Usefulness of routine head ultrasound scans before surgery for congenital heart disease

Perioperative Neuromonitoring in Children with Congenital Heart Disease

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

Early brain magnetic resonance imaging findings and neurodevelopmental outcome in children with congenital heart disease: A systematic review

AIM

To investigate the association between early brain magnetic resonance imaging (MRI) findings and neurodevelopmental outcome (NDO) in children with congenital heart disease (CHD).

METHOD

A search for studies was conducted in Embase, Medline, Web of Science, Cochrane Central, PsycINFO, and Google Scholar. Observational and interventional studies were included, in which patients with CHD underwent surgery before 2 months of age, a brain MRI scan in the first year of life, and neurodevelopmental assessment beyond the age of 1 year.

RESULTS

Eighteen studies were included. Thirteen found an association between either quantitative or qualitative brain metrics and NDO: 5 out of 7 studies showed decreased brain volume was significantly associated with worse NDO, as did 7 out of 10 studies on brain injury. Scanning protocols and neurodevelopmental tests varied strongly.

INTERPRETATION

Reduced brain volume and brain injury in patients with CHD can be associated with impaired NDO, yet standardized scanning protocols and neurodevelopmental assessment are needed to further unravel trajectories of impaired brain development and its effects on outcome.

Optimizing Neurodevelopmental Outcomes in Neonates With Congenital Heart Disease

Neurodevelopmental impairment is a common and important long-term morbidity among infants with congenital heart disease (CHD). More than half of those with complex CHD will demonstrate some form of neurodevelopmental, neurocognitive, and/or psychosocial dysfunction requiring specialized care and impacting long-term quality of life. Preventing brain injury and treating long-term neurologic sequelae in this high-risk clinical population is imperative for improving neurodevelopmental and psychosocial outcomes. Thus, cardiac neurodevelopmental care is now at the forefront of clinical and research efforts. Initial research primarily focused on neurocritical care and operative strategies to mitigate brain injury. As the field has evolved, investigations have shifted to understanding the prenatal, genetic, and environmental contributions to impaired neurodevelopment. This article summarizes the recent literature detailing the brain abnormalities affecting neurodevelopment in children with CHD, the impact of genetics on neurodevelopmental outcomes, and the best practices for neonatal neurocritical care, focusing on developmental care and parental support as new areas of importance. A framework is also provided for the infrastructure and resources needed to support CHD families across the continuum of care settings.

Functional brain maturation and sleep organisation in neonates with congenital heart disease

OBJECTIVE

Neonates with Congenital Heart Disease (CHD) have structural delays in brain development. To evaluate whether functional brain maturation and sleep-wake physiology is also disturbed, the Functional Brain Age (FBA) and sleep organisation on EEG during the neonatal period is investigated.

METHODS

We compared 15 neonates with CHD who underwent multichannel EEG with healthy term newborns of the same postmenstrual age, including subgroup analysis for d-Transposition of the Great Arteries (d-TGA) (n = 8). To estimate FBA, a prediction tool using quantitative EEG features as input, was applied. Second, the EEG was automatically classified into the 4 neonatal sleep stages. Neonates with CHD underwent neurodevelopmental testing using the Bayley Scale of Infant Development-III at 24 months.

RESULTS

Preoperatively, the FBA was delayed in CHD infants and more so in d-TGA infants. The FBA was positively correlated with motor scores. Sleep organisation was significantly altered in neonates with CHD. The duration of the sleep cycle and the proportion of Active Sleep Stage 1 was decreased, again more marked in the d-TGA infants. Neonates with d-TGA spent less time in High Voltage Slow Wave Sleep and more in Tracé Alternant compared to healthy terms. Both FBA and sleep organisation normalised postoperatively. The duration of High Voltage Slow Wave Sleep remained positively correlated with motor scores in d-TGA infants.

INTERPRETATION

Altered early brain function and sleep is present in neonates with CHD. These results are intruiging, as inefficient neonatal sleep has been linked with adverse long-term outcome. Identifying how these rapid alterations in brain function are mitigated through improvements in cerebral oxygenation, surgery, drugs and nutrition may have relevance for clinical practice and outcome.

A low incidence of preoperative neurosonographic abnormalities in neonates with heart defects

BACKGROUND AND AIM

To investigate whether neonates with prenatally detected congenital heart defects (CHD) demonstrate cerebral abnormalities on early preoperative cranial ultrasound (CUS), compared to healthy neonates, and to measure brain structures to assess brain growth and development in both groups.

STUDY DESIGN, SUBJECTS AND OUTCOME MEASURES

Prospective cohort study with controls. Between September 2013 and May 2016 consecutive cases of prenatally detected severe isolated CHD were included. Neonatal CUS was performed shortly after birth, before surgery and in a healthy control group. Blinded images were reviewed for brain abnormalities and various measurements of intracranial structures were compared.

RESULTS

CUS was performed in 59 healthy controls and 50 CHD cases. Physiological CUS variants were present in 54% of controls and in 52% of CHD cases. Abnormalities requiring additional monitoring (both significant and minor) were identified in four controls (7%) and five CHD neonates (10%). Significant abnormalities were only identified in four CHD neonates (8%) and never in controls. A separate analysis of an additional 8 CHD neonates after endovascular intervention demonstrated arterial stroke in two cases that underwent balloon atrioseptostomy (BAS). Cerebral measurements were smaller in CHD neonates, except for the cerebrospinal fluid measurements, which were similar to the controls.

CONCLUSIONS

The prevalence of significant preoperative CUS abnormalities in CHD cases was lower than previously reported, which may be partially caused by a guarding effect of a prenatal diagnosis. Arterial stroke occurred only in cases after BAS. As expected, neonates with CHD display slightly smaller head size and cerebral growth.

Brain Development of Children With Single Ventricle Physiology or Transposition of the Great Arteries: A Longitudinal Observation Study

To define the correlation between neuroanatomic and developmental outcomes of children with single ventricle (SV) or transposition of the great arteries (TGA), a prospective longitudinal study was performed in preschool and school-age children. Twenty-seven children with congenital heart disease (9, TGA; 18, SV) were included. Participants underwent 3-dimensional magnetic resonance imaging (MRI) and neurodevelopmental assessment at around 3 years (preschool age) and at 9 years (school age), and 48 healthy controls underwent MRI, and their data were used to derive best-fit models for normal brain volumes for comparisons with congenital heart disease patients. Total brain volume (TBV) and regional brain volumes remained significantly smaller in SV children than in TGA children at both time points, though the growth slope of TBV was not significantly different between the SV and TGA groups. Although the psychomotor developmental index at preschool was significantly lower in SV patients, the full-scale IQ at school age was not significantly lower in SV patients. There was a strong correlation between full-scale IQ and TBV (r = 0.49, P = 0.005). Despite the current best practices, persistently lower TBV was seen in SV patients until 9 years of age. For both the SV and TGA groups, TBV at 3 years was a strong predictor of TBV at 9 years. Since there was a correlation between TBV and IQ at 9 years, identification of factors that affect brain growth until 3 years will be imperative to improve patients' cognitive function at school age.

Acute Neurologic Injury in Children Admitted to the Cardiac Intensive Care Unit

BACKGROUND

Children with acquired and congenital heart disease both have low mortality but an increased risk of neurologic morbidity that is multifactorial. Our hypothesis was that acute neurologic injuries contribute to mortality in such children and are an important cause of death.

METHODS

All admissions to the pediatric cardiac intensive care unit (CICU) from January 2011 through January 2015 were retrospectively reviewed. Patients were assessed for any acute neurologic events (ANEs) during admission, as defined by radiologic findings or seizures documented on an electroencephalogram.

RESULTS

Of the 1,573 children admitted to the CICU, the incidence of ANEs was 8.6%. Mortality of the ANE group was 16.3% compared with 1.5% for those who did not have an ANE. The odds ratio for death with ANEs was 8.55 (95% confidence interval, 4.56 to 16.03). Patients with ANEs had a longer hospital length of stay than those without ANEs (41.4 ± 4 vs 14.2 ± 0.6 days; p < 0.001). Need for extracorporeal membrane oxygenation, previous cardiac arrest, and prematurity were independently associated with the presence of an ANE.

CONCLUSIONS

Neurologic injuries are common in pediatric CICUs and are associated with an increase in mortality and hospital length of stay. Children admitted to the CICU are likely to benefit from improved surveillance and neuroprotective strategies to prevent neurologic death.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neurodevelopmental outcome of children with congenital heart disease

Congenital heart disease (CHD) constitutes the most common congenital malformation, with moderate or severe CHD occurring in around 6 in 1000 live births. Due to advances in medical care, survival rates have increased significantly. Thus, the majority of children with CHD survive until adolescence and adulthood. Children with CHD requiring cardiopulmonary bypass surgery are at risk for neurodevelopmental impairments in various domains, including mild impairments in cognitive and neuromotor functions, difficulties with social interaction, inattention, emotional symptoms, and impaired executive function. The prevalence for these impairments ranges from 20% to 60% depending on age and domain ("high prevalence-low severity"). Domains are often affected simultaneously, leading to school problems with the need for learning support and special interventions. The etiology of neurodevelopmental impairments is complex, consisting of a combination of delayed intrauterine brain development and newly occurring perioperative brain injuries. Mechanisms include altered intrauterine hemodynamic flow as well as neonatal hypoxia and reduced cerebral blood flow. The surgical procedure and postoperative phase add to this cascade of factors interfering with normal brain development. Early identification of children at high risk through structured follow-up programs is mandated to provide individually tailored early interventions and counseling to improve developmental health.

Alterations in cerebral ventricle size in children with congenital heart disease

PURPOSE

Children with tetralogy of Fallot (TOF) and superior cavopulmonary anastomoses (SCPA) can have chronically elevated central venous pressure (CVP), which has been postulated to put patients at risk for cerebral ventriculomegaly. We aimed to examine cerebral ventricle size in children with these congenital heart lesions before and after surgery to determine how changes in CVP affect ventricle size.

METHODS

We reviewed the records of patients who underwent SCPA or TOF repair between 2006 and 2015. Patients with pre- or post-operative cranial imaging were included. Frontal-occipital (FO) horn ratios were calculated as measures of cerebral ventricle volume. Reported normal mean FO ratio is 0.37 ± 0.03. Patient characteristics including occipito-fronto circumference (OFC) and available CVP measurements were recorded. CVP, FO ratios, and OFC percentiles were compared using paired and unpaired t tests and Wilcoxon matched pairs signed-rank test as appropriate.

RESULTS

We reviewed 44 patients who underwent SCPA and 31 patients who underwent TOF repair who had cranial imaging studies available. In the 22 patients who underwent SCPA and had pre- and post-operative imaging, mean FO ratios significantly increased from 0.37 ± 0.03 to 0.40 ± 0.04 (P < 0.001). In contrast, in the seven patients with TOF with pre- and post-operative imaging, FO ratio was elevated at baseline and remains so after surgical repair, 0.43 ± 0.08 to 0.42 ± 0.08 (P = 0.65). Similar patterns were noted with OFC percentiles, which were significantly increased as compared to baseline after SCPA (P < 0.001) but were not significantly changed after TOF repair (P = 0.58). Finally, when available, preoperative and postoperative CVP measurements of all patients were examined, CVP increased in patients who underwent SCPA, from 6.5 ± 2 mmHg preoperatively to 9.1 ± 2.3 mmHg postoperatively (P < 0.001), while CVP remained statistically unchanged in patients who underwent TOF repair, 12.9 ± 3.3 mmHg preoperatively to 14.4 ± 3.1 mmHg postoperatively (P = 0.2).

CONCLUSION

Cerebral ventriculomegaly was observed in patients with SCPA and TOF, and the observed changes in FO ratio and OFC may be related, at least in part, to CVP.

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

OBJECTIVE

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Intraventricular Hemorrhage in Moderate to Severe Congenital Heart Disease

OBJECTIVES

Determine the prevalence of intraventricular hemorrhage in infants with moderate to severe congenital heart disease, investigate the impact of gestational age, cardiac diagnosis, and cardiac intervention on intraventricular hemorrhage, and compare intraventricular hemorrhage rates in preterm infants with and without congenital heart disease.

DESIGN

A single-center retrospective review.

SETTING

A tertiary care children's hospital.

PATIENTS

All infants admitted to St. Louis Children's Hospital from 2007 to 2012 with moderate to severe congenital heart disease requiring cardiac intervention in the first 90 days of life and all preterm infants without congenital heart disease or congenital anomalies/known genetic diagnoses admitted during the same time period.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Cranial ultrasound data were reviewed for presence/severity of intraventricular hemorrhage. Head CT and brain MRI data were also reviewed in the congenital heart disease infants. Univariate analyses were undertaken to determine associations with intraventricular hemorrhage, and a final multivariate logistic regression model was performed. There were 339 infants with congenital heart disease who met inclusion criteria and 25.4% were born preterm. Intraventricular hemorrhage was identified on cranial ultrasound in 13.3% of infants, with the majority of intraventricular hemorrhage being low-grade (grade I/II). The incidence increased as gestational age decreased such that intraventricular hemorrhage was present in 8.7% of term infants, 19.2% of late preterm infants, 26.3% of moderately preterm infants, and 53.3% of very preterm infants. There was no difference in intraventricular hemorrhage rates between cardiac diagnoses. Additionally, the rate of intraventricular hemorrhage did not increase after cardiac intervention, with only three infants demonstrating new/worsening high-grade (grade III/IV) intraventricular hemorrhage after surgery. In a multivariate model, only gestational age at birth and African-American race were predictors of intraventricular hemorrhage. In the subset of infants with CT/MRI data, there was good sensitivity and specificity of cranial ultrasound for presence of intraventricular hemorrhage.

CONCLUSIONS

Infants with congenital heart disease commonly develop intraventricular hemorrhage, particularly when born preterm. However, the vast majority of intraventricular hemorrhage is low-grade and is associated with gestational age and African-American race.

Brain Injury and Neurodevelopmental Outcome in Congenital Heart Disease: A Systematic Review

CONTEXT

Brain injury during prenatal and preoperative postnatal life might play a major role in neurodevelopmental impairment in infants with congenital heart disease (CHD) who require corrective or palliative surgery during infancy. A systematic review of cerebral findings during this period in relation to neurodevelopmental outcome (NDO), however, is lacking.

OBJECTIVE

To assess the association between prenatal and postnatal preoperative cerebral findings and NDO in infants with CHD who require corrective or palliative surgery during infancy.

DATA SOURCES

PubMed, Embase, reference lists.

STUDY SELECTION

We conducted 3 different searches for English literature between 2000 and 2016; 1 for prenatal cerebral findings, 1 for postnatal preoperative cerebral findings, and 1 for the association between brain injury and NDO.

DATA EXTRACTION

Two reviewers independently screened sources and extracted data on cerebral findings and neurodevelopmental outcome. Quality of studies was assessed using the Newcastle-Ottawa Quality Assessment Scale.

RESULTS

Abnormal cerebral findings are common during the prenatal and postnatal preoperative periods. Prenatally, a delay of cerebral development was most common; postnatally, white matter injury, periventricular leukomalacia, and stroke were frequently observed. Abnormal Doppler measurements, brain immaturity, cerebral oxygenation, and abnormal EEG or amplitude-integrated EEG were all associated with NDO.

LIMITATIONS

Observational studies, different types of CHD with different pathophysiological effects, and different reference values.

CONCLUSIONS

Prenatal and postnatal preoperative abnormal cerebral findings might play an important role in neurodevelopmental impairment in infants with CHD. Increased awareness of the vulnerability of the young developing brain of an infant with CHD among caregivers is essential.

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

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

Stroke in Acquired and Congenital Heart Disease Patients and Its Relationship to Hospital Mortality and Lasting Neurologic Deficits

OBJECTIVE

To describe strokes in patients with acquired or congenital heart disease and investigate risk factors for in-hospital mortality and ongoing neurologic deficits.

DESIGN

Single-center, retrospective review of cardiac, neurologic, and radiologic patient databases.

SETTING

Tertiary care children's hospital.

PATIENTS

All patients with acquired or congenital heart disease admitted from January 2010 to October 2014 identified with stroke.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Eighty-four stroke events were identified in 83 patients (median age, 5.9 mo; interquartile range, 0.8-33.4). Thirty-two patients (38%) had single ventricle congenital heart disease. Eight patients (9%) presented with symptoms at home, and the remainder was diagnosed while already admitted to the hospital. Forty patients (48%) presented with clinically evident neurologic deficits (e.g., weakness, seizures). Fifty-eight patients (69%) had arterial ischemic strokes, and 13 (15%) had parenchymal hemorrhages. At diagnosis, 54 patients (64%) were on inotropes. Twenty-nine patients (35%) had greater than or equal to 3 cardiac procedures during their hospitalization before stroke diagnosis. In-hospital mortality occurred in 28 patients (33%). Under multivariate analysis, inotropes, number of cardiac procedures, lack of seizure, and parenchymal hemorrhage were independently associated with in-hospital mortality (p < 0.05). Fifty-four percent of survivors with neurologic follow-up had ongoing neurologic deficits attributable to strokes (median follow-up, 15.3 mo; interquartile range, 7.0-29.9). With multivariate analysis, longer hospital stay (p = 0.02) was independently associated with ongoing deficits.

CONCLUSIONS

A majority of patients with acquired or congenital heart disease who suffer stroke present while hospitalized and without focal neurologic findings. In-hospital mortality is associated with inotropes, cardiac procedures, lack of seizure, and parenchymal hemorrhage. The majority of survivors have lasting neurologic deficits associated with longer hospital stay.

Cerebral ventriculomegaly after the bidirectional Glenn (BDG) shunt: a single-institution retrospective analysis

PURPOSE

The bidirectional Glenn (BDG) procedure involves the anastomosis of the superior vena cava (SVC) to the pulmonary artery, increasing central venous pressure (CVP). We hypothesize that this increase in CVP triggers an acute neurologic insult, leading to ventriculomegaly.

METHODS

In this retrospective analysis in a tertiary care children's hospital, we identified 167 patients who underwent the BDG procedure between August 2006 and July 2013. Within this initial cohort, 24 patients had head imaging (CT, MRI, or ultrasound) performed both before and after the BDG.

RESULTS

From head imaging available from these 24 patients, we measured the frontal-occipital horn ratio (FOR), a well-validated measure of lateral ventricle size. Using central venous catheter data, we assessed postoperative CVP at 12, 24, and 48 h. Paired t tests and linear regression were used to evaluate our cohort. Median age at surgery was 4.9 months. Paired analysis revealed that median FOR significantly increased between preoperative (median 0.38, IQR 0.37-0.41) and postoperative (median 0.42, IQR 0.40-0.45) head images (p = 0.005). Increasing change in FOR was associated with increased 12-h (R(2) = 0.369, p = 0.003) but not 24- or 48-h postoperative CVP.

CONCLUSIONS

To our knowledge, our study is the first to demonstrate ventriculomegaly developing after the BDG. Physiologically, increasing CVP after the BDG was associated with greater change in lateral ventricle size. This supports the contention that increasing CVP produced during the BDG may damage the developing brain. This study has informed a prospective evaluation of a link between the BDG procedure and neurologic outcomes.

Scoring system for periventricular leukomalacia in infants with congenital heart disease

BACKGROUND

Currently two magnetic resonance imaging (MRI) methods have been used to assess periventricular leukomalacia (PVL) severity in infants with congenital heart disease: manual volumetric lesion segmentation and an observational categorical scale. Volumetric classification is labor intensive and the categorical scale is quick but unreliable. We propose the quartered point system (QPS) as a novel, intuitive, time-efficient metric with high interrater agreement.

METHODS

QPS is an observational scale that asks the rater to score MRIs on the basis of lesion size, number, and distribution. Pre- and postoperative brain MRIs were obtained on term congenital heart disease infants. Three independent observers scored PVL severity using all three methods: volumetric segmentation, categorical scale, and QPS.

RESULTS

One-hundred and thirty-five MRIs were obtained from 72 infants; PVL was seen in 48 MRIs. Volumetric measurements among the three raters were highly concordant (ρc = 0.94-0.96). Categorical scale severity scores were in poor agreement between observers (κ = 0.17) and fair agreement with volumetrically determined severity (κ = 0.26). QPS scores were in very good agreement between observers (κ = 0.82) and with volumetric severity (κ = 0.81).

CONCLUSION

QPS minimizes training and sophisticated radiologic analysis and increases interrater reliability. QPS offers greater sensitivity to stratify PVL severity and has the potential to more accurately correlate with neurodevelopmental outcomes.

Can preoperative cranial ultrasound predict early neurodevelopmental outcome in infants with congenital heart disease?

AIM

To determine the role of preoperative cranial ultrasound (cUS) in predicting neurodevelopmental outcome in infants undergoing bypass surgery for congenital heart disease (CHD).

METHOD

Prospective cohort study on 77 infants (44 males, 33 females) operated before 3 months of age (median age at surgery 10d [range 3-88d]) who received at least one preoperative cUS. Outcome at 1 year was assessed with a standardized neurological examination and the Bayley Scales of Infant Development II (mental developmental index [MDI]; psychomotor developmental index [PDI]).

RESULTS

Abnormalities on cUS were detected in 22 (29%) infants and consisted of diffuse brain oedema (n=12, 16%), periventricular white matter injury (n=5, 6%), ventricular dilatation (n=3, 4%), and intraventricular haemorrhage (IVH) (n=2, 3%). Infants undergoing balloon-atrial septostomy (BAS) had a higher rate of subsequent brain oedema than those without BAS (p=0.006). cUS abnormalities were not related to neurodevelopmental outcome.

INTERPRETATION

Preoperative cUS findings in infants undergoing bypass surgery for CHD occur rather frequently, consisting of mild lesions such as brain oedema or white matter changes. These findings, however, do not correlate with early neurodevelopmental outcome.

Congenital cardiac anomalies and white matter injury

Cardiac abnormalities are the most common birth defects. Derangement of circulatory flow affects many vital organs; without proper supply of oxygenated blood, the brain is particularly vulnerable. Although surgical interventions have greatly reduced mortality rates, patients often suffer an array of neurological deficits throughout life. Neuroimaging provides a macroscopic assessment of brain injury and has shown that white matter (WM) is at risk. Oligodendrocytes and myelinated axons have been identified as major targets of WM injury, but still little is known about how congenital heart anomalies affect the brain at the cellular level. Further integration of animal model studies and clinical research will define novel therapeutic targets and new standards of care to prevent developmental delay associated with cardiac abnormalities.

The association between brain injury, perioperative anesthetic exposure, and 12-month neurodevelopmental outcomes after neonatal cardiac surgery: a retrospective cohort study

BACKGROUND

Adverse neurodevelopmental outcomes are observed in up to 50% of infants after complex cardiac surgery. We sought to determine the association of perioperative anesthetic exposure with neurodevelopmental outcomes at age 12 months in neonates undergoing complex cardiac surgery and to determine the effect of brain injury determined by magnetic resonance imaging (MRI).

METHODS

Retrospective cohort study of neonates undergoing complex cardiac surgery who had preoperative and 7-day postoperative brain MRI and 12-month neurodevelopmental testing with Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). Doses of volatile anesthetics (VAA), benzodiazepines, and opioids were determined during the first 12 months of life.

RESULTS

From a database of 97 infants, 59 met inclusion criteria. Mean ± sd composite standard scores were as follows: cognitive = 102.1 ± 13.3, language = 87.8 ± 12.5, and motor = 89.6 ± 14.1. After forward stepwise multivariable analysis, new postoperative MRI injury (P = 0.039) and higher VAA exposure (P = 0.028) were associated with lower cognitive scores. ICU length of stay (independent of brain injury) was associated with lower performance on all categories of the Bayley-III (P < 0.02).

CONCLUSIONS

After adjustment for multiple relevant covariates, we demonstrated an association between VAA exposure, brain injury, ICU length of stay, and lower neurodevelopmental outcome scores at 12 months of age. These findings support the need for further studies to identify potential modifiable factors in the perioperative care of neonates with CHD to improve neurodevelopmental outcomes.

Focal necrosis and disturbed myelination in the white matter of newborn infants: a tale of too much or too little oxygen

White matter disease in preterm infants comes along with focal destructions or with diffuse myelination disturbance. Recent experimental work with transgenic mice paves the way for a unifying molecular model for both types of brain injury, placing oxygen sensing by oligodendrocyte precursor cells (OPCs) at the center stage. Mice genetically altered to mimic high local oxygen tension in oligodendroglia lineage cells (via deletion of hypoxia-inducible factor, HIF) develop white matter disease resembling cystic periventricular leukomalacia within the first 7 days of life. Mice in which local hypoxia is mimicked in oligodendroglial cells (via genetic inhibition of HIF decay) display arrested OPC maturation and subsequent hypomyelination, reminiscent of the diffuse white matter disease observed in preterm infants and infants with congenital heart disease. These recent experimental findings on oxygen sensing and myelination are awaiting integration into a clinical framework. Gene regulation in response to hyperoxia or hypoxia, rather than oxidative stress, may be an important mechanism underlying neonatal white matter disease.