Personalized antiplatelet therapy: review of the latest clinical evidence.

P2Y12-ADP receptor antagonist use has been critical in the development of percutaneous coronary intervention, dramatically reducing the rate of early stent thrombosis. However, it recently was observed that a significant proportion of patients do not achieve optimal platelet reactivity inhibition after clopidogrel loading dose. The large interindividual variability in clopidogrel responsiveness is related to several factors, including the genetic polymorphism of hepatic cytochrome P450 2C19 (CYP2C19*2), which recently has been highlighted by a warning from the U.S. Food and Drug Administration. Of importance, patients exhibiting reduced clopidogrel metabolism and/or low clopidogrel responsiveness (ie, high on-treatment platelet reactivity) have an increased rate of thrombotic events after percutaneous coronary intervention. This review summarizes the current knowledge on this important clinical issue. While the future of genetic testing remains undetermined, several trials are underway to demonstrate the potential utility of platelet reactivity testing with P2Y12-ADP receptor antagonists.