In a study published June 6 in the Journal of the American College of Cardiology (JACC), authors found the impact of high on-clopidogrel treatment platelet reactivity (HPR) on clinical outcomes may depend on the type of adjunct antithrombotic therapy used during percutaneous coronary intervention (PCI).

Additional Resources Full Study Trial Summary: ISAR-REACT 2 Trial Summary: GRAVITAS Trial Summary: TRIGGER-PCI Trial Summary: ADAPT-DES A Clinical Trial of Abciximab in Elective Percutaneous Coronary Intervention after Pretreatment with Clopidogrel 2011 ACCF/AHA/SCAI PCI Guidelines CardioSmart Fact Sheet: PCI

The study looked at 564 patients and found that for abciximab with unfractionated heparin (UFH), the incidence of the efficacy endpoint was similar in HPR versus no-HPR patients (9.4% vs. 6.7%; odds ratio: 1.4; p = 0.43), but 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% p < 0.0001, p for interaction= 0.037). The study is the first to specifically investigate the impact of HPR in non-ST-elevation myocardial infarction (NSTEMI) patients who either received adjunctive antithrombotic treatment with combined abciximab plus UFH or bivalirudin during the PCI procedure. It is also the first to evaluate the prognostic value of clopidogrel response testing in a large clinical trial of NSTEMI patients investigating the value of different adjunctive antithrombotic treatment options for patients undergoing urgent PCI.

Several studies have shown that responsiveness to clopidogrel treatment is not uniform and a high on-clopidogrel treatment platelet reactivity (HPR) has been linked to an increased risk for ischemic events. According to study authors, these new data show that for patients with similar risk profiles to those in the study, the effect of HPR on clinical outcomes may depend on the type of adjunctive antithrombotic therapy used during PCI. "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. Present data suggest that stronger platelet inhibition, such as provided by abciximab, is beneficial in NSTEMI patients who still have HPR after 600 mg clopidogrel loading," they note.

Moving forward, the study authors suggest that additional research is needed to clarify whether assessment of platelet function may help tailoring antithrombotic therapy during PCI.

 

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