Intra-arterial Thrombolysis for Acute Ischemic Stroke With Medium Vessel Occlusion

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