Echo Predictors of Stroke in AF on Apixaban or Warfarin

Study Questions:

What is the relationship between echocardiographic findings (spontaneous echo contrast [SEC], left atrial/left atrial appendage [LA/LAA] thrombus, and complex aortic plaque) and clinical outcomes among patients with atrial fibrillation receiving oral anticoagulation; and what is the comparative efficacy and safety of apixaban and warfarin for each finding?


Data from the ARISTOTLE trial (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation; CHADS2 score ≥1) were used in a secondary post hoc analysis. Patients with SEC, LA/LAA thrombus, or complex aortic plaque diagnosed by either transthoracic (TTE) or transesophageal echocardiography (TEE) were compared to patients with none of these findings on TEE.


A total of 1,251 patients were included: 217 had SEC, 127 had LA/LAA thrombus, 241 had complex aortic plaque, and 746 had none. The rates of stroke/systemic embolism were not significantly different among patients with and without these echocardiographic findings (hazard ratio [HR], 0.96; 95% confidence interval [CI], 0.25-3.60 for SEC; HR, 1.27; 95% CI, 0.23–6.86 for LA/LAA thrombus; HR, 2.21; 95% CI, 0.71–6.85 for complex aortic plaque). Rates of ischemic stroke, myocardial infarction, cardiovascular death, and all-cause death also were not different between patients with and without these findings. For patients with either SEC or aortic plaque, there was no evidence of a differential effect of apixaban over warfarin. For patients with LA/LAA thrombus, there was also no significant interaction, with the exception of all-cause death and any bleeding, where there was a greater benefit with apixaban compared to warfarin among patients with no LA/LAA thrombus.


In anticoagulated patients with atrial fibrillation and ≥1 risk factor for stroke, echocardiographic findings do not seem to add to the risk of thromboembolic events.


In post hoc analysis of data from the ARISTOTLE trial, the authors found that the presence of spontaneous echo contrast, LA or LAA thrombus, or complex aortic plaque did not confer additional risk of stroke among anticoagulated patients with atrial fibrillation and CHADS2 score ≥1. It is possible that the relatively small number of patients with each echocardiographic finding did not allow detection of a small associated risk. Alternatively, the use of effective anticoagulation may sufficiently reduce risk among all patients (regardless of echo findings), and the absence of echo findings might not in reality define a ‘lower-risk’ group.

Clinical Topics: Anticoagulation Management, Arrhythmias and Clinical EP, Noninvasive Imaging, Prevention, Anticoagulation Management and Atrial Fibrillation, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Echocardiography/Ultrasound

Keywords: Anticoagulants, Arrhythmias, Cardiac, Atrial Appendage, Atrial Fibrillation, Diagnostic Imaging, Echocardiography, Echocardiography, Transesophageal, Embolism, Myocardial Infarction, Plaque, Atherosclerotic, Primary Prevention, Risk Factors, Stroke, Thromboembolism, Thrombosis, Warfarin

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