O efeito do índice de massa corporal sobre as complicações no pós-operatório de cirurgia de revascularização do miocárdio em idososThe effect of the body mass index on postoperative complications of coronary artery bypass grafting in elderly Abstract Objectives: To evaluate the effect of BMI (body mass index) in the postoperative period of elderly patients undergoing CABG.Methods: Cross-sectional retrospective study, carried out in academic hospital, with all patients (n=290), aged or above 60 years, undergone CABG, from August 2006 to July 2007. The patients were divided into tertiles of BMI (<22, 22-27,> 27kg /m²). The variables included in the study were collected from medical records of patients and analyzed by logistic regression in association with the categories of BMI.Results: In the group with malnutrition were found larger percentage of impaired lung, kidney, hospital stay and immediate surgical mortality; but without statistical significance. Among female patients, the group malnutrition and eutrophy, 61.5% had hospital stay for a period longer than seven postoperative days compared to 42.5% male patients (p=0.003). In the group with malnutrition was found association between the CPB time and renal dysfunction with p<0.001 and, in eutrophic group with p=0.04. Obesity obtained protective association for lung dysfunction (RR=0.99), readmissions (RR=0.45) and mortality (RR = 0.77), and risk factor for renal dysfunction (RR=1.12). Conclusions 525REIS, C ET AL -The effect of the body mass index on postoperative complications of coronary artery bypass grafting in elderly Bras Cir Cardiovasc 2008; 23(4): 524-529 Rev