Mid-gestation brain Doppler and head biometry in fetuses with congenital heart disease predict abnormal brain development at birth

Foetal cortical expansion is associated with neurodevelopmental outcome at 2-years in congenital heart disease: a longitudinal follow-up study

BACKGROUND

In adolescents and adults with complex congenital heart disease (CHD), abnormal cortical folding is a putative predictor of poor neurodevelopmental outcome. However, it is unknown when this relationship first emerges. We test the hypothesis that it begins in utero, when the brain starts to gyrify and folding patterns first become established.

METHODS

We carried out a prospective, longitudinal case-control study, acquiring foetal MRIs at two timepoints in utero, (Scan 1 = 20-30 Gestational Weeks (GW) and Scan 2 = 30-39 GW), then followed up participants at two years of age to assess neurodevelopmental outcomes. We used normative modelling to chart growth trajectories of surface features across 60 cortical regions in a control population (n = 157), then quantified the deviance of each foetus with CHD (n = 135) and explored the association with neurodevelopmental outcomes at two years of age.

FINDINGS

Differences in cortical development between CHD and Control foetuses only emerged after 30 GW, and lower regional cortical surface area growth was correlated with poorer neurodevelopmental outcomes at two years of age in the CHD group.

INTERPRETATION

This work highlights the third trimester specifically as a critical period in brain development for foetuses with CHD, where the reduced surface area expansion in specific cortical regions becomes consequential in later life, and predictive of neurodevelopmental outcome in toddlerhood.

FUNDING

This research was supported by the NINDS (R01NS114087, K23NS101120) and NIBIB (R01EB031170) of the NIH, PHN Scholar Award, AAN Clinical Research Training Fellowship, BBRF Young Investigator Awards, and the Farb Family Fund.

Structural Covariance Networks in the Fetal Brain Reveal Altered Neurodevelopment for Specific Subtypes of Congenital Heart Disease

BACKGROUND

Altered structural brain development has been identified in fetuses with congenital heart disease (CHD), suggesting that the neurodevelopmental impairment observed later in life might originate in utero. There are many interacting factors that may perturb neurodevelopment during the fetal period and manifest as structural brain alterations, such as altered cerebral substrate delivery and aberrant fetal hemodynamics.

METHODS AND RESULTS

We extracted structural covariance networks from the log Jacobian determinants of 435 in utero T2 weighted image magnetic resonance imaging scans, (n=67 controls, 368 with CHD) acquired during the third trimester. We fit general linear models to test whether age, sex, expected cerebral substrate delivery, and CHD diagnosis were significant predictors of structural covariance. We identified significant effects of age, sex, cerebral substrate delivery, and specific CHD diagnosis across a variety of structural covariance networks, including primary motor and sensory cortices, cerebellar regions, frontal cortex, extra-axial cerebrospinal fluid, thalamus, brainstem, and insula, consistent with widespread coordinated aberrant maturation of specific brain regions over the third trimester.

CONCLUSIONS

Structural covariance networks offer a sensitive, data-driven approach to explore whole-brain structural changes without anatomical priors. We used them to stratify a heterogenous patient cohort with CHD, highlighting similarities and differences between diagnoses during fetal neurodevelopment. Although there was a clear effect of abnormal fetal hemodynamics on structural brain maturation, our results suggest that this alone does not explain all the variation in brain development between individuals with CHD.

Continuous Electroencephalogram (cEEG) Findings and Neurodevelopmental Outcomes in Neonates with Congenital Heart Disease (CHD) at 12-24 Months of Age

OBJECTIVE

This study aims to assess the role of continuous EEG (cEEG) background patterns and duration of cross-clamp time and cardiopulmonary bypass (CPB) in children with congenital heart disease (CHD) undergoing cardiac surgery and its correlation with abnormal neurodevelopmental outcomes at 12-24 months on Bayley Scales of Infant and Toddler Development (BSID-III).

METHODS

This retrospective cohort study included infants with CHD and cEEG monitoring, who underwent surgery by 44 weeks gestational age.

RESULTS

34 patients were included, who were operated at median age - 7 days. Longer duration of cross- camp time was associated with poor language composite scores (LCS) (p value = 0.036). A significant association existed between severity of encephalopathy in 24-hour post-operative period and poor LCS (p value = 0.026).

CONCLUSION

Majority of neonates with CHD have below average cognitive, language and motor composite scores on BSID-III. Longer duration of cross-clamp time and severity of encephalopathy during 24-hour post-operative EEG monitoring are associated with poor LCS.

A role for immunohistochemical stains in perinatal brain autopsies

Identification of central nervous system injury is a critical part of perinatal autopsies; however, injury is not always easily identifiable due to autolysis and immaturity of the developing brain. Here, the role of immunohistochemical stains in the identification of perinatal brain injury was investigated. Blinded semiquantitative scoring of injury was performed on sections of frontal lobe from 76 cases (51 liveborn and 25 stillborn) using H&E, GFAP, Iba-1, and β-APP stains. Digital image analysis was used to quantify GFAP and Iba-1 staining. Commonly observed pathologies included diffuse white matter gliosis (DWMG) and white matter necrosis (WMN). DWMG scores were very similar on H&E and GFAP stains for liveborn subjects. For stillborn subjects, DWMG scores were significantly higher on GFAP stain than H&E. β-APP was needed for identification of WMN in 71.4% of stillborn subjects compared to 15.4% of liveborn subjects. Diffuse staining for Iba-1 within cortex and white matter was positively correlated with subject age. Staining quantification on digital image analysis was highly correlated to semiquantitative scoring. Overall, GFAP and β-APP stains were most helpful in identifying white matter injury not seen on H&E in stillborn subjects. Immunostains may therefore be warranted as an integral part of stillborn brain autopsies.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Magnetic Resonance Spectroscopy of Brain Metabolism in Fetuses With Congenital Heart Disease

BACKGROUND

Congenital heart disease (CHD) remains a significant risk factor for neurologic injury because altered fetal hemodynamics may be unable to support typical brain development during critical periods of growth and maturation.

OBJECTIVES

The primary objective was to assess differences in the cerebral biochemical profile between healthy fetuses and fetuses with complex CHD and to relate these with infant outcomes.

METHODS

Pregnant participants underwent fetal magnetic resonance imaging with cerebral proton magnetic resonance spectroscopy acquisitions as part of a prospective observational study. Cerebral metabolites of N-acetyl aspartate, creatine, choline, myo-inositol, scyllo-inositol, lactate, and relevant ratios were quantified using LCModel.

RESULTS

We acquired 503 proton magnetic resonance spectroscopy images (controls = 333; CHD = 170) from 333 participants (controls = 221; CHD = 112). Mean choline levels were higher in CHD compared with controls (CHD 2.47 IU [Institutional Units] ± 0.44 and Controls 2.35 IU ± 0.45; P = 0.02), whereas N-acetyl aspartate:choline ratios were lower among CHD fetuses compared with controls (CHD 1.34 ± 0.40 IU vs controls 1.44 ± 0.48 IU; P = 0.001). Cerebral lactate was detected in all cohorts but increased in fetuses with transposition of the great arteries and single-ventricle CHD (median: 1.63 [IQR: 0.56-3.27] in transposition of the great arteries and median: 1.28 [IQR: 0-2.42] in single-ventricle CHD) compared with 2-ventricle CHD (median: 0.79 [IQR: 0-1.45]). Cerebral lactate also was associated with increased odds of death before discharge (OR: 1.75; P = 0.04).

CONCLUSIONS

CHD is associated with altered cerebral metabolites in utero, particularly in the third trimester period of pregnancy, which is characterized by exponential brain growth and maturation, and is associated with survival to hospital discharge. The long-term neurodevelopmental consequences of these findings warrant further study.

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.

Fetal MRI of the heart and brain in congenital heart disease

Antenatal assessment of congenital heart disease and associated anomalies by ultrasound has improved perinatal care. Fetal cardiovascular MRI and fetal brain MRI are rapidly evolving for fetal diagnostic testing of congenital heart disease. We give an overview on the use of fetal cardiovascular MRI and fetal brain MRI in congenital heart disease, focusing on the current applications and diagnostic yield of structural and functional imaging during pregnancy. Fetal cardiovascular MRI in congenital heart disease is a promising supplementary imaging method to echocardiography for the diagnosis of antenatal congenital heart disease in weeks 30-40 of pregnancy. Concomitant fetal brain MRI is superior to brain ultrasound to show the complex relationship between fetal haemodynamics in congenital heart disease and brain development.

Neuroimaging and Cerebrovascular Changes in Fetuses with Complex Congenital Heart Disease

Background: Congenital heart diseases (CHDs) are often associated with significant neurocognitive impairment and neurological delay. This study aims to elucidate the correlation between type of CHD and Doppler velocimetry and to investigate the possible presence of fetal brain abnormalities identified by magnetic resonance imaging (MRI). Methods: From July 2010 to July 2020, we carried out a cross-sectional study of 63 singleton pregnancies with a diagnosis of different types of complex CHD: LSOL (left-sided obstructive lesions; RSOL (right-sided obstructive lesions) and MTC (mixed type of CHD). All patients underwent fetal echocardiography, ultrasound evaluation, a magnetic resonance of the fetal brain, and genetic counseling. Results: The analysis of 63 fetuses shows statistically significant results in Doppler velocimetry among the different CHD groups. The RSOL group leads to higher umbilical artery (UA-PI) pressure indexes values, whereas the LSOL group correlates with significantly lower values of the middle cerebral artery (MCA-PI) compared to the other subgroups (p = 0.036), whereas the RSOL group shows a tendency to higher pulsatility indexes in the umbilical artery (UA-PI). A significant correlation has been found between a reduced head circumference (HC) and the presence of brain injury at MRI (p = 0.003). Conclusions: Congenital left- and right-sided cardiac obstructive lesions are responsible for fetal hemodynamic changes and brain growth impairment. The correct evaluation of the central nervous system (CNS) in fetuses affected by CHD could be essential as prenatal screening and the prediction of postnatal abnormalities.

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.

Impact of Congenital Heart Defects on the Developing Brain

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Longitudinal changes in fetal head biometry and fetoplacental circulation in fetuses with congenital heart defects

INTRODUCTION

Objectives were to analyze changes in fetal cephalic biometry and fetoplacental circulation throughout pregnancy in fetuses with congenital heart defects.

MATERIAL AND METHODS

Prospective study conducted on three university tertiary referral hospitals. Fetuses with the diagnosis of isolated congenital heart defects attending between 2014 and 2018 were included. Congenital heart defects were divided into two groups according to the oxygen supply to the central nervous system: group I (expected low placental blood content and low oxygen delivery to the brain) and group II (expected intermediate and high placental blood content). Fetal biometry and Doppler parameters were collected between 25-30 weeks of gestation and 34-40 weeks of gestation and transformed into Z scores. The results were compared with healthy controls. Finally, general linear modeling was performed to analyze repeated measurements.

RESULTS

In all, 71 fetuses met the inclusion criteria. Fetuses with congenital heart defects had significantly smaller head (biparietal diameter [p < 0.001], head circumference [p = 0.001]) and abdominal circumference (p < 0.001), and lower estimated fetal weight (p < 0.001) than controls. When analyzing according to congenital heart defects type, head size was significantly smaller in group I compared with group II (p = 0.04). Regarding Doppler parameters, fetuses with congenital heart defects showed higher umbilical artery pulsatility index (p < 0.001) and lower cerebroplacental ratio (p = 0.044) than controls. In group I, umbilical artery pulsatility index was above the 95th centile in 15.4% of fetuses compared with 6.7% in group II and 1.9% in controls (p < 0.001); moreover, middle cerebral artery pulsatility index was below the 5th centile in 5.4% of group I fetuses compared with 0% in group II and 1.2% in controls (p = 0.011). General linear model for two measurements showed significant longitudinal changes in biometric parameters. Growth rate of fetal head through pregnancy (head circumference Z score) was lower in fetuses with congenital heart defects compared with controls (p = 0.043). In group I, the head circumference Z score longitudinal decrease was significantly higher than in group II (p < 0.001).

CONCLUSIONS

Fetuses with congenital heart defects are at risk of smaller head size and Doppler changes. Growth rate of fetal head throughout pregnancy is also affected. These findings are mainly associated with cardiac defects with expected low oxygen supply to the central nervous system.

In Utero MRI Identifies Impaired Second Trimester Subplate Growth in Fetuses with Congenital Heart Disease

The subplate is a transient brain structure which plays a key role in the maturation of the cerebral cortex. Altered brain growth and cortical development have been suggested in fetuses with complex congenital heart disease (CHD) in the third trimester. However, at an earlier gestation, the putative role of the subplate in altered brain development in CHD fetuses is poorly understood. This study aims to examine subplate growth (i.e., volume and thickness) and its relationship to cortical sulcal development in CHD fetuses compared with healthy fetuses by using 3D reconstructed fetal magnetic resonance imaging. We studied 260 fetuses, including 100 CHD fetuses (22.3-32 gestational weeks) and 160 healthy fetuses (19.6-31.9 gestational weeks). Compared with healthy fetuses, CHD fetuses had 1) decreased global and regional subplate volumes and 2) decreased subplate thickness in the right hemisphere overall, in frontal and temporal lobes, and insula. Compared with fetuses with two-ventricle CHD, those with single-ventricle CHD had reduced subplate volume and thickness in right occipital and temporal lobes. Finally, impaired subplate growth was associated with disturbances in cortical sulcal development in CHD fetuses. These findings suggested a potential mechanistic pathway and early biomarker for the third-trimester failure of brain development in fetuses with complex CHD.

SIGNIFICANCE STATEMENT

Our findings provide an early biomarker for brain maturational failure in fetuses with congenital heart disease, which may guide the development of future prenatal interventions aimed at reducing neurological compromise of prenatal origin in this high-risk population.

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.

Brainstem and cerebellar volumes at magnetic resonance imaging are smaller in fetuses with congenital heart disease

BACKGROUND

Congenital heart disease is associated with an increased risk of smaller brain volumes and structural brain damage, and impaired growth of supratentorial brain structures in utero has been linked to poor neurodevelopmental outcomes. However, little is known on brainstem and cerebellar volumes in fetuses with congenital heart disease. Moreover, it is not clear whether impaired infratentorial growth, if present, is associated with only certain types of fetal cardiac defects or with supratentorial brain growth, and whether altered biometry is already present before the third trimester.

OBJECTIVE

This study aimed to investigate brainstem and cerebellar volumes in fetuses with congenital heart disease and to compare them to infratentorial brain volumes in fetuses with normal hearts. Secondarily, the study aimed to identify associations between infratentorial brain biometry and the type of cardiac defects, supratentorial brain volumes, and gestational age.

STUDY DESIGN

In this retrospective case-control study, 141 magnetic resonance imaging studies of 135 fetuses with congenital heart disease and 141 magnetic resonance imaging studies of 125 controls with normal hearts at 20 to 37 gestational weeks (median, 25 weeks) were evaluated. All cases and controls had normal birthweight and no evidence of structural brain disease or genetic syndrome. Six types of congenital heart disease were included: tetralogy of Fallot (n=32); double-outlet right ventricle (n=22); transposition of the great arteries (n=27); aortic obstruction (n=24); hypoplastic left heart syndrome (n=22); and hypoplastic right heart syndrome (n=14). First, brainstem and cerebellar volumes of each fetus were segmented and compared between cases and controls. In addition, transverse cerebellar diameters, vermian areas, and supratentorial brain and cerebrospinal fluid volumes were quantified and differences assessed between cases and controls. Volumetric differences were further analyzed according to types of cardiac defects and supratentorial brain volumes. Finally, volume ratios were created for each brain structure ([volume in fetus with congenital heart disease/respective volume in control fetus] × 100) and correlated to gestational age.

RESULTS

Brainstem (cases, 2.1 cm³ vs controls, 2.4 cm³; P<.001) and cerebellar (cases, 3.2 cm³ vs controls, 3.4 cm³; P<.001) volumes were smaller in fetuses with congenital heart disease than in controls, whereas transverse cerebellar diameters (P=.681) and vermian areas (P=.947) did not differ between groups. Brainstem and cerebellar volumes differed between types of cardiac defects. Overall, the volume ratio of cases to controls was 80.8% for the brainstem, 90.5% for the cerebellum, and 90.1% for the supratentorial brain. Fetuses with tetralogy of Fallot and transposition of the great arteries were most severely affected by total brain volume reduction. Gestational age had no effect on volume ratios.

CONCLUSION

The volume of the infratentorial brain, which contains structures considered crucial to brain function, is significantly smaller in fetuses with congenital heart disease than in controls from midgestation onward. These findings suggest that impaired growth of both supra- and infratentorial brain structures in fetuses with congenital heart disease occurs in the second trimester. Further research is needed to elucidate associations between fetal brain volumes and neurodevelopmental outcomes in congenital heart disease.

Contribution of fetal magnetic resonance imaging in fetuses with congenital heart disease

BACKGROUND

Increasing evidence supports an association among congenital heart disease (CHD), structural brain lesions on neuroimaging, and increased risk of neurodevelopmental delay and other structural anomalies. Fetal MRI has been found to be effective in demonstrating fetal structural and developmental abnormalities.

OBJECTIVE

To determine the contribution of fetal MRI to identifying cardiovascular and non-cardiovascular anomalies in fetuses with CHD compared to prenatal US and fetal echocardiography.

MATERIALS AND METHODS

We performed a retrospective study of fetuses with CHD identified by fetal echocardiography. Exams were performed on 1.5-tesla (T) or 3-T magnets using a balanced turbo field echo sequence triggered by an external electrocardiogram simulator with a fixed heart rate of 140 beats per minute (bpm). Fetal echocardiography was performed by pediatric cardiologists and detailed obstetrical US by maternal-fetal medicine specialists prior to referral to MRI. We compared the sensitivity of fetal MRI and fetal echocardiography for the diagnosis of cardiovascular anomalies, as well as the sensitivity of fetal MRI and referral US for the diagnosis of non-cardiac anomalies. We performed statistical analysis using the McNemar test.

RESULTS

We identified 121 anomalies in 31 fetuses. Of these, 73 (60.3%) were cardiovascular and 48 (39.7%) involved other organ systems. Fetal echocardiography was more sensitive for diagnosing cardiovascular anomalies compared to fetal MRI, but the difference was not statistically significant (85.9%, 95% confidence interval [CI] 77.8-94.0% vs. 77.5%, 95% CI 67.7-87.2%, respectively; McNemar test 2.29; P=0.13). The sensitivity of fetal MRI was higher for diagnosing extracardiac anomalies when compared to referral US (84.1%, 95% CI 73.3-94.9% vs. 31.8%, 95% CI 18.1-45.6%, respectively; McNemar test 12.9; P<0.001). The additional information provided by fetal MRI changed prognosis, counseling or management for 10/31 fetuses (32.2%), all in the group of 19 fetuses with anomalies in other organs and systems besides CHD.

CONCLUSION

Fetal MRI performed in a population of fetuses with CHD provided additional information that altered prognosis, counseling or management in approximately one-third of the fetuses, mainly by identifying previously unknown anomalies in other organs and systems.

Corpus callosum size by neurosonography in fetuses with congenital heart defect and relationship with expected pattern of brain oxygen supply

OBJECTIVE

To evaluate corpus callosum (CC) size by neurosonography (NSG) in fetuses with an isolated major congenital heart defect (CHD) and explore the association of CC size with the expected pattern of in-utero oxygen supply to the brain.

METHODS

A total of 56 fetuses with postnatally confirmed isolated major CHD and 56 gestational-age-matched controls were included. Fetuses with CHD were stratified into two categories according to the main expected pattern of cerebral arterial oxygen supply: Class A, moderately to severely reduced oxygen supply (left outflow tract obstruction and transposition of the great arteries) and Class B, near normal or mildly impaired oxygenated blood supply to the brain (other CHD). Transvaginal NSG was performed at 32-36 weeks in all fetuses to evaluate CC length, CC total area and areas of CC subdivisions in the midsagittal plane.

RESULTS

CHD fetuses had a significantly smaller CC area as compared to controls (7.91 ± 1.30 vs 9.01 ± 1.44 mm² ; P < 0.001), which was more pronounced in the most posterior part of the CC. There was a significant linear trend for reduced CC total area across the three clinical groups, with CHD Class-A cases showing more prominent changes (controls, 9.01 ± 1.44 vs CHD Class B, 8.18 ± 1.21 vs CHD Class A, 7.53 ± 1.33 mm² ; P < 0.05).

CONCLUSIONS

Fetuses with major CHD had a smaller CC compared with controls, and the difference was more marked in the CHD subgroup with expected poorer brain oxygenation. Sonographic CC size could be a clinically feasible marker of abnormal white matter development in CHD. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Brain Oxygen Perfusion and Oxidative Stress Biomarkers in Fetuses with Congenital Heart Disease - A Retrospective, Case-Control Pilot Study

Fetuses with congenital heart disease (CHD) have circulatory changes that may lead to predictable blood flow disturbances that may affect normal brain development. Hypoxemia and hypoperfusion may alter the redox balance leading to oxidative stress (OS), that can be assessed measuring stable end-products. OS biomarkers (OSB) were measured in amniotic fluid in fetuses with (n = 41) and without CHD (n = 44) and analyzed according to aortic flow, expected cyanosis after birth, and a CHD classification derived from this. Birth head circumference (HC) was used as a neurodevelopment biomarker. CHD fetuses had higher levels of ortho-Tyrosine (o-Tyr) than controls (p = 0.0003). There were no differences in o-Tyr levels considering aortic flow obstruction (p = 0.617). Fetuses with expected extreme cyanosis presented the highest levels of o-Tyr (p = 0.003). Among groups of CHD, fetuses without aortic obstruction and extreme cyanosis had the highest levels of o-Tyr (p = 0.005). CHD patients had lower HC than controls (p = 0.023), without correlation with OSB. Patients with HC < 10th percentile, presented high levels of o-Tyr (p = 0.024). Fetuses with CHD showed increased OSB and lower HC when compared to controls, especially those with expected extreme cyanosis. Our results suggest that increased levels of OSB are more influenced by the effect of low oxygenation than by aortic flow obstruction. Future studies with larger sample size are needed to further investigate the role of OSB as an early predictor of neurodevelopmental problems in CHD survivors.

Survival, Morbidities, and Developmental Outcomes among Low Birth Weight Infants with Congenital Heart Defects

OBJECTIVE

Prematurity and low birth weight (LBW) are risk factors for increased morbidity and mortality in infants with congenital heart defects (CHDs). We sought to describe survival, inhospital morbidities, and 2-year neurodevelopmental follow-up in LBW infants with CHD.

STUDY DESIGN

We included infants with birth weight (BW) <2,500 g diagnosed with CHD (except isolated patent ductus arteriosus) admitted January 2013 to March 2016 to a single level-IV academic neonatal intensive care unit. We reported CHD prevalence by BW and gestational age; selected in-hospital morbidities and mortality by infant BW, CHD type, and surgical intervention; and developmental outcomes by Bayley's scales of infant and toddler development, third edition (BSID-III) scores at age 2 years.

RESULTS

Among 420 infants with CHD, 28 (7%) underwent cardiac surgery. Median (25th and 75th percentiles) gestational age was 30 (range: 27-33) weeks and BW was 1,258 (range: 870-1,853) g. There were 134 of 420 (32%) extremely LBW (<1,000 g) infants, 82 of 420 (20%) were small for gestational age, and 51 of 420 (12%) multiples. Most common diagnosis: atrial septal defect (260/420, 62%), followed by congenital anomaly of the pulmonary valve (75/420, 18%). Most common surgical procedure: pulmonary artery banding (5/28, 18%), followed by the tetralogy of Fallot corrective repair (4/28, 14%). Survival to discharge was 88% overall and lower among extremely LBW (<1,000 g, 81%) infants and infants undergoing surgery (79%). Comorbidities were common (35%); retinopathy of prematurity and bronchopulmonary dysplasia were most prevalent. BSID-III scores were available on 148 of 176 (84%); any scores <85 were noted in 73 of 148 (49%), with language being most commonly affected.

CONCLUSION

Among LBW infants with congenital heart disease, hospital mortality varied by BW and cardiac diagnosis.

KEY POINTS

· In low birth weight infants with congenital heart disease, survival varied by birth weight and cardiac diagnosis.. · Overall survival was higher than previously reported.. · There were fewer morbidities than previously reported.. · Bayley's scale-III scores at 2 years of age were <85 for nearly half..

Serial neurosonography in fetuses with congenital heart defects shows mild delays in cortical development

INTRODUCTION

Neurodevelopmental delay is more common in children born with congenital heart defects (CHD), even with optimal perinatal and peri-operative care. It is hypothesized that fetuses with CHD are prone to neurological impairment in utero due to their cardiac defect, possibly leading to delayed cortical development.

METHODS

Cerebral cortical maturation was assessed with advanced neurosonographic examinations every 4 weeks in fetuses with CHD and compared to control fetuses. Five different primary fissures and four areas were scored (ranging 0-5) by blinded examiners using a cortical maturation scheme.

RESULTS

Cortical staging was assessed in 574 ultrasound examinations in 85 CHD fetuses and 61 controls. Small differences in grading were seen in Sylvian and cingulate fissures. (Sylvian fissure: -0.12 grade, 95% CI (-0.23; -0.01) p = 0.05, cingulate fissure: -0.24 grade, 95% CI (-0.38; -0.10) p = <0.001. Other cortical areas showed normal maturation as compared to control fetuses.

CONCLUSION

Small differences were seen in three of the nine analyzed cortical areas in CHD fetuses, in contrast to previous reports on progressive third-trimester delay. The clinical implications of the small differences however, remain unknown.

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.

MRI studies of brain size and growth in individuals with congenital heart disease

Congenital heart disease (CHD) is the most frequent congenital abnormality. Most infants born with CHD now survive. However, survivors of CHD are at increased risk of neurodevelopmental impairment, which may be due to impaired brain development in the fetal and neonatal period. Magnetic resonance imaging (MRI) provides objective measures of brain volume and growth. Here, we review MRI studies assessing brain volume and growth in individuals with CHD from the fetus to adolescence. Smaller brain volumes compared to healthy controls are evident from around 30 weeks gestation in fetuses with CHD and are accompanied by increased extracerebral cerebrospinal fluid. This impaired brain growth persists after birth and throughout childhood to adolescence. Risk factors for impaired brain growth include reduced cerebral oxygen delivery in utero, longer time to surgery and increased hospital stay. There is increasing evidence that smaller total and regional brain volumes in this group are associated with adverse neurodevelopmental outcome. However, to date, few studies have assessed the association between early measures of cerebral volume and neurodevelopmental outcome in later childhood. Large prospective multicentre studies are required to better characterise the relationship between brain volume and growth, clinical risk factors and subsequent cognitive, motor, and behavioural impairments in this at-risk population.

Frontal lobe growth is impaired in fetuses with congenital heart disease

OBJECTIVES

The primary objective of this study was to assess whether fetuses with congenital heart disease (CHD) have smaller frontal brain areas compared with normal controls. The secondary objective was to evaluate whether there are any differences in frontal brain area between cases with different types of CHD, grouped according to their impact on hemodynamics.

METHODS

This was a retrospective cross-sectional study, including 421 normal fetuses and 101 fetuses with isolated CHD evaluated between 20 and 39 gestational weeks at our fetal medicine and surgery unit in the period January 2016-December 2019. The study group was subdivided, according to the CHD hemodynamics, as follows: (1) hypoplastic left heart syndrome and other forms of functionally univentricular heart defect; (2) transposition of the great arteries; (3) conotruncal defects and other CHDs with large shunts; (4) right ventricular outflow tract obstruction, without a hypoplastic right ventricle; (5) left outflow tract obstruction; (6) others. The transventricular axial view of the fetal head was used as the reference view, on which the frontal lobe anteroposterior diameter (FAPD) and the occipitofrontal diameter (OFD) were measured, assuming the former to be representative of the area of the frontal lobes. The FAPD/OFD ratio was then calculated as FAPD/OFD × 100. These two variables (FAPD and FAPD/OFD ratio) were then evaluated and compared between the study and control groups. Adjustment for gestational age, both via multiple linear regression and by using a-posteriori matching based on the propensity score, was employed.

RESULTS

In normal fetuses, FAPD showed a linear positive correlation with gestational age. In fetuses with CHD, the FAPD was shorter than in normal fetuses from the 20^th  gestational week onwards, with the difference increasing after 30 gestational weeks. FAPD/OFD ratio was significantly smaller in fetuses with CHD than in normal fetuses (P < 0.0001) at all gestational ages, with no apparent differences among the various CHD categories, all of which had smaller FAPD/OFD ratio compared with controls.

CONCLUSIONS

Fetuses with CHD have a shorter FAPD and a smaller FAPD/OFD ratio compared with normal fetuses. This impaired growth of the frontal area of the brain seems to occur in all types of CHD, regardless of their impact on hemodynamics. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Individualized brain development and cognitive outcome in infants with congenital heart disease

Infants with congenital heart disease are at risk of neurodevelopmental impairments, the origins of which are currently unclear. This study aimed to characterize the relationship between neonatal brain development, cerebral oxygen delivery and neurodevelopmental outcome in infants with congenital heart disease. A cohort of infants with serious or critical congenital heart disease (N = 66; N = 62 born ≥37 weeks) underwent brain MRI before surgery on a 3T scanner situated on the neonatal unit. T2-weighted images were segmented into brain regions using a neonatal-specific algorithm. We generated normative curves of typical volumetric brain development using a data-driven technique applied to 219 healthy infants from the Developing Human Connectome Project (dHCP). Atypicality indices, representing the degree of positive or negative deviation of a regional volume from the normative mean for a given gestational age, sex and postnatal age, were calculated for each infant with congenital heart disease. Phase contrast angiography was acquired in 53 infants with congenital heart disease and cerebral oxygen delivery was calculated. Cognitive and motor abilities were assessed at 22 months (N = 46) using the Bayley scales of Infant and Toddler Development-Third Edition. We assessed the relationship between atypicality indices, cerebral oxygen delivery and cognitive and motor outcome. Additionally, we examined whether cerebral oxygen delivery was associated with neurodevelopmental outcome through the mediating effect of brain volume. Negative atypicality indices in deep grey matter were associated with both reduced neonatal cerebral oxygen delivery and poorer cognitive abilities at 22 months across the whole sample. In infants with congenital heart disease born ≥37 weeks, negative cortical grey matter and total tissue volume atypicality indices, in addition to deep grey matter structures, were associated with poorer cognition. There was a significant indirect relationship between cerebral oxygen delivery and cognition through the mediating effect of negative deep grey matter atypicality indices across the whole sample. In infants born ≥37 weeks, cortical grey matter and total tissue volume atypicality indices were also mediators of this relationship. In summary, lower cognitive abilities in toddlers with congenital heart disease were associated with smaller grey matter volumes before cardiac surgery. The aetiology of poor cognition may encompass poor cerebral oxygen delivery leading to impaired grey matter growth. Interventions to improve cerebral oxygen delivery may promote early brain growth and improve cognitive outcomes in infants with congenital heart disease.

Three-Dimensional Volumetric Magnetic Resonance Imaging Detects Early Alterations of the Brain Growth in Fetuses With Congenital Heart Disease

BACKGROUND

Several published studies have shown alterations of brain development in third-trimester fetuses with congenital heart disease (CHD). However, little is known about the timing and pattern of altered brain development in fetuses with CHD.

PURPOSE

To investigate the changes in the volume of intracranial structures in fetuses with CHD by three-dimensional (3D) volumetric magnetic resonance imaging (MRI) in the earlier stages of pregnancy (median gestational age [GA], 26 weeks).

STUDY TYPE

Retrospective.

POPULATION

Forty women carrying a fetus with CHD (including 20 fetuses with GA <26 weeks) and 120 pregnant women carrying a healthy fetus (including 50 fetuses with GA <26 weeks).

FIELD STRENGTH/SEQUENCE

Two-dimensional single-shot turbo spin echo sequence at 1.5 -T.

ASSESSMENT

Three-dimensional volumetric parameters from slice-to-volume registered images, including cortical gray matter volume (GMV), subcortical brain tissue volume (SBV), intracranial cavity volume (ICV), lateral ventricles volume (VV), cerebellum, brainstem, and extra-cerebrospinal fluid (e-CSF) were quantified by manual segmentation from one primary and two secondary observers.

STATISTICAL TESTS

Volumes were presented graphically with quadratic curve fitting. Scatterplots were produced mapping volumes against GA in normal and CHD fetuses. For GA <26 weeks, Z scores were calculated and Student's t-tests were conducted to compare volumes between the normal and CHD fetuses.

RESULTS

In fetuses with CHD GMV, SBV, cerebellum, and brainstem were significantly reduced (all P < 0.05) in early stages of pregnancy (GA <26 weeks), with differences becoming progressively greater with increasing GA. Compared with normal fetuses, e-CSF, e-CSF to ICV ratio, and VV were higher in fetuses with CHD (all P < 0.05). However, ICV volume and the GMV to SBV ratio were not significantly reduced in the CHD group (P = 0.94 and P = 0.13, respectively) during the middle gestation (GA <26 weeks).

DATA CONCLUSION

There appear to be alterations of brain development trajectory in CHD fetuses that can be detected by 3D volumetric MRI in the earlier stages of pregnancy.

LEVEL OF EVIDENCE

4 TECHNICAL EFFICACY: Stage 3.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Growth trajectories of the human fetal brain in healthy and complicated pregnancies and associations with neurodevelopmental outcome in the early life course

BACKGROUND

There is a need for non-invasive prenatal markers of the brain to assess fetuses at risk for poor postnatal neurodevelopmental outcome. Periconceptional maternal conditions and pregnancy complications impact prenatal brain development.

AIMS

To investigate associations between growth trajectories of fetal brain structures and neurodevelopmental outcome in children in the early life course.

STUDY DESIGN

Periconceptional prospective observational cohort.

SUBJECTS

Singleton pregnancies were included in the Rotterdam periconception cohort. Two- and three-dimensional ultrasound scans at 22, 26 and 32 weeks gestational age were analysed.

OUTCOME MEASURES

Head circumference (HC), cerebellum, corpus callosum (CC), Sylvian fissure, insula and parieto-occipital fissure (POF) were measured. Neurodevelopment was evaluated using the Age-and-Stages-questionnaire-3 (ASQ-3) and the Child-Behaviour-Checklist (CBCL) at 2 years of age. Linear mixed models, used to estimate the prenatal brain growth trajectories, and linear regression models, used to evaluate the associations between prenatal brain structures and neurodevelopmental outcomes, were applied in the total study population, and in subgroups: fetal growth restriction (FGR), preterm birth (PTB), fetal congenital heart disease (CHD), and uncomplicated controls.

RESULTS

Consent for participation was received from parents on behalf of their child 138/203 (68%). ASQ-3 was completed in 128/203 children (63%) and CBCL in 93/203 children (46%). Significant smaller subject-specific growth trajectories (growth rate of CC, HC, left insula, left POF and right POF and the baseline size of CC, HC, left POF and right POF) were found in the FGR subgroup, compared to the other subgroups (all p-values <0.05). In the total group (n = 138), the growth rate of the left insula was associated with poorer ASQ-3 score (β = -869.51; p < 0.05). Healthy controls (n = 106) showed a comparable association (β = -1209.87; p < 0.01). FGR (n = 10) showed a larger baseline size of the right Sylvian fissure in association with poorer CBCL-score (β = 4.13; p < 0.01). In CHD (n = 12) the baseline size of the left Sylvian fissure and its growth rate were associated with respectively poorer and better CBCL-scores (β = 3.11; p < 0.01); (β = -171.99; p < 0.01). In PTB (n = 10) no associations were found.

CONCLUSIONS

This explorative study suggests associations between ultrasound measurements of fetal brain growth and neurodevelopmental outcome at 2 years of age. In future, this non-invasive technique may improve early identification of fetuses at risk for neurodevelopmental outcome and follow-up postnatal clinical care.

The association between flow and oxygenation and cortical development in fetuses with congenital heart defects using a brain-age prediction algorithm

Objectives

Presumably, changes in fetal circulation contribute to the delay in maturation of the cortex in fetuses with congenital heart defect (CHD). The aim of the current study is to analyze fetal brain development based on hemodynamic differences, using novel brain‐age prediction software.

Methods

We have performed detailed neurosonography, including acquiring 3D volumes, prospectively in cases with isolated CHD from 20 weeks onwards. An algorithm that assesses the degree of fetal brain‐age automatically was used to compare CHD cases to controls. We stratified CHD cases according to flow and oxygenation profiles by lesion physiology and performed subgroup analyses.

Results

A total of 616 ultrasound volumes of 162 CHD cases and 75 controls were analyzed. Significant differences in maturation of the cortex were observed in cases with normal blood flow toward the brain (−3.8 days, 95%CI [−5.5; −2.0], P = <.001) and low (−4.0 days, 95% CI [−6.7; −1.2] P = <.05; hypoplastic left heart syndrome[HLHS]) and mixed (−4.4 days, 95%CI [−6.4; −2.5] p = <.001) oxygen saturation in the ascending aorta (TGA) and in cardiac mixing (eg, Fallot) cases.

Conclusion

The current study shows significant delay in brain‐age in TGA and Fallot cases as compared to control cases. However, the small differences found in this study questions the clinical relevance.

Ventricular and total brain volumes in infants with congenital heart disease: a longitudinal study

BACKGROUND

Quantitative MRI techniques help recognize delayed brain development in fetuses with congenital heart disease (CHD). Ventriculomegaly became an early marker of brain dysmaturity.

OBJECTIVE

Evaluate longitudinally the cerebral ventricular and total brain volumes (TBV) in infants with CHD compared to normal neonates: testing the fetal brain dysmaturity and following its progression post operatively.

STUDY DESIGN

Fetal and post-operative MRIs were obtained on fetuses/neonates with CHD requiring invasive intervention within the first month after birth. Volumetric measurement was done with ITK-SNAP and analyzed post-hoc.

RESULTS

Ten cases were evaluated with a significant decrease in ventricular volumes from the fetal to the post-operative neonatal timepoint (p = 0.0297). Infants with HLHS had a significant increase postoperatively in their TBV (p = 0.0396).

CONCLUSIONS

TBV increased post operatively inversely mirrored by the decrement of the ventricular volumes. This could be explained by the establishment an increase of brain blood flow after surgery.

Doppler evaluation of the posterior cerebral artery in fetuses with transposition of great arteries

Objective To observe Doppler ultrasound changes in the two segments of the posterior cerebral artery (PCA) in fetuses with transposition of the great arteries (TGA). Methods The peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI), and velocity-time integral (VTI) of the two segments of PCA (the first segment: PCAS1, the second segment: PCAS2) and of the middle cerebral artery (MCA) were compared in TGA fetuses and normal fetuses. The abnormality rate between the PCAS1-PI and MCA-PI was compared in TGA fetuses. Results The PCAS1-PI and MCA-PI were smaller in the TGA fetuses than in the controls (all P < 0.05), but the PCAS2-PI was unchanged (P > 0.05). The MCA-VTI, PCAS1-VTI, and PCAS2-VTI were larger in the TGA fetuses (all P < 0.05). In the TGA fetuses, the abnormality rate of the PCAS1-PI was significantly higher than that of the MCA-PI (P < 0.05). Conclusion In fetuses with TGA, there were hemodynamic differences between the two segments of the posterior cerebral arteries. Moreover, PCAS1 exhibited signs of vasodilatation more obviously than did the MCA in fetuses with TGA.

Global and Regional Changes in Cortical Development Assessed by MRI in Fetuses with Isolated Nonsevere Ventriculomegaly Correlate with Neonatal Neurobehavior

BACKGROUND AND PURPOSE

Fetuses with isolated nonsevere ventriculomegaly (INSVM) are at risk of presenting neurodevelopmental delay. However, the currently used clinical parameters are insufficient to select cases with high risk and determine whether subtle changes in brain development are present and might be a risk factor. The aim of this study was to perform a comprehensive evaluation of cortical development in INSVM by magnetic resonance (MR) imaging and assess its association with neonatal neurobehavior.

MATERIALS AND METHODS

Thirty-two INSVM fetuses and 29 healthy controls between 26-28 weeks of gestation were evaluated using MR imaging. We compared sulci and fissure depth, cortical maturation grading of specific areas and sulci and volumes of different brain regions obtained from 3D brain reconstruction of cases and controls. Neonatal outcome was assessed by using the Neonatal Behavioral Assessment Scale at a mean of 4 ± 2 weeks after birth.

RESULTS

Fetuses with INSVM showed less profound and underdeveloped sulcation, including the Sylvian fissure (mean depth: controls 16.8 ± 1.9 mm, versus INSVM 16.0 ± 1.6 mm; P = .01), and reduced global cortical grading (mean score: controls 42.9 ± 10.2 mm, versus INSVM: 37.8 ± 9.9 mm; P = .01). Fetuses with isolated nonsevere ventriculomegaly showed a mean global increase of gray matter volume (controls, 276.8 ± 46.0 ×10 mm³, versus INSVM 277.5 ± 49.3 ×10 mm³, P = .01), but decreased mean cortical volume in the frontal lobe (left: controls, 53.2 ± 8.8 ×10 mm³, versus INSVM 52.4 ± 5.4 ×10 mm³; P = < .01). Sulcal depth and brain volumes were significantly associated with the Neonatal Behavioral Assessment Scale severity (P = .005, Nagelkerke R² = 0.732).

CONCLUSIONS

INSVM fetuses showed differences in cortical development, including regions far from the lateral ventricles, that are associated with neonatal neurobehavior. These results suggest the possible use of these parameters to identify cases at higher risk of altered neurodevelopment.

Onset of brain injury in infants with prenatally diagnosed congenital heart disease

BACKGROUND

The exact onset of brain injury in infants with congenital heart disease (CHD) is unknown. Our aim was, therefore, to assess the association between prenatal Doppler flow patterns, postnatal cerebral oxygenation and short-term neurological outcome.

METHODS

Prenatally, we measured pulsatility indices of the middle cerebral (MCA-PI) and umbilical artery (UA-PI) and calculated cerebroplacental ratio (CPR). After birth, cerebral oxygen saturation (rcSO2) and fractional tissue oxygen extraction (FTOE) were assessed during the first 3 days after birth, and during and for 24 hours after every surgical procedure within the first 3 months after birth. Neurological outcome was determined preoperatively and at 3 months of age by assessing general movements and calculating the Motor Optimality Score (MOS).

RESULTS

Thirty-six infants were included. MOS at 3 months was associated with MCA-PI (rho 0.41, P = 0.04), UA-PI (rho -0.39, P = 0.047, and CPR (rho 0.50, P = 0.01). Infants with abnormal MOS had lower MCA-PI (P = 0.02) and CPR (P = 0.01) and higher UA-PI at the last measurement (P = 0.03) before birth. In infants with abnormal MOS, rcSO2 tended to be lower during the first 3 days after birth, and FTOE was significantly higher on the second day after birth (P = 0.04). Intraoperative and postoperative rcSO2 and FTOE were not associated with short-term neurological outcome.

CONCLUSION

In infants with prenatally diagnosed CHD, the prenatal period may play an important role in developmental outcome. Additional research is needed to clarify the relationship between preoperative, intra-operative and postoperative cerebral oxygenation and developmental outcome in infants with prenatally diagnosed CHD.

Evidence for uteroplacental malperfusion in fetuses with major congenital heart defects

AIMS

Fetuses affected by congenital heart defects (CHD) are considered to be at increased risk of fetal growth restriction and intrauterine demise. Whether these risks are a direct consequence of fetal CHD or a result of associated uteroplacental dysfunction is not evident from the data of recent studies. The aim of this study was to investigate the prevalence of uteroplacental dysfunction reflected by abnormal uterine artery Doppler indices and reduced fetal growth in CHD pregnancies.

METHODS

This is a retrospective case-control study including singleton pregnancies referred for detailed fetal cardiac assessment subsequently diagnosed with or without CHD. Mid-trimester uterine artery Doppler assessment at 20-24 weeks as well as third trimester fetal biometry and arterial Doppler pulsatility indices (PI) were performed. All fetal biometry were converted into centiles and Doppler values to multiples of median (MoM) to adjust for physiological changes with gestation.

RESULTS

The study included 811 pregnancies including 153 cases where the fetus was diagnosed with CHD. Mid-pregnancy uterine artery PI was significantly higher in women with fetal CHD compared to controls (0.90MoM vs 0.83MoM; p = 0.006). In the third trimester, median centiles for fetal head circumference (45.4 vs 57.07; p<0.001), abdominal circumference (51.17 vs 55.71; p = 0.014), estimated fetal weight (33.6 vs 56.7; p<0.001) and cerebroplacental ratio (CPR: 0.84MoM vs 0.95MoM; p<0.001) were significantly lower in fetuses with CHD compared to controls. The percentage of small for gestational age births <10th centile (24.0% vs 10.7%; <0.001) and low CPR <0.6MoM (11.7% vs 2.5%; p<0.001) were significantly higher in the fetal CHD cohort.

CONCLUSIONS

Mid-pregnancy uterine artery resistance is increased and subsequent fetal biometry reduced in pregnancies with CHD fetuses. These findings suggest that fetal CHD are associated with uteroplacental dysfunction, secondary to impaired maternal uteroplacental perfusion resulting in relative fetal hypoxaemia and reduced fetal growth.

Cortical development in fetuses with congenital heart defects using an automated brain-age prediction algorithm

INTRODUCTION

Congenital heart defects are associated with neurodevelopmental delay. It is hypothesized that fetuses affected by congenital heart defect have altered cerebral oxygen perfusion and are therefore prone to delay in cortical maturation. The aim of this study was to determine the difference in fetal brain age between consecutive congenital heart defect cases and controls in the second and third trimester using ultrasound.

MATERIAL AND METHODS

Since 2014, we have included 90 isolated severe congenital heart defect cases in the Heart And Neurodevelopment (HAND)-study. Every 4 weeks, detailed neurosonography was performed in these fetuses, including the recording of a 3D volume of the fetal brain, from 20 weeks onwards. In all, 75 healthy fetuses underwent the same protocol to serve as a control group. The volumes were analyzed by automated age prediction software which determines gestational age by the assessment of cortical maturation.

RESULTS

In total, 477 volumes were analyzed using the age prediction software (199 volumes of 90 congenital heart defect cases; 278 volumes of 75 controls). Of these, 16 (3.2%) volume recordings were excluded because of imaging quality. The age distribution was 19-33 weeks. Mixed model analysis showed that the age predicted by brain maturation was 3 days delayed compared with the control group (P = .002).

CONCLUSIONS

This study shows that fetuses with isolated cases of congenital heart defects show some delay in cortical maturation as compared with healthy control cases. The clinical relevance of this small difference is debatable. This finding was consistent throughout pregnancy and did not progress during the third trimester.

New Aspects in the Diagnosis and Therapy of Fetal Hypoplastic Left Heart Syndrome

Fetal hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease with a lethal prognosis without postnatal therapeutic intervention or surgery. The aim of this article is to give a brief overview of new findings in the field of prenatal diagnosis and the therapy of HLHS. As cardiac output in HLHS children depends on the right ventricle (RV), prenatal assessment of fetal RV function is of interest to predict poor functional RV status before the RV becomes the systemic ventricle. Prenatal cardiac interventions such as fetal aortic valvuloplasty and non-invasive procedures such as maternal hyperoxygenation seem to be promising treatment options but will need to be evaluated with regard to long-term outcomes. Novel approaches such as stem cell therapy or neuroprotection provide important clues about the complexity of the disease. New aspects in diagnostics and therapy of HLHS show the potential of a targeted prenatal treatment planning. This could be used to optimize parental counseling as well as pre- and postnatal management of affected children.

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.

Growth patterns and cerebroplacental hemodynamics in fetuses with congenital heart disease

OBJECTIVES

Congenital heart disease (CHD) has been associated with reduced fetal head circumference (HC), although the underlying pathophysiology remains undetermined. We aimed to define trends in fetal growth and cerebroplacental Doppler flow, and to investigate their relationship, in fetuses with CHD.

METHODS

This was a retrospective study in two fetal medicine units in The Netherlands. We included all fetuses with CHD in whom Doppler flow patterns (middle cerebral artery (MCA) pulsatility index (PI), umbilical artery (UA) PI and cerebroplacental ratio (CPR)) and biometry (HC and abdominal circumference (AC)) had been measured serially after 19 weeks' gestation between January 2010 and November 2016. Fetuses were categorized into three groups based on the expected cerebral arterial oxygen saturation of their particular type of CHD: normal; mild to moderately reduced; severely reduced. Trends over time in Z-scores were analyzed using a linear mixed-effects model.

RESULTS

A total of 181 fetuses fulfilled the inclusion criteria. Expected cerebral arterial oxygen saturation in CHD was classified as normal in 44 cases, mild to moderately reduced in 84 and severely reduced in 53. In the cohort overall, average trends over time were significant for both HC and AC Z-scores. HC Z-scores showed a tendency to decrease until 23 weeks, then to increase until 33 weeks, followed by another decrease in the late third trimester. AC Z-scores increased progressively with advancing gestation. MCA-PI and UA-PI Z-scores showed significant trends throughout pregnancy, but CPR Z-scores did not. There were no associations between expected cerebral arterial oxygen saturation and fetal growth. Average trends in MCA-PI Z-scores were significantly different between the three subgroups, whereas those in UA-PI Z-scores and in CPR Z-scores were similar between the subgroups. There was no significant association between MCA-PI and HC Z-scores.

CONCLUSIONS

Fetal biometry and Doppler flow patterns are within normal range in fetuses with CHD, but show trends over time. Head growth in fetuses with CHD is not associated with cerebral blood flow pattern or placental function and HC is not influenced by the cerebral arterial oxygen saturation. © 2018 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of the International Society of Ultrasound in Obstetrics and Gynecology.

Cortical Dysmaturation in Congenital Heart Disease

Congenital heart disease (CHD) is among the most common birth defects. Children with CHD frequently display long-term intellectual and behavioral disability. Emerging evidence indicates that cardiac anomalies lead to a reduction in cerebral oxygenation, which appears to profoundly impact on the maturation of cerebral regions responsible for higher-order cognitive functions. In this review we focus on the potential mechanisms by which dysregulation of cortical neuronal development during early life may lead to the significant cognitive impairments that commonly occur in children with CHD. Further understanding of the mechanisms underlying cortical dysmaturation due to CHD will be necessary to identify strategies for neonatal neuroprotection and for mitigating developmental delays in this patient population.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Brain angiogenic gene expression in fetuses with congenital heart disease

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Circulatory Changes and Cerebral Blood Flow and Oxygenation During Transition in Newborns With Congenital Heart Disease

This review aims to describe how the complex events of cardiovascular transition may affect the brain of infants with congenital heart disease (CHD). In particular, we describe the vulnerabilities of the neonatal brain in the transitional period during and immediately after delivery and propose management strategies that can potentially influence neurodevelopmental outcomes in this patient population. Delayed brain development has been identified in the third trimester fetus with certain forms of CHD. Neonates with critical CHD are at risk for brain injury even before their neonatal operation. The transitional period from fetal to neonatal life is marked with hemodynamic changes that can affect cerebral blood flow and oxygenation and may exacerbate injury and influence outcome. We propose specific perinatal management strategies tailored to maternal-fetal pairs aimed at optimizing hemodynamic stability, especially cerebral blood flow and oxygenation, to maximize the neurodevelopmental potential of infants with CHD.

Prenatal Growth in Fetuses with Isolated Cyanotic and Non-Cyanotic Congenital Heart Defects

BACKGROUND

Fetal growth may vary significantly in different congenital heart defects (CHDs).

OBJECTIVES

To investigate prenatal growth of CHD fetuses and its correlation with classifications based upon expected oxygen delivery to the fetal brain or structural findings.

METHODS

Seventy-nine euploid fetuses with isolated CHD were recruited prospectively and categorized by the expected oxygen supply to the brain (low, intermediate, and high) or by the expected arterial mixing considering two categories (cyanotic or non-cyanotic). Biometry and Doppler were recorded, and Z-scores (Zs) calculated. Growth changes at different time points were analyzed and compared with 150 controls.

RESULTS

A total of 664 exams were performed on 229 fetuses. Median head circumference (HC) Zs were lower in all CHD fetuses from the second trimester onwards and in cyanotic CHD fetuses from the first onwards, with associated smaller abdominal circumference (AC) in the third trimester (first-trimester biparietal diameter Zs cyanotic: -1.3 [-2.36; -0.98], non-cyanotic -0.72 [-1.25; -0.6], p = 0.044, second-trimester HC Zs cyanotic: -1.47 [-2.3; -0.84]; non-cyanotic -0.45 [-0.83; -0.02], p < 0.0001; AC Zs cyanotic 0.0 [-0.44; 0.86]; non-cyanotic 0.65 [0.31; 1], p = 0.0006). Birth-weight centiles were smaller in CHDs (particularly in cyanotic) with no differences between categories of brain oxygen delivery.

CONCLUSIONS

Fetuses with cyanotic CHD have fetal growth restriction, impaired head growth, yet normal posterior fossa dimensions and fetal-placental Doppler.

Relationship Between Cavum Septi Pellucidi Measurements and Fetal Hypoplastic Left Heart Syndrome or Dextro-Transposition of the Great Arteries

OBJECTIVES

The aim of this study was to compare the size and position of the cavum septi pellucidi (CSP) in fetuses with hypoplastic left heart syndrome (HLHS) or dextro-transposition of the great arteries (d-TGA) with healthy fetuses.

METHODS

The CSP length, CSP width, and frontal lobe length were measured in 185 healthy fetuses (404 scans), 11 fetuses with HLHS (16 scans), and 11 fetuses with d-TGA (12 scans) between January 2005 and April 2016. Each measurement was compared between healthy fetuses and those with HLHS or d-TGA, controlling for the biparietal diameter.

RESULTS

Positive correlations were noted between biparietal diameter and CSP length, CSP width, and frontal lobe length (adjusted R²  = 0.811, 0.821, and 0.878, respectively). An increased CSP length was found in both fetuses with HLHS and those with d-TGA (P < .0001). The CSP width was only increased in fetuses with d-TGA (P = .0466). No difference in the frontal lobe length was noted.

CONCLUSIONS

In fetuses with HLHS, the CSP is increased in length. In fetuses with d-TGA, the CSP is increased in both length and width.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Volumetric Brain MRI Study in Fetuses with Congenital Heart Disease

BACKGROUND AND PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Different vasodilatation characteristics among the main cerebral arteries in fetuses with congenital heart defects

To observe Doppler changes in the three main cerebral arteries in fetuses with congenital heart defects (CHDs). The pulsatility index (PI) values of the anterior cerebral artery (ACA), middle cerebral artery (MCA), and posterior cerebral artery (PCA) were prospectively compared in 78 CHD fetuses and 78 normal control fetuses. Correlations between the cerebral artery PIs and the neurodevelopment scores (psychomotor development index [PDI] and mental development index [MDI]) were assessed. The MCA-PI was decreased significantly in fetuses with hypoplastic left heart syndrome (HLHS). The ACA-PI was reduced significantly in fetuses with HLHS, fetuses with left-sided obstructive lesions (LSOLs) and fetuses with transposition of the great arteries. The PCA-PI was significantly smaller in fetuses with HLHS and fetuses with LSOLs. More fetuses presented signs of cerebral vasodilatation of the ACA than the MCA for certain types of CHD (P < 0.05). The ACA-PI was positively correlated with the PDI and MDI scores in fetuses with CHDs (r² = 0.26, 0.20, P < 0.01). The MCA-PI was only positively correlated with the PDI scores (r² = 0.15, P < 0.01). The ACA exhibited signs of vasodilatation more frequently and severely than the MCA. The ACA-PI appears to be more sensitive for predicting abnormal neurodevelopmental outcomes than the MCA-PI.

Fetal major cardiac defects and placental dysfunction at 11-13 weeks' gestation

OBJECTIVE

To investigate the relationship between fetal major cardiac defects and markers of placental perfusion and function.

METHODS

This was a prospective screening study in singleton pregnancies at 11-13 weeks' gestation. Uterine artery pulsatility index (UtA-PI), serum pregnancy-associated plasma protein-A (PAPP-A) and placental growth factor (PlGF) were measured and the values were converted into multiples of the normal median (MoM). Median MoM values in fetuses with isolated major cardiac defects were compared with those in fetuses without major defects.

RESULTS

The 50 094 singleton pregnancies fulfilling the entry criteria included 49 898 pregnancies with normal cardiac anatomy and 196 (0.39%) with major congenital cardiac defects: 73 (37.2%) with conotruncal defects, 63 (32.1%) with left ventricular outflow tract defects and 60 (30.6%) with valvular defects. In the group with cardiac defects, compared with controls, there was lower median PAPP-A MoM (0.81 vs 1.00, P < 0.0001) and PlGF MoM (0.78 vs 1.00, P < 0.0001) but no significant difference in UtA-PI MoM (1.01 vs 1.00, P = 0.162).

CONCLUSION

In pregnancies with isolated fetal major cardiac defects, there is evidence of placental dysfunction in the absence of impaired placental perfusion. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Food and Drug Administration warning on anesthesia and brain development: implications for obstetric and fetal surgery

There has been growing concern about the detrimental effects of certain anesthetic agents on the developing brain. Preclinical studies in small animal models as well as nonhuman primates suggested loss or death of brain cells and consequent impaired neurocognitive function following anesthetic exposure in neonates and late gestation fetuses. Human studies in this area are limited and currently inconclusive. On Dec. 14, 2016, the US Food and Drug Administration issued a warning regarding impaired brain development in children following exposure to certain anesthetic agents used for general anesthesia, namely the inhalational anesthetics isoflurane, sevoflurane, and desflurane, and the intravenous agents propofol and midazolam, in the third trimester of pregnancy. Furthermore, this warning recommends that health care professionals should balance the benefits of appropriate anesthesia in young children and pregnant women against potential risks, especially for procedures that may last >3 hours or if multiple procedures are required in children <3 years old. The objective of this article is to highlight how the Food and Drug Administration warning may impact the anesthetic and surgical management of the obstetric patient. Neuraxial anesthesia (epidural or spinal anesthesia) is more commonly administered for cesarean delivery than general anesthesia. The short duration of fetal exposure to general anesthesia during cesarean delivery has not been associated with learning disabilities. However, the fetus can also be exposed to both intravenous and inhalation anesthetics during nonobstetric or fetal surgery in the second and third trimester; this exposure is typically longer than that for cesarean delivery. Very few studies address the effect of anesthetic exposure on the fetus in the second trimester when most nonobstetric and fetal surgical procedures are performed. It is also unclear how the plasticity of the fetal brain at this stage of development will modulate the consequences of anesthetic exposure. Strategies that may circumvent possible untoward long-term neurologic effects of anesthesia in the baby include: (1) use of nonimplicated (nongamma-aminobutyric acid agonist) agents for sedation such as opioids (remifentanil, fentanyl) or the alpha-2 agonist, dexmedetomidine, when appropriate; (2) minimizing the duration of exposure to inhalational anesthetics for fetal, obstetric, and nonobstetric procedures in the pregnant patient, as much as possible within safe limits; and (3) commencing surgery promptly and limiting the interval between induction of anesthesia and surgery start time will help decrease patient exposure to inhalational agents. While the Food and Drug Administration warning was based on duration and repetitive nature of exposure rather than concentration of inhalational agents, intravenous tocolytics can be considered for intraoperative use, to provide uterine relaxation for fetal surgery, in lieu of high concentrations of inhalational anesthetic agents. Practitioners should consider the type of anesthesia that will be administered and the potential risks when scheduling patients for nonobstetric and fetal surgery.