Prognostic Value of a High On-Clopidogrel Treatment Platelet Reactivity in Bivalirudin Versus Abciximab Treated Non–ST-Segment Elevation Myocardial Infarction Patients: ISAR-REACT-4 (Intracoronary Stenting and Antithrombotic Regimen: Rapid Early Action for Coronary Treatment-4) Platelet Substudy

Study Questions:

What is the relevance of high on-clopidogrel treatment platelet reactivity (HPR) in non–ST-segment elevation myocardial infarction (NSTEMI) patients that received abciximab with unfractionated heparin (UFH) or bivalirudin during percutaneous coronary intervention (PCI)?

Methods:

A total of 564 patients (274 in the abciximab/UFH group vs. 290 in the bivalirudin group) were enrolled in this study. Presence or absence of HPR following clopidogrel loading was determined by platelet function testing on a Multiplate analyzer (Verum Diagnostica, Munich, Germany). Per study group and stratified in HPR and no-HPR patients, the 30-day incidence of a combined efficacy endpoint (death, myocardial infarction, urgent target vessel revascularization) was determined. Kaplan-Meier curves were plotted to illustrate the cumulative incidence of the combined efficacy endpoint per study group and with regard to presence or absence of HPR.

Results:

For abciximab with UFH, the incidence of the efficacy endpoint was similar in HPR versus no-HPR patients (9.4% vs. 6.7%; odds ratio, 1.4; 95% confidence interval, 0.6-3.5; p = 0.43). For bivalirudin, the incidence of the efficacy endpoint was significantly higher in HPR versus no-HPR patients (22.0% vs. 5.0%; odds ratio, 5.4; 95% confidence interval, 2.4-12.1; p < 0.0001).

Conclusions:

The authors concluded that the impact of HPR on clinical outcomes may depend on the type of adjunctive antithrombotic therapy used during PCI.

Perspective:

This study suggests that the prognostic value of HPR determined by periprocedural platelet function testing for predicting ischemic events in NSTEMI patients may depend on the adjunctive antithrombotic agent administered. Whereas the presence of HPR in bivalirudin-treated patients was relevant and predictive for the occurrence of early ischemic events, presence of HPR in abciximab with UFH-treated patients had little relevance in this regard. Given the post-hoc nature of this analysis, further investigations are warranted to clarify whether assessment of platelet function may help tailoring antithrombotic therapy during PCI.

Clinical Topics: Anticoagulation Management, Invasive Cardiovascular Angiography and Intervention

Keywords: Myocardial Infarction, Platelet Function Tests, Heparin, Germany, Percutaneous Coronary Intervention


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