Background Circle of Willis is the main structure that provides constant and regular blood flow to the brain, protects the brain from ischemia. Stroke has remained the second leading cause of death globally in the last fifteen years. It is the fifth leading cause of death in the United States. It is also the leading cause of serious adult disability. Interlinked problems related to ischemic stroke are become increasing nowadays. Strong evidence is needed about the pooled measure of association between the circle of Willis (COW) and ischemic stroke. Therefore, this systematic review and meta-analysis were intended to provide compressive and up to date evidence on the association between the variations of COW and ischemic stroke using the available studies. Methods PubMed, Google Scholar, Science Direct, and Cochrane Library databases were systematically searched. All essential data were extracted using a standardized data extraction template. The heterogeneity across studies was assessed by using the Cochrane Q test statistic, I 2 test statistic, and P-values. A fixed-effect model was used to estimate the pooled effect of the measure association between COW and ischemic stroke. Results In this meta-analysis, 2,718 participants were involved. The pooled measure of association between COW and ischemic stroke was 1.38 (95% CI 0.87, 2.19). Therefore, this indicated that the presence of any variation in COW was 1.38 times more likely to develop ischemic stroke as compared to the patent COW. The presence of hypoplasia/incompleteness in a posterior communicating artery (PcomA) [Pooled OR: 1.34 (95% CI 0.80, 2.25)] and anterior communicating artery (AcomA) [Pooled OR: 1.32 (95% CI 0.81, 2.19)] were a contributing factor for the development of ischemic stroke. Hypertension was the most common comorbid condition, followed by diabetes mellitus, smoking, coronary artery disease, and hyperlipidemia. Conclusions There was a non-significant positive association between COW variation and ischemic stroke in this meta-analysis.

中文翻译：

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威利斯环与缺血性卒中的相关性：系统评价和荟萃分析

背景 Willis 环是为大脑提供恒定和有规律的血流，保护大脑免受缺血的主要结构。在过去的十五年中，中风一直是全球第二大死因。它是美国第五大死因。它也是导致严重成人残疾的主要原因。如今，与缺血性中风相关的相互关联的问题越来越多。关于威利斯环 (COW) 和缺血性卒中之间关联的汇总测量需要强有力的证据。因此，本系统评价和荟萃分析旨在利用现有研究提供有关 COW 变异与缺血性卒中之间关联的最新证据。方法 PubMed、Google Scholar、Science Direct、和 Cochrane 图书馆数据库进行了系统搜索。使用标准化的数据提取模板提取所有基本数据。通过使用 Cochrane Q 检验统计量、I 2 检验统计量和 P 值评估研究间的异质性。使用固定效应模型来估计 COW 与缺血性卒中之间测量关联的综合效应。结果 在这项荟萃分析中，涉及 2,718 名参与者。COW 与缺血性卒中之间关联的汇总测量值为 1.38 (95% CI 0.87, 2.19)。因此，这表明与专利 COW 相比，存在任何 COW 变异的可能性是发生缺血性中风的 1.38 倍。后交通动脉 (PcomA) 发育不全/不完整 [合并 OR：1.34 (95% CI 0.80, 2. 25)] 和前交通动脉 (AcomA) [合并 OR：1.32 (95% CI 0.81, 2.19)] 是缺血性卒中发生的一个促成因素。高血压是最常见的合并症，其次是糖尿病、吸烟、冠状动脉疾病和高脂血症。结论 在该荟萃分析中，COW 变异与缺血性卒中之间存在非显着正相关。