Milwaukee Journal Sentinel
May 29--For more than a decade, an effective medication to treat stroke has been sitting on the shelves at hospital pharmacies, but only a tiny percentage of people get to the emergency room quick enough to receive it.
Now doctors think they have at least a partial solution to the problem: Extend the time window for treatment from three hours after symptoms start to 4 1/2 hours.
The change, which could have important implications for treating the leading cause of serious disability in the United States, is the result of new research and a scientific advisory published Thursday.
It comes as the population is aging and the incidence of stroke, which occurs about 750,000 times a year in the U.S., is expected only to increase. Doctors continue to be frustrated because the clot-dissolving drug tPA is known to substantially reduce disability, but less than 3% of stroke patients are treated with it, mostly because they fail to get to the hospital within the three-hour treatment window. Also, some hospitals have lagged behind in using the drug.
"We need to get more emergency room physicians and neurologists on board," said the study's lead author, Maarten Lansberg, an assistant professor of neurology at Stanford University School of Medicine. "We also need more community awareness."
The drug tPA was first approved by the Food and Drug Administration in 1996, but the number of people treated with it has not increased substantially.
One big problem is that many people having a stroke wait too long before calling 911 and going to a hospital.
The new research, which analyzed data from four clinical trials, shows that treating them with intravenous tPA as far out as 4 1/2 hours can significantly reduce the risk of disability.
The research, published in the journal Stroke, showed that those treated with tPA between three hours and 4 1/2 hours were 31% more likely to have a favorable outcome, meaning minimal or no disability, than those who were not treated.
Earlier research has showed that 39% of patients treated within three hours with tPA had a favorable outcome, compared with 26% who did not get the drug.
"It will result in more people being treated," Lansberg said.
Some restrictions apply
Just how many more people will be treated is a matter of speculation and is complicated by a number of factors.
The extended window does not apply to people older than 80, those having severe strokes, those with diabetes, those who had an earlier stroke and those taking anti-clotting drugs.
But even if it is only 1% more people who are treated, that's nearly 8,000 additional patients a year in the U.S., said Justin Sattin, an assistant professor of neurology at the University of Wisconsin School of Medicine and Public Health and medical director of UW's stroke program.
"That's a lot of disability saved," he said. "That's a lot of people who won't have to go to a nursing home."
Still, many people having a stroke wait too long before calling 911.
In March, UW, along with Watertown Regional Medical Center, began a groundbreaking telemedicine program to treat people in rural areas with tPA. The program allows stroke specialists at UW Hospital to examine patients at the Watertown hospital via a two-way video camera. They also can see the results of a CT scan of the brain.
Once that is done, they can make a decision on administering tPA in Watertown.
The goal is to develop an even more extensive telemedicine network linking rural and smaller hospitals with certified stroke centers throughout the state.
Time is one of the biggest obstacles in treating stroke with tPA.
It is estimated that for every minute an artery remains closed, 2 million neurons die. And 14 billion synapses, the root-like appendages between brain cells, are lost.
Side effects vs. benefits
Based on the new research, the American Heart Association now says the treatment window can be extended for another 1 1/2 hours.
Extending the time that tPA, which is administered intravenously, can be used has been controversial, partly because the drug can cause serious bleeding in the brain.
But the new research showed a clear advantage, said Jeffrey Saver, who served on the Heart Association's advisory committee.
For every 100 patients treated between three hours and 4 1/2 hours, 16 got better and 2.5 got worse, he said. In the rest, there was no change.
Treating within three hours resulted in 32 patients getting better and about three getting worse, he said.
"This should convince the last skeptics and rally emergency medicine and neurology," said Saver, a professor of neurology at UCLA.
As many as 40% of ER doctors say they would not use the drug, partly because of concerns about side effects and liability.
At some hospitals there is a financial disincentive to using tPA, said Diane Book, director of the stroke program at Froedtert Hospital in Wauwatosa and an associate professor of neurology at the Medical College of Wisconsin.
Often at non-teaching hospitals, a neurologist has to be called in to determine whether tPA should be used. And that consultation is not reimbursed at its full cost by Medicare and private insurance companies, she said.
"Physicians and hospitals all over the country have found reasons not to treat," Book said.
Book said she is hopeful that the new research and the advisory statement will push more hospitals toward using tPA.
"This gives all docs who are dragging their feet more evidence to give this treatment," she said. "To withhold this treatment is wrong."
The study was funded by the National Institutes of Health. One author of the study works for Boehringer Ingelheim Pharma, which makes tPA, and lead author Lansberg has received financial support from the company.