"Aspirin for the Secondary Prevention of Venous Thromboembolism". The New England Journal of Medicine. 2012. 366:1959-1967. PubMed•Full
Links to original sources: Wiki Journal Post Full Journal Article
Contents 1 Clinical Question 2 Bottom Line 3 Major Points 4 Guidelines 5 Design 6 Population 6.1 Inclusion Criteria 6.2 Exclusion Criteria 6.3 Baseline Characteristics 7 Interventions 8 Outcomes 8.1 Primary Outcome 8.2 Secondary Outcomes 9 Funding 10 Further Reading
In patients with unprovoked venous thromboembolism who have completed 6 to 18 months of oral anticoagulant treatment, does aspirin reduce the risk of recurrence without increasing the risk of major bleeding compared with placebo?
Aspirin reduces the risk of recurrent venous thromboembolism by about 40% after discontinuation of anticoagulant treatment, without a significant increase in major bleeding events.
Approximately 20% of patients with unprovoked venous thromboembolism experience a recurrence within two years of stopping oral anticoagulant therapy. The WARFASA trial found that 100mg of aspirin daily, initiated after 6 to 18 months of anticoagulant therapy, reduces the recurrence rate of venous thromboembolism, providing an alternative to indefinite anticoagulation in selected patients.
Current guidelines may not yet reflect the findings of this trial.
- Multicenter, investigator-initiated, double-blind, randomized, placebo-controlled trial - N=402 patients with unprovoked venous thromboembolism - Aspirin 100 mg daily (n=205) or placebo (n=197) - Median follow-up: 24.6 months - Analysis: Modified intention-to-treat - Primary efficacy outcome: Recurrence of venous thromboembolism - Primary safety outcome: Major bleeding
Inclusion Criteria - Age over 18 years - Completed 6 to 18 months of vitamin K antagonist treatment for first-ever, unprovoked proximal deep-vein thrombosis or pulmonary embolism
Exclusion Criteria - Venous thromboembolism provoked by a known risk factor - Patients with significant bleeding during initial anticoagulant treatment or with other conditions contraindicating aspirin use (see Supplementary Appendix for detailed criteria)
Baseline Characteristics - Demographics, clinical characteristics, and comorbidities balanced between the two groups
- Aspirin, 100 mg once daily, or placebo for 2 years, with the option to extend treatment
Primary Outcome - Recurrent venous thromboembolism occurred in 28 of the 205 patients in the aspirin group and in 43 of the 197 patients in the placebo group (6.6% vs. 11.2% per year; hazard ratio, 0.58; 95% CI, 0.36 to 0.93; P=0.02)
- Two major bleeding events, one in each treatment group - Additional secondary efficacy outcomes included nonfatal myocardial infarction, unstable angina, stroke, transient ischemic attack, acute ischemia of the lower limbs, and death from any cause
- University of Perugia, grant-in-aid from Bayer HealthCare, and an Aventis Fellowship for Clinical Research from the International Society of Thrombosis and Haemostasis.
- Original article in The New England Journal of Medicine - Supplementary Appendix available at NEJM.org