RAA with Aberrant LSCA: From Embryology to Surgical Repair

A right aortic arch with an aberrant left subclavian artery arising from Kommerell’s diverticulum is one of the classic anatomic substrates of a vascular ring. In this configuration, the aortic arch passes to the right of the trachea and esophagus, while the left subclavian artery arises aberrantly from a posterior diverticular remnant and courses retroesophageally toward the left upper extremity [1].

The clinically important point is that this lesion is not only a circumferential vascular ring. It may also produce persistent posterior tracheoesophageal compression from the Kommerell diverticulum and the retroesophageal course of the aberrant left subclavian artery.

When a left-sided ductus arteriosus or ligamentum arteriosum connects the diverticular region to the left pulmonary artery, the trachea and esophagus may become completely encircled.

Therefore, definitive repair should be planned around two goals:

1. Release the vascular ring
2. Eliminate residual posterior compression

In selected patients, this requires more than ligamentum division alone; it may require resection or reduction of Kommerell’s diverticulum and management of the aberrant left subclavian artery.

2. Embryologic Basis

Normal aortic arch development depends on selective persistence and regression of the paired embryonic aortic arches and dorsal aortae.

In right aortic arch with aberrant left subclavian artery:

• The right fourth aortic arch persists and contributes to the right-sided transverse arch.
• The right dorsal aorta persists and maintains continuity between the right arch and descending thoracic aorta.
• The left fourth aortic arch regresses, preventing formation of a normal left-sided aortic arch.
• A remnant of the left dorsal aorta persists near the origin of the aberrant left subclavian artery.
• The left seventh intersegmental artery forms the left subclavian artery.
• Persistence of a left sixth arch derivative forms a left-sided ductus arteriosus, later becoming the ligamentum arteriosum.

The persistent left dorsal aortic remnant forms Kommerell’s diverticulum, from which the aberrant left subclavian artery arises.

This embryologic configuration explains why the aberrant left subclavian artery originates posteriorly and crosses behind the esophagus, rather than arising normally from a left-sided arch.

3. Anatomic Configuration

The usual branching order is:

1. Left common carotid artery
2. Right common carotid artery
3. Right subclavian artery
4. Aberrant left subclavian artery arising from Kommerell’s diverticulum

The aberrant left subclavian artery typically arises as the last branch and courses posterior to the esophagus toward the left arm.

The vascular ring is formed by:

• The right aortic arch on the right side
• The Kommerell diverticulum and aberrant left subclavian artery posteriorly
• The left-sided ductus arteriosus or ligamentum arteriosum on the left side
• The pulmonary artery connection completing the ring anteriorly and inferiorly

This arrangement may compress the trachea, esophagus, or both.

4. Clinical Significance

Symptoms depend on the degree of airway and esophageal compression.

Common manifestations include:

• Stridor
• Recurrent respiratory infections
• Persistent wheezing
• Feeding difficulty
• Choking or vomiting with feeds
• Dysphagia
• Failure to thrive in severe cases

Infants often present with airway symptoms, whereas older children may have more prominent esophageal symptoms.

A key surgical concept is that symptoms may persist after simple ligamentum division if Kommerell’s diverticulum remains large or if the aberrant left subclavian artery continues to exert posterior compression.

5. Surgical Objectives

The goals of repair are:

1. Divide the ligamentum arteriosum to release the ring
2. Remove or reduce Kommerell’s diverticulum when it contributes to compression
3. Eliminate the retroesophageal tethering effect of the aberrant left subclavian artery
4. Preserve left upper extremity perfusion
5. Avoid a residual diverticular stump that may cause persistent symptoms or late dilation

Several contemporary surgical strategies have been described, including ligamentum division alone, diverticulum resection with left subclavian artery translocation or reimplantation, and diverticulum plication or pexy in selected patients [2,3].

6. Operative Concept

6.1 Exposure

Repair is commonly performed through a left thoracotomy, which provides access to:

• Ligamentum arteriosum
• Descending thoracic aorta
• Kommerell’s diverticulum
• Aberrant left subclavian artery
• Left common carotid artery
• Left pulmonary artery region

Careful dissection is required because the operative field is close to the esophagus, thoracic duct, vagus nerve, recurrent laryngeal nerve, phrenic nerve, and sympathetic chain.

6.2 Division of the Ligamentum Arteriosum

The ligamentum arteriosum is identified, controlled, and divided.

This releases the circumferential component of the vascular ring. However, ligamentum division alone may be incomplete if posterior compression from Kommerell’s diverticulum or the retroesophageal left subclavian artery persists.

Thus, the surgeon should not equate “ring division” with “complete decompression” in every patient.

6.3 Resection or Reduction of Kommerell’s Diverticulum

When Kommerell’s diverticulum is prominent, it may be clamped at its base and resected, followed by secure closure of the aortic wall.

The purpose is to remove the posterior vascular mass compressing the trachea and esophagus. This step also avoids leaving a residual diverticular pouch.

Some approaches use plication or pexy of the diverticulum rather than formal resection, aiming to reduce posterior compression while avoiding more extensive reconstruction in selected patients [4].

6.4 Left Subclavian Artery Reimplantation or Translocation

After mobilization, the aberrant left subclavian artery may be divided from its abnormal origin and reimplanted into the left common carotid artery.

This strategy has three purposes:

1. It preserves antegrade blood flow to the left arm.
2. It removes the retroesophageal course of the left subclavian artery.
3. It prevents persistent posterior tethering behind the esophagus.

The anastomosis is usually performed end-to-side to the left common carotid artery. Technical priorities include avoiding tension, kinking, narrowing, or excessive traction on the carotid artery.

Primary translocation of the aberrant left subclavian artery with removal of the diverticular origin has been reported as an effective strategy for symptomatic vascular rings in children [5].

7. Evidence on Surgical Strategy

The optimal extent of repair remains debated.

A 21-year comparative analysis of 131 patients compared ligamentum division alone with Kommerell diverticulum resection and subclavian translocation. In that cohort, there were no significant differences in perioperative complications, short-term symptom relief, or long-term symptom recurrence between the two strategies [6].

However, other pediatric series suggest that addressing the diverticulum may reduce residual symptoms in selected patients. In a 44-patient study, persistent symptoms occurred in 32% after ligamentum division alone compared with 5% after ligamentum division combined with Kommerell diverticulum plication or pexy [4].

A smaller series comparing division alone with primary translocation reported that all patients in the translocation group remained asymptomatic, whereas several patients in the division-alone group required ongoing medication for residual symptoms [5].

Contemporary reports of early Kommerell diverticulum resection with left subclavian artery revascularization support this more complete anatomic repair in selected children with right aortic arch and aberrant left subclavian artery [7].

Overall, the evidence does not mandate diverticulum resection for every patient. Rather, it supports individualized operative planning based on symptoms, diverticulum size, airway and esophageal compression, and the anatomic relationship of the aberrant left subclavian artery.

8. Why Simple Ring Division May Be Insufficient

A common misconception is that vascular ring repair is complete once the ligamentum arteriosum has been divided.

In right aortic arch with aberrant left subclavian artery from Kommerell’s diverticulum, the pathology may include two distinct components:

1. The ligamentum arteriosum, which completes the circumferential ring
2. The diverticulum and retroesophageal aberrant left subclavian artery, which may continue to compress the tracheoesophageal space

Therefore, simple ligamentum division may release the ring but leave residual posterior compression.

A more complete repair may be appropriate when imaging or intraoperative findings show a prominent diverticulum, significant posterior airway or esophageal compression, or a retroesophageal left subclavian artery that remains tethered.

9. Perioperative Considerations

Preoperative evaluation should define:

• Arch sidedness
• Branching pattern
• Size and morphology of Kommerell’s diverticulum
• Course of the aberrant left subclavian artery
• Relationship to the trachea and esophagus
• Degree of airway compression
• Associated intracardiac anomalies

Computed tomography angiography is especially useful because it clarifies the three-dimensional relationship among the arch, diverticulum, airway, esophagus, and branch vessels.

Postoperative assessment should focus on:

• Respiratory improvement
• Feeding tolerance
• Left arm perfusion
• Vocal cord function when clinically indicated
• Chylothorax
• Phrenic nerve dysfunction
• Residual or recurrent airway symptoms

Reported complications are generally comparable between more limited and more extensive repairs, but chylothorax and phrenic nerve injury remain important complications to consider during surgical planning and postoperative monitoring [4,6].

10. Key Surgical Message

Right aortic arch with aberrant left subclavian artery from Kommerell’s diverticulum is both a vascular ring lesion and a posterior compression lesion.

The operative strategy should therefore be individualized:

• Divide the ligamentum arteriosum to release the ring.
• Resect, plicate, or pexy Kommerell’s diverticulum when it contributes to compression.
• Reimplant or translocate the left subclavian artery when necessary to preserve perfusion and eliminate the retroesophageal course.

The central principle is not simply to open the ring, but to remove all clinically significant sources of tracheoesophageal compression.

References

[1] Tamayo-Espinosa T, Erdmenger-Orellana J, Becerra-Becerra R, Balderrábano-Saucedo N, Segura-Standford B. [Right-side aortic arch with aberrant left subclavian artery and Kommerell's diverticulum. A cause of vascular ring]. Arch Cardiol Mex. 2017. doi:10.1016/j.acmx.2017.03.006.

[2] Luciano D, Mitchell J, Fraisse A, Lepidi H, Kreitmann B, Ovaert C. Kommerell diverticulum should be removed in children with vascular ring and aberrant left subclavian artery. Ann Thorac Surg. 2015. doi:10.1016/j.athoracsur.2015.06.093.

[3] Bidar E, Arrigoni SC, Accord R. Resection of Kommerell diverticulum and reimplantation of aberrant left subclavian artery in right aortic arch vascular ring. Semin Thorac Cardiovasc Surg. 2019. doi:10.1053/j.semtcvs.2018.11.015.

[4] Perkins A, Tomescu A, Knott-Craig CJ, Boston U, Spentzas T, Ramakrishnan K. Aortopexy with plication of Kommerell diverticulum is an effective alternative to diverticulum resection and reimplantation of the aberrant left subclavian artery for surgical management of vascular rings in children. World J Pediatr Congenit Heart Surg. 2025. doi:10.1177/21501351251329912.

[5] Shinkawa T, Greenberg S, Jaquiss R, Imamura M. Primary translocation of aberrant left subclavian artery for children with symptomatic vascular ring. Ann Thorac Surg. 2012. doi:10.1016/j.athoracsur.2011.12.030.

[6] Marsh JC, Muralidaran A, Shen I, Iguidbashian J, Ootaki Y. The impact of Kommerell diverticulum resection on patient outcomes: A 21-year comparative analysis of surgical techniques for vascular rings. JTCVS Open. 2025. doi:10.1016/j.xjon.2025.10.001.

[7] Du XW, Wang H, Chen LQ, Zhang DW, Xu Z, Lu Z, Wang S, Zhang HB. Early resection of Kommerell diverticulum and revascularization in children with right aortic arch and aberrant left subclavian artery. Ann Thorac Surg. 2025. doi:10.1016/j.athoracsur.2025.05.025.