PULMONARY PRESSURE AND VALVE ASSESSMENT BY SOUND

本建议的目的是探讨衡量 猪生物瓣膜的关闭声音的频率， 确定早期和亚临床变性是否可以通过这种检测 非侵入性方法。 请求继续执行的具体目标 这项调查是为了确定是否改变频率的 在临床前可以检测到生物瓣膜的关闭声音 退化的迹象变得明显。 重要的是要知道如何 频率的变化很快先于退行性变的临床证据， 变化 我们已经证明，心音的主频率在 患有自发性退化的猪生物瓣膜的患者， 当退化的瓣膜变硬时， 钙或纤维化。 我们还表明， 生物瓣膜的关闭声音在五年后更高， 比在前18个月插入。 这表明， 逐步发生。 这些观察结果是可以预测的， 这是可以理解的，因为膜的硬化增加了 振动的自然频率。 现在我们知道 生物瓣膜的关闭声音的频率随着 插入的持续时间，这将是有益的实际应用， 方法，以了解频率的变化如何与 个体患者的临床状态，以及在何种程度上可测量 频率的变化是未来临床退化的预测， 生物瓣膜

The object of this proposal is to explore the usefulness of measurement of the frequency of the closure sounds of porcine bioprosthetic valves to determine if early and subclinical degeneration can be detected by this non-invasive method. The specific goal of the requested continuation of this investigation is to determine if changes of the frequency of the closure sound of bioprosthetic valves can be detected before clinical evidence of degeneration becomes apparent. It is important to know how soon changes of the frequency precede clinical evidence of degenerative changes. We have shown that the dominant frequency of heart sounds in patients with spontaneously degenerated porcine bioprosthetic valves is abnormally elevated when the degenerated valves are stiffened due to calcium or fibrosis. We also showed that the frequency content of the closure sounds of bioprosthetic valves is higher after five years of insertion than during the first 18 months. This suggests that stiffening progressively occurred. These observations were predictable and understandable on the basis that stiffening of a membrane increases the natural frequency with which it vibrates. Now that we know that the frequency of the closure sound of bioprosthetic valves increases with the duration of insertion, it would be useful for practical application of the method, to know how changes of the frequency relate to changes of the clinical status of individual patients, and to what extent measurable changes of frequency are predictive of future clinical degeneration of the bioprosthetic valve.