Progression of fetal heart disease and rationale for fetal intracardiac interventions

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).

Fetal cardiac intervention for right sided heart disease: Pulmonary atresia with intact ventricular septum

Congenital heart disease (CHD), the most common of birth defects, can be serious enough to require a lifetime of medical care including multiple surgeries or other interventions. Advances in ultrasound technology and a better understanding of the progression of CHDs have made it possible to intervene in utero. This early stage intervention allows the still plastic cardiovascular system to return to a more normal trajectory thus sparing the newborn from negative consequences to morbidity and mortality. Fetal cardiac intervention (FCI) has been successful for the alleviation of left ventricular dysfunction resulting in remarkably positive outcomes for many families. Promising results support that FCI may also be useful in alleviating right ventricular dysfunction. This bodes well for expanding the use of FCI to lead to better postnatal adaptation and improved long-term function for more children with CHD.

Fetal cardiology: changing the definition of critical heart disease in the newborn

Infants born with congenital heart disease (CHD) may require emergent treatment in the newborn period. These infants are likely to benefit the most from a prenatal diagnosis, which allows for optimal perinatal planning. Several cardiac centers have created guidelines for the management of these high-risk patients with CHD. This paper will review and compare several prenatal CHD classification systems with a particular focus on the most critical forms of CHD in the fetus and newborn. A contemporary definition of critical CHD is one which requires urgent intervention in the first 24 h of life to prevent death. Such cardiac interventions may be not only life saving for the infant but also decrease subsequent morbidity. Critical CHD cases may require delivery at specialized centers that can provide perinatal, obstetric, cardiology and cardiothoracic surgery care. Fetuses diagnosed in mid-gestation require detailed fetal diagnostics and serial monitoring during the prenatal period, in order to assess for ongoing changes and identify progression to a more severe cardiac status. Critical CHD may progress in utero and there is still much to be learned about how to best predict those who will require urgent neonatal interventions. Despite improved therapeutic capabilities, newborns with critical CHD continue to have significant morbidity and mortality due to compromise that begins in the delivery room. Fetal echocardiography is the best way to predict the need for specialized care at birth to improve outcome. Once the diagnosis is made of critical CHD, delivery at the proper time and in appropriate institution with specific care protocols should be initiated. More work needs to be done to better delineate the risk factors for progression of critical CHD and to determine which newborns will require specialized care. The most frequently described forms of critical CHD requiring immediate intervention include hypoplastic left heart syndrome with intact or severely restricted atrial septum, obstructed total anomalous pulmonary venous return and transposition of the great arteries with restrictive atrial septum.

The study of fetal rat model of intra-amniotic isoproterenol injection induced heart dysfunction and phenotypic switch of contractile proteins

To establish a reliable isoproterenol induced heart dysfunction fetal rat model and understand the switches of contractile proteins, 45 pregnant rats were divided into 15 mg/kg-once, 15 mg/kg-twice, sham-operated once, sham-operated twice, and control groups. And 18 adult rats were divided into isoproterenol-treated and control groups. H&E staining, Masson staining, and transmission electron microscope were performed. Apoptotic rate assessed by TUNEL analysis and expressions of ANP, BNP, MMP-2, and CTGF of hearts were measured. Intra-amniotic injections of isoproterenol were supplied on E14.5 and E15.5 for fetuses and 7-day continuous intraperitoneal injections were performed for adults. Then echocardiography was performed with M-mode view assessment on E18.5 and 6 weeks later, respectively. Isoproterenol twice treated fetuses exhibited significant changes in histological evaluation, and mitochondrial damages were significantly severe with increased apoptotic rate. ANP and BNP increased and that of MMP-2 increased in isoproterenol twice treated group compared to control group, without CTGF. The isoforms transition of troponin I and myosin heavy chain of fetal heart dysfunction were opposite to adult procedure. The administration of intra-amniotic isoproterenol to fetal rats could induce heart dysfunction and the regulation of contractile proteins of fetuses was different from adult procedure.

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.

Diagnosis of congenital heart disease by early and second-trimester fetal echocardiography

OBJECTIVES

The aim of this study was to compare the cardiac findings at 11 to 14 weeks' gestation with the second-trimester findings to evaluate the reliability of first-trimester echocardiography and the possibility of congenital heart disease evolution.

METHODS

The database of our fetal medicine unit was searched for all patients who had undergone fetal echocardiography at 11 to 14 and 18 to 22 weeks' gestation from 2005 to 2010. In all of the antenatally suspected cases of congenital heart disease, the diagnosis was established conclusively by postnatal echocardiography, surgery, or autopsy.

RESULTS

Among the 870 fetuses included in the study, 802 were considered to have no abnormalities on both examinations. Thirty-six cases had abnormal findings on both examinations, and 32 had discordant findings. Among the 32 discordant findings, 6 cases had a false-positive diagnosis of congenital heart disease on early echocardiography, and 26 had a different diagnosis. In 14 of these 26 cases, the diagnosis was slightly different on the second-trimester examination, or the defect misdiagnosed in the first trimester was a minor one. In 6 of the remaining 12 fetuses, a major congenital heart disease was missed on the early echocardiography. In 6 cases, the congenital heart disease developed or progressed in severity in the second trimester.

CONCLUSIONS

First-trimester echocardiography is feasible and seems to allow considerably earlier detection of major congenital heart disease. However, it should be kept in mind that although most forms of heart defects can be diagnosed early in pregnancy, some may develop and become apparent only later in gestation.

Foetal cardiac intervention: an ethical perspective

Although recent advances have helped identify cases where foetal cardiac surgery might reverse the development of certain lesions, the indications and measurement of success in these procedures have yet to be established. Thus, both patients and physicians have a "burden of knowledge", whereby a diagnosis is made without a clear course of action. The profound issues raised by foetal intervention, specifically the question of how concepts such as "patient" and "success" can be used, complicate this burden further and test the limits of language and logic. Similar issues raised in postmodern philosophy are discussed and can be incorporated into foetal cardiac surgery dialogues to produce a multi-disciplinary approach that will elucidate, not obfuscate, these issues in the future.

Update in fetal cardiac intervention

The severity of fetal heart disease progresses during gestation and may lead to significant in utero or postnatal morbidity and mortality. Fetal echocardiography allows us to detect heart disease early enough in pregnancy to perform fetal cardiac intervention that may change the natural history of some diseases. The principal aims are the prevention of hydrops due to congenital heart disease, recruitment of hypoplastic ventricles, remodeling of the fetal pulmonary vascular bed, or creation of a two-ventricular circulation after birth without risk to the mother. The initial fetal interventions for valvuloplasty and atrial septostomy showed a high mortality and did not achieve significant change in the final outcome of patients. Nevertheless, some technique modifications have improved the outcome of these patients, making fetal cardiac intervention a promising treatment for congenital heart disease. Conversely, different assessment tools for selection of the correct patient have been studied in some series to improve the success of these procedures and thus the survival odds. We believe that percutaneous procedures with local anesthesia are preferable.

Current applications of fetal cardiac imaging technology

PURPOSE OF REVIEW

Over the last few years, great progress has been made in imaging technology, which is changing the way prenatal visualization of the fetal heart is used for diagnosis and therapy.

RECENT FINDINGS

This paper reviews recent clinical research using these new techniques, namely dynamic three-dimensional (4D) echocardiography, myocardial Doppler imaging, B-flow ultrasonography, endoscopic ultrasound, and magnetic resonance imaging. Of them, 4D echocardiography is the most significant development and is discussed in greater detail. This includes real-time volumetric data acquisition using matrix-array transducer technology, motion artefact elimination using spatio-temporal image correlation, and various display options. The advantages and limitations of each are also addressed.

SUMMARY

These techniques can provide (1) sequential assessment of the entire heart using a full 4D dataset, (2) 4D delineation of trabeculation patterns on the ventricular walls, en-face dynamic shapes of ventricular septal defects and spatially complex malformations, (3) derivation of cardiac indices to myocardial contractility and strain rate by Doppler tissue imaging, and/or (4) the use of transoesophageal ultrasound to guide in-utero cardiac intervention. All of these techniques expand our ability to evaluate the morphology and function of the in-utero heart.

Genetic factors in congenital heart malformation

Congenital heart disease is the commonest malformation in humans and contributes greatly to the burden of disease in infancy. Increasingly, developmental origins are also implicated in heart disease in adults. Significant advances have been made over the past decade in elucidating morphogenetic events of heart formation and their underlying molecular cascades, mostly in animal models. Clinical studies are increasingly successful in quantifying and unraveling genetic factors. This review focuses on recent progress made in understanding the genetic underpinnings of normal and abnormal heart formation and highlights the importance of understanding these mechanisms to improve patient management.

Controversies of fetal cardiac intervention

Remarkable advances in ultrasound imaging technology have made it possible to diagnose fetal cardiovascular lesions as early as 12-14 weeks of gestation and to assess their physiological relevance by echocardiography. Moreover, invasive techniques have been developed and refined to relieve significant congenital heart disease (CHD), such as critical aortic and pulmonary stenoses in the pediatric population including neonates. Recognition of the fact that certain CHDs can evolve in utero, and early intervention may improve the outcome by altering the natural history of such conditions has led to the evolution of a new fetal therapy, i.e. fetal cardiac intervention. Two entities, pulmonary valvar atresia and intact ventricular septum (PA/IVS) and hypoplastic left heart syndrome (HLHS), are associated with significant morbidity and mortality even with postnatal surgical therapy. These cases are believed to occur due to restricted blood flow, leading to impaired growth and function of the right or left ventricle. Therefore, several centers started the approach of antenatal intervention with the primary goal of improving the blood flow through the stenotic/atretic valve orifices to allow growth of cardiac structures. Even though centers with a reasonable number of cases seem to have improved the technique and the immediate outcome of fetal interventions, the field is challenged by ethical issues as the intervention puts both the mother and the fetus at risk. Moreover, the perceived benefits of prenatal treatment have to be weighed against steadily improving postnatal surgical and hybrid procedures, which have been shown to reduce morbidity and mortality for these complex heart defects. This review is an attempt to provide a balanced opinion and an update on fetal cardiac intervention.

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.

Hydrops foetus universalis – a retrospective study

A szerzők a hydrops foetus előfordulási gyakoriságát, létrejöttének okait vizsgálták. Öt év alatt 555 foetalis és neonatális autopsziás vizsgálatot végeztek. Hydropsot igazoltak 28 magzatnál. Három esetben Rh-izoimmunizáció állt a háttérben, 25 foetusnál nem immun hydrops került megállapításra. Huszonöt esetben sikerült a hydrops kiváltó okát tisztázni, az ok 3 esetben felderítetlen maradt. Tizenkét esetben középidős spontán vetélés, illetve in utero elhalás történt, míg 12 foetusnál orvosi indok alapján történt a terhesség terminálása. Emellett 4 újszülöttkorban meghalt beteget is vizsgáltak. Az orvosi indok alapján történő terhességmegszakításnál a foetusok átlagos kora a 16. és a 20. gesztációs hét között volt, míg a középidős spontán vetélés és in utero elhalás esetén ez a 24. terhességi hetet jelentette. A patológiai vizsgálat valamennyi esetben a terhességi korhoz képest várható testsúlynövekedését, periferiás oedemát, ascitest, illetve hydrothoraxot igazolt. Az esetek felében hydropericardium is látható volt. Hepatosplenomegália, cardiomegália, pulmonális hypoplasia, fokozott extramedulláris hemopoezis, placenta oedema valamennyi esetben megfigyelhető volt. A nem immun hydrops hátterében a következő rendellenességeket találták: 4 esetben cardiális malformatiót, 1 esetben szkeletális rendellenességet, 3 foetusnál kromoszómarendellenességet, 2 foetusnál cysticus hygromát, 3 esetben iker-iker transzfúzióval járó monochorialis diamnialis ikerterhességet, 7 esetben infekciót, 1 foetusnál sacrococcygeális teratomát. Két esetben a kiváltó ok anyai betegséget jelentett. A klinikai és patológiai diagnózisokat összehasonlítva megállapították, hogy a nem immun hydrops kórokával kapcsolatban csupán 3 esetben volt teljes egyezés a klinikai véleménnyel. A patológiai vizsgálat által feltárt kórokot az öröklődés, terápiás lehetőségek mérlegelése szempontjából 10 esetben szignifikánsnak véleményezték. A szerzők kiemelik nem immun hydrops esetén a részletes patológiai vizsgálat szükségességét, a klinikai vizsgálatokkal való korreláció meghatározásának fontosságát, a szerológiai vizsgálatok jelentőségét és a társszakmákkal való együttműködés szükségességet a hydropsos magzatokkal kapcsolatos további teendők meghatározása érdekében.