Objective To investigate the ultramicroscopic changes of cryopreserved porcine mitral valve and to explore the surgical implanting technique of this stentless mitral homograft in tricuspid position.

• 目的观察深低温保存猪二尖瓣超微结构，探索无支架二尖瓣制作方法和置换三尖瓣技术。