- Hyperammonemia with or without ascites with normal synthetic liver functions after liver transplantation might indicate the presence of anastomotic stenosis of the portal or hepatic vein or the existence of a patent portosystemic shunt. The authors describe six patients, three children after split-liver transplantation and three adults after cadaver liver transplantation, who presented with hyperammonemia. Three patients had ascites. All lesions were successfully treated percutaneously; stents were placed in patients with anastomotic stenoses and coil embolization was performed in patients with patent portosystemic shunts--with either transhepatic or transjugular approaches according to the site of the abnormality. Ammonia levels returned to normal, and ascites had regressed completely for at least 3 months.