Device-related thrombus post WATCHMAN implantation in the real world: lessons from a prospective multicenter registry of high-volume operators in the US

Background The FDA approved the WATCHMAN device in March 2015 with the caveat follow-up transesophageal echo (TEE) at 45 days and 1 year post implant to assess peri-device leak (PDL) and device-related thrombus formation (DRT) as an important step before interruption of anticoagulation. However, our understanding of these PDLs and DRTs relies on well designed and published clinical trials. The real-world experience regarding these issues is lacking. We sought to evaluate the DRT incidence at follow-up by TEE and CT to one year as adjudicated by a central core lab to minimize variability in reporting. Methods Patients were eligible for enrollment in this prospective registry if they were scheduled to undergo implantation with a WATCHMAN FLX or WATCHMAN FLX Pro device. Enrolled patients were implanted with a WATCHMAN device and followed per local standard of care without interference from the central core lab or study leadership. There were no pre-specified endpoints, but analyses include procedural success, procedural complications, and leak and thrombus rates as adjudicated by a central imaging core lab. Results At the time of the first follow-up, up to 90 days, 2.3% (21/916) of patients had a DRT as detected by TEE and 1.9% (13/676) of patients had a DRT as detected by CT (Figure 1). Conclusion As observed in well-controlled clinical studies, DRTs remain low post WATCHMAN implant both on TEE and CT. This experience expands our understanding of visualization of DRT beyond TEE to incorporate the modern practice of using CT for follow-up in patients post WATCHMAN implant.