The significance of coronary collateral circulation in the preservation of myocardial function

Abstract

After occlusion or subocclusion of the blood vessels, myocardial perfusion is maintained through the collateral vessels. There are two mechanisms of vessel formation: arteriogenesis and angiogenesis. The term arteriogenesis describes the growth of the existing collaterals into mature arteries. On the other hand, angiogenesis, is a process of developing new blood vessels from the preexisting ones. Collateral blood vessels have many functional roles. If they are adequately developed, they can protect the myocardium from ischemic injury. Even when a total occlusion develops, regional left ventricular motility is better in segments with developed collateral circulation. In patients with well-developed collaterals, who experience coronary artery occlusion, often there is no evidence of myocardial infarction in the area of the occluded artery. Well-developed collaterals reduce the risk of unstable cardiac events. A case of right coronary artery occlusion with good collateral circulation and preserved myocardial left ventricular motility is presented. After coronary stent implantation, the patient was asymptomatic, and the maximal stress test for myocardial ischemia was negative. Despite coronary vessel occlusion, collateral blood flow maintains the pump function of the left ventricle.