valves can be clas
valves can be classified as follow :
Heart valve prostheses are of two general types mechanical and tissue ,several models of each are available .
Mechanical valves generally have three essential components that are fabricated from rigid, non physiologic biomaterials.
1-the flow occluder around both sides of which the blood must flow .
2-thecage like super structure that guides and restricts occluder motion
3-the valve body or base .
The puppet occluder moves passively responding to pressure and flow changes within the heart caged –ball, caged disk and tilting –disk mechanical valves have been used most widely .Tissue valves have a flexible trileaflet anatomy somewhat similar to that of natural valves , tissue valves have included Homografts , human cadaver valves , hetero grafts ,xeno grafts (porcine ) , aortic valves or bovine pericardial tissue or out graft fabricated for example from the patients own pulmonary valve, thigh , connective tissue or pericardium