用左心室涡流参数评估早期心衰心脏功能的数值模拟与实验研究

The pathological process of heart failure is accompanied by the change of interventricular flow field. Abnormal left ventricular vortex is one of cause of left ventricular dysfunction. However, the quantitative relationship between left ventricular vortex and cardiac function is not yet clear. In our preliminary study of dogs, we found that left ventricular vortex is related to cardiac function. Moreover, early heart failure showed normal ventricular anatomic structure by ultrasound, but the formation time and the distribution of ventricular vortex was changed. Therefore, it was assumed that there exists the correlation between the left ventricular vortex and cardiac function and left ventricular vortex has the function of the early evaluation of cardiac function. In this project, we plan to solve these problems in 3 aspects as follows. Firstly, dog chronic heart failure model is established to analysis the distribution of blood flow, left ventricle vortex and cardiac function. Secondly, the numerical simulation is carried out to quantitative study the hemodynamic characteristics of left ventricular and the relationship between left ventricular vortex and cardia function. Thirdly, the early evaluation parameters are proposed accord to the study in patients. As the project finished, the fundamental theory that the early evaluation of heart failure by left ventricular vortex will be established, and it has to be a clinical guidance.

心衰病变过程伴随着心室内部流场的改变。异常的左心室涡流是造成左心室功能障碍的因素之一。然而，左心室涡流参数与心功能参数间的定量关系尚不清楚。我们在犬的预试验发现左心室涡流与心功能有一定关系，并且在早期心衰超声显示心室解剖结构正常的情况下，心室内涡流的形成时间与涡流分布发生了改变，由此假设左心室涡流与心功能具有相关性，并能用于定量评估早期心衰心脏功能。为此，本项目对左心室涡流参数早期评估心衰心脏功能开展研究，第一，利用犬压力负荷慢性心衰模型，对照生理与心衰病理下左心室血流分布以及左心室涡流特性的变化规律；第二，采用数值模拟方法研究心衰病理下定量分析左心室涡流参数与心功能参数之间的关系；第三，通过临床测量左心室涡流参数验证具有评估心功能价值的血流动力学参数。项目的完成可以为血流动力学在心衰早期评估心功能奠定理论基础并提供临床指导。

在项目执行过程中，项目负责人严格按照研究计划开展工作。本项目构建了球囊式导管制备比格犬慢性心力衰竭模型的新方法，同时结合数值计算与临床数据，研究左心室涡流在心衰发生与发展过程的变化规律。研究结果表明，射血分数明显降低与BNP明显升高指示心衰发生，此时前射血时间与射血时间比值PET/ET和Qbs明显升高，心肌细胞排列紊乱伴随肥大，且随着心衰的发生、发展，比格犬左室能量耗散、室壁应力及涡流呈现下降趋势。数值计算结果显示，左心室涡在等容收缩期持续减小且涡强度明显减小，心尖附近区域血液振荡且停滞时间长。临床数据同样证实心衰组对比正常组在能量损失与血流组分等参数有显著性差异，心衰早期心室残余血液已发生改变，与左心室涡流直接相关。综上所述，本项目采用数值模拟、动物实验和临床研究相结合的方法展开左心室涡流参数评估早期心衰心脏功能的研究，初步探明了左心室内血流分布、左心室涡流与心功能变化规律，涡强度、涡持续时间、能量耗散和血液停滞等参数与心功能参数间的关系，为进一步验证左心室涡流参数（能量损失、血流组分）的临床价值提供了基础。本项目的研究结果有望为血流动力学在心衰早期评估心功能方面奠定理论基础并提供临床指导。