笔者想感谢谁参加了我们的研究中，我们已经评估使用FMD测试内皮功能的众多学科和病人。

注:以下FMD过程中中西医血管和运动生理学（LIVEP）的血管实验室评估研究常规进行。所有的程序遵循赫尔辛基宣言的原则和乔治亚大学校务由机构审查委员会的批准。所有的参与者被告知的目标和获得参与该技术可能的风险的书面同意之前， 图1说明了应考虑肱动脉口蹄疫超声评估的基本要素的概要总结。 1.除准备（在抵达前） <ol><li>确认参与者从实践锻炼（≥12小时），咖啡因（≥12小时），吸烟或二手烟暴露（≥12小时），补充维生素（&gt; 72小时）和任何药物（≥4小时半衰期弃权药，为1大的非甾体抗炎剂y和3天阿司匹林）。 </li><li>确保参与者空腹条件下或只在测试消耗低脂肪膳食4之前。 </li><li>当测试绝经前妇女，因此建议在月经周期的月经期来进行口蹄疫协议来限制内源性雌激素和孕酮8,32,33的影响。 </li></ol> 2.除准备（抵达时） <ol><li>测量收购前，验证对象是在仰卧位休息在一个安静，温度控制（22°C至24°C）的房间约20分钟，使血流动力学稳定状态。 </li><li>在标准肢体附加3导联心电图导致II位置。使用美国标准仪器，将白/负极铅只是右肩锁骨下方。黑/双极性导线连接附近的肩膀锁骨左侧下方，连接红色/正极引线下面在胸部的横向基部左侧胸肌。 </li><li>延长受试者的臂横向在约80℃肩外展的并固定前臂远端在真空包装枕头的测定（ 图2）期间保持臂的精确位置。 </li><li>放置前臂箍立即远端肱骨内上髁，并确保没有正在触摸的压脉袋，包括下表（ 图2）。 </li></ol> 3.测量基线<ol><li>映射肱动脉的超声: <ol><li>同时用手握住探头，横截面的位置，并开始扫描上臂的内侧开始在二头肌的插入和近侧进行。 </li><li>内B模式（灰度），确定肱动脉和侧支血管，并使用彩色流量（CF）方式，以帮助确认动脉的位置。解释颜色和搏动仔细考虑换能器的方向，以确保动脉，而不是静脉评估。 注意:对于面向头探头指示灯，红色意味着流向换能器（动脉血流），而蓝色表示流走（静脉血流）。 </li></ol></li><li>肱动脉鉴别: <ol><li>发现肱动脉后，旋转探头90°纵向扫描臂。获得2至10厘米肘窝上面之间的图像。 </li><li>确定解剖标志，如静脉和在同一主题的多个评估筋膜（ 图3）。 </li></ol></li><li>固定探头: <ol><li>固定探头的立体探头支架。确认探针被适当地固定，以避免过度的运动。与固定在支架上的探头，确保图像是作为手动得到无支架的图像一样好。 </li></ol></li><li>优化Resolutio图像的N: <ol><li>与固定探头优化使用时间增益控制图像（TGC的）。 注:获得从腔和血管壁之间的前部和后部内膜接口清亮的B模式图像时，一个最佳的图像实现。 </li><li>有技术人员手动调节增益，联络点，动态范围，和谐波，以获得内皮的远近壁的清晰定义的图像。 </li></ol></li><li>多普勒模式: <ol><li>继B-模式采集，进行双工在脉冲多普勒模式扫描。 </li><li>使用脚跟由摇摆传感器上的一端比其它调节肱动脉图像，将获得的60°声波作用的角度与支架内的探针趾方法。 </li></ol></li><li>基线采集: <ol><li>获取标识与该动脉的内膜清晰内膜壁内皮层的满意的B模式图像。 ENS该多普勒信号出现锐利和清晰的声音，没有围巾URE。 </li><li>通过冻结和解冻图像重置超声波电影圈。按F1键开始在图像处理软件记录数据。为至少30秒记录的基准数据。分析平均直径和血流速度为30秒，以表示基线值。注:不同的超声波及软件调校可能需要不同的顺序，以获得所需的操作。 </li></ol></li></ol> 4.血管闭塞测量<ol><li>前臂闭塞: <ol><li>迅速膨胀前臂闭塞袖口，使用压缩空气，至超收缩压（250毫米汞柱）5分钟以诱导动脉闭塞。 </li><li> 4分钟和前臂闭塞30秒后，开始采集数据。 注:闭塞测量将通过闭塞的最后30秒来表示。 </li></ol></li></ol> 5.反应性充血（邮政袖口释放）测量<ol&gt; <li>继续从预发布袖口数据采集: <ol><li>袖带放气5分钟。 </li><li>保持以下袖带释放记录两分钟。 </li></ol></li><li>下面的帖子发布袖口录制2分钟，停止并保存录音。最高5秒平均在整个2分钟闭塞后收集期间的时间间隔将被用来代表峰充血直径。 </li></ol> 6.结果分析:边缘检测和跟踪墙<ol><li>由于口蹄疫分析的复杂性，根据制造商的说明使用的边缘检测和壁跟踪软件整个口蹄疫测试更高的再现性。 注意:此离线分析是操作者较少地依赖比手动评估，因此提高了口蹄疫数据4,34-36的准确性。此外，这种离线分析系统也允许与ECG终了舒张动脉的识别同步直径，避免了4个直径的脉冲相关的变化失真。应当指出的是，虽然使用心电图被认可，以减少脉动变化，它也可以没有心电图gaiting 37执行口蹄疫协议。虽然不建议，如果边缘计算机辅助分析是不可用的，直径和速度的仔细的手工评估应收集36。 </li><li>对于血管直径的评价，这是必要的目视检查每个帧确定沿B模式图像38超声波卡钳的最佳位置。 注意:不管数据分析方法的，建议的第20秒反应性充血和每5秒对剩余阻塞后周期4期间，收集直径和速度数据每4秒。 </li></ol>

作者什么都没有透露。

在1989年20引入，口蹄疫测试已被广泛用于在人中作为内皮功能的非侵入性的措施。口蹄疫不仅被证明是预测未来的血管相关疾病的风险19,52,53，降低FMD值已经显示与心血管损伤24,25,54强烈相关。虽然也有其他的技术来评估血管内皮功能，既侵入（冠状动脉造影）和非侵入性（静脉体积描记术和手指体积描记法），口蹄疫一直是最广泛使用的，由于它的非侵入性和外周动脉功能23的快速评估。 口蹄疫试验采用了短暂的前臂闭塞诱导反应性充血及随后的剪应力2,4。此增强的在从内皮衍生NO合成酶31,55 NO产生的局部增加剪应力的结果，即通过血管壁扩散从而我nducing平滑肌松弛和随后，血管扩张31。人们普遍认为5分钟闭塞周期被主要是由NO介导的，而闭塞的较长时间后的血流量的增加可能涉及比NO 56其他缺血诱导的血管扩张剂。 口蹄疫评估方法问题肱动脉FMD试验的非侵入性增加了在该技术的兴趣。不过，值得注意的是，有一些影响这个过程的生理和技术稳定性实际挑战和方法上的考虑，限制了它的临床应用57。具体来说，进行口蹄疫测试需要大量的初始投资购买必要设备（ 如超声，快速充气袖口和分析软件）。此外，高技能和训练有素的人/超声检查能理解生理学口蹄疫检验术是需要进行口蹄疫测试。在方法论上，它认为有口蹄疫测试没有任何标准化许多不同的方式方法是非常重要的。因此，规范数据是从实验室到实验室使得难以确定在内皮功能"真"的异常不同。此外，许多干扰因素可影响口蹄疫测试，并因此人的基础状态的全面理解被测试是必要的，以排除假负值。然而，符合更新的口蹄疫测试建议高精度的技术的和减少口蹄疫变异可以实现。 超声波技术最新的超声技术是必不可少的。使用同步采集B型直径和脉搏波多普勒速度的被推荐为直径的更严格的检测改变4和剪切率的精确计算。由于缺乏双工模式的技术可以做一些这5之后说明血管扩张程度相似的结果和一个10分钟的接合期间8,58,59挂钩，而最近研究使用双工模式所描述的缺血长时间如何以更大的再灌注33,60有关。 此外，为了改善口蹄疫试验的精确度，它实现了多普勒束和动脉的取向之间声波作用的适当的角度是重要的。它建议以获得≤60°的声波作用角度达到足够的图象质量的平衡，并降低速度误差4,36的水平。这也是值得注意的是，至少10 MHz的线阵探头，与使用立体定向钳61,62的，建议获得高品质的B型图像4。 袖口位置袖带的位置已被详细研究在许多不同的研究，因为它的尺寸和它的位置可不仅有助于在剪切应力刺激的变化8,63,64，还可能影响有助于口蹄疫机制响应41， 63,65。建议放在前臂闭塞箍，远端的超声探头，以诱导内皮依赖性血管舒张36。 分析为了实现精确的口蹄疫，与边缘检测算法的自动软件分析系统，强烈推荐4。边缘检测依赖于一个精确的基准直径，这是至关重要的确定和用于有效口蹄疫的计算的基础。至少需要10个心动周期（或30秒）的平均来表示基线直径，而直径峰值响应应使用5秒平均4来计算。

心血管疾病是全世界发病率和死亡率的首要原因。血管内皮功能障碍表示朝向多种血管相关疾病的发展1的初始阶段。因此，血管内皮功能的人类的准确评估是一个重要的技术，可以帮助理解多种心血管病症的病因，以改善治疗和预防疾病的疗效的最终目标。 内皮内皮是细胞单层该合成众多血管活性物质，诸如一氧化氮（NO），前列环素，内皮素，内皮细胞生长因子，白细胞介素，和纤溶酶原抑制剂2。这些因素有助于内皮的功能来调节血液的流动性，血管张力，血小板聚集，血浆成分和血管壁INFL的渗透性ammation 2-4。此外，没有在促进血管扩张和维持内皮完整性的关键抗动脉粥样硬化的作用。通过控制输送氧气到组织和它们的代谢需求3,5-之间的平衡NO调节血管张力和直径。有多个内源性，外源性，和机械刺激因子诱导内皮NO合酶（eNOS），它从NO合成的L-精氨酸6,7。最显着的机械刺激是剪切应力。壁剪切应力与eNOS更大激活，导致NO的产生和随后的平滑肌松弛4。出于这个原因中的NO生物利用度的减少通常被用作内皮功能障碍8的量度。 内皮功能障碍血管扩张和血管收缩因子之间的失衡导致内皮机能障碍2。此外，relea炎症介质和改变的局部剪切力本身可以提高内皮衍生的活性氧（ROS）的合成。这种上调在氧化还原不仅信令 ​​修改内皮的完整性，并降低NO 9的合成，它可以脱开的eNOS导致直接生产的额外自由基。最终，这改善中的NO生物利用度促进血管收缩，血管硬度，降低动脉扩张4。 内皮功能障碍的程度已与若干疾病，如其中包括高血压10，动脉粥样硬化11，缺血性中风12，糖尿病13，先兆子痫14或肾脏疾病15的严重程度有关。因此，有广阔的兴趣，不仅评估随时间的血管内皮功能的变化，也下列的治疗性干预。不同的方法已被用于在冠状动脉和外周环流19内皮功能都侵入（心导管和静脉闭塞容积描记3,16）和非侵入性（流动介导的扩张，桡动脉张力计和脉冲轮廓分析4,17,18）的临床评估。 血流介导的舒张流动介导的舒张（FMD）是血管内皮功能的非侵入性的，超声评价，并已与血管的健康问题的发展密切相关。公司自1989年成立以来20，口蹄疫已被广泛用作可靠， 体内方法评估人类19,21,22主要是NO介导的血管内皮功能。事实上，肱动脉FMD试验已经与其他微创技术23和众多调查相关的所描述的口蹄疫和心血管损伤24,25这样INDIVI之间存在很强的负相关关系偶与更多的血管病变具有更低的FMD 25。因此，这些数据强调的预后信息，这种技术可提供，因为它涉及到未来心血管疾病中的无症状受试者26-30。 在口蹄疫检测，肱动脉的直径在基线和前臂的停循环上映后连续测量。在袖口发布，诱导反应性充血促进介导的NO释放和后续血管舒张19,31在剪切应力的增加。口蹄疫被表示为压脉袋的释放在基线直径（FMD％）相比，按照动脉直径增加的百分比。 尽管在此技术的日益临床利益，口蹄疫测试是一种生理评估，因此，几个变量需要，以便在人体中进行的血管内皮功能的精确评估被考虑。这是rticle描述的标准化协议和推荐的方法来最小化的技术和生物问题，以帮助改善口蹄疫测试的准确性，再现性和解释。

<table><tbody><tr><td>Doppler ultrasound</td><td>GE Medical Systems&amp;nbsp;</td><td>Logiq 7</td><td>Essential to include Duplex mode for simultaneous acquisition of B-mode and Doppler</td></tr><tr><td>Electrocardiographic (ECG) gating&amp;nbsp;</td><td>Accusync Medical Research</td><td>Accusync 72</td><td></td></tr><tr><td>12-MHz Linear array transducer&amp;nbsp;</td><td>GE Medical Systems</td><td>11L-D</td><td>A high-resolution linear array probe is essential</td></tr><tr><td>Forearm occlusion cuff&amp;nbsp;</td><td>D.E. Hokanson</td><td>SC5</td><td>5 cm x 84 cm</td></tr><tr><td>Ultrasound transmission gel&amp;nbsp;</td><td>Parker</td><td>01-08</td><td></td></tr><tr><td>Rapid cuff inflator</td><td>D.E. Hokanson</td><td>E-20 AG101</td><td></td></tr><tr><td>Sterotactic-probe holder</td><td>Flexabar&amp;nbsp;</td><td>18047</td><td>Magnetic base fine adjustor</td></tr><tr><td>Edge detection analysis software</td><td>Medical Imaging Applications</td><td>Brachial Analyzer 5</td><td></td></tr></tbody></table>

ultrasound assessment of endothelial function: a technical guideline of the flow-mediated dilation test

心血管疾病是死亡的主要原因和残疾的主要病因全世界。血管内皮功能障碍是一种病理状况，其特征主要由中断在血管舒张和血管收缩的物质之间的平衡，并提出在动脉粥样硬化的心血管疾病的发展中发挥重要的作用。因此，血管内皮功能在人类一个准确的评估，是一个重要的工具，可以帮助人们更好地理解多心为中心的病症的病因。 在过去的25年里，许多方式方法已被开发，以提供内皮功能的评估在人中。在1989年推出的口蹄疫测试采用了前臂闭塞和随后的反应性充血，促进一氧化氮的产生和肱动脉血管舒张。现在口蹄疫测试是使用最广泛的，非侵入性，ULTR在人类和内皮功能asonic评估已经与未来心血管事件相关联。 虽然口蹄疫测试可能有临床应用，它是继承了需要考虑的几个混杂因素生理评估。本文介绍了确定口蹄疫包括推荐的方法，以帮助减少生理和技术问题，提高了评价的精度和可重复性的标准化协议。

从明显健康的队列组的基线特征在表1中呈现在综合血管和运动生理学（LIVEP）的实验室进行的口蹄疫测试的最常见的变量在表2中，以下的变量被认为是主要的口蹄疫参数在公布的FMD教程4和准则36分析。 基线和峰值直径下列适当的驯化阶段，与血液的速度至少为10心动周期在10至30秒39的时间段的平均应用于表示基准直径。此外，峰直径，以下袖带释放的最大扩张，应计算基于最高5秒平均在两分钟后闭塞收藏品ñ期4。 口蹄疫响应口蹄疫响应由肱动脉内径相对于处于静止测量基线肱动脉内径前臂袖口释放后的最大变化表示。因此，口蹄疫响应的确定是根据下列公式计算: <img alt="式（1）" src="/files/ftp_upload/54011/54011eq1.jpg" />口蹄疫响应的幅度成正比的剪切应力和严重依赖内皮完整性，血液粘度和血液速度36,40。它已经观察到的最大口蹄疫是达到超过之间45到90秒的时间窗口，虽然峰血管扩张本身可继续到180秒后袖带放气41。 剪切应力已被描述为通过血液中的内膜表面上施加的平行，摩擦力和作为用于口蹄疫的主要刺激反应42。剪应力可以计算如由血管直径除以速度和粘度的产物。但是，剪切应力的一个更简单的指数是剪切速率，它是由血流速度和肱动脉直径下面的公式的同时测量计算: <img alt="公式（2）" src="/files/ftp_upload/54011/54011eq2.jpg" />此外，累积剪切速率（曲线的AUC下面积;秒-1）具有也可考虑，因为它反映了峰值剪切和峰直径8之间的延迟。它是基于不规则四边形规则计算，以下每4秒的第一个20秒袖带释放，而对于其余的数据收集期间的，每5秒43。 口蹄疫正常化（FMD /剪切） 给出记反应性充血响应的从属间变性剪切应力和口蹄疫，和保持之间的依赖，已经建议正常化与剪应力44,45口蹄疫响应。虽然通过剪切速率除以口蹄疫如何正确口蹄疫正常化剪切，没有达成共识控制的口蹄疫响应不同剪切轮廓的影响，提供了额外的洞察肱动脉血管舒张功能39,46的激励/响应机制。然而，应该指出的是，有一个上升的认识和临时接受这一归一化方法，因为它仅在一定的条件下36有效。另一个建议方法正常化口蹄疫和改进了测试的灵敏度和可靠性是表示该数据作为一个剂量-响应曲线，其中剪切涉及动脉扩张47的幅度。此外，使用异速生长缩放正常化口蹄疫和用于冲击基线直径可能对口蹄疫响应控制已经提出48。 时间 - 峰值血管舒张由于在之间不同人群中描述的口蹄疫的时间过程的不同的反应，当确定分析口蹄疫已成为重要49,50的时间-峰值（TTP）血管舒张。然而，应该指出的是，TTP是部分否独立的，并且可能不是适当的参数FMD被单独用来代表内皮健康51。 图4示出在具有代表性的个体的口蹄疫测试的直径和速度响应。 Reacti已经充血引起的峰值速度其中，在短暂的延迟后，其次是在直径增大。 <img alt="图1" src="/files/ftp_upload/54011/54011fig1.jpg" /> 图1:在标准化的程序进行肱动脉FMD测试的插图有关的准确和可靠的口蹄疫测试，必须有适当的超声设备以及之前执行的技术中主体的充分的准备。一旦参与者处于休息状态，可以执行基准数据采集。闭塞的五分钟后，袖带释放创建引起对内皮剪切应力的反应性充血反应。最后，建议使用边缘检测和墙壁跟踪软件分析的结果。 <a href="https://www.jove.com/files/ftp_upload/54011/54011fig1large.jpg" target="_blank">请点击此处查看该F的放大版本</a>igure。 <img alt="图2" src="/files/ftp_upload/54011/54011fig2.jpg" width="700" /> 图 2: 对肱动脉FMD测试制得的受试者的表示拍摄对象的臂横向延伸并固定在一真空包装的枕头。前臂袖带放置立即远端肱骨内上髁。超声换能器被固定在保持器和放置在二头肌获得肱动脉的数据的插入的上方。 <img alt="图3" src="/files/ftp_upload/54011/54011fig3.jpg" /> 图3:为在同一受试者重复评估解剖标志的鉴定图2A，2B，2C和2D示出了在同一个体肱动脉上四个不同天的基线评估。箭头标识用于图像的解剖标志每个单独的一天动脉。 <a href="https://www.jove.com/files/ftp_upload/54011/54011fig3large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <img alt="图4" src="/files/ftp_upload/54011/54011fig4.jpg" /> 图4:是口蹄疫试验中观察到的典型的速度和直径响应的个体的代表性图说明30秒，血管闭塞的最后30秒（OCC），和反应性充血响应的初始基线（BL）期间（120秒）以下的前臂袖口释放。实线表示直径响应和虚线代表整个FMD技术的血流速度。 <a href="https://www.jove.com/files/ftp_upload/54011/54011fig4large.jpg" target="_blank">请点击此处查看该图的放大版本。</a> <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-p年龄="总是"&gt; <tbody><tr><td> 变量 </td><td></td></tr><tr><td> ñ </td><td> 62 </td></tr><tr><td> 男/女 </td><td> 31分之31 </td></tr><tr><td> 年龄 （岁） </td><td> 32±2 </td></tr><tr><td> 高度 （cm） </td><td> 167±2 </td></tr><tr><td> 重量 （kg） </td><td> 66.1±2.2 </td></tr><tr><td> BMI（公斤/米2） </td><td> 22.8±0.7 </td></tr><tr><td> 收缩压 （毫米汞柱） </td><td> 115±2 </td></tr><tr><td> 舒张压 （毫米汞柱） </td><td> 68±1 </td></tr><tr><td> FEV 1预测 （％） </td><td> 101.2±1.8 </td></tr><tr><td> 葡萄糖 （毫克/分升） </td><td> 88±1 </td></tr><tr><td> 总胆固醇 （毫克/分升） </td><td> 162±5 </td> &lt;/ TR&gt; <tr><td> 高密度脂蛋白胆固醇 （毫克/分升） </td><td> 57±2 </td></tr><tr><td> 低密度脂蛋白胆固醇 （毫克/分升） </td><td> 93±5 </td></tr><tr><td> 甘油三酯 （毫克/分升） </td><td> 77±5 </td></tr><tr><td> 血红蛋白 （克/分升） </td><td> 14.7±0.3 </td></tr><tr><td> 血细胞比容 （％） </td><td> 43.4±0.7 </td></tr></tbody></table> 表1:特性和健康的主题队列数据的血液化学表示为平均值±SEM。身体质量指数（BMI），收缩压（SBP），舒张压（DBP），用力呼气容积一秒钟（FEV 1），高密度脂蛋白（HDL），低密度脂蛋白（LDL）。 <table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always"><tbody><tr><td> 瓦尔iable </td><td> N = 62 </td></tr><tr><td> 基线直径 （厘米） </td><td> 0.322±0.009 </td></tr><tr><td> 峰直径 （厘米） </td><td> 0.343±0.009 </td></tr><tr><td> 口蹄疫 （％） </td><td> 6.7±0.4 </td></tr><tr><td> FMD绝对变化 （厘米） </td><td> 0.021±0.001 </td></tr><tr><td> 剪切速率 （秒-1，AUC）的</td><td> 46607±2940 </td></tr><tr><td> 口蹄疫/剪切 （％/秒-1 AUC） </td><td> 0.16±0.01 </td></tr><tr><td> 时间-峰值血管舒张 （秒） </td><td> 44±2 </td></tr></tbody></table> 表2:来自显然健康的队列数据肱动脉FMD变量表示为平均值±SEM表示。

Watch this Scientific Journal Video about Ultrasound Assessment of Endothelial Function: A Technical Guideline of the Flow-mediated Dilation Test at JoVE.com

Ultrasound Assessment of Endothelial Function: A Technical Guideline of the Flow-mediated Dilation Test

血管内皮功能的超声评估:血流介导的舒张试验的技术指导原则

The flow mediated dilation (FMD) test is the most commonly utilized, non-invasive, ultrasound assessment of endothelial function in humans. Although the FMD test has been related with the prediction of future cardiovascular disease and events, it is a physiological assessment with many inherent confounding factors that need to be considered.

Cardiovascular disease is the primary cause of mortality and a major cause of disability worldwide. The dysfunction of the vascular endothelium is a ...

ultrasound-assessment-endothelial-function-technical-guideline-flow

Nanyang Technological University

Research

JoVE Journal

Medicine

17.4K 次观看.  Georgia Regents University. The flow mediated dilation (FMD) test is the most commonly utilized, non-invasive, ultrasound assessment of endothelial function in humans. Although the FMD test has been related with the prediction of future cardiovascular disease and events, it is a physiological assessment with many inherent confounding factors that need to be considered. 

视频: Ultrasound Assessment of Endothelial Function: A Technical Guideline of the Flow-mediated Dilation Test

Assessing Endothelial Vasodilator Function with the Endo-PAT 2000

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of the panoply of paracrine factors that it secretes, the endothelium regulates the contractile and proliferative state of the underlying vascular smooth muscle, as well as the interaction of the vessel wall with circulating blood elements. Because of its central role in mediating vessel tone and growth, its position as gateway to circulating immune cells, and its local regulation of hemostasis and coagulation, the the properly functioning endothelium is the key to cardiovascular health. Conversely, the earliest disorder in most vascular diseases is endothelial dysfunction.
In the arterial circulation, the healthy endothelium generally exerts a vasodilator influence on the vascular smooth muscle. There are a number of methods to assess endothelial vasodilator function. The Endo-PAT 2000 is a new device that is used to assess endothelial vasodilator function in a rapid and non-invasive fashion. Unlike the commonly used technique of duplex ultra-sonography to assess flow-mediated vasodilation, it is totally non-operator-dependent, and the equipment is an order of magnitude less expensive. The device records endothelium-mediated changes in the digital pulse waveform known as the PAT ( peripheral Arterial Tone) signal, measured with a pair of novel modified plethysmographic probes situated on the finger index of each hand. Endothelium-mediated changes in the PAT signal are elicited by creating a downstream hyperemic response. Hyperemia is induced by occluding blood flow through the brachial artery for 5 minutes using an inflatable cuff on one hand. The response to reactive hyperemia is calculated automatically by the system. A PAT ratio is created using the post and pre occlusion values. These values are normalized to measurements from the contra-lateral arm, which serves as control for non-endothelial dependent systemic effects. Most notably, this normalization controls for fluctuations in sympathetic nerve outflow that may induce changes in peripheral arterial tone that are superimposed on the hyperemic response.
In this video we demonstrate how to use the Endo-PAT 2000 to perform a clinically relevant assessment of endothelial vasodilator function.

A noninvasive procedure to assess endothelial function is demonstrated using the Endo-PAT 2000.

评估与远藤的PAT 2000内皮血管舒张功能

The endothelium is a delicate monolayer of cells that lines all blood vessels, and which comprises the systemic and lymphatic capillaries. By virtue of ...

科研

医学

Non-invasive Assessment of Microvascular and Endothelial Function

The authors have utilized capillaroscopy and forearm blood flow techniques to investigate the role of microvascular dysfunction in pathogenesis of cardiovascular disease. Capillaroscopy is a non-invasive, relatively inexpensive methodology for directly visualizing the microcirculation. Percent capillary recruitment is assessed by dividing the increase in capillary density induced by postocclusive reactive hyperemia (postocclusive reactive hyperemia capillary density minus baseline capillary density), by the maximal capillary density (observed during passive venous occlusion). Percent perfused capillaries represents the proportion of all capillaries present that are perfused (functionally active), and is calculated by dividing postocclusive reactive hyperemia capillary density by the maximal capillary density. Both percent capillary recruitment and percent perfused capillaries reflect the number of functional capillaries. The forearm blood flow (FBF) technique provides accepted non-invasive measures of endothelial function: The ratio FBFmax/FBFbase is computed as an estimate of vasodilation, by dividing the mean of the four FBFmax values by the mean of the four FBFbase values. Forearm vascular resistance at maximal vasodilation (FVRmax) is calculated as the mean arterial pressure (MAP) divided by FBFmax. Both the capillaroscopy and forearm techniques are readily acceptable to patients and can be learned quickly.
The microvascular and endothelial function measures obtained using the methodologies described in this paper may have future utility in clinical patient cardiovascular risk-reduction strategies. As we have published reports demonstrating that microvascular and endothelial dysfunction are found in initial stages of hypertension including prehypertension, microvascular and endothelial function measures may eventually aid in early identification, risk-stratification and prevention of end-stage vascular pathology, with its potentially fatal consequences.

Capillaroscopy is a non-invasive, relatively inexpensive methodology for directly visualizing the microcirculation. The forearm blood flow technique provides accepted non-invasive measures of endothelial function.

非侵入性的评估微血管和内皮功能

The authors have utilized capillaroscopy and forearm blood flow techniques to investigate the role of microvascular dysfunction in pathogenesis of ...

Technical Aspects of the Mouse Aortocaval Fistula

Technical aspects of creating an arteriovenous fistula in the mouse are discussed. Under general anesthesia, an abdominal incision is made, and the aorta and inferior vena cava (IVC) are exposed. The proximal infrarenal aorta and the distal aorta are dissected for clamp placement and needle puncture, respectively. Special attention is paid to avoid dissection between the aorta and the IVC. After clamping the aorta, a 25 G needle is used to puncture both walls of the aorta into the IVC. The surrounding connective tissue is used for hemostatic compression. Successful creation of the AVF will show pulsatile arterial blood flow in the IVC. Further confirmation of successful AVF can be achieved by post-operative Doppler ultrasound.

The goal is to produce an arteriovenous fistula that is simple and reproducible. This method does not use sutures or glue adhesive. Therefore the samples can be used with the least amount of foreign materials for analysis.

在的鼠标Aortocaval瘘的技术方面

Technical aspects of creating an arteriovenous fistula in the mouse are discussed. Under general anesthesia, an abdominal incision is made, and the aorta ...

A Novel Application of Musculoskeletal Ultrasound Imaging

Ultrasound is an attractive modality for imaging muscle and tendon motion during dynamic tasks and can provide a complementary methodological approach for biomechanical studies in a clinical or laboratory setting. Towards this goal, methods for quantification of muscle kinematics from ultrasound imagery are being developed based on image processing. The temporal resolution of these methods is typically not sufficient for highly dynamic tasks, such as drop-landing. We propose a new approach that utilizes a Doppler method for quantifying muscle kinematics. We have developed a novel vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities using ultrasound. The goal of this preliminary study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task, in healthy subjects. The vTDI measurements can be performed concurrently with other biomechanical techniques, such as 3D motion capture for joint kinematics and kinetics, electromyography for timing of muscle activation and force plates for ground reaction force. Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.

We describe a new ultrasound-based vector tissue Doppler imaging technique to measure muscle contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities. This approach provides complementary measurements of dynamic muscle function and could lead to a better understanding of mechanisms underlying musculoskeletal disorders.

肌肉骨骼超声成像的一种新应用

Ultrasound is an attractive modality for imaging muscle and tendon  motion during dynamic tasks and can provide a complementary methodological  approach ...

Diagnostic Ultrasound Imaging of Mouse Diaphragm Function

Function analysis of rodent respiratory skeletal muscles, particularly the diaphragm, is commonly performed by isolating muscle strips using invasive surgical procedures. Although this is an effective method of assessing in vitro diaphragm activity, it involves non-survival surgery. The application of non-invasive ultrasound imaging as an in vivo procedure is beneficial since it not only reduces the number of animals sacrificed, but is also suitable for monitoring disease progression in live mice. Thus, our ultrasound imaging method may likely assist in the development of novel therapies that alleviate muscle injury induced by various respiratory diseases. Particularly, in clinical diagnoses of obstructive lung diseases, ultrasound imaging has the potential to be used in conjunction with other standard tests to detect the early onset of diaphragm muscle fatigue. In the current protocol, we describe how to accurately evaluate diaphragm contractility in a mouse model using a diagnostic ultrasound imaging technique.

Diagnostic ultrasound imaging has proven to be effective in diagnosing various respiratory diseases in human and animal subjects. We demonstrate a comprehensive ultrasound protocol utilized by Dr. Zuo's lab to analyze diaphragm kinetics specifically in mouse models. This is also a non-invasive research technique which can provide quantitative information on mouse respiratory muscle function.

小鼠膈肌功能诊断超声成像

Function analysis of rodent respiratory skeletal muscles, particularly the diaphragm, is commonly performed by isolating muscle strips using invasive ...

Ultrasound Assessment of Endothelial-Dependent Flow-Mediated Vasodilation of the Brachial Artery in Clinical Research

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The endothelium acts as a barrier, preventing leukocyte adhesion and aggregation, as well as controlling permeability to plasma components. Functionally, the endothelium affects vessel tone.
Endothelial dysfunction is an imbalance between the chemical species which regulate vessel tone, thombroresistance, cellular proliferation and mitosis. It is the first step in atherosclerosis and is associated with coronary artery disease, peripheral artery disease, heart failure, hypertension, and hyperlipidemia.
The first demonstration of endothelial dysfunction involved direct infusion of acetylcholine and quantitative coronary angiography. Acetylcholine binds to muscarinic receptors on the endothelial cell surface, leading to an increase of intracellular calcium and increased nitric oxide (NO) production. In subjects with an intact endothelium, vasodilation was observed while subjects with endothelial damage experienced paradoxical vasoconstriction.
There exists a non-invasive, in vivo method for measuring endothelial function in peripheral arteries using high-resolution B-mode ultrasound. The endothelial function of peripheral arteries is closely related to coronary artery function. This technique measures the percent diameter change in the brachial artery during a period of reactive hyperemia following limb ischemia.
This technique, known as endothelium-dependent, flow-mediated vasodilation (FMD) has value in clinical research settings. However, a number of physiological and technical issues can affect the accuracy of the results and appropriate guidelines for the technique have been published. Despite the guidelines, FMD remains heavily operator dependent and presents a steep learning curve. This article presents a standardized method for measuring FMD in the brachial artery on the upper arm and offers suggestions to reduce intra-operator variability.

Endothelial dysfunction is associated with numerous disease states and is predictive of adverse cardiovascular events in humans. Flow-mediated vasodilation (FMD) is a non-invasive ultrasound method of evaluating endothelial function. Methodological choices and operator experience may affect results. A systematic approach to FMD in human studies is discussed here.

肱动脉的临床研究超声评价血管内皮依赖性血流介导的血管舒张功能

The vascular endothelium is a monolayer of cells that cover the interior of blood vessels and provide both structural and functional roles. The ...

A Methodological Approach to Non-invasive Assessments of Vascular Function and Morphology

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis. Damage to the endothelium may predispose the vessel to atherosclerosis and increase the risk for cardiovascular disease. Assessments of peripheral endothelial function are good indicators of early abnormalities in the vascular wall and correlate well with assessments of coronary endothelial function. The present manuscript details the important methodological steps necessary for the assessment of microvascular endothelial function using laser Doppler imaging with iontophoresis, large vessel endothelial function using flow-mediated dilatation, and carotid atherosclerosis using carotid artery ultrasound. A discussion on the methodological considerations for each of the techniques is also presented, and recommendations are made for future research.

The present article describes the methodological considerations for several non-invasive assessments of vascular function and morphology that are commonly used in medical research to assess different stages of atherosclerosis.

方法论方法血管功能和形态的非侵入性评估

The endothelium is the innermost lining of the vasculature and is involved in the maintenance of vascular homeostasis.  Damage to the endothelium may ...

Ultrasound Assessment of Flow-Mediated Dilation of the Brachial and Superficial Femoral Arteries in Rats

Arterial vasodilation to increases in wall shear rate is indicative of vascular endothelial function. In humans, the non-invasive measurement of endothelial function can be achieved by employing the flow-mediated dilation technique, typically performed in the brachial or superficial femoral artery. Briefly, a blood pressure cuff placed distal to an ultrasound probe is inflated to a suprasystolic pressure, which results in limb ischemia. After 5 min of occlusion the cuff is deflated, resulting in reactive hyperemia and increases in wall shear rate that signal vasodilatory molecules to be released from the endothelium eliciting vasodilation. Despite the thousands of studies performing flow-mediated dilation in humans, surprisingly, no studies have performed this technique non-invasively in living rats. Considering the recent shift in focus to translational research, the establishment of guidelines for non-invasive measurement of flow-mediated dilation in rats and other rodents would be extremely valuable. In the following article, a protocol is presented for the non-invasive measurement of flow-mediated dilation in brachial and superficial femoral arteries of rats, as those sites are most commonly measured in humans.

Non-invasive assessment of endothelial function in humans can be determined by the flow-mediated dilation technique. Although thousands of studies have used this technique, no study has performed this technique non-invasively in rats. The following article describes non-invasive measurement of flow-mediated dilation in the brachial and superficial femoral arteries of rats.

肱血流介导的扩张和大鼠股浅动脉超声评估

Arterial vasodilation to increases in wall shear rate is indicative of vascular endothelial function. In humans, the non-invasive measurement of ...

Assessment of Human Adipose Tissue Microvascular Function Using Videomicroscopy

While obesity is closely linked to the development of metabolic and cardiovascular disease, little is known about mechanisms that govern these processes. It is hypothesized that pro-atherogenic mediators released from fat tissues particularly in association with central/visceral adiposity may promote pathogenic vascular changes locally and systemically, and the notion that cardiovascular disease may be the consequence of adipose tissue dysfunction continues to evolve. Here, we describe a unique method of videomicroscopy that involves analysis of vasodilator and vasoconstrictor responses of intact small human arterioles removed from the adipose depot of living human subjects. Videomicroscopy is used to examine functional properties of isolated microvessels in response to pharmacological or physiological stimuli using a pressured system that mimics in vivo conditions. The technique is a useful approach to gain understanding of the pathophysiology and molecular mechanisms that contribute to vascular dysfunction locally within the adipose tissue milieu. Moreover, abnormalities in the adipose tissue microvasculature have also been linked with systemic diseases. We applied this technique to examine depot-specific vascular responses in obese subjects. We assessed endothelium-dependent vasodilation to both increased flow and acetylcholine in adipose arterioles (50 - 350 &#181;m internal diameter, 2 - 3 mm in length) isolated from two different adipose depots during bariatric surgery from the same individual. We demonstrated that arterioles from visceral fat exhibit impaired endothelium-dependent vasodilation compared to vessels isolated from the subcutaneous depot. The findings suggest that the visceral microenvironment is associated with vascular endothelial dysfunction which may be relevant to clinical observation linking increased visceral adiposity to systemic disease mechanisms. The videomicroscopy technique can be used to examine vascular phenotypes from different fat depots as well as compare findings across individuals with different degrees of obesity and metabolic dysfunction. The method can also be used to examine vascular responses longitudinally in response to clinical interventions.

Videomicroscopy systems are used to examine functional properties of isolated adipose tissue arterioles in response to physiological and pharmacological stimuli. This technique can be used to examine microvascular phenotypes in different adipose tissue domains in obese humans.

应用 Videomicroscopy 评价人脂肪组织微血管功能

While obesity is closely linked to the development of metabolic and cardiovascular disease, little is known about mechanisms that govern these processes. ...

<meta charset="utf8"></head><body>使用动脉硬度和内皮功能进行心血管评估

Pulse-Wave Velocity, Flow-Mediated Dilation, and Carotid Intima-Media Thickness to Assess Cardiovascular Risk in Population with Metabolic Syndrome

Pulse-wave velocity (PWV), flow-mediated dilation (FMD), and carotid intima-media thickness (CIMT) are established methods used in research and clinical settings to assess arterial stiffness, endothelial function, and subclinical atherogenesis. These measurements may reflect vascular disease and atherosclerotic progression, which are major causes of adverse cardiovascular events. These methods are particularly valuable in determining cardiovascular dysfunction among populations with different risk factors, such as diabetes mellitus, hypertension, and other metabolic dysfunction-related conditions. They provide a non-invasive and reliable source of information that complements clinical practice. Early detection, risk assessment, and therapeutic decisions regarding cardiovascular disease can be achieved, ultimately contributing to improved patient outcomes. Traditional tools for evaluating cardiovascular disease do not reveal whether metabolic syndrome affects early subclinical cardiovascular disease in patients with obesity. Recent research has highlighted the importance of including arterial stiffness and endothelial function in a comprehensive cardiovascular assessment. Therefore, the aim of the present study is to describe methods that provide information on early subclinical vascular aging, endothelial dysfunction, and atherogenic disease, enabling vascular-targeted risk stratification among populations with obesity and different metabolic profiles.

<meta charset="utf8"></head><body>作者聚焦：评估代谢综合征患者的心血管特征

Endothelial/vascular aging and atherogenesis are key mechanisms that promote the development of cardiovascular diseases. The present protocol describes methods to evaluate arterial stiffness, endothelial dysfunction, and atherogenesis in patients with related risk factors, which are highly valuable in the cardiovascular research field.

脉搏波速度、血流介导的扩张和颈动脉内膜中层厚度评估代谢综合征人群的心血管风险

Pulse-wave velocity (PWV), flow-mediated dilation (FMD), and carotid intima-media thickness (CIMT) are established methods used in research and clinical ...