Cortical Dysmaturation in Congenital Heart Disease

A case report of spastic diplegic cerebral palsy in a late preterm child with hypoplastic left heart syndrome

Background

Congenital heart disease (CHD) is the most common birth defect, affecting 1% of children who are born in the United States each year. Children with hypoplastic left heart syndrome, a type of critical CHD, are at high risk for neurodevelopmental disabilities, which are conditions that can affect motor, language, and cognitive development. In children with critical CHD, the severity and prevalence of their motor delays is most pronounced in infancy.

Case Description

We present a case of a former late preterm male with hypoplastic left heart syndrome and history of hypoxic ischemic encephalopathy, who was diagnosed with spastic diplegic cerebral palsy in the setting of periventricular leukomalacia. Like many children with critical CHD, this child had gross motor delays and tone abnormalities in infancy. However, unlike many children with CHD, he continued to have neurologic differences that prompted additional evaluation through a Cardiac Neurodevelopmental Program. He was diagnosed with spastic diplegic cerebral palsy based upon clinical history and physical examination. Ancillary testing showed periventricular leukomalacia on brain magnetic resonance imaging (MRI); this finding was consistent with his clinical diagnosis.

Conclusions

This is an interesting case report of spastic diplegic cerebral palsy in a late preterm infant with critical CHD. When making a diagnosis of cerebral palsy, it is important to consider the etiology of the motor impairment. Selective vulnerability may have played a factor in this child's condition. The most vulnerable part of the neonatal brain is the periventricular white matter; cerebral hypoxia can lead to periventricular leukomalacia. Children with CHD have brain dysmaturity beginning in-utero. Thus, it is possible that this child's brain dysmaturity may have increased his susceptibility to periventricular leukomalacia. Because most children with CHD have gross motor delays in infancy, it may be challenging to make a definitive diagnosis of cerebral palsy in an infant with critical CHD. Children with cerebral palsy have early motor delays that persist throughout life. It is the identification of persistent motor impairments through repeat evaluations that enabled this child's cerebral palsy diagnosis. This illustrates the importance of developmental surveillance in children with critical CHD.

Neurological injury in pediatric heart disease: A review of developmental and acquired risk factors and management considerations

Medical and surgical advancements have improved survival in children with acquired and congenital heart disease (CHD), but the burden of neurological morbidity is high. Brain disorders associated with CHD include white matter injury, stroke, seizure, and neurodevelopmental delays. While genetics and disease-specific factors play a substantial role in early brain injury, therapeutic management of the heart disease intensifies the risk. There is a growing interest in understanding how to reduce brain injury and improve neurodevelopmental outcomes in cardiac diseases. Pediatric neurologists serve a vital role in care teams managing these complex patients, providing interpretation of neuromonitoring and imaging, managing neurologic emergencies, assisting with neuro prognostication, and identifying future research aims.

Patterns of WISC-V Performance in Children with Congenital Heart Disease

Congenital heart disease (CHD) is one of the most common congenital birth defects. As surgical and interventional techniques have improved, the mortality has been greatly reduced and the focus has shifted to quality of life and long-term outcomes. The impact of CHD on development and cognition is becoming increasingly recognized. However, more research is needed to understand how children with CHD perform across various cognitive and intellectual domains. This study explored the performance of children with CHD on the newest version of the Wechsler Intelligence Scale for Children compared to normative controls. Children with CHD performed more poorly than normal controls across all indices and most subtests with large effect sizes. Additionally, we explored the patterns of impairment across indices and subtests, as well as the relationships between heard disease variables and WISC-V performance. Block design, Digit Span, and Similarities were the most commonly impaired scores in children with CHD, while Symbol Search, Picture Span, Figure Weights, and Vocabulary were least likely to be impaired.

[Formula: see text] Trajectories of neurodevelopment and opportunities for intervention across the lifespan in congenital heart disease

Children with congenital heart disease (CHD) are at increased risk for neurodevelopmental challenges across the lifespan. These are associated with neurological changes and potential acquired brain injury, which occur across a developmental trajectory and which are influenced by an array of medical, sociodemographic, environmental, and personal factors. These alterations to brain development lead to an array of adverse neurodevelopmental outcomes, which impact a characteristic set of skills over the course of development. The current paper reviews existing knowledge of aberrant brain development and brain injury alongside associated neurodevelopmental challenges across the lifespan. These provide a framework for discussion of emerging and potential interventions to improve neurodevelopmental outcomes at each developmental stage.

Cerebral Spinal Fluid Volumetrics and Paralimbic Predictors of Executive Dysfunction in Congenital Heart Disease: A Machine Learning Approach Informing Mechanistic Insights

The relationship between increased cerebral spinal fluid (CSF) ventricular compartments, structural and microstructural dysmaturation, and executive function in patients with congenital heart disease (CHD) is unknown. Here, we leverage a novel machine-learning data-driven technique to delineate interrelationships between CSF ventricular volume, structural and microstructural alterations, clinical risk factors, and sub-domains of executive dysfunction in adolescent CHD patients. We trained random forest regression models to predict measures of executive function (EF) from the NIH Toolbox, the Delis-Kaplan Executive Function System (D-KEFS), and the Behavior Rating Inventory of Executive Function (BRIEF) and across three subdomains of EF - mental flexibility, working memory, and inhibition. We estimated the best parameters for the random forest algorithm via a randomized grid search of parameters using 10-fold cross-validation on the training set only. The best parameters were then used to fit the model on the full training set and validated on the test set. Algorithm performance was measured using root-mean squared-error (RMSE). As predictors, we included patient clinical variables, perioperative clinical measures, microstructural white matter (diffusion tensor imaging- DTI), and structural volumes (volumetric magnetic resonance imaging- MRI). Structural white matter was measured using along-tract diffusivity measures of 13 inter-hemispheric and cortico-association fibers. Structural volumes were measured using FreeSurfer and manual segmentation of key structures. Variable importance was measured by the average Gini-impurity of each feature across all decision trees in which that feature is present in the model, and functional ontology mapping (FOM) was used to measure the degree of overlap in feature importance for each EF subdomain and across subdomains. We found that CSF structural properties (including increased lateral ventricular volume and reduced choroid plexus volumes) in conjunction with proximate cortical projection and paralimbic-related association white matter tracts that straddle the lateral ventricles and distal paralimbic-related subcortical structures (basal ganglia, hippocampus, cerebellum) are predictive of two-specific subdomains of executive dysfunction in CHD patients: cognitive flexibility and inhibition. These findings in conjunction with combined RF models that incorporated clinical risk factors, highlighted important clinical risk factors, including the presence of microbleeds, altered vessel volume, and delayed PDA closure, suggesting that CSF-interstitial fluid clearance, vascular pulsatility, and glymphatic microfluid dynamics may be pathways that are impaired in CHD, providing mechanistic information about the relationship between CSF and executive dysfunction.

Regional changes in brain apparent diffusion coefficient in fetuses with complex congenital heart disease and normal pregnancy assessed using diffusion-weighted imaging

Objectives

To explore changes in brain apparent diffusion coefficient (ADC) in normal fetuses and fetuses with complex congenital heart disease (CHD) during the second and early third trimesters.

Methods

This single-center prospective study was conducted from May 2019 through October 2021. We measured and compared the mean ADC values between 23 fetuses with CHD and 27 gestational age (GA)-matched controls using covariance analyses. ADC density plots and histograms were used to compare brain characteristics. False-discovery rates (FDR, α = 0.05) correction was used for multiple testing.

Results

The mean ADC in the frontal white matter, temporal white matter, parietal white matter, occipital white matter, cerebellar hemisphere, central area of the centrum semiovale, basal ganglia region, thalamus, and pons were not significantly different (all p > 0.05). Based on histogram analysis, there were no significant differences between the controls and fetuses with CHD after FDR correction. However, the ADC density plots showed significant heterogeneity between the controls and fetuses with CHD.

Conclusion

The mean ADC values and ADC histogram analysis did not differ between the CHD and normal groups. The ADC density plots may provide supplementary information and improve the sensitivity for detecting early brain changes in fetuses with CHD.

Structural Brain Alterations and Their Associations With Function in Children, Adolescents, and Young Adults With Congenital Heart Disease

Most neonates who receive surgery for complex congenital heart disease (CHD) will survive well into adulthood, however, many of them will face functional challenges at one point during their life as a consequence of their atypical neurodevelopment. Recent advances in neuroscience and the increasing accessibility of magnetic resonance imaging have allowed numerous studies to identify the nature and extent of the brain alterations that are particular to survivors with CHD. Nevertheless, and considering that the range of outcomes is broad in this population, the functional consequences of these brain differences is not always evident. In this review, we summarize the present state of knowledge regarding the structure-function relationships evaluated in children, adolescents, and young adults with CHD using structural magnetic resonance imaging. Overall smaller total and regional brain volume, as well as lower fractional anisotropy in numerous brain regions, were frequently associated with lower cognitive outcomes including executive functioning and memory in adolescents and young adults with CHD. However, we identify several gaps in knowledge including the limited number of prospective investigations involving neonatal imaging and follow-up during childhood or adolescence, as well as the need for studies that evaluate a broader range of functional outcomes and not only the cognitive abilities. Future interdisciplinary investigations using multimodal imaging techniques could help address these gaps.

Regional impairment of deep gray matter perfusion in neonates with congenital heart disease revealed by arterial spin labeling MRI

The present study examined deep gray matter perfusion in neonates with congenital heart disease (CHD) with arterial spin labeling magnetic resonance imaging preoperatively. We found that neonates with cyanotic CHD showed lower right thalamus compared with controls and lower right basal ganglia perfusion compared with acyanotic CHD. When the CHD group was assessed as a whole, it showed slightly decreased left thalamus perfusion compared with controls. The results suggest that cardiac physiology plays a crucial part in changes in regional cerebral perfusion. Perfusion with arterial spin labeling may be a useful marker of high risk for impaired cerebral blood flow auto-regulation and cerebral hypoperfusion in neonates with CHD.

Effect of Maternal Antidepressant Use During the Pre-pregnancy/Early Pregnancy Period on Congenital Heart Disease: A Prospective Cohort Study in Central China

Background

With the increase in maternal antidepressant prescribing before/during pregnancy, concerns about the safety of antidepressants have come into focus. The purpose of this study was to explore the association between maternal antidepressant use before pregnancy/in early pregnancy and the risk of congenital heart disease (CHD) in children, and to provide a scientific basis for clinical safety of antidepressant use.

Methods

The prospective cohort study ultimately included 34,104 singleton pregnancies. Modified Poisson regression model with robust error variances was used to evaluate RRs and 95% confidence intervals (CIs) for the risk of CHD in offspring exposed to maternal antidepressant in the 3 months before pregnancy and early pregnancy. In addition, sensitivity analysis was further performed to explore the robustness of the results.

Results

In this study, the maternal antidepressant exposure rate was 2.83% in the 3 months before pregnancy, 2.42% in early pregnancy, and the incidence of CHD was 8.973 per 1,000 live births. We found that maternal antidepressant use in the 3 months before pregnancy and early pregnancy were all associated with an increased risk of CHD, ~2.54 times and 2.87 times, respectively, of non-use of antidepressants after adjusting for potential confounders. This association was also found in CHD specific phenotypic analysis. Of these, offspring whose mothers were exposed to antidepressants in the 3 months before pregnancy had the highest risk of transposition of the great arteries (aOR = 5.50, 95% CI: 1.91–15.88). The offspring of mothers exposed to antidepressants in early pregnancy had the highest risk of developing ventricular septal defect (aOR = 4.80, 95% CI: 2.50–9.24). Sensitivity analysis verified the stability of the results.

Conclusions

Maternal antidepressant use in the 3 months before pregnancy and early pregnancy were all associated with an increased risk of CHD in their offspring. In order to reduce the risk of teratogenesis, we recommend that pregnant women prepare for pregnancy after their condition improves or receive the minimum effective dose of medication.

Cerebellar and Prefrontal Structures Associated With Executive Functioning in Pediatric Patients With Congenital Heart Defects

Objective

Children, adolescents, and young adults with congenital heart defects (CHD) often display executive dysfunction. We consider the prefrontal and cerebellar brain structures as mechanisms for executive dysfunction among those with CHD.

Methods

55 participants with CHD (M age = 13.93) and 95 healthy controls (M age = 13.13) completed magnetic resonance imaging (MRI) of the brain, from which we extracted volumetric data on prefrontal and cerebellar regions. Participants also completed neuropsychological tests of executive functioning; their parents completed ratings of their executive functions.

Results

Compared to healthy controls, those with CHD had smaller cerebellums and lateral, medial, and orbital prefrontal regions, they performed more poorly on tests of working memory, inhibitory control, and mental flexibility, and their parents rated them as having poorer executive functions across several indices. Across both groups, there were significant correlations for cerebellar and/or prefrontal volumes with cognitive assessments of working memory, mental flexibility, and inhibitory control and with parent-completed ratings of task initiation, working memory, and planning/organization. Greater prefrontal volumes were associated with better working memory, among those with larger cerebellums (with group differences based on the measure and the prefrontal region). Greater prefrontal volumes were related to better emotional regulation only among participants with CHD with smaller cerebellar volumes, and with poorer inhibition and emotional regulation only among healthy controls with larger cerebellar volumes.

Conclusion

The cerebellum not only contributes to executive functioning among young individuals with CHD but may also modulate the relationships between prefrontal regions and executive functioning differently for pediatric patients with CHD vs. health controls.

The Effect of Abnormal Regional Homogeneity and Spontaneous Low-Frequency Brain Activity on Lower Cognitive Ability: A Cross-Sectional Study on Postoperative Children With Tetralogy of Fallot

Despite intracardiac malformation correction, children with Tetralogy of Fallot (TOF) may still suffer from brain injury. This cross-sectional study was primarily designed to determine the relationship between blood oxygenation level-dependent (BOLD) signal changes after surgery and cognition in school-aged children with TOF. To evaluate the differences between TOF children (n = 9) and healthy children (n = 9), resting-state functional magnetic resonance imaging (rs-fMRI) and the Wechsler Intelligence Scale for Children–Chinese revised edition (WISC-CR) were conducted in this study. The results showed that TOF children had a lower full-scale intelligence quotient (FSIQ, 95.444 ± 5.354, p = 0.022) and verbal intelligence quotient (VIQ, 92.444 ± 4.708, p = 0.003) than healthy children (FSIQ = 118.500 ± 4.330;VIQ = 124.250 ± 4.404), and that significant differences in regional homogeneity (ReHo) and amplitude of low-frequency fluctuation (ALFF) existed between the two groups. Besides, VIQ had significantly positive correlations with the decreased ALFF value of the middle inferior occipital gyrus (MIOG, beta = 0.908, p = 0.012) after fully adjusting for all covariates. In addition, elevated ReHo values of the left and right precuneus were positively related to ALFF in the MIOG. This study revealed that brain injury substantially influences neural activity and cognition in postoperative TOF children, providing direct evidence of an association between BOLD signal changes and the VIQ and prompting further attention to language development in TOF children.

Harnessing the Power of Stem Cell Models to Study Shared Genetic Variants in Congenital Heart Diseases and Neurodevelopmental Disorders

Advances in human pluripotent stem cell (hPSC) technology allow one to deconstruct the human body into specific disease-relevant cell types or create functional units representing various organs. hPSC-based models present a unique opportunity for the study of co-occurring disorders where “cause and effect” can be addressed. Poor neurodevelopmental outcomes have been reported in children with congenital heart diseases (CHD). Intuitively, abnormal cardiac function or surgical intervention may stunt the developing brain, leading to neurodevelopmental disorders (NDD). However, recent work has uncovered several genetic variants within genes associated with the development of both the heart and brain that could also explain this co-occurrence. Given the scalability of hPSCs, straightforward genetic modification, and established differentiation strategies, it is now possible to investigate both CHD and NDD as independent events. We will first overview the potential for shared genetics in both heart and brain development. We will then summarize methods to differentiate both cardiac & neural cells and organoids from hPSCs that represent the developmental process of the heart and forebrain. Finally, we will highlight strategies to rapidly screen several genetic variants together to uncover potential phenotypes and how therapeutic advances could be achieved by hPSC-based models.

Long-Term Neurodevelopmental Outcomes of Children with Congenital Heart Defects

OBJECTIVE

To assess whether children with symptomatic congenital heart defects (CHDs) at birth (cyanosis and/or heart failure) are at greater risk of adverse neurodevelopmental outcomes at 8 years of age.

STUDY DESIGN

From a prospective population-based cohort study of newborns with CHDs (EPICARD), we included 473 children with available neurodevelopmental assessments at 8 years of age. We grouped the CHD based on symptoms at birth and need for early neonatal intervention. Ventricular septal defects that closed spontaneously within the first year of life were considered the control group. Neurodevelopmental outcomes were assessed using the Kauffman Assessment Battery Test for Children, Second Edition, for IQ (mean 100 ± 15), and the Developmental NEuroPSYchological Assessment Battery, Second Edition, for detailed assessment of specific neurocognitive domains (mean 10 ± 3). Multivariable regression analysis was used to compare the outcomes across the CHD groups after considering potentially confounding variables.

RESULTS

Compared with the control group, children with cyanotic CHD without heart failure had lower scores for IQ, -7.2 (95% CI -13.4 to -1.2). Children with noncyanotic CHD with heart failure had lower scores in the specific domains of language -1.5 (95% CI -2.2 to -0.7), and memory and learning -1.3 (95% CI -2.4; -0.3). Those with both cyanotic CHD and heart failure had lower scores for IQ, -7.6 (95% CI -13.5 to -1.8), as well as the specific domains of language and memory and learning, -2.0 (95% CI -2.9 to -1.0) and -1.1 (95% CI -2.3 to -0.1), respectively.

CONCLUSIONS

Children with symptomatic CHD at birth are at greater risk of adverse neurodevelopmental outcomes at 8 years of age, with the greatest risk for those who were born with both cyanosis and heart failure.

Is fetal MRI ready for neuroimaging prime time? An examination of progress and remaining areas for development

A major challenge in designing large-scale, multi-site studies is developing a core, scalable protocol that retains the innovation of scientific advances while also lending itself to the variability in experience and resources across sites. In the development of a common Healthy Brain and Child Development (HBCD) protocol, one of the chief questions is "is fetal MRI ready for prime-time?" While there is agreement about the value of prenatal data obtained non-invasively through MRI, questions about practicality abound. There has been rapid progress over the past years in fetal and placental MRI methodology but there is uncertainty about whether the gains afforded outweigh the challenges in supporting fetal MRI protocols at scale. Here, we will define challenges inherent in building a common protocol across sites with variable expertise and will propose a tentative framework for evaluation of design decisions. We will compare and contrast various design considerations for both normative and high-risk populations, in the setting of the post-COVID era. We will conclude with articulation of the benefits of overcoming these challenges and would lend to the primary questions articulated in the HBCD initiative.

Impact of Cardiopulmonary Bypass on Neurogenesis and Cortical Maturation

OBJECTIVE

Neurodevelopmental delays and frontal lobe cortical dysmaturation are widespread among children with congenital heart disease (CHD). The subventricular zone (SVZ) is the largest pool of neural stem/progenitor cells in the postnatal brain. Our aim is to determine the effects of cardiopulmonary bypass (CPB) on neurogenesis and cortical maturation in piglets whose SVZ development is similar to human infants.

METHODS

Three-week-old piglets (n = 29) were randomly assigned to control (no surgery), mild-CPB (34°C full flow for 60 minutes) and severe-CPB groups (25°C circulatory-arrest for 60 minutes). The SVZ and frontal lobe were analyzed with immunohistochemistry 3 days and 4 weeks postoperatively. MRI of the frontal lobe was used to assess cortical development.

RESULTS

SVZ neurogenic activity was reduced up to 4 weeks after both mild and severe CPB-induced insults. CPB also induced decreased migration of young neurons to the frontal lobe, demonstrating that CPB impairs postnatal neurogenesis. MRI 4 weeks after CPB displayed a decrease in gyrification index and cortical volume of the frontal lobe. Cortical fractional anisotropy was increased after severe CPB injury, indicating a prolonged deleterious impact of CPB on cortical maturation. Both CPB-induced insults displayed a significant change in densities of three major inhibitory neurons, suggesting excitatory-inhibitory imbalance in the frontal cortex. In addition, different CPB insults altered different subpopulations of inhibitory neurons.

INTERPRETATION

Our results provide novel insights into cellular mechanisms contributing to CHD-induced neurological impairments. Further refinement of CPB hardware and techniques is necessary to improve long-term frontal cortical dysmaturation observed in children with CHD. ANN NEUROL 2021.

Contribution of Congenital Heart Disorders Associated With Copy Number Variants in Mediating Risk for Brain Developmental Disorders: Evidence From 20-Year Retrospective Cohort Study

Rare pathogenic copy number variants (CNVs) are genetic rearrangements that have been associated with an increased risk for congenital heart disorders (CHDs). However, the association of CNVs with atypical brain development, leading to neurodevelopmental disorders (NDDs), in the presence of CHDs remains unclear. We attempted to explore this association by establishing the prevalence and burden of CNVs associated with CHD in a Welsh population and by studying the effect of rare CNVs associated with CHDs in mediating the risk of NDDs. Toward this goal, we analyzed data from the Congenital Anomaly Register for Wales (CARIS), referred from hospitals in Wales between 1998 and 2018, which included 1,113 subjects in total. Of these, 785 subjects were included in the study following application of the exclusion criteria, and a total of 28 rare CNVs associated with CHD were analyzed. The findings from this cohort study identified 22q11.2 deletion as the most prominent CNV across the cohort. Our data demonstrates that the survival rate of the cohort after 3 years was 99.9%, and mortality fell significantly between 1 and 2 years and between 2 and 3 years [F_(1,27) = 10, p = 0.0027; F_(1,27) = 5.8, p = 0.0222]. Importantly, the data set revealed a positive correlation between the incidence of congenital heart disease and the incidence of neurodevelopmental abnormalities in patients with CNVs across the whole cohort [95% CI (0.4062, 0.8449), p < 0.0001, r = 0.6829]. Additionally, we identified significant CNVs that result in the co-morbidity of CHD and NDD and show that septal defects and global developmental delay are major congenital defects. Further research should identify a common molecular mechanism leading to the phenotypic comorbidity of CHDs and NDDs, arising from a common CNV, which can have an implication for improving risk classification and for fetal neuroprotection strategies in the affected children and in precision medicine.

The Roles of Reduced Folate Carrier-1 (RFC1) A80G (rs1051266) Polymorphism in Congenital Heart Disease: A Meta-Analysis

Background

We performed the present study to better elucidate the correlation of reduced folate carrier-1 (RFC1) A80G (rs1051266) polymorphism with the risk of congenital heart disease (CHD).

Material/Methods

According to the designed search strategy, a systematic literature search was performed through the PubMed, Cochrane Library, Web of Science, EMBASE, CNKI, VIP, and Wan Fang databases to collect published case-control studies on the correlation between RFC1 A80G polymorphism and CHD. All relevant studies up to October 1, 2019 were identified. The odds ratio (OR) and 95% confidence interval (CI) of the genotype distribution were used as the effect indicators.

Results

A total of 6 eligible studies was finally included in our meta-analysis, including 724 children with CHD, 760 healthy children, 258 mothers of the children with CHD, and 334 mothers of healthy control children. The meta-analysis revealed that for fetal analysis, only in the heterozygous model (GA vs GG, OR=1.36, 95% CI [1.06, 1.75], P=0.02) was RFC1 A80G polymorphism associated with risk of CHD. In maternal analysis, 3 genetic models of RFC1 A80G polymorphism increased the risk of CHD: the allelic model (A vs G, OR=1.36, 95% CI [1.07, 1.71], P=0.01), the homozygote model (AA vs GG, OR=2.99, 95%CI [1.06, 8.41], P=0.04), and the dominance model (GA+AA vs GG, OR=1.53, 95%CI [1.08, 2.16], P=0.02).

Conclusions

The maternal RFC1 A80G polymorphism has a strong correlation with CHD. Compared with the G allele, the A allele increases the risk of CHD by 0.36-fold.

Infants with congenital heart defects have reduced brain volumes

Children with congenital heart defects (CHDs) have increased risk of cognitive disabilities for reasons not fully understood. Previous studies have indicated signs of disrupted fetal brain growth from mid-gestation measured with ultrasound and magnetic resonance imaging (MRI) and infants with CHDs have decreased brain volumes at birth. We measured the total and regional brain volumes of infants with and without CHDs using MRI to investigate, if certain areas of the brain are at particular risk of disrupted growth. MRI brain volumetry analyses were performed on 20 infants; 10 with- (postmenstrual age 39–54 weeks, mean 44 weeks + 5 days) and 10 without CHDs (postmenstrual age 39–52 weeks, mean 43 weeks + 5 days). In six infants with- and eight infants without CHDs grey and white matter were also differentiated. Infants with CHDs had smaller brains (48 ml smaller; 95% CI, 6.1–90; p = 0.03), cerebrums (37.8 ml smaller; 95% CI, 0.8–74.8; p = 0.04), and cerebral grey matter (25.8 ml smaller; 95% CI, 3.5–48; p = 0.03) than infants without CHD. Brain volume differences observed within weeks after birth in children with CHDs confirm that the brain impact, which increase the risk of cognitive disabilities, may begin during pregnancy.

Outcomes of Preterm Infants With Congenital Heart Defects After Early Surgery: Defining Risk Factors at Different Time Points During Hospitalization

Background: Compared with those born at term gestation, infants with complex congenital heart defects (CCHD) who were delivered before 37 weeks gestational age and received neonatal open-heart surgery (OHS) have poorer neurodevelopmental outcomes in early childhood. We aimed to describe the growth, disability, functional, and neurodevelopmental outcomes in early childhood of preterm infants with CCHD after neonatal OHS. Prediction models were evaluated at various timepoints during hospitalization which could be useful in the management of these infants. Study Design: We studied all preterm infants with CCHD who received OHS within 6 weeks of corrected age between 1996 and 2016. The Western Canadian Complex Pediatric Therapies Follow-up Program completed multidisciplinary comprehensive neurodevelopmental assessments at 2-year corrected age at the referral-site follow-up clinics. We collected demographic and acute-care clinical data, standardized age-appropriate outcome measures including physical growth with calculated z-scores; disabilities including cerebral palsy, visual impairment, permanent hearing loss; adaptive function (Adaptive Behavior Assessment System-II); and cognitive, language, and motor skills (Bayley Scales of Infant and Toddler Development-III). Multiple variable logistic or linear regressions determined predictors displayed as Odds Ratio (OR) or Effect Size (ES) with 95% confidence intervals. Results: Of 115 preterm infants (34 ± 2 weeks gestation, 2,339 ± 637 g, 64% males) with CCHD and OHS, there were 11(10%) deaths before first discharge and 21(18%) deaths by 2-years. Seven (6%) neonates had cerebral injuries, 7 had necrotizing enterocolitis; none had retinopathy of prematurity. Among 94 survivors, 9% had cerebral palsy and 6% had permanent hearing loss, with worse outcomes in those with syndromic diagnoses. Significant predictors of mortality included birth weight z-score [OR 0.28(0.11,0.72), P = 0.008], single-ventricle anatomy [OR 5.92(1.31,26.80), P = 0.021], post-operative ventilation days [OR 1.06(1.02,1.09), P = 0.007], and cardiopulmonary resuscitation [OR 11.58 (1.97,68.24), P = 0.007]; for adverse functional outcome in those without syndromic diagnoses, birth weight 2,000-2,499 g [ES -11.60(-18.67, -4.53), P = 0.002], post-conceptual age [ES -0.11(-0.22,0.00), P = 0.044], post-operative lowest pH [ES 6.75(1.25,12.25), P = 0.017], and sepsis [ES -9.70(-17.74, -1.66), P = 0.050]. Conclusions: Our findings suggest preterm neonates with CCHD and early OHS had significant mortality and morbidity at 2-years and were at risk for cerebral palsy and adverse neurodevelopment. This information may be important for management, parental counseling and the decision-making process.

Antenatal and Perioperative Mechanisms of Global Neurological Injury in Congenital Heart Disease

Congenital heart defects (CHD) is one of the most common types of birth defects. Thanks to advances in surgical techniques and intensive care, the majority of children with severe forms of CHD survive into adulthood. However, this increase in survival comes with a cost. CHD survivors have neurological functioning at the bottom of the normal range. A large spectrum of central nervous system dysmaturation leads to the deficits seen in critical CHD. The heart develops early during gestation, and CHD has a profound effect on fetal brain development for the remainder of gestation. Term infants with critical CHD are born with an immature brain, which is highly susceptible to hypoxic-ischemic injuries. Perioperative blood flow disturbances due to the CHD and the use of cardiopulmonary bypass or circulatory arrest during surgery cause additional neurological injuries. Innate patient factors, such as genetic syndromes and preterm birth, and postoperative complications play a larger role in neurological injury than perioperative factors. Strategies to reduce the disability burden in critical CHD survivors are urgently needed.

Neuropathology of Congenital Heart Disease in an Inpatient Autopsy Cohort 2000-2017

Background As a result of medical and surgical advancements in the management of congenital heart disease (CHD), survival rates have improved substantially, which has allowed the focus of CHD management to shift toward neurodevelopmental outcomes. Previous studies of the neuropathology occurring in CHD focused on cases preceding 1995 and reported high rates of white matter injury and intracranial hemorrhage, but do not reflect improvements in management of CHD in the past 2 decades. The purpose of this study is therefore to characterize the neuropathological lesions identified in subjects dying from CHD in a more-recent cohort from 2 institutions. Methods and Results We searched the autopsy archives at 2 major children's hospitals for patients with cyanotic congenital cardiac malformations who underwent autopsy. We identified 50 cases ranging in age from 20 gestational weeks to 46 years. Acquired neuropathological lesions were identified in 60% (30 of 50) of subjects upon postmortem examination. The most common lesions were intracranial hemorrhage, most commonly subarachnoid (12 of 50; 24%) or germinal matrix (10 of 50; 20%), hippocampal injuries (10 of 50; 20%), and diffuse white matter gliosis (8 of 50; 16%). Periventricular leukomalacia was rare (3 of 50). Twenty-six subjects underwent repair or palliation of their lesions. Of the 50 subjects, 60% (30 of 50) had isolated CHD, whereas 24% (12 of 50) were diagnosed with chromosomal abnormalities (trisomy 13, 18, chromosomal deletions, and duplications) and 16% (8/50) had multiple congenital anomalies. Conclusions In the modern era of pediatric cardiology and cardiac surgery, intracranial hemorrhage and microscopic gray matter hypoxic-ischemic lesions are the dominant neuropathological lesions identified in patients coming to autopsy. Rates of more severe focal lesions, particularly periventricular leukomalacia, have decreased compared with historical controls.

Impact of Mesenchymal Stromal Cell Delivery Through Cardiopulmonary Bypass on Postnatal Neurogenesis

BACKGROUND

Neurodevelopmental impairment is an important challenge for survivors after neonatal surgery with cardiopulmonary bypass (CPB). The subventricular zone, where most neural stem/progenitors originate, plays a critical role in cortical maturation of the frontal lobe. Promoting neurogenesis in the subventricular zone is therefore a potential therapeutic target for preserving cortical growth. Mesenchymal stromal cells (MSCs) promote endogenous regeneration in the rodent brain. We investigated the impact of MSC delivery through CPB on neural stem/progenitor cells and neuroblasts (ie, young neurons) in the piglet subventricular zone.

METHODS

Two-week-old piglets (n = 12) were randomly assigned to one of three groups: (1) control, (2) deep hypothermic circulatory arrest, and (3) circulatory arrest, followed by MSC administration. MSCs (10 × 10⁶ per kg) were delivered through CPB during the rewarming period. Neural stem/progenitors, proliferating cells, and neuroblasts were identified with immunohistochemistry at 3 hours after CPB.

RESULTS

CPB-induced insults caused an increased proliferation of neural stem/progenitors (P < .05). MSC delivery reduced the acute proliferation. MSC treatment increased the number of neuroblasts in the outer region of the subventricular zone (P < .05) where they form migrating chains toward the frontal lobe. Conversely, the thickness of the neuroblast-dense band along the lateral ventricle was reduced after treatment (P < .05). These findings suggest that MSC treatment changes neuroblast distribution within the subventricular zone.

CONCLUSIONS

MSC delivery through CPB has the potential to mitigate effects of CPB on neural stem/progenitor cells and to promote migration of neuroblasts. Further investigation is necessary to determine the long-term effect of MSC treatment during CPB on postnatal neurogenesis.

Treatment With Tetrahydrobiopterin Improves White Matter Maturation in a Mouse Model for Prenatal Hypoxia in Congenital Heart Disease

Background Reduced oxygen delivery in congenital heart disease causes delayed brain maturation and white matter abnormalities in utero. No treatment currently exists. Tetrahydrobiopterin (BH4) is a cofactor for neuronal nitric oxide synthase. BH4 availability is reduced upon NOS activation, such as during hypoxic conditions, and leads to toxin production. We hypothesize that BH4 levels are depleted in the hypoxic brain and that BH4 replacement therapy mitigates the toxic effects of hypoxia on white matter. Methods and Results Transgenic mice were used to visualize oligodendrocytes. Hypoxia was introduced during a period of white matter development equivalent to the human third trimester. BH4 was administered during hypoxia. BH4 levels were depleted in the hypoxic brain by direct quantification (n=7-12). The proliferation (n=3-6), apoptosis (n=3-6), and developmental stage (n=5-8) of oligodendrocytes were determined immunohistologically. Total oligodendrocytes increased after hypoxia, consistent with hypoxia-induced proliferation seen previously; however, mature oligodendrocytes were less prevalent in hypoxia, and there was accumulation of immature oligodendrocytes. BH4 treatment improved the mature oligodendrocyte number such that it did not differ from normoxia, and accumulation of immature oligodendrocytes was not observed. These results persisted beyond the initial period of hypoxia (n=3-4). Apoptosis increased with hypoxia but decreased with BH4 treatment to normoxic levels. White matter myelin levels decreased following hypoxia by western blot. BH4 treatment normalized myelination (n=6-10). Hypoxia worsened sensory-motor coordination on balance beam tasks, and BH4 therapy normalized performance (n=5-9). Conclusions Suboptimal BH4 levels influence hypoxic white matter abnormalities. Repurposing BH4 for use during fetal brain development may limit white matter dysmaturation in congenital heart disease.