A vena cava filter is an umbrella-shaped barrier device that is inserted into the large vein that returns blood to the heart from the abdomen and legs (inferior vena cava). This filter may help prevent blood clots that form in the deep veins of the lower limbs from traveling to the lungs, where they may block blood flow.
Vena cava filters are inserted into the vena cava using a catheter inserted through a vein in the neck or groin.