Observations on the rare association between portal and pulmonary hypertension.

Abstract

Pulmonary arterial hypertension with severe pulmonary vascular disease is a rare association of portal hypertension in man, be it the result of cirrhosis of the liver or obstruction of the portal vein. Portal hypertension was was induced in 23 rats by partially ligating the portal vein or by totally occluding it in 2 stages. The rats were killed between 2 and 15 mo. after operation. A collateral circulation of varicose, anastomotic vessels was established, and in 6 animals well-marked esophageal varices developed. Despite this evidence of sustained portal hypertension, hypertrophy did not develop in the right ventricle or in the media of the pulmonary trunk or muscular pulmonary arteries in any of the animals. Apparently, mechanical obstruction of the portal vein per se is not responsible for the development of pulmonary hypertension. Other unidentified factors, perhaps of a humoral nature, appear to be required to induce this rare association of portal hypertension. In particular, blood levels of estrogen were not raised after ligation of the portal vein.