Glycoprotein VI for diagnosis of acute coronary syndrome when ECG is ambiguous

Background: The purpose of the study was to test whether an elevated surface expression of platelet collagen receptor glycoprotein VI (GPVI) is an appropriate marker for the diagnosis of the acute coronary syndrome (ACS), especially when the electrocardiogram (ECG) is ambiguous. Methods: Between 2007 to 2008, we consecutively evaluated 378 patients with ACS and ambiguous ECG on hospital admission. In all patients, GPVI surface expression was determined by flow cytometry. In addition, the myocardial necrosis markers troponin-I (Tn-I) and creatine kinase-MB (CKMB) were measured. Results: We found that in patients with ACS and unclear ECG in whom GPVI levels (mean fluorescence intensity (MFI) >= 18.6) were elevated, the relative risk for ACS was 2.6-fold enhanced. Binary logistic regression analysis revealed that an elevated platelet GPVI level is indicating an ACS independent of biomarkers of myocardial necrosis including Tn-I, creatine kinase (CK), CKMB (GPVI: p=0.011; Tn-I: p=0.180; CKMB: p=0.250; CK: p=0.127). Patients with evident T-wave inversion and/or ST-depression showed a strong association between ACS and GPVI expression. Conclusions: Platelet GPVI surface expression is enhanced in patients with ACS with unclear ECG findings and is strongly associated with myocardial ischemia. Additional to the classical markers of myocardial necrosis Tn-I and CK, GPVI is an early biomarker for the diagnosis of ACS, especially when the ECG is ambiguous. (C) 2009 Elsevier Ireland Ltd. All rights reserved.