[Possibility for clinical use of mitral valve allograft: an experimental histopathological study in consideration with aortic valve allograft].

Morphologic studies were made on antibiotic preserved mitral valve allograft implanted in 8 sheep for 12 to 24 weeks. All allograft showed severe deterioration of connective tissue due to autolysis and immunological/inflammatory reactions. Compared with aortic valve allograft, mitral valve allograft failed more quickly and more severely, presumably because of differences in structure (presence of chordae tendineae and increased surface area of leaflets) and in closing pressure. The durability of cardiac valve allograft is influenced by the degree of preservation of collagen and elastic fibers in the graft. attenuation of immunologic reactions and control of fibrous sheathing.