The purpose of this study is to assess the safety and device success of the Edwards SAPIEN 3 Transcatheter Heart Valve (S3 THV) and the Edwards Commander and Certitude Delivery Systems in patients with symptomatic, severe aortic stenosis who are indicated for aortic valve replacement.

This is a non-randomized, prospective, multicenter safety and device success study. Two hundred fifty (250) patients are planned to be enrolled at up to 20 participating investigational centers in Europe and Canada. Patient participation will last for a minimum of 5 years. Patients will be assessed at the following intervals: baseline, hospital discharge, 30 days, 1 year and annually thereafter for a minimum of 5 years.

Inclusion Criteria:

1. Severe symptomatic calcific aortic valve stenosis with:

   1. High surgical risk: STS Score ≥ 8 or EuroSCORE ≥ 15 (first 50 patients),
   2. High to Intermediate surgical risk: STS Score ≥ 4 or EuroSCORE ≥ 10 (patients 51 to 150).
   3. Intermediate surgical risk: STS Score 4 to 8 or Logistic EuroSCORE 10 to 15 (subsequent patients); except for 20mm valve implants (STS Score > 4 or EuroSCORE ≥ 10).

2. Age ≥ 75 years

3. NYHA ≥ II

4. Heart team (including examining cardiac surgeon) agrees on eligibility including assessment that TAVR is appropriate.

5. Study patient has provided written informed consent to comply with all of the study procedures and follow-up visits.

Exclusion Criteria:

1. Non-calcified aortic valve
2. Acute myocardial infarction ≤ 30 days before the intended treatment
3. Untreated clinically significant coronary artery disease requiring revascularization.
4. Aortic valve is a congenital unicuspid or congenital bicuspid valve.
5. Mixed aortic valve disease (with predominant aortic regurgitation)
6. Preexisting bioprosthetic valve or ring in any position
7. For Intermediate Risk patients enrolled under inclusion criterion 1.c) patients with untreated pre-existing conduction disturbances (AV Block and Bundle Branch Block).