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Previous Volume 357:1105-1112 September 13, 2007 Number 11 Next

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ABSTRACT

Background The extended use of vitamin K antagonists for prophylaxis against venous thromboembolism is often constrained by risk–benefit limitations and inconvenience. We evaluated the efficacy and safety of a 6-month extension of prophylaxis against recurrent venous thromboembolism with idraparinux in patients who had initially received 6 months of prophylaxis with an anticoagulant.

Methods We randomly assigned patients who had completed 6 months of prophylaxis with idraparinux or a vitamin K antagonist and in whom extended anticoagulation was warranted to receive once-weekly injections of 2.5 mg of idraparinux or placebo for 6 months without monitoring. The primary efficacy and safety outcomes were recurrent venous thromboembolism and major bleeding.

Results Of 1215 patients, 6 of 594 (1.0%) in the idraparinux group and 23 of 621 (3.7%) in the placebo group had recurrent venous thromboembolism (P=0.002). Major bleeding occurred in 11 patients (1.9%) in the idraparinux group and in none in the placebo group (P<0.001). Of these 11 episodes, 3 were fatal intracranial hemorrhages. As compared with patients whose initial treatment was a vitamin K antagonist, patients whose initial treatment was idraparinux who were assigned to 6 months in the placebo group had a lower incidence of recurrent thromboembolism (0.7% vs. 5.9%); patients who received 6 additional months of idraparinux therapy had a higher incidence of major bleeding (3.1% vs. 0.9%).

Conclusions During a 6-month extension of thromboprophylaxis, idraparinux was effective in preventing recurrent thromboembolism but was associated with an increased risk of a major hemorrhage. (ClinicalTrials.gov number, NCT00071279 [ClinicalTrials.gov] .)

Source Information

The members of the writing committee (Harry R. Buller, M.D., Ander T. Cohen, M.D., Bruce Davidson, M.D., Hervé Decousus, M.D., Alex S. Gallus, M.D., Michael Gent, M.Sc., Gerard Pillion, M.D., Franco Piovella, M.D., Martin H. Prins, M.D., and Gary E. Raskob, Ph.D.) assume responsibility for the overall content and integrity of the article.

Address reprint requests to Dr. Buller at the Academic Medical Center, Department of Vascular Medicine, F4-211, Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands, or at h.r.buller{at}amc.uva.nl.

Full Text of this Article

This article has been cited by other articles:

• Gross, P. L., Weitz, J. I. (2008). New Anticoagulants for Treatment of Venous Thromboembolism. Arterioscler. Thromb. Vasc. Bio. 28: 380-386 [Abstract] [Full Text]  
• (2007). Idraparinux for Venous Thromboembolic Disorders?. Journal Watch Cardiology 2007: 5-5 [Full Text]