Relationship between intima-media thickness in the common carotid artery and atherosclerosis in the carotid bifurcation

Background and Purpose-An increase in intima-media thickness (IMT) in the common carotid artery (CCA) is commonly used as a marker of atherosclerosis. The purpose of this study was to investigate the relationship between IMT in the CCA and atherosclerosis in the carotid bifurcation. Methods-182 consecutive patients (mean age, 67 years) referred for carotid duplex scanning were included. We measured IMT and classified plaques by means of a high-resolution ultrasound technique. Results-IMT was correlated to age, male gender, ischemic heart disease, and presence of plaques or stenoses in any of the carotid bifurcations. In men, IMT was larger on the left than on the right side. Plaques were seen in 163 carotid bifurcations, in 45 of these with >50% stenosis. On the left side but not on the right, there was a correlation between IMT in the CCA and presence of plaques or stenoses in the carotid bifurcation. Echogenic plaques were more common than echolucent, but the latter caused significantly more stenoses. No relationship was found between plaque echogenicity and IMT. Conclusions-IMT of the CCA is correlated to the degree of atherosclerosis in the carotid bifurcations in general and on the left side also to the presence of plaques or stenoses in the left carotid bifurcation. Our results support earlier observations suggesting faster development of carotid atherosclerosis on the left than on the right side. Echogenic plaques were more common and generally smaller than echolucent plaques, but there was no correlation between plaque echogenicity and IMT.