Absent Collateral Function of the Circle of Willis as Risk Factor for Ischemic Stroke

Abstract

Background: Autopsy studies show a higher prevalence of circle of Willis anomalies in brains with signs of ischemic infarction. Our goal was to examine the collateral function of the circle of Willis in ischemic stroke patients and to assess in a case-control study if a collateral deficient circle of Willis is a risk factor for ischemic stroke in patients with severe internal carotid artery (ICA) occlusive disease. Methods: Our case-control study included 109 patients with an acute ischemic stroke in the anterior circulation and 113 patients with peripheral arterial disease and no known history of cerebral ischemia. The collateral function of the anterior and posterior communicating arteries of the circle of Willis was assessed by means of transcranial color-coded duplex ultrasonography (TCCD) and carotid compression tests. Results: TCCD was successfully performed in 75 case patients (mean age 64 years, range 41–91 years) and in 100 control patients (mean age 61 years, range 35–89 years). In 26 cases and 19 controls, a ≧70% stenosis or occlusion of the ICA was found. A nonfunctional anterior collateral pathway in the circle of Willis was found in 33% of the cases and in 6% of the controls (p < 0.001). The posterior collateral pathway was nonfunctional in 57% of the cases and in 43% of the controls (p = 0.02). In patients with severe ICA occlusive disease, the odds ratios of a nonfunctional anterior and a nonfunctional posterior collateral pathway were 7.33 (95% confidence interval, CI, = 1.19–76.52) and 3.00 (95% CI = 0.77–12.04), respectively. Conclusions: Patients who suffer ischemic stroke in the anterior circulation have a higher incidence of collateral deficient circles of Willis than those with atherosclerotic vascular disease without ischemic cerebrovascular disease. The presence of a nonfunctional anterior collateral pathway in the circle of Willis in patients with severe ICA occlusive disease is strongly associated with ischemic stroke.

Configurations of the circle of Willis: a computed tomography angiography based study on a Polish population

“…This is due to the fact that each particular evaluation technique has different characteristics and limitations [5,6,9]. Furthermore, it should be noted that a number of previously published studies were carried out on patients with cerebrovascular disorders [3,6,8,11].…”

“…These incidents may result from disorders such as occlusive disease [8,14] or from surgical procedures, for instance aortic dissection (intraoperative ischaemia) [15]. Additionally, the role of the CW in migraine [3] and aneurysm development [2] has been widely studied.…”

Intraoperative 16-Channel Electroencephalography and Bilateral Near Infrared Spectroscopy Monitorization in Aortic Surgery

“…İnkomplet willis poligonu prevalansı bazı serilerde %50'ye kadar varan oranlarda tespit edilmiştir ve bu durum serebral perfüzyon bozukluğunun %15'inden sorumlu tutulmaktadır (13,14). Girişim sırasında kontralateral hemisferin desatürasyonu NIRS ve EEG monitörleri ile hızlıca tespit edilerek sol karotid arter ayrıca kanüle edilip ek olarak sol beyin perfüzyonu sağlana-bilir.…”

Circle of Willis anomalies in stroke patients related with symptomatic carotid artery disease

“…Araştırıcılar şiddetli karotis darlığının WP' da belirgin hemodinamik artışa yol açmadığını fakat karotisde oklüzyon olduğunda anteriyor kommunikan arterde belirgin çap artışı ortaya çıktığını bildirmişlerdir. TCD ile yapılan bir çalışmada WP'u anteriyor segmentlerinde bir anomali olduğunda karotis arter hastalığına bağlı inme riskinin arttığı saptanmıştır (15). BT anjiyografi ile yakın zamanda yapılan bir diğer çalışmada, WP anomalisi ile semptomatik karotis darlığı arasında bir ilişki olduğu gösterilmiştir (1).…”