Abstract 19311: Obesity is Associated with Increased Rates of Revascularization in Coronary Artery Bypass Grafting Patients: A Large Cohort Study

Abstract

Introduction: While excess mass has been demonstrated to be associated with improved survival in subjects with coronary artery disease (CAD), other potential outcomes have not been considered. The objective of this study was to assess the relationship between obesity and repeat revascularization in subjects who have undergone coronary artery bypass grafting (CABG).

METHODS: The Alberta Provincial Project for Outcomes Assessment in Coronary Heart Disease database was used to obtain information on subjects who underwent CABG between 1995 and 2010. Subjects were classified as normal weight (BMI 18.5-24.9), overweight (25-29.9), obese class I (30-34.9), obese class II (35-39.9), or obese class III (≥40 kg/m2). Outcome of interest was time to repeat revascularization: the 1st percutaneous coronary intervention or CABG after index CABG. Cox proportional hazard models were used to determine the association between adiposity and freedom from repeat revascularization. Results: There were 13416 subjects included in this study, 23% normal weight. The more obese subjects were younger and had a higher prevalence of diabetes (p<0.0001 across categories). Median follow-up time was 6.3 years; there were 1029 subjects who underwent repeat revascularization. In unadjusted models BMI was associated with increased revascularization (overweight Hazard Ratio (HR), 1.22, 95%CI 1.03, 1.45; Obese Class I 1.22, 95%CI 1.01, 1.48; Obese Class II/III 1.60, 95%CI 1.28, 2.00). This association persisted following adjustment for sex, age and clinical characteristics in overweight (HR 1.20, 95%CI 1.01, 1.42) and obese class II/III subjects (HR 1.41, 95% CI 1.12, 1.77). Discussion: Despite improved survival in obese subjects with CAD, we found obesity is associated with an increased risk of revascularization. This may represent elevated residual risk in obese patients. This finding is novel, and highlights the need to pay particular attention to residual risk in obese subjects with CAD.