Evaluation of Endovascular Treatment in Acute Intracranial Distal Medium Vessel Occlusion Stroke

Inclusion Criteria:

1. Age ≥18 years (no upper age limit).

2. Evidence of a primary (e.g., not secondary to EVT of proximal vessel occlusion)distal medium vascular occlusion defined as occlusion of the co/non-dominant M2segment* or M3 segment of the MCA, the ACA (A1, A2, or A3 segments), or the PCA (P1,P2 or P3 segments) resulting in significant clinical deficits and expected to betreatable by endovascular thrombectomy.

• Co/non-dominant M2 segment vessel diameter should not exceed 2.0 mm. Co-dominantsupplying 50% of the MCA territory vs non-dominant supplying <50% of the MCAterritory.

3. Premorbid mRS ≤ 2.

4. Baseline National Institutes of Health Stroke Scale (NIHSS) score ≥6 at the time ofrandomization.

5. Time from onset (or time last seen well) to randomization<24 hours.

6. For patients with more than 6 hours of onset (or time last seen well),Clinical-Imaging mismatch assessment defined as any of the following scenarios (A orB): A. Non-contrast CT of the head or Brain MRI DWI lesion with <50% involvement of thevascular territory corresponding to the clinical manifestation: B. Target Mismatch Profile on CT perfusion or MRI (Mismatch Volume >10cc andmismatch Ratio >1.4 ).

7. Informed consent obtained from patient or acceptable patient surrogate.

Exclusion Criteria:

1. Any sign of intracranial hemorrhage on baseline CT/MR (SDH/SAH/ICH).

2. Rapidly improving symptoms, particularly if in the judgment of the managingclinician that the improvement is likely to result in the patient having an NIHSSscore of <6 at randomization.

3. Significant ischemic changes in a territory other than the occluded site that in theopinion of the investigator could reduce the benefit of endovascular treatment.

4. Contra indication to imaging with MR or CT with contrast agents.

5. Any terminal illness such that patient would not be expected to survive more than 1year.

6. Recent past history or clinical presentation of ICH, subarachnoid hemorrhage (SAH),arterio-venous (AV) malformation, aneurysm, or cerebral neoplasm other thanmeningioma.

7. Any imaging findings suggestive of futile recanalization in the judgment of thelocal investigator.

8. seizures at stroke onset if it precludes obtaining an accurate baseline NIHSS.

9. Baseline blood glucose of <50 mg/dL (2.78 mmol) or >400 mg/dL (22.20 mmol).

10. Known history of hereditary or acquired hemorrhagic diathesis and/or platelet count <50×109/L.

11. Known renal failure as defined as serum creatinine levels > 260umol/l（3.0 mg/dL）.

12. Presumed septic embolus or suspicion of bacterial endocarditis.

13. Any other condition that, in the opinion of the investigator could impose hazards tothe patient or affect the participation of the patient in the study if anendovascular procedure was performed.

14. History of drug or alcohol use or dependence that, in the opinion of the siteinvestigator, would interfere with adherence to study requirements.

15. Subjects with occlusions in multiple vascular territories (e.g., bilateral ormulti-territorial anterior circulation, or anterior/posterior circulation)

16. Subject participating in a study involving an investigational drug or device thatwould impact this study.

17. Known pregnancy.

18. Prisoner or incarceration