Dysregulation of platelet serotonin, 14-3-3, and GPIX in sudden infant death syndrome.

Sudden infant death syndrome (SIDS) is the leading cause of post-neonatal infant mortality, but the underlying cause(s) are unclear. A subset of SIDS infants has abnormalities in the neurotransmitter, serotonin (5-hydroxytryptamine [5-HT]) and the adaptor molecule, 14-3-3 pathways in regions of the brain involved in gasping, response to hypoxia, and arousal. To evaluate our hypothesis that SIDS is, at least in part, a multi-organ dysregulation of 5-HT, we examined whether blood platelets, which have 5-HT and 14-3-3 signaling pathways similar to brain neurons, are abnormal in SIDS. We also studied platelet surface glycoprotein IX (GPIX), a cell adhesion receptor which is physically linked to 14-3-3. In infants dying of SIDS compared to infants dying of known causes, we found significantly higher intra-platelet 5-HT and 14-3-3 and lower platelet surface GPIX. Serum and plasma 5-HT were also elevated in SIDS compared to controls. The presence in SIDS of both platelet and brainstem 5-HT and 14-3-3 abnormalities suggests a global dysregulation of these pathways and the potential for platelets to be used as a model system to study 5-HT and 14-3-3 interactions in SIDS. Platelet and serum biomarkers may aid in the forensic determination of SIDS and have the potential to be predictive of SIDS risk in living infants.

A prospective multicenter feasibility study of a miniaturized implantable continuous flow ventricular assist device in smaller children with heart failure.

BACKGROUND: There is no FDA-approved left ventricular assist device (LVAD) for smaller children permitting routine hospital discharge. Smaller children supported with LVADs typically remain hospitalized for months awaiting heart transplant-a major burden for families and a challenge for hospitals. We describe the initial outcomes of the Jarvik 2015, a miniaturized implantable continuous flow LVAD, in the NHLBI-funded Pumps for Kids, Infants, and Neonates (PumpKIN) study, for bridge-to-heart transplant. METHODS: Children weighing 8 to 30 kg with severe systolic heart failure and failing optimal medical therapy were recruited at 7 centers in the United States. Patients with severe right heart failure and single-ventricle congenital heart disease were excluded. The primary feasibility endpoint was survival to 30 days without severe stroke or non-operational device failure. RESULTS: Of 7 children implanted, the median age was 2.2 (range 0.7, 7.1) years, median weight 10 (8.2 to 20.7) kilograms; 86% had dilated cardiomyopathy; 29% were INTERMACS profile 1. The median duration of Jarvik 2015 support was 149 (range 5 to 188) days where all 7 children survived including 5 to heart transplant, 1 to recovery, and 1 to conversion to a paracorporeal device. One patient experienced an ischemic stroke on day 53 of device support in the setting of myocardial recovery. One patient required ECMO support for intractable ventricular arrhythmias and was eventually transplanted from paracorporeal biventricular VAD support. The median pump speed was 1600 RPM with power ranging from 1-4 Watts. The median plasma free hemoglobin was 19, 30, 19 and 30 mg/dL at 7, 30, 90 and 180 days or time of explant, respectively. All patients reached the primary feasibility endpoint. Patient-reported outcomes with the device were favorable with respect to participation in a full range of activities. Due to financial issues with the manufacturer, the study was suspended after consent of the eighth patient. CONCLUSION: The Jarvik 2015 LVAD appears to hold important promise as an implantable continuous flow device for smaller children that may support hospital discharge. The FDA has approved the device to proceed to a 22-subject pivotal trial. Whether this device will survive to commercialization remains unclear because of the financial challenges faced by industry seeking to develop pediatric medical devices. (Supported by NIH/NHLBI HHS Contract N268201200001I, clinicaltrials.gov 02954497).

Erector spinae plane blocks for opioid-sparing multimodal pain management after pediatric cardiac surgery.

OBJECTIVE: Peripheral regional anesthesia is proposed to enhance recovery. We sought to evaluate the efficacy of bilateral continuous erector spinae plane blocks (B-ESpB) for postoperative analgesia and the impact on recovery in children undergoing cardiac surgery. METHODS: Patients aged 2 through 17 years undergoing cardiac surgery in the enhanced recovery after cardiac surgery program were prospectively enrolled to receive B-ESpB at the end of the procedure, with continuous infusions via catheters postoperatively. Participants wore an activity monitor until discharge. B-ESpB patients were retrospectively matched with control patients in the enhanced recovery after cardiac surgery program. Outcomes of the matched clusters were compared using exact conditional logistic regression and generalized linear modeling. RESULTS: Forty patients receiving B-ESpB were matched to 78 controls. There were no major complications from the B-ESpB or infusions, and operating room time was longer by a median of 31 minutes. While blocks were infusing, patients with B-ESpB received fewer opioids in oral morphine equivalents than controls at 24 hours (0.60 ± 0.06 vs 0.78 ± 0.04 mg/kg; P = .02) and 48 hours (1.13 ± 0.08 vs 1.35 ± 0.06 mg/kg; P = .04), respectively. Both groups had low median pain scores per 12-hour period. There was no difference in early mobilization, length of stay, or complications. CONCLUSIONS: B-ESpBs are safe in children undergoing cardiac surgery. When performed as part of a multimodal pain strategy in an enhanced recovery after cardiac surgery program, pediatric patients with B-ESpB experience good pain control and require fewer opioids in the first 48 hours.

Cleft closure and other predictors of contemporary outcomes after atrioventricular canal repair in patients with parachute left atrioventricular valve.

OBJECTIVES: Parachute left atrioventricular valve (LAVV) complicates atrioventricular septal defect (AVSD) repair. We evaluate outcomes of AVSD patients with parachute LAVV and identify risk factors for adverse outcomes. METHODS: We evaluated all patients undergoing repair of AVSD with parachute LAVV from 2012 to 2021. The primary outcome was a composite of time-to-death, LAVV reintervention and development of greater than or equal to moderate LAVV dysfunction (greater than or equal to moderate LAVV stenosis and/or LAVV regurgitation). Event-free survival for the composite outcome was estimated using Kaplan-Meier methodology and competing risks analysis. Cox proportional hazards regression was used to identify predictors of the primary outcome. RESULTS: A total of 36 patients were included with a median age at repair of 4 months (interquartile range 2.3-5.5 months). Over a median follow-up of 2.6 years (interquartile range 1.0-5.6 years), 6 (17%) patients underwent LAVV reintervention. All 6 patients who underwent LAVV reintervention had right-dominant AVSD. Sixteen patients (44%) met the composite outcome, and all did so within 2 years of initial repair. Transitional AVSD (versus complete), prior single-ventricle palliation, leaving the cleft completely open and greater than or equal to moderate preoperative LAVV regurgitation were associated with a higher risk of LAVV reintervention in univariate analysis. In multivariate analysis, leaving the cleft completely open was associated with the composite outcome. CONCLUSIONS: Repair of AVSD with parachute LAVV remains a challenge with a significant burden of LAVV reintervention and dysfunction in medium-term follow-up. Unbalanced, right-dominant AVSDs are at higher risk for LAVV reintervention. Leaving the cleft completely open might independently predict poor overall outcomes and should be avoided when possible. CLINICAL TRIAL REGISTRATION NUMBER: IRB-P00041642.

Mitral valve orifice area predicts outcome after biventricular repair in patients with hypoplastic left ventricles.

BACKGROUND: Identification of risk factors for biventricular (BiV) repair in children with hypoplastic left ventricles (HLV) has been challenging. We sought to identify preoperative cardiovascular magnetic resonance (CMR) predictors of outcome in patients with HLVs who underwent BiV repair, with a focus on the mitral valve (MV). METHODS: Single-center retrospective analysis of preoperative CMRs on patients with HLV (≤50 mL/m2) and no endocardial fibroelastosis who underwent BiV repair from 2005-2022. CMR measurements included MV orifice area in diastole. The primary composite outcome included time to death, transplant, BiV takedown, heart failure admission, left atrial decompression, or unexpected reoperation; and the secondary outcome included more than or equal to moderate mitral stenosis and/or regurgitation. RESULTS: Median follow-up was 0.7 (interquartile range 0.1, 2.2) years. Of 122 patients [59 atrioventricular canal (AVC) and 63 non-AVC] age 3 ± 2.8 years at the time of BiV repair, freedom from the primary outcome at 2 years was 53% for AVC and 69% for non-AVC (log rank p = 0.12), and freedom from the secondary outcome at 2 years was 49% for AVC and 79% for non-AVC (log rank p < 0.01). Independent predictors of primary outcome for AVC patients included MV orifice area z-score <-2 and transitional AVC; for non-AVC patients, predictors included MV orifice area z-score <-2, abnormal MV anatomy, and conal-septal ventricular septal defect. Independent predictors of secondary outcome for AVC patients included older age at surgery, transitional AVC, and transposition of the great arteries. CONCLUSION: In children with HLV, low MV orifice area and pre-existing MV pathology are risk factors for adverse outcome after BiV repair.

The experience of fathers of children hospitalised with advanced heart disease.

BACKGROUND: There are little reported data on the perspectives of fathers caring for children with chronic conditions. Although survival of children with advanced heart disease has improved, long-term morbidity remains high. This study describes the experience and prognostic awareness of fathers of hospitalised children with advanced heart disease. METHODS: Cross-sectional survey study of parents caring for children hospitalised with advanced heart disease admitted for ≥ 7 days over a one-year period. One parent per patient completed surveys, resulting in 27 father surveys. Data were analysed using descriptive methods. RESULTS: Nearly all (96%) of the fathers reported understanding their child's prognosis "extremely well" or "well," and 59% felt they were "very prepared" for their child's medical problems. However, 58% of fathers wanted to know more about prognosis, and 22% thought their child's team knew something about prognosis that they did not. Forty-one per cent of fathers did not think that their child would have lifelong limitations, and 32% anticipated normal life expectancies. All 13 fathers who had a clinical discussion of what would happen if their child got sicker found this conversation helpful. Nearly half (43%) of the fathers receiving new prognostic information or changes to treatment course found it "somewhat" or "a little" confusing. CONCLUSIONS: Fathers report excellent understanding of their child's illness and a positive experience around expressing their hopes and fears. Despite this, there remain many opportunities to improve communication, prognostic awareness, and participation in informed decision-making of fathers of children hospitalised with advanced heart disease.

Multiomic Analysis of Neuroinflammation and Occult Infection in Sudden Infant Death Syndrome.

Importance: Antemortem infection is a risk factor for sudden infant death syndrome (SIDS)-the leading postneonatal cause of infant mortality in the developed world. Manifestations of infection and inflammation are not always apparent in clinical settings or by standard autopsy; thus, enhanced resolution approaches are needed. Objective: To ascertain whether a subset of SIDS cases is associated with neuroinflammation and occult infection. Design, Setting, and Participants: In this case-control study, postmortem fluids from SIDS cases and controls collected between July 2011 and November 2018 were screened for elevated inflammatory markers, specifically cerebrospinal fluid (CSF) neopterin and CSF and serum cytokines. CSF, liver, and brain tissue from SIDS cases with elevated CSF neopterin were subjected to metagenomic next-generation sequencing (mNGS) to probe for infectious pathogens. Brainstem tissue from a subset of these cases was analyzed by single-nucleus RNA sequencing (snRNAseq) to measure cell type-specific gene expression associated with neuroinflammation and infection. All tissue and fluid analyses were performed from April 2019 to January 2023 in a pathology research laboratory. Included was autopsy material from infants dying of SIDS and age-matched controls dying of known causes. Exposures: There were no interventions or exposures. Main Outcomes and Measures: CSF neopterin levels were measured by high-performance liquid chromatography. Cytokines were measured by multiplex fluorometric assay. mNGS was performed on liver, CSF, brain, and brainstem tissue. snRNAseq was performed on brainstem tissue. Results: A cohort of 71 SIDS cases (mean [SD] age, 55.2 [11.4] postconceptional weeks; 42 male [59.2%]) and 20 controls (mean [SD] age, 63.2 [16.9] postconceptional weeks; 11 male [55.0%]) had CSF and/or serum available. CSF neopterin was screened in 64 SIDS cases and 15 controls, with no exclusions. Tissues from 6 SIDS cases were further analyzed. For CSF neopterin measures, SIDS samples were from infants with mean (SD) age of 54.5 (11.3) postconceptional weeks (38 male [59.4%]) and control samples were from infants with mean (SD) age of 61.5 (17.4) postconceptional weeks (7 male [46.7%]). A total of 6 SIDS cases (9.3%) with high CSF neopterin were identified, suggestive of neuroinflammation. mNGS detected human parechovirus 3 (HPeV3) in tissue and CSF from 1 of these 6 cases. snRNAseq of HPeV3-positive brainstem tissue (medulla) revealed dramatic enrichment of transcripts for genes with predominately inflammatory functions compared with 3 age-matched SIDS cases with normal CSF neopterin levels. Conclusions and Relevance: Next-generation molecular tools in autopsy tissue provide novel insight into pathogens that go unrecognized by normal autopsy methodology, including in infants dying suddenly and unexpectedly.

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

OBJECTIVES: The routine use of stress ulcer prophylaxis (SUP) in infants with congenital heart disease (CHD) in the cardiac ICU (CICU) is controversial. We aimed to conduct a pilot study to explore the feasibility of performing a subsequent larger trial to assess the safety and efficacy of withholding SUP in this population (NCT03667703). DESIGN, SETTING, PATIENTS: Single-center, prospective, double-blinded, parallel group (SUP vs. placebo), pilot randomized controlled pilot trial (RCT) in infants with CHD admitted to the CICU and anticipated to require respiratory support for greater than 24 hours. INTERVENTIONS: Patients were randomized 1:1 (stratified by age and admission type) to receive a histamine-2 receptor antagonist or placebo until respiratory support was discontinued, up to 14 days, or transfer from the CICU, if earlier. MEASUREMENTS AND MAIN RESULTS: Feasibility was defined a priori by thresholds of screening rate, consent rate, timely drug allocation, and protocol adherence. The safety outcome was the rate of clinically significant upper gastrointestinal (UGI) bleeding. We screened 1,426 patients from February 2019 to March 2022; of 132 eligible patients, we gained informed consent in 70 (53%). Two patients did not require CICU admission after obtaining consent, and the remaining 68 patients were randomized to SUP (n = 34) or placebo (n = 34). Ten patients were withdrawn early, because of a change in eligibility (n = 3) or open-label SUP use (n = 7, 10%). Study procedures were completed in 58 patients (89% protocol adherence). All feasibility criteria were met. There were no clinically significant episodes of UGI bleeding during the pilot RCT. The percentage of patients with other nonserious adverse events did not differ between groups. CONCLUSIONS: Withholding of SUP in infants with CHD admitted to the CICU was feasible. A larger multicenter RCT designed to confirm the safety of this intervention and its impact on incidence of UGI bleeding, gastrointestinal microbiome, and other clinical outcomes is warranted.

The family burden of paediatric heart disease during the chronic phase of illness.

BACKGROUND: CHD is a lifelong condition with a significant burden of disease to patients and families. With increased survival, attention has shifted to longer-term outcomes, with a focus on social determinants of health. Among children with CHD, socioeconomic status is associated with disparities in outcomes. Household material hardship is a concrete measure of poverty and may serve as an intervenable measure of socioeconomic status. METHODS: A longitudinal survey study was conducted at multiple time points (at acute hospitalisation, then 12-24 months later in the chronic phase) to determine the prevalence of household material hardship among parents of children with advanced heart disease and quality of life during long-term follow-up. RESULTS: The analytic cohort was 160 children with a median patient age of 1 year (IQR 1,4) with 54% of patients <2 years. During acute hospitalisation, over one-third of families reported household material hardship (37%), with significantly lower household material hardship in the chronic phase at 16% (N = 9 of 52). For parents reporting household material hardship during acute hospitalisation, 50% had resolution of household material hardship by the chronic phase. Household material hardship-exposed children were significantly more likely to be publicly insured (56% versus 20%, p = 0.03) with lower quality of life than those without household material hardship (64% versus 82%, p = 0.013). CONCLUSION: The burden of heart disease during the chronic phase of illness is high. Household material hardship may serve as a target to ensure equity in the care and outcomes of CHD patients and their families.

Design and Harmonization Approach for the Multi-Institutional Neurocognitive Discovery Study (MINDS) of Adult Congenital Heart Disease (ACHD) Neuroimaging Ancillary Study: A Technical Note.

Dramatic advances in the management of congenital heart disease (CHD) have improved survival to adulthood from less than 10% in the 1960s to over 90% in the current era, such that adult CHD (ACHD) patients now outnumber their pediatric counterparts. ACHD patients demonstrate domain-specific neurocognitive deficits associated with reduced quality of life that include deficits in educational attainment and social interaction. Our hypothesis is that ACHD patients exhibit vascular brain injury and structural/physiological brain alterations that are predictive of specific neurocognitive deficits modified by behavioral and environmental enrichment proxies of cognitive reserve (e.g., level of education and lifestyle/social habits). This technical note describes an ancillary study to the National Heart, Lung, and Blood Institute (NHLBI)-funded Pediatric Heart Network (PHN) "Multi-Institutional Neurocognitive Discovery Study (MINDS) in Adult Congenital Heart Disease (ACHD)". Leveraging clinical, neuropsychological, and biospecimen data from the parent study, our study will provide structural-physiological correlates of neurocognitive outcomes, representing the first multi-center neuroimaging initiative to be performed in ACHD patients. Limitations of the study include recruitment challenges inherent to an ancillary study, implantable cardiac devices, and harmonization of neuroimaging biomarkers. Results from this research will help shape the care of ACHD patients and further our understanding of the interplay between brain injury and cognitive reserve.

Magnetic resonance three-dimensional steady-state free precession imaging of the thoracic duct in patients with Fontan circulation and its relationship to outcomes.

BACKGROUND: Lymphatic complications are common in patients with Fontan circulation. Three-dimensional balanced steady-state free precession (3D bSSFP) angiography by cardiovascular magnetic resonance (CMR) is widely used for cardiovascular anatomical assessment. We sought to determine the frequency of thoracic duct (TD) visualization using 3D bSSFP images and assess whether TD characteristics are associated with clinical outcomes. METHODS: This was a retrospective, single-center study of patients with Fontan circulation who underwent CMR. Frequency matching of age at CMR was used to construct a comparison group of patients with repaired tetralogy of Fallot (rTOF). TD characteristics included maximum diameter and a qualitative assessment of tortuosity. Clinical outcomes included protein-losing enteropathy (PLE), plastic bronchitis, listing for heart transplantation, and death. A composite outcome was defined as presence of any of these events. RESULTS: The study included 189 Fontan patients (median age 16.1 years, IQR 11.0-23.2 years) and 36 rTOF patients (median age 15.7 years, IQR 11.1-23.7 years). The TD diameter was larger (median 2.50 vs. 1.95 mm, p = 0.002) and more often well visualized (65% vs. 22%, p < 0.001) in Fontan patients vs. rTOF patients. TD dimension increased mildly with age in Fontan patients, R = 0.19, p = 0.01. In Fontan patients, the TD diameter was larger in those with PLE vs. without PLE (age-adjusted mean 4.11 vs. 2.72, p = 0.005), and was more tortuous in those with NYHA class ≥ II vs. class I (moderate or greater tortuosity 75% vs. 28.5%, p = 0.02). Larger TD diameter was associated with a lower ventricular ejection fraction that was independent of age (partial correlation = - 0.22, p = 0.02). More tortuous TDs had a higher end-systolic volume (mean 70.0 mL/m2 vs. 57.3 mL/m2, p = 0.03), lower creatinine (mean 0.61 mg/dL vs. 0.70 mg/dL, p = 0.04), and a higher absolute lymphocyte count (mean 1.80 K cells/µL vs. 0.76 K cells/µL, p = 0.003). The composite outcome was present in 6% of Fontan patients and was not associated with TD diameter (p = 0.50) or tortuosity (p = 0.09). CONCLUSIONS: The TD is well visualized in two-thirds of patients with Fontan circulation on 3D-bSSFP images. Larger TD diameter is associated with PLE and increased TD tortuosity is associated with an NYHA class ≥ II.

Impact of Right Ventricular Surface Area-to-Volume Ratio on Ventricular Remodeling After Pulmonary Valve Replacement.

Optimal reverse remodeling of the right ventricle (RV), a sentinel goal of pulmonary valve replacement (PVR) in patients with repaired tetralogy of Fallot, is not fully predicted by volume-based pre-PVR parameters. Our objectives were to characterize novel geometric RV parameters in patients receiving PVR and in controls, and to identify associations between these parameters and chamber remodeling post-PVR. Secondary analysis was performed on cardiac magnetic resonance (CMR) data from 60 patients enrolled in a randomized trial of PVR with and without surgical RV remodeling. 20 healthy age-matched subjects served as controls. The primary outcome was optimal post-PVR RV remodeling (end-diastolic volume index (EDVi) ≤ 114 ml/m2 and ejection fraction (EF) ≥ 48%) vs. suboptimal remodeling (EDVi ≥ 120 ml/m2 and EF ≤ 45%). RV geometry was markedly different at baseline in PVR patients compared with controls, with lower systolic surface area-to-volume ratio (SAVR) (1.16 ± 0.26 vs.1.44 ± 0.21 cm2/mL, p < 0.001) and lower systolic circumferential curvature (0.87 ± 0.27 vs. 1.07 ± 0.30 cm- 1, p = 0.007) but similar longitudinal curvature. In the PVR cohort, higher systolic SAVR was associated with higher RVEF both pre- and post-PVR (p < 0.001). Among PVR patients, 15 had optimal and 19 had suboptimal remodeling post-PVR. Multivariable modeling showed that among the geometric parameters, higher systolic SAVR (OR 1.68 per 0.1 cm2/mL increase; p = 0.049) and shorter systolic RV long-axis length (OR 0.92 per 0.1 cm increase; p = 0.035) were independently associated with optimal remodeling. Compared with controls, PVR patients have lower SAVR and lower circumferential but not longitudinal curvature. Higher pre-PVR systolic SAVR is associated with optimal remodeling post-PVR.

Left atrioventricular valve repair after primary atrioventricular canal surgery: Predictors of durability.

OBJECTIVE: Acute outcomes after atrioventricular canal defects (AVCD) surgery in the current era are excellent; yet despite surgical advances, ∼15% of patients require future left atrioventricular valve (LAVV) repair. Among patients with AVC who undergo LAVV repair after primary AVC surgery, we sought to characterize the durability of these repairs. Specifically, we aimed to determine predictors for reintervention following an LAVV repair in patients with repaired AVCD, with a focus on postoperative transesophageal echocardiography (TEE). METHODS: We reviewed all patients undergoing LAVV repair (after a primary AVCD surgery) at Boston Children's Hospital between 2010 and 2020. Competing risk analysis was performed to evaluate cumulative incidence of LAVV reinterventions. Predictors of LAVV reintervention were evaluated using multivariable Cox regression. RESULTS: A total of 137 LAVV repairs following primary AVCD surgery were performed in 113 patients. Median age and weight at LAVV repair were 25 months (interquartile range, 12-76 months) and 11.1 kg (interquartile range, 7.8-19.4 kg). Original anatomy was complete AVCD in 87 (63%), transitional AVCD in 27 (20%), and partial AVCD in 23 (17%) cases. Over a median follow-up of 12 months (interquartile range, 1.3 months-4 years), 47 (34%) of the LAVV repairs required LAVV reintervention. Reinterventions included a total of 27 LAVV re-repairs and 20 LAVV replacements. In multivariable analysis, age at LAVV repair younger than 72 months, partial AVCD anatomy, left ventricle dysfunction, mean LAVV stenosis gradient ≥5 mm Hg, and multiple jets of regurgitation on postoperative LAVV repair TEE were associated with LAVV reintervention. Grade of LAVV regurgitation on postoperative TEE was not an independent risk factor, but reintervention rates were high when residual LAVV stenosis gradient was ≥5 mm Hg and residual mild LAVV regurgitation was present on postoperative TEE (47%) and even higher when residual LAVV stenosis gradient was ≥5 mm Hg and LAVV regurgitation was greater than mild (73%). CONCLUSIONS: Reintervention rates remain high for LAVV repairs that occur after primary AVCD surgery, particularly for patients with LAVV stenosis gradient ≥5 mm Hg and mild or greater LAVV regurgitation on postoperative TEE.

Single Ventricle Reconstruction III: Brain Connectome and Neurodevelopmental Outcomes: Design, Recruitment, and Technical Challenges of a Multicenter, Observational Neuroimaging Study.

Patients with hypoplastic left heart syndrome who have been palliated with the Fontan procedure are at risk for adverse neurodevelopmental outcomes, lower quality of life, and reduced employability. We describe the methods (including quality assurance and quality control protocols) and challenges of a multi-center observational ancillary study, SVRIII (Single Ventricle Reconstruction Trial) Brain Connectome. Our original goal was to obtain advanced neuroimaging (Diffusion Tensor Imaging and Resting-BOLD) in 140 SVR III participants and 100 healthy controls for brain connectome analyses. Linear regression and mediation statistical methods will be used to analyze associations of brain connectome measures with neurocognitive measures and clinical risk factors. Initial recruitment challenges occurred related to difficulties with: 1) coordinating brain MRI for participants already undergoing extensive testing in the parent study, and 2) recruiting healthy control subjects. The COVID-19 pandemic negatively affected enrollment late in the study. Enrollment challenges were addressed by 1) adding additional study sites, 2) increasing the frequency of meetings with site coordinators and 3) developing additional healthy control recruitment strategies, including using research registries and advertising the study to community-based groups. Technical challenges that emerged early in the study were related to the acquisition, harmonization, and transfer of neuroimages. These hurdles were successfully overcome with protocol modifications and frequent site visits that involved human and synthetic phantoms. Trial registration number: ClinicalTrials.gov Registration Number: NCT02692443.

Single Ventricle Reconstruction III: Brain Connectome and Neurodevelopmental Outcomes: Design, Recruitment, and Technical Challenges of a Multicenter, Observational Neuroimaging Study.

Patients with hypoplastic left heart syndrome who have been palliated with the Fontan procedure are at risk for adverse neurodevelopmental outcomes, lower quality of life, and reduced employability. We describe the methods (including quality assurance and quality control protocols) and challenges of a multi-center observational ancillary study, SVRIII (Single Ventricle Reconstruction Trial) Brain Connectome. Our original goal was to obtain advanced neuroimaging (Diffusion Tensor Imaging and Resting-BOLD) in 140 SVR III participants and 100 healthy controls for brain connectome analyses. Linear regression and mediation statistical methods will be used to analyze associations of brain connectome measures with neurocognitive measures and clinical risk factors. Initial recruitment challenges occurred that were related to difficulties with: (1) coordinating brain MRI for participants already undergoing extensive testing in the parent study, and (2) recruiting healthy control subjects. The COVID-19 pandemic negatively affected enrollment late in the study. Enrollment challenges were addressed by: (1) adding additional study sites, (2) increasing the frequency of meetings with site coordinators, and (3) developing additional healthy control recruitment strategies, including using research registries and advertising the study to community-based groups. Technical challenges that emerged early in the study were related to the acquisition, harmonization, and transfer of neuroimages. These hurdles were successfully overcome with protocol modifications and frequent site visits that involved human and synthetic phantoms.

Normative Echocardiographic Left Ventricular Parameters and Reference Intervals in Infants.

BACKGROUND: In pediatric echocardiography, reference intervals are required to distinguish normal variation from pathology. Left ventricular (LV) parameters are particularly important predictors of clinical outcome. However, data from healthy newborns are limited, and current reference intervals provide an inadequate approximation of normal reference ranges. OBJECTIVES: Normative reference intervals and z-scores for 2-dimensional echocardiographic measurements of LV structure and function based on a large group of healthy newborns were developed. METHODS: The study population included 13,454 healthy newborns from the Copenhagen Baby Heart Study who were born at term to healthy mothers, had an echocardiogram performed within 30 days of birth, and did not have congenital heart disease. To develop normative reference intervals, this study modeled 10 LV parameters as a function of body surface area through joint modeling of 4 statistical components. RESULTS: Infants in the study population (48.5% were female) had a median body surface area of 0.23 m2 (IQR: 0.22-0.25 m2) and median age of 12.0 days (IQR: 8.0-15.0 days) at examination. All normative reference intervals performed well in both sexes without stratification on infant sex. In contrast, creation of separate reference models for infants examined at <7 days of age and those examined at 7-30 days of age was necessary to optimize the performance of the reference intervals. CONCLUSIONS: This study provides normative reference intervals and z-scores for 10 clinical, widely used echocardiographic measures of LV structure and function based on a large cohort of newborns. These results provide highly needed reference material for clinical application by pediatric cardiologists.

A comparison between the apical and subcostal view for three-dimensional echocardiographic assessment of right ventricular volumes in pediatric patients.

Background: Accurate measurement of ventricular volumes is an important clinical imaging goal. Three-dimensional echocardiography (3DEcho) is used increasingly as it is more available and less costly than cardiac magnetic resonance (CMR). For the right ventricle (RV), the current practice is to acquire 3DEcho volumes from the apical view. However, in some patients the RV may be better seen from the subcostal view. Therefore, this study compared RV volume measurements from the apical vs. the subcostal view, using CMR as a reference standard. Methods: Patients <18 years old undergoing a clinical CMR examination were prospectively enrolled. 3DEcho was performed on the day of the CMR. 3DEcho images were acquired with Philips Epic 7 ultrasound system from apical and subcostal views. Offline analysis was performed with TomTec 4DRV Function for 3DEcho images and cvi42 for CMR ones. RV end-diastolic volume and end-systolic volume were collected. Agreement between 3DEcho and CMR was assessed with Bland-Altman analysis and the intraclass correlation coefficient (ICC). Percentage (%) error was calculated using CMR as the reference standard. Results: Forty-seven patients were included in the analysis (age range 10 months to 16 years). The ICC was moderate to excellent for all volume comparisons to CMR (subcostal vs. CMR: end-diastolic volume 0.93, end-systolic volume 0.81; apical vs. CMR: end-diastolic volume 0.94, end-systolic volume 0.74).The 3DEcho mean % error vs. CMR for end-systolic volume was 25% for subcostal and 31% for apical; for end-diastolic volume it was 15% for subcostal and 16% for apical. The % error was not significantly different between apical vs. subcostal views for end-systolic and end-diastolic volume measurements. Conclusions: For apical and subcostal views, 3DEcho-derived ventricular volumes agree well with CMR. Neither echo view has a consistently smaller error when compared to CMR volumes. Accordingly, the subcostal view can be used as an alternative to the apical view when acquiring 3DEcho volumes in pediatric patients, particularly when the image quality from this window is superior.

Improved Outcomes After Pulmonary Valve Replacement in Repaired Tetralogy of Fallot.

BACKGROUND: The impact of pulmonary valve replacement (PVR) on major adverse clinical outcomes in patients with repaired tetralogy of Fallot (rTOF) is unknown. OBJECTIVES: The purpose of this study was to determine whether PVR is associated with improved survival and freedom from sustained ventricular tachycardia (VT) in rTOF. METHODS: A PVR propensity score was created to adjust for baseline differences between PVR and non-PVR patients enrolled in INDICATOR (International Multicenter TOF Registry). The primary outcome was time to the earliest occurrence of death or sustained VT. PVR and non-PVR patients were matched 1:1 on PVR propensity score (matched cohort) and in the full cohort, modeling was performed with propensity score as a covariate adjustment. RESULTS: Among 1,143 patients with rTOF (age 27 ± 14 years, 47% PVR, follow-up 8.3 ± 5.2 years), the primary outcome occurred in 82. The adjusted HR for the primary outcome for PVR vs no-PVR (matched cohort n = 524) was 0.41 (95% CI: 0.21-0.81; multivariable model P = 0.010). Full cohort analysis revealed similar results. Subgroup analysis suggested beneficial effects in patients with advanced right ventricular (RV) dilatation (interaction P = 0.046; full cohort). In patients with RV end-systolic volume index >80 mL/m2, PVR was associated with a lower primary outcome risk (HR: 0.32; 95% CI: 0.16-0.62; P < 0.001). There was no association between PVR and the primary outcome in patients with RV end-systolic volume index ≤80 mL/m2 (HR: 0.86; 95% CI: 0.38-1.92; P = 0.70). CONCLUSIONS: Compared with rTOF patients who did not receive PVR, propensity score-matched individuals receiving PVR had lower risk of a composite endpoint of death or sustained VT.

Factors associated with morbidity, mortality, and hemodynamic failure after biventricular conversion in borderline hypoplastic left hearts.

OBJECTIVE: A subset of patients with borderline hypoplastic left heart may be candidates for single to biventricular conversion, but long-term morbidity and mortality persist. Prior studies have shown conflicting results regarding the association of preoperative diastolic dysfunction and outcome, and patient selection remains challenging. METHODS: Patients with borderline hypoplastic left heart undergoing biventricular conversion from 2005 to 2017 were included. Cox regression identified preoperative factors associated with a composite outcome of time to mortality, heart transplant, takedown to single ventricle circulation, or hemodynamic failure (defined as left ventricular end-diastolic pressure >20 mm Hg, mean pulmonary artery pressure >35 mm Hg, or pulmonary vascular resistance >6 international Woods units). RESULTS: Among 43 patients, 20 (46%) met the outcome, with a median time to outcome of 5.2 years. On univariate analysis, endocardial fibroelastosis, lower left ventricular end-diastolic volume/body surface area (when <50 mL/m2), lower left ventricular stroke volume/body surface area (when <32 mL/m2), and lower left:right ventricular stroke volume ratio (when <0.7) were associated with outcome; higher preoperative left ventricular end-diastolic pressure was not. Multivariable analysis demonstrated that endocardial fibroelastosis (hazard ratio, 5.1, 95% confidence interval, 1.5-22.7, P = .033) and left ventricular stroke volume/body surface area 28 mL/m2 or less (hazard ratio, 4.3, 95% confidence interval, 1.5-12.3, P = .006) were independently associated with a higher hazard of the outcome. Approximately all patients (86%) with endocardial fibroelastosis and left ventricular stroke volume/body surface area 28 mL/m2 or less met the outcome compared with 10% of those without endocardial fibroelastosis and with higher stroke volume/body surface area. CONCLUSIONS: History of endocardial fibroelastosis and smaller left ventricular stroke volume/body surface area are independent factors associated with adverse outcomes among patients with borderline hypoplastic left heart undergoing biventricular conversion. Normal preoperative left ventricular end-diastolic pressure is insufficient to reassure against diastolic dysfunction after biventricular conversion.

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

BACKGROUND: Currently there are no immunosuppression regimens FDA-approved to prevent rejection in pediatric heart transplantation (HT). In recent years, everolimus (EVL) has emerged as a potential alternative to standard tacrolimus (TAC) as the primary immunosuppressant to prevent rejection that may also reduce the risk of cardiac allograft vasculopathy (CAV), chronic kidney disease (CKD) and cytomegalovirus (CMV) infection. However, the 2 regimens have never been compared head-to-head in a randomized trial. The study design and rationale are reviewed in light of the challenges inherent in rare disease research. METHODS: The TEAMMATE trial (IND 127980) is the first multicenter randomized clinical trial (RCT) in pediatric HT. The primary purpose is to evaluate the safety and efficacy of EVL and low-dose TAC (LD-TAC) compared to standard-dose TAC and mycophenolate mofetil (MMF). Children aged <21 years at HT were randomized (1:1 ratio) at 6 months post-HT to either regimen, and followed for 30 months. Children with recurrent rejection, multi-organ transplant recipients, and those with an estimated glomerular filtration rate (eGFR) <30 mL/min/1.73m2 were excluded. The primary efficacy hypothesis is that, compared to TAC/MMF, EVL/LD-TAC is more effective in preventing 3 MATEs: acute cellular rejection (ACR), CKD and CAV. The primary safety hypothesis is that EVL/LD-TAC does not have a higher cumulative burden of 6 MATEs (antibody mediated rejection [AMR], infection, and post-transplant lymphoproliferative disorder [PTLD] in addition to the 3 above). The primary endpoint is the MATE score, a composite, ordinal surrogate endpoint reflecting the frequency and severity of MATEs that is validated against graft loss. The study had a target sample size of 210 patients across 25 sites and is powered to demonstrate superior efficacy of EVL/LD-TAC. Trial enrollment is complete and participant follow-up will be completed in 2023. CONCLUSION: The TEAMMATE trial is the first multicenter RCT in pediatric HT. It is anticipated that the study will provide important information about the safety and efficacy of everolimus vs tacrolimus-based regimens and will provide valuable lessons into the design and conduct of future trials in pediatric HT.