Prenatal diagnosis of an aberrant right subclavian artery: four vessels arising from the aortic arch?

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.

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.

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.

Prenatal diagnosis of aberrant right subclavian artery in an unselected population

Purpose

The purpose of this study was to determine the frequency of aberrant right subclavian artery (ARSA) among unselected fetuses and to evaluate its association with chromosomal abnormalities and other congenital anomalies.

Methods

In all, 7,547 fetuses (gestational age, 20 to 34 weeks) were examined using routine antenatal sonography at our institution between April 2014 and September 2015. The right subclavian artery was assessed using grayscale and color Doppler ultrasonography in the transverse 3-vessel and tracheal view, and confirmed in the coronal plane.

Results

ARSA was found in 28 fetuses (0.4%). Further, 27 of these 28 fetuses were euploid (96.4%). Trisomy 18 was the only chromosomal anomaly (3.6%) found in the study sample. ARSA was an isolated finding in 23 of the 28 cases (82.1%). In the remaining three cases (10.7%), ARSA was accompanied with extracardiac anomalies. Other cardiac defects were present in three cases (10.7%).

Conclusion

Isolated ARSA does not seem to be associated with a significantly increased risk of aneuploidy. However, the possibility of fetal karyotyping, which is a more invasive procedure, should be discussed in the light of the overall risk of the fetus.

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.

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.