Association between Circle of Willis Configuration and Rupture of Cerebral Aneurysms

Abstract

Background and Objectives: Intracranial hemorrhage caused by the rupture of brain aneurysms occurs in almost 10 per 100,000 people whereas the incidence of such aneurysms is significantly higher, accounting for 4–9%.Linking certain factors to cerebral aneurysm rupture could help in explaining the significantly lower incidence of their rupture compared to their presence. The aim of this study is to determine the association between the corresponding circle of Willis configurations and rupture of cerebral aneurysms. Materials and Methods: A group of 114 patients treated operatively for aruptured cerebral aneurysm and a group of 56 autopsied subjects were involved in the study. Four basic types of the circle of Willis configurations were formed—two symmetric types A and C, and two asymmetric types B and D. Results: A statistically significantly higher presence of asymmetry of the circle of Willis was determined in the group of surgically-treated subjects (p = 0.001),witha significant presence of asymmetric Type B in this group (p < 0.001). The changeson the A1 segment in the group of surgically-treated subjects showed a statistically significant presence compared to the group of autopsied subjects (p = 0.001). Analyzing the presence of symmetry of the circle of Willis between the two groups, that is, the total presence of symmetric types A and C, indicated their statistically significant presence in the group of autopsied patients (p < 0.001). Conclusions: Changes such as hypoplasia or aplasia of A1 and the resulting asymmetry of the circle of Willis directly affect the possibility of the rupture of cerebral aneurysms. Detection of the corresponding types of the circle of Willis after diagnostic examination can be the basis for the development of a protocol for monitoring such patients.

A new classification system for the anatomical variations of the human circle of Willis: A systematic review

“…Circle variation has implications for clinical practice. It is associated with an increased risk of ischaemic stroke (Oumer et al, 2021; van Seeters et al, 2015), aneurysm rupture (Lazzaro et al, 2012; Stojanović et al, 2019), white matter disease (Chuang et al, 2011; Ryan et al, 2015) and migraine (Henry et al, 2015). It is also associated with an increased risk of vasospasm post‐subarachnoid haemorrhage (Jacquens et al, 2020).…”

“…F I G U R E 6 Group three of the classification system containing circles with hypoplastic and absent segments only CoW variation is associated with an increase in aneurysm rupture (Lazzaro et al, 2012;Stojanović et al, 2019). It is suggested that future studies investigate the association between variation type, as described in the classification system, and the risk of aneurysm rupture.…”

“…An awareness of the anatomical variations of the CoW is important for clinical practice (Jones et al, 2020; Raikos & Smith, 2015). Circle variation is associated with an increased risk of a number of cerebrovascular diseases (Henry et al, 2015; Oumer et al, 2021; Ryan et al, 2015; Stojanović et al, 2019), and affects patient response to therapeutic intervention (Leng et al, 2016; Wufuer et al, 2017). It has implications for preoperative planning and is important in selecting the most appropriate method of cerebral protection (Papantchev et al, 2013).…”

Variations of the Cerebral Arterial Circle. Morphological and Clinical Analysis

“…The arrangement of this arterial circle is subject of multiple variations, such as aplasia, hypoplasia and duplication of its main components (Okahara et al, 2002;Kapoor et al, 2008;Dimmick & Faulder, 2009). In this sense, variations of this classic pattern are frequent, the presence of hypoplasia and /or aplasia would be linked to the development of ischemic encephalic disorders (Hoksbergen et al, 2003;Karatas et al, 2016;Zhou et al, 2018;Stojanovic et al, 2019;Jones et al). Following this line, the hypoplasia of these vessels are considered as the existence of less than 1 mm external caliber, for both, the A1 and P1 arterial segments and for the ACoA and PCoA (Eftekhar et al, 2006;Karatas et al;El Falougy et al, 2018;Jones et al).…”

Variantes anatómicas del círculo arterial cerebral en un anfiteatro universitario en Bogotá (Colombia)

“…Diversos estudios han mostrado variaciones anatómicas de dicha configuración tanto en material cadavérico como en imágenes diagnósticas, que han descrito la presencia de variantes anatómicas entre un 38 % y un 60 % (5)(6)(7)(8). También se ha descrito la relación de dichas variantes con diversas patologías como aneurismas, rupturas aneurismáticas, infartos cerebrales por procedimientos endovasculares (9)(10)(11) o, incluso, el impacto en la capacidad de compensación en los ataques cerebrovasculares isquémicos (12). Por otra parte, la presencia de variantes anatómicas es importante en la realización de procedimientos como el test de Wada, entre otros procedimientos endovasculares (13,14).…”