PULMONARY PRESSURE AND VALVE ASSESSMENT BY SOUND

这项建议的目的是探索测量的有效性 猪生物瓣膜关闭声的频率 确定是否可以通过此方法检测早期和亚临床退行性变 非侵入性方法。所要求的延续的具体目标 这项调查是为了确定频率的变化是否 临床前可检测到生物瓣膜关闭的声音 退化的证据变得很明显。重要的是要知道如何 在退行性疾病的临床证据出现之前，频率很快就发生了变化 改变。我们已经证明心音的主要频率在 自发性退行性猪生物瓣膜患者 当退化的阀门因以下原因而变硬时异常升高 钙质或纤维化。我们还表明，频率的含量 五年后生物瓣膜关闭的声音更高 插入的时间比前18个月要短。这表明僵化 逐渐发生的。这些观察是可以预见的，而且 可以理解的是，膜的硬化增加了 它振动的自然频率。现在我们知道了 生物瓣膜关闭声的频率随时间的延长而增加 插入的持续时间，这将有助于实际应用 方法，以了解频率的变化与频率的变化的关系 个别患者的临床状况，以及可测量的程度 频率的变化预示着未来的临床退行性变 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.