An attempt to induce portal hypertension and esophageal varices in the rat.

An attempt to induce portal hypertension using Ameroid constrictors and shunt operations is described. 1 week after the application of the Ameroid constrictor around the portal trunk, it was completely occluded and portal venous pressure was elevated to a level about twice of normal range. Angiographically, splenorenal collaterals and collaterals overbridging the Ameroid constrictor were observed in all examined rats. However, esophageal varices could not be found in any rat. In the second series of the experiment, an end-to-side cavoportal shunt was created before the application of the Ameroid constrictor. This operation model was devised to increase the portal venous flow. At the same time this operation should inhibit the development of splenorenal collaterals and as expected collaterals to the superior vena cava system developed instead. However, they were not located in the esophageal wall but retroperitoneally.