Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

Discordances in Kinetic Energy Between the Superior Cavopulmonary Connection and Single Ventricle Are Associated With Suboptimal Fontan Outcomes: A Pre-Fontan 4-Dimensional Flow Study

BACKGROUND

Patients with functional single ventricle (SV) are at risk for adverse outcomes after staged palliation from the superior cavopulmonary connection (SCPC) to the Fontan. Current pre-Fontan assessment by cardiac magnetic resonance and cardiac catheterization includes measuring atrioventricular valve regurgitation, aortopulmonary collateral burden, and pressures. Four-dimensional flow can quantify complex flows representing hemodynamic inefficiency. This study determined the clinical significance of kinetic energy (KE) and viscous energy loss in patients before the Fontan procedure using 4-dimensional flow.

METHODS AND RESULTS

This was a retrospective analysis of patients before the Fontan procedure who underwent ferumoxytol-enhanced cardiac magnetic resonance and same-day catheterization. Four-dimensional flow data sets were analyzed using ITFlow (CardioFlowDesign) to measure KE/viscous energy loss in the atrium, SV, and SCPC. A composite outcome was defined by rejected Fontan candidacy, prolonged hospitalization, lymphatic dysfunction, or heart failure. The relationship between these outcomes and KE/viscous energy loss was assessed by bivariable and multivariable logistic regression analyses as appropriate. Sixty-five patients (3.9±1.5 years, 0.64±0.1 m2) were included. Fifty (77%) proceeded to Fontan operation with median hospitalization time of 8.5 (interquartile range, 7-12.7) days. Twenty-six (40%) experienced a composite outcome, including 9 with rejected candidacy. Lower SCPC flow was associated with an outcome (P=0.042). Meanwhile, higher SV KE and lower SCPC KE were independently associated with composite outcome (odds ratio, 3.63 [95% CI, 1.32-13.2]; P=0.0263; odds ratio, 0.906 [95% CI, 0.814-0.980]; P=0.0377). Higher SV KE and lower SCPC KE corresponded to significant atrioventricular valve regurgitation, higher aortopulmonary collateral burden, and higher cathetherization pressures.

CONCLUSIONS

Four-dimensional flow analysis provides insight into SV hemodynamics and is associated with short-term outcomes. Future work will analyze the longitudinal implications for patients undergoing the Fontan procedure.

Serial Exercise Testing in Children With Known or Suspected Congenital and Acquired Heart Disease: A Narrative Review and Survey of Current Practice

BACKGROUND

Exercise parameters can be altered in children with congenital heart disease or acquired heart disease compared with children with normal hearts. Exercise testing has proven a useful tool to predict patient outcomes and even the need for reintervention in several cardiovascular disease processes. There are established guidelines for serial exercise stress testing in adults with congenital heart disease, but corollary guidelines do not exist for the pediatric population.

METHODS AND RESULTS

A narrative literature review was completed. Evidence was ranked by a 4-point scale as outlined by the American College of Sports Medicine evidence categories. A survey was sent to experts in pediatric exercise physiology across the country regarding their current testing practices for 26 unique congenital heart disease or known or suspected acquired heart disease lesions. Survey questions were related to the frequency of testing, the age at which exercise testing is started, and if the frequency of testing is altered by a patient presenting with symptoms. Our literature search yielded 122 relevant studies pertaining to exercise stress testing in pediatric heart disease. We received 59 responses to our survey from 33 unique institutions in the United States and Canada.

CONCLUSIONS

Twenty-one summaries were provided regarding exercise stress testing in pediatric patients with heart disease. Multicentered or national stress testing registries may allow for adequate sample sizes of rare pediatric diseases to allow for development of improved guidelines regarding the type and timing of stress testing.

Fontan-Associated Liver Disease

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

Methylated Arginine Metabolites as Biomarkers for Clinical Status and Response to Type 5 Phosphodiesterase Inhibition in Patients With Fontan Circulation

BACKGROUND

There is significant interest in NO pathway modulators, specifically type 5 phosphodiesterase inhibitors (PDE5is), to treat patients with a Fontan circulation. Trials, however, have had mixed results. The relationship between the NO pathway and clinical status in patients with Fontan circulation is a significant knowledge gap.

METHODS AND RESULTS

We performed targeted metabolomic analysis using liquid chromatography coupled to mass spectrometry to quantify plasma NO pathway metabolite concentrations from 2 well-characterized populations of patients with Fontan circulation: the Boston Adult Congenital Heart Disease Biobank and Fontan Udenafil Exercise Longitudinal studies. We investigated associations between NO metabolite concentrations and clinical outcomes, exercise capacity, and response to PDE5is. Increased plasma concentration of asymmetric dimethyl arginine (ADMA), an inhibitor of NO production, was associated with risk for hospitalization or death. Increased ADMA and symmetric dimethyl arginine (another inhibitor of NO production) concentrations were associated with decreased baseline exercise capacity among patients with Fontan circulation with <90% predicted peak oxygen uptake, and change in ADMA and symmetric dimethyl arginine concentrations were predictive of change in exercise capacity over time. Treatment with the PDE5i udenafil uncoupled this association. Finally, baseline ADMA and symmetric dimethyl arginine concentrations predicted response to PDE5is among patients with subnormal peak oxygen uptake.

CONCLUSIONS

Plasma concentrations of metabolites that inhibit NO flux are associated with negative clinical outcomes and worse exercise capacity. Moreover, metabolite shifts over time associated with increased NO flux are associated with improved exercise capacity. In patients with a Fontan circulation, the NO pathway modulators ADMA and symmetric dimethyl arginine may be useful as biomarkers of clinical status and predictive of response to PDE5is.

Urgent and emergent pediatric cardiovascular imaging

The need for urgent or emergent cardiovascular imaging in children is rare when compared to adults. Patients may present from the neonatal period up to adolescence, and may require imaging for both traumatic and non-traumatic causes. In children, coronary pathology is rarely the cause of an emergency unlike in adults where it is the main cause. Radiology, including chest radiography and computed tomography in conjunction with echocardiography, often plays the most important role in the acute management of these patients. Magnetic resonance imaging can occasionally be useful and may be suitable in more subacute cases. Radiologists' knowledge of how to manage and interpret these acute conditions including knowing which imaging technique to use is fundamental to appropriate care. In this review, we will concentrate on the most common cardiovascular emergencies in the thoracic region, including thoracic traumatic and non-traumatic emergencies and pulmonary vascular emergencies, as well as acute clinical disorders as a consequence of primary and postoperative congenital heart disease. This review will cover situations where cardiovascular imaging may be acutely needed, and not strictly emergencies only. Imaging recommendations will be discussed according to the different clinical presentations and underlying pathology.

Mental Health Care for Children with Heart Disease and Their Families: Practical Approaches and Considerations for the Pediatric and Pediatric Cardiology Clinician

Mental health conditions are a common comorbidity among children living with heart disease. Children with congenital heart disease are more likely to have a mental health condition than their unaffected peers or peers with other chronic illnesses, and mental health risk persists across their lifetime. While poorer mental health in adults with congenital heart disease is associated with worse overall health outcomes, the association between mental health and cardiac outcomes for children with heart disease remains unknown. Despite this, it is suspected that mental health conditions go undiagnosed in children with heart disease and that many affected children and adolescents do not receive optimal mental health care. In this article, we review mental health in congenital heart disease across the lifespan, across domains of care, and across diagnoses. Further directions to support mental health care for children and adolescents with heart disease include practical screening and access to timely referral and mental health resources.

Cardiac and Liver Fibrosis Assessed by Multiparametric MRI in Patients with Fontan Circulation

The abnormal hemodynamics in Fontan circulation due to persistently increased systemic venous pressure results in hepatic venous congestion and Fontan-associated liver disease. Combined assessment of cardiac and liver fibrosis and cardiac remodeling using multiparametric MRI in this context have not been fully explored. To evaluate cardiac and liver fibrosis and cardiac remodeling using multiparametric MRI in patients who have undergone Fontan procedures. Thirty-eight patients and 23 controls underwent cardiac and liver MRI examinations in a 3.0-T scanner. Mann-Whitney, Fisher exact test, and Spearman's correlation were applied to evaluate myocardial volumes, function, native cardiac and liver T1 mapping, ECVs and liver stiffness. The mean native cardiac T1 value (p = 0.018), cardiac ECV (p < 0.001), liver native T1 (p < 0.001), liver ECV (p < 0.001), and liver stiffness (p < 0.001) were higher in patients than controls. The indexed end-diastolic volume (EDVi) correlated with the myocardial ECV (r = 0.356; p = 0.033), native liver T1 (r = 0.571; p < 0.001), and with liver stiffness (r = 0.391; p = 0.015). In addition, liver stiffness correlated with liver ECV (r = 0.361; p = 0.031) and native liver T1 (r = 0.458; p = 0.004). An association between cardiac remodeling and cardiac and liver fibrosis were found in this population. The usefulness of MRI to follow cardiac and liver involvement in these patients is critical to improve treatment strategies and to prevent the need for combined liver and heart transplantation.

Adverse Effect of Bundle Branch Block on Exercise Performance in Patients with Fontan Physiology: From the Pediatric Heart Network Fontan Public Data Set

Patients with Fontan physiology have reduced exercise performance compared to their peers as well as a higher incidence of bundle branch block (BBB). This study aims to investigate the association between BBB and exercise performance in the Fontan population through a retrospective review of the Pediatric Heart Network Fontan study public use dataset. "Low Performers" were defined as ≤ 25th percentile (for Fontan patients) for each exercise parameter at anaerobic threshold (AT) for gender and age and "Normal Performers" were all other patients. A total of 303 patients with Fontan physiology who underwent exercise testing reached AT and had complete data for BBB. BBB occurred more frequently in Low Performers for VO2 [OR (95% CI): 2.6 (1.4, 4.8)] and Work [OR (95% CI): 2.7 (1.4, 5.1)], suggesting that BBB in the Fontan population is associated with reduced exercise performance. This data adds to the existing clinical evidence of the adverse effects of conduction abnormalities on single ventricle cardiac output and adds support for consideration of cardiac resynchronization and multi-site ventricular pacing in this patient population.

Volume challenge in women with congenital heart disease during reproductive age and pregnancy outcomes

BACKGROUND

Thanks to medical improvements in the care for patients with congenital heart disease (CHD), women with CHD reach reproductive age. Pregnancy is not without risk due to the cardiovascular changes that occur. University Hospitals Leuven use a standardised protocol, including a catheterisation and volume challenge, to assess these women before pregnancy. This protocol has never been evaluated.

OBJECTIVE

The primary aim was to evaluate this volume challenge protocol. The second objective was to investigate whether hemodynamic data obtained during cardiac catheterisation were associated with maternal and/or neonatal outcome.

METHODS

A single-centre, retrospective study was conducted. Primarily, changes in catheterisation measurements were evaluated. Second, correlation statistics investigated associations between catheterisation data and outcome.

RESULTS

Twenty-five women, with nine different CHDs were eligible for inclusion and underwent a catheterisation with volume challenge. Significant changes in pre- and post-volume challenge measurements were observed in the mean averaged systemic venous pressure (ASVP) (p < 0.001), diastolic and mean pulmonary artery pressures (p < 0.001), and the pulmonary capillary wedge pressure (p < 0.001). A negative correlation was observed between the pre-test ASVP and the neonatal gestational age at delivery (p = 0.002). Another negative correlation was found between the post-test cardiac index (CI) and gestational age at delivery (p = 0.049) and birthweight (p = 0.018).

CONCLUSION

The results suggest that higher ASVP is associated with lower gestational age at delivery. Remarkably, higher CI was related with lower gestational age and birthweight. However, our data do not support that a systematic volume challenge in women with CHD can be considered as a reliable prediction test.

Hemodynamic Effects of Altering Tidal Volume During Positive Pressure Ventilation in the Fontan Circulation: A Randomized Crossover Trial

BACKGROUND

Primary determinants of pulmonary blood flow in the Fontan circulation are low transpulmonary gradient and pulmonary vascular resistance (PVR). Changes in intrathoracic pressure during intermittent positive pressure ventilation can influence the transpulmonary gradient, PVR, pulmonary blood flow, and cardiac output. The aim of this study was to evaluate the effect of low (5 mL/kg) versus high (10 mL/kg) tidal volume (VT) ventilation on Fontan circulation hemodynamics.

METHOD

Postoperative patients with a Fontan circulation were enrolled in this single-center, randomized crossover trial. Patients, randomized to group 1 or 2, underwent a ventilation study sequence (baseline ventilation [7 mL/kg], then high VT [10 mL/kg] or low VT [5 mL/kg], then washout ventilation [7 mL/kg], followed by low [5 mL/kg] or high VT [10 mL/kg]) in the operating room at the end of the cardiac surgical procedure. Respiratory, hemodynamic, and transesophageal (TEE) measurements were recorded after 5 min in each ventilation condition. The primary aim of this study was to evaluate the effect of low VT ventilation (5 mL/kg) versus high VT ventilation (10 mL/kg) on transpulmonary gradient (Fontan pressure minus left atrial pressure). The secondary aim was to compare TEE measurements of pulmonary blood flow, stroke volume, and Fontan flow between low and high VT ventilation. We also compared standard hemodynamic and ventilation parameters for all ventilation conditions. Analysis was of paired data, calculating the between-treatment difference within participants across ventilation conditions.

RESULTS

Eleven patients were included in the final data analysis with a median [IQR] age of 5 [4, 11] years and weight of 16.3 [13.8, 31.6] kg. The mean (±SD) peak inspiratory pressure during low and high VT ventilation was 15.3 (±2.9) cmH2O and 22.2 (±3.7) cmH2O, respectively (difference -6.9, 95% CI -7.8, -5.9, p < 0.001). The mean airway pressure during low and high VT ventilation was 7.3 ± 0.8 and 8.7 ± 0.9 (difference -1.5, 95% CI -2.1, -0.8, p = 0.001) with a mean inspiratory time of 0.62 (±0.22) s and 1.21 (±0.55) s (difference -0.59, 95% CI -0.84, -0.34, p < 0.001), respectively. During low VT ventilation, the mean Fontan pressure was 13.3 (±1.8) mmHg compared to 12.3 (±2.5) mmHg for high VT ventilation (difference 0.8, 95% CI -0.5, 2.1, p = 0.18). The mean transpulmonary gradient was 7.0 ± 1.3 mmHg compared to 6.8 ± 1.2 mmHg during low and high VT ventilation, respectively (difference 0.2, 95% CI -0.2, 0.6, p = 0.21). We found no significant differences between low and high VT ventilation in TEE measures of pulmonary blood flow, stroke volume, and Fontan flow.

CONCLUSIONS

This randomized, crossover pilot trial of Fontan patients showed that a low VT ventilation (5 mL/kg) resulted in significantly lower peak and mean airway pressure compared with a high VT ventilation (10 mL/kg). However, there were no significant changes in transpulmonary gradient, mean Fontan pressure, or TEE parameters of stroke volume, pulmonary blood flow, or Fontan flow.

CLINICAL TRIALS REGISTRATION NUMBER

NCT04633343.

PRINCIPAL INVESTIGATOR

Manchula Navaratnam.

DATE OF REGISTRATION

November 11, 2020. Clinical Trials Registration Registry URL: https://clinicaltrials.gov/study/NCT04633343?term=Fontan%20ventilation&rank=3.

PRIOR PRESENTATIONS

Congenital Cardiac Anesthesia Society Annual Meeting Top Oral Abstract Presentation.

PRESENTER

Alexander R Schmidt, March 30th, 2023.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

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

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

Hypoplastic left heart syndrome (HLHS) becomes of age: Assessing the young adult with HLHS including the neoaorta/aortic arch

Hypoplastic left heart syndrome (HLHS) is one of the most complex congenital heart defects (CHD), characterized by a hypoplastic left ventricle (LV), dominant right ventricle (RV) and small left-sided heart structures. The introduction of the Norwood operation has significantly improved outcomes, with 5-year survival reported up to 65 %. Despite these advances, post-operative morbidity and mortality remain high, and the long-term complications in adult survivors represent a challenge. The number of HLHS patients with Fontan circulation is expected to double in the next 20 years, leading to a growing population requiring specialized care from adult congenital heart disease (ACHD) teams. This article reviews current management strategies for HLHS, outlines potential long-term complications, and highlights existing knowledge gaps. Specific considerations in this population include the assessment of the neo-aorta and aortic arch, and systemic RV dysfunction in the setting of a Fontan circulation. The proposed surveillance strategy emphasizes the need for vigilant monitoring and timely intervention to treat the complications unique to this population, ensuring better outcomes for HLHS patients reaching adulthood.

Reverse double switch operation for the borderline left ventricle

OBJECTIVE(S)

This study investigates outcomes of the reverse double switch operation (R-DSO) and ventricular switch, novel approaches for patients with D-looped borderline left hearts that utilize the morphologic right ventricle as the systemic ventricle and the hypoplastic left ventricle as the subpulmonary ventricle.

METHODS

This retrospective review analyzed early outcomes of children who underwent R-DSO/ventricular switch at a single institution between 2015 and 2023. Our primary end points were right ventricular (RV) function and tricuspid regurgitation. Secondary outcomes included mortality, reoperation, and perioperative complications.

RESULTS

Twenty-eight patients underwent either R-DSO (n = 19) or ventricular switch (n = 9). In 19 patients, a decompressing bidirectional cavopulmonary shunt was utilized, creating a reverse 1.5 switch. Median age at R-DSO/ventricular switch was 3.1 years (range, 9 months-12 years). At a median follow-up of 1.0 year (range, 38 days-7.2 years), no mortalities or heart transplants had occurred. Mild-moderate or greater RV dysfunction was detected in 4 patients, and mild-moderate or worse tricuspid regurgitation was also detected in 4 patients. Three patients required reoperations. Preoperative RV ejection fraction <55% was associated with higher incidence of postoperative RV dysfunction.

CONCLUSIONS

The R-DSO/VS strategy is an alternative to single-ventricle palliation or anatomic biventricular repair in the borderline left heart. Concerns for RV dysfunction and tricuspid regurgitation mandate close monitoring. Patients with preoperative RV dysfunction may be at risk for postoperative RV dysfunction. Further studies with longer follow-up are needed to delineate outcomes in comparison to the Fontan pathway and identify optimal candidates for this novel strategy.

Acute Effects of Enhanced External Counterpulsation in Adults With Fontan Circulation

BACKGROUND

Patients with Fontan circulation exhibit reduced cardiac output.

OBJECTIVES

The purpose of this study was to study the safety and acute hemodynamic effects of enhanced external counterpulsation (EECP) in a cohort of Fontan patients.

METHODS

This was a pilot study of ambulatory adults with Fontan circulation at a single, large-volume adult congenital heart disease center. Patients underwent 1 hour of EECP divided into 20-minute stages (80 mm Hg, 160 mm Hg, and 240 mm Hg). Transthoracic echocardiography and pulmonary blood flow (PBF) measurement were performed at baseline, during each stage of EECP, and after EECP completion. Patients were monitored for symptoms throughout. For the primary endpoint, PBF was compared between baseline and EECP at target pressure of 240 mm Hg.

RESULTS

There were 23 patients enrolled (52% male). The median age was 30.9 years (27.8, 37.8). Twenty-two patients (96%) completed a full hour of EECP. EECP pressure was reduced in the final stage for 3 patients due to discomfort. No patients reported adverse symptoms during EECP. PBF increased from 4.5 L/min at baseline to 5.2 L/min during the final stage of EECP (P = 0.001) and returned to baseline post-EECP (4.2 L/min [P = 0.05 vs baseline]). Oxygen saturation remained increased compared to baseline throughout EECP treatment (baseline: 93.0%, 80 mm Hg: 94.3% [P = 0.008], 160 mm Hg: 94.6% [P ≤ 0.001], 240 mm Hg: 94.6% [P = 0.007]). There was no change in mean arterial pressure, heart rate, ventricular function, or valvar regurgitation.

CONCLUSIONS

Our results suggest that EECP is well-tolerated in adult Fontan patients and acutely improves PBF. Further study is warranted to explore its longer-term therapeutic effects.

Assessing and Addressing Cardiovascular and Obstetric Risks in Patients Undergoing Assisted Reproductive Technology: A Scientific Statement From the American Heart Association

The use of assisted reproductive technology (ART) is growing, both to assist individuals with infertility and for fertility preservation. Individuals with cardiovascular disease (CVD), or risk factors for CVD, are increasingly using ART. Thus, knowing how to care for patients undergoing ART is important for the cardiovascular clinician. In this scientific statement, we review the ART process and known short-term and long-term risks associated with ART that can adversely affect patients with CVD. We review current knowledge on risks from ART for specific cardiac conditions and provide a suggested approach to evaluating and counseling patients with CVD contemplating ART as well as suggested management before and during the ART process. Individuals with CVD are at increased risk for pregnancy complications, and management of this unique population has been discussed previously. The focus of this scientific statement is on ART. Therefore, discussions on risk assessment, counseling, and management of individuals with CVD during pregnancy are limited, and established guidelines are referenced.

Are Arrhythmias Adequately Incorporated into Studies on Long-Term Outcomes After the Fontan Operation?

Arrhythmias are common after the Fontan operation and increase risk of morbidity and mortality. Their impact on late outcomes remains poorly understood. Our objective was to assess whether long-term studies after the Fontan incorporated the impact of arrhythmia characteristics on outcome. We reviewed the literature since 2005 for studies evaluating the impact of multiple risk factors on long-term outcomes and mortality after the Fontan. Studies focusing only on one or two risk factors (including arrhythmias) and those with a mean follow-up < 10 years were excluded. Of the 17 studies analyzed, only six mentioned rhythm at follow-up. Nine lumped all arrhythmias (tachyarrhythmia, bradyarrhythmia, paced rhythm, early and late arrhythmia) into one single category. Only eight of the 17 studies reported the incidence of tachyarrhythmias in detail and only two studies described bradyarrhythmias in detail as sinus or atrioventricular (AV) node dysfunction subgroups. Five studies reported on treatment of tachyarrhythmias including Fontan revision surgeries, catheter ablation, pacemaker placement and or the use of antiarrhythmic drugs. However, only one included information on the impact of treatment on outcomes. Out of 15 studies that conducted a multivariate analysis of Fontan outcomes, arrhythmia was included in the univariate model in 14 and in the multivariate model in 9. Overall, we found most studies on late outcomes after the Fontan do not include rhythm and arrhythmia characteristics in data collection and analysis. Incorporating more granular rhythm information in large databases and in multivariate analyses will help better determine and contextualize the impact of arrhythmias on outcomes after the Fontan.

Hypoxia-Induced Cardiopulmonary Remodeling and Recovery: Critical Roles of the Proximal Pulmonary Artery, Macrophages, and Exercise

Hypoxemia impairs cardiopulmonary function. We investigated pulmonary artery remodeling in mice exposed to chronic hypoxia for up to five weeks and quantified associated changes in cardiac and lung function, without or with subsequent normoxic recovery in the absence or presence of exercise or pharmacological intervention. Hypoxia-induced stiffening of the proximal pulmonary artery stemmed primarily from remodeling of the adventitial collagen, which resulted in part from altered inter-cellular signaling associated with phenotypic changes in the mural smooth muscle cells and macrophages. Such stiffening appeared to precede and associate with both right ventricular and lung dysfunction, with changes emerging to similar degrees regardless of the age of onset of hypoxia during postnatal development. Key homeostatic target values of the wall mechanics were recovered by the pulmonary arteries with normoxic recovery while other values recovered only partially. Overall cardiopulmonary dysfunction due to hypoxia was similarly only partially reversible. Remodeling of the cardiopulmonary system due to hypoxia is a complex, multi-scale process that involves maladaptations of the proximal pulmonary artery.

Cardiopulmonary Exercise Test Interpretation Across the Lifespan in Congenital Heart Disease: A Scientific Statement From the American Heart Association

Survivorship from congenital heart disease has improved rapidly secondary to advances in surgical and medical management. Because these patients are living longer, treatment and disease surveillance targets have shifted toward enhancing quality of life and functional status. Cardiopulmonary exercise testing is a valuable tool for assessing functional capacity, evaluating cardiac and pulmonary pathology, and providing guidance on prognosis and interventional recommendations. Despite the extensive evidence supporting the ability of cardiopulmonary exercise testing to quantitatively evaluate cardiovascular function, there remains confusion on how to properly interpret cardiopulmonary exercise testing in patients with congenital heart disease. The purpose of this statement is to provide a lifespan approach to the interpretation of cardiopulmonary exercise testing in patients with congenital heart disease. This is an updated report of the American Heart Association's previous publications on exercise in children. This evidence-based update on the significance of cardiopulmonary exercise testing findings in pediatric, adolescent, and adult patients with various congenital cardiac pathologies and surgically modified physiology is formatted in a way to guide cardiopulmonary exercise testing interpretation practically for the clinicians and exercise physiologists who care for patients with congenital heart disease. Focus is placed on the indications for exercise testing, expected findings, and how exercise testing should guide the management of patients with various congenital heart disease subtypes. Areas for future intervention that could lead to improved care and outcomes for those with congenital heart disease are noted.

Congenital Heart Disease After Mid-Age: From the "Grown-Up" to the Elderly

Early surgery and improved medical care have led to the increased survival of neonates with congenital heart disease (CHD), who now commonly reach adulthood. Among adults with CHD, a growing subgroup is represented by middle-aged and even elderly patients. In this elderly population, acquired cardiac and extracardiac comorbidities represent the main cause of morbidity and mortality; the control and correction of cardiovascular risk factors or an appropriate check for extracardiac complications (such as malignancies) is therefore of paramount importance. Complications and frailty syndrome appear to occur earlier in ACHD than in the general population due to a frequent discrepancy between chronological and biological age. Multiple stressors throughout life (hemodynamic abnormalities, cardiac operations and interventional procedures, the placement of foreign materials) that result in a chronic inflammatory response are among the leading causes of premature senescence. This review is aimed at assessing the characteristics and special needs of this elderly ACHD population with a view to proposing novel models for the organization of extended care.

Review of rhythm disturbances in patient after fontan completion: epidemiology, management, and surveillance

Purpose

The Fontan operation is commonly associated with alterations in heart rhythms, both tachycardic and bradycardic. Despite modifications to attempt to mitigate these complications, arrythmias still frequently occur. The purpose of this review is to examine the literature regarding the scope of the problem, therapeutic options, and current recommendations regarding screening and surveillance.

Recent findings

Modifications to the original Fontan procedure, antiarrhythmic medications, and improvements in catheter ablation procedures have improved the management of patients with arrhythmias following Fontan palliation. There is growing interest in the role of junctional rhythm in the role of Fontan dysfunction. While chronotropic incompetence has often been blamed for poor exercise testing, there is evidence that decreased performance may be related to ventricular filling and Fontan hemodynamics.

Summary

Tachyarrhythmias are an important cause of mortality and morbidity after the Fontan operation. Prompt and aggressive management of arrhythmias with the goal of maintaining sinus rhythm is vital. Management strategies such as anti-arrhythmic medications, ablation, anti-tachycardia pacing and Fontan conversion should be seen as complementary and used early to prevent hemodynamic deterioration. Bradyarrythmias likely also contribute to Fontan failure. Pacing is the primary management strategy with evidence supporting use of atrial pacing. However, ventricular pacing seems to often lead to deleterious effects. Current guidelines recommend surveillance with Holter monitor every 2-3 years in adolescents and every 1-2 years in adults. Future directions for research include further assessment of junctional rhythm and its management as well as further identifying patients in which pacing would be beneficial.

Long-Term Outcomes of Fontan Patients With an Extracardiac Conduit: A Systematic Review and Meta-Analysis

BACKGROUND

Although Fontan palliation improves survival, it poses a large burden of lifelong morbidity. In extracardiac Fontan (ECF) patients, for example, conduit stenosis developing over time has been associated with Fontan failure and other adverse outcomes. This systematic review, for the first time, synthesized existing data on various long-term outcomes of ECF patients, including change in conduit and associated outcomes.

METHODS

We searched the Medline, Embase, and Cochrane indexes from inception to 2023 and included studies reporting separate results for ECF patients with a follow-up time of at least 3 years. Full-text studies were assessed for risk of bias. We summarised information on the study, patient characteristics, and outcomes narratively and with the use of descriptive tables. Meta-analysis was performed to calculate pooled incidence rates of adverse events.

RESULTS

We included 61 full-text studies, with most studies published after 2009 (77.0%) and using a retrospective cohort design (76.2%). The pooled incidence rates per 100 person-years were for arrhythmia 1.8 (95% confidence interval [CI] 1.3-2.6), thrombotic events 0.2 (95% CI 0.1-0.4), protein-losing enteropathy 0.7 (95% CI 0.5-1.0), conduit obstruction 0.7 (95% CI 0.3-1.5), reoperation 1.9 (95% CI 1.1-3.4), and late death 0.3 (95% CI 0.2-0.5). The ranges of hemodynamic and exercise parameters and findings from studies reporting changes in conduit size and liver disease were reported.

CONCLUSIONS

Although many studies have largely focused on long-term survival, several other adverse outcomes require further research to develop consensus-based definitions and approaches for evaluations, especially as the ECF population ages. (PROSPERO: CRD42024533080).

Heart-Liver Interplay in Patients with Fontan Circulation

Background: The Fontan procedure has provided pediatric patients suffering from severe congenital heart disease the opportunity to reach adulthood. Increasingly, we encounter the liver repercussions of Fontan circulation, alongside a decline in heart function and exercise performance. This study aims to identify the univentricular heart malformations that are most susceptible to liver dysfunction; assess which markers of liver injury are essential for multidisciplinary clinical follow-up of Fontan patients; determine the optimal approach for evaluating liver function in Fontan patients; and explore how a congenital cardiology team can interpret the data and respond effectively to signs of organ failure. Methods: Cross-sectional clinical study including patients who underwent a Fontan procedure at the University Hospital of Padua between 1982 and 2017. Patients were admitted for elective hospitalization between June 2021 and June 2022 and underwent clinical assessment, laboratory tests, and instrumental examinations. Results: Seventy patients were included in the study. On admission, 48 patients (72%) were in New York Heart Association (NYHA) functional class I, and the cardiopulmonary exercise test was normal for age and gender. At laboratory tests, 56% of patients showed changes in NTproBNP values, most of whom had right-sided ventricular morphology. Liver function tests showed abnormal Gamma-Glutamyl Transferase (GGT) blood levels in 68%. On cardiac imaging, at least moderate atrioventricular valve insufficiency was found in 9% of cases. Fibroscan showed altered hepatic stiffness values in 25% of cases. Statistical analysis showed that systemic atrioventricular valve (SAVV) dysfunction was significantly associated with a reduction of maximum oxygen consumption (VO2 max) and hepatic stiffness. Conclusions: SAVV dysfunction is significantly responsible for worse functional outcomes and the development of hepatic fibrosis due to an increase in venous congestion. Setting up a careful multidisciplinary follow-up in these patients is mandatory for early detection of complications, prompt treatment, and better outcomes.

Serial changes of systemic ventricular function and atrioventricular valve function in patients with failing Fontan

OBJECTIVES

This study investigated the longitudinal changes in ventricular function and atrioventricular valve function to clarify the timing and the mechanisms of failing Fontan.

METHODS

Patients who underwent total cavopulmonary connection between 1994 and 2023 were reviewed, and longitudinal echocardiographic examinations of ventricular function and atrioventricular valve regurgitation were analysed.

RESULTS

A total of 650 patients were included. The most frequent primary diagnosis was hypoplastic left heart syndrome in 175 patients. Dominant right ventricle was observed in 337 patients (51.8%). The median age at total cavopulmonary connection was 2.3 (1.8-3.3) years. Failing Fontan was observed in 78 patients (12%) during the median follow-up of 6.2 years. Among them, dominant right ventricle was observed in 51 patients (65.4%). Patients with protein-losing enteropathy or plastic bronchitis (n = 37) developed Fontan failure early (median 2.6 years post-total cavopulmonary connection). Still, patients maintained ventricular function (93.1% normal at 5 years) and atrioventricular valve competence (no case of moderate/severe regurgitation at 5 years) over time. Patients who developed failing Fontan associated with progression of heart failure (n = 41) had later onset (median 8.3 years post-total cavopulmonary connection) but indicated progressive ventricular dysfunction (68.3% normal at 5 years, 53.8% normal at 10 years) and atrioventricular valve regurgitation (12.3% moderate/severe at 5 years, 15.3% moderate/severe at 10 years).

CONCLUSIONS

Patients with failing Fontan indicated different serial ventricular and atrioventricular valve function profiles. Ventricular function was preserved in failing Fontan patients with protein-losing enteropathy or plastic bronchitis, whereas progressive ventricular dysfunction was observed in failing Fontan patients with heart failure.

Novel lateral tunnel Fontan operation in children promotes continued pathway growth into adulthood

Objective

Most Fontan operation techniques currently used in children are limited by a blood flow pathway with no growth potential. The external pericardial lateral tunnel Fontan is a novel technique using the patient's pedicled pericardium and atrial wall in situ to create a Fontan pathway. We hypothesize that viable, autologous tissue will allow growth potential of the pathway and adapt to increasing physiologic demands of somatic growth.

Methods

We performed a single-center retrospective review of serial echocardiographic measurements of the inferior vena cava junction and mid tunnel in patients with an external pericardial lateral tunnel Fontan. Linear mixed model and Pearson correlation tests were used for analysis of changes in pathway size with time and body surface area.

Results

A total of 1592 echocardiographic studies from 172 patients up to 23 years after the procedure were identified. Significant enlargement of the pathway at the inferior vena cava junction and mid tunnel was observed over time (P < .0001, P < .0001, respectively). There is a strong positive correlation between increasing size of the inferior vena cava junction and increasing body surface area (R = 0.81, P < .0001). There is also a strong positive correlation between increasing size of the mid tunnel with increasing body surface area (r = 0.67, P < .0001).

Conclusions

The external pericardial lateral tunnel Fontan technique creates a Fontan pathway that enlarges into adulthood. The correlation of increasing pathway size with increasing body surface area suggests pathway growth, responding to increasing physiologic demands of somatic growth into adulthood. Further studies are needed to investigate the impact of this novel technique on Fontan physiology and long-term patient outcomes.

Augmentation of the skeletal muscle pump alleviates preload failure in patients after Fontan palliation and with orthostatic intolerance

While the pathophysiology affecting patients after Fontan palliation versus those with orthostatic intolerance is quite different, a common therapeutic approach exists. Exercise training, specifically augmenting the lower extremity skeletal muscle pump, improves the suboptimal haemodynamics of "preload failure" and thus clinical outcomes for each patient group. In this review, we will describe the problematic physiology affecting these patients, examine the anatomy and haemodynamics of the skeletal muscle pump, and finally review how exercise benefits both groups of patients through augmentation of musculovenous force.

Native liver T1 mapping on magnetic resonance imaging for an evaluation of congestive liver injury in children with congenital heart disease

Fontan-associated liver disease (FALD) may be caused by chronic liver congestion due to high central venous pressure (CVP). Recently, the usefulness of liver native T1 mapping in magnetic resonance imaging (MRI) in adulthood has been reported. To evaluate the usefulness of native liver T1 mapping in children with congenital heart disease (CHD), we investigated the utility of native liver T1 relaxation time (LT1) in pediatric Fontan patients in comparison to other CHDs. Correlations between LT1 and laboratory biomarkers or hemodynamic data were also assessed. A total of 155 patients with CHD (biventricular repair, n = 42; bidirectional Glenn circulation, n = 38; and Fontan circulation, n = 75) underwent blood tests, cardiac catheterization, and cardiac MRI within 48 h. Both CVP and LT1 levels were higher in Fontan patients than in bidirectional Glenn and biventricular patients. There were significant correlation in the overall population and weak correlation in Fontan patients between CVP and LT1(correlation coefficient 0.644 [0.541-0.728] and 0.244 [0.0179-0.446], P < 0.001 and 0.035, respectively). Among the laboratory data, the multiple linear regression analysis revealed that the fibrosis-4 index and alanine aminotransferase were significantly correlated with LT1 in the overall population (P = 0.008,0.012), and the fibrosis-4 index was correlated with LT1 in Fontan patients (P = 0.019). LT1 might have some role to predict elevated CVP and liver injury in children with CHD.

Efficacy and safety of macitentan in Fontan-palliated patients: 52-week randomized, placebo-controlled RUBATO Phase 3 trial and open-label extension

OBJECTIVES

The efficacy and safety of macitentan, an endothelin receptor antagonist, were assessed in a 52-week, prospective, multicenter, double-blind, randomized, placebo-controlled, parallel-group study assessing the efficacy and safety of macitentan in Fontan-palliated adult and adolescent patients (RUBATO-DB) and an open-label extension trial (RUBATO-OL).

METHODS

Patients aged 12 years and older with New York Heart Association functional class II or III underwent total cavopulmonary connection more than 1 year before screening and showed no signs of Fontan failure/clinical deterioration. In RUBATO-DB, the primary efficacy end point was change in peak oxygen consumption from baseline to week 16; secondary end points were change from baseline over 52 weeks in peak oxygen consumption and change in mean count/minute of daily physical activity via accelerometer from baseline to week 16. Safety was assessed throughout both studies.

RESULTS

In RUBATO-DB, 137 patients were randomized to macitentan 10 mg (n = 68) or placebo (n = 69); 92.7% completed 52-week double-blind treatment. At week 16, mean ± SD change in peak oxygen consumption was -0.16 ± 2.86 versus -0.67 ± 2.66 mL/kg/minute with macitentan versus placebo (median unbiased treatment difference estimate, 0.62 mL/kg/minute [99% repeated CI, -0.62 to 1.85]; P = .19). No treatment effect was observed in either of the secondary end points. During RUBATO-DB, most common adverse events with macitentan were headache, nasopharyngitis, and pyrexia. Across RUBATO-DB and RUBATO-OL, most common adverse events were COVID-19, headache, and fatigue. RUBATO-OL was prematurely discontinued because RUBATO-DB did not meet its primary or secondary end point.

CONCLUSIONS

The primary end point of RUBATO-DB was not met; macitentan did not improve exercise capacity versus placebo in patients with Fontan palliation. Macitentan was generally well tolerated over long-term treatment.

Isolated loss of vaccine immunity in the protein losings syndrome in a patient with a reverse one and a half ventricle palliation ("failing Fontan-like physiology")

BACKGROUND

A subgroup of CHDs can only be treated palliatively through a Fontan circulation. In case of a failing Fontan situation, serum proteins are lost unspecifically and can also lead to a loss of vaccine antibodies. In a failing Fontan situation, heart transplantation may be the only feasible option.

PATIENT

We describe a 17-year-old patient born with a hypoplastic left heart complex, who underwent Fontan completion at the age of 4 years and developed a failing Fontan physiology. Therefore, a Fontan takedown with creation of a reverse 1½-circulation was performed. Multiple exacerbations of protein losing enteropathy occurred with a hypoproteinaemia, hypalbuminaemia, and hypogammaglobulinaemia. The patient was hospitalised several times and treated with intravenous application of immunoglobulins and albumin for symptom control. Before one of this substitutions, the immunoglobulin G against measles, mumps, and rubella was determined: the patient's serum demonstrated a positive measles and rubella, but mumps was negative. After administration of the iv-therapy, the lacking antibodies were replenished, and there was a positive test for mumps.

METHOD

Serum samples were analysed by neutralisation test and enzyme-linked immunosorbent assay (ELISA).

CONCLUSION

Although the patient had been vaccinated according to national guidelines, we saw an intermittent immune deficiency for mumps, but not for rubella and measles. For patient with a failing Fontan circulation, we recommend to test to vaccine antibodies for mumps, measles, and rubella with an ELISA an if its negative with a neutralisation test, especially in view of a possible heart transplantation to find a possible immune deficiency.

Wellbeing and quality of life among parents of individuals with Fontan physiology

PURPOSE

To examine global and health-related quality of life (QOL) among parents of individuals with Fontan physiology and determine associations with sociodemographic, parent and child-related health, psychological, and relational factors.

METHODS

Parents participating in the Australian and New Zealand Fontan Registry (ANZFR) QOL Study (N = 151, Parent Mean age = 47.9 ± 10.2 years, age range: 31.6-79.6 years, 66% women; child Mean age = 16.3 ± 8.8, age range: 6.9-48.7 years, 40% female) completed a series of validated measures. Health-related QOL was assessed using the PedsQL 4.0 Core Generic Scales for adults and global QOL was assessed using a visual analogue scale (0-10).

RESULTS

Most parents (81%) reported good global QOL (≥ 6), consistent with broader population trends. Nearly one-third of parents (28%) reported at-risk health-related QOL (based on total PedsQL scores) with physical functioning most affected (44%). Psychological factors, including psychological stress and sense of coherence, emerged as the strongest correlates of global and health-related QOL, explaining an additional 16 to 30% of the variance (using marginal R2). Final models explained 35 and 57% and of the variance in global and health-related QOL, respectively (marginal R2). Relational factors, including perceived social support and family functioning contributed minimally when analyzed alongside psychological variables.

CONCLUSION

While parents of individuals with Fontan physiology report good global QOL, challenges in health-related QOL exist. We identified key psychological, sociodemographic, and health-related factors associated with parental QOL outcomes. These data may aid early identification of physical and psychosocial difficulties and guide targeted health resource allocation for this population.

Pregnancy and cardiovascular outcomes among patients post Fontan surgery: a 25-year single-centre retrospective cohort study

INTRODUCTION

Data on the characteristics and outcomes of pregnancy and among patients with Fontan physiology are limited. We aimed to evaluate the immediate and long-term outcomes among these patients who were followed at our centre.

METHODS

We included adult patients who had undergone Fontan surgery for congenital heart disease and were pregnant between 1994 and 2021. We examined maternal and obstetric outcomes.

RESULTS

In a cohort of 109 patients following Fontan procedure, 51 patients were women, and 19 patients (37%) had a pregnancy during the follow-up period, accounting for a total of 46 pregnancies. Intrauterine growth retardation of the fetus was common, observed in 23% of all pregnancies and 50% of live births. The main fetal complication was prematurity, observed in 43% of all pregnancies and 90% of live birth. The maternal complications included pre-eclampsia (one patient), placental detachment (one patient), acute heart failure exacerbation (one patient), arrhythmia (three atrial arrhythmias) and major peripartum haemorrhage (two patients), with no peripartum death.

CONCLUSIONS

Over one-third of women with Fontan physiology in our cohort had a documented pregnancy. Maternal and obstetric complications were common among these patients, and expanded long-term data is needed. Limitations, including small sample size and survival bias, may have underestimated the risk of adverse outcomes in this cohort.

Blood Biomarkers as a Non-Invasive Method for the Assessment of the State of the Fontan Circulation

The Fontan operation has become the primary palliative treatment for patients with a functionally univentricular heart. The population of patients with Fontan circulation is constantly growing and aging. As the number of Fontan patients surviving into adulthood increases, there is a clear need for research on how best to follow these patients and manage their complications. Monitoring blood biomarkers is a promising method for the non-invasive assessment of the Fontan circulation. In this article, we provide a comprehensive review of the available evidence on this topic. The following biomarkers were included: natriuretic peptides, red blood cell distribution width (RDW), cystatin C, high-sensitivity C-reactive protein, vitamin D, parathyroid hormone, von Willebrand factor, carbohydrate antigen 125, lipoproteins, hepatocyte growth factor, troponins, ST2 protein, galectin-3, adrenomedullin, endothelin-1, components of the renin-angiotensin-aldosterone system, norepinephrine, interleukin 6, tumor necrosis factor α, and uric acid. We did not find strong enough data to propose evidence-based recommendations. Nevertheless, significantly elevated levels of brain natriuretic peptide (BNP)/N-terminal prohormone of BNP (NT-proBNP) are most likely associated with the failure of the Fontan circulation. The use of the RDW is also promising. Several biomarkers appear to be useful in certain clinical presentations. Certainly, robust longitudinal, preferably multicenter, prospective studies are needed to determine the sensitivity, specificity, evidence-based cut-off values and overall predictive value of different biomarkers in monitoring Fontan physiology.

Experience with SGLT2 Inhibitors in Patients with Single Ventricle Congenital Heart Disease and Fontan Circulatory Failure

Heart failure is the leading cause of morbidity and mortality in patients with Fontan circulation. Sodium-glucose-cotransporter 2 inhibitors (SGLT2i) have become a mainstay of heart failure therapy in adult patients, however, there remains a paucity of literature to describe its use in pediatric heart failure patients, especially those with single ventricle physiology. We describe our early experience using SGLT2i in patients with single ventricle congenital heart disease surgically palliated to the Fontan circulation. We conducted a single-center retrospective chart review of all patients with Fontan circulation who were initiated on an SGLT2i from January 1, 2022 to March 1, 2023. Patient demographics, diagnoses, clinical status, and other therapies were collected from the electronic medical record. During the study period, 14 patients (median age 14.5 years, range 2.0-26.4 years) with Fontan circulation were started on a SGLT2i. Mean weight was 54 kg (range 11.6-80.4 kg). Median follow-up since SGLT2i initiation was 4.1 months (range 13 days-7.7 months). Four patients had a systemic left ventricle and 10 had a systemic right ventricle. Half the patients had Fontan Circulatory Failure with reduced Ejection Fraction (FCFrEF) of the systemic ventricle and the other half had Fontan Circulatory Failure with preserved Ejection Fraction (FCFpEF) of the systemic ventricle. In addition, 3 patients experienced Protein Losing Enteropathy (PLE) and 2 patients had plastic bronchitis, one of whom also was diagnosed with chylothorax. There were no genitourinary infections, hypoglycemia, ketoacidosis, hypotension or other significant adverse effects noted in our patient population. One patient experienced significant diuresis and transient acute kidney injury. Patients with FCFrEF showed a decrease in natriuretic peptide levels. Given the lack of proven therapies, demonstrated benefits of SGLT2i in other populations, and some suggestion of efficacy in Fontan circulation, further study of SGTLT2i in patients with Fontan circulation is warranted.

Magnetic resonance elastography is useful to determine the severity of liver fibrosis according to liver biopsy in post-fontan patients

OBJECTIVE

The reliability of various modalities for assessing and monitoring Fontan-associated liver disease compared to liver biopsy remains an intriguing subject of inquiry. Our objective was to assess the efficacy of multiple modalities in comparison to liver histology for evaluating liver fibrosis in post-Fontan patients.

METHODS

We conducted a cross-sectional study involving Fontan patients without known liver disease. Eligible patients underwent cardiac and hepatic evaluations, including ultrasound liver elastography, magnetic resonance elastography (MRE) of the liver, computerized tomography (CT) scan of the upper abdomen, echocardiography, cardiac catheterization, and liver biopsy. The severity of liver fibrosis was categorized using the METAVIR score derived from liver biopsy results: F0/F1 indicated no or mild fibrosis, F2 indicated significant fibrosis, F3 indicated advanced fibrosis and F4 indicated cirrhosis.

RESULTS

A total of 38 patients (mean age 21 ± 6.5 years, 52.6% female) were included in the cross-sectional study, with a mean time elapsed since the Fontan operation of 13 years. Parameters obtained from echocardiography, ultrasound liver elastography, and CT scan of the upper abdomen did not exhibit significant differences among the groups. Notably, liver biopsy revealed advanced cirrhosis in 23 out of 38 patients and none were diagnosed with hepatocellular carcinoma. Multivariate logistic regression analysis demonstrated that the factor significantly associated with significant liver fibrosis or cirrhosis in post-Fontan patients was liver stiffness with MRE > 4.4 kPa [OR 13.5 (95% CI 1.2-152.2)].

CONCLUSIONS

Our findings suggest that post-Fontan patients with liver stiffness of MRE > 4.4 kPa should undergo further investigation. These results contribute to understanding the liver fibrosis assessment in post-Fontan patients and highlight the importance of MRE in predicting significant liver disease.

Quality of Life in the Danish Fontan Population is Unchanged Over the Past Decade-A Nationwide Longitudinal Study

Knowledge about health-related quality of life (HRQoL) over time in Fontan patients is sparse. We aimed to describe HRQoL over a ten-year period in a population-based Fontan cohort. Further, we compared HRQoL in Fontan patients with the general population. In 2011, Danish Fontan patients were invited to participate in a nationwide study assessing HRQoL. Depending on age, 152 participants filled out either the Pediatric Quality of Life Inventory or the 36-Item Short Form Health Survey. After a decade, patients from the initial study were invited to participate in a follow-up study. All were given the same questionnaire as in the first study, plus the 12-Item Short Form Health Survey (SF-12) as part of the Danish National Health Survey. HRQoL over time was described, and SF-12 scores were compared with the general population. A total of 109 Fontan patients completed the questionnaires in both studies. The mean patient age was 14.9 ± 6.6 years and 25.6 ± 6.5 years respectively. Despite an increase in complications, HRQoL did not decrease during the study period. Physical HRQoL scores were lower than mental HRQoL scores at both time points. The SF-12 physical component score was significantly lower in Fontan patients than in the general population (median score 52 vs. 56, p < 0.001), while the SF-12 mental component score was comparable (median score 51 vs. 50, p = 0.019). HRQoL remained stable over a ten-year period in a contemporary Danish Fontan cohort. Still, the physical HRQoL remained significantly lower than that of the general population.

Over 100 Fontan Patients on Systemic Ventricular Assist Device Support: An ACTION Update

As the Fontan population grows, understanding successful strategies for ventricular assist device (VAD) support of the failing Fontan circulation is needed. We performed a retrospective analysis of patients with Fontan circulation and systemic VAD support in the Advanced Cardiac Therapies Improving Outcomes Network (ACTION) registry. Competing outcomes and Kaplan-Meier estimated survival methods were used. Between January 2012 and December 2022, 106 Fontan patients underwent VAD implant (median age 10 years, 20% age ≥18 years). At time of implant, 58% were on greater than or equal to 2 inotropes, 26% on extracorporeal membrane oxygenation (ECMO), and 41% intubated. Since 2018, there have been more patients implanted at INTERMACS profile 1 or 2 (88% vs. 71%, p = 0.02) and on inotropic support (95% vs. 76%, p = 0.01). Median duration of VAD support was 113 (interquartile range (IQR): 43-266) days. At 12 months post-VAD implant, 53% were transplanted, 27% were alive on device, 2% had successful recovery, and 18% had died. Overall, 75% experienced greater than or equal to 1 adverse event, with bleeding, infection, and neurologic dysfunction most common. Despite high acuity at the time of VAD implant and high rate of adverse events, the majority of Fontan patients were transplanted or still alive on device at 12 months post-VAD implant.

The molecular mechanisms of cardiac development and related diseases

Cardiac development is a complex and intricate process involving numerous molecular signals and pathways. Researchers have explored cardiac development through a long journey, starting with early studies observing morphological changes and progressing to the exploration of molecular mechanisms using various molecular biology methods. Currently, advancements in stem cell technology and sequencing technology, such as the generation of human pluripotent stem cells and cardiac organoids, multi-omics sequencing, and artificial intelligence (AI) technology, have enabled researchers to understand the molecular mechanisms of cardiac development better. Many molecular signals regulate cardiac development, including various growth and transcription factors and signaling pathways, such as WNT signaling, retinoic acid signaling, and Notch signaling pathways. In addition, cilia, the extracellular matrix, epigenetic modifications, and hypoxia conditions also play important roles in cardiac development. These factors play crucial roles at one or even multiple stages of cardiac development. Recent studies have also identified roles for autophagy, metabolic transition, and macrophages in cardiac development. Deficiencies or abnormal expression of these factors can lead to various types of cardiac development abnormalities. Nowadays, congenital heart disease (CHD) management requires lifelong care, primarily involving surgical and pharmacological treatments. Advances in surgical techniques and the development of clinical genetic testing have enabled earlier diagnosis and treatment of CHD. However, these technologies still have significant limitations. The development of new technologies, such as sequencing and AI technologies, will help us better understand the molecular mechanisms of cardiac development and promote earlier prevention and treatment of CHD in the future.

Peak Oxygen Consumption Scaled to Body Composition Is Associated With Mortality and Morbidity in People With a Fontan Circulation

BACKGROUND

Peak oxygen consumption (peak V ̇ $$ \dot{\mathrm{V}} $$ O2) is traditionally scaled by body mass, but it is most appropriately scaled by fat-free mass. However, it is unknown whether peak V ̇ $$ \dot{\mathrm{V}} $$ O2 scaled by fat-free mass is associated with mortality and morbidity in people with a Fontan circulation. The aim of this study was to assess the associations between different expressions of peak V ̇ $$ \dot{\mathrm{V}} $$ O2 with mortality and morbidity in people with a Fontan circulation.

METHODS AND RESULTS

Eighty-seven participants (aged 24.1±7.3 years; 53% women) with a Fontan circulation completed a cardiopulmonary exercise test and a dual-energy x-ray absorptiometry scan. Cox proportional hazard regressions models assessed the association (hazard ratio [HR]) between different expressions of peak V ̇ $$ \dot{\mathrm{V}} $$ O2 with a composite outcome of Fontan failure (FF). Participants were followed up for a median of 6.5 years (95% CI, 6.4-6.9). Individuals experiencing FF (n=10/87) had a significantly lower absolute peak V ̇ $$ \dot{\mathrm{V}} $$ O2. In univariable models, peak V ̇ $$ \dot{\mathrm{V}} $$ O2 ratio scaled to body mass was not significantly associated with FF (HR, 0.91; P=0.111). However, peak V ̇ $$ \dot{\mathrm{V}} $$ O2 scaled by fat-free mass (HR, 0.90; P=0.020) or lean mass (HR, 0.90; P=0.017) was significantly and inversely associated with FF. These associations remained significant after adjusting for age, sex, and peak respiratory exchange ratio.

CONCLUSIONS

The association between peak V ̇ $$ \dot{\mathrm{V}} $$ O2 and FF is improved when scaled to measures of body composition. Applied clinically, a 1-unit increase in peak V ̇ $$ \dot{\mathrm{V}} $$ O2 scaled to fat-free mass or lean mass is associated with a ≈10% lower risk of FF.

Cardiac MRI Predictors of Arrhythmic Sudden Cardiac Events in Patients With Fontan Circulation

BACKGROUND

Among patients with congenital heart disease, those with single ventricles have the highest risk of early mortality. Sudden cardiac death is an important cause of death in this population. Understanding the risk factors for sudden cardiac events (SCE) in Fontan patients could improve prediction and prevention.

OBJECTIVES

The goal of this study was to determine the prevalence of SCE and risk factors for SCE in the Fontan population.

METHODS

The Fontan Outcomes Registry Using CMR Examinations (FORCE) is an international registry collecting clinical and imaging data on Fontan patients. SCE was defined as: 1) cardiac arrest from a shockable rhythm; 2) need for emergent cardioversion/defibrillation; or 3) documented sustained ventricular tachycardia. Univariate and multivariate Cox proportional hazards regression models estimated hazard ratios for predictors of SCE.

RESULTS

Our sample included 3,132 patients (41% female). The median age at first cardiac magnetic resonance was 14.6 years. SCE was experienced by 3.5% (n = 109) over a median follow-up time of 4.00 years. Of the 109 patients with SCE, 39 (36%) died. On multivariable analysis, NYHA functional class >II (HR: 4.91; P < 0.0001), history of protein-losing enteropathy/plastic bronchitis (HR: 2.37; P = 0.0082), single-ventricle end-diastolic volume index >104 mL/m2 (HR: 3.15; P < 0.0001), and ejection fraction <50% (HR: 1.73; P = 0.0437) were associated with SCE. Kaplan-Meier analysis demonstrated that in patients with none of the above risk factors, the 4-year freedom from SCE was 99.5%.

CONCLUSIONS

SCE occurred in 3.5% of the study population, and one-third of patients who experienced SCE died. Mild ventricular dysfunction and dilatation by cardiac magnetic resonance, NYHA functional class, and history of protein-losing enteropathy/plastic bronchitis were associated with SCE.

Transcatheter Interventions in Adults With Fontan Palliation

The Fontan circuit is associated with chronically elevated systemic venous pressures and decreased cardiac output, often leading to circuit failure. Managing Fontan circuit failure is complex and requires multiple therapeutic options. Transcatheter interventions have emerged as a reliable approach. They can alleviate obstructions and improve cyanosis by enhancing pulmonary blood flow and oxygen saturation. These procedures can also increase cardiac output and reduce systemic venous pressure, contributing to patient stabilization. In addition, they help mitigate volume overload and decrease the risk of bleeding during heart or combined heart and liver transplants. In recent years, percutaneous interventions have rapidly evolved and become a key therapeutic option for addressing various aspects of Fontan circuit failure. These interventions should be considered integral to the management strategy for this specific patient population.

Deterioration in Renal Function in Patients With a Fontan Circulation and Association With Mortality

Background

Renal dysfunction is a well-established risk factor in cardiovascular disease, but little is known about the prevalence and factors associated with deterioration in renal function in patients with a Fontan circulation.

Objectives

The purpose of the study was to investigate the course and factors associated with deterioration in renal function in patients with a Fontan circulation and its association with mortality.

Methods

This is a longitudinal study of patients with a Fontan circulation (n = 82), in which creatinine-based estimated glomerular filtration rate (eGFRcr) was measured over an 11-year time period. Cystatin C and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) levels were measured at baseline. Renal dysfunction was defined as an eGFR <90 ml/min/1.73 m2. Factors associated with annual change in eGFRcr were investigated with linear mixed-effect models and compared with data from a healthy Dutch cohort. The primary endpoint for the survival analyses was all-cause mortality. Associations between repeated eGFRcr levels and the primary endpoint were assessed using a joint model.

Results

The median age at baseline was 20 years (IQR: 14-27 years). Twelve percent of the cohort had renal dysfunction based on eGFRcr and 24% based on cystatin C-based eGFRcys. During follow-up, eGFRcr deteriorated on average by 1.36 ml/min/1.73 m2/year, which is faster than the healthy cohort. Higher baseline NT-proBNP z-scores were associated with a more rapid decline in eGFRcr. A larger decline in eGFRcr was associated with all-cause mortality.

Conclusions

Declines in eGFRcr in patients with Fontan circulation are more rapid than in healthy individuals. Higher baseline NT-proBNP z-scores are associated with a more rapid deterioration of eGFRcr, and eGFRcr deterioration is associated with mortality.

Psychosocial burden and quality of life of parents with children with univentricular hearts compared to ASD parents and parents of heart-healthy children

BACKGROUND

Patients with univentricular hearts can only be palliated by a staged surgical procedure that carries a high morbidity and mortality risk. The aim of this study was to examine the emotional demands, psychosocial burden, and quality of life of parents with children with univentricular hearts compared to parents of children with a simple heart defect, those with no heart defect and children with chronic diseases.

METHODS

An anonymous questionnaire was created to interview parents about their quality of life, stressors, needs, strategies for coping with illness, and partnership satisfaction.

RESULTS

73 families participated in the study. Parents of children with univentricular hearts experience a significantly higher psychosocial burden, limitations in daily life, and distress in family interactions, as well as greater emotional distress compared to the other study groups. When comparing the families of children with other chronic diseases (e.g. cystic fibrosis, chronic arthritis and diabetes), these differences remained significant.

CONCLUSION

The study confirms a higher psychosocial burden, restrictions in daily life and a lower quality of life of parents with children with univentricular hearts, compared to parents of children with simple heart defects and parents of heart-healthy children or those with other chronic diseases. Since this condition persists until adolescence and adulthood, the families are exposed to special challenges and stresses throughout their lives. This has yet to be adequately addressed in the management of these families.

Physical activity in the Fontan population: provider recommendations and patient actions

BACKGROUND

Emerging evidence suggests that routine physical activity may improve exercise capacity, long-term outcomes, and quality of life in individuals with Fontan circulation. Despite this, it is unclear how active these individuals are and what guidance they receive from medical providers regarding physical activity. The aim of this study was to survey Fontan patients on personal physical activity behaviours and their cardiologist-directed physical activity recommendations to set a baseline for future targeted efforts to improve this.

METHODS

An electronic survey assessing physical activity habits and cardiologist-directed guidance was developed in concert with content experts and patients/parents and shared via a social media campaign with Fontan patients and their families.

RESULTS

A total of 168 individuals completed the survey. The median age of respondents was 10 years, 51% identifying as male. Overall, 21% of respondents spend > 5 hours per week engaged in low-exertion activity and only 7% spend > 5 hours per week engaged in high-exertion activity. In all domains questioned, pre-adolescents reported higher participation rates than adolescents. Nearly half (43%) of respondents reported that they do not discuss activity recommendations with their cardiologist.

CONCLUSIONS

Despite increasing evidence over the last two decades demonstrating the benefit of exercise for individuals living with Fontan circulation, only a minority of patients report engaging in significant amounts of physical activity or discussing activity goals with their cardiologist. Specific, individualized, and actionable education needs to be provided to patients, families, and providers to promote and support regular physical activity in this patient population.

Central Venous Waveform Patterns in the Fontan Circulation Independently Contribute to the Prediction of Composite Survival

It is well appreciated that the Fontan circulation perturbs central venous hemodynamics, with elevated pressure being the clearest change associated with Fontan comorbidities, such as Fontan-associated liver disease (FALD) and protein-losing enteropathy (PLE). Our group has better quantity of these venous perturbations through single- and multi-location analyses of flow waveforms obtained from magnetic resonance imaging of Fontan patients. Here, we determine if such analyses, which yield principal components (PC) that describe flow features, are associated with Fontan survival. Patients with a Fontan circulation (N = 140) that underwent free-breathing and mechanically ventilated cardiac MRI were included in this study. Standard volumetric and functional hemodynamics, as well as flow analysis principal components, were subjected to univariate and bivariate Cox regression analyses to determine composite clinical outcome, including plastic bronchitis, PLE, and referral and receipt of transplant. Unsurprisingly, ventricular function measures of ejection fraction (EF; HR = 0.88, p < 0.0001), indexed end-systolic volume (ESVi; HR 1.02, p < 0.0001), and indexed end-diastolic volume (EDVi; HR = 1.02, p = 0.0007) were found as specific predictors of clinical events, with specificities uniformly > 0.75. Additionally a feature of IVC flow (PC2) indicating increased flow in systole was found as a highly sensitive predictor (HR = 0.851, p = 0.027, sensitivity 0.93). In bivariate prediction, combinations of ventricular function (EF, ESVi, EDVi) with this IVC flow feature yielded best overall prediction of composite outcome. This suggests that central venous waveform analysis relays additional information about Fontan patient survival and that coupling sensitive and specific measures in bivariate analysis is a useful approach for obtaining superior prediction of survival.

Functional Capacity Assessment in Adults After Fontan Palliation: A Cardiopulmonary Exercise Test-Invasive Exercise Hemodynamics Correlation Study

Although cardiopulmonary exercise testing (CPET) parameters have known prognostic value in adults after Fontan palliation, there are limited data correlating treadmill CPET with invasive exercise hemodynamics. Furthermore, the invasive hemodynamic underpinnings of exercise limitations have not been thoroughly investigated. This is a retrospective analysis of 55 adults (age ≥18 years) with prior Fontan palliation who underwent treadmill CPET before invasive exercise hemodynamic testing using a supine cycle protocol between November 2018 and April 2023. The median age was 32.2 (IQR 24.1; 37.2) years. The peak heart rate (HR) was 139.7 ± 28.1 beats per minute and the peak oxygen consumption (VO2) was 19.1 ± 5.7 ml/kg/min (47.4 ± 13.5% predicted). VO2/HR was directly related to exercise stroke volume index (r = 0.50, p = 0.0002), whereas no association was seen with exercise arterio-mixed venous O2 content difference (r = 0.14, p = 0.32). Peak HR was inversely related to exercise pulmonary artery (PA) pressures (r = -0.61, p <0.0001) and PA wedge pressures (PAWP) (r = -0.61, p <0.0001). Moreover, %predicted VO2 was inversely related to exercise PA pressures (r = -0.50, p <0.0001) and PAWP (r = -0.55, p <0.0001). Peak VO2 ≤19.1 ml/kg/min had a sensitivity of 81% and a specificity of 76% (area under the curve 0.82) for predicting a ΔPAWP/ΔQs ratio >2 mmHg/L/min and/or a ΔPA/ΔQp >3 mmHg/L/min, whereas a predicted peak VO2 ≤48% had a sensitivity of 74% and a specificity of 81% (area under the curve 0.79) for the same parameters. In summary, lower peak HR and peak VO2 were associated with higher exercise PAWP and PA pressure. Peak VO2 ≤48% predicted provided the optimal cutoff for predicting increased indexed exercise PAWP or PA pressures; therefore, low peak VO2 should alert clinicians of abnormal underlying hemodynamics.

Biomechanics and clinical implications of Fontan upsizing

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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