Cerebrovascular accident after Greenfield filter placement for paradoxical embolism.

A 69-year-old man with paradoxical embolism suffered a cerebral embolism despite treatment with anticoagulants and placement of a Greenfield filter. The open architecture of the filter allows it to maintain caval patency better than other mechanical devices, but this design also permits passage of emboli up to 3 mm in diameter. Although such small emboli do not produce symptoms in the pulmonary circuit, they can be devastating in the cerebral circulation. For this reason, the Greenfield filter may be inadequate treatment for paradoxical embolism. Ligation of the inferior vena cava is proposed as an alternative that provides better protection against small emboli.