Objective:

With this report we are highlighting rare anatomic variation that can hide the etiology of recurrent stroke and treatment method we deployed.

Background:

The duplicated origin of the left vertebral artery(VA) is a rare anatomical variation, where the artery has two distinct origins. Typically one limb(lateral) originate from left subclavian artery and the other(medial) from the aortic arch. We present a case in which dissection of medial limb was the etiology of multiple posterior circulation ischemic strokes. 

Design/Methods:

Retrospective review and description of clinical case. Literature review on topic of this anatomical variation.

Results:

We present a case of 61 year-old male who had 3 previous posterior circulation strokes, including two basilar thrombectomies. Both thrombectomies were performed via left VA access from left subclavian artery. He was noticed to have transition of diameter in distal V2 segment left VA without dissection flap or flow limitation. Right VA was hypoplastic. Extensive work up had failed to reveal any other underlying etiology. He was on mono antiplatelet treatment after first stroke (14 months prior), dual antiplatelet treatment (2 months prior) and apixaban with dual antiplatelet treatment after third stroke (one month prior). During follow-up elective diagnostic catheter angiogram, aortic arch run revealed tapered stump of medial limb of duplicated left VA. Left VA lateral limb injection revealed partial recanalization of distal end of medial limb where it anastomoses with lateral limb in distal V2 segment. Medial limb is thought to be dissection occluded and likely source of recurrent emboli. It was treated with flow diverter stent extending from distal end of lateral limb into distal V2 segment of left VA, covering anastomotic point with diseased medial end. 

Conclusions:

This rare anatomic variation can be harbinger of stroke etiology and requires extra attention to all modalities of vessel imaging.