PROGRESS: Management of Moderate Aortic Stenosis by Clinical Surveillance or TAVR

Key Inclusion Criteria: 1. 65 years of age or older at time of randomization 2. Moderate aortic stenosis 3. Subject has symptoms or evidence of cardiac damage/dysfunction 4. The subject or subject's legal representative has been informed of the nature of the study, agrees to its provisions, and has provided written informed consent. Key Exclusion Criteria: 1. Native aortic annulus size unsuitable for the THV 2. Anatomical characteristics that would preclude safe transfemoral placement of the introducer sheath or safe passage of the delivery system 3. Aortic valve is unicuspid or non-calcified 4. Bicuspid aortic valve with an aneurysmal ascending aorta \> 4.5 cm or severe raphe/leaflet calcification 5. Pre-existing mechanical or bioprosthetic aortic valve 6. Severe aortic regurgitation 7. Prior balloon aortic valvuloplasty to treat severe AS 8. LVEF \< 20% 9. Left ventricular outflow tract calcification that would increase the risk of annular rupture or significant paravalvular leak post-TAVR 10. Cardiac imaging evidence of intracardiac mass, thrombus, or vegetation 11. Coronary or aortic valve anatomy that increases the risk of coronary artery obstruction post-TAVR