Lodder Joost, Verkerke Gijsbertus J, Delemarre Ben Jm, Dodou Dimitra
Department of BioMechanical Engineering, Faculty of Mechanical, Maritime and Materials Engineering, Delft University of Technology, Delft, The Netherlands Department of Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
Department of Rehabilitation Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands Department of Biomechanical Engineering, Faculty of Engineering Technology, University of Twente, Enschede, The Netherlands.
Proc Inst Mech Eng H. 2016 Feb;230(2):77-84. doi: 10.1177/0954411915621093. Epub 2015 Dec 7.
A number of studies have investigated the morphological and mechanical properties of the chordae tendineae of the mitral valve, providing comparisons between basal, marginal, and strut chordae and between chordae at the anterior and posterior leaflets. This study contributes to the literature by comparing the failure load of the chordae tendineae attached to the three posterior leaflet scallops, the anterolateral scallop (P1), middle scallop (P2), and posteromedial scallop (P3) of the mitral valve. In all, 140 chordae isolated from 23 porcine hearts were tested. First, the cross-sectional diameters of all branches in each chorda were measured using a microscope. Next, after positioning the chorda in a tensile testing machine, a preload of 0.2 N was applied, and the chordal length was measured. Cyclic loading between 0 and 0.3 N, 10 times with a speed of 1.5 mm/s, was conducted, after which the machine travelled at 1.5 mm/s until the chorda broke. We found that P2 chordae were thicker than P1 and P3 chordae and longer than P1 chordae. P2 chordae failed at significantly higher loads than P1 and P3 chordae. For all three types of chordae, almost half of the failures occurred at the chordal branch that was closest to the leaflet.
多项研究调查了二尖瓣腱索的形态和力学性能，比较了基部腱索、边缘腱索和支柱腱索之间以及前后叶腱索之间的差异。本研究通过比较附着于二尖瓣三个后叶扇贝形结构（前外侧扇贝形结构（P1）、中间扇贝形结构（P2）和后内侧扇贝形结构（P3））的腱索的破坏载荷，为该领域文献做出了贡献。总共测试了从23个猪心脏分离出的140条腱索。首先，使用显微镜测量每条腱索中所有分支的横截面积。接下来，将腱索放置在拉伸试验机中，施加0.2 N的预载荷，并测量腱索长度。以1.5 mm/s的速度在0至0.3 N之间进行10次循环加载，之后试验机以1.5 mm/s的速度运行直至腱索断裂。我们发现，P2腱索比P1和P3腱索更粗，且比P1腱索更长。P2腱索在显著高于P1和P3腱索的载荷下发生断裂。对于所有三种类型的腱索，几乎一半的断裂发生在最靠近瓣叶的腱索分支处。
