title: Assessment of flow changes in the circle of Willis after stenting for severe internal carotid artery stenosis.
abstract: OBJECTIVE
  To assess flow velocities in the cerebral arteries after carotid artery stenting (CAS) in patients with unilateral versus bilateral lesions and analyze velocities in patients with neurological complications after CAS.
  
  
  METHODS
  Ninety-two patients (68 men; mean age 63.2 +/- 8.4 years, range 44-82) with internal carotid artery (ICA) stenoses were divided according to unilateral (group I, n = 72) or bilateral (group II, n = 20) disease. Fifty age- and gender-matched patients without lesions in the extra- or intracranial arteries served as a control group. Transcranial color-coded Doppler ultrasound was performed prior to and within 24 hours after CAS in the test groups; systolic velocities were assessed ipsilateral (i) and contralateral (c) to the CAS site in the middle cerebral artery (MCA) and anterior cerebral artery (ACA).
  
  
  RESULTS
  Collateral flow via the anterior communicating artery (ACoA) was found in all group-II patients and 90% of group-I patients. After CAS, collateral flow through the ACoA ceased, and the velocity increased by 26% in the iMCA in group I compared to controls (p < 0.001). In group II, iMCA flow increased by 30% (p < 0.001) and flow via the ACoA (p < 0.001) increased, resulting in normalization of cMCA velocities (p = 0.928). In 89 (96.7%) subjects, CAS was uncomplicated. Hyperperfusion syndrome occurred in 2 (2.2%) patients, both with bilateral ICA stenoses; 1 (1.1%) transient ischemic attack was seen in a patient with unilateral disease. In the patients with hyperperfusion syndrome, the MCA velocities were 2.7- and 7.4-fold higher, respectively, versus before CAS and 2-fold higher than in controls.
  
  
  CONCLUSIONS
  Uncomplicated CAS results in an iMCA velocity increase >25% compared to controls. MCA velocities in hyperperfusion syndrome were greatly increased versus before CAS and in controls.
authors.affiliation: Department of Cardiac and Vascular Diseases, Institute of Cardiology, Jagiellonian University School of Medicine, Krakow, Poland. kablakziembicka@op.pl
authors.forename: Anna
authors.initials: A
authors.lastname: Kablak-Ziembicka
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Przewlocki
authors.forename: Piotr
authors.initials: P
authors.lastname: Pieniazek
authors.forename: Piotr
authors.initials: P
authors.lastname: Musialek
authors.forename: Rafal
authors.initials: R
authors.lastname: Motyl
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Moczulski
authors.forename: Wieslawa
authors.initials: W
authors.lastname: Tracz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery; D016893:Carotid Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D002941:Circle of Willis / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D015607:Stents; D017585:Ultrasonography, Doppler, Transcranial