Usefulness of platelet response to clopidogrel by point-of-care testing to predict bleeding outcomes in patients undergoing percutaneous coronary intervention (from the Antiplatelet Therapy for Reduction of Myocardial Damage during Angioplasty-Bleeding Study)

Platelet reactivity predicts ischemic outcomes in patients who undergo percutaneous coronary intervention (PCI), but the correlation of heightened platelet response with bleeding has not been characterized. The aim of this study was to evaluate whether low platelet reactivity by point-of-care measurement after clopidogrel administration correlates with bleeding complications of PCI. A total of 310 patients receiving clopidogrel before PCI were prospectively enrolled. Platelet reactivity was measured with the VerifyNow P2Y12 assay. The primary end point was the 30-day incidence of major bleeding or entry-site complications according to quartile distribution of P2Y12 reaction units (PRU). The primary end point occurred more frequently in patients with preprocedural PRU levels in the lowest quartile compared to those in the highest quartile (10.1% vs 1.3%, p = 0.043), due mainly to entry-site hemorrhages. Absolute PRU levels were lower in patients with major bleeding (171 ± 49 vs 227 ± 68 in patients without, p = 0.002). On multivariate analysis, pre-PCI PRU levels in the first quartile were associated with a 4.5-fold increased risk for major bleeding (odds ratio 4.5, 95% confidence interval 1.9 to 25.9, p = 0.01). By receiver-operating characteristic curve analysis, the optimal cutoff for the primary end point was a pre-PCI PRU value ≤189 (area under the curve 0.76, 95% confidence interval 0.66 to 0.87, p = 0.001). In conclusion, this study suggests that an enhanced response to clopidogrel may be associated with higher risk for early major bleeding or entry-site complications in patients who undergo PCI. Point-of-care monitoring of platelet reactivity after clopidogrel administration may help identify patients in whom individualized strategies are indicated to limit bleeding complications after coronary intervention.