FibroScan evaluation of liver fibrosis in liver transplantation

Non-invasive evaluation of hepatic macrosteatosis in deceased donors

INTRODUCTION

Liver allocation changes have led to increased travel and expenditures, highlighting the need to efficiently identify marginal livers suitable for transplant. We evaluated the validity of existing non-invasive liver quality tests and a novel machine learning-based model at predicting deceased donor macrosteatosis >30%.

METHODS

We compared previously-validated non-invasive tests and a novel machine learning-based model to biopsies in predicting macrosteatosis >30%. We also tested them in populations enriched for macrosteatosis.

RESULTS

The Hepatic Steatosis Index area-under-the-curve (AUC) was 0.56. At the threshold identified by Youden's J statistic, sensitivity, specificity, positive, and negative predictive values were 49.6%, 58.9%, 14.0%, and 89.7%. Other tests demonstrated comparable results. Machine learning produced the highest AUC (0.71). Even in populations enriched for macrosteatosis, no test was sufficiently predictive.

CONCLUSION

Commonly used clinical scoring systems and a novel machine learning-based model were not clinically useful, highlighting the importance of pre-procurement biopsies to facilitate allocation.

Novel Noninvasive Biomarkers in Liver Transplantation: A Tool on the Doorstep of Clinical Utilization

Biomarkers have the potential to transform the detection, treatment, and outcomes of liver transplant complications, though their application is limited because of the lack of prospective validation. Although many genetic, proteomic, and immune markers correlating with allograft rejection and graft dysfunction have been described, evaluation of these markers in combination and validation among a broad liver transplant recipient population remain understudied. In this review, we present evidence supporting biomarker applications in 5 clinical liver transplant scenarios: (i) diagnosis of allograft rejection, (ii) prediction of allograft rejection, (iii) minimization of immunosuppression, (iv) detection of fibrosis and recurrent disease, and (v) prediction of renal recovery following liver transplantation. Current limitations for biomarker utilization and opportunities for further investigation are discussed. Accurate risk assessment, diagnosis, and evaluation of treatment responses using such noninvasive tools will pave the way for a more personalized and precise approach to management of the liver transplant patients that has profound potential to reduce morbidity and improve graft and patient longevity.

Clinical implications of serum autotoxin in regular follow up after pediatric living donor liver transplantation for biliary atresia

BACKGROUND

Pediatric patients sometimes develop graft fibrosis after living donor liver transplant (LDLT). Autotaxin is a recently developed serum marker for hepatic fibrosis. We studied the relationship between serum autotaxin levels and histological findings in patients after LDLT for biliary atresia (BA).

METHODS

Information on patients aged <19 years who received LDLT for BA and were followed for at least 1 year after LDLT was gathered. Autotaxin levels were compared with pathological fibrosis scores.

RESULTS

The study included 52 patients, of whom 4 patients had no fibrosis (F0), 36 patients had F1 fibrosis, and 12 patients had F2. The median serum autotaxin level was 0.89 mg/L. In patients with portal vein (PV) complications such as stenosis or thrombosis (n = 7), the mean autotoxin level was 1.25 mg/L compared with 0.95 mg/L in patients without PV complications (p = 0.004). Among patients without PV complications, the mean autotaxin level was 0.90, 0.88, and 1.18 mg/L in F0, F1, and F2 fibrosis, respectively. The mean autotaxin was higher in F2 fibrosis than in F0 or F1 fibrosis (p<0.05). Autotoxin had a high area under the curve (0.86) with the cut-off level of 0.897 mg/L.

CONCLUSION

Serum autotaxin is a novel marker for liver fibrosis in patients after pediatric LDLT for BA.

TYPE OF STUDY

Study of Diagnostic Test.

LEVEL OF EVIDENCE

Level II.

Serum markers of type III and IV procollagen processing predict recurrence of fibrosis in liver transplanted patients

Following liver transplantation (LT), 10–30% of patients develop recurrent cirrhosis (RC). There is an urgent need for predictive non-invasive markers for improved monitoring of these patients. Here we studied extracellular matrix biomarkers as predictors of RC after LT. Forty-seven LT patients were divided into groups of fast, intermediate or non-progressors towards RC (<1 year, 3–5 years or no advanced fibrosis >5 years after LT), assessed by follow-up liver biopsies. Markers of interstitial matrix type III and V collagen formation (PRO-C3 and PRO-C5), basement membrane type IV collagen formation (PRO-C4) and degradation (C4M) were assessed in serum samples collected 3, 6 and 12 months post-LT using specific ELISAs. PRO-C3, PRO-C4, and C4M were elevated in fast progressors compared to non-progressors 3 months after LT. C4M and PRO-C4 additionally differentiated between intermediate and fast progressors at 3 months. PRO-C3 was best predictor of survival, with LT patients in the highest PRO-C3 tertile having significantly shorter survival time. This shows that interstitial matrix and basement membrane remodeling in RC may be distinguishable. Markers originating from different sites in the extracellular matrix could be valuable tools for a more dynamic monitoring of patients at risk of RC. However, this needs validation in larger cohorts.

Usefulness of Transient Elastography for Non-Invasive Diagnosis of Liver Fibrosis in Pediatric Non-Alcoholic Steatohepatitis

BACKGROUND

Transient elastography (FibroScan®) is a non-invasive and rapid method for assessing liver fibrosis. While the feasibility and usefulness of FibroScan® have been proven in adults, few studies have focused on pediatric populations. We aimed to determine the feasibility and usefulness of FibroScan® in Korean children.

METHODS

FibroScan® examinations were performed in 106 children (age, 5-15 years) who visited the Konyang University Hospital between June and September 2018. Liver steatosis was measured in terms of the controlled attenuation parameter (CAP), while hepatic fibrosis was evaluated in terms of the liver stiffness measurement (LSM). Children were stratified into obese and non-obese controls, according to body mass index (≥ or < 95th percentile, respectively).

RESULTS

The obese group was characterized by significantly higher levels of aspartate aminotransferase (AST, 57.00 ± 48.47 vs. 26.40 ± 11.80 IU/L; P < 0.001) and alanine aminotransferase (ALT, 91.27 ± 97.67 vs. 16.28 ± 9.78 IU/L; P < 0.001), frequency of hypertension and abdominal obesity (abdominal circumference > 95% percentile) (P < 0.001), CAP (244.4-340.98 dB/m), and LSM (3.85-7.77 kPa) (P < 0.001). On FibroScan®, 30 of 59 obese children had fibrosis (LSM > 5.5 kPa), whereas the remaining 29 did not (LSM < 5.5 kPa). Obese children with fibrosis had higher levels of AST (73.57 ± 56.00 vs. 39.86 ± 31.93 IU/L; P = 0.009), ALT (132.47 ± 113.88 vs. 48.66 ± 51.29 IU/L; P = 0.001), and gamma-glutamyl transferase (106.67 ± 69.31 vs. 28.80 ± 24.26 IU/L; P = 0.042) compared to obese children without fibrosis. LSM had high and significant correlation (P < 0.05) with AST, ALT, homeostasis model assessment for insulin resistance, and AST-to-platelet ratio index.

CONCLUSION

FibroScan® is clinically feasible and facilitates non-invasive, rapid, reproducible, and reliable detection of hepatic steatosis and liver fibrosis in the Korean pediatric population.

Transient elastography for non-invasive evaluation of post-transplant liver graft fibrosis in children

As graft survival in pediatric LT is often affected by progressive fibrosis, numerous centers carry out protocol liver biopsies. Follow-up biopsy protocols differ from center to center, but all biopsies are progressively spaced out, as time from transplant increases. Therefore, there is a need for non-invasive techniques to evaluate graft fibrosis progression in those children who have no clinical or serological signs of liver damage. Indirect markers, such as the APRI, should be relied on with caution because their sensitivity in predicting fibrosis can be strongly influenced by the etiology of liver disease, severity of fibrosis, and patient age. A valid alternative could be TE, a non-invasive technique already validated in adults, which estimates the stiffness of the cylindrical volume of liver tissue, 100-fold the size of a standard needle biopsy sample. The aims of this study were to evaluate the reliability of TE in children after LT and to compare both the TE and the APRI index results with the histological scores of fibrosis on liver biopsies. A total of 36 pediatric LT recipients were studied. All patients underwent both TE and biopsy within a year (median interval -0.012 months) at an interval from LT of 0.36 to 19.47 years (median 3.02 years). Fibrosis was assessed on the biopsy specimens at histology and staged according to METAVIR. There was a statistically significant correlation between TE stiffness values and METAVIR scores (P = .005). The diagnostic accuracy of TE for the diagnosis of significant fibrosis (F ≥ 2) was measured as the area under the curve (AUROC = 0.865), and it demonstrated that the method had a good diagnostic performance. APRI was not so accurate in assessing graft fibrosis when compared to METAVIR (AUROC = 0.592). A liver stiffness cutoff value of 5.6 kPa at TE was identified as the best predictor for a significant graft fibrosis (METAVIR F ≥ 2) on liver biopsy, with a 75% sensitivity, a 95.8% specificity, a 90% positive predictive value, and an 88.5% negative predictive value. These data suggest that TE may represent a non-invasive, reliable tool for the assessment of graft fibrosis in the follow-up of LT children, alerting the clinicians to the indication for a liver biopsy, with the aim of reducing the number of protocol liver biopsies.

Diagnosis and Evaluation of Nonalcoholic Fatty Liver Disease/Nonalcoholic Steatohepatitis, Including Noninvasive Biomarkers and Transient Elastography

The incidence and prevalence of nonalcoholic fatty liver disease (NAFLD) are increasing and identification of people at risk of disease progression is extremely important. The current gold standard for diagnosing NAFLD/nonalcoholic steatohepatitis (NASH) is by liver biopsy, but it has several limitations. Noninvasive tests via biomarkers and transient elastography to assess NAFLD/NASH are being used in clinical practice. The most validated diagnostic panels include the NAFLD fibrosis score, FIB-4 (Fibrosis-4), and FibroMeter. Transient elastography is very useful in evaluating advanced fibrosis and cirrhosis.

Controlled Attenuation Parameter and Liver Stiffness Measurements for Steatosis Assessment in the Liver Transplant of Brain Dead Donors

BACKGROUND

One of the main selection criteria of the quality of a liver graft is the degree of steatosis, which will determine the success of the transplantation. The aim of this study was to evaluate the ability of FibroScan and its related methods Controlled Attenuation Parameter and Liver Stiffness to assess objectively steatosis and fibrosis in livers from brain-dead donors to be potentially used for transplantation.

METHODS

Over a period of 10 months, 23 consecutive brain dead donors screened for liver procurement underwent a FibroScan and a liver biopsy.

RESULTS

The different predictive models of liver retrievability using liver biopsy as the gold standard have led to the following area under receiver operating characteristic curve: 76.6% (95% confidence intervals [95% CIs], 48.2%-100%) when based solely on controlled attenuation parameter, 75.0% (95% CIs, 34.3%-100%) when based solely on liver stiffness, and 96.7% (95% CIs, 88.7%-100%) when based on combined indices.

CONCLUSIONS

Our study suggests that a preoperative selection of brain-dead donors based on a combination of both Controlled Attenuation Parameter and Liver Stiffness obtained with FibroScan could result in a good preoperative prediction of the histological status and degree of steatosis of a potential liver graft.

Transient Elastography-Based Liver Profiles in a Hospital-Based Pediatric Population in Japan

Background & Aims

The utility of transient elastography (FibroScan) is well studied in adults but not in children. We sought to assess the feasibility of performing FibroScans and the characteristics of FibroScan-based liver profiles in Japanese obese and non-obese children.

Methods

FibroScan examinations were performed in pediatric patients (age, 1–18 yr) who visited Osaka City University Hospital. Liver steatosis measured by controlled attenuation parameter (CAP), and hepatic fibrosis evaluated as the liver stiffness measurement (LSM), were compared among obese subjects (BMI percentile ≥90%), non-obese healthy controls, and non-obese patients with liver disease.

Results

Among 214 children examined, FibroScans were performed successfully in 201 children (93.9%; median, 11.5 yr; range, 1.3–17.6 yr; 115 male). CAP values (mean±SD) were higher in the obese group (n = 52, 285±60 dB/m) compared with the liver disease (n = 40, 202±62, P<0.001) and the control (n = 107, 179±41, P<0.001) group. LSM values were significantly higher in the obese group (5.5±2.3 kPa) than in the control (3.9±0.9, P<0.001), but there were no significant differences in LSM between the liver disease group (5.4±4.2) and either the obese or control group. LSM was highly correlated with CAP in the obese group (ρ = 0.511) but not in the control (ρ = 0.129) or liver disease (ρ = 0.170) groups.

Conclusions

Childhood obesity carries a high risk of hepatic steatosis associated with increased liver stiffness. FibroScan methodology provides simultaneous determination of CAP and LSM, is feasible in children of any age, and is a non-invasive and effective screening method for hepatic steatosis and liver fibrosis in Japanese obese children.

Ex Vivo characterization of canine liver tissue viscoelasticity after high-intensity focused ultrasound ablation

The potential of elasticity imaging to detect high-intensity focused ultrasound (HIFU) lesions on the basis of their distinct biomechanical properties is promising. However, information on the quantitative mechanical properties of the tissue and the optimal intensity at which to determine the best contrast parameters is scarce. In this study, fresh canine livers were ablated using combinations of ISPTA intensities of 5.55, 7.16 and 9.07 kW/cm(2) and durations of 10 and 30 s ex vivo, resulting in six groups of ablated tissues. Biopsy samples were then interrogated using dynamic shear mechanical testing within the range of 0.1-10 Hz to characterize the tissue's post-ablation viscoelastic properties. All mechanical parameters were found to be frequency dependent. Compared with unablated cases, all six groups of ablated tissues had statistically significant higher complex shear modulus and shear viscosity. However, among the ablated groups, both complex shear modulus and shear viscosity were found to monotonically increase in groups 1-4 (5.55 kW/cm(2) for 10 s, 7.16 kW/cm(2) for 10 s, 9.07 kW/cm(2) for 10 s, and 5.55 kW/cm(2) for 30 s, respectively), but to decrease in groups 5 and 6 (7.16 kW/cm(2) for 30 s, and 9.07 kW/cm(2) for 30 s, respectively). For groups 5 and 6, the temperature was expected to exceed the boiling point, and therefore, the decreased stiffening could be due to the compromised integrity of the tissue microstructure. Future studies will entail estimation tissue mechanical properties in vivo and perform real-time monitoring of tissue alterations during ablation.

The use of transient elastography and non-invasive serum markers of fibrosis in pediatric liver transplant recipients

The use of non-invasive markers to diagnose liver allograft fibrosis is not well established in children after LTx. TE, FT, and ELF score were performed in 117 liver-transplanted children (60M, 8.9 [0.5-18.5] yr) and 336 healthy controls. Liver biopsy was available in 36 children. Results of histology and non-invasive markers were compared using correlation coefficient or Mann-Whitney U-test as appropriate. TE correlated best with histological degree of fibrosis (r = 0.85 vs. r = 0.04 [FT] or r = -0.38 [ELF]). Liver stiffness values for transplanted children without fibrosis were significantly higher than those of healthy controls (7.55 [5.4-20.4] kPa vs. 4.5 [2.5-8.9] kPa). Presence of rejection was a potent confounder for the performance of TE. Both TE and FT reflected clinical changes (acute rejection, cholestasis, increasing fibrosis) in a total of 16 patients who underwent serial measurements. TE correlates better with histological degree of fibrosis in liver-transplanted children than FT or ELF, but an individual baseline value needs to be determined for each patient. Normal or cutoff values for pathological degrees of fibrosis cannot be transferred from non-transplanted children. Follow-up studies, preferably with protocol biopsies, might help to improve the diagnostic quality of TE.

The relationship between transient elastography and histological collagen proportionate area for assessing fibrosis in chronic viral hepatitis

BACKGROUND

Collagen proportionate area (CPA) has a better correlation with hepatic venous pressure gradient (HVPG) than with Ishak stage. Liver stiffness measurement (LSM) is proposed as non invasive marker of portal hypertension/disease progression. Our aim was to compare LSM and CPA with Ishak staging in chronic viral hepatitis, and HVPG in HCV hepatitis after transplantation.

METHODS

One hundred and sixty-nine consecutive patients with chronic hepatitis B virus (HBV) or hepatitis C virus (HCV) infections pre/post liver transplantation (LT), had a liver biopsy combined with LSM (transient elastography), CPA (biopsies stained with Sirius Red and evaluated by digital image analysis and expressed as CPA) and HVPG (measured contemporaneously with transjugular biopsies in LT HCV patients).

RESULTS

LSM was dependent on CPA in HBV (r (2) = 0.61, p < 0.0001), HCV (r (2) = 0.59, p < 0.0001) and LT groups (r (2) = 0.64, p < 0.0001). In all three groups, CPA and Ishak were predictors of LSM, but multivariately CPA was better related to LSM (HBV: r (2) = 0.61, p < 0.0001; HCV: r (2) = 0.59, p < 0.0001; post-LT: r (2) = 0.68, p < 0.0001) than Ishak stage. In the LT group, multiple regression analysis including HVPG, LSM, aspartate aminotransferase to platelet ratio index (APRI) and Ishak stage/grade, showed that only CPA was related to HVPG (r (2) = 0.41, p = 0.01), both for HVPG ≥6 mmHg (OR 1.34, 95 % CI 1.14-1.58; p < 0.0001) or ≥10 mmHg (OR 1.25, 95 % CI 1.06-1.47; p = 0.007).

CONCLUSION

CPA was related to LSM in HBV or HCV hepatitis pre/post-LT. CPA was better related to LSM than Ishak stage. In the LT HCV group, CPA was better related to HVPG than Ishak stage/grade, LSM or APRI. CPA may represent a better comparative histological index for LSM, rather than histological stages.

Ultrasound-based transient elastography for the detection of hepatic fibrosis in patients with recurrent hepatitis C virus after liver transplantation: a systematic review and meta-analysis

Ultrasound-based transient elastography (TE) is a promising noninvasive alternative to liver biopsy for the detection of hepatic fibrosis due to recurrent hepatitis C virus (HCV) after liver transplantation (LT). However, its overall test performance in various settings remains unknown. The aim of this study was to perform a systematic review and diagnostic accuracy meta-analysis of studies comparing ultrasound-based TE to liver biopsy for the detection of hepatic fibrosis due to a recurrent HCV infection after LT. Electronic and manual bibliographic searches (including scientific abstracts) were performed to identify potential studies. A meta-analysis was conducted to generate pooled estimates of the sensitivity values, specificity values, likelihood ratios, and diagnostic odds ratios of individual studies. The extent of the heterogeneity and the reasons for it were assessed. Six fully published studies were identified for analysis. Five studies that evaluated significant fibrosis were identified. Among these studies, the pooled estimates were 83% for sensitivity [95% confidence interval (CI) = 77%-88%], 83% for specificity (95% CI = 77%-88%), 4.95 for the positive likelihood ratio (95% CI = 3.4-7.2), 0.17 for the negative likelihood ratio (95% CI = 0.09-0.35), and 30.5 for the diagnostic odds ratio (95% CI = 12.8-72.4). For the 5 studies that assessed cirrhosis, the pooled estimates were 98% for sensitivity (95% CI = 90%-100%), 84% for specificity (95% CI = 80%-88%), 7 for the positive likelihood ratio (95% CI = 2.8-17.3), 0.06 for the negative likelihood ratio (95% CI = 0.02-0.19), and 130 for the diagnostic odds ratio (95% CI = 36.5-462.1). A diagnostic threshold (or cutoff value) bias was identified as an important cause of heterogeneity for the pooled results of both patient groups. In conclusion, ultrasound-based TE has excellent diagnostic accuracy for identifying cirrhosis due to a recurrent HCV infection after LT. The detection of significant fibrosis is more accurate for these patients versus patients whose native liver is chronically infected with HCV.

Use of transient elastography (FibroScan®) for the noninvasive assessment of portal hypertension in HIV/HCV-coinfected patients

The hepatic venous pressure gradient (HVPG) is the gold standard for assessing portal pressure and correlates with the occurrence of portal hypertension (PH)-related complications. Transient elastography (TE) is a new, highly accurate noninvasive technique, which enables us to evaluate hepatic fibrosis to detect advanced fibrosis and cirrhosis. We performed a hepatic haemodynamic study and TE in 38 HIV/HCV-coinfected patients. The association between HVPG and liver stiffness was assessed by linear regression. The diagnostic value of TE was assessed by receiver operating characteristic (ROC) curves. We considered clinically significant PH as an HVPG ≥ 10 mmHg and severe PH as an HVPG ≥ 12 mmHg. A total of 38 HIV/HCV-coinfected patients were included. Twenty-eight patients (73.7%) had clinically significant PH (HVPG ≥ 10 mmHg), and 23 (60.5%) of these had severe PH (HVPG ≥ 12 mmHg). We found a statistically significant association between liver stiffness (kPa) and HVPG (r(2) = 0.46, P < 0.001, straight line equation HVPG=7.4 + 0.204*TE). The areas under the ROC curves were 0.80 [95% confidence interval (CI), 0.64-0.97] and 0.80 (95% CI, 0.66-0.94) for the prediction of HVPG ≥ 10 and ≥ 12 mmHg, respectively. Our data suggest that TE can predict the presence of clinically significant and severe PH in HIV/HCV-coinfected patients.

Transient elastography for the diagnosis of liver fibrosis

Transient elastography (FibroScan(®)) is a noninvasive method proposed for the assessment of liver fibrosis in patients with chronic liver diseases by measuring liver stiffness. It can be easily performed at the bedside or in the outpatient clinic with immediate results and good reproducibility. FibroScan is validated for the diagnosis of significant fibrosis and cirrhosis in chronic hepatitis C, in recurrence of hepatitis C after liver transplantation, in co-infected HIV-HCV patients, in chronic hepatitis B, in chronic cholestatic diseases, in alcoholic disease and in nonalcoholic fatty liver disease. FibroScan is an excellent tool for the early detection of cirrhosis and for the evaluation of portal hypertension, and may have prognostic value in this setting. FibroScan evaluates liver stiffness, which is related to fibrosis, but also inflammation and portal hypertension. Therefore, FibroScan values have to be interpreted according to clinical, biological and morphological data.

Noninvasive tests for evaluation of fibrosis in HCV recurrence after liver transplantation: a systematic review

Noninvasive tests (NIT) for evaluation of hepatic fibrosis have not been evaluated extensively in liver transplantation. We systematically reviewed the literature regarding NIT after liver transplantation. We identified 14 studies evaluating NIT based on serum markers and/or liver imaging techniques: 10 studies assessed NIT in recipients with recurrent HCV infection for fibrosis and four studies evaluated predictors of progression of fibrosis in recurrent HCV. Transient Elastography (TE) had good discrimination for significant fibrosis (median AUROC: 0.88). Among the serum NIT, APRI had good performance (median AUROC: 0.75). TE performed better than serum (direct and indirect) NIT for significant fibrosis with median AUROC 0.88 (vs. 0.66, P < 0.001), median sensitivity 0.86 (vs. 0.56, P = 0.002), median NPV 0.90 (vs. 0.74, P = 0.05) and median PPV 0.80 (vs. 0.63, P = 0.02). TE compared to indirect serum NIT, had better performance, but was not superior to APRI score. Finally, direct, compared to indirect NIT, were not significantly different except for specificity: median: 0.83 vs. 0.69, respectively, P = 0.04. In conclusion, NIT could become an important tool in clinical management of liver transplant recipients, but whether they can improve clinical practice needs further evidence. Their optimal combination with liver biopsy and assessment of collagen content requires investigation.

Recent advances in the use of Fibroscan for diagnosis of liver fibrosis

In recent years, non-invasive methods for assessment of liver fibrosis have attracted worldwide attention. However, although many biochemical markers and imaging examinations have been used for evaluation of liver fibrosis, their sensitivity and specificity are low. Fibroscan (transient elastography) is a new non-invasive technology to assess the degree of liver fibrosis by measuring liver stiffness. Although Fibroscan has been extensively used to evaluate chronic hepatitis C and its complications in other countries, its use is uncommon in China. In this article, we will review its working principle, diagnostic value, and application status.