Profiles of velocity in coronary arteries of dogs indicate lower shear rate along inner arterial curvature.

Multiple-range, gate-pulsed Doppler velocimetry was used to examine the velocity profile within the lumen of the left circumflex and left anterior descending coronary arteries of 10 anesthetized, open-chest dogs at rest and after administration of propranolol and intracoronary adenosine. The peak diastolic and mean profiles of velocity were skewed away from the inner walls of the vessels (p less than 0.01). The extent of skewness was not affected by propranolol or adenosine. The shear rates were significantly lower along the inner wall in comparison to the outer wall under all conditions in both the left circumflex and the left anterior descending coronary arteries (p less than 0.017). Irrespective of the levels of flow, therefore, the velocity profiles were skewed away from the inner wall of the coronary arteries. Consequently, the shear rates were lower along the inner walls of the coronary arteries.