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This Supplement to Cardiology in the Young represents the ninth annual supplement generated from the two meetings that compose “HeartWeek in Florida”. “HeartWeek in Florida”, the joint collaborative project sponsored by the Cardiac Center at the Children's Hospital of Philadelphia, together with All Children's Hospital of Saint Petersburg and the Congenital Heart Institute of Florida, averages over 1000 attendees every year and is now recognized as one of the major planks of continuing medical and nursing education for those working in the fields of diagnosis and treatment of cardiac disease in the fetus, neonate, infant, child, and adult. “HeartWeek in Florida” combines the International Symposium on Congenital Heart Disease, now organised by All Children's Hospital and Johns Hopkins Medicine and entering its 12th year, with the Annual Postgraduate Course in Pediatric Cardiovascular Disease organised by Children's Hospital of Philadelphia and entering its 16th year. The theme of this supplement generated from the 2011 HeartWeek in Florida is “A Holistic Approach to Hypoplastic Left Heart Syndrome and Other Evolving Challenges in Paediatric and Congenital Cardiac Disease”. We would like to acknowledge the tremendous contributions made to medicine by Martin Elliott and Gil Wernovsky; and therefore, we dedicate this HeartWeek 2011 Supplement to them.
On the basis of both developmental and morphological evidence, we would suggest that a ventricle is best defined as any chamber within the ventricular mass possessing an apical trabecular component. Such ventricles can be of right or left morphology, and always coexist. The ventricles are normally formed when possessing all three of the inlet, apical trabecular, and outlet components, but incomplete when lacking one or both of the inlet and outlet components. Ventricles that are incomplete because of lack of the inlet component are always hypoplastic, with incomplete right ventricles being positioned antero-superiorly within the ventricular mass, and incomplete left ventricles located postero-inferiorly. Patients having such incomplete ventricles because of the lack of the inlet component have functionally univentricular hearts, although the functionally univentricular arrangement can also be produced in the setting of normally constituted but hypertrophied ventricles. Full analysis of ventricular morphology, therefore, requires attention not only to component make-up, but also size.
Congenital cardiac disease is the most common birth defect, occurring in approximately 1 in 1000 live births. Congenital cardiac defects have associations, whether with gender, race, or specific chromosomal abnormalities, potentially allowing grouping of defects to be studied in an effort to develop an understanding of aetiological factors. The Baltimore-Washington Infant Study provides full ascertainment of a population of infants with congenital cardiac disease born in a defined geographic region. The fundamental hypotheses generated at the inception of the Baltimore-Washington Infant Study included the central idea that the outcome of birth, including the development of congenital cardiac malformations, was influenced by environmental factors and their route of introduction into a genetically susceptible host. Evidence exists that supports the concept that both genetic and environmental factors contribute to the development of diseases of the left heart.
Echocardiography is critical in the assessment of patients with hypoplastic left heart syndrome. Fundamental techniques and standardised approaches are useful when evaluating patients with hypoplastic left heart syndrome prenatally, after birth, and before the Norwood operation (Stage 1); after the Norwood operation, before and after the superior cavopulmonary anastomosis (Stage 2); before and after the Fontan operation (Stage 3); and for chronic surveillance after the Fontan operation. From foetal assessment to ongoing surveillance after the Fontan procedure, echocardiography remains the primary technique for cardiac monitoring in this growing population of children and adults.
The management of newborns with hypoplastic left heart syndrome has changed significantly over the past three decades, with an associated dramatic improvement in outcomes. The aim of this paper is to discuss current peri-operative and palliative surgical strategies. Owing to the fact that comparative outcomes for these strategies have been addressed in a limited number of prospective trials and extractions from multi-centred databases, the primary focus of this review is descriptive.
The hybrid approach to the treatment of patients with hypoplastic left heart syndrome most commonly includes transcatheter placement of a stent in the arterial duct and surgical placement of bands on the branch pulmonary arteries via median sternotomy. This manuscript will review the concept of hybrid palliation and discuss topics related to several time intervals: peri-procedural, post-procedural, interstage, and comprehensive stage 2.
Primary care cardiology is also known as ambulatory cardiology and outpatient cardiology. Primary care cardiology for the longitudinal management of patients with hypoplastic left heart syndrome is both poorly described and has limited evidence to justify its basis. This article briefly discusses the various complications that these patients can develop, reviews the medical literature, and describes a framework for the care of these complex patients from infancy to transition to care by specialists in adults with congenital cardiac disease.
Improvement in operative survival of patients with hypoplastic left heart syndrome has led to increasing emphasis on prevention of interstage mortality. Many centres have improved interstage results through programmes of home monitoring following discharge after the Norwood (Stage 1) operation. Experience with heightened interstage surveillance has identified failure to thrive during infancy as a modifiable risk factor for this population, one that has been linked to concerning outcomes at subsequent palliative surgeries. Ensuring normal growth as an infant has thus become a priority of management of patients with functionally univentricular hearts. Herein, we review the existing evidence for best practices in interstage surveillance and optimal nutrition in infants with functionally univentricular hearts. In addition, we highlight data presented at HeartWeek 2011, from Cardiology 2011, the 15th Annual Update on Pediatric and Congenital Cardiovascular Disease, and the 11th Annual International Symposium on Congenital Heart Disease.
Interventional cardiology plays a key role in the diagnosis and management of patients with functionally univentricular physiology after the various stages of surgical palliation. The interventions performed are widely variable in type, including angioplasty of stenotic vessels and implantation of stents in stenotic vessels; closure of defects such as collaterals, leaks in baffles, and fenestrations; creation of fenestration; and more. In the setting of venous hypertension associated with stenosis at the Fontan baffle, conduit, or pulmonary arteries, stent implantation is often preferred, as the aim is to eliminate completely the narrowing, given that relatively mild stenosis can have a significant detrimental hemodynamic effect in patients with functionally univentricular circulation. The procedure is highly successful. In patients who fail after Fontan procedure, creation of a fenestration is often performed, with variable technique depending on the underlying anatomic substrate. To increase chances of patency of the fenestration, implantation of a stent is often required, particularly in the setting of an extracardiac conduit. For those patients with cyanosis and favorable Fontan hemodynamics, closure of the fenestration is performed using atrial septal occluder devices with high success rate. Coils compatible with magnetic resonance imaging are used widely to treat collateral vessels, although on occasion other specific embolization tools are required, such as particles or vascular plugs. Postoperative arch obstruction is successfully managed with angioplasty at a younger age, while implantation of a stent in the aorta is reserved for older patients. Specifics of these interventional procedures as applied to the population of patients with functionally univentricular hearts are described in this manuscript.
Children with functionally univentricular hearts are now surviving into their third and fourth decades of life. Although survival alone is a remarkable achievement, a lot must still be done to improve the quality and duration of life after the Fontan operation. Challenges that may be faced by these patients include the impact of the Fontan operation on the liver and the density of bone, protein-losing enteropathy, and plastic bronchitis. Paediatric cardiologists are familiar with the haemodynamic issues inherent in Fontan physiology; however, training in cardiology is often not sufficient to give us a complete understanding of the pathophysiology of the complications or of the options for treatment. Collaboration with other subspecialists including gastroenterologists, endocrinologists, and pulmonologists is essential in order to provide the rigorous and nuanced care that our patients need and deserve. A clinic in which a patient can see multiple subspecialists, and in which the subspecialists, as a group, can discuss each patient, can provide a unique and valuable service for patients with a functionally univentricular heart.
Improved survival in children with hypoplastic left heart syndrome has created a sub-population of children and young adults who are living with functionally univentricular physiology. Routine surveillance with comprehensive screening for structural cardiac disease, functional cardiac disease, arrhythmias, thromboembolic disease, and associated dysfunction of end organs is important. Future directives will better define the plans of care for routine surveillance in patients with hypoplastic left heart syndrome.
The aim of this review is to describe the current state of knowledge related to neurodevelopmental outcomes and quality of life for children with hypoplastic left heart syndrome and to explore future questions to be answered for this group of children.
Hypoplastic left heart syndrome remained a largely untreated lesion until the 1980s. In the current era, 75–80% of patients who are managed at “centres of excellence” can be expected to survive into young adulthood after staged palliation. This improved survival has led to an emerging population of patients now entering adulthood with a new set of concerns. We discuss the realised and potential issues that will be faced by these patients, including family planning, transition, and re-operation.
The success of extracorporeal support in providing cardiopulmonary support for a variety of patients has led to use of Extracorporeal Life Support, also known as ECLS, as a rescue for patients failing conventional resuscitation. The use of Extracorporeal Life Support in circumstances of cardiac arrest has come to be termed “Extracorporeal Life Support during Cardiopulmonary Resuscitation” or “ECPR”. Although Extracorporeal Life Support during Cardiopulmonary Resuscitation was originally described in patients following repair of congenital cardiac defects who suffered a sudden arrest, it has now been used in a variety of circumstances for patients both with and without primary cardiac disease. Multiple centres have reported successful use of Extracorporeal Life Support during Cardiopulmonary Resuscitation in adults and children. However, because of the cost, the complexity of the technique, and the resources required, Extracorporeal Life Support during Cardiopulmonary Resuscitation is not offered in all centres for paediatric patients with refractory cardiac arrest. The increasing success and availability of Extracorporeal Life Support during Cardiopulmonary Resuscitation in post-operative cardiac patients, coupled with the fact that patients undergoing the Norwood (Stage 1) operation can have rapid, unpredictable cardiac deterioration and arrest, has led to a steady increase in the use of Extracorporeal Life Support during Cardiopulmonary Resuscitation in this population. For Extracorporeal Life Support during Cardiopulmonary Resuscitation to be most successful, it must be deployed rapidly while the patient is undergoing excellent cardiopulmonary resuscitation. Early activation of the team that will perform cannulation could possibly shorten the duration of cardiopulmonary resuscitation and might improve survival and outcome. More research needs to be done to refine the populations and circumstances that offer the best outcome with Extracorporeal Life Support during Cardiopulmonary Resuscitation, to evaluate the ratios of cost to benefit, and establish the long-term neurodevelopmental outcomes in survivors.
Extracorporeal cardiopulmonary resuscitation may be defined as the use of extracorporeal membrane oxygenation for the support of patients who do not respond to conventional cardiopulmonary resuscitation. Data from national and international paediatric databases indicate that the use of extracorporeal cardiopulmonary resuscitation is increasing. Guidelines from the American Heart Association suggest that any patient with refractory cardiopulmonary resuscitation and potentially reversible causes of cardiac arrest is a candidate for extracorporeal cardiopulmonary resuscitation. One possible framework for selection of patients for extracorporeal cardiopulmonary resuscitation includes dividing patients on the basis of favourable or unfavourable characteristics. Favourable characteristics include cardiac disease, witnessed event in the intensive care unit, ability to deliver effective cardiopulmonary resuscitation, active patient monitoring present, favourable arterial blood gases, and early institution of extracorporeal membrane oxygenation. Unfavourable characteristics potentially include non-cardiac disease, an unwitnessed cardiac arrest, ineffective cardiopulmonary resuscitation, and severely acidotic arterial blood gases. Considering the significant resources and cost involved in the use of extracorporeal cardiopulmonary resuscitation, its use needs to be critically examined to improve outcomes, assess neurological recovery and quality of life, and help identify populations and other factors that may help guide in the selection of patients for successful extracorporeal cardiopulmonary resuscitation.
The use of extracorporeal membrane oxygenation in infants and children with cardiac disease who develop refractory cardiogenic shock, cyanosis, or cardiac arrest is increasing. Early mortality in children with cardiac disease who require extracorporeal membrane oxygenation remains an important issue, as only 40% of cannulated patients survive to discharge from the hospital. However, it is encouraging that 90% children who are discharged alive from the hospital after extracorporeal membrane oxygenation are still alive at intermediate-term follow-up. Surviving patients are at risk for long-term dysfunction of multiple organ systems related to their underlying cardiac disease, non-cardiac comorbidities, treatment-related complications, and exposure to extracorporeal membrane oxygenation. Among the most important acute complications related to support with extracorporeal membrane oxygenation is injury to the central nervous system, which may contribute to adverse neurodevelopmental outcomes. All of these factors, in turn, influence quality of life. Many survivors remain medically complex related to their underlying cardiac disease, comorbidities, and sequelae of complications acquired over their lifetime. Neurological morbidity clearly plays an important role in approximately one-third of survivors, with significant deficits in approximately 10%. The limited data about quality of life data that are available for survivors of cardiac extracorporeal membrane oxygenation suggests that approximately 15–30% of survivors have at least moderately decreased quality of life. Overall, published data support the ongoing use of support with extracorporeal membrane oxygenation in children with acute cardiac failure, most of whom would die without it. However, programmatic efforts to improve the selection of patients and the preservation of the function of end organs during extracorporeal membrane oxygenation are clearly needed in order to improve long-term outcomes.
Highly sensitised children in need of cardiac transplantation have overall poor outcomes because of increased risk for dysfunction of the cardiac allograft, acute cellular and antibody-mediated rejection, and vasculopathy of the cardiac allograft. Cardiopulmonary bypass and the frequent use of blood products in the operating room and cardiac intensive care unit, as well as the frequent use of homografts, have predisposed potential recipients of transplants to allosensitisation. The expansion in the use of ventricular assist devices and extracorporeal membrane oxygenation has also contributed to increasing rates of allosensitisation in candidates for cardiac transplantation. Antibodies to Human Leukocyte Antigen can be detected before transplantation using several different techniques, the most common being the “complement-dependent lymphocytotoxicity assays”. “Solid-phase assays”, particularly the “Luminex® single antigen bead method”, offer improved specificity and more detailed information regarding specificities of antibodies, leading to improved matching of donors with recipients. Allosensitisation prolongs the time on the waiting list for potential recipients of transplantation and increases the risk of complications and death after transplantation. Aggressive reduction of antibodies to Human Leukocyte Antigen in these high-risk patients is therefore of vital importance for long-term survival of the patient and cardiac allograft. Strategies to decrease Panel Reactive Antibody or percent reactive antibody before transplantation include plasmapheresis, intravenous administration of immunoglobulin, and specific treatment to reduce B-cells, particularly Rituximab. These strategies have resulted in varying degrees of success. Antibody-mediated rejection and cardiac allograft vasculopathy are two of the most important complications of transplantation in patients with high Panel Reactive Antibody. The treatment of antibody-mediated rejection in recipients of cardiac transplants is largely empirical and includes the use of high-dose corticosteroids, plasmapheresis, intravenous administration of immunoglobulins, anti-thymocyte globulin, and Rituximab. Cardiac allograft vasculopathy is believed to be secondary to chronic complement-mediated endothelial injury and chronic vascular rejection. The use of proliferation signal inhibitors, such as sirolimus and everolimus, has been shown to delay the progression of cardiac allograft vasculopathy. In some non-sensitised recipients of cardiac transplants, the de novo formation of antibodies to Human Leukocyte Antigen after transplantation may increase the likelihood of adverse clinical outcomes. The use of serial testing for donor-specific antibodies after cardiac transplantation may be advisable in patients with frequent episodes of rejection and patients with history of sensitisation. Allosensitisation before transplantation can negatively influence outcomes after transplantation. A high incidence of antibody-mediated rejection and graft vasculopathy can result in graft failure and decreased survival. Current strategies to decrease allosensitisation have helped to expand the pool of donors, improve times on the waiting list, and decrease mortality. Centres of transplantation offering desensitisation are currently using plasmapheresis to remove circulating antibodies; intravenous immunoglobulin to inactivate antibodies; cyclophosphamide to suppress B-cell proliferation; and Rituximab to deplete B-lymphocytes. Similar approaches are also used to treat antibody-mediated rejection after transplantation with promising results.
Part 2: Ethical Considerations Associated with Caring for Patients with Hypoplastic Left Heart Syndrome
In utero diagnosis of complex progressive cardiac disease such as hypoplastic left heart syndrome presents a novel opportunity for antepartum, intrapartum, and neonatal management. The clinical possibilities and potential for differing outcomes challenge the mother–foetus dyad with regard to informed consent. Previous studies reveal that rates of termination of pregnancy for foetuses with hypoplastic left heart syndrome vary widely in the United States and Europe, leading us to surmise that informed consent may be practised differently. The purpose of this paper is to review the ethical considerations and physician responsibilities of informed consent as they relate to prenatal and postnatal patients with hypoplastic left heart syndrome. Special consideration is paid to the informed consent process as practised by the obstetrician, perinatologist, paediatric cardiologist, and paediatric cardiac surgeon as it relates to termination of pregnancy, comfort care, and surgical palliation. We will argue that informed consent as it relates to hypoplastic left heart syndrome is far from standardised and that there exists a state of bioethical equipoise concerning the extent and limits of its application in the current clinical setting.
Although recent advances have helped identify cases where foetal cardiac surgery might reverse the development of certain lesions, the indications and measurement of success in these procedures have yet to be established. Thus, both patients and physicians have a “burden of knowledge”, whereby a diagnosis is made without a clear course of action. The profound issues raised by foetal intervention, specifically the question of how concepts such as “patient” and “success” can be used, complicate this burden further and test the limits of language and logic. Similar issues raised in postmodern philosophy are discussed and can be incorporated into foetal cardiac surgery dialogues to produce a multi-disciplinary approach that will elucidate, not obfuscate, these issues in the future.
Several years ago, one of us described the difference in attitude to patients with hypoplastic left heart syndrome in the United States of America and Europe as similar to that between Mars and Venus. Uncertainty remains with regard to the long-term prognosis for patients with hypoplastic left heart syndrome. This prognosis may be considered in terms of survival, functional performance, including exercise capacity and neurodevelopment, as well as psychosocial effects on the patient, family, and siblings. Counselling parents where either an antenatal or postnatal diagnosis of hypoplastic left heart syndrome has been made requires practitioners to give information on these prognostic aspects. We wanted to see how attitudes among European surgeons have changed over the last few years.
We performed a review of recent European data for hypoplastic left heart syndrome and conducted a survey among surgeons in major European centres to ascertain key aspects of their attitudes to the management of patients with hypoplastic left heart syndrome and how they counsel parents.
Results and conclusions
As of January, 2011, 2392 citations in the PubMed database were available for the search string “hypoplastic left heart”. The majority of these were from the centres from the United States of America and Europe. The European Association for Cardio-Thoracic Surgery Congenital Heart Surgery Database shows an annual increase in the number of Norwood (Stage I) operations for hypoplastic left heart syndrome from 2003 to 2009, with a corresponding reduction in mortality. European rates of antenatal detection vary widely between centres, as do the rates of termination for a prenatal diagnosis of hypoplastic left heart syndrome. We observed a wide variation in the estimates of surgeons for survival and quality of life for surgical palliation of hypoplastic left heart syndrome, as well as in their estimates for actual rates of termination of pregnancy in their centres. Further, there was marked inconsistency in the information given to parents as part of the process of counselling. These issues remain to be resolved if parents are to make a fully informed decision for their child.