Clot-Busting Stroke Drug's Benefit Reaffirmed
Patients Need Treatment Within 3 Hours of Stroke Symptoms
Sept. 2, 2004 -- Immediate medical attention can make all the difference to someone showing signs of a stroke.
Researchers have reaffirmed the value of a clot-busting drug called tPA (tissue plasminogen activator) that can significantly reduce the effects of stroke. But time is crucial with tPA; the drug should be given within three hours of the first signs of stroke.
Stroke symptoms include:
- Weakness or numbness of the face, arm, or leg on one side of the body
- Loss of vision or dimming (like a curtain falling) in one or both eyes
- Loss of speech, difficulty talking or understanding what others are saying
- Sudden, severe headache with no known cause
- Loss of balance or unstable walking, usually combined with another symptom
Some of these signs can be subtle; stroke is not always a dramatic event. If any of the above symptoms come on suddenly, that's a good sign that it may be a stroke. In addition, if someone wakes up with these symptoms and they don't go away right away, that's another sign that you need to get medical attention right away.
So if you or someone you know ever notice these symptoms -- to any degree -- call 911 immediately. Let the experts figure out what's going on; don't just ignore it or wait for it to pass.
Stroke occurs when blood flow to an area of the brain is cut off. Without getting oxygen and nutrients, brain cells die. Permanent brain damage can occur if a stroke is not caught early.
In 1996, the FDA approved tPA for treating ischemic stroke, the most common type of stroke. In ischemic stroke, blood clots block blood flow to the brain's cells.
The drug should be used within three hours of the start of symptoms. That's why quick medical attention is so important. There is not enough proof that using clot busters more than three hours after a stroke is helpful. After that point, the risks of bleeding in the brain may outweigh the potential benefits.
Stroke's effects, which can include permanent disability, can be significantly reduced by tPA, a clot-dissolving drug given through an intravenous line, according to the American Heart Association.
A Second Look at tPA
Some experts had questioned tPA's safety and effectiveness. In particular, they were concerned that it might lead to bleeding in the brain. Since tPA works by essentially thinning the blood -- thus dissolving the clot -- there is a risk of bleeding in the brain.
A committee of researchers poured back over data from the trial, which was based on 624 patients.
"A clinically important and statistically significant benefit of tPA therapy" was reported by the scientists, who were led by Timothy John Ingall, MD, PhD, associate neurology professor at the Mayo Clinic in Scottsdale, Ariz. Patients that received tPA had fewer effects from their stroke three months later.
The benefit was noted despite an increased frequency of bleeding in the brain in tPA-treated patients, write the researchers.
Timing Is Critical
Again, quick treatment is urgent. The researchers emphasized the crucial three-hour window for tPA use.
Their review is published in Stroke: The Journal of the American Heart Association.