E-106 Timeline of occlusion for intracranial aneurysms treated with pipeline embolization devices

Introduction/Purpose The Pipeline Embolization Device (PED) is commonly used to treat intracranial aneurysms. The rate of aneurysm occlusion at pre-specified timepoints after PED treatment is known from clinical trials, but the actual time evolution of aneurysm occlusion is not known. In this study, we take advantage of real-world variability in the timing of angiographic follow up to characterize the time evolution of aneurysm occlusion. Materials and Methods Data from a large, urban, tertiary care center was retrospectively analyzed. Only saccular, unruptured aneurysms treated with PED were included in this study. Aneurysm occlusion over time was characterized with Kaplan-Meier analysis. Aneurysms were censored after angiographic confirmation of complete aneurysm occlusion. Aneurysms were grouped by size (small <4 mm, medium 4-10 mm, large >10 mm) or number of PED’s deployed (1 vs >1). Kaplan-Meier curves were compared using a log-rank Mantel-Cox test. Time to occlusion as reported as median (95% CI). Results 291 aneurysms in 222 patients were included in this analysis. Large aneurysm size was significantly associated with a lower probability of complete occlusion at 5 years (figure 1A, p=0.037). Aneurysm size was not significantly associated with time to aneurysm occlusion. Median time to occlusion was similar across sizes: 7.7 months (CI 6.7-9.8) for small aneurysms, 6.9 months (CI 6.6-7.6) for medium aneurysms, and 8.0 months (CI 7.1 -17.7) for large aneurysms. When stratified by number of PEDs deployed, survival curves were not significantly different (figure 1B, p=0.479). Median time to occlusion was 7.2 months (CI 6.7-7.8) for aneurysms treated with 1 PED and 7.7 months (CI 6.9-11.8) for aneurysms treated with multiple PEDs. Conclusion Aneurysm size and number of PEDs did not significantly alter aneurysm behavior at early angiographic follow up. However, large aneurysms demonstrated an earlier plateau in their likelihood of complete occlusion. These findings are relevant for determining optimum angiographic follow up schedules and providing anticipatory guidance to patients. Disclosures S. Cler: None. D. Lauzier: None. A. Kansagra: 2; C; Penumbra, Microvention, iSchemaView.