TCT-322 In Vitro Optimisation of a Transcatheter Polymeric Aortic Valve
TCT-322 In Vitro Optimisation of a Transcatheter Polymeric Aortic Valve
复制标题
TCT-322 经导管聚合物主动脉瓣的体外优化
DOI：
10.1016/j.jacc.2017.09.408
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发表时间：
2017
影响因子：
24
通讯作者：
De Sciscio P
中科院分区：
文献类型：
--
作者：
De Sciscio P
背景技术尽管采用了不同的聚合物、几何形状和制造技术，但很少有聚合物瓣膜超越了临床前研究。最近，人们提出了由玻璃状和橡胶状聚合物交替嵌段组成的苯乙烯嵌段共聚物（BCP）。为了优化从BCP制作的经导管瓣膜，我们试图量化流体力学function.MethodsTranscatheter主动脉瓣（23 mm）的设计变化的影响，从3 BCP制作：聚（苯乙烯-嵌段-异丁烯-嵌段-苯乙烯）; SIBS，聚（苯乙烯-嵌段-异戊二烯-嵌段-苯乙烯）; SIS和聚（苯乙烯-嵌段-乙烯-丙烯-嵌段-苯乙烯）; SEPS。使用聚氨酯（Elast-Eon）进行比较。对五个设计参数进行了评价（支架附着、自由边缘几何形状、瓣叶厚度、模量和分子方向）在4种脉动流速下（3.9-7.1 L/min），流体动力学功能报告为有效瓣口面积（cm 2）、平均压差（mmHg），总吸收率（%）和能量损失（mJ）结果图1显示了在5.0 L/min的模拟心输出量下，每种聚合物的厚度和流体动力学函数之间的关系。瓣叶厚度与EOA（B1=-2.223，p< 0.001）和总阻力分数（B1=-24.415，p < 0.001）呈负相关，与平均压差（B1= 30.796，p < 0.001）呈正相关。采用ISO-5840最低性能要求，使用SIS、SIBS、SEPS和Elast-Eon估计的最大瓣叶厚度分别为0.38 mm、0.30 mm、0.36 mm、0.35 mm。两两比较显示，平凹型和平凸型的EOA（+13.37%，p< 0.001）、跨瓣压（-18.15%，p< 0.001）和总返流（-14.33%，p<0.46，p< 0.001）存在显著差异。平行于瓣叶基部的区域方向证明了低流速下EOA的显著改善（3.9 L/min和5.0 L/min时分别为+ 4.21%和+ 6.00%）。相反，垂直方向显示总返流和关闭瓣膜能量损失显著减少。在低流速（包括5L/min）下，材料选择不会影响给定厚度的流体动力学功能。同样，小叶-支架附着的变化也没有观察到差异。
BackgroundFew polymeric valves have advanced beyond preclinical investigation despite different polymers, geometries and manufacturing techniques being adopted. Recently, styrenic block copolymers (BCPs) consisting of alternating blocks of glassy and rubbery polymer have been proposed. In order to optimize a transcatheter valve fabricated from BCPs, we sought to quantify the effect of design change on hydrodynamic function.MethodsTranscatheter aortic valves (23mm) were fabricated from 3 BCPs: poly (styrene-block-isobutylene-block-styrene); SIBS, poly (styrene-block-isoprene-block-styrene); SIS and poly (styrene-block-ethylene-propylene-block-styrene); SEPS. A polyurethane (Elast-Eon) was used for comparison. Five design parameters were evaluated (stent attachment, free-edge geometry, leaflet thickness, modulus and molecular orientation) across 4 pulsatile flow rates (3.9-7.1 L/min), with hydrodynamic function reported as effective orifice area (cm2), mean pressure gradient (mmHg), total regurgitant fraction (%) and energy loss (mJ).ResultsFigure 1 presents the relationship between thickness and hydrodynamic function for each polymer at a simulated cardiac output of 5.0 L/min. Controlling for modulus, leaflet thickness was inversely correlated with EOA (B1=-2.223, p< 0.001) and total regurgitant fraction (B1=-24.415,< 0.001), and positively correlated with mean pressure gradient (B1= 30.796,< 0.001). Adopting the ISO-5840 minimum performance requirements, the estimated maximum leaflet thickness using SIS, SIBS, SEPS and Elast-Eon was 0.38 mm, 0.30 mm, 0.36 mm, 0.35 mm, respectively. Pairwise comparison revealed a significant difference between a plano-concave and plano-convex profile for EOA (+ 13.37%, p< 0.001), transvalvular pressure (-18.15%, p< 0.001) and total regurgitation (-14.33%±0.46, p< 0.001). Domain orientation parallel to the leaflet base demonstrated a significant improvement in EOA at low flow rates (+ 4.21% and+ 6.00% at 3.9 L/min and 5.0 L/min, respectively). Conversely, perpendicular orientation demonstrated a significant reduction in total regurgitation and closed valve energy loss. At low flow rates, including 5L/min, material selection did not effect hydrodynamic function for a given thickness. Likewise, no difference was observed with a change in leaflet-stent attachment.