Congenital Heart Surgery Nomenclature and Database Project: hypoplastic left heart syndrome

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.

Fetal Echocardiography in Predicting Postnatal Outcome in Borderline Left Ventricle

OBJECTIVES

 Prenatal prediction of postnatal univentricular versus biventricular circulation in patients with borderline left ventricle (bLV) remains challenging. This study investigated prenatal fetal echocardiographic parameters and postnatal outcome of patients with a prenatally diagnosed bLV.

METHODS

 We report a retrospective study of bLV patients at four prenatal centers with a follow-up of one year. BLV was defined as z-scores of the left ventricle (LV) between -2 and -4. Single-ventricle palliation (SVP), biventricular repair (BVR), and no surgical or catheter-based intervention served as the dependent outcome. Prenatal ultrasound parameters were used as independent variables. Cut-off values from receiver operating characteristic curves (ROC) were determined for significant discrimination between outcomes.

RESULTS

 A total of 54 patients were diagnosed with bLV from 2010 to 2018. All were live births. Out of the entire cohort, 8 (15 %) received SVP, 34 (63 %) BVR, and 12 (22 %) no intervention. There was no significant difference with regard to genetic or extracardiac anomalies. There were significantly more patients with endocardial fibroelastosis (EFE) in the SVP group compared to the BVR group (80 % vs. 10 %), (p < 0.001). Apex-forming LV (100 % vs. 70 %) and lack of retrograde arch flow (20 % vs. 80 %) were associated with no intervention (p < 0.001). With respect to BVR vs. SVP, the LV sphericity index provided the highest specificity (91.7 %) using a cutoff value of ≤ 0.5.

CONCLUSION

 The majority of bLV patients maintained biventricular circulation. EFE, retrograde arch flow, and LV sphericity can be helpful parameters for counseling parents and further prospective studies can be developed.

Hypoplastic Left Ventricle: Hypoplastic Left Heart Complex

Hypoplastic left heart syndrome (HLHS) without intrinsic valvar stenosis or atresia is synonymous with the term hypoplastic left heart complex (HLHC) and is defined as a cardiac malformation at the milder end of the spectrum of HLHS with normally aligned great arteries without a common atrioventricular junction, characterized by underdevelopment of the left heart with significant hypoplasia of the left ventricle and hypoplasia of the aortic or mitral valve, or both valves, in the absence of intrinsic valvar stenosis or atresia, and with hypoplasia of the ascending aorta and aortic arch. This article describes the definitions, nomenclature, and classification of HLHC; the indications and contraindications for biventricular repair of HLHC; the surgical treatment of HLHC; and the associated outcomes.

The Left Ventricular Myocardium in Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a collective term applied to severe congenital cardiac malformations, characterised by a combination of abnormalities mainly affecting the left ventricle, associated valves, and ascending aorta. Although in clinical practice HLHS is usually sub-categorised based on the patency of the mitral and aortic (left-sided) valves, it is also possible to comprehensively categorise HLHS into defined sub-groups based on the left ventricular morphology. Here, we discuss the published human-based studies of the ventricular myocardium in HLHS, evaluating whether the available evidence is in keeping with this ventricular morphology concept. Specifically, we highlight results from histological studies, indicating that the appearance of cardiomyocytes can be different based on the sub-group of HLHS. In addition, we discuss the histological appearances of endocardial fibroelastosis (EFE), which is a common feature of one specific sub-group of HLHS. Lastly, we suggest investigations that should ideally be undertaken using HLHS myocardial tissues at early stages of HLHS development to identify biological pathways and aid the understanding of HLHS aetiology.

The Effects of Exercise Training on Cardiopulmonary Exercise Testing and Cardiac Biomarkers in Adult Patients with Hypoplastic Left Heart Syndrome and Fontan Circulation

Background: Several studies have shown that adult patients with Hypoplastic Left Heart Syndrome (HLHS) and Fontan circulation have a reduced exercise tolerance that affects daily life. Recent studies have investigated the effects of aerobic exercise training in patients with univentricular heart; however, this research topic is still poorly studied. The aim of this study was to evaluate the effects of an aerobic exercise training program on cardiopulmonary exercise testing parameters and cardiac biomarkers in patients with HLHS. Methods: We enrolled 12 patients with a mean age of 24 ± 2.5 years (range 22−27 years), 50% male, with HLHS at Bambino Gesù Children’s Hospital IRCCS. All patients underwent a cardiopulmonary test and blood sampling before (T0) and after (T1) a 4-week aerobic exercise program. Cardiac biomarkers hs-cTnT, NT-proBNP, ST2, GDF-15 were studied. Results: Data analysis demonstrated an increase in cardiorespiratory performance after 4 weeks of aerobic exercise training activity. In particular, the data showed a significant improvement in test duration (p < 0.05), heart rate at rest (p < 0.05), heart rate recovery 1 min (p < 0.05), VO2 max (p < 0.01) and oxygen uptake efficiency slope (p < 0.05). At the same time, the data showed a significant reduction in NT-proBNP and ST2 values (p < 0.01 and p < 0.05, respectively) and a significant increase in GDF-15 (p < 0.01). No significant changes were found between the hs-cTnT values. Conclusions: Our study demonstrated the 4-week efficacy of an aerobic training program in improving cardiorespiratory performance and cardiac biomarker values in adult patients with HLHS and Fontan circulation. More studies with larger numbers of patients will be needed to confirm these data.

Significance of α-Myosin Heavy Chain (MYH6) Variants in Hypoplastic Left Heart Syndrome and Related Cardiovascular Diseases

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) with complex genetic inheritance. HLHS segregates with other left ventricular outflow tract (LVOT) malformations in families, and can present as either an isolated phenotype or as a feature of a larger genetic disorder. The multifactorial etiology of HLHS makes it difficult to interpret the clinical significance of genetic variants. Specific genes have been implicated in HLHS, including rare, predicted damaging MYH6 variants that are present in >10% of HLHS patients, and which have been shown to be associated with decreased transplant-free survival in our previous studies. MYH6 (α-myosin heavy chain, α-MHC) variants have been reported in HLHS and numerous other CHDs, including LVOT malformations, and may provide a genetic link to these disorders. In this paper, we outline the MYH6 variants that have been identified, discuss how bioinformatic and functional studies can inform clinical decision making, and highlight the importance of genetic testing in HLHS.

Left heart hypoplasia in the fetus: echocardiographic predictors of outcome

INTRODUCTION

Fetal left heart hypoplasia (LHH) with an apex-forming left ventricle may require neonatal intervention but it is difficult to predict.

METHODS

We performed a retrospective study of fetuses with LHH defined as normal segmental anatomy, apex-/near-apex forming left ventricle, and ≥1 left-sided Z-score <-2 between 1997-2014. Fetuses with mitral or aortic atresia, critical aortic stenosis, extracardiac anomalies, or fetal intervention were excluded. Classification and regression tree analyses (CART) were performed to construct algorithms to predict postnatal circulation: no surgery versus biventricular surgery versus single ventricle (SV) palliation.

RESULTS

Among 138 included fetuses, 52 (37%) underwent neonatal surgery, with 10 (7%) undergoing SV palliation. The strongest single outcome discriminator was exclusively left-to-right flow foramen ovale (FO) flow >32 weeks gestational age (seen in 0% with no surgery, 22% with biventricular surgery, 88% with SV palliation). On CART analysis >32 weeks GA, fetuses with right-to-left FO flow and aortopulmonary ratio >0.76 had 0% probability of neonatal surgery, while those with left-to-right FO flow and mitral valve Z-score <-3.6 had a 70% probability of SV palliation.

CONCLUSION

SV palliation is an uncommon outcome of fetal LHH. Fetal FO flow and other echocardiographic measures can help determine risk and type of postnatal intervention. This article is protected by copyright. All rights reserved.

Postmortem Assessment of Isolated Congenital Heart Defects Remains Essential Following Termination of Pregnancy

OBJECTIVES

To investigate the correlation between prenatal ultrasound (US) and autopsy findings in pregnancies terminated due to isolated congenital heart defects (CHDs), including CHDs associated with heterotaxy syndrome.

MATERIALS AND METHODS

The material consists of 67 fetuses with prenatally detected isolated CHDs or CHDs associated with heterotaxy syndrome at a tertiary center in Norway between 1985 and 2014. The main CHDs were categorized into subdiagnoses of CHDs in accordance with ICD-10. The US and autopsy findings were categorized according to degree of concordance.

RESULTS

Gestational age at termination was 12 + 0-22 + 6 weeks. Hypoplastic left heart syndrome was the most common main diagnosis among the 67 fetuses (32.8%). There was full agreement between US and autopsy findings in 97.4% (222/228) of all subdiagnoses. The discrepant findings in three fetuses had no influence on the decision to terminate the pregnancy.

CONCLUSIONS

The correlation was high between prenatal US and postmortem findings in fetuses with isolated CHDs. Meticulous assessment of cardiac anatomy is particularly necessary when the decision to terminate relies on isolated CHDs. The trend of earlier termination challenges verification of diagnoses at autopsy. Consequently, the fetus should be examined at a tertiary center with fetal medicine specialists, pediatric cardiologists and perinatal pathologists.

Nomenclature for Pediatric and Congenital Cardiac Care: Unification of Clinical and Administrative Nomenclature - The 2021 International Paediatric and Congenital Cardiac Code (IPCCC) and the Eleventh Revision of the International Classification of Diseases (ICD-11)

Substantial progress has been made in the standardization of nomenclature for paediatric and congenital cardiac care. In 1936, Maude Abbott published her Atlas of Congenital Cardiac Disease, which was the first formal attempt to classify congenital heart disease. The International Paediatric and Congenital Cardiac Code (IPCCC) is now utilized worldwide and has most recently become the paediatric and congenital cardiac component of the Eleventh Revision of the International Classification of Diseases (ICD-11). The most recent publication of the IPCCC was in 2017. This manuscript provides an updated 2021 version of the IPCCC. The International Society for Nomenclature of Paediatric and Congenital Heart Disease (ISNPCHD), in collaboration with the World Health Organization (WHO), developed the paediatric and congenital cardiac nomenclature that is now within the eleventh version of the International Classification of Diseases (ICD-11). This unification of IPCCC and ICD-11 is the IPCCC ICD-11 Nomenclature and is the first time that the clinical nomenclature for paediatric and congenital cardiac care and the administrative nomenclature for paediatric and congenital cardiac care are harmonized. The resultant congenital cardiac component of ICD-11 was increased from 29 congenital cardiac codes in ICD-9 and 73 congenital cardiac codes in ICD-10 to 318 codes submitted by ISNPCHD through 2018 for incorporation into ICD-11. After these 318 terms were incorporated into ICD-11 in 2018, the WHO ICD-11 team added an additional 49 terms, some of which are acceptable legacy terms from ICD-10, while others provide greater granularity than the ISNPCHD thought was originally acceptable. Thus, the total number of paediatric and congenital cardiac terms in ICD-11 is 367. In this manuscript, we describe and review the terminology, hierarchy, and definitions of the IPCCC ICD-11 Nomenclature. This article, therefore, presents a global system of nomenclature for paediatric and congenital cardiac care that unifies clinical and administrative nomenclature.The members of ISNPCHD realize that the nomenclature published in this manuscript will continue to evolve. The version of the IPCCC that was published in 2017 has evolved and changed, and it is now replaced by this 2021 version. In the future, ISNPCHD will again publish updated versions of IPCCC, as IPCCC continues to evolve.

Role of gated cardiac computed tomographic angiography in the evaluation of postsurgical complications after stage I Norwood procedure and its implications on management: a comparative study with two-dimensional echocardiography

BACKGROUND

The Norwood procedure is the first part of a three-stage surgical palliation for patients with functionally single ventricle anatomy. Complications after the stage I operation are not uncommon. Transthoracic echocardiography (TTE) is traditionally the mainstay for evaluation.

OBJECTIVE

The purpose of our study is to compare gated cardiac computed tomographic angiography (CCTA) with TTE when evaluating for postoperative complications after stage I Norwood procedure and to describe management implications.

MATERIALS AND METHODS

A retrospective chart review of all patients over a 4-year period who underwent nonelective urgent CCTA for suspected complications related to stage I Norwood procedure was performed. Elective CCTA studies before stage II palliation were excluded. Patient demographics, CCTA and TTE findings, as well as interventions performed, were recorded.

RESULTS

Thirty-four patients were included. The mean age at CCTA was 63 days (range: 4-210 days). All patients had a recent TTE with a mean time interval between TTE and CCTA of 2 days. CCTA detected 56 abnormalities in 30 patients, with 23 directly related to postsurgical complications, including shunt-related complications (10/23, 43%), Damus-Kaye-Stansel anastomotic narrowing (2/23, 9%) and neo-aortic arch/branch vessel abnormalities (11/23, 48%). These complications were managed as follows: surgery (9, 39%), catheter-based intervention (7, 30%), medical (4, 17%) and no change in management (3, 13%). TTE did not detect 8/23 (35%) findings found on CCTA, of which 75% were either managed with surgery (4/8, 50%) or catheter-based intervention (2/8, 25%).

CONCLUSION

CCTA plays an important role in detecting surgical complications after stage I Norwood procedure and demonstrates additional findings that have direct management implications.

Functional and molecular effects of TNF-α on human iPSC-derived cardiomyocytes

Proinflammatory molecule tumor necrosis factor alpha (TNF-α) is predominantly elevated in cytokine storm as well as worsening cardiac function. Here we model the molecular and functional effects of TNF-α in cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSC). We found that treatment of hiPSC-CMs with TNF-α increased reactive oxygen species (ROS) and caspase 3/7 activity and caused cell death and apoptosis. TNF-α treatment also resulted in dysregulation of cardiomyocyte function with respect to the increased abnormal calcium handling, calcium wave propagation between cells and excitation–contraction coupling. We also uncovered significant changes in gene expression and protein localization caused by TNF-α treatment. Notably, TNF-α treatment altered the expression of ion channels, dysregulated cadherins, and affected the localization of gap-junction protein connexin-43. In addition, TNF-α treatment up-regulated IL-32 (a human specific cytokine, not present in rodents and an inducer of TNF-α) and IL-34 and down-regulated glutamate receptors and cardiomyocyte contractile proteins. These findings provide insights into the molecular and functional consequences from the exposure of human cardiomyocytes to TNF-α. Our study provides a model to incorporate inflammatory factors into hiPSC-CM-based studies to evaluate mechanistic aspects of heart disease.

Effect of left atrial ligation-driven altered inflow hemodynamics on embryonic heart development: clues for prenatal progression of hypoplastic left heart syndrome

Congenital heart defects (CHDs) are abnormalities in the heart structure present at birth. One important condition is hypoplastic left heart syndrome (HLHS) where severely underdeveloped left ventricle (LV) cannot support systemic circulation. HLHS usually initiates as localized tissue malformations with no underlying genetic cause, suggesting that disturbed hemodynamics contribute to the embryonic development of these defects. Left atrial ligation (LAL) is a surgical procedure on embryonic chick resulting in a phenotype resembling clinical HLHS. In this study, we investigated disturbed hemodynamics and deteriorated cardiac growth following LAL to investigate possible mechanobiological mechanisms for the embryonic development of HLHS. We integrated techniques such as echocardiography, micro-CT and computational fluid dynamics (CFD) for these analyses. Specifically, LAL procedure causes an immediate flow disturbance over atrioventricular (AV) cushions. At later stages after the heart septation, it causes hemodynamic disturbances in LV. As a consequence of the LAL procedure, the left-AV canal and LV volume decrease in size, and in the opposite way, the right-AV canal and right ventricle volume increase. According to our CFD analysis, LAL results in an immediate decrease in the left AV canal WSS levels for 3.5-day (HH21) pre-septated hearts. For 7-day post-septated hearts (HH30), LAL leads to further reduction in WSS levels in the left AV canal, and relatively increased WSS levels in the right AV canal. This study demonstrates the critical importance of the disturbed hemodynamics during the heart valve and ventricle development.

Follow-up after biventricular repair of the hypoplastic left heart complex

OBJECTIVES

In hypoplastic left heart complex patients, biventricular repair is preferred over staged-single ventricle palliation; however, there are too few studies to support either strategy. Therefore, we retrospectively characterized our patient cohort with hypoplastic left heart complex after biventricular repair to measure left-sided heart structures and assess our treatment strategy.

METHODS

Patients with hypoplastic left heart complex who had biventricular repair between 2004 and 2018 were retrospectively reviewed. Operative results were evaluated and echocardiographic mitral valve (MV) and aortic valve (AoV) dimensions, left ventricular length and left ventricular internal diastolic diameter (LVIDd) were measured preoperatively and during follow-up after 0.5, 1, 3, 5 and 10 years.

RESULTS

In 32 patients, the median age at surgery was 10 (interquartile range 5.0) days. The median follow-up was 6.19 (interquartile range 6.04) years. During the 10-year follow-up, the mean Z-scores increased from -2.82 to -1.49 and from -2.29 to 0.62 for MV and AoV, respectively. Analysis of variance results with post hoc paired t-tests showed that growth of left-sided heart structures was accelerated in the first year after repair, but was not equal, with the MV lagging behind the AoV (P = 0.033), resulting in significantly smaller MV Z-scores compared with AoV Z-scores at 10-year follow-up (P < 0.001). There were 2 (6%) early deaths. The major adverse events occurred in 4 (13%) patients. The surgical or catheter-based reintervention was required in 14 (44%) patients.

CONCLUSIONS

The growth rate of heart structures was most prominent during the first year after biventricular repair with lower growth rate of the MV compared with the AoV.

Detailed Echocardiographic Measurements of Individual Chamber in a Chinese Cohort of Hypoplastic Left Heart Syndrome and Comparison with Normal Fetuses via Z-score Modeling

Hypoplastic left heart syndrome (HLHS) is a rare, but exceptionally serious, congenital heart defect. We aimed to explore the best-fitted Z-score models for individual chamber dimension and to draw a comparison between fetuses with HLHS and the normal Chinese cohort. We made measurements of 1674 healthy fetuses and 79 fetuses with HLHS, undertaking echocardiography. Normal fetal cardiovascular Z-score formulae were established by curve-fitting with 5 algorithmic functions and weighted regression of absolute residuals. Classic linear models were fitted for left ventricular diameter against gestational age, and log-transformed linear-power models-were statistically better for left ventricular length, diameter of left atrium and ascending aorta. Fetuses with HLHS manifested significantly lower Z-score means (≤3.5) for these 4 parameters and the vast majority (∼90%) lay beyond -2. Overall, cardiovascular Z-score equations were reliably constructed in a larger Chinese cohort, and their application should benefit evaluation and diagnosis of HLHS.

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.

Pre-intervention morphologic and functional echocardiographic characteristics of neonates with critical left heart obstruction: a Congenital Heart Surgeons Society (CHSS) inception cohort study

AIMS

The aims of this study were to provide a detailed descriptive analysis of pre-intervention morphologic and functional echocardiographic parameters in a large, unselected, multicentre cohort of neonates diagnosed with critical left heart obstruction and to compare echocardiographic features between the different subtypes of left-sided lesions.

METHODS AND RESULTS

Pre-intervention echocardiograms for 651 patients from 19 Congenital Heart Surgeons' Society (CHSS) institutions were reviewed in a core lab according to a standardized protocol including >150 morphologic and functional variables. The four most common subtypes of lesions were: aortic atresia (AA)/mitral atresia (MA) (29% of patients), AA/mitral stenosis (MS) (20%), aortic stenosis (AS)/MS (26%), and isolated AS (iAS) (18%). Only 17% of patients with AS/MS had an apex-forming left ventricle, compared with 0% of those with AA/MA and AA/MS (P < 0.0001). Aortic arch hypoplasia and coarctation were common across all four groups, while those with AA/MA and AA/MS had the smallest ascending aorta diameters. Flow in the ascending aorta was retrograde in 43% and 10% of the patients with AS/MS and iAS, respectively. The right ventricle was apex forming in 100% of patients with AA/MA and AA/MS, 96% with AS/MS and 70% with iAS (P < 0.0001). Moderate to severe tricuspid regurgitation was present in 13% of all patients.

CONCLUSION

This large multi-institutional study generates insight into the distribution of the functional and morphologic spectrum in patients with critical left-sided heart disease and identifies differences in these functional and morphologic characteristics between the main anatomic subtypes of critical left heart obstruction.

A novel, data-driven conceptualization for critical left heart obstruction

BACKGROUND

Qualitative features of aortic and mitral valvar pathology have traditionally been used to classify congenital cardiac anomalies for which the left heart structures are unable to sustain adequate systemic cardiac output. We aimed to determine if novel groups of patients with greater clinical relevance could be defined within this population of patients with critical left heart obstruction (CLHO) using a data-driven approach based on both qualitative and quantitative echocardiographic measures.

METHODS

An independent standardized review of recordings from pre-intervention transthoracic echocardiograms for 651 neonates with CLHO was performed. An unsupervised cluster analysis, incorporating 136 echocardiographic measures, was used to group patients with similar characteristics. Key measures differentiating the groups were then identified.

RESULTS

Based on all measures, cluster analysis linked the 651 neonates into groups of 215 (Group 1), 338 (Group 2), and 98 (Group 3) patients. Aortic valve atresia and left ventricular (LV) end diastolic volume were identified as significant variables differentiating the groups. The median LV end diastolic area was 1.35, 0.69, and 2.47 cm² in Groups 1, 2, and 3, respectively (p < 0.0001). Aortic atresia was present in 11% (24/215), 87% (294/338), and 8% (8/98), in Groups 1, 2, and 3, respectively (p < 0.0001). Balloon aortic valvotomy was the first intervention for 9% (19/215), 2% (6/338), and 61% (60/98), respectively (p < 0.0001). For those with an initial operation, single ventricle palliation was performed in 90% (176/215), 98% (326/338), and 58% (22/38) (p < 0.0001). Overall mortality in each group was 27% (59/215), 41% (138/338), and 12% (12/98) (p < 0.0001).

CONCLUSIONS

Using a data-driven approach, we conceptualized three distinct patient groups, primarily based quantitatively on baseline LV size and qualitatively by the presence of aortic valve atresia. Management strategy and overall mortality differed significantly by group. These groups roughly correspond anatomically and are analogous to multi-level LV hypoplasia, hypoplastic left heart syndrome, and critical aortic stenosis, respectively. Our analysis suggests that quantitative and qualitative assessment of left heart structures, particularly LV size and type of aortic valve pathology, may yield conceptually more internally consistent groups than a simplistic scheme limited to valvar pathology alone.

The HAND1 frameshift A126FS mutation does not cause hypoplastic left heart syndrome in mice

Aims

To test if a human Hand1 frame shift mutation identified in human samples is causative of hypoplastic left heart syndrome (HLHS).

Methods and results

HLHS is a poorly understood single ventricle congenital heart defect that affects two to three infants in every 10 000 live births. The aetiologies of HLHS are largely unknown. The basic helix-loop-helix transcription factor HAND1 is required for normal heart development. Interrogation of HAND1 sequence from fixed HLHS tissues identified a somatic frame-shift mutation at Alanine 126 (NP_004812.1 p.Ala126Profs13X defined as Hand1A126fs). Hand1A126fs creates a truncated HAND1 protein that predictively functions as dominant negative. To determine if this mutation is causative of HLHS, we engineered a conditional Hand1A126fs mouse allele. Activation of this allele with Nkx2.5Cre results in E14.5 lethality accompanied by cardiac outflow tract and intraventricular septum abnormalities. Using αMHC-Cre or Mef2CAHF-Cre to activate Hand1A126fs results in reduced phenotype and limited viability. Left ventricles of Hand1A126FS mutant mice are not hypoplastic.

Conclusions

Somatically acquired Hand1A126FS mutation is not causative of HLHS. Hand1A126FS mutation does exhibit embryonic lethal cardiac defects that reflect a dominant negative function supporting the critical role of Hand1 in cardiogenesis.

Cerebral Abscess in Young Adult with Hypoplastic Left Heart Syndrome

BACKGROUND

Cerebral abscesses are rare, potentially life-threatening entities that result from local spread or hematogenous dissemination to the brain. Prompt diagnosis and initiation of treatment is key in lowering morbidity and preventing mortality associated with cerebral abscesses. Congenital heart diseases with right-to-left intracardiac shunts can be complicated by brain abscesses via paradoxical embolism of infected microthrombi. Hypoplastic left heart syndrome (HLHS) is a rare congenital heart disease characterized by an underdeveloped left heart that uses intracardiac shunting to achieve adequate systemic circulation. We present the first reported case of a cerebral abscess in a patient with HLHS. The pathophysiology of HLHS and how it predisposes patients to development of cerebral abscesses is discussed.

CASE DESCRIPTION

A 25-year-old male was transferred to our institution complaining of headache, nausea, and vomiting. The patient was not an intravenous (IV) drug user, and serologic testing was negative for human immunodeficiency virus. Magnetic resonance imaging revealed a 2.6-cm left occipital abscess, which was surgically resected without complication, and the patient was treated with IV antibiotics.

CONCLUSION

HLHS is a rare congenital cardiac malformation. The long-term outcome of patients with this condition continues to improve as treatment paradigms evolve. As such, patients with HLHS are living longer, and their potential to develop cerebral abscesses secondary to their unique systemic circulation is increasing with improved life expectancy. Surgeons and physicians should maintain a high index of suspicion for cerebral abscess in the setting of HLHS.

Lessons from the Barn to the Operating Suite: A Comprehensive Review of Animal Models for Fetal Surgery

The International Fetal Medicine and Surgery Society was created in 1982 and proposed guidelines for fetal interventions that required demonstrations of the safety and feasibility of intended interventions in animal models prior to application in humans. Because of their short gestation and low cost, small animal models are useful in early investigation of fetal strategies. However, owing to the anatomic and physiologic differences between small animals and humans, repeated studies in large animal models are usually needed to facilitate translation to humans. Ovine (sheep) models have been used the most extensively to study the pathophysiology of congenital abnormalities and to develop techniques for fetal interventions. However, nonhuman primates have uterine and placental structures that most closely resemble those of humans. Thus, the nonhuman primate is the ideal model to develop surgical and anesthetic techniques that minimize obstetrical complications.

Evaluation of Residual Coarctation in Infants with a Single Right Ventricle after Stage I Palliation

In infants with a single right ventricle (RV), stage I palliation involves aortic reconstruction, systemic-to-pulmonary shunt placement, and atrial septectomy. Many require re-intervention for residual coarctation of the aorta (CoA). Doppler echocardiography can detect residual CoA in most infants, but its ability to predict severity has not been studied. This study compares gradients from Doppler interrogation to those from cardiac catheterization in infants with residual CoA. We performed a retrospective study of infants after stage I palliation from 2000 to 2014. Infants with an echocardiogram and catheterization before the second-stage palliative surgery were included. Infants with an echocardiogram >30 days before catheterization were excluded. Doppler-derived gradients were compared to catheterization-derived gradients. Echocardiographic assessment of tricuspid valve (TV) and RV function were recorded. The cohort included 95 infants, and thirty-three (35%) had CoA. Doppler-derived and catheterization-derived gradients correlated weakly in infants with CoA (r = 0.37, p = 0.036) and without CoA (r = 0.35, p = 0.005). Among infants with CoA, 17/33 had none or trivial tricuspid regurgitation (TR) and normal RV function, and Doppler-derived gradients correlated with catheterization gradients in this group (r = 0.71, p = 0.001). In 16/33 infants with ≥moderate TR or RV dysfunction, gradients did not correlate (r = -0.003, p = 0.992). After a stage I palliation in infants with single RV and CoA, Doppler-derived gradients poorly predicted the severity of CoA. Infants with normal TV or RV function had Doppler-derived gradients more predictive of catheterization-derived gradients. Doppler-derived gradients have limited utility in determining the severity of CoA after a stage I palliation.

Hypoplastic left heart syndrome: current perspectives

Since the first successful intervention for hypoplastic left heart syndrome (HLHS) was undertaken by Norwood in 1983, there have been many advancements in the pre-, intra-, and postoperative care of these children for a diagnosis that just 25 years ago was almost certainly a fatal one. This paper aims to describe the most recent trends and perspectives on the treatment of HLHS. In particular, we will discuss the five current options for HLHS, including Norwood stage I as the beginning to 3-stage palliation, transplant, true hybrid, hybrid-bridge-to-Norwood, and compassionate care.

Aortic arch obstruction neonates with biventricular physiology: left-open compared to closed inter-atrial communication during primary repair--a retrospective study

Background

Leaving an inter-atrial communication (IAC) open for left atrial decompression is often recommended in neonates with aortic arch obstruction undergoing primary repair. In this study, outcomes in these patients were compared to those with intact atrial septum after repair.

Methods

Between 2000 and 2013, 53 consecutive neonates with severe aortic arch obstruction (hypoplasia: n = 45, interruption: n = 8) underwent primary repair from an anterior approach. Median age and weight were 8 days (range: 2–30) and 3.2 kg (range: 2.4-4.4), respectively. Cardiac morphology included a ventricular septal defect (VSD, large: n = 28, small: n = 7), malposition of great arteries (n = 10), and severe left ventricular outflow tract obstruction (LVOTO, n = 10). During corrective surgery IAC was closed (group-I, n = 37) or partially left-open (group-II, n = 16). Primary endpoints were hospital death, and re-intervention (surgery and/or balloon) due to aortic arch re-coarctation or recurrent LVOTO. Statistically significant variables by univariate analysis were incorporated in the corresponding multivariable regression model.

Results

Regarding morphological discrepancies more patients in group-II presented with LVOTO (p = 0.05), or the combination of arch hypoplasia, intact ventricular septum and normal ventriculo-arterial connection (p = 0.017). Hospital mortality was 8.1% in group-I and 37.5% in group-II (p = 0.016). Re-intervention was performed in 13 patients (group-I: n = 6 vs. group-II: n = 7) due to aortic arch re-coarctation (n = 12) and/or recurrent LVOTO (n = 3), and resulted in a Kaplan-Meier freedom from re-intervention of 87 ± 6% and 79 ± 8% in group-I, and 64 ± 14% and 64 ± 14% in group-II after 1 and 5 years, respectively (p = 0.016). Multivariate analysis revealed LVOTO as an independent risk factor for hospital death (p = 0.042), whereas both LVOTO and left-open IAC (p = 0.001 and 0.01) were independent risk factors for re-intervention.

Conclusions

A left-open IAC increases risk of re-intervention at the left heart aorta complex. Sustained left-to-right shunting on atrial level seems to induce preload reduction of the often restrictive left ventricle leading to decreased aortic blood flow.

Feasibility and safety of biventricular repair in neonates with hypoplastic left heart complex

Hypoplastic left heart syndrome is a spectrum of structural cardiac malformations characterized by variable underdevelopment of the left heart-aorta complex. A minority of patients having a milder degree of left ventricular hypoplasia, described as hypoplastic left heart complex (HLHC), may be selected for biventricular repair. The objective of this study was to assess the outcome of the biventricular approach in HLHC. We evaluated retrospectively 30 neonates diagnosed with HLHC from the "12 de Octubre" University Hospital, following established criteria. We analyzed the echocardiographic data recorded just after birth and at last follow-up after surgery. All patients were operated on in the neonatal period using various surgical techniques. There were no early deaths and only 1 late death after a mean follow-up of 62.9 ± 43.8 months. All patients presented a significant growth of the left ventricular structures, with a Z-score increase of 1.17 ± 1.05 for mitral annulus, 1.72 ± 1.23 for aortic annulus, and 1.33 ± 1.46 for left ventricular end-diastolic diameter. Postoperatively, 18 patients showed a left valvular stenosis, and 17 patients underwent a reoperation and/or an interventional procedure. Freedom from surgery or interventional catheterizations at 1, 3 and 5 years was 53, 49 and 43%, respectively. The 29 current survivors are all in a good functional status. In our experience, we achieved good results from biventricular repair in patients with HLHC, with a significant growth of left heart structures and an excellent clinical status at a medium-term follow-up. Nevertheless, there was a high rate of reoperations and/or interventional catheterizations.

Usefulness of transthoracic echocardiography to accurately diagnose recoarctation of the aorta after the Norwood procedure

Recoarctation of the aorta (RCoA) is a major cause of morbidity and mortality after the Norwood procedure. We sought to identify transthoracic echocardiographic (TTE) indexes associated with RCoA and to develop a highly sensitive and specific diagnostic score for accurate diagnosis. All subjects who underwent a Norwood procedure from December 2005 to December 2009 were identified. Subjects were excluded if they did not undergo a TTE within 1 month of an outcome-defining event (cardiac catheterization, autopsy, or surgery). RCoA was defined as arch intervention at catheterization or surgery or findings of RCoA at autopsy. Of 113 subjects included for analysis, RCoA occurred in 19 (17%). All TTE indexes were significantly associated with RCoA in univariate testing. In the final multivariate model, peak isthmus velocity >2.5 m/s (p <0.001), coarctation index, defined as the ratio of the narrowest region of the descending thoracic aorta to the distal descending thoracic aorta diameter <0.7 (p <0.01), and decrease in ventricular systolic performance (p = 0.03) were all significantly associated with RCoA. A composite score was developed using a peak velocity of >2.5 m/s (2 points), coarctation index <0.7 (1 point), and a decrease in ventricular systolic performance (1 point). A score of ≥2 diagnosed RCoA with 100% sensitivity and 85% specificity. The score performed equally well regardless of shunt type. In conclusion, a composite score of TTE indexes accurately discriminates RCoA in patients who have undergone the Norwood procedure.

Comparability of Z-score equations of cardiac structures in hypoplastic left heart complex

BACKGROUND

Hypoplastic left heart complex (HLHC) is characterized by a mitral valve or an aortic valve annular Z score < -2, antegrade flow in the ascending aorta, ductal dependency, coarctation or aortic arch hypoplasia, and absence of significant (sub)valvar stenosis. The Z scores of the mitral and aortic valve annuli are major determinants of HLHC. Therefore, the algorithm for Z-score calculation is essential for diagnosis. However, no single universal method of calculation is in use. In the scientific literature addressing HLHC, various Z-score calculation methods have been applied. The aim of this study was to evaluate Z scores derived from two-dimensional echocardiographic dimensions in patients with HLHC.

METHODS

To compare the different published methods using two-dimensional echocardiographic measures for Z-score calculation, a cohort of 18 newborns diagnosed with HLHC was retrospectively evaluated. In addition, the methods to determine body surface area in newborns were evaluated.

RESULTS

Three Z-score calculation methods were included and compared. Using the method of Daubeney et al. to calculate Z scores in our cohort illustrated a lack of correlation beyond a Z score < 0, compared with the methods of Zilberman et al. and Pettersen et al. Z scores calculated using Zilberman et al.'s and Pettersen et al.'s methods were fairly consistent. The equations used by Pettersen et al. are based on the largest population of neonates.

CONCLUSION

Although the different methods for calculating Z scores for mitral and aortic valve dimensions correspond fairly well in the normal range, Z scores < -2 diverge substantially. A useful scientific comparison of published data and outcomes of patients with HLHC remains elusive. The Z-score calculation algorithms used by Pettersen et al. appear to be the most appropriate for use in an evaluation of HLHC. Because these different methods can yield different values, reporting the method as well as the Z score is essential for an accurate diagnosis. Similarly, the method used to determine body surface area should be reported.

[Congenital heart defects of the septa, endocardial cushions and the conotruncus]

During embryological development the heart develops from a simple tube into a complex fully developed heart with four chambers. Hence all congenital heart defects develop before the ninth week of gestation. Currently a steadily increasing number of genetic mutations have been found to be responsible for congenital heart defects. Nevertheless, up to now it has been impossible to diagnose a heart defect just on the basis of molecular pathology. Despite the current excellent prenatal and postnatal ultrasound diagnostics, the post-mortem examination is still the gold standard for the diagnosis of complex heart malformations. However, this requires knowledge of the pathomorphology of the heart malformation in question. Therefore, characteristic and distinguishing features of septal defects including atrioventricular septal defects are presented, especially as the latter are part of complex heart defects, such as conotruncal heart malformations.

Subjective evaluation of right ventricular systolic function in hypoplastic left heart syndrome: how accurate is it?

Background

The geometry and heterogeneity of the right ventricle in hypoplastic left heart syndrome makes objective echocardiographic assessment of systolic function challenging. Consequently, subjective echocardiographic assessment of right ventricular (RV) function is still routinely undertaken. The aims of this study were to compare this with magnetic resonance imaging (MRI), investigate the impact of experience and training on the accuracy of subjective assessment, and critically analyze the role of echocardiography to detect impaired systolic function.

Methods

A retrospective analysis of prospectively acquired data was performed. Children with hypoplastic left heart syndrome underwent routine preoperative cardiac MRI and echocardiography under the same general anesthetic. Echocardiograms were reviewed, and members of the congenital heart disease team with differing echocardiography experience subjectively graded RV systolic function (good, moderate, or poor). This was compared with MRI-derived ejection fraction.

Results

Twenty-eight patients at different palliative stages were included. Twenty-eight observers were divided into five experience categories (congenital heart disease junior trainees to attending cardiologists). Median agreement was 47.6% (range, 31.4%–58.2%), with the lowest agreement among junior trainees and the highest among attending cardiologists. When used as a screening test for poor RV systolic function, the median sensitivity of echocardiography was 0.89 (range, 0.86–0.96), and median specificity was 0.45 (range, 0.26–0.55). The highest sensitivity was observed among junior trainees but with the lowest specificity. The highest specificity was observed among attending cardiologists (0.55).

Conclusions

Agreement between echocardiographic and MRI RV ejection fraction improves with experience but remains suboptimal. When used as a screening test for poor RV function, echocardiography is sensitive, but specificity is heavily influenced by operator experience.

Disturbed myocardial connexin 43 and N-cadherin expressions in hypoplastic left heart syndrome and borderline left ventricle

OBJECTIVES

Borderline left ventricle is the left ventricular morphology at the favorable end of the hypoplastic left heart syndrome. In contrast to the severe end, it is suitable for biventricular repair. Wondering whether it is possible to identify cases suitable for biventricular repair from a developmental viewpoint, we investigated the myocardial histology of borderline and severely hypoplastic left ventricles.

METHODS

Postmortem specimens of neonatal, unoperated human hearts with severe hypoplastic left heart syndrome and borderline left ventricle were compared with normal specimens and hearts from patients with transposition of the great arteries. After tissue sampling of the lateral walls of both ventricles, immunohistochemical and immunofluorescence stainings against cardiac troponin I, N-cadherin, and connexin 43, important for proper cardiac differentiation, were done.

RESULTS

All severely hypoplastic left hearts (7/7) and most borderline left ventricle hearts (4/6) showed reduced sarcomeric expressions of troponin I in left and right ventricles. N-cadherin and connexin 43 expressions were reduced in intercalated disks. The remaining borderline left ventricle hearts (2/6) were histologically closer to control hearts.

CONCLUSIONS

Four of 6 borderline left ventricle hearts showed myocardial histopathology similar to the severely hypoplastic left hearts. The remainder were similar to normal hearts. Our results and knowledge regarding the role of epicardial-derived cells in myocardial differentiation lead us to postulate that an abnormal epicardial-myocardial interaction could explain the observed histopathology. Defining the histopathologic severity with preoperative myocardial biopsy samples of hearts with borderline left ventricle might provide a diagnostic tool for preoperative decision making.

Successful hybrid stage I palliation for hypoplastic left heart syndrome in a developing nation

The first successful stage I palliation for hypoplastic left heart syndrome (HLHS) in a four-day-old female in the Philippines is reported, along with a discussion of the particular dynamics and challenges of performing this kind of surgery in a developing nation. Challenges met were not limited to the preoperative and perioperative period but involved the interstage period as well. In the face of such challenges, our experience, reported here, is the cause for cautious optimism.

Myocyte proliferation in the developing heart

Regulation of organ growth is critical during embryogenesis. At the cellular level, mechanisms controlling the size of individual embryonic organs include cell proliferation, differentiation, migration, and attrition through cell death. All these mechanisms play a role in cardiac morphogenesis, but experimental studies have shown that the major determinant of cardiac size during prenatal development is myocyte proliferation. As this proliferative capacity becomes severely restricted after birth, the number of cell divisions that occur during embryogenesis limits the growth potential of the postnatal heart. We summarize here current knowledge concerning regional control of myocyte proliferation as related to cardiac morphogenesis and dysmorphogenesis. There are significant spatial and temporal differences in rates of cell division, peaking during the preseptation period and then gradually decreasing toward birth. Analysis of regional rates of proliferation helps to explain the mechanics of ventricular septation, chamber morphogenesis, and the development of the cardiac conduction system. Proliferation rates are influenced by hemodynamic loading, and transduced by autocrine and paracrine signaling by means of growth factors. Understanding the biological response of the developing heart to such factors and physical forces will further our progress in engineering artificial myocardial tissues for heart repair and designing optimal treatment strategies for congenital heart disease.

Report From The International Society for Nomenclature of Paediatric and Congenital Heart Disease

Tremendous progress has been made in the field of pediatric heart disease over the past 30 years. Although survival after heart surgery in children has improved dramatically, complications still occur, and optimization of outcomes for all patients remains a challenge. To improve outcomes, collaborative efforts are required and ultimately depend on the possibility of using a common language when discussing pediatric and congenital heart disease. Such a universal language has been developed and named the International Pediatric and Congenital Cardiac Code (IPCCC). To make the IPCCC more universally understood, efforts are under way to link the IPCCC to pictures and videos. The Archiving Working Group is an organization composed of leaders within the international pediatric cardiac medical community and part of the International Society for Nomenclature of Paediatric and Congenital Heart Disease ( www.ipccc.net ). Its purpose is to illustrate, with representative images of all types and formats, the pertinent aspects of cardiac diseases that affect neonates, infants, children, and adults with congenital heart disease, using the codes and definitions associated with the IPCCC as the organizational backbone. The Archiving Working Group certifies and links images and videos to the appropriate term and definition in the IPCCC. These images and videos are then displayed in an electronic format on the Internet. The purpose of this publication is to report the recent progress made by the Archiving Working Group in establishing an Internet-based, image encyclopedia that is based on the standards of the IPCCC.

Congenital heart surgery databases around the world: do we need a global database?

The question posed in the title of this article is: "Congenital Heart Surgery Databases Around the World: Do We Need a Global Database?" The answer to this question is "Yes and No"! Yes--we need to create a global database to track the outcomes of patients with pediatric and congenital heart disease. No--we do not need to create a new "global database." Instead, we need to create a platform that allows for the linkage of currently existing continental subspecialty databases (and continental subspecialty databases that might be created in the future) that will allow for the seamless sharing of multi-institutional longitudinal data across temporal, geographical, and subspecialty boundaries. This review article will achieve the following objectives: (A) Consider the current state of analysis of outcomes of treatments for patients with congenitally malformed hearts. (B) Present some principles that might make it possible to achieve life-long longitudinal monitoring and follow-up. (C) Describe the rationale for the creation of a Global Federated Multispecialty Congenital Heart Disease Database. (D) Propose a methodology for the creation of a Global Federated Multispecialty Congenital Heart Disease Database that is based on linking together currently existing databases without creating a new database. To perform meaningful multi-institutional analyses, any database must incorporate the following six essential elements: (1) Use of a common language and nomenclature. (2) Use of a database with an established uniform core dataset for collection of information. (3) Incorporation of a mechanism to evaluate the complexity of cases. (4) Implementation of a mechanism to assure and verify the completeness and accuracy of the data collected. (5) Collaboration between medical and surgical subspecialties. (6) Standardization of protocols for life-long longitudinal follow-up. Analysis of outcomes must move beyond recording 30-day or hospital mortality, and encompass longer-term follow-up, including cardiac and non-cardiac morbidities, and importantly, those morbidities impacting health-related quality of life. Methodologies must be implemented in our databases to allow uniform, protocol-driven, and meaningful long-term follow-up. We need to create a platform that allows for the linkage of currently existing continental subspecialty databases (and continental subspecialty databases that might be created in the future) that will allow for the seamless sharing of multi-institutional longitudinal data across temporal, geographical, and subspecialty boundaries. This "Global Federated Multispecialty Congenital Heart Disease Database" will not be a new database, but will be a platform that effortlessly links multiple databases and maintains the integrity of these extant databases. Description of outcomes requires true multi-disciplinary involvement, and should include surgeons, cardiologists, anesthesiologists, intensivists, perfusionists, neurologists, educators, primary care physicians, nurses, and physical therapists. Outcomes should determine primary therapy, and as such must be monitored life-long. The relatively small numbers of patients with congenitally malformed hearts requires multi-institutional cooperation to accomplish these goals. The creation of a Global Federated Multispecialty Congenital Heart Disease Database that links extant databases from pediatric cardiology, pediatric cardiac surgery, pediatric cardiac anesthesia, and pediatric critical care will create a platform for improving patient care, research, and teaching related to patients with congenital and pediatric cardiac disease.

Differential changes in TGF-β/BMP signaling pathway in the right ventricular myocardium of newborns with hypoplastic left heart syndrome

BACKGROUND

Hypoplastic left heart syndrome (HLHS) is characterized by underdevelopment of the left ventricle (LV) and increased biomechanical stress on the right ventricle (RV) from single ventricle physiology. Despite the clinical significance, the signaling pathways active during RV remodeling and disease progression are not known. To address this, we examined differential changes in expression of genes associated with transforming growth factor-beta (TGF-beta)/bone morphogenetic protein (BMP) signaling in RV tissue isolated from HLHS patients relative to RV and LV tissue from control subjects.

METHODS AND RESULTS

Quantitative real-time polymerase chain reaction was used to detect changes in expression of 84 genes involved in TGF-beta/BMP-mediated cardiac development, cell growth, and differentiation in RV tissue collected from 6 neonates with HLHS undergoing stage 1 Norwood procedure (age, 1-7 days; mean, 4 days) and RV and LV tissue obtained from 5 infants with noncardiac pathology (age range, 1-135 days: mean, 85 days) that served as controls. Analysis of gene expression profiles between control-LV and control-RV revealed significant depression of TGF-beta/BMP signaling in RV compared with LV. Of the 84 genes analyzed, 38 were differentially expressed between HLHS-RV and control-RV, whereas only 22 compared with control-LV. Significant changes were observed in: tissue remodeling genes including Activin receptor type IIA (ACVR2A) (+2.13) and Activin receptor-like kinase 1 (ACVRL1) (+2.22); and cell survival, growth, and differentiation genes including CDC25A (+2.18), p21 (-3.64), p15 (+2.15), BMP5 (+4.58), BMP3 (+2.16), GDF3 (+8.59), NODAL (+2.32), and BMP binding endothelial regulator (BMPER) (+4.58). The most significant changes common to HLHS-RV versus control-RV and control-LV sample groups is observed for Anti müllerian hormone receptor 2 (AMHR2) (+18.79 control-RV, +3.38 control-LV), and the BMP antagonist Inhibin alpha (INHA) (+11.47 control-RV, +5.73 control-LV).

CONCLUSIONS

Although this descriptive study does not allow cause-effect inferences, our results suggest changes in cardiac development pathways and upregulation of genes associated with cell growth and differentiation in the neonatal RV of children with HLHS. These molecular profiles are more closely related to those observed in the normal LV rather than normal RV at similar maturational age. This work provides the basis for future mechanistic studies to elucidate the molecular mechanisms regulating RV remodeling in HLHS.

Attitudes and practices of cardiologists and surgeons who manage HLHS

OBJECTIVE

We conducted a survey to determine which management options pediatric cardiologists and cardiac surgeons in North America discuss and recommend when counseling parents after the diagnosis of hypoplastic left heart syndrome (HLHS).

METHODS

Pediatric cardiologists and cardiac surgeons across North America were asked to complete an anonymous, Internet-based survey about their attitudes and practices regarding the management of HLHS.

RESULTS

We contacted 1621 pediatric cardiologists and surgeons, of whom 749 (46%) completed the survey. When counseling parents of newborns with HLHS, 99.7% of respondents discussed staged palliative surgery, 67% discussed cardiac transplantation, and 62.2% discussed compassionate care without surgery. Only a minority (14.9%) discussed all of those options. Staged palliative surgery was recommended over cardiac transplantation or compassionate care without surgery by 76.2% of respondents. When counseling parents after prenatal diagnosis of HLHS, 98.8% of respondents discussed continuation of pregnancy with staged palliative surgery after birth, 53.5% discussed continuation of pregnancy with cardiac transplantation after birth, 56.9% discussed continuation of pregnancy with compassionate care after birth, and 74.3% discussed termination of pregnancy. Only 36.5% discussed all of those options. Continuation of pregnancy with staged palliative surgery after birth was recommended over the other options by 56% of respondents.

CONCLUSIONS

Virtually all North American pediatric cardiologists and cardiac surgeons surveyed discuss a surgical intervention when counseling parents about the care of their child or fetus with HLHS. However, only a minority discuss all options. Most physicians recommend staged palliative surgery for management of HLHS.

Hypoplastic left heart syndrome

Hypoplastic left heart syndrome is a rare congenital heart defect in which the left side of the heart is underdeveloped. Surgical management of hypoplastic left heart syndrome has changed the prognosis of the condition that was previously regarded as fatal. We discuss surgical strategies based on staged procedures, with the right ventricle supporting both systemic and pulmonary circulation. We also discuss other management options, such as neonatal transplantation and the recent innovation of hybrid techniques. Surgical techniques and the understanding of the pathophysiology of this condition have been at the forefront of neonatal cardiac surgery and intensive care. The management of the syndrome remains a challenge because affected children grow into adolescence and adulthood posing various new problems and demands.

Hypoplastic left heart syndrome diagnosed in fetal life: associated findings, pregnancy outcome and results of palliative surgery

OBJECTIVES

To analyze the main prenatal characteristics of hypoplastic left heart syndrome (HLHS), its association with extracardiac anomalies including increased nuchal translucency (NT) and the outcome of affected patients.

METHODS

We searched our database for classical forms of HLHS (aortic atresia, mitral and aortic atresia and critical aortic stenosis evolved to a severely hypoplastic left ventricle) prenatally diagnosed between 1998 and 2006. Data on 101 fetuses were retrieved and analyzed.

RESULTS

The main reason for referral was suspected heart defect on a routine ultrasound scan (82%). The mean gestational age at diagnosis was 21 weeks. Most cases were detected at < or = 22 weeks (72%), the upper limit for termination of pregnancy (TOP) in our country (Spain). An intact atrial septum was diagnosed in 11 of the 58 fetuses (19%) in which pulmonary vein blood flow was assessed, and this diagnosis was proved to be correct in the six liveborn babies. Most fetuses (68%) had an isolated HLHS. Fourteen fetuses (14%) were chromosomally abnormal and all had associated extracardiac defects. NT was above the 95th centile in 21 of the 74 cases (28%) in which this measurement was available. 79% (58/73) of the cases in which HLHS was detected at < or = 22 weeks were terminated, and no differences in the rate of TOP were found through the study period. Among the 43 continuing pregnancies, seven fetuses died in utero and there were 36 live births; in 12 cases the parents opted for compassionate care and 24 chose to have the infant surgically treated. In the cohort of intention-to-treat cases, the overall survival rate was 36% (9/25). This rate improved from 18% (2/11) in the period 1998-2002 to 50% (7/14) in 2003-2006. There were no survivors in cases with intact atrial septum or when there were associated defects. At follow-up, 2/9 survivors suffered from significant neurological morbidity.

CONCLUSIONS

Fetal echocardiography allows an accurate diagnosis of HLHS, which is made in most instances in the first half of pregnancy. Despite the advantage offered by the prenatal detection of HLHS, which provides the opportunity to plan perinatal management, our up-to-date results show that the outlook for these fetuses is still poor, and highlight the importance of presenting these figures when counseling parents with affected fetuses.

Nomenclature and databases for the surgical treatment of congenital cardiac disease--an updated primer and an analysis of opportunities for improvement

This review discusses the historical aspects, current state of the art, and potential future advances in the areas of nomenclature and databases for the analysis of outcomes of treatments for patients with congenitally malformed hearts. We will consider the current state of analysis of outcomes, lay out some principles which might make it possible to achieve life-long monitoring and follow-up using our databases, and describe the next steps those involved in the care of these patients need to take in order to achieve these objectives. In order to perform meaningful multi-institutional analyses, we suggest that any database must incorporate the following six essential elements: use of a common language and nomenclature, use of an established uniform core dataset for collection of information, incorporation of a mechanism of evaluating case complexity, availability of a mechanism to assure and verify the completeness and accuracy of the data collected, collaboration between medical and surgical subspecialties, and standardised protocols for life-long follow-up. During the 1990s, both The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons created databases to assess the outcomes of congenital cardiac surgery. Beginning in 1998, these two organizations collaborated to create the International Congenital Heart Surgery Nomenclature and Database Project. By 2000, a common nomenclature, along with a common core minimal dataset, were adopted by The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons, and published in the Annals of Thoracic Surgery. In 2000, The International Nomenclature Committee for Pediatric and Congenital Heart Disease was established. This committee eventually evolved into the International Society for Nomenclature of Paediatric and Congenital Heart Disease. The working component of this international nomenclature society has been The International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, also known as the Nomenclature Working Group. By 2005, the Nomenclature Working Group crossmapped the nomenclature of the International Congenital Heart Surgery Nomenclature and Database Project of The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons with the European Paediatric Cardiac Code of the Association for European Paediatric Cardiology, and therefore created the International Paediatric and Congenital Cardiac Code, which is available for free download from the internet at [http://www.IPCCC.NET]. This common nomenclature, the International Paediatric and Congenital Cardiac Code, and the common minimum database data set created by the International Congenital Heart Surgery Nomenclature and Database Project, are now utilized by both The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons. Between 1998 and 2007 inclusive, this nomenclature and database was used by both of these two organizations to analyze outcomes of over 150,000 operations involving patients undergoing surgical treatment for congenital cardiac disease. Two major multi-institutional efforts that have attempted to measure the complexity of congenital heart surgery are the Risk Adjustment in Congenital Heart Surgery-1 system, and the Aristotle Complexity Score. Current efforts to unify the Risk Adjustment in Congenital Heart Surgery-1 system and the Aristotle Complexity Score are in their early stages, but encouraging. Collaborative efforts involving The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons are under way to develop mechanisms to verify the completeness and accuracy of the data in the databases. Under the leadership of The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease, further collaborative efforts are ongoing between congenital and paediatric cardiac surgeons and other subspecialties, including paediatric cardiac anaesthesiologists, via The Congenital Cardiac Anesthesia Society, paediatric cardiac intensivists, via The Pediatric Cardiac Intensive Care Society, and paediatric cardiologists, via the Joint Council on Congenital Heart Disease and The Association for European Paediatric Cardiology. In finalizing our review, we emphasise that analysis of outcomes must move beyond mortality, and encompass longer term follow-up, including cardiac and non cardiac morbidities, and importantly, those morbidities impacting health related quality of life. Methodologies must be implemented in these databases to allow uniform, protocol driven, and meaningful, long term follow-up.