An MRI Study of Neurological Injury Before and After Congenital Heart Surgery

Individualized cortical gyrification in neonates with congenital heart disease

Congenital heart disease is associated with impaired early brain development and adverse neurodevelopmental outcomes. This study investigated how individualized measures of preoperative cortical gyrification index differ in 142 infants with congenital heart disease, using a normative modelling approach with reference data from 320 typically developing infants. Gyrification index Z-scores for the whole brain and six major cortical areas were generated using two different normative models: one accounting for post-menstrual age at scan, post-natal age at scan and sex, and another additionally accounting for supratentorial brain volume. These Z-scores were compared between congenital heart disease and control groups to test the hypothesis that cortical folding in infants with congenital heart disease deviates from the normal developmental trajectory. The relationships between whole-brain gyrification index Z-scores from the two normative models and both cerebral oxygen delivery and neurodevelopmental outcomes were also investigated. Global and regional brain gyrification was significantly reduced in neonates with congenital heart disease, but not when supratentorial brain volume was accounted for. This finding suggests that whilst cortical folding is reduced in congenital heart disease, it is primarily driven by a reduction in brain size. There was a significant positive correlation between cerebral oxygen delivery and whole-brain gyrification index Z-scores in congenital heart disease, but not when supratentorial brain volume was accounted for. Cerebral oxygen delivery is therefore likely to play a more important role in the biological processes underlying volumetric brain growth than cortical folding. No significant associations between whole-brain gyrification index Z-scores and motor/cognitive outcomes or autism traits were identified in the 70 infants with congenital heart disease who underwent neurodevelopmental assessment at 22-months. Our results suggest that chronic in utero and early post-natal hypoxia in congenital heart disease is associated with reductions in cortical folding that are proportional to reductions in supratentorial brain volume.

Establishing Optimal Control Cohorts for Phase 1 Trials: Retrospective Analysis of Clinical and Biological Outcomes in Neonates and Infants Undergoing Two-Ventricle Repair

Phase 1 trials are primarily conducted to evaluate the safety and feasibility of new interventions, usually without recruiting control patients. This retrospective study aims to characterize clinical and biological outcomes in historical and contemporary cases of neonates and infants undergoing two-ventricle repair to facilitate future secondary endpoint analyses for such trials. This retrospective study included neonates/infants (ages ≤ 6 months) who underwent two-ventricle repair between 2015 and 2021 using the same criteria as our phase 1 trial (n = 199). Patients were allocated into the ventricular septal defect (n = 61), the Tetralogy of Fallot (TOF, n = 88), and the transposition of the great arteries (n = 50) groups with an additional comparison between two eras (2015-2019 vs. 2020-2021). Patient characteristics and most variables assessed were different between the three diagnostic groups indicating the importance of diagnostic matching for secondary analyses. Although the era did not alter cerebral/somatic oxygenation, ventricular function, neuroimaging findings, and complication rates, we observed improvement of inotropic and/or vasoactive-inotropic scores in all groups during the more recent era. In 2020-2021, the age and the body weight at the operation were higher, and hospital stay was shorter in the TOF group, suggesting the possible impact of the pandemic. Results also indicated that matching altered characteristics such as age at operation that may limit the temporal effects and optimize secondary analyses. Using optimal contemporary cases and historical data based on this study will assist in developing a comprehensive study design for a future efficacy/effectiveness trial.

Fetal circulatory physiology and brain development in complex congenital heart disease: A multi-modal imaging study

OBJECTIVE

Fetuses with complex congenital heart disease have altered physiology, contributing to abnormal neurodevelopment. The effects of altered physiology on brain development have not been well studied. We used multi-modal imaging to study fetal circulatory physiology and brain development in hypoplastic left heart syndrome (HLHS) and d-transposition of the great arteries (TGA).

METHODS

This prospective, cross-sectional study investigated individuals with fetal congenital heart disease and controls undergoing fetal echocardiography and fetal brain MRI. MRI measured total brain volume and cerebral oxygenation by the MRI quantification method T2*. Indexed cardiac outputs (CCOi) and vascular impedances were calculated by fetal echocardiography. Descriptive statistics assessed MRI and echocardiogram measurement relationships by physiology.

RESULTS

Sixty-six participants enrolled (control = 20; HLHS = 25; TGA = 21), mean gestational age 33.8 weeks (95% CI: 33.3-34.2). Total brain volume and T2* were significantly lower in fetuses with cardiac disease. CCOi was lower in HLHS, correlating with total brain volume - for every 10% CCOi increase, volume increased 8 mm3 (95% CI: 1.78-14.1; p = 0.012). Echocardiography parameters and cerebral oxygenation showed no correlation. TGA showed no CCOi or aortic output correlation with MRI measures.

CONCLUSIONS

In HLHS, lower cardiac output is deleterious to brain development. Our findings provide insight into the role of fetal cardiovascular physiology in brain health.

Monitoring of cerebral blood flow autoregulation: physiologic basis, measurement, and clinical implications

Cerebral blood flow (CBF) autoregulation is the physiologic process whereby blood supply to the brain is kept constant over a range of cerebral perfusion pressures ensuring a constant supply of metabolic substrate. Clinical methods for monitoring CBF autoregulation were first developed for neurocritically ill patients and have been extended to surgical patients. These methods are based on measuring the relationship between cerebral perfusion pressure and surrogates of CBF or cerebral blood volume (CBV) at low frequencies (<0.05 Hz) of autoregulation using time or frequency domain analyses. Initially intracranial pressure monitoring or transcranial Doppler assessment of CBF velocity was utilised relative to changes in cerebral perfusion pressure or mean arterial pressure. A more clinically practical approach utilising filtered signals from near infrared spectroscopy monitors as an estimate of CBF has been validated. In contrast to the traditional teaching that 50 mm Hg is the autoregulation threshold, these investigations have found wide interindividual variability of the lower limit of autoregulation ranging from 40 to 90 mm Hg in adults and 20-55 mm Hg in children. Observational data have linked impaired CBF autoregulation metrics to adverse outcomes in patients with traumatic brain injury, ischaemic stroke, subarachnoid haemorrhage, intracerebral haemorrhage, and in surgical patients. CBF autoregulation monitoring has been described in both cardiac and noncardiac surgery. Data from a single-centre randomised study in adults found that targeting arterial pressure during cardiopulmonary bypass to above the lower limit of autoregulation led to a reduction of postoperative delirium and improved memory 1 month after surgery compared with usual care. Together, the growing body of evidence suggests that monitoring CBF autoregulation provides prognostic information on eventual patient outcomes and offers potential for therapeutic intervention. For surgical patients, personalised blood pressure management based on CBF autoregulation data holds promise as a strategy to improve patient neurocognitive outcomes.

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.

Gut microbiota-derived cholic acid mediates neonatal brain immaturity and white matter injury under chronic hypoxia

Chronic hypoxia, common in neonates, disrupts gut microbiota balance, which is crucial for brain development. This study utilized cyanotic congenital heart disease (CCHD) patients and a neonatal hypoxic rat model to explore the association. Both hypoxic rats and CCHD infants exhibited brain immaturity, white matter injury (WMI), brain inflammation, and motor/learning deficits. Through 16s rRNA sequencing and metabolomic analysis, a reduction in B. thetaiotaomicron and P. distasonis was identified, leading to cholic acid accumulation. This accumulation triggered M1 microglial activation and inflammation-induced WMI. Administration of these bacteria rescued cholic acid-induced WMI in hypoxic rats. These findings suggest that gut microbiota-derived cholic acid mediates neonatal WMI and brain inflammation, contributing to brain immaturity under chronic hypoxia. Therapeutic targeting of these bacteria provides a non-invasive intervention for chronic hypoxia patients.

Perioperative Brain Injury in Relation to Early Neurodevelopment Among Children with Severe Congenital Heart Disease: Results from a European Collaboration

OBJECTIVE

To examine the relationship between perioperative brain injury and neurodevelopment during early childhood in patients with severe congenital heart disease (CHD).

STUDY DESIGN

One hundred and seventy children with CHD and born at term who required cardiopulmonary bypass surgery in the first 6 weeks after birth were recruited from 3 European centers and underwent preoperative and postoperative brain MRIs. Uniform description of imaging findings was performed and an overall brain injury score was created, based on the sum of the worst preoperative or postoperative brain injury subscores. Motor and cognitive outcomes were assessed with the Bayley Scales of Infant and Toddler Development Third Edition at 12 to 30 months of age. The relationship between brain injury score and clinical outcome was assessed using multiple linear regression analysis, adjusting for CHD severity, length of hospital stay (LOS), socioeconomic status (SES), and age at follow-up.

RESULTS

Neither the overall brain injury score nor any of the brain injury subscores correlated with motor or cognitive outcome. The number of preoperative white matter lesions was significantly associated with gross motor outcome after correction for multiple testing (P = .013, β = -0.50). SES was independently associated with cognitive outcome (P < .001, β = 0.26), and LOS with motor outcome (P < .001, β = -0.35).

CONCLUSION

Preoperative white matter lesions appear to be the most predictive MRI marker for adverse early childhood gross motor outcome in this large European cohort of infants with severe CHD. LOS as a marker of disease severity, and SES influence outcome and future intervention trials need to address these risk factors.

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.

Severe Congenital Heart Defects and Cerebral Palsy

OBJECTIVE

To report the prevalence of cerebral palsy (CP) in children with severe congenital heart defects (sCHD) and the outcome/severity of the CP.

METHODS

Population-based, data linkage study between CP and congenital anomaly registers in Europe and Australia. The EUROCAT definition of severe CHD (sCHD) was used. Linked data from 4 regions in Europe and 2 in Australia were included. All children born in the regions from 1991 through 2009 diagnosed with CP and/or sCHD were included. Linkage was completed locally. Deidentified linked data were pooled for analyses.

RESULTS

The study sample included 4989 children with CP and 3684 children with sCHD. The total number of livebirths in the population was 1 734 612. The prevalence of CP was 2.9 per 1000 births (95% CI, 2.8-3.0) and the prevalence of sCHD was 2.1 per 1000 births (95% CI, 2.1-2.2). Of children with sCHD, 1.5% (n = 57) had a diagnosis of CP, of which 35 (61%) children had prenatally or perinatally acquired CP (resulting from a brain injury at ≤28 days of life) and 22 (39%) children had a postneonatal cause (a brain injury between 28 days and 2 years). Children with CP and sCHD more often had unilateral spastic CP and more intellectual impairments than children with CP without congenital anomalies.

CONCLUSIONS

In high-income countries, the proportion of children with CP is much higher in children with sCHD than in the background population. The severity of disease in children with CP and sCHD is milder compared with children with CP without congenital anomalies.

Functional brain connectivity after corrective cardiac surgery for critical congenital heart disease: a preliminary near-infrared spectroscopy (NIRS) report

Patients with congenital heart disease (CHD) requiring cardiac surgery in infancy are at high risk for neurodevelopmental impairments. Neonatal imaging studies have reported disruptions of brain functional organization before surgery. Yet, the extent to which functional network alterations are present after cardiac repair remains unexplored. This preliminary study aimed at investigating cortical functional connectivity in 4-month-old infants with repaired CHD, using resting-state functional near-infrared spectroscopy (fNIRS). After fNIRS signal frequency decomposition, we compared values of magnitude-squared coherence as a measure of connectivity strength, between 21 infants with corrected CHD and 31 healthy controls. We identified a subset of connections with differences between groups at an uncorrected statistical level of p < .05 while controlling for sex and maternal socioeconomic status, with most of these connections showing reduced connectivity in infants with CHD. Although none of these differences reach statistical significance after FDR correction, likely due to the small sample size, moderate to large effect sizes were found for group-differences. If replicated, these results would therefore suggest preliminary evidence that alterations of brain functional connectivity are present in the months after cardiac surgery. Additional studies involving larger sample size are needed to replicate our data, and comparisons between pre- and postoperative findings would allow to further delineate alterations of functional brain connectivity in this population.

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.

Preterm congenital heart disease and neurodevelopment: the importance of looking beyond the initial hospitalization

Congenital heart disease (CHD) and prematurity are leading causes of infant mortality in the United States. Infants with CHD born prematurely are often described as facing "double jeopardy" with vulnerability from their underlying heart disease and from organ immaturity. They endure additional complications of developing in the extrauterine environment while healing from interventions for heart disease. While morbidity and mortality for neonates with CHD have declined over the past decade, preterm neonates with CHD remain at higher risk for adverse outcomes. Less is known about their neurodevelopmental and functional outcomes. In this perspective paper, we review the prevalence of preterm birth among infants with CHD, highlight the medical complexity of these infants, and emphasize the importance of exploring outcomes beyond survival. We focus on current knowledge regarding overlaps in the mechanisms of neurodevelopmental impairment associated with CHD and prematurity and discuss future directions for improving neurodevelopmental outcomes.

Perioperative EEG background and discharge abnormalities in children undergoing cardiac surgery: a prospective single-centre observational study

BACKGROUND

We analysed the characteristics of abnormal electroencephalogram (EEG) patterns before, during, and 48 h after cardiac surgery in patients with heterogeneous congenital heart disease to assess their relationship to demographic and perioperative variables and to early patient outcomes.

METHODS

In 437 patients enrolled in a single centre, EEG was evaluated for background (including sleep-wake cycle) and discharge (seizures, spikes/sharp waves, pathological delta brushes) abnormalities. Clinical data (arterial blood pressure, doses of inotropic drugs, and serum lactate concentrations) were recorded every 3 h. Postoperative brain MRI was performed before discharge.

RESULTS

Preoperative, intraoperative, and postoperative EEG was monitored in 139, 215, and 437 patients, respectively. Patients with a degree of preoperative background abnormalities (n=40) had more severe intraoperative and postoperative EEG abnormalities (P<0.0001). Intraoperatively, 106/215 (49.3%) patients progressed into an isoelectric EEG. Longer durations of isoelectric EEG were associated with more severe postoperative EEG abnormalities and brain injury on MRI (Ps≤0.003). Postoperative background abnormalities occurred in 218/437 (49.9%) patients, and 119 (54.6%) of them had not recovered after surgery. Seizures occurred in 36/437 (8.2%) patients, spikes/sharp waves in 359/437 (82.2%), and pathological delta brushes in 9/437 (2.0%). Postoperative EEG abnormalities correlated with degree of brain injury on MRI (Ps≤0.02). Demographic and perioperative variables were significantly correlated with postoperative EEG abnormalities, which in turn correlated with adverse clinical outcomes.

CONCLUSIONS

Perioperative EEG abnormalities occurred frequently and correlated with numerous demographic and perioperative variables and adversely correlated with postoperative EEG abnormalities and early outcomes. The relation of EEG background and discharge abnormalities with long-term neurodevelopmental outcomes remains to be explored.

Cerebral Autoregulation Status in Relation to Brain Injury on Electroencephalogram and Magnetic Resonance Imaging in Children Following Cardiac Surgery

Background Disturbed cerebral autoregulation has been reported in children with congenital heart disease before and during cardiopulmonary bypass surgery, but not after. We sought to characterize the cerebral autoregulation status in the early postoperative period in relation to perioperative variables and brain injuries. Methods and Results A prospective and observational study was conducted in 80 patients in the first 48 hours following cardiac surgery. Cerebral oximetry/pressure index (COPI) was retrospectively calculated as a moving linear correlation coefficient between mean arterial blood pressure and cerebral oxygen saturation. Disturbed autoregulation was defined as COPI >0.3. Correlations of COPI with demographic and perioperative variables as well as brain injuries on electroencephalogram and magnetic resonance imaging and early outcomes were analyzed. Thirty-six (45%) patients had periods of abnormal COPI for 7.81 hours (3.38 hours) either at hypotension (median <45 mm Hg) or hypertension (median >90 mm Hg) or both. Overall, COPI became significantly lower over time, suggesting improved autoregulatory status during the 48 postoperative hours. All of the demographic and perioperative variables were significantly associated with COPI, which in turn was associated with the degree of brain injuries and early outcomes. Conclusions Children with congenital heart disease following cardiac surgery often have disturbed autoregulation. Cerebral autoregulation is at least partly the underlying mechanism of brain injury in those children. Careful clinical management to manipulate the related and modifiable factors, particularly arterial blood pressure, may help to maintain adequate cerebral perfusion and reduce brain injury early after cardiopulmonary bypass surgery. Further studies are warranted to determine the significance of impaired cerebral autoregulation in relation to long-term neurodevelopment outcomes.

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

Background Infants with congenital heart disease (CHD) are at risk for white matter injury (WMI) before neonatal heart surgery. Better knowledge of the causes of preoperative WMI may provide insights into interventions that improve neurodevelopmental outcomes in these patients. Methods and Results A prospective single-center study of preoperative WMI in neonates with CHD recorded data on primary cardiac diagnosis, maternal-fetal environment (MFE), delivery type, subject anthropometrics, and preoperative care. Total maturation score and WMI were assessed, and stepwise logistic regression modeling selected risk factors for WMI. Among subjects with severe CHD (n=183) who received a preoperative brain magnetic resonance imaging, WMI occurred in 40 (21.9%) patients. WMI prevalence (21.4%-22.1%) and mean volumes (119.7-160.4 mm3) were similar across CHD diagnoses. Stepwise logistic regression selected impaired MFE (odds ratio [OR], 2.85 [95% CI, 1.29-6.30]), male sex (OR, 2.27 [95% CI, 1.03-5.36]), and older age at surgery/magnetic resonance imaging (OR, 1.20 per day [95% CI, 1.03-1.41]) as risk factors for preoperative WMI and higher total maturation score values (OR, 0.65 per unit increase [95% CI, 0.43-0.95]) as protective. A quarter (24.6%; n=45) of subjects had ≥1 components of impaired MFE (gestational diabetes [n=12; 6.6%], gestational hypertension [n=11; 6.0%], preeclampsia [n=2; 1.1%], tobacco use [n=9; 4.9%], hypothyroidism [n=6; 3.3%], and other [n=16; 8.7%]). In a subset of 138 subjects, an exploratory analysis of additional MFE-related factors disclosed other potential risk factors for WMI. Conclusions This study is the first to identify impaired MFE as an important risk factor for preoperative WMI. Vulnerability to preoperative WMI was shared across CHD diagnoses.

Radiographic and histologic characterisation of white matter injury in a sheep model of CHD

Nearly one in five children with CHD is born with white matter injury that can be recognised on postnatal MRI by the presence of T1 hyperintense lesions. This pattern of white matter injury is known to portend poor neurodevelopmental outcomes, but the exact aetiology and histologic characterisation of these lesions have never been described. A fetal sheep was cannulated at gestational age 110 days onto a pumpless extracorporeal oxygenator via the umbilical vessels and supported in a fluid environment for 14.5 days. The fetus was supported under hypoxic conditions (mean oxygen delivery 16 ml/kg/day) to simulate the in utero conditions of CHD. At necropsy, the brain was fixed, imaged with MRI, and then stained to histologically identify areas of injury. Under hypoxemic in utero conditions, the fetus developed a T1 hyperintense lesion in its right frontal lobe. Histologically, this lesion was characterised by microvascular proliferation and astrocytosis without gliosis. These findings may provide valuable insight into the aetiology of white matter injury in neonates with CHD.

Continuous electroencephalography (cEEG) in infants with congenital heart disease (CHD)

BACKGROUND

Neonates with congenital heart disease (CHD) undergoing cardiopulmonary bypass (CPB) surgery have increased risk of impaired neurodevelopmental outcomes secondary to brain injury. This study aims to characterize pre- and post-operative continuous EEG (cEEG) patterns to detect abnormal cerebral activity in infants with CHD and investigate whether an association exists between the degree of encephalopathy in pre- and post-operative cEEG.

METHODS

This retrospective cohort study conducted between 2010 and 2018 at a tertiary hospital in Cleveland, OH included infants with CHD with cEEG monitoring, who underwent CPB surgery within first 6 months of life.

RESULTS

Study included 77 patients, of which 61% were males who were operated at median age 6 days. Pre-operatively, 69% and 87% had normal cEEG and sleep-wake cycles, respectively. Post-operatively, 80% had abnormal cEEG. Longer circulatory arrest time and CPB were associated with lack of continuity (p 0.011), excessive discontinuity (p 0.007) and prolonged inter-burst interval (IBI) duration (p value < 0.001). A significant association existed between severity of encephalopathy in immediate and 24-h post-operative period (p value < 0.001).

CONCLUSIONS

More than 80% of neonates with CHD have abnormal post-operative EEG. Longer circulatory arrest time and CPB were associated with lack of continuity, excessive discontinuity, and prolonged IBI duration on post-operative EEG.

IMPACT

This study shows that majority of neonates with congenital heart disease (CHD) have normal pre-operative EEG with a continuous background and normal sleep-wake cycles. Also, 80% of neonates had abnormal post-operative EEG. Longer duration of arrest time and bypass time was associated with lack of continuity, excessive discontinuity, and prolonged IBI duration during post-operative EEG monitoring. These findings will help clinicians when counseling parents in the intensive care unit, risk stratification, and long-term neurodevelopmental monitoring in these high-risk patients.

Neuromonitoring, neuroimaging, and neurodevelopmental follow-up practices in neonatal congenital heart disease: a European survey

BACKGROUND

Brain injury and neurodevelopmental impairment remain a concern in children with complex congenital heart disease (CHD). A practice guideline on neuromonitoring, neuroimaging, and neurodevelopmental follow-up in CHD patients undergoing cardiopulmonary bypass surgery is lacking. The aim of this survey was to systematically evaluate the current practice in centers across Europe.

METHODS

An online-based structured survey was sent to pediatric cardiac surgical centers across Europe between April 2019 and June 2020. Results were summarized by descriptive statistics.

RESULTS

Valid responses were received by 25 European centers, of which 23 completed the questionnaire to the last page. Near-infrared spectroscopy was the most commonly used neuromonitoring modality used in 64, 80, and 72% preoperatively, intraoperatively, and postoperatively, respectively. Neuroimaging was most commonly performed by means of cranial ultrasound in 96 and 84% preoperatively and postoperatively, respectively. Magnetic resonance imaging was obtained in 72 and 44% preoperatively and postoperatively, respectively, but was predominantly reserved for clinically symptomatic patients (preoperatively 67%, postoperatively 64%). Neurodevelopmental follow-up was implemented in 40% of centers and planned in 24%.

CONCLUSIONS

Heterogeneity in perioperative neuromonitoring and neuroimaging practice in CHD in centers across Europe is large. The need for neurodevelopmental follow-up has been recognized. A clear practice guideline is urgently needed.

IMPACT

There is large heterogeneity in neuromonitoring, neuroimaging, and neurodevelopmental follow-up practices among European centers caring for neonates with complex congenital heart disease. This study provides a systematic evaluation of the current neuromonitoring, neuroimaging, and neurodevelopmental follow-up practice in Europe. The results of this survey may serve as the basis for developing a clear practice guideline that could help to early detect and prevent neurological and neurodevelopmental sequelae in neonates with complex congenital heart disease.

Perioperative Course and Socioeconomic Status Predict Long-Term Neurodevelopment Better Than Perioperative Conventional Neuroimaging in Children with Congenital Heart Disease

OBJECTIVE

The objective of the study was to compare the use of neonatal conventional brain magnetic resonance imaging (MRI) with that of clinical factors and socioeconomic status (SES) to predict long-term neurodevelopment in children with severe congenital heart disease (CHD).

STUDY DESIGN

In this prospective cohort study, perioperative MRIs were acquired in 57 term-born infants with CHD undergoing cardiopulmonary bypass surgery during their first year of life. Total brain volume (TBV) was measured using an automated method. Brain injury severity (BIS) was assessed by an established scoring system. The neurodevelopmental outcome was assessed at 6 years using standardized test batteries. A multiple linear regression model was used for cognitive and motor outcomes with postoperative TBV, perioperative BIS, CHD complexity, length of hospital stay, and SES as covariates.

RESULTS

CHD diagnoses included univentricular heart defect (n = 15), transposition of the great arteries (n = 33), and acyanotic CHD (n = 9). Perioperative moderate-to-severe brain injury was detected in 15 (26%) patients. The total IQ was similar to test norms (P = .11), whereas the total motor score (P < .001) was lower. Neither postoperative TBV nor perioperative BIS predicted the total IQ, but SES (P < .001) and longer hospital stay (P = .004) did. No factor predicted the motor outcome.

CONCLUSION

Although the predictive value of neonatal conventional MRIs for long-term neurodevelopment is low, duration of hospital stay and SES better predict the outcome in this CHD sample. These findings should be considered in initiating early therapeutic support.

Clinical factors associated with microstructural connectome related brain dysmaturation in term neonates with congenital heart disease

Objective

Term congenital heart disease (CHD) neonates display abnormalities of brain structure and maturation, which are possibly related to underlying patient factors, abnormal physiology and perioperative insults. Our primary goal was to delineate associations between clinical factors and postnatal brain microstructure in term CHD neonates using diffusion tensor imaging (DTI) magnetic resonance (MR) acquisition combined with complementary data-driven connectome and seed-based tractography quantitative analyses. Our secondary goal was to delineate associations between mild dysplastic structural brain abnormalities and connectome and seed-base tractography quantitative analyses. These mild dysplastic structural abnormalities have been derived from prior human infant CHD MR studies and neonatal mouse models of CHD that were collectively used to calculate to calculate a brain dysplasia score (BDS) that included assessment of subcortical structures including the olfactory bulb, the cerebellum and the hippocampus.

Methods

Neonates undergoing cardiac surgery for CHD were prospectively recruited from two large centers. Both pre- and postoperative MR brain scans were obtained. DTI in 42 directions was segmented into 90 regions using a neonatal brain template and three weighted methods. Clinical data collection included 18 patient-specific and 9 preoperative variables associated with preoperative scan and 6 intraoperative (e.g., cardiopulmonary bypass and deep hypothermic circulatory arrest times) and 12 postoperative variables associated with postoperative scan. We compared patient specific and preoperative clinical factors to network topology and tractography alterations on a preoperative neonatal brain MRI, and intra and postoperative clinical factors to network topology alterations on postoperative neonatal brain MRI. A composite BDS was created to score abnormal findings involving the cerebellar hemispheres and vermis, supratentorial extra-axial fluid, olfactory bulbs and sulci, hippocampus, choroid plexus, corpus callosum, and brainstem. The neuroimaging outcomes of this study included (1) connectome metrics: cost (number of connections) and global/nodal efficiency (network integration); (2) seed based tractography methods of fractional anisotropy (FA), radial diffusivity, and axial diffusivity. Statistics consisted of multiple regression with false discovery rate correction (FDR) comparing the clinical risk factors and BDS (including subcortical components) as predictors/exposures and the global connectome metrics, nodal efficiency, and seed based- tractography (FA, radial diffusivity, and axial diffusivity) as neuroimaging outcome measures.

Results

A total of 133 term neonates with complex CHD were prospectively enrolled and 110 had analyzable DTI. Multiple patient-specific factors including d-transposition of the great arteries (d-TGA) physiology and severity of impairment of fetal cerebral substrate delivery (i.e., how much the CHD lesion alters typical fetal circulation such that the highest oxygen and nutrient rich blood from the placenta are not directed toward the fetal brain) were predictive of preoperative reduced cost (p < 0.0073) and reduced global/nodal efficiency (p < 0.03). Cardiopulmonary bypass time predicted postoperative reduced cost (p < 0.04) and multiple postoperative factors [extracorporeal membrane oxygenation (ECMO), seizures and cardiopulmonary resuscitation (CPR)] were predictive of postoperative reduced cost and reduced global/nodal efficiency (p < 0.05). Anthropometric measurements (weight, length, and head size) predicted tractography outcomes. Total BDS was not predictive of brain network topology. However, key subcortical components of the BDS score did predict key global and nodal network topology: abnormalities of the cerebellum predicted reduced cost (p < 0.0417) and of the hippocampus predicted reduced global efficiency (p < 0.0126). All three subcortical structures predicted unique alterations of nodal efficiency (p < 0.05), including hippocampal abnormalities predicting widespread reduced nodal efficiency in all lobes of the brain, cerebellar abnormalities predicting increased prefrontal nodal efficiency, and olfactory bulb abnormalities predicting posterior parietal-occipital nodal efficiency.

Conclusion

Patient-specific (d-TGA anatomy, preoperative impairment of fetal cerebral substrate delivery) and postoperative (e.g., seizures, need for ECMO, or CPR) clinical factors were most predictive of diffuse postnatal microstructural dysmaturation in term CHD neonates. Anthropometric measurements (weight, length, and head size) predicted tractography outcomes. In contrast, subcortical components (cerebellum, hippocampus, olfactory) of a structurally based BDS (derived from CHD mouse mutants), predicted more localized and regional postnatal microstructural differences. Collectively, these findings suggest that brain DTI connectome and seed-based tractography are complementary techniques which may facilitate deciphering the mechanistic relative contribution of clinical and genetic risk factors related to poor neurodevelopmental outcomes in CHD.

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.

Evaluation and Management of Noncardiac Comorbidities in Children With Congenital Heart Disease

Outcomes for patients with neonatal heart disease are affected by numerous noncardiac and genetic factors. These can include neonatal concerns, such as prematurity and low birth weight, and congenital anomalies, such as airway, pulmonary, gastrointestinal, and genitourinary anomalies, and genetic syndromes. This section will serve as a summary of these issues and how they may affect the evaluation and management of a neonate with heart disease. These noncardiac factors are heavily influenced by conditions common to neonatologists, making a strong argument for multidisciplinary care with neonatologists, cardiologists, surgeons, anesthesiologists, and cardiovascular intensivists. Through this section and this project, we aim to facilitate a comprehensive approach to the care of neonates with congenital heart disease.

Proton magnetic resonance spectroscopy assessment of neonatal brain metabolism during cardiopulmonary bypass surgery

Here, we report on the development and performance of a robust 3-T single-voxel proton magnetic resonance spectroscopy (¹ H MRS) experimental protocol and data analysis pipeline for quantifying brain metabolism during cardiopulmonary bypass (CPB) surgery in a neonatal porcine model, with the overall goal of elucidating primary mechanisms of brain injury associated with these procedures. The specific aims were to assess which metabolic processes can be reliably interrogated by ¹ H MRS on a 3-T clinical scanner and to provide an initial assessment of brain metabolism during deep hypothermia cardiac arrest (DHCA) surgery and recovery. Fourteen neonatal pigs underwent CPB surgery while placed in a 3-T MRI scanner for 18, 28, and 37°C DHCA studies under hyperglycemic, euglycemic, and hypoglycemic conditions. Total imaging times, including baseline measurements, circulatory arrest (CA), and recovery averaged 3 h/animal, during which 30-40 single-voxel ¹ H MRS spectra (sLASER pulse sequence, TR/TE = 2000/30 ms, 64 or 128 averages) were acquired from a 2.2-cc right midbrain voxel. ¹ H MRS at 3 T was able to reliably quantify (1) anaerobic metabolism via depletion of brain glucose and the associated build-up of lactate during CA, (2) phosphocreatine (PCr) to creatine (Cr) conversion during CA and subsequent recovery upon reperfusion, (3) a robust increase in the glutamine-to-glutamate (Gln/Glu) ratio during the post-CA recovery period, and (4) a broadening of the water peak during CA. In vivo ¹ H MRS at 3 T can reliably quantify subtle metabolic brain changes previously deemed challenging to interrogate, including brain glucose concentrations even under hypoglycemic conditions, ATP usage via the conversion of PCr to Cr, and differential changes in Glu and Gln. Observed metabolic changes during CPB surgery of a neonatal porcine model provide new insights into possible mechanisms for prevention of neuronal injury.

Analyzing Continuous Physiologic Data to Find Hemodynamic Signatures Associated With New Brain Injury After Congenital Heart Surgery

Continuous data capture technology is becoming more common. Establishing analytic approaches for continuous data could aid in understanding the relationship between physiology and clinical outcomes.

Paediatric brain MRI findings following congenital heart surgery: a systematic review

OBJECTIVE

This systematic review aimed to establish the relative incidence of new postoperative brain MRI findings following paediatric congenital cardiac surgery.

DESIGN

To distinguish perioperative changes from pre-existing MR findings, our systematic search strategy focused on identifying original research studies reporting both presurgery and postsurgery brain MRI scans. Patient demographics, study methods and brain MR findings were extracted.

RESULTS

Twenty-one eligible publications, including two case-control and one randomised controlled trial, were identified. Pre-existing brain MRI findings were noted in 43% (513/1205) of neonates prior to surgery, mainly white matter injuries (WMI). Surgery was performed at a median age of 8 days with comparison of preoperative and postoperative MR scans revealing additional new postoperative findings in 51% (550/1075) of patients, mainly WMI. Four studies adopted a brain injury scoring system, but the majority did not indicate the severity or time course of findings. In a subgroup analysis, approximately 32% of patients with pre-existing lesions went on to develop additional new lesions postsurgery. Pre-existing findings were not found to confer a higher risk of acquiring brain lesions postoperatively. No evidence was identified linking new MR findings with later neurodevelopmental delay.

CONCLUSION

This systematic review suggests that surgery approximately doubles the number of patients with new brain lesions.

Reduced Cerebellar Volume in Term Infants with Complex Congenital Heart Disease: Correlation with Postnatal Growth Measurements

Aberrant cerebellar development and the associated neurocognitive deficits has been postulated in infants with congenital heart disease (CHD). Our objective is to investigate the effect of postnatal head and somatic growth on cerebellar development in neonates with CHD. We compared term-born neonates with a history of CHD with a cohort of preterm-born neonates, two cohorts at similar risk for neurodevelopment impairment, in order to determine if they are similarly affected in the early developmental period. Study Design: 51 preterms-born healthy neonates, 62 term-born CHD neonates, and 54 term-born healthy neonates underwent a brain MRI with volumetric imaging. Cerebellar volumes were extracted through an automated segmentation pipeline that was developed in-house. Volumes were correlated with clinical growth parameters at both the birth and time of MRI. Results: The CHD cohort showed significantly lower cerebellar volumes when compared with both the control (p < 0.015) and preterm (p < 0.004) groups. Change in weight from birth to time of MRI showed a moderately strong correlation with cerebellar volume at time of MRI (r = 0.437, p < 0.002) in the preterms, but not in the CHD neonates (r = 0.205, p < 0.116). Changes in birth length and head circumference showed no significant correlation with cerebellar volume at time of MRI in either cohort. Conclusions: Cerebellar development in premature-born infants is associated with change in birth weight in the early post-natal period. This association is not observed in term-born neonates with CHD, suggesting differential mechanisms of aberrant cerebellar development in these perinatal at-risk populations.

Detection of Cerebral High-Intensity Transient Signals by NeoDoppler during Cardiac Catheterization and Cardiac Surgery in Infants

There is a risk of gaseous and solid micro-embolus formation during transcatheter cardiac interventions and surgery in children with congenital heart disease (CHD). Our aim was to study the burden of high-intensity transient signals (HITS) during these procedures in infants. We used a novel color M-mode Doppler (CMD) technique by NeoDoppler, a non-invasive ultrasound system based on plane wave transmissions for transfontanellar continuous monitoring of cerebral blood flow in infants. The system displays CMD with 24 sample volumes and a Doppler spectrogram. Infants with CHD undergoing transcatheter interventions (n = 15) and surgery (n = 13) were included. HITS were manually detected based on an "embolic signature" in the CMD with corresponding intensity increase in the Doppler spectrogram. Embolus-to-blood ratio (EBR) defined HITS size. A total of 1169 HITS with a median EBR of 9.74 dB (interquartile range [IQR]: 5.10-15.80 dB) were detected. The median number of HITS in the surgery group was 45 (IQR: 11-150), while in the transcatheter group the median number was 12 (IQR: 7-24). During cardiac surgery, the highest number of HITS per hour was seen from initiation of cardiopulmonary bypass to aortic X-clamp. In this study we detected frequent HITS and determined the feasibility of using NeoDoppler monitoring for HITS detection.

In infants with congenital heart disease autonomic dysfunction is associated with pre-operative brain injury

BACKGROUND

Brain injury is a serious and common complication of critical congenital heart disease (CHD). Impaired autonomic development (assessed by heart rate variability (HRV)) is associated with brain injury in other high-risk neonatal populations.

OBJECTIVE

To determine whether impaired early neonatal HRV is associated with pre-operative brain injury in CHD.

METHODS

In infants with critical CHD, we evaluated HRV during the first 24 h of cardiac ICU (CICU) admission using time-domain (RMS 1, RMS 2, and alpha 1) and frequency-domain metrics (LF, nLF, HF, nHF). Pre-operative brain magnetic resonance imaging (MRI) was scored for injury using an established system. Spearman's correlation coefficient was used to determine the association between HRV and pre-operative brain injury.

RESULTS

We enrolled 34 infants with median birth gestational age of 38.8 weeks (IQR 38.1-39.1). Median postnatal age at pre-operative brain MRI was 2 days (IQR 1-3 days). Thirteen infants had MRI evidence of brain injury. RMS 1 and RMS 2 were inversely correlated with pre-operative brain injury.

CONCLUSIONS

Time-domain metrics of autonomic function measured within the first 24 h of admission to the CICU are associated with pre-operative brain injury, and may perform better than frequency-domain metrics under non-stationary conditions such as critical illness.

IMPACT

Autonomic dysfunction, measured by heart rate variability (HRV), in early transition is associated with pre-operative brain injury in neonates with critical congenital heart disease. These data extend our earlier findings by providing further evidence for (i) autonomic dysfunction in infants with CHD, and (ii) an association between autonomic dysfunction and brain injury in critically ill neonates. These data support the notion that further investigation of HRV as a biomarker for brain injury risk is warranted in infants with critical CHD.

Altered myelination in youth born with congenital heart disease

Brain injury and dysmaturation is common in fetuses and neonates with congenital heart disease (CHD) and is hypothesized to result in persistent myelination deficits. This study aimed to quantify and compare myelin content in vivo between youth born with CHD and healthy controls. Youth aged 16 to 24 years born with CHD and healthy age‐ and sex‐matched controls underwent brain magnetic resonance imaging including multicomponent driven equilibrium single pulse observation of T₁ and T₂ (mcDESPOT). Average myelin water fraction (MWF) values for 33 white matter tracts, as well as a summary measure of average white matter MWF, the White Matter Myelination Index, were calculated and compared between groups. Tract‐average MWF was lower throughout the corpus callosum and in many bilateral association tracts and left hemispheric projection tracts in youth with CHD (N = 44) as compared to controls (N = 45). The White Matter Myelination Index was also lower in the CHD group. As such, this study provides specific evidence of widespread myelination deficits in youth with CHD, likely representing a long‐lasting consequence of early‐life brain dysmaturation in this population. This deficient myelination may underlie the frequent neurodevelopmental impairments experienced by CHD survivors and could eventually serve as a biomarker of neuropsychological function.

Dextro-Transposition of Great Arteries and Neurodevelopmental Outcomes: A Review of the Literature

Background: Arterial switch operation (ASO) is the gold-standard surgical approach for dextro-transposition of the great arteries (D-TGA). It is performed during the neonatal period and has almost diminished the previously high mortality rate (from 90% if left untreated to <0.5%). Despite the impressively high survival rates, the surgical procedure itself—along with the chronic post-operative complications and the perinatal impaired cerebral oxygen delivery—introduces multiple and cumulative risk factors for neurodevelopmental impairment. Method: This study is a review of English articles, using PUBMED and applying the following search terms, “transposition of the great arteries”, “neurodevelopment”, “autism”, “cerebral palsy”, and “attention-deficit hyperactivity disorder”. Data were extracted by two authors. Results: Even though general IQ is mainly found within the normal range, D-TGA children and adolescents display reduced performance in the assignments of executive functions, fine motor functions, attention, working memory, visual−spatial skills, and higher-order language skills. Moreover, D-TGA survivors may eventually struggle with inferior academic achievements and psychiatric disorders such as depression, anxiety, and ADHD. Conclusions: The existing literature concerning the neurodevelopment of D-TGA patients suggests impairment occurring during their lifespan. These findings underline the importance of close developmental surveillance so that D-TGA patients can better reach their full potential.

Association of Ongoing Cerebral Oxygen Extraction During Deep Hypothermic Circulatory Arrest With Postoperative Brain Injury

Cardiac surgery utilizing circulatory arrest is most commonly performed under deep hypothermia (∼18°C) to suppress tissue oxygen demand and provide neuroprotection during operative circulatory arrest. Studies investigating the effects of deep hypothermic circulatory arrest (DHCA) on neurodevelopmental outcomes of patients with congenital heart disease give conflicting results. Here, we address these issues by quantifying changes in cerebral oxygen saturation, blood flow, and oxygen metabolism in neonates during DHCA and investigating the association of these changes with postoperative brain injury. Neonates with critical congenital heart disease undergoing DHCA were recruited for continuous intraoperative monitoring of cerebral oxygen saturation (ScO₂) and an index of cerebral blood flow (CBF_i) using 2 noninvasive optical techniques, diffuse optical spectroscopy (DOS) and diffuse correlation spectroscopy (DCS). Pre- and postoperative brain magnetic resonance imaging (MRI) was performed to detect white matter injury (WMI). Fifteen neonates were studied, and 11/15 underwent brain MRI. During DHCA, ScO₂ decreased exponentially in time with a median decay rate of -0.04 min^-1. This decay rate was highly variable between subjects. Subjects who had larger decreases in ScO₂ during DHCA were more likely to have postoperative WMI (P = 0.02). Cerebral oxygen extraction persists during DHCA and varies widely from patient-to-patient. Patients with a higher degree of oxygen extraction during DHCA were more likely to show new WMI in postoperative MRI. These findings suggest cerebral oxygen extraction should be monitored during DHCA to identify patients at risk for hypoxic-ischemic injury, and that current commercial cerebral oximeters may underestimate cerebral oxygen extraction.

Brain MRI Radiomics Analysis of School-Aged Children with Tetralogy of Fallot

Introduction

Radiomics could be potential imaging biomarkers by capturing and analyzing the features. Children and adolescents with CHD have worse neurodevelopmental and functional outcomes compared with their peers. Early diagnosis and intervention are the necessity to improve neurological outcomes in CHD patients.

Methods

School-aged TOF patients and their healthy peers were recruited for MRI and neurodevelopmental assessment. LASSO regression was used for dimension reduction. ROC curve graph showed the performance of the model.

Results

Six related features were finally selected for modeling. The final model AUC was 0.750. The radiomics features can be potential significant predictors for neurodevelopmental diagnoses.

Conclusion

The radiomics on the conventional MRI can help predict the neurodevelopment of school-aged children and provide parents with rehabilitation advice as early as possible.

A Uniform Description of Perioperative Brain MRI Findings in Infants with Severe Congenital Heart Disease: Results of a European Collaboration

BACKGROUND AND PURPOSE

A uniform description of brain MR imaging findings in infants with severe congenital heart disease to assess risk factors, predict outcome, and compare centers is lacking. Our objective was to uniformly describe the spectrum of perioperative brain MR imaging findings in infants with congenital heart disease.

MATERIALS AND METHODS

Prospective observational studies were performed at 3 European centers between 2009 and 2019. Brain MR imaging was performed preoperatively and/or postoperatively in infants with transposition of the great arteries, single-ventricle physiology, or left ventricular outflow tract obstruction undergoing cardiac surgery within the first 6 weeks of life. Brain injury was assessed on T1, T2, DWI, SWI, and MRV. A subsample of images was assessed jointly to reach a consensus.

RESULTS

A total of 348 MR imaging scans (180 preoperatively, 168 postoperatively, 146 pre- and postoperatively) were obtained in 202 infants. Preoperative, new postoperative, and cumulative postoperative white matter injury was identified in 25%, 30%, and 36%; arterial ischemic stroke, in 6%, 10%, and 14%; hypoxic-ischemic watershed injury in 2%, 1%, and 1%; intraparenchymal cerebral hemorrhage, in 0%, 4%, and 5%; cerebellar hemorrhage, in 6%, 2%, and 6%; intraventricular hemorrhage, in 14%, 6%, and 13%; subdural hemorrhage, in 29%, 17%, and 29%; and cerebral sinovenous thrombosis, in 0%, 10%, and 10%, respectively.

CONCLUSIONS

A broad spectrum of perioperative brain MR imaging findings was found in infants with severe congenital heart disease. We propose an MR imaging protocol including T1-, T2-, diffusion-, and susceptibility-weighted imaging, and MRV to identify ischemic, hemorrhagic, and thrombotic lesions observed in this patient group.

Contrast-enhanced ultrasound of the pediatric brain

Brain contrast-enhanced ultrasound (CEUS) is an emerging application that can complement gray-scale US and yield additional insights into cerebral flow dynamics. CEUS uses intravenous injection of ultrasound contrast agents (UCAs) to highlight tissue perfusion and thus more clearly delineate cerebral pathologies including stroke, hypoxic-ischemic injury and focal lesions such as tumors and vascular malformations. It can be applied not only in infants with open fontanelles but also in older children and adults via a transtemporal window or surgically created acoustic window. Advancements in CEUS technology and post-processing methods for quantitative analysis of UCA kinetics further elucidate cerebral microcirculation. In this review article we discuss the CEUS examination protocol for brain imaging in children, current clinical applications and future directions for research and clinical uses of brain CEUS.

Thrombosis Prevention and Anticoagulation Management in the Pediatric Patient with Congenital Heart Disease

Thrombosis is one of the most frequent complications affecting children with congenital heart disease (CHD). Palliative and reparative cardiac surgeries are some of the main players contributing to the thrombosis risk in this patient population. Additional risk factors related to the CHD itself (e.g., cardiac dysfunction, arrhythmias, and polycythemia in cyanotic cardiac disorders) can contribute to thrombogenicity alone or combined with other factors. Thrombotic complications have been recognized as a significant cause of morbidity and mortality in this patient population. Here, we provide an overview of the pathophysiology and risk factors for thrombosis as well as the indications for and use of different anticoagulation, antiplatelet, and thrombolytic agents. In addition, we describe some of most common thrombotic complications and their management in the pediatric CHD population.

Abnormal Left-Hemispheric Sulcal Patterns in Adults With Simple Congenital Heart Defects Repaired in Childhood

Background

Children operated on for a simple congenital heart defect (CHD) are at risk of neurodevelopmental abnormalities. Abnormal cortical development and folding have been observed in fetuses with CHD. We examined whether sulcal folding patterns in adults operated on for simple CHD in childhood differ from those of healthy controls, and whether such differences are associated with neuropsychological outcomes.

Methods and Results

Patients (mean age, 24.5 years) who underwent childhood surgery for isolated atrial septal defect (ASD; n=33) or ventricular septal defect (VSD; n=30) and healthy controls (n=37) were enrolled. Sulcal pattern similarity to healthy controls was determined using magnetic resonance imaging and looking at features of sulcal folds, their intersulcal relationships, and sulcal graph topology. The sulcal pattern similarity values were tested for associations with comprehensive neuropsychological scores. Patients with both ASD and VSD had decreased sulcal pattern similarity in the left hemisphere compared with controls. The differences were found in the left temporal lobe in the ASD group and in the whole left hemisphere in the VSD group (P=0.033 and P=0.039, respectively). The extent of abnormal left hemispheric sulcal pattern similarity was associated with worse neuropsychological scores (intelligence, executive function, and visuospatial abilities) in the VSD group, and special educational support in the ASD group.

Conclusions

Adults who underwent surgery for simple CHD in childhood display altered left hemisphere sulcal folding patterns, commensurate with neuropsychological scores for patients with VSD and special educational support for ASD. This may indicate that simple CHD affects early brain development.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03871881.

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.

Early-Emerging Sulcal Patterns Are Atypical in Fetuses with Congenital Heart Disease

Fetuses with congenital heart disease (CHD) have third trimester alterations in cortical development on brain magnetic resonance imaging (MRI). However, the intersulcal relationships contributing to global sulcal pattern remain unknown. This study applied a novel method for examining the geometric and topological relationships between sulci to fetal brain MRIs from 21-30 gestational weeks in CHD fetuses (n = 19) and typically developing (TD) fetuses (n = 17). Sulcal pattern similarity index (SI) to template fetal brain MRIs was determined for the position, area, and depth for corresponding sulcal basins and intersulcal relationships for each subject. CHD fetuses demonstrated altered global sulcal patterns in the left hemisphere compared with TD fetuses (TD [SI, mean ± SD]: 0.822 ± 0.023, CHD: 0.795 ± 0.030, P = 0.002). These differences were present in the earliest emerging sulci and were driven by differences in the position of corresponding sulcal basins (TD: 0.897 ± 0.024, CHD: 0.878 ± 0.019, P = 0.006) and intersulcal relationships (TD: 0.876 ± 0.031, CHD: 0.857 ± 0.018, P = 0.033). No differences in cortical gyrification index, mean curvature, or surface area were present. These data suggest our methods may be more sensitive than traditional measures for evaluating cortical developmental alterations early in gestation.

Abnormal Microstructural Development of the Cerebral Cortex in Neonates With Congenital Heart Disease Is Associated With Impaired Cerebral Oxygen Delivery

Background Abnormal macrostructural development of the cerebral cortex has been associated with hypoxia in infants with congenital heart disease ( CHD ). Animal studies have suggested that hypoxia results in cortical dysmaturation at the cellular level. New magnetic resonance imaging techniques offer the potential to investigate the relationship between cerebral oxygen delivery and cortical microstructural development in newborn infants with CHD . Methods and Results We measured cortical macrostructural and microstructural properties in 48 newborn infants with serious or critical CHD and 48 age-matched healthy controls. Cortical volume and gyrification index were calculated from high-resolution structural magnetic resonance imaging. Neurite density and orientation dispersion indices were modeled using high-angular-resolution diffusion magnetic resonance imaging. Cerebral oxygen delivery was estimated in infants with CHD using phase contrast magnetic resonance imaging and preductal pulse oximetry. We used gray matter-based spatial statistics to examine voxel-wise group differences in cortical microstructure. Microstructural development of the cortex was abnormal in 48 infants with CHD , with regions of increased fractional anisotropy and reduced orientation dispersion index compared with 48 healthy controls, correcting for gestational age at birth and scan (family-wise error corrected for multiple comparisons at P<0.05). Regions of reduced cortical orientation dispersion index in infants with CHD were related to impaired cerebral oxygen delivery ( R²=0.637; n=39). Cortical orientation dispersion index was associated with the gyrification index ( R²=0.589; P<0.001; n=48). Conclusions This study suggests that the primary component of cerebral cortex dysmaturation in CHD is impaired dendritic arborization, which may underlie abnormal macrostructural findings reported in this population, and that the degree of impairment is related to reduced cerebral oxygen delivery.

Benefits of progesterone on brain immaturity and white matter injury induced by chronic hypoxia in neonatal rats

OBJECTIVES

This study aims to evaluate the protective effects of progesterone on white matter injury and brain immaturity in neonatal rats with chronic hypoxia.

METHODS

Three-day old Sprague-Dawley rats were randomly divided into 3 groups: (1) control (n = 48), rats were exposed to normoxia (fraction of inspired oxygen: 21% ± 0%); (2) chronic hypoxia (n = 48), rats were exposed to hypoxia (fraction of inspired oxygen: 10.5% ± 1.0%); and (3) progesterone (n = 48), rats were exposed to hypoxia and administrated with progesterone (8 mg/kg/d). Hematoxylin-eosin staining, immunohistochemistry, real-time quantitative polymerase chain reaction, and Western blot analyses were compared on postnatal day 14 in different groups. Motor skill and coordination abilities of rats were assessed via rotation experiments.

RESULTS

Increased brain weights (P < .05), narrowed ventricular sizes (P < .01), and rotarod experiment scores (P < .01) were better in the progesterone group than in the chronic hypoxia group. The number of mature oligodendrocytes and myelin basic protein expression increased in the progesterone group compared with the chronic hypoxia group (P < .01). The polarization of M1 microglia cells in the corpus callosum of chronic hypoxia-induced hypomyelination rats was significantly increased, whereas there were fewer M2 microglia cells. Conversely, progesterone therapy had an opposite effect and caused an increase in M2 microglia polarization versus a reduction in M1 microglia cells.

CONCLUSIONS

Progesterone could prevent white matter injury and improve brain maturation in a neonatal hypoxic rat model; this may be associated with inducing a switch from M1 to M2 in microglia.

Abnormal Left-Hemispheric Sulcal Patterns Correlate with Neurodevelopmental Outcomes in Subjects with Single Ventricular Congenital Heart Disease

Neurodevelopmental abnormalities are the most common noncardiac complications in patients with congenital heart disease (CHD). Prenatal brain abnormalities may be due to reduced oxygenation, genetic factors, or less commonly, teratogens. Understanding the contribution of these factors is essential to improve outcomes. Because primary sulcal patterns are prenatally determined and under strong genetic control, we hypothesized that they are influenced by genetic variants in CHD. In this study, we reveal significant alterations in sulcal patterns among subjects with single ventricle CHD (n = 115, 14.7 ± 2.9 years [mean ± standard deviation]) compared with controls (n = 45, 15.5 ± 2.4 years) using a graph-based pattern-analysis technique. Among patients with CHD, the left hemisphere demonstrated decreased sulcal pattern similarity to controls in the left temporal and parietal lobes, as well as the bilateral frontal lobes. Temporal and parietal lobes demonstrated an abnormally asymmetric left-right pattern of sulcal basin area in CHD subjects. Sulcal pattern similarity to control was positively correlated with working memory, processing speed, and executive function. Exome analysis identified damaging de novo variants only in CHD subjects with more atypical sulcal patterns. Together, these findings suggest that sulcal pattern analysis may be useful in characterizing genetically influenced, atypical early brain development and neurodevelopmental risk in subjects with CHD.

Neurologic Injury in Neonates Undergoing Cardiac Surgery

Neurodevelopmental outcomes after neonatal congenital heart surgery are significantly influenced by brain injury detectable by MRI imaging techniques. This brain injury can occur in the prenatal and postnatal periods even before cardiac surgery. Given the significant incidence of new MRI brain injury after cardiac surgery, much work is yet to be done on strategies to detect, prevent, and treat brain injury in the neonatal period in order to optimize longer-term neurodevelopmental outcomes.

Associations of Neonatal Noncardiac Surgery with Brain Structure and Neurodevelopment: A Prospective Case-Control Study

OBJECTIVE

To examine the associations of neonatal noncardiac surgery with newborn brain structure and neurodevelopment at 2 years of age.

STUDY DESIGN

Infants requiring neonatal noncardiac surgery for congenital diaphragmatic hernia, esophageal atresia, or anterior abdominal wall defect were compared with infants who did not require surgery, matched for sex, gestation at birth, and postmenstrual age at magnetic resonance imaging. Cerebral magnetic resonance imaging was performed at a mean (SD) postmenstrual age of 41.6 (1.7) weeks. Images were assessed qualitatively for brain maturation and injury and quantitatively for measures of brain size, cerebrospinal fluid spaces, and global abnormality. Neurodevelopment was then assessed at 2 years using the Bayley Scales of Infant and Toddler Development, 3rd edition.

RESULTS

Infants requiring surgery (n = 39) were 5.9 times (95% CI, 1.9-19.5; P < .01) more likely to have delayed gyral maturation and 9.8 times (95% CI, 1.2-446; P = .01) more likely to have white matter signal abnormalities compared with controls (n = 39). Cases were more likely to have higher global abnormality scores, smaller biparietal diameters, and larger ventricular sizes than controls. Infants who had surgery had lower mean composite scores in the language (mean difference, -12.5; 95% CI, -22.4 to -2.7) and motor domains (mean difference, -13.4; 95% CI, -21.1 to -5.6) compared with controls.

CONCLUSIONS

Infants requiring neonatal noncardiac surgery have smaller brains with more abnormalities compared with matched controls and have associated neurodevelopmental impairment at 2 years of age. Prospective studies with preoperative and postoperative imaging would assist in determining the timing of brain injury.

Therapeutic Hypothermia After Perinatal Asphyxia in Infants With Severe, Ductal-Dependent Congenital Heart Disease

OBJECTIVES

Patients with severe congenital heart disease and cardiac anomalies such as restrictive foramen ovale, intact atrial septum, or narrowing of ductus arteriosus are at risk for perinatal asphyxia, leading to hypoxic-ischemic encephalopathy. We hypothesize that therapeutic hypothermia can be applied to these patients and seek to investigate feasibility and safety of this method.

DESIGN

A retrospective observational study.

SETTING

The Department of Neonatology of Charité, University Hospital, Berlin, Germany.

PATIENTS

Newborns with severe congenital heart disease and perinatal asphyxia were retrospectively analyzed over a 6-year period.

INTERVENTIONS

Application of therapeutic hypothermia.

MEASUREMENTS AND MAIN RESULTS

Ten patients with perinatal asphyxia were enrolled in this study. All patients received low-dose prostaglandin E1 for ductal maintenance. Three patients without evidence for hypoxic-ischemic encephalopathy did not receive therapeutic hypothermia. One patient died at the age of 15 hours, and therapeutic hypothermia was discontinued after 19 hours in another patient with severe arterial hypotension. Adverse effects during hypothermia included respiratory insufficiency (100%), arterial hypotension (71%), the need for inotropic support (71%), and pulmonary hypertension (43%), the latter associated with prolonged postoperative inotropic support. No neurologic complications occurred before or after the surgery. Operative outcome of surviving patients was excellent. Early brain MRI scans were suggestive of good neurodevelopmental prognosis for most patients.

CONCLUSIONS

Therapeutic hypothermia can be applied to patients with severe congenital heart disease and hypoxic-ischemic encephalopathy. Low-dose prostaglandin E1 infusions are safe for ductal maintenance during cooling, but cardiopulmonary adverse effects should be anticipated.

Perioperatively Inhaled Hydrogen Gas Diminishes Neurologic Injury Following Experimental Circulatory Arrest in Swine

This study used a swine model of mildly hypothermic prolonged circulatory arrest and found that the addition of 2.4% inhaled hydrogen gas to inspiratory gases during and after the ischemic insult significantly decreased neurologic and renal injury compared with controls. With proper precautions, inhalational hydrogen may be administered safely through conventional ventilators and may represent a complementary therapy that can be easily incorporated into current workflows. In the future, inhaled hydrogen may diminish the sequelae of ischemia that occurs in congenital heart surgery, cardiac arrest, extracorporeal life-support events, acute myocardial infarction, stroke, and organ transplantation.

Hybrid procedure of right ventricle outflow tract stenting in small infants with pulmonary atresia and ventricular septal defect: early and mid-term results from a single centre

IntroductionPulmonary atresia, ventricular septal defect, major aorto-pulmonary collateral arteries, and pulmonary arteries hypoplasia are rare and complex congenital defects that require early interventions to relieve cyanosis and enhance the growth of native pulmonary arteries. The treatment of these patients is still controversial. Surgical techniques require cardiopulmonary bypass which is poorly tolerated by small infants. Percutaneous techniques such as radiofrequency perforation can be challenging. The hybrid technique consists of perventricular stenting of the right ventricle outflow tract through medial sternotomy, to restore native pulmonary flow.

METHODS

We retrospectively reviewed the cardiovascular database of our centre in order to analyse our experience in hybrid procedure. We detected six patients who underwent hybrid first approach between November 2007 and December 2015. We report our early results and mid-term outcomes.

RESULTS

Median age at the procedure was 26 days, median weight was 3150 g, and median Nakata index was 52 mm2/m2. All procedures were successful except for one: this patient underwent a surgical shunt. No immediate and early deaths or major complications occurred and oxygen saturation levels increased in all the patients. Patients were followed up for a period of 12-103 months, and four of them underwent a procedure of unifocalisation at the mean age of 12.5 months.

CONCLUSIONS

We reported data from the largest series of patients who underwent this hybrid procedure. Our experience demonstrated encouraging results to expand the use of this approach to bridge high-risk patients with diminutive pulmonary arteries to a second step of surgical repair.

White matter injury in term neonates with congenital heart diseases: Topology & comparison with preterm newborns

BACKGROUND

Neonates with congenital heart disease (CHD) are at high risk of punctate white matter injury (WMI) and impaired brain development. We hypothesized that WMI in CHD neonates occurs in a characteristic distribution that shares topology with preterm WMI and that lower birth gestational age (GA) is associated with larger WMI volume.

OBJECTIVE

(1) To quantitatively assess the volume and location of WMI in CHD neonates across three centres. (2) To compare the volume and spatial distribution of WMI between term CHD neonates and preterm neonates using lesion mapping.

METHODS

In 216 term born CHD neonates from three prospective cohorts (mean birth GA: 39 weeks), WMI was identified in 86 neonates (UBC: 29; UCSF: 43; UCZ: 14) on pre- and/or post-operative T1 weighted MRI. WMI was manually segmented and volumes were calculated. A standard brain template was generated. Probabilistic WMI maps (total, pre- and post-operative) were developed in this common space. Using these maps, WMI in the term CHD neonates was compared with that in preterm neonates: 58 at early-in-life (mean postmenstrual age at scan 32.2 weeks); 41 at term-equivalent age (mean postmenstrual age at scan 40.1 weeks).

RESULTS

The total WMI volumes of CHD neonates across centres did not differ (p = 0.068): UBC (median = 84.6 mm3, IQR = 26-174.7 mm3); UCSF (median = 104 mm3, IQR = 44-243 mm3); UCZ (median = 121 mm3, IQR = 68-200.8 mm3). The spatial distribution of WMI in CHD neonates showed strong concordance across centres with predilection for anterior and posterior rather than central lesions. Predominance of anterior lesions was apparent on the post-operative WMI map relative to the pre-operative map. Lower GA at birth predicted an increasing volume of WMI across the full cohort (41.1 mm3 increase of WMI per week decrease in gestational age; 95% CI 11.5-70.8; p = 0.007), when accounting for centre and heart lesion. While WMI in term CHD and preterm neonates occurs most commonly in the intermediate zone/outer subventricular zone there is a paucity of central lesions in the CHD neonates relative to preterms.

CONCLUSIONS

WMI in term neonates with CHD occurs in a characteristic topology. The spatial distribution of WMI in term neonates with CHD reflects the expected maturation of pre-oligodendrocytes such that the central regions are less vulnerable than in the preterm neonates.

S100B and its relation to cerebral oxygenation in neonates and infants undergoing surgery for congenital heart disease

OBJECTIVES

Neonates and infants undergoing surgery for congenital heart disease are at risk for developmental impairment. Hypoxic-ischemic brain injury might be one contributing factor. We aimed to investigate the perioperative release of the astrocyte protein S100B and its relation to cerebral oxygenation.

METHODS

Serum S100B was measured before and 0, 12, 24, and 48 hours after surgery. Cerebral oxygen saturation was derived by near-infrared spectroscopy. S100B reference values based on preoperative samples; concentrations above the 75th percentile were defined as elevated. Patients with elevated S100B at 24 or 48 hours were compared to cases with S100B in the normal range. Neonates (≤28 days) and infants (>28 and ≤365 days) were analyzed separately due to age-dependent release of S100B.

RESULTS

Seventy-four patients underwent 94 surgical procedures (neonates, n = 38; infants, n = 56). S100B concentrations were higher in neonates before and after surgery at all time points (P ≤ .015). Highest values were noticed immediately after surgery. Postoperative S100B was elevated after 15 (40.5%) surgeries in neonates. There was no difference in pre-, intra-, or postoperative cerebral oxygenation. In infants, postoperative S100B was elevated after 23 (41.8%) procedures. Preoperative cerebral oxygen saturations tended to be lower (53 ± 12% vs 59 ± 12%, P = .069) and arterial-cerebral oxygen saturation difference was higher (35 ± 11% vs 28 ± 11%, P = .018) in infants with elevated postoperative S100B. In the early postoperative course, cerebral oxygen saturation was lower (54 ± 13% vs 63 ± 12%, P = .011) and arterial-cerebral oxygen saturation difference was wider (38 ± 11% vs 30 ± 10%, P = .008). Cerebral oxygen saturation was also lower for the entire postoperative course (62 ± 18% vs 67 ± 9%, P = .047).

CONCLUSIONS

Postoperative S100B was elevated in about 40% of neonates and infants undergoing cardiac surgery. Infants with elevated postoperative S100B had impaired perioperative cerebral tissue oxygenation. No relation between S100B and cerebral oxygenation could be demonstrated in neonates.