Association of Vertebral Artery Hypoplasia and Vertebrobasilar Cerebrovascular Accident

Background and Objectives: Vertebral artery hypoplasia (VAH) is a controversial risk factor for cerebral infarction. The aim of this study was to analyze the prevalence of vertebral artery hypoplasia and to evaluate its association with vertebrobasilar cerebrovascular accidents. Materials and Methods: The study was conducted in the Neurology Departments of the Republican Vilnius University Hospital from 2015 to 2020. Data of 742 subjects (133 patients with posterior circulation infarction or vertebral artery syndrome (PCI/VAS), 80 patients with anterior circulation infarction (ACI) and 529 control subjects with no symptoms of cerebrovascular accident) were analyzed. Ultrasound examination of the extracranial internal carotid and vertebral arteries (VA) was performed, risk factors were recorded. Results: The mean age of the subjects was 64.51 ± 13.02 years. In subjects with PCI/VAS the diameter of VA was smaller, and the prevalence of VAH was higher compared to those in subjects with ACI and in the control group. A higher degree of VAH in subjects younger than 65 years of age increased the risk of PCI/VAS. Subjects with non-dominant VA diameter of 2.7-2.9 mm had 2.21 times higher risk of PCI/VAS, subjects with non-dominant VA diameter of 2.5-2.6 mm had 2.36 times higher risk of PCI/VAS, and subjects with non-dominant VA diameter of 2.2-2.4 mm had 4.12 times higher risk of PCI/VAS compared with subjects with non-dominant VA diameter of ≥3 mm. Among patients with PCI/VAS those with VAH had lower rates of ischemic heart disease compared with patients with normal VA diameter. There was no difference in the rates of other risk factors between PCI/VAS patients with and without VAH. Conclusions: Vertebral artery hypoplasia is not a rare finding in individuals without symptoms of cerebrovascular accident, but more frequent in patients with vertebrobasilar cerebral infarction or vertebrobasilar artery syndrome. Vertebral artery hypoplasia can be considered a risk factor for posterior circulation infarction in subjects under 65 years of age.