Stroke patients on long-term blood thinners who were given the clot-busting drug alteplase enjoyed better recoveries than those who did not receive the drug and had no increased risk of bleeding, a new study led by UTSW researchers shows. The results run counter to the common practice of withholding the clot-busting drug to these patients due to concerns over complications from bleeding.

Many patients at risk of heart attack or stroke from nonvalvular atrial fibrillation take widely used blood thinners known as non-vitamin K antagonist oral anticoagulants (NOACs) to reduce the risk of stroke. But clinicians have been hesitant to give alteplase, the only approved medical therapy for acute ischemic stroke, to patients on blood thinners who have a stroke, believing it would cause excess bleeding such as a brain hemorrhage.

Published in JAMA, the study of more than 160,000 patients—the largest of its kind—found 2,207 patients who were taking NOACs prior to having a stroke and were treated with alteplase. It found no evidence that the patients were at risk of excess bleeding. Instead, they were able to return home free of disabilities and able to ambulate and function independently.

"The real risk is in not treating patients—they would otherwise be left with lifelong disability from their stroke," said Ying Xian, MD, PhD, an author of the study, Associate Professor of Neurology and Population and Data Sciences, and Section Head of Research, Stroke and Cerebrovascular Diseases.

Approved in early 2010s, NOACs such as dabigatran, rivaroxaban, apixaban, and edoxaban made up nearly 80% of new blood thinner prescriptions in 2017, and that number is believed to be higher now, Dr. Xian said. A clinical trial of alteplase in NOAC patients is unlikely, so Dr. Xian and his colleagues studied data from 163,083 patients across the United States in the American Heart Association's Stroke Registry.

Other UT Southwestern researchers who contributed to the study are DaiWai Olson, PhD, RN, and Eric Peterson, MD, MPH, Vice Provost and Senior Associate Dean for Clinical Research and Professor of Internal Medicine.