Abstract 4308: Clopidogrel Response Status Assessed With Multiplate Point-of-Care Analysis and the Incidence and Timing of Stent Thrombosis Over 6 Months Following Coronary Stenting
Introduction: Clopidogrel low response assessed with multiple electrode platelet aggregometry (MEA) has been shown to be a strong and independent predictor of early stent thrombosis (ST) after coronary stenting. The relation of clopidogrel response status, as assessed with MEA, with incidence and timing of ST during an extended follow-up period has never been reported. Here, we report the 6-month follow-up results of a prospective trial assessing clopidogrel response with MEA in patients undergoing percutaneous coronary intervention (PCI).
Methods: Patients (n=1,608) undergoing PCI were enrolled in this study. Before PCI patients received 600 mg clopidogrel and blood was taken directly before PCI to measure ADP-induced platelet aggregation (in AU*min) with MEA on a Multiplate analyzer.
Results: The upper quintile of patients according to MEA measurements (n=323) were defined as clopidogrel low responders (cut-off value=416 AU*min). Compared with normal responders (n=1,285), the 6-month incidence of definite ST was significantly higher in low responders [2.5% vs. 0.4%; OR 6.5; 95% CI, 2.4 –17.0; P<0.001]. The combined incidence of definite/probable ST was higher as well in low vs. normal responders [4.1% vs. 0.7%; OR 5.8; 95% CI, 2.8 –12.3; P<0.0001; Fig. 1A]. A significant inverse correlation of MEA values and the timing of definite or probable ST (in days) was observed (Fig. 1B) with events occurring earlier in the low responders.
Conclusions: MEA measurements are highly predictive for the occurrence of ST during the first 6 months following PCI. In the majority of clopidogrel low responders suffering ST, the ischemic event occurs early in the course after the procedure.