Thrombectomy REvascularization of Large Vessel Occlusions in Acute Ischemic Stroke (TREVO)

Inclusion Criteria: * Age 18-79 (has had 18th birthday, but not yet had 80th birthday) * NIHSS 8 - 30 * Anticipated life expectancy of at least 6 months * No significant pre-stroke disability (mRS less than or equal to 1) * Written informed consent to participate given by patient or legal representative * Angiographic confirmation of a persistent large vessel occlusion, in the internal carotid, middle cerebral M1 and/or M2 segments, basilar or vertebral arteries * Treatable within 8 hours of symptom onset, defined as the first pass being made with the Trevo device. Exclusion Criteria: * Baseline glucose of \< 50 mg/dL (2.78 mmol) or \> 400 mg / dL (22.20 mmol) * Known hemorrhagic diathesis, coagulation factor deficiency, or oral anticoagulant therapy with INR \> 3.0 * Treated with Heparin within 48 hours with a PTT greater than 2 times the lab normal * Baseline platelet count \< 30,000 * History of severe allergy (more than rash) to contrast medium * Severe, sustained hypertension (SBP \> 185 mm Hg or DBP \> 110 mm Hg) NOTE: If the blood pressure can be successfully reduced and maintained at the acceptable level using medication (i.e. Nipride), the patient can be enrolled * Woman of child bearing potential who is known to be pregnant * Patient participating in another clinical study or protocol * For anterior circulation strokes: strokes involving greater than 1/3 of the MCA territory, as determined by hypodensity on the baseline non- contrast CT, or low CBV on CT Perfusion imaging, or restricted diffusion on DWI images * For posterior circulation strokes within the midbrain and/or pons, extensive hypodensity on the baseline CT, or low CBV on CT Perfusion imaging, or extensive restricted diffusion on DWI images * Baseline CT/MR evidence of significant mass effect with midline shift * Baseline CT/MR evidence of hemorrhage * Baseline CT/MR evidence of intracranial tumor (except small meningioma) * Angiographic evidence of vasculitis or arterial dissection * High grade stenosis that cannot be treated safely or which prevents access to the thrombus with the Trevo device * Angiographic evidence of excessive arterial tortuosity that precludes the Trevo device from reaching the thrombus