May 23, 2012

When Is It Safe to Use tPA With Patients on Warfarin?

Atlanta, GAThe use of the clot-busting drug tissue plasminogen activator (tPA) in patients with acute ischemic stroke already taking the blood thinner warfarin is safe, according to research presented at the American Heart Association's Quality of Care and Outcomes Research Scientific Sessions 2012.

"Although it's the only drug approved by the FDA to treat acute ischemic stroke, tPA is underused among patients on home warfarin therapy mainly because of the fear that it will cause bleeding," said Ying Xian, MD, PhD, the study's lead author and a research fellow at Duke Clinical Research Institute in Durham, North Carolina.

Using data from 23,437 ischemic stroke patients treated with tPA in 1,203 hospitals between April 2009 and June 2011 (participants in the American Heart Association/American Stroke Association's "Get With The Guidelines" stroke registry), researchers evaluated tPA safety in warfarin-treated patients. Nearly 8% of the patients were taking warfarin prior to admission, and they tended to be older77 years versus 71 yearsto have more comorbid conditions, and to have suffered more severe strokes.

Despite that, the risk of severe bleeding from brain hemorrhage was found to be similar among patients who received tPA after stroke, regardless of whether they were on warfarin, according to the presentation.

Researchers also didn't find significant differences between warfarin and nonwarfarin patients when comparing risks of tPA-related complications or in-hospital death after tPA.

"Our study suggests tPA is not associated with excessive bleeding or death among warfarin patients, when used according to American Heart Association/American Stroke Association guidelines," Xian said. "tPA has been shown to minimize brain damage and disability from stroke and should not be withheld from these patients."

The study is the largest on the safety of tPA in warfarin-treated patients who meet clinical guideline criteria. Xian noted that the study was limited, however, in that it did not measure functional, neurological, or long-term results of tPA treatment.

Warfarin use may eventually decline, in any case, because of evidence that new oral anticoagulants are more efficacious for the prevention of stroke and systemic embolism in patients with atrial fibrillation. Another new study, published recently in the American Journal of Cardiology, found that their decreased risk for intracranial bleeding gives them a more favorable safety profile and makes them promising alternatives to warfarin.

U.S. Pharmacist Social Connect