Over the past decade, endovascular therapy has been increasingly studied as a potential intervention for ischemic stroke. However, prior randomized trials of endovascular therapy in ischemic stroke failed to demonstrate clinical benefit. The prevailing thought from those studies was that patients most likely to benefit from endovascular therapy were not carefully selected. Specifically, patients did not receive rapid imaging to demonstrate a proximal occlusion and to rule out a large area of infarction prior to inclusion in those studies. In addition, the newer generations of thrombectomy devices are thought to be superior to the devices that were used in the prior negative studies.

Clinical Question

In select patients with acute ischemic stroke who underwent head CT/CTA to demonstrate a proximal intracranial occlusion in the anterior circulation, small area of infarction and good collateral circulation, does endovascular therapy improve functional outcome compared to usual care for acute ischemic stroke?


Adults > 18 with disabling acute ischemic stroke (NIHSS >5), randomized within 12 hours of onset of stroke symptoms, and pre-stroke independent functional status. Included patients had to have a non-contrast head CT demonstrating a small infarct core (ASPECTS score 6-10), CTA had to demonstrate proximal MCA occlusion (with or without associated ICA occlusion), and good collateral circulation (> 50% filling of MCA territory). In addition, time from NCHCT to groin puncture had to be < 60 minutes, and time to reperfusion had to be less than 90 minutes.


Reperfusion via endovascular therapy in addition to usual stroke care.


Usual stroke care based on current standard of care for acute ischemic stroke: e.g IV alteplase if indicated, BP management, admission to dedicated stroke unit.


Primary: Change in modified Rankin score (mRs) at 90 days.
Secondary: Proportion of patients with functional independence at 90 days, mortality, complications such as intracranial hemorrhage and angiography complications.


Multicenter, prospective, randomized, open label, controlled trial with blinded outcome evaluation.


< 18, patient’s with acute ischemic stroke not meeting the inclusion criteria, suspected intracranial dissection, pregnancy, IV contrast allergy.

Primary Results

Critical Findings

  • Primary Outcome: OR for improvement of 1 point on modified Rankin scale was 2.6, favoring intervention group (95% CI: 1.7-3.8; P<0.0001)
  • Secondary Outcomes
    • Functional independence at 90 days: 53% intervention group vs 29% control group
    • Mortality at 90 days: 10.4% intervention group vs 19% control group
    • Symptomatic intracranial hemorrhage: 3.6% intervention group vs 2.7% control group

Primary Results: 

  • 316 patients underwent randomization, 1 excluded due to improper consent
  • 165 patients in intervention arm (endovascular treatment + usual care)
  • 150 patients in control arm (usual care only)
  • Intervention and control group were well matched in terms of age, gender, co-morbidities and stroke severity.


  • Multicenter trial
  • Clinically relevant outcomes: independent functional status at 90 days, mortality.
  • Follow up was complete
  • Intervention and control groups well balanced in terms of demographics (age, co-morbidities, NIHSS score)


  • Discontinued early after results of MR CLEAN trial (originally planned to enroll 500pts)
  • VERY select group of stroke patients given the strict inclusion criteria limits generalizability to all stroke patients
  • Important to note that major stroke centers were only able to enroll 4 pts/month on average
  • The level of efficiency and expertise is well beyond the capabilities of most academic tertiary medical centers currently.

Other Issues

Overall, this is a well-designed study, showing that endovascular therapy can be beneficial in very select patients with acute ischemic stroke in highly specialized endovascular therapy stroke centers. However, it is imperative to note the extremely limited population of stroke patients that met the inclusion criteria for this study. Prior studies of endovascular treatment in acute ischemic stroke have had negative outcomes in less select populations, so we should careful about indication creep (applying the results of this study to a different patient group than was included).

Author's Conclusions

“In conclusion, the ESCAPE trial, in which fast and efficient workflow, innovative imaging, and effective thrombectomy devices were used, provides evidence of the benefit of endovascular treatment in patients with moderate-to-severe ischemic stroke.”

Our Conclusions

In a very select group of patients with ischemic stroke (proximal anterior circulation occlusion, small infarcted core, and good collateral flow), rapid and efficient endovascular therapy in addition to usual stroke care resulted in improved functional outcome and decreased mortality at 90 days compared to usual stroke care alone.

Potential Impact To Current Practice

Significant; this study used imaging technology to identify a subset of patients with acute ischemic stroke that may benefit from endovascular reperfusion. Rather than simply relying on time from onset of ischemic symptoms to determine whether a patient is a candidate for IV thrombolytics, early workflow for management of acute ischemic stroke should also involve early imaging to determine whether the patient is an appropriate candidate for endovascular reperfusion.

Bottom Line

In carefully selected patients with acute ischemic stroke (proximal occlusion, small infarcted core, and good collaterals), rapid endovascular reperfusion + usual care improved functional outcome and mortality compared to usual care alone.

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