Development and Ex Vivo Validation of Novel Force-Sensing Neochordae for Measuring Chordae Tendineae Tension in the Mitral Valve Apparatus Using Optical Fibers With Embedded Bragg Gratings
Development and Ex Vivo Validation of Novel Force-Sensing Neochordae for Measuring Chordae Tendineae Tension in the Mitral Valve Apparatus Using Optical Fibers With Embedded Bragg Gratings
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DOI：
10.1115/1.4044142
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发表时间：
2020-01-01
影响因子：
1.7
通讯作者：
Woo, Y. Joseph
中科院分区：
文献类型：
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作者：
Paulsen, Michael J.;Bae, Jung Hwa;Woo, Y. Joseph
几乎没有技术可以提供二尖瓣装置内的力的定量数据。可以进行基于标记的应变测量，但弦几何形状和受限的光学访问是有限的。基于箔片的应变传感器已经被描述并且工作良好，但是传感器占地面积限制了可以测量的脊索的数量。取而代之的是使用光纤布拉格光栅(FBG)传感器-直径125微米的石英光纤制成的光学应变计-来克服以前测量腱索力的方法的一些局限性。利用FBG传感器，我们创造了一种力传感NeoChord(FSN)，它模仿了天然脊索的自然形状和运动。FBG传感器根据栅格的空间周期反射特定波长的光。当施加力时，栅格相对于彼此移动，从而改变反射光的波长。这种变化与所施加的力成正比。光纤光栅传感器被装在一个由0.025英寸组成的保护套中。扁平线圈，并使用聚四氟乙烯缝线连接到脊索上。在三维打印的左心模拟器上验证了力敏感新索的功能，结果表明，FBG传感器在1000赫兹的时间分辨率下提供了高度灵敏的二尖瓣索的力测量。随着脑室压力的增加，例如高血压，脊索力也会增加。总体而言，FBG传感器是一种可行、耐用和高保真的传感技术，可以有效地用于测量二尖瓣脊索力，并克服其他此类技术的一些限制。
Few technologies exist that can provide quantitative data on forces within the mitral valve apparatus. Marker-based strain measurements can be performed, but chordal geometry and restricted optical access are limitations. Foil-based strain sensors have been described and work well, but the sensor footprint limits the number of chordae that can be measured. We instead utilized fiber Bragg grating (FBG) sensors-optical strain gauges made of 125 mu m diameter silica fibers-to overcome some limitations of previous methods of measuring chordae tendineae forces. Using FBG sensors, we created a force-sensing neochord (FSN) that mimics the natural shape and movement of native chordae. FBG sensors reflect a specific wavelength of light depending on the spatial period of gratings. When force is applied, the gratings move relative to one another, shifting the wavelength of reflected light. This shift is directly proportional to force applied. The FBG sensors were housed in a protective sheath fashioned from a 0.025 in. flat coil, and attached to the chordae using polytetrafluoroethylene suture. The function of the force-sensing neochordae was validated in a three-dimensional (3D)-printed left heart simulator, which demonstrated that FBG sensors provide highly sensitive force measurements of mitral valve chordae at a temporal resolution of 1000 Hz. As ventricular pressures increased, such as in hypertension, chordae forces also increased. Overall, FBG sensors are a viable, durable, and high-fidelity sensing technology that can be effectively used to measure mitral valve chordae forces and overcome some limitations of other such technologies.