Enalapril in infants with single ventricle: results of a multicenter randomized trial

Cardiorenal Syndrome in Right Heart Failure Due to Pulmonary Arterial Hypertension-The Right Ventricle as a Therapeutic Target to Improve Renal Function

Cardiorenal syndrome (CRS) due to right ventricular (RV) failure is a disease entity emerging as a key indicator of morbidity and mortality. The multifactorial aspects of CRS and the left-right ventricular interdependence complicate the link between RV failure and renal function. RV failure has a direct pathophysiological link to renal dysfunction by leading to systemic venous congestion in certain circumstances and low cardiac output in other situations, both leading to impaired renal perfusion. Indeed, renal dysfunction is known to be an independent predictor of mortality in patients with pulmonary arterial hypertension (PAH) and RV failure. Thus, it is important to further understand the interaction between the RV and renal function. RV adaptation is critical to long-term survival in patients with PAH. The RV is also known for its remarkable capacity to recover once the aggravating factor is addressed or mitigated. However, less is known about the renal potential for recovery following the resolution of chronic RV failure. In this review, we provide an overview of the intricate relationship between RV dysfunction and the subsequent development of CRS, with a particular emphasis on PAH. Additionally, we summarize potential RV-targeted therapies and their potential beneficial impact on renal function.

Electrocardiogram-based deep learning to predict left ventricular systolic dysfunction in paediatric and adult congenital heart disease in the USA: a multicentre modelling study

BACKGROUND

Left ventricular systolic dysfunction (LVSD) is independently associated with cardiovascular events in patients with congenital heart disease. Although artificial intelligence-enhanced electrocardiogram (AI-ECG) analysis is predictive of LVSD in the general adult population, it has yet to be applied comprehensively across congenital heart disease lesions.

METHODS

We trained a convolutional neural network on paired ECG-echocardiograms (≤2 days apart) across the lifespan of a wide range of congenital heart disease lesions to detect left ventricular ejection fraction (LVEF) of 40% or less. Model performance was evaluated on single ECG-echocardiogram pairs per patient at Boston Children's Hospital (Boston, MA, USA) and externally at the Children's Hospital of Philadelphia (Philadelphia, PA, USA) using area under the receiver operating (AUROC) and precision-recall (AUPRC) curves.

FINDINGS

The training cohort comprised 124 265 ECG-echocardiogram pairs (49 158 patients; median age 10·5 years [IQR 3·5-16·8]; 3381 [2·7%] of 124 265 ECG-echocardiogram pairs with LVEF ≤40%). Test groups included internal testing (21 068 patients; median age 10·9 years [IQR 3·7-17·0]; 3381 [2·7%] of 124 265 ECG-echocardiogram pairs with LVEF ≤40%) and external validation (42 984 patients; median age 10·8 years [IQR 4·9-15·0]; 1313 [1·7%] of 76 400 ECG-echocardiogram pairs with LVEF ≤40%) cohorts. High model performance was achieved during internal testing (AUROC 0·95, AUPRC 0·33) and external validation (AUROC 0·96, AUPRC 0·25) for a wide range of congenital heart disease lesions. Patients with LVEF greater than 40% by echocardiogram who were deemed high risk by AI-ECG were more likely to have future dysfunction compared with low-risk patients (hazard ratio 12·1 [95% CI 8·4-17·3]; p<0·0001). High-risk patients by AI-ECG were at increased risk of mortality in the overall cohort and lesion-specific subgroups. Common salient features highlighted across congenital heart disaese lesions include precordial QRS complexes and T waves, with common high-risk ECG features including deep V2 S waves and lateral precordial T wave inversion. A case study on patients with ventricular pacing showed similar findings.

INTERPRETATION

Our externally validated algorithm shows promise in prediction of current and future LVSD in patients with congenital heart disease, providing a clinically impactful, inexpensive, and convenient cardiovascular health tool in this population.

FUNDING

Kostin Innovation Fund, Thrasher Research Fund Early Career Award, Boston Children's Hospital Electrophysiology Research Education Fund, National Institutes of Health, National Institute of Childhood Diseases and Human Development, and National Library of Medicine.

Impact of Serum Circulating Factors and PDE5 Inhibitor Therapy on Cardiomyocyte Metabolism in Single Ventricle Heart Disease

Background

While operative and perioperative care continues to improve for single ventricle congenital heart disease (SV), long-term morbidities and mortality remain high. Importantly, phosphodiesterase-5 inhibitor therapies (PDE5i) are increasingly used, however, little is known regarding the direct myocardial effects of PDE5i therapy in the SV population.

Objectives

Our group has previously demonstrated that the failing SV myocardium is characterized by increased PDE5 activity and impaired mitochondrial bioenergetics. Here we sought to determine whether serum circulating factors contribute to pathological metabolic remodeling in SV, and whether PDE5i therapy abrogates these changes.

Methods

Using an established in vitro model whereby primary cardiomyocytes are treated with patient sera +/- PDE5i, we assessed the impact of circulating factors on cardiomyocyte metabolism. Mass spectrometry-based lipidomics and metabolomics were performed to identify phospholipid and metabolite changes. Mitochondrial bioenergetics were assessed using the Seahorse Bioanalyzer and a stable isotope based mitochondrial enzyme activity assay. Relative mitochondrial copy number was quantified using RT-qPCR.

Results

Our data suggest that serum circulating factors contribute to fundamental changes in cardiomyocyte bioenergetics, including impaired mitochondrial function associated with decreased cardiolipin and other phospholipid species, increased reactive oxygen species (ROS) generation, and altered metabolite milieu. Treatment with PDE5i therapy was sufficient to abrogate a number of these metabolic changes, including a rescue of phosphatidylglycerol levels, a reduction in ROS, improved energy production, and normalization of several key metabolic intermediates.

Conclusions

Together, these data suggest PDE5i therapy has direct cardiomyocyte effects and contributes to beneficial cardiomyocyte metabolic remodeling in SV failure.

Right Ventricular Remodeling in Complex Congenital Heart Disease

In congenital heart diseases (CHDs) of moderate to great complexity involving the right ventricle (RV), the morphologic RV can be exposed to significant stressors across the lifespan, either in a biventricular circulation in a subpulmonary or subaortic position or as part of a univentricular circulation. These include pressure and/or volume overload, hypoxia, ischemia, and periprocedural surgical stress, leading to remodeling, maladaptation, dilation, hypertrophy, and dysfunction. In this review we examine the macroscopic remodeling of the RV in various forms of CHD and explore remodeling trajectories, along with the effects of surgeries and residual lesion repair, in tetralogy of Fallot, Ebstein anomaly, congenitally corrected transposition of the great arteries, transposition of the great arteries with atrial switch surgery, and single ventricle palliated by Fontan. In addition, the role of metabolism, genetic markers, and imaging criteria of RV remodeling are explored. Finally, the optimal timing for addressing residual lesions in CHD through surgery or percutaneous interventions is discussed, along with advanced heart failure management strategies and medical therapy aimed at preventing further RV dilation and/or systolic deterioration or promoting reverse remodeling.

Management of Pediatric Heart Failure

Heart failure (HF) in children is a complex syndrome with multiple diverse etiologies and both acute and chronic presentations. Chronic presentations can persist throughout childhood and adolescence, and require diligent management with ongoing reassessment to maximize survival and quality of life. Stages of HF are key to recognize as they guide both management and inform prognosis. In more severe cases, children can present with signs of low cardiac output and circulatory collapse with potential to transition either to a chronic HF stage or progress to a need for advanced HF therapies. Morbidity and mortality are high. Managing HF requires a multi-disciplinary approach that can adapt to the needs of the different phases of childhood and adolescence. Treatment can include medications, nutritional support, activity modifications, and potentially surgical intervention, pacemaker, respiratory or mechanical support, or even heart transplantation. Limited evidence exists for almost all medical therapies used in the management of HF in children and approaches are predominantly extrapolated from extensive adult experience. There are multiple maladaptive pathways in the failing heart; medications that modify these maladaptive pathways promote "reverse remodelling" of the myocardium and are key to the management, forming the basis for "guideline directed medical therapy". The purpose of this review is to summarize the current state of the art management of systolic HF in children.

Clinical and Hemodynamic Outcomes with Enalapril Orodispersible Minitablets in Young Children with Heart Failure Due to Congenital Heart Disease

Background: The angiotensin-converting enzyme inhibitor (ACEI) enalapril is often administered to infants and young children with heart failure (HF) in various dosing regimens and formulations not adapted for their age. Methods: This prospective, two-center, open-label 8-week study evaluated an age-appropriate formulation of orodispersible minitablets (ODMTs) of enalapril (0.25 mg and 1 mg) in children aged 0 to 6 years with HF due to congenital heart disease. An age/weight-based dosing schedule was followed. Measures of echocardiographic parameters, blood pressure, heart rate, modified Ross score, and biochemistry were obtained over the 8-week period. The following two groups were assessed: ACEI-naïve and ACEI-pretreated patients. Results: In total, 53 children (age range of 0.05 to 4.8 years) were enrolled and 29 were ACEI-naïve. The average enalapril dose was 0.098 mg/kg (0.06-0.17 mg/kg) in the naïve group and 0.15 mg/kg (0.07-0.3 mg/kg) in pretreated patients. After 8 weeks, the modified Ross score and left ventricular diastolic dimension (LVD) z-score showed a significant decrease in both groups (p < 0.005). During 8 weeks follow-up, there were no difference in the z-scores for the systolic blood pressure (p = 0.071) or heart rate (p = 0.146). Conclusions: Pediatric patients treated with ODMTs of enalapril for 8 weeks had favorable improvements in LVD and HF symptoms.

Evaluation and Management of Chronic Heart Failure in Children and Adolescents With Congenital Heart Disease: A Scientific Statement From the American Heart Association

With continued medical and surgical advancements, most children and adolescents with congenital heart disease are expected to survive to adulthood. Chronic heart failure is increasingly being recognized as a major contributor to ongoing morbidity and mortality in this population as it ages, and treatment strategies to prevent and treat heart failure in the pediatric population are needed. In addition to primary myocardial dysfunction, anatomical and pathophysiological abnormalities specific to various congenital heart disease lesions contribute to the development of heart failure and affect potential strategies commonly used to treat adult patients with heart failure. This scientific statement highlights the significant knowledge gaps in understanding the epidemiology, pathophysiology, staging, and outcomes of chronic heart failure in children and adolescents with congenital heart disease not amenable to catheter-based or surgical interventions. Efforts to harmonize the definitions, staging, follow-up, and approach to heart failure in children with congenital heart disease are critical to enable the conduct of rigorous scientific studies to advance our understanding of the actual burden of heart failure in this population and to allow the development of evidence-based heart failure therapies that can improve outcomes for this high-risk cohort.

Sacubitril-valsartan vs ACE/ARB in pediatric heart failure: A retrospective cohort study

BACKGROUND

The first angiotensin receptor/neprilysin inhibitor on the market, sacubitril-valsartan, has shown marked improvements in death and hospitalization for heart failure among adults, and is now approved for use in pediatric heart failure. While the ongoing PANORAMA-HF trial is evaluating the effectiveness of sacubitril-valsartan for pediatric patients with a failing systemic left ventricle, the enrollment criteria do not include the majority of pediatric heart failure patients. Additional studies are needed.

METHODS

Using the TriNetX database, we performed a propensity score matched, retrospective cohort study to assess the incidence of a composite of all-cause mortality or heart transplant within 1 year. The 519 patients who received sacubitril-valsartan were compared to 519 matched controls who received an angiotensin converting enzyme inhibitor (ACE) or angiotensin II receptor blocker (ARB).

RESULTS

There was no significant difference in the incidence of the composite outcome with sacubitril-valsartan over an ACE/ARB (13.3% vs 13.2%, p = 0.95), or among the components of mortality (5.0% vs 5.8%, p = 0.58) or heart transplantation (8.7% vs 7.5%, p = 0.50). Patients who were receiving full goal-directed medical therapy (14.4% vs 16.0%, p = 0.55) also showed no difference in the composite outcome. We observed a significantly increased incidence of hypotension (10% vs 5.2%, p = 0.006) and a trend toward reduced number of hospitalizations per year (mean (SD) 1.3 (4.4) vs 2.0 (9.1), p = 0.09).

CONCLUSIONS

Sacubitril-valsartan is not associated with a decrease in the composite of all-cause mortality or heart transplantation within 1 year. Future studies should evaluate the possible reduction in hospitalizations and optimal dosing to minimize hypotension.

The Pathophysiology(ies) of Heart Failure in Adults with Congenital Heart Disease

There is a growing, aging population of adults with congenital heart disease (CHD) with an increasing incidence of heart failure. Unquestioning extrapolation of widely applicable definitions of heart failure and guidelines for managing heart failure in adults with acquired heart failure to adults with CHD can be problematic. A nuanced and flexible application of clinical judgment founded on a deep understanding of underlying pathophysiology is needed to most effectively apply the many recent advances in managing acquired heart failure to the care of adults with CHD.

Treatment of hypoplastic left heart syndrome: a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

This meta-analysis aimed to consolidate existing data from randomised controlled trials on hypoplastic left heart syndrome.

METHODS

Hypoplastic left heart syndrome specific randomised controlled trials published between January 2005 and September 2021 in MEDLINE, EMBASE, and Cochrane databases were included. Regardless of clinical outcomes, we included all randomised controlled trials about hypoplastic left heart syndrome and categorised them according to their results. Two reviewers independently assessed for eligibility, relevance, and data extraction. The primary outcome was mortality after Norwood surgery. Study quality and heterogeneity were assessed. A random-effects model was used for analysis.

RESULTS

Of the 33 included randomised controlled trials, 21 compared right ventricle-to-pulmonary artery shunt and modified Blalock-Taussig-Thomas shunt during the Norwood procedure, and 12 regarded medication, surgical strategy, cardiopulmonary bypass tactics, and ICU management. Survival rates up to 1 year were superior in the right ventricle-to-pulmonary artery shunt group; this difference began to disappear at 3 years and remained unchanged until 6 years. The right ventricle-to-pulmonary artery shunt group had a significantly higher reintervention rate from the interstage to the 6-year follow-up period. Right ventricular function was better in the modified Blalock-Taussig-Thomas shunt group 1-3 years after the Norwood procedure, but its superiority diminished in the 6-year follow-up. Randomised controlled trials regarding medical treatment, surgical strategy during cardiopulmonary bypass, and ICU management yielded insignificant results.

CONCLUSIONS

Although right ventricle-to-pulmonary artery shunt appeared to be superior in the early period, the two shunts applied during the Norwood procedure demonstrated comparable long-term prognosis despite high reintervention rates in right ventricle-to-pulmonary artery shunt due to pulmonary artery stenosis. For medical/perioperative management of hypoplastic left heart syndrome, further randomised controlled trials are needed to deliver specific evidence-based recommendations.

School age and adolescent heart failure following the Norwood procedure

BACKGROUND

Heart failure results in significant morbidity and mortality for young children with hypoplastic left heart syndrome (HLHS) following the Norwood procedure. The trajectory in later childhood is not well described.

METHODS

We studied the outcome into adolescence of participants enrolled in the Single Ventricle Reconstruction trial who underwent the Fontan procedure or survived to 6 years without having undergone Fontan procedure. The primary outcome was heart failure events, defined as heart transplant listing or death attributable to heart failure. Symptomatic heart failure for participants surviving 10 or more years was also assessed utilizing the Pediatric Quality of Life Inventory (PedsQL).

RESULTS

Of the 345 participants who underwent a Fontan operation or survived to 6 years without Fontan, 25 (7.2%) had a heart failure event before the age of 12 years. Among these, 21 were listed for heart transplant, and 4 died from heart failure. Nineteen participants underwent heart transplant, all of whom survived to age 12 years. Factors associated with a heart failure event included longer Norwood hospital length of stay, aortic atresia, and no Fontan operation by age 6 years. Assessment of heart failure symptoms at 12 years of age revealed that 24 (12.2%) of 196 PedsQL respondents "often" or "almost always" had difficulty walking more than one block.

CONCLUSIONS

Heart failure events occur in over 5% of children with palliated HLHS between preschool age and adolescence. Outcomes for children listed for transplant are excellent. However, a substantial portion of palliated HLHS children have significant symptoms of heart failure at 12 years of age.

MicroRNA-34a-Dependent Attenuation of Angiogenesis in Right Ventricular Failure

BACKGROUND

The right ventricle (RV) is at risk in patients with complex congenital heart disease involving right-sided obstructive lesions. We have shown that capillary rarefaction occurs early in the pressure-loaded RV. Here we test the hypothesis that microRNA (miR)-34a, which is induced in RV hypertrophy and RV failure (RVF), blocks the hypoxia-inducible factor-1α-vascular endothelial growth factor (VEGF) axis, leading to the attenuated angiogenic response and increased susceptibility to RV failure.

METHODS AND RESULTS

Mice underwent pulmonary artery banding to induce RV hypertrophy and RVF. Capillary rarefaction occurred immediately. Although hypoxia-inducible factor-1α expression increased (0.12±0.01 versus 0.22±0.03, P=0.05), VEGF expression decreased (0.61±0.03 versus 0.22±0.05, P=0.01). miR-34a expression was most upregulated in fibroblasts (4-fold), but also in cardiomyocytes and endothelial cells (2-fold). Overexpression of miR-34a in endothelial cells increased cell senescence (10±3% versus 22±2%, P<0.05) by suppressing sirtulin 1 expression, and decreased tube formation by 50% via suppression of hypoxia-inducible factor-1α, VEGF A, VEGF B, and VEGF receptor 2. miR-34a was induced by stretch, transforming growth factor-β1, adrenergic stimulation, and hypoxia in cardiac fibroblasts and cardiomyocytes. In mice with RVF, locked nucleic acid-antimiR-34a improved RV shortening fraction and survival half-time and restored capillarity and VEGF expression. In children with congenital heart disease-related RVF, RV capillarity was decreased and miR-34a increased 5-fold.

CONCLUSIONS

In summary, miR-34a from fibroblasts, cardiomyocytes, and endothelial cells mediates capillary rarefaction by suppressing the hypoxia-inducible factor-1α-VEGF axis in RV hypertrophy/RVF, raising the potential for anti-miR-34a therapeutics in patients with at-risk RVs.

Stress Ulcer Prophylaxis Versus Placebo-A Blinded Pilot Randomized Controlled Trial to Evaluate the Safety of Two Strategies in Critically Ill Infants With Congenital Heart Disease

OBJECTIVES

The routine use of stress ulcer prophylaxis (SUP) in infants with congenital heart disease (CHD) in the cardiac ICU (CICU) is controversial. We aimed to conduct a pilot study to explore the feasibility of performing a subsequent larger trial to assess the safety and efficacy of withholding SUP in this population (NCT03667703).

DESIGN, SETTING, PATIENTS

Single-center, prospective, double-blinded, parallel group (SUP vs. placebo), pilot randomized controlled pilot trial (RCT) in infants with CHD admitted to the CICU and anticipated to require respiratory support for greater than 24 hours.

INTERVENTIONS

Patients were randomized 1:1 (stratified by age and admission type) to receive a histamine-2 receptor antagonist or placebo until respiratory support was discontinued, up to 14 days, or transfer from the CICU, if earlier.

MEASUREMENTS AND MAIN RESULTS

Feasibility was defined a priori by thresholds of screening rate, consent rate, timely drug allocation, and protocol adherence. The safety outcome was the rate of clinically significant upper gastrointestinal (UGI) bleeding. We screened 1,426 patients from February 2019 to March 2022; of 132 eligible patients, we gained informed consent in 70 (53%). Two patients did not require CICU admission after obtaining consent, and the remaining 68 patients were randomized to SUP (n = 34) or placebo (n = 34). Ten patients were withdrawn early, because of a change in eligibility (n = 3) or open-label SUP use (n = 7, 10%). Study procedures were completed in 58 patients (89% protocol adherence). All feasibility criteria were met. There were no clinically significant episodes of UGI bleeding during the pilot RCT. The percentage of patients with other nonserious adverse events did not differ between groups.

CONCLUSIONS

Withholding of SUP in infants with CHD admitted to the CICU was feasible. A larger multicenter RCT designed to confirm the safety of this intervention and its impact on incidence of UGI bleeding, gastrointestinal microbiome, and other clinical outcomes is warranted.

Outcomes of Children With Hypoplastic Left Heart Syndrome and Heart Failure on Medical Therapy

Background

Systemic right ventricle (RV) dysfunction is associated with lower transplant-free survival (TFS) in hypoplastic left heart syndrome (HLHS), but the likelihood of functional improvement and utility of heart failure (HF) medications is not understood.

Objectives

The authors aimed to describe TFS, HF medication use, and surgical interventions in HLHS patients with RV dysfunction with and without subsequent improvement in function.

Methods

The SickKids HF Database is a retrospective cohort that includes all pediatric HLHS patients with RV dysfunction lasting >30 days. We compared TFS, HF medications, and surgical interventions in HLHS patients with and without functional normalization.

Results

Of 99 patients with HLHS and RV dysfunction, 52% had normalized function for ≥30 days. TFS at 2 years after dysfunction onset was lower in those without normalization (14% vs 78%, P < 0.001). Patients without normalization were less likely to reach target dosing (TD) of HF medications (27% vs 47% on 1 medication at TD, P < 0.001) and undergo Fontan completion (7% vs 53%, P < 0.001). Clinical factors associated with improved TFS were normalization of function for ≥30 days, onset of dysfunction after bidirectional Glenn, and exposure to ACE inhibition.

Conclusions

Our cohort of HLHS patients with systemic RV dysfunction demonstrated a novel finding of improved TFS in those with functional normalization for ≥30 days. Achieving TD of HF medications was associated with improved outcomes. This may reflect patient stability and tolerance for HF medication more than its therapeutic effect, but it can help inform decisions to proceed with surgical palliation or list for transplant.

Captopril to Lisinopril Conversion in Pediatric Cardiothoracic Surgery Patients Less Than 7 Years of Age (RISE-7)

Hypertension after cardiothoracic surgery is common, often requiring pharmacologic management. The recommended first-line antihypertensives in pediatrics are angiotensin converting enzyme inhibitors. Captopril and enalapril are approved for infants and children; however, lisinopril is only approved for > 7 years of age. This study evaluated safety and efficacy of converting from captopril to lisinopril in patients utilizing a pre-defined conversion of 3 mg captopril to 1 mg lisinopril. This was a single center, retrospective study including patients less than 7 years of age admitted for cardiothoracic surgery who received both captopril and lisinopril from 01/01/2017 to 06/01/2022.The primary outcome was mean change in systolic blood pressure (SBP) from baseline for 72 h after conversion of captopril to lisinopril. A total of 99 patients were enrolled. There was a significant decrease in mean SBP (99.12 mmHg vs 94.86 mmHg; p = 0.007) with no difference in DBP (59.23 mmHg vs 61.95 mmHg; p = 0.07) after conversion to lisinopril. Of the 99 patients who were transitioned to lisinopril, 79 (80%) had controlled SBP, 20 (20%) remained hypertensive, 13 (13%) received an increase in their lisinopril dose, and 2 (2%) required an additional antihypertensive agent. There was a low overall rate of AKI (3%) and hyperkalemia (4%) respectively. This study demonstrates that utilizing lisinopril with a conversion rate of 3 mg of captopril to 1 mg of lisinopril was safe and effective for controlling hypertension in pediatric patients following cardiothoracic surgery.

Genetic and clinical variables act synergistically to impact neurodevelopmental outcomes in children with single ventricle heart disease

BACKGROUND

Recent large-scale sequencing efforts have shed light on the genetic contribution to the etiology of congenital heart defects (CHD); however, the relative impact of genetics on clinical outcomes remains less understood. Outcomes analyses using genetics are complicated by the intrinsic severity of the CHD lesion and interactions with conditionally dependent clinical variables.

METHODS

Bayesian Networks were applied to describe the intertwined relationships between clinical variables, demography, and genetics in a cohort of children with single ventricle CHD.

RESULTS

As isolated variables, a damaging genetic variant in a gene related to abnormal heart morphology and prolonged ventilator support following stage I palliative surgery increase the probability of having a low Mental Developmental Index (MDI) score at 14 months of age by 1.9- and 5.8-fold, respectively. However, in combination, these variables act synergistically to further increase the probability of a low MDI score by 10-fold. The absence of a damaging variant in a known syndromic CHD gene and a shorter post-operative ventilator support increase the probability of a normal MDI score 1.7- and 2.4-fold, respectively, but in combination increase the probability of a good outcome by 59-fold.

CONCLUSIONS

Our analyses suggest a modest genetic contribution to neurodevelopmental outcomes as isolated variables, similar to known clinical predictors. By contrast, genetic, demographic, and clinical variables interact synergistically to markedly impact clinical outcomes. These findings underscore the importance of capturing and quantifying the impact of damaging genomic variants in the context of multiple, conditionally dependent variables, such as pre- and post-operative factors, and demography.

Guiding future paediatric drug studies based on existing pharmacokinetic and efficacy data: Cardiovascular drugs as a proof of concept

INTRODUCTION

Off-label drug use in the paediatric population is common, and the lack of high-quality efficacy studies poses patients at risk for failing pharmacotherapy. Next to efficacy studies, pharmacokinetic (PK) studies are increasingly used to inform paediatric dose selection. As resources for paediatric trials are limited, we aimed to summarize existing PK and efficacy studies to identify knowledge gaps in available evidence supporting paediatric dosing recommendations, thereby taking paediatric cardiovascular drugs as proof of concept.

METHODS

For each cardiovascular drug, paediatric indication and prespecified age group, together comprising one record, the authorized state was assessed. Next, for off-label records, the highest level of evidence was scored. High-quality efficacy studies were defined as meta-analysis or randomized controlled trials. Other comparative research, noncomparative research or consensus-based expert opinions were considered low quality. The level of evidence for PK studies was scored per drug and per age group, but regardless of indication.

RESULTS

A total of 58 drugs included 417 records, of which 279 (67%) were off-label. Of all off-label records, the majority (81%) were not supported by high-quality efficacy studies, but for 140 of these records (62%) high-quality PK studies were available.

CONCLUSION

We demonstrated that for the majority of off-label cardiovascular drugs, only low-quality efficacy studies were available. However, high-quality PK studies were frequently available. Combining these PK data with extrapolation of efficacy data from adults may help to close the current information gap and prioritize the drugs for which clinical studies and safety data are urgently needed.

LCZ696 (sacubitril/valsartan) inhibits pulmonary hypertension induced right ventricular remodeling by targeting pyruvate dehydrogenase kinase 4

BACKGROUND

Right ventricular (RV) function is a major prognostic factor in patients with cardiopulmonary disease. Effective medical therapies are available for left heart failure, but they are usually less effective or even ineffective in right heart failure. Here, we tested the hypothesis that LCZ696 (sacubitril/valsartan) can attenuate pressure overload-induced RV remodeling by inhibiting pyruvate dehydrogenase kinase 4 (PDK4).

METHODS

Adult male C57 mice were subjected to transverse aortic constriction (TAC), pulmonary artery constriction (PAC), or sham surgery. Bioinformatics analysis was used to screen for common differentially expressed genes (DEGs) between TAC and PAC. Chemical compounds targeting DEGs were predicted by molecular docking analysis. Effects of LCZ696 on PAC-induced RV remodeling and the associated PDK4-related mechanisms were investigated.

RESULTS

We found 60 common DEGs between PAC and TAC, and Pdk4 was one of the downregulated DEGs. From 47 chemical compounds with potential cardiovascular activity and PDK4 protein binding ability, we selected LCZ696 to treat PAC-induced RV remodeling because of its high docking score for binding PDK4. Compared with vehicle-treated PAC mice, LCZ696-treated mice had significantly smaller RV wall thickness and RV diameters, less myocardial fibrosis, lower expression of PDK4 protein, and less phosphorylation of glycogen synthase kinase-3β (p-GSK3β). In PAC mice, overexpression of Pdk4 blocked the inhibitory effect of LCZ696 on RV remodeling, whereas conditional knockout of Pdk4 attenuated PAC-induced RV remodeling.

CONCLUSIONS

Pdk4 is a common therapeutic target for pressure overload-induced left ventricular and RV remodeling, and LCZ696 attenuates RV remodeling by downregulating Pdk4 and inhibiting PDK4/p-GSK3β signal.

Myocardial Fibrosis in Congenital Heart Disease and the Role of MRI

Progress in the field of congenital heart surgery over the last century can only be described as revolutionary. Recent improvements in patient outcomes have been achieved through refinements in perioperative care. In the current and future eras, the preservation and restoration of myocardial health, beginning with the monitoring of tissue remodeling, will be central to improving cardiac outcomes. Visualization and quantification of fibrotic myocardial remodeling is one of the greatest assets that cardiac MRI brings to the field of cardiology, and its clinical use within the field of congenital heart disease (CHD) has been an area of particular interest in the last few decades. This review summarizes the physical underpinnings of myocardial tissue characterization in CHD, with an emphasis on T1 parametric mapping and late gadolinium enhancement. It describes methods and suggestions for obtaining images, extracting quantitative and qualitative data, and interpreting the results for children and adults with CHD. The tissue characterization observed in different lesions is used to examine the causes and pathomechanisms of fibrotic remodeling in this population. Similarly, the clinical consequences of elevated imaging biomarkers of fibrosis on patient health and outcomes are explored. Keywords: Pediatrics, MR Imaging, Cardiac, Heart, Congenital, Tissue Characterization, Congenital Heart Disease, Cardiac MRI, Parametric Mapping, Fibrosis, Late Gadolinium Enhancement © RSNA, 2023.

The teammate trial: Study design and rationale tacrolimus and everolimus against tacrolimus and MMF in pediatric heart transplantation using the major adverse transplant event (MATE) score

BACKGROUND

Currently there are no immunosuppression regimens FDA-approved to prevent rejection in pediatric heart transplantation (HT). In recent years, everolimus (EVL) has emerged as a potential alternative to standard tacrolimus (TAC) as the primary immunosuppressant to prevent rejection that may also reduce the risk of cardiac allograft vasculopathy (CAV), chronic kidney disease (CKD) and cytomegalovirus (CMV) infection. However, the 2 regimens have never been compared head-to-head in a randomized trial. The study design and rationale are reviewed in light of the challenges inherent in rare disease research.

METHODS

The TEAMMATE trial (IND 127980) is the first multicenter randomized clinical trial (RCT) in pediatric HT. The primary purpose is to evaluate the safety and efficacy of EVL and low-dose TAC (LD-TAC) compared to standard-dose TAC and mycophenolate mofetil (MMF). Children aged <21 years at HT were randomized (1:1 ratio) at 6 months post-HT to either regimen, and followed for 30 months. Children with recurrent rejection, multi-organ transplant recipients, and those with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m² were excluded. The primary efficacy hypothesis is that, compared to TAC/MMF, EVL/LD-TAC is more effective in preventing 3 MATEs: acute cellular rejection (ACR), CKD and CAV. The primary safety hypothesis is that EVL/LD-TAC does not have a higher cumulative burden of 6 MATEs (antibody mediated rejection [AMR], infection, and post-transplant lymphoproliferative disorder [PTLD] in addition to the 3 above). The primary endpoint is the MATE score, a composite, ordinal surrogate endpoint reflecting the frequency and severity of MATEs that is validated against graft loss. The study had a target sample size of 210 patients across 25 sites and is powered to demonstrate superior efficacy of EVL/LD-TAC. Trial enrollment is complete and participant follow-up will be completed in 2023.

CONCLUSION

The TEAMMATE trial is the first multicenter RCT in pediatric HT. It is anticipated that the study will provide important information about the safety and efficacy of everolimus vs tacrolimus-based regimens and will provide valuable lessons into the design and conduct of future trials in pediatric HT.

Cardiac Transcriptome Remodeling and Impaired Bioenergetics in Single-Ventricle Congenital Heart Disease

The mechanisms responsible for heart failure in single-ventricle congenital heart disease are unknown. Using explanted heart tissue, we showed that failing single-ventricle hearts have dysregulated metabolic pathways, impaired mitochondrial function, decreased activity of carnitine palmitoyltransferase activity, and altered functioning of the tricarboxylic acid cycle. Interestingly, nonfailing single-ventricle hearts demonstrated an intermediate metabolic phenotype suggesting that they are vulnerable to development of heart failure in the future. Mitochondrial targeted therapies and treatments aimed at normalizing energy generation could represent a novel approach to the treatment or prevention of heart failure in this vulnerable group of patients.

Baseline Characteristics of Pediatric Patients With Heart Failure Due to Systemic Left Ventricular Systolic Dysfunction in the PANORAMA-HF Trial

BACKGROUND

Sacubitril/valsartan has been approved for the management of heart failure (HF) with reduced ejection fraction in adults. PANORAMA-HF trial (Prospective Trial to Assess the Angiotensin Receptor Blocker Neprilysin Inhibitor LCZ696 Versus Angiotensin-Converting Enzyme Inhibitor for the Medical Treatment of Pediatric HF) investigated its effects on clinical outcomes in pediatric patients with HF.

METHODS

PANORAMA-HF is a multicenter, Phase II/III study using an adaptive, seamless, 2-part design. The study aimed to evaluate the pharmacokinetics and pharmacodynamics of single doses of sacubitril/valsartan (Part 1), and the efficacy and safety of sacubitril/valsartan versus enalapril administered twice daily for 52 weeks (Part 2) in pediatric patients with HF due to left ventricular systolic dysfunction with biventricular heart physiology. An innovative trial design using a novel global rank assessment of severity was employed. For analysis, eligible patients were stratified into 3 age groups (Group 1, 6 to <18 years; Group 2a, 2 to <6 years; and Group 3a, 1 month to <2 years) and functional classification (New York Heart Association/Ross class I/II and III/IV).

RESULTS

We report the key demographic, baseline, and clinical characteristics of 375 pediatric patients randomized to receive the study medication. The mean age for patients in Groups 1, 2a, and 3a was 12.2, 3.2, and 1.3 years, respectively. About 70% of patients had a prior HF hospitalization, 85% had New York Heart Association/Ross class I/II HF, and ≈8% were angiotensin-converting enzyme inhibitor/angiotensin receptor blocker naïve.

CONCLUSIONS

Compared to other pediatric HF studies, PANORAMA-HF recruited a relatively homogeneous pediatric HF population across 3 age groups, enabling a more robust evaluation of pharmacokinetics/pharmacodynamics and efficacy/safety of sacubitril/valsartan. Most patients had mildly symptomatic HF at baseline.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02678312.

Prolonged Enteral Tube Feeding in Infants With a Functional Single Ventricle Is Associated With Adverse Outcomes After Fontan Completion

OBJECTIVES

To define the baseline characteristics of long-term tube-fed single ventricle patients, investigate associations between long-term enteral tube feeding and growth, and determine associations with long-term outcomes after Fontan procedure.

STUDY DESIGN

We performed a retrospective cohort study of patients in the Australia and New Zealand Fontan Registry undergoing treatment at the Royal Children's Hospital, the Children's Hospital at Westmead, Royal Melbourne Hospital, and Royal Prince Alfred Hospital from 1981-2018. Patients were defined as tube-fed (TF) or non-tube-fed (NTF) based on enteral tube feeding at age 90 days. Feeding groups were compared regarding BMI trajectory, BMI at last follow-up, and long-term incidence of severe Fontan failure.

RESULTS

Of 390 patients (56(14%) TF, 334(86%) NTF), TF was associated with right ventricular dominance, hypoplastic left heart syndrome, Norwood procedure, increased procedures prior to Fontan, extracardiac conduit Fontan, Fontan fenestration, and atrioventricular valve repair/replacement. TF patients were less likely to be in the higher compared with lowest 0-6 month BMI trajectory (P<0.01,P=0.03), had lower 6month weight-for-age z-scores (P<0.01) and length-for-age z-scores (P=0.01). TF were less likely to be overweight/obese at pediatric follow-up (HR=0.31,95%CI:0.12-0.80;P=0.02) and more likely to be underweight at adult follow-up ((HR=16.51; 5%CI:2.70-101.10;P<0.01).TF compared with NTF was associated with increased risk of severe Fontan failure (HR=4.13;95%CI=1.65,10.31;P<0.01).

CONCLUSIONS

Prolonged infant enteral tube feeding is an independent marker of poor growth and adverse clinical outcomes extending long-term post-Fontan procedure.

Feeding challenges in the newborn with congenital heart disease

PURPOSE OF REVIEW

Feeding challenges and growth failure are lifelong issues for infants with congenital heart disease. The purpose of this review is to summarize the literature on the topic from North America.

RECENT FINDINGS

Despite recognition of feeding challenges and ongoing national collaboration, >50% of infants with univentricular physiology continue to require supplemental tube feeds at the time of discharge from neonatal surgery. Preoperative feeding is now commonly used in prostaglandin dependent neonates with congenital heart disease. The value of a structured nutritional program with establishment of best practices in nutrition is well recognized in the current era. Despite implementation of these best practices, neonates undergoing cardiac surgery continue to struggle with weight gain prior to discharge. This suggests that there is more to growth than provision of adequate nutrition alone.

SUMMARY

The National Pediatric Cardiology Quality Improvement Collaborative continues to play a major role in optimizing nutrition in infants with congenital heart disease. This among other registries underscores the importance of collaboration in improving overall outcomes for children with congenital heart disease. Nurses should be encouraged to lead both clinical and research efforts to overcome feeding challenges encountered by these children.

Body Mass Index Trajectory and Outcome Post Fontan Procedure

Background Patients with a single ventricle who experience early life growth failure suffer high morbidity and mortality in the perisurgical period. However, long-term implications of poor infant growth, as well as associations between body mass index (BMI) and outcome in adulthood, remain unclear. We aimed to model BMI trajectories of patients with a single ventricle undergoing a Fontan procedure to determine trajectory-based differences in baseline characteristics and long-term clinical outcomes. Methods and Results We performed a retrospective analysis of medical records from patients in the Australia and New Zealand Fontan Registry receiving treatment at the Royal Children's Hospital, The Children's Hospital at Westmead, Royal Melbourne Hospital, and Royal Prince Alfred Hospital from 1981 to 2018. BMI trajectories were modeled in 496 patients using latent class growth analysis from 0 to 6 months, 6 to 60 months, and 5 to 16 years. Trajectories were compared regarding long-term incidence of severe Fontan failure (defined as mortality, heart transplantation, Fontan takedown, or New York Heart Association class III/IV heart failure). Three trajectories were found for male and female subjects at each age group-lower, middle, higher. Subjects in the lower trajectory at 0 to 6 months were more likely to have an atriopulmonary Fontan and experienced increased mortality long term. No association was found between higher BMI trajectory, current BMI, and long-term outcome. Conclusions Poor growth in early life correlates with increased long-term severe Fontan failure. Delineation of distinct BMI trajectories can be used in larger and older cohorts to find optimal BMI targets for patient outcome.

New insights on growth trajectory in infants with complex congenital heart disease

PURPOSE

We aimed to describe the weight-for-age Z-score growth trajectory (WAZ-GT) of infants with complex congenital heart disease (cCHD) after neonatal cardiac surgery in the first 4 months of life and assess potential risk factors.

METHODS

We utilized data from a previously reported trial of the REACH telehealth home monitoring (NCT01941667) program which evaluated 178 infants with cCHD from 2012 to 2017. Over the first 4 months of life, weekly infant weights were converted to WAZ. WAZ-GT classes were identified using latent class growth modeling. Multinomial logistic regression models were used to examine the associations between potential risk factors and WAZ-GT classes.

RESULTS

Four distinct classes of WAZ-GT were identified: maintaining WAZ > 0, 14%; stable around WAZ = 0, 35%; partially recovered, 28%; never recovered, 23%. Compared with reference group "stable around WAZ=0," we identified clinical and sociodemographic determinants of class membership for the three remaining groups. "Maintaining WAZ > 0" had greater odds of having biventricular physiology, borderline appetite, and a parent with at least a college education. "Partially recovered" had greater odds of hospital length of stay>14 days and being a single child in the household. "Never recovered" had greater odds hospital length of stay >14 and > 30 days, tube feeding at discharge, and low appetite.

CONCLUSIONS

This study described distinct classes of WAZ-GT for infants with cCHD early in infancy and identified associated determinants.

PRACTICE IMPLICATIONS

Findings from this study can be used in the identification of infants at risk of poor WAZ-GT and in the design of interventions to target growth in this vulnerable patient population.

Current evidence for pharmacologic therapy following stage 1 palliation for single ventricle congenital heart disease

INTRODUCTION

Infants with single ventricle congenital heart disease are vulnerable to complications between stage 1 and stage 2 of palliation. Pharmaceutical treatment during this period is varied and often dependent on institutional practices as there is little evidence supporting a particular treatment path.

AREAS COVERED

This review focuses on medical management of patients following stage I palliation. We performed a scoping review of the current literature regarding angiotensin converting enzyme inhibitors and digoxin treatment in the interstage period. In addition, we discuss other medication classes frequently used in these patients.

EXPERT OPINION

Due to significant heterogeneity of anatomy, rarity of disease, and other confounding factors, there is limited evidence to support most commonly used medications within the interstage period. Digoxin is associated with improved mortality within the interstage period and should be considered; however, no large randomized controlled trial exists supporting its use. Prevention of thrombotic complication with aspirin is also associated with improved outcomes and should be considered unless a contraindication exists. The addition of other prescriptions in this patient population should be considered only after an evaluation of the risks and benefits of each medication, recognizing the burden and risk of polypharmacy in this fragile patient population.

Accelerated Cardiac Aging in Patients With Congenital Heart Disease

An increasing number of patients with congenital heart disease (CHD) survive into adulthood but develop long-term complications including heart failure (HF). Cellular senescence, classically defined as stable cell cycle arrest, is implicated in biological processes such as embryogenesis, wound healing, and aging. Senescent cells have a complex senescence-associated secretory phenotype (SASP), involving a range of pro-inflammatory factors with important paracrine and autocrine effects on cell and tissue biology. While senescence has been mainly considered as a cause of diseases in the adulthood, it may be also implicated in some of the poor outcomes seen in patients with complex CHD. We propose that patients with CHD suffer from multiple repeated stress from an early stage of the life, which wear out homeostatic mechanisms and cause premature cardiac aging, with this term referring to the time-related irreversible deterioration of the organ physiological functions and integrity. In this review article, we gathered evidence from the literature indicating that growing up with CHD leads to abnormal inflammatory response, loss of proteostasis, and precocious age in cardiac cells. Novel research on this topic may inspire new therapies preventing HF in adult CHD patients.

Medical Therapies for Heart Failure in Hypoplastic Left Heart Syndrome

Significant surgical and medical advances over the past several decades have resulted in a growing number of infants and children surviving with hypoplastic left heart syndrome (HLHS) and other congenital heart defects associated with a single systemic right ventricle (RV). However, cardiac dysfunction and ultimately heart failure (HF) remain the most common cause of death and indication for transplantation in this population. Moreover, while early recognition and treatment of single ventricle-related complications are essential to improving outcomes, there are no proven therapeutic strategies for single systemic RV HF in the pediatric population. Importantly, prototypical adult HF therapies have been relatively ineffective in mitigating the need for cardiac transplantation in HLHS, likely due to several unique attributes of the failing HLHS myocardium. Here, we discuss the most commonly used medical therapies for the treatment of HF symptoms in HLHS and other single systemic RV patients. Additionally, we provide an overview of potential novel therapies for systemic ventricular failure in the HLHS and related populations based on fundamental science, pre-clinical, clinical, and observational studies in the current literature.

iPSC model of congenital heart disease predicts disease outcome

In this issue of Cell Stem Cell, Xu et al. demonstrate that induced pluripotent stem cell-derived cardiomyocytes from patients with hypoplastic left heart syndrome exhibit mitochondrial dysfunction and can be used for disease modeling. In addition, they show the potential to predict future heart failure and develop therapies.

Therapeutic Approaches in Heart Failure with Preserved Ejection Fraction (HFpEF) in Children: Present and Future

For a long time, pediatric heart failure (HF) with preserved systolic function (HFpEF) has been noted in patients with cardiomyopathies and congenital heart disease. HFpEF is infrequently reported in children and instead of using the  HFpEF terminology the HF symptoms are attributed to diastolic dysfunction. Identifying HFpEF in children is challenging because of heterogeneous etiologies and unknown pathophysiological mechanisms. Advances in echocardiography and cardiac magnetic resonance imaging techniques have further increased our understanding of HFpEF in children. However, the literature does not describe the incidence, etiology, clinical features, and treatment of HFpEF in children. At present, treatment of HFpEF in children is extrapolated from clinical trials in adults. There are significant differences between pediatric and adult HF with reduced ejection fraction, supported by a lack of adequate response to adult HF therapies. Evidence-based clinical trials in children are still not available because of the difficulty of conducting trials with a limited number of pediatric patients with HF. The treatment of HFpEF in children is based upon the clinician's experience, and the majority of children receive off-level medications. There are significant differences between pediatric and adult HFpEF pharmacotherapies in many areas, including side-effect profiles, underlying pathophysiologies, the β-receptor physiology, and pharmacokinetics and pharmacodynamics. This review describes the present and future treatments for children with HFpEF compared with adults. This review also highlights the need to urgently test new therapies in children with HFpEF to demonstrate the safety and efficacy of drugs and devices with proven benefits in adults.

Design and methods for the training in exercise activities and motion for growth (TEAM 4 growth) trial: A randomized controlled trial

BACKGROUND

Growth is often impaired in infants with congenital heart disease. Poor growth has been associated with worse neurodevelopment, abnormal behavioral state, and longer time to hospital discharge. Nutritional interventions, drug therapy, and surgical palliation have varying degrees of success enhancing growth. Passive range of motion (PROM) improves somatic growth in preterm infants and is safe and feasible in infants with hypoplastic left heart syndrome (HLHS), after their first palliative surgery (Norwood procedure).

METHODS

This multicenter, Phase III randomized control trial of a 21-day PROM exercise or standard of care evaluates growth in infants with HLHS after the Norwood procedure. Growth (weight-, height- and head circumference-for-age z-scores) will be compared at 4 months of age or at the pre-superior cavopulmonary connection evaluation visit, whichever comes first. Secondary outcomes include neonatal neurobehavioral patterns, neurodevelopmental assessment, and bone mineral density. Eligibility include diagnosis of HLHS or other single right ventricle anomaly, birth at ≥37 weeks gestation and Norwood procedure at <30 days of age, and family consent. Infants with known chromosomal or recognizable phenotypic syndromes associated with growth failure, listed for transplant, or expected to be discharged within 14 days of screening are excluded.

CONCLUSIONS

The TEAM 4 Growth trial will make an important contribution to understanding the role of PROM on growth, neurobehavior, neurodevelopment, and BMD in infants with complex cardiac anomalies, who are at high risk for growth failure and developmental concerns.

Uncompensated mitochondrial oxidative stress underlies heart failure in an iPSC-derived model of congenital heart disease

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease with 30% mortality from heart failure (HF) in the first year of life, but the cause of early HF remains unknown. Induced pluripotent stem-cell-derived cardiomyocytes (iPSC-CM) from patients with HLHS showed that early HF is associated with increased apoptosis, mitochondrial respiration defects, and redox stress from abnormal mitochondrial permeability transition pore (mPTP) opening and failed antioxidant response. In contrast, iPSC-CM from patients without early HF showed normal respiration with elevated antioxidant response. Single-cell transcriptomics confirmed that early HF is associated with mitochondrial dysfunction accompanied with endoplasmic reticulum (ER) stress. These findings indicate that uncompensated oxidative stress underlies early HF in HLHS. Importantly, mitochondrial respiration defects, oxidative stress, and apoptosis were rescued by treatment with sildenafil to inhibit mPTP opening or TUDCA to suppress ER stress. Together these findings point to the potential use of patient iPSC-CM for modeling clinical heart failure and the development of therapeutics.

Loss of cardiac myosin light chain kinase contributes to contractile dysfunction in right ventricular pressure overload

Nearly 1 in every 100 children born have a congenital heart defect. Many of these defects primarily affect the right heart causing pressure overload of the right ventricle (RV). The RV maintains function by adapting to the increased pressure; however, many of these adaptations eventually lead to RV hypertrophy and failure. In this study, we aim to identify the cellular and molecular mechanisms of these adaptions. We utilized a surgical animal model of pulmonary artery banding (PAB) in juvenile rats that has been shown to accurately recapitulate the physiology of right ventricular pressure overload in young hearts. Using this model, we examined changes in cardiac myocyte protein expression as a result of pressure overload with mass spectrometry 4 weeks post-banding. We found pressure overload of the RV induced significant downregulation of cardiac myosin light chain kinase (cMLCK). Single myocyte calcium and contractility recordings showed impaired contraction and relaxation in PAB RV myocytes, consistent with the loss of cMLCK. In the PAB myocytes, calcium transients were of smaller amplitude and decayed at a slower rate compared to controls. We also identified miR-200c, which has been shown to regulate cMLCK expression, as upregulated in the RV in response to pressure overload. These results indicate the loss of cMLCK is a critical maladaptation of the RV to pressure overload and represents a novel target for therapeutic approaches to treat RV hypertrophy and failure associated with congenital heart defects.

Late Fontan Circulatory Failure. What Drives Systemic Venous Congestion and Low Cardiac Output in Adult Fontan Patients?

The Fontan circulation provides definite palliation for children born with a single anatomical or functional ventricle by diverting systemic venous blood directly to the pulmonary arteries, effectively rendering systemic venous return into portal vessels to the lung. Although this restores pulmonary blood flow and avoids the mixture of oxygenated and deoxygenated blood, it also results in elevated systemic venous pressures and low cardiac output. These are the two hallmarks of any Fontan circulation and the cause of Fontan circulatory failure later in life. We highlight the determinants of systemic venous return, its changed relationship with the pulmonary circulation, how it affects preload, and the changed role of the heart (myocardium, valves, and heart rate). By critically evaluating the components of the Fontan circulation, we hope to give some clues in how to optimize the Fontan circulation and avenues for future research.

Can Pediatric Heart Failure Therapy Be Improved? Yes It Can, But…

Given the heterogenous etiology of pediatric heart failure (pHF), evidence-based studies improving pHF are unlikely. A paradigm shift towards updated medicine-based evidence is therefore necessary. In view of the life expectancy of children, cardiac regeneration strategies are required. Therefore, age- and disease-related differences in myocardial (receptor) physiology require individualized precision medicine. First-line diuretic therapy, adopted from the treatment of adults with HF with no chance for recovery, should be questioned in the treatment of pHF with potential for recovery. Inadequate use of diuretics is a common reason for additional stimulation of the neurohumoral axis. Consecutive intravascular volume depletion led to an inadequate treatment with β-blocker and renin-angiotensin-aldosterone antagonists. Given the age-related catecholamine-driven cardiovascular (patho-) physiology, highly selective β1-blockers (bisoprolol) protect against β1-(noradrenaline)-related myocytic apoptosis and necrosis, but allow β2-receptor-mediated myocardial regeneration. Based on its high safety-efficacy profile with rarely seen adverse effects but easily monitorable efficacy by the surrogate of heart rate (reduction), bisoprolol is our first-line drug in infancy. Reduced heart rate economizes the heart and full body oxygen consumption and extends the diastolic filling and coronary perfusion time. Based on our many years of institutional experience, physicians should be encouraged to use β1-selected blockers in infants with dilated cardiomyopathy and hypoplastic left heart syndrome after stage-1 procedure, but also to treat ventricular septal defects with a significant left-to-right shunt. In summary, individualized pHF therapy is the prerequisite for a causal treatment to improve HF symptoms, but above all for the most functional regeneration possible.

Contemporary Provider Management Practices and Attitudes Toward Referral for Advanced Heart Failure Therapies in Fontan Patients Across North America

BACKGROUND

To date, no reports have described clinicians' management practices for patients with Fontan circulatory failure or their understanding of risk factors for mortality and transplant outcomes in these patients.

METHODS AND RESULTS

A cross-sectional survey of caregivers across North America was conducted from February to September 2020. Responses were compared by primary specialty (heart failure/transplant vs non-heart failure/transplant), years of experience (early, mid, and late career), and Fontan center volume (low, medium, and high). Of 400 responses, the majority were from general cardiologists (111, 28%) followed by heart failure/transplant specialists (93, 23%). Although most agreed that patients with Fontan physiology will have signs/symptoms of heart failure (369 [93%]) and eventuate in heart transplant (286 [72%]), many disagreed (180 [45%]) that routine evaluation by a transplant cardiologist is needed without symptoms. Transplant providers were more likely than non-transplant providers to suggest referral for manifestations of Fontan circulatory failure such as protein-losing enteropathy, plastic bronchitis, liver fibrosis/cirrhosis, and worsening valve regurgitation. Non-transplant providers were more likely to suggest that protein-losing enteropathy, plastic bronchitis, and Fontan-associated liver disease lead to inferior outcomes after transplantation. Early career and transplant providers more favorably viewed ventricular assist device use for Fontan patients failing traditional heart failure therapy (P < .05 for all).

CONCLUSIONS

There is significant variation in the management of Fontan patients, including heterogeneous timing of referral of such patients to the heart failure/transplant team, which may have implications for future outcomes.

Angiotensin-Converting Enzyme Inhibitors/Angiotensin Receptor Blockers: Anti-arrhythmic Drug for Arrhythmogenic Right Ventricular Cardiomyopathy

Background: Current treatment guidelines for arrhythmogenic right ventricular cardiomyopathy (ARVC) mainly emphasize on prevention of ventricular arrhythmic events. Despite the progressive nature of ARVC, therapeutic options focusing on decelerating disease progression are scarce.

Methods and Results: This retrospective observational cohort study included 311 patients [age, 39.1 ± 14.4 years; male, 233 (74.9%)] with a definite diagnosis of ARVC as determined by the 2010 Task Force Diagnostic Criteria. Among them, 113 patients (36.3%) received ACEI/ARB treatment. Disease progression was evaluated according to repeat transthoracic echocardiograms with a linear mixed model. Patients receiving ACEI/ARB treatment were associated with slower disease progression reflected by a gradual decrease in tricuspid annular plane systolic excursion than those not receiving ACEI/ARB treatment (0.37 vs. 0.61 mm per year decrease, P < 0.001) and slower dilation of right ventricular outflow tract (0.57 vs. 1.06 mm per year increased, P = 0.003). Cox proportional hazard regression models were used to evaluate the association between life-threatening ventricular tachycardia events and ACEI/ARB treatment. A reduced risk of life-threatening ventricular arrhythmia was associated with ACEI/ARB treatment compared to that without ACEI/ARB treatment (adjusted HR: 0.71, 95% CI: 0.52–0.96, P = 0.031).

Conclusions: ACEI/ARB treatment is associated with slower disease progression and lower risk of life-threatening ventricular arrhythmia in patients with ARVC. Delaying disease progression may pave way for reducing life-threatening ventricular arrhythmia risk.

Angiotensin-converting enzyme inhibition and pre-superior cavopulmonary connection haemodynamics in infants with single-ventricle physiology

INTRODUCTION

Preliminary animal and human data suggest that angiotensin-converting enzyme inhibition has a role in pulmonary vascular remodelling. We sought to assess the effect of ACEi versus placebo on pulmonary artery pressure and transpulmonary gradient amongst infants undergoing single-ventricle palliation.

MATERIALS AND METHODS

Using the publicly available Pediatric Heart Network Infant Single-Ventricle trial dataset, we compared mean PA pressure at pre-superior cavopulmonary connection catheterisation (primary outcome), transpulmonary gradient, pulmonary-to-systemic flow ratio, and post-SCPC oxygen saturation (secondary outcomes) in infants receiving enalapril versus placebo.

RESULTS

A total of 179 infants underwent pre-SCPC catheterisation, of which 85 (47%) received enalapril. There was no difference between the enalapril and placebo group in the primary and the secondary outcomes. Mean PA pressure in the enalapril group was 13.1 ± 2.9 compared to 13.7 ± 3.4 mmHg in the placebo group. The transpulmonary gradient was 6.7 ± 2.5 versus 6.9 ± 3.2 mmHg in the enalapril and placebo groups, respectively. The pulmonary-to-systemic flow ratio was 1.1 ± 0.5 in the enalapril group versus 1.0 ± 0.5 in the placebo group and the post-SCPC saturation was 83.1 ± 5.0% in the enalapril group versus 82.2 ± 5.3% in the placebo group. In the pre-specified subgroup analyses comparing enalapril and placebo according to ventricular morphology and shunt type, there was no difference in the primary and secondary outcomes.

CONCLUSION

ACEi did not impact mean pulmonary artery pressure or transpulmonary gradient amongst infants with single-ventricle physiology prior to SCPC palliation.

A word on netting of angiotensin-converting enzyme inhibitor therapy in hypoplastic left heart syndrome following stage-I

NPC-QIC Registry data showed that angiotensin-converting enzyme inhibitors were described in almost 38% for patients with single ventricle physiology after stage-I Norwood palliation. However, mortality and ventricular dysfunction or atrioventricular valve insufficiency seems to be not improved by oral application of angiotensin-converting enzyme inhibitors. The final conclusion was that despite limited evidence of benefit for patients with hypoplastic left heart syndrome, prescription of angiotensin-converting enzyme inhibitors during interstage is still common. Taking into account of the predominant cardiovascular regulation in newborns and young infants by circulating catecholamines, no real improvement is to be expected from angiotensin-converting enzyme inhibitor monotherapy. The goals of drug therapy after stage-I Norwood palliation in hypoplastic left heart syndrome are prevention of systemic right ventricle failure, balancing pulmonary and systemic blood flow, and reduction of oxygen consumption with regard to limitations of oxygen supply by the single ventricle, furthermore, avoiding harmful effects of endogenous catecholamine production in the long term on somatic and cognitive development. In this light of knowledge, we want to recommend the use of a long-acting and highly specific ß1-adrenoreceptor blocker for almost all patients after stage-I Norwood palliation and a combination with angiotensin-converting enzyme inhibitors only by indication after exclusion of potential side effects.

Poor Weight Recovery Between Stage 1 Palliation and Hospital Discharge for Infants with Single Ventricle Physiology: An Analysis of the National Pediatric Cardiology Quality Improvement Collaborative Phase II Dataset

OBJECTIVE

To investigate change in weight-for-age z-scores (WAZ) and risk factors for impaired weight gain between stage 1 palliation (S1P) for single ventricle physiology and discharge.

STUDY DESIGN

This was a secondary analysis of the National Pediatric Cardiology Quality Improvement Collaborative Phase II database. The primary outcome was change in WAZ between S1P and discharge. Risk factors were selected using multivariable mixed effects regression constructed by step-wise model selection, with adjustment for WAZ at S1P and a random effect for center.

RESULTS

Of 730 infants who were discharged after S1P, WAZ decreased in 98.6% (-1.5 ± 0.7). WAZ at discharge was <-1 but >-2 (at risk) in 40% and <-2 (failure to thrive) in 35% of participants. Males, higher WAZ at S1P, non-S1P procedures (mostly noncardiac), increased length of stay, necrotizing enterocolitis, and angiotensin-converting enzyme inhibitor use at discharge were associated with a greater decrease in WAZ. Preoperative enteral feeding and respiratory medications were associated with a lesser decrease in the WAZ.

CONCLUSIONS

Nearly all infants lose weight after S1P with little recovery by hospital discharge. At discharge, three-quarters of the infants in the cohort were at risk for impaired weight gain or had failure to thrive. Most risk factors associated with change in WAZ were unmodifiable or surrogates of disease severity. Novel interventions are needed to minimize the early catabolic effects and promote anabolic recovery after S1P.

Efficacy and safety of propranolol in infants with heart failure due to moderate-to-large ventricular septal defect (VSD-PHF study) - A prospective randomized trial

AIMS

The utility of beta-blocker therapy in infants with heart failure (HF) due to significant left-to-right shunt lesions is not known. The study aimed to assess the efficacy and safety of propranolol in infants with HF due to moderate-to-large ventricular septal defect (VSD).

METHODS

The prospective randomized trial included 80 infants with HF and moderate-to-large VSD, randomly allocated to receive either conventional therapy alone (n = 40) or propranolol plus conventional therapy (n = 40). The primary endpoint was a composite of all-cause mortality, hospitalization for HF and/or chest infection, and referral for surgery. The secondary clinical outcomes were the individual components of the composite endpoint. In addition, the patients were followed up to detect safety outcomes, for example, bronchospasm, bradyarrhythmia, and worsening HF symptoms.

RESULTS

The addition of propranolol therapy to the conventional medications did not result in significant improvement in the primary composite endpoint (32.50% vs. 52.50%; P = 0.07). There was a trend toward improvement, but the study is underpowered for this important question. However, propranolol therapy significantly decreased the risk of hospitalization (12.50% vs. 32.50%; P = 0.03) and worsening of Ross HF class (5.41% vs. 28.21%; P = 0.01) as compared to conventional therapy (estimated number needed to treat = 5). Propranolol did not result in any significant safety concerns in these infants except bronchospasm in an infant.

CONCLUSIONS

Propranolol therapy in infants with significant left-to-right shunt may prevent worsening in HF symptoms and hospitalization and is well tolerated. However, it does not reduce mortality or need for surgery.

Changes in Provider Prescribing Behavior for Infants with Single Ventricle Physiology After Evidence-Based Publications

BACKGROUND

The impact of published evidence on clinical practice has been understudied in pediatric cardiology.

OBJECTIVE

We sought to assess changes in prescribing behavior for angiotensin-converting enzyme inhibitor (ACEI) and digoxin at discharge after initial palliation of infants with single ventricle (SV) physiology following the publication of two large studies: The Pediatric Heart Network Infant Single Ventricle (PHN-ISV) trial showing no benefit with routine ACEI use and the National Pediatric Cardiology Quality Improvement Collaborative (NPC-QIC) analysis showing an association between digoxin and survival.

METHODS

ICD-9-10 codes identified SV infants from the Pediatric Health Information System (1/2004 to 1/2018) and charge codes identified medications at discharge. Generalized estimating equations implementing segmented logistic regressions modeled medication use, before and after (with a 3-month washout period) the relevant publication (ACEI 7/1/2010; digoxin 4/1/2016). A subgroup analysis was performed for hypoplastic left heart syndrome (HLHS).

RESULTS

ACEI use (37 centers, n = 4700) at discharge did not change over time during the pre-publication period. After publication of the PHN-ISV trial, ACEI use decreased (OR: 0.61, CI 0.44-0.84, p = 0.003). Digoxin use (43 centers, n = 4778) decreased by 1% monthly before publication. After the NPC-QIC publication, digoxin use increased (OR: 2.07, CI 1.05-4.08, p = 0.04) with an ongoing increase of 9% per month. Results were similar for the HLHS subgroup.

CONCLUSIONS

Prescribing behavior changed congruently after the publication of evidence-based studies, with decreased ACEI use and increased digoxin use at discharge following initial palliation of SV infants. Our findings suggest scientific findings were rapidly implemented into clinical practice.

Total vascular resistance increases during volume-unloading in asymptomatic single ventricle patients

OBJECTIVE

While the surgical stages of single ventricle (SV) palliation serve to separate pulmonary venous and systemic venous return, and to volume-unload the SV, staged palliation also results in transition from parallel to series circulation, increasing total vascular resistance. How this transition affects pressure loading of the SV is as yet unreported.

METHODS

We performed a retrospective chart review of Stage I, II, and III cardiac catheterization (CC) and echocardiographic data from 2001-2017 in all SV pts, with focus on systemic, pulmonary, and total vascular resistance (SVR, PVR, TVR respectively). Longitudinal analyses were performed with log-transformed variables. Effects of SVR-lowering medications were analyzed using Wilcoxon rank-sum testing.

RESULTS

There were 372 total patients who underwent CC at a Stage I (median age of 4.4 months, n=310), Stage II (median age 2.7 years, n = 244), and Stage III (median age 7.3 years, n = 113). Total volume loading decreases with progression to Stage III (P< 0.001). While PVR gradually increases from Stage II to Stage III, and SVR increases from Stage I to Stage III, TVR dramatically increases with progress towards series circulation. TVR was not affected by use of systemic vasodilator therapy. TVR, PVR, SVR, and CI did not correlate with indices of SV function at Stage III.

CONCLUSIONS

TVR steadily increases with an increasing contribution from SVR over progressive stages. TVR was not affected by systemic vasodilator agents. TVR did not correlate with echo-based indices of SV function. Further studies are needed to see if modulating TVR can improve exercise tolerance and outcomes.

Loop Diuretics in Infants with Heart Failure

Tremendous advances have been made in the last 5 decades in the surgical management of congenital heart disease (CHD). Most infants affected by clinically significant CHD are at risk for developing heart failure (HF). Adult HF management is mostly evidence-based and our knowledge in this field has expanded significantly in the past decade. However, data on management approaches for HF in infants are limited. The indications and implications for various medications and interventions in patients with HF secondary to CHD are an upcoming area of interest. It is critical that we expand our ability to prevent, detect, and manage HF in the pediatric population.

Current and Future Drug and Device Therapies for Pediatric Heart Failure Patients: Potential Lessons from Adult Trials

This review discusses the potential drug and device therapies for pediatric heart failure (HF) due to reduced systolic function. It is important to realize that most drugs that are used in pediatric HF are extrapolated from adult cardiology practices or consensus guidelines based on expert opinion rather than on evidence from controlled clinical trials. It is difficult to conclude whether the drugs that are well established in adult HF trials are also beneficial for children because of tremendous heterogeneity in the mechanism of HF in children and variations in the pharmacokinetics and pharmacodynamics of drugs from birth to adolescence. The lessons learned from adult trials can guide pediatric cardiologists to design clinical trials of the newer drugs that are in the pipeline to study their efficacy and safety in children with HF. This paper's focus is that the reader should specifically think through the pathophysiological mechanism of HF and the mode of action of drugs for the selection of appropriate pharmacotherapy. We review the drug and device trials in adults with HF to highlight the knowledge gap that exists in the pediatric HF population.