study was to determine the impact of the metabolic syndrome (MS) on operative mortality after a coronary artery bypass grafting surgery (CABG).

Diabetes and obesity are highly prevalent among patients undergoing CABG. However, it remains unclear whether these factors have a significant impact on operative mortality after this procedure. We hypothesized that the metabolic abnormalities associated with MS could negatively influence the operative outcome of CABG surgery.

We retrospectively analyzed the data of 5,304 consecutive patients who underwent an isolated CABG procedure between 2000 and 2004. Of these 5,304 patients, 2,411 (46%) patients met the National Cholesterol Education Program-Adult Treatment Panel III criteria for MS. The primary end point was operative mortality.

The operative mortality after CABG surgery was 2.4% in patients with MS and 0.9% in patients without MS (p < 0.0001). The MS was a strong independent predictor of operative mortality (relative risk 3.04 [95% confidence interval (CI) 1.73 to 5.32], p = 0.0001). After adjusting for other risk factors, the risk of mortality was increased 2.69-fold (95% CI 1.43 to 5.06; p = 0.002) in patients with MS and diabetes and 2.36-fold (95% CI 1.26 to 4.41; p = 0.007) in patients with MS and no diabetes, whereas it was not significantly increased in the patients with diabetes and no MS.

This is the first study to report that MS is a highly prevalent and powerful risk factor for operative mortality in patients undergoing a CABG surgery. Thus, interventions that could contribute to reduce the prevalence of MS in patients with coronary artery disease or that could acutely modify the metabolic perturbations of MS at the time of CABG might substantially improve survival in these patients.