Figure 2. Intervention.(a) Lateral left vertebral artery (VA) angiography after the implantation of one coronary stent reveals a partial contrast stasis in the aneurysmal sac in the venous phase. (b) Lateral left VA angiography after three coronary stents implanted with a "stent-within-a-stent" technique reveals further stasis in the aneurysmal sac in the venous phase. Stents are barely visible due to their poor radiopacity. (c) Right VA test injection before the positioning of the guiding catheter reveals an unusually winding course at C5 level. (d) Right VA test injection immediately after the positioning of the 6 F guiding catheter at the origin of the right VA reveals complete occlusion at the C5 level. (e) Fluorography of the neck 30 min after the right VA occlusion reveals contrast stasis without any movement, although a bolus of verapamil was administered and the guiding catheter had been withdrawn. (f) Left VA angiography after the right VA occlusion reveals the retrograde filling of the right PICA and infra-PICA dissecting aneurysm.