Periprocedural Risk Predictors and Body Mass Index Impact Long-Term Prognosis in Patients Undergoing Coronary Artery Bypass Grafting

Objective: The main goal of this study is to identify risk predictors for all-cause mortality in patients undergoing Coronary Artery Bypass Grafting (CABG) based on Body Mass Index (BMI). Methods: All consecutive 4,871 patients undergoing isolated CABG between 2005 and 2021, were included in the study. Underweight (<19 kg/m2 ) (n=42), normal/obese (BMI= 19-39.9 kg/m2 ) (n=4,622), and morbidly obese (BMI ≥ 40 kg/m2 ) (n=215) patients were compared for preoperative characteristics. A propensity-adjusted analysis was used to compare the groups. Primary outcome were long-term incidence of death and Major Adverse Cardiovascular and Cerebrovascular Events (MACCE). Results: Preoperatively, mean age was 71.2 (normal/obese), vs. 75.5 (underweight) vs. 65.9 (morbidly obese) years old. Intraoperatively, morbidly obese patients had higher operating room time. Postoperatively, morbidly obese, and underweight patients had higher blood product transfusion and 30-day readmission rate. Primary outcome of all-cause mortality was normal/obese 528/4622 (11.3%) vs. underweight 11/42 (26.2%) vs. morbidly obese 32/215 (14.9%), p=0.003. MACCE was significantly higher in morbidly obese patients 17/215 (7.9%), p=0.024. Predictors for all-cause mortality in morbidly obese patients were non-white patients, diabetes, Peripheral Vascular Disease (PVD), STS ≥ 4%, dialysis, hypertension, Chronic Obstructive Pulmonary Disease (COPD), Ejection Fraction (EF) <50%, and Atrial fibrillation (Afib). Predictors for all-cause mortality in underweight patients were male gender, white race, STS ≥ 4%, dialysis, EF<50%, and hypertension. Conclusion: Death rate in underweight patients was two-fold compared to normal/obese patients and 57% higher compared to morbidly obese patients. MACCE rate was significantly higher in morbidly obese patients.