Advances in Interventional Cardiology New Directions in Antiplatelet Therapy

Atherosclerosis is a chronic inflammatory process that is known to be the underlying cause of coronary artery disease (CAD).1 In addition to being the first step of primary hemostasis, platelets play a pivotal role in the thrombotic process that follows rupture, fissure, or erosion of an atherosclerotic plaque.2 Because atherothrombotic events are essentially platelet-driven processes, this underscores the importance of antiplatelet agents, which represent the cornerstone of treatment, particularly in the settings of patients with acute coronary syndromes (ACS) and undergoing percutaneous coronary intervention (PCI). Currently, there are 3 different classes of antiplatelet drugs that are approved for clinical use and recommended per guidelines for the treatment and prevention of ischemic events in the settings of ACS and PCI: (1) cycloxigenase-1 (COX-1) inhibitor: aspirin, (2) adenosine diphosphate (ADP) P2Y12 receptor antagonists: ticlopidine, clopidogrel, prasugrel, and ticagrelor, and (3) glycoprotein IIb/IIIa inhibitors (GPI): abciximab, eptifibatide, and tirofiban.3–6 GPIs currently are available only for parenteral administration, and therefore their use is limited only to the acute phase of treatment of ACS patients undergoing PCI. Oral antiplatelet agents, namely aspirin and P2Y12 receptor inhibitors, are recommended for prevention of ischemic events in both the acute and long-term phases of treatment. For over a decade, dual antiplatelet therapy (DAPT) with aspirin and clopidogrel has been considered the standard of care in the setting of ACS and PCI. However, a considerable number of adverse ischemic events continue to occur with this DAPT regimen, which has led to the development of newer and more potent antiplatelet agents. The objective of the present manuscript is to provide an overview on the most recent advances of currently approved antiplatelet agents in the setting of ACS and PCI, as well as on emerging agents that are in clinical development (Figure 1). Other antiplatelet drugs that are available for clinical use, such as pentoxifylline, cilostazol, and dypirimidamole, but do not have an approved indication for patients with ACS or undergoing PCI, as well as advances in anticoagulant therapy, will not be discussed.