Cooper Benjamin T, Roszelle Breigh N, Long Tobias C, Deutsch Steven, Manning Keefe B
Department of Bioengineering, The Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, USA.
J Biomech Eng. 2008 Aug;130(4):041019. doi: 10.1115/1.2939342.
The mortality rate for infants awaiting a heart transplant is 40% because of the extremely limited number of donor organs. Ventricular assist devices (VADs), a common bridge-to-transplant solution in adults, are becoming a viable option for pediatric patients. A major obstacle faced by VAD designers is thromboembolism. Previous studies have shown that the interrelated flow characteristics necessary for the prevention of thrombosis in a pulsatile VAD are a strong inlet jet, a late diastolic recirculating flow, and a wall shear rate greater than 500 s(-1). Particle image velocimetry was used to compare the flow fields in the chamber of the 12 cc Penn State pediatric pulsatile VAD using two mechanical heart valves: Bjork-Shiley monostrut (BSM) tilting disk valves and CarboMedics (CM) bileaflet valves. In conjunction with the flow evaluation, wall shear data were calculated and analyzed to help quantify wall washing. The major orifice inlet jet of the device containing BSM valves was more intense, which led to better recirculation and wall washing than the three jets produced by the CM valves. Regurgitation through the CM valve served as a significant hindrance to the development of the rotational flow.
由于供体器官数量极其有限，等待心脏移植的婴儿死亡率为40%。心室辅助装置（VADs）是成人常用的移植过渡解决方案，正成为儿科患者的一个可行选择。VAD设计者面临的一个主要障碍是血栓栓塞。先前的研究表明，搏动性VAD中预防血栓形成所需的相互关联的流动特性是强烈的入口射流、舒张末期的再循环流以及大于500 s(-1)的壁面剪切率。使用粒子图像测速技术，比较了12 cc宾夕法尼亚州立大学儿科搏动性VAD腔室内使用两种机械心脏瓣膜时的流场：Bjork-Shiley单支柱（BSM）倾斜盘式瓣膜和CarboMedics（CM）双叶瓣膜。结合流动评估，计算并分析壁面剪切数据以帮助量化壁面冲洗。装有BSM瓣膜的装置BSM瓣膜的装置的主孔入口射流更强，与CM瓣膜产生的三个射流相比，导致更好的再循环和壁面冲洗。通过CM瓣膜的反流对旋转流的发展起到了显著阻碍作用。
