This study is a prospective, open-label, multi-center, registry study, designed to show that rescue stenting is safe and effective for emergency large vessel occlusion (ELVO) patients who have mechanical thrombectomy failure. Participants with ELVO will initially underwent mechanical thrombectomy usig stent retriever, contact aspiration or both. After failure of mechanical thrombectomy, rescue stenting will be performed.

Inclusion Criteria:

• 1. Subjects experiencing acute ischemic stroke due to large vessel occlusion (intracranial internal carotid artery and middle cerebral artery M1 segment)
• 2. Age 19 or greater
• 3. mRS before qualifying stroke, 0 or 1
• 4. Baseline NIHSS score 4 or more
• 5. CT ASPECTS > 6 or MR ASPECTS > 5
• 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. Failure of mechanical thrombectomy with stent retriever, contact aspiration or both
• 9. Subjects who received rescue stenting after failure of mechanical thrombectomy
• 10. Anticipated life expectancy of at least 12 months
• 11. Signed informed consent for study enrollment

Exclusion Criteria:

• 1. Any contraindication to antiplatelet medication
• 2. Multiple simultaneous large vessel occlusions
• 3. Pregnancy
• 4. Severe contrast allergy or absolute contraindication to iodinated contrast agent
• 5. 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.

Patients with emergent large vessel occlusion and who have not achieved successful recanalization (defined by mTICI, 2b or 3) by mechanical thrombectomy using stent retriever or aspiration thrombectomy.