title: Vertebral artery hypoplasia is associated with a decrease in net vertebral flow volume.
abstract: The definition and clinical significance of vertebral artery hypoplasia (VAH) remain inconclusive. VAH has been proposed as a predisposing factor of posterior circulation ischemic stroke. The aim of this study was to determine a best cut-off diameter of vertebral artery (VA) for VAH and to investigate if unilateral VAH is associated with a decrease in net vertebral flow volume. Retrospective data of 1000 presumably healthy subjects free of cerebrovascular disease or apparent carotid atherosclerosis were analysed. We found that a VA diameter </=2.5mm is an ideal value to define VAH. The flow volume of the identified hypoplastic VA was remarkably low and the contralateral VA had only a slightly increased compensatory flow volume. The net VA flow volumes remained significantly and markedly lower in subjects with unilateral VAH (140.7+/-46.2mL/min) than those in subjects without VAH (190.1+/-54.5mL/min, p<0.001). Flow volume insufficiency of VA (defined as a net VA flow volume less than 100mL/min) occurred more frequently in individuals with VAH than in those without VAH (22.1% vs. 2.4%, p<0.001). Our study suggested that asymptomatic subjects with VAH had a significantly lower net VA flow volume and a higher frequency of VA flow insufficiency than the control group. (E-mail: hhhu@vghtpe.gov.tw).
authors.affiliation: Department of Neurology, Changhua Christian Hospital, Changhua, Taiwan.
authors.forename: Yen-Yu
authors.initials: YY
authors.lastname: Chen
authors.forename: A-Ching
authors.initials: AC
authors.lastname: Chao
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Hsu
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chung
authors.forename: Han-Hwa
authors.initials: HH
authors.lastname: Hu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001810:Blood Volume; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012189:Retrospective Studies; D018615:Ultrasonography, Doppler, Color; D014655:Vascular Resistance; D014711:Vertebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology*; D014715:Vertebrobasilar Insufficiency / Q000000981:diagnostic imaging / Q000473:pathology* / Q000503:physiopathology; D055815:Young Adult