[Late stent thrombosis after drug-eluting stent implantation: epidemiological, clinical and pathophysiological aspects]

Abstract

Stent thrombosis (ST) is an uncommon, but potentially catastrophic, complication of percutaneous coronary intervention, since it can be associated with acute myocardial infarction and death. The advent of drug-eluting stents (DES) has raised concerns regarding numerous reports about very-late occurrences of ST. Data from the literature seem to suggest an increased incidence of ST in patients treated with DES vs bare-metal stents after the first year from percutaneous coronary intervention (very-late ST). The magnitude of this phenomenon is quite modest in absolutely value (between 0.35% and 0.6% per year) and it does not translate into a worse hard outcome (death and myocardial infarction) for patients treated with DES vs bare-metal stents. ST is a multifactorial process, linked to many causes, each of which may play a different role in early, late or very-late ST. In the development of early ST procedural factors, antiplatelet response/compliance and lesion complexity are of primary importance; patient's risk factors, delayed endothelialization and healing of the arterial wall are involved in the late and very-late ST. Nowadays appropriate selection of DES candidates, technically accurate implantation procedures, and adequate instructions to the patient for increasing therapy compliance are the basis for the reduction of the risk of ST; the identification of more effective antiplatelet drugs and new-generation DES (i.e., bioabsorbable polymers or stents) are promising innovations for the future.