Carotid angioplasty and stenting (CAS) is an effective treatment for carotid artery stenosis but carries a risk of cerebral embolization. This prospective randomized study evaluates the safety and efficacy of proximal embolic protection using a balloon guide catheter during CAS by comparing the incidence of diffusion-weighted MRI-detected microembolisms and symptomatic thromboembolic events between protected and unprotected procedures.

Inclusion Criteria:

• Age ≥ 18 years
• Symptomatic or asymptomatic carotid artery stenosis
• Candidate for carotid artery stenting
• Written informed consent provided

Exclusion Criteria:

• Vascular anatomy unsuitable for balloon guide catheter placement
• Severe renal failure
• Previous disabling stroke or symptomatic intracranial hemorrhage
• Evidence of carotid thrombus
• Severe common carotid artery lesion
• Chronic atrial fibrillation on oral anticoagulation
• Acute coronary syndrome within 30 days
• Contraindications to anticoagulant or antiplatelet therapy
• Contraindications to MRI
• Contrast media allergy
• Lack of prior dual antiplatelet therapy

Outcome assessors (neurologists and radiologists evaluating diffusion-weighted MRI images) are blinded to treatment allocation. Participants and interventional staff are not blinded due to the nature of the procedure.