OPTImal Management of Antithrombotic Agents: OPTIMA-5

This is a prospective, randomized, open-label clinical trial which will enroll 80 acute coronary syndrome (ACS) patients after Percutaneous Transluminal Coronary Intervention (PCI) in China. Patients on maintenance dosing (MD) of aspirin (100 mg/d) and ticagrelor (90 mg twice daily) will be divided into two groups switching from ongoing ticagrelor to clopidogrel 600 mg loading dose (LD)/ 75 mg MD according to their bleeding risk. Then each group will randomly switch at different times(24 hours/ 12 hours after the last MD of ticagrelor). Pharmacodynamic assessments are performed at baseline, and at 4h, 8h, 24h, 48h, 72h hours with platelet aggregation rate by Light Transmittance Aggregometry method (LTA). All patients are followed-up for 30 days.