Isolated Coronary Artery Bypass Grafting in Obese Individuals - A Propensity Matched Analysis of Outcomes

Background: There is conflicting data regarding the impact of obesity on morbidity and mortality in patients undergoing isolated coronary artery bypass grafting (CABG). Methods and Results: Retrospective cohort analysis of patients who underwent CABG from January 1, 1995, through July 31, 2010 was performed. Patients were classified as obese or non-obese (body mass index >= 30.0 kg/m(2) and <30.0 kg/m(2), respectively). The primary outcome was in-hospital mortality. Secondary outcomes included postoperative respiratory failure, postoperative stroke, postoperative myocardial infarction, sternal and leg wound infections, postoperative atrial fibrillation, postoperative ventricular tachycardia, postoperative renal failure and length of hospital stay. Propensity-matched stepwise multivariable logistic regression was performed. Of 13,115 patients, 4,619 (35.2%) were obese. In the propensity-matched logistic regression models (n=8,442), obesity was not associated with postoperative mortality (odds ratio=1.13, 95% confidence interval 0.86-1.48). However, obesity was associated with postoperative respiratory failure, postoperative renal insufficiency, sternal wound infection, and leg wound infection. Obesity was also associated with a decreased risk of postoperative bleeding and re-operation from bleeding. Conclusions: Obesity was associated with an increased risk of postoperative respiratory failure, postoperative renal failure, and surgical site infections. However, obesity was not associated with in-hospital mortality in patients undergoing CABG. (Circ J 2011; 75: 1378-1385)