[Pulmonary vascular changes after portasystemic shunt operation in rats].

The prevalence of pulmonary hypertension among patients with portal hypertension, especially following a shunt operation, is significantly higher than that of primary pulmonary hypertension, suggesting the hypothesis that large portasystemic shunt plays a major role in development of pulmonary hypertension. To support this hypothesis, I studied experimentally the hemodynamic changes and the pathological findings in lung in 97 rats killed between one and 24 months after portasystemic shunt operations. The right ventricular systolic pressure (RVSP) and the right ventricular wall thickness were significantly high in the 82 rats raised over 3 months after the operations. In these rats the pathological findings in the lung revealed a thickness of pulmonary arterioles with medial hypertrophy, concentric intimal proliferation, and plexiform lesions. The values of endotoxin in central venous blood were significantly high and related with RVSP and shunt ratio. In pulmonary venous blood, thromboxane B2 increased and 6-keto PGF1a decreased. In conclusion, some of the rats developed pulmonary hypertension fter receiving a portasystemic shunt operation. It is suspected that endotoxin passing through the shunt plays a role in the development of pulmonary hypertension.