搏动心室卸载改善心脏功能的左室壁应力特性研究

Heart failure is a serious and high incident cardiovascular disease. Recently, pulsatile ventricular unloading is proved as an effective clinical therapy method, and the changing in the left ventricular wall stress (LVWS) is considered as one of the key reasons. Unfortunately, the mechanism itself is not clear nor how to achieve it. Aim at these problems, this project plans to clarify the biomechanical mechanism of the cardiac function recovery caused by the pulsatile ventricular unloading, and to reveal the law between the blood assist index (BAI), pulsatile ratio (PR), the characteristics of swirling flow and the changes in the function and structure of myocardium, as well as to propose the judgement of optimal pulsatile unloading mode. The contents of the research are as fallow. Firstly, study the distribution and changing of VSS caused by blood assist index and pulsatile ratio by means of numerical simulation to clarify the biomechanical principle of heart failure therapy by pulsatile unloading. Secondly, conducting animal trial to clarify the effects of BAI, PR and LVWS on the cardiac functional parameters, and to discover the rule of unloading lead inverse remodeling of the myocardium. Thirdly, model study on optimal unloading accelerating inverse remodeling of the myocardium by optimizing the pulsatile ventricular unloading mode. At the time when the project finished, we will provide the theory support and a clinical guide for unloading therapy hears failure.

心力衰竭是严重且高发的心血管病。临床证据表明搏动心室卸载是一种有效的治疗手段，其中左心室壁应力特性的改善被认为是重要原因之一。然而，搏动卸载对左心室壁应力的改善机理尚不清楚，临床应用层面上最佳的搏动卸载模式尚未明确。针对上述问题，本项目计划阐明搏动心室卸载促进心脏功能恢复的生物力学机理；揭示血流辅助指数与搏动率对左室壁应力特性以及心肌组织的结构改变规律；提出最佳卸载模式判据。具体研究内容为：第一，采用数值模拟方法研究血流辅助指数与搏动率对左室壁应力特征参数的影响规律；第二，通过动物试验研究血流辅助指数、搏动率以及左室壁应力特性对心脏功能重要参数的影响规律；第三，采用模型研究方法确定促进心脏功能恢复的最佳搏动心室卸载模式。项目的完成可以为搏动心室卸载治疗心衰提出理论支持并提供临床指导。

目前心衰治疗集中在维持血液灌注，而其对左心室的血流动力学影响机制尚不明确。为了明确上述机制，本研究开展三方面研究。首先采用集中参数模型与流固耦合相结合的方法研究不同辅助水平对左心 室生物力学特性的影响机制。然后采用实验方法确定血流辅助指数与血流动力学参数、心脏功能参数之 间的变化规律。最后，采用模型研究方法建立面向心脏功能回复的血流动力学控制模型。本项目按照计 划进行，取得如下结果：第一，对比心衰情况，部分辅助增加心室内涡流形成时间与涡流强度，且高震 荡剪切应力区域减小；第二，心尖-升主动脉搭桥方式下，脉动性指标随转速的增加均无持续降低现 象；第三，采用“替代数据分析”算法确定心衰钙离子模型中肌钙蛋白浓度、BNP浓度、SHE与EEP指 标的权重分别为0.2，0.33，0.28与0.19，采用非参数模型自适应控制理论建立面向新功能回复的心室辅助 水平确定策略。