State of the Art: Personalized Antiplatelet Therapy by Genotype and Platelet Function Testing

The platelet P2Y₁₂ receptor plays a critical role in the genesis of arterial thrombotic events. The demonstration of clopidogrel resistance and the relation of high platelet reactivity to ADP to recurrent ischemic event occurrences in patients with coronary artery disease treated with stents significantly influenced the development of potent P2Y₁₂ receptor inhibitors. A "one size fits all" strategy of clopidogrel therapy is associated with a greater risk for recurrent thrombotic events compared to uniform use of potent P2Y₁₂ receptor inhibitors which causes more bleeding. The concept of a therapeutic window for P2Y₁₂ inhibitor therapy that strikes a balance between the attenuation of thrombotic risk and bleeding has been used to personalize antiplatelet therapy. Despite the absence of a strong recommendation in the current guidelines for platelet function testing or genetic testing, the treating interventionalist must rely on the available evidence base, as summarized in this Review, to help decide whether to employ a one-size-fits-all strategy of antiplatelet therapy or one that is personalized by objective testing.