Fontan-associated liver disease: Spectrum of US findings

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.

Fontan-Associated Liver Disease: A Review

Fontan-associated liver disease (FALD) is a chronic complication of the Fontan procedure, a palliative surgery for patients with congenital heart disease that results in a single-ventricle circulation. The success of the Fontan procedure has led to a growing population of post-Fontan patients living well into adulthood. For this population, FALD is a major cause of morbidity and mortality. It encompasses a spectrum of hepatic abnormalities, ranging from mild fibrosis to cirrhosis and hepatocellular carcinoma. The pathophysiology of FALD is multifactorial, involving hemodynamic and inflammatory factors. The diagnosis and monitoring of FALD present many challenges. Conventional noninvasive tests that use liver stiffness as a surrogate marker of fibrosis are unreliable in FALD, where liver stiffness is also a result of congestion due to the Fontan circulation. Even invasive tissue sampling is inconsistent due to the patchy distribution of fibrosis. FALD is also associated with both benign and malignant liver lesions, which may exhibit similar imaging features. There is therefore a need for validated diagnostic and surveillance protocols to address these challenges. The definitive treatment of end-stage FALD is also a subject of controversy. Both isolated heart transplantation and combined heart-liver transplantation have been employed, with the latter becoming increasingly preferred in the US. This article reviews the current literature on the epidemiology, pathophysiology, diagnosis, and management of FALD, and highlights knowledge gaps that require further research.

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.

Imaging of Fontan-Associated Liver Disease

ABSTRACT

The Fontan procedure is the definitive treatment for patients with single-ventricle physiology. Surgical advances have led to a growing number of patients surviving into adulthood. Fontan-associated liver disease (FALD) encompasses a spectrum of pathologic liver changes that occur secondary to altered physiology including congestion, fibrosis, and the development of liver masses. Assessment of FALD is difficult and relies on using imaging alongside of clinical, laboratory, and pathology information. Ultrasound, computed tomography, and magnetic resonance imaging are capable of demonstrating physiologic and hepatic parenchymal abnormalities commonly seen in FALD. Several novel imaging techniques including magnetic resonance elastography are under study for use as biomarkers for FALD progression. Imaging has a central role in detection and characterization of liver masses as benign or malignant. Benign FNH-like masses are commonly encountered; however, these can display atypical features and be mistaken for hepatocellular carcinoma (HCC). Fontan patients are at elevated risk for HCC, which is a feared complication and has a poor prognosis in this population. While imaging screening for HCC is widely advocated, no consensus has been reached regarding an optimal surveillance regimen.

EASL-ERN position paper on liver involvement in patients with Fontan-type circulation

Fontan-type surgery is the final step in the sequential palliative surgical treatment of infants born with a univentricular heart. The resulting long-term haemodynamic changes promote liver damage, leading to Fontan-associated liver disease (FALD), in virtually all patients with Fontan circulation. Owing to the lack of a uniform definition of FALD and the competitive risk of other complications developed by Fontan patients, the impact of FALD on the prognosis of these patients is currently debatable. However, based on the increasing number of adult Fontan patients and recent research interest, the European Association for The Study of the Liver and the European Reference Network on Rare Liver Diseases thought a position paper timely. The aims of the current paper are: (1) to provide a clear definition and description of FALD, including clinical, analytical, radiological, haemodynamic, and histological features; (2) to facilitate guidance for staging the liver disease; and (3) to provide evidence- and experience-based recommendations for the management of different clinical scenarios.

Transient liver elastography in the follow-up of Fontan patients: results of a nation wide survey in Germany

Introduction

Fontan-palliated patients are at risk for the development of Fontan-associated liver disease (FALD). Currently, there is no consensus on how to stage FALD. Transient elastography (TE) is a rapid, non-invasive method to assess FALD and liver fibrosis.

Method

To assess the availability and conditions of using TE to monitor liver disease in Fontan patients in german centers for pediatric cardiology and to propose the introduction of a standardized national protocol for the monitoring of liver disease, we developed a questionnaire.

Results

In total, 95 valid questionnaires were collected. Only 20% of the centers offer the TE investigation directly. Most of the centers transfer the patients to another department or center (40%) or didńt offer TE (40%). In only 2.6% of the centers TE is performed directly by the cardiologist. Most of the centers transfer the patients to a other department. In 29.2% TE is performed only at a certain age of the patients and in 27.7% it is performed if the patients present symptoms of failing Fontan. In only 13.9% of the centers TE is proposed in all the Fontan patients on a routine basis. Most often TE is performed only from the beginning of the adolescence. In the majority of answers it was not known if the patients are fasting for the examination (68%) or not and if the TE examination had to be performed in a specific breathing phase during TE (Inspiration/Expiration, 90%). In the majority, TE is not offered routinely (46.9%).

Discussion

To date in Germany, TE is only used in a few numbers of centers specialized in Fontan follow-up. A standardized protocol to use TE is currently not existing. With regard to the feasibility of the examination, it is evident that TE is a quick, cheap and easy method to distinguish between cases with and without progressive FALD. This makes TE a useful and prognostic tool for screening of liver disease and to failing Fontan circulation.

Conclusion

We propose a systematic TE evaluation of possible liver congestion and fibrosis, as a part of the routine follow-up of Fontan patients.

Fontan-associated Liver Disease in Adults: What a Cardiologist Needs to Know. A Comprehensive Review for Clinical Practitioners

Nowadays most patients with a univentricular heart after Fontan repair survive until adulthood. One of the hallmarks of Fontan circulation is permanently elevated central venous pressure, which leads to congestive hepatopathy. Subsequently, liver fibrosis, cirrhosis, or hepatocellular carcinoma may occur, all of them constituting an entity called Fontan-associated liver disease (FALD). Given that these complications convey poor prognosis, the need for life-long hepatic surveillance is not in doubt. Many serum biomarkers and sophisticated imaging techniques have been proposed to avoid invasive liver biopsy in this cohort, but none proved to be a relevant surrogate of liver fibrosis seen in histopathological specimens. The surveillance models proposed to date require an extensive diagnostic work-up, which can be problematic, particularly in resource-depleted countries. Moreover, the question of combined heart–liver transplant is gaining more attention in the Fontan cohort. The aim of this study is to provide practical information on the pathophysiology of FALD and to propose a simplified framework for the routine assessment of liver status in Fontan patients that would be helpful in the decision-making process.

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 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.

Hepatic and Renal Consequences of Single Ventricle Physiology Palliated with the Fontan Operation

Over time the long-term survival has dramatically increased for patients with complex congenital heart disease who undergo the Fontan operation. With this increased survival, it has become apparent that such a circulation has important consequences for other organ systems, particularly the liver and kidney. The adverse milieu created by chronic venous hypertension, low cardiac output and an inflammatory state contribute to the pathologic changes observed in the liver and kidneys over the long-term in Fontan patients. The clinical importance of these hepatic and renal comorbidities have only recently begun to be recognized in the context of increasing life expectancy in this population. The objectives of this review are: i) to provide an overview of the pathophysiology of the Fontan circulation and how liver and kidney disease evolve in this setting; ii) to summarize the current evidence base as it relates to the diagnostic approach to liver and kidney disease in Fontan patients; and, iii) to discuss the therapeutic approaches to Fontan associated liver and kidney disease. Given that this is a very active area of research in congenital heart disease, we have identified knowledge gaps and priority research areas to improve the care of Fontan patients. These include: i) establishing the optimal diagnostic tests to detect and track liver and kidney disease change over time,; ii) determining what treatable risk factors contribute to the development of liver and kidney disease; and, iii) evaluating therapies to prevent or slow progression of liver and kidney disease.

Complications and management of functional single ventricle patients with Fontan circulation: From surgeon's point of view

Fontan surgery by step-wise completing the isolation of originally mixed pulmonary and systemic circulation provides an operative approach for functional single-ventricle patients not amenable to biventricular repair and allows their survival into adulthood. In the absence of a subpulmonic pumping chamber, however, the unphysiological Fontan circulation consequently results in diminished cardiac output and elevated central venous pressure, in which multiple short-term or long-term complications may develop. Current understanding of the Fontan-associated complications, particularly toward etiology and pathophysiology, is extremely incomplete. What's more, ongoing efforts have been made to manage these complications to weaken the Fontan-associated adverse impact and improve the life quality, but strategies are ill-defined. Herein, this review summarizes recent studies on cardiac and non-cardiac complications associated with Fontan circulation, focusing on significance or severity, etiology, pathophysiology, prevalence, risk factors, surveillance, or diagnosis. From the perspective of surgeons, we also discuss the management of the Fontan circulation based on current evidence, including post-operative administration of antithrombotic agents, ablation, pacemaker implantation, mechanical circulatory support, and final orthotopic heart transplantation, etc., to standardize diagnosis and treatment in the future.

Non-invasive assessment of liver abnormalities in pediatric Fontan patients

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Heterogeneity of liver fibrosis in patients with congestive hepatopathy: A biopsy and explant comparison series

PURPOSE

Patients with end-stage heart failure and concomitant irreversible liver injury may be candidates for combined heart liver transplant (CHLT). Determining appropriate candidates for CHLT is essential given organ scarcity. Transjugular liver biopsy (TJLB) is used to evaluate the severity of parenchymal liver injury in transplant candidates. In patients with congestive hepatopathy (CH), the fibrosis pattern may be heterogenous.

METHODS

We reviewed all CHLT cases between 2007 and 2017, as well as lone-heart transplant cases with post-mortem autopsy. Pre-transplant TJLB was compared to explant to assess the performance of biopsy fibrosis staging.

RESULTS

12 patients were included. Median age at time of transplant was 58 and the cohort was predominantly male (75%). Seven (64%) TJLB were predominantly stage 4 fibrosis and 4 (36%) were stage 1. Advanced fibrosis was the dominant pattern in 7 (70%) explants and 5 (50%) explants had heterogenous fibrosis. In 50% of CH cases, there was discordance between the TJLB and explant. In the autopsy cases, the TJLB and autopsy findings differed.

CONCLUSIONS

In this series of matched TJLB and explanted livers, we found variable performance of TJLB in predicting the predominant fibrosis stage present in the liver.

Fontan-Associated Liver Disease: Pathophysiology, Staging, and Management

Fontan-associated liver disease is the term used to encompass the disorders arising from abnormal hemodynamic alterations and systemic venous congestion after the Fontan procedure. The histological changes produced in the liver are similar but not equivalent to those seen in other forms of cardiac liver disease. While the natural history of this form of liver disease is poorly established, many Fontan patients ultimately develop portal hypertension-related complications such as ascites, esophageal varices, malnutrition, and encephalopathy. Fontan survivors also show an elevated risk of hepatocellular carcinoma. Adequate staging of the liver damage is essential to anticipate screening strategies and improve global management.

Platelet count and abdominal dynamic CT are useful in predicting and screening for gastroesophageal varices after Fontan surgery

OBJECTIVE

Patients who undergo Fontan surgery for complex cardiac anomalies are prone to developing liver and gastrointestinal complications. In particular, gastroesophageal varices (GEVs) can occur, but their prevalence is unknown. We aimed to elucidate the occurrence of GEVs and the predicting parameters of GEVs in these patients.

MATERIALS AND METHODS

Twenty-seven patients (median age, 14.8 years; median time since surgery, 12.9 years) who had undergone the Fontan surgery and were examined by abdominal dynamic computed tomography (CT) for the routine follow-up were included in the study. Radiological findings including GEVs and extraintestinal complications were retrospectively evaluated by experienced radiologists in a blinded manner. Relationships between blood-biochemical and demographic parameters and the presence of GEVs were statistically analyzed.

RESULTS

Dynamic CT revealed gastric varices (n = 3, 11.1%), esophageal varices (n = 1, 3.7%), and gastrorenal shunts (n = 5, 18.5%). All patients with gastric varices had gastrorenal shunts. All gastric varices were endoscopically confirmed as being isolated and enlarged, with indications for preventive interventional therapy. A platelet count lower than 119 × 109 /L was identified as a predictor of GEV (area under the receiver operating curve, 0.946; sensitivity, 100%; and specificity, 87%).

CONCLUSIONS

GEVs are important complications that should not be ignored in patients who have undergone a Fontan procedure. Platelet counts lower than 119 × 109 /L may help to prompt patient screening by using abdominal dynamic CT to identify GEVs and their draining collateral veins in these patients.

Surveillance of Fontan Associated Liver Disease in Childhood and Adolescence

Fontan associated liver disease (FALD) has been recognized as a potentially serious sequela of the Fontan circulation. Prevalence of FALD among different age groups and risk factors for advanced changes were assessed. FALD screening included abdominal ultrasound and laboratory tests. A "liver disease score (LDS)" incorporating items from ultrasound and blood testing was calculated to grade FALD severity (5 items each, maximum score 10 points). 240 patients (male: n = 139, female: n = 101, systemic right ventricle: n = 160) underwent FALD screening 10 (IQR 7-15) years after Fontan surgery. Ultrasound was abnormal in 184 (76.6%) patients (surface nodularity / blunted liver edge: n = 133, 55.4%; heterogeneous parenchyma: n = 93, 38.8%; splenomegaly: n = 68, 28.3%; ascites: n = 23, 9.6%). At least one abnormal laboratory test was detected in 218 (90.8%) patients. Gamma-glutamyl-transpeptidase was elevated in the majority of patients (n = 206, 85.8%). Median LDS was 3 (2-4). Scores ≥5 were observed in 32 (13.3%) patients. Longer follow-up (15 (11-20) vs 9 (6-14) years, P <0.001), higher central venous (13 (11-15) vs 10 (9-12) mmHg, P <0.001) and end-diastolic pressure (8 (5-10) vs 6 (5-7) mmHg, P = 0.001), impaired ventricular function and absence of sinus rhythm were associated with LDS ≥5. Longer follow-up (OR 1.2 (1.1-1.3), P <0.001) and higher central venous pressure (OR 1.6 (1.3-2.1), p < 0.001) were the only independent predictors of advanced FALD. Abdominal ultrasound and laboratory abnormalities suggestive of FALD are common during routine follow-up already in childhood and adolescence irrespective of ventricular morphology. More advanced findings are associated with longer follow-up and higher central venous pressure.

Incidence, Predictors, and Mortality in Patients With Liver Cancer After Fontan Operation

Background

Liver cancer (LC) is a serious late complication after the Fontan operation. However, the incidence, predictors, and prognosis remain unknown. The purpose of our study was to determine these clinical characteristics.

Methods and Results

We assessed liver function in 339 consecutive patients who had undergone the Fontan procedure from 2005 to 2019. LC was histologically diagnosed in 10 patients after a median period of 2.9 years (range: 0.3–13.8; median age: 29.9 years [range: 14.4–41.5 years]; overall median post–Fontan procedure follow‐up: 25.6 years [range: 13–32.1 years]), and the annual incidence was 0.89%. Over the entire post‐Fontan follow‐up period, the annual incidences of new‐onset LC in the second, third, and fourth decades were 0.14%, 0.43%, and 8.83%, respectively. The patients with LC had longer follow‐up periods, higher levels of AFP (α‐fetoprotein), and higher values of liver fibrosis indices (P<0.01–0.0001). Moreover, all indices were predictive of new‐onset LC (P<0.01–0.0001). The LC treatments were surgical resection (n=3), transarterial chemoembolization (n=3), radiofrequency ablation (n=2), and hospice care (n=2). During a median follow‐up of 9.4 months, 4 patients died; the survival rate at 1 year was 60%, and it was better among asymptomatic patients (P<0.01).

Conclusions

The LC incidence rapidly increased ≥30 years after the Fontan procedure, and liver fibrosis indices and AFP were predictive of new‐onset LC. These LC‐predictive markers should be monitored closely and mandatorily for early LC detection and better prognosis.

Fontan-associated liver disease

OBJECTIVE

To review the pathophysiology of Fontan-associated liver disease, its histologic changes, and its radiologic manifestations.

CONCLUSIONS

Fontan-associated liver disease is the result of a set of structural and functional changes in the liver that occur secondary to hemodynamic changes brought about by Fontan surgery. The radiologic manifestations of Fontan-associated liver disease consist of changes in the size and shape of the liver, alterations in the signal intensity or pattern of enhancement, abnormalities in the vascular structures, and focal lesions, which include benign nodules with intense uptake in the arterial phase and hepatocellular carcinoma. Radiologists need to be familiar with this disease and its complications, because the number of patients who undergo Fontan surgery continues to increase, and these patients undergo an increasing number of imaging tests.

Fontan-associated liver disease and hepatocellular carcinoma in adults

The Fontan operation creates a unique circulation, and is a palliative therapy for patients with single-ventricle congenital heart disease. Increased venous pressure and decreased cardiac output and hepatic venous drainage result in sinusoidal dilatation around the central veins. This causes congestion and hypoxia in the liver, leading to Fontan-associated liver disease (FALD). Non-invasive and invasive markers enable diagnosis and evaluation of the fibrosis status in chronic liver disease; however, these markers have not been validated in FALD. Additionally, regenerative nodules such as focal nodular hyperplasia (FNH) are frequently found. The severity of fibrosis correlates with the duration of the Fontan procedure and the central venous pressure. Cirrhosis is a risk factor for hepatocellular carcinoma (HCC), the annual risk of which is 1.5–5.0%. HCC is frequently difficult to diagnose and treat because of cardiac complications, coagulopathy, and congenital abnormalities. The mortality rate of FALD with liver cirrhosis and/or FALD-HCC was increased to ~ 29.4% (5/17 cases) in a nationwide survey. Although there is no consensus on the surveillance of patients with FALD, serial monitoring of the alpha fetoprotein level and imaging at 6-month intervals is required in patients with cirrhosis.

Potential of Liver T1 Mapping for the Detection of Fontan-associated Liver Disease in Adults

Purpose:

The native T₁ value at 3T MRI is a sensitive marker for diffuse fibrosis or damage in various organs including the heart, liver, and pancreas. Despite the fact that Fontan-associated liver disease (FALD) is a crucial issue in adults with Fontan circulation, there are only a few studies with liver T₁ mapping in children and adolescents. We investigated the potential of the liver native T₁ mapping in detecting FALD in adult patients.

Methods:

We prospectively enrolled 16 consecutive adults with Fontan circulation (age 31.3 ± 8.5 years), who were in New York Heart Association Functional class II–IV. Twenty with tetralogy of Fallot (TOF), and 20 age-matched controls also underwent cardiac magnetic resonance (CMR) imaging at 3T. Myocardial T₁ mapping with a Modified Look-Locker Inversion recovery sequence was applied to liver T₁ mapping. Patients in the Fontan group underwent the right heart catheter and liver function tests, including those for fibrotic markers.

Results:

Liver native T₁ values in the Fontan group were significantly higher than that in TOF and controls (P < 0.001). In the Fontan group, the liver native T₁ value was significantly correlated with age, γ -glutamyltransferase, model for end-stage liver disease XI score, and albumin-bilirubin score (P = 0.01, 0.01, 0.044, 0.001). However, it demonstrated no correlation with central venous pressure, pulmonary vessel resistance, or fibrotic markers.

Conclusion:

Liver native T₁ value derived from CMR may be a non-invasive adjunctive and/or screening marker to detect FALD.

Fontan-Associated Liver Disease: Screening, Management, and Transplant Considerations

Surgical innovation and multidisciplinary management have allowed children born with univentricular physiology congenital heart disease to survive into adulthood. An estimated global population of 70 000 patients have undergone the Fontan procedure and are alive today, most of whom are <25 years of age. Several unexpected consequences of the Fontan circulation include Fontan-associated liver disease. Surveillance biopsies have demonstrated that virtually 100% of these patients develop clinically silent fibrosis by adolescence. As they mature, there are increasing reports of combined heart-liver transplantation resulting from advanced liver disease, including bridging fibrosis, cirrhosis, and hepatocellular carcinoma, in this population. In the absence of a transplantation option, these young patients face a poor quality of life and overall survival. Acknowledging that there are no consensus guidelines for diagnosing and monitoring Fontan-associated liver disease or when to consider heart transplantation versus combined heart-liver transplantation in these patients, a multidisciplinary working group reviewed the literature surrounding Fontan-associated liver disease, with a specific focus on considerations for transplantation.

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.

Risk of Liver Cirrhosis and Hepatocellular Carcinoma after Fontan Operation: A Need for Surveillance

Liver cirrhosis and hepatocellular carcinoma (HCC) are serious late complications that can occur after the Fontan procedure. This study aimed to investigate the cumulative incidence of cirrhosis and HCC and to identify specific features distinguishing HCC from benign arterial-phase hyperenhancing (APHE) nodules that developed after the Fontan operation. We retrospectively enrolled 313 post-Fontan patients who had been followed for more than 5 years and had undergone ultrasound or computed tomography (CT) of the liver between January 2000 and August 2018. Cirrhosis was diagnosed radiologically. The estimated cumulative incidence rates of cirrhosis at 5, 10, 20, and 30 years after the Fontan operation were 1.3%, 9.2%, 56.6%, and 97.9%, respectively. Multiphasic CT revealed that 18 patients had APHE nodules that were ≥1 cm in size and showed washout in the portal venous phase (PVP)/delayed phase, which met current noninvasive HCC diagnosis criteria. Among them, only seven patients (38.9%, 7/18) were diagnosed with HCC. After cirrhosis developed, the annual incidence of HCC was 1.04%. The appearance of washout in the PVP (p = 0.006), long time elapsed since the initial Fontan operation (p = 0.04), large nodule size (p = 0.03), and elevated serum α-fetoprotein (AFP) level (p < 0.001) were significantly associated with HCC. In conclusion, cirrhosis is a frequent late complication after Fontan operation, especially after 10 years, and HCC is not a rare complication after cirrhosis development. Diagnosis of HCC should not be based solely on the current imaging criteria, and washout on PVP and clinical features might be helpful to differentiate HCC nodules from benign APHE nodules.

Prevalence, features and predictive factors of liver nodules in Fontan surgery patients: The VALDIG Fonliver prospective cohort

BACKGROUND & AIMS

Fontan surgery is used to treat a variety of congenital heart malformations, and may lead to advanced chronic liver disease in the long-term. This study examines the prevalence, characteristics and predictors of liver nodules in patients following Fontan surgery.

METHODS

This was a prospective, cross-sectional, observational study conducted at 8 European centres. Consecutive patients who had undergone Fontan surgery underwent blood tests, abdominal ultrasonography (US), transient elastography (Fibroscan®), echocardiography, haemodynamic assessments, and abdominal MRI/CT scan. The primary outcome measure was liver nodules detected in the MRI/CT scan. Predictors of liver nodules were identified by multivariate logistic regression.

RESULTS

One hundred and fifty-two patients were enrolled (mean age 27.3 years). The mean time elapsed from surgery to inclusion was 18.3 years. Liver nodule prevalences were 29.6% (95% CI 23-37%) on US and 47.7% (95% CI 39-56%) on MRI/CT. Nodules were usually hyperechoic (76.5%), round-shaped (>80%), hyperenhancing in the arterial phase (92%) and located in the liver periphery (75%). The sensitivity and specificity of US were 50% (95% CI 38-62%) and 85.3% (95% CI 75-92%), respectively. Inter-imaging test agreement was low (adjusted kappa: 0.34). In the multivariate analysis, time since surgery >10 years was the single independent predictor of liver nodules (odds ratio 4.18; p = 0.040). Hepatocellular carcinoma was histologically diagnosed in 2 of the 8 patients with hypervascular liver nodules displaying washout.

CONCLUSION

While liver nodules are frequent in Fontan patients, they may go unnoticed in US. Liver nodules are usually hyperechoic, hypervascular and predominantly peripheral. This population is at risk of hepatocellular carcinoma, the diagnosis of which requires confirmatory biopsy.

LAY SUMMARY

Fontan surgery is the standard of care for many patients with univentricular congenital cardiopathies. Recent advances have improved the survival of Fontan patients, and nowadays most of them reach adulthood. In this setting, Fontan-associated liver disease (FALD) is increasingly recognised, and has become a significant prognostic factor. Liver nodules are considered a component of FALD yet their prevalence, imaging features and predictors have hardly been evaluated. In this study, we observed that liver nodules are frequent, typically hyperechoic, hypervascular and predominantly peripheral in patients with FALD. This population is at risk of hepatocellular carcinoma, the diagnosis of which must be confirmed by biopsy.

Visual liver assessment using Gd-EOB-DTPA-enhanced magnetic resonance imaging of patients in the early post-Fontan period

No imaging modality can be used to evaluate Fontan-associated liver disease (FALD). We retrospectively reviewed hepatic gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) characteristics of patients within 1 year post-Fontan procedure, and we evaluated the association between hepatic imaging abnormalities and clinical parameters, including follow-up cardiac catheterization and laboratory test findings. The EOB-MR images were graded, based on the extent of the decreased enhancement, as “normal” (Grade 1), “segmental” (Grade 2), “regional” (Grade 3), and “diffuse” (Grade 4). We enrolled 37 patients (mean age, 3.5 ± 1.0 years): 9 patients had Grade 1 or 2; 14 patients, Grade 3; and 14 patients, Grade 4. EOB-MRI revealed characteristic reticular or mosaic patterns of diminished enhancement (i.e. “frog spawn” appearance). Ultrasonography did not detect diminished enhancement or “frog spawn” appearance. A trend existed toward increased grade severity in imaging with increased central venous pressure, pulmonary vascular resistance, and gamma-glutamyltransferase levels. Noninvasive EOB-MRI revealed the characteristic pattern of diminished enhancement, which was correlated with certain clinical parameters indicative of Fontan physiology and liver dysfunction. Early-stage FALD may occur soon after the Fontan procedure and is associated with increased pressure in the inferior vena cava and hepatic veins.

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.

Hepatic pathology in patients after Fontan operation: A computed tomography imaging study

BACKGROUND

Hepatic dysfunction is an important long-term complication in Fontan patients. The purpose of this study was to evaluate the hepatic computed tomography (CT) findings after Fontan surgery and identify their association with clinical parameters.

METHODS

This study recruited 43 patients (23 male and 20 female patients aged 15.3 ± 6.8 years), who underwent Fontan surgery. Medical records were reviewed to collect their age, sex, congenital heart disease type, date of Fontan surgery, laboratory data, and hepatic CT findings. The relationship between hepatic findings and clinical parameters was analyzed.

RESULTS

The follow-up duration was 6.8 ± 4.1 years. Abnormal hepatic parenchymal enhancement was observed in 77% of the patients, with mild degree in 18, moderate degree in 10, and severe degree in 5 patients. According to the univariate analysis, risk factors for hepatic parenchymal enhancement were follow-up duration (odds ratio [OR]: 1.354 [95% confidence interval (CI): 1.024-2.078]; p = 0.042), hypoplastic left heart syndrome (HLHS) (OR: 3.262 [95% CI: 1.145-5.628]; p = 0.002), mean pulmonary artery pressure (OR: 1.598 [95% CI: 1.089-2.132]; p = 0.026), pulmonary vascular resistance index (OR: 1.263 [95% CI: 1.068-1.245]; p = 0.032), and brain natriuretic peptide (OR: 1.956 [95% CI: 1.085-2.673]; p = 0.045). According to the multivariate analysis, only HLHS (OR: 3.856 [95% CI: 1.389-5.863]; p = 0.001), mean pulmonary artery pressure (OR: 1.846 [95% CI: 1.362-2.549]; p = 0.015), and pulmonary vascular resistance index (OR: 1.185 [95% CI: 1.042-1.736]; p = 0.047) were significant risk factors for abnormal parenchymal enhancement.

CONCLUSION

Abnormal hepatic parenchymal enhancement detected through CT is common in Fontan patients. Regular liver function test in conjunction with imaging studies may be considered when following up Fontan patients.

Non-invasive assessment of liver alterations in Senning and Mustard patients

Background

Adults with congenital heart disease and ventricular dysfunction are prone to liver congestion, leading to fibrosis or cirrhosis but little is known about the prevalence of liver disease in atrial switch patients. Liver impairment may develop due to increased systemic venous pressures. This prospective study aimed to assess non-invasively hepatic abnormalities in adults who underwent Senning or Mustard procedures.

Methods

Hepatic involvement was assessed non-invasively clinically by laboratory analysis, hepatic fibrotic markers, sonography, and liver stiffness measurements [transient elastography (TE) and acoustic radiation force impulse imaging (ARFI)].

Results

Overall, 24 adults who had undergone atrial switch operation (13 Senning, 11 Mustard; four female; median age 27.8 years; range 24-45 years) were enrolled. In liver stiffness measurements, only three patients had values within the normal reference. All other patients showed mild, moderate or severe liver fibrosis or cirrhosis, respectively. Using imaging and laboratory analysis, 71% of the subjects had signs of liver fibrosis (46%) or cirrhosis (25%).

Conclusions

Non-invasive screening for liver congestion, fibrosis or cirrhosis could be meaningful in targeted screening for hepatic impairment in patients with TGA-ASO. As expert knowledge is essential, patients should be regularly controlled in highly specialised centres with cooperations between congenital cardiologists and hepatologists.

Hypoplastic left heart syndrome: From bedside to bench and back

Hypoplastic Left Heart Syndrome (HLHS) is a complex Congenital Heart Disease (CHD) that was almost universally fatal until the advent of the Norwood operation in 1981. Children with HLHS who largely succumbed to the disease within the first year of life, are now surviving to adulthood. However, this survival is associated with multiple comorbidities and HLHS infants have a higher mortality rate as compared to other non-HLHS single ventricle patients. In this review we (a) discuss current clinical challenges associated in the care of HLHS patients, (b) explore the use of systems biology in understanding the molecular framework of this disease, (c) evaluate induced pluripotent stem cells as a translational model to understand molecular mechanisms and manipulate them to improve outcomes, and (d) investigate cell therapy, gene therapy, and tissue engineering as a potential tool to regenerate hypoplastic cardiac structures and improve outcomes.

Forns Index is a predictor of cardiopulmonary bypass time and outcomes in Fontan conversion

Recent reports suggested that cardiopulmonary bypass (CPB) time is one of the risk factors for postoperative complications after Fontan conversion. Although Fontan conversion may be performed for the patients with hepatic fibrosis after initial Fontan procedure, there is no predictive indicator regarding the liver function associated with hemostasis which can affects CPB time. Thirty-one patients who underwent Fontan conversion using the same surgical procedure (extracardiac conduit conversion with right atrium exclusion) were enrolled. In multivariate analyses including age at Fontan conversion, interval from initial Fontan to conversion, hemodynamic data such as right atrial pressure, ventricular end-diastolic pressure, and cardiac index, hepatic data such as platelet count, prothrombin time international normalized ratios, serum total bilirubin, hyaluronic acid levels, five known indices for hepatic fibrosis (Forns Index, APRI, FIB4, FibroIndex, and MELD-XI), and liver stiffness measured by ultrasound elastography, only the Forns Index remained independently associated with the CPB time (P < 0.01) and blood transfusions (plasma transfusions and platelet concentrations: P < 0.01 for both). The cutoff level for Forns Index to predict the prolonged CPB time (exceeding 240 min) was 4.85 by receiver-operating characteristic curve (area under the curve 0.823, sensitivity 76.9%, and specificity 72.2%). Three patients with Forns Index > 7.0 had poor outcomes with long CPB time and massive blood transfusions in contrast with the other 28 patients. In conclusion, Forns Index could serve as a practical predictor of CPB time and is associated with blood transfusion volume in Fontan conversion.

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.

Identification of liver fibrosis using the hepatic vein waveform in patients with Fontan circulation

AIM

Liver fibrosis caused by congestive hepatopathy has emerged as an important complication after Fontan procedure. We evaluated the utility of the hepatic vein (HV) waveform using Doppler ultrasound for identification of liver fibrosis in Fontan patients.

METHODS

We investigated the HV waveforms in 41 Fontan patients and assessed correlations with clinical parameters, liver fibrosis markers, and hemodynamic data.

RESULTS

Based on our preliminary analysis of 64 adult patients with chronic liver disease who underwent liver biopsy, we classified HV waveforms into five types with reference to the degree of flattening (from type 1, normal triphasic waveform; to type 5, a monophasic waveform indicating cirrhosis), and confirmed a significant correlation between waveform pattern and fibrosis stage. Notably, we detected HV waveforms in all of the Fontan patients and classified them into five types. The HV waveform pattern positively correlated with γ-glutamyl transferase and hyaluronic acid levels, and negatively correlated with albumin level and platelet count, but did not correlate with central venous pressure or brain natriuretic peptide level, suggesting that HV waveform could reflect pathophysiological changes in the liver without being affected by hepatic congestion. The highest area under the receiver operating characteristic curve of the HV waveform for detecting advanced liver fibrosis, as defined by ultrasonic findings and clinical features, was 0.829 (81.8% sensitivity, 73.3% specificity), which was higher than that of other non-invasive fibrosis markers.

CONCLUSIONS

Hepatic vein waveforms change in accordance with liver fibrosis progression in Fontan patients, and can be a useful indicator of liver fibrosis after the Fontan procedure.

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.

Assessment of Advanced Liver Fibrosis and the Risk for Hepatic Decompensation in Patients With Congestive Hepatopathy

Congestive hepatopathy (CH) arises from chronically elevated right-sided heart pressures transmitted to the liver by passive venous congestion. Over time, CH can lead to hepatic bridging fibrosis, decompensated cirrhosis, and hepatocellular carcinoma. Currently, there are no evidence-based guidelines to direct appropriate screening or management of patients with CH, partly because of the inability of current clinical tools (serum tests, imaging studies, liver stiffness measurements, and liver biopsy) to accurately estimate hepatic fibrosis or the risk for hepatic decompensation. The Model for End-Stage Liver Disease excluding international normalized ratio (MELD-XI) score is the only validated serum-based test to predict clinical outcomes in CH. Noninvasive liver stiffness measurements are proving to be of minimal utility as all patients with CH have elevated values that currently cannot differentiate between congestion and fibrosis. In addition, fibrosis staging by liver biopsy is difficult to standardize because of heterogeneous collagen deposition in CH. Moreover, liver biopsy results have little predictive value for post-heart transplant hepatic outcomes in patients with CH. Evaluating liver nodules and masses is also complicated in CH as the finding of delayed venous washout in nodules is not specific for hepatocellular carcinoma in the background of a congested liver, and these lesions may require biopsy to confirm the diagnosis. The lack of effective clinical tools for predicting liver fibrosis and liver function suggests the need for the development of novel biomarkers in patients with CH to assist in the management of this complicated disease. (Hepatology 2018; 00:000-000).

Imaging Assessment of Hepatic Changes after Fontan Surgery

The aim of this study was to evaluate hepatic dysfunction over 10 years following Fontan surgery. We assessed the clinical usefulness of diagnostic tools for the detection and follow-up of hepatic dysfunction in patients with Fontan circulation.A total of 26 post-Fontan patients (median age 13 years, range 10-35 years; median duration from Fontan procedure 10.5 years, range 4-17 years) were enrolled in this study. Hepatic assessment was performed by ultrasonography, computed tomography (CT), and transient elastography (TE) with biochemical tests, echocardiography, and cardiac catheterization. Related parameters were compared on the basis of different findings in liver sonography, CT, and TE.Liver CT and TE showed abnormal findings in all patients. Liver ultrasonography revealed abnormal results in 24 patients (92.3%). However, liver function test was normal and did not correlate with imaging studies. C-reactive protein was significantly correlated with severity of CT findings. White blood cell, platelet count, and N-terminal pro-brain natriuretic peptide were correlated with severity on TE. Post-Fontan high pulmonary vascular resistance (P = 0.046) and high mean pulmonary artery pressure (P = 0.046) correlated with hepatic changes on liver CT.Changes in the liver post-Fontan surgery are common and occur even after 10 years the procedure. Liver imaging is more sensitive, and CT seems to be more useful for differentiation of severe hepatic changes.

Abdominal imaging findings in adult patients with Fontan circulation

Abstract

The Fontan procedures, designed to treat paediatric patients with functional single ventricles, have markedly improved the patient’s survival into adulthood. The physiology of the Fontan circuit inevitably increases systemic venous pressure, which may lead to multi-system organ failure in the long-term follow-up. Fontan-associated liver disease (FALD) can progress to liver cirrhosis with signs of portal hypertension. Focal nodular hyperplasia-like nodules commonly develop in FALD. Imaging surveillance is often performed to monitor the progression of FALD and to detect hepatocellular carcinoma, which infrequently develops in FALD. Other abdominal abnormalities in post-Fontan patients include protein losing enteropathy and pheochromocytoma/paraganglioma. Given that these abdominal abnormalities are critical for patient management, it is important for radiologists to become familiar with the abdominal abnormalities that are common in post-Fontan patients on cross-sectional imaging.

Teaching points

• Fontan procedure for functional single ventricle has improved patient survival into adulthood.

• Radiologists should be familiar with unique imaging findings of Fontan-associated liver disease.

• Focal nodular hyperplasia-like nodules commonly develop in Fontan-associated liver disease.

• Hepatocellular carcinoma, protein-losing enteropathy, pheochromocytoma/paraganglioma may develop.

Electronic supplementary material

The online version of this article (10.1007/s13244-018-0609-2) contains supplementary material, which is available to authorized users.

Fontan-Associated Liver Disease: A Review

Fontan-associated liver disease is a hepatic disorder arising from hemodynamic changes and systemic venous congestion following Fontan surgery. The histological changes produced in the liver are similar but not equivalent to those seen in other forms of cardiac liver disease. While the natural history of this form of liver disease is not well established, over time many Fontan patients develop portal hypertension-related complications such as ascites, variceal hemorrhage or encephalopathy. Fontan survivors also show an increased risk of hepatocellular carcinoma. Early diagnosis of advanced liver disease is mandatory for the prevention and treatment of complications such as hepatocellular carcinoma, esophageal varices and malnutrition. This review updates current knowledge of the pathophysiology and management of Fontan-associated liver disease including new diagnostic methods and treatments.

Fontan-associated Liver Disease

Fontan-associated liver disease refers to the disturbance in the liver secondary to hemodynamic changes and systemic venous congestion following Fontan surgery. Although the natural history of this disease has not yet been established, patients with more advanced liver injury develop the complications of portal hypertension, such as ascites, variceal haemorrhage, or encephalopathy. Moreover, patients with Fontan surgery may have an increased risk of hepatocellular carcinoma. Periodic liver monitoring is essential to prevent this disease and provide early treatment of liver complications.

Vortex Flow in the Right Atrium Surrogates Supraventricular Arrhythmia and Thrombus After Atriopulmonary Connection-Type Fontan Operation: Vortex Flow Analysis Using Conventional Cine Magnetic Resonance Imaging

We developed a novel imaging technique, designated as vortex flow (VF) mapping, which presents a vortex flow visually on conventional two-dimensional (2D) cine MRI. Using it, we assessed circumferential VF patterns and influences on RA thrombus and supraventricular tachycardia (SVT) in AP connection-type Fontan circulation. Retrospectively, we enrolled 27 consecutive patients (25.1 ± 9.2 years) and 7 age-matched controls who underwent cardiac MRI. Conventional cine images acquired using a 1.5-Tesla scanner were scanned for axial and coronal cross section of the RA. We developed "vortex flow mapping" to demonstrate the ratio of the circumferential voxel movement at each phase to the total movement throughout a cardiac cycle towards the RA center. The maximum ratio was used as a magnitude of vortex flow (MVF%) in RA cine imaging. We also measured percentages of strong and weak VF areas (VFA%). Furthermore, in 10 out of 27, we compared VF between previous CMR (3.8 ± 1.5 years ago) and latest CMR. Of the patients, 15 had cardiovascular complications (Group A); 12 did not (Group B). A transaxial image showed that strong VFA% in Group A was significantly smaller than that in Group B or controls. A coronal view revealed that strong VFA% was also smaller, and weak VFA% was larger in Group A than in Group B or controls (P < 0.05, and P < 0.05). Maximum MVF% in Group A was significantly smaller than in other groups (P < 0.001). Univariate logistic analyses revealed weak VFA% on a coronal image, and serum total bilirubin level as factors affecting cardiovascular complications (Odds ratio 1.14 and 66.1, 95% CI 1.004-1.30 and 1.59-2755.6, P values < 0.05 and < 0.05, respectively). Compared to the previous CMR, smaller maximum VMF%, smaller strong VFA%, and larger weak VFA% were identified in the latest CMR. Circumferentially weak VFA% on a coronal image can be one surrogate marker of SVT and thrombus in AP connection-type Fontan circulation. This simple VF assessment is clinically useful to detect blood stagnation.

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.