CORRELAÇÃO ENTRE AS VARIAÇÕES ANATÔMICAS NO CÍRCULO ARTERIAL DE WILLIS E O ACIDENTE VASCULAR ENCEFÁLICO

• DOI: https://doi.org/10.22533/at.ed.4882405026

• Palavras-chave: "Polígono de Willis", "Variações Anatômicas", "Acidente Vascular Encefálico"

• Keywords: “Circle of Willis”, “Anatomical variations”, “Cerebrovascular accident”

• Abstract: Objectives: Review the anatomy of the Circle of Willis (CoW), emphasizing its main anatomical variations and linking them to potential physiopathological changes capable of increasing the incidence of stroke in the general population. Methods: An anatomical, physiopathological, and epidemiological literature review was conducted using Pubmed, Scielo, and Google Scholar databases. Employing the descriptors  "Circle of Willis," "Anatomical variations," and "stroke." The classic anatomy of the CoW was addressed, also covering the main variations in the vascularization of the skull base and related epidemiological and physiopathological aspects, with a focus on the potential increase in stroke risks. Results: Given the potential role of the CoW in maintaining adequate blood flow in the face of processes compromising cerebral irrigation, the association between some local anatomical variants and the development of efficient collateral circulation showed a reduction in the risks of transient ischemic attack and strokes compared to patients without the development of these collateral arteries. Additionally, most case studies describe hypoplasia of the posterior communicating artery (PcoA) as the main variation found in the CoW, with its smaller diameter associated with an increased likelihood of ischemic events. The reported prevalence range of PcoA hypoplasia was 8% to 28.7%. Furthermore, there is an association between the persistence of fetal arterial segments related to poor development of compensatory collateral circulation in occlusive conditions, favoring the outcome of strokes. Conclusions: There is evidence that variations in the classic morphology of the CoW can lead to diverse circulatory repercussions, particularly in cases of arterial hypoplasia and persistence of fetal vessels in adults. These variations are associated with the poor development of compensatory collateral circulation in occlusive conditions, leading to extensive deficits in ischemic scenarios. Thus, detailed anatomical knowledge correlated with an understanding of cerebral hemodynamics could assist in elucidating ongoing questions in the scientific community regarding various clinical syndromes, offering the possibility of safer endovascular interventions and open neurosurgical procedures. Consequently, it enables the provision of a more favorable prognosis for patients at increased risk of strokes.