Anticoagulants add to risk of delayed brain hemorrhage

CHICAGO—A negative imaging study on a head trauma patient doesn’t necessarily put the individual out-of-the-woods for a devastating intracranial bleed—especially if that person is on various types of blood thinners, researchers reported here.

About 2% of all patients with a negative first scan subsequently went on to have bleeding into the brain, reported Warren Chang, MD, director of research at the Imaging Institute of the Allegheny Health Network, Pittsburgh, at the annual meeting of the Radiological Society of North America.

Chang also suggested that older anticoagulant medications such as clopidogrel and warfarin are more likely to cause these delayed hemorrhages than some of the newer anticoagulation agents.

“The incidence of delayed post-traumatic intracranial hemorrhage in patients on different types of blood thinners, with and without the addition of aspirin, is not well established,” said Chang. “This is an active area of investigation, especially as novel blood thinners become more widely adopted.”

Chang reported that when a person with head trauma is brought to the emergency department, they typically undergo computer-assisted tomography (CT) scans of the brain. However, the standard of care beyond initial imaging is not well defined, he 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,” Chang said.

In the study, Chang and colleagues reviewed data accrued over a three-year period—2017 through 2020—by 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.

After determining eligibility for the study, the research team included 1,046 patients for analysis. The average age of the cohort was 77.5 years; 547 of the patients were women and 499 were men. Within the study group, 576 patients were taking one of the newer blood thinners, such as apixaban (Eliquis), rivaroxaban (Xarelto) and dabigatran (Pradaxa), and 470 patients were taking warfarin, clopidogrel or another older medication.

Overall, 20 patients, or 1.91%, experienced a delayed incidence of hemorrhage; three of those patients died. All deaths in the study group were among patients in the warfarin/clopidogrel/older blood thinner group.

Among the total study group, 345 patients were taking both blood thinners and aspirin. Of the 20 patients who suffered a delayed hemorrhage, 15 were taking an older type of blood thinner, and nine of the 15 were also taking aspirin.

Among the five patients taking novel blood thinners who experienced a delayed hemorrhage, four were also taking aspirin.

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

Based on the findings, the researchers 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 only take one of the newer blood thinners and do not take aspirin, he 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,” Chang said.

In commenting on the study, Elliot Fishman, MD, professor of radiology, of oncology, and of surgery at Johns Hopkins University, Baltimore, told BreakingMED, “When you consider this, the finding is really not that surprising. When you take patients who are on anticoagulation, we sometimes see bleeds in the abdomen that were not apparent right away.

“I would wonder if the evidence of the bleeds was apparent in the first scans, but the bleed was so subtle, that it was missed on the first read. I would like to see the researchers go back and revisit those initial scans, and see if, in retrospect, those signs were there,” Fishman said.

“The study does make the point that you do have to watch these patients carefully, even if the initial scan is negative,” he added.

John McKenna, Associate Editor, BreakingMED™

The authors disclosed no relationships with industry.

Fishman disclosed relationships with Siemen’s and GE.

Cat ID: 235

Topic ID: 98,235,254,791,730,914,38,481,235