Dr. S. Claiborne Johnston, director of the Stroke Service at the University of California, San Francisco, said a minor ischemic stroke is caused by a clot that blocks blood supply to the brain, but its effects are minimal. TIAs and minor strokes don't typically cause permanent harm, but early treatment is critical to prevent the possibility of a major stroke.
"TIAs and minor strokes are emergencies," Johnston, the study's senior author, said in a statement. "If we start dual treatment early, it looks like we can reduce the risk of another stroke by more than 30 percent."
In comparison, aspirin therapy alone cut stroke risk by about 20 percent, he said.
The American Stroke Association said if a person had one or more TIAs, they're almost 10 times more likely to have a stroke than someone of the same age and sex who hasn't.
The Plavix, or clopidogrel, study included 5,174 patients -- median age 62, 34 percent women -- with minor, clot-caused strokes or TIAs from 114 centers in China.
Within 24 hours, treatment was started with either low-dose aspirin -- 75-300 mg on the first day followed by 75 mg/day -- plus a placebo or the same aspirin regimen plus clopidogrel, an initial 300 mg load followed by 75 mg/day for the first 21 days.
The findings were presented at the American Stroke Association's International Stroke Conference.