O-014 Long-term durability of simple and balloon-assisted coil embolization for treatment of intracranial aneurysms

Purpose To determine recanalization and post-treatment rupture rates in a large cohort of patients with intracranial aneurysms treated with simple or balloon-assisted coil embolization. Methods We retrospectively reviewed consecutive patients with intracranial aneurysms treated with simple or balloon-assisted coil embolization at our institution from August 8th, 1995 to September 30th, 2017. Baseline aneurysm and patient characteristics, procedural variables and angiographic outcomes were recorded. Aneurysm recanalization was defined as Raymond 3 or Raymond 2 with a neck remnant ≥4 mm or ≥33% of initial aneurysm volume. Multivariate regression analysis was performed to identify independent variables associated with aneurysm recanalization. Results 1634 patients with 1935 intracranial aneurysms were included, 1196 women (73%), mean age 56 years (median 56 years, 8–97 years). 1125 aneurysms were incidental (58.1%), 752 ruptured (38.9%) and 58 symptomatic (3%). Mean aneurysm size 6.3 mm (median 5.5 mm, 1.6–27.9 mm), mean neck 3 mm (median 2.8 mm, 0.6–16.2 mm), mean dome-to-neck ratio 1.7 (median 1.5, 0.7–6.5). Aneurysm locations: 502 ICA (25.9%), 461 Acomm (23.8%), 375 MCA (19.4%), 276 Pcomm (14.3%), 128 basilar tip (6.6%), 79 other ACA (4.1%) and 114 other posterior circulation (5.9%). 749 aneurysms were treated with simple coiling (38.7%) and 1186 with balloon-assisted coiling (61.3%), mean packing density 33.4% (median 31.5%, 6.5%–94.9%). Angiographic follow-up was completed in 1574 of 1730 aneurysms available (91%), mean time to last follow-up 5.3 years (median 4.4 years, 0–20.5 years). Aneurysm occlusion at last follow-up was Raymond 1 in 878 aneurysms (55.8%), Raymond 2 in 496 aneurysms (31.5%), and Raymond 3 in 200 aneurysms (12.7%). There were 254 aneurysm recanalizations at last follow-up (16.1%), and 202 aneurysms were retreated (12.8%). Table 1 summarizes independent predictors of aneurysm recanalization in our cohort. Table 2 summarizes recanalization rates by location and rupture status. 13 aneurysms ruptured after coiling (0.8%), corresponding to an annual post-treatment rupture rate of 0.15%. Mean time from treatment to rupture was 5.8 years (median 4.5 years, 0–12.7 years). Mean time from last angiographic evaluation to rupture was 2.2 years (median 1 year, 0–10.2 years). Aneurysm occlusion at the last angiographic evaluation prior to rupture was Raymond 1 in 4 aneurysms, Raymond 2 in 3 aneurysms, and Raymond 3 in 6 aneurysms. 12 post-treatment ruptures occurred in aneurysms treated before 1/1/2008. Conclusion Endovascular aneurysm treatment with coils alone is associated with relatively high long-term recanalization and post-treatment rupture rates, especially after treatment of ruptured aneurysms. Long-term angiographic follow-up and early retreatment of recanalized aneurysms would be prudent. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Microvention/Terumo, Penumbra, Inc. Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra, Inc. A. Wallace: None. J. Fease: None. J. Scholz: None. A. Milner: None. M. Mulder: None.