Effect of Arched Leaflets and Stent Profile on the Hemodynamics of Tri-Leaflet Flexible Polymeric Heart Valves.
Effect of Arched Leaflets and Stent Profile on the Hemodynamics of Tri-Leaflet Flexible Polymeric Heart Valves.
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DOI：
10.1007/s10439-016-1674-7
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发表时间：
2017-02
影响因子：
3.8
通讯作者：
Dasi, Lakshmi P.
中科院分区：
文献类型：
--
作者：
Yousefi, Atieh;Bark, David L.;Dasi, Lakshmi P.
关键词：
聚合物心脏瓣膜（PHV）由于具有更高的耐久性以及与生物瓣膜相似的血液动力学特性，可被设计用作现有人工瓣膜的替代品。本研究的目的是评估几何形状对聚合物心脏瓣膜的贴合度和血液动力学性能的影响。所考虑的两个几何因素是支架轮廓和瓣叶拱长，它们在六种瓣膜结构中有所不同。创建了三个模型，其高径比分别为0.6、0.7和0.88。另外三个模型是通过改变拱高与支架直径之比来设计的，分别为0、0.081和0.116。对每个聚合物心脏瓣膜进行了粒子图像测速（PIV）实验，以表征速度、涡量、湍流特性、有效开口面积（EOA）和反流分数。这项研究表明，拱的存在以及较高的支架轮廓可将反流减少至5%，同时收缩期下游峰值流速降低至58%，雷诺剪切应力值降低40%。此外，在具有瓣叶拱的聚合物心脏瓣膜中观察到正向血流射流更早地重新附着。这些发现表明，尽管这两个几何因素都有助于在舒张期缩小连合间隙，但瓣叶拱会导致更大的射流开口，从而使血流更早地重新附着且能量耗散更低。
Polymeric heart valves (PHV) can be engineered to serve as alternatives for existing prosthetic valves due to higher durability and hemodynamics similar to bioprosthetic valves. The purpose of this study is to evaluate the effect of geometry on PHVs coaptation and hemodynamic performance. The two geometric factors considered are stent profile and leaflet arch length, which were varied across six valve configurations. Three models were created with height to diameter ratio of 0.6, 0.7, and 0.88. The other three models were designed by altering arch height to stent diameter ratio, to be 0, 0.081, and 0.116. Particle image velocimetry (PIV) experiments were conducted on each PHV to characterize velocity, vorticity, turbulent characteristics, effective orifice area (EOA), and regurgitant fraction. This study revealed that the presence of arches as well as higher stent profile reduced regurgitant flow down to 5%, while peak systole downstream velocity reduced to 58% and Reynolds Shear Stress values reduced 40%. Further, earlier reattachment of the forward flow jet was observed in PHVs with leaflet arches. These findings indicate that although both geometric factors help diminish the commissural gap during diastole, leaflet arches induce a larger jet opening, yielding to earlier flow reattachment and lower energy dissipation.
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影响因子：
2.4
作者：
Melling, A
通讯作者：
Melling, A
影响因子：
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作者：
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