Xu Chun, Wootton David M
Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, PA 19104, USA.
Biorheology. 2004;41(2):113-25.
Platelet margination (enhanced platelet concentration in the near wall region of a blood vessel) has been well documented in small vessels. In artery-sized vessels margination has only been demonstrated in one study, using ghost cell suspensions and under relatively non-physiologic conditions of steady flow and 50 cm development length. Local sampling experiments were performed to confirm platelet margination in artery-sized stainless steel tubes, for a typical anatomical length and under pulsatile flow, using fresh EDTA-anticoagulated porcine whole blood (N=21). Experiments were designed using three-dimensional Computational Fluid Dynamics (CFD) to model the sample region with greater fidelity. Steady flow experiments in 50 cm long tubes verify published laser Doppler measurements of platelet margination in 3 mm ID tubes at normal arterial shear rate (500 s(-1). Margination persists under pulsatile flow conditions (63.8 pulses/min), but in steady flow at length of 10 cm, margination is reduced. Platelet margination ratio (the ratio of the platelet concentration near the wall to bulk average platelet count) ranges from 1.21 to 2.48. No significant effects of calculated sampling thickness (20 microm and 50 microm) or pulsatility were detected. Hematocrit margination ratio is 0.68 to 0.90. Two model platelet concentration profiles are fit to the experimental results.
血小板边缘化（血管近壁区域血小板浓度增加）在小血管中已有充分记录。在动脉大小的血管中，仅在一项研究中得到证实，该研究使用幽灵细胞悬液，且处于相对非生理的稳定血流和50厘米发展长度条件下。进行了局部采样实验，以使用新鲜的乙二胺四乙酸抗凝猪全血（N = 21），在典型解剖长度和脉动血流条件下，确认动脉大小的不锈钢管中的血小板边缘化。使用三维计算流体动力学（CFD）设计实验，以更高的保真度对样本区域进行建模。在50厘米长的管中进行的稳定血流实验验证了已发表的激光多普勒测量结果，即在正常动脉剪切速率（500 s(-1)）下3毫米内径管中的血小板边缘化。在脉动血流条件下（63.8次搏动/分钟）边缘化持续存在，但在10厘米长度的稳定血流中，边缘化减少。血小板边缘化率（壁附近血小板浓度与总体平均血小板计数之比）范围为1.21至2.48。未检测到计算采样厚度（20微米和50微米）或脉动性的显著影响。血细胞比容边缘化率为0.68至0.90。两种模型血小板浓度分布与实验结果拟合。
