To assess the safety and effectiveness of the SAPIEN XT transcatheter heart valve in patients with a failing surgical aortic bioprosthetic valve.

A prospective, single-arm, multicenter clinical trial. The trial will enroll patients with a failing surgical bioprosthetic valve in the aortic position demonstrating stenosis and/or insufficiency. This is a PARTNER II nested registry.

Inclusion Criteria:

1. Patient has senile degenerative aortic valve stenosis with echocardiographically derived criteria: mean gradient >40 mmHg or jet velocity greater than 4.0 m/s and an initial aortic valve area (AVA) of ≤0.8 cm2 or indexed EOA < 0.5 cm2/m2. Qualifying echo must be within 60 days of the date of the procedure.
2. Patient was symptomatic from his/her aortic valve stenosis, as demonstrated by NYHA Functional Class II or greater.
3. The heart team agreed (and verified in the case review process) that valve implantation would likely benefit the patient.
4. The study patient or the study patient's legal representative was informed of the nature of the study, agreed to its provisions and had provided written informed consent as approved by the Institutional Review Board (IRB) of the respective clinical site.
5. Heart team consensus that the risk of surgical mortality or major morbidity ≥ 50%.
6. Stenosed or insufficient surgically implanted bioprosthetic valve in the aortic position.

Exclusion Criteria:

1. Bioprosthetic valve labeled external diameter < 21mm.
2. Surgical or transcatheter valve in another position on the same side of the heart (mitral and tricuspid rings are not an exclusion).
3. Infectious endocarditis within 6 months.
4. Acute myocardial infarction ≤ 1 month (30 days) before the intended treatment.