Increased hepatic stiffness as consequence of high hepatic afterload in the Fontan circulation: a vascular Doppler and elastography study

Biomechanics and clinical implications of Fontan upsizing

BACKGROUND

The Fontan operation, a palliative procedure for single ventricle patients, has evolved to improve outcomes and reduce complications. While extracardiac conduit (ECC) is favored for its simplicity and potential hemodynamic benefits, concerns arise about conduit size adequacy over time. Undersized ECC conduits may cause hemodynamic inefficiencies and long-term complications, while oversizing can lead to flow disturbances, stagnation, and thrombosis, necessitating surgical revision or upsizing to optimize hemodynamics.

OBJECTIVES

The study aimed to predict the impact of upsizing by developing a patient-specific workflow using cardiac magnetic resonance-based imaging and computational fluid dynamics to assess Fontan hemodynamic changes and determine the most optimal conduit size.

METHODS

We simulated upsizing in patient-specific models, computing reduction in power loss (PL), and analyzed pressure gradients, wall shear stress (WSS), and other local flow dynamic parameters such as vorticity and viscous dissipation that influence PL in a Fontan. Additionally, we quantified the impact of upsizing on hepatic flow distribution (HFD).

RESULTS

Across the patient cohort, upsizing resulted in a PL reduction of 16 %-63 %, with the greatest reduction observed in patients with the smallest pre-existing conduit sizes (14 mm). The optimal conduit size for minimizing PL was highly patient-specific. For instance, a 20 mm conduit reduced PL by 63 % in one patient, while another patient showed 16 % reduction with upsizing. Pressure gradients decreased by 15 %-35 %, correlating with the reduction in PL, while WSS decreased consistently with upsizing. Vorticity and viscous dissipation exhibited more variability but followed the overall trend of reduced PL. HFD changes were modest with a maximum variation of 30 %.

CONCLUSIONS

Our findings underscore the importance of individualized approaches in Fontan conduit upsizing. CFD-based quantitative evaluations of PL, pressure gradients, HFD, and WSS can guide optimal conduit sizing, improving long-term outcomes for patients.

Spleen shear wave elastography measurements do not correlate with histological grading of liver fibrosis in Fontan physiology: a preliminary investigation

BACKGROUND

Elevated spleen stiffness may be seen in patients with portal hypertension due to cirrhosis. In patients with Fontan physiology, elevated liver stiffness has been shown to correlate poorly with liver fibrosis. It is unknown whether spleen stiffness may instead serve as a surrogate marker of liver fibrosis in these patients.

OBJECTIVE

To compare spleen stiffness determined by shear wave elastography (SWE) with histological findings of an ultrasound-guided liver biopsy in patients who had undergone Fontan palliation as a potential surrogate for Fontan-associated liver disease.

MATERIALS AND METHODS

This was an IRB-approved single-center, retrospective study. Patients with Fontan palliation who had undergone both a spleen SWE study and a percutaneous liver biopsy between 2016 and 2020 were included. Biopsy, performed during cardiac catheterization, within 3 months of the SWE was required for inclusion. Using Kruskal-Wallis tests, spleen stiffness was compared with three liver biopsy scoring methods: Ishak, METAVIR, and congestive hepatic fibrosis score (CHFS). When available, Pearson's correlation was also used to compare collagen deposition determined using Sirius Red stain (%SR) with SWE values. A P-value < 0.05 was considered statistically significant.

RESULTS

Twenty-two patients (15 males) were included in the study, with a median age of 17 years (IQR is 14.8-20.5 years; age range: 7 years to 30.2 years). The median spleen stiffness was 2.94 m/s (IQR: 2.57-3.61 m/s; range: 1.48-4.27 m/s). The median Fontan pressure was 11 mm Hg (IQR: 10-13.3 mm Hg; range: 7-19 mm Hg) obtained within a median of 10 days (IQR: 1-41 days) of SWE. Splenic stiffness did not correlate with the extent of fibrosis determined by histology (all P > 0.05). There was also no statistically significant correlation between the %SR staining and SWE-determined spleen stiffness (Pearson's correlation of 0.165, P = 0.59, n = 13).

CONCLUSIONS

In this preliminary study, SWE spleen stiffness values did not correlate with biopsy-determined scoring of liver fibrosis in patients with Fontan physiology.

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.

Biomechanical Analysis of Age-Dependent Changes in Fontan Power Loss

The hemodynamics in Fontan patients with single ventricles rely on favorable flow and energetics, especially in the absence of a subpulmonary ventricle. Age-related changes in energetics for extracardiac and lateral tunnel Fontan procedures are not well understood. Vorticity (VOR) and viscous dissipation rate (VDR) are two descriptors that can provide insights into flow dynamics and dissipative areas in Fontan pathways, potentially contributing to power loss. This study examined power loss and its correlation with spatio-temporal flow descriptors (vorticity and VDR). Data from 414 Fontan patients were used to establish a relationship between the superior vena cava (SVC) to inferior vena cava (IVC) flow ratio and age. Computational flow modeling was conducted for both extracardiac conduits (ECC, n = 16) and lateral tunnels (LT, n = 25) at different caval inflow ratios of 2, 1, and 0.5 that corresponded with ages 3, 8, and 15+. In both cohorts, vorticity and VDR correlated well with PL, but ECC cohort exhibited a slightly stronger correlation for PL-VOR (>0.83) and PL-VDR (>0.89) than that for LT cohort (>0.76 and > 0.77, respectively) at all ages. Our data also suggested that absolute and indexed PL increase (p < 0.02) non-linearly as caval inflow changes with age and are highly patient-specific. Comparison of indexed power loss between our ECC and LT cohort showed that while ECC had a slightly higher median PL for all 3 caval inflow ratio examined (3.3, 8.3, 15.3) as opposed to (2.7, 7.6, 14.8), these differences were statistically non-significant. Lastly, there was a consistent rise in pressure gradient across the TCPC with age-related increase in IVC flows for both ECC and LT Fontan patient cohort. Our study provided hemodynamic insights into Fontan energetics and how they are impacted by age-dependent change in caval inflow. This workflow may help assess the long-term sustainability of the Fontan circulation and inform the design of more efficient Fontan conduits.

WFUMB Guideline/Guidance on Liver Multiparametric Ultrasound: Part 1. Update to 2018 Guidelines on Liver Ultrasound Elastography

The World Federation for Ultrasound in Medicine and Biology (WFUMB) endorsed the development of this document on multiparametric ultrasound. Part 1 is an update to the WFUMB Liver Elastography Guidelines Update released in 2018 and provides new evidence on the role of ultrasound elastography in chronic liver disease. The recommendations in this update were made and graded using the Oxford classification, including level of evidence (LoE), grade of recommendation (GoR) and proportion of agreement (Oxford Centre for Evidence-Based Medicine [OCEBM] 2009). The guidelines are clinically oriented, and the role of shear wave elastography in both fibrosis staging and prognostication in different etiologies of liver disease is discussed, highlighting advantages and limitations. A comprehensive section is devoted to the assessment of portal hypertension, with specific recommendations for the interpretation of liver and spleen stiffness measurements in this setting.

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.

Liver fibrosis detected by diffusion-weighted magnetic resonance imaging and its functional correlates in Fontan patients

OBJECTIVES

The evaluation of Fontan-associated liver disease is often challenging. Diffusion-weighted magnetic resonance imaging can detect hepatic fibrosis from capillary perfusion and diffusion abnormalities from extracellular matrix accumulation. This study investigated its role in the evaluation of liver disease in Fontan patients and explored possible diagnostic methods for early detection of advanced liver fibrosis.

METHODS

Stable adult Fontan patients who could safely be examined with magnetic resonance imaging were enrolled, and blood biomarkers, transient elastography were also examined.

RESULTS

Forty-six patients received diffusion-weighted imaging; and 58.7% were diagnosed with advanced liver fibrosis (severe liver fibrosis, 37.0%, and cirrhosis 21.7%). Two parameters of hepatic dysfunction, platelet counts (Spearman's ρ: -0.456, P = 0.001) and cholesterol levels (Spearman's ρ: -0.383, P = 0.009), decreased with increasing severity of fibrosis. Using transient elastography, a cut-off value of 14.2 kPa predicted the presence of advanced liver fibrosis, but with a low positive predictive value. When we included platelet count, cholesterol, post-Fontan years and transient elastography values as a composite, the capability of predicting advanced liver fibrosis was the most satisfactory (C statistic 0.817 ± 0.071, P < 0.001). A cut-off value of 5.0 revealed a sensitivity of 78% and a specificity of 82%.

CONCLUSIONS

In Fontan patients, diffusion-weighted imaging was helpful in detecting liver fibrosis that was correlated with hepatic dysfunction. A simple score was proposed for long-term surveillance and early detection of advanced liver disease in adult Fontan patients. For adult Fontan patients with a calculated score > 5.0, we may consider timely diffusion-weight imaging and early management for liver complications.

"Fontan Conduit Stent-Angioplasty and Progression of Fontan-Associated Liver Disease"

Patients with Fontan circulation insidiously develop congestive hepatopathy related to chronically reduced cardiac output and central venous hypertension, also known as Fontan-associated liver disease (FALD). Fontan pathway obstruction is increasingly detected and may accelerate FALD. The impact of conduit stent angioplasty on FALD is unknown. Retrospective, single-center review of patients with Fontan circulation who underwent conduit stent angioplasty at cardiac catheterization over 5-year period. Demographics and cardiac histories were reviewed. Labs, liver ultrasound elastography, echocardiogram, hemodynamic and angiographic data at catheterization were recorded pre- and post-stent angioplasty. Primary outcome was change in hepatic function via MELD-XI scores and liver stiffness (kPa), with secondary outcomes of ventricular function, BNP, and repeat catheterization hemodynamics. 33 patients underwent Fontan conduit stent angioplasty, 19.3 ± 7.0 years from Fontan operation. Original conduit diameter was 19.1 ± 1.9 mm. Prior to angioplasty, conduit size was reduced to a cross-sectional area 132 (91, 173) mm2 and increased to 314 (255, 363) mm2 post-stent. Subjects' baseline median MELD-XI of 11 (9, 12) increased to 12 (9, 13) at 19 ± 15.5 months post-angioplasty (n = 22, p = 0.053). There was no significant change in liver stiffness at 12.1 ± 8.9 months post-angioplasty (n = 15, p = 0.13). Median total bilirubin significantly increased (1.4 [0.9, 1.8]), from baseline 1.1 [0.7, 1.5], p = 0.04), as did median BNP (41 [0, 148] from baseline 34 [15, 79]; p = 0.02). There were no significant changes in ventricular function or repeat invasive hemodynamics (n = 8 subjects). Mid-term follow-up of Fontan subjects post-conduit stent angioplasty did not show improvements in non-invasive markers of FALD.

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.

Liver Fibrosis Scores Are Associated With Resting and Exercise Fontan and Pulmonary Artery Wedge Pressures: Insights Into FALD

BACKGROUND

Alterations in liver perfusion and venous hypertension have been implicated in the pathophysiology of Fontan-associated liver disease (FALD). However, the correlation between exercise hemodynamics and markers of FALD have not been studied.

METHODS

We performed a retrospective review of 32 consecutive adults undergoing exercise catheterisation at the Mayo Clinic, Minnesota. Invasive hemodynamics were correlated with aspartate transaminase to platelet ratio index (APRI) and the Fibrosis-4 (Fib-4) score, well validated surrogates of liver fibrosis.

RESULTS

The mean age was 30.9 ± 7 years. The mean APRI was 0.5 ± 0.2 and the mean Fib-4 score 1.3 ± 0.8. Fib-4 scores correlated with spleen size on abdominal imaging (r = 0.40; P = 0.03). Resting Fontan pressure was 13.9 ± 3.9 mm Hg and pulmonary artery wedge pressure (PAWP) 10.0 ± 3.5 mm Hg. At peak exercise (69.4 ± 23.2 W), Fontan pressures increased to 26.5 ± 6.2 mm Hg and PAWP to 22.4 ± 7.1 mm Hg. APRI and Fib-4 score were directly related to Fontan pressure and PAWP at rest and during exercise, and inversely related to exercise arterial O2 saturation. Fib-4 inversely correlated with O2 delivery indices. Similarly, when categorising patients according to high APRI (> 0.5 vs ≤ 0.5) or Fib-4 score (≥ 1.45 vs < 1.45) according to previously proposed cutoffs for diagnosis of liver fibrosis, those with elevated scores had higher resting and exercise Fontan and PAWP pressure with lower O2 arterial saturation.

CONCLUSIONS

APRI and Fib-4 score correlated with resting and exercise Fontan pressure and PAWP. In addition, Fib-4 scores were inversely related to O2 delivery indices. These findings support a role played by hepatic venous hypertension and reduced O2 supply in patients with FALD.

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.

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.

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.

Liver cirrhosis in children - the role of imaging in the diagnostic pathway

Liver cirrhosis in children is a rare disease with multifactorial causes that are distinct from those in adults. Underlying reasons include cholestatic, viral, autoimmune, hereditary, metabolic and cardiac disorders. Early detection of fibrosis is important as clinical stabilization or even reversal of fibrosis can be achieved in some disorders with adequate treatment. This article focuses on the longitudinal evaluation of children with chronic liver disease with noninvasive imaging tools, which play an important role in detecting cirrhosis, defining underlying causes, grading fibrosis and monitoring patients during follow-up. Ultrasound is the primary imaging modality and it is used in a multiparametric fashion. Magnetic resonance imaging and computed tomography are usually applied second line for refined tissue characterization, clarification of nodular lesions and full delineation of abdominal vessels, including portosystemic communications.

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.

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.

Noninvasive surrogates are poor predictors of liver fibrosis in patients with Fontan circulation

OBJECTIVES

Patients with Fontan circulation exhibit a high incidence of liver fibrosis and cirrhosis. Transient elastography (TE) and the enhanced liver fibrosis (ELF) test have proven useful as noninvasive surrogate markers of liver fibrosis for other chronic liver diseases. We evaluated whether TE and the ELF score can predict the degree of liver fibrosis in patients with Fontan circulation.

METHODS

We retrospectively reviewed the medical records of 45 adult patients with at least 10 years of Fontan duration who had undergone liver biopsy and investigated the relation between the fibrosis stage and TE and the ELF test results. Additionally, the association of these variables and other biochemical and hemodynamic parameters was assessed.

RESULTS

The mean age was 25.9 years and the mean Fontan duration was 20.8 years. Advanced liver fibrosis was present in 36 (80.0%) patients. TE or ELF score are comparable for patients with and without advanced liver fibrosis (mean 23.3 vs 24.8 kPa [P = .85] for TE; mean 8.94 vs 9.25 [P = .44] for the ELF score). However, N-terminal pro-brain natriuretic peptide level and ventricular end-diastolic pressure were higher in patients with advanced liver fibrosis (mean 224 vs 80 pg/mL [P < .01]; and mean 12 vs 9 mm Hg [P = .04], respectively). No independent predictor of advanced liver fibrosis was found in multivariate analysis.

CONCLUSIONS

TE and the ELF score were unable to predict the degree of liver fibrosis in Fontan patients. Liver biopsy remains as the only valid method to assess fibrotic burden in this population.

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

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

Comparison of Two Kinds of Two-Dimensional Shear Wave Elastography Techniques in the Evaluation of Jaundiced Infants Suspected of Biliary Atresia

Purpose: To compare the reliability and performance of Supersonic shear wave elastography (S-SWE) and Toshiba shear wave elastography (T-SWE) in the diagnosis of biliary atresia (BA) and assessment of liver fibrosis among jaundiced infants suspected of BA. Material and Methods: A total of 35 patients with suspected BA who underwent both S-SWE and T-SWE examinations were prospectively included. Diagnostic performances of S-SWE and T-SWE in identifying BA were evaluated. The correlation between two types of SWE values and histological liver fibrosis stages by Metavir scores were investigated in 21 patients with pathology results. The intraclass correlation coefficients (ICCs) were calculated in 16 patients for inter- and intra-observer agreement. The area under the receiver operating characteristic curve (AUC) analysis was compared using a DeLong test. Results: There were 22 patients with BA and 13 patients without BA. The diagnostic performance of S-SWE was comparable to that of T-SWE (AUC 0.895 vs. 0.822, p = 0.071) in diagnosing BA. The AUCs of S-SWE in predicting liver fibrosis stages were from 0.676 to 1.000 and showed no statistical differences from that of T-SWE (from 0.704 to 1.000, all p > 0.05). T-SWE provided higher inter-operator agreement (ICC 0.990) and intra-operator agreement (ICCs 0.966−0.993), compared with that of S-SWE in a previous study (ICC 0.980 for inter-operator and 0.930−0.960 for intra-operator). Conclusions: For infants suspected of BA, T-SWE had good performances in the diagnosis of BA and the assessment of liver fibrosis compared with S-SWE. Furthermore, T-SWE showed higher measurement reproducibility than S-SWE.

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.

Interplay between right atrial function and liver stiffness in adults with repaired right ventricular outflow obstructive lesions

AIMS

This study determined the associations between right atrial (RA) and right ventricular (RV) mechanics and liver stiffness in adults with repaired tetralogy of Fallot (TOF), pulmonary atresia with intact ventricular septum (PAVIS), and pulmonary stenosis (PS).

METHODS AND RESULTS

Ninety subjects including 26 repaired TOF, 24 PAIVS, and 20 PS patients and 20 controls were studied. Hepatic shear wave velocity and tissue elasticity (E), measures of liver stiffness, were assessed by two-dimensional shear wave elastography, while RA and RV mechanics were assessed by speckle tracking echocardiography. Deformation analyses revealed worse RV systolic strain and strain rate, and RA peak positive and total strain, and strain rates at ventricular systole and at early diastole in all of the patient groups compared with controls (all P < 0.05). Compared with controls, all of the patient groups had significantly greater shear wave velocity and hepatic E-value (all P < 0.05). Shear wave velocity and hepatic E-value correlated negatively with RV systolic strain rate, and RA positive strain, total strain, and strain rate at ventricular systole and at early diastole (all P < 0.05). Multivariate analyses revealed RA strain rate at early diastole (P = 0.015, P < 0.001), maximum RA size (P < 0.001, P < 0.001), and severity of pulmonary regurgitation (P = 0.05, Pp = 0.014) as significant correlates of shear wave velocity and hepatic E-value.

CONCLUSION

In adults with repaired TOF, PAIVS, and PS, RA dysfunction and pulmonary regurgitation are associated with liver stiffness.

MR imaging features and long-term evolution of benign focal liver lesions in Budd-Chiari syndrome and Fontan-associated liver disease

PURPOSE

To compare the magnetic resonance imaging (MRI) features of benign liver lesions developed on Budd-Chiari syndrome (BCS) with those on Fontan-associated liver disease (FALD) and to describe their long-term progression.

MATERIALS AND METHODS

Patients with BCS or FALD who underwent MRI between 2010 and 2020 were retrospectively included. MRI features of nodules (≥ 5 mm) at baseline and at final follow-up were reviewed. The final diagnosis of benign lesion was based on a combination of clinical and biological data and findings at follow-up MRI examination.

RESULTS

Two-hundred and thirty benign liver lesions in 39 patients with BCS (10 men, 29 women; mean age, 36 ± 11 [SD] years; age range: 15-66 years) and 84 benign lesions in 14 patients with FALD (2 men, 12 women; mean age, 31 ± 10 [SD] years; age range: 20-48 years) were evaluated. On baseline MRI, BCS nodules were more frequently hyperintense on T1-weighted (183/230, 80%) and hypointense on T2-weighted (142/230; 62%) images, while FALD nodules were usually isointense on both T1- (70/84; 83%) and T2-weighted (64/84; 76%) images (all P< 0.01). Most lesions showed arterial phase hyperenhancement (222/230 [97%] vs. 80/84 [95%] in BCS and FALD, respectively; P = 0.28) but wash-out was more common in BCS (64/230 [28%] vs. 9/84 [11%]; P < 0.01). At follow-up, changes were more frequent in BCS nodules with more frequent disappearance (P < 0.01), changes in size, signal intensity on T2-weighted, portal, and delayed phase, and in the depiction of washout and capsule (all P ≤ 0.03).

CONCLUSION

MRI features of benign lesions are different at diagnosis and during the course of the disease between BCS and FALD. Changes in size and MRI features are more frequent in benign lesions developed in BCS.

The effect of water intake on ultrasound tissue characteristics and hemodynamics of adult livers

Aim of the study

To assess the effect of water intake on ultrasound tissue characteristics and hemodynamics of adult livers.

Material and methods

In February 2020, we prospectively performed ultrasound shear wave elastography and attenuation imaging (ATI) of the liver parenchyma, and spectral Doppler sonography of the portal vein and hepatic artery in 19 adult healthy volunteers (10 men and 9 women, mean age 27 years, mean body mass index 24.65 kg/m²). We measured liver shear wave velocity (SWV, m/s), shear wave dispersion (SWD, m/s/kHz), attenuation coefficient (dB/cm/MHz), main portal vein velocity (PVV, cm/s), hepatic artery peak systolic velocity (PSV, cm/s), and end diastolic velocity (EDV, cm/s) immediately before and at different time points (15, 30, 45, and 60 minutes) after water intake (1.0 l water and 1.5 l water for body weight < 150 lbs. and ≥ 150 lbs., respectively).

Results

The differences in SWV, PVV, hepatic artery PSV and EDV before and after water intake were significant (p < 0.01) whereas the differences in SWD and ATI were not (p > 0.05) based on repeated measures ANOVA tests. The values of SWV, PVV, PSV, and EDV reached a peak at 30-45 minutes and returned to baseline 60 minutes after water intake. We observed positive correlations of SWV with PVV, PSV, and EDV in linear regression analyses (r² > 0.73).

Conclusions

Water intake affects the liver stiffness and hemodynamics. No water intake at least one hour prior to liver ultrasound elastography and Doppler sonography is recommended.

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.

Congenital heart disease-associated liver disease: a narrative review

Congenital heart diseases (CHD) can be associated with liver dysfunction. The cause for liver impairment can result out of a wide spectrum of different causes, including liver congestion, hypoxemia or low cardiac output. Fortunately, most CHD show a good long-term outcome from a cardiac perspective, but great attention should be paid on non-cardiac health problems that develop frequently in patients suffering from CHD. The treatment of liver dysfunction in CHD requires a close multidisciplinary management in a vulnerable patient collective. Unfortunately, structured recommendations on the management of liver dysfunction in patients with CHD are scarce. The objective of this review is to provide insights on the pathophysiology and etiologies of liver dysfunction as one of the most relevant non-cardiac problems related to CHD. Furthermore, we advise here on the management of liver disease in CHD with special attention on assessment of liver dysfunction, management of portal hypertension as well as on surveillance and management of hepatocellular carcinoma (HCC). A multidisciplinary perspective may help to optimize morbidity and mortality in the long-term course in these patients. However, as evidence is low in many aspects, we encourage the scientific community to perform prospective studies to gain more insights in the treatment of liver dysfunction in patients with CHD.

Efficacy of shear wave elastography for assessment of liver function in patients with heart failure

AIMS

Liver dysfunction is important for prognosis in heart failure (HF). Shear wave elastography (SWE), which is a novel ultrasound technique for charactering tissues, has been used in liver diseases. However, clinical implication of SWE, including dispersion slope, remains unknown in heart diseases. This study aimed to evaluate the efficacy of SWE assessing liver function in the severity of HF.

METHODS AND RESULTS

We enrolled 316 consecutive patients with or suspected heart diseases, who were classified according to the American College of Cardiology Foundation/American Heart Association stage of HF, including 37 with Stage A, 139 with Stage B, 114 with Stage C, and 26 with Stage D, and 45 normal subjects. Elasticity and dispersion slope of shear wave were assessed according to the HF stage. Elasticity and dispersion slope were not elevated in normal subjects and patients with Stage A. Elasticity was slightly increased from Stage A to Stage C and was remarkably elevated in Stage D (normal: 5.2 ± 1.1 kPa, Stage A: 5.4 ± 1.2 kPa, Stage B: 6.4 ± 1.8 kPa, Stage C: 7.8 ± 3.5 kPa, and Stage D: 17.7 ± 12.7 kPa), whereas dispersion slope was gradually increased from Stage A to Stage D (normal: 9.7 ± 1.7m/s/kHz, Stage A: 10.4 ± 1.6m/s/kHz, Stage B: 11.7 ± 2.4m/s/kHz, Stage C: 13.2 ± 3.4m/s/kHz, and Stage D: 17.6 ± 5.6 m/s/kHz). In the early HF stage, dispersion slope was elevated. In the advanced HF stage, both elasticity and dispersion slope were elevated. Liver function test abnormalities were observed only from Stage C or Stage D.

CONCLUSIONS

Dispersion slope could detect early liver damage, and the combination of elasticity and dispersion slope could clarify the progression of liver dysfunction in HF. SWE may be valuable to manage therapeutic strategies in patients with HF.

Prognostic Value of Liver and Spleen Stiffness in Patients with Fontan Associated Liver Disease (FALD): A Case Series with Histopathologic Comparison

The Fontan operation is the current surgical procedure to treat single-ventricle congenital heart disease, by splitting the systemic and pulmonary circulations and thus permitting lifespan to adulthood for the majority of newborns. However, emerging data are showing that Fontan-associated liver disease (FALD) is an increasing related cause of morbidity and mortality in patients with the Fontan circuit. We described the clinical, laboratory, and transient elastography (TE) findings in a case series of adults with the Fontan circuit, and also correlated data with post-mortem histological features, aimed to define the prognostic value of TE in the staging of FALD. All patients presented signs of a long-standing Fontan failure, characterized by reoperation need, systemic ventricle dysfunction, and FALD stigmata (liver and spleen enlargement, portal vein and inferior vena cava dilation, and abnormal liver function tests). Liver and spleen stiffness (LS and SS) values were indicative of significant liver fibrosis/cirrhosis and the presence of suggestive portal hypertension (LS mean 35.9; range 27.3–44.7 kPa; SS mean 42.1, range 32.2–54.5 kPa). Post-mortem evaluations confirmed a gross hepatic architecture distortion in all cases. All patients died from severe complications related to liver dysfunction and bleeding. TE correlated well with pathological findings and FALD severity. We propose this validated and harmless technique to monitor liver fibrosis extension and portal hypertension over time in Fontan patients, and to identify the optimal timing for surgical reoperations or orthotopic-heart transplantation (OHT), avoiding a higher risk of morbidity and mortality in cases with severe FALD.

Calibration of an Electrical Analog Model of Liver Hemodynamics in Fontan Patients

Fontan associated liver disease is a common complication in patients with Fontan circulation, who were born with a single functioning heart ventricle. The hepatic venous pressure gradient (HVPG) is used to assess liver health and is a surrogate measure of the pressure gradient across the entire liver (portal pressure gradient (PPG)). However, it is thought to be inaccurate in Fontan patients. The main objectives of this study were (1) to apply an existing detailed lumped parameter model (LPM) of the liver to Fontan patients using patient-specific clinical data and (2) to determine whether HVPG is a suitable measurement of PPGs in these patients. An existing LPM of the liver blood circulation was applied and tuned to simulate patient-specific liver hemodynamics. Geometries were collected from seven adult Fontan patients and used to evaluate model parameters. The model was solved and tuned using waveform measurements of flows, inlet and outlet pressures. The predicted ratio of portal to hepatic venous pressures is comparable to in vivo measurements. The results confirmed that HVPG is not suitable for Fontan patients, as it would underestimate the portal pressures gradient by a factor of 3 to 4. Our patient-specific liver model provides an estimate of the pressure drop across the liver, which differs from the clinically used metric HVPG. This work represents a first step toward models suitable to assess liver health in Fontan patients and improve its long-term management.

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.

Noninvasive ultrasound technique for assessment of liver fibrosis and cardiac function in Fontan-associated liver disease: diagnosis based on elastography and hepatic vein waveform type

PURPOSE

Patients with a Fontan circulation tend to develop liver fibrosis, liver cirrhosis and even hepatocellular carcinoma. A noninvasive ultrasound technique for liver fibrosis and cardiac function assessment in Fontan-associated liver disease (FALD) is needed to evaluate disease progression in real time. This study aimed to evaluate whether hepatic vein (HV) waveform analysis and elastography could be alternative markers to cardiac index (CI) in patients with FALD and assess factors influencing elastography measurements in FALD cases.

METHODS

All patients underwent cardiac catheterization, B-mode ultrasound and ultrasound elastography measurement. Moreover, we measured serum markers related to fibrosis and examined HV blood flow using duplex Doppler ultrasonography.

RESULTS

Forty-three patients (median age, 17 years; interquartile range, 12-25 years; 29 men, 6 with liver biopsy) were enrolled. The real-time tissue elastography (RTE) value was significantly higher in patients who underwent surgery > 7 years prior, suggesting that this value probably reflects the liver fibrosis due to FALD from the early fibrosis stage. The ultrasound elastography did not significantly correlate with hemodynamic parameters. The area under the receiver operating curve for the diagnosis of CI < 2.2 L/min/m² using HV waveform was superior to the results from elastography and calculated fibrosis indices.

CONCLUSION

HV waveform can be used as a noninvasive measurable surrogate marker for CI. The RTE value increased overtime after the operation and would reflect liver fibrosis. The combination of RTE and HV waveform type could be useful noninvasive tools to evaluate clinical conditions in FALD patients in real time.

Surveillance of Fontan-associated liver disease: current standards and a proposal from the European Society of Paediatric Radiology Abdominal Task Force

Since Francis Fontan first introduced the eponymous technique, the Fontan procedure, this type of surgical palliation has allowed thousands of children affected by specific heart malformations to reach adulthood. Nevertheless, abdominal, thoracic, lymphatic and neurologic complications are the price that is paid by these patients. Our review focuses on Fontan-associated liver disease; the purpose is to summarize the current understanding of its physiopathology, the aim of follow-up and the specific radiologic follow-up performed in Europe. Finally, we as members of the Abdominal Task Force of the European Society of Paediatric Radiology propose a consensus-based imaging follow-up algorithm.

Quantification of Hepatic and Splenic Stiffness After Fontan Procedure in Children and Clinical Implications

We aimed to investigate Fontan associated liver disease in children by shear wave elastography (SWE). This is a single-center, prospective case-control study included 41 patients with Fontan physiology and 30 healthy controls. Hepatic and splenic shear wave elasticity values were exhibited both as kPa and m/s. The mean hepatic SWE values of Fontan patients (n = 41; 15.8 ± 3.2 kPa or 2.5 ± 1.8 m/s) were significantly higher than the control group (n = 30; 5.59 ± 0.6 kPa or 1.37 ± 0.07 m/s) (P < 0.001). The mean splenic SWE values of Fontan patients were (25.6 ± 4.61 kPa or 2.85 ± 0.22 m/s) significantly higher than the control group (15.9 ± 1.44 kPa or 2.29 ± 0.1 m/s) (P < 0.001). There were statistically significant positive correlations among the follow-up duration after the Fontan procedure with NT-proBNP (P = 0.008, r = 1) and prothrombin time (P = 0.009, r = 0.4) as well as the hepatic SWE values with alanine aminotransferase (P = 0.039, r = 0.32), gamma-glutamyl transferase (P = 0.045, r = 0.31), and PT (P = 0.011, r = 0.39). There has been statistically significant moderate positive correlations of splenic stiffness values with PT (P = 0.047, r = 0.34), and INR (P = 0.038, r = 0.35). The sensitivity and specificity of liver stiffness cutoff value as 11.1 kPa for detection of Fontan associated liver disease were 95% and 100%, respectively. The hepatic and splenic stiffness increase independently in Fontan patients due to parenchymal disease. Hepatic SWE is a reliable and noninvasive predictor of early hepatic alterations that could not be detected only by biochemical results or routine ultrasound examinations.

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.

A window into portal hemodynamics in adult fontan patients?

BACKGROUND

Fontan circulation alters portal venous hemodynamics, causing chronic passive hepatic congestion and fibrosis. This congestion increases liver stiffness (LS) leading to overestimates of liver fibrosis as measured by ultrasound shear wave elastography (SWE) of the liver. We evaluated whether Fontan circulation has a similar effect on spleen stiffness (SS) and SS/LS ratio as measured by SWE.

METHODS

We retrospectively compared the SS of adult Fontan patients to age and gender matched, control patients without congenital heart disease. We correlated SS measurements to LS measurements and also performed a limited subgroup analysis of SS in Fontan patients with various manifestations of Fontan Associated Liver Disease.

RESULTS

SS in Fontan patients was similar to healthy controls (1.43 vs. 1.36 m/s, p = 0.26). LS was elevated in 78% of the Fontan patients (mean 1.68 m/s, SD 0.31, 95% CI 1.53-1.85). The correlation between LS and SS was modest (Pearson's correlation coefficient, r = 0.5) but did not reach statistical significance (p = 0.06). The mean SS/LS ratio was 0.85 (95% CI 0.77-0.94).

CONCLUSION

Based on our study cohort, SS in Fontan patients is similar to age and gender matched control patients without congenital heart disease. The SS/LS ratio, however, is frequently less than 1, which is lower than that reported in both healthy patients and those with other forms of non-cardiac liver disease. SS and SS/LS ratio may be a useful indicator of portal hemodynamics in Fontan patients.

Noninvasive Assessment of Liver Stiffness in Patients Undergoing the Fontan Procedure

BACKGROUND

Hepatic derangements and liver injury following the Fontan operation (FO) may progress in some cases to hepatic fibrosis (HF) and cirrhosis. The respective roles of transient elastography (TE) or FibroScan, shear wave elastography (SWE), and aspartate transaminase to platelet ratio index (APRI) in assessing liver stiffness (LS) and possible liver injury in these patients are unclear.

METHODS

Thirty-nine patients (31 males), mean age 11.8 ± 5.7 years, median 11 years (interquartile range: 7-14.7 years), undergoing the FO between November 2017 and December 2018 were included. Liver stiffness and HF assessment was done with TE, SWE, and APRI in the preoperative period and postoperatively at 3-, 6-, and 12-month interval.

RESULTS

The LS values increased over time (postoperative values at 3, 6, and 12 months) as compared to preoperative values by both FibroScan and SWE. The change in liver stiffness measurement (LSM) was statistically significant: LSM0 to LSM3 (P ≤ .0001), LSM0 to LSM6 (P ≤ .0001), and LSM0 to LSM12 (P = .001). Similarly, significant changes were observed on SWE: SWE0 to SWE3 (P ≤ .0001), SWE0 to SWE6 (P ≤ .0001), and SWE0 to SWE12 (P = .001). There was no significant change in the APRI values over time.

CONCLUSION

Noninvasive methods such as FibroScan and SWE may be of use to assess LS in follow-up of patients undergoing the FO for early recognition of hepatic changes.

Early development of hepatic fibrosis after Fontan procedure: A non-invasive study of a subclinical liver disease

BACKGROUND

To evaluate subclinical liver fibrosis after Fontan procedure using a comprehensive method that reflects the overall liver status rather than the focal biopsy lesion.

METHOD

This cross-sectional study included 66 patients without symptoms of liver disease who had at least 5 years of elapsed time since the Fontan procedure (time since Fontan procedure 17.5 ± 7.3 years). Serum enhanced liver fibrosis (ELF) scores and 2D shear wave elastography (SWE), which are expected to detect liver fibrosis earlier than liver enzyme tests and ultrasonography, were evaluated along with general examinations.

RESULTS

Liver cirrhosis diagnosed by ultrasonography showed a marked increase 16 years after surgery (elapsed time: 6-15 years since Fontan, 43.8%; 16-25 years, 70.8%; 26-35 years, 90.0%). The age-adjusted ELF score and liver stiffness according to SWE were elevated during the early postoperative period (6-15 years since Fontan). In adulthood (elapsed time > 16 years), the adjusted ELF score was correlated with liver stiffness (r = 0.514, p = .009) and liver enzyme levels. There was no correlation between liver fibrosis and the Fontan palliation type. AST to platelet count ratio and FIB-4, which are non-invasive fibrosis markers, presumed absence of fibrosis in approximately 90% of patients.

CONCLUSIONS

In the evaluation of early liver fibrosis after the Fontan procedure, abnormal findings of 2D SWE and ELF scores were observed before abnormal ultrasound and liver enzyme results. Therefore, these indicators may be helpful for the diagnosis of early liver fibrosis, and further longitudinal study might be needed.

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.

Hepatic and splenic sonographic and sonoelastographic findings in pulmonary arterial hypertension

Purpose

The aim of this study was to evaluate the associations of sonographic and sonoelastographic parameters with clinical cardiac parameters, as well as to assess their value in predicting survival in patients with pulmonary arterial hypertension (PAH).

Methods

Thirty-six patients with PAH and normal liver function were prospectively enrolled in this prospective study along with 26 healthy controls, all of whom underwent ultrasound and point shear wave elastography examinations. Additionally, the portal vein pulsatility index (PVPI), inferior vena cava collapsibility index, and clinical cardiac variables were obtained in PAH patients. The values of hepatic (LV_s) and splenic shear wave velocity (SV_s) were compared between PAH patients and controls. The relationships between all sonographic and clinical parameters in the PAH patients were analyzed. Furthermore, their prognostic value in predicting survival was investigated.

Results

LV_s values in PAH patients (median, 1.62 m/s) were significantly higher than in controls (median, 0.99 m/s), while no significant difference was observed in SV_s values. Patients with higher grades of tricuspid regurgitation (TR) had significantly different values of PVPI (P=0.010) and sonoelastographic parameters (P<0.001 for LV_s and P=0.004 for SV_s) compared to those with less severe TR. Tricuspid annular plane systolic excursion values were the only investigated parameter found to be associated with survival (hazard ratio, 0.814; 95% confidence interval, 0.694 to 0.954; P=0.011).

Conclusion

Our results demonstrated a direct association between cardiac congestion (i.e., the severity of TR) and liver stiffness, which should be kept in mind during the assessment of fibrosis in patients with PAH.

Ultrasound liver elastography beyond liver fibrosis assessment

Several guidelines have indicated that liver stiffness (LS) assessed by means of shear wave elastography (SWE) can safely replace liver biopsy in several clinical scenarios, particularly in patients with chronic viral hepatitis. However, an increase of LS may be due to some other clinical conditions not related to fibrosis, such as liver inflammation, acute hepatitis, obstructive cholestasis, liver congestion, infiltrative liver diseases. This review analyzes the role that SWE can play in cases of liver congestion due to right-sided heart failure, congenital heart diseases or valvular diseases. In patients with heart failure LS seems directly influenced by central venous pressure and can be used as a prognostic marker to predict cardiac events. The potential role of LS in evaluating liver disease beyond the stage of liver fibrosis has been investigated also in the hepatic sinusoidal obstruction syndrome (SOS) and in the Budd-Chiari syndrome. In the hepatic SOS, an increase of LS is observed some days before the clinical manifestations; therefore, it could allow an early diagnosis to timely start an effective treatment. Moreover, it has been reported that patients that were successfully treated showed a LS decrease, that reached pre-transplantation value within two to four weeks. It has been reported that, in patients with Budd-Chiari syndrome, LS values can be used to monitor short and long-term outcome after angioplasty.

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.

Fontan protein-losing enteropathy is associated with advanced liver disease and a proinflammatory intestinal and systemic state

BACKGROUND AND AIMS

Protein-losing enteropathy (PLE) after Fontan surgery carries significant morbimortality. Its pathophysiology and association with other Fontan complications are poorly understood. Our aims were to examine whether Fontan-PLE is associated with greater liver damage and to assess the presence of systemic and intestinal inflammation.

METHODS

Fontan patients with PLE and Fontan controls without PLE matched for age and Fontan surgery procedure were included. Data were prospectively compiled on blood and stool tests, liver imaging, elastography, cardiac-MRI and cardiac catheterization.

RESULTS

Twenty-nine Fontan patients were enrolled (14 with PLE and 15 controls without PLE). Patients with PLE had more advanced liver disease estimated by non-invasive methods: blunt liver margins on ultrasonography (71.4% vs 26.7%, P = .027), greater median liver stiffness (25.4 vs 14.5 kPa, P = .003) and higher FIB-4 (P = .016). Portal hypertension-related signs were more common in patients with PLE including ascites (P = .035), larger spleen size (P = .005), oesophageal varices/splanchnic collateral shunts (P = .03), higher liver stiffness-spleen size-to-platelet ratio risk score (P < .001) and lower platelet count (P = .01). Systemic proinflammatory cytokines (TNF-α, interleukin-6), biomarkers of intestinal permeability (intestinal fatty-acid binding protein) and faecal calprotectin concentrations were also significantly increased in Fontan-PLE (P < .05). Faecal calprotectin directly correlated with alpha-1 antitrypsin clearance and inversely with cardiac index, total serum proteins and body mass index.

CONCLUSION

Fontan-PLE is associated with advanced liver disease and increased markers of systemic inflammation and intestinal permeability. Faecal calprotectin is elevated and correlates with Fontan-PLE severity. Liver assessment is mandatory in all Fontan patients, and especially in those with PLE.

Liver Strain Using Feature Tracking of Cine Cardiac Magnetic Resonance Imaging: Assessment of Liver Dysfunction in Patients with Fontan Circulation and Tetralogy of Fallot

We propose a novel method to quantify pulsatile liver deformation using the feature tracking method of cardiac cine magnetic resonance imaging (MRI) and investigate its association with liver dysfunction in long-term postoperative patients after Fontan and intracardiac repair for the tetralogy of Fallot (TOF). Standard cine MRI which was previously performed for cardiac evaluation of 85 patients who underwent Fontan operation (mean age, 22.9 years), 43 patients with TOF (mean age, 34.6 years), and 32 healthy controls (mean age, 42.3 years) were retrospectively analyzed. Pulsatile liver deformation in the craniocaudal direction was calculated using the feature tracking method of cardiac cine imaging derived from cine-balanced turbo field-echo sequences performed on a 1.5 Tesla MR scanner, and was defined as liver strain. The liver strain was compared across the three patient groups using one-way analysis of variance. Liver dysfunction by a liver strain were compared using the Mann-Whitney U test. Liver strain for patients who underwent Fontan operation and TOF patients was significantly lower than controls (Fontan, 13.3 ± 6.5%; TOF, 15.0 ± 11.2%; controls, 23.1 ± 10.2%, p < 0.0001). In Fontan and TOF patients, MELD score was significantly greater for patients with a liver strain < 15% than those with values > 15% (5.9 ± 5.8 vs. 2.9 ± 2.9, p < 0.001). Lower liver strain values were found in adolescent and adult patients after Fontan operation and TOF, and correlates with the severity of liver injury, expressed as MELD score. Our method can evaluate hepatic function in adult congenital heart disease, together with the assessment of cardiac function.

Fontan-Associated Liver Disease: Spectrum of Disease in Children and Adolescents

Background Information is evolving on liver disease in pediatric patients with Fontan physiology. The purpose of this investigation is to evaluate the spectrum of liver disease in a pediatric population of patients with Fontan physiology and evaluate transient elastography (TE) as a noninvasive marker of liver disease. Methods and Results We prospectively enrolled all children with Fontan physiology. All patients underwent comprehensive liver evaluation including liver enzymes (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, alkaline phosphatase), aspartate transaminase to platelet ratio index, albumin, bilirubin, international normalized ratio, complete blood cell count, abdominal ultrasound, and TE. Transjugular liver biopsies and hemodynamic measurements were performed in a subset of patients. A total of 76 children (median, 11.7; interquartile range, 8.4-14.8 [56% male]) were evaluated, with 17 having a transjugular liver biopsy (median 14.8 years; interquartile range, 14.3-17.4). All biopsies showed pathological changes. The severity of liver pathology did not correlate with TE. There was a positive correlation between TE and time since Fontan (R=0.42, P<0.01), aspartate transaminase to platelet ratio index (R=0.29, P=0.02), aspartate transaminase (R=-0.42, P<0.01), and platelets (R=-0.42, P<0.01). Splenomegaly on abdominal ultrasound was correlated with TE (z=-2.2, P=0.03), low platelet count (z=1.9, P=0.05), low aspartate transaminase (z=1.9, P=0.02), and low alkaline phosphatase (z=2.4, P=0.02). Conclusions Liver disease was ubiquitous in our cohort of pediatric patients with Fontan Physiology. Given the correlation between TE and time from Fontan, TE shows potential as a prospective marker of liver pathology. However, individual measurements with TE do not correlate with the severity of pathology. Given the prevalence of liver disease in this population, protective measures of liver health as well as routine liver health surveillance should be implemented with consideration for hepatology consultation and biopsy in the event of abnormal liver biochemical markers or imaging.