Right aortic arch – aberrant left subclavian artery

• Embryology

• Left: Schematic diagram depicting the segments of the pharyngeal arch system that regress (shown in black) in order for the development of a right aortic arch with aberrant left subclavian artery. Right: Mature anatomy of a vascular ring formed by a right aortic arch with an aberrant left subclavian artery arising from a retroesophageal diverticulum with a left-sided ligamentum arteriosum to the left pulmonary artery.

Causes • Factors responsible for aberrant

development of the aortic arch and its branches, as occurs in patients with vascular rings, have not been clearly identified, and the pathogenesis of these anomalies remains unclear. Vascular rings with a right aortic arch typically occur without associated cardiovascular defects, although other lesions may be present, and accordingly are not usually found as part of a syndromic complex.

• In a study from the author's institution, band 22q11 deletions Aortic arch anomalies, including vascular rings, have been induced in various animal models, such as neural crest–ablated chicks, mice with disrupted genes for the endothelin-A receptor or endothelin-converting enzyme, and others. The mechanisms and significance of these models for understanding the development of vascular rings have not been elucidated.

• In a study from the author's institution, band 22q11 deletions were found in 8 of 34 patients (24%) with a right aortic arch, vascular ring, and no other cardiac defects.2 The deletion was found in 8 of 29 patients (28%) with a right arch, aberrant left subclavian artery, and left-sided ductus from the aberrant left subclavian artery to the left pulmonary artery and in none of 5 patients with a right arch, mirror-image branching of the brachiocephalic vessels, and a left ductus from the descending aorta to the left pulmonary artery.

– This chromosomal anomaly is associated with aortic arch anomalies in patients with other forms of conotruncal heart disease as well as other isolated vascular abnormalities, and band 22q11 deletion is likely an important etiologic factor in vascular rings with a right aortic arch.

– Although band 22q11 deletion was not found in 5 patients with a vascular ring formed by a mirror-image right arch and a left ductus from the descending aorta, this sample is too small to rule out a potential association.

– In general, most band 22q11 deletions arise de novo, and no recognizable inheritance pattern is present.

Report case

G3P0, 32years old, no significant history, 34 weeks

pregnancy

Transverse abdominal view (Ao is in front/left of the spine)

3 vessel view (descendent Ao is in right of the spine)

4 chamber view - descendent Ao in the right

4 ch. view - dAo is in front of the spine

Ao arch, ductus arteriosus whith a posterior connection (“U shape” orientated post and right), around the esophagus and tracheea

Vascular ring: (1- double aortic arch or 2 - right aortic arch with aberant left subclavian artery)

Pa = pulmonary artery + ductus arteriosusAo = ascendant portion of aortaArch = right aortic archSVC = superior vena cava /? = a retroesophageal diverticulum (diverticulum of Kommerell) (behind of esophagus and tracheea) aberrant origin of the left subclavian artery

3vessel view to arch view

Aortic Arch is in right side, perpediculary on the spine

5 chambers view (color Doppler)

Associated cardiovascular anomalies:Vascular rings, including those with a right aortic arch, usually occur without associated

cardiovascular anomalies. Ventricular septal defect is the most common associated anomaly, although various others have been reported as well.

AP = pulmonary artery + ductus arteriosusAo = ascendent portion of aortadAo = descendent aorta Arch = right aortic arch? = a retroesophageal diverticulum (diverticulum of Kommerell) (behind of esophagus and tracheea)

Right Pulmonary artery