A Clinical Trial of the Transcatheter Aortic Valve Implantation System With a Prospective, Multi-Center, One-Arm Approach to Evaluate the Efficacy and Safety in the Treatment of Patients With Severe Aortic Stenosis

Inclusion Criteria: * Contraindication to surgery, or high risk for surgery (STS ≥ 8%) as assessed by the heart team; or other circumstances that make surgical valve replacement inappropriate. * Age ≥65 years. * Patients with symptomatic severe aortic stenosis (mean aortic transvalvular gradient by echocardiography ≥40 mmHg (1 mmHg=0.133 kPa), or transaortic flow velocity ≥4.0 m/s, or aortic valve orifice area \<0.8 cm2, or effective aortic orifice area index \<0.5 cm2 /m2). * The subjects have been informed of the nature of this study, understand the purpose of the clinical trial, and voluntarily participate in and sign the informed consent form. Exclusion Criteria: * Life expectancy less than 1 year after implantation of the prosthetic valve. * Patients had an acute heart attack within 1 month, or had a coronary stent or a pacing device implantation within 1 month, or had any therapeutic cardiac surgery within 1 month. * Patients with aortic root anatomy and lesion that are not suitable for prosthetic valve implantation. * Combined with severe insufficiency or stenosis of other valves and requiring surgical treatment. * Hematologic cachexia, including leukopenia (WBC \<3×10\^9 /L), acute anemia (HB \<90 g/L), thrombocytopenia (PLT \<50 × 10\^9 /L), bleeding constitution, and coagulation disorders. * Untreated coronary artery disease requiring hematologic reconstruction. * Hypertrophic obstructive cardiomyopathy. * Severe left ventricular dysfunction with left ventricular…