Aberrant right subclavian artery at 11 + 0 to 13 + 6 weeks of gestation in chromosomally normal and abnormal fetuses

The "full rectangle" sign: a novel method for ultrasonographic diagnosis of fetal aberrant right subclavian artery

OBJECTIVE

To evaluate the feasibility and accuracy of a novel ultrasonographic screening method for an aberrant right subclavian artery (ARSA) using the novel "full rectangle" method.

METHODS

This prospective study was conducted at a tertiary care center, September 2022 to February 2023. The study included unselected pregnant women at 14-38 weeks of gestation referred for routine or targeted anomaly scans. All participants underwent scanning by two experienced sonographers to ascertain the presence or absence of aberrant right subclavian artery (ARSA) using both conventional and novel "full rectangle sign" methods for validation purposes. This is a novel screening method for ARSA that demonstrates the retro-tracheal course at the level of the supra-aortic vessels, forming what we term the "full rectangle sign".

RESULTS

A cohort of 138 patients was enrolled. The "full rectangle" sign was discerned in 6 fetuses with ARSA (4.3%), while the typical three-sided figure of the right subclavian artery was demonstrated in the remaining 132 fetuses (95.7%). The novel method demonstrated 100% feasibility and complete concordance with the conventional method.

CONCLUSION

The study results indicate that the full rectangle sign serves as an effective and dependable screening tool for identifying ARSA. It offers the advantage of a clear, unobstructed view at a level unaffected by sternum shadowing and eliminates confusion with the azygous vein.

Aberrant right subclavian artery: the importance of distinguishing between isolated and non-isolated cases in prenatal diagnosis and clinical management

OBJECTIVES

This study aimed to evaluate the association of aberrant right subclavian artery (ARSA) with genetic abnormalities and postnatal symptomatology, by comparing isolated and non-isolated ARSA cases.

METHODS

Retrospective, descriptive and comparative study involving fetuses diagnosed with ARSA during routine fetal ultrasound scans, between 19 and 40 weeks, in a tertiary referral university hospital in Barcelona from January 2007 to December 2023.

RESULTS

Out of 154 fetuses diagnosed with ARSA, 75.3 % (116) were classified as isolated cases, while 24.7 % (38) had associated structural anomalies. Non-invasive prenatal testing with cell-free DNA was performed in 27.3 % (42) of cases, yielding low-risk results in 96.6 %, with only one case of trisomy 21 detected. Genetic evaluation was pursued in 15.6 % (24) of cases, revealing abnormalities in three fetuses: one with trisomy 21 and two with 22q11 deletion. All affected fetuses had associated structural defects. Overall, 151 fetuses survived after birth, there were two terminations of pregnancy and one stillbirth. Mild symptoms at birth were observed in 1.9 % (3) of newborns, all from the non-isolated ARSA group.

CONCLUSIONS

These findings emphasize the significance of distinguishing between isolated and non-isolated ARSA cases in prenatal diagnosis and clinical management, suggesting that isolated ARSA may be considered a normal vascular variation.

Postnatal outcome of fetal aberrant right subclavian artery: a single center study

PURPOSE

This study aims to explore the correlation between fetal aberrant right subclavian artery (ARSA) and chromosomal disorders, with a specific focus on Down syndrome and DiGeorge syndrome.

METHODS

From November 2017 to February 2020, we conducted fetal anomaly screening and assessed the fetal heart in 8494 at our institution. The right subclavian artery tracing was assessed using Doppler ultrasonography following the 3-vessel and tracheal views (3VTV) in the fetal heart scan.

RESULTS

ARSA was found in 31 fetuses, which accounts for 0.36% of the total of 8494 fetuses. 96.8% of fetuses with ARSA were found to have normal chromosomal analysis. We identified only one case of trisomy 21 as the chromosomal condition present. In 80% of the identified ARSA, there were no additional associated findings.

CONCLUSION

ARSA is a rare condition that often does not manifest any concomitant abnormalities. The majority of ARSA instances identified in the second trimester are euploid. If ARSA is the only sonographic finding during fetal anomaly screening and there are no maternal or laboratory risk factors, further evaluation with non-invasive diagnostics may be recommended. Non-invasive genetic testing may be used for additional investigation.

Associated congenital anomalies and genetic anomalies in fetuses with isolated and non-isolated aberrant right subclavian artery

OBJECTIVE

This study's aim was to determine the prevalence of chromosomal anomalies in fetuses with isolated and non-isolated aberrant right subclavian artery (ARSA) and to evaluate its association with other congenital anomalies.

METHODS

From September 2018 to October 2021, 668 ARSA cases were diagnosed by prenatal ultrasound in our hospital; cases with missed visits and a lack of chromosomal findings were excluded and 363 cases were eligible for enrollment. General information, ultrasound presentation, chromosomal findings and pregnancy outcomes were retrospectively analyzed.

RESULTS

Among the 363 cases, 296 were isolated, and 67 were associated with structural abnormalities or soft marker abnormalities. The proportion of fetuses with chromosomal abnormalities in the isolated ARSA group was significantly lower than that in the non-isolated ARSA group (p < .001). In the non-isolated ARSA group, 22 cases were combined with other soft marker abnormalities and 45 cases were combined with structural abnormalities. The most frequent structural abnormality coexisting with ARSA was cardiac malformations (38.81%).

CONCLUSION

The most common combined malformation in ARSA is intracardiac malformation. Isolated ARSA has a low risk of chromosomal abnormalities, so invasive chromosomal testing is not recommended. Non-isolated ARSA has a high incidence of chromosomal abnormalities, so early karyotyping should be recommended.

Prenatal genetic analysis of fetal aberrant right subclavian artery with or without additional ultrasound anomalies in a third level referral center

To evaluate the correlation between chromosomal abnormalities and fetal aberrant right subclavian artery (ARSA) with or without additional ultrasound anomalies (UAs). A total of 340 fetuses diagnosed with ARSA by ultrasound between December, 2015, and July, 2021, were included. All cases were subdivided into three groups: (A) 121 (35.6%) cases with isolated ARSA, (B) 91 (26.8%) cases with soft markers, and (C) 128 (37.6%) cases complicated with other UAs. Invasive testing was performed via amniotic fluid or cord blood karyotyping and chromosomal microarray analysis (CMA) in parallel, and pregnancy outcomes were followed. Karyotype abnormalities were identified in 18/340 (5.3%) patients. Karyotype abnormalities in Groups A, B, and C were 0/121 (0.0%), 7/91 (7.7%), and 11/128 (8.6%), respectively. CMA abnormalities with clinically significant variants were detected in 37/340 (10.9%) cases, of which 22q11.2 deletion syndrome and trisomy 21 accounted for 48.6% (18/37). The overall abnormal CMA with clinically significant variant detection rates in Groups A, B, and C were 3/121(2.5%), 13/91 (14.3%), and 21/128 (16.4%), respectively. There were significant difference in clinically significant CMA anomalies detection rate between Groups A and C (p < 0.05), as well as Groups A and B (p < 0.05). Comparing CMA to karyotyping showed a clinically significant incremental yield in Group C (7.8%, 10/128) compared to Groups A (2.5%, 3/121) and B (6.6%, 6/91) (p > 0.05). Fetal ARSA with additional UAs, concurred with cardiac and extra-cardiac anomalies, constitutes a high-risk factor for chromosomal aberrations, especially for pathogenic or likely pathogenic copy number variants.

Aberrant right subclavian artery: embryology, prenatal diagnosis and clinical significance

Introduction

The right subclavian artery normally arises as the first vessel from the brachiocephalic trunk. An aberrant right subclavian artery (ARSA) arises directly from the aortic arch and crosses behind the trachea towards the right arm. This variant occurs in approximately 1-2% of the population; however, the frequency increases in individuals with chromosomal abnormalities such as trisomy 21 and 22q11.2 microdeletion. Prenatal identification of ARSA therefore has a role in screening for such conditions.

Methods

Databases were searched for studies reporting the prenatal ultrasound evaluation of ARSA and its frequency in normal fetuses and in those with chromosomal abnormalities.

Results

A total of 23 studies were evaluated. Feasibility for the ultrasound evaluation of ARSA was 85-95%. The sonographic detection of ARSA is best in the three-vessel trachea view; however, sagittal and coronal imaging of the aortic arch may be useful. ARSA in isolation was not found to be associated with chromosomal abnormalities. The prevalence of ARSA in chromosomally abnormal fetuses was up to 24-fold higher than in normal fetuses, but the majority of chromosomally abnormal fetuses with ARSA had additional abnormal ultrasound findings, particularly cardiac abnormalities.

Conclusions

The prenatal detection of ARSA is a clinically useful prenatal marker for chromosomal abnormalities. In isolation, it is unlikely to be associated with pathogenic genetic variants. The ultrasound diagnosis of ARSA should prompt meticulous assessment of associated abnormalities. Invasive diagnostic testing should be offered to patients with non-isolated ARSA or in the presence of non-reassuring screening results or other risk factors.

Identification of Novel Compound Heterozygous Variants of MMP9 in Fetus With Metaphyseal Anadysplasia Type 2

Matrix metalloproteinase 9 (MMP9) is an important member of the matrix metalloproteinase family and plays a key role in balancing extracellular matrix proteins. Studies have shown that the homozygous mutations in MMP9 can lead to metaphyseal anadysplasia type 2 (MANDP2, OMIM#613073). The clinical phenotype of this disease is limited and there were only five reported cases of MANDP2 associated with homozygous MMP9 mutations from three families. In this study, we described a case of a fetus with skeletal system malformation. The main clinical manifestations include the short bilateral femur, absence of right fibula, and curved ipsilateral tibia with short length. Importantly, two novel compound heterozygous variants of the MMP9 gene (NM_004,994.3: c.151C &gt; T and c.929del) were found through the trio whole exome sequencing and Sanger sequencing. This is the first report that identified the compound heterozygous variants of the MMP9 gene associated with metaphyseal dysplasia type 2.

Prenatal diagnosis of aberrant right subclavian artery: a literature review

The primary aim of this review is to estimate the prevalence of ARSA both in euploid fetuses as well as in fetuses with Down Syndrome. Secondary objectives were to estimate the association of ARSA with cardiac anomalies and chromosomal defects, especially trisomy 21 and 22q11 deletion (DiGeorge Syndrome). The incidence of ARSA in normal population varies from 0.35% to 3.5%, based on different studies. Since the first reported association between ARSA and trisomy 21 in 2015 until today, several studies have emerged to confirm different degrees of this correlation. Indeed, ARSA appears to be a clinically useful prenatal ultrasound marker for trisomy 21. Particularly, most recent studies concluded that ARSA as a non-isolated finding can be used as screening for Down syndrome. However, when ARSA is an isolated finding, various studies proved that there is no significant correlation with Down syndrome. Apart from these, ARSA appears to be associated with other chromosomal abnormalities, such as 22q11 deletion, cardiac defects and other morphological anomalies. As a conclusion ARSA should be characterized as isolated or non-isolated, as the non - isolated ARSA appears to be a clinically useful marker of Down syndrome and thus, additional testing is required when diagnosed.

Aberrant right subclavian artery as soft marker in the diagnosis of trisomy 21 during the first trimester of pregnancy

Purpose

Aberrant right subclavian artery is an anatomical variation with a prevalence of around 0.5–1.5% of the general population, being more frequently found among people with chromosomopathies, especially, trisomy 21. Despite being an anatomical finding, and thus, constant through the whole pregnancy, its value in the diagnosis of aneuploidies during the first trimester of pregnancy has been little studied. The aim of this study is to evaluate the reliability of the first-trimester ultrasound in the diagnosis of ARSA and its utility in the early diagnosis of aneuploidies.

Methods

This was a descriptive, observational, cross-sectional study that included all fetuses with sonographic diagnosis of ARSA between 2011 and 2018.

Results

There were 257 cases of ARSA diagnosed. The first-trimester ultrasound showed the following results in the detection of ARSA: sensitivity of 68% (CI 95% 60.8%–74.5%), specificity of 99.9% (CI 95% 99.9%–100%), positive predictive value of 93.7% (CI 95% 88.1%–96.8%), and negative predictive value of 99.6% (CI 95% 99.5%–99.7%). Due to the presence of ARSA, two cases of trisomy 21, that would have been missed in the first trimester, were diagnosed, using ARSA as a soft marker and modifying the risk obtained by the combined screening as part of the genetic sonogram of the first trimester.

Conclusions

ARSA visualization during the first-trimester ultrasound is trustworthy and it can improve the detection of trisomy 21 in some cases of aneuploidy missed during the combined screening of the first trimester.

Should isolated aberrant right subclavian artery be ignored in the antenatal period? A management dilemma

Objective:

To investigate the frequency and types of chromosomal abnormalities in fetuses with the aberrant right subclavian artery (ARSA) and to evaluate its association with other ultrasonographic findings.

Materials and Methods:

In all, 11,666 fetal anatomic surveys were performed between March 2014 and March 2020. The cases diagnosed as ARSA were examined. Accompanying ultrasound findings and chromosomal abnormalities were collected.

Results:

ARSA was detected in 140 fetuses (1.2%). The ARSA appeared isolated in 47.1% (66/140) of cases and the remaining 52.9% (74/140) of cases were associated with cardiac or extracardiac malformations and soft markers. Chromosomal abnormalities were detected in 17.8% (25/140) of all cases. Trisomy 21 was the most common chromosomal anomaly with a prevalence of 11.4% (16/140). The corresponding rate was 3% (2/66) and 18.9% (14/74) for isolated and non-isolated ARSA, respectively. DiGeorge syndrome was detected in 3% (n=2) and Turner syndrome was in 3% (n=2) of the isolated group. ARSA was not an isolated finding in any of the 4 fetuses with trisomy 18.

Conclusion:

Isolated ARSA may be the only antenatal predictor of trisomy 21 or other chromosomal anomalies, including DiGeorge or Turner syndrome. Hence, visualization of the right subclavian artery should be a part of the fetal anatomic survey and genetic analysis should be recommended even in the absence of associated findings.

Aberrant right subclavian artery: the association with chromosomal defects and the related post-natal outcomes in a third level referral centre

Aberrant right subclavian artery (ARSA) is the most common embryologic abnormality of the aortic arch. The presence of ARSA has been previously associated with an increased risk of Down syndrome. ARSA at birth may be associated with dysphagia, respiratory distress and stridor and there is no clear evidence-based management. The aim of this study was to describe the associations with chromosomal abnormalities and the postnatal outcome of fetuses diagnosed with ARSA. We analysed fetuses diagnosed antenatally with ARSA between January 2013 and September 2019 in the fetal echocardiography unit of the Hospital Monaldi, University 'Vanvitelli' of Naples, Italy. The results showed fifty fetuses diagnosed with ARSA, all confirmed after birth. The ARSA was an isolated finding in 46 fetuses (92%), while in 4 fetuses the ARSA was associated with other cardiac and/or extra-cardiac anomalies. Only one fetus was diagnosed with trisomy 21 (2%). In this fetus the ARSA was the only ultrasound anomaly identified. There were no cases necessitating referral due to the presence of compression symptoms at birth. The presence of ARSA was associated with trisomy 21 in the 2% of cases in our series and there were no neonatal complications due to airway compression at birth.IMPACT STATEMENTWhat is already known on this subject? Aberrant right subclavian artery (ARSA) is the most common embryologic abnormality of the aortich arch. ARSA at birth could be associated with dysphagia, respiratory distress and stridor and no evidence-based management of these fetuses has been described yet. The presence of ARSA has been previously associated with an increased risk of Down syndrome.What do the results of this study add? This study confirms known data on association with chromosomal defects and provides some original data on the absence of symptomatology due to tracheal compression with a postnatal follow-up up to three years of age.What are the implications of these findings for clinical practice and/or further research? Our findings suggest that in cases with adequate prenatal assessment performed by experienced clinicians, delivery can safely take place at local hospitals, with no need of referral soon after birth. The use of transthoracic echocardiography to confirm the diagnoses of ARSA after birth and to plan the next follow-up appointments can be supported.

PRENATAL IDENTIFICATION OF ABERRANT RIGHT SUBCLAVIAN ARTERY IN ISOLATION: THE NEED FOR FURTHER GENETIC WORK-UP?

The objective of this study was to evaluate the association between aberrant right subclavian artery (ARSA) and chromosomal abnormalities. The study included 5211 women having attended our unit for fetal anatomic screening and fetal echocardiography from August 2016 until February 2019. After diagnosing ARSA, prenatal invasive testing was discussed with the patients. ARSA affected fetus was determined in 57 cases; of these, there were 38 cases of isolated ARSA and 19 cases of non-isolated ARSA but associated with soft markers and fetal anomalies. Nineteen patients underwent amniocentesis; Down syndrome was determined in two women, both of them from the non-isolated ARSA group, with fetal hydrops, atrioventricular septal defect and esophageal atresia. Fifteen of 38 patients who declined prenatal diagnostic testing, accepted karyotype analysis after delivery and none of these 15 cases had chromosomal abnormalities. Identification of ARSA should be followed by detailed ultrasound examination to ensure that there are no accompanying soft markers and/or structural defects. Isolated ARSA may not be an indication for karyotype analysis or 22q11.2 microdeletions. Non-ARSA implies a strong predictor of aneuploidy, and when additional findings are detected, invasive testing should be offered to the parents. The association between isolated ARSA and genetic disease should be evaluated in large powered prospective studies.

Is it useful to evaluate the presence of aberrant right subclavian artery in prenatal diagnosis ultrasounds?

AIM

Analyze if the evaluation of aberrant right subclavian artery in the prenatal echography has improved the detection of chromosomal, genetic and/or morphological abnormalities in our population.

METHODS

Descriptive, observational, cross-sectional study of the cases of aberrant right subclavian artery diagnosed in our Prenatal Diagnosis Unit between January of 2011 and December of 2018.

RESULTS

Two hundred and fifty-seven cases of aberrant right subclavian artery were diagnosed and among them, 179 were considered isolated cases and thus were confirmed after birth. The detection of aberrant right subclavian artery did not improve itself neither the diagnosis of trisomy 21 in the second trimester of pregnancy nor other chromosomal or genetic abnormalities, including the not isolated cases. There were two cases of trisomy 21 diagnosed in the second trimester that presented major sonographic disorders and an inadequate examination during the first trimester. When aberrant right subclavian artery was associated with soft markers of aneuploidy in the second trimester, any case was a trisomy 21. Aberrant right subclavian artery seems to be associated with some minor and major heart defects, especially ventriculoseptal defect and aneurismatic ductus, and in some cases, also with clubfeet.

CONCLUSION

When an adequate screening of aneuploidies and a thorough ultrasound have been performed during the first trimester, aberrant right subclavian artery hardly helps to perform other diagnosis in the second trimester.

The “No ARSA” Sign: A Novel Method of Prenatal Screening for Aberrant Right Subclavian Artery

An aberrant right subclavian artery (ARSA) can be overlooked by the conventional method as described by Chaoui et al., due to acoustic shadowing. The aim of this study was to evaluate the feasibility and accuracy of a novel screening method for ARSA by demonstrating the brachiocephalic artery bifurcation, referred to as the “No ARSA” sign. A prospective study conducted at a tertiary care center between 2018 and 2019 included unselected pregnant patients at a median gestational age of 15.1 (14.2–22.1; IQR (inter-quartile range)) weeks, who had been referred for a routine or targeted anomaly scan. All participants were scanned for the presence or absence of ARSA using both the conventional and the novel “No ARSA” methods for validation purposes. A total of 226 unselected patients were enrolled in the study. The “No ARSA” sign was visualized in 218 fetuses (96.5%). In the remaining 8 cases (3.5%), the “No ARSA” sign was not demonstrated. In these fetuses, an ARSA was visualized by the conventional method. The new method exhibited 100% feasibility and was in complete agreement with the conventional method. Intra- and inter-observer agreement was excellent (κ = 1). The results of the study suggest that the “No ARSA” sign is an efficient and reliable screening tool for ARSA.

The so-called "bovine aortic arch": a possible biomarker for embolic strokes?

PURPOSE

To examine the prevalence of the so-called bovine aortic arch variation (common origin of the brachiocephalic trunk and the left common carotid artery) in embolic stroke patients, compared with a control group.

METHODS

Aortic arch branching patterns were retrospectively evaluated in 474 individuals with (n = 152) and without (n = 322) acute embolic stroke of the anterior circulation. Contrast-enhanced CT scans of the chest and neck (arterial contrast phase, 1-2-mm slice thickness) were used to evaluate aortic arch anatomy. The stroke cohort included 152 patients who were treated for embolic strokes of the anterior circulation between 2008 and 2018. A total of 322 randomly selected patients who had received thoracic CT angiographies within the same time frame were included as a control group.

RESULTS

With a prevalence of 25.7%, the bovine aortic arch variant was significantly more common among patients suffering from embolic strokes, compared with 17.1% of control patients (p = 0.039, OR = 1.67, 95%CI = 1.05-1.97). Stroke patients were more likely to show the bovine arch subtype B (left common carotid artery originating from the brachiocephalic trunk instead of the aortic arch) (10.5% vs. 5.0%, p = 0.039, OR = 2.25, 95%CI = 1.09-4.63), while subtype A (V-shaped common aortic origin of the brachiocephalic trunk and the left carotid) was similarly common in both groups. There was no significant difference regarding the frequency of other commonly observed variant branching patterns of the aortic arch.

CONCLUSION

The bovine aortic arch, particularly the bovine arch subtype B, was significantly more common among embolic stroke patients. This might be due to altered hemodynamic properties within the bovine arch.

Microarray analysis has no additional value in fetal aberrant right subclavian artery: description of 268 pregnancies and systematic literature review

OBJECTIVES

Fetal aberrant right subclavian artery (ARSA) is a relatively common sonographic finding. Several studies have reported a significant association between ARSA and Down syndrome, as well as 22q11.2 microdeletion. The objective of this study was to assess the risk of abnormal chromosomal microarray analysis (CMA) findings in a large cohort of pregnancies with fetal ARSA as an isolated, as well as a non-isolated, sonographic anomaly. A secondary objective was to review the literature, examining the frequency of chromosomal microarray aberrations in fetuses with isolated ARSA.

METHODS

Data from all pregnancies referred for invasive testing and CMA due to sonographic diagnosis of fetal ARSA, between 2013 and 2017, were obtained retrospectively from the computerized database of the Israeli Ministry of Health. The rate of clinically significant CMA findings in these fetuses was compared to that in a local control population of 2752 low-risk pregnancies with normal ultrasound and serum screening results. In addition, a literature search was conducted in PubMed, from inception to February 2018, of original studies in the English language describing the frequency and nature of microscopic and submicroscopic aberrations in fetuses with isolated ARSA.

RESULTS

Of 246 pregnancies with isolated ARSA that underwent CMA analysis, a clinically significant finding was detected in one (0.4%) pregnancy (trisomy 21). This rate did not differ significantly from that in the control population (P = 0.1574). Of 22 fetuses with non-isolated ARSA, one (4.5%) additional case of trisomy 21 was noted. The frequency of trisomy 21 in this cohort also did not differ from that in the control population (relative risk, 5.5 (95% CI, 0.8-37.6)). The literature search yielded 13 additional relevant papers, encompassing 333 cases of isolated ARSA. Of 579 cases overall (including those of the present study), 13 (2.2%) cases of trisomy 21 were detected, with no cases of 22q11.2 microdeletion.

CONCLUSION

While an association may exist between non-isolated ARSA and Down syndrome, isolated ARSA might better serve as a soft marker for Down syndrome, rather than a routine indication for invasive prenatal testing. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Axillary Lymph Node Metastasis in Gallbladder Carcinoma with Incidentally Detected Coexistence of Aberrant Right Subclavian Artery with Left-Sided Superior Vena Cava

The sequential development of port site recurrence, followed by recurrence in the axillary lymph node in gallbladder carcinoma is very infrequently reported in the literature. The representing 18F-fluorodeoxyglucose positron emission tomography-computed tomography image shows a metastatic right axillary lymph node in a case of gallbladder cancer developed following surgical removal of port site recurrence and six cycles of chemotherapy. The image also shows coexistence of two incidentally detected vascular anomalies, i.e., aberrant right subclavian artery and left-sided superior vena cava. Coexistence of both the vascular anomalies is rare among the general population and have their own clinical implications as described.

Incidence of an Aberrant Right Subclavian Artery on Second-Trimester Sonography in an Unselected Population

OBJECTIVES

The aim of this study was to assess the incidence of an aberrant right subclavian artery (ARSA) among an unselected population during second-trimester sonography and to review the importance of this conotruncal variant as a marker of Down syndrome.

METHODS

The presence or absence of an ARSA was assessed in an unselected population of 1913 second-trimester fetuses.

RESULTS

Among the 1913 patients, an ARSA was detected in 20 fetuses (1.04%), all with a normal karyotype. Thirteen of 20 fetuses had an isolated ARSA, and 7 of them were nonisolated. Associated abnormal sonographic findings were an intracardiac echogenic focus (n = 3), a choroid plexus cyst (n = 1), pyelectasis (n = 1) and tetralogy of Fallot (n = 2). One of the cases of tetralogy of Fallot was also associated with a persistent left superior vena cava, a persistent right umbilical vein, hydrocephalus, rhombencephalosynapsis, and unilateral renal agenesis. There were only 2 fetuses with Down syndrome in this group, and both of them had a normal origin of the right subclavian artery.

CONCLUSIONS

In an unselected population, an ARSA may be seen less frequently than in a high-risk population and may not be related to Down syndrome. An isolated ARSA is not a sufficient indication for karyotype analysis; it can be managed with noninvasive prenatal testing rather than invasive testing.

Aberrant Right Subclavian Artery: Correlation Between Fetal and Neonatal Abnormalities and Abnormal Genetic Screening or Testing

OBJECTIVES

To determine whether fetuses with an isolated aberrant course of the right subclavian artery (ARSA) have increased risk for chromosomal abnormalities, including trisomy 21 or 22q11 deletion.

METHODS

We performed a retrospective chart review of all fetuses with antenatally diagnosed ARSA. Data were collected from fetal anatomic surveys, fetal echocardiograms, noninvasive trisomy 21 screening programs, invasive genetic studies, and neonatal records.

RESULTS

Seventy-nine fetuses with ARSA were identified at 20.3 ± 3.8 weeks' gestation. Forty-eight fetuses underwent chromosomal evaluation. Of those, seven had trisomy 21. Four other fetuses had unusual karyotype abnormalities. All fetuses with genetic anomalies had additional aberrant ultrasound findings. There were three spontaneous fetal deaths (trisomy 21-2 and Wolf-Hirshhorn-1). Nine pregnancies were terminated because of abnormalities and one died as a result of hypoplastic left heart syndrome. No neonate was found or suspected to have 22q11.2 deletion. The ARSA was isolated in 43 fetuses; all had unremarkable neonatal outcomes, and none were readmitted within 6 months after discharge.

CONCLUSIONS

As an apparently isolated finding, ARSA is benign and not associated with trisomy 21 or 22q11.2 deletion. The finding of ARSA, however, warrants a detailed fetal ultrasound. All fetuses with ARSA and genetic anomalies had additional ultrasound findings.

First trimester ultrasound tests alone or in combination with first trimester serum tests for Down's syndrome screening

BACKGROUND

Down's syndrome occurs when a person has three, rather than two copies of chromosome 21; or the specific area of chromosome 21 implicated in causing Down's syndrome. It is the commonest congenital cause of mental disability and also leads to numerous metabolic and structural problems. It can be life-threatening, or lead to considerable ill health, although some individuals have only mild problems and can lead relatively normal lives. Having a baby with Down's syndrome is likely to have a significant impact on family life.Non-invasive screening based on biochemical analysis of maternal serum or urine, or fetal ultrasound measurements, allows estimates of the risk of a pregnancy being affected and provides information to guide decisions about definitive testing.Before agreeing to screening tests, parents need to be fully informed about the risks, benefits and possible consequences of such a test. This includes subsequent choices for further tests they may face, and the implications of both false positive and false negative screening tests (i.e. invasive diagnostic testing, and the possibility that a miscarried fetus may be chromosomally normal). The decisions that may be faced by expectant parents inevitably engender a high level of anxiety at all stages of the screening process, and the outcomes of screening can be associated with considerable physical and psychological morbidity. No screening test can predict the severity of problems a person with Down's syndrome will have.

OBJECTIVES

To estimate and compare the accuracy of first trimester ultrasound markers alone, and in combination with first trimester serum tests for the detection of Down's syndrome.

SEARCH METHODS

We carried out extensive literature searches including MEDLINE (1980 to 25 August 2011), Embase (1980 to 25 August 2011), BIOSIS via EDINA (1985 to 25 August 2011), CINAHL via OVID (1982 to 25 August 2011), and The Database of Abstracts of Reviews of Effects (the Cochrane Library 2011, Issue 7). We checked reference lists and published review articles for additional potentially relevant studies.

SELECTION CRITERIA

Studies evaluating tests of first trimester ultrasound screening, alone or in combination with first trimester serum tests (up to 14 weeks' gestation) for Down's syndrome, compared with a reference standard, either chromosomal verification or macroscopic postnatal inspection.

DATA COLLECTION AND ANALYSIS

Data were extracted as test positive/test negative results for Down's and non-Down's pregnancies allowing estimation of detection rates (sensitivity) and false positive rates (1-specificity). We performed quality assessment according to QUADAS criteria. We used hierarchical summary ROC meta-analytical methods to analyse test performance and compare test accuracy. Analysis of studies allowing direct comparison between tests was undertaken. We investigated the impact of maternal age on test performance in subgroup analyses.

MAIN RESULTS

We included 126 studies (152 publications) involving 1,604,040 fetuses (including 8454 Down's syndrome cases). Studies were generally good quality, although differential verification was common with invasive testing of only high-risk pregnancies. Sixty test combinations were evaluated formed from combinations of 11 different ultrasound markers (nuchal translucency (NT), nasal bone, ductus venosus Doppler, maxillary bone length, fetal heart rate, aberrant right subclavian artery, frontomaxillary facial angle, presence of mitral gap, tricuspid regurgitation, tricuspid blood flow and iliac angle 90 degrees); 12 serum tests (inhibin A, alpha-fetoprotein (AFP), free beta human chorionic gonadotrophin (ßhCG), total hCG, pregnancy-associated plasma protein A (PAPP-A), unconjugated oestriol (uE3), disintegrin and metalloprotease 12 (ADAM 12), placental growth factor (PlGF), placental growth hormone (PGH), invasive trophoblast antigen (ITA) (synonymous with hyperglycosylated hCG), growth hormone binding protein (GHBP) and placental protein 13 (PP13)); and maternal age. The most frequently evaluated serum markers in combination with ultrasound markers were PAPP-A and free ßhCG.Comparisons of the 10 most frequently evaluated test strategies showed that a combined NT, PAPP-A, free ßhCG and maternal age test strategy significantly outperformed ultrasound markers alone (with or without maternal age) except nasal bone, detecting about nine out of every 10 Down's syndrome pregnancies at a 5% false positive rate (FPR). In both direct and indirect comparisons, the combined NT, PAPP-A, free ßhCG and maternal age test strategy showed superior diagnostic accuracy to an NT and maternal age test strategy (P < 0.0001). Based on the indirect comparison of all available studies for the two tests, the sensitivity (95% confidence interval) estimated at a 5% FPR for the combined NT, PAPP-A, free ßhCG and maternal age test strategy (69 studies; 1,173,853 fetuses including 6010 with Down's syndrome) was 87% (86 to 89) and for the NT and maternal age test strategy (50 studies; 530,874 fetuses including 2701 Down's syndrome pregnancies) was 71% (66 to 75). Combinations of NT with other ultrasound markers, PAPP-A and free ßhCG were evaluated in one or two studies and showed sensitivities of more than 90% and specificities of more than 95%.High-risk populations (defined before screening was done, mainly due to advanced maternal age of 35 years or more, or previous pregnancies affected with Down's syndrome) showed lower detection rates compared to routine screening populations at a 5% FPR. Women who miscarried in the over 35 group were more likely to have been offered an invasive test to verify a negative screening results, whereas those under 35 were usually not offered invasive testing for a negative screening result. Pregnancy loss in women under 35 therefore leads to under-ascertainment of screening results, potentially missing a proportion of affected pregnancies and affecting test sensitivity. Conversely, for the NT, PAPP-A, free ßhCG and maternal age test strategy, detection rates and false positive rates increased with maternal age in the five studies that provided data separately for the subset of women aged 35 years or more.

AUTHORS' CONCLUSIONS

Test strategies that combine ultrasound markers with serum markers, especially PAPP-A and free ßhCG, and maternal age were significantly better than those involving only ultrasound markers (with or without maternal age) except nasal bone. They detect about nine out of 10 Down's affected pregnancies for a fixed 5% FPR. Although the absence of nasal bone appeared to have a high diagnostic accuracy, only five out of 10 affected Down's pregnancies were detected at a 1% FPR.

Chromosomal microarray analysis in fetuses with aberrant right subclavian artery

OBJECTIVE

To evaluate the association between aberrant right subclavian artery (ARSA), with or without additional risk factors for aneuploidy or ultrasound abnormality, and results of chromosomal microarray analysis (CMA).

METHODS

This was a multicenter study of fetuses diagnosed with ARSA that underwent genetic analysis by CMA, all samples being analyzed in the same laboratory. Clinical investigation included nuchal translucency measurement, first- and second-trimester maternal serum screening, early and late second-trimester fetal anatomy scans and fetal echocardiography. Comparative genomic hybridization microarray analysis or single-nucleotide polymorphism array technology was used for CMA of DNA samples obtained from amniotic fluid.

RESULTS

CMA results were available for 63 fetuses with ARSA. In 36 fetuses, ARSA was an isolated finding, and no pathogenic variant was found. Additional ultrasound findings and/or risk factors for aneuploidy were present in 27 fetuses, five of which had pathogenic CMA results. Of these five, trisomy 21 was detected in a fetus with echogenic intracardiac focus (EIF), 22q11 deletion was detected in a fetus with EIF and an increased risk of trisomy 21 of 1:230 from maternal serum screening, 22q11 duplication was detected in a fetus with hypoplastic right kidney and choroid plexus cyst and 22q11 deletion was detected in a fetus with right aortic arch and clubfoot. The fifth fetus had increased nuchal translucency thickness (4 mm) and a ventricular septal defect, and CMA identified both 22q11 deletion and 1q21 duplication.

CONCLUSIONS

In fetuses with isolated ARSA, an invasive procedure for CMA is not indicated. However, CMA is recommended when additional ultrasound abnormalities or risk factors for aneuploidy are observed. The chromosomal findings in four of the five cases with an abnormal CMA result in our study would not have been detected by standard fetal chromosomal testing. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.

Fetal Aortic Arch Anomalies: Key Sonographic Views for Their Differential Diagnosis and Clinical Implications Using the Cardiovascular System Sonographic Evaluation Protocol

Aortic arch anomalies are present in 1% to 2% of the general population and are commonly associated with congenital heart disease, chromosomal defects, and tracheaesophageal compression in postnatal life. The sonographically based detection of aortic arch anomalies lies in the 3-vessel and trachea view. Although highly sensitive, this view alone does not allow identification of the aortic arch branching pattern, which prevents an accurate diagnosis. The systematic addition of a subclavian artery view as part of a standardized procedure may be useful in the differential diagnosis of these conditions. We describe the sonographic assessment of fetal aortic arch anomalies by combining 2 fetal transverse views: the 3-vessel and trachea view and the subclavian artery view, which are included in the cardiovascular system sonographic evaluation protocol. We also review the sonographic findings and the clinical implications of fetal aortic arch anomalies.

Prenatal Associated Features in Fetuses Diagnosed with an Aberrant Right Subclavian Artery

Objective: The objective of this study was to determine the frequency and the nature of associated anomalies, especially malformations and chromosome abnormalities, in a population of fetuses with an aberrant right subclavian artery (ARSA). Materials and Methods: This is a 7-year descriptive study. All patients whose fetus had an ARSA diagnosed by ultrasound performed during the 1st, 2nd, or 3rd trimester of pregnancy were included, regardless of their risk of chromosomal abnormalities. Results: Between May 2007 and April 2014, an ARSA was diagnosed in 120 fetuses. The outcome was found in 108 cases (90%). ARSA was an isolated finding in 54/108 cases (50%). In 20% (22/108) of the fetuses, chromosomal abnormalities were detected. No chromosomal abnormalities were found in fetuses with an isolated ARSA. 82% (18/22) of chromosomal abnormalities were usual, such as trisomies 21 and 18, monosomy X, and 22q11.2 deletion. 21% (23/108) of the fetuses presenting an ARSA were associated with having a congenital heart disease. Conclusion: The presence of an isolated ARSA is a condition rarely associated with a chromosomal abnormality. The decision to perform an invasive karyotyping procedure under such circumstances or not may be made according to the principle of parental autonomy after extensive counselling and mostly a thorough assessment of the fetus.

Aberrant right subclavian artery in fetuses with Down syndrome: a systematic review and meta-analysis

OBJECTIVES

The primary objective was to estimate the prevalence of aberrant right subclavian artery (ARSA) in fetuses with Down syndrome. Secondary objectives were to assess the prevalence of ARSA in euploid fetuses, the feasibility of ultrasound evaluation of the right subclavian artery (RSA) in the first and second trimesters of pregnancy, the performance of ARSA in screening for trisomy 21 and its association with other abnormalities.

METHODS

Web-based databases (PubMed, EMBASE and MEDLINE) were searched up to July 2014. The STROBE, PRISMA and QUIPS instruments were used to assess all included studies and for reporting of methodology, results and conclusions. Original studies that reported prenatal ultrasound evaluation of ARSA, assessment of its prevalence in Down-syndrome and euploid fetuses, feasibility of ultrasound evaluation of the RSA in the first and second trimesters of pregnancy and correlation of ARSA with other abnormalities were included, excluding duplications and case reports. Collected data were summarized to estimate prevalence and feasibility. A meta-analysis was performed pooling the study-specific positive and negative likelihood ratios (LR+ and LR-), detection rates and false-positive rates for trisomy 21.

RESULTS

Prevalence of ARSA in Down-syndrome fetuses was 23.6% (95% CI, 19.4-27.9%), whereas in euploid fetuses it was 1.02% (95% CI, 0.86-1.10%). Ultrasound evaluation of the RSA course and origin in the first and second trimesters of pregnancy was feasible in 85% and 98% of cases (first and second trimester, respectively) and it was directly related to sonographic experience and fetal crown-rump length and inversely related to maternal body mass index. In more than 20% of fetuses with ARSA there was an association with other abnormalities but ARSA seemed to be an independent marker of trisomy 21. The meta-analysis showed that ARSA is a significant risk factor for Down syndrome (pooled LR+ = 26.93, 95% CI, 19.36-37.47, P for effect < 0.001, P for Q = 0.3, I(2) = 17.3%), whereas normal RSA is a significant protective marker (pooled LR- = 0.71, 95% CI, 0.51-0.99, P for effect = 0.043, P for Q = 0.9, I(2) = 0%).

CONCLUSIONS

ARSA appears to be a clinically useful prenatal ultrasound marker of Down syndrome. Additional testing when ARSA is diagnosed should involve evaluation of all risk factors by applying a mathematical model. There is insufficient evidence to recommend fetal karyotyping in cases with isolated ARSA. If the background risk is higher or additional markers are present, full fetal karyotyping is advisable, including analysis for 22q11 microdeletion.

Cardiovascular System Sonographic Evaluation Algorithm: A New Sonographic Algorithm for Evaluation of the Fetal Cardiovascular System in the Second Trimester

OBJECTIVES

To evaluate the reproducibility and feasibility of the new cardiovascular system sonographic evaluation algorithm for studying the extended fetal cardiovascular system, including the portal, thymic, and supra-aortic areas, in the second trimester of pregnancy (19-22 weeks).

METHODS

We performed a cross-sectional study of pregnant women with healthy fetuses (singleton and twin pregnancies) attending our center from March to August 2011. The extended fetal cardiovascular system was evaluated by following the new algorithm, a sequential acquisition of axial views comprising the following (caudal to cranial): I, portal sinus; II, ductus venosus; III, hepatic veins; IV, 4-chamber view; V, left ventricular outflow tract; VI, right ventricular outflow tract; VII, 3-vessel and trachea view; VIII, thy-box; and IX, subclavian arteries. Interobserver agreement on the feasibility and exploration time was estimated in a subgroup of patients. The feasibility and exploration time were determined for the main cohort. Maternal, fetal, and sonographic factors affecting both features were evaluated.

RESULTS

Interobserver agreement was excellent for all views except view VIII; the difference in the mean exploration time between observers was 1.5 minutes (95% confidence interval, 0.7-2.1 minutes; P < .05). In 184 fetuses (mean gestational age ± SD, 20 ± 0.6 weeks), the feasibility of all views was close to 99% except view VIII (88.7%). The complete feasibility of the algorithm was 81.5%. The mean exploration time was 5.6 ± 4.2 minutes. Only the occiput anterior fetal position was associated with a lower frequency of visualization and a longer exploration time (P < .05).

CONCLUSIONS

The cardiovascular system sonographic evaluation algorithm is a reproducible and feasible approach for exploration of the extended fetal cardiovascular system in a second-trimester scan. It can be used to explore these areas in normal and abnormal conditions and provides an integrated image of extended fetal cardiovascular anatomy.

Second-trimester fetal aberrant right subclavian artery: original study, systematic review and meta-analysis of performance in detection of Down syndrome

OBJECTIVES

First, to estimate the prevalence of fetal aberrant right subclavian artery (ARSA) in our population and its association with Down syndrome. Second, to determine the feasibility of ultrasound to visualize ARSA in the three planes. Finally, to carry out a systematic review of the literature on the performance of second-trimester ARSA to identify fetuses with Down syndrome.

METHODS

ARSA was assessed by ultrasound in the axial plane and confirmed in the longitudinal and coronal planes during the second half of pregnancy in women attending our unit (from February 2011 to December 2012). A search of diagnostic tests for the assessment of ARSA was carried out in international databases. Relevant studies were subjected to a critical reading, and meta-analysis was performed with Meta-DiSc.

RESULTS

Of the 8781 fetuses in our population (mean gestational age: 24 ± 5.4 weeks), 22 had Down syndrome. ARSA was detected in the axial view in 60 cases (0.7%) and confirmed in the coronal view in 96.7% and in the longitudinal view in 6.7% (P < 0.001). Seven cases with ARSA had Down syndrome and all were in the non-isolated-ARSA group. The estimates of positive likelihood ratio (LR) were 0 for isolated ARSA and 199 (95% CI, 88.9-445.2) for non-isolated ARSA. In the systematic review, six studies were selected for quantitative synthesis. The pooled estimates of positive and negative LRs for global ARSA were, respectively, 35.3 (95% CI, 24.4-51.1) and 0.75 (95% CI, 0.64-0.87). For isolated ARSA, the positive and negative LRs were 0 (95% CI, 0.0-14.7) and 0.98 (95% CI, 0.94-1.02), respectively.

CONCLUSIONS

The prevalence of ARSA seems close to 1%. The coronal plane is the most suitable for its confirmation after detection in the axial plane. Detection of isolated or non-isolated ARSA should guide decisions about karyotyping given that isolated ARSA shows a weak association with Down syndrome.

Aberrant subclavian artery origin in tetralogy of Fallot with pulmonary stenosis is associated with chromosomal or genetic abnormality

We determined the relationship between aortic arch anatomy in tetralogy of Fallot with pulmonary stenosis and chromosomal or genetic abnormality, by performing analysis of 257 consecutive patients undergoing surgical repair from January, 2003 to March, 2011. Chromosomal or genetic abnormality was identified in 49 of the 257 (19%) patients. These included trisomy 21 (n = 14); chromosome 22q11.2 deletion (n = 16); other chromosomal abnormalities (n = 9); CHARGE (n = 2); Pierre Robin (n = 2); and Kabuki, Alagille, Holt-Oram, Kaufman McKusick, Goldenhar, and PHACE (n = 1 each). Aortic anatomy was classified as left arch with normal branching, right arch with mirror image branching, left arch with aberrant right subclavian artery, or right arch with aberrant left subclavian artery. Associated syndromes occurred in 33 of 203 (16%) patients with left arch and normal branching (odds ratio 1); three of 36 (8%) patients with right arch and mirror image branching (odds ratio 0.4, 95% confidence interval 0.1-1.6); seven of eight (88%) patients with left arch and aberrant right subclavian artery (odds ratio 36, 95% confidence interval 4-302); and six of 10 (60%) patients with right arch and aberrant left subclavian artery (odds ratio 8, 95% confidence interval 2-26). Syndromes were present in 13 of 18 (72%) patients with either right or left aberrant subclavian artery (odds ratio 15, 95% confidence interval 4-45). Syndromes in patients with an aberrant subclavian artery included trisomy 21 (n = 4); chromosome 22q11.2 deletion (n = 5); and Holt-Oram, PHACE, CHARGE, and chromosome 18p deletion (n = 1 each). Aberrant right or left subclavian artery in tetralogy of Fallot with pulmonary stenosis is associated with an increased incidence of chromosomal or genetic abnormality, whereas right aortic arch with mirror image branching is not. The assessment of aortic arch anatomy at prenatal diagnosis can assist counselling.

Use of a high-frequency linear transducer and MTI filtered color flow mapping in the assessment of fetal heart anatomy at the routine 11 to 13 + 6-week scan: a randomized trial

OBJECTIVE

To prospectively assess the contribution of a high-frequency linear transducer and of moving target indicator (MTI) filtered color flow mapping in the visualization of cardiac fetal anatomy at the routine 11 to 13 + 6-week scan.

METHODS

This was a cross-sectional prospective study, including 300 singleton fetuses at 11 to 13 + 6 weeks' gestation. Patients were randomized into four groups and a detailed fetal cardiac examination was conducted transabdominally using either a conventional curvilinear transducer, a conventional curvilinear transducer and MTI filtered color flow mapping, a high-frequency linear transducer or a high-frequency linear transducer and MTI filtered color flow mapping. Regression analysis was used to investigate the effect on the ability to visualize different cardiac structures of the following parameters: gestational age at ultrasound examination; fetal crown-rump length (CRL); maternal body mass index (BMI); transducer-heart distance; the technique used at ultrasound; and the position of the placenta.

RESULTS

The four-chamber view was visualized in 89.0% of fetuses and regression analysis showed this rate was correlated with CRL and the use of MTI filtered color flow mapping during ultrasonography, and inversely correlated with BMI and transducer-heart distance. Use of a conventional curvilinear transducer and MTI filtered color flow mapping allowed visualization of the four-chamber view in 97.3% of fetuses, while this was only possible in 84.0% of fetuses using a high-frequency linear transducer. The left and right outflow tracts were visualized in 62.3 and 57.7% of fetuses, respectively. Regression analysis showed that the ability to visualize the left or the right outflow tract was correlated with the use of MTI filtered color flow mapping during scanning and was inversely correlated with transducer-heart distance. The use of a conventional curvilinear transducer and MTI filtered color flow mapping allowed visualization of the left and right outflow tracts in 96.0 and 97.3% of fetuses, respectively, while this was only possible in 37.3 and 26.7% of fetuses using a high-frequency linear transducer.

CONCLUSIONS

During the routine 11 to 13 + 6-week scan, the use of MTI filtered color flow mapping but not of a high-frequency linear transducer, improves visualization of cardiac anatomy.

Aberrant right subclavian artery: incidence and correlation with other markers of Down syndrome in second-trimester fetuses

OBJECTIVE

To assess the incidence of aberrant right subclavian artery (ARSA) and other strong markers of Down syndrome and their correlation in a large population of second-trimester Down syndrome fetuses assessed in a tertiary referral center.

METHODS

Presence or absence of ARSA and other major ultrasound markers of Down syndrome was assessed in a population of 106 second-trimester Down syndrome fetuses referred to our unit for expert assessment and/or termination of pregnancy after karyotyping performed for positive first- or second-trimester screening or advanced maternal age or on maternal request. All cases in which the diagnosis of Down syndrome followed the ultrasound detection of major anomalies or soft markers were excluded from the study, as were all cases with a gestational age less than 14 + 0 weeks. We searched for the ARSA on the three vessels and trachea view using color or power Doppler. All fetuses underwent a thorough anatomic assessment and fetal echocardiography. The other Down syndrome markers assessed were: absent or hypoplastic nasal bone (NB-), defined as length < 5(th) centile; nuchal fold ≥ 5 mm; and mild pyelectasis (> 5 mm). In addition, the presence of major cardiac and extracardiac defects was recorded. A correlation analysis was then performed in order to investigate possible associations between markers and/or major anomalies. Postmortem or postnatal diagnostic confirmation was available in all cases.

RESULTS

The mean (SD) gestational age at ultrasound assessment was 20.4 (4.1) weeks. The incidence of the various variables in the population of Down syndrome fetuses was: ARSA, 25%; NB-, 43%; nuchal fold ≥ 5 mm, 16%; pyelectasis, 17%; major heart defects, 41%; atrioventricular septal defect, 25%; and extracardiac anomaly, 24%. The presence of ARSA did not correlate with any of the other variables. The only positive correlations (P < 0.05) were between NB- and pyelectasis, and between cardiac and extracardiac defects.

CONCLUSIONS

This represents the largest Down syndrome population assessed for ARSA. In this series, the incidence of ARSA was 25%, lower than previously reported in much smaller series. Its presence did not correlate with the presence of any other marker or major anomaly, including heart defects.

Prenatally detectable congenital heart defects in fetuses with Down syndrome

OBJECTIVE

To document the incidence of congenital heart defects (CHD) that are detectable echocardiographically in the fetus with trisomy 21 and the relationship with nuchal translucency, fetal sex and ethnicity.

METHODS

Data on fetuses with a karyotypic diagnosis of trisomy 21 were collected between January 2002 and March 2010. The data were analyzed for the gestational age at examination, maternal age, reason for referral for fetal echocardiography, cardiac diagnosis, fetal sex, ethnicity and outcome.

RESULTS

Of 917 fetuses with trisomy 21, 487 had a diagnostic echocardiogram. Cardiac examination was performed before 14 weeks' gestation in 75% of cases. The main reasons for referral were increased nuchal translucency (NT) in 76% of cases, suspected cardiac abnormality in 15% and an extracardiac anomaly in 6%. Structural CHD was found in 164/487 (34%), or 98/412 (24%) if those referred for suspected CHD are removed from the analysis. The most common diagnosis was atrioventricular septal defect (AVSD) (115/487, 24%). The ratio of female to male fetuses with AVSD was 29%:18% (P = 0.003). There was no difference in the incidence of AVSD with ethnicity. The pregnancy continued in 36 cases, but three were lost to follow-up; of the known outcomes there were 10 intrauterine deaths, six of which had structural heart disease, and 23 live births, 15 of which had CHD.

CONCLUSION

Most fetuses (66-76%) with trisomy 21 have a structurally normal heart on echocardiography. The presence of structural CHD was not associated with increased NT. The increased incidence of AVSD in females was confirmed in our study, although an ethnic difference could not be confirmed. CHD does not appear to increase the chance of spontaneous intrauterine loss in ongoing pregnancies.

Aberrant right subclavian artery at 16 to 23 + 6 weeks of gestation: a marker for chromosomal abnormality

OBJECTIVES

This study was carried out to determine the feasibility of defining the position of the right subclavian artery (RSA) by fetal echocardiography between 16 and 23 weeks of gestation, and the association between an aberrant right subclavian artery (ARSA) and chromosomal and cardiac defects.

METHODS

We examined the position of the RSA in all patients who attended our unit for a fetal cardiac scan. The assessment was carried out using a transverse view of the fetal chest sweeping up from the level of the aortic arch, using color flow mapping. An ARSA was diagnosed when this vessel was not seen in the normal position and an arterial vessel was seen crossing behind the trachea towards the right arm, arising as a fourth branch of the aortic arch, at a lower level than normal.

RESULTS

The course of the RSA could be identified in more than 95% of the 2799 fetuses examined between 16 and 23 + 6 weeks of gestation. An ARSA was found in 43 fetuses. The incidence was 1.5% in normal fetuses, 28.6% in fetuses with trisomy 21, 18.2% in fetuses with trisomy 18 and 8% in fetuses with other chromosomal defects. There was an association between an ARSA and cardiac defects in seven of the 43 fetuses (16%), and three of these seven fetuses had a normal karyotype.

CONCLUSIONS

Assessment of the RSA by a fetal cardiologist is possible in almost all cases. The finding of an ARSA is much more common in fetuses with chromosomal defects, in particular trisomy 21 (where the prevalence of an ARSA was 29%), compared with euploid fetuses. Moreover, the presence of an ARSA may be associated with an increased incidence of intracardiac malformations. Examination of the position of the RSA is likely to become a routine ultrasound marker for chromosomal abnormalities in the second trimester of pregnancy.