In the TRial to assess Improvement in Therapeutic Outcomes by optimizing platelet inhibitioN with prasugrel Thrombolysis In Myocardial Infarction 38 ( TRITON-TIMI 38 ) , prasugrel reduced the primary ischaemic endpoint as compared with clopidogrel in acute coronary syndrome ( ACS ) patients planned to undergo percutaneous coronary interventions , but increased the risk of bleeding .