ReStore Thrombectomy Trial for Flow Restoration in Acute Ischemic Stroke Patients

Inclusion Criteria: * Age ≥ 22 and ≤ 85 years * Clinical signs consistent with the diagnosis of acute ischemic stroke * Pre-stroke Modified Rankin Score ≤2 * National Institute of Health Stroke Scale (NIHSS) assessment score ≥8 and \<30 * Patient presents between 0 and 8 hours of onset of stroke symptoms * Contraindicated for IV t-PA treatment (as specified by drug manufacturer's IFU) OR Acute ischemic stroke treated with intravenous thrombolytic therapy where vascular imaging (TCD, CTA, MRA, or angiography) shows a persistent occlusion after the end of the infusion treatment. NOTE: * Treatment initiated within 8 hours after symptom onset (first retrieval pass made within 8 hours) * Neurologic signs that are NOT rapidly improving (NIHSS score has NOT decreased by 4 or more points as determined prior to or at the time of treatment as compared to the initial screen; * TIMI 0 or 1 flow in internal carotid, middle cerebral M1/M2 segments, basilar, or vertebral arteries confirmed by angiography which are accessible to the retrieval devices. * Patient/patient legal authorized representative willing to comply with protocol requirements and return to the treatment center for all required clinical evaluations * Patient or legally authorized representative has given informed consent, and consent is documented. Exclusion Criteria: * NIHSS ≥30 or comatose * Known to be pregnant * Serum glucose level \<50 mg/dL * Excessive cervical arterial tortuousity that prevents placement of the retrieval devices * Known hemorrhagic diathesis * Patients exhibiting signs suggestive of or angiographic evidence of bilateral stroke * Coagulation factor deficiency (or oral anticoagulation therapy with INR\>3.0) * In receipt of heparin within 48 hours with a PTT \> 2x the lab normal * Baseline platelets \<30,000 mm3 * Known serious sensitivity to intra-arterial radiographic contrast agents * Severe sustained hypertension (systolic blood pressure \> 185 mmHg or diastolic \>110 mmHg) * Baseline CT or MRI revealed significant mass effect with midline shift or greater than 1/3 of the MCA region with hypodensity (sulcal effacement and/or loss of gray-white differentiation is allowed) * Neurologic signs that are rapidly improving at the time of treatment as measured by a decrease in NIHSS score of 4 or more points as determined prior to or at the time of treatment as compared to the initial screen * CT or MRI evidence of hemorrhage on presentation * CT or MRI evidence of mass effect or intracranial tumor (except small meningioma) * Life expectancy \< 3 months * Angiographic evidence of carotid dissection, or high grade stenosis (\> 50% stenosis of the artery proximal to the target vessel) that will prevent access to the clot, or vasculitis * At the discretion of the investigator, patients with co-morbidities associated with a life expectancy of less than 3 months or co-morbidities that could influence the study results or make clinical follow-up difficult will be excluded.