Survival of Children With Hypoplastic Left Heart Syndrome

The Association of Race and Ethnicity with Mortality in Pediatric Patients with Congenital Heart Disease: a Systematic Review

CONTEXT

Congenital heart disease (CHD) is a common condition with high morbidity and mortality and is subject to racial and ethnic health disparities.

OBJECTIVE

To conduct a systematic review of the literature to identify differences in mortality in pediatric patients with CHD based on race and ethnicity.

DATA SOURCES

Legacy PubMed (MEDLINE), Embase (Elsevier), and Scopus (Elsevier) STUDY SELECTION: English language articles conducted in the USA focused on mortality based on race and ethnicity in pediatric patients with CHD.

DATA EXTRACTION

Two independent reviewers assessed studies for inclusion and performed data extraction and quality assessment. Data extraction included mortality based on patient race and ethnicity.

RESULTS

There were 5094 articles identified. After de-duplication, 2971 were screened for title and abstract content, and 45 were selected for full-text assessment. Thirty studies were included for data extraction. An additional 8 articles were identified on reference review and included in data extraction for a total of 38 included studies. Eighteen of 26 studies showed increased risk of mortality in non-Hispanic Black patients. Results were heterogenous in Hispanic patients with eleven studies of 24 showing an increased risk of mortality. Results for other races demonstrated mixed outcomes.

LIMITATIONS

Study cohorts and definitions of race and ethnicity were heterogenous, and there was some overlap in national datasets used.

CONCLUSION

Overall, racial and ethnic disparities existed in the mortality of pediatric patients with CHD across a variety of mortality types, CHD lesions, and pediatric age ranges. Children of races and ethnicities other than non-Hispanic White generally had increased risk of mortality, with non-Hispanic Black children most consistently having the highest risk of mortality. Further investigation is needed into the underlying mechanisms of these disparities so interventions to reduce inequities in CHD outcomes can be implemented.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Center-level factors associated with shorter length of stay following stage 1 palliation: An analysis of the national pediatric cardiology quality improvement collaborative registry

BACKGROUND

Stage 1 single ventricle palliation (S1P) has the longest length of stay (LOS) of all benchmark congenital heart operations. Center-level factors contributing to prolonged hospitalization are poorly defined.

METHODS

We analyzed data from infants status post S1P included in the National Pediatric Cardiology Quality Improvement Collaborative Phase II registry. Our primary outcome was patient-level LOS with days alive and out of hospital before stage 2 palliation (S2P) used as a balancing measure. We compared patient and center-level characteristics across quartiles for median center LOS, and used multivariable regression to calculate center-level factors associated with LOS after adjusting for case mix.

RESULTS

Of 2,510 infants (65 sites), 2037 (47 sites) met study criteria (61% male, 61% white, 72% hypoplastic left heart syndrome). There was wide intercenter variation in LOS (first quartile centers: median 28 days [IQR 19, 46]; fourth quartile: 62 days [35, 95], P < .001). Mortality prior to S2P did not differ across quartiles. Shorter LOS correlated with more pre-S2P days alive and out of hospital, after accounting for readmissions (correlation coefficient -0.48, P < .001). In multivariable analysis, increased use of Norwood with a right ventricle to pulmonary artery conduit (aOR 2.65 [1.1, 6.37]), shorter bypass time (aOR 0.99 per minute [0.98,1.0]), fewer additional cardiac operations (aOR 0.46 [0.22, 0.93]), and increased use of NG tubes rather than G tubes (aOR 7.03 [1.95, 25.42]) were all associated with shorter LOS centers.

CONCLUSIONS

Modifiable center-level practices may be targets to standardize practice and reduce overall LOS across centers.

Case Report: 5 Cases of Variant Hypoplastic Left Heart Syndrome Diagnosed on Prenatal Fetal Ultrasound

BACKGROUND Hypoplastic left heart syndrome (HLHS) is a complex left-sided obstructive congenital cardiac condition with several variants. This report is of 5 cases with varying morphology of HLHS diagnosed by fetal prenatal ultrasound at the 4-chamber view (4CV) level. CASE REPORT Five cases were referred by obstetrics and gynecology specialists with preliminary information on visible congenital abnormalities in the third trimester. Fetal echocardiography showed that several morphological variants of HLHS were found. The patient in the first case had the most frequently found variant; this variation is usually linked to mitral valve stenosis (MVS). The second case had the characteristic of mitral valve atresia (MVA), and as a consequence, blood flow was not visible in this variant and the left ventricle (LV) was not clear or not adequately visualized by ultrasound. In the third case, the patient suffered from severe MVS and perhaps a small aorta. Uni-atrial conditions were described in the third case. In the fourth case, the patient had a narrow LV, MVA, ventricular septal defect, nearly united atrium, and tricuspid regurgitation. The fifth case was a case of HLHS with congenital diaphragmatic hernia. Further, 4 out of 5 of the cases were associated with widening of the cisterna magna and Dandy Walker syndrome-associated posterior fossa disorder malformations. The overall maternal age was over 35 years old in 4 cases. Karyotyping examination was not performed in all cases. CONCLUSIONS The role of ultrasound is very important in determining the diagnosis and the degree of development of hypoplastic LV. However, visualization at the 4CV level can detect abnormalities found in the LV.

Hospitalisations of children and adults with Hypoplastic Left Heart Syndrome in Texas from 2009 to 2019

INTRODUCTION

Hypoplastic Left Heart Syndrome accounts for a significant proportion of CHD morbidity and mortality, despite improvements in care and improved survival. This study evaluates number of, reasons for, and trends in discharges of patients with hypoplastic left heart syndrome over 11 years in Texas.

METHODS

The Texas Inpatient Discharge Dataset Public Use File captures almost all discharges in Texas and was reviewed from 2009 to 2019. Discharges of patients ≥5 years of age and diagnosis codes for Hypoplastic Left Heart Syndrome were included. The admitting and principle diagnoses were categorised and all discharges were evaluated for procedures performed. Descriptive and univariate statistical analyses were performed.

RESULTS

A total of 1024 discharges were identified with a 16.9% annual increase over the study period. Median length of stay was 4 [IQR: 2-8] and there were 17 (1.7%) in-hospital mortalities with no differences across age groups. Seven (17.1%) discharges of patients 25+ years were uninsured, higher than other age groups (p < 0.001). The most common admitting diagnosis was CHD and 224 (21.9%) of discharges included a procedure, including 23 heart transplants. Discharges occurred from 67 different hospitals with 4 (6.0%) representing 71.4% of all discharges.

CONCLUSIONS

Discharges of Hypoplastic Left Heart Syndrome have increased rapidly, particularly in the older age groups and were spread over a large number of hospitals. Further work is needed to understand the interplay between Hypoplastic Left Heart Syndrome and other conditions and care experiences that occur within the general population, which will become more common as this population ages and grows.

Survival From Birth Until Young Adulthood Among Individuals With Congenital Heart Defects: CH STRONG

BACKGROUND

Limited population-based information is available on long-term survival of US individuals with congenital heart defects (CHDs). Therefore, we assessed patterns in survival from birth until young adulthood (ie, 35 years of age) and associated factors among a population-based sample of US individuals with CHDs.

METHODS

Individuals born between 1980 and 1997 with CHDs identified in 3 US birth defect surveillance systems were linked to death records through 2015 to identify those deceased and the year of their death. Kaplan-Meier survival curves, adjusted risk ratios (aRRs) for infant mortality (ie, death during the first year of life), and Cox proportional hazard ratios for survival after the first year of life (aHRs) were used to estimate the probability of survival and associated factors. Standardized mortality ratios compared infant mortality, >1-year mortality, >10-year mortality, and >20-year mortality among individuals with CHDs with general population estimates.

RESULTS

Among 11 695 individuals with CHDs, the probability of survival to 35 years of age was 81.4% overall, 86.5% among those without co-occurring noncardiac anomalies, and 92.8% among those who survived the first year of life. Characteristics associated with both infant mortality and reduced survival after the first year of life, respectively, included severe CHDs (aRR=4.08; aHR=3.18), genetic syndromes (aRR=1.83; aHR=3.06) or other noncardiac anomalies (aRR=1.54; aHR=2.53), low birth weight (aRR=1.70; aHR=1.29), and Hispanic (aRR=1.27; aHR=1.42) or non-Hispanic Black (aRR=1.43; aHR=1.80) maternal race and ethnicity. Individuals with CHDs had higher infant mortality (standardized mortality ratio=10.17), >1-year mortality (standardized mortality ratio=3.29), and >10-year and >20-year mortality (both standardized mortality ratios ≈1.5) than the general population; however, after excluding those with noncardiac anomalies, >1-year mortality for those with nonsevere CHDs and >10-year and >20-year mortality for those with any CHD were similar to the general population.

CONCLUSIONS

Eight in 10 individuals with CHDs born between1980 and 1997 survived to 35 years of age, with disparities by CHD severity, noncardiac anomalies, birth weight, and maternal race and ethnicity. Among individuals without noncardiac anomalies, those with nonsevere CHDs experienced similar mortality between 1 and 35 years of age as in the general population, and those with any CHD experienced similar mortality between 10 and 35 years of age as in the general population.

Innovations in cell therapy in pediatric diseases: a narrative review

Background and Objective

Stem cell therapy is a regenerative medicine modality that has the potential to decrease morbidity and mortality by promoting tissue regeneration or modulating the inflammatory response. An increase in the number of clinical trials investigating the efficacy and safety of stem cell therapy in pediatric diseases has led to advancements in this field. Currently, multiple sources and types of stem cells have been utilized in the treatment of pediatric diseases. This review aims to inform researchers and clinicians about preclinical and clinical stem cell therapy trials in pediatric patients. We discuss the different types of stem cells and the wide spectrum of stem cell therapy trials for pediatric diseases, with an emphasis on the outcomes and advancements in the field.

Methods

PubMed and clinicaltrials.gov databases were searched on October 28, 2022 using the following Medical Subject Headings (MeSH) terms "stem cell" or "stem cell therapy" with an age filter <18 years. Our search was limited to publications published between 2000 and 2022.

Key Content and Findings

Diverse sources of stem cells have different properties and mechanisms of action, which allow tailored application of stem cells according to the pathophysiology of the disease. Advancements in stem cell therapies for pediatric diseases have led to improvements in clinical outcomes in some pediatric diseases or in quality of life, such therapies represent a potential alternative to the current treatment modalities.

Conclusions

Stem cell therapy in pediatric diseases has shown promising results and outcomes. However, further studies focusing on the implementation and optimal treatment timeframe are needed. An increase in preclinical and clinical trials of stem cell therapy targeting pediatric patients is required to advance our therapeutic applications.

Hypoplastic Left Heart Syndrome: A Review

Hypoplastic left heart syndrome is a rare and poorly understood congenital disorder featuring a univentricular myocardium, invariably resulting in early childhood death if left untreated. The process to palliate this congenital cardiomyopathy is of high complexity and may include invasive interventions in the first week of life. The preferred treatment strategy involves a staged correction with 3 surgical procedures at different points in time. The Norwood procedure is usually performed within the first weeks of life and aims to increase systemic circulation and relieve pulmonary vascular pressure. This procedure is followed by the bidirectional Glenn and the Fontan procedures in later life, which offer to decrease stress in the ventricular chamber. The prognosis of children with this disease has greatly improved in the past decades; however, it is still largely driven by multiple modifiable and nonmodifiable variables. Novel and clever alternatives have been proposed to improve the survival and neurodevelopment of these patients, although they are not used as standard of care in all centers. The neurodevelopmental outcomes among these patients have received particular attention in the last decade in light to improve this very limiting associated comorbidity that compromises quality of life.

Normothermic Versus Hypothermic Norwood Procedure

BACKGROUND

Either deep hypothermia with circulatory arrest or hypothermic perfusion with antegrade selective cerebral perfusion is used during the Norwood procedure for hypoplastic left heart syndrome. Normothermic perfusion has been described for pediatric patients. The aim of this study was to compare the early outcomes of patients undergoing the Norwood procedure with antegrade selective cerebral perfusion under hypothermia with the procedure under normothermia.

METHODS

From 2005 to 2020, 117 consecutive patients with hypoplastic left heart syndrome underwent the Norwood procedure: 68 (58.2%) under hypothermia and 49 (41.8%) under normothermia. Antegrade selective cerebral perfusion flow was adjusted to maintain right radial arterial pressure above 50 mm Hg, and a flow rate of 40 to 50 mL kg^-1 min^-1. Baseline characteristics, operative data, and postoperative outcomes including lactate recovery time were compared.

RESULTS

The baseline characteristics and cardiovascular diagnosis were similar in both groups. The normothermic group had a significantly shorter bypass time (in minutes) of 90.31 (±31.60) versus 123.63 (±25.33), a cross-clamp time of 45.24 (±16.35) versus 81.93 (±16.34), and an antegrade selective cerebral perfusion time of 25.61 (±13.84) versus 47.30 (±14.35) (P < .001). There were no statistically significant differences in the immediate postoperative course, or in terms of in-hospital mortality, which totaled 9 (18.4%) in the normothermic group, and 10 (14.9%) in the hypothermic group (P = .81).

CONCLUSION

The normothermic Norwood procedure with selective cerebral perfusion is feasible and safe in terms of in-hospital mortality and short-term outcomes. It is comparable to the standard hypothermic Norwood with selective cerebral perfusion.

Left-Sided Heart Defects and Laterality Disturbance in Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a complex congenital heart disease characterized by hypoplasia of left-sided heart structures. The developmental basis for restriction of defects to the left side of the heart in HLHS remains unexplained. The observed clinical co-occurrence of rare organ situs defects such as biliary atresia, gut malrotation, or heterotaxy with HLHS would suggest possible laterality disturbance. Consistent with this, pathogenic variants in genes regulating left-right patterning have been observed in HLHS patients. Additionally, Ohia HLHS mutant mice show splenic defects, a phenotype associated with heterotaxy, and HLHS in Ohia mice arises in part from mutation in Sap130, a component of the Sin3A chromatin complex known to regulate Lefty1 and Snai1, genes essential for left-right patterning. Together, these findings point to laterality disturbance mediating the left-sided heart defects associated with HLHS. As laterality disturbance is also observed for other CHD, this suggests that heart development integration with left-right patterning may help to establish the left-right asymmetry of the cardiovascular system essential for efficient blood oxygenation.

Heart Disease and Stroke Statistics-2023 Update: A Report From the American Heart Association

BACKGROUND

The American Heart Association, in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, diet, and weight) and health factors (cholesterol, blood pressure, and glucose control) that contribute to cardiovascular health. The Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, congenital heart disease, rhythm disorders, subclinical atherosclerosis, coronary heart disease, heart failure, valvular disease, venous disease, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The American Heart Association, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2023 Statistical Update is the product of a full year's worth of effort in 2022 by dedicated volunteer clinicians and scientists, committed government professionals, and American Heart Association staff members. The American Heart Association strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional COVID-19 (coronavirus disease 2019) publications, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Early Mortality in Infants Born with Neonatally Operated Congenital Heart Defects and Low or Very-Low Birthweight: A Systematic Review and Meta-Analysis

Mortality outcomes of children with isolated neonatally operated congenital heart defects (CHDs) born with a low (LBW), moderately low (MLBW) or very-low birthweight (VLBW) remain ambiguous. We searched Medline and Embase (inception until October 2021) and included studies that evaluated early mortality. The risk of bias was assessed using the Critical Appraisal Skills Program cohort checklist. Meta-analysis involved random-effects models. We explored variability in mortality across birthweight subgroups, CHD types, and study designs. From 2035 reports, we included 23 studies in qualitative synthesis, and the meta-analysis included 11 studies (1658 CHD cases), divided into 30 subcohorts. The risk of bias was low in 4/11 studies included in the meta-analysis. Summary mortality before discharge or within one month after surgery was 37% (95%CI 27-47). Early mortality varied by birthweight (VLBW 56%, MLBW 15%, LBW 16%; p = 0.003) and CHD types (hypoplastic left heart syndrome (HLHS) 50%, total anomalous pulmonary venous return (TAPVR) 47%, transposition of the great arteries (TGA) 34%, coarctation of the aorta (CoA) 16%; p = 0.13). Mortality was higher in population-based studies (49% vs. 10%; p = 0.006). One-third of infants born with neonatally operated isolated CHDs and LBW, MLBW, or VLBW died within 30 days after surgery. Mortality varied across infant and study characteristics. These results may help clinicians assess neonatal prognosis. PROSPERO registration CRD42020170289.

Novel rare mutation in a conserved site of PTPRB causes human hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is a rare but fatal birth defect in which the left side of the heart is underdeveloped. HLHS accounts for 2% to 4% of congenital heart anomalies. Whole genome sequencing (WGS) was conducted for a family trio consisting of a proband and his parents. A homozygous rare variant was detected in the PTPRB (Protein Tyrosine Phosphatase Receptor Type B) gene of the proband by functional annotation and co-segregation analysis. Sanger sequencing was used to confirm genotypes of the variant. The in silico prediction tools, including Mutation Taster, SpliceAI, and CADD, were used to predict the impact of the mutation. The allele frequencies across populations were compared based on multiple databases, including "1000 genomes" and "gnomAD". We used two vectors (pcMINI and pcDNA3.1) to generate a minigene construct to validate the mutational effect at the transcriptional level. Family-based WGS analyses showed that only a homozygous splice acceptor variant (NC_000012.12: g.70636068T>G, NM_001109754.4: c.56-2A>C, NG_029940.2: g.6373A>C) at the exon-intron border of PTPRB gene associates with HLHS. This variant is also within the region with the enhancer activity based on UCSC genome annotation. Genotyping and Sanger sequencing revealed that the proband's parents are heterozygous for this variant. Evolutionary conservation analysis revealed that the site (NC_000012.12: g.70636068) is extremely conserved across species, supporting the evolutionary functional constraints of the ancestral wild type (T). In silico tools universally predicted a deleterious or disease-causing impact of the mutation from T to G. The mutation was not found in the 1000 genomes and gnomAD databases, which indicates that this mutation is very rare in most human populations. A splicing assay indicated that the mutated minigene caused aberrant splicing of mRNA, in which a 3 bp missing in the second exon resulted in the deletion of one amino acid (NP_001103224.1:p.Glu19del) compared to the normal protein of PRPTB (also the VE-PTP). Structure prediction revealed that the deletion occurred within the C-region of the signal peptide of VE-PTP, suggesting signal peptide-related defects as a potential mechanism for the HLHS cellular pathogeny. We report a rare homozygous variant with splicing error in PTPRB associated with HLHS. Previous model species studies revealed conserved functions of PTPRB in cardiovascular and heart development in mice and zebrafish. Our study is the first report to show the association between PTPRB and HLHS in humans.

Preterm Birth Is Associated With Adverse Cardiac Remodeling and Worse Outcomes in Patients With a Functional Single Right Ventricle

OBJECTIVE

To assess the effects of preterm birth on cardiac structure and function and transplant-free survival in patients with hypoplastic left heart syndrome and associated anomalies throughout the staged palliation process.

STUDY DESIGN

Data from the Single Ventricle Reconstruction trial were used to assess the impact of prematurity on echocardiographic measures at birth, Norwood, Stage II, and 14 months in 549 patients with a single functional right ventricle. Medical history was recorded once a year using medical records or telephone interviews. Cox regression models were applied to analyze transplant-free survival to age 6 years. Causal mediation analysis was performed to estimate the mediating effect of birth weight within this relationship.

RESULTS

Of the 549 participants, 64 (11.7%) were born preterm. Preterm-born participants had lower indexed right ventricle end-diastolic volumes at birth but higher volumes than term-born participants by age 14 months. Preterm-born participants had an increased risk of death or heart transplantation from birth to age 6 years, with an almost linear increase in the observed risk as gestational age decreased below 37 weeks. Of the total effect of preterm birth on transplant-free survival, 27.3% (95% CI 2.5-59.0%) was mediated through birth weight.

CONCLUSIONS

Preterm birth is associated with adverse right ventricle remodeling and worse transplant-free survival throughout the palliation process, in part independently of low birth weight. Further investigation into this vulnerable group may allow development of strategies that mitigate the impact of prematurity on outcomes in patients with hypoplastic left heart syndrome.

Pediatric Heart Failure Inpatient Mortality: A Cross-Sectional Analysis

Background

Heart failure constitutes significant morbidity and mortality among the pediatric population. Few data exist on the prevalence and mortality rate of pediatric heart failure (pHF) in the United States.

Objectives

This study aimed to determine the in-hospital mortality and the principal diagnoses in pediatric patients with heart failure who died while being hospitalized in the United States.

Methods

This is a retrospective cross-sectional study using data from the 2019 Kid Inpatient Database (KID). The KID contained data on hospitalized children below 21 years of age. Using Stata 17 software (StataCorp LLC, College Station, Texas), the data were searched for heart failure diagnoses using International Classification of Diseases 10th revision Clinical Modification (ICD-10-CM) codes. By using the “rank” command in Stata, the most common principal diagnoses were placed in descending order of frequency, and these were further divided into different ICD-10 code categories.

Results

There were 16,206 pHF admissions in 2019. Of these admissions, 1,023 (6.31%) patients died. The top five principal ICD 10 code categories among all pHF deaths in descending order were circulatory system (17.95%), congenital/chromosomal abnormalities (17.43%), respiratory system (10.28%), infectious diseases (9.24%, and perinatal diseases (7.90%). Among all pHF deaths, sepsis of unspecified organisms (5.14%), hypoplastic left heart syndrome (HLHS) (3.19%), and acute respiratory failure with hypoxia (3.14%) were the most common primary diagnoses.

Conclusion and significance

Pediatric heart failure in-hospital overall mortality is 6.31%, and sepsis of unspecified organisms, HLHS, and acute respiratory failure are the most common principal diagnoses among these children. Preventive measures and prompt treatment of infections are paramount to reducing pHF mortality.

Medical Therapies for Heart Failure in Hypoplastic Left Heart Syndrome

Significant surgical and medical advances over the past several decades have resulted in a growing number of infants and children surviving with hypoplastic left heart syndrome (HLHS) and other congenital heart defects associated with a single systemic right ventricle (RV). However, cardiac dysfunction and ultimately heart failure (HF) remain the most common cause of death and indication for transplantation in this population. Moreover, while early recognition and treatment of single ventricle-related complications are essential to improving outcomes, there are no proven therapeutic strategies for single systemic RV HF in the pediatric population. Importantly, prototypical adult HF therapies have been relatively ineffective in mitigating the need for cardiac transplantation in HLHS, likely due to several unique attributes of the failing HLHS myocardium. Here, we discuss the most commonly used medical therapies for the treatment of HF symptoms in HLHS and other single systemic RV patients. Additionally, we provide an overview of potential novel therapies for systemic ventricular failure in the HLHS and related populations based on fundamental science, pre-clinical, clinical, and observational studies in the current literature.

Flow-Mediated Factors in the Pathogenesis of Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a life-threatening congenital heart disease that is characterized by severe underdevelopment of left heart structures. Currently, there is no cure, and affected individuals require surgical palliation or cardiac transplantation to survive. Despite these resource-intensive measures, only about half of individuals reach adulthood, often with significant comorbidities such as liver disease and neurodevelopmental disorders. A major barrier in developing effective treatments is that the etiology of HLHS is largely unknown. Here, we discuss how intracardiac blood flow disturbances are an important causal factor in the pathogenesis of impaired left heart growth. Specifically, we highlight results from a recently developed mouse model in which surgically reducing blood flow through the mitral valve after cardiogenesis led to the development of HLHS. In addition, we discuss the role of interventional procedures that are based on improving blood flow through the left heart, such as fetal aortic valvuloplasty. Lastly, using the surgically-induced mouse model, we suggest investigations that can be undertaken to identify the currently unknown biological pathways in left heart growth failure and their associated therapeutic targets.

Surgical Strategies in Single Ventricle Management of Neonates and Infants

No area of congenital heart disease has undergone greater change and innovation than Single Ventricle management over the past 20 years. Surgical and catheter lab interventions have transformed outcomes such that in some subgroups more than 80% of these patients can survive into adulthood. Driven by parallel development in diagnostic imaging and cardiac intensive care, surgical management is focused on the neonatal period as the key time to creating a balanced circulation and limiting pulmonary blood-flow. Different configurations of the circulation including new types of surgical shunts and the role of 'hybrid' circulations provide greater options and better physiology. This overview will focus on these changes in surgical management and timing but also look at the exciting areas of regenerative therapies to improve ventricular function, and the concept of ventricular rehabilitation to achieve biventricular circulations in certain groups of patients. The importance of early (neonatal) intervention and multidisciplinary approach to management is emphasised, as well as looking beyond simply survival but also improving neurodevelopmental outcomes.

Distance from home to birth hospital, transfer, and mortality in neonates with hypoplastic left heart syndrome in California

BACKGROUND

Prior studies report a lower risk of mortality among neonates with hypoplastic left heart syndrome (HLHS) who are born at a cardiac surgical center, but many neonates with HLHS are born elsewhere and transferred for repair. We investigated the associations between the distance from maternal home to birth hospital, the need for transfer after birth, sociodemographic factors, and mortality in infants with HLHS in California from 2006 to 2011.

METHODS

We used linked data from two statewide databases to identify neonates for this study. Three groups were included in the analysis: "lived close/not transferred," "lived close/transferred," and "lived far/not transferred." We defined "lived close" versus "lived far" as 11 miles, the median distance from maternal residence to birth hospital. Log-binomial regression models were used to identify the association between sociodemographic variables, distance to birth hospital and transfer. Cox proportional hazards models were used to identify the association between mortality and distance to birth hospital and transfer. Models were adjusted for sociodemographic variables.

RESULTS

Infants in the lived close/not transferred and the lived close/transferred groups (vs. the lived far/not transferred group) were more likely to live in census tracts above the 75th percentile for poverty with relative risks 1.94 (95% confidence interval [CI] 1.41-2.68) and 1.21 (95% CI 1.05-1.40), respectively. Neonatal mortality was higher among the lived close/not transferred group compared with the lived far/not transferred group (hazard ratio 1.77, 95% CI 1.17-2.67).

CONCLUSIONS

Infants born to mothers experiencing poverty were more likely to be born close to home. Infants with HLHS who were born close to home and not transferred to a cardiac center had a higher risk of neonatal mortality than infants who were delivered far from home and not transferred. Future studies should identify the barriers to delivery at a cardiac center for mothers experiencing poverty.

Serial Assessment of Right Ventricular Deformation in Patients With Hypoplastic Left Heart Syndrome: A Cardiovascular Magnetic Resonance Feature Tracking Study

Background As right ventricular dysfunction is a major cause of adverse outcome in patients with hypoplastic left heart syndrome, the aim was to assess right ventricular function and deformation after Fontan completion by performing 2-dimensional cardiovascular magnetic resonance feature tracking in serial cardiovascular magnetic resonance studies. Methods and Results Cardiovascular magnetic resonance examinations of 108 patients with hypoplastic left heart syndrome (female: 31) were analyzed. Short-axis cine images were used for right ventricular volumetry. Two-dimensional cardiovascular magnetic resonance feature tracking was performed using long-axis and short-axis cine images to measure myocardial global longitudinal, circumferential, and radial strain. All patients had at least 2 cardiovascular magnetic resonance examinations after Fontan completion and 41 patients had 3 examinations. Global strain values and right ventricular ejection fraction decreased from the first to the third examination with a significant decline in global longitudinal strain from the first examination to the second examination (median, first, and third quartile: -18.8%, [-20.5;-16.5] versus -16.9%, [-19.3;-14.7]) and from the first to the third examination in 41 patients (-18.6%, [-20.9;-15.7] versus -15.8%, [-18.7;-12.6]; P-values <0.004). Right ventricular ejection fraction decreased significantly from the first to the third examination (55.4%, [49.8;59.3] versus 50.2%, [45.0;55.9]; P<0.002) and from the second to the third examination (53.8%, [47.2;58.7] versus 50.2%, [45.0;55.9]; P<0.0002). Conclusions Serial assessment of cardiovascular magnetic resonance studies in patients with hypoplastic left heart syndrome after Fontan completion demonstrates a significant reduction in global strain values and right ventricular ejection fraction at follow-up. The significant reduction in global longitudinal strain between the first 2 examinations with non-significant changes in right ventricular ejection fraction suggest that global longitudinal strain measured by 2-dimensional cardiovascular magnetic resonance feature tracking might be a superior technique for the detection of changes in myocardial function.

Novel Protein-Protein Interactions Highlighting the Crosstalk between Hypoplastic Left Heart Syndrome, Ciliopathies and Neurodevelopmental Delays

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) affecting 1 in 5000 newborns. We constructed the interactome of 74 HLHS-associated genes identified from a large-scale mouse mutagenesis screen, augmenting it with 408 novel protein-protein interactions (PPIs) using our High-Precision Protein-Protein Interaction Prediction (HiPPIP) model. The interactome is available on a webserver with advanced search capabilities. A total of 364 genes including 73 novel interactors were differentially regulated in tissue/iPSC-derived cardiomyocytes of HLHS patients. Novel PPIs facilitated the identification of TOR signaling and endoplasmic reticulum stress modules. We found that 60.5% of the interactome consisted of housekeeping genes that may harbor large-effect mutations and drive HLHS etiology but show limited transmission. Network proximity of diabetes, Alzheimer's disease, and liver carcinoma-associated genes to HLHS genes suggested a mechanistic basis for their comorbidity with HLHS. Interactome genes showed tissue-specificity for sites of extracardiac anomalies (placenta, liver and brain). The HLHS interactome shared significant overlaps with the interactomes of ciliopathy- and microcephaly-associated genes, with the shared genes enriched for genes involved in intellectual disability and/or developmental delay, and neuronal death pathways, respectively. This supported the increased burden of ciliopathy variants and prevalence of neurological abnormalities observed among HLHS patients with developmental delay and microcephaly, respectively.

Social Determinants of Disparities in Mortality Outcomes in Congenital Heart Disease: A Systematic Review and Meta-Analysis

Background

Social determinants of health (SDoH) affect congenital heart disease (CHD) mortality across all forms and age groups. We sought to evaluate risk of mortality from specific SDoH stratified across CHD to guide interventions to alleviate this risk.

Methods

We searched electronic databases between January 1980 and June 2019 and included studies that evaluated occurrence of CHD deaths and SDoH in English articles. Meta-analysis was performed if SDoH data were available in &gt;3 studies. We included race/ethnicity, deprivation, insurance status, maternal age, maternal education, single/multiple pregnancy, hospital volume, and geographic location of patients as SDoH. Data were pooled using random-effects model and outcome was reported as odds ratio (OR) with 95% confidence interval (CI).

Results

Of 17,716 citations reviewed, 65 met inclusion criteria. Sixty-three were observational retrospective studies and two prospective. Of 546,981 patients, 34,080 died. Black patients with non-critical CHD in the first year of life (Odds Ratio 1.62 [95% confidence interval 1.47–1.79], I2 = 7.1%), with critical CHD as neonates (OR 1.27 [CI 1.05-1.55], I2 = 0%) and in the first year (OR 1.68, [1.45-1.95], I2 = 0.3%) had increased mortality. Deprived patients, multiple pregnancies, patients born to mothers &lt;18 years and with education &lt;12 years, and patients on public insurance with critical CHD have greater likelihood of death after the neonatal period.

Conclusion

This systematic review and meta-analysis found that Black patients with CHD are particularly vulnerable for mortality. Numerous SDoH that affect mortality were identified for specific time points in CHD course that may guide interventions, future research and policy.

Systematic Review Registration

[https://www.crd.york.ac.uk/PROSPERO/display_record.php?ID=CRD42019139466&amp;ID=CRD42019139466], identifier [CRD42019139466].

3D-cardiomics: A spatial transcriptional atlas of the mammalian heart

Understanding the spatial gene expression and regulation in the heart is key to uncovering its developmental and physiological processes, during homeostasis and disease. Numerous techniques exist to gain gene expression and regulation information in organs such as the heart, but few utilize intuitive true-to-life three-dimensional representations to analyze and visualise results. Here we combined transcriptomics with 3D-modelling to interrogate spatial gene expression in the mammalian heart. For this, we microdissected and sequenced transcriptome-wide 18 anatomical sections of the adult mouse heart. Our study has unveiled known and novel genes that display complex spatial expression in the heart sub-compartments. We have also created 3D-cardiomics, an interface for spatial transcriptome analysis and visualization that allows the easy exploration of these data in a 3D model of the heart. 3D-cardiomics is accessible from http://3d-cardiomics.erc.monash.edu/.

Post-operative arrhythmias in patients with hypoplastic left heart syndrome and anatomic variants: incidence, type, and course

BACKGROUND

Arrhythmias are common in the post-operative course of patients with hypoplastic left heart syndrome. We sought to determine the types, incidence, risk factors, and impact of arrhythmias in patients with HLHS and anatomic variants.

METHODS

We performed a retrospective chart review of 120 consecutive patients with HLHS and anatomical variants, who had single-ventricle palliation at our institution from January, 2006 to December, 2016.

RESULTS

A total of thirty-one patients (26%) had 37 episodes of arrhythmias over a median follow-up period of 3.5 years. Of the 37 episodes, 12 (32.4%) were ectopic atrial tachycardia, 9 (24.3%) were paroxysmal supraventricular tachycardia, 4 (10.8%) were junctional ectopic tachycardia, 5 (13.6%) were sinus node dysfunction, 3 (8.1%) were heart block, 2 (5.4%) were atrial flutter, and 2 (5.4%) were ventricular tachycardia. Twenty-four (65%) of the arrhythmias occurred at post-stage 1 surgery. Most (64.8%) of the arrhythmias were resolved. Arrhythmias that occurred at post-stage 1 surgery were more likely to resolve compared to post-stages 2 or 3 (p = 0.006). No anatomical, surgical, or clinical variables were associated with arrhythmia except for age (OR per unit decrease in age at stage 1 palliation: 1.12 (95% CI 1.003, 1.250); p = 0.0439). Arrhythmias were not associated with length of hospital stay or mortality.

CONCLUSION

Arrhythmias are common in patients with HLHS and anatomic variants, with EAT and PSVT being the most common types. Arrhythmias were associated with younger age at surgery, but did not affect mortality or length of hospital stay.

The Improved Prognosis of Hypoplastic Left Heart: A Population-Based Register Study of 343 Cases in England and Wales

Background: Hypoplastic Left Heart Syndrome (HLHS) is a severe congenital heart defect (CHD) characterised by the underdevelopment of the left side of the heart with varying levels of hypoplasia of the left atrium, mitral valve, left ventricle, aortic valve and aortic arch. In the UK, age 12 survival for cases born between 1991 and 1993 was 21%. UK survival estimates corresponding to cases born between 2000 and 2015 were improved at 56%, but survival was examined up to age five only. Contemporary long-term survival estimates play a crucial role in counselling parents following diagnosis. The aim of this study was to report survival estimates up to age 15 for children born with HLHS or hypoplastic left ventricle with additional CHD in England and Wales between 1998 and 2012. Methods: Cases of HLHS notified to four congenital anomaly registers in England and Wales during 1998-2012, matched to Office for National Statistics mortality information, were included. Kaplan-Meier survival estimates to age 15 were reported. Cox regression models were fitted to examine risk factors for mortality. Results: There were 244 cases of HLHS and 99 cases of hypoplastic left ventricle co-occurring with other CHD, with traced survival status. Kaplan-Meier survival estimates for HLHS were 84.4% at age 1 week, 76.2% at 1 month, 63.5% at age 1 year, 58.6% at age 5 years, 54.6% at age 10 years, and 32.6% to age 15 years. The Kaplan-Meier survival estimates for cases of hypoplastic left ventricle co-occurring with additional CHD were 90.9% at age 1 week, 84.9% at 1 month, 73.7% at age 1 year, 67.7% to age 5 years, 59.2% to age 10 years, and 40.3% to age 15 years. Preterm birth (p = 0.007), low birth weight (p = 0.005), and female sex (p = 0.01) were associated with mortality. Conclusions: We have shown that prognosis associated with HLHS in the twenty first century exceeds that of many previous population-based studies, likely due to improvements in intensive care technologies and advances in surgical techniques over the last few decades.

Associations Between Socioeconomic Context and Congenital Heart Disease Related Outcomes in Adolescents and Adults

Little is known about the relation between socioeconomic factors and health outcomes in adults and adolescents with congenital heart defects (CHD). Population-level data from the Colorado CHD surveillance system from 2011 to 2013 was used to examine the association between area deprivation and outcomes including hospitalizations, emergency department visits, cardiac procedures, all-cause and cardiac-related mortality, and major adverse cardiac events. Socioeconomic context was measured by the Area Deprivation Index at census tract level. Missing race/ethnicity was imputed using the Bayesian Improved Surname Geocoding algorithm. Generalized linear models were utilized to examine health disparities across deprivation quintiles after adjusting for insurance type, race/ethnicity, age, gender, urbanicity, and CHD severity in 5,748 patients. Cases residing in the most deprived quintile had 51% higher odds of inpatient admission, 74% higher odds of emergency department visit, 41% higher odds of cardiac surgeries, and 45% higher odds of major adverse cardiac events compared with cases in the least deprived quintile. Further, rates of hospitalizations, emergency department admissions, and cardiac surgeries were elevated in the most deprived compared with the least deprived quintile. Mortality was not significantly different across quintiles. In conclusion, findings suggest significant health equity issues for adolescent and adults with CHD based on area-based deprivation.

Social determinants of health and outcomes for children and adults with congenital heart disease: a systematic review

BACKGROUND

Social determinants of health (SDH) can substantially impact health outcomes. A systematic review, however, has never been conducted on associations of SDH with congenital heart disease (CHD) outcomes. The aim, therefore, was to conduct such a systematic review.

METHODS

Seven databases were searched through May 2020 to identify articles on SDH associations with CHD. SDH examined included poverty, uninsurance, housing instability, parental educational attainment, immigration status, food insecurity, and transportation barriers. Studies were independently selected and coded by two researchers based on the PICO statement.

RESULTS

The search generated 3992 citations; 88 were included in the final database. SDH were significantly associated with a lower likelihood of fetal CHD diagnosis, higher CHD incidence and prevalence, increased infant mortality, adverse post-surgical outcomes (including hospital readmission and death), decreased healthcare access (including missed appointments, no shows, and loss to follow-up), impaired neurodevelopmental outcomes (including IQ and school performance) and quality of life, and adverse outcomes for adults with CHD (including endocarditis, hospitalization, and death).

CONCLUSIONS

SDH are associated with a wide range of adverse outcomes for fetuses, children, and adults with CHD. SDH screening and referral to appropriate services has the potential to improve outcomes for CHD patients across the lifespan.

IMPACT

Social determinants of health (SDH) are associated with a wide range of adverse outcomes for fetuses, children, and adults with congenital heart disease (CHD). This is the first systematic review (to our knowledge) on associations of SDH with congenital heart disease CHD outcomes. SDH screening and referral to appropriate services has the potential to improve outcomes for CHD patients across the lifespan.

Timing of Transfer and Mortality in Neonates with Hypoplastic Left Heart Syndrome in California

Maternal race/ethnicity is associated with mortality in neonates with hypoplastic left heart syndrome (HLHS). We investigated whether maternal race/ethnicity and other sociodemographic factors affect timing of transfer after birth and whether timing of transfer impacts mortality in infants with HLHS. We linked two statewide databases, the California Perinatal Quality Care Collaborative and records from the Office of Statewide Health Planning and Development, to identify cases of HLHS born between 1/1/06 and 12/31/11. Cases were divided into three groups: birth at destination hospital, transfer on day of life 0-1 ("early transfer"), or transfer on day of life ≥ 2 ("late transfer"). We used log-binomial regression models to estimate relative risks (RR) for timing of transfer and Cox proportional hazard models to estimate hazard ratios (HR) for mortality. We excluded infants who died within 60 days of life without intervention from the main analyses of timing of transfer, since intervention may not have been planned in these infants. Of 556 cases, 107 died without intervention (19%) and another 52 (9%) died within 28 days. Of the 449 included in analyses of timing of transfer, 28% were born at the destination hospital, 49% were transferred early, and 23% were transferred late. Late transfer was more likely for infants of low birthweight (RR 1.74) and infants born to US-born Hispanic (RR 1.69) and black (RR 2.45) mothers. Low birthweight (HR 1.50), low 5-min Apgar score (HR 4.69), and the presence of other major congenital anomalies (HR 3.41), but not timing of transfer, predicted neonatal mortality. Late transfer was more likely in neonates born to US-born Hispanic and black mothers but was not associated with higher mortality.

Echocardiographic Identification of Pulmonary Artery Flow Reversal: An Indicator of Adverse Outcomes in Single Ventricle Physiology

Individuals with single ventricle congenital heart disease (CHD) undergo multiple staged surgical palliations. Staged single ventricle palliation with a superior cavopulmonary connection (SCPC) in infancy followed by a Fontan in early childhood relies on passive, unobstructed pulmonary blood flow and normal pulmonary vasculature. We hypothesized that patients with echocardiographic identification of retrograde flow in a branch pulmonary artery (PA) after SCPC or Fontan are at increased risk for adverse outcomes. We conducted a retrospective chart review of patients seen at Children's Wisconsin from 1999 to 2019. Inclusion criteria included a history of single ventricle congenital heart disease and surgical palliation with a superior cavopulmonary connection (SCPC). We created two cohorts based on transthoracic echocardiographic identification of branch PA flow patterns: those with color Doppler-defined pulmonary artery flow reversal (PA reversal cohort) and those with normal anterograde flow (Non-reversal cohort). We identified 21 patients in the PA reversal cohort and 539 patients in the Non-reversal cohort. The PA reversal cohort had increased hospital length of stay after SCPC palliation (p < 0.001) and decreased transplant-free survival (p = 0.032), but there was no difference in overall survival (p = 0.099). There was no difference in hospital length of stay after Fontan (p = 0.17); however, the PA reversal cohort was significantly less likely to progress to Fontan palliation during early childhood (p = 0.005). Echocardiographic color Doppler identification of branch PA flow reversal in patients with single ventricle physiology is a high-risk indicator for adverse short- and long-term outcomes.

Birthweight and all-cause mortality after childhood and adolescent leukemia: a cohort of children with leukemia from Denmark, Norway, Sweden, and Washington State

Background: High birthweight may predispose children to acute lymphoid leukemia, whereas low birthweight is associated with childhood morbidity and mortality. Low and high birthweight have been inconsistently associated with mortality in children with leukemia.Material and methods: In a cohort of childhood and adolescent leukemia (0-19 years) patients from registries in Denmark, Norway, Sweden, and Washington State in the United States (1967-2015), five-year all-cause mortality was assessed by birthweight and other measures of fetal growth using the cumulative incidence function and Cox regression with adjustment for sex, diagnosis year, country, the presence of Down's syndrome or other malformations, and type of leukemia.Results: Among 7148 children and adolescents with leukemia (55% male), 4.6% were low (<2500 g) and 19% were high (≥4000 g) birthweight. Compared with average weight, hazard ratios (HRs) of death associated with low birthweight varied by age at leukemia diagnosis: 1.5 (95% confidence interval (CI): 0.7, 3.2) for patients 0-1 year old, 1.6 (95% CI: 1.0, 2.6) for >1-2 years old; 1.0 (95% CI: 0.6, 1.5) for 3-8 years old; 1.0 (95% CI: 0.6, 1.8) for 9-13 years old; and 1.2 (95% CI: 0.7, 2.1) for 14-19 years old, and were similar for size for gestational age and Ponderal index. In analyses restricted to children born full term (37-41 weeks of gestation), results were only slightly attenuated but risk was markedly increased for infants aged ≤1 year (HR for low birthweight = 3.2, 95% CI: 1.2, 8.8).Conclusion: This cohort study does not suggest that low birthweight or SGA is associated with increased five-year all-cause mortality risk among children with any type of childhood leukemia or acute lymphoblastic leukemia, specifically, beyond infancy.

Clinical Outcomes and Risk Factors for In-Hospital Mortality in Neonates with Hypoplastic Left Heart Syndrome

The objective of this study was to identify patient and hospitalization characteristics associated with in-hospital mortality in infants with hypoplastic left heart syndrome (HLHS). We conducted a retrospective analysis of a large administrative database, the National Inpatient Sample dataset of the Healthcare Cost and Utilization Project for the years 2002-2016. Neonates with HLHS were identified by ICD-9 and ICD-10 codes. Hospital and patient factors associated with inpatient mortality were analyzed. Overall, 18,867 neonates met the criteria of inclusion; a total of 3813 patients died during the hospitalization (20.2%). In-hospital mortality decreased over the years of the study (27.0% in 2002 vs. 18.3% in 2016). Extracorporeal membrane oxygenation utilization was 8.1%. Univariate and multivariate logistic regression analyses were used to identify risk factors for in-hospital mortality in infants with hypoplastic left heart syndrome. Independent non-modifiable risk factors for mortality were birth weight < 2500 g (Adjusted odds ratio (aOR) 2.16 [1.74-2.69]), gestational age < 37 weeks (aOR 1.73 [1.42-2.10]), chromosomal abnormalities (aOR 3.07 [2.60-3.64]) and renal anomalies (aOR 1.34 [1.10-1.61]). Independent modifiable risk factors for mortality were being transferred-in from another hospital (aOR 1.15 [1.03-1.29]), use of extracorporeal membrane oxygenation (aOR 12.74 [10.91-14.88]). Receiving care in a teaching hospital is a modifiable variable, and it decreased the odds of mortality (aOR 0. 78 [0.64-0.95]). In conclusion, chromosomal anomalies, Extra Corporeal Membrane Oxygenation, gestational age < 37 weeks or birth weight < 2500 g were associated with increased odds of mortality. Modifiable variables as receiving care at birth center and in a hospital designated as a teaching hospital decreased the odds of mortality.

Transplantation-free survival after Norwood surgery for hypoplastic left heart syndrome with aortic atresia: A Swedish national cohort study

BACKGROUND

Norwood surgery has been available in Sweden since 1993. In this national cohort study, we analysed transplantation-free survival after Norwood surgery for hypoplastic left heart syndrome with aortic atresia.

METHODS

Patients were identified from the complete national cohort of live-born with hypoplastic left heart syndrome/aortic atresia 1993-2010. Analysis of survival after surgery was performed using Cox proportional hazards models for the total cohort and for birth period and gender separately. Thirty-day mortality and inter-stage mortality were analysed. Patients were followed until September 2016.

RESULTS

The 1993-2010 cohort consisted of 208 live-born infants. Norwood surgery was performed in 121/208 (58%). The overall transplantation-free survival was 61/121 (50%). The survival was higher in the late period (10-year survival 63%) than in the early period (10-year survival 40%) (p = 0.010) and lower for female (10-year survival 34%) than for male patients (10-year survival 59%) (p = 0.002). Inter-stage mortality between stages I and II decreased from 23 to 8% (p = 0.008). For male patients, low birthweight in relation to gestational age was a factor associated with poor outcome.

CONCLUSION

The survival after Norwood surgery for hypoplastic left heart syndrome/aortic atresia improved by era of surgery, mainly explained by improved survival between stages I and II. Female gender was a significant risk factor for death or transplantation. For male patients, there was an increased risk of death when birthweight was lower than expected in relation to gestational age.

Outcomes of hypoplastic left heart syndrome: analysis of National Inpatient Sample Database 1998-2004 versus 2005-2014

Neonates with hypoplastic left heart syndrome (HLHS) were identified from the National Inpatient Sample dataset for the years 1998-2014. These patients were stratified into two chronological groups, past group (1998-2005) and recent group (2006-2014). A total of 20,649 neonates with HLHS were identified. Of them, 9179 (44.5%) were born in the past group and 11,470 (55.5%) in the recent group. Median birth weight was significantly less in the recent group (2967 g vs. 3110 g, p = 0.005). The patients in the recent group had more patients with low birth weight ( < 2.5 kg) and prematurity (8.7% vs 7.6% and 12.7% vs. 4.3%., respectively). In addition, recent group had more comorbidities including chromosomal anomalies, total anomalous pulmonary venous return, and kidney anomalies (5.6% vs. 3.6%, 2.3% vs. 1.7%, and 5.6% vs. 3.6%, respectively, p < 0.001); these were associated with a higher rate of extracorporeal membrane oxygenation utilization (9.2% vs. 4.5%, p < 0.001). Consequently, median length of stay was longer in the recent group (8 vs. 6 days, p < 0.001).Conclusion: Despite the higher frequency of comorbidities in recent group, the mortality rates decreased by 20% (from 25.3% to 20.6%, p < 0.001). Balloon atrial septostomy was performed less frequently in the recent group (23.3% vs. 16.1%, p < 0.001).What is known:• Hypoplastic left heart syndrome has the highest mortality among congenital cardiac defects during the first year of life.• Limited studies on patients' comorbidities and mortality rates trends over last two decades.What is new:• The study utilized a national database to compare in-hospital mortality and length of stay between the two time periods 1998-2005 and 2006-2014.• The recent group had more comorbidities (prematurity, chromosomal anomalies, total anomalous pulmonary venous return, and kidney anomalies), and there was higher rate of ECMO and longer length of stay, while mortality rates decreased by 20%.

Hypoplastic left heart syndrome: From bedside to bench and back

Hypoplastic Left Heart Syndrome (HLHS) is a complex Congenital Heart Disease (CHD) that was almost universally fatal until the advent of the Norwood operation in 1981. Children with HLHS who largely succumbed to the disease within the first year of life, are now surviving to adulthood. However, this survival is associated with multiple comorbidities and HLHS infants have a higher mortality rate as compared to other non-HLHS single ventricle patients. In this review we (a) discuss current clinical challenges associated in the care of HLHS patients, (b) explore the use of systems biology in understanding the molecular framework of this disease, (c) evaluate induced pluripotent stem cells as a translational model to understand molecular mechanisms and manipulate them to improve outcomes, and (d) investigate cell therapy, gene therapy, and tissue engineering as a potential tool to regenerate hypoplastic cardiac structures and improve outcomes.

Survival After Norwood Procedure in High-Risk Patients

BACKGROUND

Multiple single-ventricle populations are noted to be at increased risk for mortality after the Norwood procedure. Preoperative risk factors include low birth weight, restrictive/intact atrial septum, obstructed pulmonary veins, ventricular dysfunction, and atrioventricular valve regurgitation. We report outcomes of the Norwood procedure in standard- and high-risk patients in the recent era.

METHODS

All patients born with hypoplastic left heart syndrome between 2006 and 2016 who underwent a Norwood procedure at our institution were included. Patient data were retrospectively reviewed, and Kaplan-Meier analysis was used to evaluate survival between groups.

RESULTS

The cohort included 177 patients. Fifty patients were determined high-risk preoperatively: low birth weight (n = 18), ventricular dysfunction/atrioventricular valve regurgitation (n = 13), intact or restrictive atrial septum/obstructed anomalous pulmonary venous return (n = 14), and multiple factors (n = 5). There were 2 (1.6%) deaths before Glenn in the standard-risk group, with a total of 10 (20%) from the high-risk groups (P < .0001). Survival at 1 year differed greatly between groups, with highest being standard risk at 89% and lowest in the intact septum/obstructed veins group at 54%. The difference between groups in long-term survival was significant (P < .001).

CONCLUSIONS

Outcomes after the Norwood procedure have improved for standard-risk patients. Those with preoperative risk factors account for most of the early deaths after the Norwood procedure. This high-risk status does not resolve after Glenn, because longer-term survival continues to diverge from the standard-risk group.

Selective Use of Inpatient Interstage Management After Norwood Procedure

BACKGROUND

We report our intermediate-term results after Norwood procedure, including use of an interstage inpatient management strategy for high-risk patients, and seek to create a predictive model for probability of discharge.

METHODS

A single-site retrospective review was conducted for all patients undergoing Norwood procedure from 2006 to 2016 (N = 177). We compared those discharged home with those who either remained hospitalized until Glenn procedure or died before Norwood procedure discharge. Multivariable logistic regression was used to develop a predictive model for discharge.

RESULTS

During the study period, 120 (68%) patients were discharged home, 45 (25%) remained hospitalized, and 12 (7%) died before Glenn procedure (median age: 71 days). Interstage survival for those discharged after Norwood procedure was 100%. Longitudinal survival for the cohort was 86%, 81%, and 77% at 1, 5, and 10 years, resepectively. Ten-year survival was significantly greater for the discharged group compared with the interstage inpatients (86% vs 56%, P < .001). A reduced predictive model of discharge included lower gestational age (odds ratio [OR]: 0.95), lower median income for ZIP code (OR: 0.4), lower birth-weight-for-age z-score (OR: 0.56), longer cardiopulmonary bypass time (OR: 0.45), and Blalock-Taussig shunt (OR: 0.32).

CONCLUSIONS

Survival up to 10 years after Norwood procedure is good using a strategy of inpatient care for a subset of high-risk patients to mitigate home interstage mortality. A probabilistic model used after Norwood procedure was able to predict interstage discharge with good accuracy, but will require external validation to ensure generalizability. Further work is also needed to determine optimal palliative pathways for the high-risk patients because of the notable attrition beyond successful bidirectional Glenn procedure.

Copy Number Variants of Undetermined Significance Are Not Associated with Worse Clinical Outcomes in Hypoplastic Left Heart Syndrome

OBJECTIVE

To determine the prevalence, spectrum, and prognostic significance of copy number variants of undetermined significance (cnVUS) seen on chromosomal microarray (CMA) in neonates with hypoplastic left heart syndrome (HLHS).

STUDY DESIGN

Neonates with HLHS who presented to Texas Children's Hospital between June 2008 and December 2016 were identified. CMA results were abstracted and compared against copy number variations (CNVs) in ostensibly healthy individuals gathered from the literature. Findings were classified as normal, consistent with a known genetic disorder, or cnVUS. Survival was then compared using Kaplan-Meier analysis. Secondary outcomes included tracheostomy, feeding tube at discharge, cardiac arrest, and extracorporeal membrane oxygenation (ECMO).

RESULTS

Our study cohort comprised 105 neonates with HLHS, including 70 (66.7%) with normal CMA results, 9 (8.6%) with findings consistent with a known genetic disorder, and 26 (24.7%) with a cnVUS. Six of the 26 (23.0%) neonates with a cnVUS had a variant that localized to a specific region of the genome seen in the healthy control population. One-year survival was 84.0% in patients with a cnVUS, 68.3% in those with normal CMA results, and 33.3% in those with a known genetic disorder (P = .003). There were no significant differences in secondary outcomes among the groups, although notably ECMO was used in 15.7% of patients with normal CMA and was not used in those with cnVUS and abnormal results (P = .038).

CONCLUSIONS

Among children with HLHS, cnVUSs detected on CMA are common. The cnVUSs do not localize to specific regions of the genome, and are not associated with worse outcomes compared with normal CMA results.

Accurate Prediction of Congenital Heart Surgical Length of Stay Incorporating a Procedure-Based Categorical Variable

OBJECTIVES

There is increasing demand for the limited resource of Cardiac ICU care. In this setting, there is an expectation to optimize hospital resource use without restricting care delivery. We developed methodology to predict extended cardiac ICU length of stay following surgery for congenital heart disease.

DESIGN

Retrospective analysis by multivariable logistic regression of important predictive factors for outcome of postoperative ICU length of stay greater than 7 days.

SETTING

Cardiac ICU at Boston Children's Hospital, a large, pediatric cardiac surgical referral center.

PATIENTS

All patients undergoing congenital heart surgery at Boston Children's Hospital from January 1, 2010, to December 31, 2015.

INTERVENTIONS

No study interventions.

MEASUREMENTS AND MAIN RESULTS

The patient population was identified. Clinical variables and Congenital Heart Surgical Stay categories were recorded based on surgical intervention performed. A model was built to predict the outcome postoperative ICU length of stay greater than 7 days at the time of surgical intervention. The development cohort included 4,029 cases categorized into five Congenital Heart Surgical Stay categories with a C statistic of 0.78 for the outcome ICU length of stay greater than 7 days. Explanatory value increased with inclusion of patient preoperative status as determined by age, ventilator dependence, and admission status (C statistic = 0.84). A second model was optimized with inclusion of intraoperative factors available at the time of postoperative ICU admission, including cardiopulmonary bypass time and chest left open (C statistic 0.87). Each model was tested in a validation cohort (n = 1,008) with equivalent C statistics.

CONCLUSIONS

Using a model comprised of basic patient characteristics, we developed a robust prediction tool for patients who will remain in the ICU longer than 7 days after cardiac surgery, at the time of postoperative ICU admission. This model may assist in patient counseling, case scheduling, and capacity management. Further examination in external settings is needed to establish generalizability.

Effects of Gestational Age on Early Survivability in Neonates With Hypoplastic Left Heart Syndrome

Prematurity increases pre- and postoperative mortality in children with congenital heart disease. There are no large, multicentered, studies that have evaluated this relation specifically in neonates with hypoplastic left heart syndrome (HLHS). We sought to determine the impact of gestational age (GA) on survival to Stage 1 palliation surgery and hospital discharge in infants with HLHS. We reviewed data from 1,913 neonates with HLHS born at or transferred to a Vermont Oxford Network expanded member hospital in the United States from 2009 to 2014. Demographic, diagnostic, and surgical codes, and outcome data within the Vermont Oxford Network database were used to determine the effect of GA and birth weight on survival to Stage 1 palliation surgery and hospital discharge. Risk models were developed controlling for common confounders to determine the relative risk of GA on the observed outcomes. These data demonstrate that, when compared with 39-week infants, those born at earlier GA were less likely to survive until surgery; <34 weeks adjusted risk ratio (ARR) for survival: 0.47 (95% confidence interval 0.37 to 0.60), 34 to 35 weeks ARR 0.73 (0.62 to 0.87), and 36 to 37 weeks ARR 0.88 (0.83 to 0.94). Higher GA also positively correlated with survival to hospital discharge, although there was no difference in 34 to 35-week infants and 36 to 37-week infants. In conclusion, these data show that GA was an independent risk factor for survival to Stage 1 palliation surgery and survival to hospital discharge. However, there is no significant difference in survival to hospital discharge between infants born in 34 to 37 weeks gestation.

Sociodemographic Factors and Survival of Infants With Congenital Heart Defects

OBJECTIVES

To examine the first-year survival of infants with congenital heart defects (CHDs) and investigate the potential role of socioeconomic and demographic factors on survival.

METHODS

Subjects included 15 533 infants with CHDs born between 2004 and 2013 ascertained by the NC Birth Defects Monitoring Program. We classified CHDs into the following 3 groups: critical univentricular (n = 575), critical biventricular (n = 1494), and noncritical biventricular (n = 13 345). We determined vital status and age at death through linkage to state vital records and used geocoded maternal residence at birth to obtain census information for study subjects. We calculated Kaplan-Meier survival estimates by maternal and infant characteristics and derived hazard ratios from Cox proportional hazard models for selected exposures.

RESULTS

Among all infants with CHDs, there were 1289 deaths (8.3%) in the first year. Among infants with univentricular defects, 61.6% (95% confidence interval [CI]: 57.7%-65.7%) survived. Survival among infants with univentricular defects was considerably better for those whose fathers were ≥35 years old (71.6%; 95% CI: 63.8%-80.3%) compared with those whose fathers were younger (59.7%; 95% CI: 54.6%-65.2%). Factors associated with survival among infants with any biventricular defect included maternal education, race and/or ethnicity, marital status, and delivery at a heart center. The hazard of infant mortality was greatest among non-Hispanic African American mothers.

CONCLUSIONS

Survival among infants with critical univentricular CHDs was less variable across sociodemographic categories compared with survival among infants with biventricular CHDs. Sociodemographic differences in survival among infants with less severe CHDs reinforces the importance of ensuring culturally effective pediatric care for at-risk infants and their families.

EDUCATIONAL SERIES IN CONGENITAL HEART DISEASE: Prenatal diagnosis of congenital heart disease

This review article will guide the reader through the background of prenatal screening for congenital heart disease. The reader will be given insight into the normal screening views, common abnormalities, risk stratification of lesions and also recent advances in prenatal cardiology.

When Parents Refuse: Resolving Entrenched Disagreements Between Parents and Clinicians in Situations of Uncertainty and Complexity

When shared decision making breaks down and parents and medical providers have developed entrenched and conflicting views, ethical frameworks are needed to find a way forward. This article reviews the evolution of thought about the best interest standard and then discusses the advantages of the harm principle (HP) and the zone of parental discretion (ZPD). Applying these frameworks to parental refusals in situations of complexity and uncertainty presents challenges that necessitate concrete substeps to analyze the big picture and identify key questions. I outline and defend a new decision-making tool that includes three parts: identifying the nature of the disagreement, checklists for key elements of the HP and ZPD, and a "think list" of specific questions designed to enhance use of the HP and ZPD in clinical decision making. These tools together will assist those embroiled in complex disagreements to disentangle the issues to find a path to resolution.

Incidence and Outcomes of Patients with Functionally Univentricular Heart Born in Latvia, 2007 to 2015

Background and Objectives: A functionally univentricular heart is the term used to describe congenital heart defects where it is impossible to restore two pumping chambers. These lesions are associated with high mortality, morbidity, and medical resource utilization. The aim of this study was to review incidence and outcomes of patients with a functionally univentricular heart at the only pediatric cardiac surgery center in Latvia. Methods: We performed a retrospective review of medical records of (i) all children with a functionally univentricular heart treated at the Clinic of Pediatric Cardiology and Cardiac Surgery, and (ii) all prenatally diagnosed cases of univentricular heart at Children’s Clinical University Hospital in Latvia. We reviewed data regarding children born from January 1, 2007, to December 31, 2015. The children’s cardiac anatomy and interventions were categorized in accordance with the International Pediatric and Congenital Cardiac Code (v3.3). Results: During the study period, 49 patients with a functionally univentricular heart were admitted to Children’s Clinical University Hospital with a corrected incidence of 0.69 per 1000 live births per year. There were 26 patients that had a hypoplastic left ventricle, and 22 patients that had a hypoplastic right ventricle, while one patient had an indeterminate ventricle. Thirty (61.2%) patients had died by the end of data collection. Twenty-one of the 30 deaths occurred before or immediately after stage I surgical palliation. Cumulative neonatal and 5-year survival of patients with a hypoplastic right ventricle was 81.8% and 63.6%, respectively; for patients with hypoplastic left ventricle—46.2% and 17.3%, respectively. Discussion: This is the first mid-term outcome study of patients with a univentricular heart in Latvia. The high mortality reflects the challenges of a small-volume, developing congenital cardiac surgery center. Data from this study will be used as a baseline for quality improvement.

Prolonged PR Interval at Birth Predicting the High Occurrence of Fatal Atrioventricular Block in Hypoplastic Left Heart Syndrome

Infants with hypoplastic left heart syndrome (HLHS) are at high mortality especially when they are associated with bradyarrhythmias. However, the risk factor of developing high-grade atrioventricular block (HAVB) is still unclear. Seventy-three patients with HLHS in our institutions from 2002 to 2011 were enrolled. The survival rate was assessed by the anatomical types, treatments, occurrence of HAVB, severe tricuspid regurgitation (TR), and restrictive atrial septal defect (ASD) along with electrocardiogram findings at birth. There were 23 (32%) cardiogenic and 7 (10%) non-cardiogenic deaths. The occurrence rate of HAVB but not severe TR or restrictive ASD was higher in 30 deceased patients than in 43 survived patients [7 (23%) vs. 1 (2.3%), p = 0.0038]. The overall mortality rate was higher in patients with HAVB than in those without it (p = 0.0002). Of 7 deceased patients with HAVB, 6 HAVB occurred within 10 days post-surgery, and 3 HAVB led to the early death. The mortality rate of patients with prolonged PR (≥ 0.15 s) but not wide QRS (> 0.08 s) or prolonged QTc (> 0.43 s) at birth was higher than each without it (p = 0.0106). Multivariate analysis indicated that prolonged PR but no other variables was independently associated with the mortality (hazard ratio: 2.948, p = 0.0104). Prolonged PR at birth in HLHS infants predicts the development of fatal HAVB.