The study objective is to evaluate safety and effectiveness/performance of the Microport™ CardioFlow VitaFlow™ Transcatheter Aortic Valve System for the treatment of severe aortic stenosis in the real world settings.

This is a prospective, single-arm, multi-center, observational, post-market registry study. The purpose is to evaluate the safety, performance, and effectiveness of the VitaFlow™ Transcatheter Aortic Valve System in the real world settings.Patients will be seen at pre and post procedure, discharge, 30 days, 1 year and annually up to 5 years.

Inclusion Criteria:

• Age≥70 years;
• Symptomatic , calcified, severe, degenerative, native aortic valve stenosis : peak velocity ≥4.0m/s, or mean transvalvular gradient ≥40mmHg(1 mmHg=0.133kPa), or aortic valve area<0.8cm² (or EOA index<0.5cm²/m²);
• The patients considered to be not suitable for surgical aortic valve replacement (SAVR);
• The patient has been informed of the nature of the study, is willing to enroll in the study by signing a patient informed consent and agreeing to the scheduled follow up requirement.

Exclusion Criteria:

• Aortic root anatomy not suitable for the implantation of the transcatheter aortic valve；
• Vascular diseases or anatomical condition preventing the device access；
• Previous implantation of mechanical or bioprosthesis valve in the aortic position；
• Known hypersensitivity or contraindication to all anticoagulation/antiplatelet regimens, to nitinol, contrast media or other relevant elements；
• Ongoing sepsis, including active endocarditis；
• Estimated Life expectancy< 12 months；
• Participating in another trial and the primary endpoint is not achieved.
• Inability to comply with the clinical investigation follow-up or other requirements.

The study population includes symptomatic patients (≥70 years old ) with calcified, severe, degenerative, native aortic valve stenosis who are not suitable for the surgical aortic valve replacement as assessed by the heart team