The no-reflow phenomenon associated with percutaneous coronary intervention: Its mechanisms and treatment

In patients with acute coronary syndrome (ACS), the immediate therapeutic goal is to establish patency of the infarct-related artery and to achieve optimal myocardial tissue reperfusion. Coronary microvasculatures, however, are often damaged irreversibly due to myocardial ischemia and reperfusion, and flow to the previously ischemic myocardium is markedly reduced, a phenomenon known as the "no-reflow phenomenon". In clinical settings, percutaneous coronary intervention (PCI) may accelerate embolization of plaque gruels and microthrombi to the microvessels, which further reduces tissue perfusion. The microvascular dysfunction attenuates the beneficial impact of PCI. The extent of the no-reflow phenomenon correlates with infarct size, and it has additional prognostic information. Patients with the no-reflow phenomenon have poor functional and clinical outcomes. Recent advances in imaging modalities have enabled diagnosis of the no-reflow phenomenon and assessment of the mechanisms of the microvascular dysfunction in patients. Use of pharmacological interventions and catheter-based devices to retrieve embolic materials have been proposed, and some of them are associated with improvement in clinical outcomes. Thus, we should keep in mind that only the achievement of successful myocardial perfusion is associated with better functional and clinical outcomes in patients with ACS.