Incidence and risk factors for delayed intracranial hemorrhage after mild brain injury in anticoagulated patients: a multicenter retrospective study

Background: Anticoagulated patients with mild traumatic brain injury (mTBI) and a negative cerebral CT on admission, commonly undergo a repeated CT scan after observation in the emergency department (ED) to detect delayed intracranial hemorrhage (ICH). However, the utility of this practice is controversial, with recent evidence suggesting that the risk of delayed ICH in these patients is low. This study aims to evaluate incidence, outcomes, and risk factors of delayed ICH in patients receiving direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs) presenting to the ED with mTBI. Methods: A multicenter, observational, retrospective cohort study was conducted in the EDs of three hospitals in Northern Italy, from January 2017 to December 2021. All consecutive adult patients on DOACs or VKAs therapy, admitted for a mTBI, who underwent a second CT scan after 12–24 h from a negative first one, were enrolled. Results: A total of 1596 anticoagulated patients were enrolled, 869 (54%) on DOACs and 727 (46%) on VKAs therapy. The median age was 84 [79–88] and 56% of patients were females. The incidence of delayed ICH was 1.8% (95% CI: 1.1-3.0%; 14/869 patients) for DOACs, and 2.6% (95% CI: 1.6–4.1%; 19/727 patients) for VKAs patients, with no cases requiring neurosurgical intervention. Vomiting after head injury and the onset of new symptoms during observation were associated with a higher risk of delayed bleeding (OR 4.8; 95% CI: 1.4–16.5, and OR 4.7; 95% CI 1.2–23.7, respectively). At a 30-day follow-up, 2% of patients had a new ED admission related to their previous mTBI, with no significant difference between the groups. Conclusions: Delayed ICH is uncommon among anticoagulated patients with mTBI and has minimal impact on their outcome. Routine performance of a second CT scan may be unnecessary and may be considered only in presence of high-risk clinical risk factors or signs of deterioration.