Isolated aberrant right subclavian artery: should invasive intervention be recommended in the era of noninvasive prenatal tests?

Objective: An aberrant right subclavian artery (ARSA) is an aor-tic arch anomaly isolated or associated with other ultrasound markers and/or congenital anomalies. This study aimed to eval-uate the necessity of invasive prenatal tests (PIT) in cases with isolated ARSA (iARSA) in prenatal sonography.Materials and Methods: The presence of ARSA was evaluated retrospectively in 7690 fetuses who underwent a second -trimes-ter ultrasonography evaluation between March 2015 and Feb-ruary 2021. PIT was recommended for patients with non-iARSA. cfDNA test (including 22q11.2 microdeletion/duplication syn-drome (MMS) or PIT was suggested for patients with iARSA.Results: The mean week of gestation was 20.26 +/- 3.93 in 95 fetus-es diagnosed with ARSA. Of the fetuses, fourty-two (44%) had iARSA, and 53 (56%) had additional findings. No chromosomal abnormality was found in any of the isolated cases. Trisomy 21 in 14, Trisomy 18 in one, 47,XX,+i(9)(p10) in one of 53 were found in non-isolated cases. Additional abnormalities and/or soft ul-trasound markers were accompanied in all fetuses with chromo-somal abnormalities. Conclusion: When iARSA is detected in prenatal ultrasonogra-phy, cfDNA testing may be sufficient, including 22q11.2 MMS. However, PIT should be recommended in the presence of structural abnormalities, soft ultrasound markers, or increased risk in the antenatal screening test.