Platelet function monitoring in patients on clopidogrel

Clopidogrel is essential to prevent recurrent ischemic events in patients with acute coronary syndromes and after percutaneous coronary interventions (PCIs). However, platelet reactivity after clopidogrel treatment is not uniform, and high on-treatment platelet reactivity (HTPR) persists in approximately one third of patients receiving clopidogrel. As recent observational studies suggest that HTPR is associated with higher risk of ischemic events, including cardiovascular death, myocardial infarction and stent thrombosis, it seems rational to monitor post-clopidogrel platelet reactivity for risk assessment and to tailor anti-platelet therapy for patients with HTPR. However, routine platelet function monitoring is not recommended by current clinical guidelines. The article aims to review the available evidence on the clinical relevance of platelet function monitoring, highlighting possible reasons for the conflict between guidelines and observational studies.