Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Vasc Med. 2011 Aug;16(4):267-74. doi: 10.1177/1358863X11411361. Epub 2011 Jun 27.
While adjusting flow-mediated dilation (FMD), a measure of vascular function, for shear rate may be important when evaluating endothelial-dependent vasodilation, the relationship of FMD with shear rate in study populations with cardiovascular risk factors is unclear. We aimed to investigate the association of four measures of shear rate (peak shear rate (SR(peak)) and shear rate area under the curve through 30 seconds (SR(AUC 0-30)), 60 seconds (SR(AUC 0-60)), and time to peak dilation (SR(AUC 0-ttp))) with FMD in 50 study subjects with type 2 diabetes and mild hypertension undergoing baseline FMD testing for an exercise intervention trial. Associations among measures of shear rate and FMD were evaluated using Pearson's correlations and R(2). The four measures of shear rate were highly correlated within subjects, with Pearson's correlations ranging from 0.783 (p < 0.001) to 0.972 (p < 0.001). FMD was associated with each measure of shear rate, having a correlation of 0.576 (p < 0.001) with SR(AUC 0-30), 0.529 (p < 0.001) with SR(AUC 0-60), and 0.512 (p < 0.001) with SR(peak). Nine of 50 subjects (18%) did not dilate following the shear stimulus. Among the 41 responders, FMD had a correlation of 0.517 (p < 0.001) with SR(AUC 0-ttp) and similar correlations to those found in the full sample for SR(AUC 0-30), SR(AUC 0-60), and SR(peak). In conclusion, shear rate appears to explain up to a third of between-person variability in FMD response and our results support the reporting of shear rate and FMD with and without adjustment for shear rate in similar clinical populations with CVD risk factors.
当评估内皮依赖性血管舒张时，调整血流介导的舒张（FMD）以适应切变率可能很重要，但在具有心血管危险因素的研究人群中，FMD 与切变率之间的关系尚不清楚。我们旨在研究四种切变率测量值（峰值切变率（SR(peak)）和 30 秒切变率面积（SR(AUC 0-30)）、60 秒切变率面积（SR(AUC 0-60)）和达峰时间（SR(AUC 0-ttp)））与 50 例 2 型糖尿病和轻度高血压患者的 FMD 之间的关系，这些患者正在接受运动干预试验的基线 FMD 测试。使用 Pearson 相关系数和 R(2)评估切变率测量值和 FMD 之间的相关性。四种切变率测量值在受试者内高度相关，Pearson 相关系数范围为 0.783（p<0.001）至 0.972（p<0.001）。FMD 与每种切变率测量值均相关，与 SR(AUC 0-30)相关系数为 0.576（p<0.001），与 SR(AUC 0-60)相关系数为 0.529（p<0.001），与 SR(peak)相关系数为 0.512（p<0.001）。50 例受试者中有 9 例（18%）在切变刺激后没有扩张。在 41 名应答者中，FMD 与 SR(AUC 0-ttp)的相关性为 0.517（p<0.001），与全样本中的 SR(AUC 0-30)、SR(AUC 0-60)和 SR(peak)的相关性相似。总之，切变率似乎可以解释高达三分之一的 FMD 反应个体间变异性，我们的结果支持在具有 CVD 危险因素的类似临床人群中报告切变率和 FMD，无论是否调整切变率。
