Use of Clot Busting Drugs for Stroke Expanded
Treating patients with stroke using clot-busting drugs provides better outcomes when the drugs are delivered sooner than later. However, the use of clot busting drugs more than three hours after a stroke has occurred has not been established as a therapeutic norm. Results of a new study shows that the use of clot busting drugs for stroke should be expanded beyond three hours, suggesting that guidelines for immediate treatment of stroke may need to be altered.
Maarten Lansberg, MD, PhD, assistant professor of neurology and neurological sciences at Stanford, along with colleagues from Belgium and Germany, found that clot-busting treatment for stroke can provide benefits when given up to four and a half hours after the onset of stroke symptoms. Clot busting medication, known as tPA (tissue plasminogen activator), can open up arteries and restore blood flow even after the three-hour window. A large number of patients arrive in the emergency room more than three hours after experiencing stroke symptoms, leaving them ineligible for the life-saving treatment.
Dr. Lansberg explains, "We've known that this treatment works for ischemic stroke since 1995. But in the United States, only about 3 percent of stroke patients end up getting treated. Most of them are ineligible because they come to the hospital after the three-hour time window." Studies have been conflicting, and no conclusions have been drawn, leading physicians to follow the three-hour rule of administering tPA to stroke patients.
The current study results come about as the result of examining data from the four major stroke studies measuring the effect of tPA for clot busting. The researcher found that among 1622 patients who came to the emergency room between 3 and 4.5 hours after stroke symptoms, outcomes improved by thirty-one percent.
"A favorable outcome means that patients are either completely back to normal or they have minimal symptoms, like some numbness or a slight facial droop, but they can do everything in their normal life that they were able to do before the stroke happened," says Dr. Lansberg.
Dr. Lansberg led a similar study, looking at six trials, that also showed clot-busting drugs provided benefit when given up to four and a half hours after stroke symptoms occur. He says, "Although this is not as good as treatment at an earlier time, it is still a highly significant benefit for patients treated in this group."
The use of tPA for treatment of stroke, more than three hours after the first symptom is not FDA approved. The new data allows physicians to present the option of receiving clot-busting medication for stroke, expanding its use up to four and a half hours, once the risk and benefits are explained to the patient. Time is still of the essence, say the study authors – Dr. Lansberg emphasizes 'Time is brain' still holds true."