Abstract 14778: Watchman Associated With Lower Risk of Stroke and Mortality in Patients With Atrial Fibrillation and Difficulties Taking Anticoagulation

Abstract

Introduction: Watchman has been increasingly used in AF patients who have difficulties taking anticoagulation, but the RCTs only compared Watchman to warfarin. There was also a signal of increased ischemic stroke with Watchman in comparison to warfarin in RCTs, which made some clinicians question the fundamental premise that Watchman can reduce stroke. We aimed to compare Watchman to no anticoagulation in a large national cohort of patients in the US. Methods: We identified AF patients treated with Watchman (N=7,309) or no anticoagulation (N=1,234,543) between 2015-2017 from the OptumLabs Data Warehouse, which is the first to link private insurance, Medicare Advantage, and Medicare Fee-for-Service records at patient level longitudinally. One-to-one propensity score matching was used to balance patients on demographics and medical history. The primary outcomes were ischemic stroke or systemic embolism (hereafter referred to as stroke) and major bleeding. Secondary outcomes included all-cause mortality and intracranial bleeding. Results: In the unmatched cohort, the mean age was 76.6±6.4 yr in the Watchman group and 76.6 ±8.5 yr in the no anticoagulation group, but Watchman patients were more likely to have a history of bleeding (44.9% vs 13.7%) and intracranial bleeding (9.5% vs 2.6%). After matching, the two groups were similar on 18 baseline characteristics. Watchman was associated with a lower risk of stroke and mortality, but a higher risk of major bleeding and a similar risk of intracranial bleeding. The associations were largely consistent across subgroups, including those with relative contraindications to anticoagulation (Figure). Conclusions: In AF patients who had difficulties taking anticoagulation, Watchman offers an alternative approach to reduce stroke and mortality. The results provide important evidence to inform clinical decision making in the absence of RCTs, since 40% of AF patients in routine practice are not on anticoagulation.