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The 'clot-busting drug' tPA can help many victims of ischemic stroke improve their chances for recovery, but only when given soon after the stroke. A stroke expert says we need an improved delivery system for tPA and other stroke treatments.

For victims of stroke, every second counts. In the most common form of stroke, called ischemic stroke, a clot blocks normal blood flow to the brain, resulting in the death of cells that control movement, speech and other functions. Unless treatment is administered within soon after the stroke occurs, these devastating effects can result in permanent disability.

Larry Goldstein, M.D., director of the Duke Stroke Center, says a medication called tPA, or tissue plasminogen activator, can greatly improve chances for recovery from stroke, but only if it's administered within a narrow window of time after symptoms appear. "The Food and Drug Administration has approved tPA for use within three hours of the onset of symptoms of ischemic stroke," he says. "So our time to be able to treat is very, very short."

TPA, popularly known as the 'clot-busting drug,' has been administered as part of medical treatments for almost a decade. It was first given for heart attacks and has also been widely used for clots elsewhere in the body.

The drug is most commonly administered intravenously. It can also be given through a catheter inserted into an artery that has a clot in it.

"The purpose of using TPA is to dissolve a blood clot that's closing off a blood vessel leading to the brain," explains Goldstein. "We have only a short amount of time after the symptoms begin to be able to use a medicine like tPA to restore blood flow to the brain. With a stroke, time lost is brain lost."

Studies have shown that patients who have had an ischemic stroke who received tPA within the approved window of time for treatment had a far better rate of recovery and fewer disabilities as a result of the stroke than patients who did not receive the medication.

"The outcomes improvement has been shown for the randomized controlled clinical trials that have been performed by the National Institutes of Health, as well as through other studies done elsewhere," Goldstein notes.

He cautions that not all victims of stroke can benefit from this treatment. TPA can be life-threatening if given to patients who have the other main type of stroke, called hemorrhagic. In this form of stroke, which accounts for 10 to 15 percent of strokes each year in the U.S., blood vessels in or near the brain burst.

"It has to be given to the exact right patient in the right way," he says. "Right now in the United States, only about three percent of stroke patients receive tPA.

"We're looking for ways to try and extend the treatment window. We're also working towards putting systems into place, both at the state level and nationally, to improve the chances of delivering this therapy to appropriate patients as well as other therapies for acute stroke treatment, not just tPA."

Goldstein adds that even with improved access to tPA and other promising treatments, the best thing to do is to make healthy lifestyle changes to prevent strokes from occurring in the first place.

"The best way to treat a stroke is never to have one to begin with. The general population needs to understand what the risk factors and warning signs are for stroke, to understand that stroke can be treated, and that stroke can be prevented."