Vertebral Artery Aneurysm: Stent-Assisted Coil Occlusion, Early Reperfusion, ASA/Metamizol Interaction with Poorly Controlled Platelet Function Inhibition, p64 Implantation, Aneurysm Reperfusion and Thrombus-Related Inflammation, Telescoping PED Implantation and Anti-Inflammatory Medication; Angiographic Exclusion of the Aneurysm, Regression of the Inflammation and Good Clinical Outcome

Abstract

A 58-year-old female patient was diagnosed with an incidental aneurysm of the left vertebral artery (VA) adjacent to the origin of the posterior inferior cerebellar artery (PICA). The wide-necked saccular aneurysm was partially thrombosed and exerted a minor space occupying effect on the brain stem. Stent-assisted coil occlusion was followed by a major recurrent perfusion of the aneurysm 6 months later. After a further 19 months, the reperfusion of the aneurysm had further increased. When the intended p64 flow diverter (FD) was implanted, the aneurysm was found to be almost entirely thrombosed. This was most likely related to the intake of metamizole, which undermines the ability of acetylsalicylic acid (ASA) to inhibit platelet function. Just 3 months after implanting the p64 flow diverter (FD), another significant reperfusion of the aneurysm was observed. In the meantime, the patient had continued occasional taking metamizole, but now mostly separate from ASA. In addition, a significant perianeurysmal inflammatory reaction and contrast enhancement of the aneurysm wall was observed. Almost 5 months after implanting the p64, a PED Flex FD was telescopically deployed into the left V4 segment. This second FD, alongside anti-inflammatory medication, led to the aneurysm being excluded from blood circulation. The thrombus-induced inflammation of the aneurysm wall and the adjacent brain stem ceased. The interaction of ASA and metamizole in the context of treating aneurysms by flow diversion is the main topic of this chapter.