The coronary no-reflow phenomenon: a review of mechanisms and therapies

The phenomenon of no-reflow is defined as inadequate myocardial perfusion through a given segment of the coronary circulation without angiographic evidence of mechanical vessel obstruction. Temporary occlusion of the artery, a prerequisite condition for no-reflow, may be produced in the experimental setting or occur during reperfusion of an infarct-related artery or following percutaneous coronary intervention. No re-flow implies abnormal tissue perfusion and persistent no-reflow is associated with higher clinical complication rates. The concept of coronary no-reflow was first described in experimental models in 1966 and then in the clinical setting of reperfusion after myocardial infarction in 1985. Although often debated by fundamentalists, the term no-reflow was used to describe the same phenomenon in the field of interventional cardiology in 1989. No-reflow has been documented in 30% of patients after thrombolysis or mechanical intervention for acute myocardial infarction. Compared to similar patients with adequate reflow, those with no-reflow have more congestive heart failure early after myocardial infarction and demonstrate progressive left ventricular cavity dilatation in the convalescent stage of the infarction. During coronary intervention, no-reflow has been reported in 0·6% to 2% of cases and has been identified with treatment of saphenous vein grafts, atherectomy, and PTCA and stenting of thrombus containing lesions. Persistent no-reflow has been associated with increased mortality and a high incidence of myocardial infarction.