THURSDAY, Feb. 18, 2016 (HealthDay News) -- In what one expert called a "counterintuitive" finding, research suggests that the powerful clot-busting drug known as tPA might help patients suffering a hemorrhagic ("bleeding") stroke.
According to the American Stroke Association, only about 15 percent of strokes are caused by runaway bleeding in the brain; the other 85 percent are caused by a clot.
And while it makes sense to use the clot-busting tissue plasminogen activator (tPA) to break up a brain clot, it would seem counterproductive to use the same drug in the case of a bleeding stroke.
However, two new studies to be presented Thursday at the stroke association's annual meeting in Los Angeles suggest that tPA may, indeed, have a role to play in the treatment of a bleeding stroke. Both studies were funded by the U.S. National Institutes of Neurological Disorders and Stroke.
One study involved 500 patients suffering from hemorrhagic stroke who were treated at 73 hospitals worldwide. Researchers led by Dr. Daniel Hanley, of Johns Hopkins University in Baltimore, found that directing tPA at the brain's ventricles -- fluid-filled cavities -- cut the death rate from bleeding stroke by 10 percent, without increasing the number of patients who were severely disabled.
The doctors explained that tPA is used to clear the brain's ventricles of blood that has pooled there as a result of the hemorrhagic stroke.
The technique appears to have a good safety profile, with similar or even lower rates of brain infections or other serious side effects compared to standard treatment, Hanley's team reported.
A second study was led by Dr. Issam Awad of the University of Chicago. His team looked at tPA use in the treatment of intraventricular (within the ventricles) hemorrhagic stroke. Almost 500 patients with this type of stroke received either tPA or a saline solution.
While patients with smaller amounts of pooled blood did not seem to derive a benefit from the treatment, the therapy did seem to help those whose ventricles contained larger amounts of blood, Awad's team found.
That "high-bleed" group had almost twice the likelihood of a good functional outcome after their stroke compared to those who didn't get the tPA, the researchers reported. And with multiple doses of tPA, even more of the bleed was removed from the brain, the Chicago team said.
According to a stroke association news release, Awad's team believes the findings "could change neurosurgical techniques and patient care" in the treatment of hemorrhagic stroke.
One expert agreed that the results of both studies are unexpected but potentially valuable.
"Contrary to belief, infusion of clot-buster drugs into the brain improved outcomes in patients with a brain bleed -- this is counterintuitive, as one would not think that infusing a clot-buster drug would be appropriate and safe," said Dr. Paul Wright, chair of neurology at North Shore University Hospital in Manhasset, N.Y.
However, the new research suggests the treatment could be warranted, he said, since hemorrhagic strokes are particularly deadly.
The research "showed that when 90 percent of the blood cleared [with tPA], the odds of good functional recovery doubled," said Wright, who is also chief of neurology at Long Island Jewish Medical Center in New Hyde Park, N.Y.
"Until now, medical management for hemorrhagic stroke was extremely limited," he noted. But the new research "solidifies a treatment protocol that enables us to provide better hope for functional recovery in a critically ill and usually fatal condition."
The two studies have not yet been published in a peer-reviewed journal, however, and experts note that findings presented at medical meetings are typically considered preliminary until published in a peer-reviewed journal.
Find out more about the signs, symptoms and treatment of hemorrhagic stroke at the U.S. National Library of Medicine.