Acute ischemic stroke (AIS) due to medium vessel occlusion (MeVO) or severe stenosis poses a significant clinical challenge. Recent large randomized controlled trials, DISTAL and ESCAPE-MeVO, demonstrated no significant benefit of endovascular therapy in patients with MeVO. Although intra-arterial thrombolysis has shown promise in clinical experience, robust evidence supporting its efficacy in MeVO or severe stenosis-related AIS is still absent. To fill this gap, the RESCUE MeVO trial has been designed as a multicenter, prospective, randomized, open-label, blinded end-point (PROBE) study to evaluate the efficacy and safety of intra-arterial thrombolysis in patients with AIS caused by MeVO or severe stenosis.

This study is a multicenter, prospective, randomized, open-label, blinded end-point (PROBE) trial. Eligible participants will be adults (age >18 years) presenting with acute ischemic stroke (AIS) due to MeVO or severe stenosis (≥70%). Participants who meet all inclusion criteria and none of the exclusion criteria will be randomly assigned in a 1:1 ratio to one of two treatment arms. The control group will receive best medical management alone, while the intervention group will receive best medical management in combination with intra-arterial thrombolysis. Intra-arterial thrombolysis is performed by infusing rhTNK-tPA (Tenecteplase) proximal to the occlusion or severe stenosis for 5-30 minutes, with the decision to continue beyond the first 5 minutes being guided by intraprocedural DSA. The primary objective of this study is to evaluate the efficacy and safety of intra-arterial thrombolysis in patients with acute ischemic stroke caused by MeVO or severe stenosis. The primary endpoint is excellent outcome at 90 days, defined as a score of 0-1 on the modified Rankin Scale (mRS).

Inclusion Criteria:

• Age > 18 years

• Primary medium vessel occlusion (MeVO) or severe stenosis (≥70%) was detected on CTA, MRA, or DSA, involving arterial segments including M2-M3 of the middle cerebral artery (MCA), A1-A2 of the anterior cerebral artery (ACA), P1-P2 of the posterior cerebral artery (PCA), and the anterior inferior cerebellar artery (AICA), posterior inferior cerebellar artery (PICA), and superior cerebellar artery (SCA)

• The clinical symptoms were consistent with MeVO, with a NIHSS score 5 - 25, or an NIHSS score of 3-4 in the presence of disabling neurological deficits (e.g., hemianopia, aphasia, or motor dysfunction)

• Intra-arterial thrombolysis was administered within the following time windows:

  1. Acute ischemic stroke within 24 hours of symptom onset or last known well, including stroke with known onset, wake-up stroke and stroke with unknown onset, with no obvious hypodensity on CT and good collateral circulation on CTA;
  2. Acute ischemic stroke within 24-72 hours of onset, meeting at least one of the following imaging criteria: a.CT or MR perfusion imaging demonstrating target mismatch, defined as an ischemic core volume <30 mL, a mismatch ratio ≥1.2, and a mismatch volume ≥10 mL.; b.MRI demonstrating DWI-FLAIR mismatch, defined as the presence of acute ischemic lesions on diffusion-weighted imaging (DWI) with no corresponding hyperintense signal on FLAIR, or with FLAIR hyperintense lesions occupying less than one-third of the DWI lesion volume.

• Signed informed consent obtained

Exclusion Criteria:

• Pre-stroke mRS ≥ 2
• Secondary MeVO or severe stenosis caused by endovascular therapy
• Neuroimaging demonstrated intracranial hemorrhage, subarachnoid hemorrhage, or other hemorrhagic disorders
• Non-contrast CT demonstrating a clearly hypodense lesion corresponding to the vascular territory
• Platelet count <100 × 10⁹/L, known bleeding tendency or coagulation factor deficiency, or oral anticoagulant therapy with an international normalized ratio (INR) >3.0
• Persistent and uncontrolled hypertension, defined as systolic blood pressure >185 mmHg or diastolic blood pressure >110 mmHg
• History of intracranial hemorrhage within the past 3 months, including parenchymal hemorrhage, intraventricular hemorrhage, subarachnoid hemorrhage, epidural hemorrhage, or subdural hemorrhage
• Presence of arteriovenous malformations or brain tumors with mass effect
• Gastrointestinal or urinary tract bleeding, or major surgery within the past 3 months
• Chronic dialysis or severe renal impairment, defined as a glomerular filtration rate (GFR) <30 mL/min or serum creatinine >220 μmol/L (2.5 mg/dL)
• Patients with known allergy to thrombolytic agents or their excipients
• Patients with known allergy to iodinated contrast agents or other established contraindications
• Pregnant or current breastfeeding
• Presence of severe systemic comorbidities with a life expectancy of less than 3 months
• Deemed unsuitable for participation by the investigator for any reason