1114 Timing of Pharmacologic Venous Thromboembolism Prophylaxis After Firearm-Related Penetrating Brain Injury

INTRODUCTION: Mounting evidence supports early initiation of pharmacologic venous thromboembolism (VTE) prophylaxis after traumatic brain injury. However, the effectiveness and safety of VTE prophylaxis after penetrating brain injury (PBI) is unclear. METHODS: This was a retrospective cohort study of adult patients with isolated firearm-related PBI treated at level I/II trauma centers participating in ACS Trauma Quality Improvement Program (2017–2019). The exposure was the timing of VTE prophylaxis initiation measured in days (prophylaxis delay). The primary outcome was VTE. Secondary outcomes were the need for late neurosurgical decompression and mortality. Hierarchical logistic regression estimated the association between prophylaxis delay and the outcomes after adjusting for patient baseline and injury characteristics. Effect modification was tested to determine if observed associations varied by type of early neurosurgical intervention. RESULTS: We identified 2,012 patients with firearm-related PBI. After risk-adjustment, each additional day of prophylaxis delay was associated with 6% increased odds of VTE (OR 1.06 per day; 95%CI 1.02-1.11). However, the association between prophylaxis delay and late neurosurgical decompression depended on type early neurosurgery. Earlier prophylaxis was associated with higher risk of late neurosurgical decompression among patients that underwent intracranial monitor/drain insertion or no intervention, such that each day of prophylaxis delay conferred 49% (OR 0.51; 95%CI 0.35-0.75) and 15% (OR 0.85; 95%CI 0.75-0.95) decreased odds of late decompression respectively in these groups. Timing of prophylaxis was not associated with late neurosurgical decompression for patients that underwent early craniotomy/craniectomy. There was no association with mortality. CONCLUSIONS: Among patients with firearm-related PBI, earlier pharmacologic prophylaxis was associated with decreased odds of VTE. However, earlier prophylaxis was also associated with late neurosurgical decompression among patients with intracranial monitor/drain placement or no intervention, an effect not observed for patients that underwent early craniotomy/craniectomy.