Association Between Incomplete Circle of Willis and Carotid Vulnerable Atherosclerotic Plaques

Area of Science:

• Neuroimaging and Cerebrovascular Disease
• Cardiovascular Research
• Radiology and Medical Imaging

Background:

• High-risk carotid plaques, marked by intraplaque hemorrhage, fibrous cap rupture, and large lipid-rich necrotic cores, are linked to cerebrovascular events.
• The circle of Willis (COW) is crucial for collateral circulation to the brain, and its incomplete formation may influence cerebrovascular event risk.

Purpose of the Study:

• To investigate the relationship between high-risk carotid plaque features and an incomplete circle of Willis (COW).
• To determine if an incomplete COW is independently associated with specific carotid plaque characteristics, particularly intraplaque hemorrhage.

Main Methods:

• Utilized 3D time-of-flight magnetic resonance angiography for intracranial arteries and 2D multicontrast magnetic resonance vessel wall imaging for carotid arteries in 482 patients from the CARE-II study.
• Evaluated the integrity of the anterior and posterior portions of the COW and assessed carotid plaque characteristics, including intraplaque hemorrhage.

Main Results:

• Patients with carotid intraplaque hemorrhage had a significantly higher prevalence of an incomplete anterior COW (52.7%) compared to those without (38.5%; P=0.022).
• An incomplete anterior COW was independently associated with intraplaque hemorrhage, even after adjusting for clinical risk factors (OR, 1.945; P=0.015).
• No significant correlation was found between unilateral carotid artery stenosis or other plaque features and incomplete COW.

Conclusions:

• An incomplete circle of Willis (COW) is independently associated with the presence of intraplaque hemorrhage in carotid atherosclerotic plaques.
• This association suggests a potential link between cerebral collateral circulation anatomy and the development of high-risk carotid plaques.