Fetal aortic valvuloplasty may rescue fetuses with critical aortic stenosis and hydrops.

OBJECTIVE: Critical aortic stenosis (CAS) with a restrictive interatrial septum may lead to fetal congestive heart failure and hydrops, usually culminating in fetal demise if left untreated. The aim of this study was to assess the effects of fetal aortic valvuloplasty (FAV) on hemodynamics and outcome in these patients. METHODS: This was a retrospective review of fetuses with CAS and signs of hydrops that underwent FAV in our center between 2000 and 2020. Echocardiograms and patients' charts were analyzed for ventricular and valvular dimensions and for outcome. RESULTS: Hydrops was present at the time of intervention in 15 fetuses with CAS that underwent FAV at our center during the study period. All but one patient had at least one technically successful procedure. There were no procedure-related deaths, but three intrauterine deaths occurred. Twelve subjects were liveborn, of whom two died within 24 h after birth owing to persistent hydrops. Ventricular function improved and hydrops resolved within 3-4 weeks after FAV in 71.4% (10/14) of fetuses with a technically successful intervention. A biventricular outcome was achieved in 50% of the successfully treated patients. CONCLUSIONS: Fetuses with CAS and hydrops can be successfully treated with FAV. The procedure has the potential to restore sufficient fetal cardiac output, which may lead to resolution of hydrops. Surviving patients seem to be good candidates for a biventricular outcome. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal cardiac filling and ejection time fractions by pulsed-wave Doppler: reference ranges and potential clinical application.

OBJECTIVES: Fetal cardiac function can be evaluated using a variety of parameters. Among these, cardiac cycle time-related parameters, such as filling time fraction (FTF) and ejection time fraction (ETF), are promising but rarely studied. We aimed to report the feasibility and reproducibility of fetal FTF and ETF measurements using pulsed-wave Doppler, to provide reference ranges for fetal FTF and ETF, after evaluating their relationship with heart rate (HR), gestational age (GA) and estimated fetal weight (EFW), and to evaluate their potential clinical utility in selected fetal conditions. METHODS: This study included a low-risk prospective cohort of singleton pregnancies and a high-risk population of fetuses with severe twin-twin transfusion syndrome (TTTS), aortic stenosis (AoS) or aortic coarctation (CoA), from 18 to 41 weeks' gestation. Left ventricular (LV) and right ventricular inflow and outflow pulsed-wave Doppler signals were analyzed, using valve clicks as landmarks. FTF was calculated as: (filling time/cycle time) × 100. ETF was calculated as: (ejection time/cycle time) × 100. Intraclass correlation coefficients (ICC) were used to evaluate the intra- and interobserver reproducibility of FTF and ETF measurements in low-risk fetuses. The relationships of FTF and ETF with HR, GA and EFW were evaluated using multivariate regression analysis. Reference ranges for FTF and ETF were then constructed using the low-risk population. Z-scores of FTF and ETF in the high-risk fetuses were calculated and analyzed. RESULTS: In total, 602 low-risk singleton pregnancies and 54 high-risk fetuses (nine pairs of monochorionic twins with severe TTTS, 16 fetuses with AoS and 20 fetuses with CoA) were included. Adequate Doppler traces for FTF and ETF could be obtained in 95% of low-risk cases. Intraobserver reproducibility was good to excellent (ICC, 0.831-0.905) and interobserver reproducibility was good (ICC, 0.801-0.837) for measurements of all timing parameters analyzed. Multivariate analysis of FTF and ETF in relation to HR, GA and EFW in low-risk fetuses identified HR as the only variable predictive of FTF, while ETF was dependent on both HR and GA. FTF increased with decreasing HR in low-risk fetuses, while ETF showed the opposite behavior, decreasing with decreasing HR. Most recipient twins with severe TTTS showed reduced FTF and preserved ETF. AoS was associated with decreased FTF and increased ETF in the LV, with seemingly different patterns associated with univentricular vs biventricular postnatal outcome. The majority of fetuses with CoA had FTF and ETF within the normal range in both ventricles. CONCLUSIONS: Measurement of FTF and ETF using pulsed-wave Doppler is feasible and reproducible in the fetus. The presented reference ranges account for associations of FTF with HR and of ETF with HR and GA. These time fractions are potentially useful for clinical monitoring of cardiac function in severe TTTS, AoS and other fetal conditions overloading the heart. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Identification of a peripheral blood gene signature predicting aortic valve calcification.

Calcific aortic valve disease (CAVD) is a significant cause of illness and death worldwide. Identification of early predictive markers could help optimize patient management. RNA-sequencing was carried out on human fetal aortic valves at gestational weeks 9, 13, and 22 and on a case-control study with adult noncalcified and calcified bicuspid and tricuspid aortic valves. In dimension reduction and clustering analyses, diseased valves tended to cluster with fetal valves at week 9 rather than normal adult valves, suggesting that part of the disease program might be due to reiterated developmental processes. The analysis of groups of coregulated genes revealed predominant immune-metabolic signatures, including innate and adaptive immune responses involving lymphocyte T-cell metabolic adaptation. Cytokine and chemokine signaling, cell migration, and proliferation were all increased in CAVD, whereas oxidative phosphorylation and protein translation were decreased. Discrete immune-metabolic gene signatures were present at fetal stages and increased in adult controls, suggesting that these processes intensify throughout life and heighten in disease. Cellular stress response and neurodegeneration gene signatures were aberrantly expressed in CAVD, pointing to a mechanistic link between chronic inflammation and biological aging. Comparison of the valve RNA-sequencing data set with a case-control study of whole blood transcriptomes from asymptomatic individuals with early aortic valve calcification identified a highly predictive gene signature of CAVD and of moderate aortic valve calcification in overtly healthy individuals. These data deepen and broaden our understanding of the molecular basis of CAVD and identify a peripheral blood gene signature for the early detection of aortic valve calcification.

Clinical and Hemodynamic Results After Conversion from Single to Biventricular Circulation After Fetal Aortic Stenosis Intervention.

At our institution a multidisciplinary team has performed fetal aortic valvuloplasty (FAV) for severe aortic stenosis with evolving hypoplastic left heart syndrome with high technical success rates. Measurement of postnatal success has been biventricular circulation (BC). Postnatal survival for patients after FAV who achieved a BC appears encouraging. However, there are limited late clinical and hemodynamic outcomes in this cohort and there is concern for diastolic dysfunction. We reviewed all patients with FAV at our institution who initially underwent single ventricle palliation and subsequently BC, as this is likely the subset at high-risk for poor outcomes. Clinical, imaging, and surgical data were collected. Two of 7 patients (29%) died within 16 months of BC, and 1 patient has been listed for transplant. Diastolic dysfunction was common and progressive with median left ventricular end diastolic pressure of 12 mm Hg before BC, and increasing to 22 mm Hg for survivors at last follow-up. Left ventricular size was adequate with all patients reaching a left ventricular end diastolic volume (LVEDV) z score in the normal or elevated range. Presence and severity of residual valve lesions decreased over time secondary to a median of 6 interventions (range 3 to 10), either surgical or cath-based, performed for these 7 patients during the study period. In conclusion, clinical outcomes are concerning for this high-risk group. Diastolic dysfunction is persistent and progressive despite anatomic interventions and adequate left ventricular growth. The main contributing factor to poor outcomes may be intrinsic myocardial dysfunction and primordial pathology. Achievement of a BC after FAV may not be an appropriate measure of success.

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.

Fetal hemodynamic response to aortic valvuloplasty and postnatal outcome: a European multicenter study.

OBJECTIVE: Fetal aortic stenosis may progress to hypoplastic left heart syndrome. Fetal valvuloplasty (FV) has been proposed to improve left heart hemodynamics and maintain biventricular (BV) circulation. The aim of this study was to assess FV efficacy by comparing survival and postnatal circulation between fetuses that underwent FV and those that did not. METHODS: This was a retrospective multicenter study of fetuses with aortic stenosis that underwent FV between 2005 and 2012, compared with contemporaneously enrolled natural history (NH) cases sharing similar characteristics at presentation but not undergoing FV. Main outcome measures were overall survival, BV-circulation survival and survival after birth. Secondary outcomes were hemodynamic change and left heart growth. A propensity score model was created including 54/67 FV and 60/147 NH fetuses. Analyses were performed using logistic, Cox or linear regression models with inverse probability of treatment weighting (IPTW) restricted to fetuses with a propensity score of 0.14-0.9, to create a final cohort for analysis of 42 FV and 29 NH cases. RESULTS: FV was technically successful in 59/67 fetuses at a median age of 26 (21-34) weeks. There were 7/72 (10%) procedure-related losses, and 22/53 (42%) FV babies were delivered at < 37 weeks. IPTW demonstrated improved survival of liveborn infants following FV (hazard ratio, 0.38; 95% CI, 0.23-0.64; P = 0.0001), after adjusting for circulation and postnatal surgical center. Similar proportions had BV circulation (36% for the FV cohort and 38% for the NH cohort) and survival was similar between final circulations. Successful FV cases showed improved hemodynamic response and less deterioration of left heart growth compared with NH cases (P ≤ 0.01). CONCLUSIONS: We report improvements in fetal hemodynamics and preservation of left heart growth following successful FV compared with NH. While the proportion of those achieving a BV circulation outcome was similar in both cohorts, FV survivors showed improved survival independent of final circulation to 10 years' follow-up. However, FV is associated with a 10% procedure-related loss and increased prematurity compared with the NH cohort, and therefore the risk-to-benefit ratio remains uncertain. We recommend a carefully designed trial incorporating appropriate and integrated fetal and postnatal management strategies to account for center-specific practices, so that the benefits achieved by fetal therapy vs surgical strategy can be demonstrated clearly. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Notch-Tnf signalling is required for development and homeostasis of arterial valves.

AIMS: Congenital anomalies of arterial valves are common birth defects, leading to valvar stenosis. With no pharmaceutical treatment that can prevent the disease progression, prosthetic replacement is the only choice of treatment, incurring considerable morbidity and mortality. Animal models presenting localized anomalies and stenosis of congenital arterial valves similar to that of humans are critically needed research tools to uncover developmental molecular mechanisms underlying this devastating human condition. METHODS AND RESULTS: We generated and characterized mouse models with conditionally altered Notch signalling in endothelial or interstitial cells of developing valves. Mice with inactivation of Notch1 signalling in valvar endothelial cells (VEC) developed congenital anomalies of arterial valves including bicuspid aortic valves and valvar stenosis. Notch1 signalling in VEC was required for repressing proliferation and activating apoptosis of valvar interstitial cells (VIC) after endocardial-to-mesenchymal transformation (EMT). We showed that Notch signalling regulated Tnfα expression in vivo, and Tnf signalling was necessary for apoptosis of VIC and post-EMT development of arterial valves. Furthermore, activation or inhibition of Notch signalling in cultured pig aortic VEC-promoted or suppressed apoptosis of VIC, respectively. CONCLUSION: We have now met the need of critical animal models and shown that Notch-Tnf signalling balances proliferation and apoptosis for post-EMT development of arterial valves. Our results suggest that mutations in its components may lead to congenital anomaly of aortic valves and valvar stenosis in humans.

[Fetal cardiac interventions - are we ready for them?]. / Interwencyjne zabiegi kardiologiczne u plodów - czy jestesmy do nich przygotowani?

OBJECTIVE: The aim of the study was to analyze types and methods of intrauterine fetal cardiac interventions performed between June 2011 and December 2013, and to assess the perinatal management of the neonates. METHODS: The program was developed after analysis of the available literature, practical individual training in Linz, Austria, and simulation of the procedure in a dissecting-room. The rules for anesthesia in pregnant women and their fetuses were developed. The interventions were performed in fetuses with critical cardiac defects, in the operating room, under ultrasonographic control. The protocol was approved by the Local Bioethics Committee at the Centre of Postgraduate Medical Education. MATERIAL: We included fetuses with critical aortic stenosis (n=29), critical pulmonary stenosis (n=2), and closed or extremely restricted foramen ovale (n=7). Between June 2011 and December 2013, the team comprised of JD, MD and AK conducted 42 interventions in 35 fetuses, including 32 balloon aortic valvuloplasties (in 29 fetuses), 2 pulmonary valvuloplasties, 4 balloon atrial septostomies and 4 atrial septal stent placement. Three fetuses required both, aortic valvuloplasty and fenestration of the atrial septum. RESULTS: Out of the 42 procedures, 41 (97%) were technically successful. We recorded 3 cases of fetal demise associated with the intervention. We modulated the protocol of anesthesia given to pregnant women, switching from general to local anesthesia with intravenous sedation. We always provided additional fetal anesthesia with fentanyl and atracurium via the umbilical vein. CONCLUSIONS: Based on our 2.5-year experience, it seems safe to conclude that all types of fetal cardiac interventions may be successfully conducted at Polish centers. The procedures are safe for the pregnant women and improve fetal status. Most of the neonates treated prenatally were referred in good general condition to a tertiary pediatric cardiology and cardiac surgery center

Fetal critical aortic stenosis with natural improvement of hydrops fetalis due to spontaneous relief of severe restrictive atrial communication.

We describe a rare case of fetal critical aortic stenosis with spontaneous relief of severe restrictive atrial communication, resulting in complete resolution of hydrops fetalis in utero. Fetal ultrasonography showed hydrops fetalis caused by critical aortic stenosis with a severely restrictive foramen ovale and severe mitral regurgitation at 23 weeks of gestation. Hydrops fetalis, however, spontaneously resolved, showing an obvious increase of flow through the foramen ovale and pulmonary vein at 26 weeks of gestation. The neonate required balloon dilation of the aortic valve and balloon atrioseptostomy immediately after birth and also received bilateral pulmonary artery banding and arterial duct stenting 1 week later. The patient was in good condition after conversion to biventricular circulation via Ross procedure at 8 months old. The present case suggests that atrioseptostomy as a fetal intervention may improve outcome in even a hydropic condition.

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.

[Prenatal diagnosis of fetal aortic stenosis with mitral insufficiency. Review of the ultrasound diagnosis and perinatal prognosis: a case report]. / Diagnóstico prenatal de la estenosis aórtica crítica con insuficiencia mitral. Revisión del diagnóstico ecográfico y pronóstico perinatal. A propósito de un caso.

This is a report about a case of prenatal diagnosis of critical fetal aortic stenosis with severe mitral valve insufficiency in a 35+6 weeks fetus. Aortic stenosis represents 3% of congenital heart diseases, but its association with mitral regurgitation is quite unusual. Thanks to the latest advances in fetal ultrasonography we can now achieve a more precise diagnosis and we have been able to improve the understanding of its physiopathology. Based on this case we have reviewed the most recent literature about fetal aortic stenosis and mitral valve insufficiency, with the aim of summarizing its main physiopathological features, highlighting the clues and key points for its intrauterine diagnosis, describing its principal complications and summarizing its current treatment options.

Fetal aortic valvuloplasty: investigating institutional bias in surgical decision-making.

OBJECTIVES: Fetal aortic valvuloplasty may prevent the progression of aortic stenosis to hypoplastic left heart syndrome and allow biventricular rather than univentricular postnatal treatment. This study aimed to investigate whether blinded simulation of a multidisciplinary team approach aids interpretation of multicenter data to uncover institutional bias in postnatal decision-making following fetal cardiac intervention for aortic stenosis. METHODS: The study included 109 cases of prenatally diagnosed aortic stenosis from 13 European countries, of which 32 had undergone fetal cardiac intervention. The multidisciplinary team, blinded to fetal cardiac intervention, institutional location and postnatal treatment, retrospectively assigned a surgical pathway (biventricular or univentricular) based on a review of recorded postnatal imaging and clinical characteristics. The team's decisions were the numerical consensus of silent voting, with case review when a decision was split. Funnel plots showing concordance between the multidisciplinary team and the local team's surgical choice (first pathway) and with outcome (final pathway) were created. RESULTS: In 105 cases the multidisciplinary team reached a consensus decision regarding the surgical pathway, with no decision in four cases because the available imaging records were inadequate. Blinded multidisciplinary team consensus for the first pathway matched the decision of the surgical center in 93/105 (89%) cases, with no difference in agreement between those that had undergone successful fetal cardiac intervention (n = 32) and no (n = 74) or unsuccessful (n = 3) valvuloplasty (no fetal cardiac intervention) (κ = 0.73 (95% CI, 0.38-1.00) vs 0.74 (95% CI, 0.51-0.96)). However, funnel plots comparing multidisciplinary team individual decisions with those of the local teams displayed more discordance (meaning biventricular-univentricular conversion) for the final surgical pathway following fetal cardiac intervention than they did for cases without such intervention (36/74 vs 34/130; P = 0.002), and identified one outlying center. CONCLUSIONS: The use of a blinded multidisciplinary team to simulate decision-making and presentation of data in funnel plots may assist in the interpretation of data submitted to multicenter studies and permit the identification of outliers for further investigation. In the case of aortic stenosis, a high level of agreement was observed between the multidisciplinary team and the surgical centers, but one outlying center was identified.

Cadherin-11 expression patterns in heart valves associate with key functions during embryonic cushion formation, valve maturation and calcification.

Proper fibroblast cell migration and differentiation are critical for valve formation and homeostasis, but uncontrolled myofibroblastic activation may precede osteogenic differentiation and calcification. Cadherin-11 (cad-11) is a cell-cell adhesion protein classically expressed at mesenchymal-osteoblast interfaces that participates in mesenchymal differentiation to osteochondral lineages. This suggests cad-11 may have an important role in heart valve development and pathogenesis, but its expression patterns in valves are largely unknown. In this study, we profiled the spatial and temporal expression patterns of cad-11 in embryonic chick and mouse heart development. We determined that cad-11 is expressed in both endocardial and mesenchymal cells of the atrioventricular and outflow tract cushions (pre-HH30/E14), but becomes restricted to the valve endocardial/endothelial cells during late fetal remodeling and throughout postnatal life. We then investigated changes in cad-11 expression in a murine aortic valve disease model (the ApoE(-/-)). Unlike wild-type mice, cad-11 becomes dramatically re-expressed in the interstitium. Similarly, in calcified human aortic valve leaflets, cad-11 loses endothelial confinement and becomes significantly re-expressed in the valve interstitium. Double labeling identified that 91% of myofibroblastic and 96% of osteoblastic cells in calcified aortic valves were also cad-11 positive. Collectively, our results suggest that cad-11 is important for proper embryonic cushion formation and remodeling, but may also participate in aortic valve pathogenesis if re-expressed in adulthood.

Balloon valvuloplasty for critical aortic stenosis in a fetus: a case report.

The mortality and morbidity of fetal aortic stenosis (AS) depend on the degree of the hemodynamic effects of the stenosis, and left ventricular (LV) adaptation, development and function during fetal life. In the case of critical AS, the development of hydrops and death in utero are well recognized entities. A 23-week gestation fetus was diagnosed with critical severe AS, cardiomegaly, a dilated LV with very poor contractility, and mitral regurgitation. There was a reversal of flow in the aortic arch through the ductus arteriosis and a reversed a-wave in the ductus venosus on Doppler examination. The fetus had hydrops with ascites, and massive scalp, face and skin edema. Fetal amniocentesis was normal. Aortic valvuloplasty was performed under general anesthesia and echocardiographic guidance. Pericardial effusion was not observed after the procedure. However, LV function could not be ameliorated and continued to diminish. There was no cardiac activity in the fetus two hours after the intervention. Aortic valvuloplasty in utero for AS is technically feasible. Mortality is mainly associated with technical errors, LV function, and the degree of endofibroelastosis in the effected fetuses.

Endothelial deletion of ADAM17 in mice results in defective remodeling of the semilunar valves and cardiac dysfunction in adults.

Global inactivation of the metalloproteinase ADAM17 during mouse development results in perinatal lethality and abnormalities of the heart, including late embryonic cardiomegaly and thickened semilunar and atrioventricular valves. These defects have been attributed in part to a lack of ADAM17-mediated processing of HB-EGF, as absence of soluble HB-EGF results in similar phenotypes. Because valvular mesenchymal cells are largely derived from cardiac endothelial cells, we generated mice with a floxed Adam17 allele and crossed these animals with Tie2-Cre transgenics to focus on the role of endothelial ADAM17 in valvulogenesis. We find that although hearts from late-stage embryos with ablation of endothelial ADAM17 appear normal, an increase in valve size and cell number is evident, but only in the semilunar cusps. Unlike Hbegf(-/-) valves, ADAM17-null semilunar valves do not differ from controls in acute cell proliferation at embryonic day 14.5 (E14.5), suggesting compensatory processing of HB-EGF. However, levels of the proteoglycan versican are significantly reduced in mutant hearts early in valve remodeling (E12.5). After birth, aortic valve cusps from mutants are not only hyperplastic but also show expansion of the glycosaminoglycan-rich component, with the majority of adults exhibiting aberrant compartmentalization of versican and increased deposition of collagen. The inability of mutant outflow valve precursors to transition into fully mature cusps is associated with decreased postnatal viability, progressive cardiomegaly, and systolic dysfunction. Together, our data indicate that ADAM17 is required in valvular endothelial cells for regulating cell content as well as extracellular matrix composition and organization in semilunar valve remodeling and homeostasis.

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.

[The first successful fetal aortic balloon valvuloplasty in Poland]. / Pierwsza w Polsce skuteczna przezskórna plastyka balonowa zastawki aortalnej u plodu.

Prenatal aortic valvuloplasty is performed only in few perinatal centers in the world. Critical aortic stenosis which can lead to hypoplastic left heart syndrome or severe fetal heart failure with nonimmune hydrops is an indication for this procedure. Prenatal intervention can change the natural course of the disease. Authors present the first successful fetal balloon aortic valvuloplasty in Poland. It was performed in a 29-week fetus with critical aortic stenosis, severe impairment of left ventricular function, heart failure and fetal hydrops. After successful intervention, without any complications, left ventricular function and fetal condition improved gradually Effective fetal intervention was possible after few months of preparation and building a team of specialists. This is the first successful fetal cardiac intervention in Poland, which opens the way to the new era of fetal cardiology and hopefully will lead to improve results in children with this critical heart defect.

GATA5 interacts with GATA4 and GATA6 in outflow tract development.

Members of the GATA family of transcription factors are critical regulators of heart development and mutations in 2 of them, GATA4 and GATA6 are associated with outflow tract and septal defects in human. The heart expresses 3 GATA factors, GATA4, 5 and 6 in a partially overlapping pattern. Here, we report that compound Gata4/Gata5 and Gata5/Gata6 mutants die embryonically or perinatally due to severe congenital heart defects. Almost all Gata4(+/-)Gata5(+/-) mutant embryos have double outlet right ventricles (DORV), large ventricular septal defects (VSD) as well as hypertrophied mitral and tricuspid valves. Only 25% of double compound Gata4/Gata5 heterozygotes survive to adulthood and these mice have aortic stenosis. Compound loss of a Gata5 and a Gata6 allele also leads to DORVs associated with subaortic VSDs. Expression of several transcription factors important for endocardial and myocardial cell differentiation, such as Tbx20, Mef2c, Hey1 and Hand2, was reduced in compound heterozygote embryos. These findings suggest the existence of important genetic interactions between Gata5 and the 2 other cardiac GATA factors in endocardial cushion formation and outflow tract morphogenesis. The data identify GATA5 as a potential genetic modifier of congenital heart disease and provide insight for elucidating the genetic basis of an important class of human birth defects.