Prevention of Recurrent Venous ThromboembolismN Engl J Med Apr 10 2003;348(15) :1425-1434PREVENT (Warfarin) Trial

Warfarin (target INR, 1.5-2.0)(n = 255)Placebo(n = 253)Endpoints (mean follow-up 2.1 years):Primary 1) recurrent venous thromboembolism and 2) composite of recurrent venous thromboembolism, major hemorrhage, or deathPREVENT TrialN Engl J Med Apr 10 2003;348(15) :1425-1434Open-label therapy for 28 days To determine if warfarin dose could be titrated to an INR of 1.5 to 2.0 without exceeding 10 mg per day To see if patients could maintain a compliance of 85%508 patients with documented idiopathic venous thromboembolism, >3 uninterrupted months of oral anticoagulation therapy with full-dose warfarinAge >30 years

PREVENT Trial: Composite EndpointPlaceboN Engl J Med Apr 10 2003;348(15) :1425-1434* Composite of recurrentthromboembolism, major bleed and deathCompositeEndpoint*HR = 0.52, p=0.01Trial discontinued early by the DSMB, due to a large, significant benefit with low-intensity warfarin therapy and the absence of any substantial evidence of any significant untoward side effectsWarfarin

PREVENT TrialN Engl J Med Apr 10 2003;348(15) :1425-1434WarfarinPlaceboRecurrent VenousThromboembolismHR = 0.36, p

PREVENT: Conclusions Among patients with idiopathic venous thromboembolism who had received full-dose anticoagulation therapy for six months, treatment with low-intensity warfarin (target INR, 1.5-2.0) was associated with a reduction in recurrent venous thromboembolism and in the composite of recurrent venous thromboembolism, major hemorrhage, or death during follow-up

No significant excess major bleeding occurred in the warfarin arm

First randomized trial to examine the use of low-intensity warfarin therapy, rather than full-dose therapy in this population