VASCULAR STIFFNESS & CARDIOVASCULAR FUNCTION IN ELDERLY

描述(改编自申请人的摘要)：长期 拟议研究的目标是了解这些关系 在搏动性动脉负荷中，左心室(LV)机械能 表现，与老年患者的左室和血管重构有关。一直以来 假设动脉僵硬的增加与 老年单纯收缩期高血压(ISH)的发病机制 心血管危险因素。这项建议的具体目的是 特征：(1)动脉僵硬的独立效应(两者 大小和分布)对联轴器的力学性能的影响 左动脉系统与左心室能量学；(2)高血压病的力学决定因素 老年ISH患者的动脉硬化增加；以及(3) 动脉和左心室机械特性的时间变化 确定ISH的心血管启动因子(S)。假设：(1) 压力超负荷的心脏对动脉的变化更敏感。 从机械和能量的观点来看，僵硬；(2)增加 动脉僵硬是ISH的必要条件，但不是充分条件。 发生；其他心血管因素必须共存；以及(3) 动脉僵硬，特别是区域再分配，先于 ISH的发生。在离体兔心脏制剂中， 机械-能量数据将使用常规和 压力超负荷的心脏。使用非侵入性和侵入性技术， 将评估150名非裔美国人的心血管功能 分为正常组、收缩-舒张期高血压组、 和ISH)。动脉系统的定量特征将 包括输入阻抗谱和区域压力-直径-脉搏波 速度关系。LV的大小、形状、质量和指数 收缩能力(心腔和心肌)和耗氧量将 量化的。来自高发人群的200名受试者 高血压(来自南达科他州的哈特利派)将参加 纵向研究。利用非侵入性技术，进行纵向研究 将量化动脉和左心室特性在 ISH的发展。

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.