Aortic Arch Pattern and Embryology — #4 Right Aortic Arch with Vascular Ring

Date
October 27, 2025
URL
https://x.com/WithAScalpel/status/1982780764711211069
Categories
Vascular Ring

Aortic Arch Pattern and Embryology — #4 Right Aortic Arch with Vascular Ring

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Definition and Core Anatomy

A right aortic arch (RAA) forms a complete vascular ring when it coexists with an aberrant left subclavian artery (LSCA) arising from a posterior Kommerell diverticulum and a left-sided ductus arteriosus/ligamentum arteriosum inserting on the left pulmonary artery. Together, these structures encircle the trachea and esophagus, producing stridor, wheeze, recurrent infections, and/or dysphagia (dysphagia lusoria) [1, 2].

Embryologic Mechanism

This configuration reflects asymmetric remodeling of the pharyngeal arch system: persistence of the right fourth arch and right dorsal aorta establishes a right-sided arch and descending aorta, while regression of the left fourth arch leaves the distal left dorsal aorta to persist as a posterior diverticulum. With the left seventh intersegmental artery, this forms an aberrant LSCA coursing retroesophageally. Persistence of the left sixth arch as a ductus/ligamentum completes the circumferential ring from the LSCA side to the left pulmonary artery [1, 3, 4].

Variants and Relationships

The typical ring is RAA + aberrant LSCA + left ductus/ligamentum. In contrast, mirror-image RAA with a right ductus usually does not create a ring. Size and take-off angle of a Kommerell diverticulum influence compressive symptoms and the need for adjunct procedures [4–6]. While mirror-image RAA often accompanies conotruncal lesions, the aberrant-LSCA pattern has fewer intracardiac defects; nevertheless, the 22q11.2 microdeletion should be considered in the broader RAA differential [7].

Diagnostic Approach

  • Transthoracic echocardiography confirms arch sidedness, branch sequence, and screens for intracardiac disease [2].
  • CT angiography or MR angiography defines the arch, retroesophageal LSCA, Kommerell diverticulum, and tracheoesophageal relationship; dynamic imaging and/or bronchoscopy evaluate tracheomalacia [1, 3, 8].
  • Barium esophagram can demonstrate a characteristic posterior indentation from a retroesophageal LSCA in classic cases [8, 9].

Surgical Principles

Symptomatic patients—and asymptomatic infants with a large diverticulum—are offered repair. Through a left thoracotomy (or thoracoscopic approach in selected centers), key steps are:

  1. Divide the left ductus/ligamentum to break the ring.
  2. Address the Kommerell diverticulum with generous resection or posterior wall reduction to eliminate a compressive pouch.
  3. Manage the LSCA when posterior tethering or hypoperfusion is likely: reimplantation/transposition of the LSCA to the left carotid or aorta prevents residual compression and subclavian steal [1, 5, 6, 10].

    4. Meticulous protection of the left recurrent laryngeal and phrenic nerves and tailored mediastinal decompression (lysis of fibrous bands, gentle esophageal mobilization) help reduce persistent symptoms due to baseline tracheobronchomalacia [2].

Outcomes and Practical Pearls

Across contemporary series, ductal division with diverticulum resection—plus LSCA revascularization when indicated—yields excellent symptom relief with low complication rates; residual morbidity most often reflects pre-existing airway malacia rather than recurrent vascular compression [2, 9, 10]. Practical points: (i) confirm the complete ring on preoperative cross-sectional imaging; (ii) size/angulation of the diverticulum predicts the need for resection and LSCA translocation; (iii) mirror-image RAA without an aberrant LSCA or contralateral ductus is unlikely to be a ring—seek alternative causes for symptoms [1, 4].

References

[1] Backer CL, Mongé MC, Popescu AR, Eltayeb O, Rastatter JC, Rigsby CK. Vascular rings. Semin Pediatr Surg. 2014;23(4):181-189.

[2] Ruzmetov M, Vijay P, Rodefeld MD, Rouse S, Turrentine MW, Brown JW. Follow-up of surgical correction of vascular rings: a 36-year experience. J Pediatr Surg. 2009;44(6):112-117.

[3] Kellenberger CJ. Aortic arch malformations. Pediatr Radiol. 2010;40(6):876-884.

[4] Cinà CS, Althani H, Pasenau J, Abouzahr L. Kommerell’s diverticulum and aneurysmal right-sided aortic arch: a case and review. J Vasc Surg. 2004;39(1):131-139.

[5] Kouchoukos NT, Masetti P. Aberrant subclavian artery and Kommerell diverticulum: surgical treatment with subclavian revascularization. J Thorac Cardiovasc Surg. 2007;133(4):888-892.

[6] Ota T, Okada K, Takanashi S, Yamamoto S, Okita Y. Surgical treatment for Kommerell’s diverticulum. J Thorac Cardiovasc Surg. 2006;131(3):574-578.

[7] McElhinney DB, Clark BJ 3rd, Weinberg PM, et al. Association of chromosome 22q11 deletion with isolated anomalies of aortic arch laterality and branching. J Am Coll Cardiol. 2001;37(8):2114-2119.

[8] Yoo SJ, Goo HW, Park IS, et al. MR imaging of vascular rings and slings. Radiographics. 1999;19(2):e40.

[9] Licari A, Manca E, Rispoli GA, Mannarino S, Pelizzo G, Marseglia GL. Congenital vascular rings: a practical approach for management. Paediatr Respir Rev. 2015;16(4):308-314.

[10] Shinkawa T, Greenberg SB, Jaquiss RD, et al. Management of Kommerell diverticulum associated with right aortic arch and aberrant left subclavian artery in children. Ann Thorac Surg. 2012;93(3):976-981.