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

Stroke in children with cardiac disease: report from the International Pediatric Stroke Study Group Symposium

BACKGROUND

Cardiac disease is a leading cause of stroke in children, yet limited data support the current stroke prevention and treatment recommendations. A multidisciplinary panel of clinicians was convened in February 2014 by the International Pediatric Stroke Study group to identify knowledge gaps and prioritize clinical research efforts for children with cardiac disease and stroke.

RESULTS

Significant knowledge gaps exist, including a lack of data on stroke incidence, predictors, primary and secondary stroke prevention, hyperacute treatment, and outcome in children with cardiac disease. Commonly used diagnostic techniques including brain computed tomography and ultrasound have low rates of stroke detection, and diagnosis is frequently delayed. The challenges of research studies in this population include epidemiologic barriers to research such as small patient numbers, heterogeneity of cardiac disease, and coexistence of multiple risk factors. Based on stroke burden and study feasibility, studies involving mechanical circulatory support, single ventricle patients, early stroke detection strategies, and understanding secondary stroke risk factors and prevention are the highest research priorities over the next 5-10 years. The development of large-scale multicenter and multispecialty collaborative research is a critical next step. The designation of centers of expertise will assist in clinical care and research.

CONCLUSIONS

There is an urgent need for additional research to improve the quality of evidence in guideline recommendations for cardiogenic stroke in children. Although significant barriers to clinical research exist, multicenter and multispecialty collaboration is an important step toward advancing clinical care and research for children with cardiac disease and stroke.

Vasoactive Inotrope Score as a tool for clinical care in children post cardiac surgery

BACKGROUND

Neonates and infants undergoing heart surgery on cardiopulmonary bypass (CPB) are at high risk for significant post-operative morbidity and mortality. Hence, there is a need to identify and quantify clinical factors during the early post-operative period that are indicative of short-term as well as long-term outcomes. Multiple inotrope scores have been used in practice to quantify the amount of cardiovascular support received by neonates.

AIMS

The goal of this study was to determine the association between inotropic/vasoactive support and clinical outcomes in children after open cardiac surgery.

MATERIALS AND METHODS

This is a retrospective analysis of the 208 patients who underwent cardiac surgery for congenital heart disease at a tertiary pediatric cardiac surgery Intensive Care Unit (ICU) from January 2012 to March 2013. Multiple demographic, intra-operative and post-operative variables were recorded, including the Vasoactive Inotrope Score (VIS).

RESULTS

A total of 208 patients underwent cardiac surgery for congenital heart disease in the study period. The mean age and weight in the study were 66.94 months and 16.31 kg, respectively. Statistically significant associations were found in the various variables and VIS, including infancy, weight < 10 kg, CPB time, pump failure and post-operative variables like sepsis, hematological complications, hepatic dysfunction, acute kidney injury during admission, mortality, prolonged ventilator requirement, CPB time (in min) and hospital stay.

CONCLUSIONS

Inotrope score and its adaptations are an excellent tool to measure illness severity, deciding interventions and during parental counseling in the pediatric cardiac surgery ICUs.

Glial fibrillary acidic protein in children with congenital heart disease undergoing cardiopulmonary bypass

OBJECTIVE

To determine whether blood levels of the brain-specific biomarker glial fibrillary acidic protein rise during cardiopulmonary bypass for repair of congenital heart disease.

METHODS

This is a prospective observational pilot study to characterise the blood levels of glial fibrillary acidic protein during bypass. Children <21 years of age undergoing bypass for congenital heart disease at Johns Hopkins Hospital and Texas Children's Hospital were enrolled. Blood samples were collected during four phases: pre-bypass, cooling, re-warming, and post-bypass.

RESULTS

A total of 85 patients were enrolled between October, 2010 and May, 2011. The median age was 0.73 years (range 0.01-17). The median weight was 7.14 kilograms (range 2.2-86.5). Single ventricle anatomy was present in 18 patients (22%). Median glial fibrillary acidic protein values by phase were: pre-bypass: 0 ng/ml (range 0-0.35); cooling: 0.039 (0-0.68); re-warming: 0.165 (0-2.29); and post-bypass: 0.112 (0-0.97). There were significant elevations from pre-bypass to all subsequent stages, with the greatest increase during re-warming (p = 0.0001). Maximal levels were significantly related to younger age (p = 0.03), bypass time (p = 0.03), cross-clamp time (p = 0.047), and temperature nadir (0.04). Peak levels did not vary significantly in those with single ventricle anatomy versus two ventricle repairs.

CONCLUSION

There are significant increases in glial fibrillary acidic protein levels in children undergoing cardiopulmonary bypass for repair of congenital heart disease. The highest values were seen during the re-warming phase. Elevations are significantly associated with younger age, bypass and cross-clamp times, and temperature nadir. Owing to the fact that glial fibrillary acidic protein is the most brain-specific biomarker identified to date, it may act as a rapid diagnostic marker of brain injury during cardiac surgery.

Evidence of second-trimester changes in head biometry and brain perfusion in fetuses with congenital heart disease

OBJECTIVES

To evaluate the associations between congenital heart disease (CHD) and head biometry and cerebrovascular blood flow dynamics at the time of diagnosis of CHD in the second trimester of pregnancy.

METHODS

This was a study of 95 consecutive fetuses diagnosed with CHD. At the time of diagnosis, fetal biometry was performed and brain perfusion was assessed by middle cerebral artery pulsatility index (MCA-PI), cerebroplacental ratio (CPR) and fractional moving blood volume (FMBV). The results were compared with those of 95 normal fetuses matched for gestational age.

RESULTS

Median gestational age at diagnosis was 22 + 3 (range, 20 + 0 to 23 + 5) weeks. Fetuses with CHD showed significantly lower MCA-PI and CPR Z-scores (-0.23 vs 0.34 and -0.37 vs 0.30, respectively; both P < 0.001) and higher FMBV Z-scores (2.35 vs 0.15; P < 0.001). FMBV > 95(th) percentile was observed in 81.1% of cases as compared with 10.5% in controls (P < 0.001). Moreover, cases showed significantly smaller biparietal diameter (BPD) and head circumference (HC) Z-scores (-1.61 vs -0.43 and -0.89 vs 0.09, respectively; both P < 0.001), with a higher proportion of BPD and HC measurements below the 5(th) percentile compared with controls (51.6% vs 13.7% and 26.3% vs 4.2%, respectively; both P < 0.001). These findings were more pronounced in those cases with types of CHD associated with compromised oxygenated blood delivery to the brain, such as left outflow tract obstruction and transposition of the great arteries.

CONCLUSIONS

A high proportion of fetuses with CHD have a smaller head and increased brain perfusion already in the second trimester, suggesting an early onset of the mechanisms leading to poorer neurodevelopment later in life.

Time to surgery and preoperative cerebral hemodynamics predict postoperative white matter injury in neonates with hypoplastic left heart syndrome

OBJECTIVE

Hypoxic-ischemic white mater brain injury commonly occurs in neonates with hypoplastic left heart syndrome (HLHS). Approximately one half of HLHS survivors will exhibit neurobehavioral symptoms believed to be associated with this injury, although the exact timing of the injury is unknown.

METHODS

Neonates with HLHS were recruited for pre- and postoperative monitoring of cerebral oxygen saturation, cerebral oxygen extraction fraction, and cerebral blood flow using 2 noninvasive optical-based techniques: diffuse optical spectroscopy and diffuse correlation spectroscopy. Anatomic magnetic resonance imaging was performed before and approximately 1 week after surgery to quantify the extent and timing of the acquired white matter injury. The risk factors for developing new or worsened white matter injury were assessed using uni- and multivariate logistic regression.

RESULTS

A total of 37 neonates with HLHS were studied. On univariate analysis, neonates who developed a large volume of new, or worsened, postoperative white matter injury had a significantly longer time to surgery (P=.0003). In a multivariate model, a longer time between birth and surgery, delayed sternal closure, and greater preoperative cerebral blood flow were predictors of postoperative white matter injury. Additionally, a longer time to surgery and greater preoperative cerebral blood flow on the morning of surgery correlated with lower cerebral oxygen saturation (P=.03 and P=.05, respectively) and greater oxygen extraction fraction (P=.05 for both).

CONCLUSIONS

A longer time to surgery was associated with new postoperative white matter injury in otherwise healthy neonates with HLHS. The results suggest that earlier Norwood palliation might decrease the likelihood of acquiring postoperative white matter injury.

Brain volume and neurobehavior in newborns with complex congenital heart defects

OBJECTIVE

To investigate the relationship between tissue-specific alterations in brain volume and neurobehavioral status in newborns with complex congenital heart defects preoperatively.

STUDY DESIGN

Three-dimensional volumetric magnetic resonance imaging was used to calculate tissue-specific brain volumes and a standardized neurobehavioral assessment was performed to assess neurobehavioral status in 35 full-term newborns admitted to the hospital before cardiopulmonary bypass surgery. Multiple linear regression models were performed to evaluate relationships between neurobehavioral status and brain volumes.

RESULTS

Reduced subcortical gray matter (SCGM) volume and increased cerebrospinal fluid (CSF) volume were associated with poor behavioral state regulation (SCGM, P = .04; CSF, P = .007) and poor visual orienting (CSF, P = .003). In cyanotic newborns, reduced SCGM was associated with higher overall abnormal scores on the assessment (P = .001) and poor behavioral state regulation (P = .04), and increased CSF volume was associated with poor behavioral state regulation (P = .02), and poor visual orienting (P = .02). Conversely, acyanotic newborns showed associations between reduced cerebellar volume and poor behavioral state regulation (P = .03).

CONCLUSION

Abnormal neurobehavior is associated with impaired volumetric brain growth before open heart surgery in infants with complex congenital heart defects. This study highlights a need for routine preoperative screening and early intervention to improve neurodevelopmental outcomes.

Clinical examination and pulse oximetry as screening for congenital heart disease in low-risk newborn

OBJECTIVE

To assess sensitivity, specificity, positive predictive value and negative predictive value of the cardiovascular physical examination (CPE) and of pulse oximetry in screening for congenital heart diseases (CHD) in asymptomatic newborn when prenatal ultrasound evaluation is negative for structural cardiac abnormalities.

METHODS

In this observational cohort study, 5750 asymptomatic newborns, admitted to nursery in a period of 2 years, underwent to CPE and determination of arterial oxygen saturation by pulse oxymetry between 48th and 72nd h of life.

RESULTS

Two hundred and ninty-eight newborns presented a suspected CPE; in 70% of cases, we found a transitional alteration and in only 17% of cases, the echocardiography examination performed for suspected CPE were completely negative. Three newborns were positive to pulse oximetry screening test but negative at CPE. After discharge, one case of critical CHD was diagnosed.

CONCLUSIONS

An accurate CPE performed by trained and experienced pediatricians is indicative of important cardiac structural alteration in more than 25%. The association of CPE and pulse oximetry allows to further improve the diagnostic accuracy.

Changes in cerebral oxygen saturation correlate with S100B in infants undergoing cardiac surgery with cardiopulmonary bypass

OBJECTIVES

The relationship of cerebral saturation measured by near-infrared spectroscopy with serum biomarker of brain injury S100B was investigated in infants undergoing cardiac surgery with cardiopulmonary bypass.

DESIGN

Prospective cohort study.

SETTING

Single-center children's hospital.

PATIENTS

Forty infants between 1 and 12 months old weighing greater than or equal to 4 kg with congenital heart disease undergoing cardiac surgery with cardiopulmonary bypass were enrolled.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Serum S100B was measured at eight time points over 72 hours using enzyme-linked immunosorbent assay. Physiologic data including arterial, cerebral, and somatic regional oxygen saturations measured by near-infrared spectroscopy were synchronously recorded at 1-minute intervals from anesthesia induction through 72 postoperative hours. The arterial-cerebral oxygen saturation difference was calculated as the difference between arterial saturation and cerebral regional saturation. Thirty-eight patients, 5.4 ± 2.5 months old, were included in the analysis; two were excluded due to the use of postoperative extracorporeal membrane oxygenation. Seventeen patients (44.7%) had preoperative cyanosis. S100B increased during cardiopulmonary bypass in all patients, from a median preoperative baseline of mean ± SE: 0.055 ± 0.038 to a peak of 0.610 ± 0.038 ng/mL, p less than 0.0001. Patients without preoperative cyanosis had a higher S100B peak at the end of cardiopulmonary bypass. Although the absolute cerebral regional saturation on cardiopulmonary bypass was not associated with S100B elevation, patients who had arterial-cerebral oxygen saturation difference greater than 50 at any time during cardiopulmonary bypass had a higher S100B peak (mean ± SE: 1.053 ± 0.080 vs 0.504 ± 0.039 ng/mL; p < 0.0001).

CONCLUSIONS

A wide cerebral arteriovenous difference measured by near-infrared spectroscopy during cardiopulmonary bypass is associated with increased serum S100B in the perioperative period and may be a modifiable risk factor for neurological injury.

Academic proficiency in children after early congenital heart disease surgery

Children with early surgery for congenital heart disease (CHD) are known to have impaired neurodevelopment; their performance on school-age achievement tests and their need for special education remains largely unexplored. The study aimed to determine predictors of academic achievement at school age and placement in special education services among early CHD surgery survivors. Children with CHD surgery at <1 year of age from January 1, 1998 to December 31, 2003, at the Arkansas Children's Hospital were identified. Out-of-state births and infants with known genetic and/or neurologic conditions were excluded. Infants were matched to an Arkansas Department of Education database containing standardized assessments at early school age and special-education codes. Predictors for achieving proficiency in literacy and mathematics and the receipt of special education were determined. Two hundred fifty-six children who attended Arkansas public schools and who had surgery as infants were included; 77.7 % had either school-age achievement-test scores or special-education codes of mental retardation or multiple disabilities. Scores on achievement tests for these children were 7-13 % lower than those of Arkansas students (p < 0.01). They had an eightfold increase in receipt of special education due to multiple disabilities [odds ratio (OR) 10.66, 95 % confidence interval (CI) 4.23-22.35] or mental retardation (OR 4.96, 95 % CI 2.6-8.64). Surgery after the neonatal period was associated with decreased literacy proficiency, and cardiopulmonary bypass during the first surgery was associated with decreased mathematics proficiency. Children who had early CHD surgery were less proficient on standardized school assessments, and many received special education. This is concerning because achievement-test scores at school age are "real-world" predictors of long-term outcomes.

Brain volumetric, regional cortical thickness and radiographic findings in adults with cyanotic congenital heart disease

Background

Chronic cyanosis in adults with congenital heart disease (CHD) may cause structural brain changes that could contribute to impaired neurological functioning. The extent of these changes has not been adequately characterized.

Hypothesis

We hypothesized that adults with cyanotic CHD would have widespread changes including abnormal brain volumetric measures, decreased cortical thickness and an increased burden of small and large vessel ischemic changes.

Methods

Ten adults with chronic cyanosis from CHD (40 ± 4 years) and mean oxygen saturations of 82 ± 2% were investigated using quantitative MRI. Hematological and biochemical parameters were also assessed. All subjects were free from major physical or intellectual impairment. Brain volumetric results were compared with randomly selected age- and sex-matched controls from our database of normal subjects.

Results

Five of 10 cyanotic subjects had cortical lacunar infarcts. The white matter (WM) hyperintensity burden was also abnormally high (Scheltens Scale was 8 ± 2). Quantitative MRI revealed evidence of extensive generalized WM and gray matter (GM) volumetric loss; global GM volume was reduced in cyanosed subjects (630 ± 16 vs. 696 ± 14 mL in controls, p = 0.01) as was global WM volume (471 ± 10 vs. 564 ± 18 mL, p = 0.003). Ventricular cerebrospinal fluid volume was increased (35 ± 10 vs. 26 ± 5 mL, p = 0.002). There were widespread regions of local cortical thickness reduction observed across the brain. These changes included bilateral thickness reductions in the frontal lobe including the dorsolateral prefrontal cortex and precentral gyrus, the posterior parietal lobe and the middle temporal gyrus. Sub-cortical volume changes were observed in the caudate, putamen and in the thalamus (p ≤ 0.005 for all regions). Cortical GM volume negatively correlated with brain natriuretic peptide (R = − 0.89, p = 0.009), high sensitivity C-reactive protein (R = − 0.964, p < 0.0001) and asymmetric dimethylarginine (R = − 0.75, p = 0.026) but not with oxygen saturations, packed cell volume or viscosity.

Conclusions

We present the first comprehensive analysis of brain structure in adults with chronic neurocyanosis due to congenital heart disease. We demonstrate clear evidence for marked macro- and microvascular injury. Cyanotic patients show global evidence for reduced brain volume as well as specific foci of cortical thickness reduction. The GM volume loss correlated with hsCRP, BNP and ADMA suggesting that inflammation, neurohormonal activation and endothelial dysfunction may have important roles in its pathogenesis.

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A high burden of cerebral small and large vessel ischemic injury.

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Extensive white and gray matter (GM) volumetric loss.

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Regions of bilateral local cortical thickness reduction within the frontal, parietal and temporal lobes.

Multi-tiered analysis of brain injury in neonates with congenital heart disease

Early brain injury occurs in newborns with congenital heart disease (CHD) placing them at risk for impaired neurodevelopmental outcomes. Predictors for preoperative brain injury have not been well described in CHD newborns. This study aimed to analyze, retrospectively, brain magnetic resonance imaging (MRI) in a heterogeneous group of newborns who had CHD surgery during the first month of life using a detailed qualitative CHD MRI Injury Score, quantitative imaging assessments (regional apparent diffusion coefficient [ADC] values and brain volumes), and clinical characteristics. Seventy-three newborns who had CHD surgery at 8 ± 5 (mean ± SD) days of life and preoperative brain MRI were included; 38 also had postoperative MRI. Thirty-four (34 of 73, 47 %) had at least one type of preoperative brain injury, and 28 of 38 (74 %) had postoperative brain injury. The 5-min APGAR score was negatively associated with preoperative injury, but there was no difference between CHD types. Infants with intraparenchymal hemorrhage, deep gray matter injury, and/or watershed infarcts had the highest CHD MRI Injury Scores. ADC values and brain volumes were not different in infants with different CHD types or in those with and without brain injury. In a mixed group of CHD newborns, brain injury was found preoperatively on MRI in almost 50 %, and there were no significant baseline characteristic differences to predict this early brain injury except 5-min APGAR score. We conclude that all infants, regardless of CHD type, who require early surgery should be evaluated with MRI because they are all at high risk for brain injury.

Abnormal cerebral microstructure in premature neonates with congenital heart disease

BACKGROUND AND PURPOSE

Abnormal cerebral microstructure has been documented in term neonates with congenital heart disease, portending risk for injury and poor neurodevelopmental outcome. Our hypothesis was that preterm neonates with congenital heart disease would demonstrate diffuse cerebral microstructural abnormalities when compared with critically ill neonates without congenital heart disease. A secondary aim was to identify any association between microstructural abnormalities, white matter injury (eg, punctate white matter lesions), and other clinical variables, including heart lesions.

MATERIALS AND METHODS

With the use of tract-based spatial statistics, an unbiased, voxelwise method for analyzing diffusion tensor imaging data, we compared 21 preterm neonates with congenital heart disease with 2 cohorts of neonates without congenital heart disease: 28 term and 27 preterm neonates, identified from the same neonatal intensive care unit.

RESULTS

Compared with term neonates without congenital heart disease, preterm neonates with congenital heart disease had microstructural abnormalities in widespread regions of the central white matter. However, 42% of the preterm neonates with congenital heart disease had punctate white matter lesions. When neonates with punctate white matter lesions were excluded, microstructural abnormalities remained only in the splenium. Preterm neonates with congenital heart disease had similar microstructure to preterm neonates without congenital heart disease.

CONCLUSIONS

Diffuse microstructural abnormalities were observed in preterm neonates with congenital heart disease, strongly associated with punctate white matter lesions. Independently, regional vulnerability of the splenium, a structure associated with visual spatial function, was observed in all preterm neonates with congenital heart disease.

Neurodevelopmental outcome in children with congenital heart disease

Children with congenital heart disease (CHD) have multiple factors contributing toward their risk of later neurodevelopmental difficulties. With earlier diagnosis and improved survival rates, the management of CHD now includes the recognition of neurodevelopmental risks and optimisation of neurodevelopmental outcomes is emphasised. Neuroimaging studies have shown early differences in brain development for children with CHD, who then are vulnerable to additional brain injury in the perinatal period. For some children, complications and co-morbidities may further increase the risk of brain injury. Synthesis of multiple factors is necessary to estimate neurodevelopmental prognosis for an individual child. Long-term neurodevelopmental follow-up of children with CHD is warranted for early identification of and intervention for difficulties.

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

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

Attention deficit/hyperactivity disorder after neonatal surgery: review of the pathophysiology and risk factors

There are many factors that influence the long-term neurological outcomes in children following cardiac surgery. Because there is also complex interaction between these many factors, it is difficult to assess which are primary and modifiable and which can be used to make improvements in outcomes. As survival after complex neonatal heart surgery has increased, the number of children with long-term neurological deficits is becoming more evident and this affects quality of life for children and their families.

One area of long-term assessment is the incidence of attention deficit/hyperactivity disorder (ADHD). The incidence rate for ADHD following pediatric cardiac surgery is significantly higher than the normal rate for children of the same age. Because this is a measureable long-term outcome, it can be used to evaluate methods for cerebral protection during surgery as well as the timing of surgical procedures to maximize cerebral oxygen levels.

This paper will review the pathophysiological basis for ADHD in this population, based on the similarities between neonatal cardiac surgical patients and pre-term infants. Both populations have an increased risk for ADHD and the etiology and pathological changes in pre-term infants have been widely investigated over the past 25 years. The rate of ADHD in this population is a window into the effects of these pathological changes on long-term outcomes.

Reducing the incidence of ADHD in the future in this population should be a primary goal in developing and assessing new cerebral protective strategies during cardiac surgery.

Risk factors for preoperative periventricular leukomalacia in term neonates with hypoplastic left heart syndrome are patient related

BACKGROUND

Preoperative brain injury is common in neonates with complex congenital heart disease. Increasing evidence suggests a complex interaction of prenatal and postnatal risk factors for development of brain white matter injury, called periventricular leukomalacia (PVL), in neonates with complex congenital heart disease. To date, there remains a limited understanding of the risk factors contributing to preoperative PVL in hypoplastic left heart syndrome (HLHS).

METHODS

Neonates with HLHS or HLHS variants from 3 prospective magnetic resonance imaging studies (2003-2010) were selected for this cohort. Preoperative brain magnetic resonance imaging was performed the morning of the surgery. Stepwise multilogistic regression of patient characteristics, mode of delivery (cesarean section vs vaginal), time of diagnosis (prenatal vs postnatal), HLHS subtypes, brain total maturation score, time to surgery, individual averaged daily preoperative blood gases, and complete blood cell count values was used to determine significant associations.

RESULTS

A total of 57 neonates with HLHS were born at 38.7 ± 2.3 weeks; 86% (49/57) had a prenatal diagnosis, with 31% (18/57) delivered by cesarean section. HLHS with aortic atresia (AA) was common in this cohort, 71% (41/57). Preoperative PVL was identified in 19% (11/57). Male patients with AA (P = .004) were at higher risk for PVL. Lower total brain maturation score was also identified as a strong predictor for preoperative PVL (P = .005).

CONCLUSIONS

In neonates with HLHS, nonmodifiable patient-related factors, including male sex with AA (lack of antegrade blood flow) and lower total brain maturation score, placed neonates at the greatest risk for preoperative white matter injury.

Multifocal haemorrhagic brain damage following hypoxia and blood pressure lability: case report and rat model

AIMS

Haemorrhagic brain damage is frequently encountered as a complication of premature birth. Much less frequently, multifocal petechial haemorrhage is identified in asphyxiated term newborns. Our goal was to develop an experimental rat model to reproduce this pattern of brain damage.

METHODS

Neonatal rat pups were exposed to a 24-h period of 10% or 8% hypoxia followed by a single dose of phenylephrine. Acute and subacute changes, as well as long-term outcomes, were investigated by histology, brain magnetic resonance imaging and behavioural assessment. Immunostaining for vascular endothelial growth factor and caveolin-1 was performed in the rat brains as well as in a 17-day human case.

RESULTS

Small foci of haemorrhage were identified in almost all regions of the rat brain subjected to hypoxia plus phenylephrine, but not hypoxia alone. Exposure to 8% hypoxia was associated with more haemorrhagic foci than 10% hypoxia. With rare exceptions, the blood deposits were too small to be detected by magnetic resonance imaging. Altered immunohistochemical detection of vascular endothelial growth factor and caveolin-1 in the child and the rat model suggests a role for blood-brain barrier compromise. There were no clear behavioural changes and no residual morphological abnormalities in the 78-day follow-up of the rats.

CONCLUSIONS

We conclude that transient hypoxia, in a dose-dependent manner, can weaken the vasculature and predispose to brain haemorrhage in the situation of labile blood pressure. Persistent hypoxia is likely to be important in the genesis of permanent severe brain damage.

Abnormal interhemispheric connectivity in neonates with D-transposition of the great arteries undergoing cardiopulmonary bypass surgery

BACKGROUND AND PURPOSE

Neonates with severe CHD require CPB within the first days of life. White matter injury can occur before surgery, and this may impair the long-term neurodevelopmental and psychosocial outcome. The purpose of this study was to assess the microstructural development of the CC in infants with CHD before and after CPB for transposition of the great arteries.

MATERIALS AND METHODS

Fifteen patients with CHD and 11 age-matched HC were recruited. We separately quantified the parallel (E1) and perpendicular (E23) diffusions, the ADC, and FA of the genu of the CC and splenium of the CC before and after surgery.

RESULTS

In presurgical measures of the genu of the CC, higher E23 (P = .018), higher ADC (P = .026), and lower FA (P = .033) values were measured compared with those in HC. In the postsurgery scans, the genu of the CC had higher E23 (P = .013), higher ADC (P = .012), and lower FA (P = .033) values compared with those in HC. There was no significant difference in any DTI indices between the pre- and postsurgical groups.

CONCLUSIONS

We report abnormal microstructural development in the genu of the CC of infants with d-TGA before and after CPB. High E23, high ADC, and low FA values in the genu of the CC may be explained by abnormal axonal pruning, thinner myelin sheaths, smaller axonal diameters, or more oligodendrocytes. It appears that the genu of the CC is more vulnerable than the splenium of the CC in patients with CHD and may serve as a biomarker to identify infants at highest risk for adverse neurodevelopmental outcome.

Adolescents with D-transposition of the great arteries repaired in early infancy demonstrate reduced white matter microstructure associated with clinical risk factors

OBJECTIVE

Our objective was to use diffusion tensor imaging (DTI) to compare white matter microstructure in adolescents with D-transposition of the great arteries (D-TGA) who underwent the arterial switch operation in early infancy with typically developing control adolescents. We also examined correlates between patient demographic and medical risk factors and white matter as assessed by regional fractional anisotropy (FA) values.

METHODS

We used with magnetic resonance imaging (MRI) to study 49 adolescents with D-TGA and 29 control adolescents. MRI data, including whole brain DTI and conventional anatomic MRI, were acquired from each subject. Each subject's data were analyzed using random effects analysis to evaluate regional white matter differences in FA between D-TGA and control adolescents.

RESULTS

While multifocal punctate MRI hypointensities on T1-weighted (T1W) imaging suggestive of mineralization were found, other evidence of gross white matter injury was absent. Eighteen discrete regions of significantly reduced FA in D-TGA adolescents compared with controls were observed in deep white matter of cerebral hemispheres, cerebellum, and midbrain. Among D-TGA adolescents, lower FA correlated with younger gestational age, shorter duration of intraoperative cooling, higher intraoperative minimum tympanic temperature, longer intensive care unit stay after repair, and greater total number of open cardiac operations.

CONCLUSIONS

Despite scant white matter injury evident on conventional brain MRI, adolescents with D-TGA repaired in infancy demonstrate significant white matter FA reduction that may relate to their reported neurocognitive deficits. Among adolescents with D-TGA, FA values are associated with patient and perioperative factors, some of which are modifiable.

In favor of the Hybrid Stage 1 as the initial palliation for hypoplastic left heart syndrome

There are many reasons to consider using the Hybrid Stage 1 procedure as the initial palliation for hypoplastic left heart syndrome. It allows all options for treatment, including a delayed traditional approach, as well as a platform to evolve our overall approach to this challenging heart defect.

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

BACKGROUND

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

METHODS AND RESULTS

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

CONCLUSIONS

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

Comparative analysis of cerebrovascular resistance in fetuses with single-ventricle congenital heart disease

OBJECTIVE

We sought to determine whether the presence or absence of aortic obstruction impacts cerebrovascular resistance in fetuses with single-ventricle (SV) congenital heart disease (CHD).

METHODS

Pulsatility indices (PIs) were recorded for the middle cerebral artery (MCA) and the umbilical artery (UA) from 18 to 40 weeks' gestation in 59 fetuses (163 examinations) with SV-CHD with unobstructed aortic flow, yet decreased pulmonary flow, in 72 fetuses (170 examinations) with obstructed aortic flow and hypoplastic left heart syndrome (HLHS) and in 92 normal fetuses (92 examinations). The cerebral-to-placental resistance (CPR) was calculated as the MCA-PI/UA-PI. Z-scores were generated for the MCA-PI and the UA-PI in order to make comparisons independent of gestational age. Statistical analyses were performed using one-way ANOVA with post-hoc testing. Trends in these variables over the course of gestation were assessed using linear regression and univariate ANOVA.

RESULTS

The MCA-PI and the CPR were significantly lower in SV fetuses with aortic obstruction compared with SV fetuses with pulmonary obstruction and with normal fetuses. Moreover, the MCA-PI decreased significantly for SV fetuses with aortic obstruction over the course of gestation. In contrast, the MCA-PI was higher over the course of gestation in SV fetuses with pulmonary obstruction compared with normal fetuses.

CONCLUSION

In fetuses with SV-CHD, cerebrovascular resistance varies substantially between fetuses with and without aortic obstruction. Compared with normal fetuses, cerebrovascular resistance is decreased in SV fetuses with aortic obstruction, yet increased in SV fetuses with pulmonary obstruction. In fetuses with SV physiology, inherent differences in cerebral blood flow may underlie postnatal neurodevelopmental outcomes.

Short-term neurodevelopmental outcomes in neonates with congenital heart disease: the era of newer surgical strategies

OBJECTIVE

The objective of this study was to determine neurodevelopmental outcomes up to 30 months of age in a cohort of neonates requiring surgical intervention without circulatory arrest for congenital heart disease and to correlate these outcomes with characteristics detected prior to hospital discharge.

DESIGN AND SETTING

An observational cohort of surviving neonates who underwent surgical intervention without circulatory arrest for congenital heart disease between 2002 and 2003 was studied at a single tertiary care institution.

PATIENTS

Thirty-five patients were followed from 4 to 6 months of age until 24-30 months of age.

OUTCOME MEASURES

Neuromotor abnormalities, use of special services, and degree of developmental delay at set intervals between 4 and 30 months of age were retrospectively obtained from clinical reports. The relationship between these outcomes and clinical characteristics prior to hospital discharge was analyzed.

RESULTS

Those with neuromotor abnormalities prior to discharge were likely to have persistent abnormalities in muscle strength, tone, and symmetry until 4-6 months of age, odds ratio 6 (1.3-29). By 24-30 months of age, motor abnormalities or developmental delay occurred in 10 of 20 infants (50%), but were no longer significantly associated with predischarge findings.

CONCLUSIONS

Infants undergoing surgical intervention for congenital heart disease are at risk for neurodevelopmental abnormalities, which may not become apparent until months after hospital discharge. Early impairment may also resolve over time. Close developmental follow-up in this high-risk cohort of patients is warranted.

Balloon atrial septostomy and pre-operative brain injury in neonates with transposition of the great arteries: a systematic review and a meta-analysis

OBJECTIVE

To perform a systematic review and a meta-analysis of the effects of balloon atrial septostomy on peri-operative brain injury in neonates with transposition of the great arteries.

DATA SOURCE

We conduct a systematic review of the literature to identify all observational studies that included neonates born with transposition of the great arteries who had peri-operative evidence of brain injury.

STUDY SELECTION AND DATA EXTRACTION

The search strategy produced three prospective and two retrospective cohort studies investigating the association between balloon atrial septostomy and brain injury totalling 10,108 patients. In two studies, the outcome was represented by the presence of a coded diagnosis of a clinically evident stroke at discharge, whereas in three studies the outcome was represented by the finding of pre-operative brain injury identified by magnetic resonance scans.

DATA SYNTHESIS

The overall brain injury rate for neonates who underwent balloon atrial septostomy versus control patients was 60 of 2273 (2.6%) versus 45 of 7835 (0.5%; pooled odds ratio, 1.90; 95% confidence intervals, 0.93-3.89; p = 0.08). A subgroup analysis of the three studies that used pre-operative brain injury as the primary outcome found no significant association between balloon atrial septostomy and brain injury (pooled odds ratio, 2.70; 95% confidence intervals, 0.64-11.33; p = 0.17). Balloon atrial septostomy frequency was 22.4% (2273 of 10,108), with reported rates ranging from 20% to 75%.

CONCLUSION

Our analysis shows that balloon atrial septostomy is not associated with increased odds for peri-operative brain injury. Balloon atrial septostomy should still be used for those patients with significant hypoxaemia, haemodynamic instability, or both.

Regional alterations in cerebral growth exist preoperatively in infants with congenital heart disease

OBJECTIVES

Magnetic resonance imaging has been used to define the neurologic abnormalities in infants with congenital heart disease (CHD), including preoperative injury and delayed brain maturation. The present study used qualitative scoring, cerebral biometry, and diffusion imaging to characterize the preoperative brain abnormalities in infants with CHD, including the identification of regions of greater vulnerability.

METHODS

A total of 67 infants with CHD had preoperative magnetic resonance imaging scans available for analysis of brain injury using qualitative scoring and brain development using qualitative scoring, metrics, and diffusion imaging.

RESULTS

Qualitative abnormalities were common, with 42% of infants having preoperative focal white matter lesions. Infants with CHD had smaller brain measures in the frontal lobe, parietal lobe, cerebellum, and brainstem (P < .001), with the frontal lobe and brainstem displaying the greatest alterations (P < .001). A smaller brain size in the frontal and parietal lobes correlated with delayed white matter microstructure reflected by diffusion imaging.

CONCLUSIONS

Infants with CHD commonly display brain injury and delayed brain development. Regional alterations in brain size are present, with the frontal lobe and brainstem demonstrating the greatest alterations. This might reflect a combination of developmental vulnerability and regional differences in cerebral circulation.

Neurocognitive development and behavioral outcome of 2-year-old children with univentricular heart

Recent advances in the treatment of children with severe congenital heart defects, such as hypoplastic left heart syndrome (HLHS) and other forms of univentricular heart (UVH), have significantly improved their survival rates. However, these children are at risk for various neurodevelopmental deficits. The aim of the present study was to assess cognitive development, expressive language, and behavior in 30-month-old children with univentricular heart. The participants were 22 children with HLHS, 14 with UVH, and 41 healthy control subjects. The Bayley Scales of Infant Development II, MacArthur Communicative Development Inventories, and Child Behavior Checklist were used for assessments. The results revealed that children with HLHS exhibited a significantly lower mean mental development index, more delays in expressive language functions, and more behavioral problems than did the control children. Two children with HLHS (9%) had mental development indexes below 50, indicating significantly delayed performance. The children with UVH differed from the control children with respect to their lower mean mental development index. These findings suggest that at the age of 30 months, neurodevelopmental deficits are especially prevalent in children with HLHS. Thus, early developmental screening, intervention, and neuropsychological follow-up until school age is recommended particularly for the children with HLHS.

Impact of congenital heart disease on fetal brain development and injury

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

SUMMARY

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

Infection and white matter injury in infants with congenital cardiac disease

More than 60% of newborns with severe congenital cardiac disease develop perioperative brain injuries. Known risk factors include: pre-operative hypoxemia, cardiopulmonary bypass characteristics, and post-operative hypotension. Infection is an established risk factor for white matter injury in premature newborns. In this study, we examined term infants with congenital cardiac disease requiring surgical repair to determine whether infection is associated with white matter injury. Acquired infection was specified by site - bloodstream, pneumonia, or surgical site infection - according to strict definitions. Infection was present in 23 of 127 infants. Pre- and post-operative imaging was evaluated for acquired injury by a paediatric neuroradiologist. Overall, there was no difference in newly acquired post-operative white matter injury in infants with infection (30%), compared to those without (31%). When stratified by anatomy, infants with transposition of the great arteries, and bloodstream infection had an estimated doubling of risk of white matter injury that was not significant, whereas those with single ventricle anatomy had no apparent added risk. When considering only infants without stroke, the estimated association was higher, and became significant after adjusting for duration of inotrope therapy. In this study, nosocomial infection was not associated with white matter injury. Nonetheless, when controlling for risk factors, there was an association between bloodstream infection and white matter injury in selected sub-populations. Infection prevention may have the potential to mitigate long-term neurologic impairment as a consequence of white matter injury, which underscores the importance of attention to infection control for these patients.

Should what we know about neurobehavioral development, complex congenital heart disease, and brain maturation affect the timing of corrective cardiac surgery?

Despite remarkable improvements in perioperative care, adverse neurobehavioral outcomes following neonatal and infant cardiac surgery are commonplace and are associated with substantial morbidity. It is becoming increasingly clear that complex congenital heart disease is associated with both abnormalities in neuroanatomic development and a delay in fetal brain maturation. Substantial cerebral ischemic/hypoxic injury has been detected in neonates with complex congenital heart disease both prior to and following corrective cardiac surgery. The brain of the neonate with complex congenital heart disease appears to be uniquely vulnerable to the types of ischemic/hypoxic injury associated with perioperative care. It remains to be determined whether delaying surgical correction to allow for brain maturation will be associated with improvements in neurobehavioral outcomes.

Abnormal brain structure and function in newborns with complex congenital heart defects before open heart surgery: a review of the evidence

Newborns with complex congenital heart defects are at high risk for developing neurological abnormalities. It is important to understand the timing, progression, and extent of these abnormalities to better elucidate their potential impact on neurodevelopment, and their implications for early screening and intervention. This review synthesizes the recent literature describing neurological and neurobehavioral abnormalities observed in fetuses and newborns before cardiac surgery. A considerable proportion of newborns with complex congenital heart defects exhibit neurobehavioral and electrophysiological abnormalities preoperatively. Likewise, conventional neuroimaging studies reported that a high percentage of this population experienced brain injury. Advanced neuroimaging modalities indicated that fetuses showed delayed third trimester brain growth, and newborns showed impaired white matter maturation, reduced N-acetylaspartate, and increased lactate. These findings suggest a fetal or early postnatal onset of impaired brain growth and development. Consequently, reliable methods for early screening and subsequent developmental intervention must be implemented.

Structural brain lesions in adolescents with congenital heart disease

OBJECTIVES

To assess long-term neurodevelopmental outcome of adolescents with congenital heart disease after open-heart surgery and to evaluate whether deficits are associated with cerebral injury detectable on magnetic resonance imaging (MRI).

STUDY DESIGN

We conducted a cohort study with longitudinal follow-up of 53 adolescents (mean age, 13.7 years; range, 11.4 to 16.9 years) who had undergone open-heart surgery with full-flow cardiopulmonary bypass during childhood and compared them with 41 age-matched controls. Assessment included conventional MRI and neurodevelopmental testing.

RESULTS

MRI abnormalities were detected in 11 of the 53 patients (21%), comprising predominately white matter abnormalities and volume loss. Neurodevelopmental outcome was impaired in several domains, including neuromotor, intellectual, and executive functions, as well as visuomotor perception and integration. Adolescents with cerebral abnormalities had greater impairment in most neurodevelopmental domains compared with those without cerebral abnormalities.

CONCLUSIONS

Cerebral abnormalities can be detected in a significant proportion of adolescents with corrected congenital heart disease. These abnormalities are found predominately in the white matter and are apparently of hypoxic-ischemic origin, most likely acquired during the neonatal period.

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

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

Executive function and theory of mind in school-aged children after neonatal corrective cardiac surgery for transposition of the great arteries

AIM

cardiac malformations resulting in cyanosis, such as transposition of the great arteries (TGA), have been associated with neurodevelopmental dysfunction. The purpose of this study was to assess, for the first time, theory of mind (ToM), which is a key component of social cognition and executive functions in school-aged children with TGA.

METHOD

twenty-one children (14 males, seven females; mean age 7y 4mo; SD 3mo) who underwent neonatal open-heart surgery for TGA using full-flow cardiopulmonary bypass were compared with 21 typically developing age-matched children (12 males, nine females; mean age 7y 6mo; SD 3.8mo) using different neuropsychological measures specifically designed to assess executive function (cognitive and response inhibition, verbal and spatial working memory, and planning). They were also given two ToM tasks (first- and second-order false belief understanding).

RESULTS

general IQ was within the normal range in both the TGA group and the comparison group (mean IQ 113 [SD 9.3] and 118 [SD 10.1] respectively), but performance on all executive functions and on ToM (first and second level) was significantly lower in the TGA group (p values of 0.02, 0.01, and 0.004 respectively). A discriminant multivariate analysis provided evidence for cognitive and behavioural inhibition as well as performance on false belief tasks as being the most important contributors to the differentiation between the groups (p=0.03).

INTERPRETATION

children with TGA demonstrate great difficulties in exerting cognitive and behavioural inhibition. They also present specific deficits in false belief understanding, which were related to immature executive abilities.

Imaging and clinical characteristics of children with multiple foci of microsusceptibility changes in the brain on susceptibility-weighted MRI

BACKGROUND

Microsusceptibility changes in the brain are well known to correspond with microbleeds or micrometal fragments in adults, but this phenomenon has not been explored well in children.

OBJECTIVE

To assess imaging and clinical characteristics of children with multiple foci of microsusceptibility changes using susceptibility-weighted imaging (SWI).

MATERIALS AND METHODS

Between 2006 and 2008, 12 children with multiple foci of microsusceptibility on SWI without corresponding abnormal signal on conventional MRI were identified and were retrospectively assessed.

RESULTS

The locations of foci of microsusceptibility included the cerebral white matter, basal ganglia, brainstem and cerebellar white matter, without any clear systematic anatomic distribution. CT (n=5) showed no calcification at the locations corresponding to the microsusceptibility on SWI. Conventional MR imaging showed white matter volume loss (n=5), delayed myelination (n=2), acute infarction (n=1), chronic infarction (n=1), meningitis (n=1), slight signal abnormality in the white matter (n=1) and no abnormal findings (n=1). Follow-up SWI (n=3) showed no change of the microsusceptibility foci. Interestingly, all children had a history of heart surgery under extracorporeal circulation for congenital heart disease.

CONCLUSION

Multiple foci of microsusceptibility can be seen in the brain on SWI in children with congenital heart disease who underwent heart surgery with extracorporeal circulation.

Regional cortical volumes and congenital heart disease: a MRI study in 22q11.2 deletion syndrome

Children with congenital heart disease (CHD) who survive surgery often present impaired neurodevelopment and qualitative brain anomalies. However, the impact of CHD on total or regional brain volumes only received little attention. We address this question in a sample of patients with 22q11.2 deletion syndrome (22q11DS), a neurogenetic condition frequently associated with CHD. Sixty-one children, adolescents, and young adults with confirmed 22q11.2 deletion were included, as well as 80 healthy participants matched for age and gender. Subsequent subdivision of the patients group according to CHD yielded a subgroup of 27 patients with normal cardiac status and a subgroup of 26 patients who underwent cardiac surgery during their first years of life (eight patients with unclear status were excluded). Regional cortical volumes were extracted using an automated method and the association between regional cortical volumes, and CHD was examined within a three-condition fixed factor. Robust protection against type I error used Bonferroni correction. Smaller total cerebral volumes were observed in patients with CHD compared to both patients without CHD and controls. The pattern of bilateral regional reductions associated with CHD encompassed the superior parietal region, the precuneus, the fusiform gyrus, and the anterior cingulate cortex. Within patients, a significant reduction in the left parahippocampal, the right middle temporal, and the left superior frontal gyri was associated with CHD. The present results of global and regional volumetric reductions suggest a role for disturbed hemodynamic in the pathophysiology of brain alterations in patients with neurodevelopmental disease and cardiac malformations.

Relationship of intraoperative cerebral oxygen saturation to neurodevelopmental outcome and brain magnetic resonance imaging at 1 year of age in infants undergoing biventricular repair

BACKGROUND

Near-infrared spectroscopy monitoring of cerebral oxygen saturation (rSo(2)) has become routine in many centers, but no studies have reported the relationship of intraoperative near-infrared spectroscopy to long-term neurodevelopmental outcomes after cardiac surgery.

METHODS AND RESULTS

Of 104 infants undergoing biventricular repair without aortic arch reconstruction, 89 (86%) returned for neurodevelopmental testing at 1 year of age. The primary near-infrared spectroscopy variable was the integrated rSo(2) (area under the curve) for rSo(2) <or=45%; secondary variables were the average and minimum rSo(2) by perfusion phase and at specific time points. Psychomotor and mental development indexes of the Bayley scales, head circumference, neurological examination, and abnormalities on brain magnetic resonance imaging did not differ between subjects according to a threshold level for rSo(2) of 45%. Lower Psychomotor Development Index scores were modestly associated with lower average (r=0.23, P=0.03) and minimum (r=0.22, P=0.04) rSo(2) during the 60-minute period after cardiopulmonary bypass but not with other perfusion phases. Hemosiderin foci on brain magnetic resonance imaging were associated with lower average rSo(2) from postinduction to 60 minutes post cardiopulmonary bypass (71+/-10% versus 78+/-6%, P=0.01) and with lower average rSO(2) during the rewarming phase (72+/-12% versus 83+/-9%, P=.003) and during the 60-minute period following cardiopulmonary bypass (65+/-11% versus 75+/-10%, P=0.009). In regression analyses that adjusted for age <or=30 days, Psychomotor Development Index score (P=0.02) and brain hemosiderin (P=0.04) remained significantly associated with rSo(2) during the 60-minute period following cardiopulmonary bypass.

CONCLUSIONS

Perioperative periods of diminished cerebral oxygen delivery, as indicated by rSo(2), are associated with 1-year Psychomotor Development Index and brain magnetic resonance imaging abnormalities among infants undergoing reparative heart surgery. Clinical Trial Registration- URL: http://clinicaltrials.gov. Unique identifier: NCT00006183.