Vena Cava Filters (VCFs) are an invasive form of thromboembolic prophylaxis that primarily function to prohibit PE while allowing venous blood flow to continue through the IVC. Earlier filters were placed surgically through the femoral vein; currently, less invasive techniques exist, allowing for filter placement through femoral, internal jugular, or small peripheral veins under fluoroscopic or ultrasound guidance (Jundt et al. 2014; Tai et al. 2013).
While pharmacological and mechanical methods remain the primary forms of thromboprophylaxis used in acute SCI, the use of VCFs is indicated in trauma individuals who are considered to be at high risk for developing DVT, specifically when there are contraindications to using anticoagulation (e.g., bleeding risk) or mechanical prophylaxis (e.g., external fixators or immobilizers are present). The ability to retrieve IVC filters offers the benefit of the filter during periods when PE risk is high, without long-term complications associated with their use (Lo et al. 2013; Rogers et al. 1993; Shackford et al. 2007). Routine implementation of IVC filters is not recommended as prophylaxis in SCI individuals (Maxwell et al. 2002).
Five studies have examined the prophylactic effect of IVC filter insertion on the incidence of DVT and/or PE after SCI. Roberts and Young (2010) conducted a case series study of individuals who received IVC filters within 72 hours of admission. The authors observed no occurrences of PE or other complications. These findings were supported by two pre-post studies by Wilson et al. (1994) and Rogers et al. (1995), who observed that inferior VCF insertion “as soon as clinically feasible” and on average 4.3 days after admission, respectively, did not result in any occurrences of PE. However, it should be noted that, in the latter study, individuals were not on any other forms of prophylaxis concurrently and as a result three individuals developed DVT. A case control study by Kinney et al. (1996) compared SCI individuals who received IVC filters to non-SCI individuals (historical controls) who also received filters. The authors found that the SCI patient population had a higher rate of PE occurrence, although statistical analysis was not conducted.
Interestingly, a retrospective case control study by Gorman et al. (2009) compared SCI individuals who had received IVC filters during acute hospitalization with SCI individuals who had not received filters. The authors found that the incidence of DVT was significantly higher in individuals with implanted filters (p=0.021).
There is level 3 evidence (from two case controls; Gorman et al. 2009; Kinney et al. 1996) that inferior vena cava filter placement does not prevent occurrences of venous thromboembolism in acute SCI individuals; However, there is level 4 evidence (from two pre-posts and one case series; Roberts and Young 2010; Rogers et al. 1995; Wilson et al. 1994) that inferior vena cava filter placement is effective in the prevention of pulmonary embolism in acute SCI individuals.
Inferior vena cava filters may reduce the risk of pulmonary embolism during the acute phase post SCI.