Development of Noninvasive Estimation system of Maximum Ventricular Elastance Emax for Clinical Application

最大心室弹性（Emax）是评价心脏泵功能的较好的定量指标。为了更广泛地推广Emax的临床应用，需要一种新的无创测量Emax的方法。本研究的目的是开发一种临床方法来估计Emax的低侵入性无任何心脏负荷的参数优化方法（POM）和线性弹性方法（LEM）的作者已经提出的。由于POM和LEM需要左心室压力（LVP）和主动脉流量（AoF），我们还开发了一种技术来估计这些信号在以下方面。（自回归外生）模型：分别为从桡动脉压（RdP）到主动脉压（AoP）的系统模型和从AoP到LVP的系统模型;在心导管检查中，这些ARX模型可以通过使用LVP、AoP和RdP来识别。LVP和AoP是有创测量，但RdP是通过眼压传感器无创测量的。一旦识别出这些模型，就可以推测，即使在先前的心导管检查之后，也可以通过使用RdP完全无创地估计LVP。其次，所开发的系统可以通过自动提取射血期多普勒超声心动图的轮廓来估计AoF。最后，整个系统已经在个人计算机单元中完成，以便使用off-RdP线数据和主动脉血流速度多普勒图像。系统中增加了一个输入模块，以将系统应用于真实的临床使用。

The maximum ventricular elastance (Emax) is a good quantitative index for evaluating cardiac pump function. To extensively promote clinical application of Emax, it is necessary to need a new method for obtaining Emax without high invasive measurements. The purpose of this research was to develop a clinical method for estimating Emax low-invasively without any cardiac load on the of the parameter optimization method (POM) and the linear elastance method (LEM) that has been proposed by the authors. Because the POM and LEM need left ventricular pressure (LVP) and aortic flow (AoF), we have also developed a technique to estimate these signals in the following.First, the system we have developed can estimate LVP on the basis of two ARX (autoregressive exogeneous) models : the system model from radial arterial pressure (RdP) to aortic pressure (AoP) and the system model from AoP to LVP, respectively ; In a cardiac catheterization test, these ARX models can be identified by using LVP, AoP and RdP. LVP and AoP are invasive measurements but RdP is measured noninvasively by a tonometric pressure sensor. Once these models are identified, it is guessed that LVP can be estimated fully noninvasively by using RdP even after the previous cardiac catheterization test.Secondly, the developed system can estimate AoF by automatically extracting the contour of Doppler echocardiography during the ejection period.Finally, the total system has been completed in a personal computer unit so as to estimate Emax on the basis of the POM using the off-line data of RdP and the Doppler image of aortic flow rate. An input module has been added to the system to apply the system to real clinical use.