Rare vascular ring of right aortic arch and aberrant left subclavian artery in association with bilateral ductus arteriosus

Vascular rings are congenital aortic arch anomalies that compress the trachea and esophagus, causing symptoms related to these two structures. One of the common types of vascular ring is formed by a right aortic arch, aberrant left subclavian artery and left-sided ductus arteriosus1. Bilateral ductus arteriosus is uncommon and can also result in a vascular ring2; it has been reported previously in association with right aortic arch and aberrant left subclavian artery3–5. We describe a rare vascular ring composed of a right aortic arch, aberrant left subclavian artery and bilateral ductus arteriosus. A 27-year-old woman was referred to our institution at 25 weeks of gestation for fetal echocardiography because of a suspected vascular ring. Two-dimensional color Doppler imaging revealed a right aortic arch, aberrant left subclavian artery and bilateral ductus arteriosus, resulting in two vascular rings, one being small and O-shaped and the other being U-shaped (Figure 1). Four-dimensional (4D) color Doppler with spatiotemporal image correlation (STIC) HD-flow mode (Voluson E10; GE Healthcare, Zipf, Austria) clearly showed the spatial relationships of these vessels and the trachea (Figure 1). No extracardiac or other cardiac anomalies were found. Fetal karyotyping and chromosomal microarray analysis (Affymetrix 750K; Thermo Fisher Scientific, Santa Clara, CA, USA) were normal. A female neonate was delivered vaginally at 40 + 5 weeks of gestation with a birth weight of 3280 g. Computed tomography (CT) was performed 3 days postpartum, which confirmed the formation of a complete vascular ring by the right aortic arch, aberrant left subclavian artery and bilateral ductus arteriosus. A slight indentation on the left side of the trachea was noted, which was produced by the left posterior ductus arteriosus (Figure 2). During the 2-month follow-up period, the left and right ductus arteriosus were observed to close spontaneously at 5 and 42 days after delivery, respectively. The patient had remained asymptomatic at the time of writing. Prenatal detection of a vascular ring by fetal echocardiography in this case had the following clinical implications: first, fetal karyotype analysis and genetic testing were recommended4; second, close monitoring of the patency of bilateral ductus arteriosus after birth was indicated as a precautionary measure against excessive pulmonary blood flow. The O-shaped complete ring appears to be anatomically 'tighter' than the U-shaped ring formed by a right aortic arch, aberrant left subclavian artery and left-sided ductus arteriosus. Surgical release of the vascular ring is likely required. Thus, further CT imaging and long-term follow-up are warranted. In conclusion, we present a case of a rare vascular ring formed by a right aortic arch and aberrant left subclavian artery in association with bilateral ductus arteriosus. Prenatal diagnosis is important to facilitate early clinical and imaging evaluation. Fetal echocardiography with application of 4D color Doppler with STIC HD-flow mode facilitates demonstration of the spatial relationships of the aortic arch branches and trachea. CT imaging after birth provides accurate anatomical information regarding the severity of the narrowing of the ring as well as the tracheoesophageal compression. This work was funded by the National Key Research and Development Program (2016YFC1000500).