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

Chromosomal abnormalities in fetuses with congenital heart disease: a meta-analysis

PURPOSE

The aim of this meta-analysis was to evaluate the risk of chromosomal abnormalities in fetuses with congenital heart disease (CHD).

METHODS

Four literature databases were searched until 17th January 2022 using the relevant medical subject heading terms, word variants, and keywords for "congenital heart defect, fetal, and chromosomal abnormalities". The prevalence of overall chromosomal abnormality, aneuploidy, 22q11 deletion, other copy number variants (CNVs), and variants of unknown significance (VOUS) was analyzed.

RESULTS

45 studies met the inclusion criteria for the analysis. The pooled proportion of overall chromosomal abnormalities, aneuploidy, 22q11 deletion, and other CNVs in fetuses with CHD was 23% (95% CI: 20-26%), 19% (95% CI, 16-22%), 2% (95% CI, 2-3%), and 4% (95% CI, 3-5%), respectively. The incidence of overall chromosomal abnormalities, aneuploidy, and other CNVs in non-isolated CHD was higher than in isolated CHD, with odds ratios of 3.08, 3.45, and 4.02, respectively. The incidence of overall chromosomal abnormalities in septal defects was higher than in conotruncal defects and other defects, with odds ratios of 1.60 and 3.61, respectively. In addition, the pooled proportion of VOUS in CHD was 4%.

CONCLUSION

CHD is commonly associated with chromosomal abnormalities. If karyotyping or fluorescence in situ hybridization is normal, chromosomal microarray should be performed to look for submicroscopic abnormalities, especially in fetuses with non-isolated CHD and septal defects.

Whole-Exome Sequencing Identifies Homozygote Nonsense Variants in LMOD2 Gene Causing Infantile Dilated Cardiomyopathy

As an essential component of the sarcomere, actin thin filament stems from the Z-disk extend toward the middle of the sarcomere and overlaps with myosin thick filaments. Elongation of the cardiac thin filament is essential for normal sarcomere maturation and heart function. This process is regulated by the actin-binding proteins Leiomodins (LMODs), among which LMOD2 has recently been identified as a key regulator of thin filament elongation to reach a mature length. Few reports have implicated homozygous loss of function variants of LMOD2 in neonatal dilated cardiomyopathy (DCM) associated with thin filament shortening. We present the fifth case of DCM due to biallelic variants in the LMOD2 gene and the second case with the c.1193G>A (p.W398*) nonsense variant identified by whole-exome sequencing. The proband is a 4-month male infant of Hispanic descent with advanced heart failure. Consistent with previous reports, a myocardial biopsy exhibited remarkably short thin filaments. However, compared to other cases of identical or similar biallelic variants, the patient presented here has an unusually late onset of cardiomyopathy during infancy. Herein, we present the phenotypic and histological features of this variant, confirm the pathogenic impact on protein expression and sarcomere structure, and discuss the current knowledge of LMOD2-related cardiomyopathy.

Care of the Fetus With Congenital Cardiovascular Disease: From Diagnosis to Delivery

BACKGROUND

The majority of congenital cardiovascular disease including structural cardiac defects, abnormalities in cardiac function, and rhythm disturbances can be identified prenatally using screening obstetrical ultrasound with referral for fetal echocardiogram when indicated.

METHODS

Diagnosis of congenital heart disease in the fetus should prompt assessment for extracardiac abnormalities and associated genetic abnormalities once maternal consent is obtained. Pediatric cardiologists, in conjunction with maternal-fetal medicine, neonatology, and cardiothoracic surgery subspecialists, should counsel families about the details of the congenital heart defect as well as prenatal and postnatal management.

RESULTS

Prenatal diagnosis often leads to increased maternal depression and anxiety; however, it decreases morbidity and mortality for many congenital heart defects by allowing clinicians the opportunity to optimize prenatal care and plan delivery based on the specific lesion. Changes in prenatal care can include more frequent assessments through the remainder of the pregnancy, maternal medication administration, or, in selected cases, in utero cardiac catheter intervention or surgical procedures to optimize postnatal outcomes. Delivery planning may include changing the location, timing or mode of delivery to ensure that the neonate is delivered in the most appropriate hospital setting with the required level of hospital staff for immediate postnatal stabilization.

CONCLUSIONS

Based on the specific congenital heart defect, prenatal echocardiogram assessment in late gestation can often aid in predicting the severity of postnatal instability and guide the medical or interventional level of care needed for immediate postnatal intervention to optimize the transition to postnatal circulation.

Investigation of Genetic Alterations in Congenital Heart Diseases in Prenatal Period

The prenatal diagnosis of congenital heart disease (CHD) is important because of mortality risk. The onset of CHD varies, and depending on the malformation type, the risk of aneuploidy is changed. To identify possible genetic alterations in CHD, G-banding, chromosomal microarray or if needed DNA mutation analysis and direct sequence analysis should be planned.

In present study, to identify genetic alterations, cell culture, karyotype analysis, and single nucleotide polymorphism, array analyses were conducted on a total 950 samples. Interventional prenatal genetic examination was performed on 23 (2, 4%, 23/950) fetal CHD cases. Chromosomal abnormalities were detected in 5 out of 23 cases (21, 7%). Detected chromosomal abnormalities were 10q23.2 deletion, trisomy 18, 8p22.3-p23.2 deletion, 8q21.3-q24.3 duplication, 11q24.2q24.5 (9 Mb) deletion, and 8p22p12 (16.8 Mb) deletion. Our study highlights the importance of genetic testing in CHD.

Diagnosis and treatment of fetal cardiac disease: a scientific statement from the American Heart Association

BACKGROUND

The goal of this statement is to review available literature and to put forth a scientific statement on the current practice of fetal cardiac medicine, including the diagnosis and management of fetal cardiovascular disease.

METHODS AND RESULTS

A writing group appointed by the American Heart Association reviewed the available literature pertaining to topics relevant to fetal cardiac medicine, including the diagnosis of congenital heart disease and arrhythmias, assessment of cardiac function and the cardiovascular system, and available treatment options. The American College of Cardiology/American Heart Association classification of recommendations and level of evidence for practice guidelines were applied to the current practice of fetal cardiac medicine. Recommendations relating to the specifics of fetal diagnosis, including the timing of referral for study, indications for referral, and experience suggested for performance and interpretation of studies, are presented. The components of a fetal echocardiogram are described in detail, including descriptions of the assessment of cardiac anatomy, cardiac function, and rhythm. Complementary modalities for fetal cardiac assessment are reviewed, including the use of advanced ultrasound techniques, fetal magnetic resonance imaging, and fetal magnetocardiography and electrocardiography for rhythm assessment. Models for parental counseling and a discussion of parental stress and depression assessments are reviewed. Available fetal therapies, including medical management for arrhythmias or heart failure and closed or open intervention for diseases affecting the cardiovascular system such as twin-twin transfusion syndrome, lung masses, and vascular tumors, are highlighted. Catheter-based intervention strategies to prevent the progression of disease in utero are also discussed. Recommendations for delivery planning strategies for fetuses with congenital heart disease including models based on classification of disease severity and delivery room treatment will be highlighted. Outcome assessment is reviewed to show the benefit of prenatal diagnosis and management as they affect outcome for babies with congenital heart disease.

CONCLUSIONS

Fetal cardiac medicine has evolved considerably over the past 2 decades, predominantly in response to advances in imaging technology and innovations in therapies. The diagnosis of cardiac disease in the fetus is mostly made with ultrasound; however, new technologies, including 3- and 4-dimensional echocardiography, magnetic resonance imaging, and fetal electrocardiography and magnetocardiography, are available. Medical and interventional treatments for select diseases and strategies for delivery room care enable stabilization of high-risk fetuses and contribute to improved outcomes. This statement highlights what is currently known and recommended on the basis of evidence and experience in the rapidly advancing and highly specialized field of fetal cardiac care.

Prevalence and likelihood ratios for aneuploidy in fetuses diagnosed prenatally with isolated congenital cardiac defects

OBJECTIVE

To determine the prevalence and likelihood ratios for aneuploidy in fetuses diagnosed prenatally with isolated congenital cardiac defects.

STUDY DESIGN

Retrospective cohort study over a 16-year period using our computerized perinatal database. Cardiac diagnosis was confirmed before establishing karyotype by prenatal diagnosis or postnatal chromosome testing. The screening efficiency and likelihood ratios for any aneuploidy and for trisomy 21, 18, 13, and 45, X were calculated with 95% confidence intervals.

RESULTS

A total of 233 (0.4%) isolated congenital cardiac defects were diagnosed among 62,111 patients who had obstetric ultrasounds during the study period. The likelihood ratio (LR+) for any aneuploidy was 24.9 (95% confidence interval [CI], 17.8-35.0). The corresponding likelihood ratio for trisomy 21, 18, and 13 were 29.8 (95% CI, 19.6-45.4), 26 (95% CI, 10.5-64.6), and 19.7 (95% CI, 4.7-82.2), respectively.

CONCLUSION

Prenatal diagnosis of congenital cardiac defects is highly associated with aneuploidy.

Prenatal sonographic diagnosis of congenital heart disease and intrauterine growth restriction: a case-control study

PURPOSE

To determine the prevalence of intrauterine growth restriction (IUGR) in cases of congenital heart disease (CHD) and to evaluate whether the prenatal diagnosis of isolated CHD was a significant risk factor for IUGR.

METHODS

We conducted a retrospective case-control study of prenatally detected CHD with delivery at >/=20 weeks' gestation between January 1, 1998, and December 31, 2001. Four groups were analyzed: (1) all cases with CHD, (2) after exclusion of abnormal karyotype, (3) after exclusion of abnormal karyotype and prenatally diagnosed extracardiac anomaly, and (4) after exclusion of abnormal karyotype and prenatally and postnatally diagnosed extracardiac anomaly. The prevalence of IUGR was determined in each of the 4 study groups and was compared with controls.

RESULTS

There were 13,395 deliveries at >/=20 weeks' gestation. Of the 180 cases of CHD, 22.8% were associated with IUGR compared with 11.6% of controls (p < 0.01). In contrast, there was no statistically significant difference in the prevalence of IUGR in the 140 cases of isolated CHD compared with controls (12.9% versus 10.0%).

CONCLUSION

The prenatal detection of isolated CHD does not seem to be associated with IUGR.

Fetal Echocardiography Service in Qatar: Establishment, Challenges and Outcome

A prospective observational study at the newly estab-lished Fetal Medicine Unit, Hamad Hospital, Qatar; evalu-ated the impact of the service on the detection rate of criti-cal congenital heart defects, patterns of referral and sub-sequent yield for structural congenital heart disease in a population with a significant proportion of high risk fac-tors.

Of 391 pregnant females examined between January 2003 and December 2004, 58 (14.8%) had fetal cardiac abnormalities of which 23 (5.8% of total referrals) had major structural malformations of the heart. Cases of fetal congenital heart disease had further evaluation us-ing real time three-dimensional echocardiography (RT3DE) which is new equipment in the paediatric cardi-ology department. All cases with cardiac defects whether minor or major had follow up fetal echocardiography. Neonatal echocardiography confirmed the diagnosis in all cases with major defects (100% specificity). False positive cases that were found to be normal post natal were 1% of the total cases referred (12% of cases with congenital mal-formation). False negative cases were 1% and all had a small ventricular septal defect (VSD) except for one Down's syndrome with a very large VSD.

Three patients needed urgent Caesarean section (CS) deliveries, one with complete heart block (HB) and two with supraventricular tachycardia (SVT). One patient traveled abroad as the fetus had left isomerism and major cardiac defects and complete HB. Fifteen newborns had to receive prostaglandin based on the fetal diagnosis before being seen by paediatric cardiologists. There was no termination of pregnancy due to major cardiac defects even in cases of HLHS.

The preliminary results of this clinic are very satisfac-tory and have affected favorably the outcome of the new-borns with congenital heart defects. It is hoped that the results of this study will encourage more referrals to the FMU.

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.

Accuracy of fetal echocardiography in the routine detection of congenital heart disease among unselected and low risk populations: a systematic review

OBJECTIVE

To determine among unselected and low risk populations the accuracy with which fetal echocardiography during the second trimester detects congenital heart disease.

DESIGN

A systematic review of studies that assess the accuracy of fetal echocardiography.

SETTING

District General Hospital and Tertiary referral centres.

POPULATION

Women during the second trimester attending for ultrasound assessment.

METHODS

General bibliographic databases (e.g. MEDLINE, EMBASE) and specialist computerised databases (e.g. Cochrane Library, National Research Register), grey literature, manual searching of reference lists of primary and review articles and personal contact with experts were used to identify studies. Studies were included if fetal echocardiography among unselected or low risk pregnant women was compared against a postnatal reference standard. Data were extracted on quality, study design and characteristics, and accuracy data to construct 2 x 2 tables. Data were synthesised qualitatively, and sensitivity and specificity with 95% confidence intervals were calculated.

MAIN OUTCOME MEASURE

Sensitivity and specificity.

RESULTS

Five primary studies met the inclusion criteria and comprised 60,901 subjects. One study assessed the accuracy of fetal echocardiography among an unselected population and four studies among low risk populations. All eligible studies found that fetal echocardiography helped to correctly diagnose normal fetus among unselected and low risk populations. Correct diagnosis of babies for congenital heart defects was higher among the unselected population (85%) than among the low risk populations (range from 35% to 86%); however, the potential for ascertainment bias and the choice of reference standard limits the validity of this finding. The variation in sensitivity across studies was not explainable by clinical factors such as scanning regime, operator skill and equipment.

CONCLUSIONS

The evidence from this review about the accuracy of fetal echocardiography does not lend support to its routine use among unselected and low risk populations during the second trimester to detect congenital heart disease.

Prenatal diagnosis of congenital heart disease in the Naples area during the years 1994-1999 -- the experience of a joint fetal-pediatric cardiology unit

OBJECTIVES

To analyse the spectrum and frequencies of observed malformations; to evaluate associated extracardiac and chromosomal anomalies and outcomes in each diagnostic category; to demonstrate the need for a multidisciplinary approach to the diagnosis of CHD in the fetus.

METHODS

From January 1994 to December 1999, 450 cases of CHD were detected among 4052 pregnancies at risk of fetal CHD seen at our combined unit. Confirmation of the diagnosis was not available in 50 cases, leaving 400 cases for analysis. From our computerized database, the following variables were retrieved and analysed: indication, gestational age at diagnosis, associated extracardiac anomalies, karyotype, natural history, pregnancy and feto-neonatal outcome.

RESULTS

CHDs most commonly detected were VSD (75 cases), AVSD (40 cases) and HLH (37 cases). The aneuploidy rate was 29.3% in the 355 cases submitted for karyotyping (25.9% in the whole series), with a prevalence of trisomy 21 and 18 (48 and 30 cases, respectively). The aneuploidy rate was highest for AVSD (80%), coarctation (49%), tetralogy of Fallot and VSD (45%). Associated extracardiac anomalies were present in 29.5% of the cases (118/400). As for pregnancy outcome, there were 150 (37.5%) terminations of pregnancy, 16 (4%) intrauterine fetal deaths and 85 (21.3%) neonatal deaths. The remaining 149 neonates are alive (37.3% survival rate). The termination rate for pregnancies in which CHD was detected at a gestational age <25 weeks was 65.2%. Evolutive changes determined progressive prognostic deterioration in 21 cases (5%), consisting of semilunar valve obstructions and development of ventricular hypoplasia.

CONCLUSIONS

The high association rate with extracardiac and chromosomal anomalies (29.3% and 25.9%) and the possible progressive prognostic deterioration require a multidisciplinary team for correct management and follow-up. Survival of fetuses with certain CHD is severely reduced, in comparison with postnatal figures, for the common association with aneuploidies.

The role of genetic counseling in the management of prenatally detected congenital heart defects

Genetic counseling should be used in the context of prenatal diagnosis of congenital heart defects for several reasons. The insight gathered through the family history, review of ultrasound findings, and chromosome analysis may help to determine the origin of the defect, such that more precise information about prognosis and recurrence risks can be given. This information should be used by the patient to consider options for the current pregnancy and management of future ones. The difficult and emotionally charged decisions that come with prenatal diagnosis of congenital heart defects demand that the psychosocial burden be explored with the patient. Genetic counseling should facilitate the decision-making process and address patient needs. Genetic counselors have the training, experience, and time to focus on these elements. The role of genetic counseling in congenital heart defects is likely to increase as advances in understanding the underlying genetic causes are made and incorporated into patient care and counseling. Genetic counseling for this indication will become more common as prenatal detection improves and as more affected individuals live to reproductive age.

The association between congenital heart disease and Down syndrome in prenatal life

OBJECTIVE

To assess the relationship between congenital heart disease (CHD) and Down syndrome (DS) in utero.

DESIGN

Retrospective case series.

SUBJECTS

Fifty-two fetuses with a cytogenetic diagnosis of DS managed at our Fetal Cardiology Unit in the study period. In particular, two populations of fetuses with DS were studied: a group of 41 DS fetuses referred to our unit for fetal echocardiography due to the chromosomal anomaly and a second group of 274 fetuses referred because of suspected CHD, 11 of which were found to have DS.

METHODS

All fetuses were submitted to detailed ultrasound evaluation of fetal anatomy. Associated extracardiac anomalies, and presence and type of CHD, were recorded for all fetuses. Karyotyping was obtained by means of cordocentesis or amniocentesis. Necropsy or neonatal echocardiograms were sought for confirmation of the prenatal diagnosis.

RESULTS

In the group of 41 fetuses with known DS, the incidence of CHD was 56% ([atrioventricular septal defect (AVSD) 44%, ventricular septal defect (VSD) 48%], the remainder having other heart defects). Conversely, considering the incidence of DS in fetuses with CHD, 43% of all AVSDs (53% of AVSD with normal visceral situs) were associated with DS, whereas none of the 39 cases of VSD was associated with trisomy 21. Ventricular septal defects were diagnosed only in fetuses referred to our center with a known diagnosis of aneuploidy.

CONCLUSIONS

We have confined that more than half of the fetuses with DS bear a CHD, which is an AVSD in 44% of cases. Conversely, 43% of fetuses with an AVSD have trisomy 21. For VSDS, the situation is controversial, due to the relatively low detection level of this heart defect at the routine mid-trimester obstetric scan.

Spectrum of congenital heart defects and extracardiac malformations associated with chromosomal abnormalities: results of a seven year necropsy study

OBJECTIVE

To analyse the spectrum of congenital heart malformations, the frequency of extracardiac malformations, and the proportion of chromosome aberrations among fetuses sent for necropsy.

MATERIAL

Necropsies were performed on 815 fetuses-448 induced abortions (55%), 220 spontaneous abortions (27%), and 147 stillbirths (18%)-during a seven year period (1991-97) in the department of pathology of the Charité Medical Centre in Berlin. A congenital heart defect was identified in 129 cases (16%). For all 129 fetuses, karyotyping and an ultrasound examination had been performed.

RESULTS

Congenital heart defects were present in 22% of induced abortions (99 cases), 9% of spontaneous abortions (20 cases), and 7% of stillbirths (10 cases). The heart malformations were classified into 13 categories. A fetus with more than one defect was included only in the category of the most serious defect. The malformations in order of frequency were: ventricular septal defect (VSD) (28%), atrioventricular septal defect (AVSD) (16%), hypoplastic left heart (HLH) (16%), double outlet right ventricle (DORV) (12%), coarctation of the aorta (CoA) (6%), transposition of the great arteries (TGA) (4%), aortic valve stenosis (AoVS) (4%), tetralogy of Fallot (TOF) (3%), truncus arteriosus communis (TAC) (3%), pulmonary valve stenosis/pulmonary valve atresia (PaVS/PaVA) (3%), tricuspid atresia (TA) (3%), single ventricle (SV) (1.5%), and atrial septal defect (ASD) (0.5%). The most common congenital heart defects were VSD, AVSD, HLH, and DORV, which made up 72% of all the cases. In 11 cases the heart defect was isolated (no other cardiovascular or extracardiac malformations present), 85 cases (66%) were associated with additional cardiac malformations, 85 cases (66%) were associated with extracardiac malformations, and chromosome anomalies were detected in 43 cases (33%).

CONCLUSIONS

Fetal congenital heart malformations are common. These defects are often associated with other cardiovascular and extracardiac malformations, as well as with chromosome anomalies. Complex heart defects such as AVSD, HLH, and DORV are frequent in fetuses, as they often lead to spontaneous abortion or stillbirth or, after prenatal diagnosis, to deliberate termination of pregnancy.

Ultrasound evaluation of the fetal heart: is it possible?

Ultrasound evaluation of the fetal heart can be performed. Knowledge of the embryology, anatomy, and function of the heart have led us to understand the pathophysiology of congenital heart disease. In this review we discuss the indications as well as some basic principles of fetal echocardiography.

Prognosis following prenatal diagnosis of heart malformations

Our objective was to document the prognosis of cases with fetal heart malformations (FHM). Forty-two fetuses assessed both in a regional fetal medicine and paediatric cardiology unit were classified prenatally into isolated FHM or those associated with extra-cardiac structural or karyotypic anomalies (ECA) and this classification was not changed subsequently (analogous to an intention to treat analysis). The end points studied included chromosomal abnormality, pregnancy outcome and follow-up at one year of age. FHM were isolated in 16 (38%) and associated with ECA in 26 (62%) of cases. The karyotypic abnormality rate was 8/42 (19%) overall and 8/26 (31%) in ECA cases. The pregnancy outcome included termination of pregnancy in 19 (45%), intrauterine death of two (5%) and live birth in 21 (50%). 12/16 (75%) of isolated FHM cases were live born compared with 9/26 (35%) of ECA cases (P < 0.03). Of the isolated FHM live born babies, 8/12 (67%) were alive at the end of the first year and seven of these were growing normally and did not require cardiac medication. However, a considerable proportion of their first year was spent in hospital (median 8%, interquartile range 5-10). Only one of nine ECA live born cases was alive but with poor growth and dependence on cardiac drugs at one year. These data confirm previous findings in prenatal diagnosis series that the prognosis for FHM is worse than that reported in studies of congenital heart disease at birth and is strongly dependent upon the presence of ECA. In their absence, outcome is better than previously published. Counselling must take place only after full fetal medicine assessment and should be based upon prenatal data.

Prenatal sonographic findings in 187 fetuses with Down syndrome

We determined the type and frequency of abnormal sonographic findings in 187 Down syndrome fetuses. Examinations were performed transvaginally or transabdominally between 9 and 28 weeks' gestation. Consecutive scans performed prior to knowledge of the fetal karyotype (n = 144) were analysed separately for one of the participating centres. In 93 fetuses (49.7 per cent), a total of 138 abnormalities were observed. The most commonly detected anomalies were cystic hygroma and increased nuchal fold thickness (30.5 per cent), hydrops (9.6 per cent), cardiac defects (7.5 per cent), pyelectasis or hydronephrosis (5.9 per cent), echogenic bowel (4.8 per cent), and a large variety of internal organ abnormalities (16.0 per cent) which are not typically associated with Down syndrome. Two anomalies or three anomalies in the same fetus were observed in 21 and 5 fetuses, respectively. No patterns of concurrent malformations were apparent among these fetuses. Sensitivity for Down syndrome detection by ultrasound scans performed without knowledge of the fetal karyotype was 24.1 and 42.6 per cent before 13 weeks and between 14 and 23 weeks, respectively. We conclude that structural abnormalities are frequently observed in Down syndrome fetuses, but many sonographic findings are not typically associated with this syndrome.

Efficacy of routine fetal ultrasound screening for congenital heart disease in normal pregnancy

BACKGROUND

Second trimester routine ultrasound evaluation of the fetal heart by means of the four-chamber view has been proposed for prenatal detection of cardiac anomalies. The aim of this study was to evaluate the efficacy of this procedure.

METHODS AND RESULTS

A prospective follow-up study on 6922 scanned fetuses was performed. Pregnant women without known risk factors who were scheduled for a routine fetal ultrasound examination between 16 and 24 weeks gestation were invited to participate. Follow-up until 6 months postpartum was available for 5660 subjects (81.8%), of whom 5319 fulfilled all eligibility criteria. by comparing the prenatal diagnosis to the postnatal diagnosis, we obtained sensitivity, specificity, and predictive value (positive and negative). A total of 80 cases of congenital malformations were diagnosed during the study: 44 cases of congenital heart disease, 40 cases of noncardiac malformations, and a combination of the two in 4 cases. The fetal four chamber-view examination was considered abnormal in 7 women who were subsequently referred for extensive fetal ultrasound examination. Two proved to be carrying an affected fetus. Similarly, prenatal referral of 14 women because of suspected noncardiac malformations yielded 12 such cases. The fetal four chamber-view examination had a sensitivity of 4.5% (95% CI, 0.6% to 15%). Sensitivity for noncardiac anomalies was 30% (95% CI, 16.6% to 46.5%). Overall sensitivity of ultrasound examination was 16.3% (95% CI, 2.09% to 48.8%). Specificity and negative predictive value were high (>98%). The positive predictive value was low with wide CIs.

CONCLUSIONS

These results suggest that the current mode of routine prenatal ultrasound screening for congenital malformations is inefficient, particularly for cardiac anomalies.

Prenatal diagnosis of congenital heart disease; prospects and problems

Routine fetal echocardiography has been submitted as an antenatal screening test for congenital heart disease despite a wide range of efficacy reported. Hence, evaluation of the variable results of prenatal ultrasound screening programs was pursued. As the studies appeared to have a heterogeneous design, the originally reported figures have been corrected for one plausible prevalence of cardiovascular anomalies. Clinical setting (general hospitals vs. teaching hospitals), case ascertainment (retrospective vs. prospective; follow-up on (suspected) cases only vs. routine follow-up) and length of follow-up (< 1 year vs. a longer period) all have similar effects on the reported yield of cases and sensitivity of the proposed screening test. Notably, a relatively low yield of cases causes a seemingly high sensitivity, whereas a higher yield of cases causes a seemingly low sensitivity. Additional factors of study design, e.g. case definition, diagnostic procedures and appliances used, were usually not described in detail, yet may also have affected the results. Evaluating diagnostic tests apparently demands a rigorous study design to overcome biased results. Furthermore, no sufficient evidence could be found meriting current routine prenatal screening for congenital heart disease.

Ultrasonographic fetal iliac length measurement in the screening for Down syndrome

OBJECTIVE

Pelvic bone abnormalities are common in newborns with Down syndrome. The aim of this study was to evaluate the utility of ultrasonographic iliac bone length measurement in the identification of fetuses with Down syndrome in the second trimester of gestation.

STUDY DESIGN

Ultrasonographic iliac length measurement was obtained, in an axial view of the fetal pelvis, on 10 fetuses with Down syndrome and 180 karyotypically normal fetuses before genetic amniocentesis. Regression equations relating biparietal diameter to iliac length measurement were used to calculate ratios of observed-to-expected length, sensitivity, and specificity at various cutoff points.

RESULTS

Linear regression of iliac length measurement on biparietal diameter for normal fetuses resulted in the following equation: iliac length measurement (centimeters) = -0.2723 + 0.0333 biparietal diameter (millimeters). Iliac length measurement in Down syndrome fetuses was significantly longer than in normal controls (p < 0.0001). A ratio of 1.21 for observed-to-expected iliac length measurement yielded a sensitivity of 40%, a specificity of 98%, and positive predictive values of 50% and 2.60%, respectively, in populations at risk for Down syndrome of 1 in 20 and 1 in 750.

CONCLUSION

Iliac length measurement is increased in fetuses with Down syndrome. An observed-to-expected iliac length measurement of > or = 1.21 has a positive predictive value of 1/38 in a low-risk population with a false-positive rate of 2%. This preliminary study suggests that iliac length measurement may be useful as an ancillary screening variable in antenatal screening for Down syndrome.

True trisomy 15 mosaicism, detected by amniocentesis at 12 weeks of gestation and fetal echocardiography

A case of mosaicism of trisomy 15, with two-thirds of the cells trisomic, was detected at 12 weeks of gestation in amniotic fluid cell cultures obtained with the filtration technique. Ultrasound examination at 13 weeks showed a nodule protruding into the amniotic cavity which was speculated to be remnants of a co-twin, causing the trisomic cell line. At 20 weeks of gestation, a malformation scan (level III) was normal, but supplementary fetal echocardiography revealed a severe cardiac defect (mitral atresia and a ventricular septal defect). Fetal lymphocytes obtained by cordocentesis showed trisomy 15 mosaicism, but only in 5 per cent of the mitoses. After termination, the same percentage of trisomy 15 mosaicism was found in cells from skin and tendon as in the original early amniocentesis. No sign of earlier twinning was found in the placenta or membranes. We conclude that mosaicism in early amniotic fluid obtained by the filter technique in this case reflected the true karyotype accurately and that supplementary echocardiography added significantly to the interpretation of the clinical implications.

Coarctation of the aorta: difficulties in prenatal diagnosis

OBJECTIVE

To formulate echocardiographic criteria for the prenatal diagnosis of coarctation of the aorta.

DESIGN

A retrospective study examining the echocardiograms of fetuses with a verified aortic arch abnormality and those in whom the diagnosis was suspected prenatally but was not subsequently confirmed.

SETTING

Tertiary referral centre for fetal echocardiography.

PATIENTS

87 fetuses in whom the diagnosis of coarctation was correctly made in 54, suspected but unproved in 24, and overlooked prenatally in nine.

MAIN OUTCOME MEASURES

Measurements of left and right ventricular size, the diameters of the great arteries, the diameters of the left and right atrioventricular valvar orifices, the appearance of the aortic arch, and the direction of the flow of blood across the foramen ovale.

RESULTS

Measurements of the ventricular widths, diameters of the great arteries, or the diameters of the atrioventricular valvar orifices, did not allow clear distinction between cases that definitely had a coarctation and those in whom the diagnosis was unproved. The appearance of the aortic arch, particularly in the horizontal projection, was more helpful in distinguishing cases of coarctation, although this also was not always diagnostic. A predominantly left to right shunt across the foramen ovale was detected more often in cases with a substantiated coarctation (58%) than in those with an unproved diagnosis (12%).

CONCLUSIONS

The most severe forms of coarctation are associated with relative hypoplasia of the left heart structures compared with the right and a correct diagnosis can be made in early pregnancy. The milder forms of coarctation, however, are consistent with a normal early fetal echocardiogram. In late pregnancy it may be impossible to exclude coarctation categorically as the right heart structures may appear larger than the left in the normal fetus. Thus although a combination of echocardiographic features can correctly identify aortic arch anomalies in the fetus, none either alone or in combination, could clearly distinguish between real and false positive cases, particularly in late gestation.

Transabdominal chorionic villus sampling in the second and third trimesters of pregnancy: chromosome quality, reporting time, and feto-maternal bleeding

Transabdominal chorionic villus sampling (TA-CVS) was performed in 210 pregnancies from 13 to 38 weeks using a double-needle technique. The sampling success was comparable to first-trimester TA-CVS and the diagnostic success rate was 98.2 per cent for the short-term technique and 99.3 per cent for cultured villi. Two fetuses could not be karyotyped. We found the chromosome quality to be similar to that in the first trimester, comparing the number of G-bands and other chromosome attributes. There were no unintended losses in a group (n = 142) with no sonographic abnormality, except for one death in utero at 38 weeks, 20 weeks after sampling. Chromosomal aberrations were seen in 19 per cent of cases with abnormal sonograms (n = 58). One cases of a discordant karyotype was found (false-negative prediction of Down's syndrome by the short-term preparation). There were no cases of fetal demise due to feto-maternal bleeding. It is suggested that double-needle TA-CVS in advanced pregnancies combines the advantages of rapid karyotyping of chromosomes of good quality and low risk for the fetus, and seems to be easier to practise and is probably safer than cordocentesis.

The ultrasound markers of chromosomal disease: a retrospective study

Over a 3 year period 37 pregnancies were complicated by a chromosomal abnormality. In the two cases of trisomy 13, holoprosencephaly, facial clefting, polydactyly and growth retardation were seen. In the seven cases of trisomy 18, abnormalities of the extremities, face and heart were common. Growth retardation and diaphragmatic hernia were also demonstrated. In the 21 cases of Down's syndrome the main abnormalities were cardiac, duodenal atresia and subtle digital anomalies. The two fetuses with triploidy showed a large hydropic placenta and holoprosencephaly respectively, and all five cases of Turner's syndrome demonstrated a cystic hygroma two of which were associated with hydrops. From the antenatal scans major anomalies were detected in 18 fetuses, however, chromosomal disease was suspected in only 15 cases. This was in part owing to a high false negative rate for cardiac anomalies (14 cases) in both routine and detailed scans. Owing to the diversity of anomalies present in chromosomal disease full assessment of the fetus is recommended with particular attention to the fetal heart, face, hands and feet. Specific anomalies are suggested for karyotype.

Outcome of prenatally detected cardiac malformations

Reliable, prenatal detection of congenital heart disease has become possible over the past decade with the evolution of fetal echocardiography. We have documented the outcome of 170 cardiac defects diagnosed prenatally since 1984. Of 170 cases, 55 (32%) had major extracardiac malformations and 45 (28%) chromosomal abnormalities (16 had both). Elective termination was chosen in 77 (45%) pregnancies. Of 93 continuing pregnancies 15 were stillborn and 43 died postnatally (48% of these fetuses and infants had extracardiac or chromosomal anomalies, or both). Thirty-five patients survive at 1 to 80 months (mean 36). Aneuploidy or extracardiac defects are present in 20% of survivors. Nonimmune hydrops secondary to cardiac failure was present in 7 continuing pregnancies and none of these patients survived. The prognosis of prenatally diagnosed cardiac lesions is negatively influenced by the presence of cardiac failure, aneuploidy or extracardiac malformations, or a combination of these. Optimal counseling and management requires the identification of these conditions when present.

Fetal humeral length to detect Down syndrome

OBJECTIVE

Our aim was to evaluate the utility of ultrasonographic humeral length measurements for detection of fetuses with Down syndrome in the midtrimester of gestation.

STUDY DESIGN

Ultrasonographic biometry data obtained before genetic amniocenteses on 43 fetuses with Down syndrome and 204 randomly chosen normal fetuses were analyzed. Regression equations relating biparietal diameter to humeral length and femoral length were used to calculate ratios of observed-to-expected length and sensitivity and specificity at various cutoff points.

RESULTS

Humeral length in Down syndrome fetuses was significantly shorter than in normal controls (p less than 0.001). A ratio of 0.90 for observed/expected humeral length yielded a sensitivity of 28%, a specificity of 91%, and positive predictive values of 1.23% and 0.41% in populations at risk for Down syndrome of 1 in 250 and 1 in 750, respectively. The equivalent ratio for femoral length yielded a sensitivity of 19%, a specificity of 91%, and positive predictive values of 0.87% and 0.28% for baseline risks of 1 in 250 and 1 in 750, respectively.

CONCLUSIONS

The sensitivity of fetal humeral length measurements for Down syndrome detection in our hands was remarkably lower than previously reported. Independence of this parameter from currently used serum screening markers has not been established; therefore implementation in screening programs is not advisable at this point.

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.

Hypoplastic left heart syndrome: prenatal diagnosis, clinical profile, and management

We diagnosed hypoplastic left heart syndrome, generally regarded as a lethal congenital heart defect, by fetal echocardiography in 20 pregnancies in the last 5 years. The clinical profile, management, and outcome of these pregnancies were reviewed. We found a 40% association of karyotype and extracardiac malformations. Elective abortion was performed in nine pregnancies. Two of seven live-born babies had early neonatal assessment and intervention as a result of in utero diagnosis and counseling. Prolonged survival was achieved in both infants. We conclude that prenatal diagnosis of the hypoplastic left heart syndrome necessitates complete evaluation of the fetus for associated genetic and extracardiac malformations. Prenatal diagnosis of this defect provides opportunities for in depth counseling of parents and obtaining informed consent for either postnatal intervention or nonintervention before the medical and emotional complexities associated with the neonatal intensive care setting are encountered.

Ultrasound diagnosis of fetal abnormalities and cytogenetic evaluation

Over a 6 1/2 year period, in 288 pregnancies a variety of fetal malformations were detected by ultrasound. Two hundred and ten fetuses (73 per cent) were karyotyped. Gestational age at detection ranged from 11 to 38 weeks. The incidence of an abnormal karyotype in the total series was 14 per cent and 14.7 per cent in the 210 pregnancies in which a karyotype was performed. Single structural anomalies were found in 149 cytogenetically investigated fetuses, of which 25 had a chromosomal abnormality (17 per cent). Multiple structural malformations were present in 61 fetuses, of which 16 had an abnormal karyotype (26 per cent). Trisomy 18 was the most frequent finding. The most constant ultrasound finding in cases of an abnormal karyotype was polyhydramnios and severe IUGR in combination with structural defects. There is a need for extensive detailed ultrasound examination in high-risk pregnancies.

Ultrasonographic screening for the Down syndrome fetus

The usefulness of ultrasonography in detecting fetuses with Down syndrome in the second trimester has been the subject of considerable debate during the past 3 years. Conflicting reports have led to increasing confusion about the subject in the medical community and among the public. A review of the existing literature indicates that structural malformations that are chiefly cardiac are present in half of Down syndrome fetuses but are not consistently found during routine second-trimester ultrasonography. Although excess posterior nuchal skin-fold thickness is frequently present in infants with Down syndrome, it is also not consistently identified during second-trimester ultrasonographic examinations. Studies evaluating the efficacy of screening programs that are based on femur length shortening associated with Down syndrome have revealed markedly discrepant intercenter results. Although variations in methods may account for some of the observed variability, the magnitude of femoral shortening in Down syndrome suggests that this measurement may be only marginally useful. In summary, antenatal ultrasonography will allow for the detection of only those fetuses with Down syndrome who have multiple characteristic phenotypic features or anomalies. Moreover, current second-trimester ultrasonography does not appear to be either sensitive enough specific enough to be used as a unique Down syndrome screening modality; however, it may be a useful adjunct to maternal age and serum biochemical markers in the assignment of risk for Down syndrome.

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.

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.

Echocardiographic evaluation of the spectrum of cardiac anomalies associated with trisomy 13 and trisomy 18

To investigate the role that cardiac anomalies play in the early death frequently seen in the trisomy 13 and the trisomy 18 syndromes, two-dimensional and Doppler echocardiograms from 31 newborn infants with cytogenetic confirmation of these syndromes seen at one institution over a 4.5 year period (1983 to 1988) were reviewed. The mean age at echocardiography was 1.5 days, and the median age at death was 14 days. Significant cyanosis was present in 58%. Cardiac anomalies that would be considered lethal within the neonatal period were present in only 19% of patients. The most common lesions were atrial septal defect (81%), ventricular septal defect (61%) and patent ductus arteriosus (85%). Most ventricular septal defects and patent ductus arteriosus were large. Valvular dysplasia of one or more valves, graded as mild in most cases, was found in 68%, but was not associated with Doppler evidence of significant regurgitation or stenosis in any subject. Of the four valves, the pulmonary valve, followed by the tricuspid valve, was the most commonly dysplastic. Doppler evidence suggestive of elevated pulmonary artery pressure (low velocity bidirectional flow across the ventricular septal defect and patent ductus arteriosus), although expected, was accompanied by greater than normal mean right ventricular cavity and free wall dimensions in these patients. Thus, although the cardiac anomalies most frequently encountered in trisomy 13 and trisomy 18 are nonlethal, the combined findings of frequent cyanosis and increased right ventricular dimensions suggest that other factors such as pulmonary hypertension, perhaps related to maldevelopment of the pulmonary vasculature, may contribute to early death in some of these infants.

Cardiac and extra-cardiac anomalies as indicators for trisomies 13 and 18: a prenatal ultrasound study

The purpose of the present study was to establish sonographic markers for prenatal diagnosis of trisomies 13 and 18. Retrospective analysis of sonographic morphology was therefore carried out in seven fetuses with trisomy 13, and 16 fetuses with trisomy 18. Gestational age ranged between 17 and 39 weeks (median 28 weeks). Polyhydramnios and symmetrical growth retardation were present in 14 of 23 fetuses. A cardiac anomaly was diagnosed in all 23 fetuses, the majority representing a ventricular septal defect (n = 8) or double outlet right ventricle (n = 8). Extra-cardiac anomalies were characterized by a high incidence of limb deformities (polydactyly, clenched hands, club feet; n = 15) and omphalocele (n = 7). We conclude that the combined appearance of cardiac and extra-cardiac anomalies should prompt fetal karyotyping. Cardiac anomalies in combination with fetal limb deformities and omphalocele are suspicious for trisomies 13 and 18.