This is a prospective, randomized, single blind, concurrent controlled, multi-center study.
Patients presenting with symptoms of acute ischemic stroke who have evidence of a large
vessel (2.5mm or greater in diameter) occlusion in the cerebral circulation will be assigned
to either the Penumbra System with the Separator 3D or the Penumbra System without the
Separator 3D. Each treated patient will be followed and assessed for 3 months after
randomization. Up to 230 evaluable patients at up to 50 centers presenting with acute
ischemic stroke in vessels accessible to the Penumbra Separator 3D System for
revascularization within 8 hours of symptom onset. The hypothesis to be tested is that the
safety and effectiveness of the Penumbra System with the Separator 3D for the
revascularization of large vessel occlusion is not inferior to the Penumbra System alone.