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Updated: Sep 24, 2025
The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Patient-Level Analysis of Watchman Left Atrial Appendage Occlusion in Practice Versus Clinical Trials
Daniel J Friedman1, Chengan Du2, Yongfei Wang3
1Section of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, USA; Division of Cardiology, Duke University School of Medicine, Durham, North Carolina, USA.
Insights
Patients undergoing left atrial appendage occlusion (LAAO) in clinical practice have more comorbidities. Trial patients had higher risks of stroke and device issues, but lower mortality than registry patients.
Area of Science:
- Cardiology
- Medical Devices
- Clinical Trials
Background:
- Patients undergoing LAAO in clinical practice typically present with a higher burden of comorbidities compared to participants in clinical trials.
- This disparity necessitates a comparison of outcomes between real-world LAAO patients and those from pivotal trials.
Purpose of the Study:
- To compare outcomes between patients who underwent LAAO in the PROTECT-AF and PREVAIL trials and matched patients from the National Cardiovascular Data Registry (NCDR) LAAO Registry.
- To evaluate the safety and efficacy of LAAO in a real-world population versus a controlled trial setting.
Main Methods:
- Utilized patient-level data from the PROTECT-AF and PREVAIL LAAO trials and the NCDR LAAO Registry.
- Employed propensity-matched analyses, matching up to three registry patients to each trial patient.
- Applied Cox proportional hazards and Fine-Gray models to analyze outcomes.
Main Results:
- A total of 1,904 registry patients were matched to 667 trial LAAO patients, and 1,010 registry patients to 348 warfarin patients.
- Trial LAAO patients had higher rates of pericardial effusion requiring intervention (3.8% vs 0.6%), periprocedural ischemic stroke (0.9% vs 0.2%), and failed device implantation (7.5% vs 3.6%) compared to registry patients.
- The 425-day risk of ischemic stroke was higher in trial LAAO patients (2.70% vs 1.21%), while warfarin patients had comparable rates to registry patients. Mortality was lower in trial LAAO patients (2.92% vs 6.23%).
Conclusions:
- Patients undergoing LAAO in clinical practice, despite having more comorbidities, experienced a lower risk of ischemic stroke and similar hemorrhagic stroke risk compared to trial patients.
- Trial LAAO patients demonstrated a higher risk of death post-implant compared to registry patients, primarily due to noncardiovascular causes.
- The findings suggest differences in patient populations and outcomes between LAAO clinical trials and real-world practice.
Objectives:
The aim of this study was to compare outcomes among patients from the PROTECT-AF (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation) and PREVAIL (Evaluation of the WATCHMAN Left Atrial Appendage [LAA] Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy) left atrial appendage occlusion (LAAO) trials with matched patients from the National Cardiovascular Data Registry LAAO Registry using patient-level data.
Background:
Patients undergoing LAAO in clinical practice generally have more comorbidities than trial participants.
Methods:
Propensity-matched analyses, with up to 3 registry patients matched to each trial patient, were performed using Cox proportional hazards and Fine-Gray models.
Results:
A total of 1,904 registry patients were matched to 667 trial LAAO patients; 1,010 registry patients were matched to 348 warfarin patients. Compared with registry patients, trial LAAO patients experienced more pericardial effusion requiring intervention (3.8% vs 0.6%, P < 0.001), periprocedural ischemic stroke (0.9% vs 0.2%, P = 0.005), and failed device implantation (7.5% vs 3.6%, P < 0.001). The 425-day risk of ischemic stroke in trial LAAO patients was higher than in registry patients (2.70% vs 1.21%; HR: 1.951; P = 0.03); warfarin patients had comparable rates of ischemic stroke compared with registry patients (1.15% vs 1.29%; HR: 0.728; P = 0.57). Hemorrhagic stroke risk was similar among trial LAAO and registry patients (P = 0.88). Hemorrhagic stroke risk was greater among warfarin patients versus registry patients (1.44% vs 0.20%; HR: 5.871, P = 0.03). Mortality was lower in trial LAAO patients than in registry patients (2.92% vs 6.23%; HR: 0.477; P = 0.004), a difference attributable to noncardiovascular deaths. Mortality was similar (P = 0.44) among trial warfarin (4.48%) and registry (5.86%) patients.
Conclusion:
In clinical practice, patients who meet trial criteria and undergo LAAO experience a lower risk of ischemic stroke, a similar risk of hemorrhagic stroke, and a higher risk of death after implant versus LAAO trial patients. (WATCHMAN Left Atrial Appendage System for Embolic PROTECTion in Patients With Atrial Fibrillation [PROTECT-AF], NCT00129545; Evaluation of the WATCHMAN Left Atrial Appendage [LAA] Closure Device in Patients With Atrial Fibrillation Versus Long Term Warfarin Therapy [PREVAIL], NCT01182441).
