Impact of body mass index on outcome in patients undergoing coronary artery bypass grafting and/or valve replacement surgery

OBJECTIVE This study aimed to analyze the impact of body mass index on outcomes of 101 patients undergoing coronary artery bypass grafting, valve replacement, or combined valve/ coronary artery bypass grafting surgery in a private hospital in Belo Horizonte, Brazil. METHODS This was a prospective cross-sectional study of patients undergoing cardiac surgery from May 2009 to December 2012. All patients were followed up from the first day of admission until discharge or death. Patients were divided into three groups according to BMI: normal weight, overweight, and obese. The main outcome measure was the association between BMI and postoperative morbidities and mortality. RESULTS Multivariate analysis identified obesity as an independent predictor of increased risk of surgical reintervention (odds ratio [OR] 13.6; 95%CI 1.1 - 162.9; P=0.046) and reduced risk of bleeding (OR 0.05; 95% CI 0.09 - 0.69; P=0.025). Univariate analysis showed that obesity was associated with increased frequency of wound dehiscence (P=0.021). There was no association between BMI and other complications or mortality in univariate analysis. There was also no association between body mass index and duration of cardiopulmonary bypass, aortic clamping, mechanical ventilation, and intensive care unit or hospital stay. CONCLUSION Obese individuals undergoing coronary artery bypass grafting, valve replacement, or combined surgery have a higher postoperative risk of surgical reintervention and lower chances of bleeding.