Experimental and comprehensive study to realize a nonpulsatile artificial heart

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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.