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TBI + DOACs = Delayed Head CT?

February 8, 2022

Written by Sam Parnell

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Delayed intracranial hemorrhage for patients on direct oral anticoagulant therapy with minor traumatic brain injury is rare (~1.5%) after a negative initial head CT.

Why does this matter?
Patients taking direct oral anticoagulant therapy (DOACs) have increased risk of bleeding after minor traumatic brain injury (mTBI). However, recent evidence suggests that the overall risk of intracranial hemorrhage (ICH) for patients taking DOACs after mTBI is low. Furthermore, studies of patients taking vitamin K antagonists report only a small risk of delayed ICH after mTBI (less than 2%), but can this data be extrapolated to patients taking DOACs? Are these patients at high risk for delayed ICH, and do they all need repeat CT scan after 24 hours to ensure a safe discharge?

Waiting 24 hours for a repeat head CT scan is such a headache…
This was a retrospective, multicenter, observational study of 5 EDs in northern Italy from January 1, 2016 to February 1, 2020. The study included patients on DOACs with mTBI defined as “any closed trauma of the craniofacial region associated with a Glasgow Coma Scale (GCS) score of 14–15 at presentation regardless of loss of consciousness immediately after the trauma.” A total of 1,426 patients taking DOACs were included in the study. Most patients included in the study were taking direct factor Xa inhibitor therapy (67.3%), and apixaban and rivaroxaban were the most commonly prescribed DOACs. Atrial fibrillation was the most common reason for DOAC use (90.3%), and accidental fall was the most common modality of trauma (74.9%).

Initial CT head was positive for ICH in 6% of patients (85/1426). Of the patients with an initial negative head CT (n = 1,341), 68.3% (916/1341) underwent a second CT after 24 hours of observation. Overall, only 1.5% of patients (14/916) who had a repeat head CT scan were found to have delayed ICH, and no patients with delayed ICH required neurosurgical intervention or died. Risk factors associated with diagnosis of delayed ICH were post-traumatic loss of consciousness and post-traumatic amnesia. None of the patients evaluated 8 hours after trauma with a negative initial head CT developed delayed ICH.

This study had several limitations given its retrospective design and potential confounders. In addition, a repeat CT was not performed on all patients with a negative initial CT. Instead, the decision to perform a repeat CT was left to the treating physician. However, this could mean that the patients who had a repeat head CT scan were thought to be higher risk than those who did not have a repeat scan.

This study suggests that delayed ICH after mTBI for patients taking DOACs with a negative initial head CT is rare and not associated with death or the need for neurosurgical intervention. Therefore, repeat head CT does not seem to significantly affect patient outcome and may be unnecessary in most instances. Clinical risk factors associated with delayed ICH such as post-traumatic loss of consciousness and post-traumatic amnesia could help determine the need for repeat imaging or observation.

Risk of delayed intracranial haemorrhage after an initial negative CT in patients on DOACs with mild traumatic brain injury. Am J Emerg Med. 2022 Jan 15;53:185-189. doi: 10.1016/j.ajem.2022.01.018. Online ahead of print.