Impact of abdominal and epicardial fat on the association between plasma adipocytokine levels and coronary atherosclerosis in non-obese patients

Objective: Ectopic fat accumulation is associated with coronary artery disease. Visceral adipose tissue has paracrine and systemic effects and is a source of adipocytokines. It has been implicated in the pathogenesis of coronary atherosclerosis; however, nothing is known about whether increases in epicardial fat have the same effect on coronary atherosclerosis as increases in abdominal visceral fat. Methods: We examined 216 consecutive patients suspected to have coronary artery disease. Individuals with acute coronary syndrome and inadequate computed tomography (CT) imaging were excluded. We enrolled 164 patients (65±10 years old; 70% men; body mass index [BMI], 23.8±3.6kg/m²). The plasma concentrations of adiponectin, interleukin-6 (IL-6), plasminogen activator inhibitor-1, and vascular endothelial growth factor were measured. The characteristics of coronary plaque, abdominal visceral fat area, and epicardial fat volume (EFV) were determined by 64-slice CT imaging. Results: EFV was greater in subjects with noncalcified plaque than in those with no plaque or with calcified plaque (126±39mL vs. 98±34mL and 97±45mL, respectively; P=0.010). EFV was significantly correlated with BMI, triglycerides, and the triglyceride/high-density lipoprotein cholesterol ratio (r=0.51, 0.19, and 0.20, respectively) but not with plasma levels of adipocytokines. The plasma adiponectin and IL-6 concentration was significantly correlated with abdominal visceral fat area in coronary plaque patients (r=-0.49 and 0.20). Conclusions: In non-obese Japanese patients, epicardial fat may have unique mechanisms affecting the development of coronary atherosclerosis, which is different from abdominal visceral fat.