This observational study is intended to collect real-world (post-approval use) data regarding the clinical utility and performance of the Medtronic CoreValve® System for Transcatheter Aortic Valve Implantation (TAVI).

To collect real-world (post-approval use) data regarding the clinical utility and performance of the Medtronic CoreValve® System for TAVI in patients with failing surgical aortic bioprosthesis who are at high risk for redo surgery.

Inclusion Criteria:

• Patient is > 18 years old
• Patient has a symptomatic degeneration of aortic bioprosthesis
• Acceptable candidate for elective treatment with the Medtronic CoreValveTM System (according to the most recent version of the Medtronic CoreValveTM Instructions For Use) and in conformity with the local regulatory and reimbursement context
• Logistical Euroscore > 20% or STS > 10% or presence of comorbidities responsible of contra-indication(s) for redo surgery as assessed by at least one cardiac surgeon or patients in whom heart team has assessed the redo surgery at high risk
• The patient or legal representative has been informed of the nature of the procedure and the study and has consented to participate, and has authorized the collection and release of his/her medical information by signing a consent form ("Patient Informed Consent Form")
• The patient is willing and able to comply with requirements of the study, including the 24 months follow-up
• Patient will receive the CoreValveTM device in a degenerated surgical bioprosthesis

Exclusion Criteria:

• Patients in whom anti-platelet and/or anticoagulant therapy is contraindicated
• Patient in whom heart team considers that risk of TAVI is too high with a particular attention for the risk of coronary occlusion
• Patient with prior endocarditis on failed bioprosthesis
• Patient has other medical illness associated with a limited life expectancy (i.e., less than 1 year)
• Patient with LVEF <20%, cardiogenic shock, or hemodynamic compromise requiring pressors or inotropes or mechanical support devices
• Patient with severe mitral disease associated with severe pulmonary hypertension
• Acute coronary syndrome less than 7 days before intervention
• Currently participating in another investigational drug or device study.
• Patient with significant paravalvular regurgitation
• Patient in whom internal diameter prosthesis is equal to 17 mm

Subjects will be screened from symptomatic high risk adult patients candidates for an intervention on degenerative surgical aortic bioprosthesis.