Coronary artery stents, particularly drug-eluting stents (DES), are used in the majority of patients who undergo percutaneous coronary intervention to improve symptoms in patients with obstructive coronary artery disease. They function both to prevent abrupt closure of the stented artery soon after the procedure as well as to lower the need for repeat revascularization compared to balloon angioplasty alone (formerly referred to as percutaneous transluminal coronary angioplasty).
Stent thrombosis is an uncommon but serious complication of coronary artery stenting that often presents as death and is almost always accompanied by myocardial infarction, usually with ST-segment elevation. DAPT (DAPT; aspirin plus platelet P2Y12 receptor blocker) significantly lowers the risk of stent thrombosis. In the absence of DAPT, the period of high risk for stent thrombosis is longer with DES than bare metal stents (BMS) due to a delay in neointimal coverage with the former. The cumulative incidence of stent thrombosis appears to occur with similar frequency in patients with BMS or DES, as long as patients are treated with DAPT for the recommended duration for the particular stent.
This topic will discuss the use of antiplatelet therapy to reduce the risk of adverse outcomes related to stent thrombosis in patients with stable coronary artery disease. Other issues related to stent thrombosis, recommendations for therapy in patients with an acute coronary syndrome, and the use of antiplatelet drugs in the periprocedural period are discussed separately. (See "Coronary artery stent thrombosis: Incidence and risk factors" and "Antiplatelet agents in acute non-ST elevation acute coronary syndromes", section on 'Duration of therapy' and "Antithrombotic therapy for elective percutaneous coronary intervention: General use", section on 'Aspirin' and "Antiplatelet agents in acute ST elevation myocardial infarction", section on 'Specifics of P2Y12 use' and "Antithrombotic therapy for elective percutaneous coronary intervention: General use", section on 'P2Y12 receptor blockers'.)
DEFINITIONS OF STENT THROMBOSIS AND RESTENOSIS
After a successful procedure, coronary stents can fail to maintain vessel patency due to stent thrombosis or stent restenosis. Stent thrombosis is an abrupt thrombotic occlusion of a previously patent stent. It is a serious complication that presents as sudden death or myocardial infarction (MI) in most patients. Despite successful repeat revascularization, the six-month mortality is high. Earlier randomized clinical trials that evaluated the frequency of stent thrombosis did not use a uniform definition in their protocols, leading to difficulty in comparing the different studies. The following definitions were used in most studies and will be referred to as the historical definition :
●Events occurring within the first 30 days were considered to represent acute or subacute stent thrombosis if there was angiographic vessel occlusion, any new Q-wave MI in an area supplied by the stented vessel, and/or unexplained death from a cardiac cause.