Risk of Delayed Intracerebral Hemorrhage in Anticoagulated Patients after Minor Head Trauma: The Role of Repeat Cranial Computed Tomography

Context: Patients receiving anticoagulant medications who experience minor head injury are at increased risk of an intracerebral hemorrhage (ICH) developing, even after an initial computed tomography (CT) scan of the brain yields normal findings. Conflicting evidence exists regarding the frequency at which delayed bleeding occurs. Objective: To identify the frequency of delayed traumatic ICH in patients receiving warfarin or clopidogrel. Design: We performed a retrospective observational study of adult trauma encounters for anticoagulated patients undergoing head CT at 1 of 13 Kaiser Permanente Southern California Emergency Departments (EDs) between 2007 and 2011. Encounters were identified using structured data from electronic health and administrative records, and then records were individually reviewed for validation of results. Main Outcome Measures: The primary outcome measure was ICH within 60 days of an ED visit with a normal head CT result. Results: Our sample included 443 (260 clopidogrel and 183 warfarin) eligible ED encounters with normal findings of initial head CT. Overall, 11 patients (2.5%, 95% confidence interval [CI] = 1.4%-4.4%) had a delayed ICH, and events occurred at similar rates between the clopidogrel group (6/260, 2.3%, CI 1.1%-5.0%) and warfarin group (5/183, 2.7%, CI 1.2%-6.2%). Conclusion: Trauma patients in the ED who are receiving warfarin or clopidogrel have approximately a 2.5% risk of delayed ICH after an initial normal finding on a head CT.