Avanzini Andrea
Department of Mechanical and Industrial Engineering, University of Brescia, Brescia, Italy.
J Biomech Eng. 2008 Jun;130(3):031015. doi: 10.1115/1.2913235.
Edge-to-edge technique is a surgical procedure for the correction of mitral valve leaflets prolapse by suturing the edge of the prolapsed leaflet to the free edge of the opposing one. Suture presence modifies valve mechanical behavior and orifice flow area in the diastolic phase, when the valve opens and blood flows into the ventricle. In the present work, in order to support identification of potentially critical conditions, a computational procedure is described to evaluate the effects of changing suture length and position in combination with valve size and shape. The procedure is based on finite element method analyses applied to a range of different mitral valves, investigating for each configuration the influence of repair on functional parameters, such as mitral valve orifice area and transvalvular pressure gradient, and on structural parameters, such as stress in the leaflets and stitch tension. This kind of prediction would ideally require a coupled fluid-structural analysis, where the interactions between blood flows and mitral apparatus deformation are simultaneously considered. In the present study, however, an alternative approach is proposed, in which results obtained by purely structural finite element analyses are elaborated and interpreted taking into account the Bernoulli type equations available in literature to describe blood flow through mitral orifice. In this way, the effects of each parameter in terms of orifice flow area, suture loads, and leaflets stresses can be expressed as functions of atrioventricular pressure gradient and then correlated to blood flow rate. Results obtained by using this procedure for different configurations are finally discussed.
缘对缘技术是一种通过将脱垂瓣叶的边缘缝合到相对瓣叶的游离边缘来纠正二尖瓣叶脱垂的外科手术。当瓣膜打开且血液流入心室时，缝线的存在会改变舒张期瓣膜的力学行为和瓣口血流面积。在本研究中，为了辅助识别潜在的关键情况，描述了一种计算方法，用于评估改变缝线长度和位置并结合瓣膜大小和形状所产生的影响。该方法基于应用于一系列不同二尖瓣的有限元方法分析，针对每种构型研究修复对功能参数（如二尖瓣口面积和跨瓣压差）以及结构参数（如瓣叶应力和缝线张力）的影响。理想情况下，这种预测需要进行流固耦合分析，同时考虑血流与二尖瓣装置变形之间的相互作用。然而，在本研究中，提出了一种替代方法，即对纯结构有限元分析获得的结果进行细化和解释，并考虑文献中可用的伯努利型方程来描述通过二尖瓣口的血流。通过这种方式，每个参数在瓣口血流面积、缝线负荷和瓣叶应力方面的影响可以表示为房室压差的函数，然后与血流速率相关联。最后讨论了使用该方法针对不同构型所获得的结果。
