Evidence of fetal central nervous system injury in isolated congenital heart defects: microcephaly at birth

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

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

Evaluation of Intracranial Structures of Fetuses With Congenital Heart Defects

OBJECTIVES

We classified congenital heart defects (CHDs) according to cerebral blood flow oxygenation and aimed to evaluate the effect on the size of brain structures in these fetuses.

METHODS

The study which was designed retrospectively, included 28 patients with fetal CHDs and 76 patients without fetal anomalies.

RESULTS

The width and length of the cavum septum pellucidum significantly increased in the CHD group (P = .002, P = .004). The biparietal diameter and z scores were significantly lower in the single ventricle (SV) (P = .006, P = .019), and the head circumference (HC) and z scores were significantly lower in the transposition of great arteries (TGA) (P = .013, P = .038). The transverse cerebellar diameter, the cerebellar HC and the cerebellar hemisphere area values were lower in the SV (P = .005, P = .017, P = .044).

CONCLUSIONS

Brain structure changes are more pronounced in groups with low cerebral oxygenation, especially in the SV and the TGA.

Central nervous system biometry in fetuses with and without congenital heart diseases

OBJECTIVE

To compare the fetal brain structures assessed in routine sonographic scans during the second and third trimesters in fetuses with and without congenital heart disease (CHD).

METHODS

This is a retrospective cross-sectional single-center study. We measured the head circumference (HC), the transversal diameter of the cerebellum (TCD) and the sizes of the cisterna magna (CM), the cavum septi pellucidi (CSP) and the posterior ventricles (PV) between 20 and 41 weeks of gestation. We compared 160 fetuses with CHD (case group) to 160 fetuses of normal pregnancies (control group). Every patient was matched with a control, considering the gestational age at which the ultrasound was performed. We divided the CHD group into 3 subgroups: retrograde flow in the aortic arch (group 1), right heart anomaly with the antegrade flow in the aortic arch (group 2) and other CHDs with the antegrade flow in the aortic arch (group 3).

RESULTS

The mean width of the PV was larger in fetuses of groups 1 and 3 in comparison to the control group (P < 0.001, P = 0.022; respectively). We found that the APGAR score at 5 min (P < 0.001, P < 0.001; respectively) and gestational age at delivery (P = 0.006, P = 0.001; respectively) were inferior in groups 1 and 3 compared to controls.

CONCLUSIONS

Central nervous system biometry is altered in fetuses with CHD. PV is enlarged in CHD fetuses especially with decreased oxygen levels in the aortic arch.

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.

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.

The Influence of Various Cerebral and Extracerebral Pathologies on Apparent Diffusion Coefficient Values in the Fetal Brain

BACKGROUND AND PURPOSE

The changing MRI signal accompanying brain maturation in fetal brains can be quantified on apparent diffusion coefficient (ADC) maps. Deviations from the natural course of ADC values may reflect structural pathology. The purpose of this study was to determine the influence of fetal pathologies on the ADC values in different regions of the fetal brain and their evolution with increasing gestational age.

METHODS

This was a retrospective study of 291 fetuses evaluated between the 14th and the 40th week of gestation using diffusion‐weighted imaging (DWI). Fetuses with normal MRI findings but sonographically suspected pathology or fetuses with abnormalities not affecting the brain were analyzed in the control group and compared to fetuses suffering from different pathologies like hydrocephalus/ventriculomegaly, brain malformations, infections, ischemia/hemorrhage, diaphragmatic hernias, and congenital heart disease. Pairwise ADC measurements in each side of the white matter (WM) of the frontal, parietal, and occipital lobes, in the basal ganglia and the cerebellum, as well as a single measurement in the pons were performed and were plotted against gestational age.

RESULTS

In the control group, brain maturation followed a defined gradient, resulting in lower ADC values in the most mature regions. Each disorder group experienced abnormal patterns of evolution of the ADC values over time deviating from the expected course.

CONCLUSIONS

The ADC values in different regions of the fetal brain and their evolution with increasing gestational age are influenced by pathologies compromising the cerebral maturation.

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 Heart Defects and Measures of Cerebral Size

OBJECTIVES

To estimate the association between fetal congenital heart defects (CHDs) and measures of brain size throughout pregnancy, from the end of the first trimester to birth.

STUDY DESIGN

The cohort consisted of all fetuses scanned in Western Denmark in 2012 and 2013. Anthropometric measures in fetuses with isolated CHDs diagnosed within 12 months after birth were compared with those in the fetuses without CHDs. Z-scores standardized to gestational age were calculated for first trimester biparietal diameter, second trimester head circumference, fetal weight, birthweight, head circumference, and placental weight.

RESULTS

We obtained data from 63 349 pregnancies and identified 295 fetuses with isolated CHDs (major n = 145; minor n = 150). The first trimester mean biparietal diameter Z-scores were not different between those with and those without CHDs. The head circumference mean Z-score difference was -0.13 (95% CI, -0.24 to -0.01; P = .03) in the second trimester and -0.22 (95% CI, -0.35 to -0.09; P < .001) at birth. Fetuses with univentricular physiology or tetralogy of Fallot showed the most pronounced compromise in cerebral size.

CONCLUSIONS

Our results suggest that the brain alterations inducing an increased risk of impaired neurodevelopment in children with CHDs begin during pregnancy. Although fetuses with univentricular physiology or tetralogy of Fallot exhibited the most pronounced compromise in cerebral size, we recommend neurodevelopmental follow-up for all children with CHDs.

Application of the INTERGROWTH-21st chart compared to customized growth charts in fetuses with left heart obstruction: late trimester biometry, cerebroplacental hemodynamics and perinatal outcome

PURPOSE

Birth weight (BW) is crucial for surgical outcome in children with left heart obstruction (LHO). Head circumference (HC) is believed to correlate with the neurocognitive outcome in LHO. Our aim was to investigate the application of international standardized growth charts from the INTERGROWTH-21st project in comparison to customized growth charts in fetal LHO.

METHODS

This is a retrospective cohort study consisting of 60 singleton pregnancies complicated by fetal LHO. For the z score calculation of estimated fetal weight (EFW) and biometric parameters, the INTERGROWTH-21st calculator was used as well as algorithms of customized growth charts. Antenatal measurements were compared to newborn biometry and the association with fetal Doppler results (MCA PI: middle cerebral artery pulsatility index and CPR: cerebroplacental ratio) was examined. Furthermore, the ability of each antenatal chart to predict adverse perinatal outcome was evaluated.

RESULTS

At a mean gestational age of 37 weeks, all assessment charts showed significantly smaller mean values for antenatal head circumference (HC) z scores. Highest detection rate for restricted HC growth antenatally was achieved with Hadlock charts. MCA PI and CPR were not associated with neonatal HC. A significant association was observed between EFW and 1-year survival, independent of the considered growth chart.

CONCLUSIONS

Growth chart independently, antenatal HC did tend to be smaller in LHO fetuses. A significant association was observed between EFW and 1-year survival rate. Prospective investigations in CHD fetuses should be carried out with internationally standardized growth charts to better examine their prognostic value in this high-risk population.

Somatic Development in Children with Congenital Heart Defects

OBJECTIVES

Somatic development is impaired in children with congenital heart defects (CHDs), and head circumference seems to be a strong predictor of neurodevelopmental prognosis. The aim of this study was to generate up-to-date reference values for the somatic development (head circumference, body weight, and length/height) of children with CHDs.

STUDY DESIGN

Our study population consisted of all patients included in the PAN study (Prävalenz angeborener Herzfehler bei Neugeborenen in Deutschland), which was conducted prospectively over a 3-year study period by the Competence Network for Congenital Heart Defects. All children with mild, moderate, and severe CHDs born in 2006-2009 in Germany were enrolled. For computing of z-scores, only children with the following characteristics were included: appropriate for gestational age, nonsyndromic disease, term or post-term delivery, and no cardiac surgery.

RESULTS

There were 2818 patients included. New z-scores for the described somatic measures of children with mild, moderate, and severe CHDs were computed. Comparisons with the KiGGS study (Gesundheit von Kindern und Jugendlichen in Deutschland) and the Berlin Longitudinal Study revealed significantly lower measurements for all measures-most notably in children with severe CHDs and/or cardiac surgery. In our cohort, no catch-up growth was seen after cardiac surgery.

CONCLUSION

Children with severe CHDs demonstrated the most abnormal pattern in growth, including head circumference before and after cardiac surgery, which is indicative of accompanying brain pathology unrelated to operative injury.

[How to deal with a fetal head circumference lower than the third percentile?]

The prenatal finding of a head circumference (HC) below the 3rd percentile (p) remains, in the same way as short femur or increased nuchal translucency with normal karyotype, one the most difficult situations for the praticionner in the setting of prenatal diagnosis. Microcephaly is a gateway to possible cerebral pathologies, but the main objective is to identify serious prenatal situations. A standardized HC measurement, the use of adapted reference tools and charts, longitudinal following of cephalic biometrics in high-risk situations, and systematic central nervous system analysis can increase the diagnostic performance of ultrasound which is often disappointing for microcephaly. The early distinction between associated or isolated microcephaly makes it possible to quickly orient the prenatal management and counseling. Fetal MRI and genetic counseling are fundamental in this context, making it possible to specify at best the etiological diagnosis and to provide assistance to the neuropediatrician in the establishment of an often uncertain prognosis. The recent increase in cases of microcephaly concomitant with the epidemic of the ZIKA virus is an additional argument to improve our practices and the daily apprehension of HC<3rd p.

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.

Effect of congenital heart disease on 4-year neurodevelopment within multiple-gestation births

OBJECTIVES

We sought to assess the effect of congenital heart disease requiring infant surgery with cardiopulmonary bypass on neurodevelopmental outcomes and growth at 4 years of age, while matching for gestational age, socioeconomic status, maternal gestational conditions, home environment, and parental intelligence by studying multiple-gestation births.

METHODS

We performed within-family comparison of 14 multiple-gestation births in which 1 child had congenital heart disease requiring surgery with cardiopulmonary bypass at ≤6 months of age. Between 4 and 5 years of age, a comprehensive neurodevelopmental assessment was performed. Paired comparisons were conducted between siblings with and without heart defects using a series of nonparametric tests.

RESULTS

On average, the children qualified as late preterm (mean gestational age 35.4 ± 2.6 weeks). At an average age of 4.8 ± 0.1 years, children with congenital heart disease weighed less than their siblings (median weight for age z score -0.4 vs 0.1, P = .02) and had worse performance for cognition (median full-scale IQ 99 vs 109, P = .02) and fine motor skills (median Wide Range Assessment of Visual Motor Ability, Fine Motor score 94.5 vs 107.5, P < .01).

CONCLUSIONS

After controlling for socioeconomic status, home environment, parental intelligence, and gestational factors by using multiple-gestation births, congenital heart disease requiring surgery with cardiopulmonary bypass at ≤6 months of age is associated with lower weight, cognitive abilities and fine motor skills at 4 years of age.

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.

The Zika virus and pregnancy: evidence, management, and prevention

OBJECTIVE

To comprehensively review the available evidence and existing consensus reports and guidelines regarding the pregnancy and reproductive implications of the mosquito-transmitted Zika virus (ZIKV) infection. A primary focus was to provide pertinent information to aid clinicians in the management of pregnancies at risk for, exposed to, or with confirmed ZIKV infection.

METHOD

An extensive literature review was performed using Pubmed. Practice guidelines and consensus reports were accessed from international, national, and professional organizations' websites. The clinical articles for ZIKV infection testing varied from case reports to small epidemiologic studies.

RESULTS

A ZIKV epidemic has been declared in several countries in the Americas. Fifty-two travel-associated ZIKV infection cases have been reported throughout the USA (as of February 10, 2016). The consequences of congenital fetal/newborn ZIKV infection could potentially have devastating consequences including miscarriage, fetal death, and major anomalies such as microcephaly, brain and brain-stem defects, and long-term neurologic sequelae. While not definitive, current evidence suggests the existence of nonvector-borne transmission through sexual activity with an infected male partner. For women at risk for sexual transmission, condom use is advised, especially during pregnancy.

CONCLUSION

While ZIKV infection appears to be a mild disease in the general population the potential consequences to the fetus and newborn could be profound. Management guidelines are currently evolving and will be significantly impacted as new evidence develops. It is therefore imperative that obstetric health-care providers keep abreast of this rapidly evolving information landscape that has so far characterized this outbreak.

Neuropädiatrische Differenzialdiagnostik der Mikrozephalie im Kindesalter

Eine Mikrozephalie betrifft 2–3 % der Bevölkerung und geht oftmals mit einer Intelligenzminderung einher. Die zugrunde liegende Reduktion des Gehirnvolumens kann sowohl durch exogene Faktoren als auch durch genetische Ursachen bedingt sein. Problematisch sind sowohl die uneinheitliche Klassifikation als auch die große Heterogenität der hinter dem klinischen Zeichen Mikrozephalie stehenden Erkrankungen. Im vorliegenden Artikel stellen wir unseren Vorschlag für die diagnostische Herangehensweise an ein Kind mit Mikrozephalie aus neuropädiatrischer Sicht vor.

Congenital Heart Defects and Indices of Fetal Cerebral Growth in a Nationwide Cohort of 924 422 Liveborn Infants

BACKGROUND

Neurodevelopmental disorders are the most common and distressful comorbidities associated with congenital heart defects (CHD). Head circumference at birth (HC), a proxy for prenatal cerebral growth, is an established risk factor for neurodevelopmental disorders.

METHODS AND RESULTS

In a nationwide cohort, we included all 924 422 liveborn Danish singletons, 1997 to 2011. CHD was present in 5519. The association between CHD and growth indices was analyzed by multivariable linear regression, adjusted for potential confounders. We report mean differences in gestational age-specific z scores in comparison with the general population. CHD was associated with lower HC z scores, -0.10 (95% confidence interval [CI], -0.13 to -0.08). Several CHD subtypes were associated with smaller HC, eg, hypoplastic left heart syndrome, -0.39 (95% CI, -0.58 to -0.21); common arterial trunk, -0.41 (95% CI, -0.74 to -0.09); and major ventricular septal defects, -0.25 (95% CI, -0.35 to -0.15). Other single-ventricle defects, transposition of the great arteries, tetralogy of Fallot, and anomalous pulmonary venous return, were also associated with smaller HC. Transposition of the great arteries was associated with smaller HC relative to birth weight, -0.26 (95% CI, -0.39 to -0.13). Major ventricular septal defects were associated with larger HC relative to birth weight. The results were consistent under various conditions, eg, when siblings of infants with CHD (n=5311) or infants with other major malformations (n=24 974) were used as the reference.

CONCLUSIONS

Several subtypes of CHD were associated with smaller HC. The associations with major ventricular septal defects, common arterial trunk, and anomalous pulmonary venous return have not previously been described. Only infants with transposition of the great arteries had smaller HC relative to birth weight.

Fetal MRI detects early alterations of brain development in Tetralogy of Fallot

OBJECTIVE

Prenatal imaging has identified alterations of brain growth in fetuses with congenital heart disease. However, little is known about the timing of altered brain development and its occurrence in specific congenital heart disease subgroups. This magnetic resonance imaging study aimed to identify early (median, 25 gestational weeks [GW]) changes in fetal total brain (TBV), gray matter (GMV), and subcortical brain (SBV) volumes in Tetralogy of Fallot (TOF) cases in utero.

STUDY DESIGN

Fetal magnetic resonance imaging (1.5 Tesla) was performed in 24 fetuses who were diagnosed with TOF and 24 normal age-matched control fetuses (20-34 GW). TBV, GMV, SBV, intracranial cavity, cerebellar, ventricular, and external cerebrospinal fluid volumes were quantified by manual segmentation based on coronal T2-weighted sequences. Mixed model analyses of variance and t-tests were conducted to compare cases and control fetuses.

RESULTS

TBV was significantly lower (P < .001) in early (<25 GW) and late TOF cases. Both GMV (P = .003) and SBV (P = .001) were affected. The GMV-to-SBV ratio declined in fetuses with TOF (P = .026). Compared with normal fetuses, ventricular volume was increased (P = .0048). External cerebrospinal fluid was enlarged in relation to head size (P < .001). Intracranial cavity volume (P = .314) and cerebellar volume (P = .074) were not significantly reduced in fetuses with TOF.

CONCLUSION

TOF is associated with smaller volumes of gray and white matter and enlarged cerebrospinal fluid spaces. These changes are present at ≤25 GW and indicate altered fetal brain growth in this pathophysiologic entity during early stages of human brain development.

Oxygen supply to the fetal cerebral circulation in hypoplastic left heart syndrome: a simulation study based on the theoretical models of fetal circulation

Hypoxia due to congenital heart diseases (CHDs) adversely affects brain development during the fetal period. Head circumference at birth is closely associated with neuropsychiatric development, and it is considerably smaller in newborns with hypoplastic left heart syndrome (HLHS) than in normal newborns. We performed simulation studies on newborns with CHD to evaluate the cerebral circulation during the fetal period. The oxygen saturation of cerebral blood flow in newborns with CHD was simulated according to a model for normal fetal circulation in late pregnancy. We compared the oxygen saturation of cerebral blood flow between newborns with tricuspid atresia (TA; a disease showing univentricular circulation and hypoplasia of the right ventricle), those with transposition of the great arteries (TGA; a disease showing abnormal mixing of arterial and venous blood), and those with HLHS. The oxygen saturation of cerebral blood flow in newborns with normal circulation was 75.7 %, whereas it was low (49.5 %) in both newborns with HLHS and those with TA. Although the oxygen level is affected by the blood flow through the foramen ovale, the oxygen saturation in newborns with TGA was even lower (43.2 %). These data, together with previous reports, suggest that the cerebral blood flow rate is decreased in newborns with HLHS, and the main cause was strongly suspected to be retrograde cerebral perfusion through a patent ductus arteriosus. This study provides important information about the neurodevelopmental prognosis of newborns with HLHS and suggests the need to identify strategies to resolve this unfavorable cerebral circulatory state in utero.

Pre-operative renal volume predicts peak creatinine after congenital heart surgery in neonates

OBJECTIVE

Acute kidney injury is common in neonates following surgery for congenital heart disease. We conducted a retrospective analysis to determine whether neonates with smaller pre-operative renal volume were more likely to develop post-operative acute kidney injury.

DESIGN/SETTING

We conducted a retrospective review of 72 neonates who underwent congenital heart surgery for any lesion other than patent ductus arteriosus at our institution from January 2007 to December 2011. Renal volume was calculated by ultrasound using the prolate ellipsoid formula. The presence and severity of post-operative acute kidney injury was determined both by measuring the peak serum creatinine in the first 7 days post-operatively and by using the Acute Kidney Injury Network scoring system.

RESULTS

Using a linear change point model, a threshold renal volume of 17 cm³ was identified. Below this threshold, there was an inverse linear relationship between renal volume and peak post-operative creatinine for all patients (p = 0.036) and the subgroup with a single morphologic right ventricle (p = 0.046). There was a non-significant trend towards more acute kidney injury using Acute Kidney Injury Network criteria in all neonates with renal volume ≤17 cm³ (p = 0.11) and in the subgroup with a single morphologic right ventricle (p = 0.17).

CONCLUSIONS

Pre-operative renal volume ≤17 cm³ is associated with a higher peak post-operative creatinine and potentially greater risk for post-operative acute kidney injury for neonates undergoing congenital heart surgery. Neonates with a single right ventricle may be at higher risk.

Somatic growth trajectory in the fetus with hypoplastic left heart syndrome

BACKGROUND

Fetal growth abnormalities in hypoplastic left heart syndrome (HLHS) have been documented primarily by birth measurements. Fetal growth trajectory has not been described. We hypothesized that fetal growth trajectory declines across late gestation in this population.

METHODS

Infants with a prenatal diagnosis of HLHS and no history of prematurity or a genetic syndrome were identified. Fetal ultrasound measurements and birth anthropometrics were obtained from clinical records. z-Scores for estimated fetal weight (EFWz) and birth weight (BWTz) were compared. BWTz for three neonatal standards were compared.

RESULTS

Paired fetal and neonatal data were identified in 33 cases of HLHS. Mean gestational age at ultrasound and birth were 27 and 38 wk, respectively. BWTz was lower than EFWz by a mean of 0.82 (SD: 0.72, P < 0.0001), with 64% of subjects demonstrating a decrease in z-score of >0.5. Umbilical artery (UA) Doppler found no evidence of significant placental insufficiency. Modest differences in BWTz were seen across BWT standards in this cohort.

CONCLUSION

The majority of fetuses with HLHS demonstrate decreased growth velocity during later pregnancy, suggesting growth abnormalities manifest in utero. The potential relationship to future clinical outcomes warrants further study.

Abnormal brain structure and function in newborns with complex congenital heart defects before open heart surgery: a review of the evidence

Newborns with complex congenital heart defects are at high risk for developing neurological abnormalities. It is important to understand the timing, progression, and extent of these abnormalities to better elucidate their potential impact on neurodevelopment, and their implications for early screening and intervention. This review synthesizes the recent literature describing neurological and neurobehavioral abnormalities observed in fetuses and newborns before cardiac surgery. A considerable proportion of newborns with complex congenital heart defects exhibit neurobehavioral and electrophysiological abnormalities preoperatively. Likewise, conventional neuroimaging studies reported that a high percentage of this population experienced brain injury. Advanced neuroimaging modalities indicated that fetuses showed delayed third trimester brain growth, and newborns showed impaired white matter maturation, reduced N-acetylaspartate, and increased lactate. These findings suggest a fetal or early postnatal onset of impaired brain growth and development. Consequently, reliable methods for early screening and subsequent developmental intervention must be implemented.

Fetal cerebral blood flow velocities in congenital diaphragmatic hernia

OBJECTIVES

Left ventricular cardiac output is decreased in fetuses with congenital diaphragmatic hernia (CDH). Our aim was to assess whether this alters cerebral perfusion or growth in utero.

METHODS

Fetal head circumference, biparietal diameter, lung-to-head ratio and middle cerebral artery (MCA) Doppler flow patterns were assessed by ultrasonography in 103 fetuses with prenatally diagnosed CDH. Total fetal lung volume and cerebral volume were measured using magnetic resonance imaging. Values were transformed to gestational age-independent scores (multiples of the median (MoM)) and compared with controls. Subanalyses were made according to whether the CDH was left- (n = 86) or right-sided (n = 17) and to whether it was isolated (n = 86) or associated with other anomalies (n = 17).

RESULTS

MCA flow velocity was significantly lower in fetuses with CDH than in healthy fetuses (0.79 ± 0.19 MoM; P < 0.0001) but MCA pulsatility index was unchanged (0.99 ± 0.25 MoM; P = 0.79). Cranial biometry and cerebral volume in CDH fetuses fell in the normal range. Gestational age-adjusted lung area was correlated with MCA peak systolic velocity, which was in turn correlated with brain volume.

CONCLUSIONS

Fetal cerebral blood flow velocities are decreased in CDH yet cranial and cerebral growth are conserved. Further work will be needed to address whether part of the neurologic impairment observed in long-term survivors of CDH finds its origin in the prenatal period.

Doppler indices of the middle cerebral artery in fetuses with cardiac defects theoretically associated with impaired cerebral oxygen delivery in utero: is there a brain-sparing effect?

OBJECTIVES

To assess changes in the Doppler flow profiles of the middle cerebral artery in fetuses with cardiac defects theoretically associated with impaired cerebral oxygen delivery in utero.

METHODS

Z-scores were calculated for pulsatility and resistance indices (PI and RI, respectively) of the middle cerebral artery (MCA) and the cerebroplacental ratio (CPR) between 19 and 41 weeks' gestation, and for head circumference at birth (HC), in 113 fetuses with the following isolated cardiac defects: transposition of the great arteries (TGA; n = 18), hypoplastic left heart (HLH; n = 46), severe aortic stenosis (n = 17), pulmonary atresia (n = 18) and tetralogy of Fallot (TOF; n = 14). Pregnancies with uteroplacental dysfunction (indicated by increased uterine and/or umbilical Doppler indices), growth restriction, extracardiac malformations, chromosomal anomalies as well as multiple pregnancies were excluded to avoid any additional hypoxemic effect as strictly as possible. The results were compared with 1378 normal controls.

RESULTS

Fetuses with pulmonary atresia, severe aortic stenosis and TOF had no significant alterations of Doppler parameters or HC at birth. In fetuses with TGA, mean Z-scores of HC at birth were significantly smaller compared with controls (mean +/- SD, -0.73 +/- 1.25; P < 0.05), but there was no significant difference in the Doppler parameters. Fetuses with HLH had significantly lower MCA-PI (-0.57 +/- 0.74; P < 0.05), MCA-RI (-0.73 +/- 0.85; P < 0.05), CPR (-1.44 +/- 1.05; P < 0.05) and HC (-0.50 +/- 1.24; P < 0.05) Z-scores compared with controls.

CONCLUSIONS

Fetuses with cardiac defects theoretically associated with markedly impaired cerebral oxygen delivery in utero (TGA and HLH) have smaller HCs at birth. However, only fetuses with HLH have cerebrovascular alterations that are detectable by evaluation of the Doppler indices MCA-PI, MCA-RI and CPR.