Coronary Slow Flow/No-Reflow

No-reflow is defined as failure to restore normal myocardial perfusion despite removal of mechanical obstruction in the epicardial coronary arteries. This phenomenon is associated with high risk of major adverse cardiac events, recurrent heart failure, arrhythmias, and death. The degree of reperfusion injury depends on the duration of preceding myocardial ischemia, infarct size, procedure variables, and patient characteristics. This complication predominantly occurs during percutaneous coronary intervention for acute coronary syndrome. Cardiac magnetic resonance imaging is the gold standard noninvasive method for assessing this phenomenon. Conditions such as flow-limiting dissection, in situ thrombosis, severe spasm, or high-grade residual stenosis should be excluded prior to making a diagnosis of no-reflow phenomenon. The management of no-reflow should be personalized according to the predominant mechanisms contributing to the microvascular obstruction.