Coronary Flow Impacts Aortic Leaflet Mechanics and Aortic Sinus Hemodynamics
Coronary Flow Impacts Aortic Leaflet Mechanics and Aortic Sinus Hemodynamics
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DOI：
10.1007/s10439-015-1260-4
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发表时间：
2015-09-01
影响因子：
3.8
通讯作者：
Dasi, Lakshmi Prasad
中科院分区：
文献类型：
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作者：
Moore, Brandon L.;Dasi, Lakshmi Prasad
主动脉瓣瓣叶上的机械应力是引发导致钙化性主动脉瓣疾病的过程的众所周知的介质。鉴于非冠状动脉瓣叶首先钙化，可以假设源自口的冠状动脉血流显著影响主动脉瓣叶力学和窦血流动力学。高分辨率时间分辨粒子图像测速（PIV）测量进行映射的时空特征的主动脉窦血流和瓣叶运动，有和没有生理冠状动脉血流在一个良好的控制在体外设置。体外设置包括安装在生理主动脉窦腔中的猪主动脉瓣，其具有动态控制的冠状动脉阻力以模拟生理冠状动脉血流。结果进行了分析，使用定性条纹图说明血流模式的时空复杂性，定量速度矢量和剪切应力等值线图显示冠状窦和非冠状窦之间的机械环境的差异。结果表明，冠状动脉血流的存在将经典的窦涡拉入窦内更深，并增加了瓣叶基部附近的流速。这在非冠状窦中未观察到的瓣叶附近产生了有益的剪切应力和冲洗增加。此外，瓣叶向窦内进一步打开约10%，冠状动脉血流情况表明上级瓣膜开口面积。冠状动脉血流的存在显著改善了瓣叶力学和窦血流动力学，其方式将降低低壁剪切应力条件，同时改善瓣叶基部的冲洗。
Mechanical stresses on aortic valve leaflets are well-known mediators for initiating processes leading to calcific aortic valve disease. Given that non-coronary leaflets calcify first, it may be hypothesized that coronary flow originating from the ostia significantly influences aortic leaflet mechanics and sinus hemodynamics. High resolution time-resolved particle image velocimetry (PIV) measurements were conducted to map the spatiotemporal characteristics of aortic sinus blood flow and leaflet motion with and without physiological coronary flow in a well-controlled in vitro setup. The in vitro setup consists of a porcine aortic valve mounted in a physiological aorta sinus chamber with dynamically controlled coronary resistance to emulate physiological coronary flow. Results were analyzed using qualitative streak plots illustrating the spatiotemporal complexity of blood flow patterns, and quantitative velocity vector and shear stress contour plots to show differences in the mechanical environments between the coronary and non-coronary sinuses. It is shown that the presence of coronary flow pulls the classical sinus vorticity deeper into the sinus and increases flow velocity near the leaflet base. This creates a beneficial increase in shear stress and washout near the leaflet that is not seen in the non-coronary sinus. Further, leaflet opens approximately 10% farther into the sinus with coronary flow case indicating superior valve opening area. The presence of coronary flow significantly improves leaflet mechanics and sinus hemodynamics in a manner that would reduce low wall shear stress conditions while improving washout at the base of the leaflet.