Abstract 9416: The Impact of Epicardial Fat Volume on Coronary Artery Disease in Symptomatic Patients of Zero Calcium Sore

Abstract

Background Patients without detectable coronary calcium by computed tomography (CT) have a low rate of obstructive coronary disease and good prognosis. However, in some patients with zero coronary calcium score (zero CS), obstructive coronary stenosis exists and fatal cardiovascular events occur, especially among symptomatic patients. Epicardial fat is known to be a rich source of free fatty acid and inflammatory cytokines and epicardial fat volume (EFV) has been suggested as a predictor of coronary artery disease. The aim of our study is to investigate the impact of EFV on coronary artery disease in symptomatic patients with zero CS. Methods and Results From June 2009 to April 2011, consecutive 483 symptomatic patients who underwent multislice CT (MSCT) with zero CS were evaluated. EFV was calculated using dedicated software with manual assistance in defining the epicardial contour on CT images. In each patient, obstructive coronary disease (diameter stenosis>50% on MSCT) and CT-derived vulnerable plaque were assessed with 64-slice CT coronary angiography. CT-derived vulnerable plaque was defined as a plaque with positive vessel remodeling (lesion vessel area>proximal reference vessel area) and low CT attenuation (mean CT density value of the plaque<30Hounsfield Units). In patients with obstructive coronary disease (n=25), EFV was larger (117.8±40.9cm 3 vs 95.9±41.1cm 3 , p<0.01) and diabetes mellitus (DM) was more common(24% vs 6%, p<0.01) than without obstructive coronary disease. In multivariate analysis, EFV (per 10cm 3 ) remained the independent predictor for obstructive coronary disease (Odds ratio(OR);1.20, 95% confidence interval (CI)1.09-1.31, p<0.01). The patients with CT-derived vulnerable plaque (n=20) had larger EFV than without CT-derived vulnerable plaque (136.4±34.2cm 3 vs 95.4±40.8cm 3 , p<0.01). CT-derived vulnerable plaques were more frequently observed in males (70 % vs 44%, p=0.03) and DM patients (25 % vs 6%, p< 0.01). After adjustment for DM and gender, EFV (per 10cm 3 ) remained the independent predictor of the presence of CT-derived vulnerable plaque (OR; 1.20, 95%CI; 1.09-1.32, p<0.01). Conclusions EFV can be a useful marker of coronary artery disease in symptomatic patients with zero CS.