Bedside monitoring to adjust antiplatelet therapy for Coronary stenting N Engl J Med. 2012 Nov 29;367:2100-9 Prof. Soo-Joong Kim / R3 Yu Ho Lee

Introduction Aspirin, clopidogrel Platelet reactivity test Play a central role in the treatment of percutaneous coronary intervention (PCI) One third of patients have inadequate platelet inhibition Platelet reactivity test Shown prognostic value during antiplatelet therapy in patients undergoing coronary stenting Unknown whether individualized antiplatelet therapy can improve the long-term clinical outcome

Introduction ARCTIC study The Assessment by a Double Randomization of a Conventional Antiplatelet Strategy versus a Monitoring-guided Strategy for Drug-Eluting Stent Implantation and of Treatment Interruption versus Continuation One Year after Stenting Evaluated a strategy of systematic platelet-function monitoring for the purpose of adjusting treatment in patients with a poor response to aspirin, thienopyridine (clopidogrel or prasugrel) as compared with a conventional approach

Methods Study patients Inclusion criteria Randomized, open-label study 38 centers in France Inclusion criteria Patients scheduled to undergo drug-eluting stent implantation Exclusion criteria PCI for ST-segment elevation The planned use of glycoprotein IIb/IIIa inhibitors Long-term anti-coagulation therapy Bleeding diathesis

Methods Randomization and treatment strategies Monitoring group : platelet-function evaluation with adjustment of antiplatelet drugs and doses Conventional-treatment group : conventional treatment without platelet-function assessment In the monitoring group.. Platelet-function measurements were performed for aspirin, P2Y12 inhibitors Repeated measurements 2 to 4 weeks after stent implantation Platelet-function Monitoring : VerifyNow assay (Accumetrics)

Methods VerifyNow Assay

Methods Aspirin reaction unit (ARU) ARU > 550  High platelet reactivity P2Y12 reaction unit (PRU) PRU > 235 or inhibition < 15%  High platelet reactivity

Methods Before stent implantation Patients with high Aspirin reaction unit (ARU) Administration of intravenous aspirin Patients with high P2Y12 reaction unit (PRU) Administration of glycoprotein IIb/IIIa inhibitors Additional loading dose of clopidogrel (at a dose of > 600mg) or prasugrel (60mg) before the procedure Daily maintenance dose of 150mg of clopidogrel or 10mg of prasugrel after the procedure

Methods At 14 to 30 days after stent implantation Patients with high P2Y12 reaction unit (PRU) during treatment with clopidogrel Switched to prasugrel 10mg or 75mg increase in maintenance dose of clopidogrel

Methods Primary end points Main secondary efficacy end points Composite of death from any cause Myocardial infarction Stroke or transient ischemic attack (TIA) Urgent coronary revascularization Stent thrombosis Main secondary efficacy end points Composite of stent thrombosis and urgent revascularization Main safety end points Major bleeding event

Methods Statistical analysis Primary and secondary end points : Cox model for survival analysis Nongaussian variables : summarized as medians, compared with Mann-Whitney test Frequency comparison : Chi-square test

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Conclusion Our data do not support the routine use of platelet- function testing in patients undergoing coronary stenting