Ultrasound Images of a 22 Week Fetal Heart Showing Rare Concurrence of Aberrant Right Subclavian Artery and Persistent Left Superior Vena Cava

Abstract

An aberrant right subclavian artery (ARSA) and persistent left superior vena cava (PLSVC) are rare congenital anomalies of the cardiovascular system. This case presents the rare copresence of an ARSA and PLSVC, identified in a 22 week old fetus. The ARSA, an atypical anatomical variant where the right subclavian artery arises abnormally from the aortic arch, was observed along with the PLSVC, also an anatomical variation where the left superior vena cava persists and drains into the right atrium through coronary sinus that becomes dilated consequently. Ultrasound imaging provided detailed visualization of both anomalies and their concurrent existence leading to this rare prenatal diagnosis. This copresence is clinically significant due to its potential implications for fetal cardiovascular development and associated genetic conditions.

Keywords

ARSA - fetal echocardiography - PLSVC - power Doppler - ultrasound

An ultrasound scan revealed a rare concurrence of aberrant right subclavian artery (ARSA) and persistent left superior vena cava (PLSVC) in a fetus at 22 weeks of gestation. An ARSA is a vascular anatomic variant in which the right subclavian artery arises aberrantly from the aortic arch, typically passing behind the esophagus. It is present in 0.4 to 1.8% of the general population. A PLSVC, a congenital venous anomaly, is observed in approximately 0.3 to 0.5% of the population and represents an alternative drainage route for the left brachiocephalic vein into the coronary sinus.

In this case, prenatal imaging using 2D and Doppler ultrasound demonstrated an ARSA originating as the fourth vessel from the aortic arch and coursing posterior to the trachea and esophagus. The PLSVC was visualized as an additional vessel on the left side of the ductus arch in the three-vessel view. It was seen running caudally to connect with the coronary sinus, which was consequently dilated. Both anatomic variants are considered hemodynamically insignificant but carry clinical importance due to their association with genetic syndromes such as Down's syndrome and 22q11.2 deletion syndrome.[1]

In the present case, we have demonstrated the chief findings of the fetal heart. The dilated coronary sinus was evident in the apical “four-chamber view” of the fetal heart ([Fig. 1]). The presence of the PLSVC along with the right superior vena cava (RSVC) and ARSA was clearly seen in the “three-vessel trachea (3 VT) view” ([Fig. 2]). The ARSA was well visualized and confirmed during power Doppler scan at “3 VT view” ([Fig. 3]). All vessels were picked up in a blue monochrome as there is no information about the direction of blood flow in this power Doppler mode. For purposes of teaching, we have edited the image to change the color from blue to red for the PSLVC and RSVC to demonstrate the opposite direction of blood flow ([Fig. 4]). Finally, we present a collage of 2D, power Doppler, and 4D spatiotemporal image correlation (STIC) rendered images to show the case in one frame ([Fig. 5]).

Fig. 1 Grayscale ultrasound image of the four-chamber view of the fetal heart showing the presence of dilated coronary sinus (CS). Rt, right; Lt, left.

Fig. 2 Grayscale ultrasound image of the three-vessel trachea view of the fetal heart showing the concurrence of the persistent left superior vena cava (LSVC) and an aberrant right subclavian artery (ARSA). AO, aortic arch; LT, left; PA, pulmonary artery; RSVC, right superior vena cava; RT, right; TR, trachea.

Fig. 3 Power Doppler ultrasound image of the three-vessel trachea view of the fetal heart showing the vascular anatomy as in [Fig. 2.]

Fig. 4 Power Doppler ultrasound image (edited) of the three-vessel trachea view of the fetal heart showing the concurrence of the persistent left superior vena cava (LSVC) and an aberrant right subclavian artery (ARSA). AO, aortic arch; PA, pulmonary artery; RSVC, right superior vena cava; TR, trachea.

Fig. 5 Collage image comprising of grayscale, power Doppler, and color spatiotemporal image correlation (STIC) images of the fetal heart showing the same vascular anomaly.

The coexistence of an ARSA and PLSVC in the same patient is rare with few cases documented in the literature. Early detection of these anomalies during anomaly scan or fetal echocardiography can facilitate genetic counseling and prompt further genetic evaluation, as this concurrence may herald a diagnosis of an underlying genetic aberration.[2] [3]

Conflict of Interest

None declared.

• References

• 1 Chen LP, Lai YF, Zhong XH. et al. Predictive value of aberrant right subclavian artery for fetal chromosome aneuploidy in women of advanced maternal age. BMC Pregnancy Childbirth 2021; 21 (01) 148
• 2 Xue H, Zhang L, Yu A. et al. Prenatal genetic analysis of fetal aberrant right subclavian artery with or without additional ultrasound anomalies in a third level referral center. Sci Rep 2023; 13 (01) 3414
• 3 Luo T, Liu S, Ran S, Dong H, Li Y, Ran Q. Associated congenital anomalies and genetic anomalies in fetuses with isolated and non-isolated aberrant right subclavian artery. J Matern Fetal Neonatal Med 2023; 36 (01) 2211705

Publication History

Article published online:
21 April 2025