Effects of Pneumonectomy on Pulmonary Circulation in Adult and Young Animals

Abstract

Serial observations were made on the changes in pulmonary-artery pressure, radiological, and histological features of the pulmonary vasculature after pneiunonectomy or ligation of a single pulmonary artery in adult dogs and in puppies. Acute occlusion produced only insignificant changes in the pulmonary-arterial pressure. After one to two days, a rapid rise in pulmonary-arterial pres sure was observed. The pressure then gradually rose and in the subsequent months reached somewhat higher levels in the puppies as compared with the adult dogs. A decrease in pulmonary-arterial pressure which occurred after the initial rise in pressure was noted in one adult dog and two puppies. Comparison of the histology of the remaining lung with the control lung showed the development of medial hypertrophy of the smaller and medium-sized vessels, with an increase in the wall to lumen ratio. No significant difference was noted between the histological features of the adult and young animals. Pulmonary arteriograrns revealed progressive dilatation and tortuosity of the main pulmonary artery and its major branches, less striking in the puppies as compared with the adult dogs.