A 3-year study of more than 1,000 patients found that the risk of
delayed intracranial hemorrhage and death following head trauma was
significantly higher for adults taking older blood thinning medications
including clopidogrel (Plavix) and warfarin (Coumadin), according to
research being presented today at the annual meeting of the Radiological
Society of North America (RSNA). Taking aspirin concurrently with any blood thinner may increase the risk of delayed hemorrhage.
Intracranial hemorrhage occurs when blood vessels within the brain
rupture, releasing blood into the brain tissue. In a delayed traumatic
intracranial hemorrhage, bleeding in the brain occurs after the initial
trauma, usually within 48 hours, after an initial negative head CT.
High blood pressure, head injury and the use of blood thinners are
known causes of intracranial hemorrhage. As the population ages, the
prevalence of patients taking blood thinners is increasing.
“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,” said Warren Chang MD,
neuroradiologist and director of research at the Imaging Institute of
the Allegheny Health Network in Pennsylvania. “This is an active area of
investigation, especially as novel blood thinners become more widely
Adults taking blood thinners who suffer head trauma typically undergo
CT imaging of the brain. However, the standard of care beyond initial
imaging is not well defined. 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,” Dr. Chang said.
In the retrospective analysis, researchers reviewed the records of
all patients taking blood thinners who suffered head trauma and
underwent CT imaging in the Allegheny Health Network between January 1,
2017, and January 1, 2020. Patients were included in the study if
initial CT imaging was negative for intracranial hemorrhage and repeat
imaging was subsequently performed. The final study group of 1,046
patients included 547 women and 499 men with an average age of 77.5.
Within the study group, 576 patients were taking one of the newer
blood thinners, such as apixiban (Eliquis), rivaroxaban (Xarelto) and
dabigatran (Pradaxa), and 470 patients were taking warfarin, clopidogrel
or another older medication.
Overall, there was 1.91% incidence (20 patients) of delayed
hemorrhage and 0.3% mortality rate (3 patients). All deaths in the study
group were among patients in the warfarin/clopidogrel/older blood
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 9 of
the 15 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,” Dr. Chang
Among the 5 patients taking novel blood thinners who experienced a delayed hemorrhage, 4 were also taking aspirin.
“Given the high volume of our trauma patients taking aspirin and
anticoagulants, this study will help to guide our care of closed head
injury patients in emergency medicine and support efforts to use imaging
resources appropriately,” said Thomas Campbell MD MPH, the
system chair for Emergency Medicine of the Allegheny Health Network.
Based on the findings, the study’s authors 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.
“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,” Dr. Chang
“This study illustrates how innovative imaging can drive optimal
patient care. In the end, I believe the recommendations of this work
will save many lives,” said Bethany Casagranda DO, chair of the
Imaging Institute of the Allegheny Health Network.
Source: News Release
Radiological Society of North America
November 30, 2021