title: Collateral flow predicts response to endovascular therapy for acute ischemic stroke.
abstract: OBJECTIVE
  Collaterals sustain the penumbra before recanalization and offset infarct growth, yet the influence of baseline collateral flow on recanalization after endovascular therapy remains relatively unexplored.
  
  
  METHODS
  We analyzed consecutive patients who received endovascular therapy for acute cerebral ischemia from 2 distinct study populations. We assessed the relationship between pretreatment collateral grade and vascular recanalization (Thrombolysis In Myocardial Ischemia [TIMI] scale). In addition, we assessed infarct growth on serial MRI.
  
  
  RESULTS
  A total of 222 patients was included, 138 from the United States and 84 from South Korea. Complete revascularization occurred in 14.1% (11 of 78) patients with poor pretreatment collateral grades, whereas it was observed in 25.2% (26 of 103) patients with good collaterals and 41.5% (17 of 41) patients with excellent collaterals (P<0.001). This relationship was consistently observed in both study populations, although the mode of endovascular therapy was different between them. After adjustment for other factors, including mode of endovascular therapy, prior use of intravenous tissue plasminogen activator, and site of occlusion, pretreatment collateral grade was independently associated with recanalization. When revascularization was achieved, greater infarct growth occurred in patients with poor collaterals than in those with good collaterals (P=0.012).
  
  
  CONCLUSIONS
  Our data indicate that angiographic collateral grade determines the recanalization rate after endovascular revascularization therapy. When therapeutic revascularization was achieved, beneficial effects were not observed in patients with poor collaterals. Angiographic collateral grade may therefore help guide treatment decision-making in acute cerebral ischemia.
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University, Seoul, South Korea.
authors.forename: Oh Young
authors.initials: OY
authors.lastname: Bang
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Saver
authors.forename: Suk Jae
authors.initials: SJ
authors.lastname: Kim
authors.forename: Gyeong-Moon
authors.initials: GM
authors.lastname: Kim
authors.forename: Chin-Sang
authors.initials: CS
authors.lastname: Chung
authors.forename: Bruce
authors.initials: B
authors.lastname: Ovbiagele
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: David S
authors.initials: DS
authors.lastname: Liebeskind
mesh_terms: D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D002548:Cerebral Revascularization / Q000379:methods; D003097:Collateral Circulation / Q000502:physiology*; D057510:Endovascular Procedures / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011859:Radiography; D012039:Regional Blood Flow / Q000502:physiology; D020521:Stroke / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D015912:Thrombolytic Therapy / Q000379:methods