Isolated aortic origin of right pulmonary artery. Report of a case with special reference to pulmonary vascular disease in the left and right lungs.

Morphometric study of the pulmonary vasculature was performed on lung biopsy specimens from a one-year-old girl who underwent anatomic repair of isolated aortic origin of the right pulmonary artery. Medial hypertrophy of small pulmonary arteries in the right lung was much less remarkable than that in the left lung. In contrast, intimal lesions in the right lung were much more advanced than those in the left lung. Fully oxygenated blood in the right pulmonary artery might suppress medial hypertrophy in response to high pressure and thin media fail to protect intima from high pressure, resulting in severe intimal lesions. This situation in the right lung resembles that in complete transposition of the great arteries.