Severity of Fontan-Associated Liver Disease Correlates with Fontan Hemodynamics

Quantifying and visualizing abdominal hemodynamics in patients with Fontan circulation by 4D phase-contrast flow magnetic resonance imaging at 1.5 T

BACKGROUND

Liver fibrosis has been recognized as a long-term morbidity associated with Fontan circulation (Fontan-associated liver disease, FALD). The pathophysiology of FALD is not completely understood and abnormal flow dynamics may be associated with this condition. Liver hemodynamics can be quantitatively evaluated with four-dimensional phase-contrast flow magnetic resonance imaging (4D PC flow MRI). The study aimed to evaluate suitability of liver 4D PC flow MRI in Fontan patients and relate flow measurements to normal values and FALD severity.

PATIENTS AND METHODS

Twenty-two Fontan patients were examined by 4D PC flow MRI at 1.5 Tesla to assess mesenteric, portal, splenic, and hepatic venous blood flow. Severity of FALD was graded based on routine screening, including abdominal ultrasound and laboratory tests.

RESULTS

Median age was 18.5 (interquartile range, IQR 15.5-20.2) years. FALD was graded as "none or mild" in 16 and as "moderate to severe" in six cases. Ten patients presented at least one feature of portal hypertension (ascites, splenomegaly, or thrombocytopenia). For the entire cohort, blood flow in the superior mesenteric, splenic, and portal vein was lower than reported in the literature. No significant differences were observed in relation to FALD severity. Features of portal hypertension were associated with a higher splenic vein blood flow (0.34 ± 0.17 vs. 0.20 ± 0.07 l/min, p = 0.046). Splenic vein blood flow was negatively correlated to platelet count (r = -0.590, p = 0.005).

CONCLUSIONS

4D PC flow MRI appears suitable to assess liver hemodynamics in Fontan patients and integration into clinical follow-up might help to improve our understanding of FALD.

Prognostic Indicators of Morbidity and Mortality in Children with Congestive Hepatopathy Presenting with Ascites

Objectives: Congestive hepatopathy is a significant complication for children suffering from right-sided heart disease (RHD). We hypothesize that hospitalized pediatric patients with ascites will have congestive hepatopathy leading to advanced liver disease if their cardiac condition is RHD versus non-right-sided heart disease (NRHD). Methods: This is a retrospective cohort study of pediatric patients who presented with an ascites diagnosis (ICD-10 R18) and at least one cardiac diagnosis. Patient demographics, past medical history, laboratory values, imaging results, calculated clinical scores (e.g., APRI, FIB-4), treatment, length of stay (LOS), and death at hospital discharge were analyzed. Results: Of the 136 patients with ascites, 21 patients presented with a primary cardiac disease (12 in RHD and 9 in NRHD). Of these patients, eight (38%) were female, and nine (43%) were White, seven (33%) were Black, and five (24%) were unknown. The RHD group had a mean age of 5.1 Y (vs. 9.5 Y in NRHD). The mean APRI score in RHD patients was 2.87, and it was 0.85 in NRDH. Treatments were similar, with most patients requiring diuretics (11 RHD (92%) vs. 8 NRDH (89%)); 5 RHD (42%) vs. 4 NRDH (44%) required inotropic support. RHD patients had a longer LOS, with an average of 92 days vs. 52 days for NRDH patients. Overall, each group had one death at discharge (8% RHD vs. 11% NRDH). Conclusions: In the realm of children with ascites, the subset grappling with congestive heart disease paints a unique picture. In this context, ascites stands as an elusive predictor of liver decompensation, defying conventional diagnostic pathways.

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.

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

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

Mitochondrial dysfunction is associated with the severity of liver fibrosis in patients after the Fontan operation

The gold standard for determining the severity of liver disease in Fontan patients is now liver biopsy. Since it is an invasive procedure, this study determined the possibility of applying mitochondrial function from isolated peripheral blood mononuclear cells (PBMCs) as a non-invasive indicator of liver fibrosis. Fontan patients (n = 37) without known liver disease were analysed cross-sectionally. Patients were classified according to their histology using the METAVIR score as follows; F0/F1-no/mild fibrosis; F2-moderate fibrosis; and F3/F4-cirrhosis. Peripheral blood mononuclear cells were assessed for mitochondrial activity and apoptosis. This study did not find any significant differences in cardiac function among the groups according to liver histology. Interestingly, our findings indicated a significant decrease in maximal respiration and spare respiratory capacity, in both the moderate (F2) and cirrhosis (F3/F4) groups compared with the group without significant fibrosis (F0/F1). Moreover, the cirrhosis group exhibited higher levels of apoptosis and lower levels of live cells, compared with both the moderate and no significant fibrosis groups. In conclusion, the degree of liver fibrosis in Fontan patients is strongly correlated with mitochondrial dysfunction in PBMCs. Mitochondrial function and apoptosis could potentially serve as novel markers for tracking the progression of liver fibrosis in these patients.

Significantly elevated hepatic extracellular volume in adult patients with a Fontan circulation and its correlation with impaired functional capacity

Fontan-associated liver disease is a major concern in patients who have undergone the procedure. Regular imaging of the liver is currently recommended for Fontan patients, but not other congenital heart diseases. The extracellular volume (ECV) of the liver obtained during CMR scanning and studies can show the high liver ECV in Fontan patients. However, the correlation between the liver ECV and the functional capacity of Fontan patients has not yet been reported. This study aimed to compare the liver ECV between Fontan patients and other congenital heart diseases with significant pulmonic regurgitation (PR) or tricuspid regurgitation (TR), and to evaluate the correlation between the liver ECV in adult Fontan patients and their functional capacity as well as clinical characteristics. Retrospective analysis of cardiovascular magnetic resonance imaging from patients with history of Fontan surgery between 2017 and 2021 were conducted. The clinical characteristics and liver ECV were evaluated and compared between patients and control group. Functional capacity was evaluated using a 6-min walk distance (6MWD). The correlation between the liver ECV and functional capacity was analyzed. 35 patients were enrolled in the study, including 13 Fontan patients, 12 Ebstein's anomaly or repaired tetralogy of Fallot (rTOF) patients with significant PR or TR, and 10 patients for the control group. The liver ECV were significantly higher in Fontan patients compared with Ebstein's anomaly/rTOF and the control group (41.% in Fontan group, 33.9% in Ebstein's anomaly/rTOF, and 31.7% in control group with p = 0.01 and 0.0008 in Fontan vs. Ebstein's anomaly/rTOF and Fontan vs. control group, respectively). In Fontan patients, there was a significant correlation between the liver ECV and the liver blood biochemistry with r = 0.879, p = 0.01 for AST/ALT ratio and r = 0.65, p = 0.005 for AST. The liver ECV was inversely correlated with the six-minute walk distance (r = -0.55, p = 0.02). The liver ECV in patients who had undergone Fontan operation showed a significantly elevated and has significantly inversed correlation with their functional capacity. These findings indicated that the liver ECV may be a potentialmarker for adverse clinical outcomes. However, due to small size population, further prospective study with larger number of patients may validate this findings.

Are dynamic measurements of central venous pressure in Fontan circulation during exercise or volume loading superior to resting measurements?

BACKGROUND

The main objective measure to assess the health of the Fontan circulation is the pressure measurement of the superior vena cava or pulmonary arteries. We reviewed the literature for benefits of measuring resting pressure in the Fontan circuit and explored whether dynamic measurement by volume loading or exercise has the potential to refine this diagnostic tool.

METHODS

PubMed was searched for articles showing a relationship between resting post-operative central venous pressure or pulmonary artery pressure and Fontan failure. Relationships between post-operative central venous pressure or pulmonary artery pressure and volume loading changes, such as during exercise or volume loading during cardiac catheterization, were also queried.

RESULTS

A total of 44 articles mentioned relationships between resting central venous pressure or pulmonary artery pressure and Fontan failure. Only 26 included an analysis between the variables and only seven of those articles found pressure to be predictive of Fontan failure. Ten articles examined the relationship between exercise or volume loading and outcomes and demonstrated a large individual variation of pressures under these dynamic conditions.

CONCLUSIONS

Based on current literature, there is not a lot of strong evidence to show that elevated resting central venous pressure or pulmonary artery pressure is predictive of Fontan failure. Some individuals experience dramatic increases in central venous pressure or pulmonary artery pressure under increased loading conditions with exercise or bolus fluid infusion, while others experience increases closer to that of a healthy control population. Further studies are needed to examine whether more dynamic and continuous monitoring of systemic venous pressures might better predict outcomes in patients with Fontan circulation.

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.

Severe Fontan-Associated Liver Disease and Its Association With Mortality

Background Data are rare about the incidence of severe Fontan-associated liver disease (FALD) and its association with mortality. We sought to: (1) estimate the probability of developing severe FALD in patients who undergo the Fontan procedure (Fontan patients), compared with severe liver complications in patients with a ventricular septal defect; (2) assess the severe FALD-mortality association; and (3) identify risk factors for developing severe FALD. Methods and Results Using the Quebec Congenital Heart Disease database, a total of 512 Fontan patients and 10 232 patients with a ventricular septal defect were identified. Kaplan-Meier curves demonstrated significantly higher cumulative risk of severe FALD in Fontan patients (11.95% and 52.24% at 10 and 35 years, respectively), than the risk of severe liver complications in patients with a ventricular septal defect (0.50% and 2.75%, respectively). At 5 years, the cumulative risk of death was 12.60% in patients with severe FALD versus 3.70% in Fontan patients without FALD (log-rank P=0.0171). Cox proportional hazard models identified significant associations between the development of severe FALD and congestive heart failure and supraventricular tachycardia, with hazard ratios (HRs) of 2.36 (95% CI, 1.38-4.02) and 2.45 (95% CI, 1.37-4.39), respectively. More recent Fontan completion was related to reduced risks of severe FALD, with an HR of 0.95 (95% CI, 0.93-0.97) for each more recent year. Conclusions This large-scale population-based study documents that severe FALD in Fontan patients was associated with a >3-fold increase in mortality. The risk of FALD is time-dependent and can reach >50% by 35 years after the Fontan operation. Conditions promoting poor Fontan hemodynamics were associated with severe FALD development.

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.

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.

Issues in multi-organ transplantation of the liver with kidney or heart in polycystic liver-kidney disease or congenital heart disease: Current practices and immunological aspects

Solid organ transplantation has become an integral part of the management of patients with end-stage diseases of the kidney, liver, heart and lungs. Most procedures occur in isolation, but multi-organ transplantation of the liver with either the kidney or heart has become an option. As more patients with congenital heart disease and cardiac cirrhosis survive into adulthood, particularly after the Fontan procedure, liver transplant teams are expected to face questions regarding multi-organ (heart-liver) transplantation. Similarly, patients with polycystic kidneys and livers may be managed by multi-organ transplantation. Herein, we review the indications and outcomes of simultaneous liver-kidney transplantation for polycystic liver-kidney disease, and discuss the indications, timing and procedural aspects of combined heart-liver transplantation. We also summarise the evidence for, and potential mechanisms underlying, the immunoprotective impact of liver allografts on the simultaneously transplanted organs.

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.

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.

Functional hepatic deterioration determined by 13C-methacetin breath test is associated with impaired hemodynamics and late Fontan failure in adults

Background

Despite improved survival a substantial number of Fontan patients eventually develop late failure. Fontan-associated liver disease (FALD) is the most frequent end-organ dysfunction. Although impaired hemodynamics and Fontan failure correlate with FALD severity, no association between hepatic functional metabolic impairment and Fontan hemodynamics has been established.

Hypothesis

Metabolic liver function measured by liver maximum function capacity test (LiMAx®) correlates with Fontan hemodynamics and Fontan failure.

Methods

From 2020 to 2022, 58 adult Fontan patients [median age: 29.3 years, IQR (12.7), median follow-up time after Fontan operation: 23.2 years, IQR (8.7)] were analyzed in a cross-sectional study. Hemodynamic assessment included echocardiography, cardiopulmonary exercise testing and invasive hemodynamic evaluation. Fontan failure was defined based on commonly applied clinical criteria and our recently composed multimodal Fontan failure score.

Results

LiMAx® test revealed normal maximum liver function capacity in 40 patients (>315 μg/h^*kg). In 18 patients a mild to moderate impairment was detected (140–314 μg/h^*kg), no patient suffered from severe hepatic deterioration (≤ 139 μg/kg^*h). Fontan failure was present in 15 patients. Metabolic liver function was significantly reduced in patients with increased pulmonary artery pressure (p = 0.041. r = −0.269) and ventricular end-diastolic pressure (p = 0.033, r = −0.325), respectively. In addition, maximum liver function capacity was significantly impaired in patients with late Fontan failure (289.0 ± 99.6 μg/kg^*h vs. 384.5 ± 128.6 μg/kg^*h, p = 0.007).

Conclusion

Maximum liver function capacity as determined by LiMAx® was significantly reduced in patients with late Fontan failure. In addition, elevated pulmonary artery pressure and end-diastolic ventricular pressure were associated with hepatic functional metabolic impairment.

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.

QRS fragmentation and prolongation as predictors of exercise capacity in patients after Fontan palliation

INTRODUCTION

Patients with Fontan anatomy are at increased risk for exercise intolerance and early morbidity and mortality. QRS complex fragmentation (fQRS) and prolongation have been studied in multiple heart diseases, but their clinical importance is unknown in the Fontan population.

METHODS

A retrospective cross-sectional study was performed. ECGs were evaluated for QRS prolongation (>98 %ile for age) and fQRS [ ≥3 R-waves/ notches in the R/S complex (more than 2 in RBBB) in ≥2 contiguous leads]. The primary outcome measures was CPET performance.

RESULTS

Ninety patients (median age 18 years, 57% male, 59% RV dominant) were included; 13% had fQRS and 31% had prolonged QRS. Demographically, patients with fQRS or prolonged QRS were like those without. Peak VO2 (64% vs 63%, p 0.45), VE/VCO2 slope (85% vs 88%, p = 0.74), and O2 pulse (149% vs 129%, p = 0.83) were similar in the fQRS group versus those without. Upon multi-variable regression, body mass index (β = -0.38, p < 0.01) and QRS duration (β = -0.29, p < 0.01) were independently associated with % predicted VO2; fQRS was not. Lower cardiac index (2.2 vs 2.8 L/min/m2, p = 0.03) and higher ventricular end-diastolic pressure (13 vs 10 mmHg, p = 0.02) was seen with fQRS.

CONCLUSIONS

QRS fragmentation is present in patients with Fontan physiology. fQRS showed no association with CPET performance but was related to invasive hemodynamic markers of ventricular performance. QRS duration may be a better predictor of exercise function following Fontan. This article is protected by copyright. All rights reserved.

Serial T2-Weighted Thoracic and Abdominal Lymphatic Imaging in Fontan Patients—New Insights into Dynamics of Lymphatic Abnormalities after Total Cavopulmonary Connection

Lymphatic congestion in single-ventricle patients has been associated with increased morbidity and poor outcomes. Little is known about the dynamics of lymphatic abnormalities over time, on their association with clinical presentation or response to catheter interventions. This retrospective, single-center study describes Fontan patients who underwent at least two magnetic resonance imaging (MRI) studies. T2-weighted lymphatic imaging was used to classify thoracic and abdominal (para-aortic and portal-venous) lymphatic abnormalities. The relationship between lymphatic congestion and hemodynamic changes after cardiac catheter interventions, clinical presentation and MRI data was analyzed. A total of 33 Fontan patients underwent at least two cardiac MRI studies. Twenty-two patients had two, eight had three and three had four lymphatic imaging studies (total of 80 MRIs studies). No significant changes in lymphatic classification between MRI 1 and 2 were observed for thoracic (p = 0.400), para-aortic (0.670) and portal-venous (p = 0.822) abnormalities. No significant correlation between lymphatic classification and hemodynamic changes after intervention or MRI parameters was found. This study illustrates thoracic and abdominal lymphatic abnormalities in serial T2-weighted imaging after Fontan. Fontan patients did not demonstrate significant changes in their lymphatic perfusion, despite clinical or hemodynamic changes. We assume that lymphatic congestion might develop after total cavopulmonary connection (TCPC) and remain relatively stable, despite further intervention targeting hemodynamic parameters.

Screening modalities for the diagnosis of Fontan-associated liver disease: evidence from the past for future development

Approximately 70,000 patients who have undergone the Fontan operation worldwide survive into adulthood, however the majority of these patients are faced with long-term post-operative complications due to specific hemodynamic changes. Fontan-associated liver disease (FALD) is a challenging complication characterized by various spectra. Of these, liver congestion and liver fibrosis potentially lead to cirrhosis and liver nodules. The most serious condition associated with the development of liver nodules is hepatocellular carcinoma. Various non-invasive modalities including blood tests, ultrasound scans of the upper abdomen, ultrasound elastography of the liver, computed tomography scans, magnetic resonance imaging and magnetic resonance elastography of the liver have been used as alternatives to liver biopsies for FALD assessment in post-Fontan patients. To date, a detailed understanding of the pathophysiology and natural history of these patients, and the most appropriate modality for the effective investigation of this condition is incomplete. In this comprehensive review, reports regarding the currently available screening modalities used in the detection of FALD are summarized and discussed. The findings of this review, including identification of any current knowledge gaps, can pave the way for the development of effective future strategies in the surveillance and ultimately the treatment of post-Fontan patients.

A Multimodal Score Accurately Classifies Fontan Failure and Late Mortality in Adult Fontan Patients

Objectives

Despite the outstanding success of the Fontan operation, it is a palliative procedure and a substantial number of patients experience late failure of the Fontan circulation. Clinical presentation and hemodynamic phenotypes of Fontan failure are considerably variable. While various parameters have been identified as risk factors for late Fontan failure, a feasible score to classify Fontan failure and possibly allow timely risk stratification is lacking. Here, we explored the possibility of developing a score based on hemodynamic, clinical and laboratory parameters to classify Fontan failure and mortality.

Methods

We performed a retrospective study in our cohort of adult Fontan patients from two institutions [n = 198, median follow-up after Fontan 20.3 (IQR 15.6–24.3) years], identifying those patients with clinical Fontan failure (n = 52, 26.3%). Various hemodynamic, echocardiographic, laboratory and clinical data were recorded and differences between patients with and without Fontan failure were analyzed. We composed a Fontan Failure Score containing 15 parameters associated with Fontan failure and/or mortality and assessed its accuracy to discriminate between patients with and without late Fontan failure as well as late mortality and survival.

Results

Late failure occurred at a median of 18.2 (IQR 9.1–21.1) years after Fontan completion. Mortality associated with Fontan failure was substantial (25/52, 48.1%) with freedom of death/transplantation/take-down of 64% at 5 years and 36% at 10 years after onset of Fontan failure, respectively. Patients with Fontan failure had a significantly higher median Fontan Failure Score compared to non-failing Fontan patients [8 points (IQR 5–10) vs. 2 points (IQR 1-5), p < 0.001]. The score accurately classifies Fontan failure as well as mortality as assessed with receiver operating characteristic analysis. Area under the curve of the Fontan Failure Score was 0.963 (95% CI 0.921; 0.985, p < 0.001) to discriminate failure and 0.916 (95% CI 0.873; 0.959, p < 0.001) to classify mortality.

Conclusion

We have developed an uncomplex yet remarkably accurate score to classify Fontan failure and late mortality in adult Fontan patients. Prospective validation and most likely refinement and calibration of the score in larger and preferably multi-institutional cohorts is required to assess its potential to predict the risk of Fontan failure and late mortality.

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

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

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

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

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

Late Fontan failure in adult patients is predominantly associated with deteriorating ventricular function

BACKGROUND

The Fontan operation is a palliative procedure and a substantial number of patients eventually experiences late Fontan circulation failure. Previous concepts of Fontan failure implicate increasing pulmonary vascular resistance (PVR) as a key contributor to late circulatory failure. However, data to support this assumption are sparse. We sought to characterize longitudinal hemodynamic and echocardiographic findings in adult failing Fontan patients.

METHODS

We performed a retrospective cohort study in adult Fontan patients, identifying patients with Fontan failure. Hemodynamic, echocardiographic and clinical data were recorded.

RESULTS

Of 173 adult patients (median follow-up after Fontan 20.2 years [IQR 15.7-24.3]), 48 (28%) showed signs of clinical Fontan failure. Thirty-seven patients (77.1%) exhibited ventricular dysfunction (systolic dysfunction defined by ejection fraction ≤45%, n = 22, or diastolic dysfunction defined by systemic ventricular end-diastolic pressure (SVEDP) ≥12 mmHg, n = 15). Elevated indexed PVR (≥2.5 WU*m²) was only observed in 9 (18.8%) patients. Ejection fraction declined from 60% [IQR 55-65] to 47% [IQR 35-55] during follow-up (p < 0.001). Mean pulmonary artery pressure and SVEDP increased from 11 mmHg [IQR 9-15] to 15 mmHg [IQR 12-18] and from 7 mmHg [IQR 4-10] to 11 mmHg [IQR 8-15] (both p < 0.001), respectively, while indexed PVR did not change significantly (2.1 [IQR 1.1-2.4] vs. 1.7 [IQR 1.1-2.5] WU*m², p = 0.949). Fontan failure-associated mortality during follow-up was substantial (23/48; 48%).

CONCLUSIONS

Systolic and diastolic ventricular dysfunction are frequent features in late Fontan failure in adults, while increases in PVR were rarely observed. The intricate interplay between hemodynamic compromises in Fontan failure deserves further research to optimize treatment strategies and outcome.

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.

Correlation of exercise-induced peripheral venous hypertension with exercise intolerance in patients with Fontan circulation

Owing to the absence of a sub-pulmonary ventricle, the central venous pressure rises in patients with Fontan circulation. During exercise, central venous pressure may rise further to increase the systemic ventricular preload and cardiac output. We performed a single-centre prospective trial of cardiopulmonary exercise test while monitoring peripheral venous pressure which strongly correlates with central venous pressure. The objective of this study was to test the hypothesis that peripheral venous pressure at peak exercise inversely correlates with exercise capacity in patients with Fontan circulation. Seventeen patients following Fontan operation performed cardiopulmonary exercise test while monitoring peripheral venous pressure. Peak oxygen uptake, heart rate reserve, peak oxygen pulse (divided by body surface area), and peripheral venous pressure at peak exercise were measured. Correlations of peripheral venous pressure at peak exercise with the peak oxygen uptake, heart rate reserve, and peak oxygen pulse were evaluated. The peripheral venous pressure at peak exercise inversely correlated with the peak oxygen uptake (R = -0.66, p < 0.01), heart rate reserve (R = -0.6, p < 0.05), and peak oxygen pulse (R = -0.48, p < 0.05). Exercise-induced peripheral venous hypertension correlates with exercise intolerance in patients with Fontan circulation. Peak oxygen uptake is a useful index for evaluating the status of congestion in the daily life of patients with Fontan circulation.

Role of Transient Elastography to Stage Fontan-Associated Liver Disease (FALD) in Adults with Single Ventricle Congenital Heart Disease Correction

Fontan-associated liver disease (FALD) is an arising clinical entity that can occur long after a successful Fontan operation for correction of single ventricle (SV) congenital heart disease (CHD). Occurrence of FALD is characterized by liver cirrhosis and other hepatic complications, and determinates an increased morbidity and mortality. Currently, there is no consensus on how to stage FALD. We report here our experience by an observational study in 52 patients with SV-CHD after Fontan operation that were recruited through a period of 36 ± 9.3 months. All cases underwent lab tests and liver and cardiac imaging evaluation, including liver stiffness (LS) measurement by transient elastography (TE) (FibroScan®). According to selective criteria for liver disease, we identified 23/43 (53.5%) cases with advanced FALD that showed: older age (p < 0.05), larger hepatic and cava veins diameter (p < 0.05), worsened NYHA class (p < 0.05), abnormal lymphocytes (p < 0.01), platelet count (p < 0.05), and GGT, prothrombin time (INR), albumin and cystatin C levels (p < 0.05), with respect to cases without advanced FALD. LS values were significantly increased in cases with advanced FALD, at cut-off values higher than 22 kPa (p < 0.001). LS, and its combined score with spleen diameter and platelet count (LSPS) successfully helped to detect 100% of cases with portal hypertension (p < 0.001). In conclusion, LS can be effective to stage FALD and to uncover cases with severe risk of complications, avoiding higher morbidity and mortality related to advanced FALD.

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

Purpose

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

Methods

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

Results

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

Conclusion

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

Supplementary Information

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

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.

Hepatic magnetic resonance T1-mapping and extracellular volume fraction compared to shear-wave elastography in pediatric Fontan-associated liver disease

BACKGROUND

Children with Fontan circulation are at risk of developing hepatic fibrosis/cirrhosis. Reliable noninvasive monitoring techniques are lacking or under development.

OBJECTIVE

To investigate surrogate indicators of hepatic fibrosis in adolescents with Fontan circulation by evaluating hepatic magnetic resonance (MR) T1 mapping and extracellular volume fraction measurements compared to US shear-wave elastography.

MATERIALS AND METHODS

We analyzed hepatic native T1 times and extracellular volume fractions with modified Look-Locker inversion recovery. Liver stiffness was analyzed with shear-wave elastography. We compared results between 45 pediatric patients ages 16.7±0.6 years with Fontan circulation and 15 healthy controls ages 19.2±1.2 years. Measurements were correlated to clinical and hemodynamic data from cardiac catheterization.

RESULTS

MR mapping was successful in 35/45 patients, revealing higher hepatic T1 times (774±44 ms) than in controls (632±52 ms; P<0.001) and higher extracellular volume fractions (47.4±5.0%) than in controls (34.6±3.8%; P<0.001). Liver stiffness was 1.91±0.13 m/s in patients vs. 1.20±0.10 m/s in controls (P<0.001). Native T1 times correlated with central venous pressures (r=0.5, P=0.007). Native T1 was not correlated with elastography in patients (r=0.2, P=0.1) or controls (r = -0.3, P=0.3). Extracellular volume fraction was correlated with elastography in patients (r=0.5, P=0.005) but not in controls (r=0.2, P=0.6).

CONCLUSION

Increased hepatic MR relaxometry and shear-wave elastography values in adolescents with Fontan circulation suggested the presence of hepatic fibrosis or congestion. Central venous pressure was related to T1 times. Changes were detected differently with MR relaxometry and elastography; thus, these techniques should not be used interchangeably in monitoring hepatic fibrosis.

Evaluation of Fontan failure by classifying the severity of Fontan-associated liver disease: a single-centre cross-sectional study

OBJECTIVES

Fontan-associated liver disease (FALD) is a hallmark of the failing Fontan circulation, but no general classification of FALD severity exists. In this study, we propose a scoring system to grade the severity of FALD and analyse its applicability for evaluation of Fontan failure.

METHODS

From 2017 to 2019, a total of 129 successive Fontan patients received a comprehensive hepatic assessment. The FALD score was based on results from laboratory testing, hepatic ultrasound and transient elastography by assigning scoring points for each abnormality detected. FALD severity was graded mild, moderate and severe. Haemodynamic assessment was performed using echocardiography, cardiopulmonary exercise testing and catheterization.

RESULTS

FALD was graded absent/ mild, moderate and severe in 53, 26 and 50 patients, respectively. Cardiopulmonary capacity was significantly impaired in patients with severe FALD compared to patients with absent/mild FALD (P = 0.001). The FALD score significantly correlated with pulmonary artery pressure (P = 0.001), end-diastolic ventricular pressure (P < 0.001), hepatic venous pressure (P = 0.004) and wedged hepatic venous pressure (P = 0.009). Fontan failure was present in 21 patients. FALD was graded moderate in 2 and severe in 19 of these patients. The FALD score accurately discriminated patients with and without Fontan failure (sensitivity 90.5%, specificity 71.3%).

CONCLUSIONS

The FALD score significantly correlates with impaired Fontan haemodynamics. A cut-off value ≥6.0 has a high diagnostic accuracy in detecting Fontan failure.

CLINICAL TRIAL REGISTRY

DRKS (GCTR, German clinical trial registry).

CLINICAL TRIAL REGISTRATION NUMBER

DRKS00015039.

Imaging of Fontan-associated liver disease

The Fontan operation has dramatically altered the natural history of functionally single ventricle congenital heart disease. Patients who have undergone the Fontan operation are living longer and, thus, noncardiac morbidity resulting from the Fontan operation is increasingly being recognized. Fontan-associated liver disease (FALD), one of the chief morbidities following the Fontan operation, is believed to be a multifactorial process that manifests as hepatic congestion and fibrosis, portal hypertension, and development of focal liver lesions, including malignant tumors. This article reviews the imaging findings of FALD in the pediatric and young adult population, reviews the literature related to the imaging of FALD and discusses possible screening algorithms for this population. The need for further research to better understand the causes of FALD, to establish if early liver stiffness measurements (or their change over time) predict long-term outcomes and complications, and to define optimal liver screening procedures is highlighted.