Early Feasibility Study for the Foldax TRIA Mitral Heart Valve Replacement

Inclusion Criteria: * Is 18 years or older * Is a candidate for mitral valve replacement with cardiopulmonary bypass * Is a candidate for mitral valve replacement due to: * Moderate to severe mitral valve stenosis, * Moderate to severe mitral valve regurgitation, or * Moderate to severe mixed mitral stenosis/regurgitation * Able to withstand short term anticoagulation * Willing and able to comply with protocol requirements Exclusion Criteria: * Prior mitral valve surgery for valve replacement or valve repair (this does NOT include percutaneous interventions i.e. Mitraclip, chordal replacement) * Requires emergency surgery * Requires other planned surgery within 12 months of valve replacement * Active endocarditis or active myocarditis * Acute preoperative neurological deficit defined as neurological deficit \< 3 months prior to enrollment * Non-cardiac illness resulting in a life expectancy of less than 12 months * Enrolled in another investigational device or drug study (enrolled patients may not enroll in other studies) * Myocardial infarction, or severe cardiac adverse event which has not returned to baseline for at least 30-days prior to enrollment * Aortic aneurysm or other medical condition that creates a higher than usual risk of surgical complications * Renal or hepatic failure * Hematological disorders, patients must not have a hematocrit of \<30%, hemoglobin \<10 g/dL, platelet count of \<100,000 cells/µL, or WBC \<4,000 cells/µL; coagulation profile must not be outside of normal limits * Patients who are prisoners or mentally ill * Patients who are pregnant or expect to become pregnant in the 12 months following implantation, or are lactating * Has a positive test result for COVID-19 virus (baseline or preoperative) * Patients who have withdrawn after implantation may not re-enter * Intraoperatively it is determined that the patient anatomy is not compatible with the device.