经皮主动脉假体倾斜角度对速度和剪切应力场的影响。
Influence of the tilt angle of Percutaneous Aortic Prosthesis on Velocity and Shear Stress Fields.
作者信息
Gomes Bruno Alvares de Azevedo, Camargo Gabriel Cordeiro, Santos Jorge Roberto Lopes Dos, Azevedo Luis Fernando Alzuguir, Nieckele Ângela Ourivio, Siqueira-Filho Aristarco Gonçalves, Oliveira Glaucia Maria Moraes de
机构信息
Programa de Pós Graduação em Cardiologia - Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ - Brazil.
Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ - Brazil.
出版信息
Arq Bras Cardiol. 2017 Jul-Aug;109(3):231-240. doi: 10.5935/abc.20170115.
BACKGROUND
Due to the nature of the percutaneous prosthesis deployment process, a variation in its final position is expected. Prosthetic valve placement will define the spatial location of its effective orifice in relation to the aortic annulus. The blood flow pattern in the ascending aorta is related to the aortic remodeling process, and depends on the spatial location of the effective orifice. The hemodynamic effect of small variations in the angle of inclination of the effective orifice has not been studied in detail.
OBJECTIVE
To implement an in vitro simulation to characterize the hydrodynamic blood flow pattern associated with small variations in the effective orifice inclination.
METHODS
A three-dimensional aortic phantom was constructed, reproducing the anatomy of one patient submitted to percutaneous aortic valve implantation. Flow analysis was performed by use of the Particle Image Velocimetry technique. The flow pattern in the ascending aorta was characterized for six flow rate levels. In addition, six angles of inclination of the effective orifice were assessed.
RESULTS
The effective orifice at the -4° and -2° angles directed the main flow towards the anterior wall of the aortic model, inducing asymmetric and high shear stress in that region. However, the effective orifice at the +3° and +5° angles mimics the physiological pattern, centralizing the main flow and promoting a symmetric distribution of shear stress.
CONCLUSION
The measurements performed suggest that small changes in the angle of inclination of the percutaneous prosthesis aid in the generation of a physiological hemodynamic pattern, and can contribute to reduce aortic remodeling.
背景
由于经皮假体植入过程的性质，其最终位置会存在差异。人工瓣膜的放置将确定其有效瓣口相对于主动脉瓣环的空间位置。升主动脉中的血流模式与主动脉重塑过程相关，并取决于有效瓣口的空间位置。有效瓣口倾斜角度的微小变化对血流动力学的影响尚未得到详细研究。
目的
进行体外模拟，以表征与有效瓣口倾斜微小变化相关的流体动力学血流模式。
方法
构建一个三维主动脉模型，重现一名接受经皮主动脉瓣植入患者的解剖结构。使用粒子图像测速技术进行血流分析。针对六个流速水平对升主动脉中的血流模式进行表征。此外，评估有效瓣口的六个倾斜角度。
结果
有效瓣口处于 -4°和 -2°角度时，主流流向主动脉模型的前壁，在该区域诱导不对称且高的剪切应力。然而，有效瓣口处于 +3°和 +5°角度时，模拟了生理模式，使主流集中并促进剪切应力的对称分布。
结论
所进行的测量表明，经皮假体倾斜角度的微小变化有助于产生生理血流动力学模式，并有助于减少主动脉重塑。
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