Follow-Up Imaging after Left Atrial Appendage Closure

Abstract Background Because device-related thrombus (DRT) portends a poor prognosis after left atrial appendage closure with the Watchman device, surveillance transesophageal echocardiograms (TEEs) are recommended at 45 days and 1 year. However, oral anticoagulants are just stopped at 45 days, rendering this early TEE unlikely to detect DRT. Indeed, DRT is most likely to occur after instituting aspirin monotherapy. Objective To evaluate the alternative strategy of first TEE imaging (or computed tomography; CT) at 4 months post-Watchman implantation. Methods After FDA approval, consecutive patients undergoing Watchman implantation at 2 centers received TEEs or CTs at 4 months and 1 year, along with a truncated drug regimen: 6 weeks of an oral anticoagulant (or clopidogrel in a subset) plus aspirin, then 6 weeks dual antiplatelet therapy, then aspirin monotherapy. Results Of the 530-patient cohort (age 78.7±7.9; 65.5% male; CHA2DS2-VASc 4.5±1.4), 465 (87.7%) received 4-month imaging: 83.0% (440/530) TEE, and 4.7% (25/530) CT. Over median 12 months follow-up, 16 ischemic strokes (IS), 8 transient ischemic attacks (TIA), and 1 systemic embolization (SE) occurred. Importantly, no IS occurred between 45 days and 4 months; the sole TIA in this period (at ∼2 months) occurred 1 week after transcatheter aortic valve replacement. DRT was detected in 2.4% (11/465) at 4 months and 0.9% (2/214) at 1 year. No IS, but one leg embolization, was observed after DRT detection. Conclusion Delaying first post-Watchman imaging to 4 months was associated with no ischemic strokes between 45 days and 4 months – the "vulnerable" period of this follow-up strategy.