To manage the ST-segment elevation myocardial infarction (STEMI) caused by plaque rupture, triggers platelet activation/aggregation and thrombin generation, requires dual (platelet and coagulation) pathway inhibition. However, triple antithrombotic therapy with standard dual antiplatelet therapy (DAPT) and oral anticoagulant (OAC) in the STEMI setting is a challenge, since that increase in potential risk of bleeding. Although the incidence of left ventricular thrombus (LVT) formation after STEMI decreased in modern reperfusion therapy, including primary percutaneous coronary intervention (PCI), remains at 4% to 26%, especially that complicated by anterior STEMI. The recommendation of an OAC prophylactic therapy for preventing LVT formation in current STEMI guidelines is limited. How to optimize antithrombotic therapy to balance the bleeding-thrombotic profile, and prevent LVT formation is challenging, since insufficient evidence is available from randomized trials. Century Clot analyzer is point-of-care testing that could assess the coagulate state: normal, hypo-coagulable, or hyper-coagulable states according to clot rate (CR) value. Whether Century Clot-guided rivaroxaban prophylactic therapy (2.5 mg twice daily, if the hypercoagulable state, defined as CR ≥24) in combination with standard DAPT could reduce LVT formation without increasing major bleeding is uncertain.