Hypoplastic left heart syndrome is a severe congenital defect involving underdeveloped left-sided cardiac structures, leading to significant mortality and morbidity. Prenatal diagnosis using fetal ultrasound and echocardiography enables early detection, family counseling, and improved clinical decision-making. Advanced prenatal interventions, such as fetal aortic valvuloplasty and atrial septostomy, show promise but require careful patient selection. A multidisciplinary approach involving obstetricians, neonatologists, and pediatric cardiologists is vital for effective management. Future directions include refining imaging techniques, such as three-dimensional ultrasound, cardiovascular magnetic resonance imaging, and exploring bioengineering solutions, stem cell therapies, and genetic research. These advancements aim to improve therapeutic options and address current limitations, including transplant scarcity and postoperative complications. Although surgical innovations have improved survival rates, challenges remain, including neurological risks and long-term hemodynamic issues. Ongoing research and technological advancements are essential to enhance outcomes and quality of life for hypoplastic left heart syndrome patients.

Single ventricle (SV) anomalies account for one-fourth of all congenital heart disease cases. The existing palliative treatment for this anomaly achieves a survival rate of only 50%. To reduce the trauma associated with surgical management, the hybrid comprehensive stage II (HCSII) operation was designed as an alternative for a select subset of SV patients with the adequate antegrade aortic flow. This study aims to provide better insight into the hemodynamics of HCSII patients utilizing a multiscale Computational Fluid Dynamics (CFD) model and a mock flow loop (MFL). Both 3D-0D loosely coupled CFD and MFL models have been tuned to match baseline hemodynamic parameters obtained from patient-specific catheterization data. The hemodynamic findings from clinical data closely match the in-vitro and in-silico measurements and show a strong correlation (r = 0.9). The geometrical modification applied to the models had little effect on the oxygen delivery. Similarly, the particle residence time study reveals that particles injected in the main pulmonary artery (MPA) have successfully ejected within one cardiac cycle, and no pathological flows were observed.

Since 1988, 82 heart transplants have been performed in 80 infants and children. Diagnoses pretransplant were: hypoplastic left heart syndrome (HLHS) (n = 43); cardiomyopathy (n = 19); endocardial fibroelastosis (n = 6); and other complex congenital heart diseases (n = 12). Age at transplantation was < 1 yr in 61 patients. Overall survival rate was 79% at 1 yr and 73% at 5 and 10 yr. To date, 20 patients have died after transplantation. Causes of death were: rejection (eight patients); right ventricular failure (four patients); transplant coronary artery disease (TCAD) (two patients); and other causes (six patients). In the majority of patients somatic growth is not impaired, and renal function is reduced (but stable) in all patients. Two patients developed post-transplant lymphoproliferative disease, which was treated successfully. Major long-term morbidity is neurologic deficit - severe in three patients and minor in six. TCAD was present or suspected in six surviving patients. We conclude that heart transplantation in infants and children can be performed with good early and late results. Quality of life is excellent in most patients. TCAD, however, will become an increasing problem in the long term.

Our study was designed to characterize the patterns of growth, in the medium term, of children with functionally univentricular hearts managed with a hemi-Fontan procedure in infancy, followed by a modified Fontan operation in early childhood. Failure of growth is common in patients with congenital cardiac malformations, and may be related to congestive heart failure and hypoxia. Repair of simple lesions appears to reverse the retardation in growth. Palliation of the functionally single ventricular physiology with a staged Fontan operation reduces the adverse effects of hypoxemia and prolonged ventricular volume overload. The impact of this approach on somatic growth is unknown. Retrospectively, we reviewed the parameters of growth of all children with functionally univentricular hearts followed primarily at our institution who had completed a staged construction of the Fontan circulation between January 1990 and December 1995. Measurements were available on all children prior to surgery, and annually for three years following the Fontan operation. Data was obtained on siblings and parents for comparative purposes. The criterions of eligibility for inclusion were satisfied by 65 patients. The mean Z score for weight was -1.5 +/- 1.2 at the time of the hemi-Fontan operation. Weight improved by the time of completion of the Fontan circulation (-0.91 +/- 0.99), and for the first two years following the Fontan operation, but never normalized. The mean Z scores for height at the hemi-Fontan and Fontan operations were -0.67 +/- 1.1 and -0.89 +/- 1.2 respectively. At most recent follow-up, with a mean age of 6.1 +/- 1.3 years, and a mean time from the Fontan operation of 4.4 +/- 1.4 years, the mean Z score for height was -1.15 +/- 1.2, and was significantly less than comparable Z scores for parents and siblings. In our experience, children with functionally univentricular hearts who have been palliated with a Fontan operation are significantly underweight and shorter than the general population and their siblings.

Few congenital heart malformations have raised as many surgical, ethical, social and economic issues as the therapy for infants diagnosed with hypoplastic left heart syndrome. Before the 1980s, this complex malformation was associated with 95% mortality within the first month of life. In the past two decades, palliative surgery and cardiac transplantation have become management options, in addition to comfort care for the infant. These innovations have forced parents and physicians to make difficult decisions because the long term results of the additional treatment options are not known. This article describes the current risk factors, diagnosis, treatment and outcome of infants with hypoplastic left heart syndrome. Prenatal diagnosis provides families with time for counselling and for becoming more informed about management options. Surgical therapy provides hope for the survival of these infants, but their long term outcomes are not well defined. Comfort care in either the home or hospital remains an acceptable management option. More investigations to determine the long term outcome following palliative surgery and transplantation are needed before they become the standards of care.

Once considered a uniformly fatal condition, the outlook for newborns with hypoplastic left heart syndrome has been dramatically improved with either a protocol of staged reconstruction or cardiac transplantation. Currently, a significant shortage of suitable donor hearts restricts the applicability of transplantation for most newborns. At the University of Michigan, we have adopted a policy of staged reconstruction for all patients with hypoplastic left heart syndrome, reserving transplantation only for those unsuitable for reconstructive techniques. Between January 1990 and September 1998, 303 patients underwent the Norwood operation for classic hypoplastic left heart syndrome with an overall hospital survival of 76%. Among patients considered at standard risk, survival was significantly higher (86%) than that for those patients with important risk factors (42%), p = 0.0001. Adverse survival was most strongly associated with significant associated noncardiac congenital conditions (p = 0.008) and severe preoperative obstruction to pulmonary venous return (p = 0.03). Survival following second stage reconstruction with a hemi-Fontan or bidirectional Glenn procedure was 98%. The Fontan procedure has been completed in 117 of these patients with a hospital survival rate of 91%. Survival after the Fontan procedure improved significantly when the second stage of the reconstruction was completed with a hemi-Fontan procedure compared to a bidirectional Glenn, 98% vs 81%, p < .05. Among the patients considered at standard risk, actuarial survival was 70% at 5 years. The largest decrease in survival occurred in the first month of life and late deaths affected primarily those patients in the high risk group. Neurodevelopmental outcome studies demonstrated normal verbal and performance scores in the majority of patients. Among centers utilizing a protocol of transplantation, donor organ shortages have resulted in a mortality of approximately 25% while awaiting transplantation with 5 year survival rates for those actually receiving organs essentially equal to those for staged reconstruction. Staged reconstruction and transplantation have significantly improved the intermediate-term outlook for patients with hypoplastic left heart syndrome. Factors addressing improvements in early first stage survival following the Norwood would be expected to add significantly to an overall improved late outcome. Outcome following cardiac transplantation is limited by donor availability in addition to the late complications of infection, rejection, graft atherosclerosis, and lymphoproliferative disease.

We have empirically used supplemental nitrogen in newborns with a functional single ventricle and ductal-dependent systemic perfusion to prevent pulmonary vasodilation and deliver a greater proportion of flow to the systemic circulation. Thus, we reviewed patient outcome to determine whether adverse pulmonary vascular effects may be associated with this therapy.

From December 1991 to December 1995, the fraction of inspired oxygen was adjusted, with supplemental nitrogen if necessary, to maintain an oxygen saturation near 75% in 20 newborns awaiting heart transplantation. Medical records were reviewed to evaluate (1) the duration of nitrogen therapy, (2) pulmonary vascular histology, (3) postoperative pulmonary hemodynamics, and (4) survival.

Thirteen patients underwent heart transplantation, 4 patients died without surgical intervention, and 3 patients underwent late aortic reconstruction. Supplemental nitrogen was used without exceeding a fraction of inspired oxygen of 0.21 for 38 +/- 6 days. One patient had evidence of changes of potentially irreversible pulmonary vascular disease. Pulmonary vascular resistance was not increased long-term in surviving patients.

Supplemental nitrogen can be used to maintain a systemic oxygen saturation near 75% for an extended period in newborns with ductal-dependent systemic perfusion with no long-term adverse effect on pulmonary vascular resistance.