Exploring the Efficacy and Safety of Emergent Endovascular Treatment in Patients with Mild Ischemic Stroke Caused by Acute Anterior Circulation Large Vessel Occlusion based on Perfusion Imaging Screening

This study aims to select suitable patients with mild AIS caused by anterior circulation LVO with mismatch volume of the ischemic penumbra based on screen of cerebral perfusion imaging. It is a prospective, multicenter, endpoint-blinded, randomized controlled trial design, and aim to explore the efficacy and safety of EVT for mild AIS patients with anterior circulation large vessel occlusion within 24 hours of onset.

Inclusion Criteria

1. Age 18-80 years old;
2. Symptoms onset or last known well to randomization is within 24 hours.
3. Clinical diagnosis of acute ischemic stroke due to anterior circulation intracranial large vessel occlusion (LVO) (including intracranial internal carotid artery [ICA], middle cerebral artery [MCA] M1 segment, MCA M2 segment, with or without ipsilateral extracranial ICA occlusion) confirmed on Computerized tomography angiography (CTA) or Magnetic resonance imaging angiography (MRA) ;
4. Baseline NIHSS score <6 before randomization (including cases with NIHSS ≥6 at onset but improves before randomization);
5. ASPECTS score ≥6 based on Non-contrast CT (NCCT) before randomization, and computerized tomography perfusion (CTP) or magnetic resonance imaging perfusion (MRP) imaging presented infarct core volume (relative cerebral blood flow (rCBF) <30%/DWI-ADC<620) ≤50ml, and mismatch volume (Tmax>6 seconds volume - rCBF <30% /DWI-ADC<620) ≥50mL;
6. The patient or their legal representatives voluntarilysigned the informed consent form.

Clinical Exclusion Criteria

1. Premorbid Rankin Scale (mRS) score ≥ 1;
2. Known allergy to iodine, heparin, anaesthesia, or other definite contraindication to receiving endovascular treatment (EVT) procedure;
3. Patient has severe or fatal co-morbidities that could interfere with outcome assessments and follow-up (such as malignant tumor, severe heart failure, or renal failure, or life expectancy less than 6 months);
4. Poorly controlled hypertension (systolic blood pressure >220 mmHg or diastolic blood pressure >120 mmHg);
5. Baseline blood glucose <50mg/dL (2.78 mmol/L) or >400mg/dL (22.20 mmol/L);
6. Known bleeding tendencies, including but not limited to platelet count <100×109/L; received heparin treatment within 48 hours with an activated partial thromboplastin time (APTT) ≥35s; recent oral anticoagulant therapy with international normalized ratio (INR) >3; Note: Patients without a history of coagulation abnormalities or without suspicion of coagulation abnormalities do not need to wait for laboratory test results before enrollment;
7. Seizures at stroke onset or during the course, hard to accurately judge the baseline NIHSS score;
8. Female who is known to be pregnant, lactation, or tested positive for pregnancy at time of admission;
9. Currently participating in another investigational drug study or medical device treatments that may interfere with the results of this study;
10. Other conditions deemed unsuitable for participation, in the opinion of the investigator, or that may pose significant risks to the patient if participating the study.

Imaging Exclusion Criteria:

1. Evidence of intracranial hemorrhage on CT/MRI, including cerebral parenchymal hemorrhage, intraventricular hemorrhage, subarachnoid hemorrhage, and subdural/extradural hemorrhage;
2. Significant midline displacement, hernia of brain, or ventricular mass effect with midline displacement confirmed on CT/MRI;
3. Anticipated impossibility to complete endovascular treatment, such as vascular tortuosity, severe vascular wall calcification, etc.;
4. Aortic dissection;
5. Multiple intracranial large vessel occlusions confirmed by CTA or MRA, unable to clearly identify the symptomatic vessel, such as bilateral MCA occlusions or occlusions involving both the MCA and basilar artery;
6. Suspected or confirmed occluded artery is non-acute occlusion.

Endpoint-blined