The purpose of this trial is to determine the safety and effectiveness of the Edwards SAPIEN 3 transcatheter heart valve and delivery systems which are intended for use in patients with symptomatic, calcific, severe aortic stenosis, and are in high risk.

This is a prospective, non-randomized, multi-center trial for patients undergoing aortic valve replacement with the Edwards SAPIEN 3 THV for severe aortic stenosis. Patient cohorts will include those inoperable and those considered as a high surgical risk (STS ≥8%). The study also includes NR7 patients (patients with a 20mm vessel size).

Inclusion Criteria:

1. Patient has senile degenerative aortic valve stenosis with echocardiographically derived criteria: mean gradient >40 mmHg or jet velocity greater than 4.0 m/s and an initial aortic valve area (AVA) of ≤0.8 cm2 or indexed EOA < 0.5 cm2/m2. Qualifying echo must be within 60 days of the date of the procedure.
2. Patient is symptomatic from his/her aortic valve stenosis, as demonstrated by NYHA Functional Class II or greater.
3. The heart team agrees (and verified in the case review process) that valve implantation will likely benefit the patient.
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 Institutional Review Board (IRB) of the respective clinical site.
5. The study patient agrees to comply with all required post-procedure follow-up visits including annual visits through 5 years and analysis close date visits, which will be conducted as a phone follow-up.
6. STS > 8

Exclusion Criteria:

1. Pre-existing mechanical or bioprosthetic valve in any position.
2. Active bacterial endocarditis within 6 months (180 days) of procedure.
3. Echocardiographic evidence of intracardiac mass, thrombus or vegetation.
4. Any therapeutic invasive cardiac procedure resulting in a permanent implant that is performed within 30 days of the index procedure. Implantation of a permanent pacemaker or ICD is not considered exclusion criteria.
5. Aortic valve is a congenital unicuspid or congenital bicuspid valve, or is non-calcified.