Efficacy and Safety Study of Endovascular Treatment of Asymptomatic Carotid Artery Stenosis

Inclusion Criteria:

1. Age 40-80 years

2. Severe asymptomatic internal carotid artery stenosis (70-99%) confirmed byultrasound/CTA/DSA

3. Contralateral ICA stenosis <70%

4. No TIA/stroke related to target lesion in past 6 months

5. Declined carotid endarterectomy

6. Willing to complete 12-month follow-up

7. Signed informed consent by participant/legal representative

Exclusion Criteria:

1. symptomatic internal carotid artery stenosis in the past 6 months

2. Spontaneous intracranial hemorrhage in nearly one year

3. Patients with larger intracranial aneurysms (diameter >5 mm) who cannot undergoprior or concurrent treatment

4. Chronic occlusion without obvious symptoms of cerebral ischemic attack

5. Patients with transient or permanent neurological deficit resulting fromNeurological deficits mimicking TIA/stroke from TIA or stroke

6. Common carotid artery ostial lesion

7. Tandem lesions with severe stenosis of the ipsilateral intracranial artery

8. Patients with severe dementia

9. Internal carotid artery dissection

10. Internal carotid artery aneurysm

11. Myocardial infarction within 30 days

12. Ejection fraction <30% or New York Heart Association (NYHA) functional class III orhigher; unstable angina, characterized by angina at rest with electrocardiogramchanges

13. Cardiogenic embolism, including left ventricular aneurysm, intraluminal fillingdefects, cardiomyopathy, aortic or mitral valve-prosthetic heart valve, calcifiedaortic stenosis, infective endocarditis

14. Mitral stenosis, atrial septal defect, atrial septal aneurysm or left chamber myxoma

15. Two or more proximal or main coronary artery stenosis 70%, untreated or recanable

16. Platelets <5 * 104 / uL, INR> 1.5, bleeding time> 1min or heparin-relatedthrombocytopenia; heparin is a contraindication to antiplatelet drugs; coagulopathy

17. Poor controlled diabetes mellitus, fasting blood glucose> 22 mmol/L and ketonebody>+2

18. Malignant tumor or respiratory insufficiency, and a life expectancy of <5 years

19. Severe liver and kidney function impairment, ALT> 3 times the upper limit of normalvalue or AST> 3 times the upper limit of normal value, blood creatinine increase> 2times the upper limit of normal value

20. Contrast allergy

21. Other general anesthesia operations are required during the same period

22. Pregnant or lactating women

23. The patient does not attend the clinical trial of other drug or medical devicebefore enrollment

24. The investigator is not considered fit to participate in this clinical study

Imaging exclusion criteria:

1. Type III aortic arch

2. Severe angulation or tortuosity (≥90 degrees) of the common carotid artery orinnominate artery that prevents safe and rapid placement of a guiding catheter orlong sheath

3. Severe angulation or tortuosity of the internal carotid artery that prevents safedeployment of an embolic protection device or stent. Severe tortuosity is defined asthe presence of two or more angles ≥90 degrees within 4 cm of the stenotic lesion

4. Stenosis of the beginning or proximal end of the common carotid artery, innominateartery, distal or intracranial segment of the internal carotid artery, and thestenosis degree is greater than that of the target stenosis

5. The stenotic lesion exhibits severe circumferential calcification, defined ascalcification greater than 3 mm in thickness visible in orthogonal views duringfluoroscopy. (Note: In elderly subjects aged ≥70 years, anatomical factors such astortuosity, arch anatomy, and calcification must be assessed more carefully)