Transposition of left subclavian artery with reimplantation of isolated left vertebral artery before thoracic endovascular aneurysm repair for type B aortic dissection.

Understanding and recognizing anatomic anomalies of the aortic arch is important when planning extra-anatomic debranching before thoracic endovascular aortic repair. A rare anomaly is the left vertebral artery aberrantly arising from the aortic arch; found in ∼5% of adults. When present, the artery courses through the carotid sheath at a variable length before entering the third or fourth cervical transverse foramen.