EFFECTS OF AGE ON LIMB ARTERIAL COMPLIANCE

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。随着人类年龄的增长，血管系统中许多不同类型的变化可能是血管功能下降的核心。功能下降的一个关键因素似乎是血管壁机械特性的变化以及它们对血压变化的反应。血管顺应性是指血管随内部压力变化而扩张的程度，即每次心脏跳动时血管壁移动的程度。我们开发了一种软件，可以同时记录来自无创血压监测仪的血压跟踪和来自无创表面应变计的小腿体积变化，每次心脏跳动，以获得整个小腿的顺应性。本项目将该技术与通常使用多普勒超声和无创血压监测评估单血管顺应性的方法相结合，比较整个小腿与供血小腿血管床的大动脉腘动脉的顺应性。这样做是为了比较血管顺应性的年龄相关变化（来自多普勒成像和血压追踪）与整个肢体顺应性的年龄相关变化（来自表面应变仪和血压追踪），这反映了肢体大血管和小血管系统的变化，而这些变化本身不容易研究。测量将在休息和适度加热（大约普通桑拿的温度）时进行，只是为了引起局部较高的血流量，而不会引起任何心血管疾病或不适。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Many different types of changes in the vascular system may be at the heart of decreased blood vessel function with aging in humans. A key factor in this decrement in function appears to be changes in mechanical properties of the vessel walls and how they respond to blood pressure changes. Compliance of blood vessels is their distensibility in response to pressure changes inside them, i.e. how much the vessel walls move every time the heart beats. We have developed a software that can simultaneously record blood pressure tracings from a noninvasive blood pressure monitor and changes in calf volume from a noninvasive surface strain gauge every time the heart beats to derive whole calf compliance. This project will combine this technology with the method generally used to assess single vessel compliance using Doppler ultrasound and noninvasive blood pressure monitoring to compare whole calf compliance with that of the major artery feeding the calf vascular bed, the popliteal artery. This will be done to compare age-related changes in vessel compliance (from Doppler imaging and blood pressure tracings) with age-related changes in whole limb compliance (from surface strain gauge and blood pressure tracings) which reflects changes in the large vessels in the limb and the small vasculature that cannot be easily studied on its own. Measurements will be made during rest and moderate heating (about the temperature of a common sauna) of one calf and foot only to induce a locally higher blood flow without causing any cardiovascular distress or discomfort.