Is epicardial adipose tissue, quantified before cardiac surgery by computed tomography, able to predict postoperative atrial fibrillation?

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: Postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery (CS) associated with prolonged hospitalization and increased risk of future adverse events. Epicardial adipose tissue (EAT), defined as adipose tissue between the myocardium and the visceral pericardium, has been recently recognized as a potential contributor to AF pathogenesis. PURPOSE: to evaluate the role of EAT, measured by preoperative CT, in predicting the occurrence of POAF after CS. METHODS: All patients without prior AT/AF history who underwent CS at our centre were prospectively enrolled and retrospectively analyzed. All the included patients had performed a cardiac CT for the evaluation of the pre-operative coronary arteries. Baseline and surgical characteristics were systematically collected along with pre-operative echocardiographic parameters (LA diameter and area; EF) and CT EAT values. For the evaluation of the EAT we selected the area delimited superiorly from the center of the right pulmonary artery and inferiorly to the end of the pericardial sac. The adipose tissue between the myocardium and the pericardium was manually delimited and the total EAT volume was expressed in mL (total EATV; Fig. 1). Also the thickness (mm) of the EAT at the level of the free wall of the right ventricle (RV EAT) and posterior to the left atrium in a 4-chamber plane (LA EAT) were reported. All the measured EAT were indexed for BSA. Multivariate logistic regression analysis was used to identify independent predictors of the study endpoint: the occurrence POAF during the early postoperative period. RESULTS: A total of 117 patients (age 65±15 years old; M= 71%) were enrolled. Soon after surgery, POAF was observed in 55 patients (47%). Patients with POAF were significantly older, with higher comorbidities burden (diabetes; CHA2DS2-VASc score ≥1) than patients without POAF. No other significant differences for clinical features or surgical procedures were observed. Echocardiographic and CT parameters did not significantly differ between the two groups however older patients who developed POAF had elevated levels of indexed total EATV (96.1±46.6 cm3/m2) (Fig.2). At multivariate logistic regression analysis the only indipendent predictor of POAF remained age (OR: 1.053; 95% CI: 1.018-1.089; p=0.003). CONCLUSIONS: Advanced age is a recognized risk factor for POAF following CS in patients without prior AF history. Older patients who developed POAF had elevated EAT values, however our study did not evidence any link between EAT and POAF. [Figure: see text] [Figure: see text]