Background: In a randomized trial in patients with proximal deep-vein thrombosis, permanent vena cava filters reduced the incidence of pulmonary embolism but increased that of deep-vein thrombosis at 2 years. An 8-year follow-up was performed to assess their very long-term effect.
Methods and results: Four hundred patients with proximal deep-vein thrombosis with or without pulmonary embolism were randomized either to receive or not receive a filter in addition to standard anticoagulant treatment for at least 3 months. Data on vital status, venous thromboembolism, and postthrombotic syndrome were obtained once a year for up to 8 years. All documented events were reviewed blindly by an independent committee. Outcome data were available in 396 patients (99%). Symptomatic pulmonary embolism occurred in 9 patients in the filter group (cumulative rate 6.2%) and 24 patients (15.1%) in the no-filter group (P=0.008). Deep-vein thrombosis occurred in 57 patients (35.7%) in the filter group and 41 (27.5%) in the no-filter group (P=0.042). Postthrombotic syndrome was observed in 109 (70.3%) and 107 (69.7%) patients in the filter and no-filter groups, respectively. At 8 years, 201 (50.3%) patients had died (103 and 98 patients in the filter and no-filter groups, respectively).
Conclusions: At 8 years, vena cava filters reduced the risk of pulmonary embolism but increased that of deep-vein thrombosis and had no effect on survival. Although their use may be beneficial in patients at high risk of pulmonary embolism, systematic use in the general population with venous thromboembolism is not recommended.