ENVISION IDE Trial: Safety and Effectiveness of NAVITOR in Transcatheter Aortic Valve Implantation

Key Inclusion Criteria:

1. Subject who is deemed to be at intermediate or low risk for open surgical aorticvalve replacement:

2. Intermediate risk: estimated risk of overall surgical mortality ≥ 3% and < 8%at 30 days

3. Low risk: estimated risk of overall surgical mortality < 3% at 30 daysEstimated risk of overall surgical mortality includes consideration of theSociety of Thoracic Surgeons (STS) risk score, overall clinical status, andother clinical co-morbidities unmeasured by the risk calculator

4. New York Heart Association (NYHA) Functional Classification of II, III, or IV

5. Degenerative aortic valve stenosis

Key Exclusion Criteria:

1. In the opinion of the Investigator, life expectancy is less than 2 years

2. Evidence of an acute myocardial infarction [defined as ST-segment elevationmyocardial infarction (STEMI) or non-ST-segment elevation myocardial infarction (NSTEMI) with acute ischemia symptoms and troponin elevation] within 30 days priorto index procedure

3. Untreated clinically significant coronary artery disease requiring revascularization

4. Any percutaneous coronary or peripheral interventional procedure performed within 30days prior (except pacemaker or implantable cardioverter defibrillator (ICD)implant) to index procedure or planned within 30 days following the index procedure

5. Blood dyscrasias as defined: leukopenia (WBC < 3000 mm3), acute anemia (Hb < 9g/dL), thrombocytopenia (platelet count < 50,000 cells/mm³); history of bleedingdiathesis or coagulopathy

6. Active peptic ulcer or upper GI bleeding within 3 months prior to index procedurethat would preclude anticoagulation

7. Recent (within 6 months prior to index procedure date) cerebrovascular accident (CVA) or a transient ischemic attack (TIA)

8. Renal insufficiency (creatinine > 3.0 mg/dL or eGFR < 30 ml/min/1.73m2) and/or endstage renal disease requiring chronic dialysis

9. Hostile chest or conditions or complications from prior surgery that would make thesubject be considered high surgical risk (i.e., mediastinitis, radiation damage,abnormal chest wall, porcelain aorta, adhesion of aorta or internal mammary arteryto sternum, etc.)

10. Significant frailty as determined by the heart team (after objective assessment offrailty parameters) that would indicate high or extreme surgical risk

11. Mixed aortic valve disease (aortic stenosis and aortic regurgitation withpredominant aortic regurgitation 3-4+)

12. Aortic valve is a unicuspid or bicuspid valve as verified by echocardiography or CT.

13. Severe ventricular dysfunction with LVEF < 30% as measured by resting echocardiogram

14. Pre-existing prosthetic heart valve or other implant (such as prosthetic ring ortranscatheter edge-to-edge repair (TEER) clip) in any valve position

15. Severe circumferential mitral annular calcification (MAC) which is continuous withcalcium in the left ventricular outflow tract (LVOT)

16. Severe (greater than or equal to 3+) mitral regurgitation or severe mitral stenosis

17. Minimum access vessel diameter of < 5.0 mm for small FlexNav Delivery System and < 5.5 mm for large FlexNav Delivery System

18. Eccentricity ratio of the annulus < 0.73

Additional Exclusion Criteria for Pivotal Randomized Cohort

1. Hostile Chest or conditions or complications from prior surgery that would make thesubject be considered high surgical risk

2. Significant frailty as determined by the heart team (after objective assessment offrailty parameters) that would indicate high or extreme surgical risk

3. Mixed aortic valve disease

4. Aortic valve is a unicuspid or bicuspid valve as verified by echocardiography or CT

5. Inadequate aortic valve calcification

6. Pre-existing prosthetic heart valve or other implant (such as prosthetic ring ortranscatheter edge-to-edge repair (TEER) clip) in any valve position

Additional Exclusion Criteria for ViV Cohort

1. Failing valve has moderate or greater paravalvular regurgitation.

2. Known severe prosthesis-patient mismatch

3. Failing valve is unstable, rocking, or not structurally intact.

4. Patient has a pre-existing prosthetic heart valve or other implant (such aprosthetic ring with a rigid support structure or transcatheter edge-to-edge repairclip) in any valve position other than aortic.

5. Bioprosthetic valve diameter that would not accommodate implantation of the NavitorValve.

6. Increased risk of coronary obstruction by prosthetic leaflets of the index valve