Congenital heart defects: natural course and in utero development

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.

Detailed transabdominal fetal anatomic scanning in the late first trimester versus the early second trimester of pregnancy

OBJECTIVES

To compare visualization rates for early targeted organ scanning at gestational ages ranging from 11 weeks 3 days to 13 weeks 2 days versus 14 weeks 3 days to 16 weeks 2 days.

METHODS

We conducted a prospective longitudinal study of patients who presented for nuchal translucency (NT) screening and targeted organ scanning. Extended targeted organ scanning, including the central nervous system, face and neck, chest, heart (including complete echocardiography), digestive system, abdominal wall, urinary system, skeleton, and umbilical cord with its insertion and placenta, was performed on gravidas in 2 age ranges. Uterine artery Doppler mapping was performed during the second scan. All cases were examined twice: once at NT screening (up to 13 weeks 2 days) and again in the early second trimester.

RESULTS

A total of 408 women were recruited and scanned twice. Three abnormalities were diagnosed in the second scan that were not seen in the first: dysplastic long bones, tricuspid stenosis, and cleft lip (without palate involvement). None had chromosomal anomalies. Successful visualization rates in all organ systems exceeded 94% in the second trimester. At the first-trimester scan, some systems had high success rates, whereas others were very low; eg, in the brain, the cerebellum and posterior fossa were visualized successfully approximately 50% of the time and the upper lip only approximately 10%. On fetal echocardiography, the 4-chamber view and outflow tracts were imaged successfully approximately 40% of the time, and the kidneys approximately 35%. Uterine artery Doppler mapping was possible in all patients on at least one side. On third-trimester follow-up, we diagnosed 1 mild pulmonary stenosis, 1 autosomal recessive polycystic kidney disease, and 1 ventricular septal defect.

CONCLUSIONS

The early second-trimester scan was much more productive than targeted organ scanning performed during the NT window. When counseling women regarding the optimal time for early transabdominal targeted organ scanning, successful visualization rates for various organ systems should be considered.

First-trimester fetal cardiac examination using spatiotemporal image correlation, tomographic ultrasound and color Doppler imaging for the diagnosis of complex congenital heart disease in high-risk patients

OBJECTIVE

A four-dimensional (4D) fetal echocardiographic technique utilizing spatiotemporal image correlation, tomographic ultrasound imaging display (STIC-TUI echo) and color Doppler has previously been shown to be effective in displaying the examination planes constituting the extended cardiac examination. The aim of this study was to evaluate the performance of this first-trimester STIC-TUI echo technique in identifying complex congenital heart disease (CHD) in high-risk pregnancies.

METHODS

This was a prospective study of patients presenting at first-trimester screening who were at high risk for CHD owing to pregestational diabetes, in-vitro fertilization (IVF), increased nuchal translucency (NT) thickness, first-trimester tricuspid regurgitation or reversed ductus venosus (DV) a-wave, a previous child with CHD or who were on anticonvulsant medication. First-trimester STIC-TUI echo was performed, and the findings were correlated with second-trimester echocardiography and post-delivery echo findings in survivors.

RESULTS

One hundred and sixty-four fetuses from 152 patients were enrolled (77 diabetics, 38 IVF, 14 with increased NT, 23 cases of tricuspid regurgitation or reversed a-wave in the DV, 22 with prior CHD and two on anticonvulsants). STIC-TUI echo was abnormal in 20 (12%), showing atrioventricular canal defect (n = 9), hypoplastic left heart (n = 2), pulmonary stenosis (n = 2), right aortic arch (n = 1), interrupted aortic arch (n = 1), tricuspid atresia (n = 1), heterotaxy (n = 1), persistent truncus arteriosus (n = 1), double outlet right ventricle and ventricular septal defect (n = 1) and double inlet ventricle with transposition of the great arteries (n = 1). 85% of these anomalies were evident in the four-chamber view plane of the TUI display, and the remainder were diagnosed in the outflow tract planes with color Doppler imaging. In 13, CHD was isolated while seven had extracardiac anomalies. Thirteen fetuses had aneuploidy and all 13 underwent first-trimester termination of pregnancy. In the remaining seven, second-trimester echocardiography and neonatal echo/postmortem examination confirmed anomalies (two stillborn neonates, one neonatal death, four live births). Two cases of CHD missed by first-trimester STIC-TUI echo were diagnosed on second-trimester echo. Accordingly, first-trimester STIC-TUI echo had 91% sensitivity and 100% specificity for the detection of CHD.

CONCLUSIONS

First-trimester 4D echocardiography using a standardized application of STIC, TUI and color Doppler imaging is effective in displaying the imaging planes that are necessary for achieving the diagnosis of complex cardiac anomalies in high-risk patients. Optimal imaging of the four-chamber view with two-dimensional ultrasound is the major determinant of successful volume acquisition.

Imaging the first trimester heart: ultrasound correlation with morphology

First trimester sonography is a widely used technique to examine the foetus early in pregnancy. The desire to recognise complex anatomy already in early developmental stages stresses the need for a thorough knowledge of basic developmental processes as well as recognition of cardiac compartments based on their morphology. In this paper, we describe the possibilities and limitations of sonographic assessment of the foetal heart between 10 and 14 weeks of gestation and correlate this to morphology. Examples of the most commonly detected congenital anomalies are atrioventricular septal defects, transposition of the great arteries, and hypoplastic left heart, which are shown in this paper.

Prenatal Isolated Ventricular Septal Defect May Not Be Associated with Trisomy 21

The aim of this study was to examine if isolated fetal ventricular septal defect (VSD) is associated with trisomy 21. One hundred twenty six cases with prenatal VSD diagnosed by a pediatric cardiologist were reviewed. Cases with known risk factors for congenital heart disease, the presence of other major anomalies, soft signs for trisomy 21 or a positive screen test for trisomy 21 were excluded. Ninety two cases formed the study group. None of the cases in the study group had trisomy 21. The upper limit of prevalence for trisomy 21 in isolated VSD is 3%. When prenatal VSD is not associated with other major anomalies, soft markers for trisomy 21 or a positive nuchal translucency or biochemical screen, a decision whether to perform genetic amniocentesis should be individualized. The currently unknown association between isolated VSD and microdeletions and microduplications should be considered when discussing this option.

Comparison of echocardiographic findings in fetuses at less than 15 weeks' gestation with later cardiac evaluation

OBJECTIVE

To compare the echocardiographic findings in fetuses at < 15 weeks' gestation with a later follow-up scan, and determine both the accuracy of early diagnosis and the frequency of findings that change between scans.

METHODS

For the period 2002 to the end of 2009, we searched our database for all patients who had had a detailed fetal echocardiogram at less than 15 completed weeks' gestation and a repeat scan at least 6 weeks later.

RESULTS

Of 1200 patients fulfilling our selection criteria, the cardiac findings were normal at both scans in 1069. In 46 cases the same cardiac abnormality was seen at both scans. There was a false-positive diagnosis at early scan in seven cases. In 50 cases, there were mildly abnormal functional findings early in pregnancy with no abnormality found later. In 29 fetuses, there was discordance between the early and later morphological diagnosis, 15/29 being considered significant differences, with 10/15 representing true progression of findings between the early and later scans, rather than missed or incorrect diagnoses.

CONCLUSIONS

A high degree of accuracy in the identification of congenital heart disease can be achieved by early fetal echocardiography (sensitivity 84.8 (95% CI, 75.0-91.9)%, specificity 95.3 (95% CI, 93.9-96.4)%), although the identification of every case of tetralogy of Fallot and small atrioventricular septal defects presents particular diagnostic challenges at this gestational age. A small but significant group showed progression of findings during this stage of rapid fetal heart growth, particularly in obstructive lesions.

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.

Echocardiography in Early Pregnancy

Within the last decade, two significant events have contributed to the increasing interest in early fetal echocardiography. First, the introduction of high frequency vaginal ultrasound probes allows detailed visualization of cardiac structures at early stage of gestation, making early detection of fetal malformations possible. Second, the close relationship observed between some first trimester sonographic and Doppler markers and congenital heart defects allows an early identification of a high-risk group at 11 to 14 weeks of gestation. In this context, from the early 1990s, many authors have examined the potential role of the transvaginal approach to obtain earlier diagnosis of fetal cardiac malformations. Further studies have appeared in the literature showing that early transvaginal echocardiography in experienced hand is a fairly sensitive investigative tool. Although some malformations are detected as early as 11 weeks’ gestation, the optimal gestational age to perform the early scan is at least 13 weeks’ gestation. Transvaginal ultrasound is the preferred approach, although most of the authors agree that results can be improved if transabdominal ultrasound is also incorporated. The further application of color Doppler enhances visualization. The sensitivity and specificity of early fetal echocardiography for the detection of heart anomalies is acceptable compared to the ones obtained by mid-gestational echocardiography, showing a slight reduction in detection rates and an increase in false positive and negative rates. The cardiac anomalies detected at this early stage of pregnancy are mainly defects involving the four-chamber view, indicating that defects solely affecting the outflow tracts are difficult to diagnose in the first trimester of pregnancy. Heart defects diagnosed early in pregnancy tend to be more complex than those detected later, with a higher incidence of associated structural malformations, chromosomal abnormalities and spontaneous abortions. The neonate follow-up or postmortem examination in case of termination of pregnancy (TOP) is essential to assess the actual role of early fetal echocardiography. At present, early fetal echocardiography is a promising technique, which can be of considerable value for patients at high-risk. This technique is, however, currently limited to a few specialized centers.

The aim of this review is to explore the possibilities of examining the fetal heart at this early stage of pregnancy. This article also present our experience in the first multicenter trial in early fetal echocardiography performed in Spain. In accordance with other studies, this experience stresses the usefulness of early echocardiography when performed by expert operators on fetus specifically at risk for cardiac defects. Our review of these additional 48 cases contributes to the expanding literature on the ability of transvaginal ultrasonography to detect fetal heart defects in early pregnancy.

How to cite this article

Gabriel CC, Rodriguez PP. Echocardiography in Early Pregnancy. Donald School J Ultrasound Obstet Gynecol 2013;7(2):168-181.

Comparison of real-time three-dimensional echocardiography and spatiotemporal image correlation in assessment of fetal interventricular septum

OBJECTIVE

To compare the role of real-time 3DE and STIC technology in assessment of the fetal IVS.

METHODS

Fifty pregnant women with singleton pregnancies were invited to attend this study. All the fetuses were examined by both spatiotemporal image correlation and real-time three-dimensional echocardiography. There were totally six images of IVS obtained for each fetus: live xPlane image, live 3D image, multiplanar image and rendered image with the four-chamber view as the starting plane, multiplanar image and rendered image with the sagittal view of the fetal thorax as the starting plane. These images were grouped into six groups and randomized within each group for the further analysis. The images were scored and compared according to the image quality, the outline of the fetal IVS and motion artefact. The operator was also asked to judge whether VSD existed or not and the results were compared with the final diagnosis. The sensitivity, specificity, false positive percentage, positive likelihood ratio, false negative percentage and negative likelihood ratio of each group were also calculated.

RESULTS

There were 15 cases with VSD and four cases without VSD in CHD fetus and 31 cases of normal fetus enrolled in this study. A total 300 images of the lateral view of fetal IVS were obtained and grouped into six groups. The image quality in the group of STIC with the four-chamber view as the starting plane is much worse than the group of STIC with the sagittal view as the starting plane and real-time three-dimensional echocardiography (P < 0.05). There were no significant differences in image quality between the group of STIC with the sagittal view as the starting plane and real-time three-dimensional echocardiography (P > 0.05).

CONCLUSION

The image quality of real-time 3DE is similar to the images acquired by STIC from the sagittal view and superior to that obtained by STIC from the four-chamber view. However, real-time 3DE has no motion artefact, which has the potentials to improve the detection rate of fetal VSD.

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.

Congenital cardiac anomalies: prenatal readings versus neonatal outcomes

OBJECTIVE

The purpose of this study was to determine the variation between prenatal and postnatal diagnosis of congenital cardiac lesions diagnosed by both fetal center primary physicians and fetal pediatric cardiologists at a single tertiary referral center in the United States and evaluate why cases were misdiagnosed.

METHODS

A retrospective review of all cardiac abnormalities identified prenatally by level II sonography at a tertiary referral fetal center between January 2006 and December 2008 was performed to include any patient with a fetal cardiac abnormality and with a documented autopsy or neonatal follow-up. Congenital heart disease diagnoses were classified as correct, incorrect, or incorrect but within the same spectrum of disease. Cases of correct diagnosis by primary physicians and pediatric cardiologists were compared.

RESULTS

Sixty patients with fetal heart abnormalities were identified among 8894 patients who had level II sonography. The combined detection rate for fetal heart abnormalities for both primary physicians and pediatric cardiologists together was 81.7%. The detection rates of congenital heart disease were not statistically different between primary physicians and pediatric cardiologists: 77.9% (46 of 59) versus 85.0% (34 of 40; P = .3). The most common cardiac abnormalities misdiagnosed in our study population included pulmonic stenosis, ventricular septal defect, myxoma, truncus arteriosus, and coarctation of the aorta.

CONCLUSIONS

Congenital heart disease is misdiagnosed in tertiary care centers by both pediatric cardiologists and fetal imaging specialists. We believe that this occurrence is related to multiple factors, including evolution of congenital heart disease, maternal body habitus, associated congenital anomalies, decreased amniotic fluid volume, gestational age at evaluation, imaging techniques, and, most importantly, the experience of the sonographer.

Results of early foetal echocardiography and cumulative detection rate of congenital heart disease

OBJECTIVE

The aim of this study is to evaluate the cumulative detection rate of foetal echocardiography during gestation and in the early neonatal period, with a special emphasis on early foetal echocardiography.

METHODS

We conducted a retrospective survey of all singleton pregnancies from 1993 to 2007, with complete sequential echocardiography from 11 plus 0 to 13 plus 6 weeks of gestation. It was mandatory to have at least one foetal echocardiography in the second or third trimester and one postnatally.

RESULTS

Our study included 3521 pregnancies, in which 77 cases were diagnosed with congenital heart disease. Of them, 66 were detected in the first trimester - 11 plus 0 to 11 plus 6 weeks: 22 cases; 12 plus 0 to 12 plus 6 weeks: 23 cases; 13 plus 0 to 13 plus 6 weeks: 21 cases - with an 85.7% detection rate of congenital heart disease in early foetal echocardiography. In the second trimester, seven cases were found, with a detection rate of 9.1%. The third trimester reported two cases, with a detection rate of 2.6%. Postnatally, two (2.6%) cases were detected. The overall in utero detection rate of congenital heart disease was 97.4%.

CONCLUSIONS

Foetal echocardiography performed at the time of anomaly screening in the first trimester results in high detection rates of congenital heart disease. Cardiac pathology may evolve, and further examinations at later stages of pregnancy could improve the detection rate of congenital heart disease.

Fetal heart ventricular mass obtained by STIC acquisition combined with inversion mode and VOCAL

OBJECTIVE

Estimation of fetal heart ventricular mass is important for fetal cardiac evaluation in cases of structural or functional cardiac disorders or extracardiac factors. It may be used with other cardiac parameters to ascertain the severity and prognosis of such disorders, or the nature and timing of intervention. We applied a novel technique combining spatiotemporal image correlation (STIC) with three-dimensional inversion mode and Virtual Organ Computer-aided AnaLysis (VOCAL™) for fetal cardiac mass assessment in healthy fetuses in the second and third trimesters.

METHODS

STIC acquisition was performed during fetal quiescence with the abdomen uppermost, at an angle of 30-50°, without color Doppler mapping. Myocardial volume measurements were performed in postprocessing using VOCAL mode, set to 15°. Beginning with the heart in four-chamber view at end diastole, a trace was drawn manually including the myocardium and interventricular septum. Inversion mode colors the intraventricular (anechoic, fluid-filled) voxels; this intraventricular volume was subtracted automatically from the total. Mass was determined by multiplying the result by the estimated fetal myocardial density (1.050 g/cm(3) ). The process was repeated for right and left ventricles.

RESULTS

Data from 106 fetuses at 21-38 weeks' gestation were obtained and scatterplots of fetal cardiac ventricular mass distribution were created. Several cases of fetuses with disordered cardiac ventricle (supraventricular tachycardia, hypoplastic left heart syndrome, dilated cardiomyopathy, twin-to-twin transfusion syndrome, Ebstein anomaly, non-immune hydrops fetalis, septate right atrium and diaphragmatic hernia) were examined. Ventricular mass parameters were markedly affected as compared with normal cases of similar gestational age.

CONCLUSIONS

STIC acquisition combined with inversion mode and VOCAL is a feasible method of cardiac ventricular mass quantification. This methodology may have added value in fetal cardiac evaluation in cases of anatomic malformation or cardiac dysfunction, or in cases of maternal diabetes.

Added value of three-/four-dimensional ultrasound in offline analysis and diagnosis of congenital heart disease

OBJECTIVE

Many published studies have shown that application of three-dimensional (3D) and real-time 3D (4D) ultrasound modalities can improve certain aspects of fetal echocardiography, but have left open the question of whether these modalities improved the accuracy of prenatal detection of anatomical fetal cardiovascular malformations. We aimed to determine whether 3D/4D ultrasound improved diagnostic ability in cases of congenital heart disease (CHD).

METHODS

Women who attended for early- or midtrimester targeted organ scans had complete fetal echocardiography according to our five-planes protocol, as well as examination of the ductus venosus and longitudinal aortic arch planes, performed with 2D ultrasound combined with 2D color Doppler, spatiotemporal image correlation (STIC), STIC with color Doppler, and STIC with B-flow. Ultrasound data of cases of CHD were stored in a dedicated archive. Stored cases were anonymized and the list order was randomized. Stored 2D ultrasound cineloops and 4D ultrasound volumes were reviewed separately according to a standardized table of 23 specified structures on five required planes of visualization: the upper abdomen, four-chamber view, five-chamber view, pulmonary artery bifurcation view, and three vessels and trachea plane. Separate diagnoses were recorded and finally compared. Diagnoses were confirmed by pathological examination or neonatal echocardiography.

RESULTS

During the study period, 13 101 examinations were performed; 181 diagnoses of CHD were made. In 12 of these, 3D/4D ultrasound added to the accuracy of our diagnosis: one right aortic arch with anomalous branching; one transposition of the great arteries with pulmonary atresia diagnosed with tomographic ultrasound imaging (TUI); one segmental interrupted aortic arch diagnosed with TUI; one right ventricle aneurysm diagnosed with B-flow; two agenesis of ductus venosus to the coronary sinus diagnosed by multiplanar reconstruction (MPR) and B-flow; two total anomalous pulmonary venous connection diagnosed with MPR; and four ventricular septal defect (VSD) diagnosed with the aid of virtual planes. There were 12 missed diagnoses and no false-positive results.

CONCLUSIONS

3D/4D ultrasound modalities may have advantages in some aspects of fetal cardiovascular evaluation, however, overall 3D/4D ultrasound modalities had added value in only about 6% of cases of fetal anatomical cardiovascular anomalies.

Prenatal double aortic arch presenting with a right aortic arch and an anomalous artery arising from the ascending aorta

Double aortic arch is a rare anomaly of the aortic arch and this may cause tracheal damage by compressing the trachea during the first year of life. We report here on three fetal cases of double aortic arch and their outcomes. These malformations presented as an isolated right aortic arch or as a typical vascular ring form on the prenatal echocardiography that was obtained between 22 and 24 weeks gestation. In two of the three patients, the major intracardiac anomaly was a ventricular septal defect, and this was associated with the aortic malformation. A more detailed evaluation of the branching pattern of the aorta, and particularly whether the aorta gives off a left-sided limb of the double arch, could suggest the diagnosis of a double aortic arch in utero. Two patients underwent successful surgical correction and they showed good clinical outcomes. Fetal double aortic arch can be prenatally suspected after performing fetal echocardiography for those fetuses that show a right side aortic arch, and this can help to avoid delaying the postnatal management of this rare anomaly.

Real-time three-dimensional echocardiography using a matrix probe with live xPlane imaging of the interventricular septum

OBJECTIVE

To describe a technique to rapidly visualize the in-plane view of the fetal interventricular septum (IVS) to enable the identification of a ventricular septal defect (VSD).

METHODS

One hundred and fifty-one women were invited to participate after their routine fetal morphology scan, including four suspected to have congenital cardiac defects which were confirmed postnatally. A standard examination protocol using real-time three-dimensional (3D) echocardiography with live xPlane imaging was developed. The ability of this new technology to examine the ventricular septum was investigated.

RESULTS

The in-plane view of the fetal IVS was visualized successfully in 150 (99.3%) cases by real-time 3D echocardiography with live xPlane imaging, including 82 (54.3%) cases with the spine posterior and 68 (45.7%) cases with the spine anterior. The in-plane view of the IVS successfully visualized the VSDs in three fetuses with VSD and displayed the intact IVS in one fetus with transposition of the great arteries without VSD.

CONCLUSION

We describe live xPlane imaging, a simple method for the real-time assessment of the in-plane view of the IVS that has the potential to enhance the diagnostic accuracy of fetal cardiac examination.

The nuchal translucency and the fetal heart: a literature review

In this overview the current knowledge of the relationship between an increased nuchal translucency (NT) measurement and fetal heart structure and function in chromosomally normal fetuses is reviewed. Relevant pathophysiological theories behind the increased NT are discussed. Fetuses with an increased NT have an increased risk for congenital heart disease (CHD) with no particular bias for one form of CHD over another. This risk increases with increasing NT measurement. Although the NT measurement is only a modestly effective screening tool for all CHD when used alone, it may indeed be effective in identifying specific CHD "likely to benefit" from prenatal diagnosis. The combination of an increased NT, tricuspid regurgitation and an abnormal ductus venosus (DV) Doppler flow profile, is a strong marker for CHD. A fetal echocardiogram should be performed at 20 weeks' gestation in fetuses with an NT > or = 95th percentile but < 99th percentile. When the NT measurement is > or = 99th percentile, or when tricuspid regurgitation and/or an abnormal DV flow pattern is found along with the increased NT, an earlier echocardiogram is indicated, followed by a repeat scan at around 20 weeks' gestation. The resultant increased demand for early fetal echocardiography and sonographers with this special expertise needs to be planned and provided for.

Hypoplastic left heart syndrome

Hypoplastic left heart syndrome is a rare congenital heart defect in which the left side of the heart is underdeveloped. Surgical management of hypoplastic left heart syndrome has changed the prognosis of the condition that was previously regarded as fatal. We discuss surgical strategies based on staged procedures, with the right ventricle supporting both systemic and pulmonary circulation. We also discuss other management options, such as neonatal transplantation and the recent innovation of hybrid techniques. Surgical techniques and the understanding of the pathophysiology of this condition have been at the forefront of neonatal cardiac surgery and intensive care. The management of the syndrome remains a challenge because affected children grow into adolescence and adulthood posing various new problems and demands.

Quality of 2- and 3-dimensional fast acquisition fetal cardiac imaging at 18 to 22 weeks: ramifications for screening

OBJECTIVE

The purpose of this study was to evaluate the frequency with which 6 different fetal cardiac views taken during a fetal ultrasound examination at 18 to 22 weeks' gestation can be obtained satisfactorily for cardiac anomaly screening using either a 2-dimensional (2D) static or 3-dimensional (3D) fast acquisition technique.

METHODS

A prospective study of 100 low-risk women undergoing an anatomic survey was performed. Standard static 2D and 3D fast acquisition volumes were obtained on all patients. The 2D and 3D images were assigned, in a random order, to be independently graded by 3 reviewers. The degree of inter-reviewer agreement was assessed through the use of the Cohen kappa statistic. The factors contributing to satisfactory imaging were evaluated by random effects logistic regression.

RESULTS

A significant proportion of both 2D and 3D images were judged unsatisfactory for screening purposes. However, 2D images were significantly more likely, for all cardiac views, to be judged satisfactory (P < .05). The odds ratios for the 2D technique's being more likely than the 3D technique to provide images satisfactory for screening were 2.6 for the 4-chamber view, 2.4 for the right ventricular outflow tract, 4 for the left ventricular outflow tract, 3.2 for the 3-vessel view, 8.6 for the aortic arch, and 2.2 for the ductal arch.

CONCLUSIONS

In this prospective study, static 2D imaging was significantly more likely than fast acquisition 2D imaging to yield cardiac views of high enough quality to satisfactorily screen for anomalies.

Prenatal diagnosis and treatment planning of congenital heart defects-possibilities and limits

BACKGROUND

Newborns with hypoplastic left heart syndrome (HLHS) or right heart syndrome or other malformations with a single ventricle physiology and associated hypoplasia of the great arteries continue to be a challenge in terms of survival. The vast majority of these forms of congenital heart defects relate to abnormal morphogenesis during early intrauterine development and can be diagnosed accurately by fetal echocardiography. Early knowledge of these conditions not only permits a better understanding of the progression of these malformations but encourages some researchers to explore new minimally invasive therapeutic options with a view to early pre- and postnatal cardiac palliation.

DATA SOURCES

PubMed database was searched with terms of "congenital heart defects", "fetal echocardiography" and "neonatal cardiac surgery".

RESULTS

At present, early prenatal detection has been applied for monitoring pregnancy to avoid intrauterine cardiac decompensation. In principle, the majority of congenital heart defects can be diagnosed by prenatal echocardiography and the detection rate is 85%-95% at tertiary perinatal centers. The majority, particularly of complex congenital lesions, show a steadily progressive course including subsequent secondary phenomena such as arrhythmias or myocardial insufficiency. So prenatal treatment of an abnormal fetus is an area of perinatal medicine that is undergoing a very dynamic development. Early postnatal treatment is established for some time, and prenatal intervention or palliation is at its best experimental stage in individual cases.

CONCLUSION

The upcoming expansion of fetal cardiac intervention to ameliorate critically progressive fetal lesions intensifies the need to address issues about the adequacy of technological assessment and patient selection as well as the morbidity of those who undergo these procedures.

Is fetal anatomic assessment on follow-up antepartum sonograms clinically useful?

OBJECTIVE

The purpose of this study was to evaluate the clinical usefulness of a fetal anatomic survey on follow-up antepartum sonograms.

METHODS

A retrospective follow-up study was conducted at a low-risk maternity clinic from July 1, 2005, to June 30, 2006. Eligible women had at least 1 prior sonographic examination beyond 18 weeks' gestation with a complete and normal fetal anatomic assessment and at least 1 follow-up sonogram. Full fetal anatomic surveys were performed on all follow-up sonograms regardless of the indication. Neonatal charts were reviewed for those patients whose follow-up sonograms revealed unanticipated fetal anomalies. Neonatal intervention was defined as surgical or medical therapy or arranged subspecialty follow-up specifically for the suspected fetal anomaly.

RESULTS

Of a total of 4269 sonographic examinations performed, 437 (10.2%) were follow-up studies. Of these, 101 (23.1%) were excluded because the initial sonogram revealed a suspected fetal anomaly, and 42 (9.8%) were excluded for other reasons. Of the remaining 294 women, 21 (7.1%) had an unanticipated fetal anomaly, most often renal pyelectasis. Compared with follow-up sonography for other reasons, repeated sonography for fetal growth evaluation yielded a higher incidence of unexpected fetal anomalies: 15 (12.3%) of 122 versus 6 (3.5%) of 172 (P = .01). When compared with the neonates in the nongrowth indications group, those neonates whose mothers had sonographic examinations for fetal growth had a higher rate of neonatal interventions: 6 (40.0%) of 15 versus 0 (0%) of 6 (P = .04).

CONCLUSIONS

A fetal anatomic survey on follow-up sonograms may identify unanticipated fetal anomalies, especially when the indication is for fetal growth.

First and early second trimester fetal heart screening

PURPOSE OF REVIEW

This review describes the recent advances in timing and effectiveness of first and early second trimester fetal echocardiography screening.

RECENT FINDINGS

Fetal echocardiography can now be reliably performed from 11 weeks' gestation owing to improvements in ultrasound transducers and processors. Three-dimensional and four-dimensional ultrasound modalities in image acquisition and postprocessing analysis, including spatio-temporal image correlation, rendering three-dimensional power Doppler and high definition power flow Doppler, and B-flow have further improved our capabilities in this area. Fetal nuchal translucency measurement screening programs create a new population of at-risk pregnancies that will be referred for early fetal echocardiography. The majority of congenital heart defects, however, still occur in low-risk patients. Improved technology has lowered the gestational age at which fetal cardiac anatomy scanning can be reliably performed by properly trained and experienced examiners.

SUMMARY

Early fetal echocardiography can be offered as a screening examination to at-risk and low-risk patients, with the proviso that it be repeated following screen-negative scans at mid-gestation to exclude later developing lesions.

The impact of prenatal diagnosis of congenital heart disease on pediatric cardiology and cardiac surgery

Since the early 1980s prenatal diagnosis of congenital heart disease (CHD) has progressively impacted on the practice of pediatric cardiology and cardiac surgery. Fetal cardiology today raises special needs in screening programs, training of the involved staff, and allocations of services. Due to the increased detection rate and to the substantial number of terminations, the reduced incidence of CHD at birth can affect the workload of centers of pediatric cardiology and surgery. In utero transportation and competition among centers may change the area of referral in favor of the best centers. Echocardiography is a powerful means to diagnose and to guide lifesaving medical treatment of sustained tachyarrhythmias in the fetus. Prenatal diagnosis not only improves the preoperative conditions in most cases but also postoperative morbidity and mortality in selected types of CHD. Intrauterine transcatheter valvuloplasty in severe outflow obstructive lesions has been disappointing so far and this technique remains investigational, until its benefits are determined by controlled trials. Prenatal diagnosis allows counselling of families which are better prepared for the foreseeable management and outcome of the fetus. These benefits can reduce the risks of litigation for missed ultrasound diagnosis. As increased costs can be expected in institutions dealing with a large number of fetal CHD, the administrators of these institutions should receive protected funds, proportional to their needs.

Three-vessel view of the fetal heart: In utero development of the great vessels

OBJECTIVES

The purpose of our study is to provide reference values for the great vessels obtained from images of the three-vessel view of the fetal heart, with an emphasis on the size discrepancy of the great vessels.

METHODS

From February 2003 to May 2003, the main pulmonary artery (MPA), ascending aorta (AA), and SVC were measured in well-dated, nonanomalous fetuses scanned at 14-38 weeks of gestation.

RESULTS

The size of each great vessel had a significant positive relationship with advance in gestation (P < 0.001); MPA (mm) = -2.76 + 0.34 x GA, ascending aorta (AA) (mm) = -1.73 + 0.26 x GA - 1.18E - 05 x GA(3), and SVC (mm) = 0.33 + 0.01 x GA(2) - 4.12E - 05 x GA(3). The AA/MPA ratio was significantly decreased with advance in gestation, while the SVC/AA ratio was significantly increased; AA/MPA ratio = -1.24 - 0.03 x GA + 3.88E - 04 x GA(2); P < 0.001, SVC/AA ratio = 0.63 - 5.43E - 03 x GA + 1.96E - 04 x GA(2); P < 0.001.

CONCLUSION

On the three-vessel view of the fetal heart, the interpretation of the size discrepancy of the great vessels needs to be adjusted according to fetal growth.

Rendering in fetal cardiac scanning: the intracardiac septa and the coronal atrioventricular valve planes

OBJECTIVE

In this study we aimed to apply spatio-temporal image correlation (STIC) rendering to visualize the virtual planes of the interventricular and interatrial septa (IVS, IAS) as well as the atrioventricular (AV) annuli plane just distal to the semilunar valves (coronal atrioventricular (CAV) plane) in normal and pathological fetal hearts, to ascertain whether these planes add to fetal cardiac examination.

METHODS

Unselected gravidae presenting for anatomy scan or patients referred for fetal echocardiography in the second and third trimesters of pregnancy with suspected or diagnosed cardiac malformation were scanned using the five planes technique with the STIC modality to obtain cardiac volume sets for each patient. Rendering capabilities were employed to obtain the 'virtual planes' to evaluate the IVS, IAS, AV annuli, and size and alignment of the great vessels.

RESULTS

A total of 136 normal scans were performed to establish a learning curve for STIC acquisition and post-processing rendering and analysis. An additional 35 cases with cardiac anomalies were accrued. In 131/136 (96.3%) normal scans the IAS and IVS were visualized successfully, while in 127/136 (93.4%) normal fetuses the CAV plane was successfully visualized. In 13 anomalous cases the IVS plane improved ventricular septal defect (VSD) evaluation, and in four the IAS plane contributed to foramen ovale evaluation. The modality improved visualization of the septa and the assessment of the defects, as well as the foramen ovale flap and pattern of movement of the foramen ovale. In five cases the CAV plane improved evaluation of the alignment of the major vessels in relation to the AV annuli, and in three the evaluation of the semilunar valves, with or without malalignment of the great vessels.

CONCLUSIONS

Rendering STIC technology allows the visualization of virtual planes (IAS, IVS, AV annuli-CAV plane), which can clarify our understanding of anatomical defects and may improve communication with the management team and family.

Development of hypoplastic left heart syndrome after diagnosis of aortic stenosis in the first trimester by early echocardiography

We describe a case of aortic stenosis in the first trimester that progressed to hypoplastic left heart syndrome. At 11 + 3 weeks' gestation the four-chamber view was normal but evidence of increased aortic blood velocity prompted the diagnosis of aortic outflow obstruction. At 16 + 6 weeks' gestation the left ventricle was hyperechogenic, globular and dysfunctional, suggesting the development of hypoplastic left heart syndrome. The aortic valve was small and there was no flow across the mitral or aortic valves. From 17 + 3 weeks increased reversed flow in the pulmonary veins suggested restriction of the foramen ovale. Follow-up echocardiographic examinations were performed every 2-3 weeks until delivery at term. Postnatal intervention included a Norwood I operation performed on the 5th postnatal day. We have shown the feasibility and utility of early fetal echocardiography and that a left heart obstruction diagnosed in the first trimester can progress to left heart hypoplasia during the early second trimester. This information is important for planning prenatal and perinatal management.

Prenatal detection of heart defects in a non-selected population of 30,149 fetuses--detection rates and outcome

OBJECTIVES

To evaluate the detection rate of congenital heart defects (CHD) in a non-selected population and to follow outcome after diagnosis.

METHODS

All 30,149 fetuses/newborns that were scheduled to deliver at our hospital between February 1991 and December 2001 were registered prospectively. Of these, 29,460 (98%) fetuses had a prenatal ultrasound scan at our center. The routine fetal examination at approximately 18 weeks' gestation included the four-chamber view and the great arteries of the fetal heart. The follow-up period was 2-13 years.

RESULTS

Of 97 major CHDs, 55 (57%) were detected prenatally, 16% (9/55) prior to, 66% (36/55) at and 18% (10/55) after the routine scan. Forty-four percent (19/43) of the isolated CHDs, 67% (36/54) of those with associated malformations and 48% (11/23) of the isolated ductal-dependent CHDs were detected. Thirty-eight percent (37/97) had an abnormal karyotype. Of the 55 major CHDs detected, 44% (24) of the pregnancies with lethal/serious fetal malformations were terminated, 15% (8) died in utero, 42% (23) were born alive and 27% (15) were still alive after 2 years. Of the 42 CHDs detected postnatally, 2% (1) were terminated for other reasons, 98% (41) were born alive and 81% (34) were still alive after 2 years.

CONCLUSIONS

Prenatal detection of CHD is still a challenge, with a 57% detection rate only. Isolated defects are detected less frequently. The overall outcome suggests that the most severe defects are detected with the present screening setting; only 27% of the babies with major CHDs detected were still alive after 2 years. Data from long-term follow-up will be of importance for the counseling process.

Detection rate of early fetal echocardiography and in utero development of congenital heart defects

OBJECTIVE

The purpose of this study was to evaluate the detection rate of early fetal echocardiography and the in utero development of congenital heart defects (CHD).

METHODS

Cases were selected from all singleton pregnancies between 1997 and 2003 in which detailed fetal 2-dimensional and color-coded Doppler echocardiography was performed in our prenatal unit between 11 weeks' and 13 weeks 6 days' gestation; 2165 cases with complete outcome parameters were analyzed.

RESULTS

During this study period, CHD were diagnosed in 46 fetuses. Between 11 and 13 weeks' gestation, 29 CHD were diagnosed (11 weeks, 9 cases; 12 weeks, 8 cases; and 13 weeks, 12 cases); 9 CHD were found in the second trimester and 2 in the third trimester. The in utero detection rate of fetal echocardiography was 86.96% (n = 40). Six additional CHD (13.04%) were detected postnatally. The spectrum of detected CHD changed with advancing gestational age and was different from the postnatal detected heart defects.

CONCLUSIONS

Early fetal echocardiography is feasible and allows the detection of most CHD. Congenital heart defects vary in appearance at different stages of pregnancy and may evolve in utero with advancing gestational age. Therefore, early fetal echocardiography should always be followed by echocardiography at mid gestation.

Early fetal echocardiography: heart biometry and visualization of cardiac structures between 10 and 15 weeks' gestation

OBJECTIVE

The purpose of this prospective cross-sectional study was to compile normative data about biometry of the fetal heart and great vessels between 10 and 15 weeks in 123 normal singleton pregnancies. Additionally, we investigated the different methods and the optimal examination time of early fetal echocardiography.

METHODS

The interrogated parameters included total heart diameter; heart area and circumference; right and left ventricular diameter; diameter, circumference, and area of the thorax; and diameter of the aorta and pulmonary trunk. Visualization of the 4-chamber view, 3-vessel view, origin and crossover of the great arteries, aortic arch, ductus arteriosus, superior and inferior venae cavae, and pulmonary veins was analyzed, and the success rates by transvaginal sonography (TVS) and transabdominal sonography (TAS) were calculated.

RESULTS

Complete evaluation of the fetal heart was impossible at 10 weeks; the total success rate increased from 45% at 11 weeks to 90% between 12 and 14 weeks and 100% at 15 weeks. Between 10 and 13 weeks, TVS was superior to TAS. At 14 weeks, both methods were similar to each other, and at 15 weeks, TAS allowed adequate visualization of all structures. Linear regression analysis showed a significant correlation between the interrogated parameters and gestational age, crown-rump length, and biparietal diameter (P < .05). The ratio of right and left ventricular diameters and the ratio of pulmonary trunk and aortic diameters were constant.

CONCLUSIONS

Early fetal heart evaluation by TVS or TAS or both is reasonable and feasible. Our normative data could be helpful for understanding the normal development of the fetal heart and great arteries and for detection of cardiac defects in early pregnancy.

Fetal echocardiography during routine first-trimester screening: a feasibility study in an unselected population

OBJECTIVE

To evaluate the feasibility of obtaining standard echocardiographic views of the fetal heart during routine first-trimester screening and construct reference ranges for cardiac biometry at 11 + 0 to 13 + 6 weeks of gestation.

METHODS

A cross-sectional study of 584 fetuses in an unselected population. Viable pregnancies with a crown-rump length (CRL) of 41-78 mm were included. Echocardiography was performed by a single obstetrician using a 5 to 7.5 MHz vaginal transducer. The course and outcome of pregnancies were recorded and information on the babies was obtained in all cases.

RESULTS

A completely satisfactory visualization of the fetal heart structures was possible in 58% (43%, 56% and 62% at 11, 12 and 13 weeks, respectively). Reference ranges were constructed from the measurements of cardiac ventricles, their outflow tracts, and cardiothoracic circumference ratio in relation to CRL.

CONCLUSION

Standard echocardiograhic views of the fetal heart can be obtained at 11 + 0 to 13 + 6 weeks of gestation using the transvaginal approach. New reference ranges were established for fetal cardiac biometry at 11 + 0 to 13 + 6 weeks of gestation.

Cardiac Circumference Measurement: Possible Screening Tool in Early Pregnancy for Anomalous Cardiac Development

OBJECTIVE

In this study, cardiac circumference (CC), measured by transvaginal sonography, was analyzed to determine the growth during the early stage of pregnancy and its relationship to abdominal circumference and femur length (FL).

METHODS

Biometric measurements, including CC, were obtained in 1,182 euploid fetuses at 9-16 weeks' gestation. The CC measurements were related to gestational age (GA), abdominal circumference, and FL. The corresponding 95% confidence intervals were calculated.

RESULTS

A linear growth function was observed between CC (mm) and GA (days) (r2 = 0.601; p < 0.0001; y = 0.573 GA - 24.185). Similarly, a good correlation is described with a linear function between CC (mm) and abdominal circumference (mm) (r2 = 0.70; p < 0.0001; y = 0.343 AC + 3.696) and between CC (mm) and FL (mm) (r2 = 0.626; p < 0.0001; y = 1.335 FL + 14.444). The regression analysis that best correlates the dependent variable CC (mm) with the independent variables, GA (days), abdominal circumference (mm), and FL (mm), is: y = 0.137 GA + 0.235 AC + 0.199 FL - 3.303 (r2 = 0.708; p < 0.0001).

CONCLUSION

Our results provide normative data of the growth of the CC in early pregnancy. The good correlation described between CC and abdominal circumference and FL suggests that cardiac measurements in early pregnancy alone, or related to other fetal biometric parameters, could be used as a screening tool to identify fetuses at risk for abnormal heart development.

Counselling following a diagnosis of congenital heart disease

Counselling the parents following a diagnosis of fetal congenital heart disease (CHD) is as important a task for the fetal cardiologist, as the skill involved in achieving an accurate diagnosis. The counsellor will base prognosis not only on the diagnosis itself but also on the security of diagnosis, the stage in gestation and potential for change, the association with extracardiac malformations and the known results of treatment. Depending on the gestational age and legal situation the counsellor is operating in, termination of pregnancy may be one of the options to consider and one that should always be raised in discussion. Thus, the parents may be in the position of making a crucial decision concerning the management of the pregnancy on the basis of the information received, so it is vital that the counsellor is truly able to communicate with them, whatever be their level of understanding.

Long term cardiac follow up of severe twin to twin transfusion syndrome after intrauterine laser coagulation

OBJECTIVE

To assess long term changes in cardiac morphology and function in survivors of severe twin to twin transfusion syndrome (TTTS) after intrauterine laser coagulation of placental anastomoses.

DESIGN

Prospective follow up of fetuses with severe TTTS treated by laser coagulation of intrauterine placental anastomoses. Fetal echocardiography and Doppler studies of feto-placental haemodynamic function were performed at the time of laser coagulation (median gestational age of 21.7 weeks). Postnatal cardiac follow up included a detailed echocardiographic study of systolic and diastolic cardiac function at a median age of 21.1 months.

SETTING

Paediatric cardiology unit.

PATIENTS

89 survivors from 73 consecutive pregnancies with severe TTTS.

RESULTS

Before laser treatment, 28 of 51 (54.9%) recipient twins had typical signs of cardiac dysfunction due to volume overload and 9 of 38 (23.7%) donors had absent or reversed end diastolic flow in the umbilical artery. Echocardiography was normal in 87.6% of the survivors (34 of 38 donors, 44 of 51 recipients). The prevalence of congenital heart disease and particularly of pulmonary stenosis, which was recorded only in recipients, was increased in comparison with the general population (congenital heart disease, 10 of 89 (11.2%) v 0.3%; pulmonary stenosis, 4 of 51 (7.8%) v 0.03%). Findings before laser treatment were not correlated with the development of structural heart disease.

CONCLUSIONS

Despite the high rate and severity of prenatal cardiac overload in recipients, the majority of cases of TTTS are normalised after laser treatment. However, given the increased prevalence of congenital heart disease and in particular pulmonary stenosis, intrauterine and postnatal follow up is warranted.