Chronic Hypoxia in an EXTrauterine Environment for Neonatal Development Impairs Lung Development.

Severe fetal hypoxia poses a significant risk to lung development resulting in severe postnatal complications. Existing chronic hypoxia animal models lack the ability to achieve pathologically reduced fetal oxygen without compromising animal development, placental blood flow, or maternal health. Using an established model of isolated chronic hypoxia involving the Extrauterine Environment for Neonatal Development (EXTEND), we are able to investigate the direct impact of fetal hypoxia on lung development. Oxygen delivery to preterm fetal lambs (105-110 days GA) delivered by cesarean section was reduced, and animals were supported on EXTEND through the canalicular or saccular stage of lung development. Fetal lambs in hypoxic conditions showed significant growth restriction compared to their normoxic counterparts. We also observed modest aberrant vascular remodeling in the saccular group after hypoxic conditions with decreased macrovessel numbers, microvascular endothelial cell numbers, and increased peripheral vessel muscularization. In addition, fetal hypoxia resulted in enlarged distal airspaces and decreased septal wall volume. Moreover, there was a reduction in mature SFTPB and processed SFTPC protein expression concomitant with a decrease in AT2 cell number. These findings demonstrate that maternally-independent fetal hypoxia predominantly impacts distal airway development, AT2 cell number, and surfactant production with mild effects on the vasculature.

Diagnostic Yield of Exome Sequencing in Pediatric Cardiomyopathy.

OBJECTIVE: To assess the diagnostic yield of exome sequencing (ES) in pediatric cardiomyopathy. STUDY DESIGN: A single-institution, retrospective chart review of 91 patients with pediatric cardiomyopathy was performed. While pediatric cardiomyopathy is often genetic in nature, no genetic test is recommended as standard of care. All our patients were diagnosed with cardiomyopathy and evaluated by a medical geneticist between January 2010 through September 2022. Demographic information and clinical data were abstracted. RESULTS: Of 91 patients with pediatric cardiomyopathy, 36 (39.6%) received a diagnosis by ES. Twenty-two (61.1%) of these diagnoses would have been missed on cardiac multigene panel testing. The diagnostic yield for cardiomyopathy presenting under 1 year of age was 38.3%, while the yield for patients over 1 year of age was 41.9%. CONCLUSIONS: ES has a high diagnostic yield in pediatric cardiomyopathy compared with a gene panel. Over 60% of patients with diagnosis by ES would not have received their molecular genetic diagnosis if only multigene panel testing was sent. Diagnostic yield did not vary significantly between the subtypes of cardiomyopathy and patient age groups, highlighting the likely clinical utility of ES for all pediatric cardiomyopathy patients.

Patent ductus arteriosus and coarctation of the aorta in association with PRDM6 variants.

Patent ductus arteriosus (PDA) and coarctation of the aorta (CoA) are relatively common congenital heart defects. Pathogenic variants in PRDM6, which encodes a smooth-muscle-cell-specific transcription factor, have now been etiologically associated with non-syndromic PDA. We present three patients with PDA and CoA found to harbor PRDM6 variants, including a novel, likely-pathogenic variant.

Unique model of chronic hypoxia in fetal lambs demonstrates abnormal contrast-enhanced ultrasound brain perfusion.

BACKGROUND: Children with congenital heart disease (CHD) demonstrate long-term neurodevelopmental impairments. We investigated contrast-enhanced ultrasound (CEUS) cerebral perfusion in a fetal animal model exposed to sub-physiologic oxygen at equivalent levels observed in human fetuses with CHD. METHODS: Fifteen fetal lambs [hypoxic animals (n = 9) and normoxic controls (n = 6)] maintained in an extrauterine environment underwent periodic brain CEUS. Perfusion parameters including microvascular flow velocity (MFV), transit time, and microvascular blood flow (MBF) were extrapolated from a standardized plane; regions of interest (ROI) included whole brain, central/thalami, and peripheral parenchymal analyses. Daily echocardiographic parameters and middle cerebral artery (MCA) pulsatility indices (PIs) were obtained. RESULTS: Hypoxic lambs demonstrated decreased MFV, increased transit time, and decreased MBF (p = 0.026, p = 0.016, and p < 0.001, respectively) by whole brain analyses. MFV and transit time were relatively preserved in the central/thalami (p = 0.11, p = 0.08, p = 0.012, respectively) with differences in the peripheral parenchyma (all p < 0.001). In general, cardiac variables did not correlate with cerebral CEUS perfusion parameters. Hypoxic animals demonstrated decreased MCA PI compared to controls (0.65 vs. 0.78, respectively; p = 0.027). CONCLUSION: Aberrations in CEUS perfusion parameters suggest that in environments of prolonged hypoxia, there are regional microvascular differences incompletely characterized by MCA interrogation offering insights into fetal conditions which may contribute to patient outcomes. IMPACT: This work utilizes CEUS to study cerebral microvascular perfusion in a unique fetal animal model subjected to chronic hypoxic conditions equal to fetuses with congenital heart disease. CEUS demonstrates altered parameters with regional differences that are incompletely characterized by MCA Doppler values. These findings show that routine MCA Doppler interrogation may be inadequate in assessing microvascular perfusion differences. To our knowledge, this study is the first to utilize CEUS to assess microvascular perfusion in this model. The results offer insight into underlying conditions and physiological changes which may contribute to known neurodevelopmental impairments in those with congenital heart disease.

A case-control study of bleeding risk in children with 22q11.2 deletion syndrome undergoing cardiac surgery.

Previous research suggests that individuals with 22q11.2 deletion syndrome (DS) have an increased risk of bleeding following cardiac surgery. However, current guidelines for management of patients with 22q11.2DS do not provide specific recommendations for perioperative management. This study sought to identify specific risk factors for bleeding in this patient population. Examine the factors determining bleeding and transfusion requirements in patients with 22q11.2DS undergoing cardiac surgery. This was a single center review of patients who underwent cardiac surgery at the Children's Hospital of Philadelphia from 2000 to 2016. Data was extracted from the medical record. Frequency of bleeding events, laboratory values, and transfusion requirements were compared. We included 226 patients with 22q11.2DS and 506 controls. Bleeding events were identified in 13 patients with 22q11.2DS (5.8%) and 27 controls (5.3%). Platelet counts were lower among patients with 22q11.2DS than in control patients, but not statistically different comparing bleeding to not bleeding. Patients with 22q11.2DS received more transfusions (regardless of bleeding status). However, multivariate analysis showed only procedure type was associated with increased risk of bleeding (p = .012). The overall risk of bleeding when undergoing cardiac surgery is not different in patients with 22q11.2DS compared to non-deleted patients. Though platelet counts were lower in patients with 22q11.2DS, only procedure type was significantly associated with an increased risk of bleeding.

Hospital variation in post-operative cardiac extracorporeal membrane oxygenation use and relationship to post-operative mortality.

OBJECTIVE: It is unclear how extracorporeal membrane oxygenation use varies across paediatric cardiac surgical programmes and how it relates to post-operative mortality. We aimed to determine hospital-level variation in post-operative extracorporeal membrane oxygenation use and its association with case-mix adjusted mortality. METHODS: Retrospective analysis of 37 hospitals contributing to the Pediatric Cardiac Critical Care Consortium clinical registry from 1 August 2014 to 31 December 2019. Hospitalisations including cardiothoracic surgery and post-operative admission to paediatric cardiac ICUs were included. Two-level multivariable logistic regression with hospital random effect was used to determine case-mix adjusted post-operative extracorporeal membrane oxygenation use rates and in-hospital mortality. Hospitals were grouped into extracorporeal membrane oxygenation use tertiles, and mortality was compared across tertiles. RESULTS: There were 43,640 eligible surgical hospitalisations; 1397 (3.2%) included at least one post-operative extracorporeal membrane oxygenation run. Case-mix adjusted extracorporeal membrane oxygenation rates varied more than sevenfold (0.9-6.9%) across hospitals, and adjusted mortality varied 10-fold (0-5.5%). Extracorporeal membrane oxygenation rates were 2.0%, 3.5%, and 5.2%, respectively, for low, middle, and high extracorporeal membrane oxygenation use tertiles (P < 0.0001), and mortality rates were 1.9%, 3.0%, and 3.1% (p < 0.0001), respectively. High extracorporeal membrane oxygenation use hospitals were more likely to initiate extracorporeal membrane oxygenation support intraoperatively (1.6% vs. 0.6% low and 1.1% middle, p < 0.0001). Extracorporeal membrane oxygenation indications were similar across hospital tertiles. When extracorporeal cardiopulmonary resuscitation was excluded, variation in extracorporeal membrane oxygenation use rates persisted (1.5%, 2.6%, 3.8%, p < 0.001). CONCLUSIONS: There is hospital variation in adjusted post-operative extracorporeal membrane oxygenation use after paediatric cardiac surgery and a significant association with adjusted post-operative mortality. These findings suggest that post-operative extracorporeal membrane oxygenation use could be a complementary quality metric to mortality to assess performance of cardiac surgical programmes.

Lung volumes are increased in fetuses with transposition of the great arteries on intrauterine MRI.

Fetal brain size is decreased in some children with complex CHDs, and the distribution of blood and accompanying oxygen and nutrients is regionally skewed from early fetal life dependent on the CHD. In transposition of the great arteries, deoxygenated blood preferentially runs to the brain, whereas the more oxygenated blood is directed towards the lungs and the abdomen. Knowledge of whether this impacts intrauterine organ development is limited. We investigated lung, liver, and total intracranial volume in fetuses with transposition of the great arteries using MRI.Eight fetuses with dextro-transposition and without concomitant disease or chromosomal abnormalities and 42 fetuses without CHD or other known diseases were scanned once or twice at gestational age 30 through 39 weeks. The MRI scans were conducted on a 1.5T system, using a 2D balanced steady-state free precession sequence. Slices acquired covered the entire fetus, slice thickness was 10 mm, pixel size 1.5 × 1.5 mm, and scan duration was 30 sec.The mean lung z score was significantly larger in fetuses with transposition compared with those without a CHD; mean difference is 1.24, 95% CI:(0.59;1.89), p < 0.001. The lung size, corrected for estimated fetal weight, was larger than in the fetuses without transposition; mean difference is 8.1 cm3/kg, 95% CI:(2.5;13.7 cm3/kg), p = 0.004.In summary, fetuses with dextro-transposition of the great arteries had both absolute and relatively larger lung volumes than those without CHD. No differences were seen in liver and total intracranial volume. Despite the small number of cases, the results are interesting and warrant further investigation.

Conjugated hyperbilirubinemia is associated with increased morbidity and mortality after neonatal heart surgery.

BACKGROUND: Cholestasis characterised by conjugated hyperbilirubinemia is a marker of hepatobiliary dysfunction following neonatal cardiac surgery. We aimed to characterise the incidence of conjugated hyperbilirubinemia following neonatal heart surgery and examine the effect of conjugated hyperbilirubinemia on post-operative morbidity and mortality. METHODS: This was a retrospective study of all neonates who underwent surgery for congenital heart disease (CHD) at our institution between 1/1/2010 and 12/31/2020. Patient- and surgery-specific data were abstracted from local registry data and review of the medical record. Conjugated hyperbilirubinemia was defined as perioperative maximum conjugated bilirubin level > 1 mg/dL. The primary outcome was in-hospital mortality. Survival analysis was conducted using the Kaplan-Meier survival function. RESULTS: Conjugated hyperbilirubinemia occurred in 8.5% of patients during the study period. Neonates with conjugated hyperbilirubinemia were more likely to be of younger gestational age, lower birth weight, and non-Caucasian race (all p < 0.001). Patients with conjugated hyperbilirubinemia were more likely to have chromosomal and non-cardiac anomalies and require ECMO pre-operatively. In-hospital mortality among patients with conjugated hyperbilirubinemia was increased compared to those without (odds ratio 5.4). Post-operative complications including mechanical circulatory support, reoperation, prolonged ventilator dependence, and multi-system organ failure were more common with conjugated hyperbilirubinemia (all p < 0.04). Patients with higher levels of conjugated bilirubin had worst intermediate-term survival, with patients in the highest conjugated bilirubin group (>10 mg/dL) having a 1-year survival of only 6%. CONCLUSIONS: Conjugated hyperbilirubinemia is associated with post-operative complications and worse survival following neonatal heart surgery. Cholestasis is more common in patients with chromosomal abnormalities and non-cardiac anomalies, but the underlying mechanisms have not been delineated.

Development of the data registry for the Cardiac Neurodevelopmental Outcome Collaborative.

Children with congenital heart disease (CHD) can face neurodevelopmental, psychological, and behavioural difficulties beginning in infancy and continuing through adulthood. Despite overall improvements in medical care and a growing focus on neurodevelopmental screening and evaluation in recent years, neurodevelopmental disabilities, delays, and deficits remain a concern. The Cardiac Neurodevelopmental Outcome Collaborative was founded in 2016 with the goal of improving neurodevelopmental outcomes for individuals with CHD and pediatric heart disease. This paper describes the establishment of a centralised clinical data registry to standardize data collection across member institutions of the Cardiac Neurodevelopmental Outcome Collaborative. The goal of this registry is to foster collaboration for large, multi-centre research and quality improvement initiatives that will benefit individuals and families with CHD and improve their quality of life. We describe the components of the registry, initial research projects proposed using data from the registry, and lessons learned in the development of the registry.

Normoxic Management during Cardiopulmonary Bypass Does Not Reduce Cerebral Mitochondrial Dysfunction in Neonatal Swine.

Optimal oxygen management during pediatric cardiopulmonary bypass (CPB) is unknown. We previously demonstrated an increase in cortical mitochondrial reactive oxygen species and decreased mitochondrial function after CPB using hyperoxic oxygen management. This study investigates whether controlled oxygenation (normoxia) during CPB reduces cortical mitochondrial dysfunction and oxidative injury. Ten neonatal swine underwent three hours of continuous CPB at 34 °C (flow > 100 mL/kg/min) via cervical cannulation targeting a partial pressure of arterial oxygen (PaO2) goal < 150 mmHg (normoxia, n = 5) or >300 mmHg (hyperoxia, n = 5). The animals underwent continuous hemodynamic monitoring and serial arterial blood sampling. Cortical microdialysate was serially sampled to quantify the glycerol concentration (represents neuronal injury) and lactate-to-pyruvate ratio (represents bioenergetic dysfunction). The cortical tissue was analyzed via high-resolution respirometry to quantify mitochondrial oxygen consumption and reactive oxygen species generation, and cortical oxidized protein carbonyl concentrations were quantified to assess for oxidative damage. Serum PaO2 was higher in hyperoxia animals throughout CPB (p < 0.001). There were no differences in cortical glycerol concentration between groups (p > 0.2). The cortical lactate-to-pyruvate ratio was modestly elevated in hyperoxia animals (p < 0.03) but the values were not clinically significant (<30). There were no differences in cortical mitochondrial respiration (p = 0.48), protein carbonyls (p = 0.74), or reactive oxygen species generation (p = 0.93) between groups. Controlled oxygenation during CPB does not significantly affect cortical mitochondrial function or oxidative injury in the acute setting. Further evaluation of the short and long-term effects of oxygen level titration during pediatric CPB on cortical tissue and other at-risk brain regions are needed, especially in the presence of cyanosis.

A fetal wound healing program after intrauterine bile duct injury may contribute to biliary atresia.

BACKGROUND & AIMS: Biliary atresia (BA) is an obstructive cholangiopathy that initially affects the extrahepatic bile ducts (EHBDs) of neonates. The etiology is uncertain, but evidence points to a prenatal cause. Fetal tissues have increased levels of hyaluronic acid (HA), which plays an integral role in fetal wound healing. The objective of this study was to determine whether a program of fetal wound healing is part of the response to fetal EHBD injury. METHODS: Mouse, rat, sheep, and human EHBD samples were studied at different developmental time points. Models included a fetal sheep model of prenatal hypoxia, human BA EHBD remnants and liver samples taken at the time of the Kasai procedure, EHBDs isolated from neonatal rats and mice, and spheroids and other models generated from primary neonatal mouse cholangiocytes. RESULTS: A wide layer of high molecular weight HA encircling the lumen was characteristic of the normal perinatal but not adult EHBD. This layer, which was surrounded by collagen, expanded in injured ducts in parallel with extensive peribiliary gland hyperplasia, increased mucus production and elevated serum bilirubin levels. BA EHBD remnants similarly showed increased HA centered around ductular structures compared with age-appropriate controls. High molecular weight HA typical of the fetal/neonatal ducts caused increased cholangiocyte spheroid growth, whereas low molecular weight HA induced abnormal epithelial morphology; low molecular weight HA caused matrix swelling in a bile duct-on-a-chip device. CONCLUSION: The fetal/neonatal EHBD, including in human EHBD remnants from Kasai surgeries, demonstrated an injury response with prolonged high levels of HA typical of fetal wound healing. The expanded peri-luminal HA layer may swell and lead to elevated bilirubin levels and obstruction of the EHBD. IMPACT AND IMPLICATIONS: Biliary atresia is a pediatric cholangiopathy associated with high morbidity and mortality rates; although multiple etiologies have been proposed, the fetal response to bile duct damage is largely unknown. This study explores the fetal pathogenesis after extrahepatic bile duct damage, thereby opening a completely new avenue to study therapeutic targets in the context of biliary atresia.

Differences in Quality of Life in Children Across the Spectrum of Congenital Heart Disease.

OBJECTIVE: To create complexity groups based upon a patient's cardiac medical history and to test for group differences in health-related quality of life (HRQOL). METHODS: Patients 8-18 years with congenital heart disease (CHD) and parent-proxies from the Pediatric Cardiac Quality of Life Inventory (PCQLI) Testing Study were included. Outcome variables included PCQLI Total, Disease Impact, and Psychosocial Impact scores. Using a patient's medical history (cardiac, neurologic, psychological, and cognitive diagnosis), latent class analysis (LCA) was used to create CHD complexity groups. Covariates included demographics and burden of illness (number of: school weeks missed, physician visits in the past year, and daily medications). Generalized estimation equations tested for differences in burden of illness and patient and parent-proxy PCQLI scores. RESULTS: Using 1482 CHD patients (60% male; 84% white; age 12.3 ± 3.0 years), latent class analysis (LCA) estimates showed 4 distinct CHD complexity groups (Mild, Moderate 1, Moderate 2, and Severe). Increasing CHD complexity was associated with increased risk of learning disorders, seizures, mental health problems, and history of stroke. Greater CHD complexity was associated with greater burden of illness (P < .01) and lower patient- and parent-reported PCQLI scores (P < .001). CONCLUSIONS: LCA identified 4 congenital heart disease (CHD) complexity groupings. Increasing CHD complexity was associated with higher burden of illness and worse patient- and parent-reported HRQOL.

Anesthesia and Sedation Exposure and Neurodevelopmental Outcomes in Infants Undergoing Congenital Cardiac Surgery: A Retrospective Cohort Study.

BACKGROUND: Children undergoing complex cardiac surgery are exposed to substantial cumulative doses of sedative medications and volatile anesthetics and are more frequently anesthetized with ketamine, compared with healthy children. This study hypothesized that greater exposure to sedation and anesthesia in this population is associated with lower neurodevelopmental scores at 18 months of age. METHODS: A secondary analysis was conducted of infants with congenital heart disease who participated in a prospective observational study of environmental exposures and neurodevelopmental outcomes to assess the impact of cumulative volatile anesthetic agents and sedative medications. Cumulative minimum alveolar concentration hours of exposure to volatile anesthetic agents and all operating room and intensive care unit exposures to sedative and anesthesia medications were collected before administration of Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley III), at 18 months of age. RESULTS: The study cohort included 41 (37%) single-ventricle and 69 (63%) two-ventricle patients. Exposures to volatile anesthetic agents, opioids, benzodiazepines, and dexmedetomidine were not associated with abnormal Bayley III scores. At 18-month follow-up, after adjusting for confounders, each mg/kg increase in ketamine exposure was associated with a 0.34 (95% CI, -0.64 to -0.05) point decrease in Bayley III motor scores (P = 0.024). CONCLUSIONS: Total cumulative exposures to volatile anesthetic agents were not associated with neurodevelopmental impairment in infants with congenital heart disease undergoing various imaging studies and procedures, whereas higher ketamine doses were associated with poorer motor performance.

Reduced incidence of cardiac rejection in multi-organ transplants: A propensity matched study.

BACKGROUND: Rejection remains a primary cause of graft loss after heart transplant (HT). Recognizing the immunomodulation of multi-organ transplant can enhance our understanding of the mechanisms of cardiac rejection. METHODS: This retrospective cohort study identified patients from the UNOS database with isolated heart (H, N = 37 433), heart-kidney (HKi, N = 1516), heart-liver (HLi, N = 286), and heart-lung (HLu, N = 408) transplants from 2004 to 2019. Propensity score matching reduced baseline differences between groups. Outcomes included risk of rejection prior to transplant hospital discharge and within 1 year, and mortality within 1 year of transplant. RESULTS: In the propensity score matched data, the relative risk of being treated for rejection prior to transplant hospital discharge was 61% lower for HKi (RR .39, 95% CI .29, .53) and 87% lower for HLi (RR .13, 95% CI .05, .37) compared to H. Similarly, the probability of being treated for rejection in the first year after transplant remained lower in HKi (RR .45, 95% CI .35, .57) and HLi (RR .13, 95% CI .06, .28) compared to H. The 1-year survival analysis revealed an equivalent risk of death in HKi (HR .84, 95% CI .68, 1.03) and HLi (HR 1.41, 95% CI .83, 2.41) compared to H, while HLu had a higher risk of death in the first year after transplant (HR 1.65, 95% CI 1.17, 2.33). CONCLUSIONS: Recipients of HKi and HLi experience a reduced risk of rejection when compared to H, but an equivalent risk of 1 yr mortality. These findings have important implications for the future of HT medicine.

Long-Term Quality of Life in Congenital Heart Disease Surgical Survivors: Multicenter Retrospective Study of Surgical and ICU Explanatory Factors.

OBJECTIVES: Greater congenital heart disease (CHD) complexity is associated with lower health-related quality of life (HRQOL). There are no data on the association between surgical and ICU factors and HRQOL in CHD survivors. This study assess the association between surgical and ICU factors and HRQOL in child and adolescent CHD survivors. DESIGN: This was a corollary study of the Pediatric Cardiac Quality of Life Inventory (PCQLI) Testing Study. SETTING: Eight pediatric hospitals participating in the PCQLI Study. PATIENTS: Patients in the study had the Fontan procedure, surgery for tetralogy of Fallot (TOF), and transposition of the great arteries (TGAs). MEASUREMENTS AND MAIN RESULTS: Surgical/ICU explanatory variables were collected by reviewing the medical records. Primary outcome variables (PCQLI Total patient and parent scores) and covariates were obtained from the Data Registry. General linear modeling was used to create the multivariable models. There were 572 patients included: mean ± sd of age 11.7 ± 2.9 years; CHD Fontan 45%, TOF/TGA 55%; number of cardiac surgeries 2 (1-9); and number of ICU admissions 3 (1-9). In multivariable models, lowest body temperature on cardiopulmonary bypass (CPB) was negatively associated with patient total score (p < 0.05). The total number of CPB runs was negatively associated with parent-reported PCQLI Total score (p < 0.02). Cumulative days on an inotropic/vasoactive drug in the ICU was negatively associated with all patient-/parent-reported PCQLI scores (p < 0.04). Neurological deficit at discharge was negatively associated with parent-reported PCQLI total score (p < 0.02). The variance explained by these factors ranged from 24% to 29%. CONCLUSIONS: Surgical/ICU factors, demographic, and medical care utilization variables explain a low-to-moderate amount of variation in HRQOL. Research is needed to determine whether modification of these surgical and ICU factors improves HRQOL, and to identify other factors that contribute to unexplained variability.

Noonan syndrome associated with hypoplastic left heart syndrome.

Noonan syndrome is an inherited disorder caused by alterations in the RAS-MAPK pathway. There have been several identified genotype-phenotype associations made with respect to congenital cardiac lesions and Noonan syndrome variants, but limited data exist regarding single ventricle disease in this population. Here, we report two patients with PTPN11-related Noonan syndrome and hypoplastic left heart syndrome variants.

Radiographic and histologic characterisation of white matter injury in a sheep model of CHD.

Nearly one in five children with CHD is born with white matter injury that can be recognised on postnatal MRI by the presence of T1 hyperintense lesions. This pattern of white matter injury is known to portend poor neurodevelopmental outcomes, but the exact aetiology and histologic characterisation of these lesions have never been described. A fetal sheep was cannulated at gestational age 110 days onto a pumpless extracorporeal oxygenator via the umbilical vessels and supported in a fluid environment for 14.5 days. The fetus was supported under hypoxic conditions (mean oxygen delivery 16 ml/kg/day) to simulate the in utero conditions of CHD. At necropsy, the brain was fixed, imaged with MRI, and then stained to histologically identify areas of injury. Under hypoxemic in utero conditions, the fetus developed a T1 hyperintense lesion in its right frontal lobe. Histologically, this lesion was characterised by microvascular proliferation and astrocytosis without gliosis. These findings may provide valuable insight into the aetiology of white matter injury in neonates with CHD.

Hereditary haemorrhagic telangiectasia and SMAD4 mutation in a patient with complex single ventricle heart disease.

We report a case of hypoplastic left heart syndrome and with subsequent aortopathy and then found to have hereditary haemorrhagic telangiectasia/juvenile polyposis syndrome due to a germline SMAD4 pathologic variant. The patient's staged palliation was complicated by the development of neoaortic aneurysms, arteriovenous malformations, and gastrointestinal bleeding thought to be secondary to Fontan circulation, but workup revealed a SMAD4 variant consistent with hereditary haemorrhagic telangiectasia/juvenile polyposis syndrome. This case underscores the importance of genetic modifiers in CHD, especially those with Fontan physiology.

Neurologic complications of infective endocarditis in children.

OBJECTIVES: To define the frequency and characteristics of acute neurologic complications in children hospitalised with infective endocarditis and to identify risk factors for neurologic complications. STUDY DESIGN: Retrospective cohort study of children aged 0-18 years hospitalised at a tertiary children's hospital from 1 January, 2008 to 31 December, 2017 with infective endocarditis. RESULTS: Sixty-eight children met Duke criteria for infective endocarditis (43 definite and 25 possible). Twenty-three (34%) had identified neurologic complications, including intracranial haemorrhage (25%, 17/68) and ischaemic stroke (25%, 17/68). Neurologic symptoms began a median of 4.5 days after infective endocarditis symptom onset (interquartile range 1, 25 days), though five children were asymptomatic and diagnosed on screening neuroimaging only. Overall, only 56% (38/68) underwent neuroimaging during acute hospitalisation, so additional asymptomatic neurologic complications may have been missed. Children with identified neurologic complications compared to those without were older (48 versus 22% ≥ 13 years old, p = 0.031), more often had definite rather than possible infective endocarditis (96 versus 47%, p < 0.001), mobile vegetations >10mm (30 versus 11%, p = 0.048), and vegetations with the potential for systemic embolisation (65 versus 29%, p = 0.004). Six children died (9%), all of whom had neurologic complications. CONCLUSIONS: Neurologic complications of infective endocarditis were common (34%) and associated with mortality. The true frequency of neurologic complications was likely higher because asymptomatic cases may have been missed without screening neuroimaging. Moving forward, we advocate that all children with infective endocarditis have neurologic consultation, examination, and screening neuroimaging. Additional prospective studies are needed to determine whether early identification of neurologic abnormalities may direct management and ultimately reduce neurologic morbidity and overall mortality.

The pediatric heart network's study on long-term outcomes of children with HLHS and the impact of Norwood Shunt type in the single ventricle reconstruction trial cohort (SVRIII): Design and adaptations.

BACKGROUND: The Single Ventricle Reconstruction (SVR) Trial was the first randomized clinical trial of a surgical approach for treatment of congenital heart disease. Infants with hypoplastic left heart syndrome (HLHS) and other single right ventricle (RV) anomalies were randomized to a modified Blalock Taussig Thomas shunt (mBTTS) or a right-ventricular-to-pulmonary-artery shunt (RVPAS) at the time of the Norwood procedure. The aim of the Long-term Outcomes of Children with HLHS and the Impact of Norwood Shunt Type (SVR III) study is to compare early adolescent outcomes including measures of cardiac function, transplant-free survival, and neurodevelopment, between those who received a mBTTS and those who received an RVPAS. METHODS: Transplant-free survivors of the SVR cohort were enrolled at 10 to 15 years of age for multifaceted in-person evaluation of cardiac function (cardiac magnetic resonance [CMR], echocardiogram and exercise test) and neurodevelopmental evaluation. Right ventricular ejection fraction measured by CMR served as the primary outcome. Development of arrhythmias, protein losing enteropathy, and other comorbidities were assessed through annual medical history interview. Through the course of SVR III, protocol modifications to engage SVR trial participants were designed to enhance recruitment and retention. CONCLUSIONS: Evaluation of long-term outcomes will provide important data to inform decisions about the shunt type placed at the Norwood operation and will improve the understanding of cardiovascular and neurodevelopmental outcomes for early adolescents with HLHS.