title: Effect of collateral blood flow on patients undergoing endovascular therapy for acute ischemic stroke.
abstract: OBJECTIVE
  Our aim was to determine the relationships between angiographic collaterals and diffusion/perfusion findings, subsequent infarct growth, and clinical outcome in patients undergoing endovascular therapy for ischemic stroke.
  
  
  METHODS
  Sixty patients with a thrombolysis in cerebral infarction (TICI) score of 0 or 1 and internal carotid artery/M1 occlusion at baseline were evaluated. A blinded reader assigned a collateral score using a previous 5-point scale, from 0 (no collateral flow) to 4 (complete/rapid collaterals to the entire ischemic territory). The analysis was dichotomized to poor flow (0-2) versus good flow (3-4). Collateral score was correlated with baseline National Institutes of Health Stroke Scale, diffusion-weighted imaging volume, perfusion-weighted imaging volume (Tmax ≥6 seconds), TICI reperfusion, infarct growth, and modified Rankin Scale score at day 90.
  
  
  RESULTS
  Collateral score correlated with baseline National Institutes of Health Stroke Scale (P=0.002) and median volume of tissue at Tmax ≥6 seconds (P=0.009). Twenty-nine percent of patients with poor collateral flow had TICI 2B-3 reperfusion versus 65.5% with good flow (P=0.009). Patients with poor collaterals who reperfused (TICI 2B-3) were more likely to have a good functional outcome (modified Rankin Scale score 0-2 at 90 days) compared with patients who did not reperfuse (odds ratio, 12; 95% confidence interval, 1.6-98). There was no difference in the rate of good functional outcome after reperfusion in patients with poor collaterals versus good collaterals (P=1.0). Patients with poor reperfusion (TICI 0-2a) showed a trend toward greater infarct growth if they had poor collaterals versus good collaterals (P=0.06).
  
  
  CONCLUSIONS
  Collaterals correlate with baseline National Institutes of Health Stroke Scale, perfusion-weighted imaging volume, and good reperfusion. However, target mismatch patients who reperfuse seem to have favorable outcomes at a similar rate, irrespective of the collateral score.
  
  
  BACKGROUND
  http://www.clinicaltrials.gov. Unique identifier: NCT01349946.
authors.affiliation: From Stanford Stroke Center, Stanford University School of Medicine, Palo Alto, CA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Marks
authors.forename: Maarten G
authors.initials: MG
authors.lastname: Lansberg
authors.forename: Michael
authors.initials: M
authors.lastname: Mlynash
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Olivot
authors.forename: Matus
authors.initials: M
authors.lastname: Straka
authors.forename: Stephanie
authors.initials: S
authors.lastname: Kemp
authors.forename: Ryan
authors.initials: R
authors.lastname: McTaggart
authors.forename: Manabu
authors.initials: M
authors.lastname: Inoue
authors.forename: Greg
authors.initials: G
authors.lastname: Zaharchuk
authors.forename: Roland
authors.initials: R
authors.lastname: Bammer
authors.forename: Gregory W
authors.initials: GW
authors.lastname: Albers
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D002533:Cerebral Angiography / Q000379:methods; D002560:Cerebrovascular Circulation / Q000502:physiology*; D003097:Collateral Circulation / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D057510:Endovascular Procedures / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055420:Perfusion Imaging; D012044:Regression Analysis; D020521:Stroke / Q000175:diagnosis / Q000503:physiopathology* / Q000628:therapy*; D017131:Thrombectomy / Q000379:methods; D015912:Thrombolytic Therapy / Q000379:methods; D016896:Treatment Outcome
keywords: angiography; collateral circulation; magnetic resonance imaging; stroke