Safety and Performance Study of the Edwards CENTERA Self-Expanding Transcatheter Heart Valve.

1. Heart team (including at least a cardiac surgeon and an interventional cardiologist) agrees on eligibility including assessment that TAVI is appropriate.
2. High surgical risk: 8 <= STS Score <= 15 or 15 <= Logistic EuroSCORE I <= 40.
• if STS score is below 8 and/or EuroSCORE is below 15,the Heart Team must document other clinical or anatomical risk factors for which the patient would be considered high risk for surgery.
3. NYHA >= II.
4. Severe symptomatic aortic stenosis requiring aortic valve replacement characterized by AVA <= 1cm2 (or indexed AVA <0.6 cm2/m2) or mean gradient > 40mmHg (or peak aortic jet velocity > 4.0m/sec).
5. Study patient is an adult of legal consent age.
6. Study patient has provided written informed consent to comply with all of the study procedures and follow-up visits.
7. If women of childbearing age, confirmation of negative pregnancy test

1. Evidence of an acute myocardial infarction <= 1 month (30 days) before the intended treatment [(defined as: Q wave MI, or non-Q wave MI with elevation of CK-MB >= 3 times normal in the absence of pathological Q waves), if no assay for CK-MB was performed, elevation of CK level to > 2 times normal without new Q waves is also considered a non-Q wave MI)].
2. Untreated clinically significant coronary artery disease requiring revascularization.
3. Aortic valve is a congenital unicuspid or congenital bicuspid valve.
4. Mixed aortic valve disease (aortic stenosis and aortic regurgitation with predominant aortic regurgitation >3+).
5. Preexisting bioprosthetic valve or ring in any position.
6. Leukopenia (WBC < 3000 cell/µL), anemia (Hgb < 9 g/dL), Thrombocytopenia (Plt < 50,000 cell/µL), or any known blood clotting disorder.
7. Non-valvular hypertrophic cardiomyopathy with or without obstruction (HOCM).
8. Severe ventricular dysfunction with LVEF < 20%.
9. Echocardiographic evidence of intracardiac or intraaortic mass, thrombus or vegetation.
10. Active upper GI bleeding within 3 month (90 days) prior to procedure.
11. A known contraindication or hypersensitivity to all anticoagulation regimens, or inability to be anticoagulated for the study procedure.
12. Native aortic annulus size < 18 mm or > 26 mm as measured by CT.
13. Clinically (by neurologist) or neuroimaging confirmed stroke or transient ischemic attack (TIA) within 3 months (90 days) of the procedure.
14. Renal insufficiency (creatinine > 3.0 mg/dL) and/or renal replacement therapy at the time of screening.
15. Estimated life expectancy < 24 months (730 days) due carcinomas, chronic liver disease, chronic renal disease or chronic end stage pulmonary disease.
16. Expectation that patient will not improve despite treatment of aortic stenosis.
17. Currently participating in an investigational drug or another device study. Note: Trials requiring extended follow-up for products that were investigational, but have since become commercially available, are not considered investigational trials.
18. Active infection at the time of procedure and/or bacterial endocarditis within 6 months (180 days) of procedure.
19. Access vessel characteristics that would preclude safe placement of a minimum 14F sheath, which may include any of the following: severe obstructive calcification, severe tortuosity, or minimum vessel diameter less than 0.5mm.
20. Known hypersensitivity to nitinol (nickel or titanium) or contrast media that cannot be adequately premedicated.
21. PCI within one month (30 days) prior to the TAVI procedure.
22. Emergency interventional/surgical procedures within one month (30 days) prior to the TAVI procedure.
23. Severe mitral insufficiency.
24. Pregnant or breastfeeding women