This trial will provide valuable insights into the safety and efficacy of endovascular treatment for acute ischemic stroke patients with basilar artery occlusion within 8 hours of estimated occlusion time.

This clinical trial is designed to compare the safety and efficacy of endovascular treatment plus standard medical therapy with standard medical therapy alone for acute BA occlusion presented within 8 h of estimated occlusion time. There is only one ongoing clinical trial-Basilar Artery International Cooperation Study (BASICS) (NCT01717755) aimed to evaluate the efficacy and safety of additional intra-arterial treatment after intravenous treatment in 750 patients with BA occlusion, which was anticipated to be completed in Oct 2017. Initiation of intra-arterial therapy should be feasible within 6 hours of estimated time of BA occlusion. And patients are required to have an NIHSS ≥ 10 at time of randomization, and take IV rt-PA, age between 18-85 years old.

In this trial, the investigators did not have age or NIHSS score limit, patients who did not fulfill the requirements for IV rt-PA can also be included into the trial, the investigators also extended the time window to 8 hours which will accelerate the recruitment of potential subjects. In endovascular treatment arm, the time interval between randomization to procedure finish will be controlled within 120 mins. The preparation of endovascular treatment will start immediately after randomization for those eligible patients for IV rt-PA within 4.5 hours after acute stroke onset, with no need to wait for the one-hour rt-PA infusion. A positive trial will suggest substantial clinical benefit from endovascular treatment plus standard medical therapy over standard medical therapy. This trial may provide novel evidence of adopting endovascular treatment for acute patients with BA occlusion, which may consequently advance our current approach for acute stroke treatment.

Inclusion Criteria:

1. Age ≥18 years;
2. Acute ischemic stroke consistent with infarction in the basilar artery territory;
3. Basilar artery occlusion confirmed by CTA/MRA/DSA, within 8 hours of estimated occlusion time;
4. Written informed consent from patient or surrogate, if unable to provide consent.

Exclusion Criteria:

1. Computed tomography (CT) or Magnetic Resonance Imaging (MRI) evidence of Cerebral hemorrhage on presentation;
2. Premorbid mRS ≥ 3 points;
3. Currently in pregnant or lactating;
4. Known serious sensitivity to radiographic contrast agents and nitinol metal;
5. Current participation in another investigation drug or device study;
6. Uncontrolled hypertension defined as systolic blood pressure > 185 mmHg or diastolic blood pressure > 110 mmHg that cannot be controlled except with continuous parenteral antihypertensive medication;
7. Known hereditary or acquired hemorrhagic diathesis, coagulation factor deficiency; or oral anticoagulant therapy with INR >1.7 or institutionally equivalent prothrombin time;
8. Baseline lab values: glucose < 50 mg/dl or > 400 mg/dl, platelets <100*109/L, or Hct<25%;
9. Arterial tortuosity that would prevent the device from reaching the target vessel;
10. Life expectancy less than 1 year;
11. History of major hemorrhage in the past 6 months;
12. Angiographic evidence of significant cerebellar mass effect or acute hydrocephalus.
13. Angiographic evidence of bilateral extended brainstem ischemia.