Head Trauma Patients on Blood Thinners Need Surveillance

CHICAGO — Individuals on blood thinners such as clopidogrel and warfarin who experience head trauma may suffer delayed bleeding into the brain that at first may not be detected on imaging, a researcher reported.

In a retrospective study, about 2% of patients with head trauma who had negative imaging for intracranial hemorrhage at first admission later developed bleeding, said Warren Chang, MD, director of research at the Imaging Institute of Allegheny Health Network in Pittsburgh.

“The incidence of delayed posttraumatic intracranial hemorrhage in patients on different types of blood thinners with and without the addition of aspirin is not well established,” he explained in a presentation at the Radiological Society of North America annual meeting, conducted this year both in person and online. “This is an active area of investigation, especially as novel blood thinners become more widely adopted.”

Adults taking blood thinners who suffer head trauma typically undergo CT imaging of the brain, but the standard of care beyond initial imaging is not well defined, Chang noted. Some hospitals admit patients for observation and repeat CT imaging, while others may discharge a patient who does not have intracranial hemorrhage and is in stable condition.

“Different hospital networks have different strategies for repeat imaging of these patients,” he said.

The study will change clinical practice, predicted Max Wintermark, MD, chief of neuroradiology at Stanford University in California.

“I think that this study will definitely have a clinical impact,” he told MedPage Today. “We typically base the follow-up CT scanning on the clinical observation of traumatic brain injury patients, watching for any change in their neurological status. This study will guide us to pay extra attention to patients who are taking blood-thinners.”

Chang and his colleagues reviewed data accrued over a 3-year period — from 2017 to 2020 — in the Allegheny Health Network. Patients were included in the study if initial CT imaging was negative for intracranial hemorrhage and repeat imaging was subsequently performed. Eventually, a total of 1,046 patients were included. Their average age was 77.5; 547 of the patients were women and 499 were men.

A total of 576 patients were taking one of the newer blood thinners, such as apixiban (Eliquis), rivaroxaban (Xarelto), or dabigatran (Pradaxa), and 470 were taking warfarin, clopidogrel, or another older medication. Among the total study group, 345 patients were taking both blood thinners and aspirin.

Overall, 20 patients (1.91%) had a delayed incidence of hemorrhage; three of those patients died — all in the older blood thinner group. Fifteen of the individuals were taking an older type of blood thinner, nine of which were also taking aspirin. Among the five patients on novel blood thinners who had a delayed hemorrhage, four were also taking aspirin.

“The rate of delayed hemorrhage was higher in patients taking older blood thinners compared with novel drugs, and significantly higher in patients taking aspirin in addition to the older medications,” Chang said.

Chang said that based on the findings, he and his colleagues recommend follow-up CT for patients who had no initial intracranial hemorrhage from head trauma who are taking one of the older blood thinners and for patients who take any blood thinner along with aspirin. Unless there are external signs of trauma, follow-up CT is unnecessary for patients who take one of the newer blood thinners and do not take aspirin, Chang suggested.

“Taking any blood thinner concurrently with aspirin significantly increased the risk of delayed hemorrhage, while taking one of the novel medications without aspirin significantly reduced the risk,” he added.