Associated anomalies and outcome of fetal aberrant right subclavian artery

Purpose To determine the frequency of aberrant right subclavian artery among the low-risk fetuses and to evaluate its association with chromosomal abnormalities and the other congenital heart diseases. Methods A total of 4,125 consecutive fetuses were examined for the presence of aberrant right subclavian artery that arises from the descending aorta distal to the left subclavian artery. Results Aberrant right subclavian artery was detected in 17 cases (0.4%). In nine cases it was an isolated finding. In four cases (23.5%) it was accompanied by another cardiac defect. Extracardiac malformations were present in three fetuses (17.6%). Among the 13 cases of aberrant right subclavian artery in which the karyotypes were known, one case presented with Down syndrome (7.6%). In this fetus, aberrant right subclavian artery was the only finding. Conclusion These findings suggest that aberrant right subclavian may be an isolated finding in trisomy 21. The visualization of subclavian artery should be a part of fetal echocardiographic examination as it may be a valuable marker for Down syndrome.