Abstract 16890: Postoperative Atrial Fibrillation Following Coronary Artery Bypass Surgery in Severe Obesity: Impact of Waist Circumference

Abstract

Introduction: Obesity (body mass index (BMI) ≥ 30 kg/m 2 ) is an independent risk factor for postoperative atrial fibrillation (POAF) after coronary artery bypass grafting (CABG) surgery. The incidence of POAF in patients with severe obesity (BMI ≥ 35 kg/m 2 ) is less studied. For a given BMI, higher waist circumference (WC) predicts adverse cardiovascular outcomes. Whether WC predicts POAF independently of BMI among patients with severe obesity remains unknown. Aim: To evaluate the risk of POAF after isolated CABG in patients with severe obesity, and the role of WC in predicting POAF in this population. Methods: Our cohort included 7,995 patients undergoing isolated CABG (2006-19). Patients with atrial fibrillation were excluded. POAF risk was compared across BMI and WC categories. In patients with severe obesity, the association of a 10 cm incremental in WC with POAF risk was assessed. We used a log-binomial regression model. Results are presented as adjusted relative risks (aRR) with 95% confidence intervals (CI). Results: 763 (9.5%) patients had a BMI ≥ 35 kg/m 2 . Mean BMI was 38.5 ± 3.6 kg/m 2 and WC was 123.4 ± 10.8 cm. The severe obesity group was younger (63 ± 9 vs. 67 ± 9 years, p <0.01) and had a higher proportion of females (28 vs. 21%, p <0.01) compared to normal BMI. More patients with severe obesity developed POAF (37 vs. 29%, aRR: 1.52 [95%CI 1.36-1.72], p <0.01). aRRs of POAF according to BMI and WC categories are presented in Table 1. Independently of BMI, every 10 cm increment in WC among patients with severe obesity was associated with an increased risk of POAF (aRR: 1.17 [95%CI 1.09-1.25], p <0.01). Conclusions: POAF after CABG is prevalent in patients with severe obesity. Our results showed a gradient of increasing POAF risk with increasing BMI and WC. In patients with severe obesity, WC independently provided additional prognostic value beyond BMI. Since POAF is associated with adverse long-term outcomes, WC could be targeted for the development of preventive strategies.