Calgary University. Canada: 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 the study were published in Wednesday’s online edition of the New England Journal of Medicine.
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 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.
Procedure uses image-guided care and retrievable stent
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.
Advance credited to quick response, brain and blood vessel imaging
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, first
author on the publication, and lead interventional neuroradiologist on
the ESCAPE trial. He performs the procedure at Foothills Medical Centre.
“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 centre Randomized Clinical
trial of Endovascular treatment for Acute ischemic stroke in the
Netherlands), was published in December 2014.
McCauley: 'Potential to improve lives of 15 million people worldwide each year'
“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.”
“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.”
Study involved 22 sites around the world
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.
Brain and Mental Health is one of six strategic research themes guiding the University of Calgary towards its Eyes High goals.
Taking part in the study were: Foothills Medical Centre, Calgary;
Royal University Hospital, Saskatoon; Colorado Neurological Institute,
Denver, Colo.; St. Michael's Hospital, Toronto; UPMC Medical Centre,
Pittsburgh, Penn.; Queen Elizabeth II HSC, Halifax; Toronto Western
Hospital, Toronto; University of Alberta Hospital, Edmonton; Chattanooga
Center for Neurologic Research, Chattanooga, Tenn.; CHUM-Hospital
Notre-Dame, Montreal; MUSC-Medical University of South Carolina,
Charleston, S.C.; Sunnybrook Health Centre, Toronto, Ont.; Ottawa
Hospital, Ottawa; London Health Sciences Centre, London, Ont.; McGill
University, 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 Hospital,
Philadelphia, Penn.