Pathological features of the pulmonary artery in Takayasu arteritis.

Little attention has been paid to the pathological features of the pulmonary artery in Takayasu arteritis. Autopsy specimens of 6 cases of this disease were studied. Lesions were found in the aortic arch and its brachiocephalic branches in all cases and in both the aortic arch and thoracoabdominal aorta in 5 cases. The pathohistologic characters of the pulmonary artery were very similar to those of the systemic artery. Stenosis-recanalization, so-called blood vessels-in-blood vessels, of the pulmonary elastic arteries were found in four cases. These lesions were not observed in the systemic arteries, and most of the newly formed channels in them seemed to be branches of bronchial arteries. Luminal obstruction of pulmonary muscular arteries was observed in 4 cases, cellular arteritis of muscular arteries in 2 cases, and angiomatoid dilatation of small blood vessels in 2 cases. Thus in this study we found peculiar stenosis-recanalization lesions of the pulmonary elastic arteries, and also showed that the pulmonary elastic and muscular arteries are frequently involved in Takayasu arteritis. These findings suggest that pulmonary hypertension could influence morbidity and long-term mortality in this disease.