VASCULAR STIFFNESS & CARDIOVASCULAR FUNCTION IN ELDERLY

描述（改编自申请人的摘要）：长期 本研究的目的是了解 在搏动性动脉负荷、左心室（LV）机械能 性能，以及老年人的LV和血管重塑。 已经 假设动脉僵硬度增加与 老年人单纯收缩期高血压（ISH）的发生，可能代表 心血管危险因素。 该提案的具体目标是 特征：（1）动脉僵硬度的独立影响（两者 大小和分布）对耦合的机械性能的影响 左室-动脉系统和左室能量学;（2）ISH的力学决定因素 老年ISH患者的动脉僵硬度增加;（3） 动脉和LV机械性能的时间变化， 确定ISH的心血管起始因子。 假设：（1） 压力超负荷的心脏对动脉的变化更敏感 刚度，从机械和能量的角度来看;（2）增加 动脉僵硬度是ISH的必要但非充分条件， 发生;其他心血管因素必须共存;（3）增加 动脉硬化，特别是区域再分布，先于 ISH的发生。 在离体兔心制备中， 机械能数据将使用正常和 压力超负荷的心脏 使用非侵入性和侵入性技术， 将在150名非裔美国受试者中评估心血管功能 分为三组（正常，合并收缩期-舒张期高血压， 的ISH）。 动脉系统的定量表征将 包括输入阻抗谱和局部压力-直径-脉搏波 速度关系 左心室大小、形状、质量和指数 收缩性（心室和心肌）和耗氧量将 量化。 200名受试者来自高发病率人群， 高血压（来自南达科他州的赫特人）将参加一个 纵向研究 使用非侵入性技术，纵向研究 将量化动脉和LV特性的时间变化 发展ISH。

DESCRIPTION (adapted from the applicant's abstract): The long-term objectives of the proposed research are to understand the relationships among pulsatile arterial load, left ventricular (LV) mechano-energetic performance, and LV and vascular remodeling in the elderly. It has been hypothesized that increased arterial stiffness is causally linked to the genesis of isolated systolic hypertension (ISH) in elderly and may represent a cardiovascular risk factor. The specific aims of the proposal are to characterize: (1) the independent effects of arterial stiffness (both magnitude and distribution) on the mechanical performance of the coupled LV-arterial system and LV energetics; (2) the mechanical determinants of ISH and of increased arterial stiffness in elderly population with ISH; and (3) the temporal changes in arterial and LV mechanical properties in order to identify the cardiovascular initiating factor(s) for ISH. Hypotheses: (1) The pressure-overloaded heart is more sensitive to the changes in arterial stiffness, both from mechanical and energetic viewpoints; (2) Increased arterial stiffness is a necessary but not sufficient condition for ISH to occur; other cardiovascular factors must coexist; and (3) Increase in arterial stiffness, especially regional redistribution, precedes the occurrence of ISH. In the isolated rabbit heart preparation, mechano-energetic data will be acquired using both normal and pressure-overloaded hearts. Using noninvasive and invasive techniques, cardiovascular function will be evaluated in 150 African-American subjects divided into three groups (normal, combined systolic-diastolic hypertension, and ISH). Quantitative characterizations of the arterial system will include input impedance spectrum and regional pressure-diameter-pulse wave velocity relationships. LV size, shape, and mass and indices of contractility (chamber and myocardial) and oxygen consumption will be quantified. Two hundred subjects from a population with high incidence of hypertension (the Hutterites from South Dakota) will participate in a longitudinal study. Using noninvasive techniques, the longitudinal study will quantify the temporal changes in arterial and LV properties during the development of ISH.