Low–flow-mediated constriction (LFMC) has been used to assess resting endothelial function in peripheral conduit arteries. The literature describes discrepancies in the behaviour of radial versus brachial artery in response to low-flow state, the reasons for which were not addressed in a systematic and scientific way. Moreover, the influence of handedness on observed LFMC responses has not been investigated. The present study aimed at systematic measurement and comparison of the LFMC responses in radial and brachial arteries of both dominant and non-dominant arms of healthy human volunteers. We also investigated the physiological factors associated with differential LFMC response of radial versus brachial artery in the same group of subjects. Longitudinal B mode ultrasonographic cine loops of radial and brachial arteries were acquired at baseline and after producing distal circulatory arrest. Cine loops were screen grabbed and analyzed later using automated edge detection algorithms to measure end-diastolic diameters. Distal circulatory arrest was produced over the proximal forearm (for the brachial artery) and over the wrist (for the radial artery) at 250 mm Hg for 5 min after baseline measurements. Results suggested that arterial location (p = 0.0001) and baseline diameter (p < 0.0021) emerged as independent predictors of LFMC response. Differences in the LFMC responses are handedness independent and could be attributed to the arterial location along with the differences in their baseline diameters.

低流量介导的收缩 (LFMC) 已被用于评估外周导管动脉的静息内皮功能。文献描述了桡动脉与肱动脉响应低流量状态的行为差异，其原因没有以系统和科学的方式解决。此外，左手习惯对观察到的 LFMC 反应的影响尚未得到研究。本研究旨在系统测量和比较健康人类志愿者的优势和非优势臂的桡动脉和肱动脉中的 LFMC 反应。我们还研究了与同一组受试者中桡动脉与肱动脉的不同 LFMC 反应相关的生理因素。在基线和产生远端循环停止后获得桡动脉和肱动脉的纵向 B 模式超声电影循环。电影循环被屏幕抓取并随后使用自动边缘检测算法进行分析，以测量舒张末期直径。基线测量后，在前臂近端（肱动脉）和手腕（桡动脉）上以 250 mm Hg 产生远端循环停止 5 分钟。结果表明动脉位置 ( 基线测量后，在前臂近端（肱动脉）和手腕（桡动脉）上以 250 mm Hg 产生远端循环停止 5 分钟。结果表明动脉位置 ( 基线测量后，在前臂近端（肱动脉）和手腕（桡动脉）上以 250 mm Hg 产生远端循环停止 5 分钟。结果表明动脉位置 (p = 0.0001) 和基线直径 ( p < 0.0021) 成为 LFMC 反应的独立预测因子。LFMC 响应的差异与惯用手无关，可归因于动脉位置及其基线直径的差异。