严重二尖瓣关闭不全患者首选行体外循环下二尖瓣修补或置换手术，但创伤大、风险高。随着经导管主动脉瓣膜置换技术的成功应用，经导管二尖瓣瓣膜置换技术成为目前临床的迫切需要及研究热点，主要优势为微创、无需体外循环，尤其适用于无法耐受常规手术的危重病人。近年来国际上已有几种在研的二尖瓣瓣膜支架，经动物及少量的临床研究显示，在支架体内固定、瓣周漏、手术技术等方面仍存在障碍。本课题组在既往瓣膜支架研究的基础上，设计研制了一种采用多种方式固定、多途径防止瓣周漏及多级分段释放模式的新型二尖瓣瓣膜支架，通过初步的体内外实验表明该瓣膜支架各项性能优良。本研究拟改进和优化该新型二尖瓣瓣膜支架、输送系统及体外瓣膜支架测试系统，通过系统的体内外实验研究，优化参数选择，明确新型二尖瓣瓣膜支架体外各项性能及在大动物体内行经导管二尖瓣置换的可行性、疗效及安全性，并建立一套完善的手术技术和方法。

The principal treatment for severe mitral regurgitation (MR) is mitral valve replacement or repair under cardiopulmonary bypass,but it is judged highrisk and big traumas.Encouraged by the positive experience with transcatheter aortic valve replacement,transcatheter mitralt valve implantation(TMVI) is desired by clinical treatment.It is also the research hotspot in cardiovascular field. For minimally invasive and off pump,TMVI is suitable for high-risk or inoperable patients. A number of research groups are currently engaged in the development of TMVI. Severe technical challenges have been encountered in the application of this approach in animal and few clinical experiment, especially in effective fixing, perivalvular leakage, surgical technic and so on. Based on our previous study,we have manufactured a new-type mitral valved stent which be fixed by a variety of ways, reduced perivalvular leakage with several ways and released through multi-stage segmental model. Excellent performances of the valved stent have been showed through preliminary experiments in vivo and in vitro. In this study we aim to improve new-type mitral valved stent, delivery system and test system, to optimize parameter selection, to evaluate its performances in vitro, and its feasibility, safety and effect by implanting it in pigs.We also attempt to establish perfect surgical techniques and methods.