Noninvasive evaluation of wall shear stress on retinal microcirculation in humans
Noninvasive evaluation of wall shear stress on retinal microcirculation in humans
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DOI：
10.1167/iovs.05-0218
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发表时间：
2006-03-01
影响因子：
4.4
通讯作者：
Yoshida, A
中科院分区：
文献类型：
--
作者：
Nagaoka, T;Yoshida, A
目的。方法应用激光多普勒测速仪(LDV)测量13例受试者视网膜一、二级支小动脉和小静脉的视网膜血管内径(D)和平均中心线血流速度(V-max、V-(Mean))。用这两个参数计算视网膜血流量(RBF)和切变率(WSR)。计算切变率下的血液粘度也用锥板粘度计测量。结果：1级动脉平均D、V-max、V-Mean、RBF、WSR平均值分别为108±13微米、41+/-10 mm/S、11+/-4亩L/分、1539+/-383 S(-1)，微静脉分别为147±13微米、23+/-3毫米/S、12+/-4亩L/分、632+/-73 S-1。在测量的切变率下，微动脉和小静脉的表观血液粘度分别为3.5+/-0.3厘泊(CP)和3.8+/-0.4厘泊(CP)。因此，小动脉的平均WSS为54+/-13达因/厘米(2)，小静脉的WSS为24+/-4达因/厘米(2)。二级小动脉的WSS明显低于一级支的WSS(P=0.002)，而一级小静脉的WSS与二级小静脉的WSS相近。结论应用激光多普勒血流速度和锥板粘度计可以无创性地评价人视网膜血管的WSS。该系统可用于进一步临床研究切应力在各种视网膜疾病发病机制中的作用。
PURPOSE. To evaluate wall shear stress (WSS) on retinal microcirculation noninvasively.METHODS. Retinal vessel diameter (D) and mean centerline blood velocity (V-max,V- (mean)) were measured in the retinal arterioles and venules at first- and second-order branches in 13 subjects using laser Doppler velocimetry (LDV). Retinal blood flow (RBF) and wall shear rate (WSR) were calculated using these two parameters. Blood viscosity at the calculated shear rate was also measured using a cone-plate viscometer. WSS was calculated as the product of the WSR and the blood viscosity.RESULTS. In the first-order branches, the averaged D, V-max,V- mean, RBF, and WSRmean were 108 +/- 13 mu m, 41 +/- 10 mm/s, 11 +/- 4 mu L/min, and 1539 +/- 383 s(-1) in the arterioles and 147 +/- 13 mu m, 23 +/- 3 mm/s, 12 +/- 4 mu L/min, and 632 +/- 73 s-1 in the venules, respectively. The apparent blood viscosities at the measured shear rates were 3.5 +/- 0.3 centipoise (cP) in the arterioles and 3.8 +/- 0.4 cP in the venules. Therefore, the averaged WSS was 54 +/- 13 dyne/cm(2) in the arterioles and 24 +/- 4 dyne/cm(2) in the venules. The WSS in the second-order arterioles was significantly lower than that in the first-order branches (P = 0.002), but the WSS in the first-order venules was similar to that in the second-order venules.CONCLUSIONS. The authors demonstrated that the WSS in the retinal vessels could be evaluated noninvasively in humans using LDV and cone-plate viscometry. This system may be useful for further clinical investigation of the role of shear stress in the pathogenesis of various retinal disorders.