First-pass Recanalization With EmboTrap II in Acute Ischemic Stroke (FREE-AIS)

Inclusion Criteria: 1. Subjects experiencing acute ischemic stroke due to large vessel occlusion (intracranial internal carotid artery and middle cerebral artery M1 or proximal M2 segment, intracranial vertebral artery and basilar artery 2. Age 19 or greater 3. mRS before qualifying stroke, 0 to 2 4. Baseline NIHSS score 4 or more 5. CT ASPECTS \> 5 or MR ASPECTS \> 4 6. Good collateral statues on CT angiogram (collateral grade by Calgary group, 4 or 5) or corresponding to DEFUSE 3 or DAWN trial on perfusion imaging. 7. Onset (last-seen-well) time to femoral puncture time \< 24 hours 8. Anticipated life expectancy of at least 12 months 9. Patients who undergo endovascular thrombectomy with EmboTrap II as the first-line device 10. Signed informed consent for study enrollment Exclusion Criteria: 1. Multiple simultaneous large vessel occlusions 2. Pregnancy 3. Severe contrast allergy or absolute contraindication to iodinated contrast agent 4. Patient has a severe or fatal combined illness that will prevent improvement of follow-up or will render the procedure unlikely to benefit the patient.