An experimental study of coronary artery fluid mechanics.

Preserved baboon and canine hearts were perfused using an in-vitro pulsatile flow system. Flow rate and pulsation frequency were controlled, and velocity profile measurements were made at several sites on the left epicardial coronary arteries of each heart. Velocity profiles were measured using a multi-channel, pulsed ultrasonic Doppler velocimeter, and the data were processed with a laboratory microcomputer system. Flow in the left main coronary artery appeared to be similar to descriptions of developing curved tube flow, but an unexplained oscillation of the velocity profiles was observed in this artery. Near the bifurcation of the main coronary artery into the anterior descending and the circumflex, the pattern of velocity profile skewing appeared to be determined by the angle through which the daughter vessels turned from the main and the overall curvature of the "plane" of bifurcation. Several diameters downstream from the bifurcation the flow appeared to be quasi-steady.