[Left aortic arch--right descending aorta--right ductus arteriosus (encircling aortic arch). A rare malformation of the aortic arches]

Prenatal diagnosis and postnatal outcome of persistent right ductus arteriosus: a report of three cases

The ductus arteriosus is a fetal vascular connection between the main pulmonary artery and aorta that diverts blood away from the pulmonary bed. Left and right ductus arteriosi emerge from embryological aortic arches. In normal embryologic cardiac development, both right aortic and ductal arches regress and the left ones persist. Persistent right ductus arteriosus (rDA) is one of the congenital anomalies of the ductal arch. In this paper, we report three cases of persistent right ductus arteriosus with right aortic arch.

Right ductus arteriosus: facts and theory

OBJECTIVE

To report fetal right-sided persistent ductus arteriosus (RPDA) in association with right aortic arch (RAA).

STUDY DESIGN

Extensive sonographic fetal anatomical scans were consecutively performed on 19,874 private, self-referred pregnant women who wanted early sonographic detection of fetal anomalies.

RESULTS

Of 19,874 transvaginal (TVS) sonographic examinations 40 fetuses had right aortic arch (RAA) and four of them (10%) had RPDA. We also diagnosed seven cases of RPDA with involvement of the left aortic arch where a right-curving pattern ("L" shape) parallel to the right pulmonary artery was suggestive of Rt. DA with left aortic arch. Only one (9%) of the RPDA cases was associated with a cardiac anomaly (double outlet right ventricle). None of the other eight RPDA cases had any discernible anomalies, and all of the fetuses with RPDA had normal karyotypes.

CONCLUSIONS

In 10% of the fetuses with right aortic arch the ductal arch was also on the right side. An unusual-looking DA may be a RPDA associated with the left aortic arch. In most cases, the RPDA is a normal variant not associated with other anomalies.