Experimental and comprehensive study to realize a nonpulsatile artificial heart

研制了离心泵（CP）系统作为长期使用的人工心脏，并在人体急、慢性动物实验中研究了活体对非搏动体循环的病理生理反应。为此，我们开发了一种无密封无轴CP，NCVC-2，叶轮周围具有自灌血功能。对该泵的可行性进行了评估，包括其抗血栓性、耐用性、安全性和作为长期装置的植入式以及非搏动循环的生理可行性。左心室CP直径60 mm，长100 mm，植入山羊胸部，维持4-5 L/min，温升在2ºC以内。在山羊体内进行了体外左心搭桥，实验结果表明，CP具有良好的抗血栓性、耐久性和安全性。体外溶血试验中，CP的溶血率低于Bio-pump。在急性、麻醉动物实验和清醒动物实验中评估对无搏动的全身和肺循环的生理反应。在急性实验环境中，交感神经活动和血液去甲肾上腺素在体循环搏动性消失后立即升高，但在几分钟内恢复到非搏动性循环前的水平。在清醒状态下，大部分参数如血流动力学参数、血管活性物质、肾素-血管紧张素系统和全身非搏动血流代谢参数没有变化。通过一系列慢性动物实验研究了长时间无搏动左心搭桥术后主动脉壁的形态学变化。无搏动动物主动脉壁厚度明显变薄，平滑肌细胞体积比明显降低。

A centrifugal pump (CP) system were developed as an artificial heart for long term usage and pathophysiological reactions of living bodies to nonpulsatile systemic circulation were investigated in boty acute and chronic animal experiments. we developed a no-seal and no-shaft CP,NCVC-2, featuring self-blood-irrigation around the impeller for this purpose. The feasibility of the pump was assessed in terms of its performances including antithrombogenicity, durability, safety and implantablity as a long-term device and of physiological feasibility of nonpulsatile circulation. The size of the CP for the left ventricle was 60 mm in diameter and 100 mm in length, was implanted inside the chest of a goat and maintained 4-5 L/min and the temperature rise was within 2ﾟC.The CP was installed in goats as a paracorporeal left heart bypass and could be driven for 381 days in an animal, and proved to have good antithrombogenicity, durability and safety. The hemolysis rate of the CP was lower than Bio-pump in in vitro hemolysis tests. Physiological reaction to the nonpulsatile systemic and pulmonary circulation was evaluated in acute and anesthetized animal experiments and in awake animals. In the acute experimental setting, sympathetic nerve activity and blood noradrenalin increased immediately after the disappearance of pulsatility of systemic circulation but returned to the levels before the nonpulsatile circulation in a few minutes. Most of the parameters did not change in awake animals such as hemodynamic parameters, vasoactive substances, renin-angiotensin system and metabolic parameters with systemic nonpulsatile flow. Morphological changes of the aortic wall in prolonged nonpulsatile left heart bypass were investigated in a series of chronic animal experiments. The wall thickness of the aortic wall in nonpulsatile animals was significantly thinner and the volume ratio of the smooth muscle cells was lower.