statdx/docs_md/articles/aberrant-right-subclavian-artery_a20702fe-5409-44a5-a804-cb071023bade.md

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Aberrant Right Subclavian Artery	a20702fe-5409-44a5-a804-cb071023bade	key value 770e1d77-2287-436e-910b-48232afc7842 Prabhakar Rajiah, MBBS, MD, FACR, FRCR, FACC, FAHA, FSCCT key value e915766e-8102-46e4-a33e-c83f8ae12f29 Harold Goerne, MD	name slug treeNodeId Cardiac cardiac fa90100b-619c-430e-8074-b5b9789bab39 name slug treeNodeId Diagnosis diagnosis 5c92cf4f-e9d5-4059-9c13-22255c51c121 name slug treeNodeId Aorta aorta 4d206a6b-1a82-467c-9199-0df25ab749d7 name slug treeNodeId Aberrant Right Subclavian Artery aberrant-right-subclavian-artery null	Cardiac	69195035-5819-4996-b27d-b107c62d7c60	12	01/28/25	Aberrant Right Subclavian Artery	Cardiac, Diagnosis, Aorta, Aberrant Right Subclavian Artery	Aberrant Right Subclavian Artery | STATdx	Aberrant Right Subclavian Artery	DX	true	Cardiac Diagnosis Aorta Aberrant Right Subclavian Artery

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title: "Aberrant Right Subclavian Artery" docid: "a20702fe-5409-44a5-a804-cb071023bade" authors:

• key: "770e1d77-2287-436e-910b-48232afc7842" value: "Prabhakar Rajiah, MBBS, MD, FACR, FRCR, FACC, FAHA, FSCCT"
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• name: "Aberrant Right Subclavian Artery" slug: "aberrant-right-subclavian-artery" treeNodeId: null category: "Cardiac" documentVersionId: "69195035-5819-4996-b27d-b107c62d7c60" imageCount: 12 lastUpdated: "01/28/25" pageDescription: "Aberrant Right Subclavian Artery" pageKeywords: "Cardiac, Diagnosis, Aorta, Aberrant Right Subclavian Artery" pageTitle: "Aberrant Right Subclavian Artery | STATdx" enhancedTitle: "Aberrant Right Subclavian Artery" type: "DX" references: true breadcrumbs:
• "Cardiac"
• "Diagnosis"
• "Aorta"
• "Aberrant Right Subclavian Artery"

---

KEY FACTS

• Terminology

  • Aberrant right subclavian artery (ARSA) as last branch of left-sided aortic arch, isthmus, or proximal descending aorta
  • Course: Retroesophageal 80%; intertracheoesophageal 15%; pretracheal 5%

• Imaging

  • Barium esophagogram shows persistent esophageal narrowing at level of extrinsic compression with oblique course
  • CTA or MRA help to understand origin and course of supraaortic trunks
  • No vascular ring formed by left aortic arch and ARSA
  • Loose vascular ring if ARSA originates from Kommerell diverticulum
  • Complete vascular ring if ARSA with circumflex right descending thoracic aorta with right ductus

• Top Differential Diagnoses

  • Major aortopulmonary collateral arteries (MAPCAs)
  • Right arch with aberrant left subclavian artery
  • Retroesophageal diverticulum

• Pathology

  • Regression of right 4th arch between right subclavian and right common carotid arteries, including right ductus arteriosus

• Clinical Issues

  • Most common congenital aortic arch abnormality (0.5-2.0%)
  • 90-95% asymptomatic; incidental imaging finding
  • Adults: Dysphagia (lusoria), dyspnea, back pain
  • Infants: Cough, stridor, aspiration pneumonia
  • Surgery for symptoms, aneurysm, or large diverticulum

TERMINOLOGY

• Abbreviations

  • Aberrant right subclavian artery (ARSA)

• Synonyms

  • Lusoria artery (arteria lusoria)
  • Incomplete vascular ring

• Definitions

  • Aberrant origin of right subclavian artery as last branch of left-sided aortic arch or proximal descending aorta - Normally RSA originates from brachiocephalic artery

IMAGING

• General Features

  • Best diagnostic clue

    - ARSA as last branch of left-sided aortic arch or proximal descending aorta
    - Retroesophageal/retrotracheal course of ARSA
    

  • Location

    - ARSA takeoff from distal aortic arch, isthmus, or proximal descending aorta
    - Course: Retroesophageal 80%; intertracheoesophageal 15%; pretracheal 5%
    

  • Size

    - Usually normal vessel caliber
    - Dilated proximal segment in Kommerell diverticulum
    - Aneurysm may be present
    

  • Morphology

    - No vascular ring formed by left aortic arch and ARSA
            - Trachea and esophagus are in middle between aortic arch and ARSA
    - Loose vascular ring if ARSA originates from Kommerell diverticulum
            - Right ductus/ligamentum arteriosum completes ring 
                      - Ductus arising from junction between diverticulum and normal-sized subclavian artery
            - Seen in 15-30% of ARSA
    - Complete vascular ring if ARSA with circumflex right descending thoracic aorta and right ductus
            - Arch itself crosses midline, posterior to esophagus
            - Right ductus extends from descending aorta to right pulmonary artery, completing vascular ring
    

• Radiographic Findings

  • Chest x-ray may show enlargement of superior mediastinum
  • Barium esophagogram shows persistent esophageal narrowing at level of extrinsic compression with oblique course

• CT Findings

  • CTA

    - Excellent modality to demonstrate aortic arch configuration and branching pattern
    - MPR, MIP, and VRT reconstructions help to understand origin and course of supraaortic trunks
    - Evaluates esophageal and tracheal compression
    

  • NECT: May be seen incidentally

  • 4D CT: May show dynamic esophageal compression during cardiac cycle due to distension of ARSA during systole

• MR Findings

  • MRA

    - Arch vessel branching pattern is (from right to left): Right common carotid artery; left common carotid artery; left subclavian artery; right subclavian artery (RSA)
    - Course: Obliquely from caudal left to cranial right
    - Aneurysm of ARSA: 1.5x d of distal subclavian artery
    - Left ductus may be seen; no vascular ring
            - Since there is vasculature on only 3 sides of trachea and esophagus
    - Posterior esophageal compression in 10%
            - Usually in 4th or 5th decade
            - Stretching, sclerosis/calcification, aneurysm of ARSA
    - Complete vascular ring may be seen if
            - Kommerell diverticulum: Dilation of origin of ARSA
                      - Diameter of orifice of diverticulum and distance from furthest aortic wall to end of diverticulum measured
            - Circumflex right descending thoracic aorta with arch behind esophagus
    

  • SSFP cine

    - May show dynamic esophageal compression during cardiac cycle due to vessel distension during systole
    

• Imaging Recommendations

  • Best imaging tool

    - CTA or MRA
    

  • Protocol advice

    - ECG gating is not necessary if only evaluation of vascular ring is desired
            - High-pitch helical mode of dual source CT scanner (Flash) mode, provide anatomic information
    

DIFFERENTIAL DIAGNOSIS

• Major Aortopulmonary Collateral Arteries

  • Collateral vessels arising from descending aorta that end in lungs in patients with pulmonary artery atresia

• Right Arch With Aberrant Left Subclavian Artery

  • Mirror image of left arch with ARSA
  • Caused by persistent right 4th arch and regression of left 4th arch in between left common carotid and left subclavian arteries
  • Aberrant left subclavian artery originates as last branch from right aortic arch and courses behind esophagus to reach left
  • 90% have left ductus vascular ring - 2nd most common cause of complete vascular ring

• Retroesophageal Diverticulum

  • Outpouching at origin of aberrant left subclavian artery in right aortic arch; seen in 60% of these cases

PATHOLOGY

• General Features

  • Etiology

    - Embryologic insult during formation of aortic arches
    - Right 4th arch regresses between RSA and right common carotid artery, including ductus arteriosus
            - Distal right dorsal aorta forms proximal RSA
            - Distal portion from 7th right intersegmental artery
    - Kommerell diverticulum: Remnant of dorsal aortic arch
            - Persistence of right 6th arch component that forms right ductus arteriosus
    - Left circumflex aorta
            - Regression of right 4th arch between right common carotid and right subclavian arteries
            - Persistence of right 6th arch component that forms ductus
            - Right-sided descending aorta
            - Distal left dorsal aorta forms definitive distal aortic arch
    

  • Associated abnormalities

    - ARSA is present in 35% of patients with Down syndrome
    - Kommerell diverticulum: 14.9%
    - Aneurysm of distal RSCA: 12.8%
    - Others: Coarctation; patent ductus arteriosus; ventricular septal defect; truncus bicaroticus; type B interrupted arch
    

• Staging, Grading, & Classification

  • Retroesophageal course: 80%
  • Interesophageotracheal course: 15%
  • Pretracheal course: 5%

CLINICAL ISSUES

• Presentation

  • Most common signs/symptoms

    - 90-95% asymptomatic; usually incidental finding in imaging studies
    

  • Other signs/symptoms

    - Adults: Dysphagia (lusoria), dyspnea, back pain, arm claudication, abnormal chest x-ray
    - Infants: Cough, stridor, occasionally aspiration pneumonia
    - Rare: Ruptured diverticulum; dissection
    

• Demographics

  • Age: Any; mean at detection 41.8 ± 26.6 years
  • Sex: F:M = 3:1
  • Epidemiology - Most common congenital aortic arch abnormality - Prevalence 0.5-2.0% of population

• Natural History & Prognosis

  • Caution required during esophageal surgeries
  • Caution required in thyroid and parathyroid surgeries - Right inferior laryngeal nerve passes directly from vagus nerve at level of larynx to neck

• Treatment

  • Surgery for symptoms, aneurysm, or large diverticulum - Diverticulum orifice > 3-cm or > 5-cm depth between wall adjacent to trachea and opposite aortic wall

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References

Selected References

1. Robb CL et al: Subclavian artery: anatomic review and imaging evaluation of abnormalities. Radiographics. 42(7):2149-65, 2022
2. Mazzaccaro D et al: Analysis of origin of the supra-aortic trunks from the aortic arch. J Vasc Surg. 67(2):399-408, 2018
3. Hanneman K et al: Congenital variants and anomalies of the aortic arch. Radiographics. 37(1):32-51, 2017
4. Polednak AP: Prevalence of the aberrant right subclavian artery reported in a published systematic review of cadaveric studies: the impact of an outlier. Clin Anat. 30(8):1024-8, 2017
5. Allen D et al: Arteria lusoria: an anomalous finding during right transradial coronary intervention. Case Rep Cardiol. 2016:8079856, 2016
6. Tanaka A et al: Kommerell's diverticulum in the current era: a comprehensive review. Gen Thorac Cardiovasc Surg. 63(5):245-59, 2015
7. Etesami M et al: Computed tomography in the evaluation of vascular rings and slings. Insights Imaging. 5(4):507-21, 2014
8. Mahmodlou R et al: Aberrant right subclavian artery: a life-threatening anomaly that should be considered during esophagectomy. J Surg Tech Case Rep. 6(2):61-3, 2014
9. Roofthooft MT et al: Down syndrome and aberrant right subclavian artery. Eur J Pediatr. 167(9):1033-6, 2008
10. Donnelly LF et al: Aberrant subclavian arteries: cross-sectional imaging findings in infants and children referred for evaluation of extrinsic airway compression. AJR 178:1269-74, 2002

Images

Selected Images

CTA cinematic rendering reconstruction shows 5 branches from the aortic arch. From the proximal to distal, the branches are: Right common carotid artery , left internal carotid artery , left external carotid artery , left subclavian artery , and aberrant right subclavian artery (ARSA) . Mild aortic coarctation is also noted.

CTA cinematic rendering reconstruction shows 5 branches from the aortic arch. From the proximal to distal, the branches are: Right common carotid artery , left internal carotid artery , left external carotid artery , left subclavian artery , and aberrant right subclavian artery (ARSA) . Mild aortic coarctation is also noted.

CTA cinematic rendering reconstruction shows ARSA that originates as the last branch from the aortic arch and courses behind the esophagus to reach the right.

Coronal oblique MIP CTA shows a prominent Kommerell diverticulum , which is a dilatation of a proximal ARSA that originates in the proximal descending aorta .

Axial oblique MIP reconstruction from a CTA shows an ARSA with retroesophageal course causing esophageal compression between aortic arch, trachea , and ARSA.

Additional Images

Axial oblique MIP reconstruction from a CTA shows an ARSA that causes esophageal compression .

3D reconstruction of the airways and lungs from a CT in the same patient shows severe esophageal luminal narrowing from an ARSA.

MRA 3D posterior oblique view shows 6 branches from the aortic arch. From proximal to distal the branches are: A common trunk dividing into right common carotid artery and right vertebral artery , left internal carotid artery , left external carotid artery , left vertebral artery , left subclavian artery , and ARSA .

Sagittal T2-weighted MR of the cervical spine shows a round structure between the spine and esophagus , consistent with an aberrant right subclavian artery causing esophageal compression.

Coronal MIP reconstruction from a MRA shows an ARSA and a normal left subclavian artery , both originating at the same level in the distal aortic arch .

CTA cinematic rendering reconstruction shows a right-sided aortic arch with mirror-image branching and aberrant left subclavian artery , which originates as the last branch from the arch.

Coronal MIP CTA reconstruction in a 56-year-old man shows an ARSA originating from the proximal descending thoracic aorta and extending towards the right.

Axial MIP CTA reconstruction in a 56-year-old man shows an ARSA originating from the proximal descending thoracic aorta and extending towards the right, with compression of the esophagus .