Retrospective evaluation of chemical venous thromboembolism prophylaxis in traumatic brain injury

Background: Traumatic brain injury (TBI) is a risk factor for venous thromboembolism (VTE) but few studies address optimal timing or choice of agent. Materials and Methods: Retrospective review of moderate to severe TBI patients receiving chemical VTE prophylaxis (early initiation [<= 72 h from admission], late [> 72 h to 7 days], or delayed [> 7 days]) between 2012 through 2017. Primary outcome was VTE occurrence. Secondary objectives evaluated intracranial hemorrhage (ICH) requiring cessation of prophylaxis and differences between unfractionated (UFH) and low-molecular weight heparin (LMWH). Results: A total of 198 patients were evaluated; median age was 44 years (IQR 25-60), median Glasgow Coma Scale score 3 (IQR 3-7), and median injury severity score 27 (IQR 22-34). Ten percent of patients (n = 20) developed VTE. Median time to VTE prophylaxis was 81 h (IQR 53-152) and there was no difference in VTE incidence across all groups (p = 0.09). Intergroup comparison showed patients that received early prophylaxis had lower VTE rates (6% vs. 16%, p = 0.04) and mortality (3% vs. 15%, p = 0.02) compared to late initiation (but not delayed). There were no instances of new onset or expanded ICH requiring cessation of prophylaxis. VTE rates for patients receiving UFH only or LMWH only, 14/115 (12.2%) vs. 3/46 (6.5%), were not different (p = 0.4). Mortality was lower in the LMWH only group (0% vs. 13.0%, p<0.01). Conclusions: Initiating VTE prophylaxis within 72 h of moderate to severe TBI appears to be safe and may be associated with lower rates of VTE and mortality.