Original title: The effectiveness of prophylactic inferior vena cava filters in trauma patients: a systematic review and meta-analysis. Reference: Haut ER et al. JAMA Surg. 2014;149:194-202.

Trauma is one of the strongest risk factors for pulmonary embolism (PE). Current guidelines recommend low molecular weight heparin therapy which have been proved effective; however, trauma patients often present high risk of bleeding. 

Experts are divided on the role of prophylactic inferior vena cava filters to prevent pulmonary embolism. This meta-analysis included all trials comparing the effectiveness of prophylactic vena cava filters in trauma patients vs. standard therapy, in trauma patients (vein compression devices in addition to low molecular weight sub cutaneous heparin).

8 control studies, analyzing fatal and no fatal PE rates and all-cause mortality, were included:  1064 patients in all (n = 334 with filter and n=730 with standard therapy). Evidence showed a consistent reduction of global PE (RR, 0.20, IC 95% 0.06 to 0.70) and fatal PE (RR 0.09, IC 95% 0.01 a 0.81) with no significant heterogeneity between the different studies.

No differences were observed in the incidence of deep vein thrombosis (RR 1.76, IC 95% 0.5 to 6.19) or all-cause mortality (RR 0.7, IC 95% 0.4 a 1.23).

Conclusion

Although evidence is not strong, statistics support the association between vena cava filter implantation and a lower incidence of pulmonary embolism in trauma patients. 

Editorial Comment

Assuming a baseline 1.15% PE RR in a trauma patient, the number needed to treat (NNT) to present an additional PE with vena cava filter placement is 109, and 1099 to prevent a fatal PE, which calls for especially designed studies in order to be able to select those patients that will benefit more from this technique. 

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