Inclusion Criteria:  Subject had a degenerated surgical aortic bioprosthetic valve with severe aortic stenosis, severe regurgitation, or a combination of at least moderate stenosis with at least moderate regurgitation per EAPCI-ESC-EACTS standardized criteria. Surgical bioprosthesis true inner diameter (true ID) was ≥ 19 mm and ≤ 27 mm and was confirmed by either CT or confirmed by the Valve in Valve Aortic App. Refer to the PCR website https://www.pcronline.com/PCR-Publications/PCR-mobile-apps/Valve-in-Valve-Aortic-app Note: if CT was contraindicated and/or not possible to be obtained, a transesophageal echocardiogram (TEE) will be accepted for sizing. Prior to Portico ViV procedure, the patient was deemed at increased risk for surgery to replace the surgical aortic bioprosthetic valve. Subject provided written informed consent prior to performing data collection for study specific visits. For patients that are deceased at the time of enrollment, all institutional/local legal and regulatory requirements for consent must be met prior to enrollment and data collection. Subject is ≥ 18 years of age or legal age in host country at the time of consent. Prior to the Portico ViV index procedure, the subject had New York Heart Association (NYHA) class II, III, or IV. Subject had a minimum vessel diameter of 6.0 mm for Portico™ delivery system access or a minimum of 5.0 mm for the FlexNav™ delivery system. Subject had the Portico or FlexNav delivery system enter their vasculature  Exclusion Criteria:  Subject had evidence of an acute MI, percutaneous intervention, or a peripheral intervention ≤30 days prior to Portico ViV index procedure (MI defined as: ST Segment Elevation as evidenced on 12 Lead ECG). Subject had uncontrolled blood dyscrasias defined as: leukopenia (WBC<3,000 mm3), acute anemia (Hb <9 g/dL), or thrombocytopenia (platelet count <50,000 cells/mm³). Subject was considered hemodynamically unstable at the time of the ViV procedure (requiring inotropic support or mechanical heart assistance) Subject had severe ventricular dysfunction with left ventricular ejection fraction (LVEF) <20% as measured by resting echocardiogram. Subject had imaging evidence of intracardiac mass, thrombus or vegetation. Subject had an active peptic ulcer or has/had upper gastrointestinal (GI) bleeding ≤3 months prior to ViV index procedure. Subject had a documented history of a cerebrovascular accident (CVA) or a transient ischemic attack (TIA) ≤6 months prior to index procedure. Subject had renal insufficiency (serum creatinine >3.0 mg/dL (265.5μmol/L)) and/or end stage renal disease requiring chronic dialysis. Subject had active bacterial endocarditis or ongoing sepsis ≤ 6 months prior to the index procedure. Surgical aortic bioprosthetic valve was unstable or rocking. Subject had a vascular condition (i.e. stenosis, tortuosity, or severe calcification) that made insertion and endovascular access to the aortic valve impossible. Subject was unable to tolerate antiplatelet or anticoagulant therapy