A Study of Coronary Circulation by Laser Doppler Velocimetry

Abstract

Our laser Doppler velocimeter (LDV) with an optical fiber is a powerful tool for the measurement of both coronary artery and vein flow velocities because of its excellent accessibility to coronary vessels of the beating heart. We designed four different accesses of a fiber probe to measure blood velocities, depending upon the objectives of the measurements, i. e., epicardial large coronary vessels, the epicardial small artery and vein, the intramyocardial artery and vein, and a laser catheter. The blood flow velocities showed a diastolic-predominant pattern in the coronary artery and a systolic-predominant pattern in the coronary vein. The phase opposition between arterial and venous flows was more remarkable in intramyocardial vessels, i. e., the systolic reverse flow in the artery showed a reciprocal relation to the systolic forward flow in the vein. In veins, suction of blood from superficial veins to a deeper portion may occur during diastole. The laser Doppler catheter was found to be useful for monitoring coronary vein flows in the coronary sinus and the great cardiac vein. We found that the four different routes of access of optical fiber probe are useful for the evaluation of coronary flows.