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Half-Dose DOAC vs. Standard Antithrombotic Therapy After LAAO
Quick Takes
- There is considerable clinical interest in finding the safest and most effective antithrombotic regimen for patients with nonvalvular atrial fibrillation who are status/post Watchman left atrial appendage occlusion.
- This prospective, nonrandomized, nonblinded study compared the standard post-Watchman antithrombotic regimen to a modified regimen using indefinite half-dose DOAC therapy.
- In this study, patients who received half-dose DOAC therapy fared substantially better than patients who received the standard regimen in terms of device-related thrombosis, thromboembolic events, and bleeding events.
Study Questions:
Compared to the standard post-Watchman antithrombotic regimen, how does indefinite half-dose direct oral anticoagulation (DOAC) perform for the outcomes of device-related thrombosis, thromboembolic events, and bleeding events?
Methods:
Patients who were eligible for Watchman left atrial appendage occlusion (LAAO) were treated with either the standard antithrombotic regimen or half-dose DOAC at the discretion of the implanting physician. The standard antithrombotic regimen included a DOAC plus aspirin 81 mg for 45 days, aspirin 81 mg and clopidogrel 75 mg for 6 months, and then indefinite aspirin 81 mg monotherapy thereafter. The half-dose DOAC group received half-dose DOAC plus aspirin 81 mg daily for 45 days followed by half-dose DOAC indefinitely thereafter. The primary endpoint was a composite of the following safety and efficacy outcomes: 1) thromboembolic events (ischemic stroke, transient ischemic attack, peripheral thromboembolism); 2) device-related thrombosis; and 3) major bleeding events.
Results:
Of the 555 patients included in the analysis, 357 (64%) received standard therapy and 198 (36%) received half-dose DOAC. The two groups were well-matched in terms of risk factors for stroke and bleeding. Over slightly more than 1 year of follow-up, the composite endpoint was reached by 9.5% in the standard group and 1.0% in the half-dose DOAC group (hazard ratio, 9.8; 95% confidence interval, 2.3-40.7). Specific event incidences were as follows for standard treatment versus half-dose DOAC:
- Thromboembolic events: 3.1% vs. 0.5%
- Device-related thrombosis: 3.4% vs. 0%
- Major bleeding: 3.9% vs. 0.5%
- Intracranial bleeding: 0.6% vs. 0% (not significant [NS])
- Nonmajor bleeding: 7.0% vs. 2.0%
- Cardiovascular mortality: 2.8% vs. 2.0% (NS)
Conclusions:
In this prospective, nonrandomized, open-label study of patients status/post Watchman LAAO, patients who received indefinite half-dose DOAC fared better than patients who received the standard antithrombotic regimen with fewer thrombotic and bleeding complications over about 1 year of follow-up.
Perspective:
The difference between the half-dose DOAC and standard groups in the composite outcome is of considerable magnitude, driven by both a lower rate of bleeding and thrombotic complications in the half-dose DOAC group. These very encouraging results should be corroborated with a randomized controlled trial. If the true magnitude of the effect is as great as in this study, such a trial would require fewer than 350 subjects and, if similarly positive, would likely lead to an immediate change in medical management for post-Watchman patients in favor of half-dose DOAC therapy. The FADE-DRT trial (clinicaltrials.gov; NCT04502017) has a half-dose DOAC arm and is actively recruiting.
Clinical Topics: Anticoagulation Management, Prevention, Vascular Medicine
Keywords: Anticoagulants, Aspirin, Atrial Appendage, Brain Ischemia, Coronary Occlusion, Fibrinolytic Agents, Hemorrhage, Ischemic Attack, Transient, Ischemic Stroke, Platelet Aggregation Inhibitors, Primary Prevention, Risk Factors, Stroke, Thromboembolism, Thrombosis, Vascular Diseases
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