Morphometric measurements of extracranial and intracranial atherosclerotic disease: A population-based autopsy study

Abstract

Background and aims: Intracranial (IAD) and extracranial atherosclerotic diseases (EAD) have been mostly investigated using imaging methods. Autopsy studies allow for a direct and complete evaluation of the atherosclerotic disease. We aimed to investigate the frequency of IAD and EAD, their association, and related risk profiles in a large cross-sectional autopsy study.

Methods: We measured the intima-media thickness and stenosis of the common (CCA) and internal carotid arteries (ICA), using morphometric measurements. The main outcome was stenosis (≥50%) in the artery with the largest obstruction among the 12 cerebral arteries. We used multivariable logistic regression models to investigate the association between EAD and IAD.

Results: In 661 participants (mean age = 71.3 ± 11.7 y, 51% male), stenosis was more common in IAD than in EAD (59% vs. 51%). EAD was associated with Caucasian race, hypertension, and smoking, while IAD was associated with older age, less years of education, hypertension, diabetes, and a previous history of stroke. Stenosis in CCA and ICA was associated with more than two times the odds of having stenosis in the intracranial arteries (CCA: OR = 2.32, 95% CI = 1.64; 3.28; ICA: OR = 2.51, 95% CI = 1.76; 3.57).

Conclusions: In this population-based autopsy study, IAD was common, even more common than EAD, but correlated with EAD.

Keywords: Atherosclerosis; Carotid arteries; Cerebral arteries; Epidemiology; Risk factors.

Fig. 1

Artery sections. (A) Section of the basilar artery. The red line represents the area delineated by the outer arterial wall and the blue line indicates the lumen area. (B) a. Sections in the right carotid artery were acquired at (1) the largest arterial obstruction in the common carotid artery, (2) 1 cm below the bifurcation, (3) 1 cm above the bifurcation, and (4) the largest arterial obstruction in the internal carotid artery. b. Section of the right common carotid artery. Red: external elastic lamina; yellow: internal elastic lamina; and blue: lumen. c. Representation of the common carotid artery for the carotid artery intima-media thickness measurement. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)

Fig. 2

Percentage of participants. (A) Percentage of participants with a stenosis index ≥50% in each intracranial artery. B, basilar; LP, left posterior; RP, right posterior; LPC, left posterior communicating; RPC, right posterior communicating; LIC, left internal carotid; RIC, right internal carotid; LM, left middle; RM, right middle; LA, left anterior; RA, right anterior; AC, anterior communicating arteries. (B) Percentage of participants with different numbers of arteries with a stenosis index ≥50%.

Fig. 3

Venn diagram. Venn diagram showing the relationship of a stenosis index ≥50% in any artery of the Circle of Willis (CW) with a stenosis index ≥50% in (A) the common carotid artery (CCA) and (B) the internal carotid artery (CCA). Numbers are absolute frequencies.