BALTIMORE, May 16 (UPI) -- A multicountry study of stroke patients found survivability was boosted by prescribing the clot-busting tissue plasminogen activator, a U.S. researcher says.

Study leader Dr. Daniel Hanley of The Johns Hopkins University School of Medicine says tissue plasminogen activator, also known as tPA, can worsen hemorrhaging. However, the researchers in Britain, Canada and German said they were able to use very low doses to dissolve the trapped blood out of the brain in an average of three to four days with minimal additional bleeding.

"We've gone from what's usually an 80 percent death rate in patients with this condition to an 80 percent survival rate," Hanley said in a statement.

The researchers recruited 52 recently diagnosed intracerebral hemorrhage patients in 20 hospitals. Each had a catheter inside the brain to release the trapped blood -- the usual treatment.

Using the same catheter to inject tPA, researchers put each patient on one of three regimens. Progress was tracked with daily CT scans.

Those on 1 milligram of tPA every 8 hours dissolved the clots about a day faster than the other regimens.

After one month, 10 percent of the patients in the study recovered enough to return to their jobs.

The findings were reported at the European Stroke Conference in Nice, France.