Texas Medical Center News


Vol. 20, No. 2		February 1, 1998

Stroke: Minutes Can Make A Difference

by KRISTINA VAN ARSDEL
Texas Medical Center News

"More than half of all individuals cannot name a single symptom of stroke," says Dr. David Chiu, director of the Baylor/Methodist Stroke Center.

Yet, stroke is the third leading cause of death and the leading cause of disability in the United States. Knowing the symptoms and responding to them immediately can make a difference in what treatment options are available.

"For all acute stroke therapies, minutes count. Time is brain," Dr. Chiu says. "The greatest difference we can make is early on."

The American Heart Association (AHA) refers to stroke as "brain attack," which describes the immediacy of the disease. According to the AHA, the warning signs of a brain attack include:

Sudden weakness or numbness of the face, arm or leg on one side of the body.
Sudden dimness or loss of vision, particularly in one eye.
Loss of speech or trouble talking or understanding speech.

Sudden, severe headaches with no known or apparent cause.

Sudden, severe headaches, says Dr. Chiu, are common with hemorrhagic strokes, a category of stroke characterized by a ruptured blood vessel resulting in bleeding in or around the brain. Hemorrhagic strokes account for approximately 15 percent of all strokes.

Unexplained dizziness, unsteadiness or sudden falls, especially along with any of the previous symptoms.

Sometimes symptoms only last for a brief period of time. A transient ischemic attack (TIA), or small stroke, may have occurred and this could be a signal that a more serious stroke will occur in the future, says Dr. Chiu, assistant professor in the department of neurology at Baylor College of Medicine.

Emergency intervention became an option with the FDA approval of tissue plasminogen activator (TPA). TPA is a clot-dissolving drug used to treat acute ischemic strokes, a type of stroke usually caused by clots obstructing the flow of blood to the brain. Ischemic strokes represent approximately 85 percent of all strokes.

"TPA has been proposed as a treatment for an ischemic stroke of any source. However, some leading stroke experts think it should be restricted to only certain types," says Dr. Jack Alpert, chief of neurology at St. Luke's Episcopal Hospital. The three most common causes of ischemic stroke are: 1) a blood clot that has originated in the heart and traveled to the brain; 2) blockage in a major artery to the brain, such as the carotid artery; and 3) blockage in a small artery in the brain.

TPA can be an effective means for dissolving the blood clot and restoring blood flow to the brain in patients with ischemic stroke if it is given as part of a rigorous protocol under the appropriate conditions, says Dr. Chiu. People who have had recent major surgery, bleeding problems, or extremely high blood pressure are not considered candidates for TPA. TPA is not an option for hemorrhagic strokes.

A major concern with TPA is its very specific window of time.

"Timing is critical. TPA must be given within three hours of the onset of symptoms," says Dr. Chiu. "There is a higher risk of bleeding in the brain beyond three hours.

"The benefits of TPA can be dramatic. When used appropriately, it increases the chance of a good recovery by 50 percent," Dr. Chiu says. "However, the risks are very real. If the proper protocol is not followed, the risks may outweigh the benefits."

Only a very small number of stroke patients are currently receiving TPA.

"We could help a lot of people, but we're losing out on the time window," says Dr. Chiu. "That is by far the most common reason for not being able to give TPA."

Other emergency intervention therapies are currently in the research phases, including a category of drugs called neuroprotective agents.

"The inciting event with ischemic stroke is a blood clot and interruption of blood flow, but that triggers a cascade of biochemical events that lead to the destruction of brain tissue," says Dr. Chiu. "Neuroprotective agents, if given within a six hour time window, can theoretically modify some of these steps to prevent them from occurring and decrease the effects of stroke."

Are You At Risk For Stroke?

"Stroke is one of the most preventable major diseases," says Dr. Chiu. The risk factors for stroke include:

A family history of stroke.
High blood pressure.
Diabetes.
Smoking and exposure to smoke. "Everyone thinks of smoking and cancer in one breath," says Dr. Alpert. "As a neurologist, I think of smoking and stroke, carotid disease, and premature death and disability from smoking as it affects the cerebral circulation. If we could cut down on smoking, we could eliminate a large percentage of strokes."
Heart disease. "Heart disease and stroke are very closely associated," says Dr. Alpert. "If you take patients with carotid disease and no heart symptoms, you find they often have co-existing unrecognized heart disease."
High cholesterol. "Recent studies have shown that treating and lowering high cholesterol can reduce the risk of stroke," says Dr. Chiu.
TIA or a small stroke.

"Treatment of risk factors can lead to a decreased risk of stroke," says Dr. Chiu. "Diet and exercise are important as well."

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