Congenital heart disease and extracardiac anomalies: associations and indications for fetal echocardiography

Fetal echocardiography: accuracy and limitations in a population at high and low risk for heart defects

OBJECTIVE

Our objective was to assess the accuracy of prenatal echocardiography in detecting congenital heart defects in patients at high and low risk for structural cardiac anomalies.

STUDY DESIGN

Sixty-nine consecutive fetuses with congenital heart defects who had had prenatal ultrasonography at greater than or equal to 18 weeks' gestation were evaluated to determine the accuracy of prenatal ultrasonography in identifying structural cardiac defects. Thirty-nine patients were at high risk and 30 patients were at low risk for cardiac anomalies. All fetuses were scanned with standard four-chamber and outflow tract views. Data concerning extracardiac anomalies and karyotypic abnormalities were tabulated. The accuracy of the four-chamber view alone in identifying congenital heart defects was evaluated.

RESULTS

Fifty-seven of 69 fetuses (83%) were prenatally identified ultrasonographically as having a heart defect. There was no difference in the sensitivity of detecting cardiac anomalies between high-risk and low-risk groups. When the four-chamber view was used, only 63% of fetuses were recognized as having an abnormal heart. Extracardiac anomalies were noted in 36% and karyotypic abnormalities in 17% of patients.

CONCLUSION

The four-chamber and outflow tract views done routinely in an ultrasonography laboratory seeing a mixed population of patients was successful in detecting 83% of fetuses with structural cardiac malformations. Because 43% of the fetuses with heart defects were referred for low-risk indications, systematic ultrasonographic examination of the fetal heart should not be reserved only for those at high risk.

Cardiac ultrasound: its role in the recognition and management of fetal heart disease

This article briefly reviews the role of ultrasound scanning in the diagnosis and management of fetal cardiac disease. Currently, the potential exists for the accurate identification of a wide range of cardiac defects and for the diagnosis and successful management of many cardiac rhythm disturbances. Considerable benefit is derived for families with previously affected children when a normal fetal cardiac ultrasound report can be provided.

Fetal choroid plexus cysts in the second trimester of pregnancy: a cause for concern

Controversy surrounds the issue of recommending cytogenetic studies in second-trimester fetuses with fetal choroid plexus cysts. To assist in clarifying this issue, a prospective study was designed to describe the association between fetal choroid plexus cysts and aneuploidy in a large population. During a 3-year period 7350 women at 15 to 22 weeks' gestation underwent an ultrasonographic evaluation. Fetal choroid plexus cysts were diagnosed in 71 (0.96%) of these pregnancies. Sixty-two of the 71 patients elected to undergo amniocentesis. An abnormal karyotype was identified in four (6.4%) of these fetuses. One fetus had trisomy 21, and three fetuses were diagnosed with trisomy 18. These data indicate that it is reasonable to offer genetic counseling and cytogenetic studies in those patients identified as having a fetal choroid plexus cyst.

Color Doppler flow mapping of fetal heart

Color Doppler flow mapping of fetal heart was performed in 582 fetuses between 16 and 38 weeks of gestation. Congenital heart diseases were excluded in 522 fetuses correctly. In 59 fetuses structural and/or functional cardiac abnormalities were diagnosed. In one fetus small multiple ventricular septal defects were missed. The most important additional information obtained by color Doppler flow mapping was: (1) Diagnosis of insufficiencies of atrioventricular valves; (2) Demonstration of turbulent high velocity jet in stenosis of semilunar valve; (3) Reverse flow in ascending aorta in atresia of aortic valves and on ductus arteriosus and main pulmonary artery in atresia of pulmonary valves; (4) Reverse perfusion of ductus arteriosus and main pulmonary artery as well as an antegrade turbulent high velocity jet in severe pulmonary stenosis as part of tetralogy of Fallot; (5) Bidirectional interventricular shunting of blood in ventricular septal defect. Color Doppler flow mapping allows rapid screening for flow abnormalities of the fetal heart. Exact localisation of sample volume by pulsed wave Doppler in area of abnormal flow pattern is possible, thus significantly reducing the Doppler examination time. The accuracy of prenatal diagnosis of congenital heart diseases is improved by application of color Doppler flow mapping, in particular in presence of complex cardiac defects.

Choroid plexus cysts and chromosomal defects

During a 4-year period, 83 pregnant women with fetal choroid plexus cysts were investigated in our unit. Abnormal karyotypes were found in 20 fetuses, including trisomy 18 (n = 16), trisomy 13 (n = 1), triploidy (n = 1) and translocation Down's syndrome (n = 2). All fetuses with chromosomal defects had structural malformations in addition to the choroid plexus cysts.

Congenital polyvalvular disease in trisomy 18: echocardiographic diagnosis

Congenital heart disease is known to occur in greater than 90% of patients with trisomy 18, with ventricular septal defect and patent ductus arteriosus being the most frequently encountered lesions. The presence of congenital polyvalvular disease in trisomy 18 as assessed by pathological specimens has also been noted. Echocardiograms were obtained in 15 patients with trisomy 18 and in 12 infants with dysmorphic features, who did not have chromosomal abnormalities, in order to obtain an echocardiographic assessment of the frequency of polyvalvular disease in living patients with trisomy 18. In this series all patients with trisomy 18 had structural defects (seven ventricular septal defects, three patent ductus arteriosus, five both). All trisomy 18 patients also had congenital polyvalvular disease with six patients having four affected valves, five patients having three affected valves, and four patients with two affected valves. In patients with normal chromosomes, two had a single abnormal valve, and structural lesions included patent ductus arteriosus (3), ventricular septal defect (2), pulmonary atresia with ventricular septal defect (1), transposition of the great arteries (1), and atrioventricular canal with patent ductus arteriosus and coarctation (1). In infants with features suggestive of trisomy 18, structural cardiac lesions are a nonspecific finding. However, the presence of polyvalvular disease may be a more specific and useful adjunct to other clinical investigations pending chromosomal analysis for definitive diagnosis.

Fetal echocardiography: the role of the screening procedure

1841 pregnant women without any risk factor for heart malformation of the fetus underwent an echocardiographic screening at an average gestational age of 23 weeks. Seven cases of heart diseases were diagnosed (0.38%), of which one died in utero at 28 weeks and another one was interrupted. In four cases the karyotype was carried out prenatally, while in the remaining three it was performed only after birth. There were 11 false-negative (0.59%), mainly concerning anomalies of minor clinical significance. Within this group, two newborns with interatrial defect of the ostium secundum type appeared to be affected by trisomy 21. Therefore, the rate of congenital heart diseases in live births not at risk (0.86%) was in line with the data reported in paediatric literature. On the other hand, the association with chromosomal anomalies was surprisingly frequent (4 out of the 9 karyotypes performed were anomalous). Such finding should be verified by studying a larger non-selected population. However, a fetal karyotype should be offered, for its practical consequences, also in those cases of cardiac anomalies of lesser clinical significance.

Flow analysis in the pulmonary trunc in fetuses with tetralogy of Fallot by colour Doppler flow mapping; two case reports

Prenatal diagnosis of tetralogy of Fallot by two-dimensional echocardiography, which is based on demonstration of a ventricular septal defect and a large overriding aorta, is difficult. In the majority of cases the main pulmonary artery is small. In utero, there is no pathologically increased degree of the physiological right-ventricular hypertrophy. Colour Doppler flow mapping of reverse flow from the descending aorta via the ductus arteriosus into the main pulmonary artery is easily demonstrated, and provides an indirect sign of severe right-ventricular outlet obstruction. The technique also differentiates between pulmonary stenosis and atresia; the stenotic jet, even small, is identified by demonstration of high velocities and turbulences in the main pulmonary artery.

Structural cardiac abnormalities in the fetus: reliability of prenatal diagnosis and outcome

The outcomes of 129 pregnancies in which the fetus was found to have a structural cardiac abnormality are reviewed. Over a 30-month period from January 1985 to June 1987, 1924 patients were referred to the British Heart Foundation Research Centre for Perinatal Cardiology at Guy's Hospital for fetal cardiac scanning. A total of 129 structural cardiac abnormalities was diagnosed; 53% of these patients were referred because of an abnormal 'four-chamber view' on ultrasound at the referring hospital; 47 of the pregnancies (69% of the 68 patients referred before 28 weeks) were terminated, and in the remaining 82 pregnancies outcome was poor with only 20 infants (16%) surviving longer than 11 months. The prenatal diagnosis was fully or partly correct in 96% of the 111 cases where it was possible to verify the diagnosis by post-mortem or postnatal diagnosis. In the 82 pregnancies not terminated, 13 of the 22 cases given a moderate or good prognosis survived more than 11 months (59% survival), but only seven of the 60 (12% survival) given a fatal, poor or uncertain prognosis. The benefits of a multidisciplinary approach are discussed.

Fetal echocardiography in the diagnosis of congenital heart disease

Fetal echocardiography provides an opportunity to diagnose congenital heart disease as early as the midtrimester of pregnancy, allowing for proper planning of perinatal care and counselling of the parents. This paper reviews the accuracy and outcomes of fetal cardiac ultrasound studies at The Prince Charles Hospital over the past 4 years. A total of 43 fetuses, of gestational ages 16-39 weeks, were studied. The indications for these were: previous sibling with cardiac anomaly (16 cases); abnormal heart on obstetric ultrasound scan (USS) (13 cases); abnormalities found on obstetric USS with normal appearing heart (one case); fetal bradycardia (seven cases); fetal tachycardia (four cases); irregular fetal heart beat (two cases). At birth all fetuses assessed because of a previously affected sibling were normal. Of the 13 referred because of structural heart lesions suspected on obstetric USS, eight were abnormal, four were normal and one was terminated without autopsy. Important rhythm disturbances occurred in nine of the 11 referred because of abnormal heart rates. One false positive diagnosis of a possible coarctation was made, and in four cases an abnormality was noted on USS but the diagnosis was not completely correct. Nine of the 19 infants with abnormalities detected have died. Fetal echocardiography is an accurate and useful method of diagnosing congenital heart disease in utero. Although the mortality of affected fetuses is high, antenatal diagnosis allows planning of medical care and offers the greatest chance of a successful outcome.

Fetal two-dimensional Doppler echocardiography (colour flow mapping) and its place in prenatal diagnosis

One hundred and fifty fetuses between 16 and 38 weeks of gestation were studied by fetal echocardiography using colour-coded two-dimensional Doppler echocardiography. Two-dimensional, M-mode, and Doppler spectral analyses were also performed. In 14 fetuses, structural and/or functional abnormalities were detected. Abnormalities were correctly ruled out in all the other fetuses. The advantages of two-dimensional Doppler echocardiography are (1) rapid screening for flow abnormalities in the fetal heart, and thus shortening of the Doppler examination time; (2) rapid diagnosis of valvular regurgitation, valvular stenosis, and abnormal shunting of blood across the interatrial and interventricular septa; and (3) facilitation of the diagnosis of complex congenital heart defects which in certain cases is possible only by using two-dimensional Doppler echocardiography.

Prenatal detection of congenital heart disease: factors affecting obstetric management and survival

Our recent experience in the diagnosis and management of fetal congenital heart disease is presented. During an 18-month period from January 1985 to June 1986, 1757 fetal echocardiograms were performed on a total of 989 antenatal patients. Cardiac anomalies were accurately predicted in 74 cases, 34 of which were associated with extracardiac or chromosomal anomalies. Twenty-three pregnancies were electively terminated. Currently the survival rate for ongoing pregnancies is 17%. A false negative diagnosis was made in 16 cases, the majority involving minor anomalies with a good prognosis and a survival rate of 81%. Prenatal detection of congenital heart disease places the fetus at high risk for chromosomal and extracardiac anomalies. Congenital heart disease detectable during pregnancy is usually severe and associated with a poor long-term prognosis. Termination of the pregnancy may be a reasonable option if a severe anomaly is detected early in pregnancy.

Abnormal antenatal ultrasound findings and subsequent handicap

The modern ultrasound technique in its various modes, real-time B-mode, M-mode, continuous and pulsed wave Doppler ultrasound, makes it possible to study in detail the fetal anatomy and function in utero. Fetometry allows for the evaluation of fetal size and growth and for detecting growth-retarded or macrosomic fetuses. Ultrasound seems, at present, to be the best method available in the detection of the growth-retarded fetus who is at risk of developing perinatal complications and subsequent handicap. Ultrasound can also be used when fetal growth retardation is suspected on clinical grounds. An absolute prerequisite for the proper use of ultrasound fetometry is the estimation of gestational age in early pregnancy. The high resolution of modern ultrasound scanners allows the antenatal detection of even minor fetal structural abnormalities. When lethal malformations are detected early in pregnancy, selective termination of pregnancy can be considered. Fetal abnormality detected in late pregnancy allows for optimal timing and mode of delivery leading to improved management and outcome, thus lowering the risks of subsequent handicap. Ultrasound examination of the extrafetal structures, e.g. umbilical cord, placenta and amniotic fluid volume, may add valuable clinical information. The finding of severe oligohydramnios is associated with increased perinatal mortality and morbidity. Fetal circulation can be evaluated by using the combination of real-time and pulsed Doppler ultrasound or, alternatively, by employing continuous wave Doppler ultrasound alone. Pathological changes in the blood velocity waveforms recorded from the fetal and umbilical arteries may signify very early signs of fetal hypoxia. The method has the potential of becoming a useful clinical method for fetal surveillance. The guidelines for a proper application in the perinatal medicine of the Doppler method have, however, not yet been established. In fetuses with cardiac arrhythmia and/or cardiac malformation, the Doppler investigation of the fetal circulation can be used to evaluate the haemodynamic alterations and, in cases of intrauterine treatment, to supervise and monitor the therapeutic effects. Fetal motor function can be followed and quantified with real-time ultrasound. Abnormal motor activity might indicate bad perinatal outcome. The predictive capacity of the test is increased when several variables are combined (e.g. the fetal biophysical profile score).(ABSTRACT TRUNCATED AT 400 WORDS)

The frequency of aneuploidy in prenatally diagnosed congenital heart disease: an indication for fetal karyotyping

The frequency of chromosomal abnormalities in infants with congenital heart disease has been estimated from postnatal clinic data to be 5% to 10%. Over an 18-month period we performed fetal echocardiograms on 502 fetuses and found cardiac anomalies in 34. Eleven of these fetuses (32%) had abnormal chromosomes. This marked discrepancy from the data found in the pediatric literature may relate to nonviable fetuses identified in utero, who escape pediatric case identification. We conclude that in cases of fetal heart disease the workup should include either amniocentesis or fetal blood sampling for chromosome analysis. The information can be used for complete parental counseling and for managing delivery and neonatal care.

Sonographic detection of fetuses with trisomies 13 and 18: accuracy and limitations

Nine fetuses having trisomy 13 and 15 fetuses with trisomy 18 were diagnosed by cytogenetic studies and also underwent a sonogram between 15 and 40 weeks. All nine fetuses with trisomy 13 had been prospectively identified as having sonographic findings suggestive of trisomy 13. Twelve of the 15 fetuses with trisomy 18 had sonographic abnormalities compatible with trisomy 18. Findings included abnormalities of the face and head, extremities, and diaphragmatic hernia. This report examines criteria for the ultrasound diagnosis of trisomies 13 and 18 and describes the accuracy of prenatal sonography for these diagnoses.

Sonographic identification of second-trimester fetuses with Down's syndrome

Fetuses with Down's syndrome are more likely than normal fetuses to have a thickened nuchal skin fold and relatively short femurs on ultrasound examination in the second trimester. We evaluated these measures in more than 5500 fetuses, including 28 who were later found to have Down's syndrome by means of amniocentesis with cytogenetic analysis. Normal femur length was established as a function of biparietal diameter in 192 of the normal fetuses. We found that with use of a nuchal skin-fold thickness of 6 mm or more and a ratio of actual to expected femur length of 0.91 or less, fetuses with Down's syndrome could be identified with a sensitivity of 75 percent and a specificity of 98 percent. When other anomalies, such as an atrioventricular canal and meconium peritonitis, were added to these two criteria, the sensitivity of sonographic detection of Down's syndrome in the second-trimester fetus rose to 82 percent. The potential predictive value of these sonographic signs far exceeds that of advanced maternal age and low alpha-fetoprotein levels, which currently identify only 10 to 30 percent of affected fetuses. We recommend that fetuses with a thickened nuchal skin fold or shortened femurs on ultrasound examination be evaluated for Down's syndrome by amniocentesis and cytogenetic analysis.

A sonographic screening method for Down syndrome

We describe a potential screening method for the second trimester detection of the fetus with Down syndrome by the use of standard sonographic biometry. Retrospective assessment of the biparietal diameter, femur length, and biparietal diameter/femur length ratio in 55 fetuses with Down syndrome and 544 control fetuses was performed at two medical centers. Adequate numbers of cases and controls were available to permit statistically significant comparisons between the groups at 15 to 23 weeks' gestation. Fetuses with Down syndrome displayed no statistically significant differences in the cephalic index or the biparietal diameter compared with controls at a given gestational age. Significant femur length shortening was observed, but the greatest statistical difference was noted for the biparietal diameter/femur length ratio. This ratio was found to decrease with gestational age in the normal population and was consistently elevated in the Down syndrome population (compared with control) throughout the second trimester. With a cutoff value of 1.5 SD above the normal population mean for the biparietal diameter/femur length ratio, 50% to 70% of fetuses with Down syndrome could be identified in 6% of the total population (p less than 0.0001). This preliminary study suggests that the biparietal diameter/femur length ratio may prove superior to current Down syndrome screening methods and, as a third independent variable, may significantly enhance the sensitivity and specificity of combined maternal age/maternal serum alpha-fetoprotein screening modalities.