Assessment of epicardial adipose tissue and carotid/femoral intima media thickness in insulin resistance

Background: Metabolic syndrome is a combination of multiple cardiovascular (CV) risk factors including insulin resistance (IR). Carotid, femoral intima media thickness (IMT), and epicardial fat thickness (EFT) are considered as novel cardiometabolic risk factors. We aimed to test the hypothesis that carotid, femoral IMT, and EFT are increased in patients with IR.

Methods: We enrolled consecutively and prospectively 113 patients with IR. Then we collected data from an age- and sex-matched control group of 112 individuals without IR. Homeostasis model assessment (HOMA) index value >2.5 was accepted as IR. Patients with diabetes mellitus, CV diseases, systolic heart failure, chronic liver or renal diseases were excluded. On B-mode duplex ultrasound the mean IMT at the far wall of both left and right common carotid/femoral arteries were measured manually. EFT was measured on the free wall of the right ventricle at end-diastole from the parasternal long-axis views by standard transthoracic 2D echocardiography.

Results: Both carotid IMT and EFT were significantly higher in patients with IR compared to controls (0.80±0.21mm vs 0.60±0.21mm; p<0.001 and 7.34±1.96mm vs 5.22±1.75mm; p<0.001, respectively). However, there were no significant differences in femoral IMT between the groups (0.74±0.20 vs 0.69±0.17; p=0.062). In multivariate linear regression analysis age (β=0.223, p=0.010), 2-h blood glucose (β=0.198, p=0.021), and IR (β=0.369, p<0.001) were independent predictors of EFT. On the other hand age (β=0.363, p<0.001) and IR (β=0.321, p<0.001) were independent predictors of carotid IMT.

Conclusions: Patients with IR have increased carotid IMT and EFT, but not femoral IMT. This apparent incoherence may be due to the involvement of carotid arteries prior to femoral arteries in patients with IR.