Silent thrombosis of a WATCHMAN device after Left Atrial Appendage ClosureDate from the RESET registry

Introduction Left atrial appendage (LAA) closure (LAAC) is recommended in patients (pts) with non-valvular atrial fibrillation (AF) and a contra indication (CI) to long-term oral anticoagulation (OAC).We sought to determine incidence and risk factors for WATCHMAN device (WM) thrombosis. Methods LAAC with a WM was done in 100 consecutive pts prospectively included in the monocentric RESET Registry. No thromboembolic event occurred. Transoesophageal echocardiography (TOE) was done in 57 pts at a median of 53 days (22–460) and Cardiac Computed Tomography Angiography (CCTA) in 62 at a median of 175 days (33–792). LAA thrombus against the device was detected by TOE or CCTA in 5 pts. We compared characteristics of the group with (DT) or without (N-DT) device thrombosis. Results A major bleeding was the CI for OAC in 77 pts (96%) and only 8 received anticoagulation for 45 days after LAAC. Thereafter, 58 received aspirin (73%), 20 no treatment (25%) and 2 an OAC. LAA thrombus was detected in 2 pts by TOE (51 and 98 days) and 3 by CCTA (178, 183 and 447 day) and resolved on OAC. Incidence at 1 year was 5.1% (4/78). No significant difference was observed between the 2 groups. Although DT had a tendency of higher CHA2DS2-VASc (5 ± 1.6 vs. 4.6 ± 1.4) or HAS-BLED (4.6 ± 0.5 vs. 4.4 ± 1) scores, permanent AF (60% vs. 48%), intracranial haemorrhage (80% vs. 48%), no difference in term of history of stroke/TIA (60% vs. 70%) or antiplatelet treatment (80% vs. 60%) was noted. Morphology of LAA was in all cases a non-chicken-wing (vs. 67%). Conclusion Although LAAC is limited to patients with multiple comorbidities that are reluctant to TOE, incidence of LAA thrombosis after WM implantation is high enough to strongly recommend device surveillance. Nevertheless, the optimal timing for imaging remains unclear and repetitive studies could be necessary in specific conditions. Medical history and morphologic characteristics of LAA are of limited help to identify high-risk patients.