title: Cerebrovascular reactivity after treatment of unruptured intracranial aneurysms--A transcranial Doppler sonography and acetazolamide study.
abstract: BACKGROUND
  Cerebrovascular reactivity (CVR) is defined as the change in cerebral blood flow, or blood velocity, in response to a vasoactive stimulus. There is a possible association between impaired CVR and vasospasm after aneurysmal subarachnoid hemorrhage. Most studies on CVR and vasospasm have used healthy subjects as reference. However, due to potential different vascular features, CVR in persons with intracranial aneurysms may differ from CVR in healthy subjects. Therefore, our aim was to examine CVR in patients with unruptured intracranial aneurysms (UIA).
  
  
  METHODS
  CVR was examined in 37 patients in the first postoperative week after treatment for UIA, using acetazolamide (AZ) test with transcranial Doppler monitoring of blood flow velocities.
  
  
  RESULTS
  Mean blood flow velocity in the middle cerebral arteries was 58.5 (SD 12.8) cm/s at baseline, and 94.3 (SD 19.5) cm/s after stimulation with AZ. Mean CVR was 62.6 (SD 16.8) %. There was no significant difference when comparing right and left sides, and treated and untreated sides. A simple regression analysis suggested that CVR increased with 0.7% points for each year a patient aged (p=0.004). However, the significance disappeared in a multiple analysis (increase of 0.6% points per year, p=0.055). Other possible influencing factors (gender, smoking, hypertension, body mass index, aneurysm location and treatment modality) were not significantly associated with CVR.
  
  
  CONCLUSIONS
  CVR in patients with UIA is not different from normal values reported in healthy subjects, and does not indicate a systemically impaired vascular system in patients with UIA. We suggest that CVR in age and gender matched healthy controls can be used as reference for persons with intracranial aneurysms.
authors.affiliation: Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway; Department of Neurosurgery, Haukeland University Hospital, 5021 Bergen, Norway. Electronic address: marianne.boethun@gmail.com.
authors.forename: Marianne Lundervik
authors.initials: ML
authors.lastname: Bøthun
authors.affiliation: Department of Global Public Health and Primary Health Care, University of Bergen, 5020 Bergen, Norway.
authors.forename: Øystein Ariansen
authors.initials: ØA
authors.lastname: Haaland
authors.affiliation: Department of Neurology, Haukeland University Hospital, 5021 Bergen, Norway.
authors.forename: Nicola
authors.initials: N
authors.lastname: Logallo
authors.affiliation: Department of Neurosurgery, Haukeland University Hospital, 5021 Bergen, Norway.
authors.forename: Frode
authors.initials: F
authors.lastname: Svendsen
authors.affiliation: Department of Neurology, Haukeland University Hospital, 5021 Bergen, Norway; Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway.
authors.forename: Lars
authors.initials: L
authors.lastname: Thomassen
authors.affiliation: Department of Neurosurgery, Haukeland University Hospital, 5021 Bergen, Norway; Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway.
authors.forename: Christian A
authors.initials: CA
authors.lastname: Helland
mesh_terms: D000086:Acetazolamide / Q000494:pharmacology / Q000627:therapeutic use*; D000328:Adult; D001783:Blood Flow Velocity / Q000187:drug effects / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*
chemical_list: D000086:Acetazolamide
keywords: Acetazolamide; Blood flow velocity; Cerebral hemodynamics; Cerebrovascular reactivity; Intracranial aneurysm; Transcranial Doppler sonography