No-reflow phenomenon and acute myocardial ischemia. The need for further investigation.

It has been shown that localized myocardial ischemia is accompanied by microvascular changes which produce capillary obstruction when blood flow is restored. This so-called no-reflow phenomenon has been noted in the brain, kidney, dermis and, more recently, in the myocardium. Ultrastructural studies have pointed out the role of myocardial and endothelial cells swelling. It seems likely that such damage of the vascular bed may constitute the first irreversible change during ischemia and result in failure to obtain successful reperfusion of involved myocardium. It can be suggested on the basis of recent clinical and experimental observations, that this phenomenon may play a role in subendocardial necrosis associated with cardiac surgery, and in myocytolytic necrosis. In both of these conditions, the most salient features are the microcirculatory defect and the reperfusion injury following transient ischemia. Further investigations are needed to determine the basic alterations induced by no-reflow phenomenon and the value of various prophylactic and therapeutic measures.