Lack of Anterior Communicating Artery Is Associated with Symptomatic Middle Cerebral Artery Atherosclerosis

Background: Dysplasia or absence of anterior communicating artery (ACoA) is a common variation in the circle of Willis (COW) anomaly, and it may elevate the risks of cerebrovascular diseases. We aimed at investigating the association of ACoA dysplasia/absence with plaque imaging features of middle cerebral artery (MCA) atherosclerosis. Methods: We analyzed the prospective data from a vessel wall imaging cohort of adult patients suffering from acute ischemic stroke or transient ischemic attack due to intracranial atherosclerosis (2014 to 2020). Patients demonstrating MCA atherosclerotic plaques were included. The ACoA dysplasia/absence and other incomplete COW configurations were identified on magnetic resonance angiography. The MCA plaques were evaluated through high-resolution vessel wall imaging. Results: Of the 107 patients with MCA atherosclerosis, 29.9% showed ACoA dysplasia/absence. The patients with ACoA dysplasia/absence were more likely to have concomitant dysplasia/absence of anterior cerebral artery (71.9% vs. 18.7%, p < 0.001). For the 158 MCA plaques identified, those with ACoA dysplasia/absence exhibited a significantly higher prevalence of symptomatic status (58.7% vs. 31.3%, p = 0.001) and non-positive remodeling (58.7% vs. 26.8%, p < 0.001) than those without this variant. Regression analyses further demonstrated the robust association of ACoA dysplasia/absence with symptomatic status (odds ratio, 5.158; 95% confidence interval, 1.744-15.254; p = 0.003) and non-positive remodeling (odds ratio, 6.92; 95% confidence interval, 2.396-19.982; p < 0.001) of MCA atherosclerosis. Conclusions: As a common variation among patients with MCA atherosclerosis, ACoA dysplasia/absence may elevate the possibility to develop symptomatic MCA atherosclerosis, which showed non-positive remodeling. Stroke risk stratification based on the ACoA morphology needs further validation.