Study of portacaval shunt effectiveness in rats

Background/Aims : This is a report of a study designed to confirm the presence and determine the effectiveness of portacaval shunts. Material and Methods : Color Doppler ultrasonography of the portal system, as a superior diagnostic procedure, was performed in experimental animals. Results : Presence of shunt is indicated by initial loss of body mass in such animals (p<0.01) as well as by increased ammonia concentration (p<0.01). Conclusions : Surgical technique of end-to-side portacaval anastomosis, originally described in 1961 and modified in 1963, has been used as a model of hepatic insufficiency in rats. Color Doppler ultrasonography of the portal system was performed to confirm PCS efficacy. Blood flow in PCS was confirmed in all operated animals. Blood flow in the portal vein was phased and respiratory dependent, slihtly decreased. Portacaval shunt had typical mixed blood flow of turbulent character. Blood flow in VCI was increased due to PCS. No comparable data for this model in rats were available. Body mass of animals with PCS significantly decreases during the first two weeks, by 15-18% (p<0.01), to be followed by statistically significant increase (p<0.01). Ammonia concentrations, obtained at the beginning of the second postoperative week, were significantly higher than in control group, probably as a consequence ofcomplete diversion of portal blood, rich with ammonia, into systemic circulation and of decreased liver capacity for ammonia uptake.