Patient description: A 62-year-old African-American man presented with left upper and lower extremity weakness, associated with dark visual spot in right eye, right facial numbness, facial drop and slurred speech. He denied dyspnea, headache, palpitations, chest pain, fever, dizziness, bowel or urinary incontinence, loss of consciousness. His medical history was significant for hypertension, hyperlipidemia and hypothyroidism. He smokes cigarette 1 pack per day for 40 years and alcohol consumption of 5 to 6 beers per week. He is not aware about his family history. He is using Levothyroxine, Atorvastatin and HTCZ. His vital signs were stable in the primary evaluation. Left-sided facial droop, dysarthria, and left-sided hemiplegia were seen in the physical exam. His National Institutes of Health Stroke Scale (NIHSS) score was calculated as 7. Initial CT angiogram of head and neck reported no acute intracranial findings. Intravenous recombinant tissue plasminogen activator (t-PA) was administered as well as high-dose statin therapy. The patient was admitted to the intensive care unit to be monitored for 24 hours. MRI of the head revealed an acute 1.7-cm infarct of the right periventricular white matter and posterior right basal ganglia.

Clinical trial eligibility criteria: eligible ages (years): 18.0-999.0,  Ischemic Stroke Acute Stroke Age 18 and older 2. NIHSS >=6 3. The operator feels that the stroke can be treated with endovascular thrombectomy approaches and the interventionalist estimates that groin puncture can be achieved within 24 hours from the onset of symptoms 4. Pre-event mRS score 0-1 5. Large vessel occlusion of the internal carotid artery (ICA) or middle cerebral artery (MCA)-M1 segments as evidenced by MRA or CTA 6. >=6 7. Less than 1/3 MCA territory involved, as evidenced by baseline CT or MRI 8. If stroke onset is within 6-24 hours, perfusion imaging is required to demonstrate a small core infarct volume (≤50cc for patients under 80 years old and ≤20cc for patients 80 years or older). 9. Non-contrast CT/CTA or MRI/MRA for trial performed or repeated at treating stroke center or outside medical facility within two hour of treatment initiation. 10. If indicated, IV t-PA should be administered as soon as possible, but no later than 3 hours from onset of stroke symptoms (onset time is defined as the last time when the patient was witnessed to be at baseline), with investigator verification that the subject has received or is receiving the correct IV t-PA dose for the estimated weight prior to randomization 11. Consenting requirements met according to local IRB or ethics committee  Female known to be pregnant at time of admission 2. Patient has suffered a stroke in the past 3 months 3. Presence of an existing or pre-existing large territory infarction 4. Pre-existing neurological or psychiatric disease that would confound the neurological or functional evaluation, e.g. dementia with prescribed anti-cholinesterase inhibitor. 5. Known history of severe contrast allergy or absolute contraindication to iodinated contrast or nickel. 6. Clinical history, past imaging or clinical judgement suggest that the intracranial occlusion is chronic 7. Life expectancy of less than 6 months prior to stroke onset 8. Clinical symptoms suggestive of bilateral stroke or stroke in multiple territories 9. Subject participating in another clinical trial involving an investigational device or drug 10. Known cancer with metastases 11. Evidence of active systemic infection 12. Any known hemorrhagic or coagulation deficiency Image Evidence of intracranial hemorrhage on CT/MRI 14. Core infarct lesion volume >50 cc 15. CTA or MRA evidence of extracranial carotid stenosis requiring treatment for intracranial access 16. Excessive vascular access tortuosity that will likely prevent endovascular access 17. Intracranial stent implanted in the same vascular territory that would preclude the safe deployment/removal of the thrombectomy devices. 18. Occlusions in multiple vascular territories (e.g., bilateral anterior circulation, or anterior circulation/vertebrobasilar system) as confirmed on CTA/MRA, or clinical evidence of bilateral strokes or strokes in multiple territories 19. Significant mass effect with midline shift as confirmed on CT/MRI 20. Evidence of intracranial tumor (except small meningioma defined as ≤ 3cm and asymptomatic) as confirmed on CT/MRI