Aims: Evidence regarding post-procedural antithrombotic therapy following percutaneous left atrial appendage (LAA) closure other than used in randomized trials is still limited. In the present study anticoagulation (AC) was compared against antiplatelet therapy (APT) using data from the German multi-centre LAARGE registry.

Methods: Patients undergoing LAA closure with an endocardial device were included into the present analysis. They were assigned to two groups depending on the post-implantation antithrombotic regime consisting either of AC or APT.  Primary outcome measure was the composite of death, stroke and systemic embolism. Secondary outcome measures were major, moderate and any bleeding.

Results: From July 2014 until January 2016 a total of 627 patients at 38 centers were included. After discharge, a total of 75 patients (12%) received AC and 552 patients (88%) received APT, mainly consisting of DAPT (97%), respectively. No significant differences were found between the groups regarding the composite of death, stroke and systemic embolism 1 year after LAA closure (Kaplan-Meier estimated rate 9.4% for AC vs. 12.8% for APT; p log rank = 0.45). After adjustment, the difference in outcome between the groups was still similar (HR 0.94 [95%-CI 0.38-2.28; p=0.89]). Also bleeding events were not significantly different among the groups 1 year after the procedure (major bleeding 4.0% vs. 2.0%, p=0.23; moderate bleeding 4.0% vs. 4.9%, p=1.00; any bleeding 8.0% vs. 6.9%, p=0.73).

Conclusions:  Postprocedural antithrombotic treatment with AC and APT showed comparable results regarding the composite of death, stroke and systemic embolism as well as regarding bleeding complications after LAA closure. The present study confirms the results from randomized trials showing APT to be safe and effective after LAA closure.