Low events rate. Scarce economical resources

Aim: to verify if after the acute phase of ACS acute coronary syndrome (1-months), from 1 to 12 months the reduction of maintenance dose of prasugrel from 10 mg to 5 mg/day may reduce the bleeding events (5 mg vs 10 mg). All patients will be treated with 325 mg of aspirin followed by a maintenance dosage of 100 mg of aspirin for at least 1 year. At baseline (after 60 mg loading dose of prasugrel) and after 1 month (7 days after the randomization at 10 or 5 mg of prasugrel) all patients will undergo light transmittance aggregometry (LTA) test to evaluate residual platelet reactivity (pharmacodynamic effects).

Inclusion Criteria:

• all ACS patients treated with PCI (percutaneous coronary intervention) and dual antiplatelet therapy (DAPT: aspirin plus prasugrel).
• Informed written consent

Exclusion Criteria:

• Age < 18 years
• Active bleeding; bleeding diathesis; coagulopathy
• History of gastrointestinal or genitourinary bleeding <2 months
• Major surgery in the last 6 weeks
• History of intracranial bleeding or structural abnormalities
• Suspected aortic dissection
• Any previous TIA (transient ischemic attack)/stroke
• Administration in the week before the index event of clopidogrel, ticlopidine, prasugrel, ticagrelor, thrombolytics, bivalirudin, low-molecular weight heparin or fondaparinux .
• Known relevant hematological deviations: Hb <10 g/dl, Thrombocytopenia. <100x10^9/l
• Use of coumadin derivatives within the last 7 days
• Chronic therapy with prasugrel or ticagrelor
• Known malignancies or other comorbid conditions with life expectancy <1 year
• Known severe liver disease, severe renal failure
• Known allergy to the study medications
• Pregnancy