Pharmacodynamic effects of early aspirin withdrawal after percutaneous coronary intervention in patients with atrial fibrillation treated with ticagrelor or prasugrel

Dual antithrombotic therapy (DAT) without aspirin reduces bleeding compared with triple antithrombotic therapy (TAT) in patients with atrial fibrillation who have undergone percutaneous coronary intervention, without apparently increasing ischemic events. A prospective pharmacodynamic study was performed to investigate the impact of aspirin on bleeding time, platelet function and fibrin clot analysis in this population. Patients receiving TAT (<i>n</i> = 16), comprising aspirin, ticagrelor/prasugrel and a direct-acting oral anticoagulant (DOAC), were compared with those receiving DAT without aspirin (<i>n</i> = 18). Bleeding time was reduced with DAT compared with TAT (median 27.8 vs 30.0 minutes, <i>p</i> = .005). Assessed by light transmission aggregometry, median platelet aggregation was significantly increased with DAT compared with TAT in response to arachidonic acid (63 vs 3%, <i>p</i> = .002) and collagen (72 vs 37%, <i>p</i> < .001) but not 5-μmol/L adenosine diphosphate (25 vs 27%, <i>p</i> = .966) or thrombin-receptor-activating peptide (37 vs 24%, <i>p</i> = .086). VerifyNow P2Y₁₂ assay showed > 70% inhibition in all patients. Fibrin clot lysis time and maximum turbidity were similar between groups. Using P2Y₁₂ inhibitors of consistent potency, DAT improves hemostasis through sparing cyclooxygenase-1-mediated platelet activation but has a comparable effect to TAT on other pathways and fibrin clot properties. DAT with ticagrelor/prasugrel and DOAC may provide sufficient antithrombotic effect without excessive anti-hemostatic effect.