title: Residual flow signals predict complete recanalization in stroke patients treated with TPA.
abstract: BACKGROUND
  Residual blood flow around thrombus prior to treatment predicts success of coronary thrombolysis. The authors aimed to correlate the presence of residual flow signals in the middle cerebral artery (MCA) with completeness of recanalization after intravenous tissue plasminogen activator (TPA).
  
  
  METHODS
  The authors studied consecutive patients treated with intravenous TPA therapy who had a proximal MCA occlusion on pretreatment transcranial Doppler (TCD). Patients were continuously monitored for 2 hours after TPA bolus. Absent residual flow signals correspond to the thrombolysis in brain ischemia (TIBI) 0 grade, and the presence of residual flow signals was determined as TIBI 1-3 flow grades. Complete recanalization was defined as flow improvement to TIBI grades 4-5.
  
  
  RESULTS
  Seventy-five patients with a proximal MCA occlusion had median pre-bolus NIHSS 16 (85% with > or = 10 points). TPA bolus was given at 141 +/- 56 minutes (median 120 minutes). Complete recanalization was observed in 25 (33%), partial in 23 (31%), and no early recanalization was seen in 27 (36%) patients within 2 hours after TPA bolus. Only 19% with absent residual flow signals (TIBI grade 0, n = 26) on pretreatment TCD had complete early recanalization. If pretreatment TCD showed the presence of any residual flow (TIBI 1-3, n = 49), 41% had complete recanalization within 2 hours of TPA bolus (P = .03).
  
  
  CONCLUSIONS
  Patients with detectable residual flow signals before IV TPA bolus are twice as likely to have early complete recanalization. Those with no detectable residual flow signals have less than 20% chance for complete early recanalization with intravenous TPA and may be candidates for intra-arterial therapies.
authors.affiliation: Stroke Program, University of Texas Medical School at Houston, TX, USA. lise.a.labiche@uth.tmc.edu
authors.forename: Lise A
authors.initials: LA
authors.lastname: Labiche
authors.forename: Marc
authors.initials: M
authors.lastname: Malkoff
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Alexandrov
mesh_terms: D000368:Aged; D001921:Brain / Q000098:blood supply*; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage*; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D007262:Infusions, Intravenous; D008297:Male; D020768:Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000187:drug effects / Q000503:physiopathology*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012039:Regional Blood Flow / Q000187:drug effects; D012815:Signal Processing, Computer-Assisted; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage*; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator