After 4.5 hours, odds for good recovery decline sharply and risk of dying increases, study finds
THURSDAY, May 13 (HealthDay News) -- Patients who get the clot-busting drug alteplase (tPA) within 4.5 hours of having a stroke fare better than patients who are given the drug later, Scottish doctors report.
It has been known that treating a stroke earlier is better than later, but this study shows for the first time that there is significant harm done with starting tPA after 4.5 hours, the researchers noted.
"The benefit of giving this treatment for stroke continues if we start it as late as 4.5 hours," said lead researcher Dr. Kennedy R. Lees, from the University Department of Medicine and Therapeutics of the Gardiner Institute at the Western Infirmary in Glasgow.
"There is no net benefit to patients if you start the treatment after 4.5 hours. But if you start treatment after 4.5 hours, you will have more patients who die," he added.
"Starting at an hour is much better than starting at two hours, and that's better than three hours, and that's better than 4.5 hours," Lees explained.
The benefit derived from early tPA treatment is a long-term benefit, Lees pointed out.
"It's a benefit that we can measure three months later," he said. "So, what we are getting is long-term improved function. They are more likely to have no symptoms and more likely, if they do have symptoms, to be able to do things for themselves, or need less help. A whole range of disability is reduced, by just starting tPA a few minutes earlier."
The report is published in the May 15 issue of The Lancet.
For the study, the research team collected data on 3,670 patients in eight trials that investigated how the benefits and risks of tPA changed based on the time the drug was given after the onset of a stroke.
The investigators found that when tPA was given within 4.5 hours, the chances
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