Suboptimal early inhibition of platelets by treatment with tirofiban and implications for coronary interventions

W e have found that platelet reactivity determined with the use of flow cytometry immediately before percutaneous coronary intervention (PCI) differentiates patients at high and low risk of adverse cardiac events after the procedure.(1) Suppression of platelet aggregation by treatment with inhibitors of glycoprotein (GP) IIb/IIIa reduces the incidence of adverse cardiac events after pCI.(2-9) In the Do Tirofiban And Reo Pro Give similar Efficacy outcome Trial (TARGET), a lower 30-day incidence of the combined end point of death, myocardial infarction, and urgent target vessel revascularization was seen in patients treated with abciximab compared with those who received tirofiban.(9) The present study was designed to determine whether the difference observed reflected suboptimal inhibition of platelet aggregation during the first 2 hours after initiation of treatment with tirofiban. We focused on this interval because our previous investigation has suggested that the extent of inhibition with the 2 agents was similar 6 to 10 hours after initiation of therapy.(10).