Measurement of epicardial fat thickness by transthoracic echocardiography for predicting high-risk coronary artery plaques.

Abstract

Epicardial adipose tissue (EAT) volume is reported to be associated with coronary plaques. We evaluated whether non-invasive measurement of EAT thickness by echocardiography can predict high-risk coronary plaque characteristics determined independently by coronary computed tomography (CT) angiography. We enrolled 406 patients (mean age 63years, 57% male) referred for 64-slice CT. EAT was measured on the right ventricle free wall from a parasternal long-axis view at the end of systole. High-risk coronary plaques were defined as low-density plaques (<30Hounsfield units) with positive remodeling (remodeling index >1.05). Patients were divided into thin or thick EAT groups using a cutoff value derived from receiver operator characteristic curve analysis for discriminating high-risk plaques. The receiver operator characteristic cutoff value was 5.8mm with a sensitivity of 83% and specificity of 64% (area under the curve 0.77, 95% confidence interval 0.70-0.83, p<0.01). Compared with the thin EAT group, the thick EAT group had a high prevalence of low-density plaques (4 vs. 24%, p<0.01), positive remodeling (39 vs. 60%, p<0.01), and high-risk plaques (3 vs. 17%, p<0.01). Multiple logistic analysis revealed that thick EAT was a significant predictor of high-risk plaques (odds ratio 7.98, 95% confidence interval 2.77-22.98, p<0.01) after adjustment for covariates, including conventional risk factors, visceral adipose tissue area, and medications. The measurement of EAT thickness by echocardiography may provide a non-invasive option for predicting high-risk coronary plaques.