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Anomalous origin of right vertebral artery from aortic arch distal to origin of left subclavian artery in a patient with aneurysm of aortic arch and type B dissection of aorta
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  1. Debanjan Nandi,
  2. Manish Shaw,
  3. Avichala Taxak and
  4. Sanjeev Kumar
  1. Cardiovascular Radiology & Endovascular Interventions, All India Institute of Medical Sciences, New Delhi, India
  1. Correspondence to Dr Sanjeev Kumar; sanjeevradio{at}gmail.com

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Description

A 67-year-old man, chronic smoker and alcoholic, hypertensive for 6 years on antihypertensive medication with no family history of Marfan’s syndrome or any other genetic arteriopathy, presented with backache for 4 months and shortness of breath (New York Heart Assosciationgrade II) for 2 months not associated with vomiting, syncope, haemoptysis, angina and palpitation. No history of fever or altered sensorium was seen. His heart rate was 76/min, respiratory rate was 18/min and four-limb blood pressure was normal. Oxygen saturation was 98% on room air. Multidetector CT angiography for coronary artery and aorta was done using a third generation dual-source scanner. The aortic valve was tricuspid with normal coronary arteries. Ascending aorta was dilated (maximum diameter 44.2 mm) and descending thoracic aorta was significantly tortuous (figure 1). A large fusiform aneurysm (figures 1 and 2) was arising from distal aortic arch and proximal descending thoracic aorta with eccentric peripheral thrombosis wall calcifications. The maximum (total) diameter of aneurysm in proximal descending thoracic aorta was 12.5 cm and maximum diameter of true lumen was 5.0 cm. Dissection flap (figure 3) was extending from juxta-diaphgramatic descending thoracic aorta to abdominal aorta, left common iliac artery and ostioproximal external iliac artery and internal iliac artery. Coeliac axis and superior mesenteric artery were arising from true lumen with no significant disease. The vertebral artery was co-dominant. The right vertebral artery (figures 1, 2 and 4) was arising directly from the aneurysmally dilated arch segment after origin of left subclavian artery (figure 2) with retro-oesophageal course. The left vertebral artery (figures 2 and 4) was arising from the left subclavian artery.

Figure 1

(A) Axial CT maximum intensity projection image shows origin of right vertebral artery (shown by black arrow) directly from arch aneurysm with large eccentric thrombus/haematoma. (B) Sagittal CT maximum intensity projection image shows large aneurysm involving arch and descending thoracic aorta (shown by double-ended arrow) with origin of right vertebral artery from the proximal aspect of aneurysm segment.

Figure 2

(A) Cinematic volume-rendered CT image shows origin of right vertebral artery (shown by black arrow) from arch after origin of left subclavian artery (shown by white thin arrow); right vertebral artery (shown by white thick arrow) arises from proximal right subclavian artery. (B) Cinematic volume-rendered image shows origin of right vertebral artery (shown by black arrow) from arch; right vertebral artery (shown by white thick arrow) arises from proximal right subclavian artery.

Figure 3

(A) Cinematic volume-rendered CT coronal image (from anterior aspect) shows extent of dissection flap into descending thoracic aorta, abdominal aorta and left common iliac artery. (B) Cinematic volume-rendered CT coronal image (from posterior aspect) shows extent of dissection flap into descending thoracic aorta, abdominal aorta and left common iliac artery.

Figure 4

(A) Curved sagittal reformatted CT image showing entire course of right vertebral artery (shown by black arrow). (B) Curved sagittal reformatted CT image showing entire course of left vertebral artery (shown by white arrow). (C) Coronal maximum intensity projection CT image showing confluence of right vertebral artery (shown by black arrow) and left vertebral artery (shown by white arrow) forming basilar artery (shown by white arrowhead).

Anomalous origin of the vertebral artery is rarely encountered and mostly seen (2.4%–5.8%) in the left vertebral artery, which originates directly from aortic arch between left common carotid artery and left subclavian artery.1 Anomalous origin of right vertebral artery is a rarer entity. This is classified into three categories: those originating from the aorta, those originating from the carotid arteries or brachiocephalic artery, and those of duplicated origin.2 To date, only 23 cases of right vertebral artery originating from aortic arch distal to the origin of left subclavian artery have been reported in literature.3 None of the cases were associated with descending thoracic aorta aneurysm and type B aortic dissection. As per embryology, an aberrant right vertebral artery originating from the arch distal to the left subclavian artery implies a persistence of the proximal dorsal aorta on the right side with segmental regression of the dorsal aorta between the sixth and seventh intersegmental arteries.4 The importance of finding the anomalous origin of right vertebral artery in our case was that, in case of endovascular management, both the vertebral arteries would be occluded after deployment of aortic stent graft, thereby causing posterior intracranial circulation impairment. In such cases, surgery would be preferable instead of endovascular management.

Learning points

  • Direct origin of right vertebral artery from aortic arch is rarer compared with direct origin of left vertebral artery.

  • None of the reported cases of direct origin of right vertebral artery from arch are associated with aneurysm and dissection.

  • In case of endovascular management in case of aortic dissection with anomalous right vertebral artery origin directly from arch, occlusion of both the vertebral arteries by aortic stent graft will cause posterior intracranial circulation impairment. In such cases, surgery would be preferable instead of endovascular management.

  • CT imaging of both carotid and vertebral arteries including the circle of Willis, prior to planning of aortic arch surgery, such as carotid-subclavian bypass or endovascular aortic intervention, is necessary.

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References

Footnotes

  • Contributors DN—planning, acquisition and interpretation of data, writing the manuscript, patient care. MS—conceptualising and editing the manuscript. AT—writing the manuscript. SK—analysis and interpretation of data, final approval of the version. DN submitted the article. DN ensured all authors give permission to be included. SK is the corresponding author, who accepts full responsibility for the finished work and/or the conduct of the study, had access to the data and controlled the decision to publish.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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