ESCAPE: Endovascular Therapy Reduces Mortality in Ischemic Stroke

February 11, 2015

Nashville, Tennessee — Rapid endovascular treatment improved functional outcomes and halved mortality in ischemic stroke patients with a proximal vessel occlusion in the ESCAPE trial.

The study was presented at the International Stroke Conference (ISC) 2015 on February 11 and published online simultaneously in the New England Journal of Medicine.

The Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times (ESCAPE) trial, along with two other studies presented at the same ISC session here — EXTEND-IA and SWIFT-PRIME — add to the recently published MR CLEAN trial. All four studies show convincing evidence of benefit for endovascular therapy in selected stroke patients.

"We showed a 25% absolute benefit in the amount of patients achieving functional independence when endovascular therapy was used," senior author of ESCAPE, Michael Hill, MD, University of Calgary, Alberta, Canada, commented to Medscape Medical News. "One in 4 additional people get back to an independent life with this treatment. This can be the difference between going to a nursing home and going home. And for younger patients it can mean they can go back to work."

Dr Hill said three key factors explained why endovascular treatment was successful in ESCAPE.

"You need appropriate imaging to select patients who are likely to benefit; fast times to treatment, which involves good teamwork — we treated patients 2 hours faster than in IMS-III — and the latest endovascular technology, which can achieve very high rates of reperfusion. These three factors need to be used together."

Presenting the results during the plenary session here, co-primary investigator Mayank Goyal, MD, also from the University of Calgary, concluded that "endovascular intervention is a highly effective procedure which saves lives, and dramatically reduces disability when patients are carefully selected."


In the phase 3 ESCAPE trial, 316 patients with ischemic stroke who had a large artery occlusion were randomly assigned to standard medical care, including tissue plasminogen activator (tPA) where appropriate, or standard medical care plus endovascular intervention. No specific device for the endovascular therapy was stipulated. but most patients (86%) used retrievable stents.

Multiphase computed tomographic (CT) angiography was used to exclude patients with a large infarct core or poor collateral circulation.

In the intervention group the median time from study CT to first reperfusion was 84 minutes.

The primary outcome — a shift analysis on the modified Rankin scale (mRS) — favored the endovascular therapy group with an odds ratio of 2.6 (95% confidence interval, 1.7 - 3.8).

In addition, significantly more patients in the endovascular group achieved a good functional outcome (90-day mRS score of 0 to 2) and mortality in the endovascular group was significantly lower.

ESCAPE: Main Results

Endpoint Endovascular Treatment Control P Value
mRS score of 0 - 2 at 90 d (%) 53.0 29.3 <.001
Mortality (%) 10.4 19.0 .04


Symptomatic intracerebral hemorrhage occurred in 3.6% of the intervention group vs 2.7% of control patients.

Dr Hill noted that the ESCAPE trial used a less specific method of selecting patients compared with EXTEND-IA and SWIFT-PRIME.

"While not as specific as perfusion imaging, CT angiography is very sensitive," he said. "It identifies those patients who benefit but will probably also include a few more that won't benefit. But it is generally faster than perfusion imaging."

12-Hour Window?

ESCAPE also differs from the other trials in that it allowed patients to be enrolled up to 12 hours after symptom onset.

"We had inclusion criteria out to 12 hours from symptom onset, but we only had 49 patients who were enrolled after 6 hours," Dr Hill commented. "So we don't have much data on the late group. However, while the result is not significant in these patients, it still suggests a major benefit of endovascular treatment, with a similar effect size as in the patients treated earlier."

He explained that so few late patients were included because these patients are less likely to have salvageable brain tissue on imaging. "But if the imaging data suggest there is salvageable tissue then the endovascular treatment seems to work just as well as in the earlier patients."

He added: "Although these results in the late patients are not significant I do think they can be applied to clinical practice. Maybe we'll have to pool some data on this."

Accessibility "Will Take Time"

Dr Hill estimates that 62,000 strokes occur each year in Canada, of which 85% are ischemic. Of these, one third will have a blockage of a major artery. "So potentially 10,000 to 12,000 patients could now be eligible for endovascular treatment in Canada. This number will be 10 times larger in the US."

But he pointed out that the harder issue will be accessibility. "It will take time to get this to happen. It is not just about technology — we need education about the imaging required and the speed and collaboration of the various members of the team working together."

Dr Hill said the 11 Canadian sites involved in ESCAPE would all be offering endovascular treatment from now on.

"To put these results into practice on a broader level we need to change the way we triage stroke patients," he said. "We need stroke patients suspected of having a major artery blockage directed to hospitals where there is a cath lab and a stroke team ready to receive them. This will take time to develop."

Supported by Covidien through an unrestricted grant to the University of Calgary. Also supported by the University of Calgary (Hotchkiss Brain Institute, the Department of Clinical Neurosciences and Calgary Stroke Program, and the Department of Radiology), Alberta Innovates–Health Solutions, the Heart and Stroke Foundation of Canada, and Alberta Health Services. Disclosures for coauthors available at

International Stroke Conference (ISC) 2015. Abstract LB1. Presented February 11, 2015.

N Engl J Med. Published online February 11, 2015. Abstract


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