Pericardial Rather Than Epicardial Fat is a Cardiometabolic Risk Marker: An MRI vs Echo Study

Abstract

Several studies using echocardiography identified epicardial adipose tissue (EPI) as an important cardiometabolic risk marker. However, validation compared with magnetic resonance imaging (MRI) or computed tomography has not been performed. Moreover, pericardial adipose tissue (PERI) has recently been shown to have some correlation with cardiovascular disease risk factors. The aims of this study were to validate echocardiographic analyses compared with MRI and to evaluate which cardiac fat depot (EPI or PERI) is the most appropriate cardiovascular risk marker. Forty-nine healthy subjects were studied (age range, 25-68 years; body mass index, 21-40 kg/m(2)), and PERI and EPI fat depots were measured using echocardiography and MRI. Findings were correlated with MRI visceral fat and subcutaneous fat, blood pressure, insulin sensitivity, triglycerides, cholesterol, insulin, glucose, and 10-year coronary heart disease risk. Most cardiac fat was constituted by PERI (about 77%). PERI thickness by echocardiography was well correlated with MRI area (r= 0.36, P= .009), and independently of the technique used for quantification, PERI was correlated with body mass index, waist circumference, visceral fat, subcutaneous fat, blood pressure, insulin sensitivity, triglycerides, cholesterol, glucose, and coronary heart disease risk. On the contrary, EPI thicknesses correlated only with age did not correlate significantly with MRI EPI areas, which were found to correlate with age, body mass index, subcutaneous fat, and hip and waist circumferences. Increased cardiac fat in the pericardial area is strongly associated with features of the metabolic syndrome, whereas no correlation was found with EPI, indicating that in clinical practice, PERI is a better cardiometabolic risk marker than EPI.