Should Platelet Function Testing Guide Antiplatelet Therapy for Patients with Coronary Artery Stenting or Acute Coronary Syndromes?

Abstract

Inhibition of platelet activation (“antiplatelet therapy”) with platelet P2Y12 (ADP) receptor antagonists (i.e., thienopyridines such as clopidogrel and prasugrel) reduces platelet-rich thrombi that cause coronary artery stent thrombosis and recurrent acute coronary syndrome (ACS)3 (i.e., unstable angina pectoris and myocardial infarction). However, several reports suggest that there are large interindividual variations in platelet inhibition by clopidogrel, with up to one-third of patients having apparently “high platelet reactivity” while on therapy; these patients may be at increased risk for stent thrombosis and recurrent ACS (1). Consequently, platelet function testing may identify patients in whom adjustment of thienopyridine therapy is warranted to minimize the risk of both ischemic and bleeding complications. The introduction of point-of-care devices has made it possible to consider the routine evaluation of on-treatment platelet reactivity in patients undergoing coronary stenting and in ACS patients. Platelet function testing has been used in the research setting to individualize dosing of thienopyridine therapy in patients undergoing percutaneous intervention (PCI) with or without stent placement and in ACS patients (1). Several platelet function assays are available, including light transmission aggregometry (LTA), vasodilator-stimulated …