Late Stroke Treatment Still Has Benefits
tPA Works Best Soon After Stroke, but Late Treatment Better Than None
Sept. 24, 2008 - The brain clot-busting drug tPA works better the sooner it's given after stroke, but now a new study shows the treatment can help even if given up to 4.5 hours later.
During a stroke, a clot blocks the flow of blood to parts of the brain. It doesn't take long for these parts of the brain to start dying. The clot-dissolving drug tPA (tissue plasminogen activator) restores blood flow to the brain, but the drug must be given soon after a stroke to save brain tissue.
A major U.S. clinical trial in 1995 showed that tPA can help patients for up to three hours after a stroke. Can it work for patients who are treated even later?
European researchers, led by Werner Hacke, MD, of Germany's Heidelberg University, now find that tPA can still help patients up to four and a half hours after a stroke. And this benefit is achieved without an increased risk of destructive bleeding in the brain as compared to receiving tPA within the traditional three-hour window.
However, these findings should not be interpreted to mean that delaying treatment is prudent. Every minute that goes by after a stroke means the death of more brain cells. It's urgent for patients who suffer a stroke to get to a hospital where neurologists can administer tPA.
Patrick Lyden, MD, of the University of California, San Diego, was one of the leaders of the landmark U.S. tPA study. Lyden was fond of reminding medical students of the three-hour window for tPA treatment and then asking them how long they had to treat a patient who suffered a stroke 30 minutes ago.
"The correct answer is one minute, not two and a half hours, and the [Hacke] study does not now justify an answer of four hours," Lyden writes in an editorial accompanying the Hacke report in the Sept. 25 issue of The New England Journal of Medicine.
Hacke and colleagues fully agree. "Having more time does not mean we should be allowed to take more time," they note.
Lyden notes that only four out of every 100 stroke patients receive tPA treatment. This, he suggests, means the health care system in general, and neurologists in particular, are failing stroke patients.
He calls for stronger efforts to get patients to stroke centers more rapidly -- and for stroke patients to get tPA injections very soon after they arrive.
"The potential for reversing the disabling side effects of stroke declines with every passing minute," Lyden says in a news release. "Our focus must remain on the door-to-needle time."