title: Toward a further elucidation: role of vertebral artery hypoplasia in acute ischemic stroke.
abstract: OBJECTIVE
  Congenital vertebral artery (VA) hypoplasia is an uncommon embryonic variation of posterior circulation. The frequency of this congenital variation was reported to be 2-6% from autopsy and angiograms. The aim of our study was to elucidate the role of VA hypoplasia in acute ischemic stroke.
  
  
  METHODS
  We examined 191 acute ischemic stroke patients (age 55.8 +/- 14.0 years). TOAST subtypes were determined. A cervical magnetic resonance angiogram was performed in every patient. A duplex study of bilateral VA with flow velocities and vessel diameter recording in the intertransverse (V2) segment was performed within 72 h after onset of ischemic stroke. The net VA flow volume was measured in each subject.
  
  
  RESULTS
  The overall incidence of a unilateral congenital hypoplastic VA was 11.51%, which was statistically higher especially in cases of brainstem/cerebellar infarction. Of these, subjects with VA hypoplasia had an etiological preponderance of the 'large-artery atherosclerosis' subtype and a topographic preponderance of ipsilateral posterior circulation infarction.
  
  
  CONCLUSIONS
  Based on our results, VA hypoplasia seemed a contributing factor of acute ischemic stroke, especially in posterior circulation territories.
authors.affiliation: Department of Neurology, Tao-Yuan General Hospital, Keelung General Hospital, Tao-Yuan City, Taiwan, ROC.
authors.forename: Yu-Ming
authors.initials: YM
authors.lastname: Chuang
authors.forename: Yuarn-Chung
authors.initials: YC
authors.lastname: Huang
authors.forename: Han-Haw
authors.initials: HH
authors.lastname: Hu
authors.forename: Ching-Yih
authors.initials: CY
authors.lastname: Yang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D050197:Atherosclerosis / Q000453:epidemiology; D002545:Brain Ischemia / Q000145:classification / Q000453:epidemiology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D000013:Congenital Abnormalities / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D020521:Stroke / Q000145:classification / Q000453:epidemiology / Q000503:physiopathology*; D014711:Vertebral Artery / Q000002:abnormalities*