The ASCEND post-market clinical follow-up study is undertaken to evaluate safety and clinical performance of the On-X Ascending Aortic Prosthesis (AAP) used in surgical aortic valve replacement.

In this study patients will be observed that receive an On-X AAP implant for the treatment of a diseased, damaged, or malfunctioning native or prosthetic heart valve. The On-X AAP will be implanted at the discretion of the treating physician. Participating physicians will be asked to provide their observations collected during routine care for patients he/she had decided to treat with the On-X AAP. Written informed consent, specifically allowing the use of clinical records for this observational study, will be obtained from every patient in Europe and every patient that is alive in the US prior to data collection where required. In Europe, every patient will be enrolled prospectively prior to the intervention.

In the US, patients can be enrolled retrospectively after the intervention or prospectively prior to the intervention. The data from patients who have died following their implant will be recorded in the database without the requirement for written informed consent after IRB approval.

The period of data collection will be approximately 60 + 6 months (depending on the date of the last follow-up visit) from the surgery for each patient.

Echocardiography images at prior to discharge, at 12 months, 60 months will be evaluated by a CoreLab. All adverse events defined in the Clinical Event Committee (CEC) charter will be adjudicated by the CEC.

Inclusion Criteria:

• Patient ≥ 18 years of age at time of On-X AAP implant

• Patient understands and has signed the Informed Consent Form:

  • Prior to implant of On-X AAP or
  • Post implant (US only) or
  • Patient died prior to enrollment (US only)

• Patient is willing and able to participate in follow-up

Exclusion Criteria:

• Patient unable to tolerate anticoagulation therapy
• Patient with active endocarditis at the time of his / her On-X AAP implant
• Patient participates / participated in another clinical investigation which may interfere / may have interfered with the effectiveness of anticoagulation therapy
• Patient has anomalous anatomy or medical, surgical, psychological or social history or conditions that, in the investigator's opinion, could limit the subject's ability to participate in the clinical investigation or to comply with follow-up requirements of the clinical investigation results
• Patients in which On-X AAP is implanted in combination with AMDS or FET
• Patient's life expectancy is less than 3 years in the opinion of the Investigator

Male and female patients (≥ 18 years of age) who either underwent (US only) or will be undergoing (Europe and US) implant of the On-X AAP for aortic valve and ascending aorta replacement and who meet the criteria listed below.