Mini-Stroke Can Mean Major One Within Hours
MONDAY June 1, 2009 -- About half the people who have a major stroke soon after a less serious brain event, such as a transient ischemic attack or "mini-stroke," do so within 24 hours of the minor event, a new study finds.
The message here for people who have a TIA is to "seek medical attention immediately, particularly if you have either weakness or speech disturbance that lasts more than 10 minutes," said the study's senior author, Dr. Peter M. Rothwell, a professor of clinical neurology at the University of Oxford in England.
"Don't wait until the next day -- it may be too late," he said.
Reporting in the June 2 issue of Neurology, Rothwell and his colleagues looked at the medical records of 1,247 people who had a TIA, which is a momentary blockage of blood flow in a brain artery.
Of those, 35 went on to have recurrent strokes within the next 24 hours. In that group, 1.2 percent of the second strokes occurred within six hours, 2.1 percent within 12 hours and 5.1 percent within 24 hours, the team found.
"That about half of all the recurrent strokes in the seven days after a TIA occur in the first 24 hours highlights the need for emergency assessment," the researchers wrote.
That assessment should look at the well-established "ABCD2" stroke risk factors, Rothwell said. These include:
- A: age over 60
- B: blood pressure reading that is high
- C: clinical symptoms of physical weakness
- D: duration of the TIA
"Patients should be investigated and treated as an emergency, certainly those with a high ABCD2 score," Rothwell said.
While TIAs and minor strokes are well known to be warning signs of major trouble ahead, "no study has shown how high the risk is in the first few hours -- i.e., that TIA and minor stroke is a true neurological emergency," he said.
Immediate action can lessen the risk, Rothwell said. "We published a paper in Lancet in November 2007 looking at the benefits of emergency treatment versus standard treatment," he said. "We showed that the risk of major stroke can be reduced by up to 80 percent simply by initiating standard treatment as an emergency measure -- aspirin plus or minus clopidogrel [Plavix], statin therapy, blood pressure reduction."
Clopidogrel and aspirin are both aimed at the clots that can cause a stroke by blocking a brain artery. Statins are drugs such as Crestor, Lipitor and Zocor that lower blood cholesterol levels.
Brain images can illustrate why risk of a recurrence might be highest in the hours after a TIA or minor stroke, Rothwell pointed out. "When we do perfusion [blood flow] brain scans in these patients, we do sometimes find that they have occluded an artery in the brain with a blood clot but the brain is surviving on indirect blood flow from the other vessels," he said. "After a few hours, this indirect blood flow sometimes fails and the affected brain area then dies -- they have a stroke."
Dr. Howard S. Kirshner, vice chairman of neurology and director of the Stroke Center at Vanderbilt University Medical Center and a spokesman for the American Academy of Neurology, agreed that "all of this supports the idea that TIA is a medical emergency, that patients who experience a TIA need to seek medical attention right away."
"For the emergency department, TIA patients should not be sent right home but should be kept for observation and tested," he said. "They can be sent home if the tests are negative and they already are started on a secondary stroke prevention regimen."
Dr. Daniel Laskowitz, an associate professor in neurology at Duke University, said that the study is important because it marks a new emphasis on prevention in stroke medicine.
Once a stroke occurs, treatment options are limited, so where the effort needs to go is stroke prevention, Laskowitz said. And this adds to a body of literature that if you have a TIA, you are at very high risk of a stroke."
"A TIA should send a strong warning. It is not something that needs to be seen next week," Laskowitz stressed. "There are clear interventions that we can perform to prevent a stroke. So this has a direct practical application to how we manage stroke.
The American Heart Association has more about symptoms and treatment for TIA.
Posted: June 2009