title: Collateral circulation via the ophthalmic artery or leptomeningeal vessels is associated with impaired cerebral vasoreactivity in patients with symptomatic carotid artery occlusion.
abstract: OBJECTIVE
  In patients with carotid artery occlusion (CAO), collateral flow may reduce the risk of ischemic stroke. Collateral flow via the ophthalmic artery (OphthA) and flow via leptomeningeal vessels have been considered secondary collaterals, which are recruited only if the primary collateral circulation via the circle of Willis is insufficient. The aim of this study was to investigate whether patients with symptomatic CAO who have secondary in addition to primary collaterals have a worse flow state of the brain than those without secondary collaterals, as measured by vascular reactivity testing.
  
  
  METHODS
  We studied 70 patients with symptomatic CAO who were independent for their daily activities. In all patients, collateral circulation through the circle of Willis was present. Vascular reactivity, measured by means of transcranial Doppler sonography with carbogen inhalation, was compared between patients with and without secondary collaterals.
  
  
  RESULTS
  CO2 reactivity was lower in 64 patients with (mean +/- standard deviation 8 +/- 14%) than in 6 patients without secondary collaterals (33 +/- 18%) resulting in a mean difference of 24% (95% confidence interval 12-37%; p < 0.01).
  
  
  CONCLUSIONS
  Patients with symptomatic CAO with collateral circulation through the OphthA or through leptomeningeal vessels in addition to collaterals via the circle of Willis have a worse hemodynamic status of the brain than those with Willisian collaterals only. Therefore the presence of these collaterals may indicate insufficiency of collateral blood flow via the circle of Willis.
authors.affiliation: University Department of Neurology, University Medical Center Utrecht, Utrecht, The Netherlands. j.hofmeijer@neuro.azu.nl
authors.forename: J
authors.initials: J
authors.lastname: Hofmeijer
authors.forename: C J M
authors.initials: CJ
authors.lastname: Klijn
authors.forename: L J
authors.initials: LJ
authors.lastname: Kappelle
authors.forename: A C
authors.initials: AC
authors.lastname: Van Huffelen
authors.forename: J
authors.initials: J
authors.lastname: Van Gijn
mesh_terms: D000368:Aged; D001157:Arterial Occlusive Diseases / Q000503:physiopathology*; D002245:Carbon Dioxide / Q000502:physiology; D002340:Carotid Artery Diseases / Q000503:physiopathology*; D017536:Carotid Artery, Common; D002343:Carotid Artery, Internal; D002941:Circle of Willis / Q000503:physiopathology; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D008297:Male; D008576:Meningeal Arteries / Q000503:physiopathology*; D008875:Middle Aged; D009880:Ophthalmic Artery / Q000503:physiopathology*; D014664:Vasodilation
chemical_list: D002245:Carbon Dioxide