Researchers analyzed hospital records from 437 patients diagnosed with mild ischemic stroke at 16 sites in the Greater Cincinnati/Northern Kentucky region in 2005. The patients arrived at the hospital within the 3.5 hours, well within the 4.5 hour window for treatment with intravenous tissue plasminogen activator (tPA).

The federal government has approved the clot-busting drug for strokes caused by blood clots, known as ischemic stroke, which accounts for 87 percent of all strokes. It's the only acute stroke drug that can reduce disability but remains unproven for treating mild stroke.

"Currently, there is no standard of treatment for patients with the mildest strokes, even if they come into the emergency department quickly enough for intravenous tPA, the only proven treatment for a more serious stroke," said Pooja Khatri, M.D., lead researcher of the study and associate professor in the Department of Neurology and director of acute stroke at the University of Cincinnati Academic Health Center in Ohio.

"The pivotal randomized trials that proved tPA's usefulness excluded mild stroke patients because it was thought that they generally did well and the risk of tPA treatment, which includes a slight but significant risk of life-threatening bleeding in the brain, would not be worth the benefit," she said.

Only four of the mild stroke patients (less than 1 percent) received tPA. The researchers identified 150 of the remaining patients as likely candidates for the drug if the mildness of their stroke was disregarded as a reason to deny them tPA treatment.

Based on the findings, the researchers then excluded those with baseline disability (estimated at 37 percent) and assumed that 8 percent to 13 percent of the remaining mild stroke patients would regain independence after their stroke if tPA was as effective as it was in more serious cases.

Extrapolating to the U.S. population, the researchers said that if tPA proves effective, 2,176 to 3,761 fewer patients would be disabled from mild stroke each year -- saving an estimated $200 million in disability expenditures.

In the last five years, researchers conducting several studies have found that about a third of patients who experienced so-called mild strokes remained disabled three months after initial hospitalization.

"It was believed that patients with milder strokes would recover from these events," Khatri said. "These findings raise the question of whether the mildest strokes should be treated with intravenous tPA."

Co-authors are: J.C. Khoury, Ph.D.; Kathleen Alwell, R.N.; Charles J. Moomaw, M.S.; Brett M. Kissela, M.D.; Daniel Woo, M.D.; Matthew L. Flaherty, M.D.; Ope Adeoye, M.D.; Simona Ferioli, M.D.; and Dawn O. Kleindorfer, M.D. Author disclosures are on the abstract.

The National Institutes of Health funded the study.

Note: If no author is given, the source is cited instead.

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