What is the best approach to anticoagulation for patients with nonvalvular atrial fibrillation who also take low-dose aspirin?
The balance of benefits and harms favors direct oral anticoagulants over warfarin (Coumadin) for patients with nonvalvular atrial fibrillation who require anticoagulation and are already taking low-dose aspirin. It is worth noting that for low-risk patients with nonvalvular atrial fibrillation, aspirin alone is an option. Because these patients were largely taking aspirin as a secondary prevention for cardiovascular disease, edoxaban (Savaysa) was least likely to increase the risk of myocardial infarction. (Level of Evidence = 1a)
Many patients with atrial fibrillation have a separate indication for aspirin. This meta-analysis performed a thorough search of several databases and identified four randomized trials with a total of 21,722 patients who had nonvalvular atrial fibrillation and were taking antiplatelet therapy (most commonly low-dose aspirin) for cardiovascular prevention. Each of the studies randomized patients to receive warfarin or a direct oral anticoagulant such as edoxaban, apixaban (Eliquis), rivaroxaban (Xarelto), or dabigatran (Pradaxa). The studies had between 1.8 and 2.8 years of follow-up. The mean age of included patients was between 70 and 72 years, approximately one-third were women, and between 10% and 55% had experienced a previous stroke. After performing a random effects meta-analysis, the authors found that patients randomized to receive direct oral anticoagulants were less likely to experience a stroke or systemic embolism (hazard ratio [HR] = 0.78; 95% confidence interval [CI], 0.67 to 0.91) or vascular death (HR = 0.85; CI, 0.76 to 0.93) than those randomized to receive warfarin. There was a trend toward a higher risk of myocardial infarction in the direct oral anticoagulant group, primarily driven by the one dabigatran trial (HR = 1.2; CI, 0.97 to 1.4), but a trend toward fewer major hemorrhages with direct oral anticoagulants (HR = 0.83; CI, 0.69 to 1.01). Patients randomized to receive a direct oral anticoagulant were significantly less likely to experience intracranial hemorrhage (HR = 0.38; CI, 0.26 to 0.56). There was minimal to moderate heterogeneity for most outcomes, although the measure used (I2) is unreliable with only four studies.
Study design: Meta-analysis (randomized controlled trials)
Funding source: Foundation
Setting: Outpatient (any)
Reference: BennaghmouchNde VeerAJWMBodeKet alEfficacy and safety of the use of non-vitamin K antagonist oral anticoagulants in patients with nonvalvular atrial fibrillation and concomitant aspirin therapy: a meta-analysis of randomized trials. Circulation2018;137(11):1117–1129.