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

为了评价心血管外科手术中几种人工器官的功能，研制了一种自主设计的模拟循环系统（MCS）。本MCS的特点是能够实际模拟主动脉人造血管中的血液动力学，并通过计算机控制具有自然左心室收缩的机械可行性。由于动脉血管移植物的机械性能不同于弹性天然动脉的机械性能，可以推测，移植物植入后左心室后负荷可能由于其低顺应性而升高。通过将血流转换到与犬降主动脉平行插入的旁路移植物，特征阻抗提高了2.6倍，心输出量降低了14%，由左心室压力-容积关系计算的心脏功增加了1.5倍。MCS也被用来代表血流动力学特征，以及与动物实验中的数据进行比较。当MCS中的流量被机械驱动泵设置为4L/min时，动脉系统的特征阻抗或左心室模型的外功分别增加2.4和1.5倍。因此，可以预期，移植物植入后，动脉阻抗的增加会提高心脏外功。

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.