Trombosi tardiva dopo impianto di stent medicato: aspetti epidemiologici, clinici e fisiopatologici

Drug-eluting stents; Late thrombosis; Percutaneous coronary intervention; Stent thrombosis. 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 ad- vent of drug-eluting stents (DES) has raised concerns regarding numerous reports about very-late oc- currences 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 pa- tients 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 re- sponse/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 proce- dures, 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. (G Ital Cardiol 2008; 9 (10): 674-683)