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Researchers find new therapy benefits stroke patients

Lum CheemunFebruary 11, 2015 Researchers at The Ottawa Hospital and the University of Ottawa have contributed to an international randomized controlled trial showing that a clot retrieval procedure, known as endovascular treatment (ET), can dramatically improve patient outcomes after an acute ischemic stroke. The study, led by researchers at the University of Calgary’s Hotchkiss Brain Institute (HBI), shows a dramatic improvement in outcomes and a reduction in deaths from stroke. The results of this study were published in the Feb. 11 online edition of the New England Journal of Medicine (NEJM).

Overall, positive outcomes for patients increased from 30 per cent to 55 per cent.   In many cases, instead of suffering major neurological disability, patients went home to resume their lives. The overall mortality rate was reduced from two in 10 patients for standard treatment of care to one in 10 patients – a 50 per cent reduction with ET.

“This study represents a major advance in the treatment of acute stroke,” said Dr. Cheemun Lum, an interventional neuroradiologist at The Ottawa Hospital, who ran the study in Ottawa along with stroke neurologist Dr. Dar Dowlatshahi. “These are patients presenting with the worst stroke symptoms and the biggest clots. With stroke, it is a race against time. We now know that quick imaging and fast removal of the clot using radiological guidance is best for patients with these types of blockages.”

Drs. Lum and Dowlatshahi are also affiliated with the University of Ottawa and the Ottawa Hospital Research Institute.

The clinical trial, known as ESCAPE (Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times), shows there is a marked reduction in both disability and death among patients who receive ET for acute ischemic stroke. Ischemic stroke is caused by a sudden blockage of an artery to the brain that deprives the brain of critical nutrients, such as glucose and oxygen. Currently, the international standard of care based on Canadian, U.S. and European guidelines is to administer a drug called tPA when appropriate. Known as a ‘clot buster’, the drug dissolves the blood clot.

In the ESCAPE trial, 316 patients who fit the criteria for ET and arrived for treatment within 12 hours of their stroke were randomized to standard medical care (which included the clot-busting drug tPA where appropriate) or standard medical care plus ET.

ET is performed by inserting a thin tube into the artery in the groin, through the body, and into the brain vessels to the clot. This is done under image-guided care using an X-ray. The clot is then removed by a retrievable stent and pulled out, restoring blood flow to the brain.

Endovascular treatments were first developed in the 1990s, but ET has only recently been technically possible. The ESCAPE team says the success of the trial can be credited to very fast treatment and the use of brain and blood vessel imaging. In ESCAPE, researchers were on average two hours faster in opening the blocked blood vessels than in previously reported trials.

ESCAPE is the second ET trial that demonstrates the efficacy of the treatment and the first trial to demonstrate reduced mortality. The previous trial, known as MR. CLEAN (Multi center Randomized Clinical trial of Endovascular treatment for Acute ischemic stroke in the Netherlands), was published in December 2014.

The study included 22 sites worldwide and patients in the U.S., U.K., Ireland and South Korea. Canada had 11 participating hospitals and enrolled two-thirds of the patients.

In addition to being published online, the results of this landmark study will be published in the March 19 print edition of NEJM and presented at the American Heart Association’s International Stroke Conference in Nashville, Tenn.

The study was funded by The Heart and Stroke Foundation of Canada, Alberta Innovates-Health Solutions and Medtronic, along with generous donations to the HBI Stroke Team and the Calgary Stroke Program. The Ottawa Hospital Foundation supports all research at The Ottawa Hospital, including this trial.


Foothills Medical Centre: Calgary, Alta.
Royal University Hospital: Saskatoon, Sask.
Colorado Neurological Institute: Denver, Colo.
St. Michael’s Hospital: Toronto, Ont.
UPMC Medical Centre: Pittsburgh, Penn.
Queen Elizabeth II HSC: Halifax, N.S.
Toronto Western Hospital: Toronto, Ont.
University of Alberta Hospital: Edmonton, Alta.
Chattanooga Center for Neurologic Research: Chattanooga, Tenn.
CHUM-Hospital Notre-Dame: Montreal, Que.
MUSC-Medical University of South Carolina: Charleston, S.C.
Sunnybrook Health Centre: Toronto, Ont.
The Ottawa Hospital: Ottawa, Ont.
London Health Sciences Centre: London, Ont.
McGill University (MNI): Montreal, Que.
Beaumont Hospital: Dublin, Ireland
Abington Memorial Hospital: Abington, Penn.
Royal Victoria Hospital: Belfast, N. Ireland
Yonsei University (Severance Hospital): Seoul, South Korea
Samsung Medical Centre: Seoul, South Korea
Keimyung University (Dongsan Medical Centre): Daegu, South Korea
Temple University: Philadelphia, Penn.

Learn more about ESCAPE at: (website live on Feb 11 at 12 pm ET)


Media contacts:

Hazel Harding
Communications Advisor
The Ottawa Hospital
T: 613-737-8460

Marta Cyperling
Media Relations Manager, Cumming School of Medicine
University of Calgary
T: 403.210.3835