"Efficacy and safety outcomes of oral anticoagulants and antiplatelet drugs in the secondary prevention of venous thromboembolism: systematic review and network meta-analysis"
BMJ Aug 30
http://www.bmj.com/content/347/bmj.f5133
"Conclusions All oral anticoagulants and antiplatelet agents investigated in this analysis were associated with a reduced recurrence of venous thromboembolism compared with placebo or observation, although acetylsalicylic acid was associated with the lowest risk reduction. Vitamin K antagonists given at a standard adjusted dose was associated with the greatest risk reduction in recurrent venous thromboembolism, but also the greatest risk of major bleeding."