OC176: The aberrant right subclavian artery is a common aortic arch abnormality in fetuses with Down's syndrome

Abstract

Objective: Conversely to the normal right subclavian artery arising from the brachiocephalic artery, an aberrant right subclavian artery (ARSA) arises as a separate vessel from the aortic isthmus and crosses to the right, behind the trachea. This variant is present in less than 1% of the normal population but pediatric cardiology observations report on a frequent occurrence in subjects with Down’s syndrome (DS). The purpose of this study was to assess the possibility of detecting an ARSA in fetuses with DS. Patients and Methods: 14 fetuses with prenatally detected DS were examined between 18 and 33 weeks of gestation. The right subclavian artery was visualized in the transverse three-vesseltrachea view of the upper thorax using color Doppler to detect a normal arising vessel or an ARSA. Results: An ARSA was identified in 35.7% (5/14) of trisomy 21 fetuses. In only one fetus it was associated with a cardiac defect (AVSD) and the four others it was either isolated (n = 1) or associated with an intracardiac echogenic focus. Conclusions: This preliminary study suggests that the in utero identification of an ARSA may be a new ultrasound marker found in fetuses with Down’s syndrome.