Inferior vena cava (IVC) filters appear to reduce the risk of subsequent pulmonary embolism, increase the risk for deep vein thrombosis and have no significant effect on overall mortality, according to research published Sept. 18 in the Journal of the American College of Cardiology.

In this systematic review and meta-analysis Behnood Bikdeli, MD, et al., examined 11 studies with a total of 4,204 patients on the efficacy and safety of IVC filters. Use of IVC filters was associated with a reduced risk of subsequent pulmonary embolism (odds ratio [OR], 0.50; 95 percent confidence interval [CI], 0.33-0.75). Mortality related to pulmonary embolism was nonsignificantly lower in patients who had an IVC filter compared with controls (OR, 0.51; 95 percent CI, 0.25-1.05). Use of IVC filters was not associated with a significant change in all-cause mortality (OR, 0.91; 95 percent CI, 0.70-1.19). Compared with controls, patients receiving an IVC filter had an increased risk of subsequent deep vein thrombosis (OR, 1.70; 95 percent CI, 1.17-2.48).

The five randomized controlled trials (RCTs) included in the meta-analysis all had limitations in methodology and in outcomes assessment. All were open label, and blinded outcome assessment was reported in only one trial. One study had a high risk of bias for lack of random sequence generation. Confidence in the outcomes estimates derived from pooled data from the RCTs for all outcomes was low.

The authors acknowledge that the small number of studies and patients included is a limitation of their analysis. They hope that this study will lead to larger prospective controlled studies to better inform the evidence base across clinical scenarios. Until then, practitioners should be mindful about indiscriminate use of IVC filters.

In an accompanying editorial comment, Stavros V. Konstantinides, MD, PhD, writes that this study, "reminds us to avoid the indiscriminate use of filters (as well as any other interventions) in patients for whom excellent medical therapy is available. It also highlights the importance of documenting, in prospective cohort studies fulfilling high methodological standards to exclude selection and reporting bias, the characteristics and the outcomes of patients receiving inferior vena cava filters for prevention of pulmonary embolism."

Keywords: Vena Cava Filters, Odds Ratio, Prospective Studies, Confidence Intervals, Vena Cava, Inferior, Pulmonary Embolism, Venous Thrombosis, Risk, Outcome Assessment, Health Care

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