Jennifer Campbell

The minute your brain strokes out, brain cells start dying very quickly. In fact, 1.9 million brain cells die every minute during an acute stroke, which is usually caused by a blocked artery in the brain.

“The faster we treat someone having a stroke, the better the outcome,” says neurologist Dr. Michael Hill, director of the Stroke Unit at the Foothills Hospital. “It’s important that people learn to recognize the symptoms of a stroke and react immediately by calling 911.”

For every hour left untreated, 120 million brain cells are destroyed along with 830 billion synapses and 714 kilometres of myelinated fibres — the stuff that keeps your brain, the body’s control and communication centre, working effectively. With this kind of rapid and progressive brain damage, it’s not surprising that stroke is one of the leading causes of serious acquired disability in Canadian adults.

“With over 50,000 Canadians diagnosed with stroke every year, the economic and social impact of stroke is enormous,” says Hill. The economic burden to Canada’s economy is nearly $3 billion a year; the emotional and physical trauma to Canadian families immeasurable. Over 50 per cent of stroke victims are disabled for life, with 10 per cent of this group requiring long-term care.

Yet despite its tragic impact, research dollars for new and improved treatments for stroke are far behind. “Stroke has a relatively larger impact on society compared to the funding it receives,” says Hill. “Currently, Canadian funding allocated to heart disease research is eight times more than for stroke [research].”

“Few treatments have been developed to either prevent strokes or reduce disability,” says neurologist Dr. Andrew Demchuk, chair of the board of directors for the Heart and Stroke Foundation of Alberta, NWT and Nunavut (HSFA) and director of the Calgary Stroke Program.

“Stroke is a challenging disease because it has many underlying causes,” says Demchuk. “Strokes are caused by a blood clot or a ruptured vessel in the brain which can present itself in various shapes, sizes and locations.”

Clearly, a number of variables influence the course of action when treating a stroke patient. Fortunately, Alberta is home to a group of world-leading stroke neurologists, with seven of these experts working at Calgary’s Foothills Hospital.

Further to providing treatment to stroke patients, many of the clinical neurologists are involved in research, investigating and developing new and improved technologies and methods for the prevention, diagnosis, treatment and rehabilitation of stroke.

Alberta stroke researchers receive funding from provincial, federal and international funding agencies, as well as from the HSFA. The Foundation provides $5 million of funding annually to Alberta researchers for heart and stroke research. Hill is also holder of one of two professorships in stroke research funded by the HSFA.

Further to treating patients on a daily basis, both Hill and Demchuk are involved in numerous international and local research projects. For instance, Hill is currently the lead medical investigator in collaboration with Vernalis Group, a bio-pharmaceutical company based in England. They are developing a new clot-busting drug for individuals experiencing an ischemic stroke, which is a stroke caused by a blood clot in the brain.

“When the first clot-busting drug came out in the early 1990s, it revolutionized ischemic stroke treatment,” says Hill, “But tPA only works in 30 to 40 per cent of stroke cases — that’s why we need to develop alternative, better drug treatments.”

Injected intravenously within the first three hours of the onset of a stroke, the clot-busting drug flows through the blood stream, breaks down the blood-clot and re-establishes blood flow — essentially reversing the effects of stroke. However, not all stroke patients are good candidates for tPA and some clots are just too big for tPA to eat its way through them effectively.

Given that no other proven drug can do what tPA is designed to do, researchers are exploring alternative delivery systems of the drug. For instance, Demchuk is collaborating with the University of Cincinnati on the Interventional Management of Stroke (IMS) study, which received $20 million US from the National Institutes of Health, an American granting agency.

The IMS study will enrol 900 patients in over 40 stroke centres across North America. Calgary’s role in the study is to examine the importance of CT scan findings to select the best candidates for alternative methods of drug delivery.

“Instead of injecting the drug intravenously, we are injecting tPA directly on-site to where the clot is located by using a catheter,” explains Demchuk. “And in some cases, patients have the clot removed through a suction device attached to the catheter.” Researchers hope that mechanically delivering tPA directly to the clot will increase its efficacy.

Further to its international research collaborations, Foothills Hospital has gained world recognition for its brain imaging expertise. “With the onset of brain imaging technology, we now have an incredible window of opportunity to identify patients that are at risk of having a disabling stroke,” says Demchuk.

Through a variety of brain imaging techniques — including transcranial ultrasound, computerized tomography scanning (CT) and magnetic resonance imaging (MRI) — Demchuk is investigating how to best detect individuals vulnerable to having a second stroke.

Up to 10 to 20 per cent of individuals that experience a TIA (transient ischemic attack), also known as a mini-stroke, are at risk of having a second stroke within days of their first event. Furthermore, repeat strokes are usually more devastating and disabling than the first. By using advanced imaging techniques on TIA patients during emergency stroke care, experts can detect and potentially treat the area in the brain vulnerable to a second attack.

“The biggest problem stopping us from finding better treatments for stroke is funding,” says Demchuk. “With more funding we could establish beneficial treatments for the disease so much faster,” he says, “and as a result save numerous lives and greatly reduce the disabling effects of stroke.”

Warning Signs of Stroke

The warning signs of stroke are the brain’s way of telling you that it is under attack. Warning signs will vary from one person to another as the expressed symptoms reflect the part of the brain that is being affected by the stroke.

Recognizing the warning signs is key to surviving a stroke and reducing its life-long disabling. If you, or someone you know, experience one or more of the following symptoms, call 911 immediately.

• Weakness — sudden loss of strength and/or sudden numbness in the face, arms or legs, even if temporary

• Trouble speaking — sudden difficulty speaking or understanding and/or sudden confusion, even if temporary

• Vision problems — sudden trouble and/or loss of vision, even if temporary

• Headache — sudden severe or unusual headache

• Dizziness — sudden loss of balance, especially combined with any of the above signs

For more information about stroke go to www.heartandstroke.ca.