Stent thrombosis: an updated clinical overview from epidemiology to classification and management.

Coronary stent implantation has revolutionised percutaneous coronary intervention (PCI), preventing vessel closure and reducing restenosis. Nonetheless, the permanent presence of an intracoronary endoprosthesis introduces two intrinsic major limitations: restenosis and stent thrombosis (ST). Although ST incidence has declined with last-generation drug-eluting stents, improved implantation technique and antiplatelet regimens, it remains a catastrophic event, typically presenting as ST-elevation myocardial infarction or sudden cardiac death, with persistently high early and late mortality. Standardised definitions classify ST by diagnostic certainty and timing from implantation, reflecting distinct underlying mechanisms across intraprocedural, early, late and very late phases. Early ST is most often driven by correctable procedural and pharmacological determinants, including underexpansion and malapposition, high thrombotic burden in acute coronary syndromes and premature discontinuation or inadequate effect, of dual antiplatelet therapy (DAPT). Late and very late ST are frequently related to delayed healing with uncovered struts, late-acquired malapposition and intrastent neoatherosclerosis or may involve hypersensitivity to stent components or allergy to external factors (Kounis syndrome type III). Intravascular imaging, particularly optical coherence tomography, complemented by intravascular ultrasound, is pivotal to identify the dominant mechanism and guide targeted therapy. Acute management relies on rapid reperfusion with PCI, mechanical optimisation and potent antithrombotic strategies; drug-coated balloon angioplasty is emerging as a mechanistically attractive option in selected late presentations to avoid additional metal. Prevention relies on imaging-guided implantation, individualised DAPT and strict risk-factor control. This narrative review summarises current definitions, epidemiology, mechanisms, diagnostic pathways and contemporary therapeutic and preventive strategies, integrating recent consensus recommendations.