Factors affecting technical success of fetal aortic valve dilation

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.

Hemodynamic and Anatomic Changes after Fetal Aortic Valvuloplasty are associated with Procedural Success and Postnatal Biventricular Circulation

BACKGROUND

There are minimal data characterizing the trajectory of left heart growth and hemodynamics following fetal aortic valvuloplasty (FAV).

METHODS

This retrospective study included patients who underwent FAV between 2000 and 2019 with echocardiograms performed pre-FAV, immediately post-FAV, and in late gestation.

RESULTS

Of 118 fetuses undergoing FAV, 106 (90%) underwent technically successful FAV, of which 55 (52%) had biventricular circulation. Technically successful FAV was associated with improved aortic valve growth (p<0.001), sustained antegrade aortic arch (AoA) flow (p=0.02), improved mitral valve inflow pattern (p=0.002), and favorable patent foramen ovale (PFO) flow pattern (p=0.004) from pre-FAV to late gestation. Compared to patients with univentricular outcome, patients with biventricular outcome had less decrement in size of the left ventricle (LV) (p<0.001) and aortic valve (p=0.005), as well more physiologic PFO flow (p<0.001) and antegrade AoA flow (p<0.001) from pre-FAV to late gestation. In multivariable analysis, echocardiographic predictors of biventricular outcome were less decline in LV end diastolic dimension (p<0.001), improved PFO flow (p=0.004), and sustained antegrade AoA flow (p=0.002) from pre-FAV to late gestation.

CONCLUSION

Stabilization of left heart growth and improved hemodynamics following successful FAV through late gestation are associated with postnatal biventricular circulation. This article is protected by copyright. All rights reserved.

Fetal Cardiac Interventions-Are They Safe for the Mothers?

The aim of fetal cardiac interventions (FCI), as other prenatal therapeutic procedures, is to bring benefit to the fetus. However, the safety of the mother is of utmost importance. The objective of our study was to evaluate the impact of FCI on maternal condition, course of pregnancy, and delivery. 113 mothers underwent intrauterine treatment of their fetuses with critical heart defects. 128 percutaneous ultrasound-guided FCI were performed and analyzed. The patients were divided into four groups according to the type of FCI: balloon aortic valvuloplasty (fBAV), balloon pulmonary valvuloplasty (fBPV), interatrial stent placement (IAS), and balloon atrioseptoplasty (BAS). Various factors: maternal parameters, perioperative data, and pregnancy complications, were analyzed. There was only one major complication—procedure-related placental abruption (without need for blood products transfusion). There were no cases of: procedure-related preterm prelabor rupture of membranes (pPROM), chorioamnionitis, wound infection, and anesthesia associated complications. Tocolysis was only necessary only in two cases, and it was effective in both. None of the patients required intensive care unit admission. The procedure was effective in treating polyhydramnios associated with fetal heart failure in six out of nine cases. Deliveries occurred at term in 89%, 54% were vaginal. The results showed that FCI had a negligible impact on a further course of pregnancy and delivery.

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 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.

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.

Prenatal therapy for fetal cardiac disorders

Fetal cardiac abnormalities are some of the commonest congenital disorders seen in prenatal life. They can be anatomical or functional and can develop de novo or as a consequence of either maternal or fetal disease. Untreated, morbidity and mortality rates are high for hypoplastic left heart disorders and for some fetal tachy and bradyarrhythmias. Optimum management strategies are often not clear because of the lack of knowledge about the precise natural history of some of these conditions. Prenatal therapy ranges from invasive fetal cardiac intervention to maternal administration of drugs for transplacental transfer to the fetus. This comprehensive review covers many fetal cardiac disorders and various prenatal therapeutic options that are available.

Early hemodynamic changes after fetal aortic stenosis valvuloplasty predict biventricular circulation at birth

OBJECTIVE

To describe the early hemodynamic changes after fetal aortic valvuloplasty (FAV) for evolving hypoplastic left heart syndrome due to mid-gestational aortic stenosis and to assess whether these early changes predict biventricular (BiV) circulation at neonatal discharge.

METHOD

We retrospectively reviewed all technically successful FAV cases resulting in live birth between 2000 and 2015 (n = 93, 45% BiV circulation at neonatal discharge). Paired testing methods were used to compare pre-intervention and post-intervention measures of left ventricular hemodynamics. Logistic regression was used to determine whether these changes were predictive of post-natal outcome.

RESULTS

Measures of left heart physiology were markedly abnormal pre-FAV and improved significantly post-FAV. No subjects had systolic antegrade transverse aortic arch flow pre-FAV and 65% of subjects had antegrade flow post-FAV. The number of subjects with abnormal left-to-right patent foramen ovale flow decreased, and the number with biphasic mitral valve inflow increased. The median left ventricular ejection fraction improved after intervention. Amongst the pre-post changes, gaining partially or exclusively antegrade systolic arch flow was the most significant independent predictor of BiV circulation (OR 9.80 and 19.83, respectively, both P < 0.001).

CONCLUSION

Technically successful FAV is associated with immediate improvements in left heart physiology that are predictive of BiV circulation at neonatal discharge.

A potentially curative fetal intervention for hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) encapsulates a spectrum of complex congenital cardiovascular malformations involving varying degrees of underdevelopment of the left-sided heart structures. However, despite improved survival rates since the introduction of staged surgical reconstruction, treatment options for HLHS remain palliative rather than curative. A major limiting factor in the development of definitive curative therapy for HLHS is an incomplete understanding of its pathogenesis. Currently, the aetiology HLHS is best conceptualised by the 'flow theory' of cardiogenesis, which states that normal cardiac development is reliant on the interrelationship of normal flow patterns of blood through the developing heart, and appropriate growth of the cardiac valves and myocardium. Thus, congenital cardiac malformations, such as HLHS, are thought to arise when these two processes are incorrectly coupled in utero. The rationale for the hypothesis proposed herein rests upon the flow theory of cardiogenesis. Morphological studies of HLHS indicate that, although underdeveloped, all left-sided cardiac structures are present and anatomically correct. Further, of the various structural abnormalities that can occur within the spectrum of HLHS, the presence of a ventricular septal defect (VSD) is rare. The rarity of a VSD within the morphological spectrum of HLHS suggests the syndrome may not develop in the presence of a functionally significant VSD. Presumably, the presence of a functional VSD establishes a communication between the two ventricles during cardiac development, and preserves the normal pressure-flow-dependent growth of the left ventricular (LV) myocardium, despite inflow/outflow valve defects. It is proposed that surgical creation of a VSD in utero will 'rescue' the LV of hearts with left-sided valvular deformities that render them susceptible to the development of HLHS later in gestation. In evaluating this hypothesis, potential techniques for surgical creation of a VSD in utero are offered. These techniques are based on already established catheter-based in utero interventions, and conventional postnatal percutaneous procedures for VSD creation. Further discussion is also offered on techniques to avoid, and manage, potential complications (i.e. conduction system damage) of the proposed technique(s). Finally, if VSD creation in utero is indeed practically feasible, and successfully establishes the hypothesised hemodynamic and myocardial growth normalisation within the abnormally developing LV, the clinical implications are profound. This procedure may hold a potential cure for almost every sub-type of HLHS.

Texture analysis of the developing human brain using customization of a knowledge-based system

Background: Pattern recognition software originally designed for geospatial and other technical applications could be trained by physicians and used as texture-analysis tools for evidence-based practice, in order to improve diagnostic imaging examination during pregnancy.Methods: Various machine-learning techniques and customized datasets were assessed for training of an integrable knowledge-based system (KBS), to determine a hypothetical methodology for texture classification of closely-related anatomical structures in fetal brain magnetic resonance (MR) images. Samples were manually categorized according to the magnetic field of the MRI scanner (i.e. 1.5-tesla (1.5T), 3-tesla (3T)), rotational planes (i.e. coronal, sagittal and axial), and signal weighting (i.e. spin-lattice, spin-spin, relaxation, proton density). In the machine-learning sessions, the operator manually selected relevant regions of interest (ROI) in 1.5/3T MR images. Semi-automatic procedures in MaZda/B11 were performed to determine optimal parameter sets for ROI classification. Four classes were defined: ventricles, thalamus, grey matter, and white matter. Various textures analysis methods were tested. The KBS performed automatic data pre-processing and semi-automatic classification of ROIs.Results: After testing 3456 ROIs, statistical binary classification revealed that combination of reduction techniques with linear discriminant algorithms (LDA) or nonlinear discriminant algorithms (NDA) yielded the best scoring in terms of sensitivity (both 100%, 95% CI: 99.79-100), specificity (both 100%, 95% CI: 99.79-100) and Fisher coefficient (≈E+4, ≈E+5, respectively). Conclusions: LDA and NDA in MaZda can be useful data mining tools for screening a population of interest subjected to a clinical test.

Fetal interventions for congenital heart disease

PURPOSE OF REVIEW

This article discusses the rationale, patient selection, technical aspects, and outcomes of percutaneous, ultrasound-guided fetal cardiac intervention (FCI) for structural congenital heart disease.

RECENT FINDINGS

FCI is most commonly performed for three forms of congenital heart disease: severe aortic stenosis with evolving hypoplastic left heart syndrome (HLHS), pulmonary atresia with intact ventricular septum and evolving hypoplastic right heart syndrome, and HLHS with intact or highly restrictive atrial septum. For severe aortic stenosis and pulmonary atresia with intact ventricular septum, the goal of intervention is to alter the natural history such that a biventricular circulation may be achieved postnatally. A growing number of patients have achieved a biventricular circulation; however, patient selection and postnatal management strategy are essential for success. HLHS with intact or highly restrictive atrial septum is one of the most lethal forms of congenital heart disease, and the goal of FCI is to improve survival. Although the creation of an atrial communication in utero is technically feasible and may permit greater stability in the immediate postnatal period, significant improvements in survival have not yet been reported.

SUMMARY

FCI is an evolving form of treatment for congenital heart disease that holds promise for select patients. Critical evaluation of both short and long-term outcomes is warranted.

Caregiver anxiety due to interstage feeding concerns

INTRODUCTION

Improved weight gain during the interstage (IS) period has been shown to improve overall outcomes in patients with single ventricle physiology (SVP). This emphasis on nutrition may have untoward effects, such as increasing anxiety/stress levels in caregivers, who are already known to be at risk for increased anxiety/stress levels. The goal of this study was to evaluate anxiety/stress levels of caregivers as it pertains to feeding during the IS period and to determine if certain characteristics were associated with higher anxiety/stress scores.

METHODS

Caregivers of children with SVP who completed the IS period, defined as the time between the first and second cardiac surgeries, were recruited. Baseline demographics were obtained. Anxiety/stress levels were measured via eight questions using a 0- to 10-point scale. Correlations were performed between demographic variables and anxiety/stress level scores.

RESULTS

Fifty-six surveys were completed (39 males, 27 females) on 43 children. Fourteen children required tube feeds during the IS period. There were significant correlations between anxiety/stress scores and caregiver's gender, caregiver's age, caregiver's level of education, percent of time a caregiver spent feeding the child, if caregivers were taking medications for anxiety, and if the child was seen in the emergency room during the IS period. There were no correlation of anxiety/stress scores with caregiver's race, child's underlying cardiac diagnosis, age of child, route of feeding during the IS period, birth order of the child or number of children in the family, relationship status, or distance from the hospital.

CONCLUSION

In general, caregivers of children with SVP experience anxiety/stress during the IS period specifically due to feeding concerns. Certain intrinsic and extrinsic characteristics were associated with higher anxiety/stress levels. Future studies are needed to determine how to minimize anxiety/stress levels during this stressful time period.

Maternal aspects of fetal cardiac intervention

OBJECTIVES

Fetal cardiac interventions have the potential to alter natural disease progression and reduce morbidity and mortality in children. Although there are already encouraging data on fetal outcome, information on maternal morbidity and mortality after intervention is scarce. The aim of the present study was to assess maternal aspects, pregnancy-associated risks and adverse events in 53 intrauterine cardiac interventions.

METHODS

Between October 2000 and December 2012, 53 fetal cardiac interventions were performed in 47 patients (43 aortic valve dilations in 39 patients, seven pulmonary valve dilations in six patients and three balloon atrioseptostomies in two patients). Median gestational age was 26 + 4 (range, 20 + 3 to 33 + 1) weeks. Interventions were performed by an ultrasound-guided percutaneous approach under general anesthesia. All medical records and patient charts were analyzed retrospectively.

RESULTS

All women were considered to be healthy in the preoperative assessment; 39 (83%) patients continued pregnancy until term and eight of 47 patients had an intrauterine fetal death (IUFD) and were induced. Postoperative nausea was reported in 29.8% of patients and abdominal pain in 36.2% of patients on the day of surgery. Preterm contractions were observed in two patients; no preterm prelabor rupture of membranes occurred. One severe postpartum hemorrhage was observed in a patient with IUFD and subsequent induction; however, this was unrelated to the balloon valvuloplasty. No intensive care unit admission and no major anesthesia-associated complications (aspiration, anaphylactic reaction, cardiovascular collapse, damage to teeth, laryngeal damage, awareness or hypoxic brain damage) were observed. Maternal mortality was zero. A significant learning curve was observed in terms of duration of intervention.

CONCLUSION

In our experience, percutaneous needle-guided fetal cardiac intervention seems to be a safe procedure for the mother. In 53 procedures no major maternal complication directly related to the intervention was observed.

Hypoplastic left heart syndrome - a review of supportive percutaneous treatment

Due to the complex anatomical and haemodynamic consequences of hypoplastic left heart syndrome (HLHS), patients with the condition require multistage surgical and supportive interventional treatment. Percutaneous interventions may be required between each stage of surgical palliation, sometimes simultaneously with surgery as hybrid interventions, or after completion of multistage treatment. Recent advances in the field of interventional cardiology, including new devices and techniques, have significantly contributed to improving results of multistage HLHS palliation. Knowledge of the potential interventional options as well as the limitation of percutaneous interventions will enable the creation of safe and effective treatment protocols in this highly challenging group of patients. In this comprehensive review we discuss the types, goals, and potential complications of transcatheter interventions in patients with HLHS.

Percutaneous fetal cardiac interventions for structural heart disease

INTRODUCTION

Prenatal diagnosis provides valuable information regarding a variety of congenital heart defects. Some defects occur early in gestation with little change throughout pregnancy, whereas others evolve during mid and late gestation. Fetal cardiac intervention (FCI) affords the opportunity to interrupt progression of disease in this latter category, resulting in improved perinatal and lifelong outcomes.

AIM

This chapter addresses three lesions for which percutaneous FCI can be utilized: (1) aortic stenosis with evolving hypoplastic left heart syndrome, for which aortic valvuloplasty may prevent left ventricular hypoplasia and has yielded a biventricular circulation in approximately one third of cases; (2) hypoplastic left heart syndrome with intact atrial septum, for which relief of atrial restriction has potential to improve perinatal survival; and (3) pulmonary atresia with intact ventricular septum and evolving right ventricular hypoplasia, for which pulmonary valvuloplasty has resulted in a biventricular circulation in the majority of patients. The pathophysiology, rationale for intervention, patient selection criteria, procedural technique, and outcomes for each lesion will be reviewed. This chapter will also review complications of FCI and their treatment, and maternal and fetal anesthesia specific to FCI. The importance of a specialized center with experience managing infants delivered after FCI will also be addressed.

Fetal aortic valvuloplasty for evolving hypoplastic left heart syndrome: postnatal outcomes of the first 100 patients

BACKGROUND

Fetal aortic valvuloplasty can be performed for severe midgestation aortic stenosis in an attempt to prevent progression to hypoplastic left heart syndrome (HLHS). A subset of patients has achieved a biventricular (BV) circulation after fetal aortic valvuloplasty. The postnatal outcomes and survival of the BV patients, in comparison with those managed as HLHS, have not been reported.

METHODS AND RESULTS

We included 100 patients who underwent fetal aortic valvuloplasty for severe midgestation aortic stenosis with evolving HLHS from March 2000 to January 2013. Patients were categorized based on postnatal management as BV or HLHS. Clinical records were reviewed. Eighty-eight fetuses were live-born, and 38 had a BV circulation (31 from birth, 7 converted after initial univentricular palliation). Left-sided structures, namely aortic and mitral valve sizes and left ventricular volume, were significantly larger in the BV group at the time of birth (P<0.01). After a median follow-up of 5.4 years, freedom from cardiac death among all BV patients was 96±4% at 5 years and 84±12% at 10 years, which was better than HLHS patients (log-rank P=0.04). There was no cardiac mortality in patients with a BV circulation from birth. All but 1 of the BV patients required postnatal intervention; 42% underwent aortic or mitral valve replacement. On the most recent echocardiogram, the median left ventricular end-diastolic volume z score was +1.7 (range, -1.3 to +8.2), and 80% had normal ejection fraction.

CONCLUSIONS

Short- and intermediate-term survival among patients who underwent fetal aortic valvuloplasty and achieved a BV circulation postnatally is encouraging. However, morbidity still exists, and ongoing assessment is warranted.

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.

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.

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.

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.

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.

Use of a pressure guidewire in fetal cardiac intervention for critical aortic stenosis

Fetal cardiac intervention for critical aortic stenosis (AS) with evolving hypoplastic left heart syndrome is performed in an attempt to maintain a biventricular circulation postnatally. The procedure has been hindered by technical challenges and poor candidate selection. We report here the novel use of a pressure guidewire during aortic valvuloplasty in a fetus at 21 weeks' gestation with critical AS and evolving hypoplastic left heart syndrome. Use of a pressure guidewire during fetal cardiac intervention offers several potential advantages over existing protocols. This technique augments fetal ultrasound as it relates to operator awareness of catheter and wire position (with continuous monitoring of pressure waveforms), improves on intraprocedural fetal hemodynamic monitoring and responsiveness to resuscitation, and provides a rich new data set of invasive fetal hemodynamics. This data set offers tremendous potential with regards to improving candidate selection and postintervention prognostication. In addition, we provide the first, to our knowledge, characterization of intracardiac pressures in a human fetus with congenital heart disease. Given the realized and potential benefits associated with this technique, use of a pressure guidewire may become standard of care for all fetal cardiac interventions.

Fetal surgery for cardiac lesions

Intrauterine dilation of critical fetal aortic stenosis (AS) and pulmonary stenosis or atresia has the potential to change the natural course of these congenital heart defects preventing progression to a single ventricle circulation. This article reviews the world experience in fetal cardiac interventions. In carefully selected cases, fetal cardiac surgery can reverse end-stage heart failure and can provide biventricular outcome postnatally in about two thirds of the cases with successful interventions.

Intrauterine aortic valvuloplasty in fetuses with critical aortic stenosis: experience and results of 24 procedures

OBJECTIVE

Valvuloplasty of the fetal aortic valve has the potential to prevent progression of critical aortic stenosis (AS) to hypoplastic left heart syndrome (HLHS). The aim of the study was to assess 24 aortic valvuloplasties regarding indications, success rate, procedure-related risks and outcome.

METHODS

Between January 2001 and December 2009 we performed 24 aortic valvuloplasties in 23 fetuses with critical AS at a median gestational age of 26 + 4 (range, 21 + 3 to 32 + 5) weeks by a transabdominal ultrasound-guided approach. Four fetuses had hydrops as a late sign of heart failure.

RESULTS

In 16/24 procedures (66.7%) corresponding to 16/23 fetuses (69.6%) the procedures were technically successful, with one intrauterine death in this group. After an initial learning curve, success rate improved to 78.6% (11 of the last 14 interventions were successful). In 10 out of the 15 (66.7%) successfully-treated and liveborn fetuses a biventricular circulation could be achieved postnatally. All four fetuses with hydrops had successful interventions, hydrops disappearing within 5 weeks. In 8/24 interventions (33.3%) the aortic valve could not be treated successfully, with intrauterine fetal death in two of these cases. In one fetus a repeat procedure was successful. All surviving fetuses with unsuccessful (n = 5) or no (n = 5) procedure performed developed HLHS until delivery.

CONCLUSIONS

Fetal aortic valvuloplasty could be performed successfully in selected fetuses with critical AS and evolving HLHS, with a biventricular outcome in two thirds of the patients. Safety and success rate were dependent on patient selection and the level of experience of the whole interventional team. In fetuses with AS and hydrops, aortic valvuloplasty could reverse end-stage heart failure and hydrops and ensure fetal survival.

New and/or improved aspects of fetal surgery

Open fetal surgery through a wide hysterotomy is no longer a real option for prenatal intervention, but a minimally invasive approach has emerged as treatment for a small number of indications. Endoscopic ablation of placental vessels is the preferred treatment for severe twin-to-twin transfusion syndrome and it may be the only chance to salvage the most severe forms of congenital diaphragmatic hernia. Several other indications are currently under review and may become justified in the future, provided that diagnostic accuracy and patient selection become more accurate. Before invasive fetal intervention becomes widely accepted, however, we need to better define outcome. It is no longer acceptable to express results in terms of survival at birth. Survival at discharge and long-term morbidity must be considered as well.

The learning curve for a fetal cardiac intervention team

Objectives. Multiple technical difficulties are encountered when a multidisciplinary team of subspecialists begins a minimally-invasive fetal cardiac interventional program. We describe the learning curve. Study Design. Ten pregnant sheep underwent ultrasound-guided balloon valvuloplasty of the aortic valve. Team members and their roles remained constant through the trial. The time between needle insertion and entrance of the left ventricle at the aortic root was recorded. F-test was used to assess significance (P ≤ .05). Results. The time required to accurately position the needle tip at the aortic root decreased significantly over the course of the trial, from 12 minutes with the first attempt to one minute with the last (P = .003). Conclusion. A significant learning curve is encountered when a multidisciplinary team begins a minimally-invasive fetal cardiac intervention program. However, technical proficiency can be achieved with practice. Institutions interested in developing such a program should consider practice in an animal model before proceeding to the human fetus.

Predictors of technical success and postnatal biventricular outcome after in utero aortic valvuloplasty for aortic stenosis with evolving hypoplastic left heart syndrome

BACKGROUND

Aortic stenosis in the midgestation fetus with a normal-sized or dilated left ventricle predictably progresses to hypoplastic left heart syndrome when associated with certain physiological findings. Prenatal balloon aortic valvuloplasty may improve left heart growth and function, possibly preventing evolution to hypoplastic left heart syndrome.

METHODS AND RESULTS

Between March 2000 and October 2008, 70 fetuses underwent attempted aortic valvuloplasty for critical aortic stenosis with evolving hypoplastic left heart syndrome. We analyzed this experience to determine factors associated with procedural and postnatal outcome. The median gestational age at intervention was 23 weeks. The procedure was technically successful in 52 fetuses (74%). Relative to 21 untreated comparison fetuses, subsequent prenatal growth of the aortic and mitral valves, but not the left ventricle, was improved after intervention. Nine pregnancies (13%) did not reach a viable term or preterm birth. Seventeen patients had a biventricular circulation postnatally, 15 from birth. Larger left heart structures and higher left ventricular pressure at the time of intervention were associated with biventricular outcome. A multivariable threshold scoring system was able to discriminate fetuses with a biventricular outcome with 100% sensitivity and modest positive predictive value.

CONCLUSIONS

Technically successful aortic valvuloplasty alters left heart valvar growth in fetuses with aortic stenosis and evolving hypoplastic left heart syndrome and, in a subset of cases, appeared to contribute to a biventricular outcome after birth. Fetal aortic valvuloplasty carries a risk of fetal demise. Fetuses undergoing in utero aortic valvuloplasty with an unfavorable multivariable threshold score at the time of intervention are very unlikely to achieve a biventricular circulation postnatally.

Advances in paediatric interventional cardiology since 2000

Interventional paediatric and congenital cardiology is expanding at a rapid pace. Validated techniques (such as aortic or pulmonary valve dilatations and occlusion of persistent ductus arteriosus and atrial septal defects) are improving thanks to the use of smaller introducers and sheaths, low-profile balloons and novel devices. Moreover, catheter-based interventions have emerged as an attractive alternative to surgery in other fields: pulmonary valve replacement, balloon and stent implantation for native and recurrent coarctation, and percutaneous closure of ventricular septal defects. On the other hand, percutaneous interventions in the paediatric population may be limited by patient size or the anatomy of the defect. Hybrid approaches involving both cardiac interventionists and surgeons are being developed to overcome these limitations. Based on a better understanding of cardiac development, fetal cardiac interventions are being attempted in order to alter the history of severe obstructive lesions. Finally, some interventional procedures still carry a low success rate-for example, pulmonary vein stenosis, even with the use of conventional stents. Biodegradable stents and devices are being developed and may find an application in this setting as well as in others. The purpose of this review is to highlight the advances in paediatric interventional cardiology since the beginning of the third millennium.

The role of fetal echocardiography in fetal intervention: a symbiotic relationship

In this review, the authors explore the role of noninvasive and invasive fetal interventions in fetal cardiovascular disease guided by observations at fetal echocardiography. They first review fetal cardiac lesions that may be ameliorated by fetal intervention and then review noncardiac fetal pathologic findings for which fetal echocardiography can provide important insight into the pathophysiology and aid in patient selection for and timing of intervention and postintervention surveillance.

Fetal intervention for cardiac disease: the cutting edge of perinatal care

Fetal cardiac valvuloplasty has been proposed for progressive cardiac disease with a poor prognosis, such as critical aortic stenosis and pulmonary atresia with intact ventricular septum and balloon atrial septostomy for hypoplastic left heart syndrome, or simple transposition of the great arteries with closed or restrictive inter-atrial communication. It is anticipated that early rescue of ventricles or the pulmonary veins from an unfavourable environment may promote healthier ventricular and vascular growth and improve postnatal outcomes. While close collaboration between the fetal medicine specialist and perinatal cardiologist may optimize the chances of technical success, obstacles to progress include the relative rarity of suitable cases and late referral for therapy. In common with other interventions in fetal medicine, there is a learning curve, and it would benefit progress if the procedures were initially concentrated in just a few centres to enable them to develop skills and experience. Following careful evaluation, it may then be desirable to train further centres and roll out best practice models.

Pathophysiology, management, and outcomes of fetal hemodynamic instability during prenatal cardiac intervention

Prenatal cardiac intervention (PCI) may favorably alter the in utero course of some congenital heart defects. In our preliminary experience with PCI, fetal hemodynamic instability (FHI) characterized by bradycardia and ventricular dysfunction was common. This study evaluated the pathophysiology, management, and short-term outcomes of FHI during PCI for aortic stenosis with evolving hypoplastic left heart syndrome (HLHS), HLHS with restrictive atrial septum, pulmonary atresia with intact ventricular septum, and hydrops due to structural heart disease. From 2000 to 2006, 83 fetuses underwent PCI, with ventricular access in 63, atrial access in 17, and both in three. FHI occurred in 37 fetuses (45%). FHI was associated with transventricular PCI (all but one case of FHI; p < 0.001) and large hemopericardium (n=9; p=0.07). Prolonged FHI was associated with severe ventricular distortion during ventricular puncture (p = 0.06). FHI was treated with resuscitation medications in 31 of 37 fetuses and resolved in all 37. Five fetuses died within 1 d of PCI: four had FHI and one had a massive hemopericardium. FHI is common and clinically important during transventricular PCI and may be caused by a ventricular reflex or reduced cardiac output from cardiac distortion during ventricular puncture. Hemopericardium may be causative in a subset of fetuses.

In-utero intervention for severe congenital heart disease

The concept of fetal therapy is well established for many disorders diagnosed before birth but practical issues regarding its introduction into clinical practice are more difficult. Cardiac malformations are common, with major lesions affecting about 3.5 per thousand pregnancies; however, only a small proportion of these is likely to benefit from an intrauterine intervention. In addition, there are no good animal models of human cardiac disease and our knowledge of the underlying mechanisms is at best sketchy. This combination of factors has resulted in slow progress in developing effective therapies for the intrauterine management of cardiac disease. Recent research and clinical developments have included percutaneous valvuloplasty for severe aortic and pulmonary stenosis, perforation of the closed or restrictive inter-atrial septum and pacing for complete heart block. Progress in these endeavours has been variable but - overall - shows promise for treatment of the human fetus.

Computer-assisted navigation applied to fetal cardiac intervention

BACKGROUND

Prenatal cardiac interventions (PCI) for human fetal aortic valve (AoV) stenosis can reduce left ventricular hypoplasia and restore ventricular growth and function. However, 'freehand' needle delivery from the maternal skin through the uterine wall, fetal chest and ventricular apex to cross the fetal AoV remains technically challenging and time intensive, and is the rate-limiting step in the procedure.

METHODS

We developed a computer-assisted navigation (CANav) system that tracks the position and orientation of a two-dimensional (2D) ultrasound image relative to the trajectory of an electromagnetic (EM) embedded needle and stylet. We tested the CANav system in vitro using a water bath phantom, then in vivo using adult rats and pregnant (fetal) sheep.

RESULTS

The CANav system accurately tracked the delivered needle position in both in vitro phantom and adult rat model experiments. We performed 22 PCI attempts with or without CANav in a fetal sheep model. Maternal laparotomy was required to adjust the fetal position in 50% of the procedures. The time required to deliver the needle from the skin into the left ventricle (LV) using CANav was 2.9 +/- 1.7 (range 2-7) min (n = 14) vs. 5.5 +/- 4.3 (range 1-12) min (n = 8) without CANav (p < 0.05). The time needed to cross the aortic valve once the needle was within the LV was similar with and without CANav (p = 0.19).

CONCLUSIONS

CANav reduces the PCI time required to accurately deliver a needle to the fetal heart. Adaptations of this technical approach may be relevant to other congenital cardiac conditions and ultrasound-guided medical procedures.