AimsThe left atrial appendage closure (LAAC) by Watchman device is possible in atrial fibrillation patients unsuitable for anticoagulation treatment. However, post procedural treatment is still in debate. The aim of this study is to compare the efficacy and safety of light post-operative antithrombotic strategies.MethodsAn observational and multicentric study included all consecutive patients implanted with a Watchman device between January 2013 and December 2018. All patients presented definitive contraindication to anticoagulant therapy. The primary efficacy endpoint was the occurrence of thromboembolic event, major bleeding or death within a year following implantation. Safety endpoint was a composite criterion of procedural complications or major bleeding during follow up. The groups of treatment compared no treatment, single or dual antiplatelet therapy after the initial phase (early 46 days) post LAAC.Results295 patients were included, mean age was 77 years and mean scores CHAD2S2VASc and HAS BLED were respectively 4,92 ±1,26 and 3,65 ±0,85. The mean follow-up was 23.5 months (±16). There was no statistical difference in the occurrence of the primary criterion between the three groups (p= 0,83) [Fig 1]. No additional risk depending on treatment was found. There was a risk reduction of 54% in thromboembolic events and 72% in major bleeding in comparison to the expected rate estimated by the scores [Fig 2].ConclusionThere was no difference of embolic events, major bleeding or death depending on the chosen treatment. No specific profile was found to help choosing medication. It seems possible to simplify the post procedural treatment for fragile patients.