Circle of Willis Variation: Implications for Aneurysm, Atherosclerosis, and Stroke

Abstract

Arterial variations within the Circle of Willis, especially hypoplastic arteries, are linked to intracranial aneurysm, atherosclerosis, and stroke; therefore, the study of Circle of Willis variants are of clinical importance. In a sample of 116 cadavers, the arteries comprising the Circle of Willis were directly observed and assessed for hypoplasia, hyperplasia, aplasia, duplication, triplication, and plexiform structure. A total of 53 different arterial patterns of the Circle of Willis were identified. The most common vascular pattern was one with no noteworthy variation of the arteries, which occurred in 34.48% (40:116) of the sample. The second most common pattern was a right hyperplastic posterior communicating artery, with concomitant right hypoplastic P1 and right hyperplastic P2 vessels which occurred in 3.45% (4:116) of cadavers. The most common variation of an individual artery, regardless of concomitant variations, was a hyperplastic right posterior communicating artery, which occurred in 19.8% (23:116) of the sample. Similarly, a right hyperplastic P2, right hyperplastic posterior communicating artery, left hypoplastic P1, and left hyperplastic posterior communicating artery each occurred in 18.1% (21:116) of cadavers. A duplicated anterior communicating artery was observed in 12.9% (15:116) of cadavers. Aplasia was only observed in the posterior communicating artery (left‐sided: 7.8%; 9:116, right‐sided: 6.0%; 7:116). The results of this study provide a clearer understanding of the variant vascular patterns of the Circle of Willis that create predisposition for aneurysm, atherosclerosis, and stroke.Support or Funding InformationWest Virginia University, Oman Medical College and West Liberty UniversityThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.