title: Relationship between vertebral artery hypoplasia and posterior circulation stroke in Chinese patients.
abstract: BACKGROUND
  Vertebral artery hypoplasia (VAH), which has been found in about 10 % of normal individuals, does not produce symptoms but may be associated with an increased risk of cerebral posterior circulation ischemic (PCI) stroke. The aims of this study were to determine the prevalence of VAH in Chinese patients with cerebral infarction and investigate whether VAH is an independent risk factor for PCI stroke.
  
  
  METHODS
  The medical records of 841 Chinese stroke patients were reviewed retrospectively. All patients underwent either cervical contrast-enhanced magnetic resonance angiography (CE-MRA) or cervical computed tomography angiography (CTA). There is no standard definition of VAH; we defined it as a vertebral artery < 2 mm in diameter and the whole artery was slim or absent on CE-MRA or CTA. Univariate and multivariate logistic regression analyses were performed to identify significant independent risk factors for PCI stroke.
  
  
  RESULTS
  There were 230 patients (27.3 %) diagnosed with PCI stroke and 91 patients diagnosed with VAH (10.8 %). Multivariate logistic regression analysis showed that VAH, male gender, and stenosis of the posterior circulation were independent risk factors for PCI stroke.
  
  
  CONCLUSIONS
  Our results show that VAH is not rare in Chinese patients with stroke and that its presence increases the risk of PCI stroke.
authors.affiliation: Department of Neurology, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, People's Republic of China.
authors.forename: Xiao-Yue
authors.initials: XY
authors.lastname: Hu
authors.forename: Zheng-Xi
authors.initials: ZX
authors.lastname: Li
authors.forename: Hui-Qin
authors.initials: HQ
authors.lastname: Liu
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Meng-Li
authors.initials: ML
authors.lastname: Wei
authors.forename: Shan
authors.initials: S
authors.lastname: Fang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Hui
authors.initials: H
authors.lastname: Pan
authors.forename: Jin-Xiu
authors.initials: JX
authors.lastname: Huang
authors.forename: Yi-Min
authors.initials: YM
authors.lastname: Zhu
authors.forename: Jian-Ren
authors.initials: JR
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015984:Causality; D002533:Cerebral Angiography / Q000706:statistics & numerical data*; D002681:China / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006801:Humans; D020762:Infarction, Posterior Cerebral Artery / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D014711:Vertebral Artery / Q000000981:diagnostic imaging* / Q000473:pathology*; D014715:Vertebrobasilar Insufficiency / Q000175:diagnosis* / Q000453:epidemiology*; D055815:Young Adult