Impaired Maternal-Fetal Environment and Risk for Preoperative Focal White Matter Injury in Neonates With Complex Congenital Heart Disease

Cerebral Microhemorrhages in Children With Congenital Heart Disease: Prevalence, Risk Factors, and Association With Neurodevelopmental Outcomes

BACKGROUND

Infants with congenital heart disease require early lifesaving heart surgery, which increases risk for brain injury and neurodevelopmental delay. Cerebral microhemorrhages (CMH) are frequently seen after surgery, but whether they are benign or constitute injury is unknown.

METHODS AND RESULTS

One hundred ninety-two infants with congenital heart disease undergoing cardiac surgery with cardiopulmonary bypass were evaluated with pre- (n=183) and/or postoperative (n=162) magnetic resonance imaging. Perioperative risk factors for CMH and neurodevelopmental outcomes were analyzed using linear regression. Eighteen-month neurodevelopmental outcomes were assessed in a subset of patients (n=82). The most common congenital heart disease subtypes were hypoplastic left heart syndrome (37%) and transposition of the great arteries (33%). Forty-two infants (23%) had CMH present on magnetic resonance imaging presurgery and 137 infants (85%) postsurgery. We found no significant risk factors for preoperative CMH. In multivariable analysis, neurodevelopmental duration (P<0.0001), use of extracorporeal membrane oxygenation support (P<0.0005), postoperative seizure(s) (P=0.02), and lower birth weight (P=0.03) were associated with new or worsened CMH postoperatively. A higher CMH number was associated with lower motor scores (P=0.01) at 18 months.

CONCLUSIONS

CMH are common imaging findings in infants with congenital heart disease, particularly after cardiopulmonary bypass conferring adverse impact on neurodevelopmental outcomes at 18 months. Longer duration of cardiopulmonary bypass and extracorporeal membrane oxygenation use demonstrated greatest risk for developing CMH. However, the presence of CMH on preoperative scans indicates yet unidentified nonperioperative risk factors. Neuroprotective strategies to mitigate CMH risk may improve neurodevelopmental outcomes in this vulnerable population.

Congenital Heart Disease Fetuses Have Decreased Mid-Gestational Placental Flow, Placental Malperfusion Defects, and Impaired Growth

Background

Placental health may impact the development and outcomes of congenital heart disease (CHD). CHD fetuses have been shown retrospectively to have decreased placental blood flow.

Objectives

The purpose of this study was to determine if CHD fetuses with decreased placental blood flow have placental pathology at birth and if there is a relationship between placental blood flow, placental pathology, and outcomes.

Methods

We performed a prospective case-control study of 38 CHD fetuses, including 28 with single ventricle physiology and 36 controls. Demographic, clinical, and postnatal biometric data were collected. Umbilical venous volume flow (UVVF) was measured from 2nd trimester fetal echocardiograms. Placentas underwent standardized pathological analysis. Standard descriptive statistics and regression analyses were performed to analyze the relationship between UVVF, placental defects, and outcomes.

Results

CHD fetuses had a 15% decrease in mid-gestational UVVF indexed to fetal weight (P < 0.01), and a 27% reduction in UVVF as a proportion of fetal cardiac output (P < 0.01) compared to controls. CHD fetuses had increased placental maternal vascular malperfusion (MVM) lesions (44% vs 18%, P < 0.05), especially high-grade MVM (39% vs 9.1%, P = 0.05), and a trend toward increased placental fetal vascular malperfusion lesions (42% vs 23%, P = 0.10). Placental MVM but not fetal vascular malperfusion lesions were associated with decreased birth weight in CHD fetuses (P < 0.001). There was no association between UVVF and placental pathologic findings or fetal growth.

Conclusions

CHD (particularly single ventricle) fetuses have decreased mid-gestational placental blood flow, increased placental malperfusion defects, and impaired fetal growth. Placental MVM may influence impaired fetal growth in CHD.

Cerebral Protection in Pediatric Cardiac Surgery

Cardiac surgery, both adult and pediatric, has developed very rapidly and impressively over the past 7 decades. Pediatric cardiac surgery, in particular, has revolutionized the management of babies born with congenital heart disease such that now most patients reach adult life and lead comfortable lives. However, these patients are at risk of cerebral lesions, which may be due to perioperative factors, such as side effects of cardiopulmonary bypass and/or anesthesia, and non-perioperative factors such as chromosomal anomalies (common in children with congenital heart disease), the timing of surgery, number of days on the intensive care unit, length of hospitalization and other hospitalizations in the first year of life. The risk of cerebral lesions is particularly relevant to pediatric cardiac surgery given that cerebral metabolism is about 30% higher in neonates, infants and young children compared to adults, which renders their brain more susceptible to ischemic/hypoxic injury. This issue has been a major concern throughout the history of cardiac surgery such that many preventive measures have been implemented over the years. These measures, however, have had only a modest impact and cerebral lesions continue to be a major concern. This is the subject of this review article, which aims to outline these protective measures, offer possible explanations of why these have not resolved the issue, and suggest possible actions that ought to be taken now.

Providing pediatric neurocritical education across the ages: Bridging of neonatal neurocritical care into pediatric neurocritical care training

Pediatric neurocritical care is a field dedicated to providing specialized assessment and care of critically-ill children with neurologic disease or at risk of neurologic compromise. Fellowship programs for providers interested in specializing in pediatric neurocritical care are growing and developing to meet the needs of trainees and the patient populations that they serve. Fetal and neonatal neurocritical care fellowship remains a separate opportunity for training; however, inclusion of fetal and neonatal neurology education into pediatric neurocritical care broadens understanding of normal and pathologic anatomy and physiology, diagnostic interpretation of the developing brain, targeted management interventions, family counseling and prognostication, and long-term optimization of outcomes. For instance, the care of neurologic injury in congenital heart disease emphasizes the incorporation of medical education across the lifespan. Additionally, neonates requiring NICU admission and care are more likely to require future PICU care and be served by neurocritical care providers. Furthermore, neonates with neurologic injury or at risk for neurologic injury are not exclusively admitted to neonatal units. Education across the age-spectrum inclusive of fetal and neonatal neurology is valuable for trainees in understanding underlying disease processes, management, and sequelae and promotes the growth of the field of pediatric neurocritical care.

Progesterone for Neurodevelopment in Fetuses With Congenital Heart Defects: A Randomized Clinical Trial

Importance

Neurodevelopmental outcomes for children with congenital heart defects (CHD) have improved minimally over the past 20 years.

Objectives

To assess the feasibility and tolerability of maternal progesterone therapy as well as the magnitude of the effect on neurodevelopment for fetuses with CHD.

Design, Setting, and Participants

This double-blinded individually randomized parallel-group clinical trial of vaginal natural progesterone therapy vs placebo in participants carrying fetuses with CHD was conducted between July 2014 and November 2021 at a quaternary care children's hospital. Participants included maternal-fetal dyads where the fetus had CHD identified before 28 weeks' gestational age and was likely to need surgery with cardiopulmonary bypass in the neonatal period. Exclusion criteria included a major genetic or extracardiac anomaly other than 22q11 deletion syndrome and known contraindication to progesterone. Statistical analysis was performed June 2022 to April 2024.

Intervention

Participants were 1:1 block-randomized to vaginal progesterone or placebo by diagnosis: hypoplastic left heart syndrome (HLHS), transposition of the great arteries (TGA), and other CHD diagnoses. Treatment was administered twice daily between 28 and up to 39 weeks' gestational age.

Main Outcomes and Measures

The primary outcome was the motor score of the Bayley Scales of Infant and Toddler Development-III; secondary outcomes included language and cognitive scales. Exploratory prespecified subgroups included cardiac diagnosis, fetal sex, genetic profile, and maternal fetal environment.

Results

The 102 enrolled fetuses primarily had HLHS (n = 52 [50.9%]) and TGA (n = 38 [37.3%]), were more frequently male (n = 67 [65.7%]), and without genetic anomalies (n = 61 [59.8%]). The mean motor score differed by 2.5 units (90% CI, -1.9 to 6.9 units; P = .34) for progesterone compared with placebo, a value not statistically different from 0. Exploratory subgroup analyses suggested treatment heterogeneity for the motor score for cardiac diagnosis (P for interaction = .03) and fetal sex (P for interaction = .04), but not genetic profile (P for interaction = .16) or maternal-fetal environment (P for interaction = .70).

Conclusions and Relevance

In this randomized clinical trial of maternal progesterone therapy, the overall effect was not statistically different from 0. Subgroup analyses suggest heterogeneity of the response to progesterone among CHD diagnosis and fetal sex.

Trial Registration

ClinicalTrials.gov Identifier: NCT02133573.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

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.

Cerebral microhemorrhages in children with congenital heart disease: Prevalence, risk factors, and impact on neurodevelopmental outcomes

Background

Infants with complex congenital heart disease (CHD) require life-saving corrective/palliative heart surgery in the first weeks of life. These infants are at risk for brain injury and poor neurodevelopmental outcomes. Cerebral microhemorrhages (CMH) are frequently seen after neonatal bypass heart surgery, but it remains unknown if CMH are a benign finding or constitute injury. Herein, we investigate the risk factors for developing CMH and their clinical significance.

Methods

192 infants with CHD undergoing corrective cardiac surgery with cardiopulmonary bypass (CPB) at a single institution were prospectively evaluated with pre-(n = 183) and/or postoperative (n = 162) brain magnetic resonance imaging (MRI). CMH severity was scored based on total number of microhemorrhages. Antenatal, perioperative, and postoperative candidate risk factors for CMH and neurodevelopmental (ND) outcomes were analyzed. Eighteen-month neurodevelopmental outcomes were assessed using the Bayley-III Scales of Infants and Toddler Development in a subset of patients (n = 82). Linear regression was used to analyze associations between risk factors or ND outcomes and presence/number of CMH.

Results

The most common CHD subtypes were hypoplastic left heart syndrome (HLHS) (37%) and transposition of the great arteries (TGA) (33%). Forty-two infants (23%) had CMH present on MRI before surgery and 137 infants (85%) post-surgery. No parameters evaluated were significant risk factors for preoperative CMH. In multivariate analysis, cardiopulmonary bypass (CPB) duration (p < 0.0001), use of extracorporeal membrane oxygenation (ECMO) support (p < 0.0005), postoperative seizure(s) (p < 0.03), and lower birth weight (p < 0.03) were associated with new or worsened CMH postoperatively. Higher CMH number was associated with lower scores on motor (p < 0.03) testing at 18 months.

Conclusion

CMH is a common imaging finding in infants with CHD with increased prevalence and severity after CPB and adverse impact on neurodevelopmental outcomes starting at a young age. Longer duration of CPB and need for postoperative ECMO were the most significant risk factors for developing CMH. However, presence of CMH on preoperative scans indicates non-surgical risk factors that are yet to be identified. Neuroprotective strategies to mitigate risk factors for CMH may improve neurodevelopmental outcomes in this vulnerable population.

Commentary on "Brain Injury During Transition in the Newborn With Congenital Heart Disease: Hazards of the Preoperative Period"

BRAIN INJURY DURING TRANSITION IN THE NEWBORN WITH CONGENITAL HEART DISEASE: HAZARDS OF THE PREOPERATIVE PERIOD: Jennifer M. Lynch, J. William Gaynor, Daniel J. Licht Seminars in Pediatric Neurology Volume 28, December 2018, Pages 60-65 Infants born with critical congenital heart disease are at risk for neurodevelopmental morbidities later in life. In-utero differences in fetal circulation lead to vulnerabilities which lead to an increased incidence of stroke, white matter injury, and brain immaturity. Recent work has shown these infants may be most vulnerable to brain injury during the early neonatal period when they are awaiting their cardiac surgeries. Novel imaging and monitoring modalities are being employed to investigate this crucial time period and elucidate the precise timing and cause of brain injury in this population.