No-reflow phenomenon during percutaneous coronary intervention: Contemporary insights into mechanisms, prediction, and management.

No-reflow phenomenon remains a common and prognostically adverse complication of percutaneous coronary intervention (PCI), characterized by impaired myocardial perfusion despite restored epicardial coronary flow. It reflects multifactorial microvascular injury involving distal atherothrombotic embolization, ischemia-reperfusion-related endothelial swelling and edema, dynamic microvascular vasoconstriction, and patient-level predisposition such as diabetes or prolonged ischemia. Because no-reflow is linked to larger infarcts and worse clinical outcomes, robust pre-procedural risk stratification is crucial. Predictive assessment has shifted from angiographic markers to intracoronary imaging that identifies vulnerable plaque and embolization-prone lesions. Prevention requires an integrated pharmacologic-procedural approach tailored to lesion and patient risk. When no-reflow occurs, prompt treatment with intracoronary vasodilators, microcirculatory support, and optimized stent deployment is required. Future directions include multimodality imaging-based personalization, real-time microcirculatory physiology, and artificial intelligence assisted risk assessment. Advancing imaging-based prediction and individualized treatment may reduce no-reflow and improve PCI outcomes. This review summarizes current concepts in the pathophysiology, prediction, prevention, and management of no-reflow phenomenon, emphasizing how intracoronary imaging-based risk stratification can improve clinical outcomes.