Prenatal head growth and white matter injury in hypoplastic left heart syndrome

Mitotic Block and Epigenetic Repression Underlie Neurodevelopmental Defects and Neurobehavioral Deficits in Congenital Heart Disease

Poor neurodevelopment is often observed with congenital heart disease (CHD), especially with mutations in chromatin modifiers. Here analysis of mice with hypoplastic left heart syndrome (HLHS) arising from mutations in Sin3A associated chromatin modifier Sap130 , and adhesion protein Pcdha9, revealed neurodevelopmental and neurobehavioral deficits reminiscent of those in HLHS patients. Microcephaly was associated with impaired cortical neurogenesis, mitotic block, and increased apoptosis. Transcriptional profiling indicated dysregulated neurogenesis by REST, altered CREB signaling regulating memory and synaptic plasticity, and impaired neurovascular coupling modulating cerebral blood flow. Many neurodevelopmental/neurobehavioral disease pathways were recovered, including autism and cognitive impairment. These same pathways emerged from genome-wide DNA methylation and Sap130 chromatin immunoprecipitation sequencing analyses, suggesting epigenetic perturbation. Mice with Pcdha9 mutation or forebrain-specific Sap130 deletion without CHD showed learning/memory deficits and autism-like behavior. These novel findings provide mechanistic insights indicating the adverse neurodevelopment in HLHS may involve cell autonomous/nonautonomous defects and epigenetic dysregulation and suggest new avenues for therapy.

Angiogenic imbalance in maternal and cord blood is associated with neonatal birth weight and head circumference in pregnancies with major fetal congenital heart defect

OBJECTIVES

To ascertain whether abnormalities in neonatal head circumference and/or body weight are associated with levels of angiogenic/antiangiogenic factors in the maternal and cord blood of pregnancies with a congenital heart defect (CHD) and to assess whether the specific type of CHD influences this association.

METHODS

This was a multicenter case-control study of women carrying a fetus with major CHD. Recruitment was carried out between June 2010 and July 2018 at four tertiary care hospitals in Spain. Maternal venous blood was drawn at study inclusion and at delivery. Cord blood samples were obtained at birth when possible. Placental growth factor (PlGF), soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng) were measured in maternal and cord blood. Biomarker concentrations in the maternal blood were expressed as multiples of the median (MoM).

RESULTS

PlGF, sFlt-1 and sEng levels were measured in the maternal blood in 237 cases with CHD and 260 healthy controls, and in the cord blood in 150 cases and 56 controls. Compared with controls, median PlGF MoM in maternal blood was significantly lower in the CHD group (0.959 vs 1.022; P < 0.0001), while median sFlt-1/PlGF ratio MoM was significantly higher (1.032 vs 0.974; P = 0.0085) and no difference was observed in sEng MoM (0.981 vs 1.011; P = 0.4673). Levels of sFlt-1 and sEng were significantly higher in cord blood obtained from fetuses with CHD compared to controls (mean ± standard error of the mean, 447 ± 51 vs 264 ± 20 pg/mL; P = 0.0470 and 8.30 ± 0.92 vs 5.69 ± 0.34 ng/mL; P = 0.0430, respectively). Concentrations of sFlt-1 and the sFlt-1/PlGF ratio in the maternal blood at study inclusion were associated negatively with birth weight and head circumference in the CHD group. The type of CHD anomaly (valvular, conotruncal or left ventricular outflow tract obstruction) did not appear to alter these findings.

CONCLUSIONS

Pregnancies with fetal CHD have an antiangiogenic profile in maternal and cord blood. This imbalance is adversely associated with neonatal head circumference and birth weight. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Impact of Congenital Heart Defects on the Developing Brain

OBJECTIVES

Congenital heart defects (CHD) are responsible for neurodevelopmental delays that were initially attributed to brain injury resulting from cardiac surgery. However, prenatal imaging have shown that brain anomalies are present at birth. The aim of this study was to assess in utero brain injuries before birth in fetuses/neonates with congenital cardiopathies.

METHODS

A complete autopsy evaluation with detailed study of the cardiopathy and neuropathological study was performed in 40 fetuses/neonates. Syndromic congenital cardiopathies were excluded because of the potential other causes of brain injury. The patients were classified into two groups according to their term at death.

RESULTS

Statistical analyses indicated the mean brain weight was not significantly different between subjects with different morphological types of congenital cardiopathies. However, the brain weight was at or below the fifth percentile in most third-trimester subjects compared to normal brain weight in second-trimester subjects. Low brain weight in third-trimester subjects was also associated with frequent lesions similar to those described in preterm infants, with a particular involvement of white matter and its components.

CONCLUSIONS

These observations allowed us to establish the timing and impact of prenatal neuropathological lesions on brain development, and to correlate them with imaging data reported in the literature.

Chronic hypoxemia induces mitochondrial respiratory complex gene expression in the fetal sheep brain

Objective

The molecular pathways underlying hypoxemia-induced alterations in neurodevelopment of infants with congenital heart disease have not been delineated. We used transcriptome analysis to investigate differential gene expression induced by hypoxemia in an ovine artificial-womb model.

Methods

Mid-gestation fetal sheep (median [interquartile range] 109 [107-112] days' gestation) were cannulated via the umbilical vessels, attached to a pumpless, low-resistance oxygenator circuit, and incubated in a sterile, fluid environment for 22 [21-23] days. Fetuses were maintained with an oxygen delivery of 20-25 mL/kg/min (normoxemia, n = 3) or 14-16 mL/kg/min (hypoxemia, n = 4). Transcriptional profiling by RNA sequencing was carried out on left frontal brains and hypoxemia-regulated genes were identified by differential gene expression analysis.

Results

A total of 228 genes whose expression was up or down regulated by ≥1.5-fold (false discovery rate ≤0.05) were identified. The majority of these genes were induced in hypoxemic animals compared to normoxemic controls, and functional enrichment analysis identified respiratory electron transport as a pathway strongly upregulated in the brain during chronic hypoxemia. Further examination of hypoxemia-induced genes showed robust induction of all 7 subunits of the mitochondrial NADH:ubiquinone oxidoreductase (complex I). Other hypoxemia-induced genes included cytochrome B, a component of complex III, and ATP6, ATP8, both of which are components of complex V.

Conclusions

Chronic fetal hypoxemia leads to upregulation of multiple mitochondrial respiratory complex genes critical for energy production and reactive oxygen species generation, including complex I. These data provide valuable insight into potential pathways involved in chronic hypoxemia-induced neuropathology and offers potential therapeutic targets for fetal neuroprotection in fetuses with congenital heart defects.

Novel Protein-Protein Interactions Highlighting the Crosstalk between Hypoplastic Left Heart Syndrome, Ciliopathies and Neurodevelopmental Delays

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) affecting 1 in 5000 newborns. We constructed the interactome of 74 HLHS-associated genes identified from a large-scale mouse mutagenesis screen, augmenting it with 408 novel protein-protein interactions (PPIs) using our High-Precision Protein-Protein Interaction Prediction (HiPPIP) model. The interactome is available on a webserver with advanced search capabilities. A total of 364 genes including 73 novel interactors were differentially regulated in tissue/iPSC-derived cardiomyocytes of HLHS patients. Novel PPIs facilitated the identification of TOR signaling and endoplasmic reticulum stress modules. We found that 60.5% of the interactome consisted of housekeeping genes that may harbor large-effect mutations and drive HLHS etiology but show limited transmission. Network proximity of diabetes, Alzheimer's disease, and liver carcinoma-associated genes to HLHS genes suggested a mechanistic basis for their comorbidity with HLHS. Interactome genes showed tissue-specificity for sites of extracardiac anomalies (placenta, liver and brain). The HLHS interactome shared significant overlaps with the interactomes of ciliopathy- and microcephaly-associated genes, with the shared genes enriched for genes involved in intellectual disability and/or developmental delay, and neuronal death pathways, respectively. This supported the increased burden of ciliopathy variants and prevalence of neurological abnormalities observed among HLHS patients with developmental delay and microcephaly, respectively.

MRI characterization of hemodynamic patterns of human fetuses with cyanotic congenital heart disease

OBJECTIVES

To characterize, using magnetic resonance imaging (MRI), the distribution of blood flow and oxygen transport in human fetuses with subtypes of congenital heart disease (CHD) that present with neonatal cyanosis.

METHODS

Blood flow was measured in the major vessels of 152 late-gestation human fetuses with CHD and 40 gestational-age-matched normal fetuses, using cine phase-contrast MRI. Oxygen saturation (SaO₂ ) was measured in the major vessels of 57 fetuses with CHD and 40 controls.

RESULTS

Compared with controls, we found lower combined ventricular output in fetuses with single-ventricle physiology, with the lowest being observed in fetuses with severe forms of Ebstein's anomaly. Obstructive lesions of the left or right heart were associated with increased flow across the contralateral side. Pulmonary blood flow was reduced in fetuses with Ebstein's anomaly, while those with Ebstein's anomaly and tricuspid atresia had reduced umbilical flow. Flow in the superior vena cava was elevated in fetuses with transposition of the great arteries, normal in fetuses with hypoplastic left heart, tetralogy of Fallot or tricuspid atresia and reduced in fetuses with Ebstein's anomaly. Umbilical vein SaO₂ was reduced in fetuses with hypoplastic left heart or tetralogy of Fallot. Ascending aorta and superior vena cava SaO₂ were reduced in nearly all CHD subtypes.

CONCLUSIONS

Fetuses with cyanotic CHD exhibit profound changes in the distribution of blood flow and oxygen transport, which result in changes in cerebral, pulmonary and placental blood flow and oxygenation. These alterations of fetal circulatory physiology may influence the neonatal course and help account for abnormalities of prenatal growth and development that have been described in newborns with cyanotic CHD. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal brain issues in congenital heart disease

Following the improvements in the clinical management of patients with congenital heart disease (CHD) and their increased survival, neurodevelopmental outcome has become an emerging priority in pediatric cardiology. Large-scale efforts have been made to protect the brain during the postnatal, surgical, and postoperative period; however, the presence of brain immaturity and injury at birth suggests in utero and peripartum disturbances. Over the past decade, there has been considerable interest and investigations on fetal brain growth in the setting of CHD. Advancements in fetal brain imaging have identified abnormal brain development in fetuses with CHD from the macrostructural (brain volumes and cortical folding) down to the microstructural (biochemistry and water diffusivity) scale, with more severe forms of CHD showing worse disturbances and brain abnormalities starting as early as the first trimester. Anomalies in common genetic developmental pathways and diminished cerebral substrate delivery secondary to altered cardiovascular physiology are the forefront hypotheses, but other factors such as impaired placental function and maternal psychological stress have surfaced as important contributors to fetal brain immaturity in CHD. The characterization and timing of fetal brain disturbances and their associated mechanisms are important steps for determining preventative prenatal interventions, which may provide a stronger foundation for the developing brain during childhood.

Pattern of head circumference growth following bidirectional Glenn in infants with single ventricle heart disease

BACKGROUND

Infants with single ventricle congenital heart disease demonstrate increasing head growth after bidirectional Glenn; however, the expected growth trajectory has not been well described.

AIMS

1) We will describe the pattern of head circumference growth in the first year after bidirectional Glenn. 2) We will determine if head growth correlates with motor developmental outcomes approximately 12 months after bidirectional Glenn.

METHODS

Sixty-nine single ventricle patients underwent bidirectional Glenn between 2010 and 2016. Patients with structural brain abnormalities, grade III-IV intra-ventricular haemorrhage, significant stroke, or obstructive hydrocephalus were excluded. Head circumference and body weight measurements from clinical encounters were evaluated. Motor development was measured with Psychomotor Developmental Index of the Bayley Scales of Infant Development, Third Edition. Generalised estimating equations assessed change in head circumference z-scores from baseline (time of bidirectional Glenn) to 12 months post-surgery.

RESULTS

Mean age at bidirectional Glenn was 4.7 (2.3) months and mean head circumference z-score based on population-normed data was -1.13 (95% CI -1.63, -0.63). Head circumference z-score increased to 0.35 (95% CI -0.20, 0.90) (p < 0.0001) 12 months post-surgery. Accelerated head growth, defined as an increase in z-score of >1 from baseline to 12 months post-surgery, was present in 46/69 (66.7%) patients. There was no difference in motor Psychomotor Developmental Index scores between patients with and without accelerated head growth.

CONCLUSION

Single ventricle patients demonstrated a significant increase in head circumference after bidirectional Glenn until 10-12 months post-surgery, at which time growth stabilised. Accelerated head growth did not predict sub-sequent motor developmental outcomes.

Cerebroplacental and Uterine Doppler Indices in Pregnancies Complicated by Congenital Heart Disease of the Fetus

PURPOSE

 Children with congenital heart disease (CHD) are known to have impaired neurodevelopment possibly influenced by altered cerebroplacental hemodynamics antenatally. We compared fetomaternal Doppler patterns in different CHD groups with published normative values during gestation.

MATERIALS AND METHODS

 Retrospective cohort study consisting of 248 CHD fetuses. Subgroups were generated according to the expected ascending aorta oxygen saturation: low portion of high oxygenated umbilical venous (UV) blood (group 1: n = 108), intermediate portion of UV blood due to intracardiac mixing with oxygen poor systemic blood (group 2: n = 103), high (group 3: n = 13) and low portion of UV blood without mixing of blood (group 4: n = 24). Doppler examination included umbilical artery and middle cerebral artery pulsatility index (UA-PI, MCA-PI), cerebroplacental ratio (CPR) and mean uterine artery (mUtA) PI. For mean comparisons at different gestational ages (GA), estimated marginal means from regression models are reported for GA 22 weeks (wks), GA 30 wks and GA 38 wks.

RESULTS

 Z-score transformed values of MCA-PI (zMCA-PI) were significantly lower in group 1 compared to all other subgroups at GA 30 wks (p < 0.05). At 38 wks, group 1 had significantly lower values of zMCA-PI and zCPR compared to groups 2 and 4. Group 1 fetuses showed a significant association between zMCA-PI and zCPR (negative) and GA as well as zmUtA-PI (positive) and GA compared to reference values.

CONCLUSION

 Our data confirm that CHD fetuses have a higher rate of cerebral redistribution in the third trimester. Changes in Doppler patterns were mainly observed in CHD with a low portion of UV blood in the ascending aorta.

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.

Fetal cardiovascular magnetic resonance imaging

Fetal cardiovascular MRI is showing promise as a clinical diagnostic tool in the setting of congenital heart disease when the cardiac anatomy is unresolved by US or when complementary quantitative data on blood flow, oxygen saturation and hematocrit are required to aid in management. Compared with postnatal cardiovascular MRI, prenatal cardiovascular MRI still has some technical limitations. However, ongoing technical advances continue to improve the robustness and usability of fetal cardiovascular MRI. In this review, we provide an overview of the state of the art of fetal cardiovascular MRI and summarize the current focus of clinical application for this versatile technique.

Reduced structural connectivity in cortico-striatal-thalamic network in neonates with congenital heart disease

Impaired brain development has been observed in newborns with congenital heart disease (CHD). We performed graph theoretical analyses and network-based statistics (NBS) to assess global brain network topology and identify subnetworks of altered connectivity in infants with CHD prior to cardiac surgery. Fifty-eight infants with critical/serious CHD prior to surgery and 116 matched healthy controls as part of the developing Human Connectome Project (dHCP) underwent MRI on a 3T system and high angular resolution diffusion MRI (HARDI) was obtained. Multi-tissue constrained spherical deconvolution, anatomically constrained probabilistic tractography (ACT) and spherical-deconvolution informed filtering of tractograms (SIFT2) was used to construct weighted structural networks. Network topology was assessed and NBS was used to identify structural connectivity differences between CHD and control groups. Structural networks were partitioned into core and peripheral nodes, and edges classed as core, peripheral, or feeder. NBS identified one subnetwork with reduced structural connectivity in CHD infants involving basal ganglia, amygdala, hippocampus, cerebellum, vermis, and temporal and parieto-occipital lobe, primarily affecting core nodes and edges. However, we did not find significantly different global network characteristics in CHD neonates. This locally affected sub-network with reduced connectivity could explain, at least in part, the neurodevelopmental impairments associated with CHD.

The Congenital Heart Disease Brain: Prenatal Considerations for Perioperative Neurocritical Care

Altered brain development has been highlighted as an important contributor to adverse neurodevelopmental outcomes in children with congenital heart disease. Abnormalities begin prenatally and include micro- and macrostructural disturbances that lead to an altered trajectory of brain growth throughout gestation. Recent progress in fetal imaging has improved understanding of the neurobiological mechanisms and risk factors for impaired fetal brain development. The impact of the prenatal environment on postnatal neurological care has also gained increased focus. This review summarizes current data on the timing and pattern of altered prenatal brain development in congenital heart disease, the potential mechanisms of these abnormalities, and the association with perioperative neurological complications.

Impact of extracardiac pathology on head growth in fetuses with congenital heart defect

OBJECTIVE

Neurodevelopmental delay is frequently encountered in children with a congenital heart defect (CHD). Fetuses with major CHD have a smaller head circumference (HC), irrespective of altered cerebral flow or brain oxygenation. This cohort study compared head growth in cases with isolated vs those with non-isolated CHD to evaluate the effect of additional pathology on head size in these fetuses.

METHOD

All CHD cases diagnosed prenatally in the period January 2002-July 2014 were selected from our regional registry, PRECOR. Cases of multiple pregnancy, and those affected by maternal diabetes, severe fetal structural brain anomalies or functional CHD were excluded. Subjects were divided into groups according to whether the CHD was isolated, and the non-isolated group was subdivided into three groups: cases with genetic anomaly, extracardiac malformation or placental pathology. In both isolated and non-isolated CHD groups, CHDs were also grouped according to their potential effect on aortic flow and oxygen saturation. Mean HC Z-scores at 20 weeks and increase or decrease (Δ) of HC Z-scores over the course of pregnancy were compared between isolated and non-isolated groups, using mixed linear regression models.

RESULTS

Included were 916 cases of CHD diagnosed prenatally, of which 378 (41.3%) were non-isolated (37 with placental pathology, 217 with genetic anomaly and 124 with extracardiac malformation). At 20 weeks, non-isolated cases had significantly lower HC Z-scores than did isolated cases (Z-score = -0.70 vs -0.03; P < 0.001) and head growth over the course of pregnancy showed a larger decrease in this group (Δ HC Z-score = -0.03 vs -0.01 per week; P = 0.01). Cases with placental pathology had the lowest HC Z-score at 20 weeks (Z-score = -1.29) and the largest decrease in head growth (Δ HC Z-score = -0.06 per week). In CHD subjects with a genetic diagnosis (Z-score = -0.73; Δ HC Z-score = -0.04 per week) and in those with an extracardiac malformation (Z-score = -0.49; Δ HC Z-score = -0.02 per week), HC Z-scores were also lower compared with those in subjects with isolated CHD. CHDs that result in low oxygenation or flow to the brain were present more frequently in isolated than in non-isolated cases.

CONCLUSIONS

Smaller HC in fetuses with CHD appears to be associated strongly with additional pathology. Placental pathology and genetic anomaly in particular seem to be important contributors to restricted head growth. This effect appears to be irrespective of altered hemodynamics caused by the CHD. Previously reported smaller HC in CHD should, in our opinion, be attributed to additional pathology. Neurodevelopment studies in infants with CHD should, therefore, always differentiate between isolated and non-isolated cases. © 2019 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Fetal cardiac intervention-Perspectives from a single center

Fetal cardiac intervention was first proposed in the early 1990s to impact cardiac development and survival of fetuses with fetal aortic stenosis and evolving hypoplastic left heart syndrome (HLHS). Although initial attempts of fetal aortic valvuloplasty were unsuccessful and carried a high rate of morbidity and mortality, our collaborative group at the Brigham and Women's Hospital and Boston Children's Hospital have reinvigorated the procedure using improvements in imaging, anesthesia, balloon catheters, and surgical techniques. Two decades of experience have now allowed us to document the safety of in utero intervention and to achieve a better understanding of the impact of midgestation intervention on developing HLHS. Research into underlying genetics, predictive biomarkers, and ways to incorporate stem cell technology will hopefully allow us to further refine the procedure to most benefit children with this historically lethal disease.

Neurodevelopmental outcomes of children with congenital heart disease: A review

Congenital heart defects are the most common birth anomaly affecting approximately 1% of births. With improved survival in this population, there is enhanced ability to assess long-term morbidities including neurodevelopment. There is a wide range of congenital heart defects, from those with minimal physiologic consequence that do not require medical or surgical intervention, to complex structural anomalies requiring highly specialized medical management and intricate surgical repair or palliation. The impact of congenital heart disease on neurodevelopment is multifactorial. Susceptibility for adverse neurodevelopment increases with advancing severity of the defect with initial risk factors originating during gestation. Complex structural heart anomalies may pre-dispose the fetus to abnormal circulatory patterns in utero that ultimately impact delivery of oxygen rich blood to the fetal brain. Thus, the brain of a neonate born with complex congenital heart disease may be particularly vulnerable from the outset. That vulnerability is compounded during the newborn period and through childhood, as this population endures a myriad of medical and surgical interventions. For each individual patient, these factors are likely cumulative and synergistic with progression from fetal life through childhood. This review discusses the spectrum of risk factors that may impact neurodevelopment in children with congenital heart disease, describes current recommendations and practices for neurodevelopmental follow-up of children with congenital heart disease and reviews important neurodevelopmental trends in this high risk population.

Evaluation and Management of the Child and Adult With Fontan Circulation: A Scientific Statement From the American Heart Association

It has been 50 years since Francis Fontan pioneered the operation that today bears his name. Initially designed for patients with tricuspid atresia, this procedure is now offered for a vast array of congenital cardiac lesions when a circulation with 2 ventricles cannot be achieved. As a result of technical advances and improvements in patient selection and perioperative management, survival has steadily increased, and it is estimated that patients operated on today may hope for a 30-year survival of >80%. Up to 70 000 patients may be alive worldwide today with Fontan circulation, and this population is expected to double in the next 20 years. In the absence of a subpulmonary ventricle, Fontan circulation is characterized by chronically elevated systemic venous pressures and decreased cardiac output. The addition of this acquired abnormal circulation to innate abnormalities associated with single-ventricle congenital heart disease exposes these patients to a variety of complications. Circulatory failure, ventricular dysfunction, atrioventricular valve regurgitation, arrhythmia, protein-losing enteropathy, and plastic bronchitis are potential complications of the Fontan circulation. Abnormalities in body composition, bone structure, and growth have been detected. Liver fibrosis and renal dysfunction are common and may progress over time. Cognitive, neuropsychological, and behavioral deficits are highly prevalent. As a testimony to the success of the current strategy of care, the proportion of adults with Fontan circulation is increasing. Healthcare providers are ill-prepared to tackle these challenges, as well as specific needs such as contraception and pregnancy in female patients. The role of therapies such as cardiovascular drugs to prevent and treat complications, heart transplantation, and mechanical circulatory support remains undetermined. There is a clear need for consensus on how best to follow up patients with Fontan circulation and to treat their complications. This American Heart Association statement summarizes the current state of knowledge on the Fontan circulation and its consequences. A proposed surveillance testing toolkit provides recommendations for a range of acceptable approaches to follow-up care for the patient with Fontan circulation. Gaps in knowledge and areas for future focus of investigation are highlighted, with the objective of laying the groundwork for creating a normal quality and duration of life for these unique individuals.

'Big issues' in neurodevelopment for children and adults with congenital heart disease

It is established that neurodevelopmental disability (NDD) is common in neonates undergoing complex surgery for congenital heart disease (CHD); however, the trajectory of disability over the lifetime of individuals with CHD is unknown. Several ‘big issues’ remain undetermined and further research is needed in order to optimise patient care and service delivery, to assess the efficacy of intervention strategies and to promote best outcomes in individuals of all ages with CHD. This review article discusses ‘gaps’ in our knowledge of NDD in CHD and proposes future directions.

Neurocognitive Difficulties Among Youth with POTS within an Intensive Pain Rehabilitation Program

OBJECTIVE

Adolescents and young adults (AYAs) with postural orthostatic tachycardia syndrome (POTS) commonly report cognitive difficulties, though there is limited information regarding the objective measurement of neurocognitive deficits in this population. This study described the rates of subjectively experienced and objectively measured neurocognitive difficulties and explored effects of medications on neurocognitive functioning among AYAs with POTS admitted to an intensive outpatient pain rehabilitation program.

METHODS

Participants in a pain rehabilitation program diagnosed with POTS (N = 96; ages 12-22) were included in the study. Medical characteristics, reported cognitive complaints, and neurocognitive assessment results were collected through retrospective medical record review. We calculated descriptive statistics and Pearson's χ2 or Fisher's exact tests, where appropriate.

RESULTS

While 96% of this sample reported subjective cognitive complaints, as a group, they performed in the Average range on standardized measures of intellectual functioning, attention, and memory. The majority did not demonstrate any normative (73%) or relative (54%) weaknesses in attention or memory. Those prescribed an antiepileptic (n = 19) were less likely to have visual-spatial memory weaknesses but more likely to have attention weaknesses.

CONCLUSIONS

Despite a high frequency of reported cognitive difficulties, most AYAs with POTS did not demonstrate neurocognitive impairment on standardized, one-on-one assessment. Suggestions for further study of biopsychosocial contributors to neurocognitive difficulties and for clinical use of neurocognitive assessments in this population were provided.

Fetuses with Isolated Congenital Heart Defects Show Normal Cerebral and Extracerebral Fluid Volume Growth: A 3D Sonographic Study in the Second and Third Trimester

OBJECTIVE

The aim of our study is to explore whether the cerebral growth is delayed in fetuses with congenital heart defects (CHD) in the second and early third trimester.

METHODS

A prospective cohort study was conducted in 77 CHD cases, with 75 healthy controls. 3D cerebral volume acquisition was performed sequentially. The volumes of the fetal hemicerebrum and extracerebral fluid were compared by linear regression analysis, and the Sylvian fissure was measured.

RESULTS

Between 19 and 32 weeks of gestation, 158 measurements in cases and 183 measurements in controls were performed (mean 2.2/subject). The volume growth of the hemicerebrum (R2 = 0.95 vs. 0.95; p = 0.9) and the extracerebral fluid (R2 = 0.84 vs. 0.82, p = 0.9) were similar. Fetuses with abnormal oxygen delivery to the brain have a slightly smaller brain at 20 weeks of gestation (p = 0.02), but this difference disappeared with advancing gestation. CHD cases demonstrated a slightly shallower Sylvian fissure (mean ratio 0.146 vs. 0.153; p = 0.004).

CONCLUSIONS

Our study shows no differences in cerebral growth, studied in an unselected cohort, with successive cases of isolated CHD. Even in the severest CHD cases, cerebral size is similar in the early third trimester. The cause and meaning of a shallower Sylvian fissure is unclear; possibly, it is a marker for delayed cerebral maturation or it might be an expression of decreasing amount of extracerebral fluid.

Abnormal fetal cerebral and vascular development in hypoplastic left heart syndrome

Objective

To assess the cerebral and vascular development in fetuses with hypoplastic left heart syndrome (HLHS).

Methods

Pregnant women carrying fetuses diagnosed with HLHS who decided to interrupt their pregnancies were included in our study. Aortic size and blood flow were assessed based from fetal echocardiography. Immunohistochemical staining was performed in brain sections obtained from pathology in fetuses with HLHS and control fetuses without heart disease.

Results

Twenty‐seven midgestation fetal HLHS were included (gestational age, 23.3 ± 3.4 weeks). Head circumference z scores were lower in HLHS fetuses. Middle cerebral artery pulsatility index, a measure of cerebrovascular resistance, was inversely correlated with the ascending aortic z score (P < 0.05). Fetuses with HLHS had lower capillary density in the germinal matrix and their capillaries were larger compared with control fetuses with (P < 0.05). The expression of neuronal differentiation marker, FGFR1, and oligodendrocyte precursor, O4, were lower in HLHS brains compared with controls (P < 0.05).

Conclusion

Our study identified abnormalities of vascular flow and structural brain abnormalities in fetal HLHS associated with impaired neuronal and oligodendrocyte differentiation, as well as cerebral growth impairment, early in gestation. These findings may be related in part to early vascular abnormalities.

What's already known about this topic?

Structural brain abnormalities and abnormalities in neurodevelopment have been reported in HLHS.

What does this study add?

Our study describes abnormal vascular development that may account for abnormal neuronal and white matter differentiation in the developing fetus with HLHS.

Brain angiogenic gene expression in fetuses with congenital heart disease

OBJECTIVE

To assess potential differences in the expression of antiangiogenic and angiogenic factors and of genes associated with chronic hypoxia in cerebral tissue of euploid fetuses with congenital heart disease (CHD) vs those without.

METHODS

Cerebral tissue was obtained from 15 fetuses with CHD and 12 control fetuses that had undergone termination of pregnancy. Expression profiles of the antiangiogenic factor soluble fms-like tyrosine kinase-1 (sFlt-1), the angiogenic vascular endothelial growth factor-A (VEGF-A) and placental growth factor (PlGF), and of genes associated with chronic hypoxia were determined by real-time polymerase chain reaction in tissue from the frontal cortex and the basal ganglia of the fetuses.

RESULTS

Expression of sFlt-1 was 48% higher in the frontal cortex (P = 0.0431) and 72% higher in the basal ganglia (P = 0.0369) of CHD fetuses compared with controls. The expression of VEGF-A was 60% higher (P = 0.0432) and that of hypoxia-inducible factor 2-alpha was 98% higher (P = 0.0456) in the basal ganglia of CHD fetuses compared with controls. No significant differences were observed between the two groups in the expression of PlGF and hypoxia-inducible factor 1-alpha.

CONCLUSION

An overall dysregulation of angiogenesis with a net balance towards an antiangiogenic environment was observed in the cerebral tissue of fetuses with CHD, suggesting that these fetuses may have an intrinsic angiogenic impairment that could contribute to impaired brain perfusion and abnormal neurological development later in life. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Neurocognitive profiles in adolescents and young adults with congenital heart disease

INTRODUCTION AND OBJECTIVES

The objectives of this study were to assess the neuropsychological performance (NP) of adolescents and young adults with congenital heart disease (CHD), comparing them with a group of healthy controls, to determine whether there are different neurocognitive phenotypes in CHD, and to identify their relation to sociodemographic, neonatal, clinical and psychological adjustment variables.

METHODS

A total of 217 CHD patients (116 male, aged 15.73±2.68 years) and 80 controls (35 male, age 16.76±2.22 years) underwent an extensive neuropsychological assessment and analysis of psychological adjustment.

RESULTS

CHD patients had significantly poorer NP than healthy controls in all neurocognitive domains. Three different phenotypes of NP in CHD patients were identified: non-impaired (NI), moderately impaired (MI) and globally impaired (GI). They differed in all dimensions of NP. The GI cluster showed fewer years of schooling (p=0.025) and lower neonatal indicators such as head circumference (p=0.019), 1-min Apgar score (p=0.006), birth weight (p=0.05) and length (p=0.034) than the NI cluster. In the MI and GI clusters, there were more cyanotic forms of disease, including tetralogy of Fallot and transposition of the great arteries. The GI cluster presented more difficulties with psychological adjustment, including social (p=0.038), attention (p=0.001) and aggressive (p=0.003) problems.

CONCLUSIONS

CHD patients have poorer NP than controls. NP in the CHD group can be classified in three clusters that reflect different levels of neuropsychological functioning, which is sensitive to social, neonatal and psychological adjustment variables.

Effect of fetal hemodynamics on growth in fetuses with single ventricle or transposition of the great arteries

OBJECTIVES

As birth weight is a critical predictor of outcome in neonates with congenital heart defect (CHD), the common problem of poor fetal growth in this population is clinically important. However, it is not well understood and the impact of fetal hemodynamics on fetal growth and birth weight in those with CHD has not been assessed. In this study, we sought to evaluate the association between combined cardiac output (CCO) and fetal middle cerebral artery (MCA) and umbilical artery (UA) pulsatility indices (PIs) and fetal growth in different subgroups of CHD, and to study the effects of fetal hemodynamics on late gestational weight gain. We hypothesized that fetuses with CHD will have lower CCO and be smaller at birth.

METHODS

This was a retrospective review of fetal echocardiograms from 67 fetuses diagnosed with hypoplastic left heart syndrome (HLHS, n = 30), non-HLHS single ventricle (SV) (n = 20) or dextrotransposition of the great arteries (d-TGA, n = 17), compared with normal controls (n = 42). CCO was calculated using valvar area, velocity-time integral and heart rate and indexed to estimated fetal weight. MCA- and UA-PI were calculated using systolic, diastolic and mean velocities. Fetal biometry was recorded. Regression models were used to study trends in CCO, MCA- and UA-PI and fetal biometry over gestational age. To evaluate fetal weight gain in late gestation, Z-scores of estimated fetal weight at 30 weeks and birth weight were compared. Regression analysis was used to determine the associations of CCO, indexed CCO and MCA- and UA-PI at 30 weeks with birth weight, length and head circumference Z-scores, in addition to weight gain late in gestation. The gestational age of 30 weeks was chosen based on previous studies that found evidence of poor weight gain in fetuses with CHD in late gestation, starting at around that time.

RESULTS

CCO increased with gestation in all four groups but the rate was slower in fetuses with HLHS and in those with SV. MCA-PI was lower in fetuses with HLHS compared with in those with non-HLHS-SV throughout gestation, suggesting different cerebral blood distribution. At the end of gestation, rate of fetal weight gain slowed in those with HLHS and in those with SV (similar to CCO curves), and head circumference growth rate slowed in all groups but controls. CCO, indexed CCO and MCA- and UA-PI did not correlate with any of the birth measurements or with weight gain late in gestation in fetuses with CHD.

CONCLUSIONS

We found no associations of CCO or MCA- and UA-PI with late gestational weight gain or biometry at birth in fetuses with CHD. This does not support fetal hemodynamics as the primary driver of suboptimal fetal growth in fetuses with SV. Future research could further explain genetic and placental abnormalities that may affect fetal growth in those with CHD. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Cerebrovascular response to maternal hyperoxygenation in fetuses with hypoplastic left heart syndrome depends on gestational age and baseline cerebrovascular resistance

OBJECTIVES

Compared with normal fetuses, fetuses with hypoplastic left heart syndrome (HLHS) have smaller brain volumes and are at higher risk of brain injury, possibly due to diminished cerebral blood flow and oxygen content. By increasing cerebral oxygen delivery, maternal hyperoxygenation (MH) might improve brain development and reduce the risk of brain injury in these fetuses. This study investigated whether gestational age and baseline cerebrovascular resistance affect the response to MH in fetuses with HLHS.

METHODS

The study population comprised 43 fetuses with HLHS or HLHS variant referred for fetal echocardiography between January 2004 and September 2008. Middle cerebral artery (MCA) pulsatility index (PI), a surrogate measure of cerebrovascular resistance, was assessed between 20 and 41 weeks' gestation at baseline in room air (RA) and after 10 min of MH. Z-scores of MCA-PI were generated. A mixed-effects model was used to determine whether change in MCA-PI depends upon gestational age and baseline MCA-PI.

RESULTS

In RA and following MH, MCA-PI demonstrated a curvilinear relationship with gestational age in fetuses with HLHS, peaking at around 28 weeks and then falling more steeply near term. MCA-PI Z-score declined in a linear manner, such that it was 1.4 SD below that in normal fetuses at 38 weeks. Increase in MCA-PI Z-score after MH was first seen at ≥ 28 weeks. A baseline MCA-PI Z-score ≤ -0.96 was predictive of an increase in cerebrovascular resistance in response to MH.

CONCLUSION

In fetuses with HLHS, MCA-PI first increases in response to MH at ≥ 28 weeks' gestation. A baseline MCA-PI Z-score ≤ -0.96 predicts an increase in cerebrovascular resistance in response to MH. These results may have implications for clinical trials utilizing MH as a neuroprotective agent. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Altered White Matter Microstructure Correlates with IQ and Processing Speed in Children and Adolescents Post-Fontan

OBJECTIVE

To compare white matter microstructure in children and adolescents with single ventricle who underwent the Fontan procedure with healthy controls, and to explore the association of white matter injury with cognitive performance as well as patient and medical factors.

STUDY DESIGN

Fontan (n = 102) and control subjects (n = 47) underwent diffusion tensor imaging (DTI) at ages 10-19 years. Mean DTI measures (fractional anisotropy, radial diffusivity, axial diffusivity, and mean diffusivity) were calculated for 33 fiber tracts from standard white matter atlases. Voxel-wise group differences in DTI measures were assessed using Tract-Based Spatial Statistics. Associations of regional fractional anisotropy with IQ and processing speed as well as medical characteristics were examined.

RESULTS

Subjects with Fontan, compared with controls, had reduced bilateral regional and voxel-wise fractional anisotropy in multiple white matter tracts along with increased regional radial diffusivity in several overlapping tracts; regional mean diffusivity differed in 2 tracts. The groups did not differ in voxel-wise radial diffusivity or mean diffusivity. Among subjects with Fontan, fractional anisotropy in many tracts correlated positively with Full-Scale Intelligence Quotient and processing speed, although similar findings were absent in controls. Lower mean fractional anisotropy in various tracts was associated with more complications in the first operation, a greater number of total operations, and history of neurologic event.

CONCLUSIONS

Children and adolescents who have undergone the Fontan procedure have widespread abnormalities in white matter microstructure. Furthermore, white matter microstructure in several tracts is associated with cognitive performance and operative and medical history characteristics.

Hemodynamic adaptation to suboptimal fetal growth in patients with single ventricle physiology

BACKGROUND

In fetuses with structurally normal heart and suboptimal fetal growth (SFG), umbilical artery vascular resistance increases as measured by umbilical artery pulsatility index (UA-PI). The objective of this study is to compare hemodynamic responses to SFG in fetuses with single ventricle (SV) and controls with structurally normal heart.

METHODS

Fetal echocardiograms around 30 weeks of gestation were reviewed. UA-PI and middle cerebral artery pulsatility index (MCA-PI) were calculated. SFG was defined as a birth weight below 25th percentile for gestational age.

RESULTS

Studies from 92 fetuses were reviewed-SV (n = 50) and controls (n = 42). The prevalence of SFG was higher in SV compared to controls (46% vs 21%, P = .02). In patients with normal heart and SFG, UAPI was significantly higher than normal controls (P = .003) suggesting increased placental vascular resistance. In SV with SFG there was no difference in UAPI compared to SV without SFG. There was no difference in MCA-PI between the groups.

CONCLUSIONS

The hemodynamic response to SFG in SV varies from fetuses with structurally normal heart. The mechanism of SFG and the placental pathology may be distinct in SV.

Volumetric Brain MRI Study in Fetuses with Congenital Heart Disease

BACKGROUND AND PURPOSE

It is well-established that a high prevalence of infants with congenital heart defects surviving to childhood have neurodevelopmental abnormalities. The etiology is not clear. In this study, we aimed to find prenatal neuroanatomic changes in fetuses with congenital heart disease to better understand the pathophysiology behind these sequelae.

MATERIALS AND METHODS

A retrospective study of 46 fetal brain MR imaging scans was performed at a tertiary medical center during a 4-year period. Clinical data were collected from electronic medical charts. Volumes of the supratentorial brain, right hemisphere, left hemisphere, and cerebellum were measured using a semiautomated method and were compared with the normal growth percentiles.

RESULTS

We found that cerebellar volume and the cerebellar-supratentorial volume ratio were significantly lower among fetuses with congenital heart disease. Supratentorial and hemisphere volumes showed no difference between groups. This difference was not observed in fetuses with septation defects.

CONCLUSIONS

Fetuses with congenital heart disease have smaller cerebellar volumes than healthy fetuses. Additional research is needed to assess this finding as a radiologic marker for long-term outcome.

Increased Pituitary Volumes in Children after Fontan Operation: Congestion in the Other Portal Circulation

We performed brain magnetic resonance imaging in 40 patients after the Fontan procedure and 40 control subjects. Pituitary volumes in patients after Fontan were significantly larger than those in the control subjects (472 [425-527] vs 257 [182-311]; P < .0001), and were significantly related to central venous pressure.

Reduction of brain volumes after neonatal cardiopulmonary bypass surgery in single-ventricle congenital heart disease before Fontan completion

BackgroundLittle is known about the relationship between brain volumes and neurodevelopmental outcome at 2 years of age in children with single-ventricle congenital heart disease (CHD). We hypothesized that reduced brain volumes may be associated with adverse neurodevelopmental outcome.MethodsVolumetric segmentation of cerebral magnetic resonance imaging (MRI) scans was carried out in 44 patients without genetic comorbidities and in 8 controls. Neurodevelopmental outcome was assessed with the Bayley-III scales.ResultsGray matter (GM), deep GM, white matter (WM), and cerebrospinal fluid (CSF) volumes were 611±59, 43±4.5, 277±30, and 16.4 ml, respectively (interquartile range (IQR) 13.1, 23.3 ml). Children undergoing neonatal cardiopulmonary bypass surgery showed smaller deep GM (P=0.005) and WM (P=0.021) volumes. Brain volumes were smaller in patients compared with controls (GM: P=0.017, deep GM: P=0.012, and WM: P=0.015), whereas CSF volumes were greater (P=0.014). Of all intracranial volumes, only CSF volume was associated with neurodevelopmental outcome, accounting for 21% (P=0.011) of variability in the cognitive composite score when combined with common risk factors in a multivariable analysis.ConclusionIncreased CSF volume represents a significant risk factor for neurodevelopmental impairment in children with single-ventricle CHD. Later assessments are warranted to determine the prognostic role of intracranial volumes for long-term outcome.

Congenital Heart Disease and Neurodevelopment: Clinical Manifestations, Genetics, Mechanisms, and Implications

Children with congenital heart disease (CHD) are at increased risk of neurodevelopmental disorders (NDDs) and psychiatric conditions. These include cognitive, adaptive, motor, speech, behavioural, and executive functioning deficits, as well as autism spectrum disorder and psychiatric conditions. Structural and functional neuroimaging have demonstrated brain abnormalities in young children with CHD before undergoing surgical repair, likely as a result of an in utero developmental insult. Surgical factors do not seem to play a significant role in neurodevelopmental outcomes. Specific genetic abnormalities, particularly copy number variants, have been increasingly implicated in both CHD and NDDs. Variations in genes involved in apolipoprotein E (APOE) production, the Wnt signalling pathway, and histone modification, as well as in the 1q21.1, 16p13.1-11, and 8p23.1 genetic loci, have been associated with CHD and NDDs and are important targets for future research. Understanding these associations is important for risk stratification, disease classification, improved screening, and pharmacologic management of individuals with CHD.

In Utero Evidence of Impaired Somatic Growth in Hypoplastic Left Heart Syndrome

We hypothesized that fetuses with hypoplastic left heart syndrome (HLHS) have impaired growth compared to expected growth for gestational age. This is a retrospective cohort study including singleton fetuses with isolated HLHS identified from a single, referral center's ultrasound database. To account for variable timing of ultrasounds, z-scores for gestational age were assigned for each biometric parameter. We identified 169 fetuses, of which 96 had more than one ultrasound. The median number of ultrasound evaluations per fetus was 2 (range 1-5). The mean gestational age at time of last ultrasound was 33.7 ± 4.3 weeks with a range of 20.4-39.6 weeks. While fetal growth restriction (11%) and microcephaly (3%) were relatively rare, mean z-scores at the time of last ultrasound for estimated fetal weight (mean difference z-score -0.20, p = 0.04) and head circumference (-0.28, p = 0.02) were lower than at the time of the initial ultrasound. Impaired somatic growth, defined as a decrement in z-score of 0.5 or more over time, was common (32%). There is a deceleration in somatic and head growth in fetuses with hypoplastic left heart syndrome that can be identified by routine ultrasound evaluation.

Congenital Heart Defects and Measures of Prenatal Brain Growth: A Systematic Review

BACKGROUND

We summarize the evidence for an association between congenital heart defects and prenatal brain growth through a systematic literature review. Congenital heart defects are among the most common malformations, affecting approximately six per 1000 live births. The association between congenital heart defects and long-term neurodevelopmental disorders is well established. Increasing evidence suggests an association between impaired prenatal brain growth and neurodevelopmental disorders in children with congenital heart defects.

METHODS

Systematic literature searches were performed in PubMed and EMBASE. We included original studies comparing fetuses or newborns with congenital heart defects to reference fetuses or newborns with respect to brain biometrics, including biparietal diameter, brain volume, and head circumference at birth. The study characteristics and the results were extracted and presented in tables. No meta-analysis was undertaken.

RESULTS

Twenty-eight studies were included. All except two studies found an association between congenital heart defects and measures of reduced prenatal brain growth. The strongest evidence concerned hypoplastic left heart syndrome, tetralogy of Fallot, and transposition of the great arteries.

CONCLUSIONS

The literature suggests an association between congenital heart defects and measures of impaired prenatal brain growth. However, most studies were small and failed to include important potential confounding factors and to address other sources of potential bias as well. Future large-scale studies that address potential confounders are warranted.

Hypoplastic Left Heart Syndrome is not Associated with Worse Clinical or Neurodevelopmental Outcomes Than Other Cardiac Pathologies After the Norwood-Sano Operation

There is evidence to suggest that patients undergoing a Norwood for non-HLHS anatomy may have lower mortality than classic HLHS, but differences in neurodevelopmental outcome have not been assessed. Our objective was to compare survival and neurodevelopmental outcome during the same surgical era in a large, well-described cohort. All subjects who underwent a Norwood-Sano operation between 2005 and 2014 were included. Follow-up clinical, neurological, and developmental data were obtained from the Western Canadian Complex Pediatric Therapies Follow-up Program database. Developmental outcomes were assessed at 2 years of age using the Bayley Scales of Infant and Toddler Development (Bayley-III). Survival was assessed using Kaplan-Meier analysis. Baseline characteristics, survival, and neurodevelopmental outcomes were compared between those with HLHS and those with non-HLHS anatomy (non-HLHS). The study comprised 126 infants (75 male), 87 of whom had HLHS. Five-year survival was the same for subjects with HLHS and those with non-HLHS (HLHS 71.8%, non-HLHS 76.9%; p = 0.592). Ninety-three patients underwent neurodevelopmental assessment including Bayley-III scores. The overall mean cognitive composite score was 91.5 (SD 14.6), language score was 86.6 (SD 16.7) and overall mean motor composite score was 85.8 (SD 14.5); being lower than the American normative population mean score of 100 (SD 15) for each (p-value for each comparison, <0.0001). None of the cognitive, language, or motor scores differed between those with HLHS and non-HLHS (all p > 0.05). In the generalized linear models, dominant right ventricle anatomy (present in 117 (93%) of patients) was predictive of lower language and motor scores. Comparative analysis of the HLHS and non-HLHS groups undergoing single ventricle palliation including a Norwood-Sano, during the same era, showed comparable 2-year survival and neurodevelopmental outcomes.

Reduced cortical volume and thickness and their relationship to medical and operative features in post-Fontan children and adolescents

BACKGROUND

We compared brain cortical and subcortical gray matter volumes and cortical thickness between post-Fontan patients and healthy controls, and examined brain anatomical associations with operative and medical history characteristics.

METHODS

Post-Fontan (n = 128 volumes; n = 115 thickness) and control subjects (n = 48 volumes; n = 45 thickness) underwent brain MRI at ages 10-19 y. Subcortical and cortical volumes and cortical thicknesses were measured for intergroup comparison. Associations between brain measures and clinical measures were assessed in the Fontan group.

RESULTS

Widespread, significant reduction in brain volumes and thicknesses existed in the Fontan group compared to controls, spanning all brain lobes and subcortical gray matter. Fontan subjects treated with vs. without the Norwood procedure had smaller volumes in several terminal clusters, but did not differ in cortical thickness. Older age at first operation and increasing numbers of cardiac catheterizations, operative complications, and catheterization complications were associated with lower regional volumes and thicknesses. Increasing numbers of operative complications and cardiac catheterizations were associated with smaller regional volumes in the Norwood group.

CONCLUSION

The post-Fontan adolescent brain differs from the normal control brain. Some of these differences are associated with potentially modifiable clinical variables, suggesting that interventions might improve long-term neurocognitive outcome.

Neurodevelopmental Outcome in Children after Fetal Cardiac Intervention for Aortic Stenosis with Evolving Hypoplastic Left Heart Syndrome

OBJECTIVE

To characterize neurodevelopmental outcomes after fetal aortic valvuloplasty for evolving hypoplastic left heart syndrome and determine the risk factors for adverse neurodevelopment.

STUDY DESIGN

Questionnaires were mailed to families of children who underwent fetal aortic valvuloplasty from 2000 to 2012, and medical records were reviewed retrospectively. The primary outcome was the General Adaptive Composite score of the Adaptive Behavior Assessment System Questionnaire-Second Edition. Other questionnaires included the Behavior Assessment System for Children, Behavior Rating Inventory of Executive Function, Ages and Stages, and Pediatric Quality of Life Inventory.

RESULTS

Among 69 eligible subjects, 52 (75%) completed questionnaires at median age of 5.5 (range 1.3-12) years; 30 (58%) had biventricular status circulation. The General Adaptive Composite mean score (92 ± 17) was lower than population norms (P < .001) and similar to published reports in patients with hypoplastic left heart syndrome without fetal intervention; scores in the single ventricular versus biventricular group were 97 ± 19 vs 89 ± 14, respectively (P = .10). On multivariable analysis, independent predictors of a lower General Adaptive Composite score were total hospital duration of stay in the first year of life (P = .001) and, when forced into the model, biventricular status (P = .02). For all other neurodevelopmental questionnaires (Behavior Assessment System for Children, Behavior Rating Inventory of Executive Function, Ages and Stages, Pediatric Quality of Life Inventory), most subscale scores for patients with biventricular and single ventricular status were similar.

CONCLUSION

Children who underwent fetal aortic valvuloplasty have neurodevelopmental delay, similar to patients with hypoplastic left heart syndrome without fetal intervention. Achievement of biventricular circulation was not associated with better outcomes. We infer that innate patient factors and morbidity during infancy have the greatest effect on neurodevelopmental outcomes.

Neurodevelopmental Abnormalities and Congenital Heart Disease: Insights Into Altered Brain Maturation

In the past 2 decades, it has become evident that individuals born with congenital heart disease (CHD) are at risk of developing life-long neurological deficits. Multifactorial risk factors contributing to neurodevelopmental abnormalities associated with CHD have been identified; however, the underlying causes remain largely unknown, and efforts to address this issue have only recently begun. There has been a dramatic shift in focus from newly acquired brain injuries associated with corrective and palliative heart surgery to antenatal and preoperative factors governing altered brain maturation in CHD. In this review, we describe key time windows of development during which the immature brain is vulnerable to injury. Special emphasis is placed on the dynamic nature of cellular events and how CHD may adversely impact the cellular units and networks necessary for proper cognitive and motor function. In addition, we describe current gaps in knowledge and offer perspectives about what can be done to improve our understanding of neurological deficits in CHD. Ultimately, a multidisciplinary approach will be essential to prevent or improve adverse neurodevelopmental outcomes in individuals surviving CHD.

Longitudinal changes in fetal biometry and cerebroplacental hemodynamics in fetuses with congenital heart disease

OBJECTIVES

To determine the longitudinal behavior of fetal biometric measures and cerebroplacental hemodynamics throughout gestation in fetuses with congenital heart disease (CHD).

METHODS

Fetal biometry and Doppler hemodynamics (uterine artery (UtA), umbilical artery (UA) and fetal middle cerebral artery (MCA)) were measured serially in a cohort of consecutive fetuses diagnosed with CHD. Evaluations were made at various time points, from diagnosis (20-25 weeks) to delivery, with at least two measurements per fetus that were at least 2 weeks apart. Fetuses were classified into three groups according to the pattern of blood supply to the brain (placental vs systemic) that would be expected on the basis of the type of CHD. All parameters were transformed into Z-scores. A linear mixed model to analyze repeated measurements was constructed for each parameter to assess its behavior throughout gestation.

RESULTS

Four hundred and forty-four ultrasound examinations were performed in 119 CHD fetuses, with a median of two measurements per fetus. The fetuses presented a small head at diagnosis (biparietal diameter (BPD) Z-score, -1.32 ± 0.99; head circumference (HC) Z-score, -0.79 ± 1.02), which remained small throughout gestation. UtA and UA pulsatility indices (PI) showed a significant increase towards the end of pregnancy, whereas no significant changes were observed in MCA-PI or cerebroplacental ratio (CPR) with gestational age. Both MCA and CPR presented significant differences in longitudinal behavior between CHD groups, while BPD and HC did not.

CONCLUSIONS

CHD fetuses have a relatively small head from the second trimester of pregnancy, regardless of the type of CHD anomaly, and increasing resistance in the UtA and UA as pregnancy progresses, suggestive of increasing degree of placental impairment. Our findings indicate the early onset of mechanisms that could lead to poorer neurodevelopment later in life. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

The neurodevelopmental implications of hypoplastic left heart syndrome in the fetus

As survival after cardiac surgery continues to improve, an increasing number of patients with hypoplastic left heart syndrome are reaching school age and beyond, with growing recognition of the wide range of neurodevelopmental challenges many survivors face. Improvements in fetal detection rates, coupled with advances in fetal ultrasound and MRI imaging, are contributing to a growing body of evidence that abnormal brain architecture is in fact present before birth in hypoplastic left heart syndrome patients, rather than being solely attributable to postnatal factors. We present an overview of the contemporary data on neurodevelopmental outcomes in hypoplastic left heart syndrome, focussing on imaging techniques that are providing greater insight into the nature of disruptions to the fetal circulation, alterations in cerebral blood flow and substrate delivery, disordered brain development, and an increased potential for neurological injury. These susceptibilities are present before any intervention, and are almost certainly substantial contributors to adverse neurodevelopmental outcomes in later childhood. The task now is to determine which subgroups of patients with hypoplastic left heart syndrome are at particular risk of poor neurodevelopmental outcomes and how that risk might be modified. This will allow for more comprehensive counselling for carers, better-informed decision making before birth, and earlier, more tailored provision of neuroprotective strategies and developmental support in the postnatal period.

Longitudinal analysis of head and somatic growth in fetuses with congenital heart defects

PURPOSE

Fetal head and somatic growth dynamics differs in fetuses with congenital heart defects (CHD). We longitudinally characterized fetal head and somatic growth in relation to the type of CHD.

METHODS

Four hundred eleven exams from isolated CHD were compared with 1,219 controls. Head and somatic growth was assessed using head circumference (HC), brain volume (BrV = 1/6 × π × (HC/π)3)/2), fetal cephalization index (FCI = BrV/[estimated fetal weight]), and growth percentile. Umbilical and middle cerebral artery Doppler indices were obtained. CHD were grouped as: (1) d-transposition of great arteries (n = 11); (2) left ventricular outflow tract obstruction with retrograde isthmic flow (n = 18); (3) left ventricular outflow tract obstruction with antegrade isthmic flow (n = 16); (4) pulmonary outflow tract obstructions (n = 22).

RESULTS

The smallest head size was seen in group 1. Growth asymmetry was diagnosed in group 2. Brain sparing was seen in groups 2 and 4 (p < 0.0001). HC and BrV percentiles decreased with advancing gestational age (p < 0.001) in group 2, and a significant drop was observed around 28 weeks.

CONCLUSIONS

d-Transposition of great arteries and left-sided CHD leading to isthmic blood flow reversal are associated with delayed head growth. Prenatal evaluation of central hemodynamics in CHD may be contributive for predicting neurodevelopmental risks in CHD and help directing prenatal interventions. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:96-104, 2017.

Glial fibrillary acidic protein as a biomarker for brain injury in neonatal CHD

Neonates with critical CHD have evidence, by imaging, of preoperative brain injury, although the timing is unknown. We used circulating postnatal serum glial fibrillary acidic protein as a measure of acute perinatal brain injury in neonates with CHD. Glial fibrillary acidic protein was measured on admission and daily for the first 4 days of life in case and control groups; we included two control groups in this study - non-brain-injured newborns and brain-injured newborns. Comparisons were performed using the Kruskal-Wallis test with Dunn's multiple comparisons, Student's t-test, and χ2 test of independence where appropriate. In aggregate, there were no significant differences in overall glial fibrillary acidic protein levels between CHD patients (n=56) and negative controls (n=23) at any time point. By day 4 of life, 7/56 (12.5%) CHD versus 0/23 (0%) normal controls had detectable glial fibrillary acidic protein levels. Although not statistically significant, the 5/10 (50%) left heart obstruction group versus 1/17 (6%) conoventricular, 0/13 (0%) right heart, and 1/6 (17%) septal defect patients trended towards elevated levels of glial fibrillary acidic protein at day 4 of life. Overall, glial fibrillary acidic protein reflected no evidence for significant peripartum brain injury in neonates with CHD, but there was a trend for elevation by postnatal day 4 in neonates with left heart obstruction. This pilot study suggests that methods such as monitoring glial fibrillary acidic protein levels may provide new tools to optimise preoperative care and neuroprotection in high-risk neonates with specific types of CHD.

Head growth in fetuses with isolated congenital heart defects: lack of influence of aortic arch flow and ascending aorta oxygen saturation

OBJECTIVES

Congenital heart defects (CHDs) are reported to be associated with a smaller fetal head circumference (HC) and neurodevelopmental delay. Recent studies suggest that altered intrauterine brain hemodynamics may explain these findings. Our objectives were to evaluate the pattern of head growth in a large cohort of fetuses with various types of CHD, analyze these patterns according to the type of CHD and estimate the effect of cerebral hemodynamics with advancing gestation in the second and third trimesters.

METHODS

Singleton fetuses with an isolated CHD were selected from three fetal medicine units (n = 436). Cases with placental insufficiency or genetic syndromes were excluded. CHD types were clustered according to the flow and oxygen saturation in the aorta. Z-scores of biometric data were constructed using growth charts of a normal population. HC at different gestational ages was evaluated and univariate and multivariate mixed regression analyses were performed to examine the patterns of prenatal HC growth.

RESULTS

Fetuses with severe and less severe types of CHD demonstrated statistically significant HC growth restriction with increasing gestational age (slope of -0.017/day); however, there was no statistically significant effect of fetal hemodynamics on HC growth. Fetuses with CHD but normal brain oxygenation and normal aortic flow showed a significant decrease in HC growth (slope of -0.024/day). Only fetuses with isolated tetralogy of Fallot demonstrated a smaller HC z-score at 20 weeks of gestation (-0.67 (95% CI, -1.16 to -0.18)).

CONCLUSIONS

Despite the decline in head growth in fetuses with a prenatally detected isolated CHD, HC values were within the normal range, raising the question of its clinical significance. Furthermore, in contrast to other studies, this large cohort did not establish a significant correlation between aortic flow or oxygen saturation and HC growth. Factors other than altered fetal cerebral hemodynamics may contribute to HC growth restriction with increasing gestational age, such as (epi)genetic or placental factors. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.