Patients with metabolic syndrome are nearly three times as likely to die following coronary artery bypass graft surgery as are patients without the syndrome, according to a large study.
Patients with both metabolic syndrome and diabetes had a 2.7-fold increase in the risk of mortality, and patients with metabolic syndrome but without diabetes had a 2.4-fold increase in risk. In the multivariate analysis, there proved to be no significant increase in the risk of mortality in patients who had diabetes but not metabolic syndrome, wrote Dr. Najmeddine Echahidi of the Centre de Recherche de l'Hôpital Laval, Quebec, and colleagues (J. Am. Coll. Cardiol. 2007;50:843–51).
The retrospective analysis involved 5,304 consecutive patients who underwent an isolated coronary artery bypass graft (CABG) between 2000 and 2004 at a single institution. An analysis of prospectively collected laboratory and physical data revealed that 46% met criteria for metabolic syndrome as set out by the National Cholesterol Education Program Adult Treatment Panel III.
The study's primary end point was death from any cause, either within 30 days of surgery or after any interval if the patient was not discharged from the hospital. Results were adjusted for gender, peripheral vascular disease, chronic obstructive pulmonary disease, preoperative renal failure, preoperative myocardial infarction, and preoperative stroke.
The overall unadjusted mortality was 1.6%, but was significantly higher (2.4%) among patients with metabolic syndrome, and significantly lower (0.9%) among patients without metabolic syndrome.
In addition to metabolic syndrome, several other factors increased the risk of mortality following CABG. These included age older than 75 years (relative risk 3.4), body mass index (kg/m
Considering the prevalence of metabolic syndrome, the investigators suggested that patients be assessed for metabolic syndrome before surgery, and that metabolic syndrome be incorporated into operative risk algorithms.