Circumflex aorta is a rare aortic arch anomaly caused by retroesophageal crossing of the aorta to the contralateral side. A vascular ring is formed when a ductus or ligamentum arteriosum contralateral to the aortic arch connects the descending aorta to the pulmonary artery.
Like other vascular rings, this anomaly can cause 1-4:
- wheezing or stridor
- frequent respiratory tract infections
Right circumflex aorta develops when there is regression of the left fourth branchial arch and persistence of the left ductus arteriosus and left dorsal aorta. Left circumflex aorta develops from regression of the right fourth branchial arch with persistence of the right ductus arteriosus and right dorsal aorta 2,3.
A right circumflex aorta is more common than a left circumflex aorta.
Frontal chest radiograph may show nonspecific mediastinal widening. On lateral view, the retroesophageal aorta can be seen as a mass-like density displacing the trachea anteriorly.
Oesophagram can demonstrate an impression on the esophagus at the side of the aortic arch and posteriorly where the aorta crosses the midline.
CT and MRI
CT and MRI can demonstrate the aorta crossing the midline posteriorly to descend to the contralateral side.
Treatment and prognosis
Surgery is the definitive treatment for this anomaly. Division of the ductus or ligamentum arteriosum is usually not enough to relieve the compression produced by the retroesophageal aorta. Patients may need to undergo aortic uncrossing, wherein the retroesophageal aorta is transected, mobilized and anastomosed to the ascending aorta anterior to the airway 4.
Possible considerations include:
- 1. Shuford WH, Sybers RG, Gordon IJ, Baron MG, Carson GC. Circumflex retroesophageal right aortic arch simulating mediastinal tumor or dissecting aneurysm. (1986) AJR. American journal of roentgenology. 146 (3): 491-6. doi:10.2214/ajr.146.3.491 - Pubmed
- 2. Hanneman K, Newman B, Chan F. Congenital Variants and Anomalies of the Aortic Arch. Radiographics : a review publication of the Radiological Society of North America, Inc. 37 (1): 32-51. doi:10.1148/rg.2017160033 - Pubmed
- 3. Priya S, Thomas R, Nagpal P, Sharma A, Steigner M. Congenital anomalies of the aortic arch. (2018) Cardiovascular diagnosis and therapy. 8 (Suppl 1): S26-S44. doi:10.21037/cdt.2017.10.15 - Pubmed
- 4. Backer CL, Mongé MC, Russell HM, Popescu AR, Rastatter JC, Costello JM. Reoperation after vascular ring repair. (2014) Seminars in thoracic and cardiovascular surgery. Pediatric cardiac surgery annual. 17 (1): 48-55. doi:10.1053/j.pcsu.2014.01.001 - Pubmed