Study opens door to critical stroke treatment
More stroke victims will now have access to an increasingly effective surgery after the surprising results of an international study, spearheaded by University of Calgary researchers and recently published in the New England Journal of Medicine.
Dr. Michael Kelly, a neurosurgeon and leader of the University of Saskatchewan portion of the study, sat down with The StarPhoenix to explain the issue.
The treatments
Many severe stroke patients receive an intravenous fluid meant to dissolve blood clots in the brain. However, there’s limited blood flow to those vessels, so it’s only effective eight to 20 per cent of the time, and it can only be administered within four hours of a stroke to avoid the risk of a hemorrhage, Kelly noted.
Physical removal of the clot, known as endovascular treatment (ET), has become more promising over the past six years as technology has advanced. In this therapy, Kelly inserts a tube through a stent in a leg artery, then guides it to the blockage in the brain and sucks the whole thing out.
The problem
Kelly has been concerned he lacked the data needed to definitively recommend ET to patients.
“Over the last decade there have been a bunch of techniques tried, a bunch of studies performed, trying to look at (ET’s) usefulness,” Kelly said.
“There’s been mixed success with that, some positive and some negative, but no study as good as the one we’re talking about today.”
The study
Known as ESCAPE, the study tracked 316 patients across 22 centres in Canada, the United States, the United Kingdom, Ireland and South Korea. Canada had 11 participating hospitals and enrolled two thirds of the patients.
Those who fit the criteria for ET and arrived for treatment within 12 hours of their strokes were randomized to standard medical care, including the clot-busting IV, or standard medical care plus ET.
The findings
The study was so successful, researchers ended it early. ET is now established as the global standard of care, Kelly said.
“When I was first involved in the study I sure hoped it would be positive, but I have to say I didn’t expect the results would be as great as they are.”
Patients receiving ET had a one in 10 mortality rate — half the two in 10 rate for patients receiving standard care. More importantly, the survivors were healthier, with about a 25 per cent chance of going home and being independent, Kelly said.
He noted that ET is only meant for the most severe blockages, which can be half a centimetre in diameter, in the main arteries in the brain.
The future
“What this does is it lights a fire under stroke care’s butt,” Kelly said.
Stroke is one of the main killers of Canadians, and the top cause of long term disability, Kelly said. It also affects people in the prime of their lives, not just the elderly.
“If we can create more survivors and more people that do well, that’s a huge impact for society as a whole.”