Hepatic clearance improves after angioplasty of the hepatic vein

Anastomotic stricture sometimes causes hepatic congestion leading to decreased hepatic clearance of drugs. We herein describe a correlation between trough levels of tacrolimus and an anastomotic stricture of the hepatic vein. A 13-year-old boy underwent living donor liver transplant with a left lobe graft from his mother. Outflow blockage due to an anastomotic stricture of the hepatic vein developed 3 months after transplant. His anastomotic site had been repeatedly treated with percutaneous transvenous angioplasty (PTA) by balloon dilation. About 1 year after transplant, his trough level of tacrolimus promptly decreased after balloon dilation (from 15.7 to 5.6 ng/dL). Liver function tests showed abnormalities, which were diagnosed as acute cellular rejection, and he was treated with pulse steroid therapy. The calculated half-life of tacrolimus (T1/2) showed marked improvement after PTA (from 35 to 22 hours). A 45-year-old woman underwent living donor transplantation due to alcoholic liver cirrhosis with a left lobe graft from her brother. An anastomotic stricture of the hepatic vein developed 4 months after transplant. She was treated with balloon dilation, which caused an abrupt decrease in the trough level of tacrolimus (12 to 4 ng/dL). Her alkaline phosphatase was elevated and she was diagnosed with rejection, which was treated with an increase of dosage of tacrolimus. In outflow block, the T1/2 of tacrolimus increases probably due to decreased hepatic clearance by stagnation or congestion of the liver. However, hepatic clearance of drugs quickly recovers after PTA. Close monitoring of immunosuppressive agents is fundamental at the time of angioplasty to avoid acute cellular rejection as developed in our two cases.