To prevent pulmonary embolism, doctors usually use medications that limit blood clotting. However, for some people, doctors may recommend that an inferior vena cava (IVC) filter be temporarily or permanently placed in the inferior vena cava. This filter device typically is recommended when medications that limit clotting cannot be used, for example, when a person is also having bleeding. The filter can trap emboli before they reach the heart but allow blood to flow through freely. Emboli that are trapped sometimes dissolve on their own.