Earlier this year, an advisory committee of the American Stroke Association/American Heart Association issued a recommendation that the window of time for tissue plasminogen activator (tPA) therapy be extended.
The new analysis shows that the medication, which is given intravenously, can safely be used to treat strokes 4.5 hours after symptoms begin. Until this year, tPA had to be given within three hours of symptom onset.
As Jefferson Vascular Neurologist Carissa Pineda, MD, explains, tPA is the only FDA-approved drug for treating the 80 percent of strokes caused by ischemic clots. (The other major type – hemorrhagic stroke – is caused by ruptured blood vessels in the brain. Hemorrhagic stroke cannot be treated with tPA and has a much higher mortality rate than ischemic stroke.)
“tPA can be thought of as a ‘clot buster,’” Dr. Pineda notes. “Once it reaches the clot, it bursts it – limiting the areas of the brain that would have been affected.”
But as Dr. Pineda notes, the original guidelines required the clot-busting drug to be administered within three hours of the onset of symptoms. Even in top-performing hospitals, less than 5 percent of stroke patients are treated in that timeframe.
The new guideline – based on analysis of clinical studies – enables emergency-room physicians and stroke specialists to give tPA up to 4.5 hours after the onset of symptoms.