Randomized clinical trial to assess the influence of treatment with ticagrelor or clopidogrel in the number of CECs (Circulating Endothelial Cells) and EPCs (Endothelial Progenitor Cells) in patients with ACS (Acute Coronary Syndrome), from baseline levels to chronic levels (1 month).

ACS Patients in both treatment groups will be assessed:

Baseline, 48h and 1 month cell counts will be done for CECs and EPCs Platelet Function at 48h and 1month Adverse Events, ECG and blood testing result will be also collected

Inclusion Criteria:

• Willing to sign Informed Consent Form
• 18 yr or older
• Male and female (post menopause or contraception treatment)
• ACS diagnosed with elevation of myocardial infarction biomarkers (as of 3rd Universal Definition of MI)
• Planned invasive strategy (coronariography performed within 72hrs after admission)

Exclusion Criteria:

• Aspirin, clopidogrel or ticagrelor allergy.
• Hemorrhagic diathesis or very high risk of bleeding.
• Current treatment with oral anticoagulants, thienopyridines or ticagrelor.
• Limited life expectancy.
• Elective surgery planned.
• High chance of not being able to complete the follow-up period.