Biomechanics and Biomaterials Design Laboratory (BBDL), School of Aerospace and Mechanical Engineering, The University of Oklahoma, 865 Asp Ave., Felgar Hall Rm. 219C, Norman, OK, 73019-3609, USA.
Department of Mechanical Engineering, Iowa State University, Ames, IA, 50011, USA.
Ann Biomed Eng. 2020 May;48(5):1463-1474. doi: 10.1007/s10439-020-02464-6. Epub 2020 Jan 31.
Proper blood flow through the atrioventricular heart valves (AHVs) relies on the holistic function of the valve and subvalvular structures, and a failure of any component can lead to life-threatening heart disease. A comprehension of the mechanical characteristics of healthy valvular components is necessary for the refinement of heart valve computational models. In previous studies, the chordae tendineae have been mechanically characterized as individual structures, usually in a clamping-based approach, which may not accurately reflect the in vivo chordal interactions with the leaflet insertion and papillary muscles. In this study, we performed uniaxial mechanical testing of strut chordae tendineae of the AHVs under a unique tine-based leaflet-chordae-papillary muscle testing to observe the chordae mechanics while preserving the subvalvular component interactions. Results of this study provided insight to the disparity of chordae tissue stress-stretch responses between the mitral valve (MV) and the tricuspid valve (TV) under their respective emulated physiological loading. Specifically, strut chordae tendineae of the MV anterior leaflet had peak stretches of 1.09-1.16, while peak stretches of 1.08-1.11 were found for the TV anterior leaflet strut chordae. Constitutive parameters were also derived for the chordae tissue specimens using an Ogden model, which is useful for AHV computational model refinement. Results of this study are beneficial to the eventual improvement of treatment methods for valvular disease.
房室心脏瓣膜（AHV）的适当血流依赖于瓣膜和瓣下结构的整体功能，任何组件的故障都可能导致危及生命的心脏病。了解健康瓣膜组件的机械特性对于改进心脏瓣膜计算模型是必要的。在以前的研究中，腱索被机械地描述为单独的结构，通常采用基于夹紧的方法，但这可能无法准确反映腱索与瓣叶插入和乳头肌之间的体内相互作用。在这项研究中，我们在独特的基于薄片的瓣叶-腱索-乳头肌测试下对 AHV 的支柱腱索进行了单轴机械测试，以观察腱索力学，同时保留瓣下组件的相互作用。这项研究的结果提供了对二尖瓣（MV）和三尖瓣（TV）在各自模拟生理负荷下腱索组织应力-应变响应差异的深入了解。具体而言，MV 前瓣的支柱腱索的峰值拉伸率为 1.09-1.16，而 TV 前瓣的支柱腱索的峰值拉伸率为 1.08-1.11。还使用 Ogden 模型为腱索组织标本推导出了本构参数，这对于 AHV 计算模型的改进很有用。这项研究的结果有助于最终改善瓣膜疾病的治疗方法。
