Point-of-Care Measurement of Clopidogrel Responsiveness Predicts Clinical Outcome in Patients Undergoing Percutaneous Coronary Intervention

OBJECTIVES: The aim of this study was to evaluate the correlation of point-of-care measurement of platelet inhibition with clinical outcome in patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: Individual variability of clopidogrel response might influence results of PCI. METHODS: A total of 160 patients receiving clopidogrel before PCI were prospectively enrolled. Platelet reactivity was measured by the VerifyNow P2Y12 assay (Accumetrics Inc., San Diego, California). Primary end point was 30-day occurrence of major adverse cardiac events (MACE) according to quartile distribution of P2Y12 reaction units (PRU). RESULTS: Primary end point occurred more frequently in patients with pre-procedural PRU levels in the fourth quartile versus those in the lowest quartile (20% vs. 3%; p=0.034), and it was entirely due to periprocedural myocardial infarction (MI). Mean PRU absolute levels were higher in patients with periprocedural MI (258+/-53 vs. 219+/-69 in patients without; p=0.030). On multivariable analysis pre-PCI PRU levels in the fourth quartile were associated with 6-fold increased risk of 30-day MACE (odds ratio: 6.1; 95% confidence interval: 1.1 to 18.3, p=0.033). By receiver-operating characteristic curve analysis, the optimal cut-off for the primary end point was a pre-PCI PRU value>or=240 (area under the curve: 0.69; 95% confidence interval: 0.56 to 0.81, p=0.016). CONCLUSIONS: This study indicates that high pre-PCI platelet reactivity might predict 30-day events. Use of a rapid point-of-care assay for monitoring residual platelet reactivity after clopidogrel administration might help identify patients in whom individualized antiplatelet strategies might be indicated with coronary intervention.