We will conduct a multicenter, prospective, randomized, open-label, blinded endpoint trial with a non-inferiority design in patients who present 6 to 24 hours after symptom onset with LVO. Patients who meet eligibility criteria will be randomly assigned to the Non-perfusion or Perfusion group with a 1:1 ratio. In the Non-perfusion group, patients with penumbra-core mismatch (defined as the FLAIR Vascular Hyperintensity (FVH) extending beyond the boundary of the DWI cortical lesions) will receive EVT. In the Perfusion group, patients with perfusion mismatch (defined as regional cerebral blood flow (\<30%) \< 70 ml with mismatch ratio ≥ 1.8 and mismatch volume ≥ 15 ml) will receive EVT. Patients in both groups will receive guideline-based medical treatment. If patients in both groups do not meet the criteria for EVT, only guideline-based medical treatment will be administered.
Age of 18 years or older；
Anterior circulation LVO (internal carotid artery, or middle cerebral arteries (MCA)M1, M2 proximal segment) confirmed by computed tomographic angiography (CTA)/magnetic resonance angiography (MRA)；
NIHSS score ≥6 at the time of randomization；
ASPECTS score ≥ 6 on NCCT；
Pregnancy, or those potential with positive urine or serum beta Human Chorionic Gonadotrop in test；
A history of severe allergy to contrast media；
Uncontrolled hypertension (SBP >185mmHg; DBP>110mmHg)；
Hereditary or acquired bleeding tendency, coagulation factor deficiency, recent anticoagulant medication (A platelet count of less than 100 x 109 /L；INR>3 or PPT more than 3 times normal)；