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 AorticValve Area (AVA) ≤ 1.0 cm2 or Aortic Valve Area (AVA) index ≤ 0.6 cm2/m2 and Jetvelocity ≥ 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 theHeart Team (composed of an experienced interventional cardiologist and anexperienced cardiac surgeon)

4. Eligible for transfemoral delivery of the Siegel TAVR

5. Native aortic annulus suitable for safe placement of Siegel 23mm or 26mmtranscatheter heart valve (preprocedural measurements by TransthoracicEchocardiogram (TTE) and Computed Tomography (CT) of area derived aortic annulusdiameter)

6. Understands the study requirements and the treatment procedures and provides writteninformed 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 theintroducer sheath.

3. Pre-existing prosthetic heart valve in any position (note, mitral ring is not anexclusion).

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 requiringtreatment.

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 30days 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 diathesisor coagulopathy.

14. Untreated clinically significant Coronary Artery Disease (CAD) requiringrevascularization

15. Cardiogenic shock manifested by low cardiac output, vasopressor dependence, ormechanical hemodynamic support within the past 30 days.

16. Hemodynamic or respiratory instability requiring inotropic support, mechanicalventilation 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% asmeasured 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 carotidstenosis within 30 days of enrollment

21. Renal insufficiency (eGFR < 30 ml/min per the Cockcroft-Gault formula) and/or renalreplacement 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% predictedor 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 offrailty parameters).

26. Significant abdominal or thoracic aortic disease (such as porcelain aorta, abdominalaortic aneurysm > 5.0 cm, severe calcification, aortic coarctation, etc.) that wouldpreclude safe passage of the delivery system or cannulation and aortotomy forsurgical AVR .

27. Severe pulmonary hypertension (e.g., pulmonary artery systolic pressure ≥ 2/3systemic pressure)

28. A known hypersensitivity or contraindication to any of the following which cannot beadequately pre-medicated: aspirin, heparin, molybdenum, rhenium, ticlopidine andclopidogrel, 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 anInvestigator precludes the subject from appropriate consent

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

35. Currently participating in an investigational drug or another investigational devicetrial

36. Subject is contraindicated for cardiac computed tomography (CT).

37. Subject belongs to a vulnerable population (Vulnerable subject populations aredefined as individuals with mental disability, persons in nursing homes, children,impoverished persons, homeless persons, nomads, refugees, and those permanentlyincapable of giving informed consent. Vulnerable populations also may includemembers of a group with a hierarchical structure such as university students,subordinate hospital and laboratory personnel, employees of the Sponsor, members ofthe armed forces, and persons kept in detention).