An animal study of portal hypertension

For the purpose of elucidation the mechanism of portal venous resistance and portal venous blood flow in maintaining an elevated portal hypertension. The splanchnic and systemic hemodynamics were evaluated in portal hypertensive rat model, which is induced by partial portal vein ligation (PVL). Organ blood flow and portal-systemic shunting were measured by radio-active microsphere techniques. In this study all the PVL rats had higher mean portal venous pressure (15.2 +/- 1.6 mmHg) when compared to the Sham-operation control rats (5.3 +/- 1.2 mmHg). Furthermore, portal systemic shunting was significantly higher in the 14th day PVL rats (87.2 +/- 3.6%) than control rats (0.3 +/- 0.1%) (p less than 0.05). There was a rapid increase in portal venous inflow from the 4th day (6.1 +/- 0.8 vs 4.2 +/- 0.7 ml/min/100 gm BW, p less than 0.05) in the PVL rats than in control rats. However, the total peripheral resistance and splanchnic arterial resistance were reduced in the 14th PVL rats than control rats. The Cardiac index was much higher in the 14th PVL rats than control rats. Thus our results demonstrate that portal hypertension is maintained by a hyperdynamic portal venous inflow. This model is reproducible for us to study portal hypertension within a short period of time.