Dual antiplatelet therapy for coronary artery disease.

Platelets initiate the formation of a thrombus at the site of an arterial injury, and the clotting cascade is activated as the thrombus matures. After coronary stent placement, dual antiplatelet therapy (DAPT) with aspirin and ticlopidine dramatically reduces the risk of stent thrombosis, compared with anticoagulation therapy, and has become the standard of care for prevention of stent thrombosis. Clopidogrel is a second-generation thienopyridine that eliminates the serious side effects of ticlopidine, and new P2Y12 receptor blockers have emerged to overcome the limitations of clopidogrel. Current guidelines recommend DAPT with aspirin and clopidogrel for 1 month after implantation of bare-metal stents, and for 6-12 months after implantation of drug-eluting stents (DES). In patients with acute coronary syndrome (ACS), DAPT administration for 12 months was shown to be superior to aspirin alone for the prevention of recurrent events. Treatment with aspirin and new P2Y12 receptor blockers has further reduced the rate of cardiovascular death, myocardial infarction or stroke after ACS compared with aspirin and clopidogrel. Nonetheless, long-term DAPT increases the risk of major bleeding, requiring a delicate balance between anti-ischemic benefit and bleeding risk. In summary, DAPT should be maintained for at least 6-12 months after implantation of DES, and for at least 12 months after ACS, unless contraindicated.