After suffering a stroke or a mini-stroke, patients are usually given aspirin to prevent clots that can cause another stroke. Now a new study suggests that adding the drug Plavix (clopidogrel) to the mix can reduce the risk of a second stroke by nearly a third over aspirin alone.
Both drugs target clotting agents in the blood, called platelets, preventing them from grouping together and forming clots. The drug combination is commonly used after a heart attack, but until now there hasn't been enough data to suggest it would work in stroke or mini-stroke, officially known as a transient ischemic attack (TIA).
"Giving two drugs that block platelets works a lot better than aspirin alone in people who have had a minor stroke or TIA," said researcher Dr. S. Claiborne Johnston, a professor of neurology at the University of California, San Francisco.
The trial was done in China, so whether the results would be the same in the United States isn't known. "They probably are, but we would like to see them confirmed," Johnston said.
To do so, a similar trial is under way in the United States with Johnston as the lead investigator. "We should have confirmation or no confirmation within a few years," he said.
Some doctors are treating stroke patients with this combination of drugs now, Johnston said. "This combination may be something [other] doctors can consider," he said.
The report was published June 26 in the online edition of the New England Journal of Medicine.
Most strokes are caused by blood clots that block blood vessels in the brain. These are called ischemic strokes. A TIA is also caused by a clot that dissipates in a short time. Both leave patients at risk for another stroke that could be more severe, the researchers said.
In the new phase 3 trial, more than 5,000 patients who had suffered a stroke or TIA within the previous 24 hours were randomly assigned to take either aspirin alone or aspirin plus Plavix for three months.
This three-month period is the most critical for repeat strokes, with 10 percent to 20 percent of people who have a TIA or minor stroke suffering a second stroke, the researchers said.
Within three months of starting the study, 8.2 percent of the patients taking the two-drug combo had another stroke, compared with 11.7 percent of those taking aspirin alone, the researchers found.
Dr. Rafael Alexander Ortiz, director of neuro-endovascular surgery and stroke at Lenox Hill Hospital in New York City, said these findings are important and, if confirmed, will change standard practice for some stroke patients.
"This is great news in terms of a positive outcome," said Ortiz, who was not involved with the study.
Recently, doctors have moved away from using this combination of drugs for long-term stroke treatment because of the increased risk of serious bleeding, he said.
"Now we can see there is a definite benefit of the combined use of aspirin and Plavix in the acute phase of stroke," Ortiz said.
He said this treatment appears most effective in patients who have suffered a minor stroke or TIA. "If the results of other trials are similar to what we saw in this one, more people will use this therapy," he said. "It offers more tools and better options to offer patients."
Dr. Ralph Sacco, chairman of neurology at the University of Miami Miller School of Medicine, said the study "provides some very convincing data on the efficacy of clopidogrel and aspirin in the acute phases after TIA or minor stroke compared to aspirin among Chinese patients." He also noted that TIA patients are at a high risk for stroke.
Sacco said that in previous studies, the drug combination has not been found effective in long-term treatment to prevent a second stroke. However, he added, "this trial offers hope that in the short term, combination [drugs] may be worth the increased bleeding risk to improve outcomes."
He mentioned current studies that "continue to assess this more aggressive [combination drug] option among U.S. patients, since Chinese patients could have different stroke subtypes and higher risks of recurrence."
Study author Johnston acknowledged that his later U.S. trial is important because differences in genetics, risk factors and medical practice in China could mean different results for different countries.
If in a few years the U.S. results turn out the same as those of the China-based study, giving stroke and TIA patients Plavix along with aspirin will likely become standard therapy, he said.
Stroke is a major cause of death and disability around the world, and the fourth leading cause of death in the United States.
More than 795,000 Americans have strokes every year, and in 2008 some 133,000 were fatal, according to the U.S. Centers for Disease Control and Prevention. In addition, about 300,000 Americans have TIAs each year.