Porto-hepatic bypass by organohepatopexy in rats with prehepatic portal hypertension. Formation of new venous porto-hepatic collaterals following omento-, jejuno-, and splenohepatopexy, and their effect on portal vein pressure.

Transposition to the liver of the greater omentum; the jejunum, and the spleen in 3 groups of rats with prehepatic portal hypertension due to a calibrated portal vein stenosis with a diameter of 1.2 mm resulted in the formation of new venous collaterals from the transposed organs into the liver parenchyma. The collaterals were visualized macro- and microscopically, as well as angiographically, and were found to drain into intrahepatic branches of the portal vein, sinusoids, and hepatic veins. The portal vein pressure 8 weeks after stenosis and transposition was found to be significantly lower in rats with transposed organs than in controls. The collaterals were sufficiently well developed to significantly reduce the increase in portal vein pressure that follows acute occlusion of the portal vein and the natural splenorenal collaterals.