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

Accuracy of elastography versus biopsy in assessing severity of liver fibrosis in young Fontan patients

OBJECTIVES

We performed a single-centre retrospective study comparing the accuracy of non-invasive elastography with liver biopsy in accurate assessment of Fontan-associated liver disease.

METHODS

Fontan patients who underwent combined assessment with a percutaneous liver biopsy and non-invasive elastography between January 2015 and December 2023 at our Children's hospital were included. Liver biopsies were classified using the Congestive Hepatic Fibrosis Score as early Fontan-associated liver disease (scores 1, 2) and advanced Fontan-associated liver disease (score 3/bridging fibrosis and score 4/cirrhosis). Elastography values were categorised as advanced Fontan-associated liver disease for liver elasticity >2.1 m/s by ultrasound and liver stiffness >5 KPa on magnetic resonance elastography.

RESULTS

We included 130 patients (116 children, 89%, mean age at biopsy: 14.6 years ± 3.6) who underwent liver biopsy at a mean duration of 11.1 years (±0.3) following Fontan surgery. Advanced Fontan-associated liver disease was noted in 41 (31.5%) patients with 13 (10%) showing frank cirrhosis. Pre-biopsy ultrasound showed advanced liver fibrosis in 18/125 (14%), with low sensitivity (23%), high specificity (90%), and low accuracy (68%, k = 0.1) in diagnosing advanced Fontan-associated liver disease. Similarly, pre-biopsy magnetic resonance elastography showed advanced fibrosis in 23/86 (27%) of patients, with low sensitivity (30%), fair specificity (75%), and low accuracy (63%, k = 0.1). Interestingly, advanced Fontan-associated liver disease was missed by ultrasound in 29% and by magnetic resonance elastography in 25% of patients. Advanced Fontan-associated liver disease was associated with lower platelet count (p = 0.02) and higher Gamma-glutamyl Transferase levels (p = 0.02).

CONCLUSION

Advanced hepatic fibrosis is common among paediatric Fontan patients. Non-invasive elastography may overestimate and underestimate the degree of liver fibrosis, and therefore, liver biopsy may be required for confirming disease severity.

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.

Cardiovascular remodelling in response to exercise training in patients after the Fontan procedure: a pilot study

BACKGROUND

The cardiovascular adaptations associated with structured exercise training in Fontan patients remain unknown. We hypothesised that short-term training causes cardiac remodelling and parallel improvement in maximal exercise capacity (VO2 max) in these patients.

METHODS AND RESULTS

Five patients, median age 19.5 (17.6-21.3) years, with a history of Fontan operation meeting inclusion/exclusion criteria, participated in a 3-month training programme designed to improve endurance. Magnetic resonance images for assessment of cardiac function, fibrosis, cardiac output, and liver elastography to assess stiffness were obtained at baseline and after training. Maximal exercise capacity (VO2 max) and cardiac output Qc (effective pulmonary blood flow) at rest and during exercise were measured (C2H2 rebreathing) at the same interval. VO2 max increased from median (IQR) 27.2 (26-28.7) to 29.6 (28.5-32.2) ml/min/kg (p = 0.04). There was an improvement in cardiac output (Qc) during maximal exercise testing from median (IQR) 10.3 (10.1-12.3) to 12.3 (10.9-14.9) l/min, but this change was variable (p = 0.14). Improvement in VO2 max correlated with an increase in ventricular mass (r = 0.95, p = 0.01), and improvement in Quality-of-life inventory (PedsQL) Cardiac scale scores for patient-reported symptoms (r = 0.90, p = 0.03) and cognitive problems (r = 0.89, p = 0.04). The correlation between VO2 max and Qc showed a positive trend but was not significant (r = 0.8, p = 0.08). No adverse cardiac or liver adaptations were noted.

CONCLUSION

Short-term training improved exercise capacity in this Fontan pilot without any adverse cardiac or liver adaptations. These results warrant further study in a larger population and over a longer duration of time.

TRIAL REGISTRATION NUMBER

NCT03263312, Unique Protocol ID: STU 122016-037; Registration Date: 18 January, 2017.

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.

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.

Liver stiffness in Fontan patients: the effect of respiration and food intake

Objectives

For several years, patients with single ventricle hearts have been palliated according to the Fontan principle. One well known long-term consequence in these patients is the Fontan-associated liver disease and fibrosis, which occurs due to the chronically increased Central Venous Pressure (CVP) after Fontan palliation. It carries an increased risk of liver cirrhosis and hepatocellular carcinoma over time. Liver elastography (LE) is a non-invasive, safe, and feasible ultrasound method to determine liver stiffness and the stage of liver fibrosis. Usually, this examination must be performed in a sober condition and strict inspiratory hold to optimize the results and may therefore be difficult to perform on children as a routine examination. However, the influence of food intake and respiration on these results in Fontan patients is unclear. To optimize the implementation for this examination especially in children, the effects of food intake and breathing maneuvers on liver stiffness in patients with Fontan circulation were investigated.

Methods

For this prospective study, 25 Fontan patients (group 1) and 50 healthy volunteers (group 2) were examined. The two groups were additionally divided into two age categories (group 1a: 10-19  years; group 1b: 20-29  years; group 2a: 15-19  years; group 2b: 20-25  years). Liver stiffness was measured by liver elastography once before food intake (=T0, with 6 h of fasting). Subsequently the participants consumed a standardized chocolate drink (500  mL) with nutritional distribution corresponding to a standardized meal (600  kcal). Liver stiffness was then determined 15, 30, 45, 60, 90, 120, 150, and 180  min after ingestion. Each measurement of liver stiffness was performed during maximal inspiratory and expiratory holds. The study was reviewed and approved by the responsible ethics committee.

Results

In group 2 there was a significant increase in liver stiffness after food intake at T15, T30, and T45 during inspiration measurements (T0 = 4.0 kPa vs. T15 = 4.9 kPa, difference = 22.5%; T0 = 4.0 kPa vs. T30 = 4.9 kPa difference = 22.5%; T0 = 4.0 kPa vs. T45 = 4.3 kPa difference = 7.5%), as well as during expiration at T15 and T30 (T0 = 4.5 kPa vs. T15 = 5.1 kPa, difference = 14.7%; T0 = 4.5 kPa vs. T30 = 4.9 kPa difference = 7.8%). Whereas in Fontan patients (group 1) liver stiffness did not differ significantly at any time between fasting (T0) and postprandial values. The respiratory maneuvers in the healthy subjects (group 2) differed significantly only before food intake (T0) (group 2: insp = 3.97 kPa vs. exp. = 4.48 kPa difference = 11.3%). In the Fontan group (group 1), there was no significant difference between the respiratory phases at any point. The different age categories showed no significant difference in liver stiffness.

Conclusion

With these results we could demonstrate for the first time that in Fontan patients the time of food intake (i.e., fasting) has no clinical significance for the values obtained in liver elastography. We could also demonstrate that the breathing maneuvers during the examination had only minimal clinical impact on the results of liver elastography in patients with normal circulation and no effect in patients with Fontan-circulation. Consequently, liver elastography for Fontan patients is reliable independently of food intake and breathing maneuvers and can also be performed on younger patients, who are unable to follow breathing commands or longer fasting periods, without any impairment of the results. These results should encourage a routine use of LE in the follow-up of Fontan patients.

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.

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.

Torsion of wandering spleen after Fontan operation in a patient with situs inversus: a rare complication

Torsion of wandering spleen after the Fontan operation with situs inversus is rare.Here, we report the case of a 6-year-old girl with a single ventricle and complete situs inversus who developed torsion of wandering spleen due to splenomegaly caused by post-operative haemodynamics of the Fontan operation. The platelet count was suggested to be useful in predicting splenic torsion.

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.

Semiquantitative characterization of dynamic magnetic resonance perfusion of the liver in pediatric Fontan patients

BACKGROUND

Dynamic contrast-enhanced magnetic resonance imaging (MRI) of the liver in pediatric Fontan patients often shows peripheral reticular areas of hypoenhancement, which has not been studied in detail.

OBJECTIVE

To semiquantitatively score the hepatic MR perfusion abnormality seen in pediatric Fontan patients, and to correlate the perfusion abnormality with functional clinical and hemodynamic parameters.

MATERIALS AND METHODS

All children (< 18 years old) after Fontan palliation with combined clinical cardiac and liver MRI performed between May 2017 and April 2019 were considered for inclusion. A semiquantitative perfusion score was used to assess the severity of the hepatic reticular pattern seen on dynamic contrast-enhanced liver imaging. The liver was divided into four sections: right posterior, right anterior, left medial and left lateral. Each liver section was assigned a score from 0 to 4 depending on the amount of abnormal reticular hypoenhancement. Scoring was assigned for each section of the liver across eight successive dynamic contrast-enhanced modified spoiled gradient echo runs. Scores were correlated with clinical and hemodynamic parameters.

RESULTS

All Fontan children showed hepatic reticular hypoenhancement by MRI, most severe in the early portal venous phase with a median maximum total perfusion abnormality score of 12 (range: 9-14). All perfusion abnormalities progressively resolved during the hepatic venous phase. Perfusion abnormality scores were greatest in the right compared to left hepatic lobes (7 range: [6-8] vs. 5 [range: 3-6], P < 0.01). The maximum left hepatic lobe perfusion abnormality scores were greatest in children with versus without imaging signs of portal hypertension (8 [range: 7-8] vs. 4 [range: 3-5], P < 0.01). High unconjugated bilirubin and low platelets correlated with greater perfusion abnormality (R = 0.450, P = 0.024, and R =  - 0.458, P < 0.01, respectively). Age at MRI, time from Fontan, focal liver lesions and cardiac MRI hemodynamic parameters did not show significant correlations with the severity of the liver perfusion abnormality.

CONCLUSION

All Fontan children have hepatic reticular hypoenhancement abnormalities seen with MRI that are most severe in the right hepatic lobe and universally show gradual resolution through the hepatic venous phase. Perfusion abnormality in the left hepatic lobe is worse in children with portal hypertension.

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.

Blood test assessment of liver ultrasound findings in patients with Fontan surgery

Hepatic complications are common in patients with Fontan surgery. The objective of this observational study is to compare demographic, clinical and blood test data in patients older than 14 years old with a Fontan procedure (cases) and asymptomatic patients with single non-operated restrictive ventricular septal defect (VSD) (controls) and to determine whether there are differences in blood collection and liver disease scores according to the liver ultrasound findings in the group of Fontan patients. The liver findings were classified as mild (normal or heterogeneous echogenicity) and significant (nodular surface, small hyperechoic nodules or hepatocarcinoma). 74 patients (14 patients with a Fontan procedure and 60 patients with a restrictive VSD) were included in the study. Median age was 18 (14-45) years old and 41 patients were males. Fontan patients had significantly lower platelet count, lower mean platelet volume (MPV) and lower glucose levels than patients with single non-operated restrictive VSD. On the contrary, Fontan patients showed higher liver enzymes [aspartate aminotransferase (AST) and alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT)], N-terminal pro-brain natriuretic peptide (NT-pro-BNP) and thyroid-stimulating hormone (TSH) concentrations than patients with restrictive VSD. 4 out of 14 (29%) patients with Fontan operation and significant liver ultrasound findings showed greater number of cardiac surgeries, lower MPV values and higher GGT and TSH levels than Fontan patients with mild findings. In conclusion, Fontan patients showed higher liver enzymes (AST, ALT and GGT) than controls and Fontan patients with significant liver ultrasound findings had higher GGT and TSH concentrations than Fontan patients with mild findings.

Liver abnormalities in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a cardiopulmonary disease with high mortality. In recent years, it has been recognized that PAH is a multi-organ system disease, involving the systemic circulation, kidneys, skeletal muscles, and the central nervous system, among others. Right heart failure produces congestive hepatopathy, a disease state that has direct consequences on liver biochemistry, histology, and systemic glucose and lipid metabolism. This article aims to summarize the consequences of congestive hepatopathy with an emphasis on liver biochemistry, histology, and PAH-targeted therapy. Furthermore, PAH-specific changes in glucose and lipid metabolism will be discussed.

Liver function monitoring in Fontan-procedure patients: audit of current practice across South Wales

The Fontan procedure provides a palliative surgical repair for complex congenital heart disease, but it is associated with many long-term problems, including liver cirrhosis, and hepatocellular carcinoma. The current suggestion from international guidance is that end-organ surveillance should be carried out, with a particular focus on regular blood tests and imaging for liver function. In this study, retrospective analysis was performed on adult patients who had previously had a Fontan operation performed to determine the regularity of end-organ surveillance in regards to their liver function covering the three calendar years from 2016 to 2018, and the first six months of 2019. Eighty-six patients were identified in South Wales monitored by the adult congenital heart disease unit. We found that the number of investigations performed in the first six months of 2019 was comparable to other calendar years in their entirety. Liver function tests had been performed in 57% of patients throughout 2018, with only 8% having had an alpha-fetoprotein taken, and only 9% having had imaging of the liver performed. Over the course of their lifetime, 97% of patients had had a liver function blood test performed at some point, with 17% having had an alpha-fetoprotein taken, and 49% having their liver imaged. In conclusion, end-organ surveillance is an important follow-up for patients with a Fontan circulation, with guidelines proposing yearly blood test and imaging investigations. This study shows the opportunities to improve surveillance in this group of patients to highlight the development of liver cirrhosis, and/or hepatocellular carcinoma.

Surveillance of Fontan Associated Liver Disease in Childhood and Adolescence

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

Fontan-associated liver disease and total cavopulmonary anatomical flow effectors

OBJECTIVE

We investigated a relationship between a composite index comprised of Fontan-circuit anatomical features and hepatic fibrosis scores from biopsy.

METHODS

We identified living extracardiac Fontan patients, ≥7 years old and ≥5 but <20 years postoperative, that underwent cardiac catheterization and transvenous liver biopsy between March 2012 and September 2020. We divided patients into anatomical groups and applied a risk score to each patient. We compared average anatomical risk scores with average hepatic total fibrosis scores by group.

RESULTS

We identified 111 patients that met inclusion criteria. After excluding four patients, we assigned 107 to one of 12 anatomical variant groups (n ≥ 3). For the 107, the average age at liver biopsy was 14 ± 6 years old. Of the 107, 105 (98%) were New York Heart Association Class 1. We found average anatomical risk scores by group correlated with average total fibrosis scores by group (R = 0.8; p = .005). An average Fontan duration to biopsy of 10 ± 1 years was similar for all 12 anatomical groups. We found no other clinical variables, laboratory, or hemodynamic values that trended with anatomical risk scores or hepatic total fibrosis scores.

CONCLUSIONS

In a cohort of relatively young, stable extracardiac Fontan patients, average composite anatomical risk scores strongly correlated with average hepatic total fibrosis scores by anatomical group. These findings suggest that some anatomical variants in extracardiac Fontan patients are associated with higher Fontan-associated liver disease (FALD)-related hepatic total fibrosis scores than others, despite similar Fontan durations.

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.

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.

Patients with Single-Ventricle Physiology over the Age of 40 Years

Background: Single-ventricle physiology (SVP) is associated with significant morbidity and mortality at a young age. However, survival prospects have improved and risk factors for a negative outcome are well described in younger cohorts. Data regarding older adults is scarce. Methods: In this study, SVP patients under active follow-up at our center who were ≥40 years of age at any point between January 2005 and December 2018 were included. Demographic data, as well as medical/surgical history were retrieved from hospital records. The primary end-point was all-cause mortality. Results: Altogether, 49 patients (19 female (38.8%), mean age 49.2 ± 6.4 years) were included. Median follow-up time was 4.9 years (interquartile range (IQR): 1.8–8.5). Of these patients, 40 (81.6%) had undergone at least one cardiac surgery. The most common extracardiac comorbidities were thyroid dysfunction (n = 27, 55.1%) and renal disease (n = 15, 30.6%). During follow-up, 10 patients (20.4%) died. On univariate analysis, renal disease and liver cirrhosis were predictors of all-cause mortality. On multivariate analysis, only renal disease (hazard ratio (HR): 12.5, 95% confidence interval (CI): 1.5–106.3, p = 0.021) remained as an independent predictor. Conclusions: SVP patients ≥40 years of age are burdened with significant morbidity and mortality. Renal disease is an independent predictor of all-cause mortality.

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.

Research priorities in Fontan-associated liver disease

PURPOSE OF REVIEW

Fontan-associated liver disease (FALD) is an emerging condition in patients who have undergone surgical correction of univentricular congenital heart disease. There is little known about the epidemiology of FALD, including risk factors for end-organ failure or hepatocellular carcinoma nor a consensus on surveillance guidelines. Furthermore, there is a need to understand the role of heart versus combined heart-liver transplantation in this population. Research is limited by systemic barriers hindering the ability to track longitudinal FALD outcomes.

RECENT FINDINGS

Nearly all patients post-Fontan develop histological features of FALD as a function of time post-Fontan, regardless of Fontan hemodynamics. In cases of end-organ disease, single-center studies have shown promising outcomes of combined heart-liver transplant in this population, with decreased rates of acute rejection. However, despite the burden of disease, it is not currently possible to identify the population of patients with FALD using existing clinical databases and registries due to a lack of diagnostic codes.

SUMMARY

Strategies proposed to address barriers to understanding FALD include developing appropriate diagnostic and transplant-related codes for existing registries. Efforts should also be targeted at initiating prospective studies to understand recognized comorbidities related to Fontan physiology, guided by a team of multidisciplinary subspecialists.

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.