Study Shows More Americans Are Now Using tPA in the Hours After a Stroke
By Kathleen Doheny
WebMD Health News
Reviewed By Laura J. Martin, MD
June 2, 2011 -- The use of a clot-busting drug for stroke has increased in the U.S., according to a new study. However, its overall use is still low.
Known as tPA, the clot buster is approved to treat the type of stroke caused by a blood clot in the brain, known as ischemic stroke.
"At the end of 2004, 1.8% to 2.1% of all ischemic stroke patients received tPA," says researcher Opeolu Adeoye, MD, assistant professor of emergency medicine and neurosurgery at the University of Cincinnati.
"Using the exact same methodology, at the end of 2009, we found 3.4% to 5.2% of all ischemic stroke patients received tPA."
That is a little more than a doubling, comparing the upper estimates, he says.
The study is published in Stroke: Journal of the American Heart Association.
"I think this is great news for stroke patients," Adeoye says. "But we still have to acknowledge that very few patients, relatively speaking, are receiving the drug."
How tPA Works
The FDA approved tPA, or tissue plasminogen activator, for ischemic stroke treatment in 1996.
The drug works by breaking up the clot. However, time is critical, says Adeoye. The drug can only be given up to 4.5 hours after the first stroke symptoms occur, he says. Ideally, the drug should be given within an hour after the stroke symptoms begin.
Many experiencing those symptoms ''tend to not come to the hospital," says Adeoye. The symptoms can include confusion, dizziness, trouble seeing out of one eye or talking, lack of coordination, and weakness of a body part, especially on just one side of the body.
For the study, Adeoye used Medicare records and pharmacy billing codes. Next, he assumed that some billing errors occurred, leading to the upper estimates.
About 795,000 Americans have strokes annually, according to the American Heart Association. About 85% of them are strokes caused by clots. Many factors play a role in the increased use of tPA, Adeoye tells WebMD. One is the rise in stroke centers, such as those certified by the Joint Commission, which accredits health care facilities.
"Many states have led initiatives to improve stroke care," Adeoye says. Adeoye reports that he serves on the speaker's bureau and is a consultant for Genentech, which makes tPA. The study was funded by the American Association of Medical Colleges.
Ask for tPA, Expert Says
"I think this is terrific news that the use of the most effective drug for acute [ischemic] stroke is up," says Ralph Sacco, MD, president of the American Heart Association and chair of neurology at the University of Miami Miller School of Medicine.
"We used to quote numbers like 1%," he tells WebMD. "Now the numbers could be as high as 5.2%."
He agrees that the growing number of hospitals equipped to care for stroke is one major reason for the increase.
"Nearly 85% of people in the U.S. live within 60 minutes of an acute stroke hospital," he says, citing American Heart Association statistics.
"The biggest issue is still public awareness of stroke symptoms," he says. "The public still doesn't recognize stroke quickly enough."
Some stroke patients will not be able to get tPA, he says, because they have surpassed the 4.5-hour window.
Even within an ideal time window, not everyone is a candidate for tPA, Sacco says. Those on certain blood thinners, for instance, may not be approved if there is a risk of bleeding that could bring on brain hemorrhage.
He offers this advice to those who think they may be having a stroke and their loved ones: "Call 911. Know where the closest stroke center is. Be aware of treatments. Ask, 'Can I have the clot buster?'"
He reviewed the study findings for WebMD but did not take part in the research.
Opeolu Adeoye, MD, assistant professor of emergency medicine and neurosurgery, University of Cincinnati.
Adeoye, O. Stroke: Journal of the American Heart Association, published online June 2, 2011.
Ralph Sacco, MD, chair of neurology, University of Miami Miller School of Medicine; president, American Heart Association.
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