Residual platelet reactivity is associated with clinical and laboratory characteristics in patients with ischemic heart disease undergoing PCI on dual antiplatelet therapy

A residual platelet reactivity (RPR) on antiplatelet therapy in patients with ischemic heart disease (IHD) has been reported to be associated with adverse clinical events by some Authors. However, scarce data are present on the clinical parameters associated with this phenomenon. No study, at our knowledge, was designed with the specific aim to examine the relationship between clinical characteristics and RPR. We sought to evaluate the clinical and laboratory characteristics associated with RPR in patients with IHD undergoing coronary revascularization on dual (aspirin plus clopidogrel) antiplatelet therapy. We included in the study 868 patients undergoing a coronary angiography: 386 with acute coronary syndromes undergoing a primary coronary revascularization and 482 IHD patients scheduled to undergo an elective coronary angiography. We measured platelet function by both platelet aggregation with two agonists [0.5 mg/mL arachidonic acid (AA); 2 and 10 microM adenosine 5'-diphosphate (ADP)] and a point-of-care assay (PFA-100) on venous blood samples collected within 24 h from the end of the procedure. In patients with acute coronary syndromes and elective PCI diabetes is independently associated with RPR [group A: OR=2.9 (1.5-5.7) by 10 microM ADP, OR=5.3 (1.1-27.8) by PFA-100; group B: OR=4.0 (1.6-10.0) by 10 microM ADP]; reduced left ventricular systolic function [OR=3.7 (2.2-6.5) by AA-PA, OR=2.7 (1.6-4.6) by PFA-100], chronic use of aspirin [OR=0.2 (0.1-0.4) by AA-PA, OR=0.3 (0.2-0.5) by PFA-100] and loading dose of clopidogrel [OR=0.2 (0.06-0.5) by 10 microM ADP] were independent variables significantly associated with RPR in patients undergoing elective PCI. In addition, inflammatory status was found to be significantly associated with RPR in both groups of patients. These results provide indications for the selection of patients for whom the evaluation of platelet reactivity could be useful.