Detection of graft fibrosis by vibration‐controlled transient elastography in pediatric liver transplant recipients

Abstract

Pediatric liver transplant recipients are at risk of developing graft fibrosis which can affect patient survival. VCTE is a non‐invasive tool that measures LSM and has been shown to correlate with hepatic fibrosis. The aim of this study was to therefore evaluate the ability of LSM to predict fibrosis in pediatric liver transplant recipients with different graft types. We performed a cross‐sectional study evaluating LSM of 28 pediatric liver transplant recipients who underwent a total of 20 liver biopsies within 1 month of LSM. LSM was compared to liver histology as well as graft type: WL or PL. The median LSM of all post‐transplant patients was 5.6 kPa (range = 2.7‐18.3). There was a statistically significant correlation between LSM and METAVIR fibrosis score (P = .001) and LAF score (P < .001). There was no difference in LSM between graft type (P = .088). The AUROC curve for LSM predicting any significant fibrosis (F ≥ 2) was 0.863. A cutoff value of 7.25 had a sensitivity of 71%, specificity of 100%, NPV of 87%, and PPV of 100% for significant fibrosis. LSM by VCTE is feasible in pediatric liver transplant recipients regardless of graft type. We found a significant correlation between LSM and hepatic fibrosis and established a cutoff value that may help determine which patients warrant further evaluation for graft fibrosis.

Diagnostic performance of 2D‐shear wave elastography and serum fibrosis markers for evaluation of hepatic graft fibrosis in pediatric liver‐inclusive transplant recipients: A prospective pilot study

“…Nevertheless, 2D-SWE was able to distinguish children with significant hepatic graft fibrosis (≥F2) from those with no-mild fibrosis (F0-F1) with a good AUROC of 0.80, and its diagnostic performance further improved when combined with serum markers APRI and/or FIB4. The LS cut-off value of 1.2 m/s (4.2 kPa) was lower than that reported in previous studies that used TE (6.5-7.25 kPa) 28,34 or point-SWE (1.5-1.57 m/s) 25,27,28,34 ; therefore, strategies to combine LS measurement with other markers might help boost the PPV. Furthermore, a specific LS cut-off should be determined based on the context in which the elastography technique is intended to be used, taking into account the false positive and false negative rates.…”

“…Nevertheless, 2D‐SWE was able to distinguish children with significant hepatic graft fibrosis (≥F2) from those with no‐mild fibrosis (F0‐F1) with a good AUROC of 0.80, and its diagnostic performance further improved when combined with serum markers APRI and/or FIB4. The LS cut‐off value of 1.2 m/s (4.2 kPa) was lower than that reported in previous studies that used TE (6.5–7.25 kPa) 28,34 or point‐SWE (1.5–1.57 m/s) 18,27 to detect significant fibrosis in LT children. Notably, the reference values for normal LS reportedly vary by elastography techniques as well as patient populations.…”

“…The prevalence of significant hepatic graft fibrosis in the current cohort (18.2%) was lower than in previous studies that examined noninvasive tests in LT children using liver biopsy as the reference (ranging from 20% to 38%). 12,24,27,28,34 All pediatric studies, including the present study, have a different distribution of various fibrosis stages and a relatively low number of children with significant hepatic graft fibrosis (≥F2) and advanced hepatic graft fibrosis (≥F3).…”

“…Additionally, although liver biopsy is used as the reference test, its accuracy is limited by intra-observer and/or interobserver variation and sampling error that may result in under-or overestimation of fibrosis stages. [7][8][9] Given the small sample size, we were unable to re- 12,25,28,34 we performed liver biopsy only for clinical indications, at the time when all patients had elevated transaminases; therefore, the reliability and usefulness of these serum markers in the pediatric LT population warrant further validation in a future study of protocol liver biopsies.…”

“…Whether the normal LS range obtained by 2D‐SWE in LT children differs from that in healthy children warrants further investigation with a larger cohort that includes a control group of healthy children in addition to LT children. Moreover, a common limitation of elastography techniques across pediatric studies has been a high NPV but a lower PPV 25,27,28,34 ; therefore, strategies to combine LS measurement with other markers might help boost the PPV. Furthermore, a specific LS cut‐off should be determined based on the context in which the elastography technique is intended to be used, taking into account the false positive and false negative rates.…”