The Clinical Spectrum of Kommerell's Diverticulum in Adults with a Right-Sided Aortic Arch: A Case Series and Literature Overview

Abstract

Background: Kommerell's diverticulum is a rare vascular anomaly characterized as an outpouch at the onset of an aberrant subclavian artery. In the variant of a right-sided aortic arch, the trachea and esophagus are enclosed dorsally by the arch. In the configuration of an aberrant left subclavian artery, a Kommerell's diverticulum and persisting ductus arteriosus or ductal ligament enclose the lateral side, forming a vascular ring which may result in (symptomatic) esophageal or tracheal compression. Spontaneous rupture of an aneurysmatic Kommerell's diverticulum has also been reported. Due to the rarity of this condition and underreporting in the literature, the clinical implications of a Kommerell's diverticulum are not well defined.

Case summary: We describe seven consecutive adult patients with a right-sided aortic arch and an aberrant course of the left subclavian artery (arteria lusoria), and a Kommerell's diverticulum, diagnosed in our tertiary hospital. One patient had severe symptoms related to the Kommerell's diverticulum and underwent surgical repair. In total, two of the patients experienced mild non-limiting dyspnea complaints and in four patients the Kommerell's diverticulum was incidentally documented on a computed tomography (CT) scan acquired for a different indication. The size of the Kommerell's diverticulum ranged from 19 × 21 mm to 30 × 29 mm. In the six patients that did not undergo surgery, a strategy of periodic follow-up with structural imaging was pursued. No significant growth of the Kommerell's diverticulum was observed and none of the patients experienced an acute aortic syndrome to date.

Discussion: Kommerell's diverticulum in the setting of a right-sided aortic arch with an aberrant left subclavian artery is frequently associated with tracheal and esophageal compression and this may result in a varying range of symptoms. Guidelines on management of Kommerell's diverticulum are currently lacking. This case series and literature overview suggests that serial follow-up is warranted in adult patients with a Kommerell's diverticulum with small dimensions and no symptoms, however, that surgical intervention should be considered when patients become symptomatic or when the diameter exceeds 30 mm in the absence of symptoms.

Keywords: Kommerell’s diverticulum; anomalous left subclavian artery; arteria lusoria; esophageal compression; right sided aortic arch; tracheal compression.

Figure 1

(A) Schematic overview of early development. Embryological segments are superimposed on the developing vascular system of the cardiac outflow tract. The vascular system evolves from an initially almost symmetrical bilateral system, into an asymmetrical system. Structures relevant to development of the outflow tract arteries are indicated. (B) Left sided aortic arch. The right 4th pharyngeal arch artery (PAA) and beta-segment now form the base of the right subclavian artery, connecting it to the aorta via the brachiocephalic artery. The right alpha-segment has regressed. (C) Left aortic arch with an aberrant right subclavian artery. Due to deficiency of the right 4th PAA (asterisk *), the proximal part of the right subclavian artery is deficient, and an aberrant right subclavian artery is connected distally to the aorta descendens via a persisting right alpha-segment. (D) Right aortic arch with an aberrant right subclavian artery. In this case, the left 4th PAA is deficient (asterisk *) and the aberrant left subclavian artery is connected to the aorta descendens via a persisting left alpha-segment. Abbreviations in the figure: α, alpha-segment; aLSA, aberrant left subclavian artery; Ao desc, descending aorta; Ao sac, aortic sac; aRSA, aberrant right subclavian artery; β, beta-segment; DA, ductus arteriosus; F, foregut (will later form a.o. esophagus and trachea); Lα, left alpha-segment, LCA, left carotid artery; LSA, left subclavian artery; Pu, pulmonary trunk; Rα, right alpha-segment; RCA, right carotid artery; RSA, right subclavian artery. III, IV and VI, 3rd, 4th and 6th pharyngeal arch arteries (PAA) respectively. Color coding: Grey, ascending aorta; green, carotid arteries, derived form 3rd PAA; purple, aortic B segment (in between carotid and subclavian artery, derived from 4th PAA, olive green, left subclavian arteries (derived from 7th intersegmental arteries); dark brown, descending aorta; dark pink, alpha-segment; light pink, beta-segment. Figures are modified with permission from Molin et al. Cardiovasc Res. 2002 [11] and Molin et.al Birth Defects Res A Clin Mol Teratol. 2004 [12].

Figure 2

A schematic representation of the embryological aortic segments involved in development of a Kommerell’s diverticulum. Panel (A–D): Different views of 3D reconstructions based on computed tomography angiography (CTA) images of a patient with a right-sided aortic arch and an aberrant left subclavian artery. Colors superimposed on the figures indicate segments derived from the embryological pharyngeal arch arteries (PAA) and other embryological aortic segments. Color coding: Grey: ascending aorta; green: carotid arteries, derived from 3rd PAA; purple: aortic B segment (in between carotid and subclavian artery, derived from 4th PAA); olive green: subclavian arteries (derived from 7th intersegmental arteries); dark brown: descending aorta; dark pink: alpha-segment; light pink: beta-segment. Colors and segments are derived from Molin et al. Cardiovasc Res. 2002 [11], and Molin et al. Birth Defects Res A Clin Mol Teratol. 2004 [12]. (A) Anterior view. Note the right-sided position of the arch in relation to trachea and esophagus. Upstream in the aorta, the following aortic arch tributaries can be encountered: left carotid artery (LCA), right carotid artery (RCA), right subclavian artery (RSA) and an aberrant left subclavian artery (aLSA). (B) Right lateral view indicating the embryonic aortic segments of the right aortic arch. (C) Posterior view and (D) left lateral view. The aLSA connects to a dilated embryonic beta-segment (arrow), that forms the base of a Kommerell’s diverticulum (KD). The asteriks * indicates where the location of the left 4th PAA (that is missing here) would have been in case of a double aortic arch. As the 4th PAA borders the beta-segment, the the segment indicating the dilated beta-segment, may also comprisee part of an incompletely regressed left 4th PAA. α, alpha-segment; Ao asc, ascending aorta; Ao desc, descending aorta; aLSA, aberrant left subclavian artery; β, beta-segment; Es, esophagus; LB, left bronchus; LCA, left carotid artery; LSA, left subclavian artery; KD, Komerell’s diverticulum; RB, right bronchus; RCA, right carotid artery; RSA, right subclavian artery; Tr, trachea.

Figure 3

Patient 1. Panel (A) shows a CT-image reconstructed with global illumination rendering (iGIR) (Vitrea^®, Vital Images) in a anterolateral orientation depicting a right-sided aortic arch with an aberrant left subclavian artery. Panel (B) shows a close up of the oblique posterior view of a Kommerell’s diverticulum as the onset of the aberrant left subclavian artery. Panel (C) is an axial reconstruction depicting the anatomical relationship between the aortic arch, Kommerell’s diverticulum and an aberrant brachiocephalic vein which encircle the trachea resulting in mild compression. Panel (D) is a minimum intensity projection of the trachea showing mild external compression. ASA, aberrant subclavian artery; CCA, common carotid artery.

Figure 4

Patient 2. Panel (A) shows a lateral computed tomography reconstruction depicting a right-sided aortic arch with an aberrant left subclavian artery. The zoomed posterolateral reconstruction in panel (B) shows that the aberrant left subclavian artery is arising from a Kommerell’s diverticulum. Panel (C) is a coronal reconstruction that reveals tracheal compression. The axial 3D cross-section (panel (D)) shows partial posterior compression of the trachea which was secondary to tracheal bowing and not directly to compression by the vascular structures. ASA, aberrant subclavian artery; CCA, common carotid artery; SA, subclavian artery.

Figure 5

Patient 3. Panels (A–C) pre-operative imaging, panels (D–F) post-operative imaging. Panel (A) shows the axial reconstructions illustrating a right-sided aortic arch, aberrant left subclavian artery and a Kommerell’s diverticulum compressing the trachea and esophagus. Panel (B) shows the volume rendering images and panel (C) depicts the compressed trachea. Panel (D) shows the post-operative result after surgical resection of the Kommerell’s diverticulum in axial reconstructions and panel (E) in volume rendered reconstructions. Panel (F) depicts the trachea, illustrating some increase in tracheal dimensions. KD, Kommerell’s diverticulum.

Figure 6

Patient 4. Panel (A) shows a lateral reconstruction depicting a right-sided aorta and an aberrant left subclavian artery with Kommerell’s diverticulum. Panel (B) shows the tracheal compression in isolation. Panel (C) provides a volume rendered axial reconstruction and panel (D) a standard axial reconstruction. CCA, common carotid artery; SA, subclavian artery.

Figure 7

Patient 5. Panel (A) shows a posterolateral view depicting a right-sided aortic arch and an aberrant left subclavian artery with a Kommerell’s diverticulum. The axial (panel (B)) and oblique sagittal (panel (C)) lateral 3D volume rendering reconstructions reveal that the Kommerell’s diverticulum causes esophageal compression. Panel (D) shows the axial reconstruction and in panel (E) the mild tracheal compression is viewed in isolation. CCA, common carotid artery; SA, subclavian artery.

Figure 8

Patient 6. Panel (A) shows a posterolateral view of a right-sided aortic arch with mirror imaging branching and an isolated Kommerell’s diverticulum compressing the trachea (panel (B)) by the formation of a vascular ring (panel (C)). Panel (D) shows the axial reconstruction. CCA, common carotid artery; SA, subclavian artery.

Figure 9

Patient 7. Panel (A) shows a posterior view of the descending thoracic aorta, right-sided aortic arch and Kommerell’s diverticulum as offset for an aberrant left subclavian artery. In panel (B) the short axis configuration is depicted showing mild tracheal compression. Panel (C) shows the axial reconstruction and panel (D) provides the trachea in isolation. ASA, aberrant subclavian artery; CCA, common carotid artery; SA, subclavian artery.