Thickness of epicardial adipose tissue reflects the metabolic and cardiovascular status of patients in T1DM population

Introduction Epicardial adipose tissue (EAT) is defined as the fatty layer located between the visceral pericardium (epicardium) and the myocardial surface. EAT is not simply a passive fat depot but an active endocrine organ linking metabolic disturbances to cardiovascular complications. According to the literature, its thickness correlates with the presence of diabetes and, in HFpEF population, with the exercise capacity-, and the characteristic echocardiographic parameters of the patients. However, there is little data available on the relationship between EAT thickness and the metabolic or cardiovascular status of the patients in type 1 diabetes mellitus (T1DM) population. Purpose Our aim was to investigate the correlations between laboratory, exercise test-derived, and echocardiographic parameters of the patients and thickness of EAT in asymptomatic T1DM population. Methods Seventy T1DM-patients (38±12 years, 46 female, HbA1c: 7.6±1.3%, BMI: 24.8±4.2 kg/m²) were enrolled. Hypertension did not, but other known cardiovascular diseases served as exclusion criteria. Their results were compared with those of 30 volunteers matched for age, gender and BMI. Maximal thickness of EAT was measured with 2D echocardiography, on mid-papillary level parasternal short-axis images, at the right ventricular free wall, in end-systole. Values obtained in three different cardiac cycles were averaged. Results EAT was significantly thicker in T1DM patients than in volunteers (3.81±0.11 vs. 2.23±0.05 mm, p<0.001). Within the T1DM population, EAT was thicker in hypertensive patients (n=22) than in others (4.31±0.20 vs. 3.58±0.11 mm, p=0.001). In T1DM patients, EAT thickness showed significant correlation with the following parameters: one-year mean HbA1c (r=0.263, p=0.028); exercise test-derived metabolic equivalent (MET) (r=-0.314, p=0.011); LVM index (r=0.350, p=0.003), mitral average e’ (r=-0.335, p=0.005) and E/e’ (r=0.272, p=0.023); tricuspid e’ (r=-0.338, p=0.004), e’/a’(r=-0.344, p=0.004) and E/e’ (r=0.297, p=0.012); left atrial reservoir (r=-0.320, p=0.007) and conduit (r=-0.444, p<0.001) strain; right atrial reservoir (r=-0.293, p=0.014) and conduit (r=-0.361, p=0.002) strain. Conclusion Thickness of EAT was significantly higher in T1DM patients than in healthy persons, despite similar BMI. Within T1DM population, EAT thickness showed significant correlation with the quality of the glycaemic control, with the presence of hypertension, with exercise capacity of the patients and with various echocardiographic parameters of the diastolic function in both the left and right heart.