title: Prevalence and prognosis of asymptomatic vertebral artery origin stenosis in patients with clinically manifest arterial disease.
abstract: OBJECTIVE
  The risk of ischemic stroke in patients with asymptomatic vertebral artery stenosis is unknown. We examined the incidence of posterior circulation ischemic stroke in patients with asymptomatic stenosis of the vertebral artery origin (VAo).
  
  
  METHODS
  We studied a hospital-based cohort of 3717 patients (median age, 60 years; interquartile range, 52 to 68 years) with atherosclerotic arterial disease enrolled in the Second Manifestations of ARTerial disease (SMART) study. We included patients in whom duplex ultrasound of the carotid artery and vertebral artery had been performed. Patients with symptomatic VAo stenosis or planned revascularization of the carotid artery or vertebral artery were excluded. Data were analyzed with Cox regression; hazard ratios were adjusted for age and vascular risk factors.
  
  
  RESULTS
  In 282 patients (7.6%), asymptomatic VAo stenosis>50% was diagnosed with duplex ultrasound. During a mean follow-up of 4.6 years (SD, 3.0), posterior circulation ischemic stroke occurred in 5 of the 282 patients with asymptomatic VAo stenosis at baseline (annual stroke rate, 0.4%) and in 12 of the 3435 patients without VAo stenosis (annual stroke rate, <0.1%). The risk of posterior circulation ischemic stroke was higher in patients with VAo stenosis than in patients without VAo stenosis (hazard ratio, 4.2; 95% CI, 1.4 to 13.1) and was further increased in patients with both VAo and carotid artery stenosis (hazard ratio, 10.5; 95% CI, 3.0 to 37.3). In multivariable analysis, this risk remained essentially the same.
  
  
  CONCLUSIONS
  Patients with atherosclerotic arterial disease and asymptomatic VAo stenosis have a higher risk of posterior circulation ischemic stroke than patients without such a stenosis, but the absolute risk remains low.
authors.affiliation: Utrecht Stroke Center, Department of Neurology, G 03.228, University Medical Center Utrecht, PO Box 85500, 3508 GA Utrecht, the Netherlands. a.compter@umcutrecht.nl
authors.forename: Annette
authors.initials: A
authors.lastname: Compter
authors.forename: H Bart
authors.initials: HB
authors.lastname: van der Worp
authors.forename: Ale
authors.initials: A
authors.lastname: Algra
authors.forename: L Jaap
authors.initials: LJ
authors.lastname: Kappelle
mesh_terms: D000368:Aged; D002545:Brain Ischemia / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011379:Prognosis; D012306:Risk; D020521:Stroke / Q000175:diagnosis / Q000453:epidemiology* / Q000209:etiology; D014715:Vertebrobasilar Insufficiency / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology*