Introduction/Purpose Flow-diverting stents (FDS) are effective in treating complex intracranial aneurysms including posterior communicating artery (PCoA) aneurysms. However, some studies have suggested a decrease in efficacy of FDS in treating PCoA aneurysms associated with a fetal PCoA (FPCoA), postulating that the increased flow through the FPCoA prevents endothelialization of the FDS required for aneurysm occlusion. Others have expressed concern that treating FPCoA aneurysms using FDS could result in posterior circulation ischemia from reducing blood flow through the FPCoA. We therefore reviewed our institutional experience using FDS as a stand-alone intervention to treat complex FPCoA aneurysms.

Material/Methods We performed a retrospective analysis of our endovascular database from 1/2012 to 12/2018 to identify patients with FPCoA aneurysms treated using a FDS as the standalone intervention. We identified aneurysms where the FPCoA vessel originated from the neck or dome of the aneurysm and who were therefore not appropriate candidates for standard coil embolization. We extracted demographic, clinical, treatment, and radiographic data. We considered a FPCoA as any PCoA with a caliber larger than the visualized P1 segment of the posterior cerebral artery.

Results We performed stand-alone, single-device, FDS treatments for 16 PCoA aneurysms associated with FPCoA vessels that originated from either the neck or dome of the aneurysm. Ten of these 16 aneurysms were previously treated (6 coiled, 3 clipped, and 2 multiple open/endovascular interventions) and the FDS was used to treat a recurrence/residual. Seven were previously ruptured. For all cases, we carefully sized the device to ensure excellent wall apposition and focused on device expansion into the neck of the aneurysm to optimize flow-diversion. Using this technique, we achieved an excellent angiographic result in 12 of the 16 cases (75%), with complete obliteration of the aneurysm in 10 cases (62.5%) and near complete obliteration with only trace filling of a neochannel at the aneurysm base in 2 (12.5%). In the remaining 4 (25%) cases, in whom follow-up is ongoing, we observed significant, progressive aneurysm occlusion with marked flow stagnation within the remaining aneurysm. No cases have necessitated additional treatment. We assessed FPCoA patency on follow-up angiography in all patients and observed complete patency in 9, present but decreased flow in 4, markedly diminished flow in 2, and FPCoA occlusion in 1 patient. In all 7 cases with decreased FPCoA flow, we noted co-incident increased P1 flow. No patient exhibited symptoms attributable to posterior circulation ischemia. No procedural complications were encountered and all patients remained neurologically stable following treatment. Mean clinical and angiographic follow-up was 19.9 months.

Conclusion FDS can be a safe and effective treatment option for PCoA aneurysms despite the presence of a FPCoA and can result in satisfactory occlusion rates without posterior circulation ischemia. The deployment technique of maximizing device expansion across the neck of the aneurysm may contribute to successful outcomes. Treatment using a FDS may be of particular utility for complex FPCoA aneurysms where – because of their morphology, relation to the FPCoA vessel, or prior treatments attempted –the ability for standard coiling or microsurgical treatment is limited.

Disclosures J. Baranoski: None. S. Merrill: None. B. Hendricks: None. J. Catapano: None. T. Cole: None. N. Majmundar: None. D. Wilkinson: None. F. Albuquerque: None. A. Ducruet: None.