The general purpose of the Neomindset trial is to evaluate the non-inferiority hypothesis for ischemic events and the superiority hypothesis for bleeding events resulting from platelet P2Y12 receptor inhibitors given as monotherapy in comparison with conventional dual antiplatelet therapy in acute coronary syndrome patients treated with percutaneous coronary intervention.

The platelet sub-study will be conducted at the Hospital Israelita Albert Einstein. This sub-study will recruit randomized patients from the Neomindset trial to evaluate platelet function after at least 30 days of study treatment with either P2Y12 inhibitor monotherapy or dual antiplatelet therapy.

The platelet sub-study will be conducted at the Hospital Israelita Albert Einstein. This sub-study will recruit randomized patients from the Neomindset trial to evaluate platelet function after at least 30 days of study treatment with either P2Y12 inhibitor monotherapy or dual antiplatelet therapy.

These patients will undergo blood sampling and measurement of platelet function after being treated with P2Y12 inhibitor monotherapy or dual antiplatelet therapy for at least 30 days.

Inclusion criteria:

• Age >=18 years;
• Clinical presentation compatible with acute coronary syndrome with onset < 24 hours before admission;
• Successful percutaneous coronary intervention(s) of all target lesions (culprit and non-culprit) with new-generation drug-eluting stents;
• Length of stay in hospital at randomization < 96 hours;
• Subjects will be informed about the nature of the study and must agree to comply and give an informed consent in writing using a form approved in advance by the local Ethics Committee.

Exclusion Criteria:

• Acute coronary syndrome on index admission treated in a conservative way or by unsuccessful percutaneous intervention or surgically;
• Presence of residual lesions which are likely to require future treatment in the next 12 months;
• Fibrinolytic therapy < 24 hour before randomization;
• Need of oral anticoagulation with warfarin or new anticoagulants;
• Chronic bleeding diathesis;
• Active or recent major bleeding (in-hospital);
• Prior intracranial hemorrhage;
• Ischemic cerebrovascular accident < 30 days;
• Presence of brain arteriovenous malformation;
• Index event of non-atherothrombotic etiology (i.e., stent thrombosis, coronary embolism, spontaneous coronary artery dissection, myocardial ischemia due to supply/demand imbalance);
• Potential or scheduled cardiac or non-cardiac surgery in the next 12 months;
• Platelet count < 100,000 cells/mm3 or > 700,000 cells/mm3;
• Total white blood count < 3,000 cells/mm3;
• Suspected or documented active liver disease (including laboratory evidence of hepatitis B or C);
• Receiver of heart transplant;
• Known allergies or intolerance of acetylsalicylic acid, clopidogrel, ticlopidine, ticagrelor, prasugrel, heparin or antiproliferative agents from the limus-family of drugs;
• Subject with life expectation lower than 1 year;
• Any significant medical condition that, in the investigator's opinion, could interfere with the ideal participation of the subject in the study;
• Participation in other study in the past 12 months, unless a direct benefit to the subject can be expected.
• Impossibility of being treated with dual antiplatelet therapy for 12 months, based on investigator judgement.