The Role of Platelet Function Testing in Risk Stratification and Clinical Decision-Making.

Clopidogrel (a widely used second-generation thienopyridine) therapy is associated with an unpredictable pharmacodynamic response whereby approximately 1 in 3 patients will have a high on-treatment platelet reactivity to adenosine diphosphate. High on-treatment platelet reactivity is an established risk factor for ischemic event occurrence in patients undergoing percutaneous coronary intervention. Platelet function testing may have a role in monitoring therapeutic efficacy when clopidogrel is the chosen agent and in safety when more potent drugs are used, especially in patients with high bleeding risk. At this time, it seems most reasonable to assess platelet function in high-risk clopidogrel-treated patients.