Right-sided aortic arch
Updates to Article Attributes
Right-sided aortic arch is a type of aortic arch variant characterised by the aortic arch coursing to the right of the trachea. Different configurations can be found based on the supra-aortic branching patterns, with the two most common patterns being the right-sided aortic arch with mirror image branching and the right-sided aortic arch with aberrant left subclavian artery (ALSA).
Epidemiology
A right-sided aortic arch is thought to occur in approximately ~0.1% (range 0.05-0.2%) of the population.
Pathology
Classification
Right-sided arches can be divided into at least three types (please note that the numbering of the types varies from publication to publication and as such the abnormality should be described rather than merely numbered) 1,7,11-13.
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type I: right-sided aortic arch with mirror image branching
- sometimes reported as the most common, accounting for up to 59% of all right sided arches 11. In most of the literature, it is less common than type II 1
- occurs from interruption of the dorsal segment of the left arch between the left subclavian artery and the descending aorta, with regression of the right ductus arteriosus in the hypothetical double aortic arch
- usually associated with cyanotic congenital heart disease which include
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type II: right-sided aortic arch with aberrant left subclavian artery
- common 1, at least accounting for 39.5% of all right sided arches 11
- associated with Kommerell's diverticulum 11
- occurs from interruption of the dorsal segment of the left arch between the left common carotid and left subclavian arteries with regression of the right ductus arteriosus in the hypothetical double aortic arch
- rarely produces symptoms and is usually incidental although can rarely cause oesophageal and/or tracheal compression 10
- rarely associated with other cardiovascular abnormalities
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type III: right sided aortic arch with isolation of the left subclavian artery 1,6
- most rare type: 0.8% 11
- results from interruption of the left arch at two levels, with one level between the left common carotid and left subclavian arteries and the other level distal to the attachment of the left ductus
- may be associated with congenital subclavian steal syndrome and vertebrobasilar insufficiency
- can be rarely associated with congenital heart disease
Radiographic features
Plain radiograph
- left aortic contour is absent
- tracheal bowing to the left at the level of the right aortic arch
- soft tissue indentation on the right side of the distal trachea
- right sided descending aorta
The right arch is often seen as high riding and projecting as a mass in the right paratracheal region 4.
CT/MRI
Cross-sectional imaging with CT or MRI allows direct visualisation of arch anatomy and with dedicated angiographic techniques (MRA or CTA) excellent demonstration of the lumen can be achieved.
-<li>occurs from interruption of the dorsal segment of the left arch between the left subclavian artery and the descending aorta, with regression of the right ductus arteriosus in the hypothetical double aortic arch </li>- +<li>occurs from interruption of the dorsal segment of the left arch between the <a title="Subclavian artery" href="/articles/subclavian-artery">left subclavian artery</a> and the <a title="Descending aorta" href="/articles/descending-aorta">descending aorta</a>, with regression of the right <a title="Ductus arteriosus" href="/articles/ductus-arteriosus">ductus arteriosus</a> in the hypothetical double aortic arch </li>
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