Hemodynamic Effects of Reductions in Coronary Blood Flow Caused by Mechanical Stenosis and Platelet Aggregates Forming in Dog Coronary Arteries

Abstract

Coronary blood flow has been measured by a variety of techniques in normal vessels for over sixty years. It is only recently that attempts have been made to measure coronary blood flow in vessels which have been given mechanical stenosis. Ameroid constrictors have been used to produce gradual, but uncontrollable narrowing of coronary arteries (1). Gould et al., in open-chest dogs, developed a snare device which could be placed around the coronary artery and attached to a machinists micrometer (2). Khouri and Gregg developed a mercury-filled pneumatic device which could produce graded amounts of coronary artery stenosis in chronically instrumented dogs (3). The partial obstruction produced with these devices has been evaluated in physiologic terms by measuring the reactive hyperemic response to temporary complete occlusion, the pressure gradient across the stenosis, and the decrease in the resting coronary blood flow. These devices do not allow for fine control of the amount of stenosis or small reductions in the coronary blood flow, such as 5–10 ml/min increments. Therefore a technique is described here which produces known controlled amounts of coronary or other arterial stenosis, which can be easily altered to produce more or less stenosis, and allows for small controlled changes in coronary blood flow.