Study is aimed to demonstrate that the self-expandable Allegra TAVI system provides lower mean gradient assessed by TTE compared to balloon-expandable valve systems in a female patient population with symptomatic severe aortic stenosis

Study is aimed to demonstrate that the self-expandable Allegra transcatheter aortic valve implantation (TAVI) system provides lower mean gradient assessed by Transthoracic Echo (TTE) at 30 days post procedure, compared to balloon-expandable valve systems in a female patient population with symptomatic severe aortic stenosis.

Patients in both arm will receive anticoagulants according to routine practice of the hospital.

Patients will be followed-up until 1 year after the procedure.

Inclusion Criteria:

1. Female sex
2. Age ≥ 75 years (according to ESC/EACTS, Guidelines for the management of valvular heart disease)
3. Severe calcific aortic valve stenosis defined as follows: high-gradient aortic stenosis (mean pressure gradient across aortic valve > 40 mmHg or peak velocity > 4.0 m/s) Symptomatic aortic valve stenosis with New York Heart Association (NYHA) Class ≥II
4. ECG-gated Multi-Slice Computed Tomographic (MSCT) measurements determined an aortic annulus perimeter-derived average diameter >19 mm and <27.4 mm or area-derived diameter >18 and <28 mm
5. Anatomy suitable for trans-femoral TAVI for both devices used in the study, including a minimum femoral diameter of 6 mm.
6. Subject with a documented local Heart Team (HT) indication for TF TAVI
7. Life expectancy longer than 1 year.
8. Willingness to undergo clinical and echocardiographic follow-up after the procedure.
9. Subject can understand the purpose of the clinical investigation, has signed voluntarily the informed consent form and is agreeing to the scheduled follow-up requirements

Exclusion Criteria:

1. Male sex
2. Non-calcific acquired aortic stenosis
3. Native unicuspid/bicuspid aortic valve or congenital aortic abnormality
4. Previous implantation of heart valve in any position
5. Severe aortic regurgitation (> 3+)
6. Severe mitral regurgitation (> 3+)
7. Severe tricuspid regurgitation (> 3+)
8. Severe left ventricular dysfunction (Left Ventricular Ejection Fraction (LVEF) < 30%)
9. Echocardiographic evidence of intracardiac mass, thrombus or vegetation
10. Untreated cardiac conduction disease in need of pacemaker implantation
11. Evidence of acute Myocardial Infarction (MI) less than 30 days before signing informed consent
12. Any need for emergency surgery
13. Any active bleeding that precludes anticoagulation
14. Liver failure (Child-C)
15. End-stage renal disease requiring chronic dialysis or creatinine clearance < 30cc/min
16. Pulmonary hypertension (systolic pressure > 80mmHg)
17. A known hypersensitivity or contraindication to all anticoagulation/antiplatelet regimens (or inability to be anticoagulated for the index procedure), to cobalt chromium, to bovine and/or collagen, glutaraldehyde or contrast media
18. Any medical, social or psychological condition that in the opinion of the investigator precludes the subject from giving appropriate consent or adherence to the required follow-up procedures
19. Currently participating in another drug or device trial (excluding observational registries) for which the primary endpoint has not been assessed
20. Subject under judicial protection, tutorship or curatorship (for France only)

Biological gender