Common carotid artery intima-media thickness determinants in a population study

Objective. Common carotid artery (CCA) intima-media thickness (IMT) is considered an atherosclerosis risk marker. Thickening of the intima-media complex is accelerated by vascular risk factors, in particular, by age and elevated blood pressure. Nonetheless, it also reflects intimal hyperplasia and intimal fibrocellular hypertrophy provoked by nonatherosclerotic mechanisms such as tensile wall stress. The aims of our study were to investigate the relationship between CCA IMT and the presence of vascular risk factors and to correlate CCA IMT with the degree of distal internal carotid artery (ICA) stenosis and the proximal CCA resistive index (RI), representative of wall stress. Methods. We assessed CCA IMT, the CCA RI, and the presence of carotid plaques in 1655 consecutive patients. Demographic features and vascular risk factors were collected. Results. A positive linear relationship between mean IMT and age was observed (R-2 = 0.27; P < .001). In the multiple stepwise regression model, the presence of ICA plaques and vascular risk factors were all independently associated with higher IMT. When considering IMT values for left and right sides separately, there was an independent relationship between CCA IMT and the lateralized percentage of ICA stenosis (right IMT-right ICA percentage, R-2 = 0.10; P < .0001; left IMT-left ICA percentage, R-2 = 0.16; P < .0001) and the CCA RI, even after correcting for age and vascular risk factors. Conclusions. Risk factors for atherosclerosis and the percentage of ICA stenosis were independently associated with higher IMT values and an increase in the RI. The synergic action of risk factors may cause further deterioration of mechanical forces independent of carotid atherosclerosis.