Department of Kinesiology, Iowa State University, Ames, Iowa, United States of America.
PLoS One. 2021 Jan 7;16(1):e0244795. doi: 10.1371/journal.pone.0244795. eCollection 2021.
Impaired perfusion indices signal potential microvascular dysfunction preceding atherosclerosis and other cardiometabolic pathologies. Post-occlusive reactive hyperemia (PORH), a vasodilatory response following a mechanically induced ischemia, is a transient increase in perfusion and can assess microvascular function. The greatest blood flow change corresponding to the first minute of hyperemia (represented by time-to-peak, hyperemic velocity, AUC within 1st min) has been shown to indicate microvascular dysfunction. However, the reproducibility of these temporal kinetic indices of the PORH response is unknown. Our aim was to examine the inter- and intra-day reproducibility and standardization of reactive hyperemia, with emphasis on the kinetic indices of PORH, using laser speckle contrast imaging (LSCI) technique.
Seventeen healthy adults (age = 24 ± 3 years) completed three PORH bouts over two lab visits. LSCI region of interest was a standardized 10 cm region on the dominant ventral forearm. A 5-min brachial artery occlusion period induced by inflating an arm cuff to 200 mmHg, preceded a 4-min hyperemic period. Inter- and intra-day reliability and reproducibility of cutaneous vascular conductance (LSCI flux / mean arterial pressure) were determined using intraclass correlation (ICC) and coefficient of variation (CV%). Maximal flow and area under the curve standardized to zero perfusion showed intra- and inter-day reliability (ICC > 0.70). Time to maximal flow (TMF) was not reproducible (inter-day CV = 18%). However, alternative kinetic indices such as 1-min AUC and overshoot rate-of-change (ORC), represented as a piecewise function (at 5s, 10s, 15s, and 20s into hyperemia), were reproducible (CV< 11%). Biological zero was a reliable normalization point.
PORH measured with LSCI is a reliable assessment of microvascular function. However, TMF or its derived hyperemic velocity are not recommended for longitudinal assessment. Piecewise ORC and 1-min AUC are reliable alternatives to assess the kinetic response of PORH.
灌注指数受损表明在动脉粥样硬化和其他心血管代谢疾病之前存在潜在的微血管功能障碍。在机械诱导的缺血后发生的后阻塞性充血反应 (PORH) 是一种短暂的灌注增加，可以评估微血管功能。与充血的第一分钟相对应的最大血流变化（以达到峰值时间、充血速度、第 1 分钟内的 AUC 表示）已被证明表明微血管功能障碍。然而，PORH 反应的这些时间动力学指数的重现性尚不清楚。我们的目的是使用激光散斑对比成像 (LSCI) 技术检查 PORH 的日内和日间重现性和标准化，重点是 PORH 的动力学指数。
17 名健康成年人（年龄 = 24 ± 3 岁）在两次实验室访问中完成了三次 PORH 发作。LSCI 感兴趣区域是优势掌侧前臂上的标准化 10 cm 区域。通过将臂套充气至 200 mmHg 来引起 5 分钟的肱动脉闭塞期，随后是 4 分钟的充血期。使用组内相关系数 (ICC) 和变异系数 (CV%) 确定皮肤血管传导率 (LSCI 通量/平均动脉压) 的日内和日间可靠性和重现性。最大流量和标准化至零灌注的曲线下面积显示出日内和日间可靠性 (ICC > 0.70)。达到最大流量的时间 (TMF) 不可重现（日内 CV = 18%）。然而，替代动力学指数，如 1 分钟 AUC 和超射率变化 (ORC)，表示为分段函数（在充血的 5s、10s、15s 和 20s 时），具有重现性（CV<11%）。生物学零是可靠的归一化点。
使用 LSCI 测量的 PORH 是微血管功能的可靠评估。然而，不建议将 TMF 或其衍生的充血速度用于纵向评估。分段 ORC 和 1 分钟 AUC 是评估 PORH 动力学反应的可靠替代方法。
