The evolution of antiplatelet therapy in cardiovascular disease.

The platelet--an anucleate cell--is the bedrock of thrombosis, both physiologically and pathologically. Antagonism of the P2Y(12) receptor for ADP is one of several pathways inhibiting the activation and aggregation of platelets, thereby attenuating coronary thrombosis in response to spontaneous plaque rupture or percutaneous revascularization. The addition of clopidogrel to a background of aspirin therapy was a revolutionary change in the management of ischemic coronary syndromes. Despite this paradigm shift, clopidogrel has certain limitations, including variability in platelet inhibitory effect, which is associated with adverse thrombotic events. In the evolution of antiplatelet treatment strategies, two new P2Y(12) receptor antagonists--prasugrel and ticagrelor--have been added to the armamentarium in the past few years. Both of these drugs confer greater platelet inhibition than clopidogrel. Nevertheless, more-potent platelet inhibition comes with an increased risk of hemorrhagic complications. Cangrelor and elinogrel are novel P2Y(12) inhibitors that show potential in the periprocedural setting with their rapid onset and offset of activity. Successes in P2Y(12) inhibitory therapies have reduced use of glycoprotein IIb/IIIa inhibitors, which block the final pathway leading to platelet aggregation and thrombosis. Newer therapies aimed at various molecular factors are under clinical investigation. Pharmacodynamic platelet function assays and pharmacogenetic testing to individualize and optimize antiplatelet therapy may find their way into clinical use, although much more study is needed.