Intravascular blood velocity in simulated coronary artery stenoses.

The profiles of blood velocity within arterial stenoses have been measured using fiber optic laser Doppler anemometry (FOLDA). The arterial stenoses were created in arteries and tubes of similar size to human coronary arteries and were perfused in vitro at pressures and flows typical of those in the human circulation. At very low flow rates, flow and peak velocity are linearly related, and thus peak velocity measurement can predict internal cross-sectional areas accurately. With higher flow rates, the intravascular velocities are not linearly related to flow and cannot be used to measure internal cross-sectional area. This is due to flattening of the velocity profile at both more severe stenoses and higher flow rates.