Effect of Body Mass Index on Morbidity and Mortality in Patients Undergoing Coronary Artery Bypass Grafting

Abstract

Background: Obesity affects cardiovascular morbidity and mortality, and it increases the risk of coronary artery disease. Despite that, several cardiac surgery risk stratification scores do not consider the effect of obesity on the outcomes. The objective of this research is to study the impact of body mass index (BMI) on morbidity and mortality after coronary artery bypass grafting (CABG) in Egyptian patients.

Methods: This prospective cohort study included 200 patients who underwent CABG for atherosclerotic coronary artery disease. Patients were divided into two groups, group A: patients with BMI ≥ 25 Kg/m2 and group B: patients with BMI < 25 Kg/m2. The mean age in group A was 56± 4.95 years vs. 54± 5.5 years in group B (p= 0.102). Male patients presented 58% of the population in group A vs 74% in group B (p= 0.017). 60% of patients were hypertensive in group A compared to 63% in group B (p= 0.66) and 62%, and 48% were diabetics in group A and B respectively (p= 0.04).

Results: Postoperatively, there was a significant increase in wound infection (40% vs 8%; p< 0.001), chest infection (47% vs. 10% p< 0.001), surgical re-exploration (28% vs. 1%; p< 0.001), prolonged ICU stays (5.3 ± 2.88 vs. 3.93 ± 1.71 days; p< 0.001), ward stay (11.28 ±8.9 vs. 5.48 ± 2.45 days; p< 0.001), mediastinitis (34% vs. 6%; p< 0.001), the occurrence of sternal wound sinus within 8 months (26% vs. 7%; p< 0.001), in group A more compared to group B. There was no difference in ejection fraction (54.2 ±7.38 vs. 54.7 ± 9.1%; p= 0.69) and mortality (4% vs. 2%; p= 0.68) between groups.

Conclusions: BMI 25 Kg/m2 or higher is associated with increased infectious complications and prolonged stay after CABG; however, it did not affect mortality. Optimizing body weight is recommended before elective surgery.