The relationship of postoperative electrographic seizures to neurodevelopmental outcome at 1 year of age after neonatal and infant cardiac surgery

Postoperative EEG abnormalities in relation to neurodevelopmental outcomes after pediatric cardiac surgery

BACKGROUND

We had reported that postoperative EEG background including sleep-wake cycle (SWC) and discharge (seizures, spikes/sharp waves) abnormalities were significantly correlated with adverse early outcomes in children after cardiac surgery. We aimed to analyze the relations between these EEG abnormalities and neurodevelopmental outcomes at about 2 years after cardiac surgery.

METHODS

We enrolled 121 patients undergoing cardiac surgery at 3.3 months (0.03 ~ 28 months). EEG abnormalities described above during the first postoperative 48 h were evaluated. Griffiths Mental Development Scales-Chinese was used to evaluate the quotients of overall development and 5 subscales of the child's locomotor, language, personal-social, eye-hand coordination and performance skills at 16 ~ 31 months of age.

RESULTS

EEG background abnormalities occurred in 59/121 (48.8%) patients and 33 (55.9%) unrecovered to normal by 48 h. Abnormal SWC occurred in 15 (12.4%) patients and 7 (5.8%) unrecovered to normal by 48 h. EEG seizures occurred in 11 (9.1%) patients with frontal lobe seizures in 4. Spikes/sharp waves occurred in 100 (82.6%). EEG background abnormalities, number of spikes/sharp waves and frontal lobe seizures were significantly associated with neurodevelopmental impairment at about 1 ~ 2 year after surgery (Ps ≤ 0.05).

CONCLUSIONS

Most parameters of EEG abnormalities were significantly associated with neurodevelopmental impairment after cardiac surgery.

IMPACT

Neurodevelopmental impairment in children with congenital heart disease remain poorly understood. Previous studies had reported that either EEG seizures or background abnormalities were associated with worse neurodevelopmental outcomes. Our present study showed that all the EEG background and discharge abnormalities including EEG background, seizures and spikes/sharp waves in the early postoperative period were significantly associated with neurodevelopmental impairment at about 1 ~ 2 years after cardiac surgery. Comprehensive evaluation of early postoperative EEG may provide further insights about postoperative brain injury, its relation with neurodevelopmental impairment, and guide to improve clinical management.

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.

Neurological injury in pediatric heart disease: A review of developmental and acquired risk factors and management considerations

Medical and surgical advancements have improved survival in children with acquired and congenital heart disease (CHD), but the burden of neurological morbidity is high. Brain disorders associated with CHD include white matter injury, stroke, seizure, and neurodevelopmental delays. While genetics and disease-specific factors play a substantial role in early brain injury, therapeutic management of the heart disease intensifies the risk. There is a growing interest in understanding how to reduce brain injury and improve neurodevelopmental outcomes in cardiac diseases. Pediatric neurologists serve a vital role in care teams managing these complex patients, providing interpretation of neuromonitoring and imaging, managing neurologic emergencies, assisting with neuro prognostication, and identifying future research aims.

Perioperative Neuromonitoring in Children with Congenital Heart Disease

Although neonates and children with congenital heart disease are primarily hospitalized for cardiac and pulmonary diseases, they are also at an increased risk for neurologic injury due to both empiric differences that can exist in their nervous systems and acquired injury from cardiopulmonary pathology and interventions. Although early efforts in care focused on survival after reparative cardiac surgery, as surgical and anesthetic techniques have evolved and survival rates accordingly improved, the focus has now shifted to maximizing outcomes among survivors. Children and neonates with congenital heart disease experience seizures and poor neurodevelopmental outcomes at a higher rate than age-matched counterparts. The aim of neuromonitoring is to help clinicians identify patients at highest risk for these outcomes to implement strategies to mitigate these risks and to also help with neuroprognostication after an injury has occurred. The mainstays of neuromonitoring are (1) electroencephalographic monitoring to evaluate brain activity for abnormal patterns or changes and to identify seizures, (2) neuroimaging to reveal structural changes and evidence of physical injury in and around the brain, and (3) near-infrared spectroscopy to monitor brain tissue oxygenation and detect changes in perfusion. This review will detail the aforementioned techniques and their use in the care of pediatric patients with congenital heart disease.

Differences in Quality of Life in Children Across the Spectrum of Congenital Heart Disease

OBJECTIVE

To create complexity groups based upon a patient's cardiac medical history and to test for group differences in health-related quality of life (HRQOL).

METHODS

Patients 8-18 years with congenital heart disease (CHD) and parent-proxies from the Pediatric Cardiac Quality of Life Inventory (PCQLI) Testing Study were included. Outcome variables included PCQLI Total, Disease Impact, and Psychosocial Impact scores. Using a patient's medical history (cardiac, neurologic, psychological, and cognitive diagnosis), latent class analysis (LCA) was used to create CHD complexity groups. Covariates included demographics and burden of illness (number of: school weeks missed, physician visits in the past year, and daily medications). Generalized estimation equations tested for differences in burden of illness and patient and parent-proxy PCQLI scores.

RESULTS

Using 1482 CHD patients (60% male; 84% white; age 12.3 ± 3.0 years), latent class analysis (LCA) estimates showed 4 distinct CHD complexity groups (Mild, Moderate 1, Moderate 2, and Severe). Increasing CHD complexity was associated with increased risk of learning disorders, seizures, mental health problems, and history of stroke. Greater CHD complexity was associated with greater burden of illness (P < .01) and lower patient- and parent-reported PCQLI scores (P < .001).

CONCLUSIONS

LCA identified 4 congenital heart disease (CHD) complexity groupings. Increasing CHD complexity was associated with higher burden of illness and worse patient- and parent-reported HRQOL.

A dynamic Norwood mortality estimation: Characterizing individual, updated, predicted mortality trajectories after the Norwood operation

Objective

Post-Norwood mortality remains high and unpredictable. Current models for mortality do not incorporate interstage events. We sought to determine the association of time-related interstage events, along with (pre)operative characteristics, with death post-Norwood and subsequently predict individual mortality.

Methods

From the Congenital Heart Surgeons' Society Critical Left Heart Obstruction cohort, 360 neonates underwent Norwood operations from 2005 to 2016. Risk of death post-Norwood was modeled using a novel application of parametric hazard analysis, in which baseline and operative characteristics and time-related adverse events, procedures, and repeated weight and arterial oxygen saturation measurements were considered. Individual predicted mortality trajectories that dynamically update (increase or decrease) over time were derived and plotted.

Results

After the Norwood, 282 patients (78%) progressed to stage 2 palliation, 60 patients (17%) died, 5 patients (1%) underwent heart transplantation, and 13 patients (4%) were alive without transitioning to another end point. In total, 3052 postoperative events occurred and 963 measures of weight and oxygen saturation were obtained. Risk factors for death included resuscitated cardiac arrest, moderate or greater atrioventricular valve regurgitation, intracranial hemorrhage/stroke, sepsis, lower longitudinal oxygen saturation, readmission, smaller baseline aortic diameter, smaller baseline mitral valve z-score, and lower longitudinal weight. Each patient's predicted mortality trajectory varied as risk factors occurred over time. Groups with qualitatively similar mortality trajectories were noted.

Conclusions

Risk of death post-Norwood is dynamic and most frequently associated with time-related postoperative events and measures, rather than baseline characteristics. Dynamic predicted mortality trajectories for individuals and their visualization represent a paradigm shift from population-derived insights to precision medicine at the patient level.

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.

Evaluation of Seizure Risk in Infants After Cardiopulmonary Bypass in the Absence of Deep Hypothermic Cardiac Arrest

Background

Guidelines recommend evaluation for electrographic seizures in neonates and children at risk, including after cardiopulmonary bypass (CPB). Although initial research using screening electroencephalograms (EEGs) in infants after CPB found a 21% seizure incidence, more recent work reports seizure incidences ranging 3–12%. Deep hypothermic cardiac arrest was associated with increased seizure risk in prior reports but is uncommon at our institution and less widely used in contemporary practice. This study seeks to establish the incidence of seizures among infants following CPB in the absence of deep hypothermic cardiac arrest and to identify additional risk factors for seizures via a prediction model.

Methods

A retrospective chart review was completed of all consecutive infants ≤ 3 months who received screening EEG following CPB at a single center within a 2-year period during 2017–2019. Clinical and laboratory data were collected from the perioperative period. A prediction model for seizure risk was fit using a random forest algorithm, and receiver operator characteristics were assessed to classify predictions. Fisher’s exact test and the logrank test were used to evaluate associations between clinical outcomes and EEG seizures.

Results

A total of 112 infants were included. Seizure incidence was 10.7%. Median time to first seizure was 28.1 h (interquartile range 18.9–32.2 h). The most important factors in predicting seizure risk from the random forest analysis included postoperative neuromuscular blockade, prematurity, delayed sternal closure, bypass time, and critical illness preoperatively. When variables captured during the EEG recording were included, abnormal postoperative neuroimaging and peak lactate were also highly predictive. Overall model accuracy was 90.2%; accounting for class imbalance, the model had excellent sensitivity and specificity (1.00 and 0.89, respectively).

Conclusions

Seizure incidence was similar to recent estimates even in the absence of deep hypothermic cardiac arrest. By employing random forest analysis, we were able to identify novel risk factors for postoperative seizure in this population and generate a robust model of seizure risk. Further work to validate our model in an external population is needed.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12028-021-01313-1.

Seizures Are Associated With Brain Injury in Infants Undergoing Extracorporeal Membrane Oxygenation

OBJECTIVE

Determine seizure frequency and association with neurologic outcomes in infants undergoing extracorporeal membrane oxygenation. Identify patient or clinical factors associated with seizures or brain injury on imaging.

METHODS

Retrospective, single-center study including infants less than 1 year of age, who underwent extracorporeal membrane oxygenation between 2012 and 2017.

RESULTS

A total of 104 infants met study criteria including 45 patients with continuous electroencephalographic (EEG) monitoring during their extracorporeal membrane oxygenation run and 59 infants without EEG. Seizures (electrographic-only or electro-clinical) were identified in 18 of the 45 (40%). Among the 18 infants with seizures, 14 (78%) had moderate to severe brain injury, whereas only 44% of those without seizures (12 of 27) on EEG had moderate to severe brain injury (P = .03). Cardiopulmonary resuscitation prior to extracorporeal membrane oxygenation (ECPR), mode of extracorporeal membrane oxygenation, length of stay, survival to discharge, and congenital heart disease were not associated with seizures. One of 10 patients with cyanotic congenital heart disease due to hypoplastic left heart syndrome had seizures compared with 7 of 10 patients with non-hypoplastic left heart syndrome lesions (P = .02). Seizures were associated with moderate to severe brain injury, after adjusting for ECPR and congenital heart disease (P = .04).

CONCLUSIONS

Electrographic seizures were common in patients undergoing extracorporeal membrane oxygenation and higher than previously reported. Seizures were associated with moderate to severe abnormalities on imaging, after adjusting for ECPR and congenital heart disease. This study adds to recent literature describing the risk of seizures in patients on extracorporeal membrane oxygenation and highlights the presence of brain injuries that may be identified by routine EEG surveillance.

Development and Validation of a Seizure Prediction Model in Neonates After Cardiac Surgery

BACKGROUND

Electroencephalographic seizures (ESs) after neonatal cardiac surgery are often subclinical and have been associated with poor outcomes. An accurate ES prediction model could allow targeted continuous electroencephalographic monitoring (CEEG) for high-risk neonates.

METHODS

ES prediction models were developed and validated in a multicenter prospective cohort where all postoperative neonates who underwent cardiopulmonary bypass (CPB) also underwent CEEG.

RESULTS

ESs occurred in 7.4% of neonates (78 of 1053). Model predictors included gestational age, head circumference, single-ventricle defect, deep hypothermic circulatory arrest duration, cardiac arrest, nitric oxide, extracorporeal membrane oxygenation, and delayed sternal closure. The model performed well in the derivation cohort (c-statistic, 0.77; Hosmer-Lemeshow, P = .56), with a net benefit (NB) over monitoring all and none over a threshold probability of 2% in decision curve analysis (DCA). The model had good calibration in the validation cohort (Hosmer-Lemeshow, P = .60); however, discrimination was poor (c-statistic, 0.61), and in DCA there was no NB of the prediction model between the threshold probabilities of 8% and 18%. By using a cut point that emphasized negative predictive value in the derivation cohort, 32% (236 of 737) of neonates would not undergo CEEG, including 3.5% (2 of 58) of neonates with ESs (negative predictive value, 99%; sensitivity, 97%).

CONCLUSIONS

In this large prospective cohort, a prediction model of ESs in neonates after CPB had good performance in the derivation cohort, with an NB in DCA. However, performance in the validation cohort was weak, with poor discrimination, poor calibration, and no NB in DCA. These findings support CEEG of all neonates after CPB.

Effect of perioperative amplitude-integrated electroencephalography on neurodevelopmental outcomes following infant heart surgery

The purpose of the current study was to determine the effect of perioperative amplitude-integrated electroencephalography (aEEG) on neurodevelopmental outcomes in infants with congenital heart disease (CHD). A total of 93 children with CHD were included in the current study. All patients enrolled in the present study had undergone cardiac surgery prior to 3 months of age and pre- or postoperative aEEG was monitored. Participants were assessed after 1 year using the Bayley Scales of Infant Test. A total of 82.2% of infants exhibited continuous normal voltage preoperatively (CNV) and 93.7% exhibited CNV postoperatively. Seizures were indicated in 2 infants preoperatively and 3 infants postoperatively. Compared with infants with PDI, infants with cyanotic CHD (β=17.218) exhibited a significantly lower MDI, an increased length of intensive care stay, and lower PDI scores (β=-0.577). Infants that underwent surgery with CPB exhibited higher PDI scores (β=11.956). Infants that exhibited behavioral problems also had lower PDI scores (β=-10.605). An abnormal preoperative background pattern and an absent postoperative SWC independently predicted poorer motor (P=0.014) and cognitive (P=0.049) outcomes at 1 year. The current study demonstrated that infants with CHD who underwent cardiac surgery prior to 3 months of age exhibited delayed neurodevelopmental outcomes, and that an aEEG assessment can aid in predicting these outcomes following surgery.

Electrographic seizure burden and outcomes following pediatric status epilepticus

Pediatric status epilepticus carries a substantial risk for morbidity and mortality, but the relationship between seizure burden, treatment, and outcome remains incompletely understood. This review summarizes the evidence linking seizure burden and outcomes among critically ill children in the intensive care unit (ICU), a population in whom accurate quantification of seizure burden is possible using continuous electroencephalographic monitoring. Several high-quality observational studies among critically ill children have reported an association between higher seizure burden and worse outcome, even after adjusting for potential confounders such as age, etiology, and illness severity. Although these studies support the hypothesis that seizures contribute to brain injury and worsen outcome, a causal link between seizures and outcome remains to be proven. The relationship between seizures and outcome is likely complex, and dependent on factors such as etiology, preexisting neurological disability, medication exposure, and possibly individual genetic factors. Studies attempting to define this complex relationship will need to measure and account for these factors in their analyses. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures".

Neurodevelopmental outcomes of children with congenital heart disease: A review

Congenital heart defects are the most common birth anomaly affecting approximately 1% of births. With improved survival in this population, there is enhanced ability to assess long-term morbidities including neurodevelopment. There is a wide range of congenital heart defects, from those with minimal physiologic consequence that do not require medical or surgical intervention, to complex structural anomalies requiring highly specialized medical management and intricate surgical repair or palliation. The impact of congenital heart disease on neurodevelopment is multifactorial. Susceptibility for adverse neurodevelopment increases with advancing severity of the defect with initial risk factors originating during gestation. Complex structural heart anomalies may pre-dispose the fetus to abnormal circulatory patterns in utero that ultimately impact delivery of oxygen rich blood to the fetal brain. Thus, the brain of a neonate born with complex congenital heart disease may be particularly vulnerable from the outset. That vulnerability is compounded during the newborn period and through childhood, as this population endures a myriad of medical and surgical interventions. For each individual patient, these factors are likely cumulative and synergistic with progression from fetal life through childhood. This review discusses the spectrum of risk factors that may impact neurodevelopment in children with congenital heart disease, describes current recommendations and practices for neurodevelopmental follow-up of children with congenital heart disease and reviews important neurodevelopmental trends in this high risk population.

Associations Between Age at Arterial Switch Operation, Brain Growth, and Development in Infants With Transposition of the Great Arteries

BACKGROUND

Brain injury, impaired brain growth, and long-term neurodevelopmental problems are common in children with transposition of the great arteries. We sought to identify clinical risk factors for brain injury and poor brain growth in infants with transposition of the great arteries undergoing the arterial switch operation, and to examine their relationship with neurodevelopmental outcome.

METHODS

The brains of 45 infants with transposition of the great arteries undergoing surgical repair were imaged pre- and postoperatively using magnetic resonance imaging. Brain weight z scores were calculated based on brain volume and autopsy reference data. Brain injury scores were determined as previously described. Neurodevelopment was assessed at 18 months using the Bayley-III scores of infant development. The relationships between clinical variables, brain injury, perioperative brain growth, and 18-month Bayley-III scores were analyzed.

RESULTS

On preoperative imaging, moderate or severe white matter injury was present in 10 of 45 patients, whereas stroke was seen in 4 of 45. A similar prevalence of injury was seen on postoperative imaging, and we were unable to identify any clinical risk factors for brain injury. Brain weight z scores decreased perioperatively in 35 of 45 patients. The presence of a ventricular septal defect ( P=0.009) and older age at surgery ( P=0.007) were associated with impaired perioperative brain growth. When patients were divided into those undergoing surgery during the first 2 weeks of life (32/45) versus those being repaired later (13/45), infants repaired later had significantly worse perioperative brain growth (late repair postoperative brain weight z = -1.0±0.90 versus early repair z = -0.33±0.64; P=0.008). Bayley-III testing scores fell within the normal range for all patients, although age at repair ( P=0.03) and days of open chest ( P=0.03) were associated with a lower composite language score, and length of stay was associated with a lower composite cognitive score ( P=0.02).

CONCLUSIONS

Surgery beyond 2 weeks of age is associated with impaired brain growth and slower language development in infants with transposition of the great arteries cared for at our center. Although the mechanisms underlying this association are still unclear, extended periods of cyanosis and pulmonary overcirculation may adversely impact brain growth and subsequent neurodevelopment.

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.

Amplitude-Integrated Electroencephalography for Early Recognition of Brain Injury in Neonates with Critical Congenital Heart Disease

OBJECTIVE

To study perioperative amplitude-integrated electroencephalography (aEEG) as an early marker for new brain injury in neonates requiring cardiac surgery for critical congenital heart disease (CHD).

STUDY DESIGN

This retrospective observational cohort study investigated 76 neonates with critical CHD who underwent neonatal surgery. Perioperative aEEG recordings were evaluated for background pattern (BGP), sleep-wake cycling (SWC), and ictal discharges. Spontaneous activity transient (SAT) rate, inter-SAT interval (ISI), and percentage of time with an amplitude <5 µV were calculated. Routinely obtained preoperative and postoperative magnetic resonance imaging of the brain were reviewed for brain injury (moderate-severe white matter injury, stroke, intraparenchymal hemorrhage, or cerebral sinovenous thrombosis).

RESULTS

Preoperatively, none of the neonates showed an abnormal BGP (burst suppression or worse) or ictal discharges. Postoperatively, abnormal BGP was seen in 18 neonates (24%; 95% CI, 14%-33%) and ictal discharges was seen in 13 neonates (17%; 95% CI, 8%-26%). Abnormal BGP and ictal discharges were more frequent in neonates with new postoperative brain injury (P = .08 and .01, respectively). Abnormal brain activity (ie, abnormal BGP or ictal discharges) was the single risk factor associated with new postoperative brain injury in multivariable logistic regression analysis (OR, 4.0; 95% CI, 1.3-12.3; P = .02). Postoperative SAT rate, ISI, or time <5 µV were not associated with new brain injury.

CONCLUSION

Abnormal brain activity is an early, bedside marker of new brain injury in neonates undergoing cardiac surgery. Not only ictal discharges, but also abnormal BGP, should be considered a clear sign of underlying brain pathology.

Outcomes following electrographic seizures and electrographic status epilepticus in the pediatric and neonatal ICUs

PURPOSE OF REVIEW

Increasing recognition of electrographic seizures and electrographic status epilepticus in critically ill neonates and children has highlighted the importance of identifying their potential contributions to neurological outcomes to guide optimal management.

RECENT FINDINGS

Recent studies in children and neonates have found an independent association between increasing seizure burden and worse short-term and long-term outcomes, even after adjusting for other important contributors to outcome such as seizure cause and illness severity. The risk of worse neurological outcome has been shown to increase above a seizure burden threshold of 12-13 min/h, which is considerably lower than the conventional definition of status epilepticus of 30 min/h. Randomized controlled trials in neonates have demonstrated that electroencephalography-targeted therapy can successfully reduce seizure burden, but due to their small size these trials have not been able to demonstrate that more aggressive electroencephalography-targeted treatment of both subclinical and clinical seizures results in improved outcome.

SUMMARY

Despite mounting evidence for an independent association between increasing seizure burden and worse outcome, further study is needed to determine whether early seizure identification and aggressive antiseizure treatment can improve neurodevelopmental outcomes.

Neurodevelopmental Abnormalities and Congenital Heart Disease: Insights Into Altered Brain Maturation

In the past 2 decades, it has become evident that individuals born with congenital heart disease (CHD) are at risk of developing life-long neurological deficits. Multifactorial risk factors contributing to neurodevelopmental abnormalities associated with CHD have been identified; however, the underlying causes remain largely unknown, and efforts to address this issue have only recently begun. There has been a dramatic shift in focus from newly acquired brain injuries associated with corrective and palliative heart surgery to antenatal and preoperative factors governing altered brain maturation in CHD. In this review, we describe key time windows of development during which the immature brain is vulnerable to injury. Special emphasis is placed on the dynamic nature of cellular events and how CHD may adversely impact the cellular units and networks necessary for proper cognitive and motor function. In addition, we describe current gaps in knowledge and offer perspectives about what can be done to improve our understanding of neurological deficits in CHD. Ultimately, a multidisciplinary approach will be essential to prevent or improve adverse neurodevelopmental outcomes in individuals surviving CHD.

Postoperative Amplitude-Integrated Electroencephalography Predicts Four-Year Neurodevelopmental Outcome in Children with Complex Congenital Heart Disease

OBJECTIVES

To evaluate the predictive value of pre- and postoperative amplitude-integrated electroencephalography (aEEG) on neurodevelopmental outcomes in children operated for congenital heart disease (CHD).

STUDY DESIGN

Prospectively enrolled cohort of 60 infants with CHD who underwent cardiac surgery with cardiopulmonary bypass in the first 3 months of life. Infants with a genetic comorbidity were excluded. aEEG was assessed for 12 hours pre- and 48 hours postoperatively. Background pattern was classified by the use of standard categories, and the presence of seizures and sleep-wake cycles (SWCs) was noted. Outcome at 1 and 4 years of age was assessed with standardized developmental tests.

RESULTS

Preoperatively, infants either showed continuous normal voltage (n = 56) or discontinuous normal voltage (n = 4). Postoperatively, abnormal background pattern (flat trace, burst suppression, or continuous low voltage) was detected in 7 (12%), discontinuous normal voltage in 37 (61%), and continuous normal voltage in 16 (27%) infants. Nineteen infants (32%) did not return to normal SWCs within the recording period. Seizures were detected in 4 infants preoperatively and in another 4 postoperatively. After we controlled for surgical and postoperative risk factors, abnormal postoperative background pattern and lack of return to SWCs independently predicted poorer intelligence quotient at 4 years (P = .03 and P = .04 respectively) but was not related to motor outcome.

CONCLUSION

aEEG is a useful bedside tool that helps to predict outcome in infants undergoing open-heart surgery for CHD. Abnormal postoperative background pattern and lack of return to SWCs are markers for subsequent impaired cognitive development.

Outcomes in Postoperative Pediatric Cardiac Surgical Patients Who Received an Antiepileptic Drug

BACKGROUND: Advances in cardiac operations over the last few decades, including corrective operations in early life, have dramatically increased the survival of children with congenital heart disease. However, postoperative care has been associated with neurologic complications, with seizures being the most common manifestation. The primary objective of this study is to describe the outcomes in pediatric patients who received an antiepileptic drug (AED) post-cardiac surgery. METHOD: A retrospective cohort study was performed in all patients less than 18 years of age who received an AED in the cardiovascular intensive care unit at Texas Children's Hospital from June 2002 until June 2012. Cardiac surgical patients initiated on phenobarbital, phenytoin, and levetiracetam were queried. Patients were excluded if the AED was not initiated on the admission for surgery. Patients who received 1 AED were compared to patients who received 2 AED, and differences in outcomes examined between the 3 AEDs used were evaluated. RESULTS: A total of 37 patients met the study criteria. Patients were initiated on an AED a median of 4 days following surgery and became seizure free a median of 1 day after initiation, with 65% remaining seizure free after the first dose. Half of all patients required 2 AEDs for seizure control, with a higher proportion of adolescents requiring 2 AEDs (p = 0.04). No differences were found when comparing the collected outcomes between phenobarbital, fosphenytoin, or levetiracetam. CONCLUSION: No adverse events were reported with the AEDs reviewed. Further work is necessary to evaluate long-term neurodevelopmental outcomes in this population and whether outcomes are a result of the AED or of other clinical sequelae.

Measuring the Severity of Neonatal Seizures: Temporal-Spatial Burden

PURPOSE

The American Clinical Neurophysiology Society recommends measuring neonatal seizures' severity by their frequency (number of seizures-anywhere per hour), burden (percentage of time with seizures-anywhere), or on a region-by-region, temporal-spatial basis. This study compares two reduced-channel montages for temporal-spatial seizure burden analyses and examines the agreement of seizures' quantification among these three methodologies.

METHODS

A convenience sample of 10 neonatal electroencephalograms was annotated for the beginnings and ends of seizures, which appeared anywhere in the full neonatal montage, then repeated on a more precise, region-by-region basis using 2 reduced-channel montages A and B. Seizure severity was measured by seizures-anywhere frequency, seizures-anywhere burden, and temporal-spatial seizure burdens using montages A and B. The results were compared by measuring their correlation and by linear regression modeling.

RESULTS

Seizures-anywhere frequency was correlated with seizures-anywhere burden (ρ = 0.77). However, a narrow range of seizures-anywhere frequencies corresponded with a broad range of seizures-anywhere burdens. Although there was high correlation between seizures-anywhere burdens and temporal-spatial seizure burdens (ρ = 0.92 montage A, ρ = 0.90 montage B), seizures-anywhere burdens were insensitive to variations in the spatial aspects of seizures, which were highly prevalent even in this small sample set. After adjusting for intrareader variability, the temporal-spatial seizure burdens measured by montages A and B were not significantly different (P = 0.56).

CONCLUSIONS

The severity of neonatal seizures is poorly represented by simple measures such as seizures-anywhere frequencies or burdens. The use of temporal-spatial seizure burden measurements is supported in work where great precision in quantifying neonatal seizures is required.

Neurodevelopmental Outcomes of the Child with Congenital Heart Disease

Survival after bypass surgery in moderate and severe congenital heart disease (CHD) has increased dramatically. Although cardiac outcome is often very good, these children are at increased risk of developmental impairments in all developmental domains. Risk factors for developmental impairment include a genetic disorder, preterm birth, longer intensive care stay, poorer socioeconomic environment, and more complex forms of CHD. Health care providers, patients, and parents must be aware and informed about noncardiac sequelae and tertiary centers performing open-heart surgery in neonates and infants must establish a neurodevelopmental follow-up program to provide regular neurodevelopmental assessments. These allow for individual counseling and early detection and treatment of developmental problems.

Subclinical seizures identified by postoperative electroencephalographic monitoring are common after neonatal cardiac surgery

OBJECTIVES

The American Clinical Neurophysiology Society recommends continuous electroencephalographic monitoring after neonatal cardiac surgery because seizures are common, often subclinical, and associated with worse neurocognitive outcomes. We performed a quality improvement project to monitor for postoperative seizures in neonates with congenital heart disease after surgery with cardiopulmonary bypass.

METHODS

We implemented routine continuous electroencephalographic monitoring and reviewed the results for an 18-month period. Clinical data were collected by chart review, and continuous electroencephalographic tracings were interpreted using standardized American Clinical Neurophysiology Society terminology. Electrographic seizures were classified as electroencephalogram-only or electroclinical seizures. Multiple logistic regression was used to assess associations between seizures and potential clinical and electroencephalogram predictors.

RESULTS

A total of 161 of 172 eligible neonates (94%) underwent continuous electroencephalographic monitoring. Electrographic seizures occurred in 13 neonates (8%) beginning at a median of 20 hours after return to the intensive care unit after surgery. Neonates with all types of congenital heart disease had seizures. Seizures were electroencephalogram only in 11 neonates (85%). Status epilepticus occurred in 8 neonates (62%). In separate multivariate models, delayed sternal closure or longer deep hypothermic circulatory arrest duration was associated with an increased risk for seizures. Mortality was higher among neonates with than without seizures (38% vs 3%, P < .001).

CONCLUSIONS

Continuous electroencephalographic monitoring identified seizures in 8% of neonates after cardiac surgery with cardiopulmonary bypass. The majority of seizures had no clinical correlate and would not have been otherwise identified. Seizure occurrence is a marker of greater illness severity and increased mortality. Further study is needed to determine whether seizure identification and management lead to improved outcomes.

All this monitoring…what's necessary, what's not?

The goal of perioperative monitoring is to aid the clinician in optimizing care to achieve the best possible survival with the lowest possible morbidity. Ideally, we would like to have monitoring that can rapidly and accurately identify perturbations in circulatory well-being that would permit timely intervention and allow for restoration before the patient is damaged. The evidence to support the use of our standard monitoring strategies (continuous electrocardiography, blood pressure, central venous pressure, oxygen saturation and capnography) is based on expert opinion, case series, or at best observational studies. While these monitoring parameters will identify life-threatening events, they provide no direct information concerning the oxygen economy of the patient. Nevertheless, they are mandated by professional societies representing specialists in cardiac disease, critical care, and anesthesiology. Additional non-routine monitoring strategies that provide data concerning the body's oxygen economy, such as venous saturation monitoring and near infrared spectroscopy, have shown promise in prospective observational studies in managing these complex groups of patients. Ideally, high-level evidence would be required before adopting these newer strategies, but in the absence of new funding sources and the challenges of the wide variation in practice patterns between centers, this seems unlikely. The evidence supporting the current standard perioperative monitoring strategies will be reviewed. In addition, evidence supporting non-routine monitoring strategies will be reviewed and their potential for added benefit assessed.

Identified mortality risk factors associated with presentation, initial hospitalisation, and interstage period for the Norwood operation in a multi-centre registry: a report from the national pediatric cardiology-quality improvement collaborative

INTRODUCTION

Despite improvements in care following Stage 1 palliation, interstage mortality remains substantial. The National Pediatric Cardiology-Quality Improvement Collaborative captures clinical process and outcome data on infants discharged into the interstage period after Stage 1. We sought to identify risk factors for interstage mortality using these data.

MATERIALS AND METHODS

Patients who reached Stage 2 palliation or died in the interstage were included. The analysis was considered exploratory and hypothesis generating. Kaplan-Meier survival analysis was used to screen for univariate predictors, and Cox multiple regression modelling was used to identify potential independent risk factors.

RESULTS

Data on 247 patients who met the criteria between June, 2008 and June, 2011 were collected from 33 surgical centres. There were 23 interstage mortalities (9%). The identified independent risk factors of interstage mortality with associated relative risk were: hypoplastic left heart syndrome with aortic stenosis and mitral atresia (relative risk = 13), anti-seizure medications at discharge (relative risk = 12.5), earlier gestational age (relative risk = 11.1), nasogastric or nasojejunal feeding (relative risk = 5.5), unscheduled readmissions (relative risk = 5.3), hypoplastic left heart syndrome with aortic atresia and mitral stenosis (relative risk = 5.2), fewer clinic visits with primary cardiologist identified (relative risk = 3.1), and fewer post-operative vasoactive medications (relative risk = 2.2).

CONCLUSION

Interstage mortality remains substantial, and there are multiple potential risk factors. Future efforts should focus on further exploration of each risk factor, with potential integration of the factors into surveillance schemes and clinical practice strategies.

Electrographic seizures and status epilepticus in critically ill children and neonates with encephalopathy

Electrographic seizures are seizures that are evident on EEG monitoring. They are common in critically ill children and neonates with acute encephalopathy. Most electrographic seizures have no associated clinical changes, and continuous EEG monitoring is necessary for identification. The effect of electrographic seizures on outcome is the focus of active investigation. Studies have shown that a high burden of electrographic seizures is associated with worsened clinical outcome after adjustment for cause and severity of brain injury, suggesting that a high burden of such seizures might independently contribute to secondary brain injury. Further research is needed to determine whether identification and management of electrographic seizures reduces secondary brain injury and improves outcome in critically ill children and neonates.

Impact of fetal development on neurocognitive performance of adolescents with cyanotic and acyanotic congenital heart disease

BACKGROUND

Our aims were to evaluate the neurocognitive performance in adolescents with congenital heart disease (CHD) and to determine whether parameters of fetal development evaluated in neonates, such as head circumference, length, weight, and Apgar scores, are somehow related to their neurocognitive performance.

METHODS

We evaluated 77 CHD patients (43 males) aged from 13 to 18 years old (mean = 15.04 ± 1.86), 46 cyanotic, 23 with tetralogy of Fallot (TF), 23 with transposition of the great arteries (TGA) and 31 acyanotic with ventricular septal defect (VSD) enrolled in this study. The control group included 16 healthy children (11 males) ages ranging from 13 to 18 years old (mean = 15.69 years ± 1.44 years). All assessment measures for CHD patients were once obtained in a tertiary hospital; the control group was evaluated in school. Neuropsychological assessment included Wechsler's Digit Test, direct and reverse (WDD and WDR) and Symbol Search, Rey's Complex Figure (RCF), BADS's Key Searching Test, Color-Word Stroop Test (CWS), Trail Making Test (TMT), and Logical Memory Task (LMT). We evaluated some fetal parameters, such as head circumference, weight and length assessed at birth, and neonatal parameters, such as Apgar scores at 1 and 5 minutes after birth. We also registered some surgical parameters, such as the age at first operation and the number of surgeries.

RESULTS

CHD patients compared with control group showed lower scores on every test, except for logical memory task. Patients with VSD when compared with patients with TF and TGA showed better results in all neuropsychological tests, although the only significant differences were in RCF, copy (F = 4936; P = .010). Several correlations were apparent between fetal/neonatal parameters and neuropsychological abilities in each type of CHD. However, head circumference at birth stands as the main correlation with cognitive development later on in all kinds of CHD (WDD: rho = .339, P = .011; RCF, copy: rho = 0.297, P = .027; CWS, interference: rho = 0.283, P = .036; TMT-A: rho = -0.321, P = .017). We analyzed the predicting relevance of several variables to cognitive performance of adolescents with CHD and confirmed that "cyanosis" stands as the main predictor (â = -4.758; t = -2.622; P = .011).

CONCLUSIONS

Adolescents with CHD have worse neuropsychological performance than the control group, mainly the cyanotic patients. Fetal circulation seems to have impact on cerebral and somatic growth, predicting cognitive impairment in adolescents with CHD.

A review of long-term EEG monitoring in critically ill children with hypoxic-ischemic encephalopathy, congenital heart disease, ECMO, and stroke

Continuous EEG monitoring is being used with increasing frequency in critically ill children with hypoxic ischemic encephalopathy, congenital heart disease, stroke, and extracorporeal membrane oxygenation (ECMO). The primary indication for EEG monitoring is to identify electrographic seizures and electrographic status epilepticus, which have been associated with worse outcome in some populations. A secondary indication is to provide prognostic information. This review summarizes the available data regarding continuous EEG monitoring in critically ill children with special attention to hypoxic ischemic encephalopathy, congenital heart disease, stroke, and children undergoing ECMO.

Postoperative electroencephalographic seizures are associated with deficits in executive function and social behaviors at 4 years of age following cardiac surgery in infancy

OBJECTIVE

The occurrence of an electroencephalographic (EEG) seizure after surgery for complex congenital heart defects has been associated with worse neurodevelopmental (ND) outcomes. We previously identified postoperative seizures documented by 48-hour EEG monitoring in 11% of 178 neonates and infants. Evaluation at 1 year of age did not identify an adverse effect of an EEG seizure on ND outcomes. The current study was undertaken to determine if testing in the preschool period would identify deficits that become apparent as children develop.

METHODS

The ND outcomes assessed at 4 years of age included cognition, language, attention, impulsivity, executive function, behavior problems, academic achievement, and visual and fine motor skills.

RESULTS

Developmental evaluations were performed in 132 (87%) of 151 survivors. For the entire cohort, the Full-Scale IQ was 95.0 ± 18.5. IQ was 95.1 ± 18.7 for patients without a history of seizure and 93.6 ± 16.7 for those with a history of seizure. After covariate adjustment, occurrence of an EEG seizure was associated with worse executive function (P = .037) and impaired social interactions/restricted behavior (P = .05). Seizures were not significantly associated with worse performance for cognition, language, attention, impulsivity, academic achievement, or motor skills (all P > .1).

CONCLUSIONS

The occurrence of a postoperative seizure is a biomarker of brain injury. This study confirms that postoperative EEG seizures are associated with worse ND outcomes, characterized by impairments of executive function and a higher prevalence of deficits in social interactions and repetitive/restricted behaviors in preschool survivors of cardiac surgery in infancy. However, EEG seizures were not associated with worse cognitive, language, or motor skills.

Electroencephalographic monitoring in the pediatric intensive care unit

Continuous electroencephalographic (CEEG) monitoring is used with increasing frequency in critically ill children to provide insight into brain function and to identify electrographic seizures. CEEG monitoring use often impacts clinical management, most often by identifying electrographic seizures and status epilepticus. Most electrographic seizures have no clinical correlate, and thus would not be identified without CEEG monitoring. There are increasing data showing that electrographic seizures and electrographic status epilepticus are associated with worse outcome. Seizure identification efficiency may be improved by further development of quantitative electroencephalography trends. This review describes the clinical impact of CEEG data, the epidemiology of electrographic seizures and status epilepticus, the impact of electrographic seizures on outcome, the utility of quantitative electroencephalographic trends for seizure identification, and practical considerations regarding CEEG monitoring.

Surgical considerations in the management of hypoplastic left heart syndrome

Hypoplastic left heart syndrome is a congenital heart defect characterized by hypoplasia of left heart structures. Over the past 3 decades, there have been advances in techniques and management in the care of these patients. We discuss shunt selection, operative strategies, transplantation, and outline various facets of management at the University of Florida. This is a review of the literature highlighting some of the technical aspects of the preoperative, operative, and postoperative care that are important in today's management of hypoplastic left heart syndrome.

Neonatal seizures and status epilepticus

Neonatal seizures are common, often require EEG monitoring for diagnosis and management, may be associated with worse neurodevelopmental outcome, and can often be treated with existing anticonvulsants. A neonatal electrographic seizure is defined as a sudden, repetitive, evolving, and stereotyped event of abnormal electrographic pattern with amplitude of at least 2 μV and a minimum duration of 10 seconds. The diagnosis of neonatal seizures relies heavily on the neurophysiologist's interpretation of EEG. Consideration of specific criteria for the definition of a neonatal seizure, including seizure duration, location, morphology, evolution, semiology, and overall seizure burden, has utility for both the clinician and the researcher. The importance of EEG in the diagnosis and management of neonatal seizures, the electrographic characteristics of neonatal seizures, the impact of neonatal seizures on outcome, and tools to aid in the identification of neonatal seizures are reviewed.

Gross motor development is delayed following early cardiac surgery

OBJECTIVE

To describe the gross motor development of infants who had undergone cardiac surgery in the neonatal or early infant period.

METHODS

Gross motor performance was assessed when infants were 4, 8, 12, and 16 months of age with the Alberta Infant Motor Scale. This scale is a discriminative gross motor outcome measure that may be used to assess infants from birth to independent walking. Infants were videotaped during the assessment and were later evaluated by a senior paediatric physiotherapist who was blinded to each infant's medical history, including previous clinical assessments. Demographic, diagnostic, surgical, critical care, and medical variables were considered with respect to gross motor outcomes.

RESULTS

A total of 50 infants who underwent elective or emergency cardiac surgery at less than or up to 8 weeks of age, between July 2006 and January 2008, were recruited to this study and were assessed at 4 months of age. Approximately, 92%, 84%, and 94% of study participants returned for assessment at 8, 12, and 16 months of age, respectively. Study participants had delayed gross motor development across all study time points; 62% of study participants did not have typical gross motor development during the first year of life. Hospital length of stay was associated with gross motor outcome across infancy.

CONCLUSION

Active gross motor surveillance of all infants undergoing early cardiac surgery is recommended. Further studies of larger congenital heart disease samples are required, as are longitudinal studies that determine the significance of these findings at school age and beyond.

Performance of 2-year-old children after early surgery for congenital heart disease on the Bayley Scales of Infant and Toddler Development, Third Edition

BACKGROUND

Previous research on developmental outcomes of infants with congenital heart disease (CHD) has shown delays in both cognitive and motor skills.

AIMS

To describe outcomes on the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III) for infants with CHD and to compare those findings to published results for similar samples of infants assessed on the 2nd edition of the Bayley Scales (BSID-II).

STUDY DESIGN

Prospective cohort.

PARTICIPANTS AND OUTCOME MEASURES

Of 50 infants with CHD who participated in this longitudinal study (2006-2008) at the Royal Children's Hospital in Melbourne, Australia, 47 were assessed on the Bayley-III (median age=24.5 months), administered by a psychologist or neonatologist. Although neither assessor was blind to the CHD diagnosis, they were unaware of results of previous developmental assessments conducted in this longitudinal study.

RESULTS

For the Bayley-III cognitive composite score, 17.0% of infants showed mild delays (1-2 SD below the mean), 2.1% had moderate delays (2-3 SD below the mean), and none had severe delays (greater than 3 SD below the mean). Motor composite scores showed mild delays in 10.9% of infants and moderate delays in 2.2%; none had severe motor delays. These findings differ from study results using the BSID-II in similar infants.

CONCLUSIONS

The Bayley-III may underestimate developmental delay in 2-year-old children with CHD when compared to results of similar children tested at 12-36 months of age on the BSID-II.

Neurodevelopmental outcomes in children with congenital heart disease: evaluation and management: a scientific statement from the American Heart Association

BACKGROUND

The goal of this statement was to review the available literature on surveillance, screening, evaluation, and management strategies and put forward a scientific statement that would comprehensively review the literature and create recommendations to optimize neurodevelopmental outcome in the pediatric congenital heart disease (CHD) population.

METHODS AND RESULTS

A writing group appointed by the American Heart Association and American Academy of Pediatrics reviewed the available literature addressing developmental disorder and disability and developmental delay in the CHD population, with specific attention given to surveillance, screening, evaluation, and management strategies. MEDLINE and Google Scholar database searches from 1966 to 2011 were performed for English-language articles cross-referencing CHD with pertinent search terms. The reference lists of identified articles were also searched. The American College of Cardiology/American Heart Association classification of recommendations and levels of evidence for practice guidelines were used. A management algorithm was devised that stratified children with CHD on the basis of established risk factors. For those deemed to be at high risk for developmental disorder or disabilities or for developmental delay, formal, periodic developmental and medical evaluations are recommended. A CHD algorithm for surveillance, screening, evaluation, reevaluation, and management of developmental disorder or disability has been constructed to serve as a supplement to the 2006 American Academy of Pediatrics statement on developmental surveillance and screening. The proposed algorithm is designed to be carried out within the context of the medical home. This scientific statement is meant for medical providers within the medical home who care for patients with CHD.

CONCLUSIONS

Children with CHD are at increased risk of developmental disorder or disabilities or developmental delay. Periodic developmental surveillance, screening, evaluation, and reevaluation throughout childhood may enhance identification of significant deficits, allowing for appropriate therapies and education to enhance later academic, behavioral, psychosocial, and adaptive functioning.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

Impact of congenital heart disease on fetal brain development and injury

PURPOSE OF REVIEW

Advances in cardiac surgical techniques and intensive care have led to improved survival in babies with congenital heart disease (CHD). Although it is true that the majority of children with CHD today survive, many have impaired neurodevelopmental outcome. Although continuing to improve short-term morbidity and mortality are important goals, recent research has focused on defining the impact of CHD on brain development and brain injury in utero.

RECENT FINDINGS

The impact of CHD on the developing brain of the fetus and infant will be discussed. Neurologic abnormalities detectable prior to surgery will be described and postnatal progression of abnormalities will be highlighted. Potential causes of these findings will be discussed, including altered cerebral blood flow in utero, and brain development and risk for in-utero and postnatal brain injury. Finally, neurologic and developmental outcome after surgical repair of CHD will be reviewed.

SUMMARY

Neurodevelopmental evaluation preoperatively and postoperatively in CHD patients should be standard practice, not only to identify those with impairments who would benefit from intervention services but also to identify risk factors and strategies to optimize outcome. Fetal management and intervention strategies for specific defects may ultimately play a role in improving in-utero hemodynamics and increasing cerebral oxygen delivery to enhance brain development.

Occurrence and predictors of developmental impairments in 3-year-old children with congenital heart defects

OBJECTIVE

To examine the occurrence of developmental impairments in 3-year-old children with varying severity of congenital heart defects (CHD) and to identify predictors associated with developmental impairment in children with severe CHD.

METHODS

Prospective data collected at birth, 6, 18, and 36 months from the Norwegian Mother and Child Cohort Study (MoBa), conducted by the Norwegian Institute of Public Health, were linked with a nationwide medical CHD registry, and 175 three year olds with CHD in a cohort of 44,044 children were identified. Children with mild/moderate (n = 115) and severe (n = 60) CHD were compared with children without CHD (43,929) on motor, communication, and social impairments as reported by mothers in Norwegian Mother and Child Cohort Study questionnaires. Predictors of developmental impairment were analyzed for the group with severe CHD.

RESULTS

Children with severe CHD had >3 times higher odds of communication and gross motor impairments compared with controls, and had 2 times higher odds of any developmental impairment compared with controls. Children with mild and moderate CHD had >2 times higher odds of gross motor impairment but did not otherwise differ from controls. Predictors of impairment identified were previous developmental impairments and smaller head circumference at birth.

CONCLUSION

Children with severe CHD have increased odds of developmental impairments at age 3 years. Early developmental impairments are associated with later developmental impairments, suggesting lasting impairments and not merely temporary delay. Patient-specific conditions at birth should be considered and motor and communication support provided to potentially improve outcomes in children with CHD.

The effect of cardioplegic solution-induced sodium concentration fluctuation on postoperative seizure in pediatric cardiac patients

BACKGROUND

Despite potential benefits of histidine-tryptophan-ketoglutarate (HTK) solution as a cardioplegic solution, it can cause hyponatremia, especially in pediatric patients. Fluctuations in the sodium concentration during cardiopulmonary bypass (CPB) can adversely affect the central nervous system. We evaluated the relationship between the cardioplegic solution, the fluctuation of sodium concentration, and the incidence of postoperative seizure in pediatric cardiac patients.

METHODS

The medical records of 628 patients were reviewed for the occurrence of a postoperative seizure, type of cardioplegic solution (HTK or del Nido solution), and intraoperative data. A change of sodium concentration exceeding 15 mmol/L (ΔNa>15) during CPB was defined as a significant fluctuation of sodium concentration.

RESULTS

Postoperative seizures were detected in 18 patients (2.9%). The ΔNa>15 was detected in 63 of 189 patients (33.3%) who received the HTK solution and in 14 of 439 patients (3.2%) who received the del Nido solution (p<0.001). The incidence of ΔNa>15 was strongly associated with postoperative seizure (odds ratio, 6.3; 95% confidence interval, 2.4 to 16.4, p=0.001). After adjusting for potential confounders, the ΔNa>15 remained significantly associated with postoperative seizure (odds ratio, 3.9; 95% confidence interval, 1.3 to 12.3, p=0.018).

CONCLUSIONS

Histidine-tryptophan-ketoglutarate solution during CPB frequently causes fluctuations of sodium concentration, usually combined with hyponatremia, which is associated with postoperative seizure. Special attention to sodium concentration is required, particularly when HTK solution is used in pediatric cardiac patients.

Brain maturity and brain injury in newborns with cyanotic congenital heart disease

Patients with congenital heart disease (CHD) are at high risk for adverse neurodevelopmental outcomes. The aim of this work was to assess brain maturity and brain injury in newborns with cyanotic CHD using proton magnetic resonance spectroscopy (MRS). The study included 38 newborns with cyanotic CHD (study group) and 20 healthy full-term newborns (control group) matched together regarding gestational age and sex. Three-dimensional MRS showed that the mean ratio of N-acetylaspartate to choline (Ch) was significantly lower in newborns with cyanotic CHD (0.55 ± 0.08) compared with controls (0.67 ± 0.11) (p < 0.001). However, the mean ratio of lactate to Ch metabolite was significantly higher in the studied cases (0.14 ± 0.04) compared with controls (0.09 ± 0.04) (p < 0.001). The mean value for average diffusivity was 1.41 ± 0.06 in newborns with cyanotic CHD compared with 1.27 ± 0.07 in control newborns (p < 0.001), and the mean value for white-matter fractional anisotropy was 0.19 ± 0.03 in cyanotic newborns and 0.25 ± 0.08 in controls (p < 0.001). Newborns with cyanotic CHD are at increased risk of cerebral white matter injury as well as poor brain maturity. MRS provides a surrogate marker for early detection of such brain abnormalities.

Impact of congenital heart disease on brain development and neurodevelopmental outcome

Advances in cardiac surgical techniques and perioperative intensive care have led to improved survival in babies with congenital heart disease (CHD). While it is true that the majority of children with CHD today will survive, many will have impaired neurodevelopmental outcome across a wide spectrum of domains. While continuing to improve short-term morbidity and mortality is an important goal, recent and ongoing research has focused on defining the impact of CHD on brain development, minimizing postnatal brain injury, and improving long-term outcomes. This paper will review the impact that CHD has on the developing brain of the fetus and infant. Neurologic abnormalities detectable prior to surgery will be described. Potential etiologies of these findings will be discussed, including altered fetal intrauterine growth, cerebral blood flow and brain development, associated congenital brain abnormalities, and risk for postnatal brain injury. Finally, reported neurodevelopmental outcomes after surgical repair of CHD will be reviewed.

A systematic review of motor and cognitive outcomes after early surgery for congenital heart disease

CONTEXT

Brain injury is the most common long-term complication of congenital heart disease requiring surgery during infancy. It is clear that the youngest patients undergoing cardiac surgery, primarily neonates and young infants, are at the greatest risk for brain injury. Developmental anomalies sustained early in life have lifelong repercussions.

OBJECTIVE

We conducted a systematic review to examine longitudinal studies of cognitive and/or motor outcome after cardiac surgery during early infancy.

METHODS

Electronic searches were performed in Medline, the Cumulative Index to Nursing and Allied Health Literature (Cinahl), and Embase (1998-2008). The search strategy yielded 327 articles, of which 65 were reviewed. Eight cohorts provided prospective data regarding the cognitive and/or motor outcome of infants who had undergone surgery for congenital heart disease before 6 months of age. Two authors, Ms Snookes and Dr Gunn, independently extracted data and presented results according to 3 subgroups for age of follow-up: early development (1 to <3 years); preschool age (3-5 years); and school age (>5 to 17 years). Weighted analysis was undertaken to pool the results of studies when appropriate.

RESULTS

All of the identified studies reported results of the Bayley Scales of Infant Development for children younger than the age of 3. Outcome data as reported by the Bayley Scales were combined for infants assessed at 1 year of age, revealing a weighted mean Mental Development Index of 90.3 (95% confidence interval: 88.9-91.6) and Psychomotor Development Index of 78.1 (95% confidence interval: 76.4-79.7). Additional analysis was limited by a lack of data at preschool and school age.

CONCLUSIONS

With this review we identified a limited number of prospective studies that systematically addressed outcome in patients at the highest risk. These studies consistently revealed cognitive and motor delay in children after cardiac surgery during early infancy. Additional investigation is required to ascertain the consequences of such impairment during later childhood and into adult life.

Congenital heart disease and brain development

Brain and heart development occur simultaneously in the human fetus. Given the depth and complexity of these shared morphogenetic programs, it is perhaps not surprising that disruption of organogenesis in one organ will impact the development of the other. Newborns with congenital heart disease show a high frequency of acquired focal brain injury on sensitive magnetic resonance imaging studies in the perioperative period. The surprisingly high incidence of white matter injury in these term newborns suggests a unique vulnerability and may be related to a delay in brain development. These abnormalities in brain development identified with MRI in newborns with congenital heart disease might reflect abnormalities in cerebral blood flow while in utero. A complete understanding of the mechanisms of white matter injury in the term newborn with congenital heart disease will require further investigation of the timing, extent, and causes of delayed fetal brain development in the presence of congenital heart disease.