Porcine and Bovine Tissues
Tissue valves are made with tissues from porcine (pig) heart valves or bovine (cow) cardiac tissue because they function like human heart valves. Once the animal tissue is removed, it is chemically treated to preserve the tissue and prevent immulogic reactions once it is placed.
Homografts or Allografts
A homograft or allograft is a human valve obtained from a human donor. This type of valve is particularly beneficial for pregnant women and children because it does not require long-term anticoagulation therapy. In addition, it provides near-native hemodynamic performance. Doctors use the term "hemodynamics" to describe the flow of blood through the heart valve. Because the availability of these valves is dependent upon donors, it is often limited.
Tissue Heart Valve Advantages
The primary advantage of a tissue valve is that you do not need to be on lifelong blood-thinner medication (anticoagulation medication) unless you have another condition that makes it necessary.
Tissue heart valves from St. Jude Medical are supported by data and clinical experience. Two independent publications indicate superior durability to competitive valves out to 20 years.1,2
A valve's hemodynamic performance affects your quality of life immediately following the heart valve implant and throughout your lifetime. Tissue valves with good hemodynamic performance provide optimal blood flow and therefore allow for heart valve efficiency and activity.
Tissue Heart Valve Disadvantages
The main drawback with tissue heart valves is they are not as durable as mechanical valves. Various clinical studies indicate that tissue heart valves may last from 8 to 20 years depending on their position. Aortic valves have tended to last longer than mitral valves in these studies. The exact timing depends on the type of tissue valve, your age, lifestyle, medication requirements and other factors.