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Context: Although beta-blockers improve symptoms and survival in adults with heart failure, little is known about these medications in children and adolescents.Objective: To prospectively evaluate the effects of carvedilol in children and adolescents with symptomatic systemic ventricular systolic dysfunction.Design, Setting, and Participants: A multicenter, randomized, double-blind, placebo-controlled study of 161 children and adolescents with symptomatic systolic heart failure from 26 US centers. In addition to treatment with conventional heart failure medications, patients were assigned to receive placebo or carvedilol. Enrollment began in June 2000 and the last dose was given in May 2005 (each patient received medication for 8 months).Interventions: Patients were randomized in a 1:1:1 ratio to twice-daily dosing with placebo, low-dose carvedilol (0.2 mg/kg per dose if weight <62.5 kg or 12.5 mg per dose if weight > or =62.5 kg), or high-dose carvedilol (0.4 mg/kg per dose if weight <62.5 kg or 25 mg per dose if weight > or =62.5 kg) and were stratified according to whether each patient's systemic ventricle was a left ventricle or not.Main Outcome Measures: The primary outcome was a composite measure of heart failure outcomes in patients receiving carvedilol (low- and high-dose combined) vs placebo. Secondary efficacy variables included individual components of this composite, echocardiographic measures, and plasma b-type natriuretic peptide levels.Results: There was no statistically significant difference between groups for the composite end point based on the percentage of patients who improved, worsened, or were unchanged. Among 54 patients assigned to placebo, 30 improved (56%), 16 worsened (30%), and 8 were unchanged (15%); among 103 patients assigned to carvedilol, 58 improved (56%), 25 worsened (24%), and 20 were unchanged (19%). The rates of worsening were lower than expected. The odds ratio for worsened outcome for patients in the combined carvedilol group vs the placebo group was 0.79 (95% CI, 0.36-1.59; P = .47). A prespecified subgroup analysis noted significant interaction between treatment and ventricular morphology (P = .02), indicating a possible differential effect of treatment between patients with a systemic left ventricle (beneficial trend) and those whose systemic ventricle was not a left ventricle (nonbeneficial trend).Conclusions: These preliminary results suggest that carvedilol does not significantly improve clinical heart failure outcomes in children and adolescents with symptomatic systolic heart failure. However, given the lower than expected event rates, the trial may have been underpowered. There may be a differential effect of carvedilol in children and adolescents based on ventricular morphology.Trial Registration: clinicaltrials.gov Identifier: NCT00052026. [ABSTRACT FROM AUTHOR]

Background: With improved survival of adults with congenital heart disease (CHD) comes a need to understand the lifelong outcomes of this population. The aim of this paper is to describe the rationale and design of Congenital Heart Disease Project to Understand Lifelong Survivor Experience (CHD PULSE), a study to determine long-term medical, neurocognitive, and psychosocial outcomes among adults with a history of intervention for CHD and to identify factors associated with those outcomes., Methods: CHD PULSE is a cross-sectional survey conducted from September 2021 to April 2023 among adults aged 18 and older with a history of at least one intervention for CHD at one of 11 participating U.S. centers in the Pediatric Cardiac Care Consortium. Participants with CHD were asked to complete a 99-question survey on a variety of topics including: demographics, surgeries, health insurance, health care, heart doctors, general health, height and weight, education and work history, reproductive health (for women only), and COVID-19. To construct a control group for the study, siblings of survey respondents were invited to complete a similar survey. Descriptive statistics for demographics, disease severity, center, and method of survey completion were computed for participants and controls. Comparisons were made between participants and non-participants to assess for response bias and between CHD participants and sibling controls to assess for baseline differences., Results: Among the 14,322 eligible participants, there were 3133 respondents (21.9%) from 48 U.S. states with surveys returned for inclusion in the study. Sibling contact information was provided by 691 respondents, with surveys returned by 326 siblings (47.2%). The median age of participants was 32.8 years at time of survey completion, with an interquartile range of 27.2 years to 39.7 years and an overall range of 20.1 to 82.9 years. Participants were predominantly female (55.1%) and of non-Hispanic White race/ethnicity (87.1%). There were no differences between participants and non-participants regarding severity of CHD. Compared to non-participants, participants were more likely to be female, of older age, and be of non-Hispanic White race/ethnicity. Enrolled siblings were more likely to be female and slightly younger than participants., Conclusions: With surveys from 3133 participants from across the U.S., CHD PULSE is poised to provide keen insights into the lifelong journey of those living with CHD, extending beyond mere survival. These insights will offer opportunities for informing strategies to enhance and improve future outcomes for this population of patients., (Copyright © 2024. Published by Elsevier Inc.)

Background: The health-related quality of life (HRQOL) and cardiopulmonary exercise testing (CPET) performance of individuals with subclinical and early stage hypertrophic cardiomyopathy (HCM) have not been systematically studied. Improved understanding will inform the natural history of HCM and factors influencing well-being., Methods: VANISH trial (Valsartan for Attenuating Disease Evolution in Early Sarcomeric HCM) participants with early stage sarcomeric HCM (primary analysis cohort) and subclinical HCM (sarcomere variant without left ventricular hypertrophy comprising the exploratory cohort) who completed baseline and year 2 HRQOL assessment via the pediatric quality of life inventory and CPET were studied. Metrics correlating with baseline HRQOL and CPET performance were identified. The impact of valsartan treatment on these measures was analyzed in the early stage cohort., Results: Two hundred participants were included: 166 with early stage HCM (mean age, 23±10 years; 40% female; 97% White; and 92% New York Heart Association class I) and 34 subclinical sarcomere variant carriers (mean age, 16±5 years; 50% female; and 100% White). Baseline HRQOL was good in both cohorts, although slightly better in subclinical HCM (composite pediatric quality of life score 84.6±10.6 versus 90.2±9.8; P =0.005). Both cohorts demonstrated mildly reduced functional status (mean percent predicted peak oxygen uptake 73±16 versus 78±12 mL/kg per minute; P =0.18). Percent predicted peak oxygen uptake and peak oxygen pulse correlated with HRQOL. Valsartan improved physical HRQOL in early stage HCM (adjusted mean change in pediatric quality of life score +4.1 versus placebo; P =0.01) but did not significantly impact CPET performance., Conclusions: Functional capacity can be impaired in young, healthy people with early stage HCM, despite New York Heart Association class I status and good HRQOL. Peak oxygen uptake was similarly decreased in subclinical HCM despite normal left ventricular wall thickness and excellent HRQOL. Valsartan improved physical pediatric quality of life scores but did not significantly impact CPET performance. Further studies are needed for validation and to understand how to improve patient experience., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01912534., Competing Interests: Dr Day is involved in consulting for Lexicon Pharmaceuticals; is on the Data Monitoring Committee of Cytokinetics; and receives funding from Lexicon Pharmaceuticals and Bristol Myers Squibb. Dr Canter is a consultant for Bristol Myers Squibb and receives research support from Tenaya, Merck, and Novartis (none relevant). Dr Bach receives research support (institutional only) from MyoKardia, Bristol Myers Squibb, and Cytokinetics, outside of the submitted work. Dr Wheeler receives research support and in-kind support from MyoKardia Inc, a wholly owned subsidiary of Bristol Myers Squibb, and research support from Cytokinetics Inc and Novartis Inc, all outside of the submitted work. Dr Rossano is a consultant for AskBio, American Regent, Bayer, BioMarin, Bristol Myers Squibb, Enzyvant, and Merck. Dr Owens has been consulting for Bristol Myers Squibb, Cytokinetics, Pfizer, Tenaya, BioMarin, Lexicon, Lexeo, Edgewise, and Stealth Therapeutics and receives research support from Bristol Myers Squibb. Dr Mestroni receives research funding from Bristol Myers Squibb, Tenaya Therapeutics, Pfizer, BioMarin, Greenstone Bioscience, and Spark Therapeutics. Dr Taylor receives research funding from Bristol Myers Squibb, Tenaya Therapeutics, Rocket Pharmaceuticals, BioMarin, and Spark Therapeutics. Dr Patel receives a research grant from GE Healthcare. Dr Soslow is involved in unrelated consulting for Sarepta, Pfizer, Immunoforge, and WCG Imaging. Dr Claggett is involved in statistical consulting for Alnylam, Cardurion, Corvia, CVRx, Cytokinetics, Intellia, and Rocket. Dr Ho is a consultant for and receives research funding from Bristol Myers Squib, Pfizer, Cytokinetics, Tenaya, BioMarin, viz.AI, and Lexicon (none relevant). The other authors report no conflicts.

Background: There are conflicting data regarding the relationship between center volume and outcomes in pediatric heart transplantation. Previous studies have not fully accounted for differences in case mix, particularly in high-risk congenital heart disease (CHD) groups. We aimed to evaluate the relationship between center volume and outcomes using the Pediatric Heart Transplant Society (PHTS) Registry and explore how case mix may affect outcomes., Methods: A retrospective cohort study of all pediatric patients in the PHTS Registry who received a heart transplant from 2009 to 2018 was performed. Centers were divided into 5 groups based on average yearly transplant volume. The primary outcome was time to death or graft loss and outcomes were compared using Kaplan-Meier analysis., Results: There were 4583 cases among 55 centers included. There was no difference in time to death or graft loss by center volume in the entire cohort (p = .75), in patients with CHD (p = .79) or in patients with cardiomyopathy (p = .23). There was also no difference in time to death or graft loss by center size in patients undergoing transplant after Norwood, Glenn or Fontan (log rank p = .17, p = .31, and p = .10 respectively). There was a statistically significant difference in outcomes by center size in the positive crossmatch group (p < .0001), though no discernible pattern related to high or low center volume., Conclusions: Outcomes are similar among transplant centers of all sizes, including for high-risk patient groups with CHD. Future work is needed to understand how patient-specific risk factors may vary among centers of various sizes and whether this influences patient outcomes., (© 2024 Wiley Periodicals LLC.)

Background: Pediatric dilated cardiomyopathy often leads to death or cardiac transplantation. We sought to determine whether changes in left ventricular (LV) end-diastolic dimension (LVEDD), LV end-diastolic posterior wall thickness, and LV fractional shortening (LVFS) over time may help predict adverse outcomes., Methods and Results: We studied children up to 18 years old with dilated cardiomyopathy, enrolled between 1990 and 2009 in the Pediatric Cardiomyopathy Registry. Changes in LVFS, LVEDD, LV end-diastolic posterior wall thickness, and the LV end-diastolic posterior wall thickness:LVEDD ratio between baseline and follow-up echocardiograms acquired ≈1 year after diagnosis were determined for children who, at the 1-year follow-up had died, received a heart transplant, or were alive and transplant-free. Within 1 year after diagnosis, 40 (5.0%) of the 794 eligible children had died, 117 (14.7%) had undergone cardiac transplantation, and 585 (73.7%) had survived without transplantation. At diagnosis, survivors had higher median LVFS and lower median LVEDD Z scores. Median LVFS and LVEDD Z scores improved among survivors ( Z score changes of +2.6 and -1.1, respectively) but remained stable or worsened in the other 2 groups. The LV end-diastolic posterior wall thickness:LVEDD ratio increased in survivors only, suggesting beneficial reverse LV remodeling. The risk for death or cardiac transplantation up to 7 years later was lower when LVFS was improved at 1 year (hazard ratio [HR], 0.83; P =0.004) but was higher in those with progressive LV dilation (HR, 1.45; P <0.001)., Conclusions: Progressive deterioration in LV contractile function and increasing LV dilation are associated with both early and continuing mortality in children with dilated cardiomyopathy. Serial echocardiographic monitoring of these children is therefore indicated., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT00005391.

The aim of this study (CTOTC-09) was to assess the impact of "preformed" (at transplant) donor-specific anti-HLA antibody (DSA) and first year newly detected DSA (ndDSA) on allograft function at 3 years after pediatric heart transplantation (PHTx). We enrolled children listed at 9 North American centers. The primary end point was pulmonary capillary wedge pressure (PCWP) at 3 years posttransplant. Of 407 enrolled subjects, 370 achieved PHTx (mean age, 7.7 years; 57% male). Pre-PHTx sensitization status was nonsensitized (n = 163, 44%), sensitized/no DSA (n = 115, 31%), sensitized/DSA (n = 87, 24%), and insufficient DSA data (n = 5, 1%); 131 (35%) subjects developed ndDSA. Subjects with any DSA had comparable PCWP at 3 years to those with no DSA. There were also no significant differences overall between the 2 groups for other invasive hemodynamic measurements, systolic graft function by echocardiography, and serum brain natriuretic peptide concentration. However, in the multivariable analysis, persistent first-year DSA was a risk factor for 3-year abnormal graft function. Graft and patient survival did not differ between groups. In summary, overall, DSA status was not associated with worse allograft function or inferior patient and graft survival at 3 years, but persistent first-year DSA was a risk factor for late graft dysfunction., Competing Interests: Disclosure The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation., (Copyright © 2023 American Society of Transplantation & American Society of Transplant Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Myocardial fibrosis, as diagnosed on cardiac magnetic resonance imaging (cMRI) by late gadolinium enhancement (LGE), is associated with adverse outcomes in adults with hypertrophic cardiomyopathy (HCM), but its prevalence and magnitude in children with HCM have not been established. We investigated: (1) the prevalence and extent of myocardial fibrosis as detected by LGE cMRI; (2) the agreement between echocardiographic and cMRI measurements of cardiac structure; and (3) whether serum concentrations of N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) and cardiac troponin-T are associated with cMRI measurements., Methods: A cross-section of children with HCM from 9 tertiary-care pediatric heart centers in the U.S. and Canada were enrolled in this prospective NHLBI study of cardiac biomarkers in pediatric cardiomyopathy (ClinicalTrials.gov Identifier: NCT01873976). The median age of the 67 participants was 13.8 years (range 1-18 years). Core laboratories analyzed echocardiographic and cMRI measurements, and serum biomarker concentrations., Results: In 52 children with non-obstructive HCM undergoing cMRI, overall low levels of myocardial fibrosis with LGE >2% of left ventricular (LV) mass were detected in 37 (71%) (median %LGE, 9.0%; IQR: 6.0%, 13.0%; range, 0% to 57%). Echocardiographic and cMRI measurements of LV dimensions, LV mass, and interventricular septal thickness showed good agreement using the Bland-Altman method. NT-proBNP concentrations were strongly and positively associated with LV mass and interventricular septal thickness (P < .001), but not LGE., Conclusions: Low levels of myocardial fibrosis are common in pediatric patients with HCM seen at referral centers. Longitudinal studies of myocardial fibrosis and serum biomarkers are warranted to determine their predictive value for adverse outcomes in pediatric patients with HCM., (Copyright © 2023 Elsevier Inc. All rights reserved.)

This scientific statement from the American Heart Association focuses on treatment strategies and modalities for cardiomyopathy (heart muscle disease) in children and serves as a companion scientific statement for the recent statement on the classification and diagnosis of cardiomyopathy in children. We propose that the foundation of treatment of pediatric cardiomyopathies is based on these principles applied as personalized therapy for children with cardiomyopathy: (1) identification of the specific cardiac pathophysiology; (2) determination of the root cause of the cardiomyopathy so that, if applicable, cause-specific treatment can occur (precision medicine); and (3) application of therapies based on the associated clinical milieu of the patient. These clinical milieus include patients at risk for developing cardiomyopathy (cardiomyopathy phenotype negative), asymptomatic patients with cardiomyopathy (phenotype positive), patients with symptomatic cardiomyopathy, and patients with end-stage cardiomyopathy. This scientific statement focuses primarily on the most frequent phenotypes, dilated and hypertrophic, that occur in children. Other less frequent cardiomyopathies, including left ventricular noncompaction, restrictive cardiomyopathy, and arrhythmogenic cardiomyopathy, are discussed in less detail. Suggestions are based on previous clinical and investigational experience, extrapolating therapies for cardiomyopathies in adults to children and noting the problems and challenges that have arisen in this experience. These likely underscore the increasingly apparent differences in pathogenesis and even pathophysiology in childhood cardiomyopathies compared with adult disease. These differences will likely affect the utility of some adult therapy strategies. Therefore, special emphasis has been placed on cause-specific therapies in children for prevention and attenuation of their cardiomyopathy in addition to symptomatic treatments. Current investigational strategies and treatments not in wide clinical practice, including future direction for investigational management strategies, trial designs, and collaborative networks, are also discussed because they have the potential to further refine and improve the health and outcomes of children with cardiomyopathy in the future.

Human leukocyte antigen (HLA) molecular mismatch is a powerful biomarker of rejection. Few studies have explored its use in assessing rejection risk in heart transplant recipients. We tested the hypothesis that a combination of HLA Epitope Mismatch Algorithm (HLA-EMMA) and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE-II) algorithms can improve risk stratification of pediatric heart transplant recipients. Class I and II HLA genotyping were performed by next-generation sequencing on 274 recipient/donor pairs enrolled in the Clinical Trials in Organ Transplantation in Children (CTOTC). Using high-resolution genotypes, we performed HLA molecular mismatch analysis with HLA-EMMA and PIRCHE-II, and correlated these findings with clinical outcomes. Patients without pre-formed donor specific antibody (DSA) (n=100) were used for correlations with post-transplant DSA and antibody mediated rejection (ABMR). Risk cut-offs were determined for DSA and ABMR using both algorithms. HLA-EMMA cut-offs alone predict the risk of DSA and ABMR; however, if used in combination with PIRCHE-II, the population could be further stratified into low-, intermediate-, and high-risk groups. The combination of HLA-EMMA and PIRCHE-II enables more granular immunological risk stratification. Intermediate-risk cases, like low-risk cases, are at a lower risk of DSA and ABMR. This new way of risk evaluation may facilitate individualized immunosuppression and surveillance., Competing Interests: M. Niemann works for PIRCHE AG, which develops and operates the PIRCHE web service. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The reviewer MM declared a past co-authorship with the author MN to the handling editor., (Copyright © 2023 Ellison, Mangiola, Marrari, Bentlejewski, Sadowski, Zern, Kramer, Heidt, Niemann, Xu, Dipchand, Mahle, Rossano, Canter, Singh, Zuckerman, Hsu, Feingold, Webber and Zeevi.)

Background: Emerging evidence suggests that pediatric and adult dilated cardiomyopathy (DCM) represent distinct diseases. Few diagnostic tools exist for pediatric cardiologists to assess clinical status and prognosis. We hypothesized that pediatric DCM would have a unique biomarker profile compared to adult DCM and controls., Methods: We utilized a DNA aptamer array (SOMAScan) to compare biomarker profiles between pediatric and adult DCM. We simultaneously measured 1310 plasma proteins and peptides from 39 healthy children (mean age 3 years, interquartile range (IQR) 1-14), 39 ambulatory subjects with pediatric DCM (mean age 2.7 years, IQR 1-13), and 40 ambulatory adults with DCM (mean age 53 years, IQR 46-63)., Results: Pediatric and adult DCM patients displayed distinct biomarker profiles, despite similar clinical characteristics. We identified 20 plasma peptides and proteins that were increased in pediatric DCM compared to age- and sex-matched controls. Unbiased multidimensionality reduction analysis suggested previously unrecognized heterogeneity among pediatric DCM subjects. Biomarker profile analysis identified four subgroups of pediatric DCM with distinguishing clinical characteristics., Conclusions: These findings support the emerging concept that pediatric and adult DCM are distinct disease entities, signify the need to develop pediatric-specific biomarkers for disease prognostication, and challenge the paradigm that pediatric DCM should be viewed as a single disease., Impact: Pediatric and adult DCM patients displayed distinct biomarker profiles, despite similar clinical characteristics and outcomes. Our findings suggest that pediatric DCM may be a heterogeneous disease with various sub-phenotypes, including differing biomarker profiles and clinical findings. These data provide prerequisite information for future prospective studies that validate the identified pediatric DCM biomarkers, address their diagnostic accuracy and prognostic significance, and explore the full extent of heterogeneity amongst pediatric DCM patients., (© 2021. The Author(s), under exclusive licence to the International Pediatric Research Foundation, Inc.)

To understand the genetic contribution to primary pediatric cardiomyopathy, we performed exome sequencing in a large cohort of 528 children with cardiomyopathy. Using clinical interpretation guidelines and targeting genes implicated in cardiomyopathy, we identified a genetic cause in 32% of affected individuals. Cardiomyopathy sub-phenotypes differed by ancestry, age at diagnosis, and family history. Infants < 1 year were less likely to have a molecular diagnosis (p < 0.001). Using a discovery set of 1,703 candidate genes and informatic tools, we identified rare and damaging variants in 56% of affected individuals. We see an excess burden of damaging variants in affected individuals as compared to two independent control sets, 1000 Genomes Project (p < 0.001) and SPARK parental controls (p < 1 × 10 -16 ). Cardiomyopathy variant burden remained enriched when stratified by ancestry, variant type, and sub-phenotype, emphasizing the importance of understanding the contribution of these factors to genetic architecture. Enrichment in this discovery candidate gene set suggests multigenic mechanisms underlie sub-phenotype-specific causes and presentations of cardiomyopathy. These results identify important information about the genetic architecture of pediatric cardiomyopathy and support recommendations for clinical genetic testing in children while illustrating differences in genetic architecture by age, ancestry, and sub-phenotype and providing rationale for larger studies to investigate multigenic contributions., Competing Interests: Declaration of interests J.W.R. is a consultant for Amgen, Bayer, Novartis, and Abiomed. W.K.C. is on the scientific advisory board for the Regeneron Genetics Center. S.E.L. is a consultant for Tenaya Therapeutics and Bayer and on an advisory board for Myokardia., (Copyright © 2021 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Background: Fontan-associated liver disease (FALD) uniformly affects patients with long-term Fontan physiology. The effect of isolated heart transplant (HT) on the course of FALD post-HT is not well understood., Methods: We evaluated serial liver imaging pre- and post-HT to assess liver changes over time in a single-center retrospective analysis of Fontan HT recipients who had pre- and ≥1-year post-HT liver imaging. Available patient demographic and clinical data were reviewed, including available liver biopsy results., Results: Serial liver imaging was available in 19 patients with a median age at HT of 12 years (range 3-23), the median age from Fontan to HT of 5.7 years (range 0.8-16), and the median time from imaging to follow up of 27 months (range 12-136 months). Pre-HT liver imaging was classified as follows: normal (n=1), congested (n=9), fibrotic (n=7), and cirrhotic (n=2). The majority of transplanted patients (15/19) had improvement in their post-HT liver imaging, including 13 patients with initially abnormal imaging pre-HT having normal liver imaging at follow-up. One patient had persistent cirrhosis at 26-month follow-up, one patient had unchanged fibrosis at 18-month follow-up, and one patient progressed from fibrosis pre-HT to cirrhosis post-HT at 136 months. No patients had overt isolated liver failure during pre- or post-HT follow-up. Liver biopsy did not consistently correlate with imaging findings., Conclusions: Post-HT liver imaging evaluation in Fontan patients reveals heterogeneous liver outcomes. These results not only provide evidence for the improvement of FALD post-HT but also show the need for serial liver imaging follow-up post-HT., (© 2021 Wiley Periodicals LLC.)

Background Pediatric cardiomyopathy is a genetically heterogeneous disease with substantial morbidity and mortality. Current guidelines recommend genetic testing in children with hypertrophic, dilated, or restrictive cardiomyopathy, but practice variations exist. Robust data on clinical testing practices and diagnostic yield in children are lacking. This study aimed to identify the genetic causes of cardiomyopathy in children and to investigate clinical genetic testing practices. Methods and Results Children with familial or idiopathic cardiomyopathy were enrolled from 14 institutions in North America. Probands underwent exome sequencing. Rare sequence variants in 37 known cardiomyopathy genes were assessed for pathogenicity using consensus clinical interpretation guidelines. Of the 152 enrolled probands, 41% had a family history of cardiomyopathy. Of 81 (53%) who had undergone clinical genetic testing for cardiomyopathy before enrollment, 39 (48%) had a positive result. Genetic testing rates varied from 0% to 97% between sites. A positive family history and hypertrophic cardiomyopathy subtype were associated with increased likelihood of genetic testing ( P =0.005 and P =0.03, respectively). A molecular cause was identified in an additional 21% of the 63 children who did not undergo clinical testing, with positive results identified in both familial and idiopathic cases and across all phenotypic subtypes. Conclusions A definitive molecular genetic diagnosis can be made in a substantial proportion of children for whom the cause and heritable nature of their cardiomyopathy was previously unknown. Practice variations in genetic testing are great and should be reduced. Improvements can be made in comprehensive cardiac screening and predictive genetic testing in first-degree relatives. Overall, our results support use of routine genetic testing in cases of both familial and idiopathic cardiomyopathy. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01873963.

Background: The first year after heart transplantation (HT) has the highest risk of mortality. We aim to derive and validate a recipient risk prediction tool for early mortality after pediatric HT., Methods: The International Society for Heart and Lung Transplantation (ISHLT) registry was used to identify patients (≤18 y) who underwent primary HT during January 2000-December 2014. Independent predictors of 1-year mortality were identified based on recipient characteristics at HT. Risk scores were assigned based on the magnitude of relative odds of 1-year mortality. The predictive capability of the ISHLT registry derived recipient risk score was externally validated using the Scientific Registry of Transplant Recipients registry data from 2015 to 2017 to ensure a cohort of patients completely exclusive from the derivation cohort., Results: A total of 5045 eligible patients were included in the analysis. The 20-point risk scoring system incorporated 8 recipient variables, including age at HT, diagnosis, pre-HT ventilator use, extracorporeal membrane oxygenation, inhaled nitric oxide use, infection, estimated glomerular filtration rate, and serum bilirubin. Compared with low-risk score group, high-risk group had 7-fold increased risk of 1-year mortality (hazard ratio 7.4; 95% CI [5.2-9.1]; P < 0.001). The C-statistics (0.77) and Hosmer-Lemeshow goodness of fit (0.9) for recipient risk score using derivation cohort from ISHLT registry performed well and was similar to the internal and external validation cohort (C-statistics 0.75, 0.78 and Hosmer-Lemeshow goodness of fit P = 0.4, 0.3, respectively)., Conclusions: This study derived and externally validated a simple risk predictive model based on recipient characteristics at HT that has good prediction characteristics for 1-year post-HT mortality. This model may help clinicians identify candidates who are at a higher risk for post-HT mortality and may optimize organ sharing.

The frequency, indications, and outcomes for readmission following pediatric heart transplantation are poorly characterized. A better understanding of this phenomenon will help guide strategies to address the causes of readmission. Data from the Clinical Trials in Organ Transplantation for Children (CTOTC-04) multi-institutional collaborative study were utilized to determine incidence of, and risk factors for, hospital readmission within 30 days and 1 year from initial hospital discharge. Among 240 transplants at 8 centers, 227 subjects were discharged and had follow-up. 129 subjects (56.8%) were readmitted within one year; 71 had two or more readmissions. The 30-day and 1-year freedom from readmission were 70.5% (CI: 64.1%, 76.0%) and 42.2% (CI: 35.7%, 48.7%), respectively. The most common indications for readmissions were infection followed by rejection and fever without confirmed infection, accounting for 25.0%, 10.6%, and 6.2% of readmissions, respectively. Factors independently associated with increased risk of first readmission within 1 year (Cox proportional hazard model) were as follows: transplant in infancy (P = .05), longer transplant hospitalization (P = .04), lower UNOS urgency status (2/IB vs 1A) at transplant (P = .04), and Hispanic ethnicity (P = .05). Hospital readmission occurs frequently in the first year following discharge after heart transplantation with highest risk in the first 30 days. Infection is more common than rejection as cause for readmission, with death during readmission being rare. A number of patient factors are associated with higher risk of readmission. A fuller understanding of these risk factors may help tailor strategies to reduce unnecessary hospital readmission., (© 2019 Wiley Periodicals, Inc.)

Background: Immunosuppression strategies have changed over time in pediatric heart transplantation. Thus, comorbidity profiles may have evolved. Clinical Trials in Organ Transplantation in Children-04 is a multicenter, prospective, cohort study assessing the impact of pre-transplant sensitization on outcomes after pediatric heart transplantation. This sub-study reports 1-year outcomes among recipients without pre-transplant donor-specific antibodies (DSAs)., Methods: We recruited consecutive candidates (<21 years) at 8 centers. Sensitization status was determined by a core laboratory. Immunosuppression was standardized as follows: Thymoglobulin induction with tacrolimus and/or mycophenolate mofetil maintenance. Steroids were not used beyond 1 week. Rejection surveillance was by serial biopsy., Results: There were 240 transplants. Subjects for this sub-study (n = 186) were non-sensitized (n = 108) or had no DSAs (n = 78). Median age was 6 years, 48.4% were male, and 38.2% had congenital heart disease. Patient survival was 94.5% (95% confidence interval, 90.1-97.0%). Freedom from any type of rejection was 67.5%. Risk factors for rejection were older age at transplant and presence of non-DSAs pre-transplant. Freedom from infection requiring hospitalization/intravenous anti-microbials was 75.4%. Freedom from rehospitalization was 40.3%. New-onset diabetes mellitus and post-transplant lymphoproliferative disorder (PTLD) occurred in 1.6% and 1.1% of subjects, respectively. There was no decline in renal function over the first year. Corticosteroids were used in 14.5% at 1 year., Conclusions: Pediatric heart transplantation recipients without DSAs at transplant and managed with a steroid avoidance regimen have excellent short-term survival and a low risk of first-year diabetes mellitus and PTLD. Rehospitalization remains common. These contemporary observations allow for improved caregiver and/or patient counseling and provide the necessary outcomes data to help design future randomized controlled trials., (Copyright © 2019 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Cardiomyopathies are a rare cause of pediatric heart disease, but they are one of the leading causes of heart failure admissions, sudden death, and need for heart transplant in childhood. Reports from the Pediatric Cardiomyopathy Registry (PCMR) have shown that almost 40% of children presenting with symptomatic cardiomyopathy either die or undergo heart transplant within 2 years of presentation. Little is known regarding circulating biomarkers as predictors of outcome in pediatric cardiomyopathy., Study Design: The Cardiac Biomarkers in Pediatric Cardiomyopathy (PCM Biomarkers) study is a multi-center prospective study conducted by the PCMR investigators to identify serum biomarkers for predicting outcome in children with dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). Patients less than 21 years of age with either DCM or HCM were eligible. Those with DCM were enrolled into cohorts based on time from cardiomyopathy diagnosis: categorized as new onset or chronic. Clinical endpoints included sudden death and progressive heart failure., Results: There were 288 children diagnosed at a mean age of 7.2±6.3 years who enrolled in the PCM Biomarkers Study at a median time from diagnosis to enrollment of 1.9 years. There were 80 children enrolled in the new onset DCM cohort, defined as diagnosis at or 12 months prior to enrollment. The median age at diagnosis for the new onset DCM was 1.7 years and median time from diagnosis to enrollment was 0.1 years. There were 141 children enrolled with either chronic DCM or chronic HCM, defined as children ≥2 years from diagnosis to enrollment. Among children with chronic cardiomyopathy, median age at diagnosis was 3.4 years and median time from diagnosis to enrollment was 4.8 years., Conclusion: The PCM Biomarkers study is evaluating the predictive value of serum biomarkers to aid in the prognosis and management of children with DCM and HCM. The results will provide valuable information where data are lacking in children., Clinical Trial Registration Nct01873976: https://clinicaltrials.gov/ct2/show/NCT01873976?term=PCM+Biomarker&rank=1., Competing Interests: Conflicts of Interest: None

Background: PGD is a complication after heart transplantation (OHT) and a significant cause of mortality, particularly in infant recipients. Lack of standardized definition of PGD in the pediatric population makes the prevalence and magnitude of impact unclear., Methods: ISHLT PGD consensus guidelines, which include inotrope scores and need for MCS, were applied retrospectively to 208 pediatric OHT recipients from a single institution from 1/2005-5/2016. PGD was defined as: moderate PGD-inotrope score >10 on postoperative day 1 (24-48 hours), and severe PGD-MCS within 24 hours (in the absence of detectable rejection)., Results: PGD occurred in 34 patients (16.3%); 14 of which had severe PGD (6.7%). Multivariate risk factors for PGD included CPB time (OR 10.3/10 min, 95% 10.05, 10.2, P = 0.03), Fontan palliation (OR 1.9, 95% 1.2, 3.97), and PCM (OR 5.65, 95% 1.52, 22.4); but not age, weight, ischemic time, or donor characteristics. Upon sub-analysis excluding patients with PCM, increased CPB was a significant multivariate risk factor (OR 10.09, 95% 9.89, 10.12, P = 0.003). Patients with PGD had decreased discharge survival compared to those without PGD (85% vs 96%, P < 0.01). Severe PGD was associated with the poorest 1-year survival (57% vs 91% without PGD, P = 0.04)., Conclusion: Patients with prolonged CPB are potentially at risk for developing PGD. Neither infant recipients nor donor characteristics were associated with an increased risk of PGD in the current era., (© 2019 Wiley Periodicals, Inc.)

Purpose To evaluate myocardial strain and circumferential transmural strain difference (cTSD; the difference between epicardial and endocardial circumferential strain) in a genotyped cohort with hypertrophic cardiomyopathy (HCM) and to explore correlations between cTSD and other anatomic and functional markers of disease status. Left ventricular (LV) dysfunction may indicate early disease in preclinical HCM (sarcomere mutation carriers without LV hypertrophy). Cardiac MRI feature tracking may be used to evaluate myocardial strain in carriers of HCM sarcomere mutation. Materials and Methods Participants with HCM and their family members participated in a prospective, multicenter, observational study (HCMNet). Genetic testing was performed in all participants. Study participants underwent cardiac MRI with temporal resolution at 40 msec or less. LV myocardial strain was analyzed by using feature-tracking software. Circumferential strain was measured at the epicardial and endocardial surfaces; their difference yielded the circumferential transmural strain difference (cTSD). Multivariable analysis to predict HCM status was performed by using multinomial logistic regression adjusting for age, sex, and LV parameters. Results Ninety-nine participants were evaluated (23 control participants, 34 participants with preclinical HCM [positive for sarcomere mutation and negative for LV hypertrophy], and 42 participants with overt HCM [positive for sarcomere mutation and negative for LV hypertrophy]). The average age was 25 years ± 11 and 44 participants (44%) were women. Maximal LV wall thickness was 9.5 mm ± 1.4, 9.8 mm ± 2.2, and 16.1 mm ± 5.3 in control participants, participants with preclinical HCM (P = .496 vs control participants), and participants with overt HCM (P < .001 vs control participants), respectively. cTSD for control participants, preclinical HCM, and overt HCM was 14% ± 4, 17% ± 4, and 22% ± 7, respectively (P < .01 for all comparisons). In multivariable models (controlling for septal thickness and log-transformed N-terminal brain-type natriuretic peptide), cTSD was predictive of preclinical and overt HCM disease status (P < .01). Conclusion Cardiac MRI feature tracking identifies myocardial dysfunction not only in participants with overt hypertrophic cardiomyopathy, but also in carriers of sarcomere mutation without left ventricular hypertrophy, suggesting that contractile abnormalities are present even when left ventricular wall thickness is normal. © RSNA, 2018 Online supplemental material is available for this article.

Anti-HLA donor-specific antibodies are associated with worse outcomes after organ transplantation. Among sensitized pediatric heart candidates, requirement for negative donor-specific cytotoxicity crossmatch increases wait times and mortality. However, transplantation with positive crossmatch may increase posttransplantation morbidity and mortality. We address this clinical challenge in a prospective, multicenter, observational cohort study of children listed for heart transplantation (Clinical Trials in Organ Transplantation in Children-04 [CTOTC-04]). Outcomes were compared among sensitized recipients who underwent transplantation with positive crossmatch, nonsensitized recipients, and sensitized recipients without positive crossmatch. Positive crossmatch recipients received antibody removal and augmented immunosuppression, while other recipients received standard immunosuppression with corticosteroid avoidance. This first CTOTC-04 report summarizes study rationale and design and relates pretransplantation sensitization status using solid-phase technology. Risk factors for sensitization were explored. Of 317 screened patients, 290 were enrolled and 240 underwent transplantation. Core laboratory evaluation demonstrated that more than half of patients were anti-HLA sensitized. Greater than 80% of sensitized patients had class I (with or without class II) HLA antibodies, and one-third of sensitized patients had at least 1 HLA antibody with median fluorescence intensity of ≥8000. Logistic regression models demonstrated male sex, weight, congenital heart disease history, prior allograft, and ventricular assist device are independent risk factors for sensitization., (© 2018 The American Society of Transplantation and the American Society of Transplant Surgeons.)

In October 2017, a pediatric heart transplant summit was held in Seattle-the first of its kind internationally-which focused solely upon controversies in pediatric end-stage heart failure management and pediatric heart transplantation. We selected five of the most popular and contentious topics and asked the speakers to provide a position paper. Worldwide, the vast majority of programs perform only a handful of pediatric heart transplants a year. Because of this, these "orphan" areas of investigation provide an opportunity for us as a community to aggregate our collective knowledge, which may represent the only viable way that we might sort through these complex and controversial issues in the field. We hope this represents the first of many such conferences and that this initial selection of papers encourages us to begin this collaborative process.

Background: Late gadolinium enhancement (LGE) on cardiac magnetic resonance imaging (CMR) is believed to represent dense replacement fibrosis. It is seen in ≈60% of adult patients with hypertrophic cardiomyopathy (HCM). However, the prevalence of LGE in children and adolescents with HCM is not well established. In addition, longitudinal studies describing the development and evolution of LGE in pediatric HCM are lacking. This study assesses the prevalence, progression, and clinical correlations of LGE in children and adolescents with, or genetically predisposed to, HCM., Methods: CMR scans from 195 patients ≤21 years of age were analyzed in an observational, retrospective study, including 155 patients with overt HCM and 40 sarcomere mutation carriers without left ventricular (LV) hypertrophy. The extent of LGE was quantified by measuring regions with signal intensity >6 SD above nulled remote myocardium., Results: Patients were 14.3±4.5 years of age at baseline and 68% were male. LGE was present in 70 (46%) patients with overt HCM (median extent, 3.3%; interquartile range, 0.8-7.1%), but absent in mutation carriers without LV hypertrophy. Thirty-one patients had >1 CMR (median interval between studies, 2.4 years; interquartile range, 1.5-3.2 years). LGE was detected in 13 patients (42%) at baseline and in 16 patients (52%) at follow-up CMR. The median extent of LGE increased by 2.4 g/y (range, 0-13.2 g/y) from 2.9% (interquartile range, 0.8-3.2%) of LV mass to 4.3% (interquartile range, 2.9-6.8%) ( P=0.02). In addition to LGE, LV mass and left atrial volume, indexed to body surface area, and z score for LV mass, as well, increased significantly from first to most recent CMR., Conclusions: LGE was present in 46% of children and adolescents with overt HCM, in contrast to ≈60% typically reported in adult HCM. In the subset of patients with serial imaging, statistically significant increases in LGE, LV mass, and left atrial size were detected over 2.5 years, indicating disease progression over time. Further prospective studies are required to confirm these findings and to better understand the clinical implications of LGE in pediatric HCM.

Background: Major neurologic events (MNEs) after heart transplantation (HTx) and their effect on survival have not been well described in children. In this study we aimed to characterize early MNEs (stroke, isolated seizures not from stroke and posterior reversible leukoencephalopathy [PRES] within 1 year after primary pediatric HTx) and evaluate their impact on 1-year post-HTx survival. We hypothesized that early an MNE after HTx is associated with decreased 1-year patient survival., Methods: We performed a pediatric, single-center, retrospective analysis of 345 consecutive patients aged 0 to 22 years who underwent primary HTx during the period from November 1, 1994 to October 31, 2015. Characteristics were compared between patients with and without early MNEs., Results: Nineteen percent (65 of 345) of patients had an MNE within 1 year after HTx (median 9 days, interquartile range [IQR] 4 to 23 days). Freedom from early MNE was 97%, 85% and 80% at 1, 6 and 12 months, respectively. Of the total 65 events, stroke comprised 55.4% (n = 36), isolated seizure 29.2% (n = 19) and PRES 15.4% (n = 10). With multiple logistic regression, previous neurologic disease, infection requiring intravenous antibiotic therapy and post-operative drug-treated hypertension were found to be significant risk factors for early MNEs. Stroke (hazard ratio 4.1, IQR 2.3 to 7.6, p < 0.0001), but not seizures and PRES, was associated with decreased 1-year patient survival., Conclusions: Major neurologic events are common after pediatric HTx and usually occur within the first few weeks. Early stroke was associated with decreased 1-year survival. Potentially modifiable factors, including prior neurologic event, drug-treated hypertension and infection, were associated with increased risk of developing early MNEs., (Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Data are lacking on RSB intensity and outcomes after pediatric heart transplantation. PHTS centers received a survey on RSB practices from 2005 to present. PHTS data were obtained for 2010-2013 and integrated with center-matched survey responses for analysis. Survey response rate was 82.6% (38/46). Centers were classified as low-, moderate-, and high-intensity programs based on RSB frequency (0-more than 8 RSB/y). RSB intensity decreased with increasing time from HT. Age at HT impacted RSB intensity mostly in year 1, with little to no impact in later years. Most centers have not replaced RSB with non-invasive methods, but many added ECHO and biomarker monitoring. Higher RSB intensity was not associated with decreased 4-year mortality (P=.63) or earlier detection of moderate to severe (ISHLT grade 2R/3R) cellular rejection (RSBMSR) in the first year (P=.87). First-year RSBMSR incidence did not differ with intensity or age at HT. Significant variability exists in RSB intensity, but with no impact on timing and incidence of RSBMSR or 4-year mortality. Reduction in RSB frequency may be safe in certain patients after pediatric HT., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: This study aimed to examine the role of nutrition in pediatric dilated cardiomyopathy (DCM)., Background: In adults with DCM, malnutrition is associated with mortality, whereas obesity is associated with survival., Methods: The National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry was used to identify patients with DCM and categorized by anthropometric measurements: malnourished (MN) (body mass index [BMI] <5% for age ≥2 years or weight-for-length <5% for <2 years), obesity (BMI >95% for age ≥2 years or weight-for-length >95% for <2 years), or normal bodyweight (NB). Of 904 patients with DCM, 23.7% (n = 214) were MN, 13.3% (n=120) were obese, and 63.1% (n=570) were NB., Results: Obese patients were older (9.0 vs. 5.7 years for NB; p < 0.001) and more likely to have a family history of DCM (36.1% vs. 23.5% for NB; p = 0.023). MN patients were younger (2.7 years vs. 5.7 years for NB; p < 0.001) and more likely to have heart failure (79.9% vs. 69.7% for NB; p = 0.012), cardiac dimension z-scores >2, and higher ventricular mass compared with NB. In multivariable analysis, MN was associated with increased risk of death (hazard ratio [HR]: 2.06; 95% confidence interval [CI]: 1.66 to 3.65; p < 0.001); whereas obesity was not (HR: 1.49; 95% CI: 0.72 to 3.08). Competing outcomes analysis demonstrated increased risk of mortality for MN compared with NB (p = 0.03), but no difference in transplant rate (p = 0.159)., Conclusions: Malnutrition is associated with increased mortality and other unfavorable echocardiographic and clinical outcomes compared with those of NB. The same effect of obesity on survival was not observed. Further studies are needed investigating the long-term impact of abnormal anthropometric measurements on outcomes in pediatric DCM. (Pediatric Cardiomyopathy Registry; NCT00005391)., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Impaired left atrial (LA) function is an early marker of cardiac dysfunction and predictor of adverse cardiac events. Herein, we assess LA structure and function in hypertrophy in hypertrophic cardiomyopathy (HCM) sarcomere mutation carriers with and without left ventricular hypertrophy (LVH)., Method: Seventy-three participants of the HCMNet study who underwent cardiovascular magnetic resonance (CMR) imaging were studied, including mutation carriers with overt HCM (n = 34), preclinical mutation carriers without HCM (n = 24) and healthy, familial controls (n = 15)., Results: LA volumes were similar between preclinical, control and overt HCM cohorts after covariate adjustment. However, there was evidence of impaired LA function with decreased LA total emptying function in both preclinical (64 ± 8%) and overt HCM (59 ± 10%), compared with controls (70 ± 7%; p = 0.002 and p = 0.005, respectively). LA passive emptying function was also decreased in overt HCM (35 ± 11%) compared with controls (47 ± 10%; p = 0.006). Both LAtotal emptying function and LA passive emptying function were inversely correlated with the extent of late gadolinium enhancement (LGE; p = 0.005 and p < 0.05, respectively), LV mass (p = 0.02 and p < 0.001) and interventricular septal thickness (p < 0.001 for both) and serum NT-proBNP levels (p < 0.001 for both)., Conclusion: LA dysfunction is detectable by CMR in preclinical HCM mutation carriers despite non-distinguishable LV wall thickness and LA volume. LA function appears most impaired in subjects with overt HCM and a greater extent of LV fibrosis.

Background: Studies of children with dilated cardiomyopathy (DCM) have suggested that improved survival has been primarily due to utilization of heart transplantation., Objectives: This study sought to determine transplant-free survival for these children over 20 years and identify the clinical characteristics at diagnosis that predicted death., Methods: Children <18 years of age with some type of DCM enrolled in the Pediatric Cardiomyopathy Registry were divided by year of diagnosis into an early cohort (1990 to 1999) and a late cohort (2000 to 2009). Competing risks and multivariable modeling were used to estimate the cumulative incidence of death, transplant, and echocardiographic normalization by cohort and to identify the factors associated with death., Results: Of 1,953 children, 1,199 were in the early cohort and 754 were in the late cohort. Most children in both cohorts had idiopathic DCM (64% vs. 63%, respectively). Median age (1.6 vs. 1.7 years), left ventricular end-diastolic z-scores (+4.2 vs. +4.2), and left ventricular fractional shortening (16% vs. 17%) at diagnosis were similar between cohorts. Although the rates of echocardiographic normalization (30% and 27%) and heart transplantation (24% and 24%) were similar, the death rate was higher in the early cohort than in the late cohort (18% vs. 9%; p = 0.04). Being in the early cohort (hazard ratio: 1.4; 95% confidence interval: 1.04 to 1.9; p = 0.03) independently predicted death., Conclusions: Children with DCM have improved survival in the more recent era. This appears to be associated with factors other than heart transplantation, which was equally prevalent in both eras. (Pediatric Cardiomyopathy Registry [PCMR]; NCT00005391)., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Sarcomeric gene mutation carriers without overt left ventricular hypertrophy (G+/LVH-) can harbour subclinical changes in cardiovascular structure and function that precede the development of hypertrophic cardiomyopathy (HCM). We sought to investigate if circulating biomarkers of cardiovascular stress and collagen metabolism among G+/LVH- individuals, measured at rest and following exercise provocation, yield further insights into the underlying biology of HCM., Methods: We studied 76 individuals with overt HCM, 50 G+/LVH- individuals and 41 genotype-negative related controls enrolled in a cross-sectional, multicentre observational study (HCMNet). Biomarkers of cardiac stress (N-terminal pro-B-type natriuretic peptide, NT-proBNP; high-sensitivity troponin I, hsTnI; soluble ST2) and fibrosis (carboxy-terminal propeptide of procollagen type I; C-terminal telopeptide of type I collagen; galectin-3; periostin) were measured., Results: Individuals with overt HCM had elevated NT-proBNP and hsTnI compared with G+/LVH- subjects and controls at rest, along with an exaggerated increase in NT-proBNP and hsTnI in response to exercise. We found no detectable differences in resting or exercise-provoked biomarker profiles of cardiovascular stress and fibrosis among G+/LVH- individuals compared with healthy controls despite subtle echocardiographic differences in cardiac structure and function., Conclusion: Dynamic exercise testing exaggerated resting differences in natriuretic peptides and troponin elevations among individuals with overt HCM. In contrast, we found no differences in biomarker profiles of cardiovascular stress and fibrosis among G+/LVH- individuals compared with controls even after maximal exercise provocation. Our findings highlight the need for continued investigation into early phenotypes of sarcomeric gene mutations and the evolution of HCM., Competing Interests: Competing interests: PJ has received research support from Abbott Laboratories, Amgen, AstraZeneca LP, Beckman Coulter, Daiichi Sankyo, GlaxoSmithKline, Merck & Co, Roche Diagnostics Corporation, Takeda Global Research and Development Center, and Waters Technologies Corporation.

Background: End-stage renal disease (ESRD), defined as the need for chronic dialysis and/or kidney transplantation (KTx), is a known complication after heart transplant (HTx). However, factors associated with ESRD are not well elucidated. The objectives of this study were to determine the prevalence, risk factors, and outcomes associated with ESRD after pediatric HTx., Methods: Scientific Registry of Transplant Recipients data were linked, using direct identifiers, to the United States Renal Data System to identify patients (aged ≤ 18 years) who underwent primary HTx between 1989 and 2013. Risk factors for ESRD and death were analyzed using Cox regression analysis., Results: Combining the above 2 databases identified ~25% additional HTx patients who developed ESRD that were not captured by either database alone. During a median follow-up of 11.8 years, ESRD developed in 276 of 6,901 patients (4%). The actuarial risk of developing ESRD after HTx was 3% at 10 years and 16% at 20 years. Age at HTx > 1 year, African-American race, year of HTx before 2000, hypertension, diabetes mellitus, re-HTx, acute dialysis, graft failure, and hospitalized infection were significant risk factors for ESRD development. Those who remained on chronic dialysis had higher risk of death than those who received KTx (hazard ratio, 31.4; 95% confidence interval, 20.8-48.4; p < 0.0001)., Conclusions: ESRD after pediatric HTx is more prevalent in HTx survivors than documented by a transplant database alone. A number of factors develop at or after HTx that increase the risk for developing ESRD. Use of KTx in post-HTx ESRD is associated with improved survival., (Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Pediatric dilated cardiomyopathy (DCM) is the most common indication for heart transplantation in children. Despite similar genetic etiologies, medications routinely used in adult heart failure patients do not improve outcomes in the pediatric population. The mechanistic basis for these observations is unknown. We hypothesized that pediatric and adult DCM comprise distinct pathological entities, in that children do not undergo adverse remodeling, the target of adult heart failure therapies. To test this hypothesis, we examined LV specimens obtained from pediatric and adult donor controls and DCM patients. Consistent with the established pathophysiology of adult heart failure, adults with DCM displayed marked cardiomyocyte hypertrophy and myocardial fibrosis compared with donor controls. In contrast, pediatric DCM specimens demonstrated minimal cardiomyocyte hypertrophy and myocardial fibrosis compared with both age-matched controls and adults with DCM. Strikingly, RNA sequencing uncovered divergent gene expression profiles in pediatric and adult patients, including enrichment of transcripts associated with adverse remodeling and innate immune activation in adult DCM specimens. Collectively, these findings reveal that pediatric and adult DCM represent distinct pathological entities, provide a mechanistic basis to explain why children fail to respond to adult heart failure therapies, and suggest the need to develop new approaches for pediatric DCM.

We aimed to examine trends in ventricular assist device (VAD) selection, continuous flow devices (CFD) versus pulsatile flow devices (PFD), and their associated outcomes in children eligible for both device types. To accomplish this, the United Network for Organ Sharing database was reviewed for pediatric patients listed for heart transplant (HT) from January 2007 to June 2014. Patients were included if a durable VAD was present at wait listing or when removed from the waiting list and who met size eligibility for a CFD (BSA > 1.0 m). In total, 253 patients met inclusion criteria, 144 (57%) CFD and 109 (43%) PFD. Device type varied significantly based on year with CFD increasing from 11% in 2007 to 88% in 2014 (p < 0.01). PFD patients were younger, had a lower BSA, and an increased rate of extracorporeal membrane oxygenation and biventricular assist device support at listing. Survival to transplant or recovery was similar for CFDs and PFDs (96 vs. 94%; p = 0.57), as was the post-HT survival, 95% for both device types. Despite PFD patients having more risk factors for a poor outcome, survival was similar between device types. Even so, there is a dramatic trend toward CFD utilization in patients who are large enough to support one.

Importance: Sarcomere mutations and left ventricular (LV) hypertrophy (LVH) are cardinal features of hypertrophic cardiomyopathy (HCM). However, little is known about the full spectrum of phenotypic manifestations or how LVH influences disease expression., Objectives: (1) To characterize and assess phenotypic burden in sarcomere mutation carriers (genotype positive [G+]) and (2) to investigate the correlation between LV wall thickness (LVWT) and other disease features in mutation carriers., Design, Setting, and Participants: This investigation was a cross-sectional, multicenter observational study in the setting of the HCMNet network of HCM clinical centers. Mutation carriers with LVH (G+/LVH+), mutation carriers without LVH (G+/LVH-), and healthy related control individuals (G-/LVH-) were enrolled through HCMNet sites. A total of 193 participants were enrolled and underwent study procedures. Participants were enrolled between April 9, 2010, and January 30, 2012. Study analysis was performed between June 2015 and May 2016., Exposures: The primary stratifying variables were the presence of a sarcomere mutation and measures of LVWT., Main Outcomes and Measures: Variables from standardized exercise testing, echocardiography, cardiac magnetic resonance imaging, serum biomarker measurement, and electrocardiography were compared across study cohorts., Results: Analyses were performed in 178 participants, including 81 G+/LVH+ (mean [SD] age at baseline, 27 [14] years), 55 G+/LVH- (20 [10] years), and 42 G-/LVH- (18 [8] years). All mutation carriers had smaller LV cavity, higher ratio of LVWT to diastolic diameter, and higher echocardiographic LV ejection fraction than controls. A phenotypic burden score was evaluated as the cumulative number of 7 traits (changes on electrocardiography; decreased LV systolic, diastolic diameter, or septal E' velocity; higher ratio of LVWT to diastolic diameter; serum troponin level; and natriuretic peptide level) in each individual. The mean (SE) phenotypic burden was 4.9 (0.2) phenotypes per individual in G+/LVH+, 2.4 (0.2) in G+/LVH-, and 1.3 (0.2) in controls (P < .001). Classification and regression tree analysis identified an LV end-diastolic dimension z score less than -1.85 or the combination of an LV end-diastolic dimension z score of -1.85 or higher and a septal E' velocity z score less than -0.52 as having 74% accuracy in discriminating G+/LVH- participants from controls. In mutation carriers, clinical variables demonstrated a continuous correlation with LVWT, generally without a clear cutoff signifying pathologic transition., Conclusions and Relevance: G+/LVH- individuals demonstrated altered cardiac dimensions and function and a higher burden of early phenotypes than healthy G- controls. Two methods discriminated phenotypic subgroups, namely, a sum across 7 traits and a regression tree-based rule that identifies constellations of distinguishing factors. Greater LVWT is associated with more prominent cardiac abnormalities in a continuous, although not always linear, manner. A single value of LVWT could not dichotomize the presence or absence of disease.

Background: The effect of age at transplant on rejection detected by routine surveillance biopsy (RSB) in pediatric heart transplant (HT) recipients is unknown. We hypothesized there would be low diagnostic yield and decreased prevalence of rejection detected on RSB in infants (age <1 year) when compared with children (age 1 to 9 years) and adolescents (age 10 to 18 years)., Methods: We utilized Pediatric Heart Transplant Study (PHTS) data from 2010 to 2013 to analyze moderate-to-severe (ISHLT Grade 2R/3R) cellular rejection (MSR) detected only on RSB (RSBMSR)., Results: RSB detected 280 of 343 (81.6%) episodes of MSR. RSBMSR was detected in all age groups even >5 years after HT. Infant RSBMSR had a greater proportion (p = 0.0025) occurring >5 years after HT (39.2 vs 18.4 vs 10.8%) and a lower proportion (p = 0.0009) occurring in the first year after HT (25.5 vs 60.6 vs 51.7%) compared with children and adolescents, respectively. Freedom from RSBMSR was 87 ± 7% in infants, 76 ± 6% in children and 73 ± 7% in adolescents 4 years after HT. In 1-year survivors who had RSBMSR in the first year after HT, the risk of RSBMSR occurring in Years 2 to 4 was significantly (p < 0.0001) greater than patients without RSBMSR in the first year (hazard ratio 21.28, 95% confidence interval 10.87 to 41.66), regardless of recipient age., Conclusions: RSBMSR exists in all age groups after pediatric HT with long-term follow-up. The prevalence in infant recipients is highest >5 years after HT. Those with RSBMSR in the first year after HT are at a high risk for recurrent rejection regardless of age at HT., (Copyright © 2017 International Society for Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.)

Background: Historically, patients with a prior Fontan procedure for complex congenital heart disease (CHD) have been considered at higher risk for death after heart transplant (HT) compared with other HT transplant candidates. With the overall trend of improved survival of pediatric HT recipients, it is unclear of Fontan patient post-HT survival has also improved in the current era., Methods: Data from the Pediatric Heart Transplant Study database for Fontan patients who underwent HT was compared between the early era (1993 to 2006, n = 150) and late era (2007 to 2014, n = 252). Post-HT survival and pre-HT characteristics were compared among eras and also with non-Fontan CHD patients., Results: At time of HT, Fontan patients in the late era were more likely to require inotropic support, have protein-losing enteropathy, have failure to thrive, and be further from time of Fontan, although less likely to be on ventilator support. Only ventilator support and earlier year of HT were significant risk factors for death in the multivariate analysis. Post-HT Fontan patient survival significantly improved from the early to late era (p = 0.02), particularly in the early phase, with 1-year survival of 77% in the early era and 89% in the late era. Late era non-Fontan CHD patient 1-year post-HT survival was similar to Fontan patients at 92%., Conclusions: Survival of Fontan patients after HT has significantly improved in the current era. Currently, expected post-HT survival for Fontan patients is on par with other CHD patients. Fontan patients should not be excluded from consideration for HT solely on a history of Fontan., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

The Berlin Heart EXCOR Pediatric Ventricular Assist Device (BH) was approved for use in the United States in December 2011, based on a prospective investigational device exemption (IDE) trial. Strict exclusion criteria for the trial selected a low-risk "ideal" cohort. We sought to determine whether postapproval usage of the BH in a "real world" cohort of recipients would result in similar outcomes. Preimplant diagnostic information was collected for all patients. Efficacy was evaluated by comparison of all children (efficacy group, n = 247) implanted between FDA approval and April 2015 to those in the IDE trial (IDE, n = 48), with regard to achievement of one of four end-states: transplanted, successful weaning, death/unsuccessful weaning, or still-on-device. Safety outcomes were compared between IDE patients and a subset of postapproval patients (safety group, n = 39) for whom adjudicated adverse events were tracked in a regulator-mandated dataset. Diagnostic categories were similar between groups: IDE (congenital 19%, dilated cardiomyopathy/myocarditis/other 81%) versus Efficacy Group (congenital 24%, dilated cardiomyopathy/myocarditis/other 75%). Patients in the IDE cohort were larger (median 14.8 kg, range 3.6-58.1 kg vs. 10.7 kg, 2.9-112.0 kg, p = 0.02). More IDE patients were successfully supported than in the efficacy group cohort (90% vs. 77%, p = 0.05). Proportions with bleeding and stroke were similar between the IDE and safety group cohorts (46% vs. 41%, p = 0.65; 29% vs. 33%, p = 0.68, respectively). With usage of the BH in a less-ideal population, rates of bridge to transplant and weaning have declined slightly, but remain encouragingly high. Bleeding and neurologic event rates have not increased.

Background: Research comparing the survival of children with familial dilated cardiomyopathy (FDCM) to that of children with idiopathic dilated cardiomyopathy (IDCM) has produced conflicting results., Methods and Results: We analyzed data from children with FDCM or IDCM using the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry. Compared to children with IDCM (n=647), children with FDCM (n=223) were older (mean 6.2 versus 4.5 years, P <0.001), less often had heart failure (64% versus 78%, P <0.001), had less-depressed mean left ventricular fractional shortening z scores (-7.85±3.98 versus -9.06±3.89, P <0.001) and lower end-diastolic dimension z scores (4.12±2.61 versus 4.91±2.57, P <0.001) at diagnosis. The cumulative incidence of death was lower for patients with FDCM compared with IDCM ( P =0.04; hazard ratio 0.64, P =0.06), but no difference in risk of transplant or the combined death or transplant outcome. There was no difference in the proportion of children with echocardiographic normalization at 3 years of follow-up (FDCM, 30% versus IDCM, 26%; P =0.33). Multivariable analysis showed no difference in outcomes between FDCM and IDCM but for both groups older age, congestive heart failure, and increased left ventricular end-systolic dimension z score at diagnosis were independently associated with an increased risk of death or heart transplantation (all P s<0.001)., Conclusions: There was no survival difference between FDCM and IDCM after adjustment for other factors. Older age, congestive heart failure, and greater left ventricular dilation at diagnosis were independently associated with increased risk of the combined end point of death or transplantation., Clinical Trial Registration: URL: https://clinicaltrials.gov. Unique identifier: NCT00005391., (© 2017 American Heart Association, Inc.)

Crude oil is currently transported primarily by pipelines and rail from extraction sites to refineries around the world. This research evaluates energy use and greenhouse gas (GHG) emissions for three scenarios (synthetic crude oil and dilbit with and without diluent return) in which 750 000 bpd of Alberta's bitumen is transported 3000 km to determine which method has a lower environmental impact. Each scenario has a pipeline and rail pathway, and the dilbit without diluent return scenario has an additional heated bitumen pathway, which does not require diluent. An Excel based bottom-up model is developed using engineering first-principles to calculate mass and energy balances for each process. Results show that pipeline transportation produced between 61% and 77% fewer GHG emissions than by rail. The GHG emissions decreased by 15% and 73% for rail and pipelines as the capacity increased from 100 000 to 800 000 bpd. A Monte Carlo simulation was performed to determine the uncertainty in the emissions and found that the uncertainty was larger for pipelines (up to ±73%) and smaller for rail (up to ±28%). The uncertainty ranges do not overlap, thus confirming that pipelines have lower GHG emissions, which is important information for policy makers conducting pipeline reviews.