Non-invasive Investigations for the Diagnosis of Fontan-Associated Liver Disease in Pediatric and Adult Fontan Patients

Role of transient elastography in the diagnosis and prognosis of Fontan-associated liver disease

BACKGROUND

Fontan-associated liver disease (FALD) often occurs in patients with single-ventricle physiology following Fontan surgery, and ranges from liver congestion to cirrhosis. The assessment of the severity of FALD using noninvasive methods is challenging. However, transient elastography (TE) may be useful for the noninvasive evaluation of FALD and prediction of clinical outcomes.

AIM

To evaluate the role of TE in the diagnosis of FALD and its association with clinically relevant events.

METHODS

This retrospective single-center study (Hospital Universitario La Paz, Madrid), including 91 post-Fontan patients aged > 18 years old. Laboratory and ultrasound findings, and liver stiffness measurements (LSM) by TE (FibroScan®) were assessed. FALD was defined using ultrasound criteria (hepatomegaly, liver surface nodularity, parenchymal heterogeneity, hyperechoic lesions, splenomegaly, collaterals) and advanced FALD was defined according to the European Association for the Study of the Liver-European Reference Network statement (esophageal varices, portosystemic shunts, ascites, splenomegaly). Clinically relevant events included heart or heart-liver transplantation indication, hepatocellular carcinoma, and all-cause mortality.

RESULTS

Patient characteristics were: 60.4% male; Mean age, 33.3 ± 8.2 years; Mean elapsed time since surgery, 24.3 ± 7.7 years; 89% with FALD; 73% with advanced FALD. LSM by TE was associated with FALD [odds ratio (OR) = 1.34; 95% confidence interval (95%CI): 1.10-1.64; P = 0.003] and advanced FALD (OR = 1.10; 95%CI: 1.01-1.19; P = 0.023). Areas under the curve (AUC) were 0.905 and 0.764 for FALD and advanced FALD, respectively. FALD cut-off values comprised: Optimal, 20 kPa (sensitivity: 92.3%; specificity: 80.0%); Rule-out, 15 kPa (sensitivity: 96.9%); Rule-in, 25 kPa (specificity: 100%). A FALD algorithm was proposed based on LSM by TE and elapsed time since surgery (AUC: 0.877; sensitivity, 95.4%; specificity, 80.0%; positive predictive value, 96.9%; negative predictive value, 72.7%). LSM by TE was associated with clinically relevant events (OR = 1.07; 95%CI: 1.01-1.13; P = 0.021) and all-cause mortality (OR = 1.23; 95%CI: 1.02-1.47; P = 0.026).

CONCLUSION

In adult patients post-Fontan surgery, TE is a useful noninvasive method for FALD diagnosis. The association between LSM by TE and clinically relevant events suggests a role in prognosis.

Clinical predictors and noninvasive imaging in Fontan-associated liver disease: A systematic review and meta-analysis

BACKGROUND

Despite the development of several imaging modalities for diagnosing Fontan-associated liver disease (FALD), there is no optimal protocol for the follow-up of FALD. We conducted a systematic review and meta-analysis to identify factors related to liver fibrosis using biopsy reports and to identify alternative noninvasive modalities that could better reflect liver histological changes in FALD.

METHODS

A systematic review and meta-analysis were conducted following the PRISMA guidelines Table S2. We searched Embase, PubMed, and Cochrane databases for studies on FALD, focusing on those assessing clinical factors associated with liver fibrosis severity through liver biopsy and noninvasive imaging techniques.

RESULTS

A total of 42 studies were identified, of which 12 conducted meta-analyses and subgroup analyses of the severity of liver fibrosis using liver biopsies. Liver biopsy results showed a weak positive correlation between Fontan duration and fibrosis severity (R = 0.36). Subgroup analyses revealed significant differences in hemodynamic parameters, such as Fontan pressure, between patients with mild and severe fibrosis. Platelet count, aspartate aminotransferase to platelet ratio index, and fibrosis-4 index were significantly associated with fibrosis severity, with severe fibrosis showing lower platelet counts and higher aspartate aminotransferase to platelet ratio index and fibrosis-4 index levels. Noninvasive imaging modalities, particularly magnetic resonance elastography and shear wave elastography, demonstrated strong correlations with biopsy-confirmed fibrosis severity.

CONCLUSIONS

This study identifies key clinical factors, and noninvasive modalities accurately reflect liver fibrosis severity in patients with FALD. Clinical factors such as platelet count, aspartate aminotransferase to platelet ratio index, and fibrosis-4 index may aid in identifying patients at risk for severe fibrosis. In addition, magnetic resonance elastography and shear wave elastography are promising tools for noninvasive assessment in our study. Further research is needed to refine these diagnostic approaches and improve patient management.

Fontan-associated liver disease: the importance of multidisciplinary teamwork in its management

The Fontan operation, which directly connects the superior and inferior vena cava to the pulmonary artery, is a palliative surgery for children with a functional or anatomic single ventricle. This procedure leads to hemodynamic changes (Fontan circulation) in patients, who tend to develop congestive hepatic fibrosis characterized by sinusoidal fibrosis and dilatation beginning approximately 10 years after the procedure. In addition, in the context of severe fibrosis and cirrhosis, hepato-gastrointestinal complications including hepatocellular carcinoma, focal nodular hyperplasia, and portal hypertension can arise. Fontan-associated liver disease (FALD) encompasses the broad spectrum of liver alterations secondary to postoperative hemodynamic changes, and the effective management of FALD requires contributions from specialists in hepatology, gastroenterology, surgery, radiology, histopathology, and pediatric and adult cardiology. In this article, we outline the pathogenesis of FALD and discuss the importance of a multidisciplinary collaborative approach to its management.

Shear-wave elastography for monitoring Fontan-associated liver disease: A prospective cohort study

The spectrum of Fontan-associated liver disease (FALD) varies from abnormal liver function tests to fibrosis and even cirrhosis. In this prospective study, we evaluated the role of shear-wave elastography (SWE) in predicting the presence of advanced FALD. Forty-eight patients (30 males, 13.9 [6-21] years) with a Fontan circulation were evaluated at 8.3 (2.1-18.7) years since the Fontan surgery. The median liver stiffness measurement (LSM) value was higher than values in normal children at 15.4 (9.5-38.7) kPa. The LSMs had a weak but significant correlation with age at the time of LSM (r = 0.25, p = 0.01) and duration post-Fontan surgery (r = 0.31, p = 0.02). It had a poor correlation with the concomitant aspartate transaminase-to-platelet ratio index (r = 0.1, p = 0.39). No difference in the elastography values between children with and without ultrasound evidence of advanced liver disease (17.7 [interquartile range, IQR: 4] vs. 16.1 [IQR: 6], p = 0.62] was observed. Further studies are required to determine the precise role of SWE as a noninvasive marker of liver fibrosis in FALD.

FibroScan as a surveillance marker post-cavopulmonary anastomosis for single-ventricle physiology

Purpose

Single-ventricle physiology encompasses a group of congenital cardiac malformations with only one functional ventricle. The Fontan procedure is the final palliation of this pathway and has its complications. One of these is Fontan-associated liver disease (FALD). It is known that all patients with Fontan will have FALD, due to the physiology of the Fontan circuit, and only the severity will vary. The pathophysiology of hepatic damage in FALD is unique and not easily detectable by routine non-invasive investigations. Therefore, this study is aimed to identify if FibroScan can be used as a surveillance marker to detect and assess the progression of FALD.

Methods

Patients who attended the Cardiothoracic and Vascular Surgery Outpatient Department (OPD) for follow-up post-cavopulmonary anastomosis (bidirectional Glenn and Fontan) were enrolled in this study. They underwent routine examinations and tests, and in addition a FibroScan was performed.

Results

FibroScan showed that the liver stiffness measurement (LSM) was increased in all patients who had undergone Fontan and a couple of patients who had undergone bidirectional (BD) Glenn. The LSM was 12.29 (± 3.59) kPa in patients post-Fontan and 6.64 (± 4.24) kPa in patients post-BD Glenn. This raised LSM was not associated with a parallel rise in liver enzymes or other laboratory markers associated with liver function. This emphasizes the suitability of FibroScan as an early and non-invasive surveillance tool for monitoring the progression of hepatic venous congestion and FALD.

Conclusion

We have found that LSM via FibroScan can effectively be a surveillance or screening test for FALD. Serial FibroScans can be used to monitor the progress of liver disease. Raised LSM may also have a role in predicting the morbidity for completion of Fontan post-BD Glenn operation. Large-scale studies are needed to validate our findings.

Lymphopenia in the Adult Population With Fontan Physiology: A Potential New Marker for Disease Assessment

Background

Patients with complex congenital heart disease and Fontan palliation frequently develop extracardiac disease, including hematologic abnormalities, such as lymphopenia. However, the clinical implications of this finding are poorly understood and are therefore the topic of this investigation.

Methods

Patients with Fontan physiology in our centre (1999-2018) were evaluated for the presence and impact of lymphopenia. The cohort was divided into a group with lymphopenia (L) (2 consecutive absolute lymphocyte counts ≤ 1∗103 K/ μL) and a group who had never had lymphopenia (NL). Clinical characteristics and hospital admissions (762 patient-years) were evaluated.

Results

In 62 adult patients with Fontan physiology (aged 34 ± 9 years; 32 women [52%]), the patients who developed lymphopenia earliest did so 8 years after Fontan completion, with up to 60% of patients developing lymphopenia by 30 years. Lymphopenia was found to be associated with portal hypertension (varices, ascites, splenomegaly, and thrombocytopenia [VAST] score)-NL: 0 (0-2) vs L: 2 (0-4), P < 0.0001). A total of 76 heart failure and 81 arrhythmia-associated admissions occurred per 1000 patient-years. At 40 years post-Fontan, the probability of a heart failure admission was higher in the L group (L: 51 [86%] vs NL: 8 [14%], P < 0.01).

Conclusions

Adult patients with Fontan physiology and lymphopenia demonstrated portal hypertension and lymphatic dysfunction more commonly, perhaps suggesting that this may be a marker of Fontan congestion and early Fontan failure. Further investigation into the relationship between lymphopenia, clinical outcomes, and Fontan function is needed.

Meta-analysis: Incidence of cirrhosis and hepatocellular carcinoma in patients with Fontan palliation

BACKGROUND AND AIMS

The Fontan palliation is the final stage of surgery for many children born with univentricular physiology. Almost all Fontan patients develop liver fibrosis which may eventually lead to cirrhosis and hepatocellular carcinoma (HCC). These are important causes of morbidity and mortality in these patients. We performed a systematic review and meta-analysis to assess the incidence of cirrhosis and HCC in Fontan patients and stratify it based on time since surgery.

METHODS

A literature search of seven databases identified 1158 records. Studies reporting the number of cirrhosis and HCC cases in Fontan patients and time since Fontan surgery were included. In the cirrhosis cohort, we included only those studies where all patients underwent liver biopsy.

RESULTS

A total of 23 studies were included: 12 and 13 studies in the cirrhosis and HCC cohorts, respectively, with two studies included in both cohorts. The incidence of cirrhosis was 0.97 per 100 patient-years (95% CI 0.57-1.63), with the incidence and cumulative incidence ≥20 years post Fontan surgery being 1.61 per 100 patient-years (95% CI 1.24-2.08) and 32.2% (95% CI 25.8%-39.4%), respectively. The incidence of HCC was 0.12 per 100 patient-years (95% CI 0.07-0.21), with the incidence and cumulative incidence ≥20 years post Fontan surgery being 0.20 per 100 patient-years (95% CI 0.12-0.35) and 3.9% (95% CI 2.2%-6.8%), respectively. Only about 70% of patients with HCC (20/28) had underlying cirrhosis.

CONCLUSION

The incidence of cirrhosis and HCC increases over time, especially at ≥20 years post Fontan surgery. Studies are needed to further identify at-risk patients in order to streamline surveillance for these highly morbid conditions.

Mitochondrial dysfunction is associated with the severity of liver fibrosis in patients after the Fontan operation

The gold standard for determining the severity of liver disease in Fontan patients is now liver biopsy. Since it is an invasive procedure, this study determined the possibility of applying mitochondrial function from isolated peripheral blood mononuclear cells (PBMCs) as a non-invasive indicator of liver fibrosis. Fontan patients (n = 37) without known liver disease were analysed cross-sectionally. Patients were classified according to their histology using the METAVIR score as follows; F0/F1-no/mild fibrosis; F2-moderate fibrosis; and F3/F4-cirrhosis. Peripheral blood mononuclear cells were assessed for mitochondrial activity and apoptosis. This study did not find any significant differences in cardiac function among the groups according to liver histology. Interestingly, our findings indicated a significant decrease in maximal respiration and spare respiratory capacity, in both the moderate (F2) and cirrhosis (F3/F4) groups compared with the group without significant fibrosis (F0/F1). Moreover, the cirrhosis group exhibited higher levels of apoptosis and lower levels of live cells, compared with both the moderate and no significant fibrosis groups. In conclusion, the degree of liver fibrosis in Fontan patients is strongly correlated with mitochondrial dysfunction in PBMCs. Mitochondrial function and apoptosis could potentially serve as novel markers for tracking the progression of liver fibrosis in these patients.

Poor correlation of 2D shear wave elastography and transient elastography in Fontan-associated liver disease: A head-to-head comparison

Background and Aims

Fontan-associated liver disease (FALD) is a long-term complication of the Fontan procedure. Guidelines recommend elastography, but the utility of transient elastography (TE) and two-dimensional shear wave elastography (2D SWE) is unknown. We aimed to evaluate the relationship between TE and 2D SWE in FALD.

Methods

This prospective cohort study included 25 patients managed in a specialist clinic between January 2018 and August 2021. Trained clinicians performed 2D SWE (GE Logiq-E9) and TE (FibroScan 503 Touch) on the same day under the same conditions. Laboratory, echocardiography, and imaging data were collected. The atrioventricular systolic-to-diastolic duration (AVV S/D ratio) was calculated as a measure of cardiac diastolic function.

Results

We analyzed 40 paired measurements. Median age was 22 years. Median liver stiffness measurement (LSM) was 15.4 kPa (12.1-19.6) by TE and 8.0 kPa (7.0-10.3) (P = 0.001) by 2D SWE. There was weak correlation between the modalities (r = 0.41, P = 0.004). There was no correlation between time since Fontan and LSM by TE (r = 0.15, P = 0.19) or 2D SWE (r = 0.19, P = 0.13). There was no difference in LSM irrespective of whether sonographic cirrhosis was present or absent by TE (17.4 kPa [15.9-23.6] vs. 14.9 kPa [12.0-19.4], respectively, P = 0.6) or 2D SWE (9.0 kPa [2.8-10.5] vs. 8.0 kPa [6.7-10.1], P = 0.46). There was no correlation between AVV S/D ratio and LSM by TE (r = 0.16, P = 0.18) or 2D SWE (r = 0.02, P = 0.45).

Conclusions

In FALD, TE and 2D SWE are poorly correlated. LSM by either modality was not associated with known risk factors for liver fibrosis or Fontan function. Based on these data, the role of elastography in FALD is uncertain.

Reliability of transient elastography as a noninvasive method for estimating central venous pressure in adult patients after a Fontan procedure

Background

In adult patients, after a Fontan procedure, high central venous pressure (CVP) is a hemodynamic risk factor associated with poor prognosis. High liver stiffness (LS) on transient elastography (TE) is associated with high CVP in patients with heart failure without liver disease. Here, we investigated whether LS assessment using TE is a reliable method to noninvasively evaluate CVP in adult patients after a Fontan procedure, who can present varying degrees of liver fibrosis as a complication.

Methods

We measured LS using TE and CVP by cardiac catheterization in 24 adult patients who had undergone a Fontan procedure. The estimated CVP was calculated using the previously reported formula: -5.8 + 6.7 × ln[LS]. We examined the correlation between LS and CVP, and degree of agreement between the estimated and measured CVPs. Patients were divided into two groups, with or without suspected liver cirrhosis, based on abdominal imaging studies.

Results

The median patient age was 35 years (interquartile range 25, 39). Overall, there was a strong correlation between LS and CVP (ρ = 0.83, p < 0.001). The estimated CVP based on LS and the CVP measured using cardiac catheterization were positively correlated; however, the estimated CVP tended to be higher than the measured CVP (mean difference 0.9 mmHg [95% limits of agreement: -2.8 to 4.6 mmHg]). These results were consistent across all groups.

Conclusions

In adult patients after a Fontan procedure, LS measured by TE showed a positive correlation with CVP by cardiac catheterization. TE can be useful as a noninvasive estimation of CVP.

Fontan Hepatopathy - Managing Unknowns

BACKGROUND AND AIMS

How to best monitor Fontan associated liver disease (FALD) remains unclear. We describe results from a prospective liver care pathway in adults (n=84) with a Fontan circulation.

METHODS

Routine assessment of the liver, by acoustic radiation force frequency and ultrasound was undertaken. Results, including liver biochemistry, systemic ventricular function (echocardiography), functional class, medication use and clinical endpoints (varices, hepatocellular carcinoma, heart transplantation and death) were collated.

RESULTS

Most individuals returned a cirrhotic range acoustic radiation force impulse imaging (ARFI) result. ARFI values were greater in the proportion of individuals with hepatic nodularity (p=0.024). Univariate analysis demonstrated moderate correlation with platelet number (Spearmans rho= -0.376, p=0.049). Patients with clinical endpoints had lower platelets (p=0.012) but only a trend to hepatic nodularity (p=0.057). Clinical endpoints were more common in those with ventricular dysfunction (p=0.011). Multivariate analysis revealed that age at Fontan and being on angiotensin converting enzyme inhibitors (ACEI) predicted ARFI score (β=0.06 (95% CI 0.01-0.09), p=0.007 and β=0.53 (95% CI 0.17-0.89), p=0.005, respectively). However, these associations were not significant once adjusted for Fontan type, age at ARFI, systemic ventricle morphology, ventricle function, or Model for End-stage Liver Disease (MELD-XI) excluding international normalised ratio (INR) (p>0.05 for all).

CONCLUSIONS

Ideal FALD monitoring remains unclear. ARFI has utility as a binary non-invasive indicator of cirrhosis, highlighting individuals who may need more frequent ongoing monitoring for hepatocellular carcinoma. However, no definite advantage to serial ARFI, once cirrhotic range ARFI results are present, has been identified.

Combined hepatocellular carcinoma-cholangiocarcinoma in a patient with Fontan-associated liver disease

We present a rare case of combined hepatocellular carcinoma-cholangiocarcinoma in a woman with a history of univentricular congenital heart disease requiring multiple corrective operations including Fontan procedure. During workup for elevated alpha fetal protein, a right hepatic lobe lesion was identified with biopsy showing poorly differentiated hepatocellular carcinoma. She underwent successful segment 5 liver resection. Final pathology demonstrated combined hepatocellular carcinoma-cholangiocarcinoma. She was treated with gemcitabine/oxaliplatin adjuvant chemotherapy and had no evidence of recurrent disease at her 12-month follow-up. To our knowledge, this is the first case reported in of successful treatment of this rare malignancy in the setting of Fontan-associated liver disease and highlights the importance of a robust screening protocol in this patient population. Semiannual screening for the development of primary liver malignancy should start by 10 years post-Fontan and continue until heart-liver transplantation may be performed. It is important to note that cirrhosis is not a pre-requisite for the development of hepatocellular carcinoma or cholangiocarcinoma in these patients.

Care Pattern for Fontan-Associated Liver Disease by Academic Pediatric Hepatologists in Canada

Fontan-Associated Liver Disease (FALD) is a common extracardiac complication seen in patients following the Fontan procedure. There are no consensus guidelines on screening and management of children with FALD.

Objective

The current study aims to determine academic pediatric hepatologists' practices and identify variability in management provided to children with FALD in Canada.

Methods

Using the infrastructure of the Canadian Pediatric Hepatology Research Group, a nationwide survey was distributed electronically to all pediatric hepatologists practicing in university-affiliated hospitals.

Results

Twelve pediatric hepatologists from 12 of 13 academic centers (92%) responded to the survey. The institutions of only 2 (17%) physicians offer post-Fontan care with a multidisciplinary team, both from different provinces. The screening for other comorbidities, use of noninvasive modality, and timing of liver biopsy for estimation of liver fibrosis and screening for esophageal varices differ from program to program. The frequency of outpatient clinic follow-up varies significantly. Education and counseling concerning liver health are generally used as treatment; only 58% of academic centers have a formal adult care transition plan.

Conclusions

Significant discrepancies exist in the care provided to children with FALD by hepatologists practicing in academic centers across Canada. Future study is needed to develop a standardized protocol for managing and following children and youth with FALD.

Liver Disease Assessment in Children with Fontan and Glenn Surgeries for Univentricular Hearts—The Role of Elastography and Biochemical Fibrosis Markers

Background: Children born with single-ventricle hearts require surgery in order to survive. Liver fibrosis is a known complication of Fontan surgery for univentricular hearts. Methods: In this study on 13 post-Fontan and 21 post-Glenn patients, we used elastography (shearwave and transient elastography) as well as serum biochemical fibrosis markers to evaluate the degree of liver fibrosis in comparison to 32 controls. Results: The mean Emedian and Vmedian values determined by shear wave elastography in the Fontan Group were significantly higher than the controls (4.85 kPa vs. 3.91 kPa and 1.25 m/s vs. 1.12 m/s, respectively). Fontan patients had significantly increased Fibrotest, Actitest, AST-to-Platelet Ratio index, ALT and GammaGT levels compared to controls. For post-Glenn patients, the mean Emedian and Vmedian values were similar to healthy controls, whereas the Fibrotest, Actitest and AST-to-Platelet Ratio index were significantly increased. Using transient elastography, we found significantly higher values for Emedian and Vmedian in Fontan patients compared to Glenn patients. Conclusions: Elastography and biochemical fibrosis markers are valuable non-invasive tools for screening and monitoring liver fibrosis in patients with Fontan and Glenn interventions.

Liver nodules after the Fontan operation: role of the computerised tomography scan

Currently, there is an increasing prevalence of liver nodules in patients following the Fontan operation. The appropriate non-invasive modalities have been applied to assess a diagnosis of Fontan-associated liver disease. The aims of this study were to determine the prevalence and associated factors for the presence of liver nodules using CT scan. A cross-sectional study of 34 patients older than 15 years of age was recruited. Ultrasound upper abdomen, ultrasound liver elastography, and CT scan of the upper abdomen were performed after the Fontan operation. The median age of patients was 20 years (range 14-36 years). The median age at the Fontan operation was 7 years (range 5-17 years) and the duration after the Fontan operation was 12 years (range 4-22 years). The prevalence of liver nodules was 62% as detected by CT scans. Hepatic vein pressure in patients with liver nodules was significantly higher than in those without liver nodules. Hepatic vein pressure above 13 mmHg was a factor associated with liver nodules. There was little agreement between the ultrasound of the upper abdomen and CT scan of the upper abdomen in the evaluation of liver nodules. Hepatic pressure was the only associated factor for the occurrence of liver nodules in patients following the Fontan operation. The prevalence of liver nodules was very high after the Fontan operation. The upper abdomen CT scan should be performed for the surveillance of liver nodules in every Fontan patient over the age of 15 years.

Screening modalities for the diagnosis of Fontan-associated liver disease: evidence from the past for future development

Approximately 70,000 patients who have undergone the Fontan operation worldwide survive into adulthood, however the majority of these patients are faced with long-term post-operative complications due to specific hemodynamic changes. Fontan-associated liver disease (FALD) is a challenging complication characterized by various spectra. Of these, liver congestion and liver fibrosis potentially lead to cirrhosis and liver nodules. The most serious condition associated with the development of liver nodules is hepatocellular carcinoma. Various non-invasive modalities including blood tests, ultrasound scans of the upper abdomen, ultrasound elastography of the liver, computed tomography scans, magnetic resonance imaging and magnetic resonance elastography of the liver have been used as alternatives to liver biopsies for FALD assessment in post-Fontan patients. To date, a detailed understanding of the pathophysiology and natural history of these patients, and the most appropriate modality for the effective investigation of this condition is incomplete. In this comprehensive review, reports regarding the currently available screening modalities used in the detection of FALD are summarized and discussed. The findings of this review, including identification of any current knowledge gaps, can pave the way for the development of effective future strategies in the surveillance and ultimately the treatment of post-Fontan patients.

Current Treatment Options for the Failing Fontan Circulation

The Fontan operation was introduced in 1968. For congenital malformations, where biventricular repair is unsuitable, the Fontan procedure has provided a long-term palliation strategy with improved outcomes compared to the initially developed procedures. Despite these improvements, several complications merely due to a failing Fontan circulation, including myocardial dysfunction, arrhythmias, increased pulmonary vascular resistance, protein-losing enteropathy, hepatic dysfunction, plastic bronchitis, and thrombo-embolism, may occur, thereby limiting the life-expectancy in this patient cohort. This review provides an overview of the most common complications of Fontan circulation and the currently available treatment options.

Role of Transient Elastography to Stage Fontan-Associated Liver Disease (FALD) in Adults with Single Ventricle Congenital Heart Disease Correction

Fontan-associated liver disease (FALD) is an arising clinical entity that can occur long after a successful Fontan operation for correction of single ventricle (SV) congenital heart disease (CHD). Occurrence of FALD is characterized by liver cirrhosis and other hepatic complications, and determinates an increased morbidity and mortality. Currently, there is no consensus on how to stage FALD. We report here our experience by an observational study in 52 patients with SV-CHD after Fontan operation that were recruited through a period of 36 ± 9.3 months. All cases underwent lab tests and liver and cardiac imaging evaluation, including liver stiffness (LS) measurement by transient elastography (TE) (FibroScan®). According to selective criteria for liver disease, we identified 23/43 (53.5%) cases with advanced FALD that showed: older age (p < 0.05), larger hepatic and cava veins diameter (p < 0.05), worsened NYHA class (p < 0.05), abnormal lymphocytes (p < 0.01), platelet count (p < 0.05), and GGT, prothrombin time (INR), albumin and cystatin C levels (p < 0.05), with respect to cases without advanced FALD. LS values were significantly increased in cases with advanced FALD, at cut-off values higher than 22 kPa (p < 0.001). LS, and its combined score with spleen diameter and platelet count (LSPS) successfully helped to detect 100% of cases with portal hypertension (p < 0.001). In conclusion, LS can be effective to stage FALD and to uncover cases with severe risk of complications, avoiding higher morbidity and mortality related to advanced FALD.

Elastography for Pediatric Chronic Liver Disease: A Review and Expert Opinion

In adults with chronic liver diseases, ultrasound and magnetic resonance shear wave elastography (SWE) can replace liver biopsy in several clinical scenarios. Several guidelines on the use of ultrasound SWE for the adult population have been published. However, the number of publications in the pediatric population is limited, and available guidelines on SWE do not specifically address pediatric chronic liver diseases. In this article, we review the literature on the use of SWE for pediatric chronic liver diseases and provide expert opinion on how to use SWE, both ultrasound and magnetic resonance techniques, in the pediatric population.

Associated Factors of Liver Disease After Fontan Operation in Relation to Ultrasound Liver Elastography

Although the Fontan operation can improve outcomes, surviving patients still face Fontan-associated liver disease (FALD). The aim of this study was to determine the associated factors of FALD in relation to ultrasound liver elastography. A cross-sectional study was conducted for all patients on whom an ultrasound upper-abdomen and ultrasound liver elastography was performed at more than 1 year after the Fontan operation. The data consisted of the age at operation, type of Fontan operation, and laboratory data such as gamma-glutamyl transferase (GGT), aspartate aminotransferase-to-platelet ratio index (APRI), and fibrosis-4 (FIB-4) score. Cardiovascular evaluations included echocardiography and cardiac catheterization. Eighty patients with a median age of 12 years (range 5-36 years) were eligible for the study. The prevalence of FALD was 41%. For the purpose of univariate logistic regression analysis, the age at the Fontan operation, time elapsed since the Fontan operation, previous Glenn shunt, presence of fenestration, mean pulmonary artery pressure and IVC pressure post-Fontan operation, platelet count, GGT, and FIB-4 score were considered to be factors significantly associated with FALD. Following an adjustment by multivariate logistic regression analysis, age greater than 7 years at the time of Fontan procedure, time elapsed of more than 9 years since the procedure, and GGT level > 130 U/L were found to be significantly associated with FALD. Patients with these factors should be investigated for FALD.

Fontan-associated liver disease: pathophysiology, investigations, predictors of severity and management

Cardiac hepatopathy is the liver injury resulting from congestion and ischaemia associated with acute or chronic heart failure. The improved longevity of adults with operated congenital heart disease who develop heart failure as an increasingly late event makes this form of liver injury increasingly clinically relevant. Patients with congenital heart disease with a single ventricle anomaly, who require creation of a Fontan circulation, are particularly vulnerable as they have elevated venous filling pressures with chronic liver congestion. Progression to liver fibrosis and eventually cirrhosis may occur, with its associated risks of liver failure and hepatocellular carcinoma. This risk likely increases over the patient's lifetime, related to the duration post-surgical repair and reflects the chronicity of congestion. Liver biopsy is rarely performed due to a higher risk of complications in the setting of elevated venous pressures, and the frequent use of anticoagulation. Non-invasive methods of liver assessment are poorly validated and different factors require consideration compared to other chronic liver diseases. This review discusses the current understanding of cardiac hepatopathy in congenital heart disease patients with a Fontan circulation. This entity has recently been called Fontan Associated Liver Disease in the literature, with the term useful in recognising that the pathophysiology is incompletely understood, and that long-standing venous pressure elevation and hypoxaemia are presumed to play an additional significant role in the pathogenesis of the liver injury.

Severity of Fontan-Associated Liver Disease Correlates with Fontan Hemodynamics

Fontan-palliated patients are at risk for the development of Fontan-associated liver disease (FALD). In this study, we performed a detailed hemodynamic and hepatic assessment to analyze the incidence and spectrum of FALD and its association with patients' hemodynamics. From 2017 to 2019, 145 patients underwent a detailed, age-adjusted hepatic examination including laboratory analysis (FibroTest^®, n = 101), liver ultrasound (n = 117) and transient elastography (FibroScan^®, n = 61). The median patient age was 16.0 years [IQR 14.2], and the median duration of the Fontan circulation was 10.3 years [IQR 14.7]. Hemodynamic assessment was performed using echocardiography, cardiopulmonary exercise capacity testing and cardiac catheterization. Liver ultrasound revealed hepatic parenchymal changes in 83 patients (70.9%). Severe liver cirrhosis was detectable in 20 patients (17.1%). Median liver stiffness measured by FibroScan^® was 27.7 kPa [IQR 14.5], and the median Fibrotest^® score was 0.5 [IQR 0.3], corresponding to fibrosis stage ≥ 2. Liver stiffness values and Fibrotest^® scores correlated significantly with Fontan duration (P₁ = 0.013, P₂ = 0.012). Exercise performance was significantly impaired in patients with severe liver cirrhosis (P = 0.003). Pulmonary artery pressure and end-diastolic pressure were highly elevated in cirrhotic patients (P₁ = 0.008, P₂ = 0.003). Multivariable risk factor analysis revealed Fontan duration to be a major risk factor for the development of FALD (P < 0.001, OR 0.77, CI 0.68-0.87). In the majority of patients, hepatic abnormalities suggestive of FALD were detectable by liver ultrasound, transient elastography and laboratory analysis. The severity of FALD correlated significantly with Fontan duration and impaired Fontan hemodynamics. A detailed hepatic assessment is indispensable for long-term surveillance of Fontan patients.

Liver disease secondary to congenital heart disease in children

Introduction: Hepatic fibrosis and hepatocellular carcinoma (HCC) can develop in children with congenital heart disease. Although hepatic fibrosis and HCC are prone to develop after the Fontan operation, they can also develop in patients suffering from congenital heart disease who have not undergone Fontan operation. Area covered: The history of cardiac hepatopathy including Fontan-associated liver disease is described. Patient characteristics, liver histology, imaging examinations and blood tests are reviewed to elucidate the mechanism of cardiac hepatopathy. In addition, a flowchart for the follow-up management of cardiac hepatopathy in children with congenital heart disease is proposed. Expert opinion: Congestion and low cardiac output are the main causes of cardiac hepatopathy. Advanced hepatic fibrosis is presumed to be associated with HCC. HCC can develop in both adolescents and young adults. Regardless of whether the Fontan operation is performed, children with a functional single ventricle and chronic heart failure should be regularly examined for cardiac hepatopathy. There is no single reliable laboratory parameter to accurately detect cardiac hepatopathy; hepatic fibrosis indices and elastography have shown inconsistent results for detection of this disease. Further studies using liver specimen-confirmed patients and standardization of evaluation protocols are required to clarify the pathogenesis of cardiac hepatopathy.

Assessment of liver T1 mapping in fontan patients and its correlation with magnetic resonance elastography-derived liver stiffness

OBJECTIVES

To explore the utility of liver T1 mapping in Fontan patients and its correlation to magnetic resonance elastography (MRE)-derived liver stiffness.

BACKGROUND AND AIMS

Liver disease is a major long-term extra cardiac complication in the Fontan population. MRE is frequently used to quantify liver stiffness in Fontan patients; however, it has certain limitations. Native T1 mapping by cardiac magnetic resonance (CMR) is useful in assessment of cardiac fibrosis, but its potential in evaluating liver fibrosis and its correlation to MRE-derived liver stiffness in Fontan patients have not been reported.

METHODS

Fontan patients who underwent CMR and MRE were included. Liver Native T1, extracellular volume (ECV) and delta coefficients were measured and correlated with MRE-derived liver stiffness in all Fontan patients. Native liver T1 in Fontan patients were compared to normal controls with biventricular circulation and no known liver disease.

RESULTS

A total of 17 Fontan patients and 7 normal controls were included in this study. Fontan patients had significantly higher liver native T1 (690 ± 41 ms vs 620 ± 35 ms; p < 0.001) as compared to controls. There was strong positive correlation between MRE derived liver stiffness and liver native T1 (r = 0.81, p < 0.001).

CONCLUSIONS

Liver native T1 was significantly elevated in Fontan patients compared to controls and strongly correlated with MRE-derived liver stiffness. This technique may prove to be a useful noninvasive imaging biomarker for assessing liver fibrosis in the Fontan population.

Frontiers in Fontan failure: Innovation and improving outcomes: A conference summary

The initial "Frontiers in Fontan Failure" conference in 2015 in Atlanta, GA, provided an opportunity for experts in the field of pediatric cardiology and adult congenital heart disease to focus on the etiology, physiology, and potential interventions for patients with "Failing Fontan" physiology. Four types of "Fontan Failure" were described and then published by Dr Book et al. The acknowledgment that even Dr Fontan himself realized that the Fontan procedure "imposed a gradually declining functional capacity and premature late death after an initial period of often excellent palliation." The purpose of the second "Frontiers in Fontan Failure" was to further the discussion regarding new data and technologies as well as novel interventions. The 2017 "Frontiers in Fontan Failure: Innovation and Improving Outcomes" was sponsored by Children's Healthcare of Atlanta, Sibley Heart Center Cardiology, and Emory University School of Medicine. Future directions in the management of Fontan failure include further investigations into the risk of sudden cardiac death and how to properly prevent it, achievable interventions in modifying the Fontan physiology to treat or prevent late complications, and improved and refined algorithms in Fontan surveillance. Finally, further research into the interventional treatment of lymphatic-related complications hold the promise of marked improvement in the quality of life of advanced Fontan failure patients and as such should be encouraged and contributed to.

FibroSURE and elastography poorly predict the severity of liver fibrosis in Fontan-associated liver disease

OBJECTIVE

As the population of patients with Fontan circulation surviving into adulthood increases, hepatic cirrhosis has grown to be a significant cause of morbidity and mortality. Early detection of advanced hepatic fibrosis is imperative for proper intervention and consideration for heart or combined heart/liver transplantation. Noninvasive biomarkers and elastography have been evaluated for their diagnostic utility with variable results in the Fontan population.

DESIGN

The cohort included 14 patients age 26.4 SD 7.5 who underwent Fontan surgery. All patients were evaluated with FibroSURE, shear wave elastography (SWE), hepatic duplex sonography, and liver biopsy. Liver fibrosis on biopsy was evaluated according to the congestive hepatic fibrosis system.

RESULTS

In our cohort, 100% of patients had fibrosis with 36% demonstrating advanced fibrosis. FibroSURE agreed with liver biopsy in only 5 out of 14 cases (36%): underestimating in 7 and overestimating in 2 individuals. SWE agreed with liver biopsy in 0% of cases: overestimating in 10 and underestimating in 4 cases. None of the duplex sonography indices predicted the presence or severity of liver fibrosis.

CONCLUSION

This study demonstrates that children who have undergone a Fontan procedure universally develop some hepatic fibrosis and a significant number have advanced fibrosis by adulthood. The FibroSURE blood test, SWE, and hepatic duplex sonography were unable to accurately predict the presence or severity of hepatic fibrosis when compared with liver biopsy. Further studies are needed to investigate novel noninvasive methods and/or biomarkers that can adequately detect advanced hepatic fibrosis before the development of cirrhosis and hepatic decompensation.

Liver abnormalities and post-transplant survival in pediatric Fontan patients

The impact of liver parenchymal abnormalities on survival post-heart transplant remains unknown in pediatric Fontan patients. We assessed pediatric Fontan patients who underwent heart transplant and had documented pretransplant hepatic ultrasound (U/S) studies. Liver U/S findings were classified as normal (Group 1), mildly abnormal (Group 2, hepatomegaly/vascular congestion), or severely abnormal (Group 3, heterogeneous echotexture/nodularity). Among 30 study patients, 8 were classified as Group 1, 14 as Group 2, while 8 met Group 3 criteria. Pretransplant liver biochemistry and synthetic function were similar in all groups. Six Group 3 patients underwent liver biopsy; 4 demonstrated perisinusoidal or centrilobular fibrosis, and 2 had cirrhosis. Overall mortality was 30% (n = 9). Median follow-up was 5 years (range, 0.25-13 years). One-year survival was similar among all 3 groups (P = .37), with a trend toward higher cumulative 5-year survival in Group 1 (100%). The majority of pediatric Fontan patients who underwent heart transplant demonstrated abnormal preoperative liver ultrasound findings. Heterogeneous echotexture or nodularity detected on U/S frequently indicates underlying liver parenchymal abnormalities. The presence of severe liver abnormalities was not associated with higher early mortality post-heart transplant in pediatric Fontan patients; however, late outcomes must be further elucidated.