Differential Effects of Ticagrelor With or Without Aspirin on Platelet Reactivity and Coagulation Activation: A Randomized Trial in Healthy Volunteers.

Dual antiplatelet therapy (DAPT) is standard in acute coronary heart disease but confers a bleeding risk. To compare the effects of ticagrelor-monotherapy with ticagrelor-based DAPT on hemostatic system activation, we conducted a randomized controlled trial in 44 volunteers using a loading-dose regimen and measured platelet-aggregometry triggered by adenosine diphosphate (multiple electrode aggregometry (MEA)-ADP) and arachidonic acid (MEA-AA), the vasodilator-stimulated phosphoprotein (VASP), prothrombin fragment 1.2 (f1.2), and d-Dimer. Ticagrelor-based DAPT and ticagrelor-monotherapy significantly decreased MEA-ADP (Δmean: -51.4 (-56.9; -45.8) and -46.2 (-51.7; -40.7)) and VASP (Δmean: -70.3 (-76.2; -64.4) and -69.6 (-75.5; -63.7)) at 2 hours and over 24 hours. MEA-AA was reduced significantly by both treatments (Δmean: -72.9 (-80.6; -65.3) and -25.7 (-33.3; -18.0)) at 2 hours, and stronger by ticagrelor-based DAPT over 24 hours. Both treatments decreased f1.2 (geometric mean ratio (GMR): 0.92 (0.84; 1.01) and 0.88 (0.80; 0.96)) and d-Dimer (GMR: 0.89 (0.86; 0.92) and 0.91 (0.88; 0.94)) at 2 hours and d-Dimer over 24 hours. Ticagrelor-monotherapy and ticagrelor-based DAPT comparably affect hemostatic system activation.