A 62-year-old man presents to a metropolitan emergency department with 2 hours of central chest pain radiating to the left arm. ECG shows 1-2 mm ST depression in leads V4-V6 and troponin I is elevated. He has no history of bleeding, stroke or anticoagulant use. Coronary angiography is planned within 24 hours. According to Australian acute coronary syndrome management, what is the most appropriate immediate antiplatelet strategy?