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

Fontan-Associated Liver Disease

Fontan-associated liver disease (FALD) occurs in all patients who have undergone Fontan palliation for functional single ventricle congenital heart defects. While liver fibrosis is universal in patients who have undergone Fontan palliation, FALD may lead to more serious consequences including portal hypertension, cirrhosis, and hepatocellular carcinoma. Scientific studies of the pathophysiology and clinical management of FALD have been limited to date by the heterogeneous nature of the disease, relatively small population of patients with Fontan physiology, and inaccuracy of noninvasive staging tests. As survival after the Fontan procedure improves, the population of adults with Fontan physiology is growing, leading to more severe extracardiac complications related to the Fontan circulation and growing demand for heart and liver transplantation. The accurate evaluation, staging, and management of FALD comprises a clinical challenge which requires expert multidisciplinary input.

Ultrasound-MRI Agreement in Individuals Undergoing Surveillance of Fontan-associated Liver Disease

OBJECTIVE

To assess agreement between abdominal ultrasound and MRI for the detection of focal liver lesions and manifestations of portal hypertension in patients with Fontan circulation.

MATERIALS AND METHODS

To perform this single-center, retrospective study, we identified patients with Fontan circulation who underwent clinical abdominal ultrasound and MRI examinations within ±12 months between January 1, 2018 and June 30, 2023. Imaging reports were reviewed for the presence of liver lesions (specifically noting lesions >1 cm and radiologist-indicated suspicious lesions), features of portal hypertension (ie, presence of ascites and spleen length), abnormal liver contour, and liver stiffness. Intermodality agreement, sensitivity and specificity of ultrasound relative to MRI, and Spearman correlation were used to compare ultrasound and MRI measurements. Follow-up of detected lesions was also performed using electronic health records.

RESULTS

There were 58 patients included. Agreement between MRI and ultrasound for the findings of Fontan-associated liver disease (FALD) was as follows: presence of a liver lesion of any size [k = 0.20 (95% CI: 0.08 to 0.32)], presence of a liver lesion >1 cm [k = 0.43 (95% CI: 0.18 to 0.68)], radiologist-indicated suspicious liver lesion(s) [k = 0.07 (95% CI: -0.13 to 0.27)], presence of ascites [k = 0.57 (95% CI: 0.32 to 0.81)], abnormal liver contour [k = 0.31 (95% CI: 0.03 to 0.59)], and spleen length [intraclass correlation coefficient = 0.81 (95% CI: 0.58 to 0.92)]. Sensitivity and specificity of ultrasound using MRI as the reference standard were as follows: 34% (95% CI: 20% to 50%) and 100% (95% CI: 77% to 100%) for the presence of a liver lesion of any size, and 39% (95% CI: 17% to 64%) and 98% (95% CI: 87% to 100%) for the presence of a liver lesion >1 cm. There was a poor correlation between ultrasound and MRI liver stiffness measurements [rho = 0.22 (95% CI: -0.14 to 0.53); P = 0.23]. Of 44 patients with liver lesions, 3 (6.8%) had biopsy-confirmed hepatocellular neoplasms, including 2 adenomas and 1 hepatocellular carcinoma. All 3 lesions were detected by both MRI and ultrasound.

CONCLUSIONS

There is poor to fair agreement between ultrasound and MRI for detecting manifestations of FALD, with ultrasound having poor sensitivity compared with MRI. While ultrasound detected all 3 clinically important liver lesions in our study, our results raise questions about whether ultrasound is an appropriate screening tool for FALD in patients post-Fontan.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

Comprehensive Multiomic Analysis Reveals Metabolic Reprogramming Underlying Human Fontan-Associated Liver Disease

BACKGROUND

The Fontan operation is the current standard of care for single-ventricle congenital heart disease. Almost all patients with Fontan operation develop liver fibrosis at a young age, known as Fontan-associated liver disease (FALD). The pathogenesis and mechanisms underlying FALD remain little understood, and there are no effective therapies. We aimed to present a comprehensive multiomic analysis of human FALD, revealing the fundamental biology and pathogenesis of FALD.

METHODS AND RESULTS

We recently generated a single-cell transcriptomic and epigenomic atlas of human FALD using single-nucleus multiomic RNA sequencing and assay for transposase-accessible chromatin using sequencing, which uncovered substantial metabolic reprogramming. Here, we applied liquid chromatography-mass spectrometry-based untargeted metabolomics to unveil the metabolomic landscape of human FALD, using liver samples/biopsies from age- and sex-matched donors and patients with FALD (n=12 per group). Results were integrated with liver single-nucleus multiomic RNA sequencing and assay for transposase-accessible chromatin using sequencing and serum metabolomics data to present a comprehensive multiomic atlas of FALD.We discovered significant metabolic abnormalities in livers of adolescent patients with Fontan circulation, particularly amino acid metabolism, peroxisomal fatty acid oxidation, cytochrome P450 system, glycolysis, tricarboxylic acid cycle, ketone body metabolism, and bile acid metabolism. Integrated analyses with liver single-nucleus multiomic RNA sequencing and assay for transposase-accessible chromatin using sequencing results unveiled potential underlying mechanisms of these metabolic changes. Comparison with serum metabolomics data indicate that liver metabolic reprogramming contributes to circulatory metabolomic changes in FALD. Furthermore, comparison with metabolomics data of human metabolic dysfunction-associated fatty liver disease and metabolic dysfunction-associated steatohepatitis highlighted dysregulated amino acid metabolism as a common metabolic abnormality.

CONCLUSIONS

Our comprehensive multiomic analyses reveal new insights into the fundamental biology and pathogenesis mechanisms of human FALD.

Fontan-Associated Liver Disease (FALD) in the EUROFontan Experience. An Insight into European Awareness

Fontan-Associated Liver Disease (FALD) is a dramatically emerging problem even if not precisely defined in term of debated diagnosis and surveillance protocols. We analyze FALD prevalence, clinical impact and implications in a European cohort of patients. It's a retrospective observational multicenter study including Fontan patients operated between 1990 and 2022. Anatomical, clinical, surgical and liver-related data were collected, defining FALD as a spectrum of time-related structural-functional liver modifications due to congestive hepatopathy (from mild liver fibrosis to liver cirrhosis and hepatocellular carcinoma) diagnosed through multiparametric evaluations. 14 centers routinely conducted liver assessment after Fontan completion. Out of 2141 patients, 343 (16%) were diagnosed with FALD (M/F = 198/145; median age 18 years, IQR 15-26) with a median follow-up time of 14 years (IQR 9-20) from Fontan surgery. Among these, there were 19 (5.5%) deaths, 5 (26.3%) of whom related to advanced liver disease/cancer. FALD showed no significant association with gender (p = 0.4, adjusted p-value = 0.5), dominant ventricular morphology (p = 0.060, adjusted p-value = 0.086) nor surgery type (p = 0.3, adjusted p-value = 0.4). Significant association emerged between FALD and fenestration absence (p < 0.001, adjusted p-value < 0.001), systemic ventricular (p < 0.001, adjusted p-value < 0.001) and atrio-ventricular valve (p < 0.001) dysfunction, III-IV NYHA classes (p < 0.001, adjusted p-value < 0.001), tachyarrhythmias (p < 0.001) and liver stiffness ≥ 22 kPa on transient elastography (p < 0.001, adjusted p-value < 0.001). The analysis demonstrated no significant association between FALD and abnormal liver function tests (p = 0.2), heart transplantation (p = 0.6, adjusted p-value = 0.6), worse survival (p = 0.38). This study shows significant mortality related to FALD, which is also associated to clinical signs of failing Fontan circulation, stressing the pressing need of universally shared diagnostic criteria and surveillance protocols, to prevent and/or early-identify FALD and its more lethal complications.

Characteristics and Survival Outcomes of Hepatocellular Carcinoma After the Fontan Operation

BACKGROUND

The Fontan operation is a surgical procedure to palliate single ventricle congenital heart disease. Hepatocellular carcinoma (HCC) is a rare complication of Fontan-associated liver disease (FALD).

OBJECTIVES

The authors aim to examine characteristics of individuals with Fontan circulation diagnosed with HCC and to describe tumor characteristics, treatment, and survival outcomes of these patients.

METHODS

This was a multicenter retrospective case-control study of adults with Fontan circulation between 2005 and 2021. HCC cases were included based on histology or imaging-based diagnosis. Controls were randomly selected in a 3:1 ratio from the center in which the case was derived. Descriptive statistics were used to compare groups and Kaplan-Meier survival analysis was performed.

RESULTS

There were 58 cases of HCC diagnosed at a median age of 31 (IQR: 26-38) years. Diagnosis was made at very early or early stage disease in 68%. Compared to controls, cases had higher prevalence of advanced FALD including varices, ascites, splenomegaly, and decreased platelets. Treatment with curative intent (combined heart-liver transplantation, resection, or ablation) was performed in 41%. Survival at 1 year was 78.9% and highest among those diagnosed at very early or early stage. Over half were undergoing active surveillance at diagnosis, which showed a nonsignificant trend toward higher survival (P = 0.088).

CONCLUSIONS

We describe the clinical characteristics, treatment, and survival in patients with FALD-HCC. Results suggest that adults with FALD-HCC diagnosed with early stage disease may have survival benefit. Our findings underscore the importance of HCC screening for early detection in individuals after the Fontan operation.

Non-invasive assessment of severe liver fibrosis in patients with Fontan-associated liver disease: The VALDIG-EASL FONLIVER cohort

BACKGROUND & AIMS

Fontan-type surgery is a palliative procedure for congenital heart disease with univentricular physiology that may, in the long term, lead to advanced chronic liver disease. Herein, we assessed the accuracy of conventional non-invasive models for assessing liver fibrosis in the context of Fontan circulation and developed a new risk score employing non-invasive tools.

METHODS

A prospective, cross-sectional, observational study was conducted across five European centers and encompassing all consecutive adult patients with Fontan circulation, liver biopsy and non-invasive tests (e.g. elastography, APRI, and FIB-4). The primary outcome was the identification of severe liver fibrosis on biopsy. Multivariable logistic regression identified non-invasive predictors of severe fibrosis, leading to the development and internal validation of a new scoring model named the FonLiver risk score.

RESULTS

In total, 217 patients (mean [SD] age, 27.9 [8.9] years; 50.7% males) were included. Severe liver fibrosis was present in 47.9% (95% CI 41.2%-54.5%) and correlated with a lower functional class, protein-losing enteropathy, and compromised cardiopulmonary and systemic hemodynamics. The final FonLiver risk score incorporated liver stiffness measurement using transient elastography and platelet count, and demonstrated strong discrimination and calibration (AUROC of 0.81). The FonLiver risk score outperformed conventional prediction models (e.g. APRI and FIB-4), which all exhibited worse performance in our cohort (AUROC <0.70 for all).

CONCLUSION

Severe liver fibrosis is prevalent in adults following Fontan-type surgery and can be effectively estimated using the novel FonLiver risk score. This scoring system can be easily incorporated into the routine assessment of patients with Fontan circulation.

IMPACT AND IMPLICATIONS

Fontan-type surgery is used as a palliative procedure for congenital heart disease with univentricular physiology that may, in the long term, lead to advanced chronic liver disease. The severity of liver fibrosis progression has been proposed as a surrogate for failing Fontan hemodynamics as well as worse outcomes after heart transplantation. The development of FALD screening protocols would facilitate the early detection of advanced fibrosis and anticipate interventions to optimize the Fontan circulation, thereby improving outcomes. In our international series, we have developed the FonLiver risk score to predict severe fibrosis, that can be easily incorporated into the routine assessment of patients with Fontan circulation.

Impact of ursodeoxycholic acid treatment on Fontan-associated liver disease

BACKGROUND

Fontan-associated liver disease (FALD) is a type of progressive liver fibrosis that occurs following Fontan surgery and can be complicated by hepatocellular carcinoma (HCC). Established treatments for FALD are lacking. Therefore, we investigated the efficacy of ursodeoxycholic acid (UDCA) in patients with FALD.

METHODS

This single-center retrospective study was conducted from 2003 to 2024 and involved 220 patients (103 men, 46.8%) who had been diagnosed with FALD. UDCA was administered to 113 patients presenting with liver or biliary enzyme abnormalities. We evaluated the patients' liver enzyme levels 3, 6, and 12 months after treatment. HCC developed in 10.5% and the mortality rate was 4.5%. Survival and cumulative incidence of HCC were compared between patients with and without UDCA treatment using Kaplan-Meier curves and propensity-matched analysis (n = 68 per group).

RESULTS

UDCA treatment significantly reduced the aspartate aminotransferase (AST), alanine transaminase (ALT), and gamma-glutamyl transferase (GGT) levels at 3 months. The mean pretreatment AST/ALT/GGT levels were 26/22/323 U/L, respectively, and decreased to 19/15/102 U/L at 3 months, 18/12/88 U/L at 6 months, and 16/19/64 U/L at 12 months. However, the total bilirubin level and platelet count did not show significant differences. The survival rate was higher and the HCC rate was lower in patients with than without UDCA treatment. The 5-year incidence rate of HCC was 5.6% in the UDCA group and 24.2% in the untreated group.

CONCLUSIONS

UDCA treatment significantly reduced liver enzyme levels, including GGT, and mitigated the progression of HCC. UDCA may be beneficial for patients with FALD.

A Meta-Analysis of Cumulative Incidence of Hepatocellular Carcinoma After the Fontan Operation

BACKGROUND

Hepatic complications are increasingly recognized after the Fontan operation. The development of hepatocellular carcinoma (HCC) is associated with high mortality when diagnosed, but its incidence and risk factors are poorly understood. We conducted a systematic review and meta-analysis of the cumulative incidence of HCC after Fontan and associated risk factors.

METHODS

We searched PubMed, CINAHL, and MEDLINE databases for articles reporting the cumulative incidence of HCC after Fontan operation on March 21, 2023. A single-arm random effects meta-analysis was conducted to assess cumulative incidence at 10, 20, and 30 years after Fontan. Meta-analysis of the difference of the medians was used to assess the influence of risk factors on the development of HCC.

RESULTS

Four studies including a total of 1320 patients reported cumulative incidence. The cumulative incidence of HCC at 10, 20, and 30 years after Fontan was 0% (95% CI 0.00-0.01), 2% (0.01-0.06), and 7% (0.03-0.17) respectively. Seven studies including 6,250 patients reported overall incidence of HCC and associated risk factors. At a median 18.4 (IQR 11.9-24.9) years of follow-up, incidence of HCC was 2% (0.01-0.04). Only use of anticoagulation was associated with a lower risk of HCC (RR 0.3, 95% CI 0.1-0.88).

DISCUSSION

By 30 years after Fontan, cumulative incidence of HCC is high (7%). Risk of HCC development prior to 10 years post-Fontan is low (0%), though the decision to defer HCC surveillance in this period may require future investigation based on larger studies. Screening with ultrasound every 6 months starting 20 years post-Fontan is reasonable, however, further research regarding timing, cost-effectiveness, additional risk factors associated with HCC risk, and different screening modalities is required.

Importance of gamma-glutamyl transferase elevation in patients with Fontan-associated liver disease

AIM

In patients with Fontan-associated liver disease (FALD), gamma-glutamyl transferase (GGT) levels are often elevated, however, its clinical importance is unclear. We investigated the relationship between the clinical course of FALD and GGT levels.

METHODS

We enrolled 145 patients with FALD who underwent right-heart catheterization (RHC) and visited our department. Ursodeoxycholic acid (UDCA) was administered to 62 of the patients. Patients with GGT levels <50 and ≥50 U/L were compared. Follow-up RHC was undertaken in 76 patients. Cases in which GGT levels decreased by ≥10% or <50 U/L were defined as improved (n = 33).

RESULTS

Patients with GGT levels ≥50 U/L had significantly lower levels of albumin and higher levels of alanine transaminase (ALT) but no significant differences in RHC factors. Over a 4.6-year period, 43.4% showed improvement in GGT levels. Improved cases had significantly lower total bilirubin (1.1 vs. 1.6 mg/dL), AST (22 vs. 28 U/L), and ALT (18 vs. 27 U/L) levels than nonimproved cases (n = 29, p < 0.05), and the change in platelet count (-0.5 vs. -3.0 × 10-4/μL) was significantly lower in the latter (p = 0.03). The improvement rate was significantly higher in UDCA-treated cases (55.2%) with GGT levels ≥50 U/L compared to cases not treated with UDCA (18.2%, p = 0.04).

CONCLUSION

In cases of FALD with no improvement in GGT level, the platelet count decreased over time, suggesting progression of fibrosis. Physicians should be aware of the importance of a high GGT level in patients with FALD.

Evaluation of diagnostic criteria for mild-to-advanced stages of Fontan-associated liver disease: A nationwide epidemiological survey in Japan

AIM

Fontan-associated liver disease (FALD) is a complication after Fontan surgery, and a common cause of liver tumors and cirrhosis. However, no diagnostic criteria for FALD have been established, leading to an underestimation of its prevalence.

METHODS

We conducted a national survey to elucidate the characteristics of FALD by collecting data from high-volume centers managing patients who had undergone the Fontan surgery in Japan. In total, 1168 patients were enrolled in the study. First, we examined typical liver findings on ultrasonography after the Fontan surgery. Next, we proposed diagnostic criteria for FALD and advanced FALD based on blood tests, imaging, liver tumors, and pathological examinations. We investigated the sensitivity of histologically diagnosed FALD and advanced FALD based on criteria for blood or imaging tests.

RESULTS

Hepatomegaly, hepatic venous dilatation, caudate lobe enlargement, splenomegaly, liver atrophy, ascites, hepatocellular carcinoma, and hepatic tumors other than hepatocellular carcinoma were observed in 37.7%, 29.9%, 18.4%, 33.2%, 3.2%, 6.0%, 0.85%, and 10.0% of patients, respectively. Typical ultrasound findings of FALD included hepatomegaly, hepatic vein dilatation, and splenomegaly, reflecting liver congestion. With the progression of fibrosis, caudate lobe enlargement and splenomegaly became more prominent. Based on these findings, we proposed diagnostic criteria for FALD. Using these criteria, FALD was diagnosed in 1014 (86.8%) of the patients, and all patients with a pathological diagnosis of FALD were successfully identified. Eight patients were found to have pathological cirrhosis, and all were diagnosed with advanced FALD using our criteria based on blood tests or imaging.

CONCLUSION

Our diagnostic criteria facilitate detection of FALD or advanced FALD after the Fontan surgery. The accuracy of these criteria should be further evaluated.

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

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

Effect of maneuvers, diuresis, and fluid administration on ultrasound-measured liver stiffness after Fontan

BACKGROUND

To determine the effect of stress maneuvers/interventions on ultrasound liver stiffness measurements (LSMs) in patients with Fontan circulation and healthy controls.

METHODS

In this prospective, IRB-approved study of 10 patients after Fontan palliation and 10 healthy controls, ultrasound 2D shear-wave elastography LSMs were acquired at baseline and after maximum inspiration, expiration, standing, handgrip, aerobic exercise, i.v. fluid (500 mL normal saline) administration, and i.v. furosemide (20 mg) administration. Absolute and percent change in LSM were compared between baseline and each maneuver, and then from fluid infusion to after diuresis.

RESULTS

Median ages were 25.5 and 26 years in the post-Fontan and control groups (p = 0.796). LSMs after Fontan were higher at baseline (2.6 vs. 1.3 m/s) and with all maneuvers compared to controls (all p < 0.001). Changes in LSM with maneuvers, exercise, fluid, or diuresis were not significant when compared to baseline in post-Fontan patients. LSM in controls increased with inspiration (+0.02 m/s, 1.6%, p = 0.03), standing (+0.07 m/s, 5.5%, p = 0.03), and fluid administration (+0.10 m/s, 7.8%, p = 0.002), and decreased 60 minutes after diuretic administration (-0.05 m/s, -3.9%, p = 0.01) compared to baseline. LSM after diuretic administration significantly decreased when compared to after i.v. fluid administration at 30 minutes (-0.79 m/s, -26.5%, p = 0.004) and 60 minutes (-0.78 m/s, -26.2%, p = 0.017) for patients after Fontan and controls at 15 minutes (-0.12 m/s, -8.70%, p = 0.002), 30 minutes (-0.15 m/s, -10.9%, p = 0.003), and 60 minutes (-0.1 m/s, -10.9%, p = 0.005).

CONCLUSIONS

LSM after Fontan is higher with more variability compared to controls. Diuresis is associated with significantly decreased liver stiffness in both patients after Fontan and controls, with the suggestion of a greater effect in Fontan patients.

Thrombocytopenia is Associated with Higher Fontan Pressure and Increased Morbidity in Patients with Fontan Circulation

After the Fontan procedure, patients require lifelong follow-up due to significant late morbidity and mortality. Thrombocytopenia is seen frequently post-Fontan, likely due to secondary hypersplenism from elevated Fontan pressure. We investigated platelet counts in patients with a Fontan circulation and assessed associations with catheterization data and clinical outcomes. This retrospective study included 92 patients (33% female) post-Fontan who had a complete blood count performed between January 2011 and July 2023. The age at evaluation was 24.0 ± 8.9 years. Outcomes measured included elevated Fontan pressure (≥ 15 mmHg), Fontan-associated liver disease (FALD), unscheduled admissions, transplant, and death. Participants with thrombocytopenia (≤ 150,000/µL) had significantly higher rates of elevated Fontan pressure (OR 8.1, 95% CI 1.3-52.7, p = 0.03), FALD (OR 4.1, 95% CI 1.6-10.6, p = 0.004), and unscheduled admissions (362 ± 577 versus 115 ± 185 admissions per 1000 patient-years, p = 0.02). Thrombocytopenia post-Fontan is associated with elevated Fontan pressure, FALD, and increased morbidity. Platelet count could serve as a non-invasive factor in identifying patients at risk of decompensation.

Histopathological Spectrum and Molecular Characterization of Liver Tumors in the Setting of Fontan-Associated Liver Disease

PURPOSE

Univentricular heart is corrected with the Fontan procedure (FP). In the long term, so-called Fontan-associated liver diseases (FALDs) can develop. The aim of this study is to analyze the molecular profile of FALDs.

METHODS

FALDs between January 1990 and December 2022 were reviewed for histology and immunohistochemistry, laboratory data, and images. Targeted next generation sequencing (NGS), performed on the DNA and RNA of both neoplastic and non-lesional liver tissue, was applied.

RESULTS

A total of 31/208 nodules > 1 cm in diameter were identified on imaging, but a liver biopsy was available for five patient demonstrating the following: one hepatocellular adenoma (HA), two hepatocellular carcinomas (HCCs), one fibrolamellar carcinoma (FLC), and one intrahepatic cholangiocarcinoma (ICC). Molecular analysis showed a copy number alteration involving FGFR3 in three cases (two HCCs and one ICC) as well as one HCC with a hotspot mutation on the CTNNB1 and NRAS genes. Tumor mutational burden ranged from low to intermediate. A variant of uncertain significance in GNAS was present in two HCCs and in one ICC. The same molecular profile was observed in a non-lesional liver. A DNAJB1-PRKACA fusion was detected only in one FLC.

CONCLUSIONS

Neoplastic FALDs show some unusual molecular profiles compared with non-Fontan ones. The presence of the same alterations in non-lesional cardiac cirrhosis could contribute to the development of FALD.