Extending the Time for Thrombolysis in Emergency Neurological Deficits — Intra-Arterial | Clinical Trial - EXTEND-IA


The goal of the trial was to compare the role of endovascular therapy as an adjunct to intravenous (IV) thrombolysis in patients presenting with acute ischemic stroke within 4.5 hours of symptom onset, compared with IV thrombolysis alone.

Contribution to the Literature: The EXTEND-IA study suggests that endovascular therapy is superior in improving perfusion, neurological, and functional outcomes compared with IV thrombolysis alone in eligible patients presenting with acute ischemic stroke.

Study Design

Patients with acute ischemic stroke presenting within 4.5 hours of symptom onset were randomized to endovascular thrombectomy with the Solitaire FR stent retriever, along with IV alteplase (n = 35) or IV alteplase alone (n = 35).

Patient Population:

  • Total number of enrollees: 70
  • Duration of follow-up: 90 days
  • Mean patient age: 70 years
  • Percentage female: 51%
  • National Institutes of Health Stroke Scale (NIHSS) score (median): 15
  • Onset to tissue plasminogen activator (tPA): 135 minutes
  • Door-to-needle time: 45 minutes
  • Site of occlusion: internal carotid artery (ICA) 31%, middle cerebral artery (MCA)-M1: 54%, MCA-M2 15%

Inclusion criteria:

  • Acute ischemic stroke
  • Occlusion of the ICA or MCA and evidence of salvageable brain tissue and ischemic core of <70 ml on computed tomographic (CT) perfusion imaging
  • Premorbid modified Rankin score 0-1

Exclusion criteria:

  • Anatomy conducive to stent retriever device use

Principal Findings:

The trial was stopped early due to the positive results of the MR CLEAN trial. The primary outcome, perfusion at 24 hours, occurred in 100% of the endovascular + alteplase group versus 37% of the alteplase group (p < 0.0001).

Secondary outcomes:

  • Early neurological recovery: 80% vs. 37% (p = 0.0002)
  • mRS 0-2: 71% vs. 40% (p = 0.01)
  • Mortality: 9% vs. 20% (p = 0.18)
  • Symptomatic intracranial hemorrhage: 0% vs. 6% (p = 0.49)
  • In the endovascular arm, wire perforation observed in 2.9%; distal embolization in 5.7%


Among patients with acute ischemic stroke presenting within 4.5 hours of symptom onset due to proximal large arterial occlusion and evidence of salvageable brain tissue on CT perfusion imaging, the use of endovascular treatment with the Solitaire FR stent retriever as an adjunct to IV thrombolysis was superior to IV thrombolysis alone in improving distal perfusion.

Although this was a small trial, encouraging results were observed in neurological and functional outcomes. The presence of salvageable brain tissue, as determined by CT perfusion imaging in this trial, may be an important risk stratification method. In combination with other recent trials such as MR CLEAN, the results indicate that adjunctive endovascular treatment should be first-line therapy for eligible patients presenting with an acute ischemic stroke.


Campbell BC, Mitchell PJ, Kleinig TJ, et al., on behalf of the EXTEND-IA Investigators. Endovascular Therapy for Ischemic Stroke With Perfusion-Imaging Selection. N Engl J Med 2015;Feb 11:[Epub ahead of print].

Keywords: Endovascular Procedures, Carotid Artery, Internal, Follow-Up Studies, Intracranial Hemorrhages, Middle Cerebral Artery, National Institutes of Health (U.S.), Perfusion Imaging, Stents, Stroke

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