Harvard Heart Letter

Vena cava filters: Tiny cages that trap blood clots

These special filters protect against pulmonary embolism but also carry risks.

A common complication after surgery, trauma, or a prolonged period of bed rest is the formation of a blood clot in a vein deep inside the legs. Doctors call this a deep vein thrombosis, or DVT. If the clot breaks free of the vessel wall, it can travel through the bloodstream and lodge in a lung artery, causing a catastrophic stoppage of blood flow. This consequence, known as a pulmonary embolism, can be deadly.

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