Correlation between echocardiographic and morphological investigations of lesions of the tricuspid valve diagnosed during fetal life

Hemodynamics During Development and Postnatal Life

A well-developed heart is essential for embryonic survival. There are constant interactions between cardiac tissue motion and blood flow, which determine the heart shape itself. Hemodynamic forces are a powerful stimulus for cardiac growth and differentiation. Therefore, it is particularly interesting to investigate how the blood flows through the heart and how hemodynamics is linked to a particular species and its development, including human. The appropriate patterns and magnitude of hemodynamic stresses are necessary for the proper formation of cardiac structures, and hemodynamic perturbations have been found to cause malformations via identifiable mechanobiological molecular pathways. There are significant differences in cardiac hemodynamics among vertebrate species, which go hand in hand with the presence of specific anatomical structures. However, strong similarities during development suggest a common pattern for cardiac hemodynamics in human adults. In the human fetal heart, hemodynamic abnormalities during gestation are known to progress to congenital heart malformations by birth. In this chapter, we discuss the current state of the knowledge of the prenatal cardiac hemodynamics, as discovered through small and large animal models, as well as from clinical investigations, with parallels gathered from the poikilotherm vertebrates that emulate some hemodynamically significant human congenital heart diseases.

Fetal Heart Size: A Comparison Between the Point-to-Point Trace and Automated Ellipse Methods Between 20 and 40 Weeks' Gestation

OBJECTIVES

To evaluate whether the global area and circumference of the heart varies between two measurement techniques: the point-to-point trace and the electronic ellipse methods.

METHODS

The epicardial border of the 4-chamber view was measured in 200 fetuses between 20 and 40 weeks' gestation, from which the area and circumference using the point-to-point trace and electronic ellipse were measured. Analysis of variance, correlation, and regression analysis using fractional polynomials and 7 independent variables (head circumference, biparietal diameter, abdominal circumference, femur length, estimated fetal weight, mean ultrasound gestational age, and last menstrual period gestational age) were performed.

RESULTS

The correlation between the mean ultrasound gestational age and last menstrual period gestational age was 0.9880 (5% confidence limit, 0.9716; 95% confidence limit, 0.9880), with an R² of 0.9762. The R² value for the 7 independent variables regressed against the area and circumference using the point-to-point trace and electronic ellipse methods ranged between 0.885 and 0.965. Comparison of Z scores between this study and previous publications demonstrated that there were differences and similarities, depending on whether the area or circumference was measured.

CONCLUSIONS

This study shows high R² values when comparing measurements of the area and circumference against 7 independent variables, irrespective of whether the point-to-point trace or the electronic ellipse method was used to obtain the measurements. A calculator to evaluate the area and circumference is provided, using 7 independent variables from which Z scores and percentiles for individual measurements can be computed.

Diagnosis and management of fetal heart failure

Congestive fetal heart failure, defined as inability of the heart to deliver adequate blood flow to organs such as the brain, liver, and kidneys, is a common final outcome of many intrauterine disease states that may lead to fetal demise. Advances in fetal medicine during the past 3 decades now provide the diagnostic tools to detect and also treat conditions that may lead to fetal heart failure. Fetal echocardiographic findings depend on severity of diastolic and systolic dysfunction of both ventricles. At an advanced stage, findings include cardiomegaly; valvar regurgitation; venous congestion; fetal edema and effusions; oligohydramnios; and preferential shunting of blood flow to the brain, heart, and adrenals in the distressed fetus. A useful diagnostic tool to quantify severity of heart failure is the cardiovascular profile score, which is a composite score based on 5 different echocardiographic parameters. To predict outcomes, the score should be interpreted in the context of the underlying disease, as different causes of intrauterine heart failure may have highly variable outcomes. Low fetal cardiac output may result from a myocardial disease (cardiomyopathy, myocarditis, ischemia), abnormal loading conditions (arterial hypertension, obstructive structural heart disease, atrioventricular malformations, twin-to-twin transfusion), arrhythmia, or external cardiac compression (pleural and/or pericardial effusions, cardiac tumours). Treatment options are available for several of these conditions.

Fistulous communications with the coronary arteries in the setting of hypoplastic ventricles

Neonates born with hypoplastic left heart syndrome now have a remarkably improved prognosis compared with the situation existing before the development of the Norwood sequence of operative procedures. Some of those born with hypoplastic right ventricles in the setting of pulmonary atresia with an intact ventricular septum, however, still have a relatively poor prognosis. In part this reflects the presence of fistulous communication between the cavity of the right hypoplastic right ventricle and the coronary arterial tree. Such fistulous communications are now increasingly recognised as being important in the setting of hypoplastic left heart syndrome. In this brief review, we describe the anatomy of the communications. Those found with hypoplastic right ventricles are seen most frequently when the cavity of the ventricle effectively represents only the inlet, this in turn reflecting mural overgrowth of the apical trabecular and outlet components during foetal development. This almost certainly reflects an earlier appearance of the pulmonary valvar lesion that promotes the cavitary hypoplasia. In those with hypoplastic left ventricles, the key feature differentiating those with fistulous communications is the presence of a patent mitral valve, since the left ventricle is typically no more than a virtual slit in postero-inferior ventricular wall in the setting of mitral valvar atresia or absence of the left atrioventricular connection.

Morphometric study of the ventricular segment of the human fetal heart between 13 and 20 weeks' gestation

Our objective was to determine the normal dimensions of the ventricular segment of the human fetal heart between 13 and 20 weeks' gestation.

STUDY DESIGN

103 hearts obtained by necropsy were dissected and measurements of different portions of ventricles were determined under stereoscopic magnification. In each ventricle were measured anteroposterior and lateral diameters, inlet and outlet length, and thickness of walls at different levels. Our results showed the cardiac apex was constituted by the left ventricle in 68.9% of the hearts. Both ventricles showed linear growth during this period of fetal development. Ranges in median values of external and internal ventricular measurements were determined. The left ventricular wall was thicker than the right, and the right ventricular cavity was larger. This study provides morphometric reference information concerning the dimensions and growth of both ventricles of the fetal heart, which may be useful in pediatric cardiac surgery and echocardiography.

Fetal congestive heart failure

Fetal echocardiography is used in the diagnosis of many forms of congenital heart disease, and in the assessment of the prognosis of cardiac lesions based on their anatomy and presentation in utero. However, the presence of signs of fetal heart failure such as hydrops or valvular regurgitation makes the assessment of prognosis more difficult. A tool for this assessment is the 'cardiovascular profile score', which combines ultrasonic markers of fetal cardiovascular unwellness based on univariate parameters that have been correlated with perinatal mortality. This profile could become the 'heart failure score' and could potentially be used in much the same way as and in combination with the biophysical profile score. This article will present a straightforward method for rapid evaluation of a fetus that may have congestive heart failure.

Likelihood ratio for trisomy 21 in fetuses with tricuspid regurgitation at the 11 to 13 + 6-week scan

OBJECTIVE

To determine the likelihood ratio for trisomy 21 in fetuses with tricuspid regurgitation at the 11 to 13 + 6-week scan.

METHODS

Fetal echocardiography was carried out by specialist pediatric cardiologists in 742 singleton pregnancies at 11 to 13 + 6 weeks' gestation and pulsed wave Doppler was used to ascertain the presence or absence of tricuspid regurgitation. To avoid confusion with other adjacent signals, a strict definition of tricuspid regurgitation was used, in that it had to occupy at least half of systole and reach a velocity of over 80 cm/s. The fetal crown-rump length (CRL) and the nuchal translucency (NT) thickness were measured and the presence of any congenital heart abnormality noted. Follow-up of the pregnancy was carried out to determine the presence of chromosomal abnormalities. The likelihood ratio for trisomy 21 in fetuses with and without tricuspid regurgitation was determined.

RESULTS

The tricuspid valve was successfully examined in 718 (96.8%) cases. Tricuspid regurgitation was present in 39 (8.5%) of the 458 chromosomally normal fetuses, in 82 (65.1%) of the 126 with trisomy 21, in 44 (53.0%) of the 83 with trisomy 18 or 13, and in 11 (21.6%) of the 51 with other chromosomal defects. The prevalence of tricuspid regurgitation was also associated with fetal CRL, delta NT and the presence of cardiac defects. Logistic regression analysis, irrespective of cardiac defects, demonstrated that in the chromosomally normal fetuses significant independent prediction of the likelihood of tricuspid regurgitation was provided by fetal delta NT (odds ratio (OR), 1.26; 95% CI, 1.34-1.41; P < 0.0001), while in trisomy 21 fetuses prediction was provided by CRL (OR, 0.94; 95% CI, 0.89-0.99; P = 0.021). The likelihood ratio for trisomy 21 for tricuspid regurgitation was derived by dividing the likelihood in trisomy 21 by that in normal fetuses. In the chromosomally normal fetuses, the prevalence of tricuspid regurgitation in those with cardiac defects was 46.9% and 5.6% in those without cardiac defects, and the likelihood ratio of tricuspid regurgitation for cardiac defects was 8.4.

CONCLUSION

At 11 to 13 + 6 weeks' gestation, there is a high association between tricuspid regurgitation and trisomy 21, as well as other chromosomal defects. The prevalence of tricuspid regurgitation increases with fetal NT thickness and is substantially higher in those with, than those without, a cardiac defect.

Morphometric study of the human fetal heart I. Arterial segment

This study measured the dimensions of the great arteries of normal human fetal hearts at an early fetal stage (between 13-20 weeks post-fertilization) in 103 fetuses obtained by necropsy. Different segments of the aorta and the pulmonary artery were dissected and their external diameters measured under stereoscopic magnification. All segments showed linear growth during this period of fetal development. Ranges in median values of external diameters associated with the pulmonary artery were: 2.1-4.2 mm for the valve ring; 2.2-4.2 mm for the main pulmonary trunk; 1.2-2.5 mm for the right pulmonary artery; 0.9-2.18 mm for the left pulmonary artery; and 4.0-8.0 mm for the length of the main pulmonary trunk. Similarly, in the aorta, median diameters were: 2.1-4.2 mm for the ascending aorta; 1.92-3.8 mm for the aortic arch; 1.45-3.0 mm for the aortic isthmus; and 1.75 -3.35 mm for the descending aorta. The diameter of the ductus arteriosus ranged between 1.2-2.45 mm. The growth rates of the pulmonary artery and the aorta were similar. The diameter of the ascending aorta was found to be greater than that of the descending aorta and the right pulmonary artery was wider than the left pulmonary artery. In addition, the magnitude of growth in the various aortic segments was different and the ratios obtained between the aortic isthmus and the ascending and descending aortae, ranged between 0.66-0.93. This study provides important morphometric reference information concerning the dimensions and growth of the great arteries of the fetal heart and has clinical application in pediatric cardiac surgery and echocardiography.

Sonographic features of Ebstein anomaly associated with hydrops fetalis: a report of two cases

Ebstein anomaly, an abnormally low insertion of the tricuspid valve, occurs in 0.5% of patients with congenital heart disease. In rare cases, this disorder may be complicated by congestive heart failure in utero and hydrops fetalis. This article reports the prenatal sonographic features of 2 cases of Ebstein anomaly associated with hydrops fetalis. In both cases, fetal echocardiography was performed at 34 weeks of gestation. The 4-chamber view showed fetal cardiomegaly and pericardial effusion. In both cases, the annular attachment of the tricuspid valve leaflets was difficult to demonstrate and so distal that it could easily be confused with papillary muscle in the right ventricular wall. Poor fetal cardiac hemodynamics with severe tricuspid regurgitation was demonstrated by pulsed Doppler imaging. Pulmonary regurgitation was also clearly demonstrated in both cases. Preterm delivery with stillbirth occurred in both cases. Autopsies confirmed the very distal displacement of the tricuspid valve insertion, close to the apex, and enlargement of the right atrium.

The normal offset of the tricuspid septal leaflet in the fetus

OBJECTIVE

To quantify the normal distance between the insertion of the medial leaflets of the mitral valve and tricuspid valve in the fetal heart. This mitral valve-tricuspid valve distance was compared with the distance from known cases of Ebstein anomaly.

METHODS

An apical 4-chamber view was obtained at end diastole in fetuses between 18 and 41 weeks' gestation. Calipers were placed parallel to the ventricular septum, with 1 caliper on the medial insertion of the mitral valve and a second caliper on the medial insertion of the tricuspid valve. The distance recorded was plotted against gestational age. Statistical analysis was performed by descriptive and linear regression techniques.

RESULTS

One hundred forty-five fetuses were studied. The mean +/- SD mitral valve-tricuspid valve distance in the second trimester was 2.8 +/- 0.9 mm with a range of 1.2 to 5.0 mm; in the third trimester it was 4.6 +/- 1.1 mm with a range of 2.2 to 6.9 mm. Regression analysis showed that with each 1-week increase in gestational age, there was an increase of 0.15 mm in separation between the medial leaflets of the mitral valve and tricuspid valve (beta = 0.15 +/- 0.011).

CONCLUSIONS

A positive correlation between mitral valve-tricuspid valve distance and advancing gestational age was found. The reference range described allows for the identification of a fetal heart with normal variation in the mitral valve-tricuspid valve distance. Further downward displacement of the medial tricuspid cusp suggests the possibility of Ebstein anomaly.

Right ventricular function in the human fetus

Fetal RV function is critical for survival and normal cardiovascular development. Doppler can be used to assess function. Combined with wise use of imaging techniques, the cause of abnormalities can be assessed. Both congenital heart defects and other cardiovascular defects can lead to hydrops and death. Serial semi-quantitation of fetal heart failure can be done with a Cardiovascular Profile score.

The spectrum of fetal cardiac malformations

Increasingly, paediatric cardiologists are called upon to diagnose cardiac malformations prenatally. In the main, the types of malformation seen during fetal life will be similar to those documented postnatally, but the frequency with which they are encountered, as well as the views that can be used for diagnosis, will be different. This review aims to describe the anatomic spectrum of malformations seen in 917 fetal hearts examined consecutively following prenatal diagnosis. The distribution of anomalies is illustrated in terms of a simple sweep through the fetal thorax passing from the four-chamber plane to the outflow tracts, and then to more cranial views of the mediastinum. Two-thirds of the anomalies described would have been detectable in the four-chamber plane. Some, such as tricuspid valvar abnormalities, will alter the normal appearances of the four-chambers dramatically. In terms of the overall spectrum, however, such obvious abnormalities only form a minor part of the total number. Others, such as atrioventricular septal defect, will often require closer inspection of intracardiac anatomy, but will make up a large proportion of the entire cohort. Up to one third of the anomalies in the series would have required views more cranial to the four-chamber plane of section. In these, it would have been necessary to examine the nature of the left ventricular outflow tract, the crossing of the two outflows, or else the arterial arches in order to secure detection. In the fetus, these and other planes must be considered by the echocardiographer in order completely to detect and document the entire spectrum of cardiac abnormalities likely to be encountered.

Prenatal diagnosis of severe tricuspid insufficiency in Ebstein's anomaly with pulmonary atresia and intact ventricular septum: a case report

Pulmonary atresia with intact ventricular septum is an uncommon congenital cardiac anomaly which very often present varying degrees of downward displacement and dysplasia of the tricuspid valve. A 23-year-old woman was referred at 23 weeks' gestation because of fetal cardiomegaly detected by routine ultrasonography. Ebstein's anomaly with pulmonary atresia was diagnosed by fetal echocardiography. On pulsed Doppler examination, a severe tricuspid regurgitation was detected. Pulmonary atresia was suspected, as forward flow was not detected into pulmonary artery. The fetus was terminated at 25 weeks. At the postmorterm examination Ebstein's anomaly with pulmonary atresia and intact ventricular septum were confirmed. The finding of right atrial enlargement on an early sonogram should prompt the search for tricuspid valve abnormalities with tricuspid regurgitation and the presence or development of pulmonary atresia or stenosis. With the information provided, early detection of tricuspid valve disease should be possible so that the option of therapeutic abortion can be offered.

Longitudinal observations in normally grown fetuses with tricuspid valve regurgitation: report of 22 cases

Longitudinal observations of tricuspid valve regurgitation were prospectively performed in 22 singleton fetuses with normal anatomy, normal biometry and normal Doppler to determine the characteristics of functional tricuspid valve regurgitation. Tricuspid valve regurgitation was semi-quantified by spatial and temporal Doppler-derived parameters. In 18 cases tricuspid valve regurgitation was part-systolic (early and mid-systolic) and showed little spatial expansion of the jet as examined by colour Doppler flow imaging. In 16 of these 18 cases the maximum velocity of these regurgitant jets was below 2.00 m/s. Four fetuses demonstrated holosystolic regurgitant jets and in addition to the longer duration of these jets, the spatial expansion was also greater and the maximum velocity was slightly higher compared with the part-systolic tricuspid valve regurgitations. Re-examination of the 22 normally grown fetuses showed that tricuspid valve regurgitation was a transient phenomenon. Within a period of one to seven weeks after the diagnosis of tricuspid valve regurgitation, the regurgitation could no longer be demonstrated in any of these cases, including the four fetuses with holosystolic regurgitant jets. Tricuspid valve regurgitation was the only detected abnormality in all of these cases. The fetal outcome of the 22 normally grown fetuses with tricuspid valve regurgitation was unremarkable concerning the evaluated parameters. Although fetal tricuspid valve regurgitation may be a sign of increased preload, afterload or cardiac dysfunction, in most cases tricuspid valve regurgitation is an isolated transient phenomenon with little temporal and spatial expansion; nevertheless in some cases holosystolic tricuspid valve regurgitation may also be an isolated transient finding, and it may be a functional phenomenon.

Tricuspid valve disease. Clinical evaluation, physiopathology, and management

The tricuspid and mitral valves are homologous whose function depends on coordination among components. Isolated tricuspid valve abnormalities are relatively uncommon. Rheumatic disease, chemicals, immunologic and degenerative disorders alter leaflet anatomy and may result in either stenosis, insufficiency or a combination. More often, tricuspid disorders present as a component of congenital syndromes or secondary to pulmonary vascular or let heart disease which alter geometry and function of nonleaflet components.

Outcome in cyanotic neonates with Ebstein's anomaly

Clinical, angiographic, radiographic, and echocardiographic data on 46 neonates with Ebstein's anomaly presenting with cyanosis between 1954 and 1996 were reviewed to determine possible risk factors for mortality. Most patients (67%) presented at birth with 3 cases diagnosed in utero. Mean systemic oxygen saturation was 62+/-12%. An atrial septal defect > or = 4 mm was noted in 20 patients (44%). The patent right ventricle to pulmonary artery connection was present in 10 (22%), and pulmonary atresia was functional in 25 (54%) and anatomic in 11 patients (24%). Fifteen patients (35%) underwent surgical interventions. Total mortality was 70% (vs 14% in acyanotic patients diagnosed during the same time period; p <0.0001) and was related to low cardiac output and hypoxia in 20 patients (62%), postoperative complications in 8 (25%), and sudden death in 4 (13%). Kaplan-Meier survival estimates were 61% at age 1 week (95% confidence interval [CI], 47% to 75%), 48% at age 1 month (95% CI, 34% to 62%), and 36% at both 1 and 5 years of age (95% CI, 22% to 50%). Mortality improved from 81% in 1954 to 1985 to 47% in 1986 to 1996 (p = 0.04). Significant independent predictors of mortality included an atrial septal defect > or = 4 mm (odds ratio [OR] 2.39; p = 0.04), reduced left ventricular function (OR 4.10; p = 0.002), and functional or anatomic pulmonary atresia (OR 2.44, p = 0.003; and OR 5.97, p = 0.004, respectively). An echocardiographic ratio of the combined right atrial and atrialized right ventricular area to the area of the functional right ventricle and left heart >1.0 was 100% predictive of mortality.

Atrio-ventricular valve dysplasia in 22 newborn infants

We retrospectively studied the experience of our institution with isolated dysplasia of one or both atrio-ventricular valves in 22 newborn infants. All patients with associated cardiac malformations were excluded. Ten patients exhibited isolated tricuspid valve dysplasia. One patient had tricuspid valve dysplasia and a dysplastic pulmonary valve. In 10 patients, both atrio-ventricular valves were affected. Finally, mitral valve dysplasia was associated with pulmonary valve stenosis in 1 case. Associated syndromes and/or chromosomal anomalies were: Down syndrome (n=2), trisomy 18 (n=1), Noonan syndrome (n=1), Marfan syndrome (n=3), Ehlers-Danlos and Cutis laxa (n=2). Mortality was 27.2% during follow-up (mean 51 months): 3 patients with chromosomal aneuploidies, 2 patients with severe neonatal Marfan syndrome and 1 with Ehlers-Danlos. Complications were: sustained supra-ventricular tachycardia in 3, neonatal staphylococcal tricuspid valve endocarditis in 1, persistent significant valvular disease in 8. In the remaining 9 survivors, the dysplasia of the atrio-ventricular valves persists with absent or mild incompetence. Beside obvious chromosomal anomalies, newborn infants with dysplastic valves should be investigated for manifestations of connective tissue disorders. This may help to identify new pleiotropic syndromes which include valvular dysplasia as one manifestation.

Fetal Ebstein anomaly--a rare cause of non-immune hydrops

A rare case of fetal Ebstein anomaly presenting as non-immune hydrops fetalis at 28 weeks of gestation is reported along with its review of literature.

The prevalence and clinical significance of fetal tricuspid valve regurgitation with normal heart anatomy

OBJECTIVE

Our purpose was to assess the prevalence, cause, and clinical significance of fetal tricuspid valve regurgitation in structurally normal hearts during indicated fetal echocardiographic examination.

STUDY DESIGN

The prevalence of fetal tricuspid regurgitation was retrospectively evaluated in a group of 733 singleton fetuses referred for routine fetal echocardiography.

RESULTS

The prevalence of this abnormality was 6.8%. Tricuspid valve regurgitation was most frequent in the group referred for fetal echocardiography to evaluate indomethacin exposure, followed by maternal diabetes. Factors associated with tricuspid valve regurgitation included ductal constriction, abnormal heart rhythm, atrial septal aneurysm, congestive heart failure, pericardial effusion, myocardial hypertrophy, and extracardiac malformations. Fetal tricuspid valve regurgitation was trivial in 80% (nonholosystolic, maximum velocity < 2 m/sec) and was significant in 20% (holosystolic, maximum velocity > 2 m/sec). Neonatal follow-up of tricuspid valve regurgitation was unremarkable.

CONCLUSIONS

Fetal tricuspid valve regurgitation with normal heart anatomy was a frequent finding during indicated fetal echocardiographic examination and may indicate abnormal physiologic characteristics (increased preload or afterload, myocardial impairment, or arrhythmia). In the majority of cases (92%) the possible cause may be established. In other cases (8%) there may be "idiopathic" tricuspid valve regurgitation.

Screening for fetal cardiac malformations

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