title: Temporal profile of recanalization after intravenous tissue plasminogen activator: selecting patients for rescue reperfusion techniques.
abstract: OBJECTIVE
  Intravenous thrombolysis in stroke achieves arterial recanalization in approximately 50% of cases. Determining temporal profile of recanalization may address patient selection and potential benefits of further rescue reperfusion techniques.
  
  
  METHODS
  We studied 179 consecutive intravenous tissue plasminogen activator (t-PA)-treated patients with intracranial artery occlusion. Continuous transcranial Doppler assessed recanalization (none-partial-complete) at 60 minutes (early), 120 minutes (delayed) after t-PA bolus, and 6 hours (late) from symptom onset. Outcomes were determined: National Institutes of Health Stroke Scale (NIHSS; 48-hour NIHSS) and 3-month modified Rankin Scale (mRS).
  
  
  RESULTS
  On admission, 68% of patients presented proximal middle cerebral artery occlusion, median NIHSS 17. Early recanalization was complete for 30 patients (17%), partial for 50 (28%), and none for 99 (55%). Delayed recanalization was complete for 56 patients (31%), partial for 39 (22%), and none for 84 (47%). Although early flow improvement was observed in up to 45% of patients, only 19% of patients with persistent occlusion (11% of total) presented delayed recanalization (odds ratio [OR] delayed/early recanalization, 0.16; 95% CI, 0.085 to 0.304; P<0.001). Among patients with persistent occlusion at 2 hours, only 13 (7% of total) presented late flow improvement (OR late/early recanalization, 0.09; 95% CI, 0.043 to 0.196; P<0.001). The few patients with late recanalization presented comparable median 48-hour NIHSS to those with early/delayed recanalization (3 versus 4.5; P=0.9) and much lower than those with persistent occlusion after 6 hours (3 versus 15; P=0.005). At 3 months, the rate of mRS < or =2 was not statistically different between patients with early/delayed versus late recanalization (55% versus 86%; P=0.12) but was lower if occlusion persisted 6 hours after onset (22%; P<0.001).
  
  
  CONCLUSIONS
  The majority of t-PA-induced recanalizations occur during the first hour after treatment. Recanalizations during the following hours are rare but still related to clinical improvement if achieved within 6 hours from onset. Rescue reperfusion techniques should be considered if flow improvement is not observed 60 minutes after t-PA bolus.
authors.affiliation: Unitat Neurovascular Hospital Vall d'Hebron, Barcelona, Spain. marcriboj@hotmail.com
authors.forename: Marc
authors.initials: M
authors.lastname: Ribo
authors.forename: José
authors.initials: J
authors.lastname: Alvarez-Sabín
authors.forename: Joan
authors.initials: J
authors.lastname: Montaner
authors.forename: Francisco
authors.initials: F
authors.lastname: Romero
authors.forename: Pilar
authors.initials: P
authors.lastname: Delgado
authors.forename: Marta
authors.initials: M
authors.lastname: Rubiera
authors.forename: Raquel
authors.initials: R
authors.lastname: Delgado-Mederos
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Molina
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001157:Arterial Occlusive Diseases / Q000000981:diagnostic imaging / Q000188:drug therapy; D002536:Cerebral Arteries; D005260:Female; D005343:Fibrinolytic Agents / Q000008:administration & dosage* / Q000627:therapeutic use; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D008875:Middle Aged; D018579:Patient Selection; D015424:Reperfusion / Q000379:methods*; D016879:Salvage Therapy; D015912:Thrombolytic Therapy; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000008:administration & dosage* / Q000627:therapeutic use; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial
chemical_list: D005343:Fibrinolytic Agents; D010959:Tissue Plasminogen Activator