The precarious state of the liver after a Fontan operation: summary of a multidisciplinary symposium

Isosorbide DiNitrate Effect on Hemodynamic Profile, Liver Stiffness, and Exercise Tolerance in Fontan Circulation (The NEET Clinical Trial)

After Fontan operation, decreased venous capacitance and venoconstriction are adaptive mechanisms to maintain venous return and cardiac output. The consequent higher venous pressure may adversely impact end-organ function, exercise capacity and result in worse clinical outcomes. This pilot study evaluated the safety and effect of isosorbide dinitrate (ISDN), a venodilator, on exercise capacity, peripheral venous pressure (PVP), and liver stiffness in patients with Fontan circulation. In this prospective single-arm trial, 15 individuals with Fontan circulation were evaluated at baseline and after 4 weeks of therapeutic treatment with ISDN. Primary aims were to assess the safety of ISDN and the effect on maximal exercise. We also aimed to evaluate the effect of ISDN on ultrasound-assessed liver stiffness, markers of submaximal exercise, and PVP at rest and peak exercise. Repeated measures t-tests were used to assess change in variables of interest in response to ISDN. Mean age was 23.5 ± 9.2 years (range 11.2-39.0 years), and 10/15 (67%) were male. There was no statistically significant change in peak VO2 (1401 ± 428 to 1428 ± 436 mL/min, p = 0.128), but VO2 at the anaerobic threshold increased (1087 ± 313 to 1115 ± 302 mL/min, p = 0.03). ISDN was also associated with a lower peak exercise PVP (22.5 ± 4.5 to 20.6 ± 3.0 mmHg, p = 0.015). Liver stiffness was lower with ISDN, though the difference was not statistically significant (2.3 ± 0.4 to 2.1 ± 0.5 m/s, p = 0.079). Of the patients completing the trial, mild headache was common (67%), but there were no major adverse events. Treatment with ISDN for 4 weeks is well-tolerated in patients with a Fontan circulation. ISDN is associated with an increase in VO2 at anaerobic threshold, lower peak PVP, and a trend toward lower liver stiffness. Larger, longer duration studies will be necessary to define the impact of ISDN on clinical outcomes in the Fontan circulation.Clinical Trial Registration: URL: https://clinicaltrials.gov . Unique identifier: NCT04297241.

Robot-assisted laparoscopic hepatectomy for hepatocellular carcinoma with Fontan-associated liver disease: a world-first case report

BACKGROUND

Fontan-associated liver disease (FALD) encompasses hepatic complications following the Fontan procedure, ranging from fibrosis to hepatocellular carcinoma (HCC). Despite advancements in surgical techniques and perioperative care, robot-assisted laparoscopic hepatectomy (RALH) for HCC in patients with FALD has not been previously reported owing to concerns about the Fontan circulation.

CASE PRESENTATION

We present the first case of RALH for recurrent HCC in a 45-year-old man after the Fontan procedure. The preoperative evaluation confirmed good cardiac function. The procedure involved meticulous monitoring and management of central venous pressure and was successfully completed with minimal blood loss. Postoperative recovery was uneventful. With thorough preoperative cardiac assessment and close collaboration between cardiologists and anesthesiologists, RALH can be safely performed in selected patients with FALD.

CONCLUSIONS

Even if a patient has a history of FALD, RALH can be safely performed in selected patients under appropriate conditions.

Cytokeratin-18 is Elevated Prior to Conventional Measures of Liver Disease in Fontan-Associated Liver Disease

The Fontan procedure is used to palliate complex forms of congenital heart disease. This results in adverse hepatic sequelae now known as Fontan-associated liver disease (FALD). Conventional laboratory measures of liver disease do not correlate well with FALD severity. Cytokeratin-18 (CK-18) is a measure of cell death and is sensitive in detecting other causes of liver disease. Our aim was to assess the use of a novel measure of liver disease, CK-18, in Fontan patients. This is a single-center, prospective, cross-sectional study of Fontan patients aged 8-21 years old. We performed ultrasound elastography, echocardiography, magnetic resonance imaging, and serum laboratory testing. Novel laboratory test CK-18 levels in Fontan subjects were compared to healthy age-matched controls. Thirteen Fontan patients were evaluated with a median age 15 years (10, 14), 4 Hypoplastic left heart syndrome, 11 were male, and 5 were symptomatic. Fontan patients had normal AST/ALT, but a significantly elevated liver stiffness by elastography (median 13.4 kPa). Hepatic stiffness by elastography was associated with diastolic-indexed (rho = 0.58, p = 0.04) ventricular volumes. Compared to 10 aged-matched controls, CK-18 was higher in the Fontan group-cleaved CK-18 protein (p < 0.01) and full CK-18 protein, (p = 0.02). CK-18 was positively associated with AST and ALT. Elevated CK-18 levels were found in Fontan patients compared to controls suggesting hepatic cell death even in these relatively healthy Fontan patients. CK-18 was elevated prior to changes in traditional testing. CK-18 may be a useful sensitive marker of liver disease in FALD.

Biomarkers of fibrosis and portal hypertension in Fontan-associated liver disease in children and adults

BACKGROUND

Fontan-associated liver disease (FALD) refers to structural and functional changes of the liver caused by the physiology of the Fontan palliation. Currently, liver biopsy is the gold standard to assess liver fibrosis of FALD.

AIM

Investigate biomarkers correlating with severity of liver biopsy fibrosis in FALD.

METHODS

A retrospective study of post-Fontan patients ≥ 10 years of age who underwent liver biopsy was conducted. Advanced liver disease (ALD) was defined as bridging fibrosis and/or cirrhosis on liver biopsy. AST-to-platelet ratio index (APRI), Fibrosis-4 (FIB-4) and Liver Stiffness Measurement (LSM) from FibroScan were used as non-invasive fibrosis scores.

RESULTS

Sixty-six patients (26/47; 55.3% adults and 13/19 children; 68.4%) had ALD on biopsy. ALD was associated with lower platelet count (151 vs. 198 K/uL, p = 0.003), higher APRI (0.64 vs. 0.32, p = 0.01), higher FIB-4 (0.64 vs. 0.32, p = 0.02). Liver fibrosis score correlated with APRI (0.34, p = 0.02) and FIB-4 (0.47, p = 0.001) in adults. LSM had a high sensitivity at 81.3% with 45.5% specificity at a cut-off 18.5 kPa.

CONCLUSIONS

APRI and FIB-4 had modest discrimination to identify adults with advanced liver disease, but not children, indicating that these values may be followed as a marker of FALD progression in older patients.

Outcomes of Esophageal Varices in Adults With Fontan Palliation and Liver Cirrhosis

Background

The purpose of this study was to define the risk and outcomes of esophageal varices in adults with Fontan palliation and liver cirrhosis undergoing esophagogastroduodenoscopy (EGD).

Method

The results of EGD, abdominal ultrasound, and liver biopsy, as well as clinic notes from the hepatologist, were reviewed to determine the diagnosis of cirrhosis and esophageal varices. The incidence of acute gastrointestinal bleeding complication was assessed among patients with esophageal varices using the time of EGD as the baseline.

Results

Of 149 patients with Fontan palliation and liver cirrhosis, the prevalence of esophageal varices at baseline EGD was 34% (51 of 149). Of 98 patients without esophageal varices at baseline EGD, 27 (27%) underwent subsequent EGD, of whom 11 showed a new diagnosis of esophageal varices. The incidence of a new diagnosis of esophageal varices was 9% per year. Of 62 patients with esophageal varices, 9 (15%) had acute gastrointestinal bleeding complications during 45 (37-62) months of follow-up, yielding an incidence of 5% per year. Of the 9 patients, 8 underwent EGD and variceal banding during the hospitalization for bleeding and 1 patient died of septicaemia. Of the 8 patients who survived to hospital discharge, 2 patients were readmitted for esophageal bleeding within 12 months from the index hospitalization. Higher hepatic vein wedge pressure and hepatic vein pressure gradient were associated with esophageal varices and bleeding complications.

Conclusions

In this selected sample of adults with Fontan palliation and liver cirrhosis, esophageal varices were relatively common, and patients with esophageal varices had risk of bleeding complications.

Single-cell multiomics guided mechanistic understanding of Fontan-associated liver disease

The Fontan operation is the current standard of care for single-ventricle congenital heart disease. Individuals with a Fontan circulation (FC) exhibit central venous hypertension and face life-threatening complications of hepatic fibrosis, known as Fontan-associated liver disease (FALD). The fundamental biology and mechanisms of FALD are little understood. Here, we generated a transcriptomic and epigenomic atlas of human FALD at single-cell resolution using multiomic snRNA-ATAC-seq. We found profound cell type-specific transcriptomic and epigenomic changes in FC livers. Central hepatocytes (cHep) exhibited the most substantial changes, featuring profound metabolic reprogramming. These cHep changes preceded substantial activation of hepatic stellate cells and liver fibrosis, suggesting cHep as a potential first "responder" in the pathogenesis of FALD. We also identified a network of ligand-receptor pairs that transmit signals from cHep to hepatic stellate cells, which may promote their activation and liver fibrosis. We further experimentally demonstrated that activins A and B promote fibrotic activation in vitro and identified mechanisms of activin A's transcriptional activation in FALD. Together, our single-cell transcriptomic and epigenomic atlas revealed mechanistic insights into the pathogenesis of FALD and may aid identification of potential therapeutic targets.

Cardiac MRI-Derived Inferior Vena Cava Cross-Sectional Area Correlates with Measures of Fontan-Associated Liver Disease

There is currently no clear consensus on screening techniques to evaluate the presence or severity of Fontan-associated liver disease (FALD). Cardiac MRI (CMR) is used routinely for post-Fontan surveillance, but CMR-derived measures that relate to the severity of FALD are not yet defined. This was a cross-sectional single-center study of post-Fontan patients who underwent a CMR. CMR exams were re-analyzed by a single pediatric cardiologist. Surrogates of FALD included Gamma-Glutamyl Transferase (GGT), Fibrosis-4 laboratory score (FIB-4), and imaging findings. Findings consistent with cirrhosis on liver ultrasound included increased liver echogenicity and/or nodularity. Statistical analyses were performed to investigate potential relationships between CMR parameters and markers of FALD. Sixty-one patients were included. A larger inferior vena cava cross-sectional area (IVC-CSA) indexed to height was significantly associated with a higher FIB-4 score (Spearman's ρ = 0.28, p = 0.04), a higher GGT level (Spearman's ρ = 0.40, p = 0.02), and findings consistent with cirrhosis on liver ultrasound (OR 1.17, 95% CI: (1.01, 1.35), p = 0.04). None of the other CMR parameters were associated with markers of FALD. A larger indexed IVC-CSA was associated with higher systemic ventricle end-diastolic pressure (EDP) on cardiac catheterization (Spearman's ρ = 0.39, p = 0.018) as well as older age (Spearman's ρ = 0.46, p =  < 0.001). Indexed IVC-CSA was the only CMR parameter that was associated with markers of FALD. This measure has the potential to serve as an additional non-invasive tool to improve screening strategies for FALD.

Arrhythmias in Adult Congenital Heart Disease Heart Failure

Heart failure and arrhythmias represent 2 major causes of mortality and morbidity in adults with congenital heart disease. Arrhythmias and heart failure are interdependent, and one may exacerbate the other. Treatment of one also has a positive impact on the other. Management approaches need to be multifaceted, including pharmacotherapy, optimization of hemodynamic status with catheter-based or surgical interventions, and specific management of arrhythmia with device or catheter ablation therapy.

Intrahepatic Transcriptomics Differentiate Advanced Fibrosis and Clinical Outcomes in Adults With Fontan Circulation

BACKGROUND

The molecular mechanisms underlying Fontan-associated liver disease (FALD) remain largely unknown.

OBJECTIVES

This study aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes.

METHODS

This retrospective cohort study included adults with the Fontan circulation. Baseline clinical, laboratory, imaging, and hemodynamic data as well as a composite clinical outcome (CCO) were extracted from medical records. Patients were classified into early or advanced fibrosis. RNA was isolated from formalin-fixed paraffin-embedded liver biopsy samples; RNA libraries were constructed with the use of an rRNA depletion method and sequenced on an Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were performed with the use of DESeq2 and Metascape.

RESULTS

A total of 106 patients (48% male, median age 31 years [IQR: 11.3 years]) were included. Those with advanced fibrosis had higher B-type natriuretic peptide levels and Fontan, mean pulmonary artery, and capillary wedge pressures. The CCO was present in 23 patients (22%) and was not predicted by advanced liver fibrosis, right ventricular morphology, presence of aortopulmonary collaterals, or Fontan pressures on multivariable analysis. Samples with advanced fibrosis had 228 upregulated genes compared with early fibrosis. Samples with the CCO had 894 upregulated genes compared with those without the CCO. A total of 136 upregulated genes were identified in both comparisons and were enriched in cellular response to cytokine stimulus or oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-β signaling pathway, and vasculature development.

CONCLUSIONS

Patients with FALD and advanced fibrosis or the CCO exhibited upregulated genes related to inflammation, congestion, and angiogenesis.

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.

The prognostic role of liver volumetry in Fontan patients

BACKGROUND AND HYPOTHESES

High venous pressures and associated hepatic congestion are important drivers for Fontan-associated liver disease. The prognostic significance of hepatomegaly as a marker of congestion however is not well defined and is further explored in this research study.

METHODS

Fontan patients who have had liver ultrasound scans were identified from the Prince Sultan Cardiac Centre Fontan Database and had their anatomic, surgical, clinical histories abstracted from the electronic medical records following institutional ethics approval. Liver volumes were determined retrospectively from reviewing individual US images, and these, divided into tertiles, were analysed in the context of the predefined endpoints of (i) Primary - death or heart or liver transplantation, or (ii) Secondary - combined endpoint of death, transplantation, arrhythmia, or protein-losing enteropathy.

RESULTS

Mean indexed liver volumes for the entire cohort (n = 199) were 1065.1 ± 312.1 ml/m2, range 387 to 2071 ml/m2. Patients with the largest liver volumes (highest tertile) were less likely to have a functioning fenestration compared to those in the lowest tertile 44% versus 56% p = 0.016 and experienced the highest burden of mortality and heart or heart-liver transplantation, p = 0.016, and were more likely to reach the composite endpoint of death, protein-losing enteropathy, arrhythmia, or transplantation, p = 0.010. Liver volumes had an overall predictive accuracy for the combined outcome of 61% (CI 53%, 67%, p = 0.009).

CONCLUSIONS

Liver volumetry may serve as a potentially important congestion biomarker for adverse outcomes after the Fontan operation.

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.

Intrahepatic transcriptomics differentiate advanced fibrosis and clinical outcomes in adults with the Fontan circulation

Background

The molecular mechanisms underlying Fontan associated liver disease (FALD) remain largely unknown. We aimed to assess intrahepatic transcriptomic differences among patients with FALD according to the degree of liver fibrosis and clinical outcomes.

Methods

This retrospective cohort study included adults with the Fontan circulation at the Ahmanson/UCLA Adult Congenital Heart Disease Center. Clinical, laboratory, imaging and hemodynamic data prior to the liver biopsy were extracted from medical records. Patients were classified into early (F1-F2) or advanced fibrosis (F3-F4). RNA was isolated from formalin-fixed paraffin embedded liver biopsy samples; RNA libraries were constructed using rRNA depletion method and sequencing was performed on Illumina Novaseq 6000. Differential gene expression and gene ontology analyses were carried out using DESeq2 and Metascape. Medical records were comprehensively reviewed for a composite clinical outcome which included decompensated cirrhosis, hepatocellular carcinoma, liver transplantation, protein-losing enteropathy, chronic kidney disease stage 4 or higher, or death.

Results

Patients with advanced fibrosis had higher serum BNP levels and Fontan, mean pulmonary artery and capillary wedge pressures. The composite clinical outcome was present in 23 patients (22%) and was predicted by age at Fontan, right ventricular morphology and presence of aortopulmonary collaterals on multivariable analysis. Samples with advanced fibrosis had 228 up-regulated genes compared to early fibrosis. Samples with the composite clinical outcome had 894 up-regulated genes compared to those without it. A total of 136 up-regulated genes were identified in both comparisons and these genes were enriched in cellular response to cytokine stimulus, response to oxidative stress, VEGFA-VEGFR2 signaling pathway, TGF-beta signaling pathway, and vasculature development.

Conclusions

Patients with FALD and advanced liver fibrosis or the composite clinical outcome exhibit up-regulated genes including pathways related to inflammation, congestion, and angiogenesis. This adds further insight into FALD pathophysiology.

Regional Elevation of Liver T1 in Fontan Patients

Background

Fontan-associated liver disease (FALD) is characterized by hepatic congestion and progressive hepatic fibrosis in patients with the Fontan operation. This condition is generally clinically silent until late, necessitating techniques for early detection. Liver T1 mapping has been used to screen for FALD, but without consideration of regional variations in T1 values.

Methods

Liver T1 measured with a liver-specific T1 mapping sequence (PROFIT1) in Fontan patients was compared with cohorts of patients with biventricular congenital heart disease (BiV-CHD) and controls with normal cardiac function and anatomy.

Results

Liver T1 was significantly elevated in the Fontan cohort (n = 20) compared with patients with BiV-CHD (n = 12) and controls (n = 9) (781, 678, and 675 milliseconds, respectively; P < 0.001), with a consistent pattern of significantly elevated T1 values in the peripheral compared with central liver regions (ΔT1 = 54, 2, and 11 milliseconds; P < 0.001). PROFIT1 also yielded simultaneous T2∗ maps and fat fraction values that were similar in all groups. Fontan liver T1 values were also significantly elevated as compared with BiV-CHD and controls as measured with the cardiac (modified Look-Locker inversion) acquisitions (728, 583, and 583 milliseconds, respectively; P < 0.001) and values correlated with PROFIT1 liver T1 (R = 0.87, P < 0.001).

Conclusions

Fontan patients have globally increased liver T1 values and consistent spatial variations, with higher values in the peripheral liver regions as compared with spatially uniform values in BiV-CHD and controls. The spatial patterns may provide insight into the progression of FALD. Liver T1 mapping studies should include uniform spatial coverage to avoid bias based on slice locations in this population.

Combined heart-liver transplantation practices survey in North America: Evaluation and organ listing practices

We conducted a web-based survey to characterize liver transplant (LT) evaluation and listing practices for patients being evaluated for combined heart-liver transplantation (CHLT), with a specific emphasis on patients with congenital heart disease (CHD), around transplant centers in North America. Very few protocols for liver evaluation and listing in patients undergoing combined heart-liver transplantation are published, and no guidelines currently exist on this topic. A subject of intense debate in the transplant community is the decision of which patients with CHD and liver disease benefit from CHLT compared with heart transplantation. A focus group from the American Society of Transplantation Liver-Intestine Community of Practice Education Subcommittee developed a web-based survey that included questions (1) respondee demographic information; (2) LT evaluation practices in CHLT; (3) liver organ listing practices in CHLT, and (4) 4 clinical vignettes with case-based scenarios in CHLT liver listings among CHD patients who underwent Fontan palliation. The survey was distributed to medical and surgical LT program directors of 47 centers that had completed at least 1 CHLT up to July 2021 in the US and the University of Toronto, Canada. The survey had an excellent 83% response rate (87% for centers that completed at least 1 CHLT in the past 5 y). Total 66.7% used transjugular liver biopsy with HVPG measurements, 30% used percutaneous liver biopsy with no consensus on the use of a fibrosis staging system, 95% mandated contrasted cross-sectional imaging, and 65% upper endoscopy. The following isolated findings evaluation mandated CHLT listing: isolated elevated HVPG (61.5%); the presence of portosystemic collaterals on imaging (67.5%); the endoscopic presence of esophageal or gastric varices (75%), and the presence of HCC (80%), whereas the majority of centers did not feel that the presence of isolated splenomegaly (100%), thrombocytopenia (81.6%), endoscopic findings of portal hypertensive gastropathy (66.7%), or highly sensitized patients (84.6%) justified CHLT. In our survey of North American centers that had performed at least 1 CHLT in the past 5 years, we observed heterogeneity in practices for both evaluation and listing protocols in these patients.

Evaluation of Portal, Splenic, and Hepatic Vein Flows in Children Undergoing Congenital Heart Surgery

OBJECTIVE

Little is known about changes in portal, splenic, and hepatic vein flow patterns in children undergoing congenital heart surgery. This study aimed to determine the characteristics of portal, splenic, and hepatic vein flow patterns using ultrasonography in children undergoing cardiac surgery.

DESIGN

Single-center, prospective observational study.

SETTING

Tertiary children's hospital, operating room.

PARTICIPANTS

Children undergoing cardiac surgery.

MEASUREMENT AND MAIN RESULTS

The authors obtained ultrasound data from the heart, inferior vena cava, portal, splenic, and hepatic veins before and after surgeries. In the biventricular group, which included children with atrial and ventricular septal defects and pulmonary stenosis (n = 246), the portal pulsatility index decreased from 38.7% to 25.6% (p < 0.001) after surgery. The preoperative portal pulsatility index was significantly higher in patients with pulmonary hypertension (43.3% v 27.4%; p < 0.001). In the single-ventricle group (n = 77), maximum portal vein flow velocities of Fontan patients were significantly lower (13.5 cm/s) compared with that of patients with modified Blalock-Taussig shunt (19.7 cm/s; p = 0.035) or bidirectional cavopulmonary shunt (23.1 cm/s; p < 0.001). The cardiac index was inversely correlated with the portal pulsatility index in the bidirectional cavopulmonary shunt and Fontan circulation. (β = -5.693, r² = 0.473; p = 0.001) The portal pulsatility index was correlated with splenic venous pulsatility and hepatic venous atrial reverse flow velocity in biventricular and single-ventricle groups.

CONCLUSIONS

The characteristics of venous Doppler patterns in the portal, splenic, and hepatic veins differed according to congenital heart disease. Further studies are required to determine the association between splanchnic venous Doppler findings and clinical outcomes in this population.

Hepatic Fibrosis Risk Factors in Extracardiac-Fontan Patients: Observations From a Single Center

Objective: We reviewed our experience with transvenous liver biopsy-derived hepatic fibrosis scores and possible associated risk factors in those postextracardiac Fontan patients. Methods: We identified extracardiac-Fontan patients with postoperative durations <20 years who underwent cardiac catheterizations with transvenous hepatic biopsies between April 2012 and July 2022. If a patient underwent two liver biopsies, we averaged the two total fibrosis scores and concurrent time, pressure, and oxygen saturation data. We grouped patients by the following factors: (1) sex, (2) venovenous collaterals, and (3) type of functionally univentricular heart. We identified potential hepatic fibrosis risk factors as the following: female, presence of venovenous collaterals, and a functional univentricle of right-ventricular type. For statistical analysis, we used Kruskal-Wallis nonparametric testing. Results: We identified 127 patients who underwent 165 transvenous biopsies, with 38 patients undergoing 2 biopsies. We found that females with two additional risk factors had the highest median total fibrosis scores, 4 (1-8); males with <2 risk factors had the lowest median total fibrosis scores, 2 (0-5); and females with <2 additional risk factors and males with two risk factors were in the middle, median total fibrosis score 3 (0-6), P =.002; and there were no statistical differences for the other demographic or hemodynamic variables. Conclusions: For extracardiac-Fontan patients with similar demographic and hemodynamic variables, identifiable risk factors are associated with the degree of hepatic fibrosis.

Fontan-associated liver disease: Diagnosis, surveillance, and management

The Fontan operation is a lifesaving procedure for patients with functional single-ventricle congenital heart disease, where hypoplastic left heart syndrome is the most frequent anomaly. Hemodynamic changes following Fontan circulation creation are now increasingly recognized to cause multiorgan affection, where the development of a chronic liver disease, Fontan-associated liver disease (FALD), is one of the most important morbidities. Virtually, all patients with a Fontan circulation develop liver congestion, resulting in fibrosis and cirrhosis, and most patients experience childhood onset. FALD is a distinctive type of congestive hepatopathy, and its pathogenesis is thought to be a multifactorial process driven by increased nonpulsatile central venous pressure and decreased cardiac output, both of which are inherent in the Fontan circulation. In the advanced stage of liver injury, complications of portal hypertension often occur, and there is a risk of developing secondary liver cancer, reported at young age. However, FALD develops with few clinical symptoms, a surprisingly variable degree of severity in liver disease, and with little relation to poor cardiac function. The disease mechanisms and modifying factors of its development are still not fully understood. As one of the more important noncardiac complications of the Fontan circulation, FALD needs to be diagnosed in a timely manner with a structured monitoring scheme of disease development, early detection of malignancy, and determination of the optimal time point for transplantation. There is also a clear need for consensus on the best surveillance strategy for FALD. In this regard, imaging plays an important role together with clinical scoring systems, biochemical workups, and histology. Patients operated on with a Fontan circulation are generally followed up in cardiology units. Ultimately, the resulting multiorgan affection requires a multidisciplinary team of healthcare personnel to address the different organ complications. This article discusses the current concepts, diagnosis, and management of FALD, with special emphasis on the role of different imaging techniques in the diagnosis and monitoring of disease progression, as well as current recommendations for liver disease surveillance.

Congenital Portosystemic Shunt Presenting As Hyperammonemia Following Fontan Operation

The Fontan operation allows survival for children with single ventricle congenital heart disease. In the acute postoperative period, perioperative insults and drastic changes in vascular pressures can potentially cause ischemic liver injury. We present a 3-year-old female with congenital heart disease presenting post-Fontan procedure complicated by altered mental status due to elevated ammonia levels. Etiology of the hyperammonemia was unknown and relatively controlled with medication. Further investigation, however, revealed a congenital portosystemic shunt. Congenital portosystemic shunts, more specifically Abernethy malformations, are rare conditions characterized as intrahepatic or extrahepatic, resulting in diversion of portal flow to systemic.

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.

T1 mapping of the myocardium and liver in the single ventricle population

BACKGROUND

Fontan associated liver disease (FALD) is an increasingly recognized complication of the single ventricle circulation characterized by hepatic venous congestion leading to hepatic fibrosis. Within the Fontan myocardium, fibrotic myocardial remodeling may occur and lead to ventricular dysfunction. Magnetic resonance imaging (MRI) T1 mapping can characterize both myocardial and liver properties.

OBJECTIVE

The aim of this study was to compare myocardial and liver T1 between single ventricle patients with and without a Fontan and biventricular controls.

MATERIALS AND METHODS

A retrospective study of 3 groups of patients: 16 single ventricle patients before Fontan (SV_pre 2 newborns, 9 pre-Glenn, 5 pre-Fontan, 31% single right ventricle [SRV]), 16 Fontans (56% SRV) and 10 repaired d-transposition of the great arteries (TGA). Native modified Look-Locker inversion T1 times were measured in the myocardium and liver. Cardiac MRI parameters, myocardial and liver T1 values were compared in the three groups. Correlations were assessed between liver T1 and cardiac parameters.

RESULTS

Myocardial T1 was higher in SV_pre (1,056 ± 48 ms) and Fontans (1,047 ± 41 ms) compared to TGA (1,012 ± 48 ms, P < 0.05). Increased liver T1 was found in both SV_pre (683 ± 82 ms) and Fontan (727 ± 49 ms) patients compared to TGA patients (587 ± 58 ms, P < 0.001). There was no difference between single left ventricle (SLV) versus SRV myocardial or liver T1. Liver T1 showed moderate correlations with myocardial T1 (r = 0.48, confidence interval [CI] 0.26-0.72) and ejection fraction (r = -0.36, CI -0.66-0.95) but not with other volumetric parameters.

CONCLUSION

Increased liver T1 at both pre- and post-Fontan stages suggests there are intrinsic liver abnormalities early in the course of single ventricle palliation. Increased myocardial T1 and its relationship to liver T1 suggest a combination of edema from passive venous congestion and/or myocardial fibrosis occurring in this population. Liver T1 may provide an earlier marker of liver disease warranting further study.

Hepatic fibrosis gender differences in extracardiac Fontan patients

OBJECTIVE

We investigated possible gender differences for hepatic fibrosis in extracardiac-Fontan patients.

METHODS

We identified extracardiac Fontan, performed between 2000 and 2016, who underwent cardiac catheterizations with transvenous hepatic biopsies between April 2012 and June 2022. We divided the patients by gender for analysis.

RESULTS

We identified 116 patients who underwent 145 transvenous biopsies, with 29 patients undergoing 2 biopsies at an average interval of 5 ± 1 years. We divided the 145 biopsies into two groups: 1) 98/145 (68%) males and 2) 47/145 (32%) females. For the 47 female liver biopsy specimens, the median total fibrosis score was 3 (0-8), and for the 98 male liver biopsy specimens, the median total fibrosis score was 2 (0-6), p = .007. The average age at surgery for females was 3 ± 1 years and for males 3 ± 1 years, p = .99. Average Fontan duration at biopsy for females was 11 ± 5 years and for males, 10 ± 4 years, p = .23. No other demographic, anatomic, echocardiographic, laboratory, or hemodynamic findings demonstrated statistically significant gender differences.

CONCLUSIONS

Females had statistically significantly higher median total fibrosis scores than males for the similar average age at extracardiac Fontan and average Fontan duration.

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.

Optimal Fenestration of the Fontan Circulation

In this paper, we develop a pulsatile compartmental model of the Fontan circulation and use it to explore the effects of a fenestration added to this physiology. A fenestration is a shunt between the systemic and pulmonary veins that is added either at the time of Fontan conversion or at a later time for the treatment of complications. This shunt increases cardiac output and decreases systemic venous pressure. However, these hemodynamic benefits are achieved at the expense of a decrease in the arterial oxygen saturation. The model developed in this paper incorporates fenestration size as a parameter and describes both blood flow and oxygen transport. It is calibrated to clinical data from Fontan patients, and we use it to study the impact of a fenestration on several hemodynamic variables, including systemic oxygen availability, effective oxygen availability, and systemic venous pressure. In certain scenarios corresponding to high-risk Fontan physiology, we demonstrate the existence of a range of fenestration sizes in which the systemic oxygen availability remains relatively constant while the systemic venous pressure decreases.

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.

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.

The absence of warfarin treatment and situs inversus are associated with the occurrence of hepatocellular carcinoma after Fontan surgery

BACKGROUND

Hepatocellular carcinoma (HCC) is a long-term complication of Fontan-associated liver disease (FALD). However, risk factors for HCC in patients with FALD remain unclear. This study aimed to identify factors associated with HCC development post-Fontan procedure.

METHODS

We retrospectively examined 103 post-Fontan patients who underwent hepatic imaging at our institution. HCC incidence and patient characteristics were analyzed. A Cox proportional hazards model was used to identify risk factors for HCC.

RESULTS

The median interval between Fontan surgery and final hepatic imaging was 19.6 (1.0-37.7) years. Among 103 patients, nine developed HCC. The cumulative incidence rates of HCC at 10, 20, and 30 years postoperatively were 0%, 7%, and 13%, respectively. In the univariate analysis, age at Fontan surgery, situs inversus, and warfarin absence were associated with HCC occurrence. The multivariate analysis identified the warfarin absence (adjusted hazard ratio [aHR], 22.71; 95% confidence interval: 3.29-507.1; p = 0.0005) and situs inversus (aHR, 14.36; 95% confidence interval: 2.75-105.5; p = 0.002) as risk factors. The prevalence of situs inversus and the warfarin absence was 12% and 50%, respectively. The 20- and 30-year incidence rates of HCC among patients who received warfarin were 0% and 7%, respectively, while those among patients who did not receive warfarin were 14% and 21%, respectively. HCC incidence was significantly higher in the non-warfarin group than in the warfarin group (p = 0.006) and among patients with situs inversus than among those with situs solitus (p = 0.004).

CONCLUSIONS

Warfarin absence and situs inversus were associated with HCC development post-Fontan procedure.

Morphologic Alterations Precede Functional Hepatic Impairment as Determined by 13C-Methacetin Liver Function Breath Test in Adult Fontan Patients

Objectives: Fontan-associated liver disease (FALD) is the most common end-organ dysfunction affecting up to 70–80% of the Fontan population. The clinical significance of FALD is incompletely understood and no unambiguous correlation between hepatic function and FALD severity has been established. In this study, we sought to evaluate maximal liver function capacity with liver maximum function capacity test (LiMAx®) in adult Fontan patients.

Methods: Thirty-nine adult Fontan patients (median age: 29.4 years [IQR 23.4; 37.4], median follow-up after Fontan operation: 23.9 years [IQR 17.8;26.4]) were analyzed in a cross-sectional observational study using LiMAx® test (Humedics GmbH, Berlin, Germany), laboratory testing, transient elastography (TE) and hepatic ultrasound. The LiMAx® test is based on the metabolism of ¹³C-methacetin, which is administered intravenously and cleaved by the hepatic cytochrome P4501A2 to paracetamol and ¹³CO₂, which is measured in exhaled air and correlates with maximal liver function capacity.

Results: Maximal liver function capacity assessed by LiMAx® test was normal in 28 patients (>315 μg/h^*kg) and mildly to moderately impaired in 11 patients (140–314 μg/h^*kg), while no patient displayed severe hepatic impairment (<139 μg/kg^*h). No correlation was found between maximal liver function capacity and hepatic stiffness by TE (r² = −0.151; p = 0.388) or the presence of sonographic abnormalities associated with FALD (r² = −0.204, p = 0.24). There was, however, an association between maximal liver function capacity and the laboratory parameters bilirubin (r² = −0.333, p = 0.009) and γ-glutamyl transferase (r² = −0.367; p = 0.021). No correlation was detected between maximal liver function capacity and the severity of FALD (r² = −0.235; p = 0.152).

Conclusion: To the best of our knowledge, this is the first study to evaluate maximal liver function capacity using LiMAx® test in Fontan patients, which is a useful complementary diagnostic instrument to assess chronic hepatic injury. Maximal liver function capacity was preserved in most of our adult Fontan patients despite morphologic evidence of FALD. Moreover, maximal liver function capacity does not correlate with the extent of FALD severity evaluated by sonography or laboratory analysis. Thus, the development and progression of FALD in Fontan patients is not a uniform process and diagnostics of chronic hepatic injury during follow-up should encompass various modalities.

A Path FORWARD: Development of a Comprehensive Multidisciplinary Clinic to Create Health and Wellness for the Child and Adolescent with a Fontan Circulation

Today, it is anticipated most individuals diagnosed with single-ventricle malformation will survive surgical reconstruction through a successful Fontan operation. As greater numbers of patients survive, so has the recognition that individuals with Fontan circulation face a variety of challenges. The goal of a normal quality and duration of life will not be reached by all. The hurdles fall into a variety of domains. From a cardiovascular perspective, the Fontan circulation is fundamentally flawed by its inherent nature of creating a state of chronically elevated venous pressure and congestion, accompanied by a relatively low cardiac output. Ventricular dysfunction, atrioventricular valve regurgitation, and arrhythmia may directly impact cardiac performance and can progress with time. Problems are not limited to the cardiovascular system. Fontan circulatory physiology impacts a multitude of biological processes and health parameters outside the heart. The lymphatic circulation is under strain manifesting as variable degrees of protein-rich lymph loss and immune system dysregulation. Organ system dysfunction develops through altered perfusion profiles. Liver fibrosis is ubiquitous, and a process of systemic fibrogenesis in response to circulatory stressors may affect other organs as well. Somatic growth and development can be delayed. Behavioral and mental health problems are common, presenting as clinically important levels of anxiety and depression. Most striking is the high variability in prevalence and magnitude of these complications within the population, indicating the likelihood of additional factors enhancing or mitigating their emergence. We propose that optimal care for the individual with single ventricle and a Fontan circulation is ideally offered in a comprehensive multidisciplinary manner, with attention to elements that are beyond cardiac management alone. In this report, we share the concepts, our experiences, and perspectives on development of a clinic model-the "Fontan rehabilitation, wellness and resilience development" or FORWARD program. We provide insights into the mechanics of our multidisciplinary model of care and the benefits offered serving our growing population of individuals with a Fontan circulation and their families.

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.

Non-contrast enhanced magnetic resonance imaging for characterization of Fontan associated liver disease

OBJECTIVES

To evaluate the ability of non-contrast enhanced magnetic resonance imaging (MRI) techniques to characterize Fontan associated liver disease (FALD) in adolescent and adult Fontan patients.

METHODS

Fontan patients (n = 29) and healthy controls (n = 13) underwent an MRI protocol with T₁, T₂ and Apparent Diffusion Coefficient (ADC) mapping. Routine FALD screening included abdominal ultrasound and laboratory testing.

RESULTS

Median follow-up after Fontan operation was 15.1 (IQR 12.0-16.8) years. Distinct differences in tissue characteristics were visualized. T₁ and T₂ relaxation times were prolonged in Fontan patients, particularly of the right lobe (T₁: 745 (IQR 715-784) ms vs. 586 (IQR 555-602) ms, p < 0.001; T₂: 63 (IQR 59-64) ms vs. 58 (IQR 56-60) ms, p = 0.002). Left lobe ADC was lower in Fontan patients (1.10 (IQR 1.06-1.18) x 10^-3 mm²/s vs. 1.23 (IQR 1.19-1.29) x 10^-3 mm²/s, p < 0.001). T₂ mapping was able to differentiate between controls and Fontan patients with different FALD severity. Right lobe T₂ was higher in patients with moderate or severe in comparison to those with no or mild changes and healthy controls (64 (IQR 61-67) ms vs. 60 (IQR 59-63) ms vs. 58 (IQR 56-60) ms, p = 0.001).

CONCLUSIONS

Non-contrast enhanced MRI methods are able to visualize regional differences in liver tissue characteristics. T₁ and T₂ relaxation times were prolonged in Fontan patients suggestive of fibrosis or congestive hepatopathy, while reduced ADC might reflect impaired microperfusion. These methods have promising clinical potential for detection of liver abnormalities in Fontan patients. The usefulness of T₂ mapping to grade FALD severity merits further investigation.

Liver fibrosis in patients with tetralogy of Fallot, an unrecognised complication?

OBJECTIVES

Improved survival has led to a growing population of adults with congenital heart disease (CHD), followed by numerous reports of late complications. Liver disease is a known complication in some patients, with most studies focusing on Fontan associated liver disease. Whether liver disease also exists in other patients with CHD is not fully investigated. Elevated central venous pressure is considered pivotal in the development of liver disease in Fontan associated liver disease, and other patients with alterations in central venous pressure may also be at risk for developing liver fibrosis. We wanted to see if liver fibrosis is present in patients with tetralogy of Fallot. Many patients with tetralogy of Fallot have severe pulmonary regurgitation, which can lead to elevated central venous pressure. Patients with tetralogy of Fallot may be at risk of developing liver fibrosis.

MATERIALS AND METHODS

Ten patients (24-56 years) with tetralogy of Fallot and pulmonary regurgitation were investigated for liver fibrosis. All patients were examined with magnetic resonance elastography of liver, hepatobiliary iminodiacetic acid scan, indocyanine green elimination by pulse spectrophotometry, elastography via FibroScan, abdominal ultrasound including liver elastography, and blood samples including liver markers.

RESULTS

Three out of ten patients had findings indicating possible liver fibrosis. Two of these had a liver biopsy performed, which revealed fibrosis stage 1 and 2, respectively. The same three patients had an estimated elevated central venous pressure in previous echocardiograms.

CONCLUSIONS

Mild liver fibrosis was present in selected patients with tetralogy of Fallot and may be related to elevated central venous pressure.

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.

Pediatric heart-liver transplant outcomes in the United States: A 25-year National Cohort Study

BACKGROUND

Pediatric HLT remains uncommon in the United States and criteria for HLT are unclear. The objectives of this study were to review the indications, and outcomes of pediatric HLT.

METHODS

Data from the Scientific Registry of Transplant Recipients heart and liver databases were used to identify 9245 pediatric isolated heart transplants (PHT), 14 134 pediatric isolated liver transplant (PLT), and 20 pediatric HLT (16 patients underwent sHLT [same organ donor] and four patients with a history of PHT followed by PLT [different organ donors]; age ≤21 years) between 1992 and 2017. Outcomes included patient survival, and 1-year rates of acute heart and liver rejection.

RESULTS

The median age for pediatric HLT was 15.6 (IQR: 10.5, 17.9) years, and included 12 males (12/20 = 60%). In the HLT group, the most common indication for HT was CHD (12/20 = 60%), and the most common indication for liver transplant was cirrhosis (9/20 = 45%). The 1, 3, and 5 year actuarial survival rates in pediatric simultaneous HLT recipients (n = 16) were 93%, 93%, and 93%, respectively, and was similar to isolated PHT alone (88%, 81%, and 75.5%, respectively and isolated PLT alone (84%, 82%, and 80%), respectively. There was no heart or liver rejection reported in the HLT group versus 9.9% in heart and 10.6% in liver transplant-only groups, respectively.

CONCLUSION

Pediatric HLT is an uncommon but acceptable option for recipients with combined end-organ failure, with intermediate survival outcomes comparable to those of single-organ recipients.

Non-invasive biomarkers of Fontan-associated liver disease

Background & Aims

Fontan-associated liver disease (FALD) has emerged as an important morbidity following surgical palliation of single ventricle congenital heart disease. In this study, non-invasive biomarkers that may be associated with severity of FALD were explored.

Methods

A retrospective cohort of paediatric patients post-Fontan who underwent liver biopsy at a high volume at a paediatric congenital heart disease centre was reviewed.

Results

Among 106 patients, 66% were male and 69% were Hispanic. The mean age was 14.4 ± 3.5 years, and biopsy was performed 10.8 ± 3.6 years post-Fontan. The mean BMI was 20.8 ± 5 kg/m², with 27.4% meeting obesity criteria. Bridging fibrosis was observed in 35% of patients, and 10.4% of all patients had superimposed steatosis. Bridging fibrosis was associated with lower platelet counts (168.3 ± 58.4 vs. 203.9 ± 65.8 K/μl for congestive hepatic fibrosis score [CHFS] 0–2b, p = 0.009), higher bilirubin (1.7 ± 2.2 vs. 0.9 ± 0.7 mg/dl, p = 0.0090), higher aspartate aminotransferase-to-platelet ratio index [APRI] and fibrosis-4 [FIB-4] scores (APRI: 0.5 ± 0.3 vs. 0.4 ± 0.1, p <0.01 [AUC: 0.69] and FIB-4: 0.6 ± 0.4 vs. 0.4 ± 0.2, p <0.01 [AUC: 0.69]), and worse overall survival (median 2 years follow-up post-biopsy, p = 0.027). Regression modelling of temporal changes in platelet counts before and after biopsy correlated with fibrosis severity (p = 0.005).

Conclusions

In this large, relatively homogeneous adolescent population in terms of age, ethnicity, and Fontan duration, bridging fibrosis was observed in 35% of patients within the first decade post-Fontan. Bridging fibrosis was associated with worse survival. Changes in platelet counts, even years before biopsy, and APRI/FIB-4 scores had modest discriminatory power in identifying patients with advanced fibrosis. Steatosis may represent an additional risk factor for disease progression in obese patients. Further prospective studies are necessary to develop strategies to screen for FALD in the adolescent population.

Lay summary

In this study, the prevalence of Fontan-associated liver disease (FALD) in the young adult population and clinical variables that may be predictive of fibrosis severity or adverse outcomes were explored. Several lab-based, non-invasive markers of bridging fibrosis in FALD were identified, suggesting that these values may be followed as a prognostic biomarker for FALD progression in the adolescent population.

•

FALD is universal within 10 years post-Fontan, with 35% of patients having bridging fibrosis.

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Of our adolescent patient population, 10% had concomitant hepatic steatosis, which was associated with obesity.

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Regression modelling demonstrates that temporal changes in platelet counts correlate with severity of fibrosis in FALD.

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AST-to-platelet ratio index and FIB-4 scores correlate with bridging fibrosis with a high specificity.

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Bridging fibrosis in FALD is associated with worse survival.

Successive perioperative management of laparoscopic liver resection in the reverse Trendelenburg position for a patient with Fontan physiology: a case report

BACKGROUND

Laparoscopic surgery for a patient with Fontan physiology is challenging because pneumoperitoneum and positive pressure ventilation could decrease venous return and the accumulated partial pressure of arterial carbon dioxide (PaCO₂) could increase pulmonary vascular resistance, which might lead to disruption of the hemodynamics.

CASE PRESENTATION

A 25-year-old man with Fontan physiology was scheduled to undergo laparoscopic liver resection for Fontan-associated liver disease (FALD) with noninvasive monitoring of cardiac output (CO) by transpulmonary thermodilution in addition to transesophageal echocardiography. The abdominal air pressure was maintained low, and we planned to switch to open abdominal surgery promptly if hemodynamic instability became apparent because of the accumulated PaCO₂ or postural change. Consequently, the pneumoperitoneum had limited influence on circulatory dynamics, but central venous pressure significantly decreased with postural change to the reverse Trendelenburg position. Laparoscopic liver resection for FALD was performed successfully with no significant changes in CO and central venous saturation.

CONCLUSIONS

With strict circulation management, laparoscopic surgery for a patient with Fontan physiology can be performed safely. Comprehensive hemodynamic assessment by noninvasive transpulmonary thermodilution can provide valuable information to determine the time for shift to open abdominal surgery.

Spectrum of Fontan-associated liver disease assessed by MRI and US in young adolescents

Purpose

Patients with Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. The mechanisms and disease development are unclear and early secondary liver cancer is a concern. This study will describe hepatic imaging findings in a national cohort of adolescents with Fontan circulation.

Methods

The patients prospectively underwent abdominal contrast enhanced magnetic resonance imaging (MRI) including diffusion-weighted imaging. Images were assessed for criteria of fibrosis/cirrhosis including characterization of hepatic nodules. These nodules were in addition, assessed by ultrasonography (US). Nodules ≥ 1 cm were investigated and monitored to evaluate malignant transformation. Clinical and hepatic serological data were recorded.

Results

Forty-six patients, median age of 16.5 years (15.4–17.9 years) were enrolled. All patients underwent US examination and MRI was performed in 35/46 patients. On MRI, 60% had hepatomegaly and 37% had signs of fibrosis/cirrhosis. Seven patients had together 13 nodules ≥ 1 cm in diameter. Only 4/13 (17%) where seen on US. Nodules had variable MRI signal characteristics including hepatobiliary contrast enhancement and two nodules revealed portal venous phase ‘wash-out’ on the first examination. No further imaging signs of malignancy were revealed during the follow-up period of median 24.4 (7–42) months.

Conclusion

The majority of adolescents with Fontan circulation had imaging findings of fibrosis/cirrhosis of varying severity. US had low detection rate of hepatic nodules compared to MRI. The imaging work-up before transition to adult cardiology care did not reveal findings suggestive of malignancy. However, the high prevalence of Fontan-associated liver disease calls for surveillance strategies even in childhood.

Supplementary Information

The online version of this article (10.1007/s00261-021-02994-0) contains supplementary material, which is available to authorized users.

Persisting and reoccurring cyanosis after Fontan operation is associated with increased late mortality

OBJECTIVES

The Fontan operation aims at reducing cyanosis and cardiac volume overload in patients with complex univentricular heart malformations. However, persisting or reoccurring cyanosis is frequently observed. We sought to systematically determine the prevalence and clinical consequences of persisting and secondary cyanosis after Fontan operation.

METHODS

A total of 331 Fontan patients, operated between 1984 and 2016 with a median postoperative follow-up of 7.9 (interquartile range 2.6-15.8) years, were studied retrospectively. Cyanosis was defined as transcutaneous oxygen saturation ≤93% at rest measured by pulse oximetry. Prevalence of cyanosis was analysed at 3 different time points (t1 = post-Fontan operation, t2 = post-Fontan cardiac catheterization, t3 = last follow-up) and the association of cyanosis with mortality was examined.

RESULTS

Prevalence of cyanosis was 50% at t1 and 39% at t3. Fenestration was patent in 71% and 33% of all cyanotic patients at t1 and t3, respectively. In patients with clinical indication for catheterization (t2; n = 178/331), prevalence of cyanosis was 72%. At t2, patent fenestration (33%), veno-venous collaterals (24%) or both (32%) were present. Thirty-six (11%) patients died during follow-up. In a time-varying multivariable Cox regression analysis, cyanosis was the strongest predictor for late mortality (P < 0.001, hazard ratio 12.2, 95% confidence interval 3.7-40.5).

CONCLUSIONS

Prevalence of cyanosis was considerable during long-term follow-up after Fontan operation and-as a surrogate parameter for unfavourable Fontan haemodynamics-is associated with increased late mortality. Accordingly, particular attention should be directed towards the persistence or reoccurrence of cyanosis during follow-up since it may indicate haemodynamic attrition and development of Fontan failure.

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.

Abdominal Imaging of Children and Young Adults With Fontan Circulation: Pathophysiology and Surveillance

OBJECTIVE. The Fontan procedure has significantly improved the survival in children with a functional single ventricle, but it is associated with chronically elevated systemic venous pressure that leads to multisystemic complications. Imaging plays an important role in assessing these complications and guiding management. The pathophysiology, imaging modalities, and current surveillance recommendations are discussed and illustrated. CONCLUSION. Significant improvement in survival of patients with Fontan circulation is associated with ongoing cardiac and extracardiac comorbidities and multisystemic complications. The liver and intestines are particularly vulnerable to damage. In addition, this patient population has been shown to be at increased risk of certain malignancies such as hepatocellular carcinoma and neuroendocrine tumors. Familiarity with imaging findings of Fontan-associated liver disease and other abdominal complications of the Fontan circulation is essential for radiologists because we are likely to encounter these patients in our general practice.

From congestive hepatopathy to hepatocellular carcinoma, how can we improve patient management?

Heart failure and liver disease often coexist because of systemic disorders and diseases that affect both organs as well as complex cardio-hepatic interactions. Heart failure can cause acute or chronic liver injury due to ischaemia and passive venous congestion, respectively. Congestive hepatopathy is frequently observed in patients with congenital heart disease and after the Fontan procedure, but also in older patients with chronic heart failure. As congestive hepatopathy can evolve into cirrhosis and hepatocellular carcinoma, screening for liver injury should be performed in patients with chronic cardiac diseases and after Fontan surgery. Fibrosis starts in the centro-lobular zone and will extend progressively to the portal area. Chronic liver injury can be reversible if heart function improves. However, in the case of terminal heart failure, uncontrolled by medical resources or by assistive device support, the combination of heart and liver transplants must be discussed in patients with chronic advanced liver fibrosis. In this review of the literature, we will focus on congestive hepatopathy and its complications, such as liver fibrosis and hepatocellular carcinoma, with the aim of improving the management and surveillance of patients experiencing these complications.