Hypoplastic left heart syndrome is associated with structural and vascular placental abnormalities and leptin dysregulation

Is there an increased risk of genetic abnormalities in fetuses with congenital heart disease in the setting of growth restriction?

OBJECTIVE

To determine if the presence of fetal growth restriction (FGR) is associated with an increased risk of genetic abnormalities in the setting of congenital heart disease (CHD).

METHODS

This was a retrospective cohort study involving pregnancies that met the following criteria: (i) prenatal diagnosis of CHD, (ii) singleton live-birth, and (iii) genetic testing was performed either pre- or postnatally. Genetic results were reviewed by a clinical geneticist for updated variant classification. Fetal growth was stratified as appropriate for gestational age (AGA) or FGR.

RESULTS

Of the total of 445 fetuses that met the study criteria, 325 (73.0%) were AGA and 120 (27.0%) were FGR. Genetic abnormalities were detected in 131 (29.4%) pregnancies. There was a higher rate of genetic abnormalities (36.7% vs. 26.8%, p = 0.04), which was driven by aneuploidies (20.8% vs. 8.9%, p = 0.0006) in the FGR population. Early onset growth restriction was associated with a higher rate of genetic abnormalities (44.5% vs. 25.9%, p = 0.03). The rate of genetic abnormalities was significantly higher in the shunt category as compared to remainder of the cardiac anomalies (62.5% in shunt lesions vs. 24.7%, p < 0.00001). The rates of FGR (40.9% vs. 21.4%, p < 0.0001) and genetic abnormalities (52% vs. 20.4%, p < 0.0001) were significantly higher in the presence of extra-cardiac anomalies (ECA).

CONCLUSION

The presence of FGR in fetal CHD population was associated with underlying genetic abnormalities, specifically aneuploidies. Patients should be appropriately counseled regarding the higher likelihood of a genetic condition in the presence of FGR, early onset FGR, shunt lesions and ECA.

Interdependence of placenta and fetal cardiac development

The placenta and fetal heart undergo development concurrently during early pregnancy, and, while human studies have reported associations between placental abnormalities and congenital heart disease (CHD), the nature of this relationship remains incompletely understood. Evidence from animal studies suggests a plausible cause and effect connection between placental abnormalities and fetal CHD. Biomechanical models demonstrate the influence of mechanical forces on cardiac development, whereas genetic models highlight the role of confined placental mutations that can cause some forms of CHD. Similar definitive studies in humans are lacking; however, placental pathologies such as maternal and fetal vascular malperfusion and chronic deciduitis are frequently observed in pregnancies complicated by CHD. Moreover, maternal conditions such as diabetes and pre-eclampsia, which affect placental function, are associated with increased risk of CHD in offspring. Bridging the gap between animal models and human studies is crucial to understanding how placental abnormalities may contribute to human fetal CHD. The next steps will require new methodologies and multidisciplinary approaches combining innovative imaging modalities, comprehensive genomic testing, and histopathology. These studies may eventually lead to preventative strategies for some forms of CHD by targeting placental influences on fetal heart development.

Placental Pathology Contributes to Impaired Volumetric Brain Development in Neonates With Congenital Heart Disease

BACKGROUND

Neonates with congenital heart disease are at risk for impaired brain development in utero, predisposing children to postnatal brain injury and adverse long-term neurodevelopmental outcomes. Given the vital role of the placenta in fetal growth, we assessed the incidence of placental pathology in fetal congenital heart disease and explored its association with total and regional brain volumes, gyrification, and brain injury after birth.

METHODS AND RESULTS

Placentas from 96 term singleton pregnancies with severe fetal congenital heart disease were prospectively analyzed for macroscopic and microscopic pathology. We applied a placental pathology severity score to relate placental abnormalities to neurological outcome. Postnatal, presurgical magnetic resonance imaging was used to analyze brain volumes, gyrification, and brain injuries. Placental analyses revealed the following abnormalities: maternal vascular malperfusion lesions in 46%, nucleated red blood cells in 37%, chronic inflammatory lesions in 35%, delayed maturation in 30%, and placental weight below the 10th percentile in 28%. Severity of placental pathology was negatively correlated with cortical gray matter, deep gray matter, brainstem, cerebellar, and total brain volumes (r=-0.25 to -0.31, all P<0.05). When correcting for postmenstrual age at magnetic resonance imaging in linear regression, this association remained significant for cortical gray matter, cerebellar, and total brain volume (adjusted R2=0.25-0.47, all P<0.05).

CONCLUSIONS

Placental pathology occurs frequently in neonates with severe congenital heart disease and may contribute to impaired brain development, indicated by the association between placental pathology severity and reductions in postnatal cortical, cerebellar, and total brain volumes.

PIBF1 regulates trophoblast syncytialization and promotes cardiovascular development

Proper placental development in early pregnancy ensures a positive outcome later on. The developmental relationship between the placenta and embryonic organs, such as the heart, is crucial for a normal pregnancy. However, the mechanism through which the placenta influences the development of embryonic organs remains unclear. Trophoblasts fuse to form multinucleated syncytiotrophoblasts (SynT), which primarily make up the placental materno-fetal interface. We discovered that endogenous progesterone immunomodulatory binding factor 1 (PIBF1) is vital for trophoblast differentiation and fusion into SynT in humans and mice. PIBF1 facilitates communication between SynT and adjacent vascular cells, promoting vascular network development in the primary placenta. This process affected the early development of the embryonic cardiovascular system in mice. Moreover, in vitro experiments showed that PIBF1 promotes the development of cardiovascular characteristics in heart organoids. Our findings show how SynTs organize the barrier and imply their possible roles in supporting embryogenesis, including cardiovascular development. SynT-derived factors and SynT within the placenta may play critical roles in ensuring proper organogenesis of other organs in the embryo.

Placental Histopathologic Findings in the Setting of Prenatally Diagnosed Major Congenital Heart Disease

Objectives: Studies suggest an association between placenta and congenital heart disease (CHD). We evaluated placental pathologies associated with major CHD. Methods: A prospective study included fetuses with major CHD, identified by fetal echocardiography. Fetal Doppler of umbilical artery (UA), middle cerebral artery (MCA), and placental histopathology were assessed. Outcome was measured by mortality at one month of age. Results: 21 cases were analyzed. Hypoplastic left heart syndrome was the commonest lesion (23.8%). Significant differences were detected among categories regarding MCA systolic/diastolic (S/D) ratio & pulsatility index (p = 0.023; 0.036), respectively. Placental histopathologies were demonstrated in 18(85.7%), predominately involved fetal malperfusion lesions 16/21(76.2%), especially chorangiosis (33.3%). No significant association was detected between placental histopathological abnormalities and Doppler parameter, diagnostic category, or mortality. Conclusion: The high prevalence of abnormal placental histopathological findings in major fetal CHD provides additional evidence of placental-cardiac interlinkage. No association was detected between abnormal placental histopathology and fetal Doppler measurements or neonatal outcome of CHD.

Shared developmental pathways of the placenta and fetal heart

Congenital heart defects (CHD) remain the most common class of birth defect worldwide, affecting 1 in every 110 live births. A host of clinical and morphological indicators of placental dysfunction are observed in pregnancies complicated by fetal CHD and, with the recent emergence of single-cell sequencing capabilities, the molecular and physiological associations between the embryonic heart and developing placenta are increasingly evident. In CHD pregnancies, a hostile intrauterine environment may negatively influence and alter fetal development. Placental maldevelopment and dysfunction creates this hostile in-utero environment and may manifest in the development of various subtypes of CHD, with downstream perfusion and flow-related alterations leading to yet further disruption in placental structure and function. The adverse in-utero environment of CHD-complicated pregnancies is well studied, however the specific etiological role that the placenta plays in CHD development remains unclear. Many mouse and rat models have been used to characterize the relationship between CHD and placental dysfunction, but these paradigms present substantial limitations in the assessment of both the heart and placenta. Improvements in non-invasive placental assessment can mitigate these limitations and drive human-specific investigation in relation to fetal and placental development. Here, we review the clinical, structural, and molecular relationships between CHD and placental dysfunction, the CHD subtype-dependence of these changes, and the future of Placenta-Heart axis modeling and investigation.

The Placenta in Congenital Heart Disease: Form, Function and Outcomes

The maternal-fetal environment, controlled and modulated by the placenta, plays a critical role in the development and well-being of the fetus, with long-term impact through programming of lifelong health. The fetal cardiovascular system and placenta emerge at the same time embryologically, and thus placental form and function are altered in the presence of congenital heart disease (CHD). In this review, we report on what is known about the placenta from a structural and functional perspective when there is CHD. We describe the various unique pathologic findings as well as the diagnostic imaging tools used to characterize placental function in utero. With growing interest in the placenta, a standardized approach to characterizing placental pathology has emerged. Furthermore, application of ultrasonography techniques and magnetic resonance imaging now allow for insights into placental blood flow and functionality in vivo. An improved understanding of the intriguing relationship between the placenta and the fetal cardiovascular system will provide opportunities to develop novel ways to optimize outcomes. Once better understood, therapeutic modulation of placental function offered during the vulnerable period of fetal plasticity may be one of the most impactful ways to alter the course of CHD and its complications.

Neonatal Depression Is Associated With 1-Year Mortality in Critical Congenital Heart Disease

Background Low 5-minute Apgar scores (AS) are predictive of term and preterm neonatal mortality but have not been well studied in the critical congenital heart disease (CCHD) population. We analyzed US national vital statistics data to evaluate the association between neonatal depression (AS 0-3) and 1-year mortality in CCHD. Methods and Results We performed a retrospective cohort study using 2014 to 2018 Centers for Disease Control and Prevention cohort-linked birth certificate and infant death records. Five-minute AS were categorized as ≤3, 4 to 6, or ≥7. We calculated birth rates and associated mortality rates by AS group in infants with and without CCHD. Multivariable logistic regression analyzed neonatal, maternal, and pregnancy-related risk factors for neonatal depression and 1-year mortality. Of 11 642 neonates with CCHD (0.06% of all births), the 5.8% with AS 0 to 3 accounted for 23.3% of all 1-year CCHD mortality, with 69.9% of deaths occurring within 1 month of life. Gestational age at birth, growth restriction, extracardiac defects, race, and low maternal education were associated with an increased odds of AS 0 to 3 in neonates with CCHD relative to those with AS 7 to 10 on multivariable analysis. AS 0 to 3 was associated with 1-year CCHD mortality after adjusting for these factors, prenatal care, and delivery location (adjusted odds ratio, 14.57 [95% CI, 11.73-18.10]). Conclusions The AS is a routine clinical measure providing important prognostic information in CCHD. These findings suggest that prenatal and perinatal factors, beyond those included in current risk stratification tools, are important for CCHD outcomes. Multidisciplinary collaboration to understand the pathophysiology underlying neonatal depression may help identify interventions to improve CCHD mortality rates.

Third Trimester Umbilical Arterial Pulsatility Index is Associated with Neurodevelopmental Outcomes at 2-Years in Major Congenital Heart Disease

Major congenital heart disease (CHD) is associated with impaired neurodevelopment (ND), partly from prenatal insults. In this study we explore associations between 2nd and 3rd trimester umbilical (UA) and middle cerebral artery (MCA) pulsatility index (PI = systolic-diastolic velocities/mean velocity) in fetuses with major CHD and 2-year ND and growth outcomes. Eligible patients included those with a prenatal diagnosis of CHD from 2007 to 2017 without a genetic syndrome who underwent previously defined cardiac surgeries and 2-year biometric and ND assessments in our program. UA and MCA-PI Z-scores at fetal echocardiography were examined for relationships with 2-year Bayley Scales of Infant and Toddler Development and biometric Z-scores. Data from 147 children was analyzed. Second and 3rd trimester fetal echocardiograms were performed at 22.4 ± 3.7 and 34.7 ± 2.9 weeks (mean ± SD), respectively. Multivariable regression analysis showed an inverse relationship between 3rd trimester UA-PI for all CHD and cognitive - 1.98 (- 3.37, - 0.59), motor - 2.57 (- 4.15, - 0.99), and language - 1.67 (- 3.3, - 0.03) (effect size and 95th confidence interval) ND domains (p < 0.05), with the strongest relationships in the single ventricle and hypoplastic left heart syndrome subgroups. No association was found for 2nd trimester UA-PI or any trimester MCA-PI and ND or between UA or MCA-PI and 2-year growth parameters. Increased 3rd trimester UA-PI, reflecting an altered late gestation fetoplacental circulation, relates to worse 2-year ND in all domains.

Defects in placental syncytiotrophoblast cells are a common cause of developmental heart disease

Placental abnormalities have been sporadically implicated as a source of developmental heart defects. Yet it remains unknown how often the placenta is at the root of congenital heart defects (CHDs), and what the cellular mechanisms are that underpin this connection. Here, we selected three mouse mutant lines, Atp11a, Smg9 and Ssr2, that presented with placental and heart defects in a recent phenotyping screen, resulting in embryonic lethality. To dissect phenotype causality, we generated embryo- and trophoblast-specific conditional knockouts for each of these lines. This was facilitated by the establishment of a new transgenic mouse, Sox2-Flp, that enables the efficient generation of trophoblast-specific conditional knockouts. We demonstrate a strictly trophoblast-driven cause of the CHD and embryonic lethality in one of the three lines (Atp11a) and a significant contribution of the placenta to the embryonic phenotypes in another line (Smg9). Importantly, our data reveal defects in the maternal blood-facing syncytiotrophoblast layer as a shared pathology in placentally induced CHD models. This study highlights the placenta as a significant source of developmental heart disorders, insights that will transform our understanding of the vast number of unexplained congenital heart defects.

Placental delayed villous maturation is associated with fetal congenital heart disease

BACKGROUND

The placenta is crucial for the overall development and lifelong health of the fetus. Abnormal placental development and function occur in pregnancies with fetal congenital heart disease. However, studies that use standardized diagnostic criteria and incorporate control populations are lacking. This limits the generalizability of current research and the ability to determine the specific placental abnormalities associated with congenital heart disease.

OBJECTIVE

This study applied consensus statement guidelines (known as the Amsterdam criteria) for placental pathology interpretation to compare the frequency and pattern of abnormalities in pregnancies with fetal congenital heart disease to demographically matched control pregnancies and evaluate for differences in placental abnormalities by cardiac physiology.

STUDY DESIGN

A single-center retrospective cohort study was conducted from January 2013 to June 2019. Infants with a prenatal diagnosis of moderate-severe congenital heart disease who were born at ≥37 weeks of gestation were included. A control group born at ≥37 weeks of gestation but without fetal congenital heart disease or other major pregnancy complications was matched to the congenital heart disease group on maternal race and ethnicity and infant sex. Using the Amsterdam criteria, placental pathology findings were categorized as delayed villous maturation, maternal vascular malperfusion, fetal vascular malperfusion, and inflammatory lesions. The frequency of placental abnormalities was compared between groups, and logistic regression was performed to evaluate the association of clinical and sociodemographic factors with delayed villous maturation, maternal vascular malperfusion, and fetal vascular malperfusion.

RESULTS

There were 194 pregnancies with fetal congenital heart disease and 105 controls included, of whom 83% in the congenital heart disease group and 82% in the control group were of non-Hispanic White race and ethnicity. Compared with controls, pregnancies with fetal congenital heart disease had higher rates of delayed villous maturation (6% vs 19%; P<.001) and maternal vascular malperfusion (19% vs 34%; P=.007) but not fetal vascular malperfusion (6% vs 10%; P=.23). Infants with congenital heart disease with 2-ventricle anatomy displayed the highest odds of delayed villous maturation compared with controls (odds ratio, 5.5; 95% confidence interval, 2.2-15.7; P<.01). Maternal vascular malperfusion was 2.2 times higher (P=.02) for infants with 2-ventricle anatomy and 2.9 times higher (P=.02) for infants with single-ventricle physiology with pulmonic obstruction. Within the congenital heart disease group, delayed villous maturation was associated with higher maternal body mass index, polyhydramnios, larger infant birth head circumference, and infant respiratory support in the delivery room, whereas maternal vascular malperfusion was associated with oligohydramnios. In multivariable models adjusting for cardiac diagnosis, associations of delayed villous maturation persisted for infant birth head circumference (odds ratio, 1.2; 95% confidence interval, 1.0-1.5; P=.02) and infant respiratory support in the delivery room (odds ratio, 3.0; 95% confidence interval, 1.3-6.5; P=.007).

CONCLUSION

Pregnancies with fetal congenital heart disease displayed higher rates of delayed villous maturation and maternal vascular malperfusion than controls, suggesting that placental maldevelopment may relate to maternal factors. Future investigations are needed to determine the association of these abnormalities with postnatal infant outcomes.

HAND1 knockdown disrupts trophoblast global gene expression

Congenital heart disease (CHD) affects nearly 1% of births annually, and CHD pregnancies carry increased risk of developing pathologies of abnormal placentation. We previously reported significant developmental impacts of disrupting Hand1, a gene associated with CHD, expression in placenta trophoblast and endothelial cells in multiple mouse models. In this study, we aimed to build upon this knowledge and characterize the mechanistic impacts of disrupting HAND1 on human placenta trophoblast and vascular endothelial cell gene expression. HAND1 gene expression was silenced in BeWo cells, a choriocarcinoma model of human cytotrophoblasts, (n = 3-9 passages) and isolated human placental microvascular endothelial cells (HPMVEC; n = 3 passages), with HAND1 siRNA for 96 h. Cells were harvested, mRNA isolated and RNA sequencing performed using the Illumina NextSeq 550 platform. Normalization and differential gene expression analyses were conducted using general linear modeling in edgeR packages. Statistical significance was determined using a log2 fold change of >1.0 or < -1.0 and unadjusted p-value ≤0.05. Panther DB was used for overrepresentation analysis, and String DB for protein association network analysis. There was downregulation of 664 genes, and upregulation of 59 genes in BeWo cells with direct HAND1 knockdown. Overrepresentation analysis identified disruption to pathways including cell differentiation, localization, and cell projection organization. In contrast, only seven genes were changed with direct HAND1 knockdown in HPMVECs. Disruption to HAND1 expression significantly alters gene expression profile in trophoblast but not endothelial cells. This data provides further evidence that future studies on genetic perturbations in CHDs should consider the extra-embryonic tissue in addition to the fetal heart.

Patterns of placental injury in various types of fetal congenital heart disease

OBJECTIVES

Fetal blood circulation may be modified in congenital heart disease (CHD). This retrospective analysis was performed to study whether the type of CHD is associated with specific placental pathology.

METHODS

3 types of CHD based on presumed proportion of placental and systemic blood distribution in fetal circulation were analyzed: Group 1: 89 cases with low placental blood content (hypoplastic left heart syndrome, transposition of great arteries, coarctation of aorta), Group 2: 71 placentas with intermediate placental and systemic blood content due to increased intracardiac blood mixing (tetralogy of Fallot, truncus arteriosus, double inlet/outlet ventricle), and Group 3: 24 placentas with high placental blood content (tricuspid or pulmonary atresia, Ebstein anomaly). Frequencies of 27 independent clinical and 47 placental phenotypes of 184 placentas in those three groups were statistically compared.

RESULTS

The most advanced gestational age at delivery, and large vessel (global) fetal vascular malperfusion (FVM) were most common in Group 1, while macerated stillbirths, neonatal mortality, abnormal amniotic fluid volume (oligohydramnios or polyhydramnios), other congenital anomalies, distal villous lesions of FVM, placental edema and amnion nodosum were most common in Groups 2 and 3, although the frequencies of placental lesions were statistically not significant.

CONCLUSIONS

Left heart obstructive lesions potentially associated with brain maldevelopment show increase in lesions of global FVM (in aggregate and individually fetal vascular ectasia, stem vessel obliteration and intramural fibrin deposition) as may be seen in umbilical cord compromise. CHD with increased intracardiac blood mixing or with right heart defects is associated with average preterm gestational age at delivery and placental lesions of distal villous FVM, villous edema and amnion nodosum.

A guide to prenatal counseling regarding neurodevelopment in congenital heart disease

Advances in cardiac surgical techniques taking place over the past 50 years have resulted in the vast majority of children born with congenital cardiac malformations now surviving into adulthood. As the focus shifts from survival to the functional outcomes of our patients, it is increasingly being recognized that a significant proportion of patients undergoing infant cardiac repair experience adverse neurodevelopmental (ND) outcomes. The etiology of abnormal brain development in the setting of congenital heart disease is poorly understood, complex, and likely multifactorial. Furthermore, the efficacy of therapies available for the learning disabilities, attention deficit, and hyperactivity disorders and other ND deficits complicating congenital heart disease is currently uncertain. This situation presents a challenge for prenatal counseling as current antenatal testing does not usually provide prognostic information regarding the likely ND trajectories of individual patients. However, we believe it is important for parents to be informed about potential issues with child development when a new diagnosis of congenital heart disease is disclosed. Parents deserve a comprehensive and thoughtful approach to this subject, which conveys the uncertainties involved in predicting the severity of any developmental disorders encountered, while emphasizing the improvements in outcomes that have already been achieved in infants with congenital heart disease. A balanced approach to counseling should also discuss what local arrangements are in place for ND follow-up. This review presents an up-to-date overview of ND outcomes in patients with congenital heart disease, providing possible approaches to communicating this information to parents during prenatal counseling in a sensitive and accurate manner.

Prenatal prediction of Shone's complex. The role of the degree of ventricular disproportion and speckle-tracking analysis

OBJECTIVES

Shone's complex (SC) is characterized by sequential obstructions of left ventricular (LV) inflow and outflow. It can be associated with poor long-term prognosis when compared to Simple-Aortic Coarctation (S-CoA). We aimed to assess whether the degree of ventricular disproportion and 2D-speckle-tracking echocardiography (2D-STE) could improve the accuracy of prenatal prediction of SC.

METHODS

75 consecutive fetuses were retrospectively enrolled from January 2010 to June 2021. Fetuses were divided into 4 groups (Group 1: SC; Group 2: S-CoA; Group 3: False Positive-Coarctation of the Aorta [FP-CoA]; group 4: controls). Comparisons for echocardiographic measures and myocardial deformation indices were performed. A receiver operating characteristic (ROC) analysis was performed on the MV/TV (mitral valve/tricuspid valve ratio) and LV GLS (global longitudinal strain) values to identify cut-offs to separate group 1 and 2 fetuses.

RESULTS

SC fetuses showed a significant reduction in MV/TV when compared to S-CoA and FP-CoA fetuses (p<0.001). LV GLS in SC fetuses was significantly reduced compared to S-CoA fetuses (-13.3 ± 2.1% vs. -17.0 ± 2.2%, p=0.001). A cut-off value of 0.59 for MV/TV and -15.35% for LV GLS yielded a sensitivity of 76 and 82% and a specificity of 71 and 83% respectively in separating SC vs. S-CoA fetuses.

CONCLUSIONS

SC fetuses showed a more severe degree of ventricular disproportion and a lower LV GLS compared to S-CoA, FP-CoA and control fetuses. MV/TV and GLS are both predictors of SC. These findings may improve the quality of prenatal parental counselling.

Optimizing Neurodevelopmental Outcomes in Neonates With Congenital Heart Disease

Neurodevelopmental impairment is a common and important long-term morbidity among infants with congenital heart disease (CHD). More than half of those with complex CHD will demonstrate some form of neurodevelopmental, neurocognitive, and/or psychosocial dysfunction requiring specialized care and impacting long-term quality of life. Preventing brain injury and treating long-term neurologic sequelae in this high-risk clinical population is imperative for improving neurodevelopmental and psychosocial outcomes. Thus, cardiac neurodevelopmental care is now at the forefront of clinical and research efforts. Initial research primarily focused on neurocritical care and operative strategies to mitigate brain injury. As the field has evolved, investigations have shifted to understanding the prenatal, genetic, and environmental contributions to impaired neurodevelopment. This article summarizes the recent literature detailing the brain abnormalities affecting neurodevelopment in children with CHD, the impact of genetics on neurodevelopmental outcomes, and the best practices for neonatal neurocritical care, focusing on developmental care and parental support as new areas of importance. A framework is also provided for the infrastructure and resources needed to support CHD families across the continuum of care settings.

The Relationship Between Placental Pathology and Neurodevelopmental Outcomes in Complex Congenital Heart Disease

Complex congenital heart disease (CCHD) is associated with impaired neurodevelopmental outcomes. Peri- and post-operative factors are known contributors while the impact of the prenatal environment is not yet delineated. Variations in fetal circulation, seen in transposition of the great arteries (TGA) and single ventricular physiology (SVP), are associated with placenta abnormalities. These abnormalities may be associated with placental insufficiency, a risk factor for poor neurodevelopmental outcomes. We hypothesized there is a correlation between placental pathology and impaired neurodevelopmental outcomes in patients with CCHD. We performed a single center retrospective cohort study with patients with TGA and SVP from 2010 to 2017 at Children's Wisconsin. Patient variables were obtained from the medical record. Bayley Scales of Infant Development Third Edition standard scores for cognitive, motor, and language performance were collected from neurodevelopmental visits. Placenta pathology reports were reviewed with tabulation of predetermined anatomical and pathological characteristics. We identified 79 patients in our cohort and 61 (77.2%) had abnormal placentas. There was no significant difference between the two groups in any demographic or clinical variables. For cognitive and motor performance, without adjusting for the covariates, infants with placental abnormalities had significantly lower scores compared to infants without (p = 0.026, p = 0.045 respectively). Conversely, there was no significant difference in language scores between the two groups (p = 0.12). Placenta abnormalities are common in patients with CCHD, and placenta abnormalities are associated with impaired neurodevelopmental outcomes. These results underscore the complex causal pathways of neurodevelopmental impairment in infants with CCHD and offer opportunities for targeted postnatal developmental interventions after discharge.

Near-Term Cerebroplacental Doppler, Heart Morphology, and Neonatal Biometry in Hypoplastic Left Heart Syndrome

OBJECTIVES

To analyze near-term cerebroplacental Doppler, heart morphology, and neonatal biometry in isolated hypoplastic left heart syndrome (HLHS) relative to healthy controls.

METHODS

This retrospective study included 55 fetuses with HLHS (29 with mitral valve stenosis [MS]/aortic valve atresia [AA], 14 with MS/aortic valve stenosis, and 12 with mitral valve atresia [MA]/[AA]) diagnosed prenatally between 2010 and 2019 at 2 referral centers and 101 healthy controls. Ultrasound assessment included umbilical artery (UA), middle cerebral artery (MCA) pulsatility index (PI), and cerebroplacental ratio (CPR), with neonatal weight, length, head circumference (HC), Apgar score, and UA pH measured at birth.

RESULTS

In total, 32.7% of HLHS fetuses had abnormal MCA-PI and UA-PI, and 38.2% had CPRs below the fifth percentile before birth. All tested Doppler parameters differed from those of the healthy controls (P ≤ .01). Birth weight and length were comparable between HLHS and control fetuses, whereas birth HCs were smaller in the HLHS group than in the control group (P = .018). In both groups, increased UA-PI correlated with lower birth weight, but only HLHS fetuses with UA-PI > the 95th percentile had a lower median HC at birth than those with normal UA-PI (P = .045). The median UA-PI percentile was higher in fetuses with MA than in fetuses with MS (P = .015). The ascending aortic diameter correlated with birth weight (P = .036) and birth length (P = .039).

CONCLUSION

Abnormal cerebroplacental hemodynamics are evident in a high percentage of near-term fetuses with HLHS, and increased placental resistance may contribute to birth weight and HC. Moreover, heart morphology may impact placental circulation and neonatal biometry.

Prenatal Diagnosis of Congenital Heart Diseases and Associations with Serum Biomarkers of Aneuploidy: A Multicenter Prospective Cohort Study

PURPOSE

We assessed prenatal detection rates of congenital heart disease (CHD) and associations between maternal serum biomarkers and non-chromosomal CHD in singleton pregnancies.

MATERIALS AND METHODS

This study was conducted as a secondary analysis of data obtained during a multicenter prospective cohort study that investigated the cost-effectiveness of prenatal testing for fetal aneuploidy. We analyzed the prenatal detection rate and accuracy for CHD screening via ultrasound during the second trimester, as well as associations between serum biomarkers and CHDs, in singleton newborns without chromosomal abnormalities.

RESULTS

Among 6715 women, 142 (2.1%) newborns were born with CHDs, of which 67 (1.0%) newborns had major CHDs. The prenatal detection rate for all CHDs and major CHDs were 34.5% and 58.2%, respectively. After excluding isolated ventricular septal defects, the detection rate for critical CHDs was 85.9%. Women with low pregnancy-associated plasma protein A (PAPP-A) (<0.4 multiples of the median, MOM) face increased risks of non-chromosomal CHDs [adjusted odds ratio (aOR) 2.76; 95% confidence interval (CI) 1.36-5.13] and major CHDs (aOR 7.30; 95% CI 3.18-15.59), compared to those without CHDs. A higher inhibin A level (≥2.5 MOM; aOR 4.84; 95% CI 1.42-12.46) was associated with non-chromosomal major CHDs.

CONCLUSION

Ultrasonography performed during the second trimester by obstetricians detected over 85% of critical CHDs. Low maternal serum PAPP-A or high inhibin-A was associated with non-chromosomal CHDs. These results may contribute to an improvement in prenatal diagnosis of CHDs.

Preoperative Care of Neonates With Congenital Heart Disease

Congenital heart disease (CHD) is one of the most common types of birth defects, with 40,000 newborns diagnosed yearly in the United States. This article describes: (1) four common heart defects seen in neonatal intensive care units, (2) the typical medical/nursing care of these neonates, and (3) common surgical management for the defects. Hypoplastic left heart syndrome, dextro-transposition of the great arteries, tetralogy of Fallot, and pulmonary atresia with intact ventricular septum are four common types of CHD requiring NICU admission. Knowledge of these defects will help nurses to appropriately manage and treat neonates with these types of CHD.

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.

The Effect of Size and Asymmetry at Birth on Brain Injury and Neurodevelopmental Outcomes in Congenital Heart Disease

Poor and asymmetric fetal growth have been associated with neonatal brain injury (BI) and worse neurodevelopmental outcomes (NDO) in the growth-restricted population due to placental insufficiency. We tested the hypothesis that postnatal markers of fetal growth (birthweight (BW), head circumference (HC), and head to body symmetry) are associated with preoperative white matter injury (WMI) and NDO in infants with single ventricle physiology (SVP) and d-transposition of great arteries (TGA). 173 term newborns (106 TGA; 67 SVP) at two sites had pre-operative brain MRI to assess for WMI and measures of microstructural brain development. NDO was assessed at 30 months with the Bayley Scale of Infant Development-II (n = 69). We tested the association between growth parameters at birth with the primary outcome of WMI on the pre-operative brain MRI. Secondary outcomes included measures of NDO. Newborns with TGA were more likely to have growth asymmetry with smaller heads relative to weight while SVP newborns were symmetrically small. There was no association between BW, HC or asymmetry and WMI on preoperative brain MRI or with measures of microstructural brain development. Similarly, growth parameters at birth were not associated with NDO at 30 months. In a multivariable model only cardiac lesion and site were associated with NDO. Unlike other high-risk infant populations, postnatal markers of fetal growth including head to body asymmetry that is common in TGA is not associated with brain injury or NDO. Lesion type appears to play a more important role in NDO in CHD.

Birthweight and isolated congenital heart defects - A systematic review and meta-analysis

Background

Birthweight (BW) is an important prognostic factor in newborns with congenital heart defects (CHD).

Objectives

To give an overview of the literature on BW z‐score in children with isolated CHD.

Search strategy

A systematic search was performed on isolated CHD and BW in PubMed, Embase, Web of Science, COCHRANE Library and Emcare.

Selection criteria

Neonates with isolated CHD were included if a BW percentile, BW z‐score or % small‐or‐gestational age (SGA) was reported.

Data collection and analysis

BW z‐score and percentage SGA were pooled with random‐effect meta‐analysis. Quality and risk of bias were assessed using the modified Newcastle Ottawa Scale.

Main results

Twenty‐three articles (27 893 cases) were included. BW z‐scores were retrieved from 11 articles, resulting in a pooled z‐score of −0.20 (95% CI −0.50 to 0.11). The overall pooled prevalence of SGA <10th percentile was 16.0% (95% CI 11.4–20.5; 14 studies). Subgroup analysis of major CHD showed similar results (BW z‐score −0.23 and percentage SGA 16.2%).

Conclusions

Overall BW in isolated CHD is within range of normality but impaired, with a 1.6‐fold higher risk of SGA, irrespective of the type of CHD (major CHD vs all CHD combined). Our findings underline the association between CHD and BW. The use of BW z‐scores provides insight into growth of all fetuses with CHD.

Tweetable abstract

Infants with a congenital heart defect (CHD) have a lower birthweight z‐score and a higher incidence of small‐for‐gestational age (<10th percentile). This was encountered both in the major CHD‐group as well as in all‐CHD combined group analysis. Future research on the association between birthweight and CHD should include all types of CHDs (including mild cardiac defects) and placental‐related disease, such as pre‐eclampsia. We advocate the use of international standardised fetal growth and birthweight charts in CHD research.

Infants with a congenital heart defect (CHD) have a lower birthweight z‐score and a higher incidence of small‐for‐gestational age (<10th percentile). This was encountered both in the major CHD‐group as well as in all‐CHD combined group analysis. Future research on the association between birthweight and CHD should include all types of CHDs (including mild cardiac defects) and placental‐related disease, such as pre‐eclampsia. We advocate the use of international standardised fetal growth and birthweight charts in CHD research.

Altered erythropoiesis in newborns with congenital heart disease

BACKGROUND

Fetal hypoxia has been implicated in fetal growth restriction in congenital heart disease (CHD) and leads to stress erythropoiesis in utero. The objective is to assess erythropoiesis and its association with growth in newborns with CHD.

METHODS

Fetuses with prenatally diagnosed CHD from 2013 to 2018 were retrospectively reviewed. Pregnancies with multiple gestation, genetic abnormalities, major extra-cardiac anomalies, and placental abruption were excluded. Complete blood count tests at birth were compared to published normative values. Spearman correlation assessed associations of red blood cell (RBC) indices with birth anthropometrics and prenatal Doppler measures.

RESULTS

A total of 160 newborns were included. Median gestational age was 38.3 (37.3, 39.0) weeks. Infants ≥37 weeks gestation had lower hemoglobin (Hgb), hematocrit, and elevated nucleated RBC (nRBC), mean corpuscular volume, and mean corpuscular hemoglobin compared to reference. No differences in RBC indices were observed in infants <34 and 34-37 weeks gestation. There was no difference in Hgb and nRBC between CHD subgroups. Neither Hgb nor nRBC were associated with birth anthropometrics or Doppler patterns.

CONCLUSIONS

Term infants with CHD demonstrated multiple alterations in erythrocyte indices suggesting ineffective stress erythropoiesis in late gestation resulting in lower Hgb at birth. Altered erythropoiesis was not correlated to growth or Doppler patterns.

IMPACT

Newborns with congenital heart disease (CHD) born at term gestation demonstrated altered erythropoiesis. Term newborns with CHD have decreased hemoglobin levels despite having red blood cell indices consistent with stress erythropoiesis, suggesting an incomplete compensatory response to in utero physiologic disturbances associated with CHD. The etiology is unknown; however, it may be influenced by multiple risk factors during pregnancy in the maternal-fetal dyad. Alterations in red blood cell indices were not associated with outcomes of fetal growth.

Analysis of Placental Arteriovenous Formation Reveals New Insights Into Embryos With Congenital Heart Defects

The placental vasculature provides the developing embryo with a circulation to deliver nutrients and dispose of waste products. However, in the mouse, the vascular components of the chorio-allantoic placenta have been largely unexplored due to a lack of well-validated molecular markers. This is required to study how these blood vessels form in development and how they are impacted by embryonic or maternal defects. Here, we employed marker analysis to characterize the arterial/arteriole and venous/venule endothelial cells (ECs) during normal mouse placental development. We reveal that placental ECs are potentially unique compared with their embryonic counterparts. We assessed embryonic markers of arterial ECs, venous ECs, and their capillary counterparts-arteriole and venule ECs. Major findings were that the arterial tree exclusively expressed Dll4, and venous vascular tree could be distinguished from the arterial tree by Endomucin (EMCN) expression levels. The relationship between the placenta and developing heart is particularly interesting. These two organs form at the same stages of embryogenesis and are well known to affect each other's growth trajectories. However, although there are many mouse models of heart defects, these are not routinely assessed for placental defects. Using these new placental vascular markers, we reveal that mouse embryos from one model of heart defects, caused by maternal iron deficiency, also have defects in the formation of the placental arterial, but not the venous, vascular tree. Defects to the embryonic cardiovascular system can therefore have a significant impact on blood flow delivery and expansion of the placental arterial tree.

Impact of Maternal-Fetal Environment on Mortality in Children With Single Ventricle Heart Disease

BACKGROUND

Children with single ventricle heart disease have significant morbidity and mortality. The maternal–fetal environment (MFE) may adversely impact outcomes after neonatal cardiac surgery. We hypothesized that impaired MFE would be associated with an increased risk of death after stage 1 Norwood reconstruction.

METHODS AND RESULTS

We performed a retrospective cohort study of children with hypoplastic left heart syndrome (and anatomic variants) who underwent stage 1 Norwood reconstruction between 2008 and 2018. Impaired MFE was defined as maternal gestational hypertension, preeclampsia, gestational diabetes, and/or smoking during pregnancy. Cox proportional hazards regression models were used to investigate the association between impaired MFE and death while adjusting for confounders. Hospital length of stay was assessed with the competing risk of in‐hospital death. In 273 children, the median age at stage 1 Norwood reconstruction was 4 days (interquartile range [IQR], 3–6 days). A total of 72 children (26%) were exposed to an impaired MFE; they had more preterm births (18% versus 7%) and a greater percentage with low birth weights <2.5 kg (18% versus 4%) than those without impaired MFE. Impaired MFE was associated with a higher risk of death (hazard ratio [HR], 6.05; 95% CI, 3.59–10.21; P<0.001) after adjusting for age at surgery, Hispanic ethnicity, genetic syndrome, cardiac diagnosis, surgeon, and birth era. Children with impaired MFE had almost double the risk of prolonged hospital stay (HR, 1.95; 95% CI, 1.41–2.70; P<0.001).

CONCLUSIONS

Children exposed to an impaired MFE had a higher risk of death following stage 1 Norwood reconstruction. Prenatal exposures are potentially modifiable factors that can be targeted to improve outcomes after pediatric cardiac surgery.

Environmental Exposures and Congenital Heart Disease

Congenital heart disease (CHD) is the most common congenital abnormality worldwide, affecting 8 to 12 infants per 1000 births globally and causing >40% of prenatal deaths. However, its causes remain mainly unknown, with only up to 15% of CHD cases having a determined genetic cause. Exploring the complex relationship between genetics and environmental exposures is key in understanding the multifactorial nature of the development of CHD. Multiple population-level association studies have been conducted on maternal environmental exposures and their association with CHD, including evaluating the effect of maternal disease, medication exposure, environmental pollution, and tobacco and alcohol use on the incidence of CHD. However, these studies have been done in a siloed manner, with few examining the interplay between multiple environmental exposures. Here, we broadly and qualitatively review the current literature on maternal and paternal prenatal exposures and their association with CHD. We propose using the framework of the emerging field of the exposome, the environmental complement to the genome, to review all internal and external prenatal environmental exposures and identify potentiating or alleviating synergy between exposures. Finally, we propose mechanistic pathways through which susceptibility to development of CHD may be induced via the totality of prenatal environmental exposures, including the interplay between placental and cardiac development and the internal vasculature and placental morphology in early stages of pregnancy.

Neuroplacentology in congenital heart disease: placental connections to neurodevelopmental outcomes

Children with congenital heart disease (CHD) are living longer due to effective medical and surgical management. However, the majority have neurodevelopmental delays or disorders. The role of the placenta in fetal brain development is unclear and is the focus of an emerging field known as neuroplacentology. In this review, we summarize neurodevelopmental outcomes in CHD and their brain imaging correlates both in utero and postnatally. We review differences in the structure and function of the placenta in pregnancies complicated by fetal CHD and introduce the concept of a placental inefficiency phenotype that occurs in severe forms of fetal CHD, characterized by a myriad of pathologies. We propose that in CHD placental dysfunction contributes to decreased fetal cerebral oxygen delivery resulting in poor brain growth, brain abnormalities, and impaired neurodevelopment. We conclude the review with key areas for future research in neuroplacentology in the fetal CHD population, including (1) differences in structure and function of the CHD placenta, (2) modifiable and nonmodifiable factors that impact the hemodynamic balance between placental and cerebral circulations, (3) interventions to improve placental function and protect brain development in utero, and (4) the role of genetic and epigenetic influences on the placenta-heart-brain connection. IMPACT: Neuroplacentology seeks to understand placental connections to fetal brain development. In fetuses with CHD, brain growth abnormalities begin in utero. Placental microstructure as well as perfusion and function are abnormal in fetal CHD.

Placental and fetal characteristics of the Ohia mouse line recapitulate outcomes in human hypoplastic left heart syndrome

Congenital heart defects (CHDs) are the most common birth defect worldwide. The morbidity and mortality associated with these defects is compounded by increased frequency of fetal growth abnormalities. In the Ohia mouse model of hypoplastic left heart syndrome (HLHS), the double homozygous genotype is embryonically lethal at mid-pregnancy; a time in which optimal establishment of the placenta is crucial to fetal survival. We aimed to characterize placental and fetal growth and development in the double heterozygous genotype (Sap130^m/+Pcdha9^m/+). There was a shift in frequency of fetuses with reduced weight near term in the Sap130^m/+Pcdha9^m/+ fetuses compared to wildtype, driven by lower fetal weight in male fetuses compared to female. This shift in fetal weight distribution in the Sap130^m/+Pcdha9^m/+ fetuses was associated with reduced labyrinth region area (P < 0.001) and reduced fetal capillary density (P < 0.001) in the placentas, the latter being significantly lower in male Sap130^m/+Pcdha9^m/+ placentas compared to female. mRNA expression of several nutrient transporters was also lower in placentas from males compared to placentas from females, irrespective of genotype. Overall, this data shows that whilst the double heterozygous fetuses do not carry heart defects, placental development and function is impaired, particularly in males. Such differences are similar to findings in studies of human placentas and highlights the importance of this mouse model in continuing to understand the developmental links and disruptions to the heart-placenta axis.

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.

A mouse model of hypoplastic left heart syndrome demonstrating left heart hypoplasia and retrograde aortic arch flow

In hypoplastic left heart syndrome (HLHS), the mechanisms leading to left heart hypoplasia and their associated fetal abnormalities are largely unknown. Current animal models have limited utility in resolving these questions as they either do not fully reproduce the cardiac phenotype, do not survive to term and/or have very low disease penetrance. Here, we report the development of a surgically induced mouse model of HLHS that overcomes these limitations. Briefly, we microinjected the fetal left atrium of embryonic day (E)14.5 mice with an embolizing agent under high-frequency ultrasound guidance, which partially blocks blood flow into the left heart and induces hypoplasia. At term (E18.5), all positively embolized mice exhibit retrograde aortic arch flow, non-apex-forming left ventricles and hypoplastic ascending aortas. We thus report the development of the first mouse model of isolated HLHS with a fully penetrant cardiac phenotype and survival to term. Our method allows for the interrogation of previously intractable questions, such as determining the mechanisms of cardiac hypoplasia and fetal abnormalities observed in HLHS, as well as testing of mechanism-based therapies, which are urgently lacking.

Hypoplastic left heart syndrome (HLHS): molecular pathogenesis and emerging drug targets for cardiac repair and regeneration

INTRODUCTION

Hypoplastic left heart syndrome (HLHS) is a severe developmental defect characterized by the underdevelopment of the left ventricle along with aortic and valvular defects. Multiple palliative surgeries are required for survival. Emerging studies have identified potential mechanisms for the disease onset, including genetic and hemodynamic causes. Genetic variants associated with HLHS include transcription factors, chromatin remodelers, structural proteins, and signaling proteins necessary for normal heart development. Nonetheless, current therapies are being tested clinically and have shown promising results at improving cardiac function in patients who have undergone palliative surgeries.

AREAS COVERED

We searched PubMed and clinicaltrials.gov to review most of the mechanistic research and clinical trials involving HLHS. This review discusses the anatomy and pathology of HLHS hearts. We highlight some of the identified genetic variants that underly the molecular pathogenesis of HLHS. Additionally, we discuss some of the emerging therapies and their limitations for HLHS.

EXPERT OPINION

While HLHS etiology is largely obscure, palliative therapies remain the most viable option for the patients. It is necessary to generate animal and stem cell models to understand the underlying genetic causes directly leading to HLHS and facilitate the use of gene-based therapies to improve cardiac development and regeneration.

Conditional Mutation of Hand1 in the Mouse Placenta Disrupts Placental Vascular Development Resulting in Fetal Loss in Both Early and Late Pregnancy

Congenital heart defects (CHD) affect approximately 1% of all live births, and often require complex surgeries at birth. We have previously demonstrated abnormal placental vascularization in human placentas from fetuses diagnosed with CHD. Hand1 has roles in both heart and placental development and is implicated in CHD development. We utilized two conditionally activated Hand1^A126fs/+ murine mutant models to investigate the importance of cell-specific Hand1 on placental development in early (Nkx2-5^Cre) and late (Cdh5^Cre) pregnancy. Embryonic lethality occurred in Nkx2-5^Cre/Hand1^A126fs/+ embryos with marked fetal demise occurring after E10.5 due to a failure in placental labyrinth formation and therefore the inability to switch to hemotrophic nutrition or maintain sufficient oxygen transfer to the fetus. Labyrinthine vessels failed to develop appropriately and vessel density was significantly lower by day E12.5. In late pregnancy, the occurrence of Cdh5^Cre+;Hand1^A126fs/+ fetuses was reduced from 29% at E12.5 to 20% at E18.5 and remaining fetuses exhibited reduced fetal and placental weights, labyrinth vessel density and placenta angiogenic factor mRNA expression. Our results demonstrate for the first time the necessity of Hand1 in both establishment and remodeling of the exchange area beyond early pregnancy and in patterning vascularization of the placental labyrinth crucial for maintaining pregnancy and successful fetal growth.

Placenta morphology and biomarkers in pregnancies with congenital heart disease - A systematic review

Impaired placentation is an important contributing factor to intra-uterine growth restriction and pre-eclampsia in fetuses with congenital heart defects (CHD). These pregnancy complications occur more frequently in pregnancies with fetal CHD. One of the most important factors influencing the life of children with CHD is neurodevelopmental delay, which seems to start already in utero. Delayed neurodevelopment in utero may be correlated or even (partly) explained by impaired placentation in CHD cases. This systematic review provides an overview of published literature on placental development in pregnancies with fetal CHD. A systematic search was performed and the Newcastle-Ottawa scale was used to access data quality. Primary outcomes were placenta size and weight, vascular and villous architecture, immunohistochemistry, angiogenic biomarkers and/or placental gene expression. A total of 1161 articles were reviewed and 21 studies were included. Studies including CHD with a genetic disorder or syndrome and/or multiple pregnancies were excluded. Lower placental weight and elevated rates of abnormal umbilical cord insertions were found in CHD. Cases with CHD more frequently showed microscopic placental abnormalities (i.e. abnormal villous maturation and increased maternal vascular malperfusion lesions), reduced levels of angiogenic biomarkers and increased levels of anti-angiogenic biomarkers in maternal serum and umbilical cord blood. Altered gene expression involved in placental development and fetal growth were found in maternal serum and CHD placentas. In conclusion, abnormal placentation is found in CHD. More extensive studies are needed to elucidate the contribution of impaired placentation to delayed neurodevelopment in CHD cases.

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.

Placental abnormalities in congenital heart disease

Congenital heart disease (CHD) remains the most common birth defect in infants, and critical CHD is associated with significant rates of morbidity and mortality. With the advent of powerful yet noninvasive advanced fetal imaging, it is becoming increasingly evident that the presence of CHD in utero disrupts typical development and contributes to the lifelong morbidity in this population. Across healthy and high-risk populations, intrauterine influences can permanently alter fetal development that may manifest in complex morbidities later in life, the so-called fetal-onset-of-adult-disease (FOAD) phenomenon. The placenta plays a critical role in not only supporting fetal development, but also by adapting to specific intrauterine conditions. The role of placental health, adaptation and dysfunction, however, in CHD is not well understood. In this article, we will review current evidence relating placental health in CHD, appraise existing knowledge-gaps in the field and highlight promising new avenues to better understand the impact of placental function on fetal well-being. We will review evidence of ex vivo human placental studies that describe abnormal placental findings in pregnancies complicated by CHD, as well evidence for in vivo assessments of the human placenta. While overall clinical in vivo assessments of placental development are rather limited, we will also review emerging evidence from advanced quantitative and functional magnetic resonance imaging that are bringing new insights into placental structure and function throughout gestation. By providing novel information about placental development, we can now explore the maternal-fetal-placental connection in greater detail, and better understand the multi-factorial mechanisms that may contribute to adverse outcomes seen in survivors of CHD.

Seasonality of Hypoplastic Left Heart Syndrome and Single Ventricle Heart in Poland in the Context of Air Pollution

Hypoplastic left heart syndrome (HLHS) and single ventricle (SV) remain a significant cause of cardiac deaths occurring in the first week of life. Their pathogenesis and seasonal frequency are still unknown. Therefore, we attempt to look at the genesis of the HLHS and SV in the context of territorial distribution as well as seasonality. A total of 193 fetuses diagnosed with HLHS and 92 with SV were selected. The frequency was analyzed depending on the year, calendar month, quarter and season (fall-winter vs. spring-summer). The spatial distribution of HLHS and SV in Poland was analyzed. We observed a statistically significant overrepresentation of HLHS formation frequency in March: 27 (14.00%) in comparison to a monthly median of 15 (IQR: 13.75-16.25; p = 0.039), as well as a significantly higher frequency of HLHS in 2007-2009: 65 cases (33.68%) in comparison to the annual mean of 13.79 ± 6.36 (p < 0.001). We noted a higher frequency of SV among parous with the last menstrual period reported in the fall/winter season of 58 vs. 34 in the spring/summer season (p = 0.014). The performed analysis also revealed significant SV overrepresentation in 2008: 11 cases (12.00%) in comparison to the annual mean of 6.57 ± 2.71 (p = 0.016). Every single case of HLHS was observed when the concentration of benzo(a)pyrene and/or PM10 exceeded the acceptable/target level. Our research indicates that both the season and the level of pollution are significant factors affecting the health of parous women and their offspring. The reason why HLHS and SV develop more frequently at certain times of the year remains unclear, therefore research on this topic should be continued, as well as on the effects of PM10 and benzo(a)pyrene exposure.

The Association of Fetal Congenital Cardiac Defects and Placental Vascular Malperfusion

OBJECTIVES

Abnormal early angiogenesis appears to impact both placental disorders and fetal congenital heart defects (CHD). We sought to assess the association of placental perfusion defects (PPD) and fetal (CHD).

METHODS

Singleton pregnancies with isolated severe fetal CHD were compared to controls without congenital anomalies or maternal malperfusion (MVM) risk factors. CHD was categorized into group 1: single left ventricle morphology and transposition of the great vessels (TGA) and group 2: single right ventricle and two ventricle morphology. Malperfusion was defined as fetal vascular malperfusion (FVM), MVM, and both FVM and MVM.

RESULTS

PPD was increased for all CHD (n = 47), CHD with or without risk factors, and CHD groups compared to controls (n = 92). Overall CHD cases and CHD with risk factors had an increased risk of FVM (30% and 80% vs 14%), and MVM (43% and 50% vs 21%), respectively. MVM rates were similar in CHD with and without maternal risk factors. FVM (38% vs 14%) and MVM (44% vs 21%) were increased in Group 1. MVM (42% vs 21%) and both FVM and MVM (16% vs 3%) were increased in Group 2.

CONCLUSIONS

PPD risk is increased in severe isolated fetal CHD. The highest risk is seen in fetal CHD with maternal risk factors.

Cerebral Blood Flow Monitoring in High-Risk Fetal and Neonatal Populations

Cerebrovascular pressure autoregulation promotes stable cerebral blood flow (CBF) across a range of arterial blood pressures. Cerebral autoregulation (CA) is a developmental process that reaches maturity around term gestation and can be monitored prenatally with both Doppler ultrasound and magnetic resonance imaging (MRI) techniques. Postnatally, there are key advantages and limitations to assessing CA with Doppler ultrasound, MRI, and near-infrared spectroscopy. Here we review these CBF monitoring techniques as well as their application to both fetal and neonatal populations at risk of perturbations in CBF. Specifically, we discuss CBF monitoring in fetuses with intrauterine growth restriction, anemia, congenital heart disease, neonates born preterm and those with hypoxic-ischemic encephalopathy. We conclude the review with insights into the future directions in this field with an emphasis on collaborative science and precision medicine approaches.

The placenta as the window to congenital heart disease

PURPOSE OF REVIEW

There is an increasing recognition that structural abnormalities and functional changes in the placenta can have deleterious effects on the development of the fetal heart. This article reviews the role of the placenta and the potential impact of placental insufficiency on fetuses with congenital heart disease.

RECENT FINDINGS

The fetal heart and the placenta are directly linked because they develop concurrently with shared regulatory and signaling pathways. Placental disease is more common in pregnancies carrying a fetus with congenital heart disease and the fetal response to placental insufficiency may lead to the postnatal persistence of cardiac remodeling. The mechanisms underlying this placental-fetal axis of interaction potentially include genetic factors, oxidative stress, chronic hypoxia, and/or angiogenic imbalance.

SUMMARY

The maternal-placental-fetal circulation is critical to advancing our understanding of congenital heart disease. We must first expand our ability to detect, image, and quantify placental insufficiency and dysfunction in utero. Elucidating the modifiable factors involved in these pathways is an exciting opportunity for future research, which may enable us to improve outcomes in patients with congenital heart disease.

Prevalence of Growth Restriction at Birth for Newborns With Congenital Heart Defects: A Population-Based Prospective Cohort Study EPICARD

Background and Objectives: Congenital heart defects (CHD) and growth restriction at birth are two major causes of childhood and adult morbidity and mortality. The aim of this study was to assess the overall risk of growth restriction at birth, as measured by its imperfect proxy small (< 10th percentile) for gestational age (SGA), for newborns with CHD. Methods: Using data from a population-based cohort of children born with CHD, we assessed the risk of growth restriction at birth using SGA and severe SGA (3rd percentile). To compare the odds of SGA and severe SGA across five specific major CHD, we used ordinal logistic regression using isolated, minor (non-operated) ventricular septal defect (VSD) as the control group. Results: The overall proportion of SGA for "isolated" CHD (i.e., those not associated with other anomalies) was 13% (95% CI, 12-15%), which is 30% higher than what would be expected in the general population (i.e., 10%). The risk of severe SGA was 5% (95% CI, 4-6%) as compared with the expected 3% in the general population. There were substantial differences in the risk of overall SGA and more so severe SGA across the different CHD. The highest risk of SGA occurred for Tetralogy of Fallot (adjusted OR 2.7, 95% CI, 1.3-5.8) and operated VSD (adjusted OR 2.1, 95% CI, 1.1-3.8) as compared with the control group of minor (non-operated) VSD. Conclusion: The overall risks of both SGA and severe SGA were higher in isolated CHD than what would be expected in the general population with substantial differences across the subtypes of CHD. These results may provide a clue for understanding the underlying mechanisms of the relation between alterations in fetal circulation associated with different types of CHD and their effects on fetal growth.

Unique features and emerging in vitro models of human placental development

Background

The placenta is an essential organ for the normal development of mammalian fetuses. Most of our knowledge on the molecular mechanisms of placental development has come from the analyses of mice, especially histopathological examination of knockout mice. Choriocarcinoma and immortalized cell lines have also been used for basic research on the human placenta. However, these cells are quite different from normal trophoblast cells.

Methods

In this review, we first provide an overview of mouse and human placental development with particular focus on the differences in the anatomy, transcription factor networks, and epigenetic characteristics between these species. Next, we discuss pregnancy complications associated with abnormal placentation. Finally, we introduce emerging in vitro models to study the human placenta, including human trophoblast stem (TS) cells, trophoblast and endometrium organoids, and artificial embryos.

Main findings

The placental structure and development differ greatly between humans and mice. The recent establishment of human TS cells and trophoblast and endometrial organoids enhances our understanding of the mechanisms underlying human placental development.

Conclusion

These in vitro models will greatly advance our understanding of human placental development and potentially contribute to the elucidation of the causes of infertility and other pregnancy complications.

Abnormalities of placental development and function are associated with the different fetal growth patterns of hypoplastic left heart syndrome and transposition of the great arteries

BACKGROUND

Birthweight is a critical predictor of congenital heart disease (CHD) surgical outcomes. Hypoplastic left heart syndrome (HLHS) is cyanotic CHD with known fetal growth restriction and placental abnormalities. Transposition of the great arteries (TGA) is cyanotic CHD with normal fetal growth. Comparison of the placenta in these diagnoses may provide insights on the fetal growth abnormality of CHD.

METHODS

Clinical data and placental histology from placentas associated with Transposition of the Great Arteries (TGA) were analyzed for gross pathology, morphology, maturity and vascularity and compared to both control and previously analyzed HLHS placentas [1]. RNA was isolated from HLHS, TGA and control placentas and sequenced by Illumina HiSeq.Transcriptome analysis was performed using AltAnalyze. Immunohistochemistry was utilized to assess placental nutrient transporter expression in all three groups.

RESULTS

Placental weight was reduced in TGA cases, and demonstrated reduced villous vasculature, immature terminal villi in the parenchyma compared to controls and reflected our previous data from HLHS placentas. However, birth weight was not reduced in TGA cases compared to controls in contrast to the HLHS cohort and birthweight:placental weight ratio was significantly increased in TGA cases but not HLHS compared to control. Transcriptomic and histologic analysis demonstrates reduced cell activity and nutrient transport capability in HLHS but not TGA placentas which appear to increase/maintain these mechanisms.

CONCLUSIONS

Despite common vascular disturbances in placentas from HLHAs and TGA, these do not account for the disparities in birthweights frequently seen between these CHD subtypes, in contrast our transcriptomic and histologic analyses reveal differentially regulated mechanisms between the subtypes that may explain these disparities.

Adverse perinatal outcome and placental abnormalities in pregnancies with major fetal congenital heart defects: A retrospective case-control study

OBJECTIVE

The placental development has been shown to be compromised in pregnancies affected by fetal congenital heart defects (CHD). This study aimed to investigate the frequency of complications related to utero-placental insufficiency in pregnancies with and without major CHD.

METHOD

This retrospective case-control study was conducted at a Fetal Echocardiography Center in Milan. The following outcomes were compared between the two groups: preeclampsia (PE), small for gestational age (SGA), placental disorders and preterm birth (PTB). The logistic regression analysis was adjusted for maternal age, parity, co-morbidities and mode of conception.

RESULTS

The CHD group (n = 480) showed significantly increased incidence of PE (2.9% vs 0.9%; aOR, 6.50; 95% CI, 1.39-30.41; P = .017) as compared to the control group (n = 456). Placental disorders occurred more frequently in the CHD than in controls, but the increased risk showed only a borderline significance (4.5% vs 3.3%; aOR, 2.56; 95% CI, 0.99-1.02; P = .046). There was a significantly higher risk of SGA in CHD than in controls (8.7% vs 3.9%; aOR, 3.37; 95% CI, 1.51-7.51; P = .003). PTB occurred in 65/477 (13.6%) cases and in 39/447 (8.7%) controls (P = .022) (aOR, 2.17; 95% CI, 1.24-3.81; P = .007).

CONCLUSION

Major CHD are significantly associated with the risk of PE, SGA and PTB.

Fetal Umbilical Arterial Pulsatility Correlates With 2-Year Growth and Neurodevelopmental Outcomes in Congenital Heart Disease

BACKGROUND

Children with congenital heart disease (CHD) are at risk of adverse long-term neurodevelopmental outcomes, believed to be, in part, secondary to prenatal insults. Placental pathology and altered fetal middle cerebral arterial (MCA) flow suggestive of brain sparing have been documented in fetal CHD. In the present study we investigated the relationship between MCA and umbilical arterial (UA) flow patterns in fetal transposition of the great arteries (d-TGA) and hypoplastic left heart syndrome (HLHS) and growth and 2-year neurodevelopmental outcomes.

METHODS

We included children with d-TGA and HLHS who had third-trimester fetal echocardiograms between 2004 and 2014, at which time umbilical artery (UA) and MCA pulsatility indices (PIs) were measured, and who underwent 2-year growth and neurodevelopmental assessments.

RESULTS

We identified 24 children with d-TGA and 36 with HLHS. Mean age at fetal echocardiography was 33.8 ± 3.5 weeks. At 2-year follow-up, head circumference z score (standard deviation [SD]) was -0.09 (1.07) and 0.17 (1.7) for the d-TGA and HLHS groups, respectively. Bayley III mean (SD) cognitive, language, and motor scores were 97.7 (10.8), 94.7 (13.4), and 98.6 (8.6) for the d-TGA group and 90.3 (13.9), 87.2 (17.5), and 85.3 (16.2) for the HLHS group. On multivariate linear regression analysis, UA-PI was associated (effect sizes [95% CI]) with length (-1.45 [-2.7, -0.17], P = 0.027), weight (-1.46 [-2.6 to -0.30], P = 0.015) and cognitive scores (-14.86 [-29.95 to 0.23], P = 0.05) at 2 years of age. MCA PI showed no statistically significant correlation.

CONCLUSIONS

In fetal d-TGA and HLHS, a higher UA-PI in the third trimester, suggestive of placental insufficiency-but not MCA-PI-is associated with worse 2-year growth and neurodevelopment.

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.

Maternal Predictors of Disparate Outcomes in Children With Single Ventricle Congenital Heart Disease

Background

Significant variability in morbidity and mortality persists for children with functionally single ventricle congenital heart disease (SV‐CHD) despite standardization in medical and surgical care. We hypothesized that maternal health factors may be associated with an increased risk of poor outcomes in children with SV‐CHD.

Methods and Results

This retrospective, observational, cohort study included term maternal‐infant pairs with a diagnosis of SV‐CHD who underwent surgical palliation from 2006 to 2015 at Primary Children's Hospital. Pairs lacking maternal variables of interest or infant follow‐up data were excluded. The association of maternal risk factors of abnormal pre‐pregnancy body mass index, abnormal gestational weight gain (<7 or >20 kg), hypertensive disorders, and gestational diabetes mellitus with death/transplant and hemodynamics were analyzed using regression models. Of 190 infants, 135 (71%) maternal‐infant dyads had complete data for inclusion. Death or transplant occurred in 48 infants (36%) during an average follow‐up of 2.2 years (0.1–11.7 years). Abnormal gestational weight gain was associated with an increased risk of death and/or transplant in logistic regression (odds ratio, 3.22; 95% CI, 1.32–7.86; P=0.01), but not Cox regression (hazard ratio, 1.9; 95% CI, 1.0–3.7; P=0.055). Mean pulmonary artery pressures were higher in the setting of abnormal gestational weight gain (16.5±2.9 versus 14.7±3.0 mm Hg; P<0.001), and abnormal pre‐pregnancy body mass index (15.7±3.5 versus 14.2±2.1 mm Hg; P<0.001) in the systemic right ventricle group.

Conclusions

Abnormal gestational weight gain (excessive or inadequate) is a novel risk factor for worse outcomes in SV‐CHD. The fetoplacental environment may alter the trajectory of vascular development to impact outcomes in infants with SV‐CHD.

A missense mutation of ErbB2 produces a novel mouse model of stillbirth associated with a cardiac abnormality but lacking abnormalities of placental structure

Background

In humans, stillbirth describes the death of a fetus before birth after 28 weeks gestation, and accounts for approximately 2.6 million deaths worldwide annually. In high-income countries, up to half of stillbirths have an unknown cause and are described as “unexplained stillbirths”; this lack of understanding impairs efforts to prevent stillbirth. There are also few animal models of stillbirth, but those that have been described usually have significant placental abnormalities. This study describes a novel mutant murine model of fetal death with atrial conduction block due to an ErbB2 missense mutation which is not associated with abnormal placental morphology.

Methods

Phenotypic characterisation and histological analysis of the mutant mouse model was conducted. The mRNA distribution of the early cardiomyocyte marker Nkx2-5 was assessed via in situ hybridisation. Cardiac structure was quantified and cellular morphology evaluated by electron microscopy. Immunostaining was employed to quantify placental structure and cell characteristics on matched heterozygous and homozygous mutant placental samples.

Results

There were no structural abnormalities observed in hearts of mutant embryos. Comparable Nkx2-5 expression was observed in hearts of mutants and controls, suggesting normal cardiac specification. Additionally, there was no significant difference in the weight, placenta dimensions, giant cell characteristics, labyrinth tissue composition, levels of apoptosis, proliferation or vascularisation between placentas of homozygous mutant mice and controls.

Conclusion

Embryonic lethality in the ErbB2 homozygous mutant mouse cannot be attributed to placental pathology. As such, we conclude the ErbB2^M802R mutant is a model of stillbirth with a non-placental cause of death. The mechanism of the atrial block resulting from ErbB2 mutation and its role in embryonic death is still unclear. Studying this mutant mouse model could identify candidate genes involved in stillbirth associated with structural or functional cardiac defects.