Stroke patients who reach the hospital within three hours of experiencing symptoms can be treated with a drug that breaks up blood clots and restores blood flow, potentially sparing precious brain tissue from damage. Current guidelines state that the drug, called tissue plasminogen activator, or tPA, must be given within three hours. A study published today in the journal Stroke, however, suggests that the three-hour window may be too narrow.
Researchers at Stanford University and colleagues in Germany and Belgium have shown that treatment can help patients up to 4.5 hours after the first symptoms appear. The study is published online in the journal Stroke. The researchers combined data from four large clinical trials on tPA. Among a total of 1,622 patients who arrived at the hospital between three and 4.5 hours, treatment with tPA improved their odds of a favorable outcome by 31%. A favorable outcome was defined as returning to normal or having only minimal residual symptoms, such as some numbness.
With 750,000 Americans suffering a stroke each year, expanding the recommendation for tPA for up to 4.5 hours could help a large number of people, said the lead author of the study, Maarten Lansberg, an assistant professor of neurology and neurological sciences at Stanford.
"We've known that this treatment works for ischemic stroke since 1995," Lansberg said in a news release. "But in the United States, only about 3% of stroke patients end up getting treated. Most of them are ineligible because they come to the hospital after the three-hour time window."
The Food and Drug Administration has approved tPA for use in the first three hours after stroke symptoms begin. But doctors can use the medication after that three-hour window as an "off-label" indication.
For more information on the symptoms of stroke, treatment of stroke as an emergency and other information, see this Web page from the National Institute of Neurological Disorders and Stroke.
-- Shari Roan