Management Of Hypoplastic Left Heart Syndrome Research Articles

Hybrid stage 1 palliation for HLHS: the experience of a tertiary center in a developing country.

Hypoplastic left heart syndrome (HLHS) accounts for 2.6% of congenital heart disease and is an invariably fatal cardiac anomaly if left untreated. Approximately 33,750 babies are born annually with HLHS in developing countries. Unfortunately, the majority will not survive due to the scarcity of resources and the limited availability of surgical management. To describe and analyze our experience with the hybrid approach in the management of HLHS in a developing country. We performed a retrospective single-center study involving all neonates born with HLHS over five years at the Children's Heart Center at the American University of Beirut. The medical records of patients who underwent the hybrid stage 1 palliation were reviewed, and data related to baseline characteristics, procedure details and outcomes were collected to describe the experience at a tertiary care center in a developing country. A total of 18 patients were diagnosed with HLHS over a five-year period at our institution, with male to female ratio of 1:1. Of those, eight patients underwent the hybrid stage I procedure. The mean weight at the time of the procedure was 3.3 ± 0.3 kg with an average age of 6.4 ± 4 days. The mean hospital length of stay was 27.25 days, with an interquartile range of 33 days. The cohort's follow-up duration averaged 5.9 ± 3.5 years. The surgical mortality was zero. Only one mortality was recorded during the interstage period between stage I and II and was attributed to sepsis. Notably, all surviving patients maintained preserved and satisfactory cardiac function with good clinical status. Our limited experience underscores the potential of developing countries with proper foundations to adopt the hybrid procedure for HLHS, yielding outcomes on par with those observed in developed countries. This demonstrates the viability of establishing a more balanced global landscape for children with congenital heart disease.

Bilateral pulmonary artery banding in higher risk neonates with hypoplastic left heart syndrome

ObjectivesLimited data on performing bilateral pulmonary artery banding (BPAB) before stage 1 Norwood procedure suggest that some patients may benefit through the postponement of the major cardiopulmonary bypass procedure. The objective of this study was to evaluate the effectiveness of BPAB in the surgical management of high-risk patients with hypoplastic left heart syndrome (HLHS). MethodsA retrospective review of all high-risk neonates with HLHS who underwent BPAB at our institution was performed. No patients, including those with intact or highly restrictive atrial septum (IAS), were excluded. ResultsBetween October 2015 and April 2021, 49 neonates with HLHS (including 6 with IAS) underwent BPAB, 40 of whom progressed to the Norwood procedure. Risk factors for not progressing to the Norwood procedure after BPAP include low birth weight (P = .043), the presence of multiple extracardiac anomalies (P = .005), and the presence of genetic disorders (P = .028). Operative mortality was 7.5% (3/40). IAS was associated with operative mortality (P = .022). ConclusionsThe strategy of BPAB prestage 1 Norwood procedure was successful in identifying at-risk patients and improving Norwood survival. Although not all patients will need this hybrid approach, a significant number can be expected to benefit from this tactic. These results support the need for a substantial hybrid strategy, in addition to a primary stage 1 Norwood surgical strategy, in the management of HLHS.

Recent Team experience on Norwood procedure: Conventional palliation techniques are superior

Hypoplastic left heart syndrome (HLHS) is a severe anomaly. In France prenatal diagnostic is systematically associated with proposal for pregnancy termination. However still many newborns are referred for surgical management. The aim of the present study was to evaluate our recent experience with Norwood type univentricular palliation with particular emphasis to the surgical technique used. The records of 44 consecutive patients who underwent procedure by Marie-Lannelongue and Jacques-Cartier Hospitals’ team between 2010 and 2018 were reviewed. The study group included 28 (64%) HLHS, 6 (14%) hypolplastic left heart complex, 2 (4.5%) unbalanced AV canal. Norwood-Sano procedure was performed in 29 (66%), conventional Norwood in 7 (16%). A modification of Norwood- procedure using a intravascular Aorta-pulmonaru artery separation patch with hole was performed in 6 and the remaining 2 underwent hybrid-2 stage management. Three patients who underwent conventional Norwood procedure had been managed for biventricular pathway initially however converted in single ventricle pathway. The mortality occurred in 8 (18%, 70% CL 13-25%) patients including all death until stage 2, superior cavopulmonary shunt procedure. The outcome after Norwood-Sano/conventional Norwood procedures were superior to the modified technique ( P = 0.19). From 36 survivors, 16 had their 2nd stage and 6 their 3rd stage with total cavo-pulmonary shunt procedure. Two patients were converted to biventricular repair. One patient died after 2nd stage. Despite the lack of conviction for referral, the management of HLHS and similar conditions were managed with favourable outcome. Technical modification that excludes conventional techniques, associated with poorer outcomes, must be avoided.

Regenerative medicine therapy for single ventricle congenital heart disease.

One of the most complex forms of congenital heart disease (CHD) involving single ventricle physiology is hypoplastic left heart syndrome (HLHS), characterized by underdevelopment of the left ventricle (LV), mitral and aortic valves, and narrowing of the ascending aorta. The underdeveloped LV is incapable of providing long-term systemic flow, and if left untreated, the condition is fatal. Current treatment for this condition consists of three consecutive staged palliative operations: the first is conducted within the first few weeks of birth, the second between 4 to 6 months, and the third and final surgery within the first 4 years. At the conclusion of the third surgery, systemic perfusion is provided by the right ventricle (RV), and deoxygenated blood flows passively to the pulmonary vasculature. Despite these palliative interventions, the RV, which is ill suited to provide long-term systemic perfusion, is prone to eventual failure. In the absence of satisfying curative treatments, stem cell therapy may represent one innovative approach to the management of RV dysfunction in HLHS patients. Several stem cell populations from different tissues (cardiac and non-cardiac), different age groups (adult- vs. neonate-derived), and different donors (autologous vs. allogeneic), are under active investigation. Preclinical trials in small and large animal models have elucidated several mechanisms by which these stem cells affect the injured myocardium, and are driving the shift from a paradigm based upon cellular engraftment and differentiation to one based primarily on paracrine effects. Recent studies have comprehensively evaluated the individual components of the stem cells' secretomes, shedding new light on the intracellular and extracellular pathways at the center of their therapeutic effects. This research has laid the groundwork for clinical application, and there are now several trials of stem cell therapies in pediatric populations that will provide important insights into the value of this therapeutic strategy in the management of HLHS and other forms of CHD. This article reviews the many stem cell types applied to CHD, their preclinical investigation and the mechanisms by which they might affect RV dysfunction in HLHS patients, and finally, the completed and ongoing clinical trials of stem cell therapy in patients with CHD.

Can Randomized Clinical Trials Impact the Surgical Approach for Hypoplastic Left Heart Syndrome?

The Eighth International Conference of the Pediatric Cardiac Intensive Care Society was held in Miami, Florida, December 8 to 11, 2010. The program included a session dedicated to the management of hypoplastic left heart syndrome (HLHS), with particular emphasis on the innovations that have led to contemporary schemes of management and the role of clinical trials in the evolution and acceptance of these strategies. An invited panel of experts reviewed the historical evolution of staged surgical reconstruction, the randomized clinical trials that have been undertaken thus far, and the extent to which these have, or have not, influenced individual and institutional approaches to management of HLHS.

Hybrid Therapy for Hypoplastic Left Heart Syndrome: Reality Check

Pilla et al. [2] are to be congratulated and commended for their honesty and integrity in reporting an unfavorable outcome for the new management strategy of patients with hypoplastic left heart syndrome (HLHS) in their article in this issue of Pediatric Cardiology. What is a hybrid intervention for HLHS? And why do it? Hybrid therapy refers to a collaborative effort between a cardiac surgeon and an interventional cardiologist in managing these patients. Ideally, this is conducted in a hybrid suite. Through a median sternotomy, the surgeon bands the branch pulmonary arteries (left and right), followed by stent implantation in the ductus arteriosus by the interventional cardiologist. In the event the atrial septal communication is restrictive, a stent is placed across the patent foramen ovale either percutaneously or via a peratrial route. This procedure is completed without the need for cardiopulmonary bypass. A few months later, when the infant is larger, a comprehensive stage II (Norwood) with a bidirectional Glenn anastomosis is performed. The obvious advantage of such an approach is the avoidance of a major operation with potential circulatory arrest in the immediate neonatal period with the known risks this carries on the developing brain. In addition, some believe that by postponing a major procedure until the infant is a few months of age, the mortality rate associated with the Norwood operation is reduced. Many centers throughout the world, including experienced centers in the United States, report high surgical mortality for the Norwood operation performed in the immediate neonatal period. In a study by the Congenital Heart Surgeon Society involving 29 centers and 710 neonates from 1994 to 2000, only 54% of patients with HLHS were alive after the Fontan operation [1]. Mortality continues to be high even with modifications of the Norwood, such as the Sano operation, in which a conduit is placed between the right ventricle and the main pulmonary artery. Additional complications may occur in the future after the Sano procedure secondary to right ventriculotomy. This has led some experienced surgeons to abandon this modification. With the newer innovation of the hybrid intervention, many believed that adopting this technique would result in a decreased mortality rate for HLHS. Unfortunately, this was not the case, as shown in the study of Pilla et al., in which there was a high mortality rate for their group of patients. In examining this study, I believe there are potential factors that have contributed to this unwanted outcome, including the small sample size at each site, the different postoperative management strategies for each site, and the lack of infrastructure. Even in centers with good postoperative management and strong infrastructure, the mortality rate of this new hybrid therapy is still high. The group at Nationwide Children’s Hospital in Columbus, Ohio, and our group in Chicago had to change the approach a few times until mortality was decreased with better outcome. It is perhaps advisable for centers wanting to pursue the hybrid approach to management of HLHS to collaborate with centers with well-established track records, such as the team at Columbus, and witness first hand the hybrid procedure and postoperative care that follows. This can be followed by proctoring by experienced cardiologists and surgeons, such as those from Columbus or the group in Giessen, Germany, conducted at the institution seeking to adopt this new methodology. Z. M. Hijazi (&) Rush Center for Congenital & Structural Heart Disease, Rush University Medical Center, Jones 770, 1653 W. Congress Parkway, Chicago, IL 60612, USA e-mail: zhijazi@rush.edu

Preoperative management of hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is the most common functional single ventricle congenital cardiac defect. This syndrome is characterised by a functional single right ventricle and systemic outflow obstruction. The systemic and pulmonary circulations compete for cardiac output with a resultant pr-ecarious balance among systemic, pulmonary and coronary blood flows. A once fatal diagnosis, advances in operative and perioperative care have resulted in a dramatic improvement in survival. The preoperative management of neonates with HLHS is based predominately on clinical experience and extrapolated data from the postoperative literature. Management focuses on maintaining patency of the systemic outflow, balancing the p-ulmonary and systemic blood flows, and preserving the function of a single right ventricle to maximise oxygen delivery to the tissues. This paper reviews the available therapies for the preoperative management of HLHS.

Mesenteric ischemia in hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) has been widely viewed as a uniformly fatal form of congenital heart disease. Between January 1984 and December 1990, 387 patients with the diagnosis of HLHS were treated at this institution. Mesenteric ischemia was clinically diagnosed in 31 patients (8% incidence) and confirmed by pathology or surgery in 25 of those patients. The mean age at the time of onset was 17.5 ± 5.4 weeks and only 13% were premature newborns. In 80% of the patients a low perfusion state and significant hypotension were documented within 48 hours prior to the diagnosis of bowel ischemia. Nine patients (29%) required operative intervention (bowel resection 4, diffuse ischemia 3, and simple drainage 2). Overall, at operation or at autopsy, nine patients (29%) had diffuse gastrointestinal ischemia. Of 31 patients with mesenteric ischemia, 26 children (84%) died shortly after onset of the gastrointestinal symptoms regardless of means of management. Five patients (10%) initially improved with aggressive medical and/or surgical management; however, 4 subsequently died secondary to complications of their primary cardiac disease. Therefore, the overall mortality of patients with mesenteric ischemia was 97%. Previous reports have estimated that up to 7% of full-term newborns with symptomatic congenital heart disease may develop necrotizing enterocolitis (NEC). Our unique group of patients with HLHS is comprised mostly of full-term infants who developed onset of mesenteric ischemia at a mean age of 4 months associated with an underlying low perfusion state. This mesenteric ischemia has been erroneously identified as NEC. These data suggest that this condition and patient population are distinct from that of NEC and should be labeled “mesenteric ischemia of childhood” (MIC). NEC and MIC may share some common pathological and clinical features but are distinctly different disease processes. Currently, there are no data available regarding the development of MIC in infants with systemic low perfusion. In this first reported series of HLHS patients with MIC the problem is almost uniformly fatal. Although advances in the management of HLHS have changed the prognosis of this fatal disease to over 50% survival rate, it has resulted in the development of a new clinical challenge that must be recognized by pediatric surgeons in order to improve patient outcome. Early and aggressive intervention must be used if survival is to be optimized.