Variants of the circle of Willis in ischemic stroke patients

Purpose We aim to provide prevalence and pattern of anatomical variants of circle of Willis in over one thousand ischemic stroke patients compared to an age- and sex-matched control group, and to determine their role in the severity and in-hospital prognosis. Methods Two groups of neuroradiologists evaluated all vascular images of ischemic stroke patients and controls to identify anatomical variants using a preexisted classification. We collected data concerning patient characteristics, stroke severity on admission and discharge, in-hospital mortality, hemorrhagic transformation, acute treatment performed, and etiology. Results We included 1131 patients with acute ischemic stroke and 562 controls. Among stroke patients, 702 (62.1%) had one or more vascular variants, compared to 308 (54.8%) of the control group ( p