World experience of percutaneous ultrasound-guided balloon valvuloplasty in human fetuses with severe aortic valve obstruction

Ethical Considerations in Fetal Cardiology

Fetal cardiology has evolved over the last 40 years and changed the timing of diagnosis and counseling of congenital heart disease, decision-making, planning for treatment at birth, and predicting future surgery from the postnatal to the prenatal period. Ethical issues in fetal cardiology transect multiple aspects of biomedical ethics including improvement in prenatal detection and diagnostic capabilities, access to equitable comprehensive care that preserves a pregnant person's right to make decisions, access to all reproductive options, informed consent, complexity in shared decision-making, and appropriate use of fetal cardiac interventions. This paper first reviews the literature and then provides an ethical analysis of accurate and timely diagnosis, equitable delivery of care, prenatal counseling and shared decision-making, and innovation through in utero intervention.

Catheter-Based Fetal Cardiac Interventions

Fetal cardiac intervention (FCI) is an emerging and rapidly advancing group of interventions designed to improve outcomes for fetuses with cardiovascular disease. Currently, FCI is comprised of pharmacologic therapies (e.g., trans-placental antiarrhythmics for fetal arrhythmia), open surgical procedures (e.g., surgical resection of pericardial teratoma), and catheter-based procedures (e.g., fetal aortic valvuloplasty for aortic stenosis). This review focuses on the rationale, criteria for inclusion, technical details, and current outcomes of the three most frequently performed catheter-based FCI procedures: (1) aortic valvuloplasty for critical aortic stenosis (AS) associated with evolving hypoplastic left heart syndrome (HLHS), (2) atrial septal intervention for HLHS with severely restrictive or intact atrial septum (R/IAS), and (3) pulmonary valvuloplasty for pulmonary atresia with intact ventricular septum (PA/IVS).

Technical Success and Serious Adverse Events for Fetal Aortic Valvuloplasty in a Large 20-Year Cohort

Background

FAV is offered to fetuses with severe aortic valve stenosis and evolving hypoplastic left heart syndrome. An inferential analysis of TS and SAE in a large series has not been reported.

Objectives

The purpose of this study was to determine factors associated with fetal aortic valvuloplasty (FAV) technical success (TS) and serious adverse events (SAEs).

Methods

Retrospective, single-center, cohort analysis of attempted FAV from March 1, 2000, to December 31, 2020. The primary outcome was the TS of FAV, and the secondary outcome was the presence of an SAE.

Results

A total of 165 FAVs were attempted in 163 patients with a median gestational age of 24.6 weeks (IQR: 22.9-27.1 weeks). FAV TS was 85% (141/165) and was higher in the 2010 to 2020 era (94% [85/90] vs 75% [56/75]; P < 0.001). Pre-FAV echocardiographic left ventricle (LV) long axis dimension z-score >-0.10 (P < 0.001) and higher LV ejection fraction (P = 0.037) were independently associated with a higher odds of TS. There were 117 SAEs in 67 attempted FAVs (41%), 13 of which were fetal deaths (7.9%). By classification and regression tree analysis, gestational age <21 weeks or in older fetuses, a procedure time of ≥39.6 minutes was associated with higher SAE rate. In the multivariable logistic regression model correcting for gestational age, fetuses with an LV end-diastolic volume <4.09 mL had an age-adjusted OR of 4.71 (95% CI: 1.67-13.29; P = 0.004) for experiencing an SAE.

Conclusions

TS of FAV has improved over time, and failure is associated with smaller fetal left heart sizes. SAEs are common and are associated with smaller left hearts and longer procedure times.

Minimally Invasive Bimanual Fetal Surgery—A Review

Background: The aim of this review is to discuss experimental and clinical techniques and interventions of fetal surgery which have been performed minimally invasively by the means of a three-port approach for the fetoscope and instruments for the left and right hand of the surgeon (bimanual minimally invasive fetal surgery). Methods: a print and electronic literature search was performed; the titles and abstracts were screened and included reports were reviewed in a two-step approach. First, reports other than minimally invasive fetal surgery were excluded, then a full text review and analysis of the reported data was performed. Results: 17 reports were included. The heterogeneity of the included reports was high. Although reports on human fetoscopic surgical procedures can be found, most of them do not pick out bimanual fetal surgery as a central theme but rather address interventions applying a fetoscope with a working channel for a laser fiber, needle or flexible instrument. Most reports were on experimentation in animal models, the human application of minimally invasive fetoscopic bimanual surgery is rare and has at best been explored for the prenatal treatment of spina bifida. Some reported bimanual fetoscopic procedures were performed on the exteriorized uterus via a maternal laparotomy and can therefore not be classified as being truly minimally invasive. Discussion: our results demonstrate that minimally invasive fetoscopic bimanual surgery is rare, even in animal models, excluding many other techniques and procedures that are loosely termed ‘minimally invasive fetal surgery’ which we suggest to better label as ‘interventions’. Thus, more research on percutaneous minimally invasive bimanual fetoscopic surgery is warranted, with the aim to reduce the maternal, uterine and fetal trauma for correction of congenital malformations.

Prenatal and Postnatal Therapies for Down's Syndrome and Associated Developmental Anomalies and Degenerative Deficits: A Systematic Review of Guidelines and Trials

Down's syndrome (DS) is the most common genetic disorder at birth. Multiple developmental abnormalities before birth and early onset of degenerative deficits after birth are features of DS. Early treatment for the manifestations associated with DS in either prenatal or postnatal period may improve clinical outcomes. However, information available from professional bodies and to communities is very limited. We carried out a systematic review and attempted meta-analysis of clinical trials for developmental abnormalities and degenerative deficits in DS. Only 15 randomized controlled trials (RCTs) in 995 (24 days to 65 years old) individuals with DS showed some improvement in cognitive disorders, development and growth, and musculoskeletal problem. However, each trial used different parameters and methods to measure various outcomes. RCTs of prenatal interventions in fetus with DS are lacking. The efficacy and safety of specific interventions in DS are still largely unknown. Proper counseling of the potential treatment for pregnant mothers who wish to continue their pregnancy carrying fetus with DS, and to health care professionals who take care of them are not adequate nowadays.

New challenges of fetal therapy in Japan

Aim

To review new challenges of fetal therapy in Japan after the establishment of four existing fetal therapies as standard prenatal care with National Health Insurance coverage over the past 20 years.

Methods

Reported studies and our current research activities related to four fetal therapies newly performed in Japan were reviewed.

Results

Fetoscopic endoluminal tracheal occlusion (FETO) for congenital diaphragmatic hernia (CDH) aims to occlude the trachea using a detachable balloon to promote lung growth. Following the recent successful completion of an international randomized controlled trial for CDH, in which we participated, FETO is offered for severe left CDH to perform balloon insertion at 27–29 weeks and removal at 34 weeks of gestation. Fetal cystoscopy (FC) for low urinary tract obstruction was introduced to overcome the demerits of vesicoamniotic shunting. FC may provide a proper diagnosis by visual observation of the urethra and physiological treatment of the posterior urethral valve. The effectiveness of open fetal surgery for myelomeningocele (MMC), direct surgery with laparotomy and hysterotomy, for ameliorating hindbrain herniation and the motor function was demonstrated, but it was also associated with substantial maternal and fetal risks. Fetal aortic valvuloplasty (FAV), ultrasound‐guided fetal aortic balloon dilation for critical aortic stenosis with evolving hypoplastic left heart syndrome may improve left heart development and maintain biventricular circulation. Feasibility and safety studies for FC, MMC open fetal surgery, and FAV are currently ongoing.

Conclusions

Clinical research on FETO, FC, MMC open fetal surgery, and FAV has proceeded with careful preparations in Japan.

Intrauterine Valvuloplasty in Severe Aortic Stenosis-A Ten Years Single Center Experience

Objective: To assess the course and outcome of fetal aortic valvuloplasty (FAV) in fetuses with severe aortic stenosis (SAS) in a single center. Methods: All fetuses with a prenatal diagnosis of SAS with subsequent FAV were retrospectively collected in one tertiary center for fetal medicine over a period of 10 years. In the study, period fetuses with SAS were considered suitable for FAV in the presence of markedly elevated left ventricular pressures (maximum velocity of mitral regurgitation (MR Vmax) >250 cm/s and/or maximum velocity of aortic stenosis (AS Vmax) >250 cm/s), retrograde flow in the transverse aortic arch and a left ventricular length Z-score >−1. Results: In the study period 29 fetuses with AS were treated with 38 FAV. If reinterventions are included 82.7% of fetuses received a technically successful FAV. Procedure related death occurred in three (10.3%) cases, spontaneous fetal death in 2 (6.9%), and termination of pregnancy was performed in 3 cases (10.3%). Among the 21 live births (72.4%), four died in infancy. Among the remaining survivors, 8/17 (47.1%) had a biventricular outcome at the age of one year, 8/17 (47.1%) were univentricular and one infant (5.9%) is biventricular at the age of eight months. Fetuses with biventricular outcome had significantly greater left ventricular (LV) length Z-scores (p = 0.031), and lower tricuspid to mitral valve (TV/MV) ratios (p = 0.003). Conclusions: FAV has a high technical success rate and a low rate of procedure related mortality if performed in experienced hands. The success rate of biventricular circulation at the age of one year is moderate and seems to depend rather on the center’s experience and postnatal surgical strategies than solely on prenatal selection criteria. In the absence of randomized controlled trials, FAV remains an experimental intervention.

Postnatal circulation in patients with aortic stenosis undergoing fetal aortic valvuloplasty: systematic review and meta-analysis

OBJECTIVES

Fetal aortic valvuloplasty (FAV) has become a treatment option for critical fetal aortic stenosis (AS) with the goal of preserving biventricular circulation (BVC); however, to date, it is unclear how many patients undergoing FAV achieve BVC. The aim of this systematic review and meta-analysis was to investigate the type of postnatal circulation achieved following FAV.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. MEDLINE, EMBASE, Web of Science and the Cochrane Library were searched systematically for studies investigating postnatal circulation in patients with AS following FAV. Eligible for inclusion were original papers in the English language, published from 2000 to 2020, with at least 12 months of follow-up after birth. Review papers, abstracts, expert opinions, books, editorials and case reports were excluded. The titles and abstracts of all retrieved literature were screened, duplicates were excluded and the full texts of potentially eligible articles were obtained and assessed. The primary endpoint was type of postnatal circulation. Additional assessed outcomes included fetal death, live birth, neonatal death (NND), termination of pregnancy (TOP) and technical success of the FAV procedure. The quality of articles was assessed using the Critical Appraisal Skills Programme (CASP) tool. To estimate the overall proportion of each endpoint, meta-analysis of proportions was employed using a random-effects model.

RESULTS

The electronic search identified 579 studies, of which seven were considered eligible for inclusion in the systematic review and meta-analysis. A total of 266 fetuses underwent FAV with median follow-up per study from 12 months to 13.2 years. There were no maternal deaths and only one case of FAV-related maternal complication was reported. Hydrops was present in 29 (11%) patients. The pooled prevalence of BVC and univentricular circulation (UVC) among liveborn patients was 45.8% (95% CI, 39.2-52.4%) and 43.6% (95% CI, 33.9-53.8%), respectively. The pooled prevalence of technically successful FAV procedure was 82.1% (95% CI, 74.3-87.9%), of fetal death it was 16.0% (95% CI, 11.2-22.4%), of TOP 5.7% (95% CI, 2.0-15.5%), of live birth 78.8% (95% CI, 66.5-87.4%), of NND 8.7% (95% CI, 4.7-15.5%), of palliative care 4.0% (95% CI, 1.9-8.4%) and of infant death 10.3% (95% CI, 3.6-26.1%). The pooled prevalence of BVC and UVC among liveborn patients who had technically successful FAV was 51.9% (95% CI, 44.7-59.1%) and 39.8% (95% CI, 29.7-50.9%), respectively.

CONCLUSIONS

This study showed a BVC rate of 46% among liveborn patients with AS undergoing FAV, which improved to 52% when subjects underwent technically successful FAV. Given the lack of randomized clinical trials, results should be interpreted with caution. Currently, data do not suggest a true benefit of FAV for achieving BVC. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Hypoplastic Left Heart Syndrome: Is There a Role for Fetal Therapy?

During fetal life some cardiac defects may lead to diminished left heart growth and to the evolution of a form of hypoplastic left heart syndrome (HLHS). In fetuses with an established HLHS, severe restriction or premature closure of the atrial septum leads to left atrial hypertension and remodeling of the pulmonary vasculature, severely worsening an already poor prognosis. Fetal therapy, including invasive fetal cardiac interventions and non-invasive maternal hyperoxygenation, have been introduced to prevent a possible progression of left heart hypoplasia, improve postnatal outcome, or secure fetal survival. The aim of this review is to cover patient selection and possible hemodynamic effects of fetal cardiac procedures and maternal hyperoxygenation in fetuses with an evolving or established hypoplastic left heart syndrome.

Foetoscopy-assisted balloon valvuloplasty in a human foetus with disadvantageous intrauterine position: a case report

Background

Some foetuses scheduled for balloon valvuloplasty present with unfavourable lies that render a successful procedure unlikely or impossible. In these situations, foetal posturing previously has been achieved by maternal laparotomy. As a less invasive means, we demonstrate the feasibility of a minimally invasive foetoscopic approach.

Case summary

Percutaneous ultrasound-guided foetal balloon valvuloplasty for severe aortic valve stenosis was attempted in a human foetus at 29 + 4 weeks of gestation under general maternofoetal anaesthesia. Unfortunately, prior to the procedure, the foetus had been observed on several occasions remaining in a dorsoanterior cephalic position. Therefore, the left ventricle could not be accessed by the conventional percutaneous ultrasound-guided approach. In order to achieve the desired foetal lie, foetoscopic assistance was employed: using a standardized foetoscopic setup, a foetoscope and two graspers, the foetus was rotated in dorsoposterior position. After this manoeuver, successful balloon valvuloplasty was achieved. Mother and foetus tolerated the procedure well and complications were not observed.

Discussion

Foetoscopy-assisted foetal posturing offers itself as an alternative to maternal laparotomy in foetuses presenting with a persisting disadvantageous position at the time of balloon valvuloplasty. Due to the increased risks of preterm rupture of membranes and earlier delivery posed by the foetoscopic approach, this technique may preferably be used in more mature foetuses when foetal posturing cannot be achieved by other means.

Late gestation predictors of a postnatal biventricular circulation after fetal aortic valvuloplasty

OBJECTIVES

Fetal aortic valvuloplasty (FAV) for severe aortic stenosis (AS) has shown promise in averting progression to hypoplastic left heart syndrome. After FAV, predicting which fetuses will achieve a biventricular (BiV) circulation after birth remains challenging. Identifying predictors of postnatal circulation on late gestation echocardiography will improve parental counseling.

METHODS

Liveborn patients who underwent FAV and had late gestation echocardiography available were included (2000-2017, n = 96). Multivariable logistic regression and classification and regression tree analysis were utilized to identify independent predictors of BiV circulation.

RESULTS

Among 96 fetuses, 50 (52.1%) had BiV circulation at the time of neonatal discharge. In multivariable analysis, independent predictors of biventricular circulation included left ventricular (LV) long axis z-score (OR 3.2, 95% CI 1.8-5.7, p < 0.001), LV ejection fraction (OR 1.3, 95% CI 1.0-1.8, p = 0.023), anterograde aortic arch flow (OR 5.0, 95% CI 1.2-20.4, p = 0.024), and bidirectional or right-to-left foramen ovale flow (OR 4.6, 95% CI 1.4-15.8, p = 0.015).

CONCLUSION

Several anatomic and physiologic parameters in late gestation were found to be independent predictors of BiV circulation after FAV. Identifying these predictors adds to our understanding of LV growth and hemodynamics after FAV and may improve parental counseling.

Fetal aortic valvuloplasty: first report of two cases from Saudi Arabia

Background

Fetal aortic stenosis may progress to hypoplastic left heart syndrome (HLHS), which carries a poor prognosis. We report two infants with fetal aortic stenosis successfully treated with fetal aortic valvuloplasty (FAV) using balloon dilatation.

Case presentation

Of five fetuses with aortic stenosis fulfilling the FAV criteria of severe aortic stenosis with a left ventricular length Z-score of ≥ − 2, retrograde flow in the transverse aortic arch, left-to-right flow across the foramen ovale, monophasic mitral inflow, and significant left ventricular dysfunction, we obtained permission for FAV in two fetuses. FAV was performed successfully under echocardiographic guidance using balloon dilatation. Both fetuses survived to birth. During FAV, mild pericardial effusion developed when introducing the stylet needle in the second fetus, and this resolved within 48 h. No intraprocedural complications occurred in the first patient, and no maternal complications occurred. The first infant underwent the Ross procedure after birth and is currently 7 years old and doing well. The second patient underwent aortic and mitral valve repair with endocardial fibroelastosis resection approximately 2 weeks after birth, which temporarily addressed the mitral valve stenosis; high doses of inotropes were subsequently required. The infant died of sepsis at 2 months of age.

Conclusion

FAV using balloon dilatation to treat fetal aortic stenosis was successful in our two patients, with subsequent neonatal biventricular repair resulting in long-term survival in one patient and death secondary to sepsis in the second patient.

Ultrasound-Guided Percutaneous Balloon Aortic Valvuloplasty for Aortic Stenosis

Percutaneous balloon aortic valvuloplasty (PBAV), which is used to treat symptomatic aortic stenosis, requires ionizing radiation and contrast agent for imaging guidance. The aim of the study is to evaluate the feasibility and effectiveness of ultrasound-guided PBAV in patients with aortic stenosis. This case series included 30 patients (14 males; mean age, 61.5 ± 4.5 years) with moderate/severe aortic stenosis treated with ultrasound-guided PBAV at the Ultrasound Department, Fuwai Hospital, Beijing, China, between January 2016 and July 2019. Cardiac function (New York Heart Association grade) was assessed before PBAV and 1 month after the procedure. Aortic peak jet velocity, aortic valve orifice area (AVA), mean transvalvular pressure gradient (MTPG), left ventricular end-diastolic diameter (LVDD), left ventricular ejection fraction (LVEF), and left ventricular end-systolic diameter (LVESD) were determined before and immediately after PBAV using Doppler echocardiography. Preprocedural cardiac function was grade I in 3 cases, grade II in 9 cases, grade III in 10 cases, and grade IV in 8 cases. Postprocedural cardiac function was grade I in 22 cases, grade II in 4 cases, and grade III in 4 cases, suggesting that cardiac function was improved by PBAV. Ultrasound-guided PBAV resulted in significant improvements (P < 0.05) in aortic peak jet velocity (3.68 ± 0.811 m/s vs. 4.79 ± 0.63 m/s), MTPG (33.77 ± 13.85 mmHg vs. 54.54 ± 13.81 mmHg), AVA (1.96 ± 0.25 cm² vs. 0.98 ± 0.12 cm²), LVEDD (51.90 ± 3.21 mm vs. 65.60 ± 6.81 mm), LVEF (63.46 ± 11.29% vs. 56.31 ± 11.04%), and LVESD (35.50 2.62 mm vs. 45.20 ± 2.42 mm). Ultrasound-guided PBAV is feasible and achieves good short-term effects in patients with aortic stenosis.

Fetal Aortic Valvuloplasty for Evolving Hypoplastic Left Heart Syndrome: A Decision Analysis

BACKGROUND

Fetal aortic valvuloplasty (FAV) may prevent progression of midgestation aortic stenosis to hypoplastic left heart syndrome. However, FAV has well-established risks, and its survival benefit remains unknown. Our primary aim was to determine whether FAV for midgestation aortic stenosis increases survival from fetal diagnosis to age 6 years.

METHODS AND RESULTS

We performed a retrospective analysis of 143 fetuses who underwent FAV from 2000 to 2017 and a secondary analysis of the Pediatric Heart Network Single Ventricle Reconstruction trial. Using these results, we developed a decision model to estimate probability of transplant-free survival from fetal diagnosis to age 6 years and postnatal restricted mean transplant-free survival time. FAV was technically successful in 84% of 143 fetuses with fetal demise in 8%. Biventricular circulation was achieved in 50% of 111 live-born infants with successful FAV but in only 16% of the 19 patients with unsuccessful FAV. The model projected overlapping probabilities of transplant-free survival to age 6 years at 75% (95% CI, 67%-82%) with FAV versus 72% (95% CI, 61%-82%) with expectant fetal management, resulting in a restricted mean transplant-free survival time benefit of 1.2 months. When limiting analyses to the improved FAV experience since 2009 to reflect current practice, (probability of technical success [94%], fetal demise [4%], and biventricular circulation [66%]), the model projected that FAV increased the probability of survival to age 6 years to 82% (95% CI, 73%-89%). Expectant management is favored if risk of fetal demise exceeded 12% or probability of biventricular circulation fell below 26%, but FAV remained favored over plausible recent range of technical success.

CONCLUSIONS

Our model suggests that FAV provides a modest, medium-term survival benefit over expectant fetal management. Appropriate patient selection and low risk of fetal demise with FAV are critical factors for obtaining a survival benefit.

Procedural, pregnancy, and short-term outcomes after fetal aortic valvuloplasty

OBJECTIVES

We aimed to evaluate the effect of technical aspects of fetal aortic valvuloplasty (FAV) on procedural risks and pregnancy outcomes.

BACKGROUND

FAV is performed in cases of severe mid-gestation aortic stenosis with the goal of preventing hypoplastic left heart syndrome (HLHS).

METHODS

The International Fetal Cardiac Intervention Registry was queried for fetuses who underwent FAV from 2002 to 2018, excluding one high-volume center.

RESULTS

The 108 fetuses had an attempted cardiac puncture (mean gestational age [GA] 26.1 ± 3.3 weeks). 83.3% of attempted interventions were technically successful (increased forward flow/new aortic insufficiency). The interventional cannula was larger than 19 g in 70.4%. More than one cardiac puncture was performed in 25.0%. Intraprocedural complications occurred in 48.1%, including bradycardia (34.1%), pericardial (22.2%) or pleural effusion (2.7%) requiring drainage, and balloon rupture (5.6%). Death within 48 hr occurred in 16.7% of fetuses. Of the 81 patients born alive, 59 were discharged home, 34 of whom had biventricular circulation. More than one cardiac puncture was associated with higher complication rates (p < .001). Larger cannula size was associated with higher pericardial effusion rates (p = .044). On multivariate analysis, technical success (odds ratio [OR] = 10.9, 95% confidence interval [CI] = 2.2-53.5, p = .003) and later GA at intervention (OR = 1.5, 95% CI = 1.2-1.9, p = .002) were associated with increased odds of live birth.

CONCLUSIONS

FAV is an often successful but high-risk procedure. Multiple cardiac punctures are associated with increased complication and fetal mortality rates. Later GA at intervention and technical success were independently associated with increased odds of live birth. However, performing the procedure later in gestation may miss the window to prevent progression to HLHS.

Fetal cardiac intervention-Perspectives from a single center

Fetal cardiac intervention was first proposed in the early 1990s to impact cardiac development and survival of fetuses with fetal aortic stenosis and evolving hypoplastic left heart syndrome (HLHS). Although initial attempts of fetal aortic valvuloplasty were unsuccessful and carried a high rate of morbidity and mortality, our collaborative group at the Brigham and Women's Hospital and Boston Children's Hospital have reinvigorated the procedure using improvements in imaging, anesthesia, balloon catheters, and surgical techniques. Two decades of experience have now allowed us to document the safety of in utero intervention and to achieve a better understanding of the impact of midgestation intervention on developing HLHS. Research into underlying genetics, predictive biomarkers, and ways to incorporate stem cell technology will hopefully allow us to further refine the procedure to most benefit children with this historically lethal disease.

Fetal aortic valvuloplasty to prevent progression to hypoplastic left heart syndrome in utero

Advances in fetal echocardiography have allowed for the prenatal diagnosis of congenital heart disease and an understanding of its natural history in utero. This insight has led to the development of fetal cardiac intervention (FCI) for select defects to prevent significant morbidity or mortality postnatally. Fetal aortic valvuloplasty (FAV) may be performed to prevent progression to hypoplastic left heart syndrome, a severe form of congenital heart disease, in utero. The current review focuses on this type of FCI and discusses the history of FAV, the rationale for intervention, candidate selection, procedural technique, and outcomes to date. Finally, the importance of building a multidisciplinary team to perform FCI is addressed.

Improved technical success, postnatal outcome and refined predictors of outcome for fetal aortic valvuloplasty

OBJECTIVES

Fetal aortic valvuloplasty (FAV) may prevent progression of mid-gestation aortic stenosis to hypoplastic left heart syndrome (HLHS). The aim of this study was to evaluate whether technical success and biventricular (Biv) outcome after FAV have changed from an earlier (2000-2008) to a more recent (2009-2015) era and identify pre-FAV predictors of Biv outcome.

METHODS

We evaluated procedural and postnatal outcomes in 123 fetuses that underwent FAV for evolving HLHS at Boston Children's Hospital between 2000 and 2015. The primary outcome measure was circulation type (Biv vs single ventricle) at the time of neonatal hospital discharge. Classification and regression tree (CART) analysis was performed to construct a stratification algorithm to predict Biv circulation based on pre-FAV fetal variables.

RESULTS

The FAV procedure was technically successful in 101/123 (82%) fetuses, with a higher technical success rate in the more recent era than in the earlier one (49/52 (94%) vs 52/71 (73%); P = 0.003). In liveborn patients, the incidence of Biv outcome was higher in the recent than in the earlier era, both in the entire liveborn cohort (29/49 (59%) vs 16/62 (26%); P = 0.001) and in those in whom the procedure was technically successful (27/46 (59%) vs 15/47 (32%); P = 0.007). Independent predictors of Biv outcome were higher left ventricular (LV) pressure, larger ascending aorta, better LV diastolic function and higher LV long-axis Z-score. On CART analysis, fetuses with LV pressure > 47 mmHg and ascending aorta Z-score ≥ 0.57 had a 92% probability of Biv outcome (n = 24). Those with a lower LV pressure, or mitral dimension Z-score < 0.1 and mitral valve inflow time Z-score < -2 (n = 34) were unlikely to have Biv (probability of 9%). The remainder of the patients had an intermediate (∼40-60%) likelihood of Biv circulation.

CONCLUSIONS

The proportion of patients achieving Biv outcome after FAV has increased, probably owing to an improved technical success rate and modified selection criteria. Fetal factors, including LV pressure, size of the ascending aorta and diastolic function, are associated with likelihood of Biv circulation after FAV. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Perinatal outcomes and intrauterine complications following fetal intervention for congenital heart disease: systematic review and meta-analysis of observational studies

OBJECTIVE

To assess perinatal outcomes and intrauterine complications following fetal intervention for congenital heart disease (CHD).

METHODS

A systematic review and meta-analysis were performed following an electronic search of PubMed and Scopus databases (last searched August 2015). Perinatal outcomes that were assessed included fetal death, live birth, preterm delivery < 37 weeks' gestation and neonatal death. Intrauterine complications that were assessed included bradycardia requiring treatment and hemopericardium requiring drainage. Estimated proportions were reported as mean (95% CI). Inconsistency was assessed using the I² statistic.

RESULTS

An electronic search identified 2279 records, of which 29 studies (11 retrospective cohort and 18 case reports) were considered eligible for analysis. Fetal death after treatment of CHD by aortic valvuloplasty was reported in three studies, with a rate of 31% (95% CI, 9-60%), after pulmonary valvuloplasty in one study, with a rate of 25% (95% CI, 10-49%), after septoplasty in one study, with a rate of 14% (95% CI, 6-28%) and after pericardiocentesis and/or pericardioamniotic shunt placement in 24 studies, with a rate of 29% (95% CI, 18-41%). Bradycardia requiring treatment was reported after aortic valvuloplasty in two studies, with a rate of 52% (95% CI, 16-87%), after pulmonary valvuloplasty in one study, with a rate of 44% (95% CI, 23-67%), and after septoplasty in one study, with a rate of 27% (95% CI, 15-43%).

CONCLUSIONS

Current evidence on the effectiveness of prenatal intervention for CHD derives mostly from case reports and a few larger series; no study was randomized. Although the results of the meta-analysis are encouraging in terms of perinatal survival, they should be interpreted with caution when comparing with procedures performed after delivery. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Fetal cardiac interventions: clinical and experimental research

Fetal cardiac interventions for congenital heart diseases may alleviate heart dysfunction, prevent them evolving into hypoplastic left heart syndrome, achieve biventricular outcome and improve fetal survival. Candidates for clinical fetal cardiac interventions are now restricted to cases of critical aortic valve stenosis with evolving hypoplastic left heart syndrome, pulmonary atresia with an intact ventricular septum and evolving hypoplastic right heart syndrome, and hypoplastic left heart syndrome with an intact or highly restrictive atrial septum as well as fetal heart block. The therapeutic options are advocated as prenatal aortic valvuloplasty, pulmonary valvuloplasty, creation of interatrial communication and fetal cardiac pacing. Experimental research on fetal cardiac intervention involves technical modifications of catheter-based cardiac clinical interventions and open fetal cardiac bypass that cannot be applied in human fetuses for the time being. Clinical fetal cardiac interventions are plausible for midgestation fetuses with the above-mentioned congenital heart defects. The technical success, biventricular outcome and fetal survival are continuously being improved in the conditions of the sophisticated multidisciplinary team, equipment, techniques and postnatal care. Experimental research is laying the foundations and may open new fields for catheter-based clinical techniques. In the present article, the clinical therapeutic options and experimental fetal cardiac interventions are described.

Low rate of prenatal diagnosis among neonates with critical aortic stenosis: insight into the natural history in utero

OBJECTIVES

To better understand the natural history and spectrum of fetal aortic stenosis (AS), we aimed to (1) determine the prenatal diagnosis rate of neonates with critical AS and a biventricular (BV) outcome, and (2) describe the findings at fetal echocardiography in patients diagnosed prenatally.

METHODS

A multicenter, retrospective study was performed on neonates who presented with critical AS and who were discharged with a BV outcome from 2000 to 2013. The prenatal diagnosis rate was compared with that reported for hypoplastic left heart syndrome (HLHS). We reviewed fetal echocardiographic findings in patients who were diagnosed prenatally.

RESULTS

In only 10 (8.5%) of 117 neonates with critical AS and a BV outcome was the diagnosis made prenatally, a rate significantly lower than that for HLHS in the contemporary era (82%; P < 0.0001). Of the 10 patients diagnosed prenatally, all had developed left ventricular dysfunction by a median gestational age of 33 (range, 28-35) weeks. When present, Doppler abnormalities such as retrograde flow in the aortic arch (n = 2), monophasic mitral inflow (n = 3) and left-to-right flow across the foramen ovale (n = 8) developed late in gestation (median 33 weeks).

CONCLUSION

The prenatal diagnosis rate of critical AS and a BV outcome among neonates is very low, probably owing to a relatively normal four-chamber view in mid-gestation with development of significant obstruction in the third trimester. The natural history contrasts with that of severe mid-gestation AS with evolving HLHS and suggests that the gestational timing of development of significant AS has an important impact on subsequent left-heart growth in utero.

Challenges and controversies in fetal diagnosis and treatment: hypoplastic left heart syndrome

Today, almost 70% of babies with hypoplastic left heart syndrome (HLHS) will survive into adulthood, although significant long-term morbidity and mortality still exists. Prenatal diagnosis of HLHS is increasingly common, allowing improved counseling, and the potential for fetal intervention if indicated. Exciting progress continues to be made in the area of fetal diagnosis and intervention, specifically catheter intervention for intact atrial septum or severe aortic stenosis. Pediatric cardiologists should be keenly aware of the flaws of staged palliation for the treatment of HLHS, and need to keep abreast of the emerging data regarding fetal diagnosis and intervention.

Diagnosis and treatment of fetal cardiac disease: a scientific statement from the American Heart Association

BACKGROUND

The goal of this statement is to review available literature and to put forth a scientific statement on the current practice of fetal cardiac medicine, including the diagnosis and management of fetal cardiovascular disease.

METHODS AND RESULTS

A writing group appointed by the American Heart Association reviewed the available literature pertaining to topics relevant to fetal cardiac medicine, including the diagnosis of congenital heart disease and arrhythmias, assessment of cardiac function and the cardiovascular system, and available treatment options. The American College of Cardiology/American Heart Association classification of recommendations and level of evidence for practice guidelines were applied to the current practice of fetal cardiac medicine. Recommendations relating to the specifics of fetal diagnosis, including the timing of referral for study, indications for referral, and experience suggested for performance and interpretation of studies, are presented. The components of a fetal echocardiogram are described in detail, including descriptions of the assessment of cardiac anatomy, cardiac function, and rhythm. Complementary modalities for fetal cardiac assessment are reviewed, including the use of advanced ultrasound techniques, fetal magnetic resonance imaging, and fetal magnetocardiography and electrocardiography for rhythm assessment. Models for parental counseling and a discussion of parental stress and depression assessments are reviewed. Available fetal therapies, including medical management for arrhythmias or heart failure and closed or open intervention for diseases affecting the cardiovascular system such as twin-twin transfusion syndrome, lung masses, and vascular tumors, are highlighted. Catheter-based intervention strategies to prevent the progression of disease in utero are also discussed. Recommendations for delivery planning strategies for fetuses with congenital heart disease including models based on classification of disease severity and delivery room treatment will be highlighted. Outcome assessment is reviewed to show the benefit of prenatal diagnosis and management as they affect outcome for babies with congenital heart disease.

CONCLUSIONS

Fetal cardiac medicine has evolved considerably over the past 2 decades, predominantly in response to advances in imaging technology and innovations in therapies. The diagnosis of cardiac disease in the fetus is mostly made with ultrasound; however, new technologies, including 3- and 4-dimensional echocardiography, magnetic resonance imaging, and fetal electrocardiography and magnetocardiography, are available. Medical and interventional treatments for select diseases and strategies for delivery room care enable stabilization of high-risk fetuses and contribute to improved outcomes. This statement highlights what is currently known and recommended on the basis of evidence and experience in the rapidly advancing and highly specialized field of fetal cardiac care.

Characterization of the vessel geometry, flow mechanics and wall shear stress in the great arteries of wildtype prenatal mouse

Introduction

Abnormal fluid mechanical environment in the pre-natal cardiovascular system is hypothesized to play a significant role in causing structural heart malformations. It is thus important to improve our understanding of the prenatal cardiovascular fluid mechanical environment at multiple developmental time-points and vascular morphologies. We present such a study on fetal great arteries on the wildtype mouse from embryonic day 14.5 (E14.5) to near-term (E18.5).

Methods

Ultrasound bio-microscopy (UBM) was used to measure blood velocity of the great arteries. Subsequently, specimens were cryo-embedded and sectioned using episcopic fluorescent image capture (EFIC) to obtain high-resolution 2D serial image stacks, which were used for 3D reconstructions and quantitative measurement of great artery and aortic arch dimensions. EFIC and UBM data were input into subject-specific computational fluid dynamics (CFD) for modeling hemodynamics.

Results

In normal mouse fetuses between E14.5–18.5, ultrasound imaging showed gradual but statistically significant increase in blood velocity in the aorta, pulmonary trunk (with the ductus arteriosus), and descending aorta. Measurement by EFIC imaging displayed a similar increase in cross sectional area of these vessels. However, CFD modeling showed great artery average wall shear stress and wall shear rate remain relatively constant with age and with vessel size, indicating that hemodynamic shear had a relative constancy over gestational period considered here.

Conclusion

Our EFIC-UBM-CFD method allowed reasonably detailed characterization of fetal mouse vascular geometry and fluid mechanics. Our results suggest that a homeostatic mechanism for restoring vascular wall shear magnitudes may exist during normal embryonic development. We speculate that this mechanism regulates the growth of the great vessels.

Neonatal aortic stenosis

Neonatal aortic stenosis is a complex and heterogeneous condition, defined as left ventricular outflow tract obstruction at valvular level, presenting and often requiring treatment in the first month of life. Initial presentation may be catastrophic, necessitating hemodynamic, respiratory and metabolic resuscitation. Subsequent management is focused on maintaining systemic blood flow, either via a univentricular Norwood palliation or a biventricular route, in which the effective aortic valve area is increased by balloon dilation or surgical valvotomy. In infants with aortic annular hypoplasia but adequately sized left ventricle, the Ross-Konno procedure is also an attractive option. Outcomes after biventricular management have improved in recent years as a consequence of better patient selection, perioperative management and advances in catheter technology. Exciting new developments are likely to significantly modify the natural history of this disorder, including fetal intervention for the salvage of the hypoplastic left ventricle; 3D echocardiography providing better definition of valve morphology and aiding patient selection for a surgical or catheter-based intervention; and new transcutaneous approaches, such as duel beam echo, to perforate the valve.

Foetal aortic valvuloplasty: experience of five cases

OBJECTIVES

Foetal aortic valvuloplasty has been proposed as a strategy to improve left heart growth and function in foetuses with severe aortic stenosis at risk of progression to hypoplastic left heart syndrome. We report our experience with this intervention.

METHODS AND RESULTS

Between 2005 and 2010, five foetuses with aortic stenosis and at risk of progression to hypoplastic left heart syndrome underwent ultrasound-guided percutaneous foetal aortic valvuloplasty. There were no associated maternal complications or foetal demise. In one case, the pregnancy was terminated a couple of weeks after the intervention, one foetus evolved to hypoplastic left heart syndrome, and three did not.

CONCLUSIONS

Foetal aortic valvuloplasty seems to be a safe and feasible procedure. It has been reported that it has the potential to prevent progression to hypoplastic left heart syndrome in selected foetuses with severe aortic stenosis. Further investigation regarding physiological and clinical aspects of this disease both prenatally and postnatally will probably allow to improve therapeutic strategies and clinical outcome.

Fetal cardiac interventions: rationale, risk and benefit

Fetal congenital heart disease may progress during pregnancy and may lead to irreversible myocardial or pulmonary damage. The rationale of fetal intracardiac interventions is to change fetal hemodynamics, prevent secondary damage and improve long-term outcome at an acceptable risk for mother and fetus. This review focuses on the current experience about patient selection, risks and benefits of this technique.

New technologies for surgery of the congenital cardiac defect

The surgical repair of complex congenital heart defects frequently requires additional tissue in various forms, such as patches, conduits, and valves. These devices often require replacement over a patient's lifetime because of degeneration, calcification, or lack of growth. The main new technologies in congenital cardiac surgery aim at, on the one hand, avoiding such reoperations and, on the other hand, improving long-term outcomes of devices used to repair or replace diseased structural malformations. These technologies are: 1) new patches: CorMatrix® patches made of decellularized porcine small intestinal submucosa extracellular matrix; 2) new devices: the Melody® valve (for percutaneous pulmonary valve implantation) and tissue-engineered valved conduits (either decellularized scaffolds or polymeric scaffolds); and 3) new emerging fields, such as antenatal corrective cardiac surgery or robotically assisted congenital cardiac surgical procedures. These new technologies for structural malformation surgery are still in their infancy but certainly present great promise for the future. But the translation of these emerging technologies to routine health care and public health policy will also largely depend on economic considerations, value judgments, and political factors.

Leftward displacement of septum primum in hypoplastic left heart syndrome

Embryologic development of atrial septum primum antedates formation of the atrioventricular and semilunar valves. Leftward displacement of the superior attachment of septum primum (LDSP) has only been described in hypoplastic left heart syndrome (HLHS). This study reports the frequency of LDSP in HLHS and correlates LDSP with other echocardiographic features of HLHS. Preoperative echocardiograms for 72 consecutive patients with classic HLHS from 1996 to 2002 at Children's Hospital of Wisconsin were reviewed. One patient was excluded for inadequate imaging. Data for the 71 patients included the following: size, location, and Doppler gradient across the atrial septal defect (ASD); location of attachment of septum primum; size and patency of the aortic valve (AoV) annulus; size and patency of the mitral valve (MV) annulus; ascending aorta diameter (AAD); and left-ventricular end diastolic dimension (LVEDD). Patients were categorized into three groups: aortic atresia/mitral atresia (AA/MA), aortic atresia/mitral stenosis (AA/MS), and aortic stenosis/mitral stenosis (AS/MS). LDSP was seen in 46 of 71 patients (64 %). By diagnostic group, 32 of 35 patients with AA/MA had LDSP (91 %) compared with 10 of 19 AA/MS patients (53 %) and 4 of 17 AS/MS patients (24 %), p < 0.05. AoV patency was seen in 4 of 46 (9 %) patients with LDSP compared with 13 of 25 (52 %) patients with normal atrial attachment, p < 0.005. Mean left heart dimensions in infants with LDSP compared with normal attachment were as follows: AoV annulus 2.24 versus 3.83 mm, AAD 2.34 versus 4.1 mm, MV annulus 3.21 versus 6.48 mm, and LVEDD 6.38 versus 13.83 mm. By two-way analysis of variance of diagnostic category versus atrial septal attachment with interaction, MV annulus and AAD were independently predicted smaller by LDSP versus normal atrial attachment, p < 0.05. Nonsignificant factors included AoV annulus, LVEDD, ASD size, and Doppler gradient. LDSP correlates with more severe maldevelopment of the left heart in patients with HLHS. Because formation of septum primum precedes development and growth of the intracardiac valves, we speculate that LDSP may be an initiating event in the development of HLHS. In addition, prenatal identification of LDSP may help direct planning of potential in utero therapies.

Fetal diagnosis and imaging in cardiology

BACKGROUND

Fetal echocardiography plays a critical role in the diagnosis and management of structural, functional and rhythm-related fetal cardiovascular disease.

OBJECTIVES/METHODS

This article reviews the history of fetal echocardiography and the prenatal diagnosis of fetal cardiovascular disease as well as the evolution of the field of fetal cardiology. The clinical application of fetal echocardiography, including indications for referral, timing of referral and considerations in the diagnosis and serial assessment of fetal cardiovascular disease, is presented.

CONCLUSIONS

Newer directions in the field of fetal cardiology, including first trimester diagnoses and fetal intervention, will continue to expand its role in the evaluation and treatment of affected pregnancies in the future; however, equally as important are efforts to continue to improve prenatal detection rates.

Future Directions of Fetal Interventions in Congenital Heart Disease

Fetal interventions for congenital heart disease have become important treatment modalities in the past 10 to 15 years. The basic hypothesis has been that a prenatal intervention may remodel cardiac morphology and function to such an extent that it may favorably alter the in utero natural history, resulting in improved prenatal and postnatal outcomes, including an increased likelihood of achieving biventricular circulation. This review discusses the current indications, techniques, and outcomes of fetal cardiac interventions and provides a glimpse into the future with regard to technical improvements and newer treatment modalities, such as maternal oxygenation and in utero pacemaker implantation.

Intrauterine surgery--choices and limitations

BACKGROUND

The past decade has seen much progress in intrauterine surgery. Randomized trials have documented the benefit of some procedures of this type for the unborn child.

METHOD

Selective literature review

RESULTS

Randomized trials have demonstrated the benefit of fetoscopic laser coagulation of placental anastomoses in twin-to-twin transfusion syndrome (TTTS) and of intrauterine surgery via hysterotomy for the repair of spina bifida. Other fetoscopic procedures have yielded promising initial results but are not yet supported by findings from randomized trials. Some intrauterine surgical procedures must still be considered experimental in view of the lack of randomized trials and the rarity of the conditions they are designed to treat. Fetoscopic laser coagulation for TTTS is by far the most common procedure in fetal surgery; TTTS arises in roughly 1 in 2500 pregnancies. The other procedures discussed in this article are performed much less often and for rarer indications. In general, intrauterine surgery is indicated only to treat conditions that would otherwise lead to intrauterine death or irreversible prenatal damage.

CONCLUSION

Intrauterine surgery is a rapidly developing field. Prenatal intervention by laser coagulation is indicated to treat severe TTTS, as its benefit has been shown in a randomized trial. Not enough evidence is yet available for the possible benefit of intrauterine surgery to treat myelomeningocele and congenital diaphragmatic hernia. Other indications are experimental. When an indication for intrauterine surgery exists, the parents should be informed and, depending on their wishes, referred to a center where it can be performed.

Protective effects of indomethacin and dexamethasone in a goat model with intrauterine balloon aortic valvuloplasty

BACKGROUND

Intrauterine balloon aortic valvuloplasty (IUBAV) has been used for critical aortic stenosis. However, it is necessary to determine the fetal impairments such as preterm birth after this approach and to find a way to prevent or reduce them.

METHODS

In the present study, we evaluated the therapeutic value of indomethacin (IDM) and dexamethasone (DXS) on reducing the preterm birth rate in experimental goats after IUBAV.

RESULTS

Our results indicated that the administration of IDM/DXS significantly reduced the rate of premature birth. IDM/DXS treatment led to preservation of myocardial ultrastructure with less damage, and amelioration of the fetal and placental circulation. Furthermore, we found that norepinephrine (NE) level was positively associated with the degree of myocardial damage. IDM/DXS administration led to a significant decrease of operation-induced increase of NE levels, which may be associated with the protective effects of IDM/DXS. Lastly, we found that the administration of IDM/DXS did not induce the risk of ductus arteriosus closure or slow down fetal growth.

CONCLUSIONS

Our results indicate that IDM/DXS promotes a better gestational outcome at least partially by reducing stress response during and after the operation of IUBAV in the goat model. IDM/DXS may be a useful application in human patients during IUBAV intervention.

Progression of outflow tract obstruction in the fetus

Fetal ventricular outflow tract obstruction (OTO) is congenital heart disease with significant potential for progression before birth as a consequence of the unique nature of the fetal circulation. The pattern of evolution depends upon the timing of development, severity of obstruction and the influence of the OTO on the fetal atrioventricular valve and myocardial function. Critical aortic (AS) or pulmonary (PS) valve stenosis, the two most common forms of fetal OTO, may be associated with progressive ventricular and great artery hypoplasia if presenting early in gestation or with normal ventricular and great artery growth if evolving later in gestation. In some affected fetuses, AS or PS may lead to the evolution of fetal heart failure. This article will review our current understanding of the natural history of fetal AS and PS, experience with fetal intervention and future directions of research.

Rationale for and current status of prenatal cardiac intervention

The idea of prenatal intervention in congenital heart defects was put forward over 20 years ago, arising from the observation that some forms of cardiac malformation progressed in severity as pregnancy advanced. The simultaneous development of minimally invasive catheter techniques in children, led to the concept of treating the foetal heart directly, in an attempt to prevent the changes which had been observed. Early efforts at prenatal valvuloplasty were largely set aside after poor results and the coincidental development of alternative, increasingly successful, postnatal surgical strategies. However, in the last 10 years or so, some centres have revived and extended the interventional techniques, with some success. The application of these techniques is limited to very few conditions, and suitable cases are relatively uncommon. Exploration of these procedures, therefore, should be limited to very few centres and the results should be closely scrutinised before this becomes an accepted management option.

Severe aortic or pulmonary valve stenosis in premature infants

Successful treatment of severe aortic (AS) or pulmonary valve (PS) stenosis by balloon valvuloplasty in term neonates is well-established. Sometimes, AS or PS diagnosed antenatally, progresses to severe left or right ventricular hypoplasia respectively. Successful fetal balloon valvuloplasty cannot be assumed to significantly change the natural history. In this review of premature infants, balloon valvuloplasty was used in extremely small babies. Five with severe AS (32 to 36 weeks, birth weight 1.4 to 1.9 kg) had percutaneous balloon aortic valvuloplasty during the first 10 days of life. Seven infants with severe/critical PS (28 to 36 weeks, birth weight 1.2 to 1.9 kg) had percutaneous balloon pulmonary valvuloplasty during the first 9 days of life. Two with pulmonary atresia (1.9 and 0.85 kg), underwent successful radiofrequency assisted balloon pulmonary valvuloplasty. There were no procedural deaths but one infant developed severe aortic insufficiency.

Hypoplastic left heart syndrome, cor triatriatum and partial anomalous pulmonary venous connection: Imaging of a very rare association

A newborn is presented with an association of hypoplastic left heart syndrome, cor triatriatum and partial anomalous pulmonary venous connection. The diagnosis was established with echocardiography and further confirmed with computed tomography. To our knowledge the images of such an association have never been reported before.

Successful immediate newborn ross-konno and mitral valve repair following fetal aortic valvuloplasty

Perinatal management of severe mitral regurgitation (MR) and aortic stenosis (AS) is difficult; mortality is high, and there are few reports of successful postnatal biventricular repairs. We report a patient with severe MR and AS, diagnosed prenatally, that underwent a fetal aortic valvuloplasty and a successful modified Ross-Konno procedure with concomitant mitral valve repair shortly after birth.

Prenatally engineered autologous amniotic fluid stem cell-based heart valves in the fetal circulation

Prenatal heart valve interventions aiming at the early and systematic correction of congenital cardiac malformations represent a promising treatment option in maternal-fetal care. However, definite fetal valve replacements require growing implants adaptive to fetal and postnatal development. The presented study investigates the fetal implantation of prenatally engineered living autologous cell-based heart valves. Autologous amniotic fluid cells (AFCs) were isolated from pregnant sheep between 122 and 128 days of gestation via transuterine sonographic sampling. Stented trileaflet heart valves were fabricated from biodegradable PGA-P4HB composite matrices (n = 9) and seeded with AFCs in vitro. Within the same intervention, tissue engineered heart valves (TEHVs) and unseeded controls were implanted orthotopically into the pulmonary position using an in-utero closed-heart hybrid approach. The transapical valve deployments were successful in all animals with acute survival of 77.8% of fetuses. TEHV in-vivo functionality was assessed using echocardiography as well as angiography. Fetuses were harvested up to 1 week after implantation representing a birth-relevant gestational age. TEHVs showed in vivo functionality with intact valvular integrity and absence of thrombus formation. The presented approach may serve as an experimental basis for future human prenatal cardiac interventions using fully biodegradable autologous cell-based living materials.

Hypoplastic left heart syndrome: current considerations and expectations

In the recent era, no congenital heart defect has undergone a more dramatic change in diagnostic approach, management, and outcomes than hypoplastic left heart syndrome (HLHS). During this time, survival to the age of 5 years (including Fontan) has ranged from 50% to 69%, but current expectations are that 70% of newborns born today with HLHS may reach adulthood. Although the 3-stage treatment approach to HLHS is now well founded, there is significant variation among centers. In this white paper, we present the current state of the art in our understanding and treatment of HLHS during the stages of care: 1) pre-Stage I: fetal and neonatal assessment and management; 2) Stage I: perioperative care, interstage monitoring, and management strategies; 3) Stage II: surgeries; 4) Stage III: Fontan surgery; and 5) long-term follow-up. Issues surrounding the genetics of HLHS, developmental outcomes, and quality of life are addressed in addition to the many other considerations for caring for this group of complex patients.

Fetal trans-apical stent delivery into the pulmonary artery: prospects for prenatal heart-valve implantation

OBJECTIVE

The purpose of this study was to assess the technical feasibility of a fetal trans-apical stent delivery into the pulmonary artery using a novel hybrid-intervention technique as a possible route for prenatal minimally invasive heart-valve-implantation approaches.

METHODS

Pregnant Pre-Alp sheep between 122 and 128 days' gestation (n = 3) underwent a midline laparotomy. The fetus was left in utero or partially externalized and its chest was opened via a left-sided minithoracotomy. The fetal heart was cannulated and a guide wire was introduced through the ductus arteriosus into the aorta. A 14-French delivery system was then mounted onto the guide wire and advanced to the landing zone in the pulmonary artery, where the stent was deployed. The position of the stent was confirmed using echocardiography, angiography as well as computed tomography.

RESULTS

The trans-apical implantation was successful in all animals. However, at necropsy in one animal, the stent was found to partly occlude one of the pulmonary valvular leaflets. Bleeding at the antero-apical incision occurred in all animals but could be managed without fetal demise. No fetal cardiopulmonary bypass was performed. In all animals, contrast angiography displayed normal perfusion of the pulmonary vasculature as well as the ductus arteriosus.

CONCLUSIONS

Our study demonstrates the principal technical feasibility of a prenatal stent delivery into the pulmonary artery using a novel trans-apical hybrid-intervention technique. This approach demonstrates the first step towards possible future minimally invasive prenatal heart-valve-implantation procedures.