title: Impact of reperfusion after 3 hours of symptom onset on tissue fate in acute cerebral ischemia.
abstract: BACKGROUND
  Reperfusion of penumbral tissue is a promising strategy for treatment of acute cerebral ischemia more than 3 hours from symptom onset. However, there has been only sparse direct evidence that reperfusion after 3 hours prevents infarct growth.
  
  
  METHODS
  We analyzed clinical and serial magnetic resonance imaging (MRI) data on patients who received endovascular recanalization therapy 3-12 hours after last known well time. Multimodal MRIs were acquired pretreatment, early (1-20 hours), and late (2-7 days) after treatment. Degree of recanalization was assessed on end of procedure catheter angiogram, degree of reperfusion on early posttreatment perfusion MRI, and infarct growth by analysis of diffusion lesion volumes on pretreatment and late MRIs.
  
  
  RESULTS
  Twenty-seven (12 men, 15 women) underwent endovascular recanalization procedures at 6.0 +/- 2.1 hours (range, 3.0-11.5 hours) after last known well time. Immediate posttreatment perfusion lesion (Tmax > or =4 seconds) volume correlated strongly with infarct growth (r= .951, P < .001), exceeding the correlations of vessel recanalization score (r=-.198, P= .446) and pretreatment diffusion-perfusion mismatch volume (r= .518, P= .033). Without reperfusion, enlargement of DWI lesion volume was observed in all patients, and extent of enlargement depended on volume of immediate posttreatment perfusion defects.
  
  
  CONCLUSIONS
  Our data indicate that posttreatment reperfusion is the major determinant of threatened tissue outcome, and suggest reperfusion even after 3 hours of symptom onset can alter tissue fate over a wide range of mismatch volumes.
authors.affiliation: Department of Neurology, University of California, Los Angeles, CA, USA.
authors.forename: Oh Young
authors.initials: OY
authors.lastname: Bang
authors.forename: David S
authors.initials: DS
authors.lastname: Liebeskind
authors.forename: Brian H
authors.initials: BH
authors.lastname: Buck
authors.forename: Sa Rah
authors.initials: SR
authors.lastname: Yoon
authors.forename: Jeffry R
authors.initials: JR
authors.lastname: Alger
authors.forename: Bruce
authors.initials: B
authors.lastname: Ovbiagele
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Saver
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000098:blood supply* / Q000473:pathology* / Q000601:surgery; D002545:Brain Ischemia / Q000473:pathology* / Q000601:surgery / Q000628:therapy*; D002533:Cerebral Angiography; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015424:Reperfusion; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult