MASA Valve Early Feasibility Study

Inclusion Criteria:

1. At least one of the following: Right Ventricular to Pulmonary Artery mean gradient > 35mm Hg, moderate or severe Pulmonary regurgitation (≥3+), or clinical indicationfor replacement of their native or prosthetic pulmonary valve with a prosthesis.

2. Age < 22 years

3. Patient is geographically stable and willing to return for 1 year follow-up for thetrial.

4. Patient's legal guardian should be willing to provide informed consent (IC) at thehospital location where they are being enrolled.

5. The patient, and the patient's parent / legal representative where appropriate, andthe treating physician agree that the subject will return for all requiredpost-procedure follow up visits and the subject will comply with clinicalinvestigation plan required follow-up visits.

Exclusion Criteria:

1. Patient is in need of or has presence of a prosthetic heart valve at any otherposition

2. Patient has a need for concomitant surgical procedures (non-cardiac)

3. Patients with previously implanted pacemaker (including defibrillators) ormechanical valves

4. Patient has an active bacterial or viral infection or requiring current antibiotictherapy (if temporary illness, patient may be a candidate 4 weeks afterdiscontinuation of antibiotics)

5. Patient has an active endocarditis

6. Leukopenia, according to local laboratory evaluation of white blood cell count

7. Acute or chronic anemia, according to local laboratory evaluation of hemoglobinPatients can be transfused to meet eligibility criteria

8. Thrombocytopenia, defined as Platelet count < 150,000/mm3 Patients can be transfusedto meet eligibility criteria

9. Severe chest wall deformity, which would preclude placement of the PV conduit

10. Known hypersensitivity to anticoagulants and antiplatelet drugs and to the devicematerials

11. Immunocompromised patient defined as: autoimmune disease, patients receivingimmunosuppressant drugs or immune stimulant drugs

12. Patient has chronic inflammatory / autoimmune disease

13. Need for emergency cardiac or vascular surgery or intervention

14. Major or progressive non-cardiac disease (liver failure, renal failure, cancer) thathas a life expectancy of less than one year

15. Currently participating, or participated within the last 30 days, in aninvestigational drug or device study

16. Alcohol or drug abuse as defined by DSM IV-TR criteria for substance abuse - thisincludes the illicit use of cannabis within the last 12 months

17. Patient has medical, social or psychosocial factors that, in the opinion of theInvestigator, could have impact on safety or compliance