A canine experimental model was used to investigate the feasibility of using balloon-expandable portacaval shunts in humans with chronic portal hypertension. Intrahepatic portacaval shunts were created in nine dogs with stable portal hypertension previously induced by intraportal injections of polyvinyl alcohol (Ivalon). Embolic material was injected periodically through a subcutaneous port that allowed repeated access to the portal system. Shunts were placed 14 weeks after the last embolization. A shunt patency rate of 100% was observed up to 48 weeks. Low portacaval pressure gradient and high shunt flow accounted for the good results.