Epicardial fat and its association with cardiovascular risk: A cross-sectional observational study

Abstract

Background:The association between visceral obesity and cardiovascular risk has been well described. Some studies show a proportional relationship between the presence of visceral obesity and epicardial fat. Measuring the amount of epicardial adipose tissue (EAT) can be a novel parameter that is inexpensive and easy to obtain and may be helpful in cardiovascular risk stratification. However, the relationship between epicardial fat and cardiac function and that between epicardial fat and cardiac risk factors is less well described.Objectives:To evaluate the association between echocardiographic epicardial fat and the morphologic and physiologic changes observed at echocardiography and to evaluate the association between epicardial fat and cardiac risk factors. A cross-sectional study of 97 echocardiographic studies (females, n = 42) was conducted. Two groups were identified: epicardial fat ≥ 5 mm (group I) and <5 mm (group II).Results:Epicardial fat >5 mm was associated with LA enlargement, with lower ejection fraction, increased left ventricular mass, and abnormal diastolic function. On a multivariable regression analysis, all these parameters also correlated individually with EAT thickness independent of age. Hyperglycemia (DM), systolic hypertension, and lipid parameters for metabolic syndrome showed a trend for positive association, but this was not statistically significant. The association was not significant even for higher cutoff limits of EAT thickness.Conclusion:Epicardial fat >5 mm is associated with cardiac abnormalities on echocardiography. This is a sensitive assessment of body fat distribution, is easily available at echocardiography, and is simple to acquire at no added cost. Further studies looking at the appropriate cut-off thickness of EAT and the sites of measurement to be used are needed. Comparison of this simple and inexpensive measure with other measures of obesity, such as waist-hip ratio, body mass index, Dexa scan of visceral fat, and magnetic resonance imaging of visceral, are needed.

Impact of obesity and epicardial fat on early left atrial dysfunction assessed by cardiac MRI strain analysis

“…These include increased ventricular stiffness, inflammation mediated by adipokines, direct lipotoxicity or a metabolic effect mediated by insulin resistance [9]. Diastolic dysfunction has been previously shown to correlate with duration of diabetes, HbA1c and obesity [24].…”

“…Recent data shows that diabetes is an independent risk factor predictive of LA enlargement and dysfunction. Data has also linked epicardial fat to LA and ventricular functional changes [9], and to increased LA volume [10, 11]. A highly powered analysis using a Framingham cohort demonstrated that this association is independent of other measures of adiposity in men [11].…”

Association of Epicardial Fat, Hypertension, Subclinical Coronary Artery Disease, and Metabolic Syndrome With Left Ventricular Diastolic Dysfunction

“…Epicardial fat correlates with BMI and is increased in obese subjects 3 . The association of increased EFV with diastolic dysfunction may be confounded by factors such as metabolic syndrome 4,24 and hypertension 25 which are often present in obese individuals. Furthermore, increased epicardial fat appears to be related to increased atherosclerotic plaque burden, concomitant coronary artery disease, myocardial ischemia and subclinical microvascular dysfunction which is commonly seen in diabetics and in individuals with metabolic syndrome 3,5,20 .…”

“…Several thresholds have been proposed to indicate increased cardiovascular risk 4 . However, the reproducibility of this method is imperfect, probably because these measurements only represent one planar dimension which is subject to the probe angulation, adequate visualization of the cardiac structure and the given phase of the cardiac cycle chosen to be measured.…”

“…Epidemiological studies have shown that epicardial fat, a metabolically active fat depot, is strongly associated with obesity, metabolic syndrome and diabetes. 3,4 The proximity of epicardial fat to the coronary arteries has been used to explain the association of epicardial fat volume (EFV) with increased coronary artery calcium, atherosclerotic plaque, and myocardial ischemia. 3,5–7 Although these factors may be responsible for diastolic dysfunction, epicardial fat may also have a direct paracrine effect on the myocardium and thereby alter the structural properties of the left ventricle.…”