Collateral Blood Flow

Collateral vessels can play a significant role in supplying oxygen to an organ, particularly when oxygen delivery is limited by disease in the normal vasculature. Collateral vessels can be pre-existing vessels that normally have little or no blood flow. Acute occlusion of normal vessels (e.g., thrombosis of a large artery) can cause a redistribution of pressures within the vascular bed thereby causing blood flow to occur in collateral vessels. Conditions of chronic stress (e.g., endurance exercise training or chronic hypoxia) can cause new blood vessels to form by angiogenesis.

Collateral blood vessels are particularly important in the coronary and skeletal muscle circulations. In the heart, collateral vessels can help to supply blood flow to ischemic regions due to stenosis or occlusion of epicardial arteries. Collateral blood flow may be an important mechanism in limiting infarct size in the heart. Current research is directed towards stimulating the formation of collateral blood vessels by treating the heart with drugs that stimulate angiogenesis.

RK Revised 04/06/2007