Risk of device-related thrombosis following short-term oral anticoagulation with low-dose dabigatran versus warfarin after Watchman left atrial appendage occlusion

Background: Percutaneous left atrial appendage occlusion (LAAO) provides an alternative for poor candidates for long-term oral anticoagulation (OAC). To prevent device-related thrombosis (DRT), OAC should be continued for the first 45 days to allow complete endothelialization post-LAAO implantation. Whereas, evidence is limited on the feasibility and safety of direct oral anticoagulants (DOACs) used after LAAO. Methods: This was a retrospective observational single-center study of AF patients undergoing LAAO with a Watchman device and receiving either low-dose dabigatran (110mg twice daily) or warfarin in the peri- and post-procedural period for 45 days. Transesophageal echocardiography was scheduled to perform at 6 weeks, 6 months, and 12 months after the procedure to assess the stability of the device and to detect DRT. Incidence of thromboembolic and bleeding events were also evaluated during the follow-up period. Results: There were a total of 84 patients who successfully underwent Watchman implantation, with 38 patients (45.2%) receiving low-dose dabigatran and 46 patients (54.8%) using warfarin post-LAAO. Peri-procedural complications occurred in 10 patients, with 3 patients in the dabigatran group and 7 patients in the warfarin group (7.9% vs. 15.2%, p = 0.30). During the 12-month follow-up, 1 patient experienced major bleeding and 16 patients suffered minor bleeding in the warfarin group, while 5 patients treated with dabigatran had minor bleeding (34.8% vs. 13.2%, p = 0.02). Besides, 6 DRT (15.8%) were detected in dabigatran groups, and the incidence was higher than in the warfarin group (15.8% vs. 2.2%, p = 0.03). No DRT-related ischemic events were found. Conclusions: This study suggested that short-term low-dose dabigatran (110 mg twice daily) could significantly decrease the risk of bleeding compared with warfarin at the expense of increased risk of DRT post-LAAO. Therefore, low-dose dabigatran should be used with caution for post-implant anticoagulation of LAAO. Further studies are urgently needed on the feasibility and safety of DOACs post-LAAO.