Summary
Background
Dual antiplatelet therapy with a P2Y12 inhibitor and aspirin is standard in acute coronary syndromes. Dual antiplatelet therapy causes more bleeding than single antiplatelet therapy with a P2Y12 inhibitor.
Objectives
To compare the effects of dual and single antiplatelet therapies on hemostatic system activation.
Patients/Methods
In a randomized, parallel‐group, double‐blind, placebo‐controlled study, 44 healthy volunteers received clopidogrel (600 mg, then 150 mg d–1) and aspirin (100 mg d–1) or placebo for 7 days; An additional 44 volunteers received single‐dose ticagrelor (180 mg) and aspirin (300 mg) or placebo. β‐Thromboglobulin (β‐TG [IU L–1]) and prothrombin fragment 1.2 (f1.2 [nmol L–1]) were measured in blood obtained from bleeding time incisions. Data are given as geometric mean ratio (GMR [95% confidence interval]) to describe the differences in the first 2 h and as mean differences (Δ [95% confidence interval]) in area under the curve (AUC) to discriminate differences in effects over the total observation time.
Results
Clopidogrel plus aspirin and clopidogrel plus placebo reduced β‐TG by a GMR of 0.51 (0.42–0.63) and 0.54 (0.46–0.64) at 2 h. Ticagrelor plus aspirin and ticagrelor plus placebo decreased β‐TG by a GMR of 0.38 (0.26–0.57) and 0.47 (0.31–0.72). Ticagrelor plus aspirin and ticagrelor plus placebo reduced f1.2 by a GMR of 0.58 (0.45–0.75) and 0.55 (0.38–0.80); clopidogrel did not. Over 24 h, no difference in β‐TG occurred between clopidogrel plus aspirin and clopidogrel plus placebo (ΔAUC = −2.9 [−9.9 to 4.1]) or between ticagrelor plus aspirin and ticagrelor plus placebo (ΔAUC = −3.5 [−11.8 to 4.7]). No difference in f1.2 occurred between clopidogrel plus aspirin and clopidogrel plus placebo (ΔAUC = −4.2 [−10.2 to 1.8]) or between ticagrelor plus aspirin and ticagrelor plus placebo (ΔAUC = −3.6 [−10.9 to 3.7]).
Conclusions
P2Y12 inhibitor monotherapy and dual antiplatelet therapy inhibit hemostatic system activation to a comparable extent.