Discordance Between VASP Phosphorylation and Platelet Aggregation in Defining High On-Clopidogrel Platelet Reactivity After ST-Segment Elevation Myocardial Infarction

To investigate potential clinical characteristics associated with discordance between platelet vasodilator-stimulated phosphoprotein phosphorylation (VASP-P) flow cytometry (FCM) assay and light transmission aggregometry (LTA) in defining high on-clopidogrel platelet reactivity (HPR) after ST-segment elevation myocardial infarction (STEMI). In this study, platelet responsiveness was measured by the above 2 methods simultaneously on day 1 and on day 6 of STEMI onset in 90 consecutive patients who underwent primary percutaneous coronary intervention. The FCM-derived platelet reactivity index and LTA-derived platelet aggregation rate were both significantly reduced after dual antiplatelet therapy on day 6. Multiple variable-adjusted logistic regression analysis revealed that smoking (odds ratio [OR]: 4.507, 95% confidence interval [CI]: 1.123-18.09, P = .034) and onset-to-admission time (per 1 hour increase, OR: 1.196, 95% CI: 1.023-1.398, P = .025) both were independent predictors for the discordance between the 2 methods. Additionally, improved correlation and concordance was observed in nonsmokers compared with smokers. Our data show that smoking and prolonged onset-to-admission time are associated with discordance between platelet VASP-P and LTA in defining HPR after STEMI, which should be considered when planning personalized antiplatelet therapy.