Pathophysiology, Diagnosis, and Management of Coronary No-Reflow Phenomenon

Abstract

Coronary no-reflow phenomenon is a lethal mechanism of ongoing myocardial injury, following successful revascularization of an infarct-related coronary artery. Incidence of this phenomenon is high following percutaneous intervention, and is associated with adverse in-hospital and long-term outcomes. Several mechanisms such as ischemia-reperfusion injury and distal microthromboembolism in genetically susceptible patients and those with preexisting endothelial dysfunction have been implicated. However, the exact mechanism in humans is still poorly understood. Several investigative and treatment strategies within and outside the cardiac catheterization laboratory have been proposed, but have not uniformly shown success in reducing mortality or in preventing adverse left ventricular remodeling resulting from this condition. The aim of this article is to provide a brief and concise review of the current understanding of the pathophysiology, clinical predictors, and investigations and management of coronary no-reflow phenomenon.

Keywords: angiogram; diagnosis; magnetic resonance imaging; management; no-reflow phenomenon; pathophysiology.

Fig. 1

Coronary angiographic findings in coronary no-reflow. ( A ) Patient presented with anterior myocardial infarction in the left anterior descending artery with total LAD occlusion. ( B ) Left heart catheterization with balloon angioplasty aspiration thrombectomy. ( C ) Post-percutaneous coronary intervention, there was only thrombolysis in myocardial infarction-1 flow of the LAD despite open epicardial coronary artery indicating no-reflow phenomenon.

Fig. 2

Cardiac MRI imaging showing myocardial perfusion defect and microvascular obstruction. ( A ) MRI image showing resting first pass perfusion showing total lack of perfusion in the LAD area indicated by the divided arrow. ( B ) Delayed enhancement image showing a thin rim of subepicardial delayed enhancement (white area) pointed by the two vertical arrows signifying scar and microvascular obstruction (black area indicated by divided arrow) in rest of the LAD area due to total lack of perfusion and inability of gadolinium contrast to reach this area. On cine imaging, entire LAD area was akinetic. LAD, left anterior descending; MRI, magnetic resonance imaging.

Fig. 3

Algorithm for the treatment of no-reflow phenomenon.

Fig. 4

Putative mechanisms for coronary no-reflow and suggested therapeutic targets based on pathophysiology.