title: Prediction of Delayed Cerebral Ischemia After Subarachnoid Hemorrhage Using Cerebral Blood Flow Velocities and Cerebral Autoregulation Assessment.
abstract: BACKGROUND
  The risk of delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) is associated with large cerebral artery vasospasm, but vasospasm is not a strong predictor for DCI. Assessment of cerebral autoregulation with transcranial Doppler (TCD) may improve the prediction of DCI. The aim of this prospective study was to assess the value of TCD-derived variables to be used alone or in combination for prediction of DCI.
  
  
  METHODS
  We included consecutive patients with low-grade aneurysmal SAH within 4 days of aneurysm rupture. Cerebral autoregulation was evaluated using the moving correlation coefficient Mx calculated from spontaneous fluctuations of cerebral blood flow velocities and arterial blood pressure. Transcranial color-coded sonography was performed to assess large artery vasospasm.
  
  
  RESULTS
  Thirty patients (19 women and 11 men; mean age ± SD 44.7 ± 12.1 years) were included. Twenty (66.7%) patients had vasospasm. DCI occurred in six (20%) patients after a median delay of 10 days (range 8-13 days). Cerebral autoregulation was impaired at baseline and at day 7 and then returned to normal at day 14. Neither cerebral autoregulation impairment nor large artery vasospasm alone was associated with DCI. In contrast, the combination of large artery vasospasm with worsening impairment of cerebral autoregulation from baseline to day 7 was significantly correlated to subsequent DCI (p = 0.007).
  
  
  CONCLUSIONS
  Early deterioration of cerebral autoregulation was strongly predictive of DCI in patients with large artery vasospasm after low-grade SAH. Our results suggest that consideration to both cerebral blood flow velocities and cerebral autoregulation may improve the prediction of DCI.
authors.affiliation: Department of Neurology, University Hospital of Toulouse, Toulouse, France, calviere.l@chu-toulouse.fr.
authors.forename: Lionel
authors.initials: L
authors.lastname: Calviere
authors.forename: Nathalie
authors.initials: N
authors.lastname: Nasr
authors.forename: Catherine
authors.initials: C
authors.lastname: Arnaud
authors.forename: Marek
authors.initials: M
authors.lastname: Czosnyka
authors.forename: Alain
authors.initials: A
authors.lastname: Viguier
authors.forename: Bernard
authors.initials: B
authors.lastname: Tissot
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Sol
authors.forename: Vincent
authors.initials: V
authors.lastname: Larrue
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D002545:Brain Ischemia / Q000000981:diagnostic imaging*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging*; D017585:Ultrasonography, Doppler, Transcranial; D020301:Vasospasm, Intracranial / Q000000981:diagnostic imaging*