Right-Sided Aortic Arch with Diverticulum of Kommerell and Aberrant Left Subclavian Artery: A Comprehensive Review

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  Right-Sided Aortic Arch with Diverticulum of Kommerell and Aberrant Left Subclavian Artery: A Comprehensive Review

1. Introduction

Right aortic arch with Kommerel's diverticulum and an anomalous left subclavian artery (ALSA) is a rare congenital vascular anomaly that can present with clinical manifestations ranging from asymptomatic to severe airway or esophageal compression.

While often discovered incidentally on CT angiography, diagnosis is crucial due to the risk of progressive symptoms and potential complications, such as aneurysmal degeneration or rupture.

This post discusses the etiology, pathogenesis, pathophysiology, epidemiology, clinical presentation, radiological features, treatment options, and prognosis of this anomaly.

This article is based on a case-based imaging study of a 50-year-old woman who presented with dyspnea on exercise and is based on various CT angiographic findings.

2. Case Presentation

A woman in her 50s presented with exertional dyspnea. CT angiography revealed:

  • Right-sided aortic arch (RAA)

  • Aberrant left subclavian artery arising from the distal aortic arch

  • Bulbous dilatation at the origin of ALSA is consistent with Kommerell diverticulum

  • Mild tracheal compression

  • Irregular narrowing at the ALSA origin

Figure 1. CT angiography, axial view – demonstrates the right-sided aortic arch (RAA) with aberrant course of the left subclavian artery.
Figure 2. CT angiography, coronal view – highlights Kommerell diverticulum’s bulbous origin from the aortic arch.

Figure 3. CT angiography, sagittal view – depicts the spatial relationship between ALSA, trachea, and esophagus.

3. Etiology and Pathophysiology

The right-sided aortic arch results from persistence of the right fourth embryonic aortic arch with regression of the left counterpart.
When associated with an aberrant left subclavian artery, the ALSA arises as the last branch of the arch, passing posterior to the esophagus.

Kommerell diverticulum represents a remnant of the left dorsal aortic root, forming a bulbous origin of the aberrant artery. This diverticulum can enlarge over time, potentially causing compression or evolving into an aneurysm.

4. Epidemiology

  • Aortic arch anomalies: 1–3% of congenital heart defects

  • Right-sided aortic arch: ~0.1% in adults

  • About 50% of RAA cases have aberrant left subclavian arteries

  • Kommerell diverticulum prevalence: ~0.05%

  • ALSA in RAA is less common than an aberrant right subclavian artery in a left aortic arch

5. Clinical Presentation

  • Most patients: asymptomatic

  • Symptomatic cases may present with:

    • Dysphagia lusoria (difficulty swallowing due to vascular compression)

    • Dyspnea or wheezing (airway compression)

    • Chest pain or upper back discomfort

    • Rarely, acute symptoms from aneurysm rupture

6. Imaging Features

CT angiography is the gold standard for evaluating arch anatomy and vascular anomalies.

Right-sided aortic arch subtypes:

  1. Mirror-image branching – often associated with cyanotic congenital heart disease.

  2. Aberrant left subclavian artery (Type II) – commonly associated with Kommerell diverticulum, rarely with other congenital cardiac anomalies.

  3. Isolated left subclavian artery – hypoplastic or disconnected from the aorta.

In this case, Type II RAA with ALSA and Kommerell diverticulum was observed.

7. Treatment

  • Asymptomatic patients: regular imaging follow-up

  • Symptomatic patients:

    • Surgical resection of diverticulum with reimplantation or bypass of ALSA

    • Endovascular stent grafting for aneurysmal Kommerell diverticulum

    • Hybrid procedures combining open and endovascular repair

Early intervention is recommended if:

  • Symptomatic compression occurs

  • Diverticulum diameter exceeds 3–5 cm

  • Rapid aneurysmal enlargement is detected

8. Prognosis

  • Good prognosis if diagnosed early and treated before complications

  • An untreated aneurysmal diverticulum carries a risk of rupture, dissection, or thromboembolism

  • Post-surgical outcomes are generally favorable, with symptom relief and low recurrence rates

Quiz

1. Which embryologic event leads to a right-sided aortic arch?
A. Regression of the right fourth arch
B. Persistence of the right fourth arch and regression of the left fourth arch
C. Persistence of both arches
D. Regression of both arches

2. What is a Kommerell diverticulum?
A. A saccular aneurysm of the abdominal aorta
B. Bulbous origin of an aberrant subclavian artery
C. Congenital stenosis of the subclavian artery
D. Calcified plaque at the aortic arch

3. Which symptom is most commonly associated with a vascular ring from ALSA?
A. Dysphagia lusoria
B. Hemoptysis
C. Syncope
D. Arrhythmia

4. What imaging modality best defines arch anomalies?
A. Chest X-ray
B. CT angiography
C. Echocardiography
D. Plain CT

5. Which is more common: ALSA in RAA or aberrant right subclavian artery in LAA?
A. ALSA in RAA
B. Aberrant right subclavian artery in LAA

Answer & Explanation

1. Answer: B. Explanation: Right-sided aortic arch results from persistence of the right fourth arch and regression of the left.

2. Answer: B. Explanation: It is a remnant of the dorsal aorta causing bulbous dilatation at the origin of an aberrant subclavian artery.

3. Answer: A. Explanation: Compression of the esophagus leads to dysphagia lusoria.

4. Answer: B. Explanation: CT angiography provides detailed anatomical mapping of the aortic arch and its branches.

5. Answer: B. Explanation: Aberrant right subclavian artery in a left aortic arch is more frequent.

Reference

[1] M. T. Adams, M. Wilhelm, N. Singh, and C. Andersen, “Right aortic arch with Kommerell diverticulum: A rare cause of dysphagia,” JAMA Otolaryngol Head Neck Surg., vol. 140, no. 6, pp. 560–562, 2014.
[2] T. C. Bhatt, C. G. Muralidharan, G. Singh, and N. K. Jain, “Kommerell’s diverticulum: A rare aortic arch anomaly,” Med J Armed Forces India, vol. 72, Suppl 1, pp. S80–S83, 2016.
[3] I. S. Ganie, K. Amod, and D. Reddy, “Vascular rings: A radiological review of anatomical variations,” Cardiovasc. J. Afr., vol. 27, no. 1, pp. 30–36, 2016.
[4] M. A. Law and J. Mohan, “Right aortic arches,” StatPearls, Treasure Island, FL: StatPearls Publishing, 2023.
[5] A. Morishita et al., “Surgical treatment for Kommerell’s diverticulum associated with a right-sided aortic arch and an aberrant left subclavian artery: Endovascular or hybrid,” Ann Vasc Dis., vol. 12, no. 2, pp. 228–232, 2019.
[6] M. Y. Mubarak, A. T. Kamarul, and M. D. Noordini, “Right-sided aortic arch with aberrant left subclavian artery from Kommerell’s diverticulum,” Iran J Radiol., vol. 8, no. 2, pp. 103–106, 2011.
[7] S. M. Said et al., “Outcomes of surgical repair of vascular rings and slings in children: A word for the asymptomatic,” Semin Thorac Cardiovasc Surg., vol. 33, no. 2, pp. 492–500, 2021.

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