Anomalous Origin of the Right Subclavian Artery from the Right Pulmonary Artery in a Patient with d-Transposition of the Great Arteries: Diagnosis and Surgical Treatment

Introduction

Anomalous origin of the right subclavian artery (AORSA) from the right pulmonary artery (RPA) is an extremely rare cardiac lesion. Only a few cases have been described.^1-4 We present the case of a newborn who was diagnosed and underwent surgical correction of AORSA from the RPA and d-transposition of the great arteries (d-TGA) in the first hours of life. Despite a force majeure event in the postoperative period, the patient was successfully discharged from the hospital in good condition. We would like to emphasize that we used the clinical presentation and echocardiogram to make the diagnose of AORSA in this patient under critical local conditions. Typically, magnetic resonance imaging (MRI), computed tomography (CT), or angiography are used to make this diagnosis, but these imaging tools were not accessible to us at the time of this case.

Patients and Methods

A full-term 3.18 kg newborn girl, with a prenatal diagnosis of d-TGA and intact ventricular septum was delivered by cesarean section. The patient had severe hypoxia due to a restrictive foramen ovale. The patient was intubated and urgently taken for a balloon atrial septostomy. Of note, the right upper extremity and shoulder had a distinctly demarcated pink appearance while the rest of the body remained deeply cyanotic (Figure 1). Right upper extremity oxygen saturation was 92%, left upper and lower extremity was 40%. Transthoracic echocardiogram (TTE) confirmed the prenatal diagnosis of d-TGA and revealed AORSA from the RPA (Figure 2). The patient was urgently taken to the operating room given the low saturations and a progressive increase of lactate level caused by ineffective atrial septostomy. The arterial switch operation was performed and the AORSA was reimplanted into the right common carotid artery (Figure 3).

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Figure 1.

Clinical manifestation immediately after birth: the right arm and shoulder demonstrated a well-demarcated pink appearance and the rest of the body remained deeply cyanotic.

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Figure 2.

High left parasternal acoustic window. Short axis view of the heart at the level of the great arteries. Aorta (Ao) anterior to the main pulmonary artery (MPA). Anomalous origin of the right subclavian artery (RSA) from the right pulmonary artery (RPA) is shown. LA, left atrium; SVC, superior vena cava.

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Figure 3.

Intraoperative image of transposition of the great arteries with anomalous origin of the right subclavian artery (AORSA) from the right pulmonary artery (RPA). Ao, aorta; PA, pulmonary artery; RA, right atrium; RPA, right pulmonary artery; RV, right ventricle.

Results

The infant was extubated on the third day after the surgical procedure. Although our hospital sustained a missile attack, the postoperative course for our patient was uncomplicated. The patient was transferred to another unit of our hospital and successfully discharged on the 13th postoperative day.

Comment

The combination of d-TGA with AORSA is an extremely rare combination of congenital anomalies.^1-4 In our case, the prenatal echocardiogram did not detect the very rare AORSA from the right pulmonary artery. Only on retrospective analysis of the fetal echocardiogram were we able to make the diagnosis [Figure 4]. The dramatic skin tone difference of the right upper extremity saturation in this patient with d-TGA was key to suspicion of AORSA from the RPA. According to our echocardiogram protocol, we routinely examine the origins of the brachiocephalic artery. In the described patient, the origin of the RSA was not detected in a typical anatomical position, but visualized during subsequent further examination.

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Figure 4.

Fetal echocardiogram, which was retrospectively reviewed. Transverse view with color Doppler imaging of the upper mediastinum in a 36-week gestational-age fetus with d-TGA. The origin of the right subclavian artery (RSA) from the main pulmonary artery (MPA) is shown (*). The ductus arteriosus (DA) had a torturous course. LV, left ventricle; SVC, superior vena cava.

Diagnosis of this cardiac lesion is complicated and usually made using CT, MRI, or angiography. In some cases the diagnosis may have a significant influence on the treatment strategy. ¹ Due to unstable patient and local hospital conditions, we had no opportunity to perform cross-sectional imaging. The patient was taken to surgery in the first few hours of life using our previously published operative approach. ⁵ There are two potential surgical strategies for AORSA; ligation and reimplantation.^4,6,7 We have preferred reimplantation to ligation of the RSA to prevent late subclavian steal syndrome.

In conclusion, clinical signs and echocardiogram images alone may be sufficient to make the correct diagnosis of this rare anomaly especially in critical patients with critical local conditions.