Experimental and clinical analysis of functional characteristics of intramyocardial microvessls and its disorders

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The purpose of this study was to clarify the physiological and pathophysiological role of intramyocardial capacitance vessels in the regulation of coronary circulation in animal experiment and clinical research. In anesthetized open-chest dogs coronary inflow(artery flow) coronary outflow(coronary vein flow) were measured by an optical fiber laser doppler velocimeter under control of coronary perfusion pressure. On the other hand, human coronary artery and vein flows were measured by an 80 channel 20 MHz ultrasound doppler velocimeter during cardiac surgery.Functional characteristics of intramyocardial capacitance vessels were composed of two factors: unstressed volumes(UV) and usual compliance. The characteristics of UV is fitted to store blood and its capacity is found to be 5ml/100g of LV. The coronary inflow resistance increased without significant changes of zero-flow pressure, when UV was filled with blood. The phasic coronary vein flow was mainly regulated by the blood stored within intramyocardial vessels. The rheological property of blood had effects on not only inflow resistance but also zero-flow pressure of the coronary artery. The fluid dynamics of the human poststenotic coronary artery folw was analyzed by 20MHz 80 Channel ultrasound Doppler velocimeter during cardiac surgery. the phasic characteristics of coronary artery folw in pressure overload human hypertrophy was also clarified. We developped dual-core optical fiber laser doppler velocimeter, which is useful for the measurement of blood flow away from the fiber and disturbed flow.