Use of overlapping Surpass Evolve Flow Diverters for the treatment of a ruptured P1 dissecting aneurysm in the context of bilateral carotid artery occlusion: A case report.

In the setting of internal carotid artery (ICA) occlusion, a dissecting aneurysm may develop and rupture in the P1 segment of the posterior cerebral artery. While endovascular treatment (EVT) represents a viable treatment option, optimal technique selection remains controversial. This report describes a rare case of a ruptured P1 dissecting aneurysm associated with bilateral ICA occlusion, which was successfully treated using overlapping Surpass Evolve Flow Diverters (SE FDs). A 61-year-old Han Chinese woman presented with subarachnoid hemorrhage (Hunt-Hess grade II). Digital subtraction angiography demonstrated bilateral ICA occlusion and a ruptured P1 dissecting aneurysm with a thickened P1 segment. After a loading dose of aspirin and ticagrelor, EVT was performed. After an unsuccessful attempt at coil embolization assisted by a SE FD, 2 overlapping SE FDs, measuring 4.5 mm × 17 mm and 4.5 mm × 15 mm, were deployed to cover the P1 dissecting aneurysm. Postoperatively, the patient demonstrated no new neurologic deficits. However, on postoperative day 11, she developed left upper limb weakness of Grade III muscle strength due to vasospasm. Management with intravenous hydration and nimodipine infusion resulted in marked improvement. Two-month follow-up computed tomography angiography confirmed occlusion of the P1 dissecting aneurysm. The patient's left limb muscle strength recovered to Grade IV. At 6 months' follow-up, she was almost normal. It is hypothesized that, in this case of bilateral ICA occlusion, hemodynamic stress may have contributed to the formation of the ruptured P1 dissecting aneurysm. Overlapping SE FD deployment proved to be a feasible treatment option.