Cover Story

1. Stroke

1. Brain imaging following stroke
2. Brain imaging following transient ischemic attack
3. Hemorrhagic stroke
4. A close look at white matter
5. Restoring movement

Features

1. Battles in the bowel
2. Environment and health
3. Activating motor circuits in the spine

In every issue

1. Voices from the community
2. Responding to the reader
3. Cool tools
4. Researchers in the making
5. Following Up

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About the researcher

Dr. Ken Butcher receives support through Alberta Innovates – Health Solutions, funded by the Alberta Heritage Foundation for Medical Research Endowment Fund. He is an assistant professor in the Department of Medicine at the University of Alberta.

Selected publications

Butcher K, Jeerakathil T, Emery D, Dowlatshahi D, Hill M, Sharma M, Buck B, Findlay M, Lee T, Demchuk A. The intracerebral hemorrhage acutely decreasing arterial pressure trial: ICH ADAPT. International Journal of Stroke. 2010. In press.

Hemorrhagic stroke

Although the vast majority of strokes are ischemic, a significant number (10% in Caucasians and up to 30% in Asians and Africans) are caused not by a blockage but by a hemorrhage—bleeding in the brain—that interrupts normal blood flow in the brain and kills brain cells.

There are two main types of hemorrhagic stroke: subarachnoid hemorrhage is uncontrolled bleeding on the surface of the brain in the area between the brain and the skull, and intracerebral hemorrhage occurs when an artery deep within the brain ruptures. Although they can be deadly, there is a well-established treatment for subarachnoid hemorrhages. But there is no treatment for intracerebral hemorrhage, the most common type of hemorrhagic stroke.

"Physicians used to think that, when a blood vessel ruptured deep in the brain, the pressure in the brain would stop the bleeding," says Dr. Ken Butcher, a stroke neurologist and researcher at the University Alberta. "It turns out that, in about 30% of patients, there is significant growth of the hemorrhage over time. The brain is not as good at stopping bleeding as we once thought. This is relevant because patients can come into emergency with a very survivable hemorrhage that grows over the next few hours, and all of a sudden, they are in a coma."

Early in his career, Dr. Butcher began to suspect that certain hemorrhages could expand. While doing postdoctoral work in Australia, he got the opportunity to follow up on this hunch by using MRI to study blood flow in hemorrhagic stroke. "Almost everyone with a hemorrhagic stroke has chronic high blood pressure," explains Dr. Butcher. "So you might think that the obvious treatment would be to lower blood pressure in these patients. But this isn't done routinely. There's a fear that since blood flow is already reduced in the tissue around the blood clot, a further reduction in blood flow from blood-pressure medication could cause an ischemic stroke. Our work in Australia showed that in hemorrhagic stroke patients, the blood flow reduction around the clot is only moderate. It remains unknown, however, if rapid reduction of blood pressure will aggravate this situation and actually cause ischemia."

Dr. Butcher is now running a clinical trial in collaboration with colleagues at the University of Calgary to test the safety of blood pressure reduction in hemorrhagic stroke. People with hemorrhagic stroke are randomly assigned to one of two groups: current standard of care, where blood pressure is treated only if it is very high, and a more aggressive treatment to reduce systolic blood pressure (the top number in a blood pressure reading) to less than 150. Blood flow is then measured in the brain using a special CT scan and compared in the two groups.

The trial is underway now in Edmonton and Calgary, and the team has already enrolled more than two-thirds of the target of 74 patients. Once safety is proven, Dr. Butcher hopes to conduct a large cross-Canada trial to look at clinical outcomes.