Adjustments in regional coronary perfusion accompanying reductions in regional coronary arterial pressure

Regional flow per unit weight has been found to be reduced under basal conditions in areas of human myocardium which are supplied by severely stenotic coronary arteries or are entirely collateral-dependent. Coronary arterial pressure within these areas is presumably reduced substantially in relation to systemic arterial pressure. In experimental animals it has recently been demonstrated that reductions in local coronary arterial pressure can result in reductions in regional myocardial flow (in all transmural layers) before vasodilator reserve is exhausted. Although the functional and metabolic accompaniments of regional flow reductions occurring in the face of vasodilator reserve remain incompletely defined, a reduction in regional metabolic demand is among the possibilities deserving consideration.