A simple model of the hemodynamic effects of a proximal coronary artery narrowing.

A simple mathematical model of the hemodynamic effects of a discrete proximal coronary artery obstruction is presented. The model demonstrates that resting myocardial flow demands fail to be met when the vessel diameter is decreased by 75% or greater. More strikingly, it shows that the maximum flow obtainable for increased myocardial oxygen demand begins to fall significantly with a lesion causing a 40 to 50% obstruction. The implications of these findings in relation to stress-induced angina are discussed.