Cyclosporin A Negatively Effects the Hepatic Extraction Fraction of Hepatobiliary Scintigraphy in Liver Transplant Recipients.

Abstract

Aim of the study Hepatobiliary scintigraphy can detect post-liver transplantation (LTx) structural complications and provide information of graft function. Hepatic extraction fraction (HEF) is a measurement of the hepatic extraction efficiency and hepatic extraction rate. In this study, we compared the HEF with biochemical and histological parameters between the LTx patients receiving cyclosporin A (CSA) or tacrolimus (TAC). Methods Thirty-nine adult patients who underwent LTx due to HCV cirrhosis between March 2007 and May 2011 were evaluated. All patients underwent a three-month follow-up that included hepatobiliary scintigraphy and blood biochemistry tests (s-bilirubin, ALT, AST, ALP, and gamma-GT). The same tests were repeated at the one-year follow-up; in addition s-creatinine, Iohexol clearance and a liver biopsy were performed. These clinical parameters were compared between the two groups, TAC (n=15), and CSA (n=24). Results The average HEF was significantly lower in the CSA group compared to the TAC group both at 3-month and 1-year after transplantation (p<0.001). The liver biochemistry tests, average donor and recipient age, average cold ischemia time, and Iohexol clearance were comparable between the two groups. Histology showed that the TAC group had more inflammation than the CSA group. Moreover, three patients who converted from CSA to TAC for liver unrelated side effects between 3.7 and 6.3 months postoperatively all increased their HEF values (27 to 90%, 42 to 100%, and 13 to 26%). Conclusion CSA treated patients presented a lower HEF value on hepatobiliary scintigraphy in spite of comparable liver function by traditional measurements indicating a false decrease on HEF values by CSA. Our finding has significant clinical implications as it indicates that the assessment of the liver graft function may be misled due to the falsely low HEF values in CSA treated patients with otherwise good liver function.