Figure 2. a. Initial angiogram. There is wall irregularity (solid arrow) and possible pseudoaneurysm (dashed arrow) in the distal cervical segment of the left vertebral artery. There is no opacification of the intra-dural segment of the left vertebral artery distal to the posterior inferior cerebellar artery (open arrow) secondary to possible dissection with thrombus. b. Follow up angiogram after mechanical thrombectomy. There is opacification of the left vertebral artery (solid arrow) and the distal basilar artery (dashed arrow). There is reflux opacification of the right vertebral artery (open arrow). c. Follow up angiogram after heparin administration. There is opacification of the bilateral vertebral and basilar arteries (solid arrows). There is opacification of the right posterior cerebral artery (dashed arrow). There is opacification of the left posterior cerebral artery with contrast extravasation (open arrow). d. Final post-thrombectomy angiogram. There is opacification of the bilateral vertebral and basilar arteries (solid arrows). There is opacification of the right posterior cerebral artery (dashed arrow). The left posterior cerebral artery is poorly opacified (open arrow). The contrast extravasation seen previously (Figure 2c) has been successfully treated after heparin reversal with protamine. Of note, the left vertebral artery appears to be the dominant vertebral artery in this patient; the right vertebral artery is considerably smaller than the left.