This multicenter, prospective, open-label randomized controlled trial with blinded assessment was designed to assess the efficacy and safety of endovascular treatment for progressive stroke due to vertebrobasilar artery occlusion.

This multicenter, prospective, open-label, randomized controlled trial with blinded endpoint assessment (PROBE design) was designed to evaluate endovascular treatment (EVT) in patients with progressive stroke due to vertebrobasilar artery occlusion (VBAO). Progressive stroke due to VBAO was defined as vertebrobasilar artery occlusion confirmed by CTA, MRA, or DSA, accompanied by neurological deterioration occurring between 24 hours and 14 days after symptom onset, defined as an increase of ≥4 points in the National Institutes of Health Stroke Scale (NIHSS) score resulting in a total NIHSS score ≥10 in patients with an initial NIHSS score <10. Participants will be randomly assigned in a 1:1 ratio to receive EVT plus medical therapy or medical therapy alone. The primary endpoint is the proportion of patients with good functional outcome at 90 days, defined as a modified Rankin Scale (mRS) score of 0 to 3. Secondary outcomes include the distribution of mRS scores at 90 days, all-cause mortality at 90 days, and the incidence of symptomatic intracranial hemorrhage (sICH).

Inclusion Criteria:

1. Age ≥18 years.
2. Acute ischemic stroke, with a National Institutes of Health Stroke Scale (NIHSS) score of <10 at initial symptom onset, and no prior endovascular treatment.
3. Stroke progression occurring from 24 hours to 14 days after initial symptom onset, defined as an NIHSS score of ≥10 with an increase of ≥4 points from baseline.
4. Acute basilar artery occlusion or dominant vertebral artery occlusion with contralateral occlusion or hypoplasia, confirmed by CTA, MRA or DSA.
5. Posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) of ≥6 and Pons-Midbrain Index (PMI) of ≤3 on CT or diffusion-weighted imaging (DWI).
6. Randomization within 24 hours of stroke progression.
7. Pre-stroke mRS score of 0-2.
8. Provision of signed informed consent by the patient or their legal representative.

Exclusion Criteria:

1. Any sign of intracranial hemorrhage (except microbleeds) on baseline brain imaging.
2. Imaging confirms the progression of symptoms caused by intracranial hemorrhage, brain edema, or other clear causes.
3. Extensive cerebellar infarction with significant mass effect or bilateral thalamic infarction on baseline neuroimaging.
4. Presence of untreated intracranial aneurysm, intracranial tumor (except small meningioma and aneurysms <3 mm in diameter), or intracranial arteriovenous malformation.
5. Known or highly suspected chronic responsible artery occlusion.
6. Presence of severe stenosis in the extracranial or intracranial segment of the responsible artery, arterial dissection, or excessive vascular tortuosity that may prevent successful delivery or navigation of endovascular devices.
7. Known contraindication to contrast medium (except mild rash).
8. Refractory hypertension not controlled by medication, defined as systolic blood pressure >185 mmHg or diastolic blood pressure >110 mmHg.
9. Known pregnancy or lactation, or a positive pregnancy test prior to randomization.
10. Known dementia or psychiatric disease precluding completion of neurological assessment and follow-up.
11. Life expectancy <1 year, including patients with malignancy or advanced cardiopulmonary disease.
12. Current participation in any other clinical trial of drugs or medical devices, or anticipated participation in another such trial within 3 months after enrollment.
13. Acute ischemic stroke within 48 hours after cardiovascular or cerebrovascular interventional treatment or major surgery; patients presenting >48 hours after such procedures were eligible.
14. Recent (within 1 month) gastrointestinal or genitourinary bleeding, acute myocardial infarction, or traumatic brain injury.
15. Multivessel severe stenosis or occlusion confirmed by CTA, MRA, or DSA.
16. Known or suspected central nervous system vasculitis.
17. Known hereditary or acquired bleeding diathesis, coagulation factor deficiency, current use of oral anticoagulants with an INR >1.5, or active bleeding.
18. Blood glucose <2.8 or >22.2 mmol/L; platelet count <100 × 10⁹/L; estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m² or serum creatinine ≥177 μmol/L (2.0 mg/dL).
19. Any other condition deemed by the site investigator to make the patient unsuitable for participation.