Systemic artery--pulmonary artery communication in Takayasu's arteritis.

Four cases of Takayasu's arteritis in which systemic artery-pulmonary artery communication is demonstrated on thoracic aortography are presented. Pulmonary arterial involvement in Takayasu's arteritis seems to be more frequent than generally appreciated (12% in the present series). Demonstration of the communication in the absence of evidence of other causes of a shunt is strongly suggestive of pulmonary artery involvement. It is not necessary to perform pulmonary angiography to confirm the involvement unless clinically indicated. It is also stressed that the presence of pulmonary artery involvement is useful to differentiate Takayasy's arteritis from arteriosclerosis.