Doppler Ultrasound and Transient Elastography in Liver Transplant Patients for Noninvasive Evaluation of Liver Fibrosis in Comparison with Histology: A Prospective Observational Study

Abstract

Background and aim: Accurate quantification of progressive liver disease is essential for therapeutic decisions and follow-up for patients who underwent liver transplantation. To evaluate the quality of noninvasive assessment of liver fibrosis in these patients, we compared Doppler ultrasound of the hepatic blood vessels as well as transient elastography (TE, FibroScan(®)) with liver biopsy following transplantation.

Methods: We performed Doppler ultrasound of the hepatic veins, hepatic artery, and portal vein as well as a TE in 48 patients who underwent liver transplantation 12 months ago. Hepatic venous flow was evaluated by determination of the resistance index (HVRI) of the right hepatic vein. Doppler and TE results were compared with histopathologic workup of a 12-month protocol liver biopsy after transplantation.

Results: HVRI showed a high reliability in predicting liver fibrosis stage FII or higher (AUROC of 0.99 ± 0.001 for FII or higher, the HVRI < 1.05 with a sensitivity and specificity of 100 and 91.43 %) compared to histopathologic workup (Desmet's score) and was comparable to TE analysis. Both HVRI and TE differed significantly in no or minimal fibrosis versus FII or higher (p < 0.001). In contrast, portal vein and hepatic artery did not show significant changes in blood flow in our study population.

Conclusions: Hepatic vein flow resistance index is a valuable tool in noninvasive evaluation of liver fibrosis in liver transplantation follow-up predicting FII or higher and might help reducing the number of protocol biopsies needed.