Preoperative cranial ultrasound findings in infants with major congenital heart disease

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

IMPACT

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

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

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

Neurological complications after pediatric cardiac surgery

Background

The number of pediatric patients who survive open-heart surgery has increased in recent years and the complications seen in this patient group continue to decrease with each technological advance, including new surgical and neuroprotective techniques and the improvement in surgeons' experience with this patient population. However, neurological complications, which are the most feared and difficult to manage, require long-term follow-up, and increase hospital costs remain a leading cause of mortality and morbidity in this cohort.

Results

We evaluated the neurological physical examination, cranial computed tomography (CT), and magnetic resonance (MRI) records of 162 pediatric patients with neurological symptoms lasting more than 24 h after undergoing heart surgery in our clinic between June 2012 and May 2020. The patients' ages ranged from 0 to 205 months, with a mean of 60.59 ± 46.44 months.Of the 3849 pediatric cardiac surgery patients we screened, 162 had neurological complications in the early period (the first 10 days after surgery). The incidence was calculated as 4.2%; 69 patients (42.6%) experienced seizures, 17 (10.5%) experienced confusion, 39 (24.1%) had stupor, and 37 (22.8%) had hemiparesis. Of the patients who developed neurological complications, 54 (33.3%) died. Patients with neurological complications were divided into 3 groups: strokes (n = 90), intracranial bleeding (n = 37), and no radiological results (n = 35). Thirty-four patients (37.8%) in the stroke group died, as did 15 (40%) in the bleeding group, and 5 (14.3%) in the no radiological results group.

Conclusions

Studies on neurological complications after pediatric heart surgery in the literature are currently insufficient. We think that this study will contribute to a more detailed discussion of the issue. Responses to neurological events and treatment in the pediatric group may differ compared to the adult age group. Primary prevention methods should be the main approach in combating neurological complications; their formation mechanisms should be carefully monitored and preventive treatment strategies should be developed.

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.

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.

Abnormal fetal cerebral and vascular development in hypoplastic left heart syndrome

Objective

To assess the cerebral and vascular development in fetuses with hypoplastic left heart syndrome (HLHS).

Methods

Pregnant women carrying fetuses diagnosed with HLHS who decided to interrupt their pregnancies were included in our study. Aortic size and blood flow were assessed based from fetal echocardiography. Immunohistochemical staining was performed in brain sections obtained from pathology in fetuses with HLHS and control fetuses without heart disease.

Results

Twenty‐seven midgestation fetal HLHS were included (gestational age, 23.3 ± 3.4 weeks). Head circumference z scores were lower in HLHS fetuses. Middle cerebral artery pulsatility index, a measure of cerebrovascular resistance, was inversely correlated with the ascending aortic z score (P < 0.05). Fetuses with HLHS had lower capillary density in the germinal matrix and their capillaries were larger compared with control fetuses with (P < 0.05). The expression of neuronal differentiation marker, FGFR1, and oligodendrocyte precursor, O4, were lower in HLHS brains compared with controls (P < 0.05).

Conclusion

Our study identified abnormalities of vascular flow and structural brain abnormalities in fetal HLHS associated with impaired neuronal and oligodendrocyte differentiation, as well as cerebral growth impairment, early in gestation. These findings may be related in part to early vascular abnormalities.

What's already known about this topic?

Structural brain abnormalities and abnormalities in neurodevelopment have been reported in HLHS.

What does this study add?

Our study describes abnormal vascular development that may account for abnormal neuronal and white matter differentiation in the developing fetus with HLHS.

Advanced diffusion imaging for assessing normal white matter development in neonates and characterizing aberrant development in congenital heart disease

Background

Elucidating developmental trajectories of white matter (WM) microstructure is critically important for understanding normal development and regional vulnerabilities in several brain disorders. Diffusion Weighted Imaging (DWI) is currently the method of choice for in-vivo white matter assessment. A majority of neonatal studies use the standard Diffusion Tensor Imaging (DTI) model although more advanced models such as the Neurite Orientation Dispersion and Density Imaging (NODDI) model and the Gaussian Mixture Model (GMM) have been used in adult population. In this study, we compare the ability of these three diffusion models to detect regional white matter maturation in typically developing control (TDC) neonates and regional abnormalities in neonates with congenital heart disease (CHD).

Methods

Multiple b-value diffusion Magnetic Resonance Imaging (dMRI) data were acquired from TDC neonates (N = 16) at 38 to 47 gestational weeks (GW) and CHD neonates (N = 19) aged 37 weeks to 41 weeks. Measures calculated from the diffusion signal included not only Mean Diffusivity (MD) and Fractional Anisotropy (FA) derived from the standard DTI model, but also three advanced diffusion measures, namely, the fiber Orientation Dispersion Index (ODI), the isotropic volume fraction (Viso), and the intracellular volume fraction (Vic) derived from the NODDI model. Further, we used two novel measures from a non-parametric GMM, namely the Return-to-Origin Probability (RTOP) and Return-to-Axis Probability (RTAP), which are sensitive to axonal/cellular volume and density respectively. Using atlas-based registration, 22 white matter regions (6 projection, 4 association, and 1 callosal pathways bilaterally in each hemisphere) were selected and the mean value of all 7 measures were calculated in each region. These values were used as dependent variables, with GW as the independent variable in a linear regression model. Finally, we compared CHD and TDC groups on these measures in each ROI after removing age-related trends from both the groups.

Results

Linear analysis in the TDC population revealed significant correlations with GW (age) in 12 projection pathways for MD, Vic, RTAP, and 11 pathways for RTOP. Several association pathways were also significantly correlated with GW for MD, Vic, RTAP, and RTOP. The right callosal pathway was significantly correlated with GW for Vic. Consistent with the pathophysiology of altered development in CHD, diffusion measures demonstrated differences in the association pathways involved in language systems, namely the Uncinate Fasciculus (UF), the Inferior Fronto-occipital Fasciculus (IFOF), and the Superior Longitudinal Fasciculus (SLF). Overall, the group comparison between CHD and TDC revealed lower FA, Vic, RTAP, and RTOP for CHD bilaterally in the a) UF, b) Corpus Callosum (CC), and c) Superior Fronto-Occipital Fasciculus (SFOF). Moreover, FA was lower for CHD in the a) left SLF, b) bilateral Anterior Corona Radiata (ACR) and left Retrolenticular part of the Internal Capsule (RIC). Vic was also lower for CHD in the left Posterior Limb of the Internal Capsule (PLIC). ODI was higher for CHD in the left CC. RTAP was lower for CHD in the left IFOF, while RTOP was lower in CHD in the: a) left ACR, b) left IFOF and c) right Anterior Limb of the Internal Capsule (ALIC).

Conclusion

In this study, all three methods revealed the expected changes in the WM regions during the early postnatal weeks; however, GMM outperformed DTI and NODDI as it showed significantly larger effect sizes while detecting differences between the TDC and CHD neonates. Future studies based on a larger sample are needed to confirm these results and to explore clinical correlates.

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.

Functional, quality of life, and neurodevelopmental outcomes after congenital cardiac surgery

Throughout the past few decades, advances in cardiology, neonatal intensive care, and surgical techniques have resulted in a growing cohort of thriving school-aged children with previously lethal complex congenital heart diseases. While survival has increased, there remains significant morbidity following repair including neurodevelopmental sequelae. Compared to children with a structurally normal heart, these infants and children have a higher frequency of abnormalities in tone, feeding, and delayed developmental milestones, as well as challenges with speech and learning disabilities, while a higher proportion of adolescents suffer from problems with processing speed, executive function, and a unique set of medical hardships related to exercise intolerance and obesity, medication burden, and mental health comorbidities. Innovative perioperative techniques and early psychosocial intervention in these young survivors has shown that despite the obstacles, the majority of these children can grow to have fulfilling lives with intelligence and social skills in the normal range. Additionally, a comprehensive medical home aids in optimizing the quality of life for these children and their families.

Reduced fetal brain fissures depth in fetuses with congenital heart diseases

OBJECTIVE

To screen and detect cortex gyration in fetuses with congenital heart disease (CHD) using Ultrasonography (US) during routine obstetric scans.

METHODS

The depth of the Sylvian fissure (SF), parieto-occipital fissure (POF), and calcarine (CF) fissure were prospectively serially measured and compared in 45 fetuses with CHD and 45 normal fetuses. Cardiac hemodynamic parameters, including aortic valve diameter (AV), pulmonary valve diameter (PV), velocity time integral of the aortic valve (VTIav), and velocity time integral of the pulmonary valve (VTIpv), were recorded. Correlations between the fissure depths and the prenatal cardiac hemodynamic parameters and postnatal neurodevelopmental scores were assessed.

RESULTS

SF, POF, and CF were decreased in CHD fetuses compared with the controls in late of pregnancy (P < 0.01). The diagnostic category was independently associated with smaller fissure depths in fetuses with CHD (adjusted R²  = 0.472 for SF, 0.465 for POF, and 0.425 for CF). Correlations were observed between small fissure depths and decreased left heart hemodynamic parameters (AV and VTIav) in fetuses with CHD. The SF depth was positively correlated with the neurodevelopmental scores (P < 0.01).

CONCLUSIONS

US can be used to screen for abnormal fetal brain cortex development during routine obstetric scans and to evaluate the maturation progress during close follow-up. © 2016 John Wiley & Sons, Ltd.

Mid-gestation brain Doppler and head biometry in fetuses with congenital heart disease predict abnormal brain development at birth

OBJECTIVES

Fetuses with congenital heart disease (CHD) show evidence of abnormal brain development before birth, which is thought to contribute to adverse neurodevelopment during childhood. Our aim was to evaluate whether brain development in late pregnancy can be predicted by fetal brain Doppler, head biometry and the clinical form of CHD at the time of diagnosis.

METHODS

This was a prospective cohort study including 58 fetuses with CHD, diagnosed at 20-24 weeks' gestation, and 58 normal control fetuses. At the time of diagnosis, we recorded fetal head circumference (HC), biparietal diameter, middle cerebral artery pulsatility index (MCA-PI), cerebroplacental ratio (CPR) and brain perfusion by fractional moving blood volume. We classified cases into one of two clinical types defined by the expected levels (high or low) of placental (well-oxygenated) blood perfusion, according to the anatomical defect. All fetuses underwent subsequent 3T-magnetic resonance imaging (MRI) at 36-38 weeks' gestation.

RESULTS

Abnormal prenatal brain development was defined by a composite score including any of the following findings on MRI: total brain volume <  10(th) centile, parietoccipital or cingulate fissure depth <  10(th) centile or abnormal metabolic profile in the frontal lobe. Logistic regression analysis demonstrated that MCA-PI (odds ratio (OR), 12.7; P = 0.01), CPR (OR, 8.7; P = 0.02) and HC (OR, 6.2; P = 0.02) were independent predictors of abnormal neurodevelopment; however, the clinical type of CHD was not.

CONCLUSIONS

Fetal brain Doppler and head biometry at the time of CHD diagnosis are independent predictors of abnormal brain development at birth, and could be used in future algorithms to improve counseling and targeted interventions. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

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.

Imaging patterns of sonographic lenticulostriate vasculopathy and correlation with clinical and neurodevelopmental outcome

PURPOSE

To evaluate the relationship between the imaging patterns of lenticulostriate vasculopathy (LSV) and clinical outcomes.

METHODS

We performed cranial sonography (US) in 110 neonates and evaluated the patterns of visible lenticulostriate vessels with three grades: 0: no vessel seen; 1 (low grade): one or two thin branches seen; and 2 (high grade): more than three prominent branches seen. Color Doppler US was performed on these vessels to evaluate the presence of flow. Associated underlying diseases and the presence of neurodevelopmental delay on follow-up were reviewed retrospectively.

RESULTS

There were 51 neonates with associated underlying diseases, including congenital heart diseases (CHD) (n = 34) and neonatal hypoxia (n = 13). Sonographic LSV was detected in 29.1% cases (22 low- and 10 high-grade cases). Doppler flow was not detected in three patients with CHD (p = 0.028). CHD (odds ratio [OR], 25.73; p < 0.001), neonatal hypoxia (OR, 7.00; p = 0.020), two underlying diseases (OR, 73.232; p < 0.001), high-grade LSV (OR, 16.29; p = 0.005), and absent color Doppler flow (OR, 40.80; p = 0.046) were significantly associated with neurodevelopmental delay in univariate analysis. In multivariate analysis, underlying diseases and absent color Doppler flow were associated with neurodevelopmental delay. Both high LSV grade (area under the receiver operating characteristic curves of 0.901; 95% confidence interval, 0.823-0.979) and absent color Doppler flow (area under the receiver operating characteristic curves of 0.874; 95% confidence interval, 0.803-0.945) had a high predictive power for neurodevelopmental delay.

CONCLUSIONS

High-grade sonographic LSV and absent color Doppler flow on lenticulostriate vessels were significantly associated with neurodevelopmental delay.

Brain abnormalities and neurodevelopmental delay in congenital heart disease: systematic review and meta-analysis

OBJECTIVES

Studies have demonstrated an association between congenital heart disease (CHD) and neurodevelopmental delay. Neuroimaging studies have also demonstrated a high incidence of preoperative brain abnormalities. The aim of this study was to perform a systematic review to quantify the non-surgical risk of brain abnormalities and of neurodevelopmental delay in infants with CHD.

METHODS

MEDLINE, EMBASE and The Cochrane Library were searched electronically without language restrictions, utilizing combinations of the terms congenital heart, cardiac, neurologic, neurodevelopment, magnetic resonance imaging, ultrasound, neuroimaging, autopsy, preoperative and outcome. Reference lists of relevant articles and reviews were hand-searched for additional reports. Cohort and case-control studies were included. Studies reporting neurodevelopmental outcomes and/or brain lesions on neuroimaging in infants with CHD before heart surgery were included. Cases of chromosomal or genetic abnormalities, case reports and editorials were excluded. Between-study heterogeneity was assessed using the I(2) test.

RESULTS

The search yielded 9129 citations. Full text was retrieved for 119 and the following were included in the review: 13 studies (n = 425 cases) reporting on brain abnormalities either preoperatively or in those who did not undergo congenital cardiac surgery and nine (n = 512 cases) reporting preoperative data on neurodevelopmental assessment. The prevalence of brain lesions on neuroimaging was 34% (95% CI, 24-46; I(2) = 0%) in transposition of the great arteries, 49% (95% CI, 25-72; I(2) = 65%) in left-sided heart lesions and 46% (95% CI, 40-52; I(2) =18.1%) in mixed/unspecified cardiac lesions, while the prevalence of neurodevelopmental delay was 42% (95% CI, 34-51; I(2) = 68.9).

CONCLUSIONS

In the absence of chromosomal or genetic abnormalities, infants with CHD are at increased risk of brain lesions as revealed by neuroimaging and of neurodevelopmental delay. These findings are independent of the surgical risk, but it is unclear whether the time of onset is fetal or postnatal.

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

OBJECTIVE

The purpose of this study was to assess the utility of preoperative head ultrasound scan (HUS) in a cohort of newborns also undergoing preoperative MRI as part of a prospective research study of brain injury in infants having surgery for congenital heart disease (CHD).

METHODS

A total of 167 infants diagnosed with CHD were included in this 3-center study. None of the patients had clinical signs or symptoms of preoperative brain injury, and all patients received both HUS and brain MRI before undergoing surgical intervention. HUS and MRI results were reported by experienced neuroradiologists who were blinded to any specific clinical details of the study participants. The findings of the individual imaging modes were compared to evaluate for the presence of brain injury.

RESULTS

Preoperative brain injury was present on HUS in 5 infants (3%) and on MRI in 44 infants (26%) (P < .001). Four of the HUS showed intraventricular hemorrhage not seen on MRI, suggesting false-positive results, and the fifth showed periventricular leukomalacia. The predominant MRI abnormality was white matter injury (n = 32). Other findings included infarct (n = 16) and hemorrhage (n = 5).

CONCLUSIONS

Preoperative brain injury on MRI was present in 26% of infants with CHD, but only 3% had any evidence of brain injury on HUS. Among positive HUS, 80% were false-positive results. Our findings suggest that routine HUS is not indicated in asymptomatic term or near-term neonates undergoing surgery for CHD, and MRI may be a preferable tool when the assessment of these infants is warranted.

Structural congenital brain disease in congenital heart disease: results from a fetal MRI program

OBJECTIVE

To identify the type and incidence of fetal brain pathology in fetuses with a prenatal diagnosis of congenital heart disease (CHD).

PATIENTS AND METHODS

67 pregnant women underwent a fetal MR-examinations between 20 and 38 gestational weeks. MR was done on a 1.5 T superconducting system. The type of cardiac malformation was defined by fetal echocardiography. Fetuses with a chromosomal abnormality or an extracardiac anomaly were excluded.

RESULTS

Fetal MRI scans in the final study cohort (53 fetuses) yielded normal results in 32 fetuses and a brain abnormality in 21 fetuses. Congenital brain disease (CBD) was found in 39% of the final study cohort of fetuses with CHD. MRI findings were classified into malformations, acquired lesions and widening of the ventricles and/or outer CSF spaces (malformations: 7 fetuses, acquired lesions: 5 fetuses, changes in CSF spaces: 9 fetuses). Asymmetry of the ventricles was the most common finding in the CSF group.

CONCLUSIONS

Our data suggest that fetal MRI can be used to characterize structural CBD in CHD. Advanced MRI techniques such as diffusion tensor imaging and proton spectroscopy are tools that, in the future, will certainly shed light on the spectrum of structural and functional CBDs that are associated with CHD.

Critical congenital heart disease--utility of routine screening for chromosomal and other extracardiac malformations

Objective.  Infants with critical congenital heart disease (CHD) can have genetic and other extracardiac malformations, which add to the short- and long-term risk of morbidity and perhaps mortality. We sought to examine our center's practice of screening for extracardiac anomalies and to determine the yield of these tests among specific cardiac diagnostic categories. Design.  Retrospective review of infants admitted to the cardiac intensive care unit with a new diagnosis of CHD. Subjects were categorized into six groups: septal defects (SD), conotruncal defects (CTD), single-ventricle physiology (SV), left-sided obstructive lesions (LSO), right-sided obstructive lesions (RSO), and "other" (anomalous pulmonary venous return, Ebstein's anomaly). Screening modalities included genetic testing (karyotype and fluorescent in situ hybridization for 22q11.2 deletion), renal ultrasound (RUS), and head ultrasound (HUS). Results.  One hundred forty-one patients were identified. The incidence of cardiac anomalies was: CTD (36%), SD (18%), SV (18%), LSO (14%), RSO (3%), and "other" (8%). Overall 14% had an abnormal karyotype, 5% had a deletion for 22q11.2, 28% had an abnormal RUS and 22% had abnormal HUS. Patients in SD and SV had the highest incidence of abnormal karyotype (36% and 17%); 22q11.2 deletion was present only in CTD and LSO groups (9% and 7%, respectively); abnormal RUS and HUS were seen relatively uniformly in all categories. Premature infants had significantly higher incidence of renal 43% vs. 24%, and intracranial abnormalities 46% vs. 16%. Conclusion.  Infants with critical CHD and particularly premature infants have high incidence of genetic and other extracardiac anomalies. Universal screening for these abnormalities with ultrasonographic and genetic testing maybe warranted because early detection could impact short and long-term outcomes.

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.

State-of-the-art cranial sonography: Part 2, pitfalls and variants

OBJECTIVE

In the first part of this article, modern cranial sonography techniques and interpretation were discussed, emphasizing ways in which the application of modern imaging technology and techniques are able to enhance detection of pathologic abnormalities on cranial sonography.

CONCLUSION

In this part of the article, we will describe pitfalls and variants that may be confused with pathologic abnormalities. Emphasis will be placed on recognizing normal variations and distinguishing them from pathologic abnormalities that may require additional imaging or clinical follow-up.

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.

Amplitude integrated electroencephalographic activity in infants with congenital heart disease before surgery

BACKGROUND

Infants with congenital heart disease (CHD) are at risk for brain injury. An accurate tool to monitor brain function is amplitude integrated EEG (aEEG). It records both background patterns and electrographic seizure activity (EA).

AIMS

Our aim was to determine aEEG patterns in infants with CHD and to determine the differences between infants with a cyanotic or an acyanotic CHD.

STUDY DESIGN AND SUBJECTS

Sixty-two full term newborns had either a cyanotic CHD (transposition of the great arteries (n=24)) or an acyanotic CHD (hypoplastic left heart syndrome (n=26), critical aortic valve stenosis (n=1) or aortic coarctation (n=11)). The background patterns, sleep-wake cycling (SWC), and EA were assessed. The first 72h after starting prostaglandin E(1)-therapy were used for analysis.

RESULTS

The background patterns were mildly abnormal in 45% of the infants and severely abnormal at some point during the recording in 14% of the infants. We found no differences in background patterns between the two groups. EA was present in 12 (19%) infants. EA was more frequent in infants with acyanotic CHD (OR 9.4, 95% CI 1.1-78, p=0.039). SWC was equally frequent in infants with cyanotic and infants with acyanotic CHD. A severely abnormal aEEG and EA were associated with more profound acidosis.

CONCLUSIONS

Before surgery the majority of infants with a CHD had an abnormal aEEG. aEEG helped to identify EA and it was a useful tool to evaluate brain function prior to surgery in CHD.

Impact of congenital heart disease on brain development and neurodevelopmental outcome

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

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

CONTEXT

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Cerebral blood flow characteristics and biometry in fetuses undergoing prenatal intervention for aortic stenosis with evolving hypoplastic left heart syndrome

Children with hypoplastic left heart syndrome (HLHS) are at risk for neurodevelopmental dysfunction; prenatal factors may play a role in this predilection. Cerebral blood flow profiles are abnormal in fetuses with HLHS, raising the possibility that cerebral hemodynamics in utero may be related to neurodevelopmental abnormalities. Prenatal aortic valvuloplasty for fetal aortic stenosis with evolving HLHS is technically feasible and improves left heart hemodynamics. This study aimed to assess the effects of prenatal intervention on cerebral blood flow profiles and head circumference in fetuses with evolving HLHS. Seventy fetuses underwent prenatal aortic valvuloplasty for evolving HLHS (median 23 weeks gestation). Among 46 fetuses that had successful valvuloplasty and available data, middle cerebral artery (MCA) pulsatility (PI) and resistive (RI) indices were abnormal (Z-scores -1.7+/-1.1 and -2.2+/-1.4, p<0.001). Early post-valvuloplasty (n=33) and at late gestation follow-up (n=28), MCA PI and RI Z-scores remained low with no difference from pre- or early postintervention. Fetal head circumference was normal, as were umbilical artery PI and RI Z-scores. Cerebral blood flow characteristics are abnormal in mid-gestation fetuses with evolving HLHS, suggesting low cerebral vascular impedance. The mechanisms and significance of these abnormalities are unknown. Prenatal aortic valvuloplasty did not have a major impact on these indices. (E-mail: doff.mcelhinney@cardio.chboston.org).

Brain volume and metabolism in fetuses with congenital heart disease: evaluation with quantitative magnetic resonance imaging and spectroscopy

BACKGROUND

Adverse neurodevelopmental outcome is an important source of morbidity in children with congenital heart disease (CHD). A significant proportion of newborns with complex CHD have abnormalities of brain size, structure, or function, which suggests that antenatal factors may contribute to childhood neurodevelopmental morbidity.

METHODS AND RESULTS

Brain volume and metabolism were compared prospectively between 55 fetuses with CHD and 50 normal fetuses with the use of 3-dimensinal volumetric magnetic resonance imaging and proton magnetic resonance spectroscopy. Fetal intracranial cavity volume, cerebrospinal fluid volume, and total brain volume were measured by manual segmentation. Proton magnetic resonance spectroscopy was used to measure the cerebral N-acetyl aspartate: choline ratio (NAA:choline) and identify cerebral lactate. Complete fetal echocardiograms were performed. Gestational age at magnetic resonance imaging ranged from 25 1/7 to 37 1/7 weeks (median, 30 weeks). During the third trimester, there were progressive and significant declines in gestational age-adjusted total brain volume and intracranial cavity volume in CHD fetuses relative to controls. NAA:choline increased progressively over the third trimester in normal fetuses, but the rate of rise was significantly slower (P<0.001) in CHD fetuses. On multivariable analysis adjusted for gestational age and weight percentile, cardiac diagnosis and percentage of combined ventricular output through the aortic valve were independently associated with total brain volume. Independent predictors of lower NAA:choline included diagnosis, absence of antegrade aortic arch flow, and evidence of cerebral lactate (P<0.001).

CONCLUSIONS

Third-trimester fetuses with some forms of CHD have smaller gestational age- and weight-adjusted total brain volumes than normal fetuses and evidence of impaired neuroaxonal development and metabolism. Hemodynamic factors may play an important role in this abnormal development.

Disorders of the fetal circulation and the fetal brain

Even in the presence of normal placental function, cerebral oxygen-substrate supply may be disrupted by disturbances in the fetal circulation caused by anomalous cardiac development. The impact of these cardiac lesions is likely dictated primarily by the volume and oxygen-substrate composition of transverse aortic arch perfusion. Advances in fetal echocardiography, fetal Doppler ultrasound, and advanced fetal magnetic resonance imaging techniques capable of quantitative structural and functional measurements are providing major insights into the in vivo effects of these cardiac lesions on brain growth and development. The progress to date with the application of these techniques is reviewed in this article.

Role of amplitude-integrated electroencephalography in neonates with cardiovascular compromise

BACKGROUND

Neonates with congenital heart disease (CHD) and persistent pulmonary hypertension of the newborn (PPHN) represent conditions with increased risk of abnormal neurologic outcome. The role of aEEG in disorders where cerebral perfusion/oxygenation is affected by cardiac or pulmonary disease is unknown.

OBJECTIVE

The aim of the study was to characterize amplitude-integrated electroencephalography (aEEG) traces in nonasphyxiated neonates with cardiorespiratory compromise secondary to PPHN or CHD.

DESIGN/METHODS

Three hundred sixty-three aEEG records (June 2004-November 2006) were reviewed to identify neonates with a diagnosis of isolated CHD or PPHN. Clinical course, critical interventions, and neurodiagnostic investigation data were collected. The aEEG traces were reviewed by a single blinded expert and classified according to background activity (normal, moderate, or severely abnormal) and presence of seizures. The frequency of abnormal aEEG in both groups and its relationship to recognized markers of abnormal neurologic outcome (electrophysiology [EP] testing and neuroimaging [ultrasound (USS), computerized tomography, and magnetic resonance imaging] was studied.

RESULTS

Thirty neonates (PPHN [n = 20], CHD [n = 10]) were reviewed at a mean gestation of 39.2 +/- 1.1 weeks and weight of 3,375 +/- 565 g. Neonates with PPHN had lower Apgar scores at 1-minute (P = .02) and were significantly more likely to require inotropic support (P < .001), inhaled nitric oxide (P = .001), or surfactant (P = .01). An abnormal aEEG was found in 15 (50%) babies, but rates did not differ between CHD (n = 6) and PPHN (n = 9). The rates of abnormal composite neurologic outcome (2/3 of abnormal EP, neuroimaging, or neurologic examination) were significantly higher in neonates with abnormal aEEG. An abnormal magnetic resonance imaging was seen in 4 of 5 neonates with abnormal aEEG.

CONCLUSIONS

The risk of abnormal aEEG is high in sick neonates with PPHN or complex CHD. Prospective evaluation of the relationship between aEEG recordings in these disorders and acute cardiorespiratory physiology, comprehensive neuroimaging, and long-term patient outcomes is needed.

Preoperative brain injury in transposition of the great arteries is associated with oxygenation and time to surgery, not balloon atrial septostomy

BACKGROUND

Preoperative brain injury is an increasingly recognized phenomenon in neonates with complex congenital heart disease. Recently, reports have been published that associate preoperative brain injury in neonates with transposition of the great arteries with the performance of balloon atrial septostomy (BAS), a procedure that improves systemic oxygenation preoperatively. It is unclear whether BAS is the cause of brain injury or is a confounder, because neonates who require BAS are typically more hypoxemic. We sought to determine the relationship between preoperative brain injury in neonates with transposition of the great arteries and the performance of BAS. We hypothesized that brain injury results from hypoxic injury, not from the BAS itself.

METHODS AND RESULTS

Infants with transposition of the great arteries (n=26) were retrospectively included from a larger cohort of infants with congenital heart disease who underwent preoperative brain MRI as part of 2 separate prospective studies. Data collected included all preoperative pulse oximetry recordings, all values from preoperative arterial blood gas measurements, and BAS procedure data. MRI scans were performed on the day of surgery, before the surgical repair. Of the 26 neonates, 14 underwent BAS. No stroke was seen in the entire cohort, whereas 10 (38%) of 26 patients were found to have hypoxic brain injury in the form of periventricular leukomalacia. Periventricular leukomalacia was not associated with BAS; however, neonates with periventricular leukomalacia had lower preoperative oxygenation (P=0.026) and a longer time to surgery (P=0.028) than those without periventricular leukomalacia.

CONCLUSIONS

Preoperative brain injury in neonates with transposition of the great arteries is associated with hypoxemia and longer time to surgery. We found no association between BAS and brain injury.

Factors associated with adverse neurodevelopmental outcomes in infants with congenital heart disease

OBJECTIVE

To review reported neurodevelopmental outcome data for patients with congenital heart disease, identify risk factors for adverse neurodevelopmental sequelae and summarize potential neuromonitoring strategies that have been described.

METHODS

A Medline search was performed utilizing combinations of the keywords congenital heart, cardiac, neurologic, neurodevelopment, neuromonitoring, quality of life, and outcome. All prospective and longitudinal follow-up studies of patients with congenital heart disease were included. Additionally, studies that examined neuroimaging, neuromonitoring, and clinical factors in relation to outcome were examined. Case reports and editorials were excluded. Additional references were retrieved from selected articles if the abstract described an evaluation of neurodevelopmental outcomes and/or predictors of outcome in patients with congenital heart disease.

RESULTS

Overall, patients with CHD have increased rates of neurodevelopmental impairments, although intelligence appears to be in the normal range. Preoperative risk stratification, intraoperative techniques, postoperative care, and neuromonitoring strategies may all contribute to ultimate long-term neurodevelopmental outcomes in patients with CHD postsurgical repair.

CONCLUSIONS

As advances in the medical and surgical management improves survival in patients with CHD, increasing knowledge about neurodevelopmental outcomes and the factors that affect them will provide for strategies to optimize long-term outcome in this high-risk population.

Cerebral Oxygen Saturation Does Not Normalize Until After Stage 2 Single Ventricle Palliation

BACKGROUND

In an effort to optimize neurologic outcome, cerebral oxygen saturation (SCO2) is often measured intraoperatively and postoperatively. We hypothesized that SCO2 would be related to stage of palliation in children with single ventricle congenital heart disease.

METHODS

Cerebral oxygen saturation was continuously recorded intraoperatively in 34 infants and children undergoing palliative surgery on cardiopulmonary bypass for single ventricle congenital heart defects and in a control group of 12 neonates with ductus-dependent circulation undergoing complete repair. Saturations were correlated with the patient's stage and outcome.

RESULTS

Baseline SCO2 was 61% in single ventricle neonates (group P1, n = 10), 55% in neonates undergoing repair (group R), 42% in infants undergoing stage 2 palliation (group P2, n = 6), and 70% in children undergoing Fontan (group P3, n = 14). Baseline was lowest (41%) in infants undergoing interstage operations (group I, n = 4). After bypass, there was a significant improvement in SCO2 to 53% in group P2 infants (p = 0.04); there were no significant changes in the other groups. By the end of the operation, there was a significant decrease in SCO2 to 48% in group P1 (p = 0.001), with other groups unchanged from baseline. There were five perioperative deaths. Cerebral oxygen saturation at the conclusion of surgery was lower in children who died (38% versus 61%, p = 0.01).

CONCLUSIONS

In children with single ventricle physiology, SCO2 decreases after initial palliation, remains low before second-stage palliation, but is normal before and after the Fontan. This has implications for perioperative mortality, neurologic injury, and potentially for interim mortality. Low postoperative SCO2 predicts perioperative mortality.