风湿性病变二尖瓣瓣膜的一维力学性能

Uniaxial mechanical properties of rheumatic mitral valves

目的:通过测量风湿性病变的二尖瓣膜的一维拉伸力学性能,探讨二尖瓣膜力学特性变化的原因,进而从力学角度分析风湿性瓣膜病的病理生理。方法:用软组织生物材料试验机对病变瓣膜前瓣的径向和环向分别进行一维拉伸试验,了解瓣膜的力学性能。结果:病变瓣膜前瓣存在应力滞后现象,其径向和环向特征ε分别为0.109±0.021和0.103±0.015,特征E分别为（456±11.67）×103N/m2和（418±24.59）×103N/m2,两者均无显著性差别。结论:病变瓣膜前瓣为粘弹性体,结构特性为各向同性,病变瓣膜力学性能下降是风心病病理生理改变的物理学基础。

Objective: To investigate the mechanical properties of rheumatic mitral valves. Methods: Anterior leaflets from 10 rheumatic mitral valves were mechanically tested under cyclic uniaxial stretch protocols after preconditioning. Results: The rheumatic mitral valves exhibited viscoelastic behavior.The ε of radial and circumferential direction was 0.109±0.021 and 0.103±0.015 respectively, and the E was (456 ± 11.67)×103 N/m2 and (418 ± 24.59)×103 N/m2 respectively.Conclusions: There are no differences in the extensibility between the circumferential and the radial direction ( P > 0. 05), which means that the rheumatic mitral valves are isotropic. Alteration in the mechanical properties of rheumatic mitral valves plays a very important role in the development of rheumatic heart disease.