title: Cerebral perfusion and blood pressure do not affect perihematoma edema growth in acute intracerebral hemorrhage.
abstract: OBJECTIVE
  The pathogenesis of perihematoma edema in intracerebral hemorrhage (ICH) is unknown but has been hypothesized to be ischemic. In the ICH Acutely Decreasing Arterial Pressure Trial (ICH ADAPT), perihematoma cerebral blood flow (CBF) was reduced but was unaffected by blood pressure (BP) reduction. Using ICH ADAPT data, we tested the hypotheses that edema growth is associated with reduced CBF and lower systolic BP.
  
  
  METHODS
  Noncontrast computed tomographic scans in patients with ICH were obtained at baseline, 2 hours, and 24 hours after randomization to target systolic BPs of <150 or <180 mm Hg. Computed tomography perfusion imaging was performed at 2 hours, and mean relative CBF was calculated in visibly edematous perihematoma tissue. Edema volumes were measured using a Hounsfield unit threshold of 5 to 23 at each time-point.
  
  
  RESULTS
  Patients were randomized at a median (interquartile range) of 7.4 (12.8) hours after onset. Treatment groups (n=34, <150 and n=33, <180 target) were balanced with respect to baseline systolic BP and acute ICH volume. Relative edema growth at 24 hours in the <150 group (0.11±0.19) was similar to that in the <180 group (0.09±0.16 mL; P=0.727). Absolute CBF was lower in the edematous region (35.67±13.1 mL/100 g per minute) when compared with that in the contralateral tissue (43.7±11.7 mL/100 g per minute; P<0.0001). Linear regression indicated that neither systolic BP change (β=-0.022; 95% confidence interval, -0.002 to 0.001) nor perihematoma relative CBF (β=-0.144; 95% confidence interval, -0.647 to 0.167) predicted edema growth.
  
  
  CONCLUSIONS
  Lower perihematoma CBF and BP treatment do not exacerbate edema growth. These data do not support a cytotoxic edema pathogenesis.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov. Unique identifier: NCT00963976.
authors.affiliation: From the Division of Neurology (R.M., B.G., L.G., M.K., T.J., B.B., K.B.) and Department of Diagnostic Imaging (D.E.), University of Alberta, Edmonton, Canada; Division of Neurology, University of British Columbia, Vancouver, Canada (N.A.); Division of Neurology, University of Ottawa, Ottawa, Canada (D.D.); and Department of Clinical Neurosciences, University of Calgary, Calgary, Canada (S.B.C., M.D.H., A.M.D.).
authors.forename: Rebecca
authors.initials: R
authors.lastname: McCourt
authors.forename: Bronwen
authors.initials: B
authors.lastname: Gould
authors.forename: Laura
authors.initials: L
authors.lastname: Gioia
authors.forename: Mahesh
authors.initials: M
authors.lastname: Kate
authors.forename: Shelagh B
authors.initials: SB
authors.lastname: Coutts
authors.forename: Dariush
authors.initials: D
authors.lastname: Dowlatshahi
authors.forename: Negar
authors.initials: N
authors.lastname: Asdaghi
authors.forename: Thomas
authors.initials: T
authors.lastname: Jeerakathil
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hill
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Demchuk
authors.forename: Brian
authors.initials: B
authors.lastname: Buck
authors.forename: Derek
authors.initials: D
authors.lastname: Emery
authors.forename: Kenneth
authors.initials: K
authors.lastname: Butcher
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D000959:Antihypertensive Agents / Q000008:administration & dosage; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D001795:Blood Pressure Determination; D001921:Brain / Q000098:blood supply* / Q000000981:diagnostic imaging; D001929:Brain Edema / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003287:Contrast Media; D005260:Female; D006406:Hematoma / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D000959:Antihypertensive Agents; D003287:Contrast Media
keywords: brain; cerebral hemorrhage; edema; hypertension; perfusion imaging