Taking aspirin may result in an equal tradeoff between increased bleeding risk and reduced ischemic risk for up to 30 days among atrial fibrillation (AFib) patients with a recent acute coronary syndrome (ACS) and/or PCI taking either apixaban or a vitamin K antagonist (VKA), according to results of a post-hoc analysis of the AUGUSTUS trial presented March 29 at ACC.20/WCC during a Featured Clinical Research session and simultaneously published in Circulation.

In this retrospective study, John H. Alexander, MD, MHS, FACC, et al., developed three composite bleeding outcomes and three composite ischemic outcomes to look at the risk-benefit tradeoff of aspirin vs. placebo in addition to either apixaban or VKA at 30 days and at six months. The initial AUGUSTUS trial demonstrated that a placebo resulted in less bleeding vs. aspirin among AFib patients with a recent ACS and/or PCI taking a P2Y12 inhibitor and either apixaban or VKA.

The trial enrolled 4,614 patients with a median age of 71 years, all of whom were at high risk for both bleeding and ischemic events. The indication was ACS with PCI for 37% of patients, ACS treated medically in 24% and elective PCI in 39%. 

According to the results, aspirin increases severe bleeding and decreases ischemic events by about the same amount up to 30 days. At 30 days, the absolute risk for the composite bleeding outcomes ranged from 2.1% for severe bleeding to 7.5% for broad bleeding (fatal, intracranial, ISTH major, bleeding hospitalization, clinically relevant nonmajor) for patients taking aspirin vs. 1.1% for severe bleeding to 4.0% for broad bleeding in those taking the placebo. The absolute risk of an ischemic composite outcome ranged from 1.7% for severe events to 6.7% for broad events among those taking aspirin vs. 2.6% for severe events to 6.8% for broad events in the placebo group.

The same tradeoff did not continue after 30 days, the study shows. For bleeding outcomes, the absolute risk ranged from 3.7% for severe bleeding to 12.1% for broad bleeding in the aspirin group vs. 2.5% for severe bleeding and 7.2% for broad bleeding in the placebo group. The absolute risk of ischemic outcomes ranged from 3.8% for severe events to 14.3% for broad events among patients taking aspirin vs. 4.0% for severe events to 14.3% for broad events in the placebo group.

According to the researchers, the use of aspirin for up to 30 days, in addition to a P2Y12 inhibitor or oral anticoagulant, results in an equal tradeoff between an increased risk of bleeding and reduced risk of an ischemic event. Beyond 30 days, aspirin leads to an increase in bleeding without a reduction in ischemic events. The findings can help inform evidence-based decisions regarding antithrombotic therapy for AFib patients who experience an ACS and/or PCI and inform patient-centric shared decision-making, they conclude.

Clinical Topics: Acute Coronary Syndromes, Anticoagulation Management, Arrhythmias and Clinical EP, Diabetes and Cardiometabolic Disease, Dyslipidemia, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Stable Ischemic Heart Disease, Anticoagulation Management and ACS, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Interventions and ACS, Chronic Angina

Keywords: ACC Annual Scientific Session, acc20, Warfarin, Aspirin, Percutaneous Coronary Intervention, Atrial Fibrillation, Acute Coronary Syndrome, Myocardial Infarction, Stroke, Thrombosis, Stents, Angina, Stable, Arrhythmias, Cardiac, Acute Coronary Syndrome, Dyslipidemias, Heart Failure

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