Comparing High and lOw-dose asPirin With Dual anTIplatelet Therapy for Three Months Using prasUgrel and aSpirin Following Coronary Artery Bypass Grafting. (OPTIMUS-CABG Trial)

Inclusion Criteria: A. Baseline (preoperative) inclusion criteria 1. Age \>18 years 2. Primary isolated CABG patients with stable coronary artery disease (chronic coronary syndrome) planned for at least 2 grafts. Coronary artery disease will be defined as a stenosis ≥ 70% based on coronary angiography, a FFR value ≤ 0.80 or iFr value ≤0.89; a left main diameter stenosis ≥ 50%, left main IVUS MLA value ≤ 6 mm2, or equivalent OCT measurements will also be considered. 3. Ability to comply with all study procedures and follow-up procedures 4. Signed Informed Consent to participate in the study. B. Operative inclusion criteria: 1. Intraoperative graft evaluation using transit time flow measurement in all grafts, normal flow in any graft is defined as mean graft flow \> 15 mL/min with Pulsatility Index \< 5 2. Left anterior descending artery grafted with internal thoracic artery 3. No intraoperative decision for hybrid revascularization due to incomplete revascularization (Percutaneous coronary intervention (PCI) of the ungrafted vessel) 4. No endarterectomy of the grafted vessel performed 5. Patient did not have any additional unplanned procedure (Ex. LAAC, Ablation, valve intervention, aortic intervention) Exclusion Criteria: A. Baseline (preoperative) exclusion criteria: 1. Cardiogenic shock 2. Patients with recent acute coronary syndrome (ACS) (\<12 months) 3. Single vessel CABG 4. Patients with preoperative atrial fibrillation 5. Dialysis 6. Thrombocytopenia (platelet count \< 100 000 platelets/uL) 7. Anemia (Hemoglobin level \< 10 g/dL) 8. Severe liver failure Child-Pugh classification \>4 9. Known, active infections with HIV, HBV, HCV, tuberculosis 10. Active malignant disease or history of malignancy within the past 5 years 11. Indication for DAPT (e.g. recent PCI or ACS or recent stents of peripheral arteries) 12. Indication for oral anticoagulant treatment 13 Indications for the use of methotrexate at a dose of 15 mg/week or more 14\. Any contraindication for prasugrel or ASA 15. Planned additional cardiac or non-cardiac surgery within 12 months 16. Non-cardiac co-morbidity with life expectancy less than 12 months 17. History of any bleeding complications due to the use of DAPT 18. History of intracranial bleeding 19. History of gastro-intestinal bleeding 20. Pregnancy or breastfeeding 21. Lack of compliance with the use of a highly effective method of birth control 22. Planned coronary endarterectomy 23. Severe impaired renal function (eGFR \<40mL/min/1.73 m2). B. Postoperative and prior randomization exclusion criteria: 1. Perioperative cardiogenic shock 2. Intraoperative death or death prior randomization 3. Myocardial infarction within 12-24 hours following CABG or prior randomization 4. Ischemic or hemorrhagic stroke within 12-24 hours following CABG or prior randomization 5. Any postoperative complication that may increase patients' risk with DAPT 6. Atrial Fibrillation prior randomization 7. Gastro-intestinal bleeding prior randomization