Predictors of post-operative atrial fibrillation in patients undergoing cardiac surgery: the potential role of epicardial adipose tissue

Abstract

Background: Post-operative atrial fibrillation (POAF) is a common complication following cardiac surgeries, however current risk factors lack predictive accuracy. Our aim was to investigate whether computed tomography (CT) measurement of epicardial adipose tissue (EAT) improves risk prediction over clinical predictors of POAF. Methods: Fifty-six patients who underwent aortic valve replacement (AVR) and/or coronary artery bypass graft (CABG) during 2013 to 2015 were identified retrospectively. Peri-operative clinical characteristics were collected, and epicardial fat dimensions were measured using CT. Results: POAF occurred in 27 patients (48.2%). The incidence of POAF was greater in patients undergoing CABG with or without AVR compared to AVR alone (64% vs. 32%, P=0.018). Univariate logistic regression model showed CHA2DS2-VASc score [odds ratio (OR): 1.629; 95% CI: 1.086–2.443; P=0.018] and EuroSCORE II (OR: 1.528; 95% CI: 1.006–2.320; P=0.047) to be significantly associated with POAF. Between-group analysis showed left atrial (LA) diameter was significantly associated with POAF compared to no-POAF (4.18±0.74 vs. 3.74±0.36 cm; P=0.047). The sum of right coronary artery fat pocket and inferior interventricular (IV) groove was higher in POAF patients (7.75±1.70 vs. 6.87±2.27; P=0.05). A novel scoring system comprising EuroSCORE II, CHA2DS2-Vasc and LA diameter was created which was significantly associated with POAF risk compared to CHA2DS2-Vasc alone (receiver operator curve AUC 0.804; 95% CI: 1.162–15.180; P=0.029). However, adding EAT to the POAF scoring system did not improve the risk prediction model for POAF (AUC 0.79; 95% CI: 1.083–12.998; P=0.037). Conclusions: A novel POAF prediction scoring system including LA diameter, EuroSCORE II and CHA2DS2-Vasc was strongly associated with POAF and may be a useful clinical tool when planning cardiac surgery. Addition of EAT did not improve risk prediction beyond clinical predictors. Further large-scale studies are required to assess the validity and usefulness of the scoring system.