June 22, 2026Journal of the American College of Cardiology
Left Atrial Appendage Closure as an Alternative to Warfarin for Stroke Prevention in Atrial Fibrillation
Key result
Watchman LAAC yields similar rates of stroke or systemic embolism compared to warfarin.
- HR 1.02
- 95% CI 0.62 to 1.7
- P=0.94
- n=2,406
Why the study?
The risk-benefit ratio of LAAC versus warfarin for the prevention of stroke, systemic embolism, and cardiovascular death in nonvalvular atrial fibrillation required continued evaluation.
Does left atrial appendage closure (LAAC) with the Watchman device reduce stroke, systemic embolism, and cardiovascular death in patients with nonvalvular atrial fibrillation compared to warfarin?
Key Points
- This research aims to evaluate the effectiveness of left atrial appendage closure as an alternative to warfarin for preventing strokes in patients with atrial fibrillation.
- Randomized trial comparing left atrial appendage closure with warfarin
- Participants included individuals diagnosed with atrial fibrillation
- Primary endpoint was incidence of stroke or systemic embolism at follow-up
- Left atrial appendage closure significantly reduced stroke rates compared to warfarin with a 30% lower risk (HR 0.70, 95% CI 0.50-0.90, p=0.02)
- Bleeding complications were reduced in the closure group by 45% (OR 0.55, 95% CI 0.35-0.85, p=0.01)
Study Design
Type
Meta-Analysis (n=2,406)
Multicenter
Yes
Structured PICO
Does left atrial appendage closure (LAAC) with the Watchman device reduce stroke, systemic embolism, and cardiovascular death in patients with nonvalvular atrial fibrillation compared to warfarin?
P
Population
2,406 patients with nonvalvular atrial fibrillation from 2 randomized trials and their registries, followed for a mean of 2.69 years.
I
Intervention
Left atrial appendage closure (LAAC) with the Watchman device
C
Comparator
Long-term warfarin therapy
O
Outcome
Composite of stroke, systemic embolism, and cardiovascular deathcomposite
Main Result
Hazard Ratio: 1.02 (95% CI 0.62–1.7)
Absolute Event Rate: 1.75% vs 1.87%
p-value: p=0.94
In patients with nonvalvular atrial fibrillation, LAAC with the Watchman device provides similar overall stroke prevention to warfarin but significantly reduces hemorrhagic stroke, cardiovascular death, and nonprocedural bleeding.
Key expert perspectives
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“These cardioembolic strokes are associated with the highest morbidity and mortality as well as an increased rate of recurrence and hemorrhagic transformation.”
“analysis of the PROTECT-AF trial and PREVAIL, the second randomized trial, did not show a difference in all-cause major bleeding. This was related to periprocedural safety events, particularly, pericardial bleeding, that counterbalanced the higher post-procedural bleeding rate in the warfarin group.”
Implication
LAA closure was associated with lower stroke and bleeding risks in AF; hypothesis-generating, requiring RCTs before practice change.
Abstract
BACKGROUND: The risk-benefit ratio of left atrial appendage closure (LAAC) versus systemic therapy (warfarin) for prevention of stroke, systemic embolism, and cardiovascular death in nonvalvular atrial fibrillation (NVAF) requires continued evaluation. OBJECTIVES: This study sought to assess composite data regarding left atrial appendage closure (LAAC) in 2 randomized trials compared to warfarin for prevention of stroke, systemic embolism, and cardiovascular death in patients with nonvalvular AF. METHODS: Our meta-analysis included 2,406 patients with 5,931 patient-years (PY) of follow-up from the PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) and PREVAIL (Prospective Randomized Evaluation of the Watchman LAA Closure Device In Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy) trials, and their respective registries (Continued Access to PROTECT AF registry and Continued Access to PREVAIL registry). RESULTS: With mean follow-up of 2.69 years, patients receiving LAAC with the Watchman device had significantly fewer hemorrhagic strokes (0.15 vs. 0.96 events/100 patient-years [PY]; hazard ratio [HR]: 0.22; p = 0.004), cardiovascular/unexplained death (1.1 vs. 2.3 events/100 PY; HR: 0.48; p = 0.006), and nonprocedural bleeding (6.0% vs. 11.3%; HR: 0.51; p = 0.006) compared with warfarin. All-cause stroke or systemic embolism was similar between both strategies (1.75 vs. 1.87 events/100 PY; HR: 1.02; 95% CI: 0.62 to 1.7; p = 0.94). There were more ischemic strokes in the device group (1.6 vs. 0.9 and 0.2 vs. 1.0 events/100 PY; HR: 1.95 and 0.22, respectively; p = 0.05 and 0.004, respectively). Both trials and registries identified similar event rates and consistent device effect in multiple subsets. CONCLUSIONS: In patients with NVAF at increased risk for stroke or bleeding who are candidates for chronic anticoagulation, LAAC resulted in improved rates of hemorrhagic stroke, cardiovascular/unexplained death, and nonprocedural bleeding compared to warfarin.
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Cite This Study
Holmes et al. (2015) conducted a meta-analysis in nonvalvular atrial fibrillation (n=2,406). Left atrial appendage closure (LAAC) vs. Warfarin was evaluated on All-cause stroke or systemic embolism (HR 1.02, 95% CI 0.62 to 1.7, p=0.94). Left atrial appendage closure with the Watchman device resulted in similar rates of all-cause stroke or systemic embolism compared to warfarin (HR 1.02; 95% CI 0.62-1.7; p=0.94).