Incidence and predictors of device-related thrombus after left atrial appendage closure with Watchman device.

Introduction: Left atrial appendage closure (LAAC) with Watchman device prevents thromboembolism in patients with atrial fibrillation (AF). However, thrombus may develop on the atrial surface of the device.

Aim: To investigate the incidence and predictors of device-related thrombus (DRT) in patients with AF who were treated with LAAC.

Material and methods: Ninety-one consecutive patients with AF underwent LAAC procedure using first-generation Watchman 2.5 device followed by antiplatelet therapy. In our analysis we have included all patients (n = 78) who had clinical follow-up visits with transesophageal echocardiography (TEE) after the procedure.

Results: The median (IQR) CHA₂DS₂-VASc score was 4 (4.0-6.0) and HAS-BLED score was 3 (3.0-4.0). DRTs were observed in 5 (6.4%) patients. When compared with patients without DRT, those with DRT presented more often with lower median ejection fraction (40% (23.5-45.5) versus 55% (48.0-60.0); p = 0.005), lower emptying velocity of LAA (25 cm/s (17.5-27.0) versus 53 cm/s (26.5-78.0); p = 0.009), and with greater depth of implantation (18 mm (14.0-20.5) versus 8 mm (5.0-11.0); p < 0.001). Furthermore, patients with DRT had greater depth of LAA (35 mm (29.5-41.0) versus 29 mm (25.5-31.0); p = 0.003), greater mean (SD) dimension in 90⁰ (22.4 mm (3.2) versus 19 mm (2.7); p = 0.02). Patients with DRT were also younger than those without DRT (67.4 years (7) versus 75 years (8.3), p = 0.045).

Conclusions: The DRT after Watchman device implantation remains a rare complication. Its formation was related to several patient and procedural characteristics, which need to be confirmed in larger studies.