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外科治疗中几种人工器官的功能，开发了一种最初设计的模拟循环系统(MCS)。由于动脉血管移植物的力学特性与弹性天然动脉不同，因此可以推测，移植物的顺应性较低，可能会导致移植后左室后负荷的增加。将血流转换为与犬自然降主动脉平行置入的旁路移植物，使特征阻抗增加2.6倍，心输出量减少14%，由左心室压力-容量关系计算的心功增加1.5倍。MCS也被用来表示血流动力学特性，并将数据与动物实验中的数据进行比较。机械驱动泵将MCS流量设置为4L/min时，动脉系统的特征阻抗和左心室模型的外功分别增加2.4倍和1.5倍。因此，预计移植血管植入后动脉阻抗的增加会增加心外做功。

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.