The purpose of this clinical trial is to evaluate the safety and efficacy of the Prizvalve Pro™ transcatheter aortic valve system in the treatment of patients with severe aortic stenosis who are at high risk of surgery or who are not suitable for surgery.

This study is a multicenter, single-arm, prospective clinical study.

Inclusion Criteria:

1. Age ≥ 65 years ;
2. Patients with symptomatic severe aortic valve stenosis (evaluated by echocardiography: transaortic valve pressure gradient ≥40mmHg (1mmHg=0.133kPa), or transaortic valve blood flow rate ≥4m/s, or aortic Valve area<1.0cm², or AVA <0.5cm² /m²);
3. Cardiac function NYHA ≥ II;
4. Life expectancy> 12 months;
5. Patients who are anatomically suitable for transcatheter aortic valve implantation;
6. Patients who have been evaluated by two or more cardiovascular surgeons as unsuitable for conventional surgery; or patients who have refused conventional surgery after adequate communication from the surgeon and who are at high risk for conventional surgery;
7. Patients who can understand the purpose of the trial and volunteer to participate in, sign the informed consent form and are willing to accept relevant examinations and clinical follow-ups.

Exclusion Criteria:

1. Acute myocardial infarction occurred within 1 month before this treatment;
2. Congenital unicuspid aortic valve;
3. Any therapeutic cardiac operation that is performed within 30 days of the index procedure (Previous PCI or implantation of a permanent pacemaker are not considered exclusion criteria);
4. Patients with other prosthetic heart valves, prosthetic rings already implanted in the heart, or severe mitral valve closure insufficiency (>3+);
5. Patients with hematologic disorders or abnormalities that make surgical treatment inappropriate;
6. Untreated severe coronary artery stenosis that requires revascularization;
7. Patients with hemodynamic or respiratory instability, requiring continuous mechanical heart assistance or mechanical ventilation;
8. Patients who need emergency surgery for any reason;
9. Patients with hypertrophic cardiomyopathy with obstruction;
10. Severe left ventricular dysfunction, left ventricular ejection fraction (LVEF) <20%;
11. Echocardiographic evidence of intracardiac mass, thrombus or vegetation;
12. Patients with left ventricular outflow tract obstruction;
13. A history of acute peptic ulcer or upper gastrointestinal bleeding within 3 months;
14. Patients who are allergy or resistance to cobalt-chromium alloy, contrast agents and related components;
15. Patients who are unable to receive anticoagulation or antiplatelet therapy;
16. Cerebrovascular accident occurred within 3 months, not including transient ischemic attack;
17. Severe aortic diseases, including abdominal aortic or thoracic aortic aneurysm, etc;
18. Active infective endocarditis or other active infections;
19. Patients who have participated in clinical trials of other drugs or medical devices before enrollment and have not yet reached the primary outcome of research;
20. The investigator judged that patient with poor compliance and could not complete the study as required.