In 2012, three Canadian researchers launched a study that would revolutionize how surgeons around the world treat major ischemic stroke.
The ESCAPE trial delivered the biggest advance in stroke care since clot-busting drugs, showing endovascular thrombectomy (EVT) could halve deaths from the most severe strokes — caused by large clots blocking major brain arteries — while dramatically reducing disability.
While a trial in the Netherlands presented positive data in November 2014, the ESCAPE trial provided critical evidence to confirm the findings — and change the course of stroke care.
Drs. Michael Hill, Andrew Demchuk and Mayank Goyal published their results in The New England Journal of Medicine in February 2015 and presented them simultaneously at the International Stroke Conference in the United States.
Further confirmation followed quickly. “By June of 2015, there were five positive EVT trials worldwide,” Dr. Demchuk recalls. “It was clear proof that we had to make this the standard of care for the largest strokes.”
A pioneering approach to major strokes
ESCAPE — short for Endovascular treatment for Small Core and Anterior circulation Proximal occlusion with Emphasis on minimizing CT to recanalization times — studied 316 patients to test whether faster, more targeted clot removal could save lives and limit disability.
Using advanced imaging and specialized tools, doctors guided a thin catheter through an artery in the groin to the brain, where a retrievable device called a stentriever removed the clot and restored blood flow.
Even before ESCAPE began, Dr. Goyal had started using newer clot‑removal devices off label and was seeing promising results. All three researchers were also involved in IMS3, an earlier trial that was unsuccessful but instructive. “I immediately saw the problems and the solutions for us to move forward,” says Dr. Goyal.
Those insights shaped ESCAPE’s design, testing EVT within a model of care that combined three critical elements:
- rapid imaging to identify eligible patients
- x‑ray guidance to navigate the stentriever to the blockage
- faster treatment through coordinated workflows and specialized surgeon training
A Canadian-led collaboration
ESCAPE was conducted at 22 sites across Canada, the United States, Ireland and South Korea. Nearly a third of patients were enrolled in Calgary and Edmonton. “It was a real Alberta story,” says Dr. Demchuk.
Lead researcher Dr. Hill calls himself and his principal collaborators “the three musketeers.” Hill, a seasoned stroke trialist, set rigorous standards for methodology; Goyal, a neuroradiologist, drove technical innovation and fundraising; and Demchuk, a stroke neurologist, anchored the collaboration. Their trust and shared purpose were central to the trial’s success.
An ischemic stroke is a really bad thing to happen to someone. Anything we could do to lessen the burden was important.
A trial halted by its own success
“There were several exciting moments,” recalls Dr. Goyal — “from conceiving the basic trial design over breakfast on the back of a napkin, to getting the funding, enrolling the first patient and — of course — finishing the trial.”
That finish came sooner than expected. In the fall of 2014, an independent Data Safety Monitoring Committee reviewed interim results. Death rates dropped 50% among patients receiving EVT. Positive outcomes in areas including mobility, speech and cognition rose to 55%, from 30%.
On the strength of that evidence, the committee recommended stopping the trial and fast‑tracking EVT into frontline stroke care.
Time is brain
ESCAPE reinforced a core truth in stroke care: every minute counts. The phrase ‘time is brain’ reflects the reality that delays in treatment lead to irreversible brain injury.
Recognizing stroke symptoms and acting fast can save a life. FAST is an easy way to remember the warning signs:
Face — is it drooping?
Arms — can you raise both?
Speech — is it slurred or jumbled?
Time — to call 9-1-1 or your local emergency number right away.
Changing best practices
After the ESCAPE results were published, Heart & Stroke incorporated EVT into the Canadian Stroke Best Practice Guidelines, making Canada one of the first countries to adopt the treatment system‑wide.
Today, EVT is performed at 27 specially equipped hospitals across Canada and in about 100 countries, with an estimated 400,000 procedures done each year.
It is great to see EVT being implemented all across the world and to see changes in guidelines worldwide.
A launchpad for progress
Since ESCAPE, the Calgary Stroke Program has continued to advance thrombectomy research, testing its role in new patient groups and clinical scenarios.
“We recently completed a trial called ESCAPE MeVO for smaller vessels,” says Dr. Goyal. “The trial was not positive but helped us and others to move forward.”
Other studies have expanded EVT’s reach — showing benefits for later treatment windows and more extensive brain injury — alongside major gains in imaging, devices and techniques.
ESCAPE also elevated Calgary on the global stage. “It helped to solidify our reputation at the Calgary Stroke Program,” Dr. Goyal says. “It allowed us to attract talent from all over the world and collaborate across the globe.”
One of ESCAPE’s most profound impacts has been how stroke is diagnosed. “Because we have this thrombectomy treatment now, it's really forced the field to look at the pipes,” Dr. Demchuk says. Proving the need to identify large clots led to widespread adoption of CT angiography.
The team’s work continues in urgent areas. “Bleeding strokes desperately need treatment,” says Dr. Demchuk, pointing to international collaborations that have already produced “very intriguing data.”
Despite this progress, system gaps remain. “One of the challenges in Canada is what I call door‑in, door‑out times,” says Dr. Demchuk — delays at hospitals that cannot offer thrombectomy before patients reach specialized centres.” Accelerating transfer times is a priority.
ESCAPE’s legacy is still unfolding — not only in research, but in how stroke care is delivered, so that more people can benefit from the transformative treatment it pioneered.
Funding breakthroughs
Thanks to donors and supporters, Heart & Stroke provided funding through Dr. Hill’s Heart and Stroke Foundation/Hotchkiss Brain Institute Professorship in Stroke Research and Dr. Demchuk’s Heart and Stroke Foundation Chair in Stroke Research. Other funders included Alberta Innovates-Health Solutions and Medtronic (who provided most of the funding), along with donors to the Hotchkiss Brain Institute Stroke Team and the Calgary Stroke Program.
