Perceval S Aortic Heart Valve Study- North America

1. Subjects of age >= 18 years.
2. Subjects with aortic valve stenosis or steno-insufficiency.
3. The subject is willing to sign the informed consent.
4. The subject in which preoperative evaluation indicated the need for native or prosthetic aortic valve replacement.
5. The subject is located in a geographic location that will enable the subject to return to the study site for all follow-up examinations (i.e. geographically stable).
6. Subject will be available to the investigator(s) for postoperative follow-up beyond one year.

Exclusion criteria:

1. The subject has preexisting valve prosthesis or annuloplasty ring in the mitral, pulmonic or tricuspid position.
2. The subject requires a double or multiple valve replacement or repair of the mitral, tricuspid, or pulmonic valve.
3. The subject has a previously implanted PERCEVAL valve that requires replacement.
4. Subjects requiring simultaneous cardiac procedures, apart from septal myectomy and/or coronary by-pass.
5. The subject has active endocarditis.
6. Subjects with active myocarditis
7. The subject is or will be participating in a concomitant research study of an investigational product.
8. Subjects with aneurysmal dilation or dissection of the ascending aortic wall.
9. The subject is a minor, drug abuser, alcohol abuser, prison inmate, institutionalized, or is unable to give informed consent.
10. The subject has a major or progressive non-cardiac disease that, in the investigator's experience, results in a life expectancy of less than 1 year, or the implant of the device produces an unacceptable increased risk to the patient.
11. Subjects with known hypersensitivity to nickel alloys.
12. The subject is undergoing renal dialysis for chronic renal failure or has hyperparathyroidism.
13. The subject has had an acute preoperative neurological deficit, myocardial infarction, or cardiac event that has not returned to baseline or stabilized ≥30 days prior to the planned valve implant surgery.
14. Subject is known to be noncompliant or is unlikely to complete the study.
15. Subjects with an aortic root enlargement, where the ratio between the diameter of the sino-tubular junction and the annulus diameter, assessed by TTE, is > 1.3.