Evaluation of the yield of 24-h close observation in patients with mild traumatic brain injury on anticoagulation therapy: a retrospective multicenter study and meta-analysis

Patients with mild traumatic brain injury (mTBI) on anticoagulants have an increased risk of intracranial hemorrhage (ICH). However, consensus is lacking on whether to admit them after normal initial cranial CT. We evaluated the yield of 24-h neurological observation. Retrospective multicenter study including adult patients admitted over a 5-year period with mTBI on anticoagulation [therapeutic dose heparin, direct oral anticoagulant, or vitamin K antagonist (VKA) with international normalized ratio (INR) >= 1.7] and reportedly normal cranial CT obtained within 24 h after trauma. Primary endpoint was symptomatic ICH within 24 h of injury. Literature on delayed ICH in patients with mTBI and anticoagulation use was reviewed. Of 17.643 mTBI patients, 905 met the inclusion criteria (median age 82 years). 97% used VKA (median INR 2.9). None developed delayed ICH within 24 h. Nine patients deteriorated neurologically due to ICH, four within 24 h (0.4%, 95% CI 0.1-1.2) and five on day 2, 18, 22, 36 and 52, respectively. In six patients, including all four that developed symptoms within 24 h, ICH was found upon reevaluation of initial imaging. The meta-analysis comprised of 9 studies with data from 2885 patients. The estimated pooled proportion of symptomatic delayed ICH or delayed diagnosis of ICH within 24 h was 0.2% (95% CI 0.0-0.5). Delayed (diagnosis of) ICH within 24 h is very rare in mTBI patients on anticoagulants after reportedly normal initial CT. Routine hospitalization of these patients seems unwarranted when the initial cranial CT is scrupulously evaluated.