Lopes RD, et al. - Researchers performed an international trial with a two-by-two factorial design in order to determine suitable antithrombotic regimens for patients with atrial fibrillation who have an acute coronary syndrome or have undergone percutaneous coronary intervention (PCI). From 33 countries, they enrolled 4,614 patients with atrial fibrillation who had an acute coronary syndrome or had undergone PCI and were planning to take a P2Y₁₂ inhibitor. Patients were randomized to receive apixaban or a vitamin K antagonist and to receive aspirin or matching placebo for 6 months. Outcomes revealed less bleeding and fewer hospitalizations when an antithrombotic regimen that included apixaban, without aspirin, was administered to these patients, without significant differences in the incidence of ischemic events, vs regimens that included a vitamin K antagonist, aspirin, or both.