心室辅助下心血管系统血流动力学的模型研究

发布时间：2018-04-26 19:31

本文选题：心力衰竭 + 心血管系统　；参考：《北京工业大学》2012年硕士论文

【摘要】：心力衰竭已日益成为威胁人类健康的因素之一。晚期心衰主要采取心脏移植和心室辅助两种治疗手段，由于心脏供体不足，使得心室辅助得到广泛关注和大力发展。心室辅助装置是一种部分或全部替代心脏泵功能的设备，为血液循环系统提供动力。心血管系统是一个多参数强耦合的系统，其生理调节机制可以反映人体生理参数间相互关系。而心衰患者处于失代偿状态，该状态下心血管系统的调节机制发生改变，这种变化迄今尚未明确。此外，左心室辅助治疗心衰会改变心血管系统的血流动力学特性，其辅助方式以及控制策略对器官灌注与心功能恢复的血流动力学机理研究未见明确结论。本文针对上述心衰患者生理调节机制与左心室辅助对心血管血流动力学影响这两个问题，通过构建心肌收缩力、外周阻力和血管顺应性等生理参数模型研究心衰生理调节机制；通过构建心血管-血泵耦合模型研究血泵辅助后血流动力学变化。首先，对心血管系统进行了模型研究，包括依据临床数据建立的心肌收缩力模型、用于研究调节机制的外周阻力与血管顺应性模型、研究心血管与血泵相互作用的心血管-血泵耦合模型。其次，对心血管与血泵相互作用进行了数值研究。开发了心血管模拟系统，利用该系统研究了由心尖到主动脉的并联方式与由主动脉根到主动脉弓的串联方式对器官灌注与心功能恢复的影响，以及恒流、恒速与恒压差三种不同的控制策略对串联辅助下心室卸载与血管的影响。最后，本论文进行了左心室辅助对心血管系统影响的动物实验研究。开发了具有生理参数采集与血泵控制等功能的动物实验系统。利用此系统建立左心辅助动物模型，并将模拟数据与实验数据进行了对比，并依据动物实验数据，对左心室辅助下心室卸载、器官灌注与搏动性等血流动力学参数进行了研究。研究结果表明，第一，本文建立的心衰模型可反映患者血流动力学特性。第二，动物实验采集的左心室压和主动脉压与模拟结果趋势一致，模型可反映心血管血流动力学特性。第三，串联辅助下，恒压差控制策略具有较优的心室卸载与器官灌注效果，并能产生与心脏射血同步的搏动性血流；并联辅助下，恒速控制策略产生的器官灌注效果最佳，恒流控制策略产生更好的心室卸载；随着辅助指数的增大搏动指数逐渐降低。第四，动物实现表明，，随着转速的增加器官灌注与心室卸载增大，搏动性降低，此结果与数值研究结果一致。总之，本文对心室辅助下心血管系统血流动力学模型的研究为心衰的临床治疗提供了理论模型依据，并为长期心室辅助的辅助方式及其控制策略提出了几点临床指导意见。
[Abstract]:Heart failure has increasingly become one of the factors threatening human health. Late heart failure is mainly treated by heart transplantation and ventricular assistance. Due to the shortage of heart donors, ventricular assistance has been widely concerned and developed. Ventricular assist is a device that partially or wholly replaces the function of cardiac pump and provides power to the circulatory system. Cardiovascular system is a multi-parameter strong coupling system, its physiological regulation mechanism can reflect the relationship between human physiological parameters. However, patients with heart failure are in a state of decompensation under which the regulatory mechanism of the cardiovascular system has changed, which has not yet been clarified. In addition, left ventricular adjuvant treatment of heart failure will change the hemodynamic characteristics of cardiovascular system. There is no clear conclusion on the hemodynamic mechanism of organ perfusion and cardiac function recovery by its auxiliary mode and control strategy. In this paper, the physiological regulation mechanism of heart failure patients and the effects of left ventricular assist on cardiovascular hemodynamics were studied by constructing physiological parameter models of cardiac contractility, peripheral resistance and vascular compliance. The hemodynamic changes of blood pump assisted by blood pump were studied by establishing a cardiovascular-blood pump coupling model. First, the cardiovascular system model was studied, including the myocardial contractility model based on clinical data, which was used to study the peripheral resistance and vascular compliance model of regulatory mechanism. The coupling model of cardiovascular and blood pump was studied. Secondly, the interaction between cardiovascular and blood pump is studied numerically. A cardiovascular simulation system was developed to study the effects of a parallel approach from the apex to the aorta and a series from the root of the aorta to the aortic arch on organ perfusion and cardiac function recovery, as well as the constant-current. Effects of three different control strategies, constant velocity and constant pressure difference, on ventricular unloading and vascularization assisted in series. Finally, an experimental study on the effects of left ventricular assist on cardiovascular system was carried out. An animal experimental system with physiological parameter collection and blood pump control was developed. The left ventricular assisted animal model was established by this system, and the hemodynamic parameters such as left ventricular assisted ventricular unloading, organ perfusion and pulsatility were studied according to the experimental data. The results show that, first, the heart failure model can reflect the hemodynamic characteristics of patients. Second, the trends of left ventricular pressure and aortic pressure collected in animal experiments are consistent with the simulated results. The model can reflect the characteristics of cardiovascular hemodynamics. Third, the constant-pressure difference control strategy has better effects of ventricular unloading and organ perfusion, and can produce pulsatile blood flow synchronously with cardiac ejection, and the organ perfusion effect of constant-velocity control strategy is the best with parallel assistance. Constant flow control strategy produces better ventricular unloading, and pulsatile index decreases with the increase of auxiliary index. Fourth, animal realization showed that organ perfusion and ventricular unloading increased with the increase of rotational speed, and pulsatility decreased, which was consistent with the numerical results. In conclusion, the study of the cardiovascular system hemodynamic model under ventricular assistance provides a theoretical model basis for the clinical treatment of heart failure, and provides some clinical guidance for the long-term ventricular assistant mode and its control strategy.
【学位授予单位】：北京工业大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：R312

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