Reliability and accuracy of EEG interpretation for estimating age in preterm infants

OBJECTIVES

To determine the accuracy of, and agreement among, EEG and aEEG readers' estimation of maturity and a novel computational measure of functional brain age (FBA) in preterm infants.

METHODS

Seven experts estimated the postmenstrual ages (PMA) in a cohort of recordings from preterm infants using cloud-based review software. The FBA was calculated using a machine learning-based algorithm. Error analysis was used to determine the accuracy of PMA assessments and intraclass correlation (ICC) was used to assess agreement between experts.

RESULTS

EEG recordings from a PMA range 25 to 38 weeks were successfully interpreted. In 179 recordings from 62 infants interpreted by all human readers, there was moderate agreement between experts (aEEG ICC = 0.724; 95%CI:0.658-0.781 and EEG ICC = 0.517; 95%CI:0.311-0.664). In 149 recordings from 61 infants interpreted by all human readers and the FBA algorithm, random and systematic errors in visual interpretation of PMA were significantly higher than the computational FBA estimate. Tracking of maturation in individual infants showed stable FBA trajectories, but the trajectories of the experts' PMA estimate were more likely to be obscured by random errors. The accuracy of visual interpretation of PMA estimation was compromised by neurodevelopmental outcome for both aEEG and EEG review.

INTERPRETATION

Visual assessment of infant maturity is possible from the EEG or aEEG, with an average of human experts providing the highest accuracy. Tracking PMA of individual infants was hampered by errors in experts' estimates. FBA provided the most accurate maturity assessment and has potential as a biomarker of early outcome.

Hearing Loss after Cardiac Surgery in Infancy: An Unintended Consequence of Life-Saving Care

OBJECTIVES

To investigate the prevalence of hearing loss after cardiac surgery in infancy, patient and operative factors associated with hearing loss, and the relationship of hearing loss to neurodevelopmental outcomes.

STUDY DESIGN

Audiologic and neurodevelopmental evaluations were conducted on 348 children who underwent repair of congenital heart disease at the Children's Hospital of Philadelphia as part of a prospective study evaluating neurodevelopmental outcomes at 4 years of age. A prevalence estimate was calculated based on presence and type of hearing loss. Potential risk factors and the impact of hearing loss on neurodevelopmental outcomes were evaluated.

RESULTS

The prevalence of hearing loss was 21.6% (95% CI, 17.2-25.9). The prevalence of conductive hearing loss, sensorineural hearing loss, and indeterminate hearing loss were 12.4% (95% CI, 8.8-16.0), 6.9% (95% CI, 4.1-9.7), and 2.3% (95% CI, 0.6-4.0), respectively. Only 18 of 348 subjects (5.2%) had screened positive for hearing loss before this study and 10 used a hearing aid. After adjusting for patient and operative covariates, younger gestational age, longer postoperative duration of stay, and a confirmed genetic anomaly were associated with hearing loss (all P < .01). The presence of hearing loss was associated with worse language, cognition and attention (P <.01).

CONCLUSIONS

These findings suggest that the prevalence of hearing loss in preschool children after heart surgery in infancy may be 20-fold higher than in the 1% prevalence seen in the general population. Younger gestational age, presence of a genetic anomaly, and longer postoperative duration of stay were associated with hearing loss. Hearing loss was associated with worse neurodevelopmental outcomes.

Rates of autism and potential risk factors in children with congenital heart defects

OBJECTIVE

Atypical development, behavioral difficulties, and academic underachievement are common morbidities in children with a history of congenital heart defects and impact quality of life. Language and social-cognitive deficits have been described, which are associated with autism spectrum disorders. The current study aimed to assess the rates of autism spectrum disorders in a large sample of children with a history of congenital heart defects and to assess medical, behavioral, and individual factors that may be associated with the risk of autism spectrum disorders.

DESIGN

Participants included 195 children with a history of congenital heart defects, who are followed in a large-scale longitudinal study. Measures included behavioral data from 4-year-old neurodevelopmental evaluations and parent-report data from a later annual follow-up.

RESULTS

Using established cutoffs on an autism spectrum disorder screener, children with congenital heart defects showed higher rates of "possible" autism spectrum disorders than national rates, (Chi-square Test of Equal Proportions), all Ps < .05. A stepwise variable selection method was used to create a "best prediction model" and multivariable logistic regression was used to identify variables predicting diagnostic status. Factors associated with diagnostic risk included medical (delayed sternal closure, prematurity, positive genetic findings), behavioral (cognitive, language, attention issues), and individual (socioeconomic, cultural/racial) variables. ROC analyses identified a cutoff of 7 to maximize sensitivity/specificity based on parent-reported diagnosis.

CONCLUSIONS

Risk of autism spectrum disorder screening status in children with congenital heart defects was higher than expected from population rates. Findings highlight the need for referral to a specialist to assess the presence and severity of social-communication issues and congenital heart defects population-specific screening thresholds for children with concern for autism spectrum disorders.

Increasing cumulative exposure to volatile anesthetic agents is associated with poorer neurodevelopmental outcomes in children with hypoplastic left heart syndrome

OBJECTIVES

Despite improved survival in children with hypoplastic left heart syndrome (HLHS), significant concern persists regarding their neurodevelopmental (ND) outcomes. Previous studies have identified patient factors, such as prematurity and genetic syndromes, to be associated with worse ND outcomes. However, no consistent relationships have been identified among modifiable management factors, including cardiopulmonary bypass strategies, and ND outcomes after cardiac surgery in infancy. Studies in immature animals, including primates, have demonstrated neurodegeneration and apoptosis in the brain after certain levels and extended durations of anesthetic exposure. Retrospective human studies have also suggested relationships between adverse ND effects and anesthetic exposure.

METHODS

Cumulative minimum alveolar concentration hours (MAC-hrs) of exposure to volatile anesthetic agents (VAA) (desflurane, halothane, isoflurane, and sevoflurane) were collected from an anesthetic database and medical record review for 96 patients with HLHS or variants. ND testing was performed between ages 4 and 5 years, including full-scale IQ, verbal IQ, performance IQ, and processing speed. Four generalized linear modes were hypothesized a priori and tested using a Gaussian (normal) distribution with an identity link.

RESULTS

Cumulative VAA exposure ranged from 0 to 35.3 MAC-hrs (median 7.5 hours). Using specified covariates identified previously as significant predictors of ND outcomes, statistically significant relationships were identified between total MAC-hrs exposure and worse full-scale IQ and verbal IQ scores (P's < .05) alone and after adjusting for relevant covariates.

CONCLUSIONS

Increased cumulative MAC-hrs exposure to VAA is associated with worse ND outcomes in certain domains in children with HLHS and variants.

Clinical and histopathological outcomes in patients with SCN1A mutations undergoing surgery for epilepsy

OBJECT

Mutations in the sodium channel alpha 1 subunit gene (SCN1A) have been associated with a wide range of epilepsy phenotypes including Dravet syndrome. There currently exist few histopathological and surgical outcome reports in patients with this disease. In this case series, the authors describe the clinical features, surgical pathology, and outcomes in 6 patients with SCN1A mutations and refractory epilepsy who underwent focal cortical resection prior to uncovering the genetic basis of their epilepsy.

METHODS

Medical records of SCN1A mutation-positive children with treatment-resistant epilepsy who had undergone resective epilepsy surgery were reviewed retrospectively. Surgical pathology specimens were reviewed.

RESULTS

All 6 patients identified carried diagnoses of intractable epilepsy with mixed seizure types. Age at surgery ranged from 18 months to 20 years. Seizures were refractory to surgery in every case. Surgical histopathology showed evidence of subtle cortical dysplasia in 4 of 6 patients, with more neurons in the molecular layer of the cortex and white matter.

CONCLUSIONS

Cortical resection is unlikely to be beneficial in these children due to the genetic defect and the unexpected neuropathological finding of mild diffuse malformations of cortical development. Together, these findings suggest a diffuse pathophysiological mechanism of the patients' epilepsy which will not respond to focal resective surgery.

Interobserver agreement for neonatal seizure detection using multichannel EEG

Objective

To determine the interobserver agreement (IOA) of neonatal seizure detection using the gold standard of conventional, multichannel EEG.

Methods

A cohort of full‐term neonates at risk of acute encephalopathy was included in this prospective study. The EEG recordings of these neonates were independently reviewed for seizures by three international experts. The IOA was estimated using statistical measures including Fleiss' kappa and percentage agreement assessed over seizure events (event basis) and seizure duration (temporal basis).

Results

A total of 4066 h of EEG recordings from 70 neonates were reviewed with an average of 2555 seizures detected. The IOA was high with temporal assessment resulting in a kappa of 0.827 (95% CI: 0.769–0.865; n = 70). The median agreement was 83.0% (interquartile range [IQR]: 76.6–89.5%; n = 33) for seizure and 99.7% (IQR: 98.9–99.8%; n = 70) for nonseizure EEG. Analysis of events showed a median agreement of 83.0% (IQR: 72.9–86.6%; n = 33) for seizures with 0.018 disagreements per hour (IQR: 0.000–0.090 per hour; n = 70). Observers were more likely to disagree when a seizure was less than 30 sec. Overall, 33 neonates were diagnosed with seizures and 28 neonates were not, by all three observers. Of the remaining nine neonates with contradictory EEG detections, seven presented with low total seizure burden.

Interpretation

The IOA is high among experts for the detection of neonatal seizures using conventional, multichannel EEG. Agreement is reduced when seizures are rare or have short duration. These findings support EEG‐based decision making in the neonatal intensive care unit, inform EEG interpretation guidelines, and provide benchmarks for seizure detection algorithms.

Neurodevelopmental outcomes in preschool survivors of the Fontan procedure

OBJECTIVES

The study objectives were to compare the neurodevelopmental outcomes of preschool survivors of the Fontan procedure with those of children with congenital heart disease undergoing biventricular repair and to investigate predictors of neurodevelopmental outcome for those with single ventricle congenital heart disease, including hypoplastic left heart syndrome.

METHODS

Neurodevelopmental outcomes were assessed at 4 years of age, including cognition, visual-motor integration, behavior, social skills, and academic achievement. Unadjusted outcomes were compared between patients with biventricular circulation and patients with single ventricles. Predictors of neurodevelopmental outcome were assessed in the patients with single ventricles. Multiple covariate models were evaluated using patient-related, operative, and postoperative covariates.

RESULTS

Neurodevelopmental evaluation was performed in 365 children, 112 after the Fontan procedure (hypoplastic left heart syndrome, n = 91; other single ventricle, n = 21) and 253 after biventricular repair. Compared with patients with biventricular circulation, patients with single ventricles performed worse in terms of processing speed, inattention, and impulsivity. Otherwise, there were no significant differences between the groups for any domain. There was a trend toward lower performance for patients with single ventricles on visual motor integration. Outcomes for patients with hypoplastic left heart syndrome were not worse than for other forms of functional single ventricle. Patient factors were more important predictors of neurodevelopmental outcomes than were operative management variables.

CONCLUSIONS

In this cohort, unadjusted neurodevelopmental outcomes for preschool survivors of the Fontan procedure are similar to those for children with congenital heart disease undergoing biventricular repair for most domains. Among the patients undergoing the Fontan procedure, hypoplastic left heart syndrome was not associated with worse outcomes compared with other forms of single ventricle.

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.

Plasma topiramate concentrations resulting from doses associated with neuroprotection against white matter injury and stroke in two strains of rat pups

BACKGROUND

Cerebral white matter (WM) injury and stroke are common neuropathological injuries in newborns with congenital heart defects (CHDs) requiring surgery. Previous investigations in Long Evans rat pups subjected to hypoxia-ischemia found that intraperitoneal (i.p.) topiramate (TPM) at 30 mg/kg, but not 50 mg/kg, conferred neuroprotection. In Sprague-Dawley pups, a dose of 30 mg/kg protected against stroke. Concentrations associated with neuroprotective doses were not measured. The aims of this investigation were to determine concentrations associated with neuroprotective doses and to investigate the pharmacokinetics (PK) of i.p. TPM.

METHODS

Concentration-time data following administration of 30 and 50 mg/kg doses were analyzed using nonlinear mixed-effect modeling.

RESULTS

Mean predicted steady-state maximum and average concentrations following 30 mg/kg TPM were 31.3 and 16.8 μg/ml in Long Evans and 39.9 and 24.4 μg/ml in Sprague-Dawley pups. Mean predicted steady-state maximum and average concentrations following 50 mg/kg TPM were 52.1 and 28.1 μg/ml in Long Evans and 66.5 and 40.6 μg/ml in Sprague-Dawley pups. The apparent clearance (CL/F) and apparent volume of distribution (V/F) were 0.0470 ml/min and 22.2 ml, respectively, for Long Evans and 0.0325 ml/min and 19.7 ml, respectively, for Sprague-Dawley pups.

CONCLUSION

TPM concentrations associated with neuroprotective doses were determined. Body size and strain were significant covariates on CL/F and V/F. Results provide targets for future neuroprotection studies.

Results of genome-wide analyses on neurodevelopmental phenotypes at four-year follow-up following cardiac surgery in infancy

BACKGROUND

Adverse neurodevelopmental sequelae are reported among children who undergo early cardiac surgery to repair congenital heart defects (CHD). APOE genotype has previously been determined to contribute to the prediction of these outcomes. Understanding further genetic causes for the development of poor neurobehavioral outcomes should enhance patient risk stratification and improve both prevention and treatment strategies.

METHODS

We performed a prospective observational study of children who underwent cardiac surgery before six months of age; this included a neurodevelopmental evaluation between their fourth and fifth birthdays. Attention and behavioral skills were assessed through parental report utilizing the Attention Deficit-Hyperactivity Disorder-IV scale preschool edition (ADHD-IV), and Child Behavior Checklist (CBCL/1.5-5), respectively. Of the seven investigated, three neurodevelopmental phenotypes met genomic quality control criteria. Linear regression was performed to determine the effect of genome-wide genetic variation on these three neurodevelopmental measures in 316 subjects.

RESULTS

This genome-wide association study identified single nucleotide polymorphisms (SNPs) associated with three neurobehavioral phenotypes in the postoperative children ADHD-IV Impulsivity/Hyperactivity, CBCL/1.5-5 PDPs, and CBCL/1.5-5 Total Problems. The most predictive SNPs for each phenotype were: a LGALS8 intronic SNP, rs4659682, associated with ADHD-IV Impulsivity (P=1.03 × 10(-6)); a PCSK5 intronic SNP, rs2261722, associated with CBCL/1.5-5 PDPs (P=1.11 × 10(-6)); and an intergenic SNP, rs11617488, 50 kb from FGF9, associated with CBCL/1.5-5 Total Problems (P=3.47 × 10(-7)). 10 SNPs (3 for ADHD-IV Impulsivity, 5 for CBCL/1.5-5 PDPs, and 2 for CBCL/1.5-5 Total Problems) had p<10(-5).

CONCLUSIONS

No SNPs met genome-wide significance for our three neurobehavioral phenotypes; however, 10 SNPs reached a threshold for suggestive significance (p<10(-5)). Given the unique nature of this cohort, larger studies and/or replication are not possible. Studies to further investigate the mechanisms through which these newly identified genes may influence neurodevelopment dysfunction are warranted.

Younger gestational age is associated with worse neurodevelopmental outcomes after cardiac surgery in infancy

OBJECTIVE

Evaluate the impact of near-term delivery on neurodevelopmental (ND) outcomes in children with congenital heart disease (CHD).

METHODS

Secondary analysis of data from a study of genetic polymorphisms and ND outcomes after cardiac surgery in infants. The effect of gestational age (GA) as a continuous variable on ND outcomes was evaluated using general linear regression models. GA was also evaluated as a categorical variable to seek a threshold for better outcomes. ND domains tested at 4 years of age included cognition, language skills, attention, impulsivity, memory, executive function, social competence, visual-motor, and fine-motor skills.

RESULTS

ND outcomes and GA were available for 378 infants. Median GA was 39 weeks (range, 28-42 weeks) with 351 born at 36 weeks or more (near-term/term). In univariate analysis of the near-term/term subgroup, older GA predicted better performance for cognition, visual-motor, and fine-motor skills. After covariate adjustment, older GA predicted better performance for fine-motor skills (P = .018). Performance for cognition, language, executive function, social skills, visual-motor, and fine-motor skills was better for those born at 39 to 40 weeks of GA or more versus those born at less than 39 weeks (all P < .05).

CONCLUSIONS

These findings are consistent with the hypothesis that delivery before 39 to 40 weeks of GA is associated with worse outcomes in patients with CHD. Early delivery of a child with CHD is often indicated because of maternal or fetal health issues. In the absence of these concerns, these data suggest that elective (or spontaneous) delivery at 39 to 40 weeks of GA is associated with better ND outcomes.

Impact of continuous EEG monitoring on clinical management in critically ill children

BACKGROUND

Continuous EEG (cEEG) monitoring is being used with increasing frequency in critically ill patients, most often to detect non-convulsive seizures. While cEEG is non-invasive and feasible in the critical care setting, it is also expensive and labor intensive, and there has been little study of its impact on clinical care. We aimed to determine prospectively the impact of cEEG on clinical management in critically ill children.

METHODS

Critically ill children (non-neonates) with acute encephalopathy underwent cEEG. Study enrollment and data collection were prospective.

RESULTS

100 children were studied. EEG monitoring led to specific clinical management changes in 59 children. These included initiating or escalating anti-seizure medications in 43 due to seizure detection, demonstrating that a specific event (subtle movement or vital sign change) was not a seizure in 21, or obtaining urgent neuroimaging that led to a clinical change in 3. In the remaining 41 children, cEEG ruled out the presence of non-convulsive seizures but did not lead to a specific change in clinical management.

CONCLUSIONS

EEG monitoring led to changes in clinical management in the majority of patients, suggesting it may have an important role in management of critically ill children. Further study is needed to determine whether the management changes elicited by cEEG improve outcome.

Short-term outcome prediction by electroencephalographic features in children treated with therapeutic hypothermia after cardiac arrest

BACKGROUND

Electroencephalographic (EEG) features may provide objective data regarding prognosis in children resuscitated from cardiac arrest (CA), but therapeutic hypothermia (TH) may impact its predictive value. We aimed to determine whether specific EEG features were predictive of short-term outcome in children treated with TH after CA, both during hypothermia and after return to normothermia.

METHODS

Thirty-five children managed with a standard clinical TH algorithm after CA were prospectively enrolled. EEG recordings were scored in a standardized manner and categorized. EEG category 1 consisted of continuous and reactive tracings. EEG category 2 consisted of continuous but unreactive tracings. EEG category 3 included those with any degree of discontinuity, burst suppression, or lack of cerebral activity. The primary outcome was unfavorable short-term outcome defined as Pediatric Cerebral Performance Category score of 4-6 (severe disability, vegetative, death) at hospital discharge. Univariate analyses of the association between EEG category and outcome was performed using logistic regression.

RESULTS

For tracings obtained during hypothermia, patients with EEGs in categories 2 or 3 were far more likely to have poor outcome than those in category 1 (OR 10.7, P = 0.023 and OR 35, P = 0.004, respectively). Similarly, for tracings obtained during normothermia, patients with EEGs in categories 2 or 3 were far more likely to have poor outcomes than those in category 1 (OR 27, P = 0.006 and OR 18, P = 0.02, respectively).

CONCLUSIONS

A simple EEG classification scheme has predictive value for short-term outcome in children undergoing TH after CA.

Levetiracetam for treatment of neonatal seizures

Neonatal seizures are often refractory to treatment with initial antiseizure medications. Consequently, clinicians turn to alternatives such as levetiracetam, despite the lack of published data regarding its safety, tolerability, or efficacy in the neonatal population. We report a retrospectively identified cohort of 23 neonates with electroencephalographically confirmed seizures who received levetiracetam. Levetiracetam was considered effective if administration was associated with a greater than 50% seizure reduction within 24 hours. Levetiracetam was initiated at a mean conceptional age of 41 weeks. The mean initial dose was 16 ± 6 mg/kg and the mean maximum dose was 45 ± 19 mg/kg/day. No respiratory or cardiovascular adverse effects were reported or detected. Levetiracetam was associated with a greater than 50% seizure reduction in 35% (8 of 23), including seizure termination in 7. Further study is warranted to determine optimal levetiracetam dosing in neonates and to compare efficacy with other antiseizure medications.

Nonconvulsive seizures are common in critically ill children

BACKGROUND

Retrospective studies have reported the occurrence of nonconvulsive seizures in critically ill children. We aimed to prospectively determine the incidence and risk factors of nonconvulsive seizures in critically ill children using predetermined EEG monitoring indications and EEG interpretation terminology.

METHODS

Critically ill children (non-neonates) with acute encephalopathy underwent continuous EEG monitoring if they met institutional clinical practice criteria. Study enrollment and data collection were prospective. Logistic regression analysis was utilized to identify risk factors for seizure occurrence.

RESULTS

One hundred children were evaluated. Electrographic seizures occurred in 46 and electrographic status epilepticus occurred in 19. Seizures were exclusively nonconvulsive in 32. The only clinical risk factor for seizure occurrence was younger age (p=0.03). Of patients with seizures, only 52% had seizures detected in the first hour of monitoring, while 87% were detected within 24 hours.

CONCLUSIONS

Seizures were common in critically ill children with acute encephalopathy. Most were nonconvulsive. Clinical features had little predictive value for seizure occurrence. Further study is needed to confirm these data in independent high-risk populations, to clarify which children are at highest risk for seizures so limited monitoring resources can be allocated optimally, and to determine whether seizure detection and management improves outcome.

Is cardiac diagnosis a predictor of neurodevelopmental outcome after cardiac surgery in infancy?

OBJECTIVES

To determine whether a cardiac diagnosis is a predictor of neurodevelopmental outcomes after infant cardiac surgery.

METHODS

Infants with ventricular septal defect (VSD), tetralogy of Fallot (TOF), transposition of the great arteries (TGA), and hypoplastic left heart syndrome (HLHS) in a study of apolipoprotein E (APOE) polymorphisms, and neurodevelopmental outcome underwent neurodevelopmental and genetic evaluation at 4 years of age. The domains tested included cognition, language, speech, memory, executive function, visual-motor, fine motor, and reading and math skills.

RESULTS

Testing was completed in 178 patients with normal genetic evaluations: VSD (n = 26), TOF (n = 44), TGA (n = 41), and HLHS (n = 67). No differences were found in gestational age, ethnicity, APOE genotype, socioeconomic status, or maternal education among groups. Patient age at the first surgery was significantly lower for patients with TGA and HLHS compared with those with TOF and VSD. The postoperative length of stay was significantly longer for HLHS than all other groups and for TGA compared with TOF and VSD. HLHS correlated significantly with the use of deep hypothermic circulatory arrest and multiple operations. The mean scores for each domain were within normal limits for all groups. Compared with the other patients, those with HLHS had significantly lower scores for cognition, fine motor skills, executive function, and math skills. No significant differences were found among the TGA, TOF or VSD patients for any domain. Significant impairments in at least 1 domain were identified in 8% (2/25) of patients with VSD, 20% (8/41) with TOF, 17% (7/41) with TGA, and 18% (12/65) with HLHS. After correction for the demographic, preoperative, and operative variables, no significant differences were found among the groups for any domain.

CONCLUSIONS

The mean scores for the neurodevelopmental outcomes domains tested were in the normal range for preschool children with no recognized genetic syndromes after surgery for VSD, TOF, TGA, and HLHS. In each diagnostic group, the number of children with impairments in at least 1 domain increased compared with the general population. Unadjusted neurodevelopmental outcomes for HLHS were lower for cognition, fine motor skills, executive function, and math skills compared with the other patients. After correction for the demographic, preoperative, and operative variables, no significant differences were found among the groups for any domain. The specific cardiac diagnosis determines a large portion of the variation in these covariates. Therefore, although HLHS did predict for poorer outcomes in some domains, it did not add predictive power to the other factors considered.

Genetic factors are important determinants of impaired growth after infant cardiac surgery

OBJECTIVES

We sought to estimate the prevalence and identify the predictors of impaired growth after infant cardiac surgery.

METHODS

We performed a secondary analysis of a prospective study of the role of apolipoprotein E gene polymorphisms on neurodevelopment in young children after infant cardiac surgery. Prevalence estimates for growth velocity were derived by using anthropometric measures (weight and head circumference) obtained at birth and at 4 years of age. Genetic evaluation was also performed. Growth measure z scores were calculated by using World Health Organization Child Growth Standards. Growth velocity was evaluated by using 2 different techniques: first by clustering the children into one of 3 growth velocity subgroups based on z scores (impaired growth, difference < -0.5 standard deviation; stable growth, difference of -0.5 to 0.5 standard deviation; and improving growth, difference > 0.5 SD) and second by using continuous difference scores. Statistical analyses were conducted with a combination of proportional odds models for the ordered categories and simple linear regression for the continuous outcomes.

RESULTS

Three hundred nineteen full-term subjects had complete anthropometric measures for weight and head circumference at birth and 4 years. The cohort was 56% male. Genetic examinations were available for 97% (309/319) of the cohort (normal, 74%; definite or suspected genetic abnormality, 26%). Frequency counts for weight categories were as follows: impaired growth, 37%; stable growth, 31%; and improving growth, 32%. Frequency counts for head circumference categories were as follows: impaired growth, 39%; stable growth, 28%; and improving growth, 33%. The presence of a definite or suspected genetic syndrome (P = .04) was found to be a predictor of impaired growth for weight but not for head circumference. When growth z scores were used as continuous outcomes, the apolipoprotein E epsilon2 allele was found to be predictive of lower z scores for both weight (P = .02) and head circumference (P = .03).

CONCLUSIONS

Impaired growth for both weight and head circumference is common (both >30%) in this cohort of children after infant cardiac surgery. Both the apolipoprotein E epsilon2 allele and the presence of a definite or suspected genetic syndrome were associated with impaired weight growth velocity. The apolipoprotein E epsilon2 allele was also associated with impaired growth velocity for head circumference. Persistent poor growth might have long-term implications for the health and development of children with congenital heart defects.

Amplitude-integrated electroencephalography in neonates

Conventional electroencephalography (EEG) has been used for decades in the neonatal intensive care unit for formulating neurologic prognoses, demonstrating brain functional state and degree of maturation, revealing cerebral lesions, and identifying the presence and number of electrographic seizures. However, both the immediate availability of conventional EEG and the expertise with which it is interpreted are variable. Amplitude-integrated EEG provides simplified monitoring of cerebral function, and is rapidly gaining popularity among neonatologists, with growing use in bedside decision making and inclusion criteria for randomized clinical studies. Nonetheless, child neurologists and neurophysiologists remain cautious about relying solely on this tool and prefer interpreting conventional EEG. The present review examines the technical aspects of generating, recording, and interpreting amplitude-integrated EEG and contrasts this approach with conventional EEG. Finally, several proposed amplitude-integrated EEG classification schemes are reviewed. A clear understanding of this emerging technology of measuring brain health in the premature or sick neonate is critical in modern care of the newborn infant.

Perioperative stroke in infants undergoing open heart operations for congenital heart disease

BACKGROUND

The prevalence of perioperative stroke in infants undergoing operations for congenital heart disease has not been well described. The objectives of this study were to determine the prevalence of stroke as assessed by postoperative brain magnetic resonance imaging (MRI), characterize the neuroanatomic features of focal ischemic injury, and identify risk factors for its development.

METHODS

Brain MRI was performed in 122 infants 3 to 14 days after cardiac operation with cardiopulmonary bypass, with or without deep hypothermic circulatory arrest. Preoperative, intraoperative, and postoperative data were collected. Risk factors were tested by logistic regression for univariate and multivariate associations with stroke.

RESULTS

Stroke was identified in 12 of 122 patients (10%). Strokes were preoperative in 6 patients and possibly intraoperative or postoperative in the other 6 patients, and were clinically silent except in 1 patient who had clinical seizures. Arterial-occlusive and watershed infarcts were identified with equal distribution in both hemispheres. Multivariate analysis identified lower birth weight, preoperative intubation, lower intraoperative hematocrit, and higher blood pressure at admission to the cardiac intensive care unit postoperatively as significant factors associated with stroke. Prematurity, younger age at operation, duration of cardiopulmonary bypass, and use of deep hypothermic circulatory arrest were not significantly associated with stroke.

CONCLUSIONS

The prevalence of stroke in infants undergoing operations for congenital heart disease was 10%, half of which occurred preoperatively. Most were clinically silent and undetected without neuroimaging. Mechanisms included thromboembolism and hypoperfusion, with patient-specific, procedure-specific, and postoperative contributions to increased risk.

Hyperglycaemia after Stage I palliation does not adversely affect neurodevelopmental outcome at 1 year of age in patients with single-ventricle physiology

OBJECTIVE

Hyperglycaemia has been associated with worse outcome following traumatic brain injury and cardiac surgery in adults. We have previously reported no relationship between early postoperative hyperglycaemia and worse neurodevelopmental outcome at 1 year following biventricular repair of congenital heart disease. It is not known if postoperative hyperglycaemia results in worse neurodevelopmental outcome after infant cardiac surgery for single-ventricle lesions.

METHODS

Secondary analysis of postoperative glucose levels in infants <6 months of age undergoing Stage I palliation for various forms of single ventricle with arch obstruction. The patients were enrolled in a prospective study of genetic polymorphisms and neurodevelopmental outcomes assessed at 1 year of age with the Bayley Scales of Infant Development-II yielding two indices: mental developmental index (MDI) and psychomotor developmental index (PDI).

RESULTS

Stage I palliation was performed on 162 infants with 13 hospital and 15 late deaths (17.3% 1-year mortality). Neurodevelopmental evaluation was performed in 89 of 134 (66.4%) survivors. Glucose levels at admission to the cardiac intensive care unit and during the first 48 postoperative hours were available for 85 of 89 (96%) patients. Mean admission glucose value was 274+/-91 mg dl(-1); the maximum was 291+/-90 mg dl(-1), with 69 of 85 (81%) patients having at least one glucose value >200 mg dl(-1). Only two patients had a value <50 mg dl(-1). Mean MDI and PDI scores were 88+/-16 and 71+/-18, respectively. There were no statistically significant correlations between initial, mean, minimum or maximum glucose measurements and MDI or PDI scores. Only delayed sternal closure resulted in a statistically significant relationship between initial, minimum and maximum glucose values within the context of a multivariate analysis of variance model.

CONCLUSIONS

Hyperglycaemia following Stage I palliation in the neonatal period was not associated with lower MDI or PDI scores at 1 year of age.

Electroencephalographic monitoring during hypothermia after pediatric cardiac arrest

BACKGROUND

Hypoxic ischemic brain injury secondary to pediatric cardiac arrest (CA) may result in acute symptomatic seizures. A high proportion of seizures may be nonconvulsive, so accurate diagnosis requires continuous EEG monitoring. We aimed to determine the safety and feasibility of long-term EEG monitoring, to describe electroencephalographic background and seizure characteristics, and to identify background features predictive of seizures in children undergoing therapeutic hypothermia (TH) after CA.

METHODS

Nineteen children underwent TH after CA. Continuous EEG monitoring was performed during hypothermia (24 hours), rewarming (12-24 hours), and then an additional 24 hours of normothermia. The tolerability of these prolonged studies and the EEG background classification and seizure characteristics were described in a standardized manner.

RESULTS

No complications of EEG monitoring were reported or observed. Electrographic seizures occurred in 47% (9/19), and 32% (6/19) developed status epilepticus. Seizures were nonconvulsive in 67% (6/9) and electrographically generalized in 78% (7/9). Seizures commenced during the late hypothermic or rewarming periods (8/9). Factors predictive of electrographic seizures were burst suppression or excessively discontinuous EEG background patterns, interictal epileptiform discharges, or an absence of the expected pharmacologically induced beta activity. Background features evolved over time. Patients with slowing and attenuation tended to improve, whereas those with burst suppression tended to worsen.

CONCLUSIONS

EEG monitoring in children undergoing therapeutic hypothermia after cardiac arrest is safe and feasible. Electrographic seizures and status epilepticus are common in this setting but are often not detectable by clinical observation alone. The EEG background often evolves over time, with milder abnormalities improving and more severe abnormalities worsening.

Apolipoprotein E genotype modifies the risk of behavior problems after infant cardiac surgery

OBJECTIVE

The goal was to evaluate polymorphisms of the APOE gene as modifiers of neurobehavioral outcomes for preschool-aged children with congenital heart defects, after cardiac surgery.

METHODS

A prospective observational study with neurodevelopmental evaluation between the fourth and fifth birthdays was performed. Attention and behavioral skills were assessed through parental report.

RESULTS

Parents of 380 children completed the neurobehavioral measures. Child Behavior Checklist scores for the pervasive developmental problem scale were in the at-risk or clinically significant range for 15% of the cohort, compared with 9% for the normative data (P < .00001). Attention problem scores were in the at-risk or clinically significant range for 12% of the cohort, compared with 7% for the normative data (P = .0002). The Attention-Deficit/Hyperactivity Disorder Rating Scale-IV, Preschool Version, was completed for 378 children; 30% scored in the clinically significant range for inattention and 22% for impulsivity. After adjustment for covariates, the APOE epsilon2 allele was significantly associated with higher scores (worse problems) for multiple Child Behavior Checklist indices, including somatic complaints (P = .009), pervasive developmental problems (P = .032), and internalizing problems (P = .009). In each case, the epsilon4 allele was associated with a better outcome. APOE epsilon2 carriers had impaired social skills, compared with epsilon4 carriers (P = .009).

CONCLUSIONS

For preschool-aged children with congenital heart defects requiring surgery, parental rating scales showed an increased prevalence of restricted behavior patterns, inattention, and impaired social interactions. The APOE epsilon2 allele was associated with increased behavior problems, impaired social interactions, and restricted behavior patterns.

Brain maturation is delayed in infants with complex congenital heart defects

OBJECTIVE

Small head circumferences and white matter injury in the form of periventricular leukomalacia have been observed in populations of infants with severe forms of congenital heart defects. This study tests the hypothesis that congenital heart defects delay in utero structural brain development.

METHODS

Full-term infants with hypoplastic left heart syndrome or transposition of the great arteries were prospectively evaluated with preoperative brain magnetic resonance imaging. Patients with independent risk factors for abnormal brain development (shock, end-organ injury, or intrauterine growth retardation) were excluded. Outcome measures included head circumferences and the total maturation score on magnetic resonance imaging. Total maturation score is a previously validated semiquantitative anatomic scoring system used to assess whole brain maturity. The total maturation score evaluates 4 parameters of maturity: (1) myelination, (2) cortical infolding, (3) involution of glial cell migration bands, and (4) presence of germinal matrix tissue.

RESULTS

The study cohort included 29 neonates with hypoplastic left heart syndrome and 13 neonates with transposition of the great arteries at a mean gestational age of 38.9 +/- 1.1 weeks. Mean head circumference was 1 standard deviation below normal. The mean total maturation score for the cohort was 10.15 +/- 0.94, significantly lower than reported normative data in infants without congenital heart defects, corresponding to a delay of 1 month in structural brain development.

CONCLUSION

Before surgery, term infants with hypoplastic left heart syndrome and transposition of the great arteries have brains that are smaller and structurally less mature than expected. This delay in brain development may foster susceptibility to periventricular leukomalacia in the preoperative, intraoperative, and postoperative periods.

Prediction of periventricular leukomalacia. Part I: Selection of hemodynamic features using logistic regression and decision tree algorithms

OBJECTIVE

Periventricular leukomalacia (PVL) is part of a spectrum of cerebral white matter injury which is associated with adverse neurodevelopmental outcome in preterm infants. While PVL is common in neonates with cardiac disease, both before and after surgery, it is less common in older infants with cardiac disease. Pre-, intra-, and postoperative risk factors for the occurrence of PVL are poorly understood. The main objective of the present work is to identify potential hemodynamic risk factors for PVL occurrence in neonates with complex heart disease using logistic regression analysis and decision tree algorithms.

METHODS

The postoperative hemodynamic and arterial blood gas data (monitoring variables) collected in the cardiac intensive care unit of Children's Hospital of Philadelphia were used for predicting the occurrence of PVL. Three categories of datasets for 103 infants and neonates were used-(1) original data without any preprocessing, (2) partial data keeping the admission, the maximum and the minimum values of the monitoring variables, and (3) extracted dataset of statistical features. The datasets were used as inputs for forward stepwise logistic regression to select the most significant variables as predictors. The selected features were then used as inputs to the decision tree induction algorithm for generating easily interpretable rules for prediction of PVL.

RESULTS

Three sets of data were analyzed in SPSS for identifying statistically significant predictors (p<0.05) of PVL through stepwise logistic regression and their correlations. The classification success of the Case 3 dataset of extracted statistical features was best with sensitivity (SN), specificity (SP) and accuracy (AC) of 87, 88 and 87%, respectively. The identified features, when used with decision tree algorithms, gave SN, SP and AC of 90, 97 and 94% in training and 73, 58 and 65% in test. The identified variables in Case 3 dataset mainly included blood pressure, both systolic and diastolic, partial pressures pO(2) and pCO(2), and their statistical features like average, variance, skewness (a measure of asymmetry) and kurtosis (a measure of abrupt changes). Rules for prediction of PVL were generated automatically through the decision tree algorithms.

CONCLUSIONS

The proposed approach combines the advantages of statistical approach (regression analysis) and data mining techniques (decision tree) for generation of easily interpretable rules for PVL prediction. The present work extends an earlier research [Galli KK, Zimmerman RA, Jarvik GP, Wernovsky G, Kuijpers M, Clancy RR, et al. Periventricular leukomalacia is common after cardiac surgery. J Thorac Cardiovasc Surg 2004;127:692-704] in the form of expanding the feature set, identifying additional prognostic factors (namely pCO(2)) emphasizing the temporal variations in addition to upper or lower values, and generating decision rules. The Case 3 dataset was further investigated in Part II for feature selection through computational intelligence.

Prediction of periventricular leukomalacia. Part II: Selection of hemodynamic features using computational intelligence

OBJECTIVE

The objective of Part II is to analyze the dataset of extracted hemodynamic features (Case 3 of Part I) through computational intelligence (CI) techniques for identification of potential prognostic factors for periventricular leukomalacia (PVL) occurrence in neonates with congenital heart disease.

METHODS

The extracted features (Case 3 dataset of Part I) were used as inputs to CI based classifiers, namely, multi-layer perceptron (MLP) and probabilistic neural network (PNN) in combination with genetic algorithms (GA) for selection of the most suitable features predicting the occurrence of PVL. The selected features were next used as inputs to a decision tree (DT) algorithm for generating easily interpretable rules of PVL prediction.

RESULTS

Prediction performance for two CI based classifiers, MLP and PNN coupled with GA are presented for different number of selected features. The best prediction performances were achieved with 6 and 7 selected features. The prediction success was 100% in training and the best ranges of sensitivity (SN), specificity (SP) and accuracy (AC) in test were 60-73%, 74-84% and 71-74%, respectively. The identified features when used with the DT algorithm gave best SN, SP and AC in the ranges of 87-90% in training and 80-87%, 74-79% and 79-82% in test. Among the variables selected in CI, systolic and diastolic blood pressures, and pCO(2) figured prominently similar to Part I. Decision tree based rules for prediction of PVL occurrence were obtained using the CI selected features.

CONCLUSIONS

The proposed approach combines the generalization capability of CI based feature selection approach and generation of easily interpretable classification rules of the decision tree. The combination of CI techniques with DT gave substantially better test prediction performance than using CI and DT separately.

Assessment of neonatal electroencephalography (EEG) background by conventional and two amplitude-integrated EEG classification systems

OBJECTIVE

To determine the agreement among conventional electroencephalography (CEEG) terminology background classification and a simple and an advanced amplitude-integrated EEG (aEEG) system, and to evaluate whether aEEG interpreter experience or electrographic seizures affect this agreement.

STUDY DESIGN

CEEG background was classified by traditional interpretive criteria for 144 neonatal recordings, from which a single channel was converted to aEEGs. These aEEGs were independently interpreted by neonatologists according to the simple and advanced classification systems.

RESULTS

Interreader agreement was better with the simple aEEG system compared with the advanced aEEG system (multirater kappa, 0.66 vs 0.44). Fair-to-moderate agreement was found between both of the aEEG classification systems and CEEG (simple: kappa, 0.34 to 0.45; advanced: kappa, 0.36 to 0.45). Agreement did not vary significantly based on the aEEG interpreter experience or the presence of seizures.

CONCLUSIONS

Neonatologists found better agreement using the simple aEEG system regardless of their expertise or the presence of seizures. This finding has implications for patient selection in future multicenter neonatal neuroprotection studies.

Inattention, hyperactivity, and school performance in a population of school-age children with complex congenital heart disease

INTRODUCTION

There is a growing interest in characterizing the neurodevelopmental outcomes of school-age survivors of cardiac surgery. The purpose of this study was to examine a population of 5- to 10-year-old children who underwent newborn cardiac surgery for complex congenital heart disease to characterize and assess risk factors for problems with inattention and hyperactivity, as well as the use of remedial school services.

PATIENTS AND METHODS

This study was a cross-sectional analysis of patients who underwent newborn cardiac surgery and were enrolled in a neuroprotection trial conducted at our institution between 1992 and 1997. Parents and teachers completed questionnaires for the school-age child to elicit information pertaining to the child's general health and academic performance. The severity of hyperactivity and inattention were assessed by using 2 standardized questionnaires (Attention-Deficit/Hyperactivity Disorder Rating Scale-IV and Behavior Assessment System for Children). In addition to calculating descriptive estimates of their occurrence, single-covariate logistic regression models were specified and tested by using 3 different outcomes (inattention, hyperactivity, and use of remedial school services) and 14 different covariates representing preoperative, intraoperative, and postoperative factors.

RESULTS

Data were obtained from parents and/or teachers for 109 children. Fifty-three (49%) were receiving some form of remedial academic services, and 15% were assigned to a special-education classroom. The number of children receiving clinically significant scores for inattention and hyperactivity on the Behavior Assessment System for Children was 3 to 4 times higher than observed in the general population. On the Attention-Deficit/Hyperactivity Disorder Rating Scale-IV, 30% of the parents reported high-risk scores for inattention and 29% reported high-risk scores for hyperactivity. No perioperative factors were statistically associated with adverse outcomes.

CONCLUSION

In this cohort of children with complex congenital heart disease, a significant proportion of the children were at risk for inattention and hyperactivity, and nearly half were using remedial school services. We did not identify any perioperative risk factors, which correlated with high-risk scores or the use of remedial school services. Ongoing neurodevelopmental follow-up and screening are recommended in this vulnerable population.

Neurodevelopmental outcomes after staged palliation for hypoplastic left heart syndrome

OBJECTIVE

The goal was to determine the relative effects of underlying genetic factors and current management strategies on neurodevelopmental disabilities among one-year old survivors of palliation for hypoplastic left heart syndrome.

METHODS

Children who underwent staged reconstruction for hypoplastic left heart syndrome and variants were assessed at 1 year of age by using a neuromuscular examination and the Bayley Scales of Infant Development II, which provide the Mental Development Index and the Psychomotor Development Index. The effects of perioperative, operative, and genetic variables on developmental scores were evaluated.

RESULTS

The median birth weight was 3.3 kg (range: 2.1-4.5 kg). Eight-three patients (94%) underwent multiple operations with cardiopulmonary bypass during the first year of life (median: 2 operations). Seven patients (8%) required extracorporeal membrane oxygenation. Twenty-five patients (28%) had a confirmed or suspected genetic syndrome. At 1 year of age, the neuromuscular examination results were abnormal or suspect for 57 patients (65%). The median Mental Development Index score was 90, and 10 patients (11%) had scores of <70 (2 SDs below the general population mean). The median Psychomotor Development Index score was 73, and 42 patients (48%) had scores of <70. In multivariate analyses, younger gestational age, the presence of a genetic syndrome, and the need for preoperative intubation had significant negative effects on neurodevelopmental outcomes. No association was found with operative factors, including duration of deep hypothermic circulatory arrest.

CONCLUSIONS

At 1 year of age, there was a significant incidence of neurodevelopmental disabilities in children with hypoplastic left heart syndrome and variants; motor scores were particularly concerning. Many children had suspected or confirmed genetic syndromes, which negatively affected neurodevelopmental outcomes. Surgical variables did not affect neurologic outcomes.

Characterization of neonatal seizures by conventional EEG and single-channel EEG

OBJECTIVE

To perform a detailed, contemporary temporal-spatial characterization of neonatal seizures (NS) and to compare conventional EEG (CEEG) to single-channel EEG for NS detection.

METHODS

Digitally recorded CEEGs were reviewed for NS characteristics (quantity, duration, location of onset, peak-to-peak amplitude). The presence and characteristics of each NS were simultaneously noted in a single, derived EEG channel (C3-->C4).

RESULTS

Eight hundred fifty-one seizures from 125 CEEGs recorded were analyzed. Mean seizure rate was 7.0 NS/h (range: 0.5-21). Mean seizure burden (percent time CEEG showed NS at any location) was 24.8% (range: 0.7-86.9). Seizure rate was only moderately correlated with seizure burden (Spearman coefficient=0.58). Eighty-one percent of NS originated from central-temporal or midline vertex electrodes. Seventy-eight percent of NS appeared in the C3-->C4 channel.

CONCLUSIONS

Accurate measurement of NS burden requires detailed temporal-spatial characterization. The theoretical ceiling of sensitivity for NS detection in the single EEG channel C3-->C4 is high. However, further processing the raw EEG in limited electrode arrays may reduce the sensitivity of NS detection.

SIGNIFICANCE

CEEG is the gold standard for NS detection. However, reduced montage EEG techniques are increasingly available. This detailed contemporary temporal-spatial characterization of NS evaluates the potential limitations of reduced montage techniques.

Sensitivity of amplitude-integrated electroencephalography for neonatal seizure detection

BACKGROUND

Conventional electroencephalography remains the gold standard for the diagnosis and quantification of neonatal seizures. However, amplitude-integrated electroencephalography (aEEG) is being introduced to neonatal intensive care as an adjunct for neonatal seizure detection.

OBJECTIVES

This study's purpose was to determine the sensitivity of neonatal seizure detection in a single electroencephalogram channel (C3-->C4), used to simulate the raw signal from which aEEG is derived. We also aimed to determine the sensitivity of seizure detection by neonatologists by using aEEG and to establish those neonatal seizure characteristics that are associated with their correct detection by aEEG.

METHODS

Conventional electroencephalograms with neonatal seizures were reviewed for electroencephalogram background and neonatal seizure characteristics (site of onset, duration, and peak-to-peak amplitude). The presence, duration, and peak-to-peak amplitude of each seizure were simultaneously noted in a single electroencephalogram channel (C3-->C4). aEEGs generated from this channel were reviewed for background and seizures by 6 neonatologists with varying aEEG interpretation expertise.

RESULTS

A total of 851 neonatal seizures from 125 conventional electroencephalograms were analyzed. The patients' conceptional ages were 34 to 50 weeks. Because 94% of the conventional electroencephalograms had > or = 1 neonatal seizure visible in C3-->C4, and 78% of all neonatal seizures appeared in the C3-->C4 channel, the theoretical sensitivity of seizure detection in a single electroencephalogram channel was high. However, seizures were briefer and lower in amplitude in C3-->C4 compared with conventional electroencephalography. Neonatologists identified seizures in 22% to 57% of the 125 records of neonatal seizure. They detected 12% to 38% of the 851 individual seizures. Multivariate analysis revealed that the appearance of seizures in C3-->C4, neonatal seizure duration, seizure amplitude, seizure count per hour, and neonatologists' experience with aEEG interpretation all correlated with neonatal seizure detection.

CONCLUSIONS

Even among physicians who have extensive experience, many neonatal seizures are difficult to detect on an aEEG, especially when they are infrequent, brief, or of low amplitude.

Late cardiopulmonary and musculoskeletal exercise performance after repair for total anomalous pulmonary venous connection during infancy

OBJECTIVES

We evaluated cardiopulmonary function at rest and during exercise in children after surgical repair for total anomalous pulmonary venous connection.

BACKGROUND

Long-term assessment of cardiopulmonary function during exercise in children after repair for total anomalous pulmonary venous connection during infancy is limited.

METHODS

Resting lung function and cardiopulmonary function during maximal ramp cycle ergometry were evaluated in 27 patients (age = 11 +/- 4 years, 20 were male). Peak oxygen consumption, ventilatory anaerobic threshold, and physical working capacity were compared with normal reference values. Neurologic assessment included neuromuscular function, inattentiveness, and hyperactivity. Patient- and procedure-related variables were assessed for association with peak oxygen consumption, ventilatory anaerobic threshold, and physical working capacity.

RESULTS

Compared with healthy children, peak oxygen consumption (88% +/- 16% of predicted) and ventilatory anaerobic threshold (91% +/- 21% of predicted) were mildly reduced. Chronotropic impairment was observed in 7 patients (32%). Patients with impaired resting lung mechanics were more likely to have impairment in peak oxygen consumption (P < .05). Breathing reserve was normal. Specific anatomy and all operative factors did not have a significant impact on overall exercise performance. Composite score for fine and gross motor function was associated with lower ventilatory anaerobic threshold (P < .05).

CONCLUSIONS

Exercise performance is mildly impaired at long-term follow-up after total anomalous pulmonary venous connection repair during infancy. Residual pulmonary abnormalities are common and associated with lower exercise performance. Neurologic abnormalities are evident in a subgroup, but the impact on late exercise performance is inconclusive.

Aortic morphometry and microcephaly in hypoplastic left heart syndrome

Microcephaly is a marker of abnormal fetal cerebral development, and a known risk factor for cognitive dysfunction. Patients with hypoplastic left heart syndrome have been found to have an increased incidence of abnormal neurodevelopmental outcomes. We hypothesized that reduced cerebral blood flow from the diminutive ascending aorta and transverse aortic arch in the setting of hypoplastic left heart syndrome may influence fetal growth of the brain. The purpose of our study, therefore, was to define the prevalence of microcephaly in full-term infants with hypoplastic left heart syndrome, and to investigate potential cardiac risk factors for microcephaly. We carried out a retrospective review of full-term neonates with hypoplastic left heart syndrome. Eligible patients had documented indexes of birth weight, and measurements of length, and head circumference, as well as adequate echocardiographic images for measurement of the diameters of the ascending aorta and transverse aortic arch. We used logistic regression for analysis of the data. A total of 129 neonates met the criteria for inclusion, with 15 (12%) proving to have microcephaly. The sizes of their heads were disproportionately smaller than their weights (p less than 0.001) and lengths (p less than 0.001) at birth. Microcephaly was associated with lower birth weight (p less than 0.001), lower birth length (p equal to 0.007), and a smaller diameter of the ascending aorta (p equal to 0.034), but not a smaller transverse aortic arch (p equal to 0.619), or aortic atresia (p equal to 0.969). We conclude that microcephaly was common in this cohort of neonates with hypoplastic left heart syndrome, with the size of the head being disproportionately smaller than weight and length at birth. Microcephaly was associated with a small ascending aorta, but not a small transverse aortic arch. Impairment of somatic growth may be an additional factor in the development of microcephaly in these neonates.

Patient characteristics are important determinants of neurodevelopmental outcome at one year of age after neonatal and infant cardiac surgery

OBJECTIVE

Many studies of neurodevelopmental outcomes after neonatal and infant cardiac surgery have focused on potentially modifiable risk factors for adverse outcomes, primarily intraoperative management strategies and the use of deep hypothermic circulatory arrest. There is increasing evidence that patient-specific factors are more important determinants of outcome.

METHODS

We investigated predictors of neurodevelopmental outcomes at 1 year of age after neonatal and infant cardiac surgery in a subgroup of infants enrolled in a prospective study of apolipoprotein E (APOE) genotype and neurodevelopmental outcome. Children with a variety of 2-ventricle cardiac defects repaired with only 1 operation with cardiopulmonary bypass and no more than 1 episode of deep hypothermic circulatory arrest were included. Neurodevelopmental outcomes at 1 year of age included the Bayley Scales of Infant Development-II, which yield 2 indices, the Mental Developmental Index and the Psychomotor Developmental Index.

RESULTS

Two hundred forty-seven infants underwent surgical repair between October 1998 and April 2003 with 1 hospital death and 3 deaths before 1 year of age. Neurodevelopmental evaluation was performed in 188 (77%) of 243 survivors, including 56 patients with tetralogy of Fallot, 39 with transposition of the great arteries with intact ventricular septum, 34 with ventricular septal defects, and 59 with other defects. The median age at operation was 56 days (1-186 days), including 72 (38%) neonates. Confirmed or suspected genetic syndromes were present in 59 (31%) of 188 infants. Deep hypothermic circulatory arrest was used in 67 (35%) infants with a median duration of 34 minutes (1-80 minutes). For the entire cohort, the mean Mental Developmental Index was 90.6 +/- 14.9 and the mean Psychomotor Developmental Index was 81.6 +/- 17.2. For patients without genetic syndromes, the mean Mental Developmental Index was 93.7 +/- 13.6 and the mean Psychomotor Developmental Index was 85.1 +/- 14.6. For the entire cohort, predictors of lower scores for both the Mental Developmental Index and Psychomotor Developmental Index were presence of a confirmed or suspected genetic syndrome, lower birth weight, and presence of the APOE epsilon2 allele (all P < .04). Black race was associated with higher scores on the Psychomotor Developmental Index (P = .018). Lower nasopharyngeal temperature during cardiopulmonary bypass was associated with a lower score on the Psychomotor Developmental Index (P = .03) and was the only intraoperative factor that was a significant predictor of either the Mental or Psychomotor Developmental Index.

CONCLUSIONS

The strongest predictors of a worse neurodevelopmental outcome at 1 year of age were patient-specific factors including presence of a genetic syndrome, low birth weight, and presence of the APOE epsilon2 allele. Patient-specific factors eclipsed the use and duration of deep hypothermic circulatory arrest as predictors of worse neurodevelopmental outcomes.

The newborn drug development initiative workshop: Summary proceedings from the neurology group on neonatal seizures

BACKGROUND

The neonatal period eclipses all other epochs of the human life span for the highest incidence of seizures. Neonatal seizures are most commonly incited by serious acute illnesses such as hypoxic-ischemic encephalopathy, birth trauma, or infection.

OBJECTIVE

The goal of this article was to summarize some of the Neurology Group's discussion on neonatal seizures and their treatment with phenobarbital (PB).

METHODS

Information for this article was gathered from a workshop held March 29 and 30, 2004, in Baltimore, Maryland, as part of the Newborn Drug Development Initiative. A group of national experts was invited to form the Neurology Group to review certain aspects of neonatal seizures. Literature reviews were conducted using MEDLINE searches for original research studies, commentaries, and review articles between 1980 and 2004 using the key words neonatal seizures, treatment, and phenobarbital.

RESULTS

It has been empirically established that infants who experience seizures face substantially higher mortality and morbidity rates than those who do not. Basic research indicates that neonatal seizures themselves are not innocuous and actively contribute to adverse neurodevelopmental outcomes. Current worldwide clinical practice most often includes empiric treatment with PB for definite or suspected seizures in the newborn. Unfortunately, this common practice has never been proven by even a single, rigorous, randomized controlled trial. The Neurology Group identified the treatment of neonatal seizures with PB as an important topic in the practice of neonatal neurology for further investigation. Three possible frameworks for ethically acceptable, clinical treatment trials were explored. From these, a suitable scenario was selected-an electroencephalographer-blinded study of PB versus placebo in a homogeneous group of newborns who are at high risk of developing early subclinical electroencephalographic neonatal seizures (ENSs). Prospective video-electroencephalogram monitoring performed immediately after an insult (such as major cardiac surgery for a serious congenital heart defect) would establish the presence and number of subclinical ENSs. For a brief period of time, neonates with subclinical ENSs would be randomized to PB (dosed to match the PB-binding characteristics of the individual) or placebo. Clear criteria for escape from the study to active treatment are defined.

CONCLUSION

The investigation proposed here could refute or confirm the contemporary practice of PB administration as the first-line treatment of neonatal seizures.

Prolonged electroencephalogram monitoring for seizures and their treatment

This article reviews the diagnosis of neonatal seizures using routine electroencephalogram (EEG) examinations and long-term EEG monitoring. EEG is considered the gold standard for identifying the presence and quantifying the burden of neonatal seizures. The most common medication used to treat neonatal seizures is phenobarbital, although its efficacy has never been demonstrated by a formal, randomized, placebo-controlled drug trial.

Dystrophic neuritic processes in epileptic cortex

Cortical dysplasia is a frequent finding in cortical resections from children with refractory epilepsy. Diagnostic criteria and a classification scheme for cortical dysplasia has been proposed, though the relationship between specific cortical dysplasia features and their causal relationship with epilepsy is poorly understood. We reviewed 28 surgical resections from children and identified a common and easily recognized feature of cortical dysplasia: maloriented, misshapen and occasionally coarse neurofilament stained process forming a dystrophic neuritic background. The dystrophic neuritic background was associated with other features of cortical dysplasia in all 28 patients with cortical dysplasia, 26 with refractory epilepsy and 2 patients with other neurologic diagnoses. In seven children with refractory epilepsy due to other pathologic diagnosis such as vascular or glial lesions, the dystrophic neuritic background was only found in one patient with a ganglioglioma and other features suggestive of an associated cortical dysplasia. Our data indicate that a dystrophic neuritic background is a common and relatively specific neuropathologic finding in cortical dysplasia.

Neurodevelopmental outcome after early repair of a ventricular septal defect with or without aortic arch obstruction

OBJECTIVES

Cross-sectional studies of intermediate-term survivors of infant cardiac surgery have revealed a high frequency of neurodevelopmental disabilities. Few data exist regarding neurodevelopmental outcome of infants undergoing surgical intervention for a ventricular septal defect. The purpose of this study was to evaluate the neurodevelopmental outcome at 1 year of age of children who had surgical repair in infancy of a ventricular septal defect or a ventricular septal defect with aortic arch obstruction.

METHODS

Children who underwent repair of a ventricular septal defect or single-stage repair of a ventricular septal defect with aortic arch obstruction at less than 6 months of age were assessed at 1 year of age by using the Bayley Scales of Infant Development II, which yields the Mental Development Index and the Psychomotor Development Index, both with an expected mean of 100 +/- 15.

RESULTS

At 1 year, 55 patients (ventricular septal defect alone = 36; ventricular septal defect with aortic arch obstruction = 19) returned for evaluation. The mean Mental Development Index was 92.6 +/- 11.7, with 3 (5%) patients scoring 70 or less. The mean Psychomotor Development Index was 86.1 +/- 16.4, with 10 (18%) patients scoring 70 or less. Patients with a suspected or confirmed genetic syndrome had both a lower Mental Development Index score (P = .011) and a lower Psychomotor Development Index score (P = .001). Mental Development Index and Psychomotor Development Index were independent of anatomic (specifically aortic arch obstruction) and intraoperative factors (specifically deep hypothermic circulatory arrest).

CONCLUSIONS

Neurodevelopmental outcome at 1 year of age was within the normal limits for most patients who underwent repair of a ventricular septal defect or a ventricular septal defect with aortic arch obstruction during infancy.

Summary proceedings from the neurology group on neonatal seizures

One of the highest risk periods for seizures during the human life span is the first month of life. Most neonatal seizures are triggered by acute illness such as hypoxic-ischemic encephalopathy, stroke, or infection; rarely are they triggered by epilepsy per se. Seizures are the most common and important sign of acute neonatal encephalopathy, are a major risk for death or subsequent neurologic disability, and by themselves may contribute to an adverse neurodevelopmental outcome. Customary clinical practice includes visual monitoring of high-risk neonates for seizures, performance of a routine electroencephalogram (EEG) for suspicious clinical seizure activity, and empirical treatment with phenobarbital. Presently, however, there are no data that have unequivocally demonstrated the efficacy of barbiturates in the treatment of neonatal seizures. The neurology group recognizes an important need for randomized, placebo-controlled, ethically acceptable trials of phenobarbital efficacy and safety in the treatment of neonatal seizures. After exploring 3 possible frameworks for clinical trials of phenobarbital in the treatment of neonatal seizures, the neurology group ultimately focused on a multicenter, placebo-controlled, electroencephalographer-blinded study of phenobarbital versus placebo in a homogeneous group of newborns who are at high risk of developing early subclinical electroencephalographically detected neonatal seizures. Continuous video-EEG monitoring would establish the presence and number of seizures. Criteria for escape from the study to treatment are clearly defined. The proposed study could provide the first concrete evidence of treatment efficacy because (1) it examines a homogeneous patient population, (2) the recognition and quantification of seizures rests solely on the gold standard of seizure detection (EEG), and (3) the dosing of phenobarbital is matched specifically to the phenobarbital-binding characteristics of the individual treated. This study would affirm or refute the common practice of phenobarbital as the first-line treatment of neonatal seizures.

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

OBJECTIVE

The occurrence of a seizure after the arterial switch operation is associated with a worse long-term neurodevelopmental outcome. The significance of seizures after neonatal and infant repair of other congenital heart defects is not known.

METHODS

A recent study at our institution demonstrated seizures documented by 48-hour electroencephalographic monitoring in 20 (11%) of 178 neonates and infants after surgery for complex congenital heart defects, including hypoplastic left heart syndrome or variants. The developmental outcomes of this cohort were evaluated at 1 year of age by using the Bayley Scales of Infant Development II, which yields 2 scores: the Mental Developmental Index and the Psychomotor Developmental Index.

RESULTS

Developmental evaluations were performed in 114 (70%) of 164 survivors, including 36 with hypoplastic left heart syndrome. Postoperative electroencephalographic seizures had occurred in 15 (13%) of 114 of the entire group and in 8 (22%) of 36 of those with hypoplastic left heart syndrome. For the entire cohort, the Mental Developmental Index was 92.3 +/- 13.5, and the Psychomotor Developmental Index was 79.9 +/- 18.8 for patients without seizures, compared with 90.3 +/- 10.7 and 74.4 +/- 19.3 for those with seizures (both P > .5). For the hypoplastic left heart syndrome subgroup, the Mental Developmental Index was 92.3 +/- 14.9, and the Psychomotor Developmental Index was 74.8 +/- 19.3 for patients with seizures, compared with 91.9 +/- 12.4 and 73.9 +/- 18.3 for those without seizures (both P > .5). A frontal onset of seizures was predictive of a lower score on the Psychomotor Developmental Index, but not on the Mental Developmental Index.

CONCLUSIONS

The occurrence of a seizure after cardiac operation is a marker of central nervous system injury. However, in this cohort of neonates and infants with complex congenital heart defects, the occurrence of a seizure was not predictive of a worse developmental outcome at 1 year of age as assessed by the Bayley Scales of Infant Development II.

Effect of congenital heart disease on neurodevelopmental outcomes within multiple-gestation births

OBJECTIVES

We sought to assess the effect of congenital heart disease requiring surgical intervention with cardiopulmonary bypass at 6 months of age or less on developmental outcomes and growth at 1 year of age while controlling for socioeconomic status, prematurity, home environment, and parental intelligence.

METHODS

We performed within-family comparison of 11 multiple-gestation births in which one child had congenital heart disease. At 1 year of age, the Bayley Scales of Infant Development II were administered, and growth parameters were assessed. Paired comparisons were made by using fixed effects regression conditioned on family.

RESULTS

The multiple-gestation subjects were mildly premature on average (mean gestational age, 35.4 +/- 3.0 weeks). At 1 year of age, children with congenital heart disease scored lower on the Mental Development Index (85.0 +/- 19.3 vs 93.9 +/- 16.0, P = .037) and the Psychomotor Development Index (76.6 +/- 16.9 vs 91.3 +/- 14.9, P = .015) on the Bayley Scales of Infant Development II than did their siblings without congenital heart disease. There were no differences between siblings in weight, height, or head circumference.

CONCLUSIONS

The presence of congenital heart disease requiring surgical intervention with cardiopulmonary bypass at 6 months of age or less is associated with a deficit in developmental achievement at 1 year of age, as measured by using the Bayley Scales of Infant Development II.

Increasing duration of deep hypothermic circulatory arrest is associated with an increased incidence of postoperative electroencephalographic seizures

OBJECTIVE

Electroencephalographic seizures have been shown to occur in 5% to 20% of neonates and infants after biventricular repair of a variety of cardiac defects. Occurrence of a seizure is a predictor of adverse long-term neurodevelopmental sequelae. The contemporary incidence of postoperative seizures after repair of cardiac defects such as hypoplastic left heart syndrome and other forms of single ventricle is not known.

METHODS

A prospective study of 178 patients less than 6 months of age undergoing cardiopulmonary bypass with or without deep hypothermic circulatory arrest (DHCA) was conducted at a single institution from September 2001 through March 2003 to identify postoperative seizures assessed by 48-hour continuous video electroencephalographic monitoring.

RESULTS

Cardiac defects included transposition of the great arteries with or without a ventricular septal defect (n = 12), ventricular septal defect with or without coarctation (n = 28), tetralogy of Fallot (n = 24), hypoplastic left heart syndrome or variant (n = 60), other functional single ventricle (n = 14), and other defects suitable for biventricular repair (n = 40). Median age at the time of the operation was 7 days (range, 1-188 days) and was 30 days or less in 110 (62%) patients. DHCA was used in 117 (66%) patients, with multiple episodes in 9 patients. Median total duration of DHCA was 40 minutes (range, 1-90 minutes). Electroencephalographic seizures were identified in 20 (11.2%) patients. Seizures occurred in 15 (14%) of 110 neonates and 5 (7%) of 68 older infants. Seizures occurred in 1 (4%) of 24 patients with tetralogy of Fallot, 1 (8%) of 12 with transposition of the great arteries, and 11 (18%) of 60 with hypoplastic left heart syndrome or variant. By stepwise logistic regression analysis, once increasing duration of total DHCA (P = .001) was considered, no other variable improved prediction of occurrence of a seizure. Patients with DHCA duration of more than 40 minutes had an increased incidence of seizures (14/58 [24.1%]) compared with those with a DHCA duration of 40 minutes or less (4/59 [6.8%], P = .04). The incidence of seizures for patients with a DHCA duration of 40 minutes or less was not significantly different from those in whom DHCA was not used (2/61 [3.3%], P = .38).

CONCLUSIONS

In the current era, continuous electroencephalographic monitoring demonstrates early postoperative seizures in 11.2% of a heterogeneous cohort of neonates and infants with complex congenital heart defects. Increasing duration of DHCA was identified as a predictor of seizures. However, the incidence of seizures in children with limited duration of DHCA was similar to that in infants undergoing continuous cardiopulmonary bypass alone.

Late neurodevelopmental outcome after repair of total anomalous pulmonary venous connection

Objective We sought to define the neurodevelopmental status of school-aged survivors of total anomalous pulmonary venous connection repaired during infancy. Methods All school-aged survivors of total anomalous pulmonary venous connection repair performed at a single institution were eligible. Thirty children returned for neurologic examination and neurodevelopmental testing. Results The median age at total anomalous pulmonary venous connection repair was 16 days (range, 1-141 days), and age at testing was 11 years (range, 6-19 years). Pulmonary venous return was supracardiac in 14 patients, infracardiac in 12 patients, cardiac in 3 patients, and mixed in 1 patient. Preoperative obstructed total anomalous pulmonary venous connection was present in 6 patients. Circulatory arrest was used in all repairs, with a median duration of 35 minutes (range, 17-55 minutes). At follow-up, microcephaly (head circumference <5%) was present in 28%. Neuromuscular examination was suspect or abnormal in 27%. Mean Full-scale IQ (95.3 +/- 18.5) and Verbal IQ (98.6 +/- 20.2) were not different from population norms, but Performance IQ (92.3 +/- 16.9) was significantly lower than population norms ( P = .02). Fine motor skills and visual-motor coordination were significantly impaired ( P < .01 for Grooved Pegboard and Test of Visual-Motor Integration). Patients with total anomalous pulmonary venous connection also had difficulty with tests of attention (Test of Everyday Attention for Children, P < .01), but results of tests of memory function were not significantly different from population norms. Conclusions School-aged survivors of infant total anomalous pulmonary venous connection repair exhibit a significant incidence of neurodevelopmental difficulties. Fine motor function, visual-motor integration, and attention are the most commonly affected domains. Evaluation of these children is indicated to identify those who are at risk for learning disabilities and who could benefit from early intervention.

Migrating partial seizures in infancy: expanding the phenotype of a rare seizure syndrome

PURPOSE

The constellation of early-onset, unprovoked, alternating electroclinical seizures and neurodevelopmental devastation was first described by Coppola et al. We report six new patients and the prospect of a more optimistic developmental outcome.

METHODS

Retrospective chart reviews were performed on six infants evaluated at the Children's Hospital of Philadelphia (five patients) and at Hershey Medical Center (one patient) who had electroclinically alternating seizures before age 6 months of age. Electroclinical characteristics and long-term follow-up were recorded.

RESULTS

All had unprovoked, early-onset (range, 1 day to 3 months; mean, 25 days) intractable electroclinical seizures that alternated between the two hemispheres. Each patient underwent comprehensive brain imaging and neurometabolic workups, which were unrevealing. In all patients, subsequently intractable partial seizures developed and often a progressive decline of head circumference percentile occurred with age. Three demonstrated severe developmental delay and hypotonia. All survived, and 7-year follow-up on one patient was quite favorable.

CONCLUSIONS

Our patients satisfied the seven major diagnostic criteria first described by Coppola et al. The prognosis of this rare neonatal-onset epilepsy syndrome from the original description and subsequent case reports was very poor, with 28% mortality, and the majority of survivors were profoundly retarded and nonambulatory. Our patient data validate the diagnostic criteria of this syndrome and further quantify a previously described observation of progressive decline of head circumference percentiles with age. Our data also suggest that the prognosis of this syndrome, although poor, is not as uniformly grim as the cases reported previously in the literature.

Electrographic Neonatal Seizures after Infant Heart Surgery

PURPOSE

Neonatal seizures are relatively common and an important early sign of acute encephalopathy in those who survive infant heart surgery. The contemporary occurrence of seizures in this setting is not fully known, and their electrographic characteristics are incompletely described. This study describes the characteristics of electrographic neonatal seizures (ENSs) in contemporary infants with congenital heart disease (CHD) surgically repaired by using cardiopulmonary bypass, with or without deep hypothermic circulatory arrest.

METHODS

Consecutive infants undergoing heart surgery were monitored by video-EEG for 48 h postoperatively to establish the time of first seizure, total number of ENSs, site(s) of ENS(s) origin and other characteristics.

RESULTS

ENSs occurred in 21 (11.5%) of 183 infants. None had clinically visible seizures. The mean time to the first ENS was 21 h (range, 10-36 h). The total number of ENSs among the entire cohort was 1,429. Mean total number of ENSs per patient over a 48-h period was 72 (range, 1-217). Phenobarbital administration was associated with a > or =50% reduction in seizure counts in five (41.7%) of 12 subjects.

CONCLUSIONS

ENSs were relatively common in a large, contemporary cohort of infants after infant heart surgery. A wide variation was noted in seizure burden, but many experienced numerous seizures. Electrographic neonatal seizures are a candidate outcome end point in future neuroprotection trials in this patient population.

Preoperative cerebral blood flow is diminished in neonates with severe congenital heart defects

OBJECTIVE

Impaired neurodevelopmental outcome represents a major morbidity for survivors of infant heart surgery for congenital heart defects. Previous studies in these neonates have reported preoperative microcephaly, periventricular leukomalacia, and other findings. The hypothesis of this study is that preoperative cerebral blood flow is substantially diminished and might relate to preoperative neurologic conditions.

METHODS

Preoperative brain magnetic resonance imaging was performed. Cerebral blood flow measurements in infants with congenital heart defects were obtained by using a novel noninvasive magnetic resonance imaging technique, pulsed arterial spin-label perfusion magnetic resonance imaging. Cerebral blood flow was measured before the operation under standard ventilation and repeated after increased carbon dioxide.

RESULTS

A total of 25 term infants were studied. The average age at the time of the operation was 4.4 +/- 4.6 days. Congenital heart defects varied widely. Microcephaly occurred in 24% (6/25). Baseline cerebral blood flow was 19.7 +/- 9.2 mL . 100 g -1 . min -1 (8.0-42.2 mL . 100 g -1 . min -1 ). Five patients had cerebral blood flow measurements of less than 10 mL . 100 g -1 . min -1 . Mean hypercarbic cerebral blood flow increased to 40.1 +/- 20.3 mL . 100 g -1 . min -1 (11.4-94.0 mL . 100 g -1 . min -1 , P < .001). Pairwise analyses found that low hemoglobin levels were associated with higher baseline cerebral blood flow values ( P = .04). Periventricular leukomalacia occurred in 28% (7/25) and was associated with decreased baseline cerebral blood flow values ( P = .05) and a smaller change in cerebral blood flow with hypercarbia ( P = .003).

CONCLUSIONS

Structural brain abnormalities are common in these neonates before surgical intervention. Preoperative cerebral blood flow for this cohort was low and drastically reduced in some patients. Low cerebral blood flow values were associated with periventricular leukomalacia. Carbon dioxide reactivity was preserved but might be compromised by some aspects of the cardiac anatomy. The full spectrum of cerebral blood flow measurements with this technique in congenital heart defects and their long-term significance require continued investigation.

Periventricular leukomalacia is common after neonatal cardiac surgery

OBJECTIVES

Periventricular leukomalacia is necrosis of the cerebral white matter adjacent to the lateral ventricles and results from injury to immature oligodendroglia. In infants without congenital heart disease, periventricular leukomalacia is associated with an increased incidence of developmental delay and attention deficit/hyperactivity disorder. The incidence of periventricular leukomalacia and the risk factors for development of periventricular leukomalacia after infant cardiac surgery are not known.

METHODS

Magnetic resonance imaging of the brain was performed 6 to 14 days after cardiac surgery utilizing cardiopulmonary bypass with or without deep hypothermic circulatory arrest in 105 neonates and infants < or = 6 months of age.

RESULTS

Median age at surgery was 6 days (range 1-178), with 82 neonates (age < or = 30 days). Periventricular leukomalacia was found in 44 of the neonates (54%) compared with 1 of 23 infants (4%). Forward logistic regression using age at surgery as a continuous variable identified a model containing longer total support time (cardiopulmonary bypass plus deep hypothermic circulatory arrest), lower systolic blood pressure at cardiac intensive care unit admission postoperatively, lower minimum diastolic blood pressure, and Po(2) in the first 48 hours after surgery. When age at surgery was considered as a dichotomous variable (neonate versus infant), younger age at surgery replaced systolic blood pressure, Po(2), and total support time in the model. Lower minimum diastolic blood pressure was a significant risk factor in both models.

CONCLUSIONS

Periventricular leukomalacia was found in >50% of neonates after cardiac surgery but rarely in older infants. Hypoxemia and hypotension in the early postoperative period, particularly diastolic hypotension, may be important risk factors for periventricular leukomalacia.

Apolipoprotein E genotype and neurodevelopmental sequelae of infant cardiac surgery

BACKGROUND

There has been increasing recognition of adverse neurodevelopmental sequelae in some children after repair of congenital heart defects. Even among children with the same cardiac defect, significant interindividual variation exists in developmental outcome. Polymorphisms of apolipoprotein E have been identified as a risk factor for worse neurologic recovery after central nervous system injury.

METHODS

A single-institution prospective study of patients <or=6 months of age undergoing cardiopulmonary bypass for repair of congenital heart defects was undertaken to evaluate the association between apolipoprotein E genotype and postoperative neurodevelopmental dysfunction. Developmental outcomes were evaluated at 1 year of age by using the Bayley Scales of Infant Development.

RESULTS

One-year evaluation was performed in 244 patients. After adjustment for preoperative and postoperative covariates-including gestational age, age at operation, sex, race, socioeconomic status, cardiac defect, and use of deep hypothermic circulatory arrest-the apolipoprotein E epsilon2 allele was associated with a worse neurologic outcome as assessed by the Psychomotor Developmental Index of the Bayley Scales of Infant Development (P =.036). Patients with the apolipoprotein E epsilon2 allele had approximately a 7-point decrease in the Psychomotor Developmental Index.

CONCLUSIONS

Apolipoprotein E epsilon2 allele carriers had significantly lower Psychomotor Development Index scores at 1 year of age after infant cardiac surgery. The effect was independent of ethnicity, socioeconomic status, cardiac defect, and use of deep hypothermic circulatory arrest. An effect of the apolipoprotein E epsilon4 allele was not detected. Genetic polymorphisms that decrease neuroresiliency and impair neuronal repair after central nervous system injury are important risk factors for neurodevelopmental dysfunction after infant cardiac surgery.

Dysplasia: a common finding in intractable pediatric temporal lobe epilepsy

BACKGROUND

Risk factors for temporal lobe epilepsy (TLE) include history of CNS infection, family history of epilepsy, and history of febrile convulsions (FC). Pre-existing cortical dysplasia (CD) may also predispose to refractory TLE, independent of other risk factors for epilepsy.

METHODS

The authors reviewed the neuropathologic features of surgical tissue from temporal lobectomies of 33 pediatric patients with refractory TLE, with and without a history of epilepsy risk factors.

RESULTS

CD was found in 64% (21/33) of all patients with refractory TLE, including 73% (11/15) patients with a history of FC, 66% (2/3) patients with CNS infections, and 83% (5/6) patients with a family history of epilepsy. Disrupted cortical lamination, dystrophic and maloriented neurons, and balloon cells characterized the CD found in the temporal neocortex.

CONCLUSION

CD was seen in 21 of 33 surgical specimens from children with refractory TLE, including those with and without other epilepsy risk factors.