Original Article
Race-ethnic Variation in Carotid Bifurcation Geometry

https://doi.org/10.1016/j.jstrokecerebrovasdis.2009.01.002Get rights and content

Background

Disturbances in local blood flow influenced by arterial geometry contribute to atherogenesis. Carotid bifurcation hemodynamics depend on the relative sizes of the common carotid artery (CCA), internal carotid artery (ICA), and external carotid artery (ECA), which vary considerably among individuals. The prevalence of carotid bifurcation atherosclerosis differs among race-ethnic groups and is generally lower in African Americans despite a more adverse vascular risk factor profile. We here examine whether there are race-ethnic differences in carotid bifurcation anatomy.

Methods

The diameters of the CCA, carotid bulb, ICA, and ECA were measured from consecutive cerebral angiograms of African American, white, and Caribbean Hispanic patients. The bulb/CCA, ICA/CCA, ECA/CCA, ECA/ICA, and total cross-sectional outflow/inflow ratio ([ICA2 + ECA2]/CCA2) were calculated.

Results

The final analysis included 272 bifurcations of which 103 were among white, 87 Hispanic, and 82 African American patients. The mean age of the population was 59.8 ± 15.8 years and 148 (54.4%) were men. African Americans had a lower ICA/CCA ratio (P < .001) and ICA/ECA ratio (P < .0001) and a higher ECA/CCA ratio (P < .0001) in comparison with the other two groups.

Conclusion

We found significant differences in the relative sizes of the ICA, ECA, and CCA among race-ethnic groups. African Americans had a proportionally smaller ICA and larger ECA in comparison with whites and Caribbean Hispanics.

Section snippets

Methods

We reviewed carotid bifurcation anatomy from all consecutive catheter cerebral angiograms requested by the neurologic service of a large community-based teaching hospital obtained during a 3-year period. Biplanar digital subtraction angiography was performed in all cases and printed images were reviewed. All cerebral angiograms were done by two angiographers using the same equipment thereby minimizing any differences in technique, image magnification, or projection angle.

The vascular anatomy

Results

A total of 153 cerebral angiograms were examined among 60 white, 48 Caribbean Hispanic, and 45 African American patients. The final analysis included 272 bifurcations of which 103 were among white, 87 Hispanic, and 82 African American patients.

The mean age of the population was 59.8 ± 15.8 years and 148 (54.4%) were men. Differences in clinical characteristics and vascular risk factors among racial groups are shown in Table 1. African Americans were younger than the other two groups and had a

Discussion

We found significant race-ethnic differences in the anatomy of the carotid bifurcation. African Americans have a proportionally smaller ICA and larger ECA than whites and Caribbean Hispanics.

It is generally thought that whites have an increased prevalence of extracranial atherosclerotic cerebrovascular disease than other race-ethnic groups. Several studies have reported a reduced prevalence of extracranial atheroma in blacks.10, 11, 12, 17 Such differences were originally reported by early

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