Relation between cardiovascular disease risk factors and epicardial adipose tissue density on cardiac computed tomography in patients at high risk of cardiovascular events.

Background The radiodensity of epicardial adipose tissue may provide information on cardiovascular risk in addition to epicardial adipose tissue volume. The aim of this study was to quantify the relation between cardiovascular risk factors and the radiodensity of epicardial adipose tissue in patients at high risk of cardiovascular disease. Design This was a cross-sectional study in 140 patients at high risk of cardiovascular disease. Methods Patients from the Secondary Manifestations of ARTerial disease (SMART) cohort study were invited to undergo cardiac computed tomography angiography. The radiodensity (in Hounsfield units; HU) and volume (in cm3) of epicardial adipose tissue were quantified semi-automatically. Multivariable linear regression was used to quantify the relation between cardiovascular risk factors and the radiodensity of epicardial adipose tissue. Results The cardiovascular risk factors most strongly associated with epicardial adipose tissue density were sex, body mass index and visceral fat, with a lower adipose tissue attenuation of 3.5 HU (95% confidence interval (CI) 2.0-5.0 HU) for female sex, 1.6 HU (95%CI 0.2-2.9 HU) for body mass index >25 kg/m2 and 1.3 HU (95% CI 0.6-2.0 HU) for a one standard deviation higher quantity of visceral fat, adjusted for age, sex, coronary artery bypass graft history and epicardial adipose tissue volume. Conclusion Low epicardial adipose tissue computed tomography attenuation is associated with an adverse cardiovascular risk factor profile in patients at high risk of cardiovascular disease, independent of the volume of epicardial adipose tissue and waist circumference. These findings support the potential role for epicardial adipose tissue radiodensity as a valid biomarker of cardiovascular risk. Adipose tissue radiodensity may be a more sensitive marker than epicardial adipose tissue volume with which to study the contribution of epicardial adipose tissue to the coronary atheromatous disease process.