ACURATE IDE: Safety and Effectiveness Study of ACURATE Valve for Transcatheter Aortic Valve Replacement

Inclusion Criteria: * IC1. Subject has documented severe symptomatic native aortic stenosis defined as follows: aortic valve area (AVA) ≤1.0 cm2 (or AVA index ≤0.6 cm2/m2) AND a mean pressure gradient ≥40 mmHg, OR maximal aortic valve velocity ≥4.0 m/s, OR Doppler velocity index ≤0.25 as measured by echocardiography and/or invasive hemodynamics. Note: In cases of low flow, low gradient aortic stenosis with left ventricular dysfunction (ejection fraction \<50%), dobutamine can be used to assess the grade of aortic stenosis (maximum dobutamine dose of 20 mcg/kg/min recommended); the subject may be enrolled if echocardiographic criteria are met with this augmentation. * IC2. Subject has a documented aortic annulus size of ≥20.5 mm and ≤29 mm based on the center's assessment of pre-procedure diagnostic imaging (and confirmed by the Case Review Committee \[CRC\]) and, for the Main Randomized Cohort and the Extended Durability Study, is deemed treatable with an available size of both test and control device. * IC3. For subjects with symptomatic aortic valve stenosis per IC1 definition above, functional status is NYHA Functional Class ≥ II. * IC4. Heart team (which must include an experienced cardiac interventionalist and an experienced cardiac surgeon) agrees that the subject is indicated for TAVR, is likely to benefit from valve replacement, and TAVR is appropriate. * IC5. Subject (or legal representative) understands the study requirements and the treatment procedures, and pro…