Evaluating the New Watchman FLX Pro 40 mm Device: A Case Study Series.

Background: Left atrial appendage closure (LAAC) is a well-established alternative for stroke prevention in patients with atrial fibrillation (AF) who are not suitable for long-term anticoagulation. The WATCHMAN FLX Pro 40 mm device is a novel advancement featuring a fluoropolymer coating to enhance thromboresistance and a size expansion to accommodate larger left atrial appendages (LAA). However, clinical data on this new device remains limited.

Objective: This study presents the first case series evaluating the procedural success, safety, and early outcomes of the 40 mm WATCHMAN FLX Pro device.

Methods: A total of nine patients underwent LAAC with the 40 mm WATCHMAN FLX Pro between July and November 2024. Pre-procedural imaging, intraoperative guidance, procedural outcomes, and follow-up imaging were analyzed. Procedural success was defined by the successful deployment of the device meeting "PASS" criteria, with no major complications.

Results: The study demonstrated a 100% procedural success rate, with all patients undergoing same-day discharge. No procedural or periprocedural complications were observed. Follow-up imaging at 4 months (available for 88.9% of patients) revealed no high-grade device-related thrombus (DRT), though some cases exhibited peridevice leaks, predominantly minor subfabric leaks.

Conclusion: The 40 mm WATCHMAN FLX Pro expands LAAC treatment options for patients with larger LAA anatomy, demonstrating a favorable safety and efficacy profile in this early experience. Larger studies with long-term follow-up are needed to validate these findings.