Isolated Left Subclavian Artery, Complete Atrioventricular Block, and Tricuspid Atresia in a Neonate

Prenatal ultrasound findings, genetic testing, and literature review of Isolated left subclavian artery

BACKGROUND

The occurrence of Isolated left subclavian artery (ILSA) is relatively rare, ILSA is caused by the persistence of the dorsal segment of the sixth left arch, with regression of the fourth arch artery and interruption of the left dorsal aorta at the distal end of the seventh intersegmental artery on the left side during embryonic development. The left subclavian artery is connected to the pulmonary artery through an arterial duct, which can be closed or unobstructed. This abnormality can lead to congenital subclavian steal syndrome and vertebrobasilar artery insufficiency.

CASE PRESENTATION

We reported three fetuses with ILSA and intracardiac malformation. Among them, one case was suspected to be diagnosed with ILSA by echocardiography, while the other two cases were not diagnosed, but were accidentally discovered during autopsy. We have also conducted a literature review of its prenatal screening, diagnosis, management, and outcomes. Our three cases were tested by WES-Trio (whole exome sequencing). Worldwide, the ILSA cases reported in English literature have not been detected by WES. And likely pathogenic results were found in our two cases. Although it could not explain the intracardiac malformation we found, it will help to explore the etiology in the future.

CONCLUSIONS

Prenatal echocardiography detection and diagnosis of ILSA is a new challenge, which has different effects on the prognosis of the fetus. When finding intracardiac malformation with right aortic arch, we need to perform an unconventional view of ultrasound scanning and combine with CDFI to find the origin of the left subclavian artery. Although we cannot find the cause of the disease temporarily, but our genetic results can help prenatal genetic counseling.

Clinical and imaging characteristics of isolated subclavian artery in pediatric patients

OBJECTIVES

To describe clinical and imaging characteristics of an isolated subclavian artery (ISA) in pediatric patients.

BACKGROUND

ISA is a rare congenital aortic arch anomaly defined as a loss of connection between the subclavian artery and aorta. The clinical manifestations and complications of ISA in children are unclear.

METHODS

This retrospective study included clinical and imaging data of ISA patients younger than 18 years whose data were recorded in the electronic radiology database during January 2006-August 2019.

RESULTS

Of 102 enrolled patients, 59 had been diagnosed in the first year of life. The majority of the patients also had congenital heart diseases, of which tetralogy of Fallot was the most common. The vertebral artery and collateral branch of the descending aorta served as blood flow supplies in 94 and 8 patients with ISA, respectively, as confirmed using computed tomography or magnetic resonance imaging. However, the blood supply did not influence the development of ISA. Eleven patients exhibited mild or moderate stenosis of the ISA, although only two exhibited coldness or a blood pressure gradient in the upper extremities. These two symptomatic patients also presented with patent ductus arteriosus, and this association was significant (P = 0.008).

CONCLUSION

ISA management is often determined based on symptoms and associated congenital heart diseases. The ISA is prone to stenosis in patients with ipsilateral patent ductus arteriosus. We recommend early surgical ligation or percutaneous closure of the ductus arteriosus in patients with ISA.

Isolation of the left subclavian artery in an infant with tetralogy of Fallot, right aortic arch and DiGeorge syndrome. Echocardiographic diagnostic case study

We present a case of a 6-month-old infant with an isolated left subclavian artery coexistent with right-sided aortic arch, tetralogy of Fallot and DiGeorge syndrome, with an emphasis on echocardiographic detection of this extremely rare anomaly. Specific difficulties related to echocardiographic visualization of abnormally coursing artery were a result of significantly limited ultrasonographic access due to the absence of thymus and a very close proximity of the left subclavian artery and left common carotid artery, mimicking a normal brachiocephalic trunk, which is usually present in patients with right-sided aortic arch. Precise analysis of the course of carotid and vertebral arteries as well as the nature and direction of flow in these vessels (particularly in the left vertebral and subclavian artery) suggested ductal rather than aortic origin of the left subclavian artery. Precise delineation of anatomical relationships between major arteries prior to surgical closure of the arterial duct was necessary to prevent potential postoperative ischemia of the left upper extremity; therefore the diagnosis was completed with CT angiography.

We present a case of a 6-month-old infant with an isolated left subclavian artery coexistent with right-sided aortic arch, tetralogy of Fallot and DiGeorge syndrome, with an emphasis on echocardiographic detection of this extremely rare anomaly. Specific difficulties related to echocardiographic visualization of abnormally coursing artery were a result of significantly limited ultrasonographic access due to the absence of thymus and a very close proximity of the left subclavian artery and left common carotid artery, mimicking a normal brachiocephalic trunk, which is usually present in patients with right-sided aortic arch. Precise analysis of the course of carotid and vertebral arteries as well as the nature and direction of flow in these vessels (particularly in the left vertebral and subclavian artery) suggested ductal rather than aortic origin of the left subclavian artery. Precise delineation of anatomical relationships between major arteries prior to surgical closure of the arterial duct was necessary to prevent potential postoperative ischemia of the left upper extremity; therefore the diagnosis was completed with CT angiography.