Cumulative percentage of patients suffering a symptomatic pulmonary embolism at 3, 12, and 24 months of follow-up.

Vena caval filters do not provide significantly greater protection against PE than anticoagulation alone. Decousus et al randomized 400 patients to receive a vena caval filter with anticoagulation or anticoagulation alone. Filters significantly reduced the incidence of PE at 8 to 12 days (P = .03). This protection was no longer significant after 2 years of follow-up (P = .16). Data adapted from Decousus et al.105