"Efficacy of Vena Caval Filters in Preventing Pulmonary Embolism in Patients with Deep-Vein Thrombosis".The New England Journal of Medicine. Date published.
Links to original sources: Wiki Journal Post Full Journal Article
Do vena caval filters, in addition to heparin therapy, reduce the incidence of pulmonary embolism in high-risk patients with proximal deep-vein thrombosis?
In high-risk patients with proximal deep-vein thrombosis, vena caval filters initially reduced the incidence of pulmonary embolism but were associated with an increased incidence of recurrent deep-vein thrombosis and did not affect long-term mortality. Low-molecular-weight heparin was found to be as effective and safe as unfractionated heparin for preventing pulmonary embolism in these patients.
Vena caval filters have been used as a method to reduce pulmonary embolism risk in patients with deep-vein thrombosis. However, their overall efficacy and safety had not been rigorously evaluated in randomized trials. This study found that, while the initial placement of a permanent filter reduced early pulmonary embolism events, it did not affect mortality and led to a higher rate of long-term deep-vein thrombosis.
This study suggests that the use of vena caval filters should not be systematic in high-risk patients with proximal deep-vein thrombosis who are receiving anticoagulants. The study also supports the use of low-molecular-weight heparin as an effective and safe alternative to unfractionated heparin in this patient population.
Multicenter, randomized, open trial with a two-by-two factorial design. N=400 patients were randomized to either receive a vena caval filter or no filter, and to either receive low-molecular-weight heparin (enoxaparin) or unfractionated heparin. Patients were followed for two years for rates of venous thromboembolism, death, and major bleeding events.
Hospitalized patients over 18 years of age with acute proximal deep-vein thrombosis confirmed by venography, considered at high risk for pulmonary embolism. Patients were excluded for several reasons, including previous filter placement, contraindications to anticoagulants, and life expectancy concerns among others.
Patients were assigned to receive one of four types of permanent vena caval filters or no filter. Assignment to low-molecular-weight heparin involved weight-adjusted dose subcutaneous enoxaparin every 12 hours for 8-12 days, while the unfractionated heparin group received intravenous heparin adjusted according to activated partial-thromboplastin time for the same duration.
Primary Outcome: Incidence of symptomatic or asymptomatic pulmonary embolism at day 12. Secondary Outcomes: Rates of symptomatic pulmonary embolism, recurrent deep-vein thrombosis, death, major filter complications, and major bleeding over two years.
The study was terminated early due to slow recruitment, which may have affected the ability to detect smaller differences in outcomes. Additionally, systematic detection of asymptomatic pulmonary embolism between days 8-12 was not completed for a subset of patients.
Funded by Bellon Rhône–Poulenc Rorer Laboratories, with cosponsors including Ministère Français de la Santé, Caisse Nationale d'Assurance Maladie, and others.
Refer to the original publication in NEJM.