Siegel™ Transcatheter Aortic Valve Replacement System (TAVR) Early Feasibility Study

Inclusion Criteria: Subjects are eligible for entry in this study if all the following conditions are met: 1. Symptomatic, severe native aortic stenosis in subjects 50 years or older Aortic Valve Area (AVA) ≤ 1.0 cm2 or Aortic Valve Area (AVA) index ≤ 0.6 cm2/m2 and Jet velocity ≥ 4.0 m/s or mean gradient ≥ 40 mmHg or dimensionless Index \<0.25 2. New York Heart Association Functional Class ≥ 2 3. Requires aortic valve replacement and is indicated for TAVR as determined by the Heart Team (composed of an experienced interventional cardiologist and an experienced cardiac surgeon) 4. Eligible for transfemoral delivery of the Siegel TAVR 5. Native aortic annulus suitable for safe placement of Siegel 23mm or 26mm transcatheter heart valve (preprocedural measurements by Transthoracic Echocardiogram (TTE) and Computed Tomography (CT) of area derived aortic annulus diameter) 6. Understands the study requirements and the treatment procedures and provides written informed consent 7. Subject agrees to complete all required scheduled follow-up visits. Exclusion Criteria: Subjects will be excluded for entry in this study if any of the following conditions are met: Anatomical 1. Anatomy precluding safe placement of Siegel TAVR 2. Iliofemoral vessel characteristics that would preclude safe placement of the introducer sheath. 3. Pre-existing prosthetic heart valve in any position (note, mitral ring is not an exclusion). 4. Unicuspid or bicuspid aortic valve 5. Severe aortic regurgitation (\>3+) 6. Severe mitral or severe tricuspid regurgitation(\>3+) requiring intervention. 7. Moderate to severe mitral stenosis. 8. Hypertrophic obstructive cardiomyopathy 9. Echocardiographic evidence of intracardiac mass, thrombus or vegetation requiring treatment. 10. Severe basal septal hypertrophy with outflow gradient Clinical 11. Evidence of an acute myocardial infarction ≤ 30 days before enrollment. 12. Any percutaneous coronary or peripheral interventional procedure performed within 30 days prior to the index procedure 13. Blood dyscrasias as defined: leukopenia (WBC \< 3000 cell/mL, anemia (Hgb \< 9 g/dL), thrombocytopenia (platelet count \< 50,000 cells/mL), history of bleeding diathesis or coagulopathy. 14. Untreated clinically significant Coronary Artery Disease (CAD) requiring revascularization 15. Cardiogenic shock manifested by low cardiac output, vasopressor dependence, or mechanical hemodynamic support within the past 30 days. 16. Hemodynamic or respiratory instability requiring inotropic support, mechanical ventilation or mechanical heart assistance within 30 days of enrollment 17. Need for emergency surgery for any reason 18. Ventricular dysfunction with left ventricular ejection fraction (LVEF) \< 30% as measured by resting echocardiogram 19. Recent (within 6 months) cerebrovascular accident (CVA) or transient ischemic attack (TIA). 20. Symptomatic carotid or vertebral artery disease or successful treatment of carotid stenosis within 30 days of enrollment 21. Renal insufficiency (eGFR \< 30 ml/min per the Cockcroft-Gault formula) and/or renal replacement therapy, or end stage renal disease requiring chronic dialysis 22. GI bleeding within the past 3 months 23. Severe lung disease with Forced Expiratory Volume in 1 second (FEV1) \< 50% predicted or currently on home oxygen 24. History of cirrhosis or any active liver disease 25. Significant frailty as determined by the Heart Team (after objective assessment of frailty parameters). 26. Significant abdominal or thoracic aortic disease (such as porcelain aorta, abdominal aortic aneurysm \> 5.0 cm, severe calcification, aortic coarctation, etc.) that would preclude safe passage of the delivery system or cannulation and aortotomy for surgical AVR . 27. Severe pulmonary hypertension (e.g., pulmonary artery systolic pressure ≥ 2/3 systemic pressure) 28. A known hypersensitivity or contraindication to any of the following which cannot be adequately pre-medicated: aspirin, heparin, molybdenum, rhenium, ticlopidine and clopidogrel, contrast media 29. Ongoing sepsis, including active endocarditis 30. Body Mass Index (BMI) \> 50 kg/m2 31. Subject refuses a blood transfusion 32. Life expectancy \< 24 months due to associated non-cardiac co-morbid conditions 33. Other medical, social, or psychological conditions that in the opinion of an Investigator precludes the subject from appropriate consent 34. Severe dementia (resulting in either inability to provide informed consent for the trial/procedure, prevents independent lifestyle outside of a chronic care facility, or will fundamentally complicate rehabilitation from the procedure or compliance with follow-up visits) 35. Currently participating in an investigational drug or another investigational device trial 36. Subject is contraindicated for cardiac computed tomography (CT). 37. Subject belongs to a vulnerable population (Vulnerable subject populations are defined as individuals with mental disability, persons in nursing homes, children, impoverished persons, homeless persons, nomads, refugees, and those permanently incapable of giving informed consent. Vulnerable populations also may include members of a group with a hierarchical structure such as university students, subordinate hospital and laboratory personnel, employees of the Sponsor, members of the armed forces, and persons kept in detention).