Safety and Efficacy of SYM-SV/DS-002 in Patients With Severe Aortic Stenosis

Inclusion Criteria: 1. At least one cardiologist and one cardiac surgeon agree that it is difficult for the patient to receive a surgical procedure due to medical factors such that the subject has various comorbidities and he/she is more likely to die or suffer from severe diseases than to have significant improvements by a surgical procedure. 2. Subject has senile degenerative aortic valve stenosis with: * mean gradient \> 40 mmHg, or maximum jet velocity greater than 4.0 m/sec by either resting or dobutamine stress echocardiogram, or simultaneous pressure recordings at cardiac catheterization * AND an initial aortic valve area of ≤ 0.8 cm2 (or aortic valve area index ≤ 0.5 cm2/m2) by resting echocardiogram or simultaneous pressure recordings at cardiac catheterization 3. Subject is symptomatic from his/her aortic valve stenosis (AS), as demonstrated by New York Heart Association (NYHA) Functional Class II or greater. 4. The subject has been informed of the nature of this trial, agrees to its provisions and has provided written informed consent as approved by the IRB of the respective clinical site. 5. The subject or the subject's legal representative agrees to visit the site where he/she receives index procedure for all required post-procedure follow-ups. Exclusion Criteria: 1. Evidence of an acute myocardial infarction ≤ 30 days (The procedure day is counted as day 0.) before the implant procedure 2. Any percutaneous coronary or peripheral interventional procedures, including placements of bare metal stents are performed within 30 days prior to the implant procedure, or any drug eluting stents are placed within 6 months (One month is counted as 30 days.) prior to the implant procedure 3. Untreated clinically significant coronary artery disease (CAD) requiring revascularization 4. Blood dyscrasias as defined: leukopenia (WBC \< 1,000/mm3), thrombocytopenia (platelet count \<50,000 cells/mm3), history of bleeding diathesis or coagulopathy 5. Cardiogenic shock manifested by low cardiac output, vasopressor dependence, or mechanical hemodynamic support 6. Need for emergency surgery for any reason 7. Severe ventricular dysfunction with left ventricular ejection fraction (LVEF) \< 20% as measured by resting echocardiogram 8. Cerebrovascular accident (CVA) or transient ischemic attack (TIA) within 6 months prior to the implant procedure (except mild TIA related to aortic stenosis) 9. End stage renal disease requiring chronic dialysis or serum creatinine \> 3.0 mg/dL 10. Active Gastrointestinal (GI) bleeding within 3 months prior to the implant procedure 11. A known hypersensitivity or contraindication to any of the following which cannot be adequately pre-medicated: * Aspirin * Heparin (HIT/HITTS) * Nitinol (titanium or nickel) * P2Y12 inhibitors (such as Ticlopidine etc.) * Contrast media 12. Ongoing sepsis, including active endocarditis 13. Subject refuses a blood transfusion 14. Life expectancy \< 12 months due to associated non-cardiac comorbid conditions 15. Other medical, social, or psychological conditions that in the opinion of a principal investigator or sub-investigator precludes the subject from appropriate consent 16. Severe dementia (unable to provide informed consent for the treatment/procedure, unable to live an independent life outside of a chronic care facility, or expected to be fundamentally unable to undergo rehabilitation after the procedure, or unable to come to the site for follow-up visits) 17. Currently participating in other trials of investigational drugs or other investigational devices 18. Native aortic annulus size \< 21 mm or \> 27 mm per the baseline diagnostic imaging 19. Pre-existing prosthetic heart valve and / or prosthetic ring in any position 20. Mixed aortic valve disease (aortic stenosis and predominant aortic regurgitation (3-4+)) 21. Moderate to severe (3-4+) or severe (4+) mitral regurgitation or severe (4+) tricuspid regurgitation 22. Moderate to severe mitral stenosis 23. Hypertrophic obstructive cardiomyopathy 24. New or untreated echocardiographic evidence of intracardiac mass, thrombus or vegetation 25. Congenital bicuspid or unicuspid valve verified by echocardiograph 26. Extreme eccentric calcification of the native aortic valve 27. Transesophageal echocardiogram (TEE) is contraindicated. 28. Scheduled surgical or percutaneous procedure to be performed prior to 1-month visit post-implant procedure 29. Hepatic failure (Child C or more) 30. Aortic or peripheral condition NOT appropriate for transfemoral implant due to the size, disease and degree of calcification or tortuosity of the aorta or ilio-femoral arteries 31. Thoracic or abdominal aortic aneurysm 32. Woman who is pregnant, breastfeeding or willing to become pregnant