title: Autoregulation of cerebral blood flow is preserved in primary intracerebral hemorrhage.
abstract: OBJECTIVE
  Treatment of acute hypertension after intracerebral hemorrhage (ICH) is controversial. In the context of disrupted cerebral autoregulation, blood pressure (BP) reduction may cause decreased cerebral blood flow (CBF). We used serial computed tomography perfusion to test the hypothesis that CBF remains stable after BP reduction.
  
  
  METHODS
  Patients recruited within 72 hours of ICH were imaged with computed tomography perfusion before and after BP treatment. Change in perihematoma relative (r) CBF after BP treatment was the primary end point.
  
  
  RESULTS
  Twenty patients were imaged with computed tomography perfusion at a median (interquartile range) time from onset of 20.2 (25.7) hours and reimaged 2.1 (0.5) hours later, after BP reduction. Mean systolic BP in treated patients (n=16; 4 untreated as BP<target at baseline) decreased significantly between the first (168 ± 21 mm Hg) and second (141 ± 19 mm Hg; P<0.0001) computed tomography perfusion scans. The primary end point of rCBF was not affected by BP reduction (pretreatment=0.89 ± 0.11; post-treatment=0.87 ± 0.11 mL/100 g per minute; P=0.37). Linear regression showed no relationship between changes in systolic BP and perihematoma rCBF (β=0.001 [-0.002 to 0.003]; P=0.63).
  
  
  CONCLUSIONS
  CBF remained stable after acute BP reduction, suggesting some preservation of cerebral autoregulation.
authors.affiliation: Division of Neurology, University of Alberta, 8440 112th St, Edmonton, Alberta, Canada T6G 2B7.
authors.forename: Bronwen
authors.initials: B
authors.lastname: Gould
authors.forename: Rebecca
authors.initials: R
authors.lastname: McCourt
authors.forename: Negar
authors.initials: N
authors.lastname: Asdaghi
authors.forename: Dariush
authors.initials: D
authors.lastname: Dowlatshahi
authors.forename: Thomas
authors.initials: T
authors.lastname: Jeerakathil
authors.forename: Mahesh
authors.initials: M
authors.lastname: Kate
authors.forename: Shelagh B
authors.initials: SB
authors.lastname: Coutts
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Demchuk
authors.forename: Ashfaq
authors.initials: A
authors.lastname: Shuaib
authors.forename: Derek
authors.initials: D
authors.lastname: Emery
authors.forename: Kenneth
authors.initials: K
authors.lastname: Butcher
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000494:pharmacology / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002543:Cerebral Hemorrhage / Q000150:complications / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000209:etiology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed
chemical_list: D000959:Antihypertensive Agents
keywords: cerebral blood flow; hypertension; intracerebral hemorrhage