Introduction: The initial experience with the Penumbra Coil 400 (PC400) system has been positive regarding safety, efficacy, improved packing density, and cost effectiveness but follow-up data is limited.

Methods: Seventy-six aneurysms treated with PC400 coils were compared to 301 aneurysms treated with a variety of different bare platinum and bioactively coated coils. In addition to procedural data, immediate and first follow-up occlusion class was compared.

Results: Compared to controls, the PC400 group had fewer coils used (3.53 vs. 5.44, p=0.00190), decreased procedure time (48 min. vs. 64 min., p=0.00016), and increased packing density (31.70% vs. 24.83%, p<0.00001). Compared to controls, there were more grade III (71.05% vs 38.21%, p<0.00001) and fewer grade I aneurysms (13.16% vs 30.23%, p=0.00220) in the PC400 group immediately following the procedure. At first follow-up, however, more aneurysms in the PC400 group improved (51.28% vs 28.71%, p=0.0085) in angiographic grade and fewer worsened (5.13% vs 11.39%, p=0.3882). Both groups had similar rates of acceptable outcome (grade 1 or 2) at first follow-up (PC400 79.49% vs. Control 77.22%). There were fewer retreatments in the PC400 group that approached statistical significance (2.63% vs. 9.30%, p=0.0585).

Conclusions: Compared to control coils, PC400 coils achieve higher packing density with fewer coils and decreased procedure time. Furthermore, although there was a larger number of grade III aneurysms in the PC400 group immediately after the procedure, there was a greater tendency for these aneurysms to improve in angiographic grade at first follow-up leading to similar rates of acceptable outcome.

Patient Care: The goal of this research is to better understand the efficacy of the PC400 system in the treatment of cerebral aneurysms on both a short and long term scale. Interventional neurosurgeons will hopefully be able to use these results to make more informed decisions when choosing coil types during aneurysm embolization.

Learning Objectives: By the conclusion of this session, participants should be able to: 1) Understand how PC400 coils compare to control coils during initial treatment; 2) Understand how PC400 coils compare to control coils at 6 month follow-up specifically regarding aneurysm occlusion class

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