Noninvasive Diagnostic Methods for the Assessment of Hepatic Fibrosis in Liver Transplant Recipients

Abstract

Hepatic fibrosis in liver transplant recipients is the main predictive factor for graft function. Diagnostic methods for hepatic fibrosis staging should be available, reproducible, and noninvasive, if possible. We aimed to compare diagnostic methods for the assessment of hepatic fibrosis in transplant recipients: liver biopsy as a reference method, dynamic elastography, and direct and indirect blood markers (the ELF test [Enhanced Liver Fibrosis] test and the FibroTest). We sought to set a cutoff value for each method in order to assess significant liver fibrosis (F ≥2). The study involved 62 patients after liver transplantation. Fibrosis was assessed in biopsy specimens using the METAVIR Score System (F0-F4). To identify clinically significant cutoff values of hepatic fibrosis (F ≥2, F ≥3, F=4) for each method compared, a receiver-operating characteristic (ROC) curve analysis was used. Area under ROC for the prediction of significant fibrosis (F ≥2), advanced fibrosis (F ≥3), and cirrhosis (F=4) for the study group was 0.5938, 0.8952, and 0.9583 for dynamic elastography; 0.7295, 0.7072, and 0.8409 for the ELF test; and 0.4863, 0.8049, and 0.8723 for the FibroTest. The cutoff value for F ≥2 for dynamic elastography was 4.65 kPa; for the ELF test, 9.27; and for the FibroTest, 0.72. The sensitivity and specificity of the tests studied, as compared with biopsy results, increase with increasing severity of hepatic fibrosis. The noninvasive diagnostic methods are of limited value in the diagnosis of early fibrosis stages. In the diagnostic assessment of hepatic fibrosis in its advanced stages, dynamic elastography can be used in conjunction with ELF test as a noninvasive alternative to liver biopsy.