Presentation
Preoperative evaluation for CABG. Patient had episode of a stroke 2 months prior.
Patient Data



CT angiography shows a tight stenosis in the right subclavian artery proximal to origin of vertebral artery. The origin of left vertebral artery and its proximal segment is occluded and shows no IV contrast fill. The distal left vertebral artery is supplied by collateral vessels arising from left subclavian artery.
Case Discussion
A high grade stenosis of the right subclavian artery was seen on CT angiography. There is also a complete occlusion of left vertebral artery artery from its origin to the V1 segment. The V2 segment is supplied by collaterals arising from left subclavian artery.