Venous thromboembolism (VTE) occurs when blood clots form within the venous system. DVT may occur if the clot forms in a deep vein (i.e., in the leg). If the clot broke off and travelled to the lungs, causing partial or full occlusion, it can become a pulmonary embolism (PE) (Office of the Surgeon et al. 2008). VTE remains a common complication in patients who have sustained an ABI (Raslan et al. 2010; Scudday et al. 2011); however the scientific literature specific to ABI is quite limited.
Incidence of Venous Thromboembolism Post-Head Injury
In a large sample study, 38,984 individuals with TBI, the incidence of VTE at the time of admission was 1.31% (Olufajo et al. 2016). At one month post injury, the incidence for VTE increased to 1.87% and by one year it was 2.83% (Olufajo et al. 2016). The reported incidence of DVT among patients with TBI
ranges from 11% to 54% (Carlile et al. 2010; Cifu et al. 1996; Denson et al. 2007; Geerts et al. 1994). The risk of developing a DVT or PE, in the absence of prophylaxis, is estimated to be approximately 20% post-TBI (Haddad & Arabi 2012) and severity of injury is found to be associated with incidence of VTE in isolated patients with TBI (Van Gent et al. 2014). Decisions on how to treat, and when, are often made on a case by case basis (Tang & Lobel 2009). Experts recommend beginning pharmacological prophylaxis as early as 48 to 72 hours post injury (Norwood et al. 2001). Unless contraindicated, mechanical thromboprophlaxis and low-molecular weight heparin (LMWH) is recommened in the acute phase of recovery (Haddad & Arabi 2012).
Cifu et al. (1996) screened 153 patients admitted to a tertiary care brain injury unit within 24 hours of admission for a lower extremity DVT with colour flow duplex Doppler ultrasonography. All patients had received prophylactic intervention with either subcutaneous heparin anticoagulation or intermittent compression devices. The overall incidence of DVTs in those patients with ABI was 13%, while individuals with TBI had an incidence rate of 20%. Most of the DVTs were asymptomatic. Another study found that DVT was present in 31.6% of individuals who sustained a head injury (Ekeh et al. 2010).