Development of a mock circulatory system as a supporting tool to propose the oprimal cardiac surgery

为了评估心血管疾病手术治疗中几种人工器官的功能，一种原始设计的模拟循环系统（MCS）已经被开发出来。本系统的特点是能够模拟主动脉血管假体中的血流动力学，并通过计算机控制具有左心室自然收缩的机械可行性。由于动脉血管移植物的力学性能不同于弹性天然动脉，推测其顺应性较低，可能导致移植物植入后左心室后负荷升高。通过将血流切换到与狗的自然降主动脉平行插入的旁路移植术，特征阻抗提高了2.6倍，心输出量减少了14%，根据左心室压力-容积关系计算的心功增加了1.5倍。MCS也被用来表示血流动力学特征，并与动物实验数据进行比较。当机械驱动泵将MCS的流量设置为4L/min时，左室模型动脉系统的特征阻抗和外功分别增加2.4倍和1.5倍。因此，可以预见，移植后动脉阻抗的增加会增加心脏外功。

An originally-designed mock circulatory system (MCS) has been developed in order to evaluate functions of several types of artificial organs for the surgical treatment of cardiovascular deseases. The features of the present MCS has a capability of exhibiting a practical simulation of hemodynamics in aortic vascular prostheses, and of having a mechanical feasibility of the natural left ventricular contraction by the computer-based control.As mechanical properties of arterial vascular grafts are different from those of elastic natural arteries, it can be speculated that the left ventricular afterload might be elevated after the graft implantation due to its low compliance. By switching blood flow to a bypass graft which was inserted in parallel with the natural descending aorta of dog, the characteristic impedance was elevated by 2.6 times, furthermore, the cardiac output was decreased by 14%, and the cardiac work calculated from the pressure-volume relationships in the left ventricle, was increased by 1.5 times. MCS was also employed to represent hemodynamic characteristics as well as to compare the data with those in animal experiments. When the flow was set to 4L/min in MCS by the mechanical driven pump, either characteristic impedance of the arterial system or external work of the left ventricular model was increased by 2.4 or 1.5 times, respectively. Thus, it was anticipated that the external cardiac work would be elevated by the increase of the arterial impedance after the graft implantation.