The Fontan Udenafil Exercise Longitudinal Trial: Subgroup Analysis

The Pediatric Heart Network's Fontan Udenafil Exercise Longitudinal (FUEL) Trial (Mezzion Pharma Co. Ltd., NCT02741115) demonstrated improvements in some measures of exercise capacity and in the myocardial performance index following 6 months of treatment with udenafil (87.5 mg twice daily). In this post hoc analysis, we evaluate whether subgroups within the population experienced a differential effect on exercise performance in response to treatment. The effect of udenafil on exercise was evaluated within subgroups defined by baseline characteristics, including peak oxygen consumption (VO2), serum brain-type natriuretic peptide level, weight, race, gender, and ventricular morphology. Differences among subgroups were evaluated using ANCOVA modeling with fixed factors for treatment arm and subgroup and the interaction between treatment arm and subgroup. Within-subgroup analyses demonstrated trends toward quantitative improvements in peak VO2, work rate at the ventilatory anaerobic threshold (VAT), VO2 at VAT, and ventilatory efficiency (VE/VCO2) for those randomized to udenafil compared to placebo in nearly all subgroups. There was no identified differential response to udenafil based on baseline peak VO2, baseline BNP level, weight, race and ethnicity, gender, or ventricular morphology, although participants in the lowest tertile of baseline peak VO2 trended toward larger improvements. The absence of a differential response across subgroups in response to treatment with udenafil suggests that the treatment benefit may not be restricted to specific sub-populations. Further work is warranted to confirm the potential benefit of udenafil and to evaluate the long-term tolerability and safety of treatment and to determine the impact of udenafil on the development of other morbidities related to the Fontan circulation.Trial Registration NCT0274115.

Variation in provider compliance with sports restriction guidelines in children with an isolated bicuspid aortic valve

BACKGROUND

Published guidelines for sports restriction for children with a bicuspid aortic valve remain controversial. We sought to describe practice variation and factors influencing sports restrictions in these children.

METHODS

This retrospective single-centre study included children (7-18 years old) with an isolated bicuspid aortic valve at baseline from 1 January, 2005 to 31 December, 2014. Sports restrictions, factors potentially influencing decision-making, and outcomes were collected. Descriptive statistics and multivariable mixed-effects logistic regression models were performed with providers and patients as random effects. Provider variation was estimated using intraclass correlation coefficients. Odds ratios, 95% confidence intervals, and p-values were reported from the models.

RESULTS

In 565 encounters (253 children; 34 providers), 41% recommended no sports restrictions, 40% recommended high-static and high-dynamic restrictions, and 19% had no documented recommendations. Based on published guidelines, 22% of children were inappropriately restricted while 30% were not appropriately restricted. The paediatric cardiology provider contributed to 37% of observed practice variation (p < 0.001). Sports restriction was associated with older age, males, greater ascending aorta z-score, and shorter follow-up interval. There were no aortic dissections or deaths and one cardiac intervention.

CONCLUSION

Physicians frequently fail to document sports restrictions for children with a bicuspid aortic valve, and documented recommendations often conflict with published guidelines. Despite this, no adverse outcomes occurred. Providers accounted for a significant proportion of the variation in sports restrictions. Further research to provide evidence-based guidelines may improve provider compliance with activity recommendations in this population.

Transcatheter and Surgical Aortic Valve Implantation in Children, Adolescents, and Young Adults With Congenital Heart Disease

Transcatheter aortic valve implantation (TAVI) is common in adults but rare in children and adolescents. Since 2014, our institution has incorporated a transcatheter approach as an option for aortic valve replacement in this population. The purpose of this study was to compare short-term outcomes of TAVI with surgical aortic valve replacement (SAVR). This single-center, retrospective study included patients aged 10 to 21 years who had a native SAVR or TAVI between January 2010 to April 2020. Comparative analysis of baseline characteristics and a composite outcome (stroke within 6 months, readmission within 30 days, death) between SAVR and TAVI were made using chi-square test or Wilcoxon rank sum test, as appropriate. Of the 77 patients who underwent native aortic valve implantation during the study period (60 SAVR, 17 TAVI), 46 were aged 10 to 21 years (30 SAVR, 16 TAVI). Median follow-up was 3.8 years (interquartile range 1.5 to 4.9) for the SAVR group and 1.5 years (interquartile range 1.1 to 1.2) for the TAVI group. There was no difference in the composite outcome between groups. Patients in the SAVR group were more likely to have undergone concomitant surgical intervention and have longer intensive care unit and hospital stays. In conclusion, our study suggests similar short-term outcomes between SAVR and TAVI in children and young adults aged 10 to 21 years. Longer-term studies are essential to understand the utility of TAVI and to better consider the option of a transcatheter approach as an alternative to SAVR in the pediatric population.

Prenatally diagnosed pseudoaneurysm of mitral-aortic intervalvular fibrous area

The mitral-aortic intervalvular fibrosa (MAIVF) is an avascular, fibrous structure that provides continuity between the anterior leaflet of the mitral valve and the aortic valve. Pseudoaneurysm of the MAIVF is rare and has been most commonly described in adults and, more rarely, in children following cardiac surgery or endocarditis. Few reports have been published on cases with congenital pseudoaneurysm of the MAIVF. Here, we describe five cases of congenital pseudoaneurysm of the MAIVF identified prenatally and an additional six cases diagnosed postnatally. This is an unusual finding of varying clinical significance, which can be isolated or associated with complex congenital heart disease but, importantly, can be identified and monitored in the fetus. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Left ventricular thrombus in the multisystem inflammatory syndrome in children associated with COVID-19

A 3-year-old girl presenting with fever, mucocutaneous inflammation, and acute gastrointestinal symptoms met criteria for the multisystem inflammatory syndrome in children associated with COVID-19 (MIS-C). Echocardiography showed severely decreased left ventricular (LV) function with an apical mass. After treatment with intravenous (IV) immunoglobulin, IV steroids, anakinra, milrinone, and systemic anticoagulation, her LV function rapidly improved and the mass became increasingly mobile. Given the risk of systemic embolization, the mass was excised through left ventriculotomy and pathology confirmed a thrombus.

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.

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.

Exercise Capacity and Predictors of Performance After Fontan: Results from the Pediatric Heart Network Fontan 3 Study

Impaired exercise following Fontan is a surrogate of morbidity. Single-center longitudinal data exist, but there is a lack of contemporary multi-center data. Ramp cycle ergometry was re-performed in consented participants who had originally participated in the Pediatric Heart Network's Fontan cross-sectional study. Annualized change was evaluated at maximal and submaximal exercise. Associations between these outcomes and patient characteristics were analyzed. There were 336 participants in Fontan 3, mean age 23.2 years. Paired measurements of peak oxygen consumption (peak VO₂) were available for 95; peak exercise data at Fontan 3 were available for 275. Percent-predicted peak VO₂ declined by 0.8 ± 1.7% per year (p < 0.001). At Fontan 3, the lowest performing peak VO₂ tertile had the highest rate of overweight and obesity (p < 0.001). Female gender was more prevalent in the highest performing tertile (p = 0.004). Paired data at the ventilatory anaerobic threshold (VO₂ at VAT) were available for 196; VAT data at Fontan 3 were available for 311. Percent-predicted VO₂ at VAT decreased by 0.8 ± 2.6% per year (p < 0.001). At Fontan 3, VO₂ at VAT was better preserved than peak VO₂ across all tertiles, with higher rates of overweight and obesity in the lower performing group (p = 0.001). Female gender (p < 0.001) and left ventricular morphology (p = 0.03) were associated with better performance. Submaximal exercise is better preserved than maximal in the Fontan population, but declined at the same rate over the study period. The overall longitudinal rate of decline in exercise performance is slower than what has been described previously.

The importance of expert review to clarify ambiguous situations for (Q)SAR predictions under ICH M7

The use of in silico predictions for the assessment of bacterial mutagenicity under the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) M7 guideline is recommended when two complementary (quantitative) structure-activity relationship (Q)SAR models are used. Using two systems may increase the sensitivity and accuracy of predictions but also increases the need to review predictions, particularly in situations where results disagree. During the 4th ICH M7/QSAR Workshop held during the Joint Meeting of the 6th Asian Congress on Environmental Mutagens (ACEM) and the 48th Annual Meeting of the Japanese Environmental Mutagen Society (JEMS) 2019, speakers demonstrated their approaches to expert review using 20 compounds provided ahead of the workshop that were expected to yield ambiguous (Q)SAR results. Dr. Chris Barber presented a selection of the reviews carried out using Derek Nexus and Sarah Nexus provided by Lhasa Limited. On review of these compounds, common situations were recognised and are discussed in this paper along with standardised arguments that may be used for such scenarios in future.

Stability of Oxandrolone in Medium-Chain Triglyceride Oil and Pharmacokinetics Following Buccal Administration of the Extemporaneous Formulation in Neonates and Adults

OBJECTIVES Growth failure following surgical palliation of complex congenital heart defects (CHDs) is a prognosticator of poor outcomes. Many strategies for improving weight gain have been implemented in this population, with limited success. We recently described the potential of the anabolic steroid oxandrolone to improve weight gain following surgical repair of CHD when administered via a medium-chain triglyceride (MCT) oil suspension to the buccal mucosa. The current study evaluates the stability of oxandrolone in the MCT oil formulation, as well as the pharmacokinetics of oxandrolone when administered via buccal mucosa in both neonates and adults.

METHODS Stability was assessed by long-term storage of the preparation 1) at ambient conditions and 2) under photodegradative conditions for 3 days. Neonatal pharmacokinetic parameters were determined in a cohort of neonates following surgical CHD repair, whereas adult pharmacokinetics parameters were collected as part of a prospective study to evaluate the relative bioavailability of the oxandrolone in MCT oil formulation.

RESULTS We found that oxandrolone was stable in the MCT oil formulation for at least 1 month, although exposure to light hastened drug degradation. Both neonatal and adult oxandrolone pharmacokinetics were variable; however, oxandrolone in MCT oil was relatively well absorbed through the buccal mucosa (mean bioavailability = 62.5%).

CONCLUSIONS These data suggest that the variability in oxandrolone exposures is inherent to the drug, and not the formulation or route of administration. Combined, these data support further study of this novel oxandrolone in MCT oil formulation and its impact on growth following complex surgical repair of CHD in neonates.

Revisiting the bacterial mutagenicity assays: Report by a workgroup of the International Workshops on Genotoxicity Testing (IWGT)

The International Workshop on Genotoxicity Testing (IWGT) meets every four years to obtain consensus on unresolved issues associated with genotoxicity testing. At the 2017 IWGT meeting in Tokyo, four sub-groups addressed issues associated with the Organization for Economic Cooperation and Development (OECD) Test Guideline TG471, which describes the use of bacterial reverse-mutation tests. The strains sub-group analyzed test data from >10,000 chemicals, tested additional chemicals, and concluded that some strains listed in TG471 are unnecessary because they detected fewer mutagens than other strains that the guideline describes as equivalent. Thus, they concluded that a smaller panel of strains would suffice to detect most mutagens. The laboratory proficiency sub-group recommended (a) establishing strain cell banks, (b) developing bacterial growth protocols that optimize assay sensitivity, and (c) testing "proficiency compounds" to gain assay experience and establish historical positive and control databases. The sub-group on criteria for assay evaluation recommended that laboratories (a) track positive and negative control data; (b) develop acceptability criteria for positive and negative controls; (c) optimize dose-spacing and the number of analyzable doses when there is evidence of toxicity; (d) use a combination of three criteria to evaluate results: a dose-related increase in revertants, a clear increase in revertants in at least one dose relative to the concurrent negative control, and at least one dose that produced an increase in revertants above control limits established by the laboratory from historical negative controls; and (e) establish experimental designs to resolve unclear results. The in silico sub-group summarized in silico utility as a tool in genotoxicity assessment but made no specific recommendations for TG471. Thus, the workgroup identified issues that could be addressed if TG471 is revised. The companion papers (a) provide evidence-based approaches, (b) recommend priorities, and (c) give examples of clearly defined terms to support revision of TG471.

Improvement of quantitative structure-activity relationship (QSAR) tools for predicting Ames mutagenicity: outcomes of the Ames/QSAR International Challenge Project

The International Conference on Harmonization (ICH) M7 guideline allows the use of in silico approaches for predicting Ames mutagenicity for the initial assessment of impurities in pharmaceuticals. This is the first international guideline that addresses the use of quantitative structure–activity relationship (QSAR) models in lieu of actual toxicological studies for human health assessment. Therefore, QSAR models for Ames mutagenicity now require higher predictive power for identifying mutagenic chemicals. To increase the predictive power of QSAR models, larger experimental datasets from reliable sources are required. The Division of Genetics and Mutagenesis, National Institute of Health Sciences (DGM/NIHS) of Japan recently established a unique proprietary Ames mutagenicity database containing 12140 new chemicals that have not been previously used for developing QSAR models. The DGM/NIHS provided this Ames database to QSAR vendors to validate and improve their QSAR tools. The Ames/QSAR International Challenge Project was initiated in 2014 with 12 QSAR vendors testing 17 QSAR tools against these compounds in three phases. We now present the final results. All tools were considerably improved by participation in this project. Most tools achieved >50% sensitivity (positive prediction among all Ames positives) and predictive power (accuracy) was as high as 80%, almost equivalent to the inter-laboratory reproducibility of Ames tests. To further increase the predictive power of QSAR tools, accumulation of additional Ames test data is required as well as re-evaluation of some previous Ames test results. Indeed, some Ames-positive or Ames-negative chemicals may have previously been incorrectly classified because of methodological weakness, resulting in false-positive or false-negative predictions by QSAR tools. These incorrect data hamper prediction and are a source of noise in the development of QSAR models. It is thus essential to establish a large benchmark database consisting only of well-validated Ames test results to build more accurate QSAR models.

Extrapolation of in vitro structural alerts for mutagenicity to the in vivo endpoint

As part of the hazard and risk assessment of chemicals in man, it is important to assess the ability of a chemical to induce mutations in vivo. Because of the commonalities in the molecular initiating event, mutagenicity in vitro can correlate well to the in vivo endpoint for certain compound classes; however, the difficulty lies in identifying when this correlation holds true. In silico alerts for in vitro mutagenicity may therefore be used as the basis for alerts for mutagenicity in vivo where an expert assessment is carried out to establish the relevance of the correlation. Taking this into account, a data set of publicly available transgenic rodent gene mutation assay data, provided by the National Institute of Health Sciences of Japan, was processed in the expert system Derek Nexus against the in vitro mutagenicity endpoint. The resulting predictivity was expertly reviewed to assess the validity of the observed correlations in activity and mechanism of action between the two endpoints to identify suitable in vitro alerts for extension to the in vivo endpoint. In total, 20 alerts were extended to predict in vivo mutagenicity, which has significantly improved the coverage of this endpoint in Derek Nexus against the data set provided. Updating the Derek Nexus knowledge base in this way led to an increase in sensitivity for this data set against this endpoint from 9% to 66% while maintaining a good specificity of 89%.

Important considerations for the validation of QSAR models for in vitro mutagenicity

While high-level performance metrics generated from the validation of quantitative structure-activity relationship (QSAR) systems can provide valuable information on how well these models perform and where they need to be improved, they require appropriate interpretation. There is no universal performance metric which will answer all of the questions a user might ask relating to a model, and therefore, a combination of metrics should usually be considered. Furthermore, results may vary according to the chemical space being used to validate a model, and, in some cases, it may be the validation data which is lacking or ambiguous rather than the prediction being made. Finally, users also need to consider the interpretability of the predictions being made, alongside the accuracy of the predictions. In this paper, we will discuss these important considerations in more detail within the context of the results obtained at Lhasa Limited as part of the National Institute of Health Sciences (NIHS) QSAR challenge project.

Information-Derived Mechanistic Hypotheses for Structural Cardiotoxicity

Adverse events resulting from drug therapy can be a cause of drug withdrawal, reduced and or restricted clinical use, as well as a major economic burden for society. To increase the safety of new drugs, there is a need to better understand the mechanisms causing the adverse events. One way to derive new mechanistic hypotheses is by linking data on drug adverse events with the drugs' biological targets. In this study, we have used data mining techniques and mutual information statistical approaches to find associations between reported adverse events collected from the FDA Adverse Event Reporting System and assay outcomes from ToxCast, with the aim to generate mechanistic hypotheses related to structural cardiotoxicity (morphological damage to cardiomyocytes and/or loss of viability). Our workflow identified 22 adverse event-assay outcome associations. From these associations, 10 implicated targets could be substantiated with evidence from previous studies reported in the literature. For two of the identified targets, we also describe a more detailed mechanism, forming putative adverse outcome pathways associated with structural cardiotoxicity. Our study also highlights the difficulties deriving these type of associations from the very limited amount of data available.

Digoxin Use in Infants with Single Ventricle Physiology: Secondary Analysis of the Pediatric Heart Network Infant Single Ventricle Trial Public Use Dataset

Digoxin has been associated with reduced interstage mortality after Norwood procedure. We sought to determine its association with survival and change in weight-for-age Z-score (WAZ) before the superior cavopulmonary connection (SCPC) surgery and at 14 months in a heterogeneous group of single ventricle infants. We performed a post-hoc analysis of the Pediatric Heart Network Infant Single Ventricle public use dataset to determine associations between digoxin and survival, transplant-free survival, and change in WAZ pre-SCPC and at 14 months. Sub-analyses of survival and transplant-free survival were performed for subjects who underwent Damus-Kaye-Stansel (DKS)/Norwood. Propensity score weighting was used in Cox hazard-proportion models. Of 229 subjects, 82 (36%) received digoxin and 147 (64%) received no digoxin. Pre-SCPC and 14-month survival and transplant-free survival were not significantly different between the digoxin and no digoxin groups for the main cohort and DKS/Norwood sub-group. However, in DKS/Norwood subjects there was a trend towards improved interstage transplant-free survival in the digoxin group (95.7 vs. 89.6%, p = 0.08). Digoxin was associated with a greater decrease in WAZ from birth to pre-SCPC (- 1.96 ± 0.19 vs. - 1.31 ± 0.18, p < 0.001) and birth to 14 months (- 0.64 ± 0.15 vs. - 0.19 ± 0.15, p = 0.03). Digoxin was not associated with improved survival during the interstage or at 14 months in a mixed single ventricle cohort, but there was a trend towards improved interstage transplant-free survival in post-Norwood infants. As digoxin was associated with poorer weight gain, further research is needed to identify the risks/benefits for anatomic subtypes of infants with single ventricles.

Disease progression and variation in clinical practice for isolated bicuspid aortic valve in children

BACKGROUND

Disease progression of an isolated bicuspid aortic valve (BAV) in children is poorly understood and adult management guidelines may not be applicable. Thus, we sought to evaluate disease progression of pediatric isolated BAV and its relationship to current management practices.

METHODS

Children with a BAV and ≤mild aortic stenosis (AS) and/or aortic regurgitation (AR) at the time of initial evaluation were included in this retrospective cohort study (1/2005-12/2014). Outcomes included change in z-scores for aortic root and ascending aorta diameters, cardiac interventions, adverse outcomes, recommended follow-up interval, and frequency of cardiac imaging studies at each follow up evaluation, as well as AS/AR severity at final evaluation. Outcomes were analyzed using generalized mixed-effect models with subject and provider clustering.

RESULTS

BAV disease progression was evaluated in 294 subjects over 4.1 ± 2.4 (range 0.2-9.5) years. Ascending aorta z-scores increased by 0.1/year (P < .001) but aortic root diameter z-scores were unchanged. AS and/or AR progressed to >mild in 9 (3%), 1 subject underwent cardiac intervention, and none had a major complication. Management was evaluated in 454 subjects (1343 encounters) with 27 different cardiologists. The average recommended follow-up interval was 1.5 ± 0.9 years. Younger age at diagnosis, greater aortic root or ascending aorta z-score at diagnosis, ≥mild AS/AR at follow-up, and earlier diagnosis era were associated with shorter recommended follow-up interval (P < .001 for all). Imaging was obtained at 87% of follow-up encounters and was associated with age at encounter with children ≥12 years most frequently imaged (P < .001). Provider accounted for 14% of variability in recommended follow-up interval and 24% of imaging variability (P < .001 for both).

CONCLUSIONS

We found little to no evidence of disease progression in children with an isolated BAV. Given the low risk, close follow-up and frequent cardiac imaging for BAV surveillance may not be warranted for children.

Longitudinal Outcomes of Patients With Single Ventricle After the Fontan Procedure

BACKGROUND

Multicenter longitudinal objective data for survival into adulthood of patients who have undergone Fontan procedures are lacking.

OBJECTIVES

This study sought to describe transplant-free survival and explore relationships between laboratory measures of ventricular performance and functional status over time.

METHODS

Exercise testing, echocardiography, B-type natriuretic peptide, functional health assessment, and medical history abstraction were repeated 9.4 ± 0.4 years after the Fontan Cross-Sectional Study (Fontan 1) and compared with previous values. Cox regression analysis explored risk factors for interim death or cardiac transplantation.

RESULTS

From the original cohort of 546 subjects, 466 were contacted again, and 373 (80%) were enrolled at 21.2 ± 3.5 years of age. Among subjects with paired testing, the percent predicted maximum oxygen uptake decreased (69 ± 14% vs. 61 ± 16%; p < 0.001; n = 95), ejection fraction decreased (58 ± 11% vs. 55 ± 10%; p < 0.001; n = 259), and B-type natriuretic peptide increased (median [interquartile range] 13 [7 to 25] pg/mol vs. 18 [9 to 36] pg/mol; p < 0.001; n = 340). At latest follow-up, a lower Pediatric Quality of Life Inventory physical summary score was associated with poorer exercise performance (R² adjusted = 0.20; p < 0.001; n = 274). Cumulative complications since the Fontan procedure included additional cardiac surgery (32%), catheter intervention (62%), arrhythmia treatment (32%), thrombosis (12%), and protein-losing enteropathy (8%). Since Fontan 1, 54 subjects (10%) have received a heart transplant (n = 23) or died without transplantation (n = 31). The interval risk of death or/cardiac transplantation was associated with poorer ventricular performance and functional health status assessed at Fontan 1, but it was not associated with ventricular morphology, the subject's age, or the type of Fontan connection.

CONCLUSIONS

Interim transplant-free survival over 12 years in this Fontan cohort was 90% and was independent of ventricular morphology. Exercise performance decreased and was associated with worse functional health status. Future interventions might focus on preserving exercise capacity. (Relationship Between Functional Health Status and Ventricular Performance After Fontan-Pediatric Heart Network; NCT00132782).

Use of Oxandrolone to Promote Growth in Neonates following Surgery for Complex Congenital Heart Disease: An Open-Label Pilot Trial

OBJECTIVE

Malnutrition and poor weight gain, common in neonates following repair of complex congenital heart disease (CHD), are associated with increased morbidity and mortality. Oxandrolone, an anabolic steroid, improves weight gain in older children at high-risk for growth failure. We sought to determine feasibility, safety, and efficacy of oxandrolone therapy in neonates following surgery for complex CHD.

DESIGN

Neonates with RACHS-1 score >3 were eligible to receive open-label oxandrolone for 28 days in this prospective pilot trial. There were 3 cohorts of 5 subjects receiving oxandrolone therapy under 3 specified dosage and preparation protocols: 0.1 mg/kg/day aqueous solution, 0.2 mg/kg/day aqueous solution, and 0.1 mg/kg/day preparation in medium chain triglyceride (MCT) oil. Age- and diagnosis-matched neonates who underwent surgery, but received no oxandrolone, served as a control cohort. Anthropometric measurements, physical examination for virilization, safety labs, and adverse events were monitored.

RESULTS

Of 25 eligible patients, 15 consented (60%, 13/15 with Norwood procedure). There was no evidence of virilization, no changes in safety labs, and no serious adverse events related to oxandrolone among subjects receiving therapy. No subject met criteria for termination of study drug. There was a significant difference in change in weight-for-age z-score among the four cohorts, with subjects receiving 0.1 mg/kg/day in MCT oil having the lowest decline during the study period (-1.8 ± 0.5 for controls, -1.7 ± 0.4 for 0.1 mg/kg/day aqueous, -1.0 ± 0.4 for 0.2 mg/kg/day aqueous, and -0.6 ± 0.7 for 0.1 mg/kg/day MCT oil, P = .012).

CONCLUSIONS

Oxandrolone therapy at the doses studied appears safe in neonates after surgery for complex CHD. The decline in weight-for-age z-score was lowest in those receiving the MCT oil preparation suggesting better bioavailability of this preparation and a potential growth benefit with oxandrolone therapy. Further investigation is needed to define optimal dosing and assess efficacy.

Novel Cardiac Magnetic Resonance Feature Tracking (CMR-FT) Analysis for Detection of Myocardial Fibrosis in Pediatric Hypertrophic Cardiomyopathy

Myocardial fibrosis is a risk factor for sudden cardiac death in hypertrophic cardiomyopathy (HCM) and is conventionally identified by cardiac magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE). This study evaluates utility of a novel 16-segment CMR feature tracking (CMR-FT) technique for measuring left ventricular (LV) strain (S) and strain rate (SR) on non-contrast cine images to detect myocardial fibrosis in pediatric HCM. We hypothesized that CMR-FT-derived S and SR will accurately differentiate HCM patients with and without myocardial fibrosis. Consecutive children with HCM who underwent CMR with LGE at our institution from 2006 to 2014 were included. Global and regional longitudinal, radial and circumferential S and SR of the LV in 2D and 3D were obtained using a CMR-FT software. Comparisons were made between HCM patients with (+LGE) and without (-LGE) delayed enhancement. Of the 29 HCM patients (mean age 13.5 ± 6.1 years; 52 % males), 11 (40 %) patients (mean age 17.5 ± 8.4 years) had +LGE. Global longitudinal, circumferential and radial S and SR were lower in +LGE compared to -LGE patients, in both 2D and 3D. Regional analysis revealed lower segmental S and SR in the septum with fibrosis compared to free wall without fibrosis. A global longitudinal S of ≤ -12.8 had 91 % sensitivity and 89 % specificity for detection of LGE. In pediatric HCM patients with myocardial fibrosis, global LV longitudinal, circumferential and radial S and SR were reduced, specifically in areas of fibrosis. A global longitudinal S of ≤ -12.8 detected patients with fibrosis with high degree of accuracy. This novel CMR-FT technique may be useful to identify myocardial fibrosis and risk-stratify pediatric HCM without use of contrast agents.

Predicting skin sensitisation using a decision tree integrated testing strategy with an in silico model and in chemico/in vitro assays

There is a pressing need for non-animal methods to predict skin sensitisation potential and a number of in chemico and in vitro assays have been designed with this in mind. However, some compounds can fall outside the applicability domain of these in chemico/in vitro assays and may not be predicted accurately. Rule-based in silico models such as Derek Nexus are expert-derived from animal and/or human data and the mechanism-based alert domain can take a number of factors into account (e.g. abiotic/biotic activation). Therefore, Derek Nexus may be able to predict for compounds outside the applicability domain of in chemico/in vitro assays. To this end, an integrated testing strategy (ITS) decision tree using Derek Nexus and a maximum of two assays (from DPRA, KeratinoSens, LuSens, h-CLAT and U-SENS) was developed. Generally, the decision tree improved upon other ITS evaluated in this study with positive and negative predictivity calculated as 86% and 81%, respectively. Our results demonstrate that an ITS using an in silico model such as Derek Nexus with a maximum of two in chemico/in vitro assays can predict the sensitising potential of a number of chemicals, including those outside the applicability domain of existing non-animal assays.

Growth Asymmetry, Head Circumference, and Neurodevelopmental Outcomes in Infants with Single Ventricles

OBJECTIVE

To assess the variability in asymmetric growth and its association with neurodevelopment in infants with single ventricle (SV).

STUDY DESIGN

We analyzed weight-for-age z-score minus head circumference-for-age z-score (HCAZ), relative head growth (cm/kg), along with individual growth variables in subjects prospectively enrolled in the Infant Single Ventricle Trial. Associations between growth indices and scores on the Psychomotor Developmental Index (PDI) and Mental Developmental Index (MDI) of the Bayley Scales of Infant Development-II (BSID-II) at 14 months were assessed.

RESULTS

Of the 230 subjects enrolled in the Infant Single Ventricle trial, complete growth data and BSID-II scores were available in 168 (73%). Across the cohort, indices of asymmetric growth varied widely at enrollment and before superior cavopulmonary connection (SCPC) surgery. BSID-II scores were not associated with these asymmetry indices. In bivariate analyses, greater pre-SCPC HCAZ correlated with higher MDI (r = 0.21; P = .006) and PDI (r = 0.38; P < .001) and a greater HCAZ increase from enrollment to pre-SCPC with higher PDI (r = 0.15; P = .049). In multivariable modeling, pre-SCPC HCAZ was an independent predictor of PDI (P = .03), but not MDI.

CONCLUSION

In infants with SV, growth asymmetry was not associated with neurodevelopment at 14 months, but pre-SCPC HCAZ was associated with PDI. Asymmetric growth, important in other high-risk infants, is not a brain-sparing adaptation in infants with SV.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT00113087.

Modification of Hepatic Venous Conduit to Manage Pulmonary Arteriovenous Malformations

While the Fontan operation is a reliable treatment option for many complex congenital heart defects, the development of pulmonary arteriovenous malformations (PAVMs) remains a problematic outcome for some Fontan patients. Pulmonary arteriovenous malformations stem from an imbalance of hepatic blood flow in the pulmonary system. Balancing this hepatic flow has shown promising results in the treatment of PAVMs. We report the clinical course of a young patient with heterotaxy syndrome and an unbalanced right dominant atrioventricular septal defect. This patient developed PAVMs following a Fontan procedure, however, the PAVMs were resolved following the revision of the original Fontan conduit to a bifurcated conduit.

Quantitative Assay Validation for Oxandrolone in Human Plasma Using LC-MS-MS

A high-performance liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the determination of oxandrolone concentration in human plasma (0.5 mL) was developed and validated according to the 2001 FDA Bioanalytical Guidelines. Oxandrolone is an anabolic steroid used to promote weight gain for cachectic patients with severe burn injuries, HIV/AIDS, hepatitis C and other wasting syndromes. The assay procedure involved a liquid-liquid extraction of oxandrolone and methyltestosterone (the internal standard, IS) from plasma with n-butyl chloride. The organic layer was clarified by centrifugation and evaporated to dryness under a stream of air. The residue was reconstituted in a solution containing 25% methanol and 75% Milli-Q water, and injected onto a Luna C18 reversed-phase HPLC column (30 mm × 2.0 mm, 2 μm). Separation of oxandrolone and methyltestosterone was achieved with a mobile phase starting composition of 55% methanol and 45% ammonium formate buffer at a flow rate of 0.1 mL/min. The total run time was 21 min per sample. Selected reaction monitoring mode was used for quantifying oxandrolone (m/z 307 → 271) and the IS, methyltestosterone (m/z 301 → 149). To the authors' knowledge, this is the first LC-MS-MS method validated for oxandrolone quantification in human plasma. This method can be used in future pharmacokinetic studies involving oxandrolone.

Survival data and predictors of functional outcome an average of 15 years after the Fontan procedure: the pediatric heart network Fontan cohort

OBJECTIVE

Multicenter longitudinal outcome data for Fontan patients surviving into adulthood are lacking. The aim of this study was to better understand contemporary outcomes in Fontan survivors by collecting follow-up data in a previously well-characterized cohort.

DESIGN

Baseline data from the Fontan Cross-Sectional Study (Fontan 1) were previously obtained in 546 Fontan survivors aged 11.9 ± 3.4 years. We assessed current transplant-free survival status in all subjects 6.8 ± 0.4 years after the Fontan 1 study. Anatomic, clinical, and surgical data were collected along with socioeconomic status and access to health care.

RESULTS

Thirty subjects (5%) died or underwent transplantation since Fontan 1. Subjects with both an elevated (>21 pg/mL) brain natriuretic peptide and a low Child Health Questionnaire physical summary score (<44) measured at Fontan 1 were significantly more likely to die or undergo transplant than the remainder, with a hazard ratio of 6.2 (2.9-13.5). Among 516 Fontan survivors, 427 (83%) enrolled in this follow-up study (Fontan 2) at 18.4 ± 3.4 years of age. Although mean scores on functional health status questionnaires were lower than the general population, individual scores were within the normal range in 78% and 88% of subjects for the Child Health Questionnaire physical and psychosocial summary score, and 97% and 91% for the SF-36 physical and mental aggregate score, respectively. Since Fontan surgery, 119 (28%) had additional cardiac surgery; 55% of these (n = 66) in the interim between Fontan 1 and Fontan 2. A catheter intervention occurred in 242 (57%); 32% of these (n = 78) after Fontan 1. Arrhythmia requiring treatment developed in 118 (28%) after Fontan surgery; 58% of these (n = 68) since Fontan 1.

CONCLUSIONS

We found 95% interim transplant-free survival for Fontan survivors over an average of 7 years of follow-up. Continued longitudinal investigation into adulthood is necessary to better understand the determinants of long-term outcomes and to improve functional health status.

The relationship of patient medical and laboratory characteristics to changes in functional health status in children and adolescents after the Fontan procedure

Despite hypothesized concerns about deterioration beginning in adolescence, longitudinal data and associated factors regarding standardized assessment of physical functioning are not available for Fontan patients. Parents who participated in the Fontan Cross-Sectional Study completed the Child Health Questionnaire at 2 time points for 245 subjects ages 6-18 years. Associations between change in Physical Functioning Summary Score and baseline patient, medical, and laboratory characteristics (mean age 9.5 ± 1.7 years) and follow-up patient and medical characteristics (mean age 16.2 ± 1.6 years) were determined by regression analyses. During a mean of 6.7 ± 0.4 years, a small (not clinically important) but statistically significant decrease in score from 46.2 ± 11.7 to 44.5 ± 12.1 (p < 0.03) was noted. Subjects with higher baseline scores had a greater decrease in score (r = -0.48; p < 0.001). A multivariable model of patient and medical characteristics (R(2) = 0.11) showed that a greater decrease in score was significantly associated with interim development of asthma (n = 13; parameter estimate [PE] -6.6; p < 0.05) or other chronic respiratory, lung, or breathing problems (n = 13; PE -12.5; p < 0.001) and the presence of protein-losing enteropathy at any time (n = 12; PE -9.4; p = 0.006). Change in score was not significantly associated with baseline laboratory measures of exercise capacity and ventricular characteristics and function. Therefore, although physical functioning may be stable during adolescence for many Fontan patients, deterioration occurs in some in association with respiratory conditions and protein-losing enteropathy. Further longitudinal study is necessary to better understand the relationship between clinical morbidities and functional health status as these patients transition into adulthood.

Variation in feeding practices following the Norwood procedure

OBJECTIVES

To assess variation in feeding practice at hospital discharge after the Norwood procedure, factors associated with tube feeding, and associations among site, feeding mode, and growth before stage II.

STUDY DESIGN

From May 2005 to July 2008, 555 subjects from 15 centers were enrolled in the Pediatric Heart Network Single Ventricle Reconstruction Trial; 432 survivors with feeding data at hospital discharge after the Norwood procedure were analyzed.

RESULTS

Demographic and clinical variables were compared among 4 feeding modes: oral only (n = 140), oral/tube (n = 195), nasogastric tube (N-tube) only (n = 40), and gastrostomy tube (G-tube) only (n = 57). There was significant variation in feeding mode among sites (oral only 0%-81% and G-tube only 0%-56%, P < .01). After adjusting for site, multivariable modeling showed G-tube feeding at discharge was associated with longer hospitalization, and N-tube feeding was associated with greater number of discharge medications (R(2) = 0.65, P < .01). After adjusting for site, mean pre-stage II weight-for-age z-score was significantly higher in the oral-only group (-1.4) vs the N-tube-only (-2.2) and G-tube-only (-2.1) groups (P = .04 and .02, respectively).

CONCLUSIONS

Feeding mode at hospital discharge after the Norwood procedure varied among sites. Prolonged hospitalization and greater number of medications at the time of discharge were associated with tube feeding. Infants exclusively fed orally had a higher weight-for-age z score pre-stage II than those fed exclusively by tube. Exploring strategies to prevent morbidities and promote oral feeding in this highest risk population is warranted.

Factors impacting echocardiographic imaging after the Fontan procedure: a report from the pediatric heart network fontan cross-sectional study

Echocardiographic image quality in Fontan survivors may be limited by a variety of factors. We sought to describe echocardiographic quality and factors associated with study quality in subjects participating in the Pediatric Heart Network Fontan Cross-Sectional Study. Echocardiograms were obtained at 7 clinical sites using a standard protocol. Quality grading and analysis were performed by a core laboratory. Univariate and multivariable modeling were performed to assess factors associated with quality and ability to obtain images sufficient for prespecified quantitative analysis. A total of 543 echocardiograms were obtained. The quality of echocardiograms improved over the duration of the study. The great arteries, systemic veins, and pulmonary veins were less likely to be adequately imaged than other cardiac structures. Quantitative analysis of ventricular volume was possible in 76% overall, but only 41% of those with mixed ventricular morphology. Factors independently associated with better quality included younger age, levocardia, acquisition of the echocardiogram at a longer time since the beginning of enrollment, absence of a pulmonary artery stent, and clinical site. Patient and center-specific factors are associated with echocardiographic quality after the Fontan procedure. Increased familiarity and experience with a standard imaging protocol is likely to result in improved quality.

Comparison of Fontan survivors with and without pacemakers: a report from the Pediatric Heart Network Fontan Cross-Sectional Study

OBJECTIVE

Although many Fontan patients undergo pacemaker placement, there are few studies characterizing this population. Our purpose was to compare clinical characteristics, functional status and measures of ventricular performance in Fontan patients with and without a pacemaker.

PATIENTS AND DESIGN

The National Heart, Lung, and Blood Institute funded Pediatric Heart Network Fontan Cross-Sectional Study characterized 546 Fontan survivors. Clinical characteristics, medical history and study outcomes (Child Health Questionnaire [CHQ]), echocardiographic evaluation of ventricular function, and exercise testing) were compared between subjects with and without pacemakers.

RESULTS

Of 71 subjects with pacemakers (13%), 43/71 (61%) were in a paced rhythm at the time of study enrollment (age 11.9 ± 3.4 years). Pacemaker subjects were older at study enrollment, more likely to have single left ventricles, and taking more medications. There were no differences in age at Fontan or Fontan type between the pacemaker and no pacemaker groups. There were no differences in exercise performance between groups. CHQ physical summary scores were lower in the pacemaker subjects (39.7 ± 14.3 vs. 46.1 ± 11.2, P =.001). Ventricular ejection fraction z-score was also lower (-1.4 ± 1.9 vs. -0.8 ± 2.0, P =.05) in pacemaker subjects.

CONCLUSIONS

In our cohort of Fontan survivors, those with a pacemaker have poorer functional status and evidence of decreased ventricular systolic function compared to Fontan survivors without a pacemaker.

Factors affecting growth in infants with single ventricle physiology: a report from the Pediatric Heart Network Infant Single Ventricle Trial

OBJECTIVES

To describe growth patterns in infants with single ventricle physiology and determine factors influencing growth.

STUDY DESIGN

Data from 230 subjects enrolled in the Pediatric Heart Network Infant Single Ventricle Enalapril Trial were used to assess factors influencing change in weight-for-age z-score (z) from study enrollment (0.7 ± 0.4 months) to pre-superior cavopulmonary connection (SCPC; 5.1 ± 1.8 months, period 1) and pre-SCPC to final study visit (14.1 ± 0.9 months, period 2). Predictor variables included patient characteristics, feeding regimen, clinical center, and medical factors during neonatal (period 1) and SCPC hospitalizations (period 2). Univariate regression analysis was performed, followed by backward stepwise regression and bootstrapping reliability to inform a final multivariable model.

RESULTS

Weights were available for 197 of 230 subjects for period 1 and 173 of 197 subjects for period 2. For period 1, greater gestational age, younger age at study enrollment, tube feeding at neonatal hospitalization discharge, and clinical center were associated with a greater negative z (poorer growth) in multivariable modeling (adjusted R(2) = 0.39, P < .001). For period 2, younger age at SCPC and greater daily caloric intake were associated with greater positive z (better growth; R(2) = 0.10, P = .002).

CONCLUSIONS

Aggressive nutritional support and earlier SCPC are modifiable factors associated with a favorable change in weight-for-age z-score.

The Fontan patient: inconsistencies in medication therapy across seven pediatric heart network centers

Patients who have undergone the Fontan procedure are at risk for thrombosis, ventricular dysfunction, and valve regurgitation, but data to guide the medical treatment and prevention of these adverse outcomes in this population are lacking. This analysis examined medication usage among Fontan patients by putative indication and by study center. The medical history and current medications of 546 Fontan subjects, ages 6-18 years, were assessed in a Pediatric Heart Network multicenter cross-sectional study. Cardiac imaging was performed within 3 months of enrollment. The majority of the subjects (64%) were taking two or more medications. Antithrombotics were taken by 86% of those with a history of stroke, thrombosis, or both and 67% of those without such a history (P = 0.01). Conversely, 14% of those with a history of stroke, thrombosis, or both were taking no antithrombotic. Angiotensin-converting enzyme inhibitor (ACEi) therapy was independently associated with moderate or severe atrioventricular valve regurgitation (P = 0.004), right ventricular morphology (P < 0.001), and shorter time since Fontan (P = 0.004) but not with ventricular systolic dysfunction. Glycoside therapy and diuretic therapy each was associated with older age at Fontan (P = 0.001 and P = 0.023, respectively) and a history of post-Fontan arrhythmia (P < 0.001 and P = 0.003, respectively) but not with ventricular systolic dysfunction. Medication use rates varied widely among the centers, even with controls for center differences in patient characteristics. Prospective therapeutic trials are needed to guide the medical treatment of Fontan patients.

Birth weight and prematurity in infants with single ventricle physiology: pediatric heart network infant single ventricle trial screened population

OBJECTIVES

Although congenital heart disease is associated with low birth weight and prematurity, there is little information about these birth outcomes in infants with single ventricle physiology. We describe the birth outcomes (i.e., gestational age and birth weight) in neonates with single ventricle physiology screened for enrollment in the Pediatric Heart Network's Infant Single Ventricle Trial, compare these outcomes with US norms, and examine the association of birth outcomes with anatomic diagnosis and race.

PATIENTS AND METHODS

All neonates with single ventricle physiology presenting to Infant Single Ventricle Trial centers were screened for enrollment. Demographic data and anatomic diagnoses were obtained from medical records.

RESULTS

A total of 1245 neonates with single ventricle physiology were screened at 10 centers (63 to 266 per center). Diagnoses included hypoplastic left heart syndrome in 49%, unbalanced atrioventricular septal defect in 12%, and tricuspid atresia in 9%. Preterm birth occurred in 16% of neonates with single ventricle physiology vs. 12% in normal neonates (P < .001), low birth weight (<2.5 kg) in 18% vs. 8% in normals (P < .001), and small for gestational age (<10th percentile by definition) in 22% vs. 10% in normals (P < .001). A genetic syndrome was reported in 8%. The percentage of preterm birth, low birth weight, and small for gestational age was similar between screened neonates with and without hypoplastic left heart syndrome.

CONCLUSIONS

In this large, contemporary cohort of neonates with single ventricle physiology, rates of preterm birth, low birth weight, and small for gestational age were higher than in the general population, but similar between screened neonates with and without hypoplastic left heart syndrome.

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

BACKGROUND

Angiotensin-converting enzyme inhibitor therapy improves clinical outcome and ventricular function in adults with heart failure. Infants with single-ventricle physiology have poor growth and are at risk for abnormalities in ventricular systolic and diastolic function. The ability of angiotensin-converting enzyme inhibitor therapy to preserve ventricular function and improve somatic growth and outcomes in these infants is unknown.

METHODS AND RESULTS

The Pediatric Heart Network conducted a double-blind trial involving 230 infants with single-ventricle physiology randomized to receive enalapril (target dose 0.4 mg . kg(-1) . d(-1)) or placebo who were followed up until 14 months of age. The primary end point was weight-for-age z score at 14 months. The primary analysis was intention to treat. A total of 185 infants completed the study. There were 24 and 21 withdrawals or deaths in the enalapril and placebo groups, respectively (P=0.74). Weight-for-age z score was not different between the enalapril and placebo groups (mean+/-SE -0.62+/-0.13 versus -0.42+/-0.13, P=0.28). There were no significant group differences in height-for-age z score, Ross heart failure class, brain natriuretic peptide concentration, Bayley scores of infant development, or ventricular ejection fraction. The incidence of death or transplantation was 13% and did not differ between groups. Serious adverse events occurred in 88 patients in the enalapril group and 87 in the placebo group.

CONCLUSIONS

Administration of enalapril to infants with single-ventricle physiology in the first year of life did not improve somatic growth, ventricular function, or heart failure severity. The results of this randomized trial do not support the routine use of enalapril in this population.

Does abciximab promote coronary artery remodeling in patients with Kawasaki disease?

Standard therapy, consisting of intravenous immunoglobulin and aspirin, reduces, but does not eliminate, coronary artery aneurysms (CAAs) in patients with Kawasaki disease. Large CAAs can persist or undergo varying degrees of regression. The treatment of large CAAs using abciximab has been associated with short-term regression; however, longer term data are unavailable. We sought to obtain longer term follow-up data regarding the changes in the diameters of large CAAs in patients receiving both abciximab and standard therapy and to compare these changes to those of a similar group receiving standard therapy alone. All patients with Kawasaki disease and large CAAs (diameter >5 mm or Z score >10) treated from 1986 to 2007 were identified and divided into 2 groups. The abciximab group received abciximab plus standard therapy and the no-abciximab group received standard therapy alone. The maximum diameters of the proximal right and left anterior descending CAAs were obtained from echocardiograms. The Z scores were calculated for 3 points: the acute/subacute phase (<8 weeks) and at 1 and 3 to 5 years of follow-up. The patients in the abciximab (n = 11) and no-abciximab (n = 7) groups were similar in age, interval to treatment, gender, and largest CAA Z score at diagnosis (19.6 +/- 6.2 vs 25.8 +/- 9.5, p = 0.11). The change in CAA Z score was similar between the 2 groups at 1 year (p = 0.99). At 3 to 5 years of follow-up, compared to baseline, the abciximab group had a greater decrease in the CAA Z score than did the no-abciximab group (-14.0 +/- 4.0 vs -8.2 +/- 5.9, p = 0.04). In conclusion, abciximab treatment might be associated with vascular remodeling in patients with large CAAs.

Laboratory measures of exercise capacity and ventricular characteristics and function are weakly associated with functional health status after Fontan procedure

BACKGROUND

Patients after the Fontan procedure are at risk for suboptimal functional health status, and associations with laboratory measures are important for planning interventions and outcome measures for clinical trials.

METHODS AND RESULTS

Parents completed the generic Child Health Questionnaire for 511 Fontan Cross-Sectional Study patients 6 to 18 years of age (61% male). Associations of Child Health Questionnaire Physical and Psychosocial Functioning Summary Scores (FSS) with standardized measurements from prospective exercise testing, echocardiography, magnetic resonance imaging, and measurement of brain natriuretic peptide were determined by regression analyses. For exercise variables for maximal effort patients only, the final model showed that higher Physical FSS was associated only with higher maximum work rate, accounting for 9% of variation in Physical FSS. For echocardiography, lower Tei index (particularly for patients with extracardiac lateral tunnel connections), lower indexed end-systolic volume, and the absence of atrioventricular valve regurgitation for patients having Fontan procedure at age <2 years were associated with higher Physical FSS, accounting for 14% of variation in Physical FSS. For magnetic resonance imaging, ratio of lower mass to end-diastolic volume and midquartiles of indexed end-systolic volume (nonlinear) were associated with higher Physical FSS, accounting for 11% of variation. Lower brain natriuretic peptide was significantly but weakly associated with higher Physical FSS (1% of variation). Significant associations for Psychosocial FSS with laboratory measures were fewer and weaker than for Physical FSS.

CONCLUSIONS

In relatively healthy Fontan patients, laboratory measures account for a small proportion of the variation in functional health status and therefore may not be optimal surrogate end points for trials of therapeutic interventions.

Noninvasive assessment of subclinical atherosclerosis in children and adolescents: recommendations for standard assessment for clinical research: a scientific statement from the American Heart Association

Deterioration in endothelial function and arterial stiffness are early events in the development of cardiovascular diseases. In adults, noninvasive measures of atherosclerosis have become established as valid and reliable tools for refining cardiovascular risk to target individuals who need early intervention. With limited pediatric data, the use of these techniques in children and adolescents largely has been reserved for research purposes. Therefore, this scientific statement was written to (1) review the current literature on the noninvasive assessment of atherosclerosis in children and adolescents, (2) make recommendations for the standardization of these tools for research, and (3) stimulate further research with a goal of developing valid and reliable techniques with normative data for noninvasive clinical evaluation of atherosclerosis in pediatric patients. Precise and reliable noninvasive tests for atherosclerosis in youth will improve our ability to estimate future risk for heart attack and stroke. Currently, large longitudinal studies of cardiovascular risk factors in youth, such as the Bogalusa and Muscatine studies, lack sufficient adult subjects experiencing hard outcomes, such as heart attack and stroke, to produce meaningful risk scores like those developed from Framingham data.

Rationale and design of a trial of angiotensin-converting enzyme inhibition in infants with single ventricle

BACKGROUND

Angiotensin converting enzyme (ACE) inhibitors are known to improve clinical outcome and ventricular function in adults with heart failure. Infants with single-ventricle physiology show abnormalities in ventricular function as well as poor growth. The ability of an ACE inhibitor to preserve ventricular function and improve growth in these infants is unknown.

METHODS

The Pediatric Heart Network designed a randomized, double-blind trial to compare outcomes in infants with single-ventricle physiology receiving enalapril or placebo. Neonates < or =45 days old were eligible. The primary outcome is weight-for-age Z-score at 14 months of age. Secondary outcomes include other measures of somatic growth, laboratory and functional measures of heart failure, developmental indices, measures of ventricular size and function, and the relationship of the renin-angiotensin-aldosterone system genotype to the response to enalapril. The incidence and spectrum of adverse events will also be compared between treatment groups.

RESULTS

A total of 1,245 neonates were screened and 533 (43%) were eligible. The consent rate was 43%; 230 subjects were enrolled. Parental reluctance to participate was the primary reason for non-consent in 79% of the eligible nonconsenting patients. Randomized patients were older, more likely to be male, and more likely to have hypoplastic left heart syndrome than the eligible patients who did not enroll.

CONCLUSIONS

The results of this randomized trial will make an important contribution to the management of infants with single-ventricle physiology by determining whether initiation of ACE inhibition therapy in the neonatal period improves growth, clinical outcome, and ventricular function.

Late gadolinium enhancement: precursor to cardiomyopathy in Duchenne muscular dystrophy?

BACKGROUND

Progressive cardiomyopathy is a common cause of death in Duchenne muscular dystrophy (DMD), presumably secondary to fibrosis of the myocardium. The posterobasal and left lateral free wall of the left ventricle (LV) are initial sites of myocardial fibrosis pathologically. The purposes of this study were to assess whether cardiac magnetic resonance imaging (CMRI), utilizing late gadolinium enhancement (LGE), could identify fibrosis in selective areas of the myocardium, and to assess the relationship of the presence and extent of fibrosis to LV function.

METHODS

The cardiology databases at Primary Children's Medical Center and Cincinnati Children's Hospital Medical Center were reviewed to identify patients with DMD who had undergone a CMRI within the last 2 years. Age, LV ejection fraction, LV mass, presence and location of LGE were documented. Volumes were measured using MASS (Medis, Inc.) to calculate ejection fraction and mass. LGE images were acquired and when positive, customized computer assisted sizing of the areas of late gadolinium enhancement were performed on all slices. Normal function was defined as LV ejection fraction >54%.

RESULTS

A total of 74 patients with DMD had complete data sets (median age 13.7 years, range 7.7-26.4). Twenty-four patients (32%) had LGE involving the posterobasal region of the LV in a sub-epicardial distribution. Those patients with more involvement had spread to the inferior and left lateral free wall with progressive transmural fibrous replacement. There was relative sparing of the interventricular septum and right ventricle. Patients with LGE were significantly older than those without (mean age 16.4 vs 12.9 years, P < 0.001). LGE was positively associated with BSA-adjusted LV mass, LV end-diastolic volume, LV end-systolic volume, and RV end-systolic volume but inversely correlated with ejection fraction of the LV (P < 0.001) and RV (P = 0.004).

CONCLUSIONS

LGE by CMRI is able to detect fibrosis in selective regions of myocardium in patients with DMD. Unfavorable LV remodeling, with a corresponding decreased ejection fraction, is associated with the presence of LGE. Serial studies are warranted to determine if LGE precedes a decrease in function, and if early medical management is useful in preventing progression once LGE is documented.

Contemporary outcomes after the Fontan procedure: a Pediatric Heart Network multicenter study

OBJECTIVES

We characterized a large cohort of children who had a Fontan procedure, with measures of functional health status, ventricular size and function, exercise capacity, heart rhythm, and brain natriuretic peptide (BNP).

BACKGROUND

The characteristics of contemporary Fontan survivors are not well described.

METHODS

We enrolled 546 children (age 6 to 18 years, mean 11.9 years) and compared them within pre-specified anatomic and procedure subgroups. History and outcome measures were obtained within a 3-month period.

RESULTS

Predominant ventricular morphology was 49% left ventricular (LV), 34% right ventricular (RV), and 19% mixed. Ejection fraction (EF) was normal for 73% of subjects; diastolic function grade was normal for 28%. Child Health Questionnaire mean summary scores were lower than for control subjects; however, over 80% of subjects were in the normal range. Brain natriuretic peptide concentration ranged from <4 to 652 pg/ml (median 13 pg/ml). Mean percent predicted peak O2 consumption was 65% and decreased with age. Ejection fraction and EF Z score were lowest, and semilunar and atrioventricular (AV) valve regurgitation were more prevalent in the RV subgroup. Older age at Fontan was associated with more severe AV valve regurgitation. Most outcomes were not associated with a superior cavopulmonary connection before Fontan.

CONCLUSIONS

Measures of ventricular systolic function and functional health status, although lower on average in the cohort compared with control subjects, were in the majority of subjects within 2 standard deviations of the mean for control subjects. Right ventricular morphology was associated with poorer ventricular and valvular function. Effective strategies to preserve ventricular and valvular function, particularly for patients with RV morphology, are needed.