Objective: Mounting evidence supports early initiation of pharmacological venous thromboembolism (VTE) prophylaxis after traumatic brain injury. However, the effectiveness and safety of VTE prophylaxis after penetrating brain injury (PBI) is unclear. The objective of this study was to evaluate the effectiveness and safety of pharmacological VTE prophylaxis in patients with firearm-related PBI.
Methods: This was a retrospective cohort study of patients aged ≥ 16 years with isolated firearm-related PBI treated at level I or II trauma centers participating in the American College of Surgeons Trauma Quality Improvement Program (2017-2019). The exposure was the timing of VTE prophylaxis initiation measured in days from admission (prophylaxis delay). The primary outcome was VTE. Secondary outcomes were the need for late neurosurgical decompression (craniotomy/craniectomy after 48 hours) and in-hospital 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: craniotomy/craniectomy, intracranial monitor/drain placement, or no intervention.
Results: The authors identified 2012 patients with isolated firearm-related PBI. The median presenting Glasgow Coma Scale score was 8 (IQR 3-14) and 31% had an abnormal pupillary response. Nearly half of the cohort received early neurosurgical intervention (craniotomy/craniectomy, 40%; intracranial monitor/drain, 8%). The median VTE prophylaxis delay was 3 days (IQR 2-5 days). VTE occurred in 6% of patients. Overall, late neurosurgical decompression was required in 9%, and 10% died. 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 timing of prophylaxis and late neurosurgical decompression depended on type of early neurosurgical intervention. Specifically, each day of prophylaxis delay was associated with decreased odds of late decompression among patients who underwent intracranial monitor/drain only (OR 0.51, 95% CI 0.35-0.75) or no intervention (OR 0.85, 95% CI 0.75-0.95). Timing of prophylaxis was not associated with late neurosurgical decompression for patients who underwent early craniotomy/craniectomy. There was no association with in-hospital mortality.
Conclusions: Among patients with firearm-related PBI, earlier pharmacological prophylaxis was associated with decreased odds of VTE. However, earlier prophylaxis was also associated with late neurosurgical decompression among patients who underwent intracranial monitor/drain placement or no intervention, an effect not observed for patients who underwent early craniotomy/craniectomy. These findings suggest that while early prophylaxis should be prioritized, prospective study is needed to clarify safe timing of initiation in different patient groups.
Keywords: firearm; penetrating brain injury; trauma; traumatic brain injury; venous thromboembolism prophylaxis.