End-organ consequences of the Fontan operation: liver fibrosis, protein-losing enteropathy and plastic bronchitis

Advances in Diagnostic and Interventional Catheterization in Adults with Fontan Circulation

Over the past five decades, the Fontan procedure has been developed to improve the life expectancy of patients with congenital heart defects characterized by a functionally single ventricle. The Fontan circulation aims at redirecting systemic venous return to the pulmonary circulation in the absence of an impelling subpulmonary ventricle, which makes this physiology quite fragile and leads to several long-term complications. Despite the importance of hemodynamic assessment through cardiac catheterization in the management and follow-up of these patients, a thorough understanding of the ultimate functioning of this type of circulation is lacking, and the interpretation of the hemodynamic data is often complex. In recent years, new tools such as combined catheterization with cardiopulmonary exercise testing have been incorporated to improve the understanding of the hemodynamic profile of these patients. Furthermore, extensive percutaneous treatment options have been developed, addressing issues ranging from obstructive problems in Fontan pathway and acquired shunts through compensatory collaterals to the percutaneous treatment of lymphatic circulation disorders and transcatheter edge-to-edge repair of atrioventricular valves. The aim of this review is to detail the various tools used in cardiac catheterization for patients with Fontan circulation, analyze different percutaneous treatment strategies, and discuss the latest advancements in this field.

Heart Transplantation Following Fontan Failure: Long-Term Survival Analysis

Objectives: Fontan circulation presents significant challenges for patients with congenital heart disease, often necessitating heart transplantation (HTX) due to deteriorating functionality across multiple organ systems. However, the impact of prior Fontan palliation on HTX outcomes remains poorly understood, with early mortality rates suggesting a heightened risk. The aim of our study is to evaluate the long-term results after heart transplantation in patients with univentricular congenital heart disease previously palliated with Fontan circulation. Methods: A retrospective analysis was conducted on patients who underwent HTX for congenital heart disease. Patients were categorized into two groups based on the pre-HTX circulation pathway: the Failing Fontan Group (FFG) and the Biventricular Congenital Group (BCG). Data were collected from patients between 1987 and 2018. Early and late outcomes, including survival rates, were assessed and critically analyzed. Results: Of the 66 patients, 29 (43%) had a failing Fontan palliation (FFG), and 37 had biventricular congenital diseases (BCG) before heart transplantation. Early mortality (30-day) was not statistically different between the two group. The overall survival rate was 82.6 ± 13.9% at 1 year, 79.0 ± 14.9% at 5 years, 67.2 ± 17.6% at 10 years and 63.2 ± 18.2 ± at 15 years for the FFG, and 86.1 ±11.4% at 1 year, 79.5 ± 13.7% at 5 years, 75.7 ± 14.9% at 10 years, 75.7 ± 14.9% at 15 years for the BCG, with no statistically significant difference (Mantel Cox p value: 0.69, 0.89, 0.52 and 0.39, respectively). Regarding Cox-regression analysis, the long-term survival rate was not affected either by previous Fontan surgery or by the era of heart transplantation (before vs. after the year 2000). Conclusions: Although heart transplantation after Fontan palliation showed a higher risk in the early post-operative period, the medium- and long-term survival rates are comparable with biventricular circulation patients. Despite the failing Fontan patients being a challenging set of candidates for transplantation, it is a reasonable option in their treatment.

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.

Clinical and invasively-measured predictors of high exercise capacity in Fontan patients

INTRODUCTION

Fontan patients have variable exercise capacity. Contemporary understanding as to which factors predict high tolerance is limited.

METHODS

Records from the Ahmanson/University of California, Los Angeles Adult Congenital Heart Disease Center were reviewed for adult Fontan patients who underwent CPET. Patients were considered "high performers" if their maximum oxygen uptake (VO2 max/kg)-predicted was greater than 80%. Cross-sectional clinical, hemodynamic, and liver biopsy data was gathered. High-performers were compared to control patients across these parameters via associations and regression.

RESULTS

A total of 195 adult patients were included; 27 patients were considered "high performers". They had lower body mass indices (BMI, p < 0.001), mean Fontan pressures (p = 0.026), and cardiac outputs (p = 0.013). High performers also had higher activity levels (p < 0.001), serum albumin levels (p = 0.003), non-invasive and invasive systemic arterial oxygen saturations (p < 0.001 and p = 0.004), lower New York Heart Association (NYHA) heart failure class (p = 0.002), and were younger at Fontan completion (p = 0.011). High performers had less severe liver fibrosis (p = 0.015). Simple regression found Fontan pressure, non-invasive O2 saturation, albumin level, activity level, age at Fontan surgery, NYHA class, and BMI to predict significant changes in VO2 max/kg %-predicted. These associations persisted in multiple regression for non-invasive O2 saturation, NYHA class II, activity level, and BMI.

CONCLUSIONS

Thin Fontan patients who exercise more had better exercise capacity, Fontan hemodynamic profiles, and less liver fibrosis.

Diastolic myocardial mechanics and their relation to ventricular filling pressures and postoperative course in functionally single ventricles

Diastolic dysfunction affects clinical outcomes in patients with a functionally single ventricle (FSV). The objective of this work is to study the association of ventricular mechanics and interventricular dependence on diastolic parameters and early post-Fontan outcomes. Sixty-one patients with FSV underwent echocardiography, cardiac catheterization, and magnetic resonance imaging on the same day before or after the Fontan procedure. Echocardiographic diastolic parameters, ventricular mass, and incoordinate wall motion, defined by the number of dyskinetic segments or by the lateral wall delay, were determined and studied for relationships with invasively measured hemodynamics and early postoperative Fontan course. In subjects with a sizable secondary ventricle, incoordinate motion was additionally analyzed at the left- and right-sided ventricular free walls. Resting ventricular end-diastolic pressure (VEDP) was ≤10 mmHg in most subjects. Individual echocardiographic parameters of the diastolic flow and tissue velocities did not correlate with VEDP, other hemodynamics, or post-Fontan clinical course. Incoordinate wall motion in the dominant and in the sizeable secondary ventricle, defined by the lateral wall delay or by the number of dyskinetic segments, was the only echo parameter that correlated, albeit weakly, with VEDP (r = 0.247, P = 0.040), oxygen saturation (r = -0.417, P = 0.001), pulmonary vascular resistance and flow (Qp) (r = -0.303, P = 0.011), Fontan fenestration flow (r = 0.512, P = 0.009), and duration of endotracheal intubation (r = 0.292, P = 0.022). When the nondominant (secondary) ventricle was accounted for in the analysis of incoordinate wall motion, these associations strengthened. The degree of incoordinate ventricular wall motion in diastole was associated with VEDP and postoperative Fontan course in FSV. Analysis of incoordinate wall motion of the dominant and sizeable secondary ventricle may be warranted and should be included in the assessment of the FSV after the Fontan procedure.NEW & NOTEWORTHY Diastolic dysfunction affects outcomes in patients with functionally single ventricles (FSVs) but is difficult to assess. We found that incoordinate wall motion was the only echo parameter that correlated with FSV end-diastolic pressure, oxygen saturation, pulmonary vascular resistance and flow, and duration of endotracheal intubation. Analysis of incoordinate wall motion in the nondominant (secondary) ventricle strengthened these associations. Analyzing incoordinate wall motion should be included in the assessment of the FSV after the Fontan procedure.

Liver Cirrhosis After the Fontan Procedure: Impact of Atrioventricular Valve Failure

BACKGROUND

Liver cirrhosis is now well recognized as a potential complication after the Fontan procedure, although associated risk factors and optimal timing of liver screening remain unclear.

METHODS

All patients who underwent an extracardiac conduit Fontan procedure at The Royal Children's Hospital, Melbourne, were identified using the Australia and New Zealand Fontan Registry. Cirrhosis was diagnosed based on liver biopsy, or a combination of imaging findings and clinical evaluation by a hepatologist.

RESULTS

Between 1997 and 2020, 398 patients underwent an extracardiac conduit Fontan procedure at our center, and 276 had ongoing follow-up in Victoria. Ninety-five patients (34%) underwent liver assessment at a mean age of 18.2 ± 6.7 years (11.8 ± 5.5 years post-Fontan). Fifteen patients (16%) were diagnosed with cirrhosis at a mean age of 22.7 ± 5.9 years (14.0 ± 5.2 years post-Fontan). The need for prior or concomitant atrioventricular valve repair or replacement was associated with an increased risk of cirrhosis (univariable hazard ratio [HR] 7.09, 95% confidence interval [CI] 2.13-23.61, P = .001). By multivariable analysis, factors associated with development of cirrhosis were atrioventricular valve failure prior to Fontan (HR 3.27, 95% CI 1.15-9.31, P = .026) and older age at Fontan operation (HR 1.13 per year increase, 95% CI 1.01-1.26, P = .034). The proportion of patients alive, nontransplanted, and without cirrhosis at 10, 15, and 20 years was 93.4% (95% CI 88.4%-98.7%), 79.6% (95% CI 69.7%-90.8%), and 64.6% (95% CI 51.0%-81.9%), respectively.

CONCLUSIONS

Early commencement of liver screening should be considered for patients with a history of atrioventricular failure during Fontan palliation.

Fontan failure: phenotypes, evaluation, management, and future directions

OBJECTIVES

Management of "failing" and "failed" Fontan circulation, particularly the indications, timing, and type of re-intervention, currently remains nebulous. Factors contributing to pathogenesis and mortality following Fontan procedure differ between children and adults.

METHODS

Since organ systems in individual patients are affected differently, we searched the extant literature for a "failing" and "failed" Fontan reviewing the clinical phenotypes, diagnostic modalities, pharmacological, non-pharmacological, and surgical techniques employed, and their outcomes.

RESULTS

A total of 410 investigations were synthesised. Although proper candidate selection, thoughtful technical modifications, timely deployment of mechanical support devices, tissue-engineered conduits, and Fontan takedown have decreased the peri-operative mortality from 9 to 15% and 1 to 3% per cent in recent series, pernicious changes in organ function are causing long-term patient attrition. In the setting of a failed Fontan circulation, literature documents three surgical options: Fontan revision, Fontan conversion, or cardiac transplantation. The reported morbidity of 25% and mortality of 8-10% among Fontan conversion continue to improve in select institutions. While operative mortality following cardiac transplantation for Fontan failure is 30% higher than for other CHDs, there is no difference in long-term survival with actuarial 10-year survival of around 54%. Mechanical circulatory assistance, stem cells, and tissue-engineered Fontan conduit for destination therapy or as a bridge to transplantation are in infancy for failing Fontan circulation.

CONCLUSIONS

An individualised management strategy according to clinical phenotypes may delay the organ damage in patients with a failing Fontan circulation. At present, cardiac transplantation remains the last stage of palliation with gradually improving outcomes.

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.

Nutritional Management of Patients with Fontan Circulation: A Potential for Improved Outcomes from Birth to Adulthood

Fontan circulation (FC) is a surgically achieved palliation state offered to patients affected by a wide variety of congenital heart defects (CHDs) that are grouped under the name of univentricular heart. The procedure includes three different surgical stages. Malnutrition is a matter of concern in any phase of life for these children, often leading to longer hospital stays, higher mortality rates, and a higher risk of adverse neurodevelopmental and growth outcomes. Notwithstanding the relevance of proper nutrition for this subset of patients, specific guidelines on the matter are lacking. In this review, we aim to analyze the role of an adequate form of nutritional support in patients with FC throughout the different stages of their lives, in order to provide a practical approach to appropriate nutritional management. Firstly, the burden of faltering growth in patients with univentricular heart is analyzed, focusing on the pathogenesis of malnutrition, its detection and evaluation. Secondly, we summarize the nutritional issues of each life phase of a Fontan patient from birth to adulthood. Finally, we highlight the challenges of nutritional management in patients with failing Fontan.

Induction of aggressive arterial and venous dilation therapy in addition to pulmonary dilation therapy (super-Fontan strategy) improves Fontan circulation both at rest and during treadmill exercise

Objective

Methods

Results

Conclusions

Liver nodules after the Fontan operation: role of the computerised tomography scan

Currently, there is an increasing prevalence of liver nodules in patients following the Fontan operation. The appropriate non-invasive modalities have been applied to assess a diagnosis of Fontan-associated liver disease. The aims of this study were to determine the prevalence and associated factors for the presence of liver nodules using CT scan. A cross-sectional study of 34 patients older than 15 years of age was recruited. Ultrasound upper abdomen, ultrasound liver elastography, and CT scan of the upper abdomen were performed after the Fontan operation. The median age of patients was 20 years (range 14-36 years). The median age at the Fontan operation was 7 years (range 5-17 years) and the duration after the Fontan operation was 12 years (range 4-22 years). The prevalence of liver nodules was 62% as detected by CT scans. Hepatic vein pressure in patients with liver nodules was significantly higher than in those without liver nodules. Hepatic vein pressure above 13 mmHg was a factor associated with liver nodules. There was little agreement between the ultrasound of the upper abdomen and CT scan of the upper abdomen in the evaluation of liver nodules. Hepatic pressure was the only associated factor for the occurrence of liver nodules in patients following the Fontan operation. The prevalence of liver nodules was very high after the Fontan operation. The upper abdomen CT scan should be performed for the surveillance of liver nodules in every Fontan patient over the age of 15 years.

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-invasive assessment of liver abnormalities in pediatric Fontan patients

Liver abnormalities are well known among long-term survivors of Fontan palliation, which remains the definite surgery for complex congenital heart disease and single ventricle physiology. Pediatric data however are scarce. We assessed the prevalence and degree of liver abnormalities in pediatric Fontan patients through non-invasive investigations suitable for longitudinal follow-up. Thirty-five patients with a median age of 11.8 years (5.2-16.6) and median time since Fontan of 6 years (1.17-13.83) were studied. Each child underwent a blood test, liver Doppler ultrasound (US), and transient elastography (TE). Healthy children were used as controls for TE measurement. AST, ALT, γGT, and direct bilirubin were abnormal in respectively 12 (34%), 5 (14%), 24 (69%), and 7 (20%) patients, while platelet count was decreased in 7 (20%). Splenomegaly was present in 7 (20%) patients. Portal vein mean flow velocity was < 15 cm/s in 19 (54%) patients indicative of portal hypertension. Twenty-two patients (63%) showed inferior vena cava collapsibility index values below 17%, indicating venous congestion. Hepatic artery and superior mesenteric artery resistance index were inversely correlated with time post Fontan (p < 0.05). TE values in Fontan patients were significantly higher than controls, with a median of 12.6 versus 4.6 kPa (p < 0.001) and were already increased shortly after Fontan completion. Conclusion: Liver abnormalities are frequently observed in pediatric Fontan patients. The non-invasive investigations used were not able to confirm liver fibrosis or differentiate hepatic congestion from fibrosis. Based on our findings, we propose a prospective screening protocol with serial measurements of laboratory, (Doppler) US, and TE parameters. What is Known: • Hepatic dysfunction is a well-known consequence of the Fontan circulation. • The natural history of Fontan-associated liver disease in the pediatric age group remains unclear. What is New: • Liver abnormalities are frequently observed in pediatric Fontan patients; however, differentiating liver fibrosis and hepatic congestion with non-invasive investigations remains challenging. Sonographic Doppler measurements may improve our insight in both Fontan-associated liver disease development and the functioning of the Fontan circulation. • A prospective screening protocol is proposed to improve our ability to detect Fontan-associated liver disease early on and understand its natural history.

Current Treatment Options for the Failing Fontan Circulation

The Fontan operation was introduced in 1968. For congenital malformations, where biventricular repair is unsuitable, the Fontan procedure has provided a long-term palliation strategy with improved outcomes compared to the initially developed procedures. Despite these improvements, several complications merely due to a failing Fontan circulation, including myocardial dysfunction, arrhythmias, increased pulmonary vascular resistance, protein-losing enteropathy, hepatic dysfunction, plastic bronchitis, and thrombo-embolism, may occur, thereby limiting the life-expectancy in this patient cohort. This review provides an overview of the most common complications of Fontan circulation and the currently available treatment options.

Long-term Outcome of Fontan-Associated Protein-Losing Enteropathy: Treatment Modality and Predictive Factor of Mortality

We conducted the first retrospective study on Fontan-associated protein-losing enteropathy (PLE) in Korea. Fontan-associated PLE is still challenging to treat, although the survival rate has improved. There is no best treatment for PLE, and relapse occurs frequently. However, selected patients show promising results after various treatments. It would be helpful to identify the risk factors of mortality in patients with Fontan-associated PLE. High-risk patients should undergo comprehensive evaluations and receive more aggressive therapies for PLE. This study emphasizes the necessity for developing aggressive and individually targeted treatment strategies by sharing our long-term experience on Fontan-associated PLE in the current era.

Background and Objectives

Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE.

Methods

We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea.

Results

PLE occurred in 4.6% of the total 832 patients after the Fontan operation. After a mean period of 7.7 years after Fontan operation, PLE was diagnosed at a mean age of 11.6 years. The mean follow-up period was 8.9 years. The survival rates were 81.6% at 5 years and 76.5% at 10 years. In the multivariate analysis, New York Heart Association Functional classification III or IV (p=0.002), low aortic oxygen saturation (<90%) (p=0.003), and ventricular dysfunction (p=0.032) at the time of PLE diagnosis were found as predictors of mortality. PLE was resolved in 10 of the 38 patients after treatment. Among medical managements, an initial heparin response was associated with survival (p=0.043). Heparin treatment resulted in resolution in 4 patients. We found no evidence on pulmonary vasodilator therapy alone. PLE was also resolved after surgical Fontan fenestration (2/6), aortopulmonary collateral ligation (1/1), and transplantation (1/1).

Conclusions

The survival rate of patients with Fontan-associated PLE has improved with the advancement of conservative care. Although there is no definitive method, some treatments led to the resolution of PLE in one-fourth of the patients. Further investigations are needed to develop the best prevention and therapeutic strategies for PLE.

Heterogeneous outcomes of liver disease after heart transplantation for a failed Fontan procedure

BACKGROUND

Fontan-associated liver disease (FALD) uniformly affects patients with long-term Fontan physiology. The effect of isolated heart transplant (HT) on the course of FALD post-HT is not well understood.

METHODS

We evaluated serial liver imaging pre- and post-HT to assess liver changes over time in a single-center retrospective analysis of Fontan HT recipients who had pre- and ≥1-year post-HT liver imaging. Available patient demographic and clinical data were reviewed, including available liver biopsy results.

RESULTS

Serial liver imaging was available in 19 patients with a median age at HT of 12 years (range 3-23), the median age from Fontan to HT of 5.7 years (range 0.8-16), and the median time from imaging to follow up of 27 months (range 12-136 months). Pre-HT liver imaging was classified as follows: normal (n=1), congested (n=9), fibrotic (n=7), and cirrhotic (n=2). The majority of transplanted patients (15/19) had improvement in their post-HT liver imaging, including 13 patients with initially abnormal imaging pre-HT having normal liver imaging at follow-up. One patient had persistent cirrhosis at 26-month follow-up, one patient had unchanged fibrosis at 18-month follow-up, and one patient progressed from fibrosis pre-HT to cirrhosis post-HT at 136 months. No patients had overt isolated liver failure during pre- or post-HT follow-up. Liver biopsy did not consistently correlate with imaging findings.

CONCLUSIONS

Post-HT liver imaging evaluation in Fontan patients reveals heterogeneous liver outcomes. These results not only provide evidence for the improvement of FALD post-HT but also show the need for serial liver imaging follow-up post-HT.

Impact of Atrial Fibrillation on Fontan Circulation: Fontan Computational Model

BACKGROUND

Patients with Fontan circulation may develop heart failure resulting in atrial fibrillation during the late phase. Inotropic effects to ameliorate hemodynamics on the Fontan circulation are not well understood, especially when in atrial fibrillation. This study was performed to determine whether dobutamine therapy in patients with Fontan circulation has limited effects on improving hemodynamics.

METHODS

Lumped computational models (sinus and atrial fibrillation) were employed including biventricular, atriopulmonary connection (APC), and extracardiac total cavopulmonary connection (TCPC) Fontan models. The condition of atrial fibrillation including lack of atrial beat, irregular ventricular contraction, and time-varying elastance for the ventricle was introduced. A different dose of dobutamine was given by varying the elastance of the ventricle, heart rate, and peripheral resistance.

RESULTS

In all models, the cardiac output decreased by 22.5% to 25.8% in atrial fibrillation. At 10 μg/kg/min of dobutamine in sinus rhythm, the cardiac output increased by 32.3% in the biventricular model but by only 9.2% (p<0.001) and 9.1% (p<0.001) in the APC and TCPC Fontan models, respectively. At 10 μg/kg/min of dobutamine in atrial fibrillation, the percent increase in the cardiac output in the Fontan circulation [11.8% increase in APC (p<0.001) and 11.9% increase in TCPC (p<0.001)] was significantly less than that in the biventricular circulation (32.3% increase).

CONCLUSIONS

In the Fontan circulation, atrial fibrillation itself reduced the cardiac output by approximately 25%, and dobutamine had a limited effect on increasing the cardiac output, especially when in atrial fibrillation. Maintaining sinus rhythm in patients with Fontan circulation is very important.

Reaching consensus for unified medical language in Fontan care

Aims

The Fontan operation has resulted in improved survival in patients with single‐ventricle congenital heart disease. As a result, there is a growing population of teenagers and adults with a Fontan circulation. Many co‐morbidities have been increasingly recognized in this population due to the unique features of the Fontan circulation. Standardization of how Fontan co‐morbid conditions are defined will help facilitate understanding, consistency and interpretability of research and clinical experience. Unifying common language usage in Fontan is a critical precursor step for data comparison of research findings and clinical outcomes and ultimately accelerating improvements in management for this growing group of patients. This manuscript aimed to create unified definitions for morbidities seen after the Fontan palliation.

Methods

In association of many congenital heart disease organizations, this work used Delphi methodology to reach a broad consensus among recognized experts regarding commonly used terms in Fontan care and research. Each definition underwent at least three rounds of revisions to reach a final definition through surveys sent to experts in the field of single‐ventricle care.

Results

The process of reaching a consensus on multiple morbidities associated with the Fontan procedure is summarized in this manuscript. The different versions that preceded reaching the consensus are also presented in the Supporting Information. Table 1 represents the final definitions according to the consensus.

Conclusions

We propose the use of these definitions for clinical care, future research studies, registry development and clinical trials.

Status of Multidisciplinary Collaboration in Neonatal Cardiac Care in the United States

While outcomes for neonates with congenital heart disease have improved, it is apparent that substantial variability exists among centers with regard to the multidisciplinary approach to care for this medically fragile patient population. We endeavored to understand the landscape of neonatal cardiac care in the United States. A survey was distributed to physicians who provide neonatal cardiac care in the United States regarding (1) collaborative efforts in care of neonates with congenital heart disease (CHD); (2) access to neonatal cardiac training; and (3) barriers to the implementation of protocols for neonatal cardiac care. Responses were collected from 10/2018 to 6/2019. We received responses from 172 of 608 physicians (28% response rate) from 89 centers. When compared to responses received from physicians at low-volume centers (< 300 annual bypass cases), those at high-volume centers reported more involvement from the neurodevelopmental teams (58% vs. 29%; P = 0.012) and a standardized transition to outpatient care (68% vs. 52%; P = 0.038). While a majority of cardiothoracic surgery and anesthesiology respondents reported multidisciplinary involvement, less than half of cardiology and neonatology supported this statement. The most commonly reported obstacles to multidisciplinary engagement were culture (61.6%) and logistics (47.1%). Having a standardized neonatal cardiac curriculum for neonatal fellows was positively associated with the perception that multidisciplinary collaboration was "always" in place (53% vs. 40%; P = 0.09). There is considerable variation among centers in regard to personnel involved in neonatal cardiac care, related education, and perceived multidisciplinary collaboration among team members. The survey findings suggest the need to establish concrete standards for neonatal cardiac surgical programs, with ongoing quality improvement processes.

Functional lymphatic reserve capacity is depressed in patients with a Fontan circulation

Background

Lymphatic abnormalities play a role in effusions in individuals with a Fontan circulation. Recent results using near‐infrared fluorescence imaging disclosed an increased contraction frequency of lymphatic vessels in Fontan patients compared to healthy controls. It is proposed that the elevated lymphatic pumping seen in the Fontan patients is necessary to maintain habitual interstitial fluid balance. Hyperthermia has previously been used as a tool for lymphatic stress test. By increasing fluid filtration in the capillary bed, the lymphatic workload and contraction frequency are increased accordingly. Using near‐infrared fluorescence imaging, the lymphatic functional reserve capacity in Fontan patients were explored with a lymphatic stress test.

Methods

Fontan patients (n = 33) were compared to a group of 15 healthy individuals of equal age, weight, and gender. The function of the superficial lymphatic vessels in the lower leg during rest and after inducing hyperthermia was investigated, using near‐infrared fluorescence imaging.

Results

Baseline values in the Fontan patients showed a 57% higher contraction frequency compared to the healthy controls (0.4 ± 0.3 min⁻¹ vs. 0.3 ± 0.2 min⁻¹, p = 0.0445). After inducing stress on the lymphatic vessels with hyperthermia the ability to increase contraction frequency was decreased in the Fontan patients compared to the controls (0.6 ± 0.5 min⁻¹ vs. 1.2 ± 0.8 min⁻¹, p = 0.0102).

Conclusions

Fontan patients had a higher lymphatic contraction frequency during normal circumstances. In the Fontan patients, the hyperthermia response is dampened indicating that the functional lymphatic reserve capacity is depressed. This diminished reserve capacity could be part of the explanation as to why some Fontan patients develop late‐onset lymphatic complications.

Analysis of the 2020 European Society of Cardiology (ESC) Guidelines for the Management of Adults With Congenital Heart Disease (ACHD)

Adult congenital heart disease (ACHD) continues to rapidly increase worldwide. With an estimated 1.5 million adults with ACHD in the USA alone, there is a growing need for better education in the management of these complex patients and multiple knowledge gaps exist. This manuscript comprehensively reviewed the recent (2020) updated European Society of Cardiology Guidelines for the management of ACHD created by the Task Force for the management of adult congenital heart disease of the European Society of Cardiology, with perioperative implications for the adult cardiac anesthesiologist and intensivist who may be called upon to manage these complex patients.

Hepatorenal dysfunction assessment with the Model for End-Stage Liver Disease Excluding INR score predicts worse survival after heart transplant in pediatric Fontan patients

BACKGROUND

Fontan physiology results in multiorgan dysfunction, most notably affecting the liver and kidney. We evaluated the utility of Model for End-Stage Liver Disease Excluding INR (MELD-XI) score, a score evaluating the function of both liver and kidney to identify Fontan patients at increased risk for morbidity and mortality post-heart transplant.

METHODS

The Pediatric Heart Transplant Society database was queried to identify Fontan patients listed for heart transplant between January 2005 and December 2018. MELD-XI scores were calculated at listing and heart transplant. A multivariable analysis was conducted to identify risk factors for post-heart transplant mortality. Demographic, clinical characteristics, and survival differences were evaluated and compared between the high and low MELD-XI score cohorts. The impact of changing MELD-XI scores during the waitlist period on post-heart transplant outcomes was also evaluated.

RESULTS

Of 565 Fontan patients who underwent transplantation, 524 (93%) had calculable MELD-XI scores at the time of heart transplant: 421 calculable at listing and 392 calculable at listing and at heart transplant. On multivariable analysis, only MELD-XI score (squared) (hazard ratio, 1.007), history of protein-losing enteropathy (hazard ratio, 2.1), and ventricular assist device use at transplant (hazard ratio, 3.4) were risk factors for early phase post-heart transplant mortality. Patients with high MELD-XI scores at heart transplant had inferior survival post-heart transplant (P = .02); those in the high MELD-XI score cohort at wait listing and heart transplant tend to have the worst post-heart transplant survival; however, this was not significant (P = .42).

CONCLUSIONS

The MELD-XI, an easily calculated score, serves as a valuable aid in identifying pediatric Fontan patients at increased risk for post-heart transplant mortality.

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.

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: pathophysiology, investigations, predictors of severity and management

Cardiac hepatopathy is the liver injury resulting from congestion and ischaemia associated with acute or chronic heart failure. The improved longevity of adults with operated congenital heart disease who develop heart failure as an increasingly late event makes this form of liver injury increasingly clinically relevant. Patients with congenital heart disease with a single ventricle anomaly, who require creation of a Fontan circulation, are particularly vulnerable as they have elevated venous filling pressures with chronic liver congestion. Progression to liver fibrosis and eventually cirrhosis may occur, with its associated risks of liver failure and hepatocellular carcinoma. This risk likely increases over the patient's lifetime, related to the duration post-surgical repair and reflects the chronicity of congestion. Liver biopsy is rarely performed due to a higher risk of complications in the setting of elevated venous pressures, and the frequent use of anticoagulation. Non-invasive methods of liver assessment are poorly validated and different factors require consideration compared to other chronic liver diseases. This review discusses the current understanding of cardiac hepatopathy in congenital heart disease patients with a Fontan circulation. This entity has recently been called Fontan Associated Liver Disease in the literature, with the term useful in recognising that the pathophysiology is incompletely understood, and that long-standing venous pressure elevation and hypoxaemia are presumed to play an additional significant role in the pathogenesis of the liver injury.

The Adult Patient with a Fontan

The authors summarize the most important anatomic and physiologic substrates of Fontan circulation. Common anatomic substrates include hypoplastic left heart syndrome, tricuspid atresia, double inlet left ventricle, and unbalanced atrioventricular septal defects. After the Fontan operation exercise capacity is limited and the key hemodynamic drivers is limited preload due to a relatively fixed pulmonary vascular resistance. The authors provide contemporary data on survival, morbidity, and need for reintervention. Operative morality is now expected to be less than 1% and 30 year survival approximately 89%. The authors delineate potential therapeutic approaches for the potential late complications.

Treatment strategies for protein-losing enteropathy in Fontan-palliated patients

OBJECTIVE

Protein-losing enteropathy is an infrequent but severe condition occurring after Fontan procedure. The multifactorial pathogenesis remains unclear and no single proposed treatment strategy has proven universally successful. Therefore, we sought to describe different treatment strategies and their effect on clinical outcome and mortality.

MATERIAL AND METHODS

We performed a retrospective observational study. From the total cohort of 439 Fontan patients treated in our institution during the study period 1986-2019, 30 patients (6.8%) with protein-losing enteropathy were identified. Perioperative, clinical, echocardiographic, laboratory, and invasive haemodynamic findings and treatment details were analysed.

RESULTS

Median follow-up after disease onset was 13.1 years [interquartile range 10.6]. Twenty-five patients received surgical or interventional treatment for haemodynamic restrictions. Medical treatment, predominantly pulmonary vasodilator and/or systemic anti-inflammatory therapy with budesonide, was initiated in 28 patients. In 15 patients, a stable remission could be achieved by medical or surgical procedures (n = 3 each), by combined multimodal therapy (n = 8), or ultimately by cardiac transplantation (n = 1). Phrenic palsy, bradyarrhythmia, Fontan pathway stenosis, and absence of a fenestration were significantly associated with development of protein-losing enteropathy (p = 0.001-0.48). Ten patients (33.3%) died during follow-up; 5-year survival estimate was 96.1%. In unadjusted analysis, medical therapy with budesonide and pulmonary vasodilator therapy in combination was associated with improved survival.

CONCLUSIONS

Protein-losing enteropathy is a serious condition limiting survival after the Fontan procedure. Comprehensive assessment and individual treatment strategies are mandatory to achieve best possible outcome. Nevertheless, relapse is frequent and long-term mortality substantial. Cardiac transplantation should be considered early as treatment option.

Targeted metabolomic analysis of serum phospholipid and acylcarnitine in the adult Fontan patient with a dominant left ventricle

BACKGROUND

Patients with a Fontan circulation have altered cholesterol and lipoprotein values. We analysed small organic molecules in extended phopsholipid and acylcarnitine metabolic pathways ('metabolomes') in adult Fontan patients with a dominant left ventricle, seeking differences between profiles in baseline and Fontan circulations.

METHODS

In an observational matched cross-sectional study, we compared phosphatidylcholine (PC), sphingomyelin (SM), and acylcarnitine metabolomes (105 analytes; AbsoluteIDQ® p180 kit (Biocrates Life Sciences AG, Innsbruck, Austria) in 20 adult Fontan patients having a dominant left ventricle with those in 20 age- and sex-matched healthy controls.

RESULTS

Serum levels of total PC (q-value 0.01), total SM (q-value 0.0002) were significantly lower, and total acylcarnitines (q-value 0.02) were significantly higher in patients than in controls. After normalisation of data, serum levels of 12 PC and 1 SM Fontan patients were significantly lower (q-values <0.05), and concentrations of 3 acylcarnitines were significantly higher than those in controls (q-values <0.05).

CONCLUSION

Metabolomic profiling can use small specimens to identify biomarker patterns that track derangement in multiple metabolic pathways. The striking alterations in the phospholipid and acylcarnitine metabolome that we found in Fontan patients may reflect altered cell signalling and metabolism as found in heart failure in biventricular patients, chronic low-level inflammation, and alteration of functional or structural properties of lymphatic or blood vessels.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier NCT03886935.

Severity of Fontan-Associated Liver Disease Correlates with Fontan Hemodynamics

Fontan-palliated patients are at risk for the development of Fontan-associated liver disease (FALD). In this study, we performed a detailed hemodynamic and hepatic assessment to analyze the incidence and spectrum of FALD and its association with patients' hemodynamics. From 2017 to 2019, 145 patients underwent a detailed, age-adjusted hepatic examination including laboratory analysis (FibroTest^®, n = 101), liver ultrasound (n = 117) and transient elastography (FibroScan^®, n = 61). The median patient age was 16.0 years [IQR 14.2], and the median duration of the Fontan circulation was 10.3 years [IQR 14.7]. Hemodynamic assessment was performed using echocardiography, cardiopulmonary exercise capacity testing and cardiac catheterization. Liver ultrasound revealed hepatic parenchymal changes in 83 patients (70.9%). Severe liver cirrhosis was detectable in 20 patients (17.1%). Median liver stiffness measured by FibroScan^® was 27.7 kPa [IQR 14.5], and the median Fibrotest^® score was 0.5 [IQR 0.3], corresponding to fibrosis stage ≥ 2. Liver stiffness values and Fibrotest^® scores correlated significantly with Fontan duration (P₁ = 0.013, P₂ = 0.012). Exercise performance was significantly impaired in patients with severe liver cirrhosis (P = 0.003). Pulmonary artery pressure and end-diastolic pressure were highly elevated in cirrhotic patients (P₁ = 0.008, P₂ = 0.003). Multivariable risk factor analysis revealed Fontan duration to be a major risk factor for the development of FALD (P < 0.001, OR 0.77, CI 0.68-0.87). In the majority of patients, hepatic abnormalities suggestive of FALD were detectable by liver ultrasound, transient elastography and laboratory analysis. The severity of FALD correlated significantly with Fontan duration and impaired Fontan hemodynamics. A detailed hepatic assessment is indispensable for long-term surveillance of Fontan patients.

CT and MR imaging findings of the livers in adults with Fontan palliation: an observational study

PURPOSE

To describe liver imaging findings and complications on computed tomography (CT) or magnetic resonance imaging (MRI) in adults with Fontan palliation and investigate whether imaging features show correlations with clinical and physiological parameters.

METHODS

Our Institutional Review Board approved this retrospective study. Two blinded abdominal radiologists reviewed abdominal CT (n = 21) and MRI (n = 16) images between September 2011 and October 2017 in 37 adults (median age 27 years, interquartile range 21-36 years, 14 males [38%]) with a Fontan palliation (median post-Fontan duration 22 years, interquartile range 19-28 years). Correlation between CT/MRI findings and clinical parameters including laboratory results within 6 months of CT/MRI examinations was assessed by Spearman's rank correlation coefficient.

RESULTS

Lobulated hepatic surface and blunt hepatic edge were seen in 92% (34/37) and 95% (35/37) of patients, respectively. Surface nodularity was noted in 32% (12/37). In 7 patients, there were 11 hepatic nodules which showed arterial-phase hyperenhancement and washout. Among them, 2 were biopsy-proven hepatocellular carcinomas (HCCs), and the remaining 9 were focal nodular hyperplasia (FNH)-like nodules. Suprahepatic inferior vena cava (IVC) diameter showed positive correlations with post-Fontan duration (p < 0.01), serum gamma-glutamyl transferase (p < 0.01), and total bilirubin (p < 0.01).

CONCLUSION

The livers in post-Fontan adults show a unique morphology of blunt edge and lobulating surface with occasional nodularity. There is a diagnostic challenge in distinguishing HCCs from FNH-like nodules in post-Fontan population due to overlapping imaging findings. Suprahepatic IVC diameter is a potentially useful imaging marker that reflects hepatic dysfunction in Fontan palliation.

Relation of Magnetic Resonance Elastography to Fontan Failure and Portal Hypertension

Fontan associated liver disease is associated with morbidity and mortality in palliated single-ventricle congenital heart disease patients. Magnetic resonance elastography (MRE) provides a quantitative assessment of liver stiffness in Fontan patients. We hypothesized that MRE liver stiffness correlates with liver enzymes, hemodynamics, portal hypertension, and Fontan failure (FF). All adult Fontan patients who had MRE between 2011 and 2018 were included. Radiologic portal hypertension was defined as splenomegaly, ascites, and/or varices. FF was defined as death, transplantation, or heart failure symptoms requiring escalation of diuretics. Seventy patients with a median age of 24.7 years and a median follow-up from MRE of 3.9 years were included. The median liver stiffness was 4.3 kPa (interquartile range [IQR]: 3.8 to 5.0 kPa). There was a weak, positive correlation between liver stiffness and Fontan pathway pressure (r = 0.34, p = 0.03). There was a moderate negative correlation of liver stiffness with ventricular ejection fraction (r = -0.52, p = 0.03). Liver stiffness was weakly positively correlated with liver transaminases and gamma glutamyl transferase. Patients with portal hypertension had higher liver stiffness compared to patients without (5.2 ± 1.3 vs 4.2 ± 0.8 kPa, p = 0.03). At MRE or during follow-up, 13 patients (19%) met definition of FF and had significantly higher liver stiffness compared to patients without FF (5.1 [IQR: 4.3 to 6.3] vs 4.2 [IQR: 3.7 to 4.7] kPa, p = 0.01). Liver stiffness above 4.5 kPa differentiated FF with a sensitivity of 77% and specificity of 77%. In conclusion, elevated MRE-derived liver stiffness is associated with worse hemodynamics, liver enzymes and clinical outcomes in Fontan patients. This measure may serve as a global imaging biomarker of Fontan health.

Emerging clinical applications of strain imaging and three-dimensional echocardiography for the assessment of ventricular function in adult congenital heart disease

Management of congenital heart disease (CHD) in adults (ACHD) remains an ongoing challenge due to the presence of residual hemodynamic lesions and development of ventricular dysfunction in a large number of patients. Echocardiographic imaging plays a central role in clinical decision-making and selection of patients who will benefit most from catheter interventions or cardiac surgery.. Recent advances in both strain imaging and three-dimensional (3D)-echocardiography have significantly contributed to a greater understanding of the complex pathophysiological mechanisms involved in CHD. The aim of this paper is to provide an overview of emerging clinical applications of speckle-tracking imaging and 3D-echocardiography in ACHD with focus on functional assessment, ventriculo-ventricular interdependency, mechanisms of electromechanical delay, and twist abnormalities in adults with tetralogy of Fallot (TOF), a systemic RV after atrial switch repair or in double discordance ventricles, and in those with a Fontan circulation.

Initiating a Fontan multidisciplinary clinic: Decreasing care variability, improving surveillance, and subsequent treatment of Fontan survivors

BACKGROUND

Children with single ventricle (SV) heart disease who undergo Fontan operation are at risk for developing multiorgan dysfunction. Although survival has improved, significant comorbidities involving multiple organ systems may develop, requiring evaluation and management by many subspecialists. Using data from an internal survey, we documented high care variability for our Fontan population. We then developed a multidisciplinary clinic, designed and implemented a clinical care pathway to decrease variability of patient assessment.

METHODS

After creating a multidisciplinary team and a clinical care pathway, we initiated a multidisciplinary clinic (MDC) where patients could see multiple subspecialists during a single encounter. We then monitored our effectiveness by retrospective chart review to determine care pathway adherence (process measure) and incidence of new diagnoses of end-organ injury (outcome measure) as well interventions implemented. Adherence was analyzed using statistical process control (SPC) charts.

RESULTS

Eighty-six patients were seen in the MDC from January 2016 to September 2017. The proportion of patients with appropriate testing increased, related to strong care pathway adherence. A significant amount of novel pathology was diagnosed in all evaluated organ systems, both Fontan-associated comorbidities and general pediatric diagnoses. Subsequent interventions included cardiac catheterization n = 21 (31%) with more than half of these patients undergoing intervention n = 17 (20%), and liver biopsy n = 9 (10%). Additionally, 58 patients (67%) were referred to a neuropsychologist based on perceived clinical need, with n = 34 (40%) undergoing a neuropsychological evaluation.

CONCLUSIONS

Children who have undergone Fontan palliation are at risk for developing cardiac and noncardiac comorbidities. Use and adherence to an institutional care pathway resulted in the diagnosis of significant novel pathology and subsequently provided opportunity for intervention.

Thyroid Function in Patients With a Fontan Circulation

In this study, we tested our hypothesis that thyroid function is impaired and contributes to perturbed hemodynamics in patients after Fontan operation. Cardiac catheterization and blood tests for thyroid function were performed in 37 patients who underwent a Fontan operation. Among them, 12 patients (33%) had subclinical thyroid dysfunction with an elevated thyroid-stimulating hormone level despite normal thyroxine levels. Thyroid-stimulating hormone levels were significantly correlated with central venous pressure (p <0.01, R² = 0.3), and patients with subclinical hypothyroidism showed significantly elevated γ-glutamyltransferase level, an indicator of liver congestion, compared with the other patients (125.6 ± 12.2 vs 67.6 ± 4.6 IU/L, p <0.01). In addition, the levels of free triiodothyronine, an effective thyroid hormone, were significantly lower in patients with subclinical hypothyroidism than in those with normal thyroid function (3.1 ± 0.1 vs 3.5 ± 0.1 pg/dl, p <0.01). The free triiodothyronine level was significantly and negatively correlated with the relaxation time constant (p = 0.03) and brain natriuretic hormone (p <0.01) level and positively correlated with the cardiac index (p = 0.04). In conclusion, venous congestion in Fontan patients may cause thyroid dysfunction, which can be responsible for decreased ventricular function and cardiac output in Fontan patients. Thus, thyroid function should be routinely monitored after Fontan surgery.

Impact of the Fontan Operation on Organ Systems

In patients having undergone the Fontan operation, besides the well discussed changes in the cardiac, pulmonary and gastrointestinal system, alterations of further organ systems including the hematologic, immunologic, endocrinological and metabolic are reported. As a medical adjunct to Fontan surgery, the systematic study of the central role of the liver as a metabolizing and synthesizing organ should allow for a better understanding of the pathomechanism underlying the typical problems in Fontan patients, and in this context, the profiling of endocrinological and metabolic patterns might offer a tool for the optimization of Fontan follow-up, targeted monitoring and specific adjunct treatment.

Fifty-Five Years Follow-Up of 111 Adult Survivors After Biventricular Repair of PAIVS and PS

There is paucity of long-term data on adult survivors after biventricular repair of pulmonary atresia with intact ventricular septum (PAIVS) and pulmonary stenosis (PS). This study aimed to determine the cardiac and non-cardiac outcomes of adult survivors after biventricular repair of PAIVS and PS. The cardiac, neurodevelopmental and liver problems of 111 adults, 40 with PAIVS and 71 with PS, were reviewed. The median follow-up duration of our patients was 26.5 years (range 14.8-55 years). The freedom from reintervention at 30 years was 17.4% and 73.3% for PAIVS and PS patients (p < 0.001), respectively. Compared with PS patients, PAIVS patients had significantly greater prevalence of right atrial and right ventricular (RV) dilatation, and moderate to severe tricuspid and pulmonary regurgitation (all p < 0.05), and cardiac arrhythmias (22.5% vs. 8.5%, p = 0.047). The freedom from development of cardiac arrhythmias at 30 years of 68.4% and 91.6%, respectively, in PAIVS and PS patients (p = 0.03). Cox proportional hazards model identified PAIVS as an independent risk factor for reintervention (HR 4.0, 95% CI 2.1-7.6, p < 0.001) and development of arrhythmias (HR 4.1, 95% CI 1.1-14.4, p = 0.03). Neurodevelopmental problems were found in 17.5% of PAIVS patients and 7.0% of PS patients (p = 0.11). Liver problems occurred in 2 (5%) PAIVS patients, both of whom required conversion to 1.5 ventricular repair. In conclusion, long-term problems, including the need for reinterventions, cardiac arrhythmias, RV dilation, pulmonary regurgitation, and neurodevelopmental and liver issues are more prevalent in adult PAIVS than PS survivors.

Surveillance Testing and Preventive Care After Fontan Operation: A Multi-Institutional Survey

More children with single ventricle heart disease are surviving after Fontan surgery. This circulation has pervasive effects on multiple organ systems and has unique modes of failure. Many centers have created multidisciplinary programs to care for these patients. Our aim was to survey such programs to better understand current approaches to care. We hypothesized that significant variability in surveillance testing strategy would be present. Eleven academic institutions with established Fontan care programs performing a combined estimated 300 Fontan surgeries per year, with a total population of 1500-2000 Fontan patients, were surveyed using a REDCap survey regarding surveillance testing and basic practice philosophies. Fontan care programs were structured both as consultative services (64%) and as the primary clinical team (9%). Electrocardiograms (73%) and echocardiograms (64%) were most commonly obtained annually. Serum studies, including complete blood count (73%), complete metabolic panel (73%), and Brain-type natriuretic peptide (54%), were most commonly obtained annually. Hepatic testing consisted of liver ultrasound in most centers, obtained biennially (45%) or > every 2 years (45%). Liver biopsy was not routinely recommended (54%). Neurodevelopmental outcomes were assessed at most institutions (54%), with a median frequency of every 3-4 years. There is considerable variability in the surveillance testing regimen and management strategy after a Fontan procedure at surveyed programs. There is an urgent need for surveillance guidelines to reduce variability, define quality metrics, streamline collaborative practice, and prospective research to better understand the complex adaptations of the body to Fontan physiology.

Fontan-associated protein-losing enteropathy and post‒heart transplant outcomes: A multicenter study

BACKGROUND

The influence of Fontan-associated protein-losing enteropathy's (PLE) severity, duration, and treatment on heart transplant (HTx) outcomes is unknown. We hypothesized that long-standing PLE and PLE requiring more intensive therapy are associated with increased post-HTx mortality.

METHODS

This 12-center, retrospective cohort study of post-Fontan patients with PLE referred for HTx from 2003 to 2015 involved collection of demographic, medical, surgical, and catheterization data, as well as PLE-specific data, including duration of disease, intensity/details of treatment, hospitalizations, and complications. Factors associated with waitlist and post-HTx outcomes and PLE resolution were sought.

RESULTS

Eighty patients (median of 5 per center) were referred for HTx evaluation. Of 68 patients listed for HTx, 8 were removed due to deterioration, 4 died waiting, and 4 remain listed. In 52 patients undergoing HTx, post-HTx 1-month survival was 92% and 1-year survival was 83%. PLE-specific factors, including duration of PLE pre-HTx, pre-HTx hospitalizations, need for/frequency of albumin replacement, PLE therapies, and growth parameters had no association with post-HTx mortality. Immunosuppressant regimen was associated with mortality; standard mycophenolate mofetil immunotherapy was used in 95% of survivors compared with only 44% of non-survivors (p = 0.03). Rejection (53%) and infection (42%) post-HTx were common, but not associated with PLE-specific factors. PLE resolved completely in all but 1 HTx survivor at a median of 1 month (interquartile range 1 to 3 months); resolution was not affected by PLE-specific factors.

CONCLUSIONS

PLE severity, duration, and treatment do not influence post-HTx outcome, but immunosuppressive regimen may have an impact on survival. PLE resolves in nearly all survivors.

Pulmonary Screening in Subjects after the Fontan Procedure

OBJECTIVES

To review the pulmonary findings of the first 51 patients who presented to our interdisciplinary single-ventricle clinic after undergoing the Fontan procedure.

STUDY DESIGN

We performed an Institutional Review Board-approved retrospective review of 51 patients evaluated following the Fontan procedure. Evaluation included history, physical examination, pulmonary function testing, and 6-minute walk. Descriptive statistics were used to describe the population and testing data.

RESULTS

Sixty-one percent of the patients had a pulmonary concern raised during the visit. Three patients had plastic bronchitis. Abnormal lung function testing was present in 46% of patients. Two-thirds (66%) of the patients had significant desaturation during the 6-minute walk test. Patients who underwent a fenestrated Fontan procedure and those who underwent unfenestrated Fontan were compared in terms of saturation and 6-minute walk test results. Sleep concerns were present in 45% of the patients.

CONCLUSIONS

Pulmonary morbidities are common in patients after Fontan surgery and include plastic bronchitis, abnormal lung function, desaturations with walking, and sleep concerns. Abnormal lung function and obstructive sleep apnea may stress the Fontan circuit and may have implications for cognitive and emotional functioning. A pulmonologist involved in the care of patients after Fontan surgery can assist in screening for comorbidities and recommend interventions.

Fontan Surgical Planning: Previous Accomplishments, Current Challenges, and Future Directions

The ultimate goal of Fontan surgical planning is to provide additional insights into the clinical decision-making process. In its current state, surgical planning offers an accurate hemodynamic assessment of the pre-operative condition, provides anatomical constraints for potential surgical options, and produces decent post-operative predictions if boundary conditions are similar enough between the pre-operative and post-operative states. Moving forward, validation with post-operative data is a necessary step in order to assess the accuracy of surgical planning and determine which methodological improvements are needed. Future efforts to automate the surgical planning process will reduce the individual expertise needed and encourage use in the clinic by clinicians. As post-operative physiologic predictions improve, Fontan surgical planning will become an more effective tool to accurately model patient-specific hemodynamics.

Toward a patient-specific tissue engineered vascular graft

Integrating three-dimensional printing with the creation of tissue-engineered vascular grafts could provide a readily available, patient-specific, autologous tissue source that could significantly improve outcomes in newborns with congenital heart disease. Here, we present the recent case of a candidate for our tissue-engineered vascular graft clinical trial deemed ineligible due to complex anatomical requirements and consider the application of three-dimensional printing technologies for a patient-specific graft. We 3D-printed a closed-disposable seeding device and validated that it performed equivalently to the traditional open seeding technique using ovine bone marrow–derived mononuclear cells. Next, our candidate’s preoperative imaging was reviewed to propose a patient-specific graft. A seeding apparatus was then designed to accommodate the custom graft and 3D-printed on a commodity fused deposition modeler. This exploratory feasibility study represents an important proof of concept advancing progress toward a rationally designed patient-specific tissue-engineered vascular graft for clinical application.

Acoustic radiation force impulse of the liver after Fontan operation: Correlation with cardiopulmonary exercise test

BACKGROUND

The current management paradigm for children with single ventricle heart disease involves a series of palliative surgeries, culminating in the Fontan operation. This physiology results in a high central venous pressure, and in the setting of single ventricle heart disease, results in hepatic injury and fibrosis over time. Fontan-associated liver disease (FALD) is universally present in this cohort, and the current gold standard for diagnosis remains biopsy. Noninvasive assessments of liver fibrosis, such as ultrasound with elastography or acoustic radiation force impulse (ARFI), has been utilized in this cohort. The effect of poor cardiovascular efficiency, as measured by cardiopulmonary exercise test (CPET), on assessments of liver fibrosis remains poorly understood.

METHODS

Retrospective, cross-sectional study. Subjects were evaluated in a multidisciplinary clinic setting for patients who have undergone Fontan operation. CPETs, liver ultrasound with elastography (ARFI), and standard laboratory tests were performed as part of routine clinical care pathway. Statistical analysis included linear correlation.

RESULTS

There was a poor correlation between mean ARFI velocity and peak oxygen consumption (VO_2max ) in this cohort (r = .20, P = NS). Similarly, there was poor correlation between ARFI and biomarkers of liver injury, time since Fontan operation and Fontan pressure.

DISCUSSION

ARFI had poor correlation with functional capacity after Fontan, as measured by VO_2max obtained during CPET. While a single measurement of liver elastography was not associated with cardiopulmonary efficiency, longitudinal data may reveal an association.