Dellimore K, Kemp I, Scheffer C, Weich H, Doubell A
Department of Mechanical and Mechatronic Engineering, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch, Western Cape, 7602, South Africa,
Australas Phys Eng Sci Med. 2013 Dec;36(4):473-86. doi: 10.1007/s13246-013-0230-0. Epub 2013 Nov 22.
Leaflet skin friction and stiffness were found to have a significant influence on the systolic performance of a 19 mm diameter bioprosthetic aortic valve based on fluid-structure interaction simulations at a heart rate of 72 bpm. Four different leaflet skin friction coefficients (0.0, 9.2 × 10(-4), 4.8 × 10(-2) and 4.8 × 10(-1)) were simulated along with three different leaflet elastic moduli (3.0 × 10(6), 3.5 × 10(6), 4.0 × 10(6) N m(-2)). Higher leaflet skin friction was found to increase the magnitude of the systolic transvalvular pressure gradient and the peak velocity through the valve, as well as decrease the valve orifice area. The results for the leaflet opening and closing kinematics also showed that higher leaflet skin friction combined with higher leaflet stiffness produces longer rapid valve opening, closing and ejection times, as well as smaller valve orifice areas. These results are consistent with clinical findings for calcified aortic valves and suggest that valve performance under stenotic conditions is strongly influenced by the combined effect of increasing leaflet stiffness and surface roughness caused by calcification.
基于心率72次/分钟时的流固耦合模拟，发现瓣叶表面摩擦力和刚度对直径19mm的生物瓣主动脉瓣的收缩期性能有显著影响。模拟了四种不同的瓣叶表面摩擦系数（0.0、9.2×10⁻⁴、4.8×10⁻²和4.8×10⁻¹）以及三种不同的瓣叶弹性模量（3.0×10⁶、3.5×10⁶、4.0×10⁶N/m²）。发现较高的瓣叶表面摩擦力会增加收缩期跨瓣压差的大小和通过瓣膜的峰值速度，同时减小瓣口面积。瓣叶开闭运动学的结果还表明，较高的瓣叶表面摩擦力与较高的瓣叶刚度相结合会产生更长的快速瓣膜开启、关闭和射血时间，以及更小的瓣口面积。这些结果与钙化主动脉瓣的临床发现一致，并表明狭窄条件下瓣膜性能受钙化导致的瓣叶刚度增加和表面粗糙度增加的综合影响很大。
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