The study objective is to evaluate safety and efficacy of the Medtronic TAVR (Transcatheter Aortic Valve Replacement) 2.0 system in patients with severe symptomatic aortic stenosis who are considered at high through extreme risk for surgical aortic valve replacement

Prospective, single arm, multi-site study. Patients will be seen at pre and post procedure, discharge, 30 days, 6 months, 1 year, and annually up to 5 years.

Inclusion Criteria:

1. Severe aortic stenosis, defined as aortic valve area of <1.0 cm2 (or aortic valve area index of <0.6 cm2/m2) by the continuity equation, AND mean gradient >40 mmHg OR maximal aortic valve velocity >4.0 m/sec by resting echocardiogram
2. Society of Thoracic Surgeons(STS) score of ≥8 OR documented heart team agreement of ≥ high risk for aortic valve replacement due to frailty or co-morbidities
3. Symptoms of aortic stenosis AND New York Heart Association (NYHA) Functional Class II or greater
4. The subject and the treating physician agree that the subject will return for all required post procedure follow-up visits.

Exclusion Criteria:

1. Any condition considered a contraindication for placement of a bioprosthetic valve (eg, subject is indicated for mechanical prosthetic valve)

2. A known hypersensitivity or contraindication to any of the following which cannot be adequately pre medicated:

   • aspirin or heparin (HIT/HITTS) and bivalirudin
   • ticlopidine and clopidogrel
   • nitinol (titanium or nickel)
   • contrast media

3. Blood dyscrasias as defined: leukopenia (WBC <1000 mm3), thrombocytopenia (platelet count <50,000 cells/mm3), history of bleeding diathesis or coagulopathy, or hypercoagulable states

4. Untreated clinically significant coronary artery disease requiring revascularization

5. Severe left ventricular dysfunction with left ventricular ejection fraction (LVEF) <20% by echocardiography, contrast ventriculography, or radionuclide ventriculography

6. End stage renal disease requiring chronic dialysis or creatinine clearance <20 cc/min.

7. Ongoing sepsis, including active endocarditis

8. Any percutaneous coronary or peripheral interventional procedure with a bare metal or drug eluting stent performed within 30 days prior to study procedure

9. Symptomatic carotid or vertebral artery disease or successful treatment of carotid stenosis within 10 weeks of Heart Team assessment

10. Cardiogenic shock manifested by low cardiac output, vasopressor dependence, or mechanical hemodynamic support

11. Recent (within 6 months of Heart Team assessment) cerebrovascular accident (CVA) or transient ischemic attack (TIA)

12. Gastrointestinal (GI) bleeding that would preclude anticoagulation

13. Subject refuses a blood transfusion

14. Severe dementia (resulting in either inability to provide informed consent for the study/procedure, prevents independent lifestyle outside of a chronic care facility, or will fundamentally complicate rehabilitation from the procedure or compliance with follow-up visits)

15. Estimated life expectancy of less than 12 months due to associated non-cardiac co-morbid conditions

16. Other medical, social, or psychological conditions that in the opinion of the investigator precludes the subject from appropriate consent or adherence to the protocol required follow-up exams

17. Currently participating in an investigational drug or another device study (excluding registries)

18. Evidence of an acute myocardial infarction ≤30 days before the study procedure

19. Need for emergency surgery for any reason

20. Liver failure (Child-Pugh class C)

21. Subject is pregnant or breast feeding

22. Pre existing prosthetic heart valve in any position

23. Mixed aortic valve disease (aortic stenosis with severe aortic regurgitation)

24. Severe mitral regurgitation

25. Severe tricuspid regurgitation

26. Moderate or severe mitral stenosis

27. Hypertrophic obstructive cardiomyopathy

28. Echocardiographic or Multi-Slice Computed Tomography (MSCT) evidence of intracardiac mass, thrombus, or vegetation

29. Congenital bicuspid or unicuspid valve verified by echocardiography

30. Access vessel diameter <5.5 mm or <6.0 mm for patent left internal mammary artery (LIMA)

All events 6 months, All Cause Mortality 60 months