Preoperative risk-of-death prediction model in heart surgery with deep hypothermic circulatory arrest in the neonate

Effect of congenital heart disease on 4-year neurodevelopment within multiple-gestation births

OBJECTIVES

We sought to assess the effect of congenital heart disease requiring infant surgery with cardiopulmonary bypass on neurodevelopmental outcomes and growth at 4 years of age, while matching for gestational age, socioeconomic status, maternal gestational conditions, home environment, and parental intelligence by studying multiple-gestation births.

METHODS

We performed within-family comparison of 14 multiple-gestation births in which 1 child had congenital heart disease requiring surgery with cardiopulmonary bypass at ≤6 months of age. Between 4 and 5 years of age, a comprehensive neurodevelopmental assessment was performed. Paired comparisons were conducted between siblings with and without heart defects using a series of nonparametric tests.

RESULTS

On average, the children qualified as late preterm (mean gestational age 35.4 ± 2.6 weeks). At an average age of 4.8 ± 0.1 years, children with congenital heart disease weighed less than their siblings (median weight for age z score -0.4 vs 0.1, P = .02) and had worse performance for cognition (median full-scale IQ 99 vs 109, P = .02) and fine motor skills (median Wide Range Assessment of Visual Motor Ability, Fine Motor score 94.5 vs 107.5, P < .01).

CONCLUSIONS

After controlling for socioeconomic status, home environment, parental intelligence, and gestational factors by using multiple-gestation births, congenital heart disease requiring surgery with cardiopulmonary bypass at ≤6 months of age is associated with lower weight, cognitive abilities and fine motor skills at 4 years of age.

Prevalence and pattern of executive dysfunction in school age children with congenital heart disease

OBJECTIVE

Executive function, a set of cognitive skills important to social and academic outcomes, is a specific area of cognitive weakness in children with congenital heart disease (CHD). We evaluated the prevalence and profile of executive dysfunction in a heterogeneous sample of school aged children with CHD, examined whether children with executive dysfunction are receiving school services and support, and identified risk factors for executive dysfunction at school age.

DESIGN

Ninety-one school aged patients completed questionnaires, including the Behavior Rating Inventory of Executive Function (BRIEF) and a medical history questionnaire. An age- and gender- matched control sample was drawn from a normative database.

RESULTS

Children with CHD had a higher rate of parent reported executive dysfunction (OR = 4.37, P < .0001), especially for working memory (OR = 8.22, P < .0001) and flexibility (OR = 8.05, P < .0001). Those with executive dysfunction were not more likely to be receiving school services (P > .05). Gender, premature birth (≤37 weeks), and CHD with aortic obstruction were predictive of executive dysfunction, especially for behavior regulation skills.

CONCLUSIONS

School aged children with CHD have an increased prevalence of executive dysfunction, especially problems with working memory and flexibility, and are underserved by the school system. The increased risk for executive dysfunction in those with CHD and prematurity or CHD with aortic obstruction suggests an etiology of delayed brain development in the fetal and neonatal periods, while male gender may increase susceptibility to brain injury. This study highlights the need for regular neurodevelopmental follow up in children with CHD, and a need to better understand mechanisms that contribute to adverse neurodevelopmental outcomes.

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

OBJECTIVES

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

STUDY DESIGN

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

RESULTS

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

CONCLUSION

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

Perioperative risk factors for impaired neurodevelopment after cardiac surgery in early infancy

OBJECTIVE

Historical cohort studies have reported adverse neurodevelopment following cardiac surgery during early infancy. Advances in surgical techniques and perioperative care have coincided with updating of neurodevelopmental assessment tools. We aimed to determine perioperative risk factors for impaired neurodevelopment at 2 years following surgery for congenital heart disease (CHD) in early infancy.

DESIGN AND PATIENTS

We undertook a prospective longitudinal study of 153 full-term infants undergoing surgery for CHD before 2 months of age. Infants were excluded if they had a genetic syndrome associated with neurodevelopmental impairment.

OUTCOME MEASURES

Predefined perioperative parameters were recorded and infants were classified according to cardiac anatomy. At 2 years, survivors were assessed using the Bayley Scales of Infant Development-III.

RESULTS

At 2 years, 130 children (98% of survivors) were assessed. Mean cognitive, language and motor scores were 93.4±13.6, 93.6±16.1 and 96.8±12.5 respectively (100±15 norm). Twenty (13%) died and 12 (9%) survivors had severe impairment (score <70), mostly language (8%). The lowest scores were in infants born with single ventricle physiology with obstruction to the pulmonary circulation who required a neonatal systemic-to-pulmonary artery shunt. Additional risk factors for impairment included reduced gestational age, postoperative elevation of lactate or S100B and repeat cardiac surgery.

CONCLUSIONS

In the modern era of infant cardiac surgery and perioperative care, children continue to demonstrate neurodevelopmental delays. The use of updated assessment tools has revealed early language dysfunction and relative sparing of motor function. Ongoing follow-up is critical in this high-risk population.

180 ml and less: Cardiopulmonary bypass techniques to minimize hemodilution for neonates and small infants

Objective. To determine the efficacy of decreasing cardiopulmonary bypass (CPB) prime volume for neonates and small infants by using low prime oxygenators, small diameter polyvinyl chloride (PVC) tubing and removing the arterial line filter (ALF) in an effort to reduce intraoperative exposure to multiple units of packed red blood cells (PRBC). Methods. Two retrospective database studies comparing neonatal CPB prime volume were undertaken: Study 1 — A CPB circuit consisting of a 1/8 inch arterial line, a 3/16 inch venous line and a low prime oxygenator with 172 ml total circuit prime ( n = 74) was compared to a circuit with a 3/16 inch arterial line, a 1/4 inch venous line and a higher prime oxygenator with a 350 ml total circuit prime ( n = 74). Study 2 — The 172 ml circuit ( n = 389) was compared to a circuit that included an ALF and had a total circuit prime volume of 218 ml ( n = 389). Results. Study 1— of the 74 neonates and small infants whose CPB prime volume was 350 ml, 19 were exposed to two or more intraoperative exogenous PRBC units while only 3 neonates and small infants in the 172 ml prime group ( n = 74) received two or more units ( p = 0.0002). Study 2 — of the 389 neonates and small infants where an ALF was used (prime volume 218 ml), 54 were exposed to two or more exogenous PRBC units while only 36 of the 389 patients where an ALF was not used (prime volume 172 ml) received two or more units of intraoperative PRBCs ( p = 0.0436). Conclusion. Decreasing the neonatal and small infant extracorporeal circuit prime volume by as little as 46 ml resulted in significantly fewer multiple exposures to exogenous PRBC units. Perfusion (2007) 22, 327—331.

Evaluating the Quality of Trials of Hypothermic Circulatory Arrest Aortic Surgery

The quality of level 1 evidence in reports on deep hypothermic circulatory arrest was assessed, and the confounding factors in surgical management and study design that can prevent meta-analysis formulation were determined. A systematic search of the literature was conducted using categorized nomenclature for randomized controlled trials in adult patients undergoing deep hypothermic circulatory arrest in the last 40 years. Twelve randomized controlled trials (2.3%) were found among 504 publications on deep hypothermic circulatory arrest listed on Medline from 1960; only 4 of them related to adults. One adequately powered study demonstrated reduced blood loss in deep hypothermic circulatory arrest using aprotinin. Three studies comparing retrograde and antegrade perfusion were underpowered. The median CONSORT score was 14 (range, 13–15). There were no consistent measures of similar outcomes (neuropsychometric, neurocognitive). No explanation was provided for the difference in reported ranges of neurological deficits in nonrandomized (5%–70%) and randomized (3%–9%) studies. Existing studies of deep hypothermic circulatory arrest are insufficient and inconsistent in the outcome measured, which explains the lack of a meta-analysis. Neurological injury remains high, and an appropriately powered study of interventions that can optimize cerebral perfusion is necessary.

Relationship between Social-Emotional and Neurodevelopment of 2-Year-Old Children with Congenital Heart Disease

OBJECTIVE

The purpose of this study was to describe social-emotional outcomes and the relationship with neurodevelopmental outcomes in a cohort of 2-year-old children who underwent surgery for congenital heart disease (CHD) in infancy, and explore the relationship between the outcomes and parental and surgical factors.

DESIGN

A two-center prospective cross-sectional cohort study.

PATIENTS

A cohort of 105 2-year-olds who underwent surgery in infancy for severe CHD MEASURES: Social-emotional and neurodevelopment was evaluated with the Infant and Toddler Social and Emotional Assessment tool (ITSEA), and the Bayley Scales of Infant Toddler Development, Third Edition.

RESULTS

Neurodevelopment was delayed in the CHD cohort with significantly worse results compared to published Australian-based norms in all domains (P < .001) and in the Cognitive (P < .001) and Language (P < .001) domains with respect to the reported American norms. Social-emotional outcome was similar to Australian norms in all domains but better than the American based norms in the Internalizing domain (P < .05). Higher maternal education was associated to better neurodevelopmental outcome in all domains and better scores in the internalizing and externalizing domains of the ITSEA. There was a moderate correlation (r = 0.43, P < .001) between Language and social-emotional competence. Motor development was influenced by the need for a significant cardiac reoperation.

CONCLUSIONS

The influences of social factors may be underestimated in the outcome of children with CHD. Language development in those with CHD may be improved with intervention targeting social-emotional competence; further research is needed in this area.

Risk Factors for Abnormal Developmental Trajectories in Young Children With Congenital Heart Disease

BACKGROUND

Children with congenital heart disease are at risk for developmental delay. This study sought to identify early risk factors for abnormal developmental trajectories in children with congenital heart disease.

METHODS AND RESULTS

Children with congenital heart disease at high risk for developmental delay, without known genetic abnormality, and with ≥3 assessments by the use of the Bayley Scales of Infant and Toddler Development, Third Edition, were studied. Logistic regression was used to assess the impact of patient and clinical factors on cognitive, language, and motor score trajectories; classified as: average or improved if all scores were ≥85 (<1 standard deviation below the mean) or increased to ≥85 and never decreased; or abnormal if all scores were <85, fell to <85 and never improved, or fluctuated above and below 85. Data on 131 children with 527 Bayley Scales of Infant and Toddler Development, Third Edition assessments were analyzed. Subject age was 5.5 to 37.4 months. Overall, 56% had cognitive, language, and motor development in the average range. Delays occurred in single domains in 23%. Multiple domains were delayed in 21%. More cardiac surgeries, longer hospital stay, poorer linear growth, and tube feeding were associated with worse outcomes in all domains (P<0.05). In the multivariable model, the need for tube feeding was a risk factor for having an abnormal developmental trajectory (odds ratio, 5.1-7.9). Minority race and lack of private insurance had significant relationships with individual domains.

CONCLUSIONS

Longitudinal developmental surveillance identified early factors that can help quantify the risk of developmental delay over time. Strategies to improve modifiable factors and early therapeutic intervention can be targeted to children at highest risk.

Burden of potentially pathologic copy number variants is higher in children with isolated congenital heart disease and significantly impairs covariate-adjusted transplant-free survival

OBJECTIVES

Copy number variants (CNVs) are duplications or deletions of genomic regions. Large CNVs are potentially pathogenic and are overrepresented in children with congenital heart disease (CHD). We sought to determine the frequency of large CNVs in children with isolated CHD, and to evaluate the relationship of these potentially pathogenic CNVs with transplant-free survival.

METHODS

These cases are derived from a prospective cohort of patients with nonsyndromic CHD (n = 422) identified before first surgery. Healthy pediatric controls (n = 500) were obtained from the electronic Medical Records and Genetic Epidemiology Network, and CNV frequency was contrasted for CHD cases and controls. CNVs were determined algorithmically; subsequently screened for >95% overlap between 2 methods, size (>300 kb), quality score, overlap with a gene, and novelty (absent from databases of known, benign CNVs); and separately validated by quantitative polymerase chain reaction. Survival likelihoods for cases were calculated using Cox proportional hazards modeling to evaluate the joint effect of CNV burden and known confounders on transplant-free survival.

RESULTS

Children with nonsyndromic CHD had a higher burden of potentially pathogenic CNVs compared with pediatric controls (12.1% vs 5.0%; P = .00016). Presence of a CNV was associated with significantly decreased transplant-free survival after surgery (hazard ratio, 3.42; 95% confidence interval, 1.66-7.09; P = .00090) with confounder adjustment.

CONCLUSIONS

We confirm that children with isolated CHD have a greater burden of rare/large CNVs. We report a novel finding that these CNVs are associated with an adjusted 2.55-fold increased risk of death or transplant. These data suggest that CNV burden is an important modifier of survival after surgery for CHD.

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.

Neurodevelopmental outcomes after cardiac surgery in infancy

BACKGROUND

Neurodevelopmental disability is the most common complication for survivors of surgery for congenital heart disease (CHD).

METHODS

We analyzed individual participant data from studies of children evaluated with the Bayley Scales of Infant Development, second edition, after cardiac surgery between 1996 and 2009. The primary outcome was Psychomotor Development Index (PDI), and the secondary outcome was Mental Development Index (MDI).

RESULTS

Among 1770 subjects from 22 institutions, assessed at age 14.5 ± 3.7 months, PDIs and MDIs (77.6 ± 18.8 and 88.2 ± 16.7, respectively) were lower than normative means (each P < .001). Later calendar year of birth was associated with an increased proportion of high-risk infants (complexity of CHD and prevalence of genetic/extracardiac anomalies). After adjustment for center and type of CHD, later year of birth was not significantly associated with better PDI or MDI. Risk factors for lower PDI were lower birth weight, white race, and presence of a genetic/extracardiac anomaly (all P ≤ .01). After adjustment for these factors, PDIs improved over time (0.39 points/year, 95% confidence interval 0.01 to 0.78; P = .045). Risk factors for lower MDI were lower birth weight, male gender, less maternal education, and presence of a genetic/extracardiac anomaly (all P < .001). After adjustment for these factors, MDIs improved over time (0.38 points/year, 95% confidence interval 0.05 to 0.71; P = .02).

CONCLUSIONS

Early neurodevelopmental outcomes for survivors of cardiac surgery in infancy have improved modestly over time, but only after adjustment for innate patient risk factors. As more high-risk CHD infants undergo cardiac surgery and survive, a growing population will require significant societal resources.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Patient genotypes impact survival after surgery for isolated congenital heart disease

BACKGROUND

Survival after cardiac surgery in infancy requires adaptive responses from oxidative stress management and vascular regulation pathways. We tested the hypothesis that genetic variation in these pathways influences postoperative survival in nonsyndromic congenital heart disease children.

METHODS

This is an analysis of a cohort of nonsyndromic congenital heart disease patients who underwent cardiac surgery with cardiopulmonary bypass before 6 months of age (n=422). Six single nucleotide polymorphisms (SNPs) in six genes involved in oxidative stress and vascular response pathways, identified through a priori literature search, were tested for effects on transplant-free survival. Survival curves, adjusting for confounding covariates, were calculated using the Cox proportional hazard models.

RESULTS

Long-term survival was strongly associated with vascular endothelial growth factor A gene SNP rs833069 (p=7.03×10(-4)) and superoxide dismutase 2 gene SNP rs2758331 (p=0.019). To test for joint effects of the two SNPs on transplant-free survival, the genotypes were grouped to form a risk score reflecting the cumulative number of risk alleles (0 to 4 alleles per patient). A higher risk score based on the VEGFA and SOD2 SNP genotypes was associated with worse transplant-free survival (p=3.02×10(-4)) after confounder adjustment. The total burden of risk alleles was additive; subjects with the highest risk score of 4 (n=59 subjects, 14.2% of the cohort) had a total covariate-adjusted hazard ratio of 15.64 for worse transplant-free survival.

CONCLUSIONS

After cardiac surgery, infants who are homozygous for the high-risk alleles for both the VEGFA and SOD2 SNPs have an approximately 16-fold increased risk of death or heart transplant, suggesting that genetic variants are important modifiers of survival after surgery for congenital heart disease.

Cerebral blood flow changes during rat cardiopulmonary bypass and deep hypothermic circulatory arrest model: a preliminary study

Cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA) are important techniques often used in complex cardiac surgery for neonates and infants heart diseases. Cerebral blood flow (CBF) serves as an important physiological parameter and provides valuable hemodynamic information during the surgery. Laser speckle imaging (LSI), as an optical imaging technique, can provide full-field CBF information with a high spatiotemporal resolution. In this preliminary study, we acquired the real-time CBF images with a self-developed miniaturized head-mounted LSI system during the whole CPBillHCA rat model. Relative CBF velocity in veins and arteries in bilateral hemispheres dropped significantly during cooling period and reached to nearly zero during arrest period (n = 5). More interestingly, two rats showing more dramatic CBF variations in veins than in arteries during cooling period exhibited severe cerebral edema after surgery. The real-time full-field CBF imaging during the CPBillHCA surgery could add more insights into the operation and be utilized to study the surgical protocols with the ultimate goal ofreducing neurologic injury after surgery.

Use of diagnostic information submitted to the United Kingdom Central Cardiac Audit Database: development of categorisation and allocation algorithms

OBJECTIVE

To categorise records according to primary cardiac diagnosis in the United Kingdom Central Cardiac Audit Database in order to add this information to a risk adjustment model for paediatric cardiac surgery.

DESIGN

Codes from the International Paediatric Congenital Cardiac Code were mapped to recognisable primary cardiac diagnosis groupings, allocated using a hierarchy and less refined diagnosis groups, based on the number of functional ventricles and presence of aortic obstruction.

SETTING

A National Clinical Audit Database. Patients Children undergoing cardiac interventions: the proportions for each diagnosis scheme are presented for 13,551 first patient surgical episodes since 2004.

RESULTS

In Scheme 1, the most prevalent diagnoses nationally were ventricular septal defect (13%), patent ductus arteriosus (10.4%), and tetralogy of Fallot (9.5%). In Scheme 2, the prevalence of a biventricular heart without aortic obstruction was 64.2% and with aortic obstruction was 14.1%; the prevalence of a functionally univentricular heart without aortic obstruction was 4.3% and with aortic obstruction was 4.7%; the prevalence of unknown (ambiguous) number of ventricles was 8.4%; and the prevalence of acquired heart disease only was 2.2%. Diagnostic groups added to procedural information: of the 17% of all operations classed as "not a specific procedure", 97.1% had a diagnosis identified in Scheme 1 and 97.2% in Scheme 2.

CONCLUSIONS

Diagnostic information adds to surgical procedural data when the complexity of case mix is analysed in a national database. These diagnostic categorisation schemes may be used for future investigation of the frequency of conditions and evaluation of long-term outcome over a series of procedures.

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.

A mortality risk model to adjust for case mix in UK paediatric cardiac surgery

Background

Congenital heart disease (CHD) is a relatively common disorder in childhood, affecting approximately 8–9 per 1000 live-born infants annually in the UK. CHD often involves serious abnormalities and is an important cause of childhood mortality, morbidity and disability. It is generally recognised that it is important and valuable to monitor outcomes in cardiac surgery and that, to do so fairly and effectively, one needs to risk stratify the case load of each unit. There is evidence that, since outcome monitoring in adult cardiac surgery became mandatory and routine, outcomes have improved. At present, no process for routinely monitoring risk-adjusted outcomes in paediatric cardiac surgery exists.

Objectives

To establish whether or not a risk model can be developed that is fit for the purpose of adjusting for case mix severity to facilitate routine monitoring of outcomes for paediatric cardiac surgery in the UK and to assess whether or not and how diagnostic information can augment procedural information in risk adjustment.

Methods

Data from the Central Cardiac Audit Database (CCAD) for all cardiac surgery procedures, excluding reoperations within 30 days, performed in the UK for patients < 16 years between 2000 and 2010 (38,597 patient episodes) were included: 70% for model development and 30% quarantined for validation. The outcome was 30-day survival, as supplied to CCAD through the Central Register of NHS patients (now the Medical Research Information Service). The CCAD defines 36 ‘specific procedures’. Nine of these were merged as a ‘low-volume specific procedure’ group (< 90 cases each in the entire development set). Unassigned cases were grouped as ‘not a specific procedure’. Twenty-four ‘primary’ cardiac diagnoses and separately a categorisation of ‘univentricular’ status were defined using a hierarchical algorithm developed by the study team based on International Paediatric and Congenital Cardiac codes. Comorbidities considered included prematurity (< 37 weeks' gestation), Down syndrome, constellations of features that constitute a recognised syndrome, congenital structural defects of organs other than the heart and acquired conditions. Other candidate variables included use of bypass and patient age, weight and sex. Data were analysed using logistic regression.

Results

In the development set, there were 25,665 episodes that resulted in survival to 30 days, 693 episodes for which the vital status at 30 days was unknown and 854 episodes that resulted in death within 30 days in the development set (mortality 3.2% overall). The risk model developed includes the following factors: specific procedure, primary cardiac diagnosis grouped into low-, medium- and high-risk categories, univentricular heart status, age band (neonate, infant, child), continuous age, continuous weight, presence of a comorbidity other than Down syndrome and use of bypass. To account for decreasing mortality over time in the development set, a binary indicator for operations performed after 1 January 2007 is also included in the model. We were able to calculate a risk score for 95% of cases in the test set: weight was missing in 5% of cases. Data completeness improved over time. The proposed model discriminated well: the area under the receiver operating characteristic curve (AUC) for the test set was 0.77 (0.81 for post-2007 data). Removal of all but procedural information gave a reduced AUC of 0.72. The model performed well across the spectrum of predicted risk in the entire data set, but there was underestimation of mortality risk in the test set among neonates operated from 2007.

Limitations

An important limitation is that the model pertains to short-term 30-day outcomes (not long-term outcomes) and is designed for the purpose of routine monitoring for quality assurance rather than bedside-type predictions for individual patients. Over the recent period in the validation set (since 2007), the model was found to underestimate risk at the very high-risk end (> 10% risk), in particular among neonates. This indicates that risk adjustment based on the current parameterisation of the model will potentially give an unduly negative impression of outcomes at those centres with a high proportion of high-risk cases. Finally, any risk model used for ongoing quality improvement initiatives needs to be regularly updated as data quality improves and clinical practice evolves.

Conclusions

For the first time diagnostic information has been successfully incorporated into risk adjustment for short-term outcomes in this patient group, which added discriminatory power. The risk model is fit for purpose, although the underestimation of risk in recent neonates is an important caveat. Several centres have expressed an interest in piloting the risk model and the accompanying monitoring tool. Future work includes developing software to generate variable life-adjusted display charts within units using the risk model; using the risk model to explore trends in case mix over time; and informing future work in evaluating long-term outcomes for children with CHD.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

The effect of preoperative nutritional status on postoperative outcomes in children undergoing surgery for congenital heart defects in San Francisco (UCSF) and Guatemala City (UNICAR)

OBJECTIVE

The objective of this study was to determine the association between preoperative nutritional status and postoperative outcomes in children undergoing surgery for congenital heart defects (CHD).

METHODS

Seventy-one patients with CHD were enrolled in a prospective, 2-center cohort study. We adjusted for baseline risk differences using a standardized risk adjustment score for surgery for CHD. We assigned a World Health Organization z score for each subject's preoperative triceps skin-fold measurement, an assessment of total body fat mass. We obtained preoperative plasma concentrations of markers of nutritional status (prealbumin, albumin) and myocardial stress (B-type natriuretic peptide [BNP]). Associations between indices of preoperative nutritional status and clinical outcomes were sought.

RESULTS

Subjects had a median (interquartile range [IQR]) age of 10.2 (33) months. In the University of California at San Francisco (UCSF) cohort, duration of mechanical ventilation (median, 19 hours; IQR, 29 hours), length of intensive care unit stay (median, 5 days; IQR 5 days), duration of any continuous inotropic infusion (median, 66 hours; IQR 72 hours), and preoperative BNP levels (median, 30 pg/mL; IQR, 75 pg/mL) were associated with a lower preoperative triceps skin-fold z score (P < .05). Longer duration of any continuous inotropic infusion and higher preoperative BNP levels were also associated with lower preoperative prealbumin (12.1 ± 0.5 mg/dL) and albumin (3.2 ± 0.1; P < .05) levels.

CONCLUSIONS

Lower total body fat mass and acute and chronic malnourishment are associated with worse clinical outcomes in children undergoing surgery for CHD at UCSF, a resource-abundant institution. There is an inverse correlation between total body fat mass and BNP levels. Duration of inotropic support and BNP increase concomitantly as measures of nutritional status decrease, supporting the hypothesis that malnourishment is associated with decreased myocardial function.

New White Matter Brain Injury After Infant Heart Surgery Is Associated With Diagnostic Group and the Use of Circulatory Arrest

Background—

Abnormalities on magnetic resonance imaging scans are common both before and after surgery for congenital heart disease in early infancy. The aim of this study was to prospectively investigate the nature, timing, and consequences of brain injury on magnetic resonance imaging in a cohort of young infants undergoing surgery for congenital heart disease both with and without cardiopulmonary bypass.

Methods and Results—

A total of 153 infants undergoing surgery for congenital heart disease at <8 weeks of age underwent serial magnetic resonance imaging scans before and after surgery and at 3 months of age, as well as neurodevelopmental assessment at 2 years of age. White matter injury (WMI) was the commonest type of injury both before and after surgery. It occurred in 20% of infants before surgery and was associated with a less mature brain. New WMI after surgery was present in 44% of infants and at similar rates after surgery with or without cardiopulmonary bypass. The most important association was diagnostic group ( P <0.001). In infants having arch reconstruction, the use and duration of circulatory arrest were significantly associated with new WMI. New WMI was also associated with the duration of cardiopulmonary bypass, postoperative lactate level, brain maturity, and WMI before surgery. Brain immaturity but not brain injury was associated with impaired neurodevelopment at 2 years of age.

Conclusions—

New WMI is common after surgery for congenital heart disease and occurs at the same rate in infants undergoing surgery with and without cardiopulmonary bypass. New WMI is associated with diagnostic group and, in infants undergoing arch surgery, the use of circulatory arrest.

Congenital heart disease affects cerebral size but not brain growth

Infants with congenital heart disease (CHD) have delayed brain maturation and alterations in brain volume. Brain metrics is a simple measurement technique that can be used to evaluate brain growth. This study used brain metrics to test the hypothesis that alterations in brain size persist at 3 months of age and that infants with CHD have slower rates of brain growth than control infants. Fifty-seven infants with CHD underwent serial brain magnetic resonance imaging (MRI). To evaluate brain growth across the first 3 months of life, brain metrics were undertaken using 19 tissue and fluid spaces shown on MRIs performed before surgery and again at 3 months of age. Before surgery, infants with CHD have smaller frontal, parietal, cerebellar, and brain stem measures (p < 0.001). At 3 months of age, alterations persisted in all measures except the cerebellum. There was no difference between control and CHD infants in brain growth. However, the cerebellum trended toward greater growth in infants with CHD. Somatic growth was the primary factor that related to brain growth. Presence of focal white matter lesions before and after surgery did not relate to alterations in brain size or growth. Although infants with CHD have persistent alterations in brain size at 3 months of age, rates of brain growth are similar to that of healthy term infants. Somatic growth was the primary predictor of brain growth, emphasizing the importance of optimal weight gain in this population.

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.

Selective cerebro-myocardial perfusion in complex congenital aortic arch pathology: a novel technique

Simultaneous cerebro-myocardial perfusion has been described in neonatal and infant arch surgery, suggesting a reduction in cardiac morbidity. Here reported is a novel technique for selective cerebral perfusion combined with controlled and independent myocardial perfusion during surgery for complex or recurrent aortic arch lesions. From April 2008 to April 2011, 10 patients with arch pathology underwent surgery (two hypoplastic left heart syndrome [HLHS], four recurrent arch obstruction, two aortic arch hypoplasia + ventricular septal defect [VSD], one single ventricle + transposition of the great arteries + arch hypoplasia, one interrupted aortic arch type B + VSD). Median age was 63 days (6 days-36 years) and median weight 4.0 kg (1.6-52). Via midline sternotomy, an arterial cannula (6 or 8 Fr for infants) was directly inserted into the innominate artery or through a polytetrafluoroethylene (PTFE) graft (for neonates <2.0 kg). A cardioplegia delivery system was inserted into the aortic root. Under moderate hypothermia, ascending and descending aorta were cross-clamped, and "beating heart and brain" aortic arch repair was performed. Arch repair was composed of patch augmentation in five, end-to-side anastomosis in three, and replacement in two patients. Average cardiopulmonary bypass time was 163 ± 68 min (71-310). In two patients only (one HLHS, one complex single ventricle), a period of cardiac arrest was required to complete intracardiac repair. In such cases, antegrade blood cardioplegia was delivered directly via the same catheter used for selective myocardial perfusion. Average time of splanchnic ischemia during cerebro-myocardial perfusion was 39 ± 18 min (17-69). Weaning from cardiopulmonary bypass was achieved without inotropic support in three and with low dose in seven patients. One patient required veno-arterial extracorporeal membrane oxygenation. Four patients, body weight <3.0 kg, needed delayed sternal closure. No neurologic dysfunction was noted. Renal function proved satisfactory in all, while liver function was adequate in all but one. The present experience suggests that selective and independent cerebro-myocardial perfusion is feasible in patients with complex or recurrent aortic arch disease, starting from premature newborn less than 2.0 kg of body weight to adults. The technique is as safe as previously reported methods of cerebro-myocardial perfusion and possibly more versatile.

Children with genetic disorders undergoing open-heart surgery: are they at increased risk for postoperative complications?

OBJECTIVES

Children with congenital heart disease and genetic disorders may be at increased risk for postoperative mortality and morbidity compared with children with congenital heart disease alone. The aim of the present study was to determine differences in postcardiopulmonary bypass outcome between these two groups.

DESIGN

Prospective cohort study.

SETTING

Tertiary university children's hospital.

PATIENTS

We enrolled 211 infants (<1 yr) who underwent bypass surgery for congenital heart disease. Data on perioperative course were compared between infants with and without genetic disorders. Univariate analysis was followed by regression analysis to control for confounders.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We enrolled 148 infants without and 63 infants with a genetic disorder. The majority of infants with genetic disorders had trisomy 21 (n = 32), six had microdeletion 22q11, and 25 had other genetic disorders. There was no significant difference in mortality between infants with and without genetic disorders. An underlying genetic disorder was an independent risk factor for renal insufficiency (p = .003) and reintubation (p = .02). Trisomy 21 was an independent risk factor for chylothorax (p = .01) and sepsis (p = .05). The length of hospital stay was longer in infants with genetic disorders other than trisomy 21 compared with infants with trisomy 21 (p = .009).

CONCLUSIONS

Infants with congenital heart disease and genetic disorders are not at increased risk for postoperative mortality. However, a genetic disorder is a risk factor for reintubation and renal insufficiency, whereas infants with trisomy 21 have a higher risk of chylothorax and sepsis. Intensive care providers need to be aware of these differences in morbidity to improve management decisions and parental counseling.

Perioperative management of low birth weight infants for open-heart surgery

Infants of birth weight ≤2500 g are termed low birth weight (LBW). These children often have considerable morbidity from prematurity and intra-uterine growth restriction. Additionally, LBW infants have increased risk for cardiac and noncardiac congenital anomalies and may require surgery. Primary rather than palliative surgical repair of cardiac lesions has been preferred in recent years. However, LBW remains a risk factor for increased mortality and morbidity after open-heart surgery (OHS). There is a paucity of information about the anesthetic challenges presented by LBW infants undergoing OHS. This review summarizes the perioperative issues of relevance to anesthesiologists who manage these high-risk patients. Emphasis is placed on management concerns that are unique to LBW infants. Retrospective data from the authors' institution are provided for those aspects of anesthetic care that lack published studies. Successful outcome often requires substantial hospital resources and collaborative multi-disciplinary effort.

The importance of blood lactate clearance as a predictor of early mortality following the modified Norwood procedure

OBJECTIVE

Optimisation of Norwood physiology, with focus on systemic perfusion, has beneficial effects on haemodynamic stability and perioperative mortality following the Norwood procedure for hypoplastic left heart syndrome. Early identification of high-risk patients during the postoperative phase might allow for institution of alternative management strategies with the possibility of avoiding poor outcome. Several studies have suggested that arterial blood lactate level, as an index of systemic perfusion and oxygen delivery, can to some extent predict mortality following paediatric cardiac surgery, though these studies have included heterogeneous groups of patients with only few Norwood patients. We sought to determine whether the blood lactate profile could be used to derive a simple, clinically applicable decision algorithm to direct therapy in a pre-emptive manner and perhaps identify patients for elective extracorporeal life support following the Norwood procedure.

METHODS

We retrospectively analysed all patients at our institution who had undergone modified Norwood procedures between March 2002 and May 2008. All patients had received right ventricle-pulmonary artery conduits. Patients with systemic-pulmonary shunts were excluded. Outcome measures included 7-day and 30-day mortality. Serial arterial blood lactate measurements were taken in all patients for at least 72h. Conditional inference tree modelling was used to determine the discriminatory value of the lactate profile and other pre- and intra-operative risk factors in terms of selecting survivors.

RESULTS

As many as 221 patients were included. The 7-day ICU mortality was 26/219 (11.8%) with total 30-day mortality of 35/219 (15.8%). There were 21 interstage deaths. Mortality modelling demonstrated that an inability to clear blood lactate levels to <6.76mmoll(-1) within the first 24h was highly discriminatory in terms of predicting death within the first 30 days. A total of 11 out of 12 patients in this group died. Other risk factors examined, including weight, ascending aorta size, cardiopulmonary bypass and ischaemic times, were not as predictive in our model.

CONCLUSION

We have identified minimum blood lactate level within the first 24h after the Sano-Norwood procedure as a highly discriminatory predictor of perioperative mortality. These patients might benefit from elective institution of early mechanical circulatory support.

External validity of the pediatric cardiac quality of life inventory

PURPOSE

The Pediatric Cardiac Quality of Life Inventory (PCQLI) is a disease-specific, health-related quality of life (HRQOL) measure for pediatric heart disease (HD). The purpose of this study was to demonstrate the external validity of PCQLI scores.

METHODS

The PCQLI development site (Development sample) and six geographically diverse centers in the United States (Composite sample) recruited pediatric patients with acquired or congenital HD. Item response option variability, scores [Total (TS); Disease Impact (DI) and Psychosocial Impact (PI) subscales], patterns of correlation, and internal consistency were compared between samples.

RESULTS

A total of 3,128 patients and parent participants (1,113 Development; 2,015 Composite) were analyzed. Response option variability patterns of all items in both samples were acceptable. Inter-sample score comparisons revealed no differences. Median item-total (Development, 0.57; Composite, 0.59) and item-subscale (Development, DI 0.58, PI 0.59; Composite, DI 0.58, PI 0.56) correlations were moderate. Subscale-subscale (0.79 for both samples) and subscale-total (Development, DI 0.95, PI 0.95; Composite, DI 0.95, PI 0.94) correlations and internal consistency (Development, TS 0.93, DI 0.90, PI 0.84; Composite, TS 0.93, DI 0.89, PI 0.85) were high in both samples.

CONCLUSION

PCQLI scores are externally valid across the US pediatric HD population and may be used for multi-center HRQOL studies.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Morbidity and mortality after surgery for congenital cardiac disease in the infant born with low weight

OBJECTIVE

Low weight at birth is a risk factor for increased mortality in infants undergoing surgery for congenitally malformed hearts. There has been a trend towards performing surgery in patients early, and for amenable lesions, in a single stage rather than following initial palliative procedures. Our goal was to report on the current incidences of morbidities and mortality in infants born with low weight and undergoing surgery for congenital cardiac disease.

METHODS

We made a retrospective review of the data from patients meeting our criterions for entry from July, 2000, through July, 2004. The criterions for inclusion were weight at birth less than or equal to 2500 grams, and congenital cardiac malformations requiring surgery during the initial hospitalization. A criterion for exclusion was isolated persistent patency of the arterial duct. We assessed preoperative, intraoperative, and postoperative variables.

RESULTS

We found a total of 105 patients meeting the criterions for inclusion. The median weight at birth was 2130 grams, and median gestational age was 36 weeks. The most common morbidity identified was infections of the blood stream. Infections, and chronic lung disease, were associated with increased length of stay. Survival overall was 76%. Patients with hypoplastic left heart syndrome, or a variant thereof, had the lowest survival, of 62%. The needs for cardiopulmonary resuscitation, or extracorporeal membrane oxygenation, post-operatively were the only factors identified as independent risk factors for mortality.

CONCLUSION

Patients undergoing surgery during infancy for congenital cardiac disease who are born with low weight have a higher mortality and morbidity than those born with normal weight.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Neuroprotection in infant heart surgery

Neonatal hypoxic-ischemic encephalopathy, prematurity, sepsis-meningitis, and serious forms of complex congenital heart disease requiring infant heart surgery are just a few examples of disorders that share high mortality and morbidity rates. Newborn heart surgery represents a period of planned and deliberate ischemia-reperfusion injury, which is obliged to occur to cure or palliate complex forms of congenital heart disease. Advances in cardiothoracic surgical and anesthetic techniques, including cardiopulmonary bypass and deep hypothermic circulatory arrest, have substantially decreased mortality, expanding the horizon to address functional neurologic and cardiac outcomes in long-term survivors. Interest in the functional status of survivors now stretches beyond the newborn period to childhood, adolescence, and adulthood.

Results with all blood retrograde microplegia as a myocardial protection strategy for complex neonatal arch reconstruction

Neonatal arch reconstructions present a challenge for myocardial protection. We report our results for eight patients treated with intermittent cold all blood retrograde cardioplegia during arch reconstruction using continuous selective normothermic cerebral perfusion. Over a 10-month period eight consecutive neonates underwent complex arch reconstruction. Mean age was 8.4 days (range 2-23); weight 3.1 kg (range 2.7-3.8). Diagnosis was hypoplastic left heart syndrome (5), interrupted aortic arch/ventriculoseptal defect (2), and complex AP window (1). Mean cardiopulmonary bypass time was 149 minutes (range 80-201), mean cross-clamp time was 74 (range 51-101). All patients had primary chest closure and none required extra-corporeal membrane oxigenation. One patient (12%) had a period of low cardiac output syndrome, which resolved with high dose inotropes. All patients were discharged alive and well. Intermittent all blood retrograde microplegia is an effective myocardial protection strategy for complex neonatal arch reconstruction. Postoperative myocardial function is very good. This protection approach facilitates continuous selective normothermic cerebral perfusion.

Epidemiologic features of the presentation of critical congenital heart disease: implications for screening

OBJECTIVE

Critical congenital heart disease has been proposed as a target of newborn screening. This study aimed to define the incidence and timing of significant physiologic compromise attributable to critical congenital heart disease as well as the distribution of vulnerable lesions. These descriptive parameters must be defined to evaluate the impact and feasibility of any proposed screening strategy.

METHODS

A retrospective cohort study of neonates who had critical congenital heart disease and were admitted to a single institution was conducted. Critical congenital heart disease was defined as congenital heart disease that required invasive intervention or resulted in death in the first 30 days of life. Significant physiologic compromise was defined by severe metabolic acidosis, seizure, cardiac arrest, or laboratory evidence of renal or hepatic injury before invasive intervention. Significant physiologic compromise was classified as potentially preventable when it occurred as a result of undiagnosed congenital heart disease after 12 hours of life.

RESULTS

Significant physiologic compromise occurred in 76 (15.5%) of 490 patients, and potentially preventable significant physiologic compromise occurred in 33 (6.7%) of 490 patients. Most (83%) significant physiologic compromise as a result of unrecognized congenital heart disease occurred after 12 hours of age. A total of 90.9% of cases of potentially preventable significant physiologic compromise had aortic arch obstruction. The incidence of potentially preventable significant physiologic compromise as a result of congenital heart disease in the general population is estimated to be 1 per 15,000 to 1 per 26,000 live births.

CONCLUSIONS

The incidence and timing of significant physiologic compromise as a result of critical congenital heart disease seems amenable to postnatal screening. Any viable screening strategy must be sensitive for lesions with aortic arch obstruction.

Critical heart disease in the neonate: presentation and outcome at a tertiary care center

OBJECTIVE

To define the modes of presentation, incidence of major organ dysfunction, predictors of hospital mortality, and adverse outcomes in neonates with critical heart disease admitted to a tertiary care center.

DESIGN

Retrospective chart review.

SETTING

A tertiary care pediatric cardiac intensive care unit and neonatal intensive care unit.

PATIENTS

The medical records for all neonates (< or = 30 days of age) with heart disease admitted to the cardiac intensive care unit or neonatal intensive care unit between October 1, 2002, and September 30, 2003, were reviewed.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

A total of 190 neonates met inclusion criteria during this 1-yr period, of which 146 (77%) had at least one surgical procedure. Single ventricle heart disease was present in 42%. The most common mode of presentation was following a prenatal diagnosis (53%), followed by diagnosis in the newborn nursery (38%) and diagnosis after newborn hospital discharge (8%). The most common presenting findings in the newborn nursery were isolated murmur (38%) or cyanosis (32%), while circulatory collapse (38%) was the most common presentation after discharge. For the entire study cohort, 13% had a known genetic syndrome, 23% had a major noncardiac congenital anomaly, and 16% weighed < 2.5 kg. The hospital mortality for the entire cohort was 7.4%. Risk factors associated with an increased risk of hospital mortality included younger age at admission, higher number of cardiopulmonary bypass runs, and need for postoperative cardiopulmonary resuscitation. Total hospital length of stay was > 1 month in 17% of neonates.

CONCLUSIONS

In patients with complex congenital heart disease, including nearly half with single ventricle heart disease, neonatal hospital mortality was 7%. These patients have a high frequency of multiple congenital anomalies, genetic syndromes, low birth weight, and prolonged length of stay.

Comparing the clinical and economic effects of clinical examination, pulse oximetry, and echocardiography in newborn screening for congenital heart defects: A probabilistic cost-effectiveness model and value of information analysis

Objectives: Congenital heart defects (CHD) are an important cause of death and morbidity in early childhood, but the effectiveness of alternative newborn screening strategies in preventing the collapse or death—before diagnosis—of infants with treatable but life-threatening defects is uncertain. We assessed their effectiveness and efficiency to inform policy and research priorities.

Methods: We compared the effectiveness of clinical examination alone and clinical examination with either pulse oximetry or screening echocardiography in making a timely diagnosis of life-threatening CHD or in diagnosing clinically significant CHD. We contrasted their cost-effectiveness, using a decision-analytic model based on 100,000 live births, and assessed future research priorities using value of information analysis.

Results: Clinical examination alone, pulse oximetry, and screening echocardiography achieved 34.0, 70.6, and 71.3 timely diagnoses per 100,000 live births, respectively. This finding represents an additional cost per additional timely diagnosis of £4,894 and £4,496,666 for pulse oximetry and for screening echocardiography. The equivalent costs for clinically significant CHD are £1,489 and £36,013, respectively. Key determinants of cost-effectiveness are detection rates and screening test costs. The false-positive rate is very high with screening echocardiography (5.4 percent), but lower with pulse oximetry (1.3 percent) or clinical examination alone (.5 percent).

Conclusions: Adding pulse oximetry to clinical examination is likely to be a cost-effective newborn screening strategy for CHD, but further research is required before this policy can be recommended. Screening echocardiography is unlikely to be cost-effective, unless the detection of all clinically significant CHD is considered beneficial and a 5 percent false-positive rate acceptable.

Regional and central venous oxygen saturation monitoring following pediatric cardiac surgery: concordance and association with clinical variables

OBJECTIVE

To compare changes in regional cerebral or flank oxygen saturation measured by near-infrared spectroscopy with changes in central venous oxygen saturation (ScvO2) and to determine clinical variables associated with these changes.

DESIGN

Prospective observational cohort study.

SETTING

University tertiary care center, pediatric cardiac intensive care unit.

PATIENTS

Seventy postoperative congenital cardiac surgical patients (median age 0.3 yrs; interquartile range 0.02-0.46 yrs).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We measured temporally correlated regional oxygen saturation (rSO2) with hematologic (hematocrit), biochemical (arterial blood gas, ScvO2, and lactate) and physiologic (temperature, heart rate, mean blood pressure, and pulse oximetry) variables in the first postoperative day. Cerebral and flank rSO2 were strongly correlated with ScvO2, in both cyanotic or acyanotic patients and single- or two-ventricle physiology with and without aortic arch obstruction (all p < .001). However, individual values had wide limits of agreement on Bland-Altman analysis. The correlations of change in these measurements were weaker but still significant (all p < .0001), again with wide limits of agreement. Similar direction of change in cerebral rSO2 and ScvO2 was present 64% (95% confidence interval, 55-73%) of the time. Change in arterial pressure of carbon dioxide (delta PaCO2) was associated with cerebral delta rSO2 (delta PaCO2 beta = 0.35, p < .0001) but not flank delta rSO2 or delta ScvO2. A pattern of relative cerebral desaturation (flank rSO2 > cerebral rSO2) was noted in a majority of patients (81%) with two-site monitoring regardless of bypass method or age.

CONCLUSIONS

Neither individual values nor changes in rSO2 are interchangeable measures of ScvO2 in postoperative pediatric cardiac patients. The unique relationship between changes in PaCO2 and cerebral rSO2 supports the hypothesis that cerebral near-infrared spectroscopy monitors regional cerebral oxygenation. Clinical application of this monitor must include recognition of the clinical variables that affect regional brain oxygenation.

Temporal and Anatomic Risk Profile of Brain Injury With Neonatal Repair of Congenital Heart Defects

BACKGROUND AND PURPOSE

Brain injury is common in newborns with congenital heart disease (CHD) requiring neonatal surgery. The purpose of this study is to define the risk factors for preoperative and postoperative brain injuries and their association with functional cardiac anatomic groups.

METHODS

Sixty-two neonates with CHD were studied with preoperative MRI, and 53 received postoperative scans. Clinical and therapeutic characteristics were compared in newborns with and without newly acquired brain injuries. A subset of 16 consecutive patients was monitored with intraoperative cerebral near-infrared spectroscopy.

RESULTS

Brain injury was observed in 56% of patients. Preoperative brain injury, seen in 39%, was most commonly stroke and was associated with balloon atrial septostomy (P=0.002). Postoperative brain injury, seen in 35%, was most commonly white matter injury and was particularly common in neonates with single-ventricle physiology and aortic arch obstruction (P=0.001). Risk factors associated with acquired postoperative brain injury included cardiopulmonary bypass (CPB) with regional cerebral perfusion (P=0.01) and lower intraoperative cerebral hemoglobin oxygen saturation during the myocardial ischemic period of CPB (P=0.008). In a multivariable model, new postoperative white matter injury was specifically associated with low mean blood pressure during the first postoperative day (P=0.04).

CONCLUSIONS

Specific modifiable risk factors can be identified for preoperative and postoperative white matter injury and stroke associated with neonatal surgery for CHD. The high incidence of postoperative injury observed despite new methodologies of CPB indicates the need for ongoing evaluation to optimize neurological outcome.

New developments in the treatment of hypoplastic left heart syndrome

In the current decade, the prognosis of newborns with hypoplastic left heart syndrome, previously considered a uniformly fatal condition, has dramatically improved through refinement of rapidly evolving treatment strategies. These strategies include various modifications of staged surgical reconstruction, orthotopic heart transplantation, and hybrid palliation using ductal stenting and bilateral pulmonary artery banding. The variety of treatment approaches are based on different surgical philosophies, and each approach has its unique advantages and disadvantages. Nonetheless, multiple experienced centers have reported improved outcomes in each one of those modalities. The purpose of this review is to outline recent developments in the array of currently available management strategies for neonates with hypoplastic left heart syndrome. Because the vast majority of deaths in this patient population occur within the first months of life, the focus of the review will be evaluation of the impact of these management strategies on survival in the neonatal and infant periods.

Delayed diagnosis of congenital heart disease worsens preoperative condition and outcome of surgery in neonates

OBJECTIVES

To assess whether the route by which neonatal congenital heart disease (CHD) is first recognised influences outcome after surgery.

METHODS

Surgical neonates admitted to a tertiary cardiac unit between March 1999 and February 2002 were retrospectively reviewed with analysis of risk factors for outcome. Three routes to initial recognition of CHD were compared: antenatal diagnosis, detection on the postnatal ward, and presentation after discharge to home. Outcome measures were mortality and duration of perioperative ventilation.

RESULTS

286 neonates had cardiac surgery with a median duration of ventilation of 101 h and in-hospital mortality of 12%. Recognition of CHD was antenatal in 20%, on the postnatal ward in 55% and after discharge to home in 25%. Multiple regression analyses, including the cardiac diagnosis, associated problems and other risk factors, indicated that severe cardiovascular compromise on admission to the cardiac unit was significantly related to mortality and prolonged ventilation. Considered in isolation, the route to recognition of heart disease did not influence mortality or ventilation time. Route to initial recognition did, however, influence the patient's condition on admission to the cardiac unit. Cardiovascular compromise and end organ dysfunction were least likely when recognition was antenatal and most common when presentation followed discharge to home.

CONCLUSION

The setting in which neonatal CHD is first recognised has an impact on preoperative condition, which in turn influences postoperative progress and survival after surgery. Optimal screening procedures and access to specialist care will improve outcome for neonates undergoing cardiac surgery.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Outcome in neonates with congenital heart disease referred for respiratory extracorporeal membrane oxygenation

AIM

To evaluate the proportion of neonates referred for extracorporeal membrane oxygenation (ECMO) support in the modern era of advanced conventional treatments for respiratory failure who actually had congenital heart disease (CHD), and to assess the impact of this diagnostic route on patient condition and outcome.

METHODS

A retrospective case-note review of neonatal ECMO and cardiac admissions to a single, tertiary ECMO and cardiac intensive care unit (ICU) between March 1999 and February 2002.

RESULTS

287 symptomatic neonates presented to the ICU with previously undiagnosed cardiac or respiratory disease. Eighty-two with presumed respiratory failure were referred for ECMO, and 205 with suspected CHD were referred for cardiac evaluation. Eight (10%) ECMO referrals, all with presumed persistent pulmonary hypertension of the newborn (PPHN), were found to have CHD (transposition: 3; total anomalous pulmonary venous connection: 3; left heart obstructive lesions: 2). Mortality in this group was 50%, compared with 11% for correctly identified CHD patients (odds ratio 8.2, 95% CI 1.92, 35.4, p<0.01). For all neonates with CHD, the risk of death was increased by the presence of cardiovascular collapse and end-organ dysfunction at presentation to the ICU (p<0.01 for both).

CONCLUSION

Neonates with CHD may present as severe "PPHN" via the ECMO service. Poor outcome in these patients relates to the high incidence of cardiovascular collapse and end-organ dysfunction. Early echocardiography is recommended for neonates with presumed PPHN. Neonatal ECMO support should be based in centres with cardiac surgical services.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk factors for mortality in 137 pediatric cardiac intensive care unit patients managed with extracorporeal membrane oxygenation

OBJECTIVE

To identify factors associated with mortality in children with heart disease managed with extracorporeal membrane oxygenation (ECMO).

DESIGN

Retrospective chart review.

SETTING

Tertiary care university-affiliated children's hospital.

PATIENTS

All pediatric cardiac intensive care unit patients managed with ECMO between January 1, 1995, and June 30, 2001.

INTERVENTIONS

None.

RESULTS

During the study period, 137 patients were managed with ECMO in the pediatric cardiac intensive care unit. Of the 137 patients, 80 (58%) survived > or =24 hrs after decannulation, and 53 (39%) survived to hospital discharge. Patients managed with ECMO following cardiac surgery were analyzed separately from patients not in the postoperative period. Factors associated with an increased probability of mortality in the postoperative patients were age <1 month, male gender, longer duration of mechanical ventilation before ECMO, and development of renal or hepatic dysfunction while on ECMO. Single ventricle physiology and failure to separate from cardiopulmonary bypass were not associated with an increased risk of mortality. Cardiac physiology and indication for ECMO were not associated with mortality rate. Although longer duration of ECMO was not associated with increased mortality risk, patients with longer duration of ECMO were less likely to survive without heart transplantation.

CONCLUSIONS

In a series of 137 patients managed with ECMO in a pediatric cardiac intensive care unit, survival to hospital discharge was 39%. In postoperative patients only, mortality risk was increased in males, patients <1 month old, patients with a longer duration of mechanical ventilation before initiation of ECMO, and patients who developed renal or hepatic failure while on ECMO.