A point-of-care platelet function assay and C-reactive protein for prediction of major cardiovascular events after drug-eluting stent implantation.

OBJECTIVES This study sought to investigate clinical utility of on-site platelet function test and C-reactive protein (CRP) in patients undergoing percutaneous coronary intervention (PCI). BACKGROUND Data on long-term prognostic value of high on-treatment platelet reactivity (HTPR) on clopidogrel after PCI are limited. As a distinct biological pathway, CRP has been suggested to be associated with post-PCI atherothrombotic events. METHODS We evaluated 2,849 patients who received drug-eluting stents (DES) and had post-PCI VerifyNow P2Y12 assays (Accumetrics, San Diego, California) performed. Among them, baseline CRP measurement was available in 2,546 patients. The primary endpoint was a composite of all-cause death, nonfatal myocardial infarction, stent thrombosis, and stroke. RESULTS During follow-up (median, 2.2 years), the occurrence of the primary endpoint did not significantly differ among patients with and without HTPR (2.8% vs. 2.4% at 2 years; hazard ratio [HR]: 1.33, 95% confidence interval [CI]: 0.88 to 2.01; p = 0.18). By contrast, patients with elevated CRP levels were at significantly higher risk for the primary endpoint, as compared with those with nonelevated CRP levels (5.6% vs. 1.7% at 2 years; HR: 2.81, 95% CI:, 1.83 to 4.31; p < 0.001). The VerifyNow test had no incremental usefulness to classify long-term risk. However, the incorporation of CRP into a model with conventional clinical and procedural risk factors significantly improved the C-statistic for the prediction of the primary endpoint (0.729 to 0.759; p = 0.03). CONCLUSIONS We failed to identify that HTPR measured by VerifyNow P2Y12 assay was significantly associated with long-term atherothrombotic risks in patients receiving DES. However, elevated CRP levels were significantly associated with worse outcomes and had incremental predictive values over conventional risk factors.