aka Cardiovascular Curveball 004
A 26 year-old man presented to the ED with chest pain, He tripped on some steps and the right-side of his chest collided with the handrail.This is his chest radiograph:
What are the chest radiograph findings?
There is a right-sided aortic arch.
- The trachea is deviated to the left of the midline rather than the right.
- There is no evidence of traumatic injury or situs inversus.
- About 1 in 100,000 people have a right-sided aorta. It occurs during embryological development when the left 4th branchial arch involutes and the right remains, rather than vice versa.
- Right-sided aortic arch can simply be mirror image of a normal left-sided arch, in which case situs inversus may also be present. Alternatively, the right-sided arch may give rise to a left subclavian artery that passes leftwards behind the esophagus, or the arch may cross over into a normal left-sided descending thoracic aorta.
What is the significance of this radiographic finding?
Right sided aortic arches are asymptomatic if they occur in the absence of other cardiovascular abnormalities.
If a child has this finding and presents with respiratory distress or dysphagia what should be suspected?
Obstruction from a vascular ring encircling and constricting the trachea and /or oesophagus.
- For instance, a ring forms around the trachea and oesophagus when a left-sided ligamentum arteriosum connects the left pulmonary artery and a retroesophageal left subclavian artery arsing from the right-sided aortic arch.
- This can mimic croup or recurrent respiratory tract infections – the diagnosis requires a high index of suspicion.
- Bronchoscopy and barium esophagraphy help define the extent of airway or oesophageal compression.
- Echocardiography and/or cardiac catheterisation may also be used to define the nature of any cardiovascular anomalies associated with the vascular ring. CT or MRI may also be performed.
- The ring can be released by division of the ligamentum arteriosum.
What is the diverticulum of Kommerell?
The diverticulum of Kommerell is a dilated pouch at the aortic origin of the retroesophageal left subclavian artery.
- It is formed from the remnant of the involuted left branchial arch.
- Its presence makes the vascular ring tighter, increasing compression of the trachea and oesophagus.
- Thus, right-sided aortic arches that have vascular rings associated with a diverticulum of Kommerell are more likely to be symptomatic.
LITFL Further Reading