Researchers find new therapy benefits stroke patients
Alberta Innovates – Health Solutions funded team hope to change stroke clinical care guidelines
Feb. 11, 2015
Canadian researchers have completed 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 February 11, 2015 online edition of the New England Journal of Medicine (NEJM).
Overall, positive outcomes for patients increased from 30 percent to 55 percent. In many cases, instead of suffering major neurological disabilities, 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 is the most significant and fundamental change in acute ischemic stroke treatment in the last 20 years. These results will impact stroke care around the world,” says Dr. Michael Hill, the senior author of the study, professor in the Cumming School of Medicine’s departments of clinical neurosciences, and radiology and a neurologist with the Calgary Stroke Program of Alberta Health Services (AHS).
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’, tPA 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.
“Key reasons for the success of the trial were, firstly, selecting appropriate patients using novel imaging technology; secondly, better organization and workflow to expedite treatment; and thirdly, use of modern technology to open the blood vessels,” says Dr. Mayank Goyal, professor of radiology and clinical neurosciences at the Cumming School of Medicine, co-principal investigator of the ESCAPE trial and first author on the publication, and lead interventional neuroradiologist on the ESCAPE trial. He performs the procedure at Foothills Medical Centre in Calgary, Alberta. “We believe that with the combined results from this trial and other trials, this will become the standard of care.”
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.
“This breakthrough has the potential to improve the lives of the 15 million people who suffer strokes worldwide each year,” says Ed McCauley, PhD, vice-president (research), University of Calgary. “University of Calgary researchers have been transforming health outcomes for close to 50 years now, and the work of Drs. Michael Hill, Mayank Goyal, and Andrew Demchuk will improve the quality of life for Albertans, Canadians and people around the world.”
“We congratulate the University of Calgary ESCAPE team for their contributions to the development of this life-changing procedure,” says Dr. Cy Frank, President and CEO of AIHS. “We are proud to support members of the team and applaud their collaborative efforts to refine, test, develop and implement an innovation that will improve the health and wellbeing of Albertans and people around the world.”
“This remarkable achievement by the HBI Stroke Team is a shining example of brain research at its very best,” says Samuel Weiss, PhD, HBI Director and leader of the University of Calgary’s Brain and Mental Health strategy. “Our vision of ‘Healthy Brains for Better Lives’ has taken a giant leap forward.”
While research is improving outcomes, doctors still want patients to know the warning signs and symptoms of stroke. “Many stroke treatments work only if administered in a set period of time. Many patients don’t get to the hospital in time. With stroke, when removing the clot with this new treatment, every minute matters,” says Dr. Andrew Demchuk, another ESCAPE co-principal investigator and leader of both the Stroke Program at Foothills Medical Centre and the HBI Stroke Team. “If patients have facial drooping, arm weakness or speech difficulty, they need to call 9-1-1 immediately.”
The study included 22 enrolling 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 Alberta Innovates-Health Solutions, the Heart and Stroke Foundation of Canada, and Medtronic, along with generous donations to the HBI Stroke Team and the Calgary Stroke Program.
In the news
University of Calgary, Sept. 28, 2016: Early treatment leads to less disability following stroke, study finds
Calgary Herald, April 7, 2015: The Great ESCAPE: How Calgary doctors forged a new weapon against stroke
The Globe and Mail, Feb. 11, 2015: New procedure a ‘major breakthrough’ in stroke treatment: Canadian study
Heart and Stroke Foundation, February 11, 2015: Research breakthrough to revolutionize stroke treatment
Read more impact stories about AIHS-funded research into stroke:
A breakthrough in acute stroke treatment: International trial promises to revolutionize stroke care with a new procedure
Taking care of our future: Alberta-based researchers are studying childhood diseases and their risk factors
High school student researches stroke using a robot in the lab
Can technology silence a silent killer?