Perinatal Cardiology-Part 2

Congenital heart diseases (CHDs) are largely known as an important cause of fetal perinatal mortality. Currently, the accuracy of fetal echocardiography enables the detailed diagnosis of a significant variety of congenital cardiac anomalies, and it has also been demonstrated that prenatal outcomes may improve in critical CHDs. Accordingly, this chapter provides a detailed overview of the important anatomic aspects of some of the ventricular inflow anomalies, focusing on currently available information, to enable the prenatal diagnosis of such CHDs by ultrasound or echocardiography. Information regarding prenatal management, delivery plan strategies, and differential diagnosis of such anomalies is presented. The chapter also discusses the parental counseling and fetal and neonatal therapeutic management of such congenital cardiac anomalies. Univentricular atrioventricular (AV) connections, straddling and overriding of AV valves, and crisscross hearts are described in the current chapter. The concept of “functionally single ventricle” encompasses a group of CHDs in which the dominant ventricular chamber is responsible for maintaining the systemic and pulmonary circulations and not suitable for a biventricular repair. The central feature of such hearts is the univentricular AV connection. Regarding the type of the straddling of an inlet valve, it is based on the insertion of the tension apparatus of the AV valve into the crest of the ventricular septum or in the contralateral ventricle. Meanwhile, overriding of an inlet valve is related to the annulus of the AV valve and may interfere in the AV connection. Depending on the degree of the overriding of the straddled valve, the ventricles are in a dominant and rudimentary relationship, and a double-inlet AV connection, primarily the double-inlet left ventricle is the most frequent type of AV connection. In general, straddling and overriding of an AV valve requires a ventricular septal defect, and straddling may occur alone or in the presence of an overriding. In “crisscross” hearts, the ventricular inlet flows are in a cross shape and the ventricles are arranged in a superoinferior relationship. During an ultrasound examination, the crossed AV valves produce false images of the mitral valve or tricuspid atresia in a standard 4-chamber view, which makes the diagnosis difficult. In fact, the knowledge about the detailed anatomy, the assessment of the ventricular outflow tracts, and the identification of other possible associated cardiac anomalies are important for improving In Utero and postnatal management in ventricular inlet anomalies described in the current chapter.

This chapter provides an overview of the most frequent pathologies of the myocardium and pericardium during fetal life. Considering that some of these pathologies constitute a group of uncommon conditions, they are of interest from the point of view of their prognostic and therapeutic value. Besides, they are also within the most striking pathologies found in the screening of the fetal heart, and the ones which cause greater anxiety in the family and professional environment. Progress has been made in different diagnostic techniques, outlining some therapeutic advancements, as well as in the importance of new technologies that allow to deepen our knowledge of the functional defects of the cardiac muscle during fetal life.

Fetal cardiac tumors (FCT) are rare anomalies (about 1% among prenatal cardiac problems). There are more frequent multiple FCT and less frequent single FCT. The FCT occur in the population of healthy young mothers and risk factors are not easily detectable, but environmental factors (benzapirin?) could play a role. Basic ultrasound (US) anatomy in the 1st and 2nd trimester usually is normal and FCT are usually detected in the second half of pregnancy. In the majority of cases the fetus’s growth is normal. In each case, targeted fetal echocardiography should be performed in a fetal cardiology center. The very first problem is to discriminate between normal heart anatomy and congenital heart defect. The second goal of fetal echocardiography in FCT is to make an assessment of the hemodynamic status of the fetus. Extracardiac and additional anomalies coexisting in cases of FTC can be divided into two types i.e., frequent and rare. An experienced fetal cardiologist can not only make a proper diagnosis but also should counsel parents about the short-term prognosis for the fetus (about his future during prenatal life) as well as long term prognosis (after birth and later on). In cases of maternal decision to continue the pregnancy, fetal echocardiography monitoring should be offered to evaluate possible hemodynamic changes, to prepare both fetus and pregnant woman for optimal time for delivery and perinatal care. The main goal would be to avoid prematurity and to confirm fetal wellbeing, despite the cardiac abnormality. Details of echocardiography and postnatal outcome are presented in rhabdomyoma, teratoma, fibroma, myxoma and hemangioma. The way of delivery in surgical resection of cardiac tumors in newborns is discussed. In differential diagnosis, “bright spot” is discussed. Suggested management – algorithm of perinatal care in cases of FCT is presented with emphasis on cooperation of a perinatal team. FCT can be diagnosed at 20 weeks of pregnancy, which allows to start echocardiographic monitoring, taking into consideration the potential risk of hemodynamic progression. FCT (both multiple and single) can be the first sign of tuberous sclerosis complex in later prenatal or postnatal life. Single FCT other than rhabdomyoma can be asymptomatic in newborns, but may require an early surgical resection, therefore delivery in tertiary centers is recommended. FCT are a good example of the practical value of prenatal cardiology development.

The foramen ovale and the ductus arteriosus are fetal circulation shunt sites, and the appropriate flow profile in these shunts allows the maintenance of fetal hemodynamic stability. The presence of restrictive or closed foramen ovale and/or ductus arteriosus may lead to poor fetal outcomes, such as right ventricular failure, neonatal pulmonary hypertension, or even death. Fetal echocardiography is the main tool for the diagnosis and assessment of premature closure of the foramen ovale and/or ductus arteriosus, and its intrauterine and/or postnatal management. In some cases, fetal intervention or soon after birth may be required in the presence of fetal hemodynamic instability.

The main function of the heart is to provide an adequate perfusion to the different organs. This function is achieved through an adequate filling of the ventricles from the atria (diastole) and the subsequent contraction of the muscular walls in order to generate a sufficient pressure to eject blood from the ventricles into the aorta and pulmonary artery (systole). The inability of the heart to provide sufficient perfusion the body tissues is defined as “heart failure”. In the fetus, heart failure is usually a late event characterized by cardiomegaly, atrioventricular regurgitation and fetal hydrops that occur after a subclinical period of cardiac dysfunction when the heart tries to adapt to the initial stages of an insult through cardiac remodelling. Different cardiac and extra-cardiac conditions can lead to fetal cardiac dysfunction and cardiac failure in utero. Intrinsic cardiac conditions potentially leading to heart failures include cardiomyopathies, structural abnormalities and persistent arrhythmias, while extrinsic causes comprise extra-cardiac lesions that contribute to heart failure through high output states, increased afterload, or cardiac compression resulting in low cardiac output and increased central venous pressures. The aim of this chapter is to provide an up-to-date on the causes, physiopathology, prenatal diagnosis and clinical implications of the most common extra-cardiac conditions potentially leading to fetal heart dysfunction.

Fetal echocardiography began in the late 1970’s with the development of ultrasound imaging and has progressed to be able to make the diagnosis of many forms of structural and functional congenital heart disease. Coupled with the pulsed and color Doppler technique, echocardiography has made advances in determining the prognosis of individual fetuses in utero. The assessment of fetal cardiac function in fetuses continues to evolve including many markers of poor prognosis in the fetus. A tool for this clinical diagnosis is the Cardiovascular Profile Score. This score has become the “heart failure score” and combines echo markers of fetal cardiovascular functional deficits that have been correlated with perinatal mortality. The goal of this score is to detect signs of heart failure before they progress to non-immune-hydrops fetalis. The fetus with hydrops from noncardiac causes may improve spontaneously, or progress to develop heart failure and the score can be used in the early assessment of this fetal clinical picture development. This chapter presents the CVP score for use in fetuses who appear to have heart failure.

Extracardiac malformations (ECMs) and chromosomal abnormalities are common in fetuses with some congenital heart defects (CHD). The frequency and type of ECMs and chromosomal abnormalities vary according to the type of CHD and the studied population. The detection rate of CHD and ECMs depends on the first-trimester screening through nuchal translucence (NT) measurement, second trimester anomaly scan, and fetal echocardiography. The CHDs most frequently associated with ECMs are atrioventricular septal defect (AVSD), ventricular septal defect (VSD), tetralogy of Fallot (TOF), hypoplastic left heart syndrome (HLHS), tricuspid atresia (TA), aortic arch, coarctation of the aorta (CoA) and interruption of the aortic arch (IAA). Conversely, the association of ECMs and chromosomal abnormalities with the transposition of the great arteries (TGA) is low. CHD such as: Ebstein's anomaly, left ventricular outflow tract obstruction (aortic stenosis) and obstruction of the right ventricular outflow tract (atresia and pulmonary stenosis) are associated with extremely low ECMs and chromosomal abnormalities, and are limited to a few sporadic cases.

Congenital defects are frequent, occurring in 2-3% of live births, with high morbidity and mortality. Congenital heart defects are the most frequent, occurring in 1% of all live births. Most occur as isolated malformations, but approximately 1/3 are part of a syndrome, usually of genetic etiology. The correct etiological diagnosis is important for useful clinical follow-up and genetic counseling. Children born with congenital heart defects should be carefully examined for other malformations and dysmorphia.

Congenital heart diseases (CHD) are common, of largely unknown etiology, with high mortality. This chapter presents the available information on environmental factors that may alter the risk for CHD. Information regarding parental characteristics and conditions, maternal therapeutic drug exposures, parental nontherapeutic drug exposures, and environmental exposures are presented. Aside from some cardiac teratogens and prenatal maternal conditions or exposures associated with an increased risk for CHD, such as thalidomide, and retinoids, smoking, maternal rubella infection, phenylketonuria, hypertension, and diabetes, studies investigating most of environmental risk factors have yielded conflicting results. Associations were found for febrile illness, in vitro fertilization, stressful life events, hyperhomocysteinemia, obesity, hypertension, antihypertensives, bronchodilators, anticonvulsant drugs, nontherapeutic drugs, alcohol, air pollution, disinfectant products, pesticides, solvents, metals and landfill/hazardous waste sites. Some principles for prevention can be useful, as preconception and prenatal care with specific attention to the intake of folic acid, vaccination for rubella, detection and effective management of phenylketonuria, hypertension, and diabetes, discussion of any medicine use, avoidance of infections and chemical exposures, alcohol, smoking, and non-therapeutic drugs. Women receiving therapeutic drugs should be regularly monitored. In addition, screening for CHD should be performed when environmental risk factors are present. Further investigations for the development of prevention and intervention are needed.

Congenital heart defects (CHDs) are the most common defects at birth. Thus, their prenatal diagnosis is extremely important, since early intervention, when required, dramatically reduces newborn mortality. CHDs, that occur both at the intrauterine phase and during the first hours of life, are well tolerated and do not require specialized care during delivery. However, some severe CHDs have an increased risk of hemodynamic instability and may require maintenance of fetal shunts after birth. In these cases, planning the time of delivery and selecting a tertiary hospital are necessary. In some cases, there may be maternal or fetal indications to anticipate delivery, including a variety of obstetric ones. Thus, the birth of a newborn with CHD is a multidisciplinary event, involving obstetricians, neonatologists, and cardiologists.

Fetal heart interventions have been developed for select cardiac defects in order to alter the natural history of disease and improve patients´ outcomes. Intervention rationale and patient selection criteria, as well as associated risks and procedural technical considerations have been reviewed. Fetal aortic valvuloplasty is performed in fetuses with severe aortic stenosis with evolving hypoplastic left heart syndrome, with improving rates of biventricular outcome and early survival; and in rare cases of fetuses with aortic stenosis with severe mitral insufficiency and restrictive foramen ovale. Fetal atrial septoplasty with atrial septal stent placement in patients with hypoplastic left heart syndrome with intact or highly restrictive atrial septum has not yet demonstrated a decrease in the disease´s associated mortality. There is limited data regarding the results of fetal pulmonary valvuloplasty in fetuses with pulmonary atresia with intact ventricular septum with evolving hypoplastic right ventricle. Pericardiocentesis for severe pericardial effusion secondary to heart tumors or a cardiac diverticulum or aneurysm continues to be a rare procedure in an exceptional condition. Key aspects regarding selection criteria for intervention and technical and clinical results, require further study in a multicenter collaborative approach.

Management strategies for congenital heart disease (CHD) in the neonate have evolved significantly. Advances in surgical technique, medical technology, and perioperative care have resulted in excellent post-repair survival, even for complex types of CHD. Furthermore, with the increased availability and accuracy of prenatal diagnosis by fetal echocardiography, the postnatal management of these newborns can often be anticipated and planned. The prenatal diagnosis of CHD has been associated with decreased morbidity and mortality for some forms of major CHD. As most cases of major CHD are not identified prenatally, clinical examination of the newborn and pulse oximetry are also important means of identifying additional cases. In summary, to improve the outcomes of a neonate with CHD, surgical repair or catheter intervention may be offered. For this purpose, early recognition of a neonate with CHD is necessary for stabilization and timely intervention.

The advances in neonatal care and pediatric cardiac surgery have allowed repairing of complex congenital heart disease in the newborn and young infants with excellent results. The most common congenital heart defects that may need early surgical treatment are tetralogy of Fallot (TOF), transposition of the great arteries (TGA), univentricular heart, total anomalous pulmonary veins connection, hypoplastic left heart syndrome, critical aortic stenosis, and truncus arteriosus. TGA, characterized by atrioventricular concordance with ventriculoarterial discordance, is the most common cyanogenic cardiopathy, which requires treatment in the neonatal period. Atrioseptostomy with Raskind balloon must be performed in the newborn with TGA, who presents significant hypoxia and restrictive atrial septal defect. Surgical treatment of TGA depends on the gestational age diagnosis, associated defects and evaluation of the left ventricle anatomy and function. TOF is the cyanogenic cardiopathy that requires therapy more frequently within the first year of life. Those newborns with TOF who present severe cyanoses and or hypoxic crises may become ductus dependent, requiring surgical shunting procedure, percutaneous ductal stenting or total repair. Currently, there is a trend to perform neonatal total surgical repair in the centers of excellence, based in the low surgical risk. In univentricular hearts, medical decision depends on some anatomical aspects. While in case of significant pulmonary flow obstruction, it will require shunting procedure, in case of pulmonary overflow, it may need pulmonary banding. Total anomalous pulmonary venous return, critical aortic valve stenosis, and pulmonary atresia patients will require surgical or interventional heart catheterization procedures as a newborn. While, newborns with Ebstein’s anomaly have about 60% chance of requiring early surgical intervention.