The use of antiplatelet agents following percutaneous coronary intervention: focus on late stent thrombosis

摘要

The uptake of drug-eluting stents (DES) has been rapid since their introduction at the start of the decade, owing to their clear superiority over bare-metal stents (BMS) in reducing restenosis rates after percutaneous coronary intervention. However, with the widespread use of DES, there has been growing concern that they may also be associated with an increased risk of late stent thrombosis compared with BMS. Late stent thrombosis is a serious concern as it may lead to myocardial infarction or death. Recent analyses of clinical trials comparing the efficacy and safety of BMS and DES appear to confirm that DES may indeed be associated with a small but significant increase in the risk of late stent thrombosis and that this increased risk may continue for several years after stenting. Dual antiplatelet therapy with aspirin and clopidogrel has been shown to be effective in reducing the risk of acute/subacute stent thrombosis. On the basis of the evidence of increased risk of late stent thrombosis, guidelines now recommend extending dual antiplatelet therapy to at least 12 months after implantation of DES, and even longer in patients at high risk of stent thrombosis. Guidelines also stress the dangers of late stent thrombosis associated with premature discontinuation of antiplatelet therapy. Reduced responsiveness to clopidogrel or to aspirin is a relatively common phenomenon and may also lead to patients being inadequately protected against late stent thrombosis. New antiplatelet agents that provide significantly greater and more consistent inhibition of platelet aggregation may have benefits in reducing the risk of late stent thrombosis and the associated burden of serious adverse cardiovascular outcomes and death.