title: Vena cava filters: tiny cages that trap blood clots.  These special filters protect against pulmonary embolism but also carry risks.
mesh_terms: D001783:Blood Flow Velocity; D004867:Equipment Design; D006801:Humans; D011655:Pulmonary Embolism / Q000517:prevention & control*; D016306:Vena Cava Filters / Q000009:adverse effects / Q000706:statistics & numerical data*; D054556:Venous Thromboembolism / Q000628:therapy*