February 20, 2015
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 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.
London Health Sciences Centre is one of 22 sites worldwide participating in the trial. Neurologist Dr. Jennifer Mandzia is Co-Principal Investigator at the London site and a researcher at Lawson Health Research Institute.
“This is a potential game changer in the field of acute stroke. Patients with moderate to severe stroke and a proximal artery occlusion (blockage) in the brain, both young and old, have a treatment that has shown to improve functional outcome and reduces risk of death compared to standard of care. Clot retrieval needs to be done quickly in the appropriate patients based on imaging selection. This is very exciting for our field and our patients.”
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 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.
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. 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.