Experimental prehepatic portal hypertension and esophageal varices in the rabbit.

Prehepatic portal hypertension was induced in rabbits by constricting the vein, creating a pressure approximately 100% higher than the preoperative value. Angiographic, endoscopic, and pressure studies confirmed the portal hypertension to be decompressed, with shunting of blood through esophageal varices. Small periportal collaterals were insufficient to prevent the esophageal shunting. The esophageal varices developed within 4 weeks and were a consistent finding throughout the observation period. No relation between the extent of portal hypertension and the size of the varices was found.