title: Collateral failure? Late mechanical thrombectomy after failed intravenous thrombolysis.
abstract: OBJECTIVE
  Collaterals may compensate for reduced blood flow in acute ischemic stroke, yet endurance and quality of collateral perfusion may vary. Collateral sustenance of penumbra may falter after initial recruitment, resulting in progressive ischemia and clinical deficits. Delayed collateral failure may extend the time window for revascularization, even after failed intravenous thrombolysis.
  
  
  METHODS
  A 76-year-old woman returned to normal from National Institutes of Health Stroke Scale (NIHSS) score of 18 following intravenous thrombolysis, despite persistent occlusion of the left middle cerebral artery. Subsequent deterioration was successfully reversed with mechanical thrombectomy almost 14 hours after symptom onset.
  
  
  CONCLUSIONS
  Early clinical improvement or deterioration may reflect collateral perfusion, not necessarily recanalization or reocclusion. The definition of collateral failure must incorporate the expected role and endurance of collaterals. Further investigation of collateral pathophysiology may reveal predictive clinical or imaging features and disclose collateral therapeutic approaches to augment revascularization.
authors.affiliation: Department of Neurology, UCLA Stroke Center, Los Angeles, California 90095, USA. davidliebeskind@yahoo.com
authors.forename: David S
authors.initials: DS
authors.lastname: Liebeskind
authors.forename: Doojin
authors.initials: D
authors.lastname: Kim
authors.forename: Sidney
authors.initials: S
authors.lastname: Starkman
authors.forename: Kelly
authors.initials: K
authors.lastname: Changizi
authors.forename: Arbi G
authors.initials: AG
authors.lastname: Ohanian
authors.forename: Reza
authors.initials: R
authors.lastname: Jahan
authors.forename: Fernando
authors.initials: F
authors.lastname: Viñuela
mesh_terms: D000208:Acute Disease; D000368:Aged; D001921:Brain / Q000098:blood supply / Q000473:pathology / Q000601:surgery; D002533:Cerebral Angiography; D002560:Cerebrovascular Circulation; D003097:Collateral Circulation; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy* / Q000473:pathology / Q000601:surgery*; D018810:Magnetic Resonance Angiography; D008279:Magnetic Resonance Imaging; D017131:Thrombectomy; D015912:Thrombolytic Therapy; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
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