Fetal aberrant right subclavian artery (ARSA) - a potential new soft marker in the genetic scan?

PURPOSE

The aim of this study was to evaluate the prevalence of an aberrant right subclavian artery (ARSA) in a mixed-risk population in the second trimester and to assess its potential as a new soft marker in the genetic scan.

MATERIALS AND METHODS

Fetal echocardiography was performed prospectively in 1337 fetuses at 16 - 28 weeks of gestation during a 12-month period at two referral centers for prenatal diagnosis. The presence of ARSA was verified by visualization of the transverse 3-vessel trachea view with color Doppler sonography.

RESULTS

The total rate of fetuses with an ARSA was 1.05 % (14 / 1337). The spectrum of associated findings in affected fetuses included: one trisomy 21, one unbalanced inversion of chromosome 9, one triploidy and two non-chromosomally related structural defects. Nine fetuses had no anomalies. The calculated odds ratio for the presence of an ARSA in the case of Down syndrome compared with healthy fetuses was 12.6 (95 % CI, 1.93 - 86.10).

CONCLUSION

The presence of an ARSA is more common in fetuses with trisomy 21 and other chromosomal defects than in healthy fetuses. Although it can be considered as a weak marker, the second trimester diagnosis of an ARSA should prompt a detailed search for additional "soft markers" and structural defects.