Overview

This multicenter, randomized, controlled trial evaluates a combined embolic protection strategy during carotid artery stenting (CAS). Carotid artery stenosis is a major cause of stroke. While stenting is an effective treatment, the procedure itself carries a risk of dislodging plaque debris, which can travel to the brain and cause new strokes or silent brain infarctions.

Currently, a distal filter (protection device) is standardly used to catch debris. However, it may not capture all particles. This study investigates whether adding a Balloon Guide Catheter (BGC)-which temporarily stops blood flow and allows for aspiration-to the standard filter protection is more effective than using the filter alone.

Patients with symptomatic (≥50% stenosis) or asymptomatic (≥70% stenosis) carotid artery stenosis who are scheduled for stenting will be randomly assigned to one of two groups:

1. Combined Protection Group: Receiving CAS using a Balloon Guide Catheter combined with a distal filter.
2. Standard Protection Group: Receiving CAS using a distal filter alone. The primary goal is to determine if the combined approach reduces the number of new ischemic lesions detected on brain MRI within 72 hours post-procedure. The study will also assess clinical stroke events over a 90-day follow-up period.

Eligibility

Inclusion Criteria:

1. Age 18 years or older.
2. Diagnosis of extracranial carotid artery stenosis meeting one of the following criteria (measured by DSA or CTA using NASCET criteria):

   Symptomatic: TIA or non-disabling stroke in the ipsilateral carotid distribution within the past 6 months, with stenosis ≥ 50%.

   Asymptomatic: Stenosis ≥ 70%, with indication for interventional therapy.

3. Pre-treatment Modified Rankin Scale (mRS) score of 0 to 1.
4. Scheduled for carotid artery stenting (CAS) as determined by the clinical team.
5. Signed informed consent provided by the patient or their legal representative.

Exclusion Criteria:

1. Occlusion of the contralateral internal carotid artery (ICA).
2. Severe stenosis of the contralateral common carotid artery (CCA) or internal carotid artery (ICA).
3. Occlusion of the ipsilateral external carotid artery (ECA).
4. Severe stenosis of the ipsilateral intracranial segment of the internal carotid artery.
5. Severe stenosis of the vertebrobasilar artery system (excluding non-dominant vertebral artery).
6. History of previous stenting in the head or neck vessels.
7. Presence of other cerebrovascular diseases, such as intracranial aneurysms \> 5 mm or vascular malformations.
8. Stroke onset within the last 7 days.
9. Pregnant or lactating women.
10. Known allergy to contrast media or stent materials (e.g., Nitinol).
11. Previous large cerebral infarction with sequelae that would interfere with the assessment of endpoint events.
12. Absolute or relative contraindications to antiplatelet therapy.
13. Clear risk of cardioembolism (e.g., atrial fibrillation, atrial flutter, intracardiac thrombus) or clear indication for anticoagulation therapy.
14. Life expectancy of less than 1 year.
15. Pre-existing neurological or psychiatric diseases that would confound neurological assessment (e.g., severe dementia).
16. Severe renal insufficiency (Glomerular Filtration Rate \[GFR\] \< 30 ml/min).
17. Contraindications to Magnetic Resonance Imaging (MRI).