Aberrant right subclavian artery in the absence of other prenatal ultrasound findings: Should we still be concerned?

ABSTRACT

OBJECTIVE: To analyze the value of prenatal diagnostic genetic testing in cases with isolated aberrant right subclavian artery (ARSA). METHODS: This is a retrospective cohort study, conducted between January 2015-January 2022 in a fetal medicine center. Women who had an ultrasound scan and diagnosed with fetal ARSA were included. Ultrasonographic characteristics, genetic, obstetric, and neonatal outcomes were collected and analyzed. RESULTS: A total of 240 fetuses with ARSA were identified and included to the analysis. Eighty-two of the group had isolated ARSA (34.2%, 82/240), 57 had additional soft markers (23.8%, 57/240) and 101 had additional major ultrasonographic abnormalities (42.1%, 101/240). Genetic results were available in 196 cases (81.7%, 196/240). Seventy-four of isolated ARSA cases underwent genetic testing (90.2%, 74/82). A chromosomal abnormality was present in 60 cases; 54 (22.5%, 54/240) aneuploidies and 6 (2.5%, 6/240) copy number variants. Five (6.1%) of the isolated ARSA cases had chromosomal abnormalities. All of these five cases had prenatal genetic testing due to high-risk aneuploidy screening fetuses who had ARSA with at least one additional anomaly had the highest chromosomal abnormality rate (38.6%, 39/101). Seventy-seven of isolated ARSA cases were liveborn (93.9%, 77/82). CONCLUSION: Our results supports the evidence from the literature that isolated ARSA confers a very low-risk for aneuploidy, if the aneuploidy screening tests are low-risk. Also, chromosomal microarray analysis did not yield any extra information in isolated ARSA.