To evaluate the safety and effectiveness of the SAPIEN XT (Edwards Lifesciences, Irvine, California) transcatheter heart valve implantation (TAVI) in Chinese patients with symptomatic severe calcific aortic stenosis who are considered at high risk for surgical valve replacement.

Edwards SAPIEN XT™ Transcatheter Heart Valve and NovaFlex+ delivery system will be used for this study.

Inclusion Criteria:

1. Subjects who are considered to be operable and high risk for surgical valve replacement: 8 ≤ STS Score ≤ 15 or 15 ≤ Logistic EuroSCORE ≤ 40. If STS score is below 8 and/or Logistic EuroSCORE is below 15, patients should have other clinical or anatomical risk factors that would be considered high risk for surgery and documented by the heart team.
2. Severe symptomatic aortic stenosis requiring aortic valve replacement characterized by one or more of the following within 60 days prior to the index procedure: AVA < 0.8 cm2, Indexed AVA <0.5 cm2/m2, mean gradient > 40mmHg, or peak aortic jet velocity > 4.0m/sec.
3. NYHA Functional Class II or greater.
4. The study patient or the study patient's legal representative has been informed of the nature of the study, agrees to its provisions and has provided written informed consent as approved by the EC of the respective clinical site.
5. The study patient agrees to comply with all required post procedure follow-up visits.

Exclusion Criteria:

1. Evidence of an acute myocardial infarction ≤ 1 month (30 days) before the intended treatment.
2. Aortic valve is a congenital unicuspid or is non-calcified.
3. Aortic valve is bicuspid and the patient is less than 60 years old, or the aortic valve is bicuspid with no raphe (Sievers classification type 0).
4. Anomalous coronary artery that would interfere with proper placement of the valve.
5. Mixed aortic valve disease (aortic stenosis and aortic regurgitation with predominant aortic regurgitation >3+).

30-days

All Adverse Events are site-reported.