To the Editor: The study by Dr Price and colleagues1 found that among patients with high on-treatment reactivity, measured 12 to 24 hours after PCI with drug-eluting stents, the use of high-dose vs standard-dose clopidogrel did not reduce the incidence of major adverse cardiac events.
In the hours following PCI, there is a significant increase in platelet reactivity due to procedural platelet activation, as described in the prospective Antiplatelet therapy for Reduction of Myocardial Damage during Angioplasty—Bleeding (ARMYDA-BLEEDS) study.2 Thus, measurements of platelet reactivity performed early after PCI may not reflect the baseline individual response to antiplatelet agents, and the first hours after PCI (as in GRAVITAS) may not represent the optimal time to measure platelet reactivity to determine antiplatelet therapy. In the ARMYDA–Platelet Reactivity predicts Outcome (ARMYDA-PRO) study,3 no relationship was observed between platelet reactivity during clopidogrel therapy measured at 8 and 24 hours after PCI and the risk of 30-day major adverse cardiac events. Similarly, there was a lack of correlation between enhanced response to clopidogrel, evaluated at 8 and 24 hours after coronary stenting, and in-hospital bleeding complications.2 Conversely, in the ARMYDA-PRO and ARMYDA-BLEEDS2- 3 studies, pre-intervention measurement of on-treatment platelet reactivity better predicted the risk of major adverse cardiac events for low responders and the risk of bleeding for hyperresponders.