Journal of Thrombosis and Thrombolysis

, Volume 21, Issue 1, pp 51–52

Low Intensity Warfarin Anticoagulation is Safe and Effective as a Long-Term Venous Thromboembolism Prevention Strategy



Longitudinal studies indicate a high rate of recurrence of venous thromboembolism after an episode of deep venous thrombosis or pulmonary embolism. Extended anticoagulant therapy will decrease the recurrence rate, but there is controversy as to the optimal intensity of therapy that will be effective, yet safe. The PREVENT trial addresses the question of whether long-term low intensity therapy (INR 1.5–2.0) will effectively prevent recurrence compared to placebo treatment, yet be safe without a significant increase in major bleeding. The results of this trial show a significant reduction in recurrent venous thromboembolism with a major bleeding rate that is no different than the placebo arm of the study (0.9 vs 0.4 per 100 patient years; p = 0.25). Although the ELATE trial showed greater effectiveness with no increase in bleeding in the standard intensity arm vs the low intensity arm, the question remains whether such safety can be obtained in the real world management of oral anticoagulation.

Key Words

warfarin venous thromboembolism INR treatment 


  1. 1.
    Schulman S, Rhedin AS, Lindmarker P, et al. A comparison of six weeks with six months of oral anticoagulant therapy after a first episode of venous thromboembolism. Duration of Anticoagulation Trial Study Group. N Engl J Med 1995;332(25):1661–1665.CrossRefPubMedGoogle Scholar
  2. 2.
    Prandoni P, Lensing AW, Cogo A, et al. The long-term clinical course of acute deep venous thrombosis. Ann Intern Med 1996;125(1):1–7.PubMedGoogle Scholar
  3. 3.
    Heit JA, Mohr DN, Silverstein MD, Petterson TM, O'Fallon WM, Melton LJ, 3rd. Predictors of recurrence after deep vein thrombosis and pulmonary embolism: a population-based cohort study. Arch Intern Med 2000;160(6):761–768.PubMedGoogle Scholar
  4. 4.
    Kearon C, Gent M, Hirsh J, et al. A comparison of three months of anticoagulation with extended anticoagulation for a first episode of idiopathic venous thromboembolism. N Engl J Med 1999;340(12):901–907.CrossRefPubMedGoogle Scholar
  5. 5.
    Ridker PM, Goldhaber SZ, Danielson E, et al. Long-term, low-intensity warfarin therapy for the prevention of recurrent venous thromboembolism. N Engl J Med 2003;348(15):1425–1434.CrossRefPubMedGoogle Scholar
  6. 6.
    Schulman S, Granqvist S, Holmstrom M, et al. The duration of oral anticoagulant therapy after a second episode of venous thromboembolism. The Duration of Anticoagulation Trial Study Group. N Engl J Med 1997;336(6):393–398.CrossRefPubMedGoogle Scholar
  7. 7.
    Kearon C, Ginsberg JS, Kovacs MJ, et al. Comparison of low-intensity warfarin therapy with conventional-intensity warfarin therapy for long-term prevention of recurrent venous thromboembolism. N Engl J Med 2003;349(7):631–639.CrossRefPubMedGoogle Scholar

Copyright information

© Springer Science + Business Media, Inc. 2006

Authors and Affiliations

  1. 1.Cardiovascular Division, Department of MedicineBrigham and Women's Hospital, Harvard Medical SchoolBoston

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