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

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