Remote ischemic preconditioning inhibits platelet α_IIbβ₃ activation in coronary artery disease patients receiving dual antiplatelet therapy: A randomized trial

Objectives: We investigated whether remote ischemic preconditioning (RIPC) inhibits agonist-induced conformational activation of platelet α_IIbβ₃ in patients with coronary artery disease already receiving conventional antiplatelet therapy. Patients/Methods: Consecutive patients with angiographically confirmed coronary artery disease were randomized to RIPC or sham treatment. Venous blood was collected before and immediately after RIPC/sham. Platelet aggregometry (ADP, arachidonic acid) and whole blood platelet flow cytometry was performed for CD62P, CD63, active α_IIbβ₃ (PAC-1 binding) before and after stimulation with ADP, thrombin ± collagen, or PAR-1 thrombin receptor agonist. Results: Patients (25 RIPC, 23 sham) were well matched, 83% male, age (mean ± standard deviation) 63.3 ± 13.2 years, 95% aspirin, 81% P2Y₁₂ inhibitor. RIPC did not affect platelet aggregation, nor agonist-induced expression of CD62P, but selectively and significantly decreased α_IIbβ₃ activation after stimulation with either PAR-1 agonist peptide or the combination of thrombin + collagen, but not after ADP nor thrombin alone. The effect of RIPC on platelet α_IIbβ₃ activation was evident in patients receiving both aspirin and P2Y₁₂ inhibitor, and was not associated with an increase in vasodilator-stimulated phosphoprotein phosphorylation. Conclusions: Remote ischemic preconditioning inhibits conformational activation of platelet α_IIbβ₃ in response to exposure to thrombin and collagen in patients with coronary artery disease receiving dual antiplatelet therapy. These findings indicate agonist-specific inhibition of platelet activation by RIPC in coronary artery disease that is not obviated by the prior use of P2Y₁₂ inhibitors.