Early Aneurysm Occlusion Outcomes After Endovascular Treatment: A Descriptive Single-Center Cohort Evaluation

Early residual or recurrent aneurysm filling remains an important limitation after endovascular treatment of intracranial aneurysms, particularly in large and complex lesions. This study descriptively evaluated 6-month early residual or recurrent filling after coil embolization, stent-assisted coiling, flow-diverting stents, and the Woven EndoBridge (WEB) device in a single-center cohort.

We retrospectively analyzed 151 patients with 161 intracranial aneurysms treated between January 2019 and July 2023. Follow-up imaging at approximately 6 months was performed using computed tomography angiography or magnetic resonance angiography, with digital subtraction angiography when residual filling was suspected. Aneurysm occlusion was evaluated using the Raymond-Roy Occlusion Classification. Clinical, morphological, anatomical, and treatment-related variables associated with early residual or recurrent aneurysm filling were analyzed.

Complete occlusion was achieved in 149 aneurysms (92.5%), whereas early residual or recurrent filling occurred in 12 aneurysms (7.5%). Residual or recurrent filling was observed in 4/35 aneurysms treated with coil embolization (11.4%), 1/58 treated with flow-diverting stents (1.7%), 7/60 treated with the WEB device (11.7%), and none of the 8 aneurysms treated with stent-assisted coiling; overall rates did not differ significantly among treatment modalities (p = 0.104). Aneurysm height > 10 mm was significantly associated with early residual or recurrent filling (p = 0.005), and mean aneurysm height was greater in aneurysms with residual or recurrent filling than in completely occluded aneurysms (p = 0.048). In the ICA subgroup, residual or recurrent filling was more frequent after WEB treatment than after other endovascular modalities (p = 0.019). This subgroup signal was based on sparse observations.

Aneurysm height > 10 mm was significantly associated with early residual or recurrent aneurysm filling. No statistically significant difference in early residual or recurrent filling was detected among treatment groups. Given the retrospective design, non-random treatment allocation, heterogeneous aneurysm phenotypes, and non-uniform imaging follow-up, these data should be interpreted as a descriptive institutional experience rather than evidence of comparative superiority or equivalence. The ICA subgroup finding is preliminary and hypothesis-generating.