New Aspects in the Diagnosis and Therapy of Fetal Hypoplastic Left Heart Syndrome

Advancements in prenatal diagnosis and management of hypoplastic left heart syndrome: A multidisciplinary approach and future directions

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.

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.

Evaluation of right ventricular myocardial deformation properties in fetal hypoplastic left heart by two-dimensional speckle tracking echocardiography

PURPOSE

Right ventricular (RV) function influences the outcome of hypoplastic left heart (HLH) patients. This study aimed to confirm the assumption of prenatal RV remodeling and possible influencing factors of myocardial restructuring using two-dimensional speckle tracking echocardiography (2D STE).

METHODS

This is a retrospective cross-sectional cohort study including HLH fetuses and gestational age-matched controls. Based on a four-chamber view, cine loops were stored with 60 frames per second. Global longitudinal peak systolic strain (GLPSS) of the RV was retrospectively determined and compared to healthy controls. Furthermore, HLH subgroups were built according to the presence of left ventricular endocardial fibroelastosis (LV-EFE) and restrictive foramen ovale (FO) to investigate the effect of these compromising factors on myocardial deformation.

RESULTS

A total of 41 HLH fetuses and 101 controls were included. Gestational age at fetal assessment was similarly distributed in both groups (controls: 26.0 ± 5.6 weeks vs. HLH: 29.1 ± 5.6 weeks). Relating to RV-GLPSS values, fetuses with HLH demonstrated lower mean values than healthy control fetuses (- 15.65% vs. - 16.80%, p = 0.065). Cases with LV-EFE (n = 11) showed significantly lower mean values compared to such without LV-EFE (n = 30) (RV-GLPSS: - 12.12% vs. - 16.52%, p = 0.003). No significant differences were observed for cases with FO restriction (n = 10).

CONCLUSIONS

In HLH the RV undergoes prenatal remodeling, leading to an adaptation of myocardial function to LV conditions. Further explorations by STE should expand knowledge about RV contraction properties in HLH and its impact on surgical outcome.

Fetal Hemodynamic Response to Maternal Oxygenation in Normal and Complicated Pregnancies

Maternal oxygenation (MO) is widely applied in obstetrics. Scholars have conducted numerous studies on maternal hyperoxygenation and have reported many theoretical and applied achievements and a number of different points of view. The main purpose of this article is to discuss the effect of maternal oxygenation on fetal circulation during normal and complicated pregnancies and to ascertain its potential side effects and research gaps in this field. In complicated pregnancies, the fetus may benefit from oxygen therapy. However, large randomized controlled trials and longitudinal studies are necessary to support the widespread application of maternal oxygenation in this context.

A "holistic" sonographic view on congenital heart disease: How automatic reconstruction using fetal intelligent navigation echocardiography eases unveiling of abnormal cardiac anatomy part II-Left heart anomalies

Volume ultrasound has been shown to provide valid complementary information on fetal anatomy. Four-dimensional assessment (4D) of the fetal cardiovascular system using spatial-temporal image correlation (STIC) allows for detailed examination of a highly complex organ from the early second trimester onward. There is compelling evidence that this technique harbors quite a number of diagnostic opportunities, but manual navigation through STIC volume datasets is highly operator dependent. In fact, STIC is not incorporated yet into daily practice. Application of the novel fetal intelligent navigation echocardiography (FINE) considerably simplifies fetal cardiac volumetric examinations. This automatic technique applied on cardiac volume datasets reportedly has both high sensitivity and specificity for the detection of congenital heart defects (CHDs). Part I reviewed current data regarding detection rates of CHDs and illustrated the additional value of an automatic approach in delineating cardiac anatomy exemplified by congenital lesions of the right heart. In part II of this pictorial essay, we focused on left heart anomalies and aimed to tabulate recent findings on the quantification of normal and abnormal cardiac anatomy.

First-Trimester Diagnosis of Hypoplastic Left Heart Syndrome: A Case Report

Hypoplastic left heart syndrome (HLHS) comprises a spectrum of left-sided heart anomalies resulting from left outflow or inflow obstruction. Obstruction most often occurs at the levels of the aortic valve and/or mitral valve due to stenosis or atresia. HLHS is a lethal cardiac anomaly if not treated within the first week of life. Knowledge of sonographic features could aid in early detection, which results in better planning and management of pregnancy. This report presents a case in which HLHS was discovered during a routine dating and viability sonogram, performed at 12 weeks’ gestation.

Current perspective and scope of fetal therapy: part 1

Fetal therapy term has been described for any therapeutic intervention either invasive or noninvasive for the purpose of correcting or treating any fetal malformation or condition. Fetal therapy is a rapidly evolving specialty and has gained pace in last two decades and now fetal intervention is being tried in many malformations with rate of success varying with the type of different fetal conditions. The advances in imaging techniques have allowed fetal medicine persons to make earlier and accurate diagnosis of numerous fetal anomalies. Still many fetal anomalies are managed postnatally because the fetal outcomes have not changed significantly with the use of fetal therapy and this approach avoids unnecessary maternal risk secondary to inutero intervention. The short-term maternal risk associated with fetal surgery includes preterm labor, premature rupture of membranes, uterine wall bleeding, chorioamniotic separation, placental abruption, chorioamnionitis, and anesthesia risk. Whereas, maternal long-term complications include risk of infertility, uterine rupture, and need for cesarean section in future pregnancies. The decision for invasive fetal therapy should be taken after discussion with parents about the various aspects like postnatal fetal outcome without fetal intervention, possible outcome if the fetal intervention is done, available postnatal intervention for the fetal condition, and possible short-term and long-term maternal complications. The center where fetal intervention is done should have facility of multi-disciplinary team to manage both maternal and fetal complications. The major issues in the development of fetal surgery include selection of patient for intervention, crafting effective fetal surgical skills, requirement of regular fetal and uterine monitoring, effective tocolysis, and minimizing fetal and maternal fetal risks. This review will cover the surgical or invasive aspect of fetal therapy with available evidence and will highlight the progress made in the management of fetal malformations in last two decades.

Fetal Transcatheter Trileaflet Heart Valve Hemodynamics: Implications of Scaling on Valve Mechanics and Turbulence

The scarcity of data available on the best approach for pulmonary fetal valve replacement or implantation necessitate an investigation on whether practices using adult transcatheter valves could be translated to fetal applications. The objective of this study is to evaluate the hemodynamic characteristics and the turbulent properties of a fetal sized trileaflet transcatheter pulmonary valve in comparison with an adult balloon-expandable valve in order to assess the possibility of designing valves for fetal applications using dynamic similarity. A 6 mm fetal trileaflet valve and a 26 mm SAPIEN 3 valve were assessed in a pulse duplicator. Particle image velocimetry was performed. Pressure gradient (ΔP), effective orifice area (EOA), regurgitant fractions (RF), pinwheeling indices (PI) and turbulent stresses were evaluated. ΔP was 8.56 ± 0.139 and 7.76 ± 0.083 mmHg with fetal valve and SAPIEN respectively (p < 0.0001); EOA was 0.10 ± 0.0007 and 2.1 ± 0.025 cm2 with fetal valve and SAPIEN respectively (p < 0.0001); RF with the fetal valve was 2.35 ± 1.99% and with SAPIEN 10.92 ± 0.11% (p < 0.0001); PI with fetal valve was 0.404 ± 0.01 and with SAPIEN 0.37 ± 0.07; The flow regime with the fetal valve was turbulent and Reynolds numbers reached about 7000 while those with the SAPIEN reached about 20,000 at peak velocity. Turbulent stresses were significantly higher with fetal valve compared with SAPIEN. Instantaneous viscous shear stresses with fetal valve were 5.8 times higher than those obtained with SAPIEN and Reynolds shear stresses were 2.5 times higher during peak systole. The fetal valve implantation leads to a turbulent flow (specific to this particular type and design of valve) regime unlike what is expected of a small valve with different flow properties compared to adult valves.

Ventricular Dysfunction in the Case of the Sever Fetal Aortic Stenosis – the Role of Speckle-tracking

Congenital aortic stenosis (AS) occurs in around 0.2–0.5% of newborns, and its clinical severity is quite variable. Some of the newborns with AS require urgent medical care: prostaglandin infusion, balloon aortic valvuloplasty, or surgical intervention. Despite having a severe clinical evolution in neonates, the prenatal diagnosis of congenital AS is quite low. We present the case of a fetus with critical AS, who had been prenatally diagnosed at 35 weeks of gestation, via fetal cardiac ultra-sound. The echocardiographic parameters revealed a severely depressed left ventricular systolic function, with dilated chambers, and a severe aortic stenosis. Offline speckle-tracking analysis was performed in order to aid in deciding the optimal methods and timing of delivery. Left ventricular analysis revealed a severely impaired global longitudinal strain of 2.1%, left ventricular ejection fraction 18.4%, increased LV volumes, while the right ventricular function was only mildly depressed. Therefore, the decision was to delay the premature delivery, and the fetus was born at a gestational age of 38 weeks, in a hospital with a neonatal cardiovascular surgery department. The patient had undergone surgical repair of the cardiac anomaly at 3 days after birth.