Continuous Clopidogrel Dose Adjustment in Acute Coronary Syndrome Patients With High On-treatment Platelet Reactivity

Effect of Continuous Clopidogrel Dosing Targeted After Platelet Function Testing in Acute Coronary Syndrome Patients Undergoing Percutaneous Coronary Intervention With High On-treatment Platelet Reactivity

The purpose of this study is to determine whether continuous clopidogrel dose adjustment targeted after platelet function testing improves outcomes during 12 months of follow-up in acute coronary syndrome patients treated with coronary artery stenting and with determined high platelet reactivity on clopidogrel.

Dual antiplatelet therapy (DAPT) with aspirin and P2Y12 receptor antagonists during 12 months presents cornerstone treatment in acute coronary syndrome (ACS) patients undergoing percutaneous coronary intervention (PCI). Clopidogrel is the most widely used P2Y12 inhibitor despite it's limitations that include highly variable P2Y12-receptor inhibition which causes wide interindividual platelet reactivity variability. Since high on-treatment platelet reactivity (HTPR) on clopidogrel is strongly associated with adverse events, antiplatelet therapy tailoring has been vastly investigated to determine whether individualized approach could improve outcomes. In the time of progressive personalized approach to therapy, effective strategies are needed to minimize the risk of ischemic adverse events without increasing the risk for bleeding.

Aim of this study is to investigate whether continuous clopidogrel dose adjustment according to platelet function testing (PFT) using Multiplate® function analyzer (Roche Diagnostics, Mannheim, Germany) could decrease the rate of adverse events in ACS patients treated with PCI and with HTPR during early and late period of DAPT treatment.

Cut off values for HTPR and enhanced platelet response were set according to the consensus statement at >46 U and <19 U, respectively. PFT and therapy tailoring was performed at day 1, 2, 3, 7, 30 and month 2, 3, 6, 9 and 12.

Inclusion Criteria:

• acute coronary syndrome patients treated with successful PCI
• age 18-80 years
• determined high on-treatment platelet reactivity

Exclusion Criteria:

• continuous postinterventional glycoprotein (GP) IIbIIIa receptor inhibitor infusion
• thrombocytopenia (<150x109/L)
• significant renal insufficiency (creatinine>200 µmol/L)
• anemia (Htc<30%)
• hemorrhagic diathesis
• history of intracranial bleeding or ischemic cerebrovascular insult 6 months before
• major operation 6 weeks before
• concomitant chronic anticoagulation therapy
• age <18 years and >80 years