Fatal migration of vena caval filters.

Inferior vena caval filters, which are used to prevent pulmonary thromboemboli, may migrate to the right ventricle of the heart. We describe two deaths after the migration of IVC filters. In neither was the filter incorrectly inserted or deployed. In each instance, a deep pelvic/leg vein thromboembolus was associated with the dislodged filter. When a thromboembolism becomes entrapped in the filter, the surface area increases and the previous low-resistance filter becomes obstructed or partially obstructed. The force of the blood flow on this entangled wire/clot may cause the filter/clot to embolize to the heart. Even though one may be tempted to certify the death as due to the failure of the filter, death likely would have occurred if the filter were not in place. If the deep venous thrombus is caused by a disease (not an injury or other medical complication), the manner of these deaths is best certified as natural.