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Updated: May 5, 2026
The WATCHMAN Left Atrial Appendage Closure Device for Atrial Fibrillation
Published on: February 28, 2012
Meta-analysis: antithrombotic therapy to prevent stroke in patients who have nonvalvular atrial fibrillation
Robert G Hart1, Lesly A Pearce, Maria I Aguilar
1Department of Medicine (Neurology), University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA. hartr@uthscsa.edu
Insights
Warfarin and antiplatelet agents significantly reduce stroke risk in patients with atrial fibrillation. Warfarin offers superior efficacy compared to antiplatelet therapy, with minimal increases in bleeding risk.
Area of Science:
- Cardiology
- Neurology
- Pharmacology
Background:
- Atrial fibrillation (AF) is a significant independent risk factor for stroke.
- Stroke prevention in AF patients is a critical clinical challenge.
Purpose of the Study:
- To evaluate the efficacy and safety of antithrombotic agents for stroke prevention in patients with atrial fibrillation.
- To update a previous meta-analysis with 13 recent randomized controlled trials.
Main Methods:
- Systematic review and meta-analysis of published randomized trials.
- Included trials tested antithrombotic agents in nonvalvular atrial fibrillation patients with mean follow-up >= 3 months.
- Data extraction focused on interventions, participants, stroke, bleeding, and mortality.
Main Results:
- Twenty-nine trials (28,044 participants) were analyzed.
- Adjusted-dose warfarin reduced stroke by 64%; antiplatelet agents reduced stroke by 22%.
- Warfarin demonstrated 39% greater efficacy than antiplatelet therapy, with small absolute increases in major extracranial hemorrhage.
Conclusions:
- Adjusted-dose warfarin and antiplatelet agents are effective in reducing stroke in atrial fibrillation patients.
- Warfarin is substantially more efficacious than antiplatelet therapy for stroke prevention.
- Antithrombotic therapy provides a favorable balance of stroke reduction over bleeding risk in AF.
Background:
Atrial fibrillation is a strong independent risk factor for stroke.
Purpose:
To characterize the efficacy and safety of antithrombotic agents for stroke prevention in patients who have atrial fibrillation, adding 13 recent randomized trials to a previous meta-analysis.
Data Sources:
Randomized trials identified by using the Cochrane Stroke Group search strategy, 1966 to March 2007, unrestricted by language.
Study Selection:
All published randomized trials with a mean follow-up of 3 months or longer that tested antithrombotic agents in patients who have nonvalvular atrial fibrillation.
Data Extraction:
Two coauthors independently extracted information regarding interventions; participants; and occurrences of ischemic and hemorrhagic stroke, major extracranial bleeding, and death.
Data Synthesis:
Twenty-nine trials included 28,044 participants (mean age, 71 years; mean follow-up, 1.5 years). Compared with the control, adjusted-dose warfarin (6 trials, 2900 participants) and antiplatelet agents (8 trials, 4876 participants) reduced stroke by 64% (95% CI, 49% to 74%) and 22% (CI, 6% to 35%), respectively. Adjusted-dose warfarin was substantially more efficacious than antiplatelet therapy (relative risk reduction, 39% [CI, 22% to 52%]) (12 trials, 12 963 participants). Other randomized comparisons were inconclusive. Absolute increases in major extracranial hemorrhage were small (< or =0.3% per year) on the basis of meta-analysis.
Limitation:
Methodological features and quality varied substantially and often were incompletely reported.
Conclusions:
Adjusted-dose warfarin and antiplatelet agents reduce stroke by approximately 60% and by approximately 20%, respectively, in patients who have atrial fibrillation. Warfarin is substantially more efficacious (by approximately 40%) than antiplatelet therapy. Absolute increases in major extracranial hemorrhage associated with antithrombotic therapy in participants from the trials included in this meta-analysis were less than the absolute reductions in stroke. Judicious use of antithrombotic therapy importantly reduces stroke for most patients who have atrial fibrillation.
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