INTRODUCTION
Atrial fibrillation (AF) is a common supraventricular tachyarrhythmia caused by uncoordinated atrial activation and associated with an irregularly irregular ventricular response 1-4. The causes of AF include underlying structural heart disease, metabolic disorders, endocrine diseases, and certain medications1-4. The prevalence of AF is approximately 1%-2% in the general population in developed countries 1-6. Patients with AF are often at a significantly increased risk of thromboembolism and, in particular, stroke 1-4. Most patients with atrial fibrillation are at increased risk of stroke and should receive thromboembolic prophylaxis in order to lower that risk1-4. The risk of thromboembolism can be significantly reduced by appropriate use of antithrombotic therapy but at a somewhat increased risk of bleeding 1-4.
Left atrial appendage closure (LAAC) has emerged as a valid non-pharmacological option for the prevention of stroke in patients with nonvalvular AF and contraindications to an indefinite oral anticoagulation (OAC) therapy 2. Post-procedural antithrombotic therapy is usually administered to prevent device-related thrombi (DRT) and subsequent thromboembolic events until device endothelialization 7. Nevertheless, each regimen carries a certain risk of bleeding complications. The optimal drug regimen and duration following LAAC with the Watchman occluder (Boston Scientific, Marlborough, MA, US) is still under investigation. As a consequence, various post-procedural anticoagulation strategies are adopted among centers 7, 8.
In the randomized PROTECT-AF and PREVAIL trials, the patients received a vitamin K antagonist (VKA) plus aspirin for 45 days, followed by dual antiplatelet therapy (DAPT) for 4.5 months in patients eligible for OAC after Watchman LACC 9, 10. Subsequent studies showed that DAPT for variable durations was an effective and safe alternative to warfarin after Watchman implantation in large real-world registries11, 12. A single-center registry reported the feasibility of a shortened 6-week DAPT 13. In the multicenter EWOLUTION registry, patients on non-vitamin K oral anticoagulants (NOACs) had the lowest bleeding rate, without an increase in DRT or stroke rates 14. Nevertheless, the most optimal strategy remains to be defined.
This post hoc analysis of a dual-center prospective observational study examined the incidence rates of non-procedure-related complications including death, thromboembolic events, and bleeding events in patients who received a 3-month DAPT regimen vs. 6-week anticoagulation plus aspirin followed by a 4.5-month DAPT (ACT regimen) over a 12-month follow-up period after successful LAAC. In addition, the associated risk factors for net clinical benefit and clinically relevant bleedings were examined.