Hypoplastic left heart syndrome

SLIT3 deficiency attenuates pressure overload-induced cardiac fibrosis and remodeling

In pulmonary hypertension and certain forms of congenital heart disease, ventricular pressure overload manifests at birth and is an obligate hemodynamic abnormality that stimulates myocardial fibrosis, which leads to ventricular dysfunction and poor clinical outcomes. Thus, an attractive strategy is to attenuate the myocardial fibrosis to help preserve ventricular function. Here, by analyzing RNA-sequencing databases and comparing the transcript and protein levels of fibrillar collagen in WT and global-knockout mice, we found that slit guidance ligand 3 (SLIT3) was present predominantly in fibrillar collagen-producing cells and that SLIT3 deficiency attenuated collagen production in the heart and other nonneuronal tissues. We then performed transverse aortic constriction or pulmonary artery banding to induce left and right ventricular pressure overload, respectively, in WT and knockout mice. We discovered that SLIT3 deficiency abrogated fibrotic and hypertrophic changes and promoted long-term ventricular function and overall survival in both left and right ventricular pressure overload. Furthermore, we found that SLIT3 stimulated fibroblast activity and fibrillar collagen production, which coincided with the transcription and nuclear localization of the mechanotransducer yes-associated protein 1. These results indicate that SLIT3 is important for regulating fibroblast activity and fibrillar collagen synthesis in an autocrine manner, making it a potential therapeutic target for fibrotic diseases, especially myocardial fibrosis and adverse remodeling induced by persistent afterload elevation.

Anesthesia for bilateral pulmonary banding as part of hybrid stage I approach palliating neonates with hypoplastic left heart syndrome

BACKGROUND

Neonatal management of patients with hypoplastic left heart syndrome and complex remains a challenging task, whereby the "hybrid" palliation is often reserved for high-risk patients as a "rescue" procedure.

AIM

This study documents the anesthetic challenges and potential complications associated with the Giessen hybrid stage I approach.

METHODS

The Giessen hybrid stage I approach is focused on surgical bilateral pulmonary artery banding. Retrospective perioperative data were analyzed. Contrary to a stable group A, inotropic treatment before surgery for treatment of postnatal shock classified patients as unstable (Group B). Clinical outcomes considered were inhospital mortality, duration of postoperative mechanical ventilation, postoperative time at the intensive care unit, perioperative vasoactive medication requirements, and red blood cell transfusion.

RESULTS

From June 1998 to December 2015, 185 patients were allocated to Group A (n = 165) and Group B (n = 20). The inhospital mortality was 2.2% with no difference between the groups. There was also no difference in the postoperative time on mechanical ventilation and the time in the intensive care unit. Vasoactive medication was more often required in Group B (100%) compared to Group A (19%). In Group B, more red blood cells were transfused 6.0 ± 8.3 vs 2.0 ± 5.8 mL/kg in Group A (P < .05, 95% CI 0.0 - 2.6).

CONCLUSION

Considering a learning curve, anesthesia for surgical bilateral pulmonary artery banding palliating patients with hypoplastic left heart syndrome and complex can safely be performed, independent from the preoperative clinical status.

Challenges in the handover process of the new-born with congenital heart disease

INTRODUCTION

A new-born with congenital heart disease requires care that involves numerous specialists. Such care can be provided at tertiary referral hospitals and transportation is often needed. A crucial factor is the handover process, when the child is born at a distance, with transfer of both professional responsibility and continued care from one healthcare professional to another.

AIM

The aim of this study was to identify crucial factors for the receiving healthcare professionals that influence the handover process of the new-born with congenital heart disease.

METHOD

A cross-sectional questionnaire study with 53 receiving healthcare professionals at a paediatric intensive care unit at a tertiary referral university hospital in Sweden. The response rate was 48/53. Numerical variables were computed and a content analysis was performed.

FINDINGS

The handover process of the new-born with heart disease transferred to a tertiary referral hospital is complicated. A clear majority of the respondents identified one or more flaws in this process. Crucial factors identified were: relevant and structured information, clear communication, adequate patient knowledge and an enabling environment.

CONCLUSION

A standardised procedure in the different phases of the handover process could improve communication, the working situation for healthcare professionals and thereby increase patient safety.

Changing Epidemiology of Hypoplastic Left Heart Syndrome: Results of a National Swedish Cohort Study

Background Norwood surgery provides a palliative surgical option for hypoplastic left heart syndrome and has been available in Sweden since 1993. The practice of prenatal ultrasound screening was gradually implemented in the same era, resulting in an increased prenatal detection rate. Our primary aims were to study changes in the incidence of live births, prenatal detection rate, and the termination of pregnancies over time. The secondary aims were to study the proportion of live-borns undergoing surgery and to identify factors that influenced whether surgery was or was not performed. Methods and Results Neonates with hypoplastic left heart syndrome with aortic atresia born 1990-2010 were identified through national databases, surgical files, and medical records. The fetal incidence was estimated from the period when prenatal screening was rudimentary. The study period was divided into the presurgical, early surgical, and late surgical periods. The incidence was calculated as the overall yearly incidence for each time period and sex separately. Factors influencing whether surgery was performed were analyzed using Cox-logistic regression. The incidence at live birth decreased from 15.4 to 8.4 per 100 000. The prenatal detection rate increased from 27% to 63%, and terminations increased from 19% to 56%. The odds of having surgery was higher in the late period and higher in the group with prenatal diagnosis. Conclusions We observed a decrease in incidence of live-borns with hypoplastic left heart syndrome aortic atresia. There was in increase in prenatal detection rate and an increase in termination of pregnancy. The proportion of live-borns who underwent surgery increased between time periods.

Three-dimensional and four-dimensional flow assessment in congenital heart disease

Congenital heart disease (CHD) is the most common form of congenital defects, with an incidence of 8 per 1000 births. Due to major advances in diagnostics, perioperative care and surgical techniques, the survival rate of patients with CHD has improved dramatically. Conversely, although 70%-95% of infants with CHD survive into adulthood, the rate of long-term morbidity, which often requires (repeat) intervention, has increased. Recently, the role of altered haemodynamics in cardiac development and CHD has become a subject of interest. Patients with CHD often have abnormal blood flow patterns, either due to the primary cardiac defect or as a consequence of the surgical intervention(s). Research suggests that these abnormal blood flow patterns may contribute to diminished cardiac and vascular function. Serial assessment of haemodynamic parameters in patients with CHD may allow for improved understanding of the often complex haemodynamics in these patients and thereby potentially guide the timing and nature of interventions with the aim of preventing progression of cardiovascular deterioration. In this article we will discuss two novel non-invasive four-dimensional (4D) techniques to evaluate cardiovascular haemodynamics: 4D-flow cardiac magnetic resonance and computational fluid dynamics. This review focuses on the additional value of these two modalities in the evaluation of patients with CHD with abnormal flow patterns, who could benefit from advanced haemodynamic evaluation: patients with coarctation of the aorta, bicuspid aortic valve, tetralogy of Fallot and patients after Fontan palliation.

Impact of High-Risk Characteristics in Hypoplastic Left Heart Syndrome

BACKGROUND

Management of hypoplastic left heart syndrome (HLHS) presents many challenges. We describe our institutional outcomes for management of patients with HLHS over the past 12 years and highlight our strategy for those with highly restrictive/intact interatrial septum (R/I-IAS).

METHODS

Eighty-eight neonates with HLHS underwent surgical treatment, divided equally into Era-I (n = 44, April 2006 to February 2013) and Era-II (n = 44, March 2013 to June 2018). Up to 2013, all patients with R/I-IAS were delivered at an adjacent adult hospital and then moved to our hospital for intensive care and management. From 2014, these patients were delivered at a co-located theatre in our hospital with immediate atrial septectomy. The hybrid approach was occasionally used with preference for the Norwood procedure for suitable candidates.

RESULTS

One-year survival after Norwood procedure was 62.5% and 80% for Era-I and Era-II (P = not significant (ns)), respectively, and 41% of patients were categorized as high risk using conventional criteria. Survival at 1 year differed significantly between high-risk and standard-risk patients (P = 0.01). For high-risk patients, survival increased from 42% to 65% between eras (P = ns). In the R/I-IAS subgroup (n = 15), 11 underwent Norwood procedure after emergency atrial septectomy. Of these, seven born at the adjacent adult hospital had 40% survival to stage II versus 60% for the four born at the colocated theatre. Delivery in a colocated theatre reduced the birth-to-cardiopulmonary bypass median time from 445 (150-660) to 62 (52-71) minutes.

CONCLUSION

Reported surgical outcomes are comparable to multicenter reports and international databases. Proactive management for risk factors such as R/I-IAS may contribute to improved overall outcomes.

Primary Transplantation for Congenital Heart Disease in the Neonatal Period: Long-term Outcomes

BACKGROUND

Primary transplantation was developed in the 1980s as an alternative therapy to palliative reconstruction of uncorrectable congenital heart disease. Although transplantation achieved more favorable results, its utilization has been limited by the availability of donor organs. This review examines the long-term outcomes of heart transplantation in neonates at our institution.

METHODS

The institutional pediatric heart transplant database was queried for all neonatal heart transplants performed between 1985 and 2017. Follow-up was obtained from medical records and an annually administered questionnaire. Overall survival and time to development of complications were estimated using the Kaplan Meier method. Univariate and multivariate analyses were performed to identify independent predictors of survival.

RESULTS

Heart transplantation was performed in 104 neonates. Median age was 17 days. Hypoplastic left heart syndrome (classic or variant) was the primary diagnosis in 77.8% of patients. Survival at 10 years and 25 years was 73.9% and 55.8%, respectively. At 20 years, freedom from allograft vasculopathy and lymphoproliferative disease was 72.0% and 81.9%, respectively. Freedom from re-transplantation was 81.4% at 20 years. Eight patients (7.6%) developed end-stage renal disease. By multivariate analysis, lower glomerular filtration rate and allograft vasculopathy were the only significant predictors of death.

CONCLUSIONS

Neonatal heart transplantation remains a durable therapy with very acceptable long-term survival. Children transplanted in the newborn period have the potential to reach adulthood with minimal need for reintervention.

Early prediction of critical events for infants with single-ventricle physiology in critical care using routinely collected data

OBJECTIVE

Critical events are common and difficult to predict among infants with congenital heart disease and are associated with mortality and long-term sequelae. We aimed to achieve early prediction of critical events, that is, cardiopulmonary resuscitation, emergency endotracheal intubation, and extracorporeal membrane oxygenation in infants with single-ventricle physiology before second-stage surgery. We hypothesized that naïve Bayesian models learned from expert knowledge and clinical data can predict critical events early and accurately.

METHODS

We collected 93 patients with single-ventricle physiology admitted to intensive care units in a single tertiary pediatric hospital between 2014 and 2017. Using knowledge elicited from experienced cardiac-intensive-care-unit providers and machine-learning techniques, we developed and evaluated the Cardiac-intensive-care Warning INdex (C-WIN) system, consisting of a set of naïve Bayesian models that leverage routinely collected data. We evaluated predictive performance using the area under the receiver operating characteristic curve, sensitivity, and specificity. We performed the evaluation at 5 different prediction horizons: 1, 2, 4, 6, and 8 hours before the onset of critical events.

RESULTS

The area under the receiver operating characteristic curves of the C-WIN models ranged between 0.73 and 0.88 at different prediction horizons. At 1 hour before critical events, C-WIN was able to detect events with an area under the receiver operating characteristic curve of 0.88 (95% confidence interval, 0.84-0.92) and a sensitivity of 84% at the 81% specificity level.

CONCLUSIONS

Predictive models may enhance clinicians' ability to identify infants with single-ventricle physiology at high risk of critical events. Early prediction of critical events may indicate the need to perform timely interventions, potentially reducing morbidity, mortality, and health care costs.

Angiotensin converting enzyme inhibitors and interstage failure in infants with hypoplastic left heart syndrome

INTRODUCTION

Angiotensin converting enzyme inhibitors are commonly prescribed medications after the Norwood procedure. There are little data that can be used to determine if angiotensin converting enzyme inhibitors improve interstage outcomes in children with single ventricle defects. The objective of this study was to investigate the relationship between angiotensin converting enzyme inhibitors and interstage failure among infants born with hypoplastic left heart syndrome.

METHODS

We conducted a retrospective cohort study using data from the National Pediatric Cardiology Quality Improvement Collaborative database (collected between 2008 and 2015). We used logistic regression models to assess the exposure-outcome associations and propensity score matching to account for differences in baseline patient characteristics associated with use of angiotensin converting enzyme inhibitors.

RESULTS

A total of 1 487 neonates participated in the study. Thirty-nine percent of patients were prescribed angiotensin converting enzyme inhibitors after the Norwood procedure; 11% experienced interstage failure (death, heart transplantation, and not being a candidate for the second-stage surgery). Before propensity score matching, patients receiving angiotensin converting enzyme inhibitors were significantly more likely to experience interstage failure, compared to patients not on angiotensin converting enzyme inhibitors (OR = 1.44; 95% CI: 1.04, 1.99; P = 0.03). Although there was an increased odds of interstage failure among patients receiving angiotensin converting enzyme inhibitors compared to patients not receiving angiotensin converting enzyme inhibitors in the propensity score-matched cohort, this association was not significantly different (adjusted OR = 1.29; 95% CI: 0.88, 1.95; P = 0.18).

CONCLUSION

Angiotensin converting enzyme inhibitor therapy did not demonstrate a beneficial effect on interstage failure among infants with hypoplastic left heart syndrome, even when patient characteristics associated with the use of angiotensin converting enzyme inhibitors were considered.

Negotiating acceptable termination of pregnancy for non-lethal fetal anomaly: a qualitative study of professional perspectives

OBJECTIVE

This study aims to explore the perspectives of professionals around the issue of termination of pregnancy for non-lethal fetal anomaly (TOPFA).

METHODS

Semi-structured interviews were undertaken with medical professionals (14 consultants in fetal medicine, obstetrics, neonatology and paediatrics) and social care professionals (nine individuals with roles supporting people living with impairment) from the Northeast of England. Analysis adopted an inductive thematic approach facilitated by NVivo.

RESULTS

The overarching theme to emerge from the interview data was of professionals, medical and social care, wanting to present an acceptable self-image of their views on TOPFA. Professionals' values on 'fixing', pain and 'normality' influenced what aspects of moral acceptability they gave priority to in terms of their standpoint and, in turn, their conceptualisations of acceptable TOPFA. Thus, if a termination could be defended morally, including negotiation of several key issues (including 'fixing', perceptions of pain and normality), then participants conceptualised TOPFA as an acceptable pregnancy outcome.

CONCLUSION

Despite different professional experiences, these professional groups were able to negotiate their way through difficult terrain to conceptualise TOPFA as a morally acceptable principle. While professionals have different moral thresholds, no one argued for a restriction of the current legislation. The data suggest that social care professionals also look at the wider social context of a person with an impairment when discussing their views regarding TOPFA. Medical professionals focus more on the individual impairment when discussing their views on TOPFA.

Exploring kinetic energy as a new marker of cardiac function in the single ventricle circulation

Ventricular volumetric ejection fraction (VV EF) is often normal in patients with single ventricle circulations despite them experiencing symptoms related to circulatory failure. We sought to determine if kinetic energy (KE) could be a better marker of ventricular performance. KE was prospectively quantified using four-dimensional flow MRI in 41 patients with a single ventricle circulation (aged 0.5-28 yr) and compared with 43 healthy volunteers (aged 1.5-62 yr) and 14 patients with left ventricular (LV) dysfunction (aged 28-79 yr). Intraventricular end-diastolic blood was tracked through systole and divided into ejected and residual blood components. Two ejection fraction (EF) metrics were devised based on the KE of the ejected component over the total of both the ejected and residual components using 1) instantaneous peak KE to assess KE EF or 2) summating individual peak particle energy (PE) to assess PE EF. KE EF and PE EF had a smaller range than VV EF in healthy subjects (97.9 ± 0.8 vs. 97.3 ± 0.8 vs. 60.1 ± 5.2%). LV dysfunction caused a fall in KE EF ( P = 0.01) and PE EF ( P = 0.0001). VV EF in healthy LVs and single ventricle hearts was equivalent; however, KE EF and PE EF were lower ( P < 0.001) with a wider range indicating a spectrum of severity. Those reporting the greatest symptomatic impairment (New York Heart Association II) had lower PE EF than asymptomatic subjects ( P = 0.0067). KE metrics are markers of healthy cardiac function. PE EF may be useful in grading dysfunction. NEW & NOTEWORTHY Kinetic energy (KE) represents the useful work of the heart in ejecting blood. This article details the utilization of KE indexes to assess cardiac function in health and a variety of pathophysiological conditions. KE ejection fraction and particle energy ejection fraction (PE EF) showed a narrow range in health and a lower wider range in disease representing a spectrum of severity. PE EF was altered by functional status potentially offering the opportunity to grade dysfunction.

Serial changes in anatomy and ventricular function on dual-source cardiac computed tomography after the Norwood procedure for hypoplastic left heart syndrome

BACKGROUND

Accurate evaluation of anatomy and ventricular function after the Norwood procedure in hypoplastic left heart syndrome is important for treatment planning and prognostication, but echocardiography and cardiac MRI have limitations.

OBJECTIVE

To assess serial changes in anatomy and ventricular function on dual-source cardiac CT after the Norwood procedure for hypoplastic left heart syndrome.

MATERIALS AND METHODS

In 14 consecutive patients with hypoplastic left heart syndrome, end-systolic and end-diastolic phase cardiac dual-source CT was performed before and early (average: 1 month) after the Norwood procedure, and repeated late (median: 4.5 months) after the Norwood procedure in six patients. Ventricular functional parameters and indexed morphological measurements including pulmonary artery size, right ventricular free wall thickness, and ascending aorta size on cardiac CT were compared between different time points. Moreover, morphological features including ventricular septal defect, endocardial fibroelastosis and coronary ventricular communication were evaluated on cardiac CT.

RESULTS

Right ventricular function and volumes remained unchanged (indexed end-systolic and end-diastolic volumes: 38.9±14.0 vs. 41.1±21.5 ml/m², P=0.7 and 99.5±30.5 vs. 105.1±33.0 ml/m², P=0.6; ejection fraction: 60.1±7.3 vs. 63.8±7.0%, P=0.1, and indexed stroke volume: 60.7±18.0 vs. 64.0±15.6 ml/m², P=0.5) early after the Norwood procedure, but function was decreased (ejection fraction: 64.2±2.6 vs. 58.1±7.1%, P=0.01) and volume was increased (indexed end-systolic and end-diastolic volumes: 39.2±14.9 vs. 68.9±20.6 ml/m², P<0.003 and 107.8±36.5 vs. 162.9±36.2 ml/m², P<0.006, and indexed stroke volume: 68.6±21.7 vs. 94.0±21.3 ml/m², P=0.02) later. Branch pulmonary artery size showed a gradual decrease without asymmetry after the Norwood procedure. Right and left pulmonary artery stenoses were identified in 21.4% (3/14) of the patients. Indexed right ventricular free wall thickness showed a significant increase early after the Norwood procedure (25.5±3.5 vs. 34.8±5.1 mm/m², P=0.01) and then a significant decrease late after the Norwood procedure (34.8±5.1 vs. 27.2±4.2 mm/m², P<0.0001). The hypoplastic ascending aorta smaller than 2 mm in diameter was identified in 21.4% (3/14) of the patients. Ventricular septal defect (n=3), endocardial fibroelastosis (n=2) and coronary ventricular communication (n=1) were detected on cardiac CT.

CONCLUSION

Cardiac CT can be used to assess serial changes in anatomy and ventricular function after the Norwood procedure in patients with hypoplastic left heart syndrome.

Extubation Failure Is Associated With Increased Mortality Following First Stage Single Ventricle Reconstruction Operation

OBJECTIVES

To identify the prevalence, causes, risk factors, and outcomes associated with extubation failure following first stage single ventricle reconstruction surgery.

DESIGN

Retrospective cohort analysis of neonates who underwent a first stage single ventricle reconstruction operation. Extubation failure was defined as endotracheal reintubation within 48 hours of first extubation attempt.

SETTING

The Royal Children's Hospital, Melbourne.

PATIENTS

Data were collected for all infants who underwent a Norwood or Damus-Kaye-Stansel procedure between 2005 and 2014 at our institution.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Extubation failure occurred in 23 of 137 neonates (16.8%; 95% CI, 11.0-24.1%) who underwent a trial of extubation. Overall, 42 patients (30.7%) were extubated to room air, 88 (64.2%) to nasal continuous positive airway pressure, and seven (5.1%) to high-flow nasal cannulae, though there was no major difference in extubation failure rates between these three groups (p = 0.37). The median time to reintubation was 16.7 hours (interquartile range, 3.2-35.2), and male infants failed extubation more frequently (63.2% vs 87.0%; p = 0.02), although age, gestation, weight, cardiac diagnosis (hypoplastic left heart syndrome vs other single ventricle conditions), shunt type (modified Blalock-Taussig vs right ventricle-pulmonary artery shunt), intraoperative perfusion times, preextubation mechanical ventilation duration, preextubation acid-base status, and postoperative fluid balance were not related to extubation outcome. Infants who failed extubation had a higher intensive care mortality (19.4% vs 3.5%; p = 0.03) and in-hospital mortality (30.4% vs 6.1%; p < 0.001).

CONCLUSIONS

There is a high prevalence of extubation failure following first stage single ventricle reconstruction, and this is associated with considerably worse patient outcomes. The high prevalence and also the wide variation in rates of extubation failure in reported literature provide with an opportunity for implementation of quality assurance activities to minimize this complication and improve outcomes.

Induced pluripotent stem cell modelling of HLHS underlines the contribution of dysfunctional NOTCH signalling to impaired cardiogenesis

Hypoplastic left heart syndrome (HLHS) is among the most severe forms of congenital heart disease. Although the consensus view is that reduced flow through the left heart during development is a key factor in the development of the condition, the molecular mechanisms leading to hypoplasia of left heart structures are unknown. We have generated induced pluripotent stem cells (iPSC) from five HLHS patients and two unaffected controls, differentiated these to cardiomyocytes and identified reproducible in vitro cellular and functional correlates of the HLHS phenotype. Our data indicate that HLHS-iPSC have a reduced ability to give rise to mesodermal, cardiac progenitors and mature cardiomyocytes and an enhanced ability to differentiate to smooth muscle cells. HLHS-iPSC-derived cardiomyocytes are characterised by a lower beating rate, disorganised sarcomeres and sarcoplasmic reticulum and a blunted response to isoprenaline. Whole exome sequencing of HLHS fibroblasts identified deleterious variants in NOTCH receptors and other genes involved in the NOTCH signalling pathway. Our data indicate that the expression of NOTCH receptors was significantly downregulated in HLHS-iPSC-derived cardiomyocytes alongside NOTCH target genes confirming downregulation of NOTCH signalling activity. Activation of NOTCH signalling via addition of Jagged peptide ligand during the differentiation of HLHS-iPSC restored their cardiomyocyte differentiation capacity and beating rate and suppressed the smooth muscle cell formation. Together, our data provide firm evidence for involvement of NOTCH signalling in HLHS pathogenesis, reveal novel genetic insights important for HLHS pathology and shed new insights into the role of this pathway during human cardiac development.

Parents' Experiences of Having a Baby With a Congenital Heart Defect and the Child's Heart Surgery

The incidence of children born with congenital heart disease is 1%. Congenital heart disease is among the birth defects that lead to the longest hospital stays, and children with congenital heart disease often require frequent hospitalization and several heart operations, along with lifelong follow-up visits. This study aims to describe parents' experiences when their child has a heart defect and undergoes open heart surgery. A total of 10 parents were interviewed: 8 mothers and 2 fathers. The interviews took place 2 years after the heart surgery. The interviews were analyzed using a content analysis method, which resulted in 4 categories: maintaining belief, experiencing the surgery as a turning point, experiencing the pediatric intensive care unit with anxiety and fear, and perception of support. When parents face their child having a congenital heart defect and plan heart surgery, the whole family is living through a stressful time and has to handle many difficult situations. Parents need support from the health care team.

Hypoplastic Left Heart Syndrome Sequencing Reveals a Novel NOTCH1 Mutation in a Family with Single Ventricle Defects

Hypoplastic left heart syndrome (HLHS) has been associated with germline mutations in 12 candidate genes and a recurrent somatic mutation in HAND1 gene. Using targeted and whole exome sequencing (WES) of heart tissue samples from HLHS patients, we sought to estimate the prevalence of somatic and germline mutations associated with HLHS. We performed Sanger sequencing of the HAND1 gene on 14 ventricular (9 LV and 5 RV) samples obtained from HLHS patients, and WES of 4 LV, 2 aortic, and 4 matched PBMC samples, analyzing for sequence discrepancy. We also screened for mutations in the 12 candidate genes implicated in HLHS. We found no somatic mutations in our HLHS cohort. However, we detected a novel germline frameshift/stop-gain mutation in NOTCH1 in a HLHS patient with a family history of both HLHS and hypoplastic right heart syndrome (HRHS). Our study, involving one of the first familial cases of single ventricle defects linked to a specific mutation, strengthens the association of NOTCH1 mutations with HLHS and suggests that the two morphologically distinct single ventricle conditions, HLHS and HRHS, may share a common molecular and cellular etiology. Finally, somatic mutations in the LV are an unlikely contributor to HLHS.

The Miracle Baby Grows Up: Hypoplastic Left Heart Syndrome in the Adult

PURPOSE OF REVIEW

Hypoplastic left heart syndrome (HLHS) is characterized by underdevelopment of the mitral valve, left ventricle, and aorta and is ultimately palliated with a single-ventricle repair. Universally fatal in infancy prior to the advent of modern surgical techniques, the majority of HLHS patients will now reach adulthood. However, despite improvements in early survival, the HLHS population continues to face significant morbidity and early mortality. This review delineates common sources of patient morbidity and highlights areas in need of additional research for this growing segment of the adult congenital heart disease population.

RECENT FINDINGS

It has become increasingly clear that palliated adult single ventricle patients, like those with HLHS, face significant life-long morbidity from elevated systemic venous pressures as a consequence of the Fontan procedure. Downstream organ dysfunction secondary to elevated Fontan pressures has the potential to significantly impact long-term management decisions, including strategies of organ allocation. Because of the presence of a morphologic systemic right ventricle, HLHS patients may be at even higher risk than other adult patients with a Fontan. Because the adult HLHS population continues to grow, recognition of common sources of patient morbidity and mortality is becoming increasingly important. A coordinated effort between patients and providers is necessary to address the many remaining areas of clinical uncertainty to help ensure continued improvement in patient prognosis and quality of life.

Cardiac Embryology and Molecular Mechanisms of Congenital Heart Disease: A Primer for Anesthesiologists

Congenital heart disease is diagnosed in 0.4% to 5% of live births and presents unique challenges to the pediatric anesthesiologist. Furthermore, advances in surgical management have led to improved survival of those patients, and many adult anesthesiologists now frequently take care of adolescents and adults who have previously undergone surgery to correct or palliate congenital heart lesions. Knowledge of abnormal heart development on the molecular and genetic level extends and improves the anesthesiologist's understanding of congenital heart disease. In this article, we aim to review current knowledge pertaining to genetic alterations and their cellular effects that are involved in the formation of congenital heart defects. Given that congenital heart disease can currently only occasionally be traced to a single genetic mutation, we highlight some of the difficulties that researchers face when trying to identify specific steps in the pathogenetic development of heart lesions.

Hospital costs and cost implications of co-morbid conditions for patients with single ventricle in the period through to Fontan completion

BACKGROUND

Patients undergoing palliative surgeries for single-ventricle conditions are affected by multiple comorbidities or non-cardiac conditions. The prevalence, costs and the cost implications of these conditions have not been assessed.

METHODS

Administrative costing records from four hospitals in Australia and New Zealand were linked with the Fontan registry database to analyze the inpatient resource use for co-morbid or non-cardiac conditions. Inpatient costing records from the birth year through to Fontan completion were available for 156 patients. The most frequent primary diagnoses were hypoplastic left heart syndrome (33%), double inlet left ventricle (13%), and tricuspid atresia (12%).

RESULTS

During the staged surgical treatment period, children had a mean of 10±6 inpatient admissions and spent 85±64days in hospital. Among these admissions, 3±5 were for non-cardiac conditions, totaling 21±41 inpatient days. Whilst cardiac surgeries were the major reason for resource use (77% of the total cost), other cardiac care that is not surgical contributed 5% and non-cardiac admissions 18% of the total cost. The three most prevalent non-cardiac diagnostic admission categories were 'Respiratory system', 'Digestive system', and 'Ear, nose, mouth and throat', affecting 28%, 21% and 34% of the patients respectively. Multivariate regression estimated that admissions for each of these categories resulted in an increased cost of $34,563 (P=0.08), $52,438 (P=0.05) and $10,525 (P=0.53) per patient respectively for the staged surgical treatment period.

CONCLUSIONS

Non-cardiac admissions for single-ventricle patients are common and have substantial resource implications. Further research assessing the causes of admission and extent to which admissions are preventable is warranted.

Cell Therapy Trials in Congenital Heart Disease

Dramatic evolution in medical and catheter interventions and complex surgeries to treat children with congenital heart disease (CHD) has led to a growing number of patients with a multitude of long-term complications associated with morbidity and mortality. Heart failure in patients with hypoplastic left heart syndrome predicated by functional single ventricle lesions is associated with an increase in CHD prevalence and remains a significant challenge. Pathophysiological mechanisms contributing to the progression of CHD, including single ventricle lesions and dilated cardiomyopathy, and adult heart disease may inevitably differ. Although therapeutic options for advanced cardiac failure are restricted to heart transplantation or mechanical circulatory support, there is a strong impetus to develop novel therapeutic strategies. As lower vertebrates, such as the newt and zebrafish, have a remarkable ability to replace lost cardiac tissue, this intrinsic self-repair machinery at the early postnatal stage in mice was confirmed by partial ventricular resection. Although the underlying mechanistic insights might differ among the species, mammalian heart regeneration occurs even in humans, with the highest degree occurring in early childhood and gradually declining with age in adulthood, suggesting the advantage of stem cell therapy to ameliorate ventricular dysfunction in patients with CHD. Although effective clinical translation by a variety of stem cells in adult heart disease remains inconclusive with respect to the improvement of cardiac function, case reports and clinical trials based on stem cell therapies in patients with CHD may be invaluable for the next stage of therapeutic development. Dissecting the differential mechanisms underlying progressive ventricular dysfunction in children and adults may lead us to identify a novel regenerative therapy. Future regenerative technologies to treat patients with CHD are exciting prospects for heart regeneration in general practice.

Interstage Weight Gain Is Associated With Survival After First-Stage Single-Ventricle Palliation

BACKGROUND

Low birth and operative weight have been identified as risk factors for death after first-stage single-ventricle palliation. We hypothesize that weight gain after the first-stage operation is associated with transplant-free interstage survival to admission for the second-stage operation.

METHODS

We used historical data from the National Pediatric Cardiology Quality Improvement Collaborative database to conduct a longitudinal study to assess the association between weight gain and transplant-free interstage survival. The primary predictor was weight gain. The primary outcome was transplant-free survival. We constructed a repeated-measures logistic regression model using the general estimating equation method to examine the association between weight gain and transplant-free interstage survival.

RESULTS

The study population included 1,501 infants who were discharged alive from the first-stage single-ventricle palliation between June 2008 and January 2015. Patients who underwent a hybrid operation (n = 132) or were lost to follow-up (n = 11) were excluded. Transplant-free interstage survival was 90% (1,228 of 1,358). The mean weight gain was 2.5 (SD, 1.0) kg. Adjusted for age at the time of each measurement, the number of measurements, age at discharge from the first-stage operation, sex, diagnosis, postoperative arrhythmia, postoperative complications, and discharge antibiotic therapy, each 100-g increase in weight was associated with an odds ratio of transplant-free interstage survival of 1.03 (95% confidence limit, 1.01, 1.05).

CONCLUSIONS

After first-stage single-ventricle palliation, interstage weight gain is significantly associated with transplant-free interstage survival.

MicroRNAs: pleiotropic players in congenital heart disease and regeneration

Congenital heart disease (CHD) is the leading cause of infant death, affecting approximately 4-14 live births per 1,000. Although surgical techniques and interventions have improved significantly, a large number of infants still face poor clinical outcomes. MicroRNAs (miRs) are known to coordinately regulate cardiac development and stimulate pathological processes in the heart, including fibrosis or hypertrophy and impair angiogenesis. Dysregulation of these regulators could therefore contribute (I) to the initial development of CHD and (II) at least partially to the observed clinical outcomes of many CHD patients by stimulating the aforementioned pathways. Thus, miRs may exhibit great potential as therapeutic targets in regenerative medicine. In this review we provide an overview of miR function and elucidate their role in selected CHDs, including hypoplastic left heart syndrome (HLHS), tetralogy of Fallot (TOF), ventricular septal defects (VSDs) and Holt-Oram syndrome (HOS). We then bridge this knowledge to the potential usefulness of miRs and/or their targets in therapeutic strategies for regenerative purposes in CHDs.

Psychosocial impact on families with an infant with a hypoplastic left heart syndrome during and after the interstage monitoring period - a prospective mixed-method study

AIMS AND OBJECTIVES

To investigate parents' experiences, coping ability and quality of life while monitoring their sick child with hypoplastic left heart syndrome at home.

BACKGROUND

Interstage home monitoring for children with hypoplastic left heart syndrome reduces interstage mortality between Norwood stages I and II. Little is known about the psychosocial impact of interstage home monitoring.

DESIGN

Prospective mixed-method study.

METHODS

This study assessed the psychosocial impact on parents during interstage home monitoring. This contains for quantitative assessment the Short Form Health Survey questionnaire and the Impact of Family Scale administered one and five weeks following discharge before and after stage II. For qualitative assessment, semi-structured interviews focussing on the postdischarge coping strategies were conducted twice, five weeks after hospital discharge before and after stage II.

RESULTS

Ten infants (eight males) with hypoplastic left heart syndrome (n = 7) or other types of univentricular heart malformations (n = 3), and their parents (nine mother/father two-parent households, one single mother) were included. There were no interstage deaths. Mental Health Composite Summary scores were low in both parents (mothers: 40·45 ± 9·07; fathers: 40·58 ± 9·69) and lowest for the item 'vitality' (mothers: 37·0 ± 19·46; fathers: 43·12 ± 25·9) before and after stage II. Impact of Family Scale values showed higher daily and social burdens for mothers. 'Becoming a family' was the most important task as coping strategy to equilibrate the fragile emotional balance. The parents judged interstage home monitoring as a protective intervention.

CONCLUSIONS

Although psychosocial burden before and after stage II remains high, becoming a family is an essential experience for parents and confirms their parenthood.

RELEVANCE TO CLINICAL PRACTICE

Healthcare professionals must be aware of parents' needs during this vulnerable interstage period and to provide psychosocial and nursing support.

Does superior caval vein pressure impact head growth in Fontan circulation?

BACKGROUND

Patients with bidirectional cavopulmonary anastomosis have unphysiologically high superior caval vein pressure as it equals pulmonary artery pressure. Elevated superior caval vein pressure may cause communicating hydrocephalus and macrocephaly. This study analysed whether there exists an association between head circumference and superior caval vein pressure in patients with single ventricle physiology.

METHODS

We carried out a retrospective analysis of infants undergoing Fontan completion at our institution from 2007 to 2013. Superior caval vein pressures were measured during routine catheterisation before bidirectional cavopulmonary anastomosis and Fontan completion as well as head circumference, adjusted to longitudinal age-dependent percentiles.

RESULTS

We included 74 infants in our study. Median ages at bidirectional cavopulmonary anastomosis and Fontan were 4.8 (1.6-12) and 27.9 (7-40.6) months, respectively. Head circumference showed significant growth from bidirectional cavopulmonary anastomosis until Fontan completion (7th (0-100th) versus 20th (0-100th) percentile). There was no correlation between superior caval vein pressure and head circumference before Fontan (R2=0.001). Children with lower differences in superior caval vein pressures between pre-bidirectional cavopulmonary anastomosis and pre-Fontan catheterisations showed increased growth of head circumference (R2=0.19).

CONCLUSIONS

Patients with moderately elevated superior caval vein pressure associated with single ventricle physiology did not have a tendency to develop macrocephaly. There is no correlation between superior caval vein pressure before Fontan and head circumference, but between bidirectional cavopulmonary anastomosis and Fontan head circumference increases significantly. This may be explained by catch-up growth of head circumference in patients with more favourable haemodynamics and concomitant venous pressures in the lower range. Further studies with focus on high superior caval vein pressures are needed to exclude or prove a correlation.

Parents' preparedness for their infants' discharge following first-stage cardiac surgery: development of a parental early warning tool

Aim The aim of this study was to explore parental preparedness for discharge and their experiences of going home with their infant after the first-stage surgery for a functionally univentricular heart.

BACKGROUND

Technological advances worldwide have improved outcomes for infants with a functionally univentricular heart over the last 3 decades; however, concern remains regarding mortality in the period between the first and second stages of surgery. The implementation of home monitoring programmes for this group of infants has improved this initial inter-stage survival; however, little is known about parents' experiences of going home, their preparedness for discharge, and parents' recognition of deterioration in their fragile infant.

METHOD

This study was conducted in 2011-2013; eight sets of parents were consulted in the research planning stage in September, 2011, and 22 parents with children aged 0-2 years responded to an online survey during November, 2012-March, 2013. Description of categorical data and deductive thematic analysis of the open-ended questions were undertaken.

RESULTS

Not all parents were taught signs of deterioration or given written information specific to their baby. The following three themes emerged from the qualitative data: mixed emotions about going home, knowledge and preparedness, and support systems.

CONCLUSIONS

Parents are not adequately prepared for discharge and are not well equipped to recognise deterioration in their child. There is a role for greater parental education through development of an early warning tool to address the gap in parents' understanding of signs of deterioration, enabling appropriate contact and earlier management by clinicians.

Secondary Combined Immunodeficiency in Pediatric Patients after the Fontan Operation: Three Case Reports

The Fontan operation or total cavopulmonal connection (TCPC) is a palliative surgical correction of rare and complex inborn cardiac malformations that are characterized by univentricular circulation. Protein-losing enteropathy (PLE) develops in 4-13% of patients after the Fontan procedure. Fontan-related PLE leads to secondary combined immunodeficiency marked by hypogammaglobulinemia and predominantly CD4+ lymphocytopenia. Here, we present 3 case reports of patients with secondary immunodeficiency after the Fontan operation. The severity of hypogammaglobulinemia correlated with the nature of the infectious complications; however, clinical manifestations of T cell deficiency such as severe viral or opportunistic infections were not observed. The clinical consequences of the secondary combined immunodeficiency were modified by immunoglobulin replacement treatment and antibiotic prophylaxis. Heart transplantation led to the resolution of PLE signs and the restitution of IgG levels in 1 transplanted patient. Our experience shows that the immunological follow-up was delayed in all 3 patients. We suggest that all patients should be followed regularly by a clinical immunologist after the Fontan surgery.

Translation and Testing of the Swedish Version of Iceland-Family Perceived Support Questionnaire With Parents of Children With Congenital Heart Defects

There is a need for a suitable instrument for the Swedish context that could measure family members' perceptions of cognitive and emotional support received from nurses. The purpose of this study was to translate and test the psychometric properties of the Swedish version of the Iceland-Family Perceived Support Questionnaire (ICE-FPSQ) and, further, to report perceptions of support from nurses by family members of children with congenital heart defects (CHDs). A sample of 97 parents of children with CHD, living in Sweden, completed the Swedish translation of ICE-FPSQ. The Swedish version of ICE-FPSQ was found to be reliable and valid in this context. Parents scored perceived family support provided by nurses working in pediatric outpatient clinics as low, which suggests that nurses in these outpatient contexts in Sweden offered family nursing only sparingly.

Hypoplastic left heart syndrome: a review

BACKGROUND

Hypoplastic left heart syndrome (HLHS) is an etiologically multifactorial congenital heart disease affecting one in 5,000 newborns. Thirty years ago there were no treatment options for this pathology and the natural course of the disease led to death, usually within the first weeks of life. Recently surgical palliative techniques have been developed allowing for a five-year survival in more than half the cases.

MATERIALS AND METHODS

We reviewed literature available on HLHS, specifically its anatomy, embryology and pathophysiology, and treatment. The Pubmed and ClinicalKey databases were searched using the key words hypoplastic left heart syndrome, foetal aortic valvuloplasty, foetal septoplasty, Norwood procedure, bidirectional Glenn procedure, Fontan procedure, hybrid procedure. The relevant literature was reviewed and included in the article. We reported a case from Children's Clinical University Hospital, Riga, to illustrate treatment tactics in Latvia.

RESULTS

There are three possible directions for therapy in newborns with HLHS: orthotopic heart transplantation, staged surgical palliation and palliative non-surgical treatment or comfort care. Another treatment mode - foetal therapy - has arisen. Staged palliation and full Fontan circulation is a temporary solution, however, the only means for survival until heart transplantation. Fifty to 70% of patients who have gone through all three stages of palliation live to the age of five years.

CONCLUSIONS

The superior mode of treatment is not yet clear and the management must be based on each individual case, the experience of each clinic, as well as the financial aspects and will of the patient's parents.

The design and fabrication of a three-dimensional bioengineered open ventricle

Current treatments in hypoplastic left heart syndrome (HLHS) include multiple surgeries to refunctionalize the right ventricle and/or transplant. The development of a tissue-engineered left ventricle (LV) would provide a therapeutic option to overcome the inefficiencies and limitations associated with current treatment options. This study provides a foundation for the development and fabrication of the bioengineered open ventricle (BEOV) model. BEOV molds were developed to emulate the human LV geometry; molds were used to produce chitosan scaffolds. BEOV were fabricated by culturing 30 million rat neonatal cardiac cells on the chitosan scaffold. The model demonstrated 57% cell retention following 4days culture. The average biopotential output for the model was 1615 µV. Histological assessment displayed the presence of localized cell clusters, with intercellular and cell-scaffold interactions. The BEOV provides a novel foundation for the development of a 3D bioengineered LV for application in HLHS. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2206-2217, 2017.

Prediction of imminent, severe deterioration of children with parallel circulations using real-time processing of physiologic data

OBJECTIVES

Sudden death is common in patients with hypoplastic left heart syndrome and comparable lesions with parallel systemic and pulmonary circulation from a common ventricular chamber. It is hypothesized that unforeseen acute deterioration is preceded by subtle changes in physiologic dynamics before overt clinical extremis. Our objective was to develop a computer algorithm to automatically recognize precursors to deterioration in real-time, providing an early warning to care staff.

METHODS

Continuous high-resolution physiologic recordings were obtained from 25 children with parallel systemic and pulmonary circulation who were admitted to the cardiovascular intensive care unit of Texas Children's Hospital between their early neonatal palliation and stage 2 surgical palliation. Instances of cardiorespiratory deterioration (defined as the need for cardiopulmonary resuscitation or endotracheal intubation) were found via a chart review. A classification algorithm was applied to both primary and derived parameters that were significantly associated with deterioration. The algorithm was optimized to discriminate predeterioration physiology from stable physiology.

RESULTS

Twenty cardiorespiratory deterioration events were identified in 13 of the 25 infants. The resulting algorithm was both sensitive and specific for detecting impending events, 1 to 2 hours in advance of overt extremis (receiver operating characteristic area = 0.91, 95% confidence interval = 0.88-0.94).

CONCLUSIONS

Automated, intelligent analysis of standard physiologic data in real-time can detect signs of clinical deterioration too subtle for the clinician to observe without the aid of a computer. This metric may serve as an early warning indicator of critical deterioration in patients with parallel systemic and pulmonary circulation.

The myocardial and coronary histopathology and pathogenesis of hypoplastic left heart syndrome

Hypoplastic left heart syndrome has the greatest mortality rate among all CHDs and without palliation is uniformly fatal. Despite noble efforts, the aetiology of this syndrome is unknown and a cure remains elusive. The genetic and anatomic heterogeneity of hypoplastic left heart syndrome supports a rethinking of old hypotheses and warrants further investigation into the histological and vascular variations recognised with this syndrome. In an effort to elucidate the pathogenesis of hypoplastic left heart syndrome, this review will focus on its unique myocardial and coronary pathology as well as evaluate the association of hypoplastic left heart syndrome with the endocardial fibroelastosis reaction.

Changes in Motor Development During a 4-Year Follow-up on Children With Univentricular Heart Defects

PURPOSE

To compare changes in motor development from 1 to 5 years of age among 18 children with hypoplastic left heart syndrome and 12 with univentricular heart to 42 children without heart defect.

METHODS

Motor development was assessed with the Alberta Infant Motor Scale and Movement Assessment Battery for Children (Movement ABC).

RESULTS

Children with hypoplastic left heart syndrome or univentricular heart had significantly lower scores on the Alberta Infant Motor Scale test at the age of 1 and on the Movement ABC test at the age of 5 years compared with controls. Children with clear abnormalities on brain magnetic resonance imaging had lower scores compared with those with normal images or mild changes, and their relative motor scores decreased during follow-up.

CONCLUSIONS

Some children with univentricular heart defects may benefit from physiotherapeutic interventions to support their motor development.

Long-Term Serial Follow-Up of Pulmonary Artery Size and Wall Shear Stress in Fontan Patients

Pulmonary arterial (PA) flow is abnormal after the Fontan operation and is marked by a lack of pulsatility. We assessed the effects of this abnormal flow on the size and function of the PA's in Fontan patients in long-term serial follow-up. Twenty-three Fontan patients with serial follow-up were included. Median age was 11.1 (9.5-16.0) years at baseline and 15.5 (12.5-22.7) years at follow-up. Median follow-up duration was 4.4 (4.0-5.8) years. Flow and size of the left pulmonary artery were determined using phase-contrast MRI. From this wall shear stress (WSS), distensibility and pulsatility were determined. A group of healthy peers was included for reference. Flow and pulsatility were significantly lower in patients than in controls (p < 0.001). Mean area was comparable in patients and controls, but distensibility was significantly higher in controls (p < 0.001). Mean and peak WSS were significantly lower in Fontan patients (p < 0.001). Between baseline and follow-up, there was a significant increase in normalized flow (15.1 (14.3-19.1) to 18.7 (14.0-22.6) ml/s/m(2), p = 0.023). Area, pulsatility, distensibility and WSS did not change, but there was a trend toward a lower mean WSS (p = 0.068). Multivariable regression analysis showed that flow, area and age were important predictors for WSS. WSS in Fontan patients is decreased compared to healthy controls and tends to decrease further with age. Pulsatility and distensibility are significantly lower compared to healthy controls. Pulmonary artery size, however, is not significantly different from healthy controls and long-term growth after Fontan operation is proportionate to body size.

Laparoscopic Nissen fundoplication in infants with hypoplastic left heart syndrome

BACKGROUND/PURPOSE

Patients with hypoplastic left heart syndrome (HLHS) experience a higher risk for complications from gastroesophageal reflux, prompting frequent need for fundoplication. Patients between stage I and II palliation ("interstage") are at particularly high operative risk because of the parallel nature of their pulmonary and systemic blood flow. Laparoscopic approach for fundoplication is common for pediatric patients. However, its safety in interstage HLHS is relatively unknown. We examined the perioperative physiologic burden of a laparoscopic fundoplication in HLHS patients.

METHODS

All patients who underwent open or laparoscopic fundoplication during the interstage period at our institution since 2006 were reviewed. Perioperative physiologic data, echocardiographic findings, survival, and complications were collected from the anesthetic record and patient chart.

RESULTS

Nineteen patients with HLHS had laparoscopic fundoplication, 13 (68%) during the interstage period, compared to 64 performed by the open approach. Ten (77%) of 13 interstage patients had perioperative hemodynamic instability. Incidence of instability between open and laparoscopic groups was not different. One laparoscopic patient required ECMO support for shunt thrombosis.

CONCLUSIONS

Despite a high incidence of hemodynamic instability, overall outcomes are consistent with those reported in the literature for this high-risk patient population. Laparoscopic approach for fundoplication during the interstage period appears to be a relatively safe option for these patients.

Hybrid Palliation in the Treatment of Hypoplastic Left Heart Syndrome

Purpose:To discuss hypoplastic left heart syndrome (HLHS) and inform nurse practitioners (NPs) working in primary care settings of this rare congenital heart deformity. This case study also examines the ethical issues advancements in medicine poses and illustrates issues NPs face when caring for a child with HLHS.Data Source:Large databases such as PubMed and CINAHL were accessed to obtain evidence-based articles for the specific heart condition and latest treatments. The data from the case was derived from an actual case, but the identity of the patient was changed to assure confidentiality.Conclusion:HLHS is a rare congenital heart deformity. Many treatment options are available, but a new treatment, the hybrid palliation, has offered new hope for many patients and their families.Implication for Practice:Patients with congenital heart conditions, including HLHS are living longer with new procedures being undertaken. The NP is likely to provide primary care to patients with congenital heart conditions, specifically HLHS. Patient care may be guided by awareness of this condition and the latest advancements in treatment.

Stem cell therapies in patients with single ventricle physiology

Single ventricle physiology, especially hypoplastic left heart syndrome, is one of the most high-risk lesions in children with congenital heart disease, and the ensuing heart failure remains as a major problem related to adverse outcomes in these patients. The field of stem cell therapy for heart failure has shown striking advances during the past 10 years, and many clinical trials using stem cell technologies have been conducted in adults, which suggest that stem cell therapy is associated with long-term improvement in cardiac function. Cardiac progenitor cells have recently been discovered, and their strong regenerative ability has been demonstrated in several studies. Although no large clinical trials have been performed in the field of congenital heart disease, recent investigations indicate that stem cell therapy may hold great potential to treat children with cardiac defects.

[Hypoplastic left heart syndrome: 10 year experience with staged surgical management]

Hypoplastic left heart syndrome (HLHS) is a lethal congenital heart disease in 95% of non-treated patients. Surgical staging is the main form of treatment, consisting of a 3-stage approach, beginning with the Norwood operation. Long term survival of treated patients is unknown in our country.

OBJECTIVES

1) To review our experience in the management of all patients seen with HLHS between January 2000 and June 2012. 2) Identify risk factors for mortality.

PATIENTS AND METHOD

Retrospective analysis of a single institution experience with a cohort of patients with HLHS. Clinical, surgical, and follow-up records were reviewed.

RESULTS

Of the 76 patients with HLHS, 9 had a restrictive atrial septal defect (ASD), and 8 had an ascending aorta ≤2mm. Of the 65 out of 76 patients that were treated, 77% had a Norwood operation with pulmonary blood flow supplied by a right ventricle to pulmonary artery conduit, 17% had a Norwood with a Blalock-Taussig shunt, and 6% other surgical procedure. Surgical mortality at the first stage was 23%, and for Norwood operation 21.3%. For the period between 2000-2005, surgical mortality at the first stage was 36%, and between 2005-2010, 15% (P=.05). Actuarial survival was 64% at one year, and 57% at 5years. Using a multivariate analysis, a restrictive ASD and a diminutive aorta were high risk factors for mortality.

CONCLUSIONS

Our immediate and long term outcome for staged surgical management of HLHS is similar to that reported by large centres. There is an improvement in surgical mortality in the second half of our experience. Risk factors for mortality are also identified.

Survival of Children With Hypoplastic Left Heart Syndrome

OBJECTIVE

To examine the survival of infants with hypoplastic left heart syndrome (HLHS) and potential influence of demographic and clinical characteristics on survival using population-based data.

METHODS

Infants with nonsyndromic HLHS (n = 212) born between 1979 and 2005 were identified through the Metropolitan Atlanta Congenital Defects Program. Vital status was ascertained through 2009 based on linkage with vital records. We estimated Kaplan-Meier survival probabilities stratified by select demographic and clinical characteristics.

RESULTS

The overall survival probability to 2009 was 24% and significantly improved over time: from 0% in 1979-1984 to 42% in 1999-2005. Survival probability was 66% during the first week, 27% during the first year of life, and 24% during the first 10 years. Survival of very low and low birth weight or preterm infants and those born in high-poverty neighborhoods was significantly poorer. For children with information on surgical intervention (n = 88), the overall survival was 52%, and preterm infants had significantly poorer survival (31%) compared with term infants (56%). For children who survived to 1 year of age, long-term survival was ∼90%.

CONCLUSIONS

Survival to adolescence of children with nonsyndromic HLHS born in metropolitan Atlanta has significantly improved in recent years, with those born full term, with normal birth weight, or in a low-poverty neighborhood having a higher survival probability. Survival beyond infancy to adolescence is high. A better understanding of the growing population of survivors with HLHS is needed to inform resource planning.

Recessive MYH6 Mutations in Hypoplastic Left Heart With Reduced Ejection Fraction

Background—

The molecular underpinnings of hypoplastic left heart are poorly understood. Staged surgical palliation has dramatically improved survival, yet eventual failure of the systemic right ventricle necessitates cardiac transplantation in a subset of patients. We sought to identify genetic determinants of hypoplastic left heart with latent right ventricular dysfunction in individuals with a Fontan circulation.

Methods and Results—

Evaluation of cardiac structure and function by echocardiography in patients with hypoplastic left heart and their first-degree relatives identified 5 individuals with right ventricular ejection fraction ≤40% after Fontan operation. Whole genome sequencing was performed on DNA from 21 family members, filtering for genetic variants with allele frequency <1% predicted to alter protein structure or expression. Secondary family-based filtering for de novo and recessive variants revealed rare inherited missense mutations on both paternal and maternal alleles of MYH6 , encoding myosin heavy chain 6, in 2 patients who developed right ventricular dysfunction 3 to 11 years postoperatively. Parents and siblings who were heterozygous carriers had normal echocardiograms. Protein modeling of the 4 highly conserved amino acid substitutions, residing in both head and tail domains, predicted perturbation of protein structure and function.

Conclusions—

In contrast to dominant MYH6 mutations with variable penetrance identified in other congenital heart defects and dilated cardiomyopathy, this study reveals compound heterozygosity for recessive MYH6 mutations in patients with hypoplastic left heart and reduced systemic right ventricular ejection fraction. These findings implicate a shared molecular basis for the developmental arrest and latent myopathy of left and right ventricles, respectively.

Magnetic resonance imaging catheter stress haemodynamics post-Fontan in hypoplastic left heart syndrome

AIMS

Exercise limitation is common post-Fontan. Hybrid X-ray and magnetic resonance imaging (XMR) catheterization allows haemodynamic assessment by means of measurement of ventricular volumes and flow in major vessels with simultaneous invasive pressures. We aim to assess haemodynamic response to stress in patients with hypoplastic left heart syndrome (HLHS) post-Fontan.

METHODS AND RESULTS

Prospective study of 13 symptomatic children (NHYA 2) with HLHS post-Fontan using XMR catheterization. Three conditions were applied: baseline (Stage 1), dobutamine at 10 µg/kg/min (Stage 2), and dobutamine at 20 µg/kg/min (Stage 3). Seven consecutive patients received inhaled nitric oxide (iNO) at peak stress. Control MRI data were from normal healthy adults. In the HLHS patients, baseline mean pulmonary vascular resistance (PVR) was 1.51 ± 0.59 WU m(2) and aortopulmonary collateral flow was 17.7 ± 13.6% of systemic cardiac output. Mean right ventricular end-diastolic pressure was 6.7 ± 2.5 mmHg which did not rise with stress. Cardiac index (CI) increased at Stage 2 in HLHS (40%) and controls (61%) but continued to increase at Stage 3 only in controls (19%) but not in HLHS. The blunted rise in CI in HLHS was due to a continuing fall in end-diastolic volume throughout stress, with no significant change in PVR or CI at peak stress in response to iNO.

CONCLUSION

Cardiac output post-Fontan in HLHS at peak stress is blunted due to a limitation in preload which is not responsive to inhaled pulmonary vasodilators in the setting of normal PVR.

Stem cell therapy and tissue engineering for correction of congenital heart disease

This review article reports on the new field of stem cell therapy and tissue engineering and its potential on the management of congenital heart disease. To date, stem cell therapy has mainly focused on treatment of ischemic heart disease and heart failure, with initial indication of safety and mild-to-moderate efficacy. Preclinical studies and initial clinical trials suggest that the approach could be uniquely suited for the correction of congenital defects of the heart. The basic concept is to create living material made by cellularized grafts that, once implanted into the heart, grows and remodels in parallel with the recipient organ. This would make a substantial improvement in current clinical management, which often requires repeated surgical corrections for failure of implanted grafts. Different types of stem cells have been considered and the identification of specific cardiac stem cells within the heterogeneous population of mesenchymal and stromal cells offers opportunities for de novo cardiomyogenesis. In addition, endothelial cells and vascular progenitors, including cells with pericyte characteristics, may be necessary to generate efficiently perfused grafts. The implementation of current surgical grafts by stem cell engineering could address the unmet clinical needs of patients with congenital heart defects.

Microarray analysis of 50 patients reveals the critical chromosomal regions responsible for 1p36 deletion syndrome-related complications

OBJECTIVE

Monosomy 1p36 syndrome is the most commonly observed subtelomeric deletion syndrome. Patients with this syndrome typically have common clinical features, such as intellectual disability, epilepsy, and characteristic craniofacial features.

METHOD

In cooperation with academic societies, we analyzed the genomic copy number aberrations using chromosomal microarray testing. Finally, the genotype-phenotype correlation among them was examined.

RESULTS

We obtained clinical information of 86 patients who had been diagnosed with chromosomal deletions in the 1p36 region. Among them, blood samples were obtained from 50 patients (15 males and 35 females). The precise deletion regions were successfully genotyped. There were variable deletion patterns: pure terminal deletions in 38 patients (76%), including three cases of mosaicism; unbalanced translocations in seven (14%); and interstitial deletions in five (10%). Craniofacial/skeletal features, neurodevelopmental impairments, and cardiac anomalies were commonly observed in patients, with correlation to deletion sizes.

CONCLUSION

The genotype-phenotype correlation analysis narrowed the region responsible for distinctive craniofacial features and intellectual disability into 1.8-2.1 and 1.8-2.2 Mb region, respectively. Patients with deletions larger than 6.2 Mb showed no ambulation, indicating that severe neurodevelopmental prognosis may be modified by haploinsufficiencies of KCNAB2 and CHD5, located at 6.2 Mb away from the telomere. Although the genotype-phenotype correlation for the cardiac abnormalities is unclear, PRDM16, PRKCZ, and RERE may be related to this complication. Our study also revealed that female patients who acquired ambulatory ability were likely to be at risk for obesity.

Physical and neurodevelopmental outcomes in children with single-ventricle circulation

OBJECTIVE

To investigate longer-term physical and neurodevelopmental outcomes of patients with hypoplastic left heart syndrome (HLHS) compared with other patients with functionally single-ventricle circulation surviving beyond the age of 10 years.

DESIGN

A retrospective, observational study from a UK tertiary centre for paediatric cardiology.

RESULTS

58 patients with HLHS and 44 non-HLHS patients with single-ventricle physiology were included. Subjective reduction in exercise tolerance was reported in 72% (95% CI 61% to 84%) of patients with HLHS and 45% (31% to 60%) non-HLHS patients. Compared with non-HLHS patients, educational concerns were reported more frequently in patients with HLHS, 41% (29% to 54%) vs 23% (10% to 35%), as was a diagnosis of a behaviour disorder (autism or attention deficit hyperactivity disorder) 12% (4% to 21%) vs 0%, and referral to other specialist services 67% (55% to 79%) vs 48% (33% to 63%).

CONCLUSIONS

Within a group of young people with complex congenital heart disease, those with HLHS are likely to have worse physical, psychological and educational outcomes.