Study design/study population: This trial is a prospective, open-label, single centre observational trial. Patients receive either prasugrel (60mg) or clopidogrel (600mg) at the discretion of the attending cardiologist. Patients with exclusion criteria for prasugrel will be excluded for clopidogrel as well. The study population includes 80 subjects with moderate to high-risk ACS, ie patients with unstable angina (UA) and non-ST-segment elevation MI (NSTEMI) and TIMI risk score of 3 or higher, within 72 hours after onset of symptoms. In all patients early PCI is planned.