The global burden of stroke is immense and growing, a new report suggests, making it one of the biggest public-health problems worldwide in terms of both death and disability. Experts have called for a three-pronged approach encompassing prevention, acute treatment and recovery/rehabilitation to stem the tide. Yet despite billions of dollars invested in research over the last few decades, little progress has been made in preventing or treating stroke. Perhaps nowhere is this failure clearer than in the emergent treatment of stroke.
The clot-busting drug known as tPA (tissue plasminogen factor) was approved in the U.S. in 1996, and remains the only treatment for acute ischemic stroke (strokes caused by a blood clot or narrowing of a blood vessel–see image). tPA has been shown to be highly effective in sparing brain damage and reducing disability when used appropriately in the right group of patients, but the drug is widely underused.
That situation is slowly improving–a study published in 2013 found nearly twice as many stroke patients received tPA in 2011 than in 2003. Still, only about 7 percent of stroke patients receive the drug. A growing chorus of experts are saying that’s because of outdated guidelines that are too restrictive in delineating which patients are eligible for tPA therapy.
When the U.S. FDA approved tPA, it stipulated that the drug should be used within three hours of the onset of stroke. In 2009, an American Heart Association scientific advisory committee cautiously expanded the treatment period to 4.5 hours for some patients, based on a large European study that had already prompted a change in European stroke guidelines.
“My own bias is that the whole thing was a mess,” says Dana Alliance for Brain Initiatives member Louis R. Caplan, M.D., a professor of neurology at Harvard Medical School and senior neurologist at Beth Israel Deaconess Medical Center. The three-hour window and the restrictive eligibility requirements were based on studies that were planned and executed in the late 1980’s and early 1990’s that used “very old technology,” he says. The studies specifically excluded anyone whose stroke had occurred more than three hours prior or in whom the time of stroke onset could not be determined.
“The idea that you turn from a queen to a pumpkin when the clock strikes three is ridiculous,” asserts Caplan, who is the editor of the most widely used stroke textbook for neurologists and co-author of Striking Back at Stroke: A Doctor-Patient Journal. He says the guidelines are meant for emergency physicians with little or no experience treating stroke, whereas the emphasis should be on getting patients to a comprehensive stroke center equipped with the latest technology and qualified personnel.
“You work out with each patient what’s best for them,” Caplan says. “With some patients, you don’t stop because of the clock.”
Brenda Patoine is a freelance science writer who has been covering neuroscience for more than 20 years.