Transposition of anomalous left vertebral to carotid artery during the management of thoracic aortic dissections and aneurysms

Objectives: Preservation of antegrade flow to the left vertebral artery (LVA) is often achieved by transposition or bypass to the left subclavian artery during zone 2 thoracic endovascular aortic repair. An anomalous LVA (aLVA) originating directly from the aortic arch is a common arch variant with a reported incidence of 4% to 6%. In addition, 6% to 10% of vertebral arteries terminate in a posterior inferior cerebellar artery, increasing the risk of stroke if not revascularized. Few series of aLVA to carotid transposition have been reported. The aim of this study was to evaluate the outcomes of patients who underwent aLVA to carotid transposition for the management of aortic disease. Methods: A retrospective review of all aLVA-carotid transpositions performed for the management of thoracic aortic dissection or aneurysm at a single center from 2018 to 2021 was performed. The primary outcomes were postoperative stroke and patency of the transposed aLVA. Secondary outcomes were spinal cord ischemia, postoperative cranial nerve injury, and Horner's syndrome. Results: Seventeen patients underwent aLVA to carotid transposition as an adjunct to management of aortic disease during the study period. Most were men (n = 14) and the mean age was 54 +/- 16 years. The primary indication for aortic repair was dissection in 10, aneurysm in 6, and Kommerell diverticulum in 1. Nine patients underwent zone 2 thoracic endovascular aortic repair, seven received open total arch repair, and there was one attempted total endovascular arch repair that was aborted owing to unfavorable anatomy. Twelve transpositions were performed before or concomitant with planned aortic repair owing to high-risk cerebrovascular anatomy (three posterior inferior cerebellar artery termination, six dominant aLVA, four intracranial LVA stenosis), and two were performed postoperatively for treatment of type II endoleak. LVA diameter ranged from 2 to 6 mm (mean, 3.3 mm). The mean operative time for transposition was 178 +/- 38 minutes, inclusive of left subclavian artery revascularization, and the mean estimated blood loss was 169 +/- 188 mL. No patients experienced 30-day postoperative spinal cord ischemia, stroke, or mortality. There were two cases of postoperative hoarseness, presumably owing to recurrent laryngeal nerve palsy, both of which resolved within 4 months. There were no cases of Horner's syndrome. At follow-up (mean, 306 days; range, 6-714 days), all transpositions were patent. Conclusions: Vertebral-carotid transposition is a safe and effective adjunct in the management of aortic disease with anomalous origin of the LVA.