Effects of body mass index on early outcome of coronary artery bypass surgery.

Aim: Obesity is commonly thought to be a risk factor for morbidity and mortality after cardiac surgery. The aim of the present study is to evaluate the effects of variations in body mass index on in-hospital outcome of coronary artery bypass grafting (CABG).

Methods: The authors conducted a retrospective review of 10191 consecutive patients who had undergone isolated CABG at the center from February 2002 to November 2006. Patients were divided into four groups according to Body Mass Index (BMI). Underweight patients (BMI<18.5 kg/m(2)) were assigned to group 1 and obese patients (BMI 30 kg/m(2)) were put into group 4. Patients with normal BMI and those who were overweight were placed in group 2 and 3 respectively.

Results: Analysis of the BMI groups showed: of 10191 patients 0.7% was underweight; 31.2% of cases had normal BMI, 47.1%; overweight and 21.0% were obese. Compared with other groups, the members of the obese group were younger, included more women and were more likely to have all the risk factors for coronary artery disease except for cigarette smoking (P<0.0001). The underweight patients had an excess of left main coronary artery disease, previous history of myocardial infarction. In-hospital mortality did not show any difference between groups (P=0.46). There was a significant increase in postoperative gastrointestinal complications among the underweight group in comparison with other groups (P=0.027).

Conclusions: According to this study, obese patients undergoing CABG are not at a greater risk of perioperative death and other adverse outcomes compared to normal weight. After CABG, underweight patients are at higher risk of developing gastrointestinal complications compared to normal patients.