Background:
Left atrial appendage closure (LAAC) effectively prevents stroke in atrial fibrillation (AF) patients who cannot tolerate long-term anticoagulation. However, thrombus may develop on the atrial surface of the device and potentially lead to embolisation.
Purpose:
The aim of our study was to evaluate the safety, technical efficacy and the incidence of device-related thrombus (DRT) evaluated by contrast-TEE 6 weeks and 6 months after implantation of a Watchmann Flex-occluder
Methods:
At our hospital, from April 2021 to May 2026, 108 consecutive pts with AF and underwent transcatheter LAA-closure using the Watchmann Flex-occluder. Post LAAC-antithrombotic therapy consisted of dual antiplatelet therapy in 98 pts. (93%), 20 pts., 8 pts received only SAPT, 2 NOAC only. Complete contrast-TEE-follow-up was done after 6 weeks and 6 months post procedure in 91 pts.(87%).
Results:
Out of 105 (pts, mean age of 77.20 (SD: 7.42), female 39 (36.1%); mean CHA2DS2 VASC score was 5.73 SD (1.23) and HAS BLED score was 5.03 (0.6); mean (SD). The Watchmann Flex-occluder was technically successful implanted in 105 of 108 (97,2%) pts.
Peri-interventional complications were only minor (4 pts (3,85%) had mild bleeding from the puncture site, 1 pts. makrohematuria, 1 pt Esophagus-hematoma from TEE probe. None of the pts. developed cardiac tamponade.
Postprocedural device leak >5mm was detected in 2 pts. (2,2%) after 6 months : a leak 1-3 mm was detected in 37 pts, 30pts and no leak was detected in 31 pts. (42%)
Mean shoulder was 3.55 mm (+/- 1.68) after 6 months; Mean compression was 80% (+/-9%).
TEE-follow-up: 19/91 (21%) pts experienced thrombus formation on the device after 6 weeks (13 pts) respectively 6 months (6 pts inclus. two recurrences). Two of these 19 pts. pts (10%) suffered a stroke. patient suffered a multi-locular stroke few weeks after LAAC w/o thrombus formation (1,5%).
Clinical-folllow-up: In the median follow-up period of 3.1 years 3 pts (3,3%) experienced stroke, two out of these died from the stroke;1 pt. experienced TIA. In total, 21 patients died (19,6%), 19 pts not LAAC-related. 2 pts. (10.5%) out of 19 pts. with DRT experienced stroke, 2 pts. died DRT-related death. However the group with thrombi showed with 88% (10%) vs. 80% (p 0.004) significantly reduced LAAC-compression at 6 months.
Procedural data, safety profile and leak grade by TEE did not differ significantly between groups (with/without thrombi)
Conclusion:
Transcatheter LAAC using the Watchman-Flex Device is feasible and nearly uncomplicated and a 3.3% longterm stroke rate only (CHADSVasc 5,73), but nevertheless a higher incidence of paroxysmal thrombus formation (21%) was detected despite optimal implantation of the LAA occluder.
Further optimisation of antithrombotic therapy might further lower the stroke rate after LAAC.
Keywords: left atrial appendage closure, Watchman Flex, atrial fibrillation, device-related thrombus
