Safety and Efficacy of Ticagrelor vs Clopidogrel in Patients With Acute Coronary Syndrome

Inclusion Criteria: All-comers ACS population (with or without ST segment elevation, including unstable angina) with: A recent CCU admission (patients included in the ARIAM-CREA study within 1 week from the index ACS admission between March 1, 2015 to March 31, 2018), irrespective of either the initial management (invasive or non-invasive) or the revascularization procedure (PCI with stenting or CABG) discharged on DAPT including either Ticagrelor or Clopidogrel and have survived the first 30-day follow-up period from the index ACS event and could complete a 12-month follow-up. Exclusion Criteria: * Age \< 18 years. * Subjects who died in the first 30-day follow-up period from the index ACS event, including those who died during the index admission. * A medical condition likely to limit survival to less than 1 year. * Any factors judged by the local investigators to be likely to limit adherence to pharmacological treatment. * Failure to obtain informed consent from participant. * Currently enrolled in an interventional clinical research trial involving an investigational product (drug) or device * Not available for follow-up over a minimum of 365 days, e.g. no fixed home address. * Pregnancy, breast-feeding, or intend to become pregnant during the study period population should be always considered as exclusion criterion. * Non-ACS diagnosis at discharge, i.e., acute myocarditis, Takotsubo syndrome, pulmonary thromboembolism or acute aortic syndromes. * Myocardial infarction secondary to an ischaemic imbalance or type 2 myocardial infarction (Third Universal Definition of MI), in instances of myocardial injury with necrosis, where a condition other than CAD contributes to an imbalance between myocardial oxygen supply and/or demand, i.e., anaemia, sepsis, tachyarrhythmias, hypotension, heart failure… * Patients not discharged on dual antiplatelet therapy (DAPT) consistent on low dose of ASA plus a P2Y12platelet receptor inhibitor (Clopidogrel or Ticagrelor) * Patient discharged on DAPT including Prasugrel as the P2Y12 inhibitor drug. * Hypersensitivity to ticagrelor or any of the excipients. * Active pathological bleeding. * History of intracranial haemorrhage (ICH). * Severe hepatic impairment.