Platelet reactivity after ASA and clopidogrel treatment assessed with VerifyNow point-of care analysis in patients with stable coronary artery disease undergoing percutaneous coronary intervention

Aims: The aim of this prospective trial was to assess whether platelet reactivity (PR) to clopidogrel and aspirin (ASA) correlates with biological variables and predicts myonecrosis following PCI in patients with stable angina pectoris, with or without diabetes. Assessment of PR using VerifyNow® point of care analysis has shown to detect patients at risk for stent thrombosis and has been proposed to guide antiplatelet therapy. Methods and results: Between April 2008 and December 2009, 686 patients with stable angina and planned PCI with stent implantation were evaluated with the VerifyNow® to determine PR before PCI. All patients received a single 600 mg clopidogrel loading dose and 500 mg ASA 12 hours before the procedure. PR was assessed in diabetic (n=173) and non-diabetic patients (n=513) and compared with demographic, biological and procedural data. Troponine elevation obtained following PCI was compared with PR. Results for diabetics and non-diabetics are per quartiles for clopidogrel platelet reactivity, aspirin platelet reactivity, C-Reactive Protein, creatinine, hemoglobin, hemoglobin A1C, body mass index and troponin (Tn) post-PCI. Response to aspirin is homogeneous, while response to clopidogrel shows wide inter-individual variation. Conclusions: 1)Platelet inhibition by ASA is predictable and similar in diabetic and non-diabetic patients. 2)Platelet reactivity after clopidogrel treatment is highly variable and lower among diabetic patients. 3)Neither HbA1c, creatinine, uCRP, Hb level or BMI affect antiplatelet activity of clopidogrel . 4)Low platelet reactivity assessed with point of care VerifNow® is not associated with an increased elevation of Tn post PCI among patients with stable angina.