Correlation of coronary and cerebral atherosclerosis: Difference between extracranial and intracranial arteries

Background: A difference with regard to the correlation with coronary atherosclerosis (CAS) between extracranial carotid atherosclerosis (ECAS) and intracranial cerebral atherosclerosis (ICAS) has been assumed but not proven clearly by direct comparison within the same population. Methods: A consecutive series of 246 patients undergoing coronary artery bypass graft surgery were reviewed. The severity of CAS was estimated as a CAS score based on coronary angiography. The presence of ECAS and ICAS was screened by transcranial Doppler and carotid duplex sonography, and confirmed by magnetic resonance angiography. Results: The CAS scores in patients with ECAS were observed to be higher than those in patients without ECAS (10.62 ± 4.80 vs. 9.45 ± 4.25; p = 0.054 on the Mann-Whitney U test). The difference in CAS scores was smaller between patients with and without ICAS (10.41 ± 4.44 vs. 9.66 ± 4.49; p = 0.201). Similar patterns were observed on comparing the correlation of ECAS and ICAS with a quartile of the CAS score. An advanced CAS, which was generated by collapsing the quartiles of the CAS score into 75th percentile or less and more than the 75th percentile, was significantly associated with ECAS, but not with ICAS. These associations remained unchanged after adjustments had been made for age, sex, hypertension, diabetes mellitus, hyperlipidemia, smoking and a history of stroke or transient ischemic attack. Conclusions: This study suggests that the correlation of CAS with ECAS is stronger than that of CAS with ICAS, and this difference is independent of the classic risk factors for atherosclerosis.