Why is this study important?   

• In real-world clinical practice including data from the NCDR LAAO registry, the rate of complications related to the WATCHMAN FLX implantation procedure, from the time of implantation through 45 days remains low.  Specifically, ischemic stroke occurred in only 0.28% of patients at 45 days. 
• The rate of successful LAA closure at 45 days was high (95% of patients with leak <3 mm). 

What question was this study supposed to answer?  

The safety and efficacy of WATCHMAN FLX was demonstrated in the PINNACLE FLX trial leading to FDA approval of this second generation of the Boston Scientific WATCHMAN device.  But data including a larger number of implanting physicians caring for patients in real-world clinical practice has been anticipated. 

What did the study show? 

The SURPASS analysis was designed to evaluate real-world outcomes in patients undergoing WATCHMAN FLX implantation. 16,446 patients from the NCDR Left Atrial Appendage Occlusion (LAAO) registry were included. Device implantation was successful in 97.6% of the patients. Among the 16,048 patients in whom LAAO was successful, the key safety endpoint of all-cause death, ischemic stroke, systemic embolism, device or procedure related events requiring cardiac surgery or major endovascular intervention was assessed at post-device day 7 (or at the time of hospital discharge if discharge occurred after 7 days).  0.37% of patients experienced a key safety endpoint. However, this endpoint did not include major bleeding, which was the most common complication occurring prior to hospital discharge, affecting 0.98% of patients. Interestingly, only 49.1% of patients were discharged on the regimen used in the PINNACLE FLX trial (DOAC plus aspirin), although 82.1% of patients were discharged on either warfarin or a DOAC, with or without antiplatelet therapy. At 45 day follow-up, the occurrence of adverse events was low and comparable with the PINNACLE FLX trial outcomes.  0.51% of patients had a pericardial effusion, 0.28% had ischemic stroke, which was similar to the rate of device-related thrombosis (0.23%) and 0.10% experienced a hemorrhagic stroke.  Major bleeding by 45 days occurred in 3.55% and 95% of patients had a peri-device leak <3 mm.  The SURPASS study is ongoing and patients will continue to be followed for at least 2 years post-implantation.  As longer-term data is collected, the significance of peri-device leaks of any size will, hopefully, be elucidated. 

All authors: Allison G. Dupont, MD, FSCAI