Different Prognostic Significance of High On-Treatment Platelet Reactivity as Assessed by the VerifyNow P2Y12 Assay After Coronary Stenting in Patients With and Without Acute Myocardial Infarction

Objectives This study compared the prognostic role of high on-treatment platelet reactivity (HTPR) in predicting thrombotic events in a Korean population undergoing percutaneous coronary intervention (PCI) in the acute myocardial infarction (AMI) and non-AMI setting. Background The prognostic significance and optimal cutoff of HTPR might differ according to a given clinical condition, such as AMI and ethnicity. Methods On-treatment platelet reactivity was measured with a VerifyNow P2Y12 assay (Accumetrics, San Diego, California) in 1,226 patients (824 men; age 65 +/- 10 years), including 413 AMI cases, 12 to 24 h after PCI between March 2008 and March 2010. The prevalence of cardiovascular (CV) events defined as a composite of death from CV causes, nonfatal myocardial infarction, or stent thrombosis at 1-year follow-up were compared according to HTPR between patients with and without AMI. Results The optimal cutoff for HTPR was 272 IU of the P2Y(12) reaction unit (PRU) (area under the curve: 0.708; 95% confidence interval [CI]: 0.607 to 0.809, p = 0.03), which was the upper-tertile threshold. Among AMI patients, 1-year CV events occurred more frequently in patients with versus without HTPR (n = 14 [8.8%] vs. n = 1 [0.4%], p < 0.001), whereas there was no difference in the composite endpoint on the basis of HTPR in patients without AMI (n = 7 [2.8%] vs. n = 8 [1.4%], p = 0.193). Conclusions Increased residual platelet reactivity is related to post-discharge CV events in subjects with AMI, whereas the prognostic significance of HTPR seems to be attenuated in patients with stable coronary disease after PCI. (J Am Coll Cardiol Intv 2012;5:259-67) (C) 2012 by the American College of Cardiology Foundation