Laboratory of Cardiovascular Fluid Dynamics, Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, 1455 de Maisonneuve Blvd. W, Montréal, QC, H3G 1M8, Canada.
Mechanical Engineering Department, Assiut University, Assiut, Egypt.
Cardiovasc Eng Technol. 2021 Jun;12(3):286-299. doi: 10.1007/s13239-021-00519-w. Epub 2021 Jan 19.
Aortic valve replacement remains the only viable solution for symptomatic patients with severe aortic valve stenosis. Despite their improved design and long history of successful operation, bileaflet mechanical heart valves are still associated with post-operative complications leading to valve dysfunction. Thus, the flow dynamics can be highly disturbed downstream of the dysfunctional valve.
In this in vitro study, the flow dynamics downstream of healthy and dysfunctional bileaflet mechanical heart valves have been investigated using particle image velocimetry measurements. Proper orthogonal decomposition of the velocity field has been performed in order to explore the coherent flow features in the ascending aorta in the presence of a dysfunctional bileaflet mechanical heart valve.
The ability of proper orthogonal decomposition derived metrics to differentiate between heathy and dysfunctional cases is reported. Moreover, reduced-order modeling using proper orthogonal decomposition is thoroughly investigated not only for the velocity field but also for higher order flow characteristics such as time average wall shear stress, oscillatory shear index and viscous energy dissipation.
Considering these results, proper orthogonal decomposition can provide a rapid binary classifier to evaluate if the bileaflet mechanical valve deviates from its normal operating conditions. Moreover, the study shows that the size of the reduced-order model depends on which flow parameter is required to be reconstructed.
主动脉瓣置换仍然是严重主动脉瓣狭窄有症状患者的唯一可行解决方案。尽管它们的设计得到了改进，并且已经成功操作了很长时间，但双叶机械心脏瓣膜仍然与导致瓣膜功能障碍的术后并发症相关。因此，功能失调的瓣膜下游的流动动力学可能会受到高度干扰。
在这项体外研究中，使用粒子图像测速技术测量了健康和功能失调的双叶机械心脏瓣膜下游的流动动力学。为了探索在功能失调的双叶机械心脏瓣膜存在的情况下升主动脉中的相干流动特征，对速度场进行了本征正交分解。
报告了本征正交分解衍生指标区分健康和功能失调情况的能力。此外，不仅对速度场，而且对时间平均壁切应力、振荡剪切指数和粘性能量耗散等更高阶流动特征进行了本征正交分解的降阶建模的深入研究。
考虑到这些结果，本征正交分解可以提供一个快速的二进制分类器，以评估双叶机械瓣膜是否偏离其正常运行状态。此外，该研究表明，降阶模型的大小取决于需要重建的流动参数。
