A new joint study from the University of Calgary and the University of California Los Angeles has found that the window for treatment of stroke may be longer than previously determined.
The study looked at data from five clinical trials involving 1,287 patients and found that brain damage to stroke victims could still be limited if treatment was performed within seven hours of the onset of stroke. Previous practice had assumed that patients normally had just a six-hour window during which treatment could be effective, and researchers say that the additional hour could be a huge factor in stroke treatment, especially for patients living at a distance from hospitals.
“What’s new for us is the real understanding that we can extend the time window in selected patients to longer times,” says Dr. Michael Hill, neurologist at the Foothills Medical Centre in Calgary and co-author of the study. “That’s really helpful for us in Alberta because we have a huge geographic region to deal with so flying someone from say, High Level down to Edmonton, is still potentially a good idea for treating stroke.”
Stroke is the third leading cause of death in Canada and the leading cause of adult disability, with more than 400,000 Canadians currently living with long-term stroke disability, according to the Heart and Stroke Foundation.
Stroke occurs when blood flow to the brain is cut off by either a rupture of blood vessels or, more commonly, a blockage in an artery carrying blood to the brain. The latter, called ischemic stroke, is treated with a combination of clot-busting drugs together with a procedure called endovascular thrombectomy, involving an intravenous stent to remove the blood clot. The stent procedure, first invented at UCLA, uses a thin mesh tube inserted through an artery which progresses towards the site of the blockage and then surrounds and secures the clot before pulling it out, somewhat similar to a corkscrew pulling a cork out of a bottle.
The study found that outcomes for stroke patients were better – meaning a lower risk of long-term disability – if the thrombectomy was performed in combination with drug therapy rather than drug therapy alone. And while outcomes were better if the procedure occurred during the first two hours after stroke onset, there were nonetheless benefits found in using the procedure up to 7.3 hours after onset.
“It is important for the public to know the critically important relationship between time to treatment and outcome, so they know to activate the 911 system as soon as possible when they detect stroke symptoms in themselves or friends, family and co-workers,” says Dr. Jeffrey Saver, director of the UCLA Comprehensive Stroke Center and lead author of the study.
The warning signs of stroke include a drooping or numbness on one side of the face, weakness or numbness in one of the arms and slurred speech. Health professionals advise to call 911 immediately upon presentation of these symptoms and warn that people should not drive themselves or the person having the stroke to the hospital but they should let an ambulance take them to the nearest facility with a specialized program for care of stroke.
The Heart & Stroke Foundation states that up to 80 per cent of premature heart disease and stroke is preventable through adopting a healthy diet, physical activity and eliminating tobacco and smoking.