Objective
Carotid intima media thickness (CIMT) is reliable marker of subclinical atherosclerosis and cardiovascular events. Until today, there was no study that asked or investigated whether the adipose tissue or circulating lipids is more important for CIMT and atherosclerotic plaque? Therefore, our primary aim is mainly to evaluate the effects of traditional risk factors including circulating lipids and epicardial adipose tissue (EAT) on CIMT and the plaque.
Methods
Our study, having cross-sectional and observational design, included 252 patients who were admitted to our outpatient clinic. EAT identified as an echo-free space under the pericardial layer on 2-dimensional echocardiography, was measured perpendicularly in front of the right ventricular free wall at end-systole. CIMT measurements were performed for the right and left carotid arteries using a high-resolution ultrasonography scanner.
Results
EAT significantly correlated to CIMT (r=0.623, p<0.001), as well as age, BMI, waist circumference, creatinine, uric acid and C-reactive protein. CIMT correlated to age, waist circumference, uric acid, CRP other than EAT. CIMT significantly increased with rising EAT thickness (0.72±0.15, 0.85±0.16, and 0.95±0.12 mm in patients with EAT < 5, 5-7, and >7 mm, p<0.001, respectively). Multiple linear regression analysis revealed that age (Beta: 0.406, p<0.001), male gender (Beta: 0.244, p<0.001) and EAT (Beta: 0.450, p<0.001) as independent correlates of CIMT. Otherwise, in logistic regression analysis, only EAT (OR, 1.386; 95% CI, 1.203-1.597, p<0.001) and LDL (OR, 1.013; 95% CI, 1.002-1.013, p=0.02) were independent predictors for presence of carotid plaque. We determined that there is no increase in CIMT together with increasing LDL concentrations in normal EAT levels (<5mm), unlikely that of increased EAT groups.
Conclusion
Our study showed that EAT has detrimental effects on both CIMT and the development of carotid plaque, but LDL is only independently related to the plaque. This finding suggested that EAT thickness is a risk factor playing an important role beginning from early stages of atherosclerosis. In contrast, LDL cholesterol appears to have a role in later stages of atherosclerosis.
