Diagnostic performance of non-invasive tests for evaluation of hepatic graft fibrosis in pediatric liver transplantation: A scoping review

Background: Hepatic graft fibrosis is a common histologic finding of pediatric liver transplant (LT) that might affect long-term graft outcome. However, its diagnosis and staging require an invasive liver biopsy.

Aim: To review the published literature on the diagnostic accuracy of elastography and serum-based fibrosis markers for assessing hepatic graft fibrosis in pediatric LT recipients.

Methods: A scoping review was conducted using a systematic search of published literature in PubMed (MEDLINE), EMBASE, SCOPUS, and Cochrane Library between 2002 and 2019. We included all English conference abstracts or full-text articles that examined the diagnostic accuracy of the non-invasive test(s) to assess hepatic fibrosis in LT children, using liver biopsy as the reference test.

Results: Eight studies were included, of which 6 examined transient elastography (TE), one investigated acoustic radiation force impulse elastography, and 5 examined serum-based fibrosis markers (AST/ALT ratio, AST-to-platelet ratio index, FibroTest, enhanced liver fibrosis test). TE reportedly had a good AUROC (range: 0.82-0.92) to distinguish children with hepatic graft fibrosis (≥F1) from those with no fibrosis. However, there was considerable overlap of liver stiffness cutoffs in the mild to significant fibrosis groups (≥F1 and ≥F2). Current serum-based fibrosis markers reportedly had an unsatisfactory diagnostic accuracy.

Conclusions: TE in LT children has similar diagnostic value and limitations as in the non-transplant setting. Prospective studies are warranted to validate an optimal liver stiffness cutoff for predicting significant hepatic graft fibrosis (≥F2) and to determine if a meaningful change in liver stiffness from baseline could identify patients at risk for fibrosis progression.