Boston Scientific initiates trial comparing left atrial appendage closure to direct oral anticoagulants for stroke risk reduction post-AFib ablation

Watchman FLX device (Boston Scientific)

According to a press release, Boston Scientific has initiated the OPTION trial to compare safety and effectiveness of the next-generation Watchman FLX left atrial appendage closure platform to first-line oral anticoagulants (OAC)—including direct oral anticoagulants (DOAC) and warfarin—for stroke risk reduction in patients with non-valvular atrial fibrillation (AF) who undergo a cardiac ablation procedure.

Approximately 33 million patients worldwide have AF, a common heart rhythm disorder.1 In recent years, the number of US patients who have undergone an in-hospital cardiac ablation procedure to prevent abnormal electrical signals from moving through the heart has grown tenfold.2 More than 50% of those patients become asymptomatic, making them less likely to adhere to current guidelines recommending the continuation of OAC post-procedure to reduce the risk of stroke.3,4 Stroke is five times more likely to occur in patients with AF than in someone with a normal heart rhythm.5

“Cardiac ablation is an effective way to treat an abnormal heart rhythm for many patients, though symptomatic relief can lead these patients to stop taking their blood thinners and unknowingly put themselves at an elevated risk for a stroke,” said Oussama Wazni, co-director of the Ventricular Arrhythmia Center, Center for Atrial Fibrillation and the Atrial Fibrillation Stroke Prevention Center at Cleveland Clinic (Cleveland, USA) and the principal investigator for the OPTION trial. “This first-of-its-kind trial will explore whether the one-time Watchman FLX device could replace commonly used anticoagulants for long-term stroke risk reduction in this growing patient population.”

The randomised, controlled OPTION trial will enrol 1,600 patients with non-valvular AF who are suitable for OAC therapy and have recently had or will have an ablation. Patients at as many as 130 global sites will be randomised to receive the newest-generation Watchman FLX device or an OAC, inclusive of commonly prescribed DOACs or warfarin. The primary effectiveness endpoint is all cause death, stroke and systemic embolism through 36 months, and the primary safety endpoint is non-procedural bleeding through 36 months.

“Beyond advancing the robust clinical literature supporting the Watchman therapy, findings from the OPTION trial have the potential to expand the number of patients with atrial fibrillation who can receive an alternative to life-long anticoagulants and thus avoid their potential side effects,” said Ian Meredith, executive vice president and global chief medical officer, Boston Scientific. “The unique study design encompasses patients who will receive a Watchman FLX device either after or concurrent to an ablation procedure.”

The Watchman device has been implanted in more than 80,000 patients worldwide and the latest-generation Watchman FLX device received CE Mark in March 2019. In the USA, the Watchman FLX device is an investigational device and not available for sale.


1. Chugh SS, et al. Worldwide epidemiology of atrial fibrillation: a global burden of disease 2010 study. Circulation 2014;129:837–847. doi:

2. Hosseini S, et al. Catheter ablation for cardiac arrhythmias: utilization and in-hospital complications 2000-2013. JACC: Clinical Electrophysiology. 2017. doi:

3. Arbelo E, et al. Contemporary management of patients undergoing atrial fibrillation ablation: in-hospital and 1-year follow-up findings from the ESC-EHRA atrial fibrillation ablation long-term registry. European Heart Journal. 2017. doi:

4. Calkins H, et al. 2017 HRS/EHRA/ECAS/APHRS/SOLAECE expert consensus statement on catheter and surgical ablation of atrial Fibrillation. Heart Rhythm Journal. 2017. doi:

5. Atrial Fibrillation Fact Sheet.” Centers for Disease Control and Prevention.


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