Comprehensive research concerned with the influence of flow state of artificial heart on living body by observation of microcirculation

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Although many types of continuous flow ventricular assist devices have become to use clinically as the bridge to heart transplantation, no body knows whether the pulsatility of blood flow is essential for living body or not. We have succeeded the basic development to solve the problem ; undulation pump AH(UPAH) and CCD probe. UPAH can change instantaneously its flow patterns by computer control of motor rotational speed. CCD probe is implantable micro-camera to observe microcirculation chronically.The objective of this study is to clarify the necessity of pulsatility for the living body by developing more completely UPTAH and CCD probe. The following outcome has been gotten in these 4 years :1)UPAHBlood compatibility, durability and size ＆ weight were improved great deal. The goat implanted UPAH survived maximally 4 months without anticoagulant. The software to control blood waveform has also been developed.2)CCD probeHigh magnification, focus adjust system and miniaturization were the objective to be developed. A micro-lens, 2 mm in diameter and 2 mm long was developed. The lens was installed into a CCD camera having 8 mm in diameter and 60 mm long. Total magnification on 14 inch TV screen was 650 times, that was enough to observe the erythrocyte flow in a capillary vessel. It could be implanted in an animal without difficulty. Residual problem is focus adjusting system.3)Microcirculation under UPAHThe blood flow pattern was changed instantaneously from pulsatile to continuous when UPAH goat recover from surgical stress. The microcirculation was observed at bulbar conjunctiva during experiment. Following phenomena were observed until now : (1)Capillary density that is the ratio of the flowing capillaries to total capillary number, was decreased 30%. (2)The erythrocyte flow rate in the capillary was decreased 75 and some of them did not recover after the flow pattern returned to pulsatile.