Rationale: Dual antiplatelet therapy, consisting of aspirin and a P2Y12-inhibitor, reduces the risk of stent thrombosis, myocardial infarction and stroke after coronary stent implantation. Inevitably, it is also associated with a higher risk of (major) bleeding. Given the advances in stent properties, stenting implantation technique and pharmacology, it may be possible to treat patients with a single antiplatelet strategy by completely omitting aspirin.

Objective: This study will assess whether omitting aspirin reduces the rate of major or minor bleeding while remaining non-inferior to the current standard of care with regards to ischemic events in patients with non-ST segment elevation acute coronary syndrome.

Study design: Open-label, multicentre randomized controlled trial.

Study population: Adult patients presenting with non-ST segment elevation acute coronary syndrome undergoing percutaneous coronary intervention.

Intervention: In the intervention group aspirin will be completely omitted from the antiplatelet regimen in the 12 months following PCI.

Main study endpoints: The primary bleeding endpoint is major or minor bleeding defined as Bleeding Academic Research Consortium type 2, 3 or 5 bleeding at 12 months. The primary ischemic endpoint is ischemic events defined as the composite of all-cause death, myocardial infarction and stroke at 12 months.

Inclusion Criteria:

• Clinical diagnosis of NSTE-ACS (i.e. NSTEMI or unstable angina)
• Successful PCI (according to the treating physician)

Exclusion Criteria:

• Known allergy or contraindication for aspirin or all commercially available P2Y12-inhibitors (i.e. ticagrelor, prasugrel and clopidogrel)
• Concurrent use of oral anticoagulants (e.g. because of atrial fibrillation)
• Ongoing indication for DAPT at admission (e.g. due to recent PCI or ACS)
• Planned surgical intervention within 12 months of PCI
• Pregnant or breastfeeding women at time of enrolment
• Participation in another trial with an investigational drug or device