Redistribution of blood flow to ischemic myocardium

Redistribution of blood flow to ischemic myocardium is a physiological process and therapeutic goal rather than a single molecular target. It involves the selective increase of blood supply to regions of the heart muscle suffering from hypoxia due to coronary artery stenosis or occlusion (CV Physiology, 2023). This effect is characteristically produced by organic nitrates, which dilate large epicardial vessels and collateral channels while reducing ventricular preload; the reduction in preload lowers intramyocardial wall tension, effectively decreasing the resistance to flow in the vulnerable subendocardial layers (StatPearls, 2023). Unlike potent arteriolar dilators such as dipyridamole, which can cause 'coronary steal' by diverting blood toward well-perfused regions, effective anti-anginal therapies focus on enhancing the flow specifically to the ischemic zones (PubMed, 2042797). Consequently, this term is used in pharmacology to describe the beneficial hemodynamic outcome of various drugs acting on vascular smooth muscle receptors and signaling pathways.

Other names

Myocardial blood flow redistributionCollateral flow enhancementSubendocardial perfusion improvementImprovement of ischemic zone perfusion

Drugs promote this effect by dilating large epicardial coronary arteries and pre-existing collateral vessels without inducing significant 'steal' from the ischemic zone. Nitrates specifically reduce left ventricular end-diastolic pressure (LVEDP) through venodilation, which decreases the extravascular compressive forces on the subendocardium, thereby facilitating blood flow to oxygen-deprived tissues.