VitaFlow™ Transcatheter Aortic Valve System Pre-market Trial

Inclusion criteria : Enrollment was limited to patients who met all of the following criteria: 1. Age ≥ 70 years old(Phase II)/Age ≥18 years old,male or female who are not pregnant (Phase I); 2. Patients have severe aortic stenosis: Mean gradient\> 40mmHg(1mmHg = 0.133kPa), or peak velocity\> 4m/s, or an aortic valve area(AVA) \<1.0 cm² (or AVA index \<0.6 cm²/m²); 3. NYHA classification ≥ II; 4. Life expectancy\> 12 months; 5. Anatomically suitable for transcatheter aortic valve implantation; 6. Assessed by a multidisciplinary heart team as a patient unsuitable for surgical aortic valve replacement; 7. Patients who can understand the purpose of the investigation, volunteer to participate in and sign the informed consent form, and are willing to comply with relevant examinations and follow-up visits. Exclusion criteria: 1. Acute myocardial infarction occurred within 30 days before the treatment; 2. Patients with congenital unicuspid aortic valve or aortic root anatomy and lesions that are not suitable for transcatheter valve implantation; 3. Any therapeutic heart surgery within 30 days; 4. Mixed aortic valve disease(aortic stenosis with severe regurgitation); moderate and severe mitral stenosis; severe mitral regurgitation; severe tricuspid regurgitation; 5. Blood dyscrasia, including neutropenia (WBC \< 3 × 10\^9/L), acute anemia(HB \<90 g/L), thrombocytopenia(PLT \<50 × 10\^9/L), hemorrhagic constitution, and coagulopathy disease; 6. Untreated coronary artery disease requiring revascularization; 7. Hemodynamic instability requiring systolic support or mechanical heart assistance; 8. Need for emergency surgery for any reason; 9. Obstructive hypertrophic cardiomyopathy; 10. Severe left ventricular dysfunction, left ventricular ejection fraction(LVEF) \< 20%; severe pulmonary hypertension and right ventricular dysfunction; 11. Echocardiography suggests the presence of intracardiac masses, thrombi, or neoplasms; 12. Active peptic ulcer or history of upper gastrointestinal bleeding within 3 months; 13. Allergy to aspirin, heparin, ticlopidine, clopidogrel, nitinol, or contrast agents; 14. Cerebrovascular events including transient ischemic attack(TIA) occurred within 6 months; 15. Renal insufficiency decompensation(end creatinine clearance \< 20ml/min), and / or end-stage renal disease require long-term dialysis treatment; 16. Vascular diseases affecting device access; 17. Active infectious endocarditis or other active infection; 18. Participated in clinical investigations of other drugs or medical devices before the election, and had not completed the primary endpoint; 19. The investigator judged that the patient had poor compliance and could not complete the study as required.