Epicardial Adipose Tissue Thickness and Its Association With the Presence and Severity of Coronary Artery Disease in Clinical Setting: A Cross-Sectional Observational Study

BACKGROUND: Obesity is an important risk factor for atherosclerotic cardiovascular disease (ASCVD). Estimation of visceral adipose tissue is important and several methods are available as its surrogate. Although correlation of epicardial adipose tissue (EAT) with visceral adipose tissue as estimated by magnetic resonance imaging (MRI) and/or CT is excellent, it is costlier and cumbersome. EAT can be accurately measured by two-dimensional (2D) echocardiography. It tends to be higher in patients with acute coronary syndrome than in subjects without coronary artery disease (CAD) and in those with stable angina. It also carries advantage as index of high cardiometabolic risk as it is a direct measure of visceral fat rather than anthropometric measurements. The present study evaluated the relationship of EAT to the presence and severity of CAD in clinical setting. METHODS: In this prospective, single-center study conducted in the Department of Cardiology, LPS Institute of Cardiology, Kanpur, India, 549 consecutive patients with acute coronary syndrome or chronic stable angina were enrolled. Sensitivity, specificity, and receiver operating characteristic (ROC) curve were estimated to find cut-off value of EAT thickness for diagnosing CAD using coronary angiographic findings as gold standard. RESULTS: Patients were diagnosed as CAD group (n = 464, 60.30 ± 8.36 years) and non-CAD group (n = 85, 54.42 ± 11.93 years) after assessing coronary angiograms. The EAT was measured at end-systole from the PLAX views of three cardiac cycles on the free wall of the right ventricle. Lesion was significant if > 50% in left main and > 70% in other coronary arteries. The mean EAT thickness in CAD group was 5.10 ± 1.06 and in non-CAD group was 4.36 ± 1.01 which was significant (P = 0.003). Significant correlation was demonstrated between EAT thickness and presence of CAD (P < 0.003). Higher EAT was associated with severe CAD and presence of multivessel disease. By ROC analysis, EAT > 4.65 mm predicated the presence of significant coronary stenosis by 71.6% sensitivity and 73.1% specificity. CONCLUSION: EAT thickness measured using transthoracic echocardiography (TTE) significantly correlates with the presence and severity of CAD. It is sensitive, easily available, and cost-effective and assists in the risk stratification and may be an additional marker on classical risk factors for CAD.