To investigate whether using balloon guide catheter with flow arrest during mechanical thrombectomy, compared to non-flow arrest, improves the rate of first pass expanded Thrombolysis in Cerebral Infarction score (eTICI 2c-3) reperfusion for acute ischemic stroke due to internal carotid artery occlusion

Inclusion Criteria:

1. age ≥18 years;
2. Clinical diagnosis of acute ischemic stroke with internal carotid artery occlusion confirmed by imaging (CTA/MRA/DSA), including isolated intracranial internal carotid artery (I-type), internal carotid artery intracranial segment involving middle cerebral artery (L-type), or internal carotid artery intracranial segment involving middle and anterior cerebral arteries (T-type) (including tandem embolic occlusions of the internal carotid artery C1 or common carotid artery);
3. Baseline NIHSS≥6, and meeting local guidelines for mechanical thrombectomy;
4. Time from onset or last known normal to randomization within 24 hours and proceeding to mechanical thrombectomy;
5. Signed informed consent (or by legal representative).

Exclusion Criteria:

1. Pre-stroke mRS score >2
2. Intracranial hemorrhage shown on imaging;
3. Known or suspected internal carotid artery occlusion caused by dissection or atherosclerosis;
4. Vascular tortuosity preventing the use of balloon guide catheter;
5. Prior stent implantation in the target vessel that would impede the use or removal of mechanical thrombectomy devices;
6. Any other circumstances impeding mechanical thrombectomy implementation;
7. Acute occlusion of multiple vascular territories in bilateral anterior circulation or in both the anterior and posterior circulations confirmed by CTA/MRA;
8. Pregnant subjects;
9. Subjects allergic to contrast agents;
10. Subjects refusing to cooperate or unable to tolerate interventional procedures;
11. Subjects whose expected lifetime are less than 90 days;
12. Midline shift or herniation with ventricular mass effect;
13. Subjects deemed unable to participate in follow-up by investigators;
14. Other situations deemed unsuitable for balloon guide catheter use by investigators.