Sergio Siragusa, MD
In patients with cancer receiving chemotherapy through central venous catheters (CVCs), is catheter-related thrombosis reduced by warfarin compared with no warfarin, or by dose-adjusted warfarin compared with fixed-dose warfarin?
Randomized controlled trial (WARP). Current Controlled Trials ISRCTN50312145.
Unclear allocation concealment.*
Until thrombosis or removal of catheter.
68 centers in the UK.
1590 patients ≥ 16 years of age (median age across groups 59 to 61 y, 58% men) with histologically confirmed cancer needing a CVC for chemotherapy administration. Exclusion criteria were inadequate hepatic, renal, and hematologic function; contraindication to warfarin; current receipt of warfarin; pregnancy; and lactation.
For warfarin evaluation: warfarin (n = 408) (fixed-dose 1 mg/d [n = 324] or dose-adjusted to maintain an international normalized ratio [INR] between 1.5 and 2.0 [n = 84]) or no warfarin (n = 404). For dose evaluation: dose-adjusted warfarin (n = 473), or fixed-dose warfarin 1 mg/d (n = 471).
Radiologically confirmed, symptomatic, catheter-related thrombotic events. Secondary outcomes included non–catheter-related thrombotic events and major bleeding.
97.6% (100% in intention-to-treat analysis).
The Table shows the results.
In patients with cancer receiving chemotherapy through central venous catheters, warfarin did not affect risk for catheter-related thrombosis, all thrombotic events, or major bleeding, compared with no warfarin.
Warfarin vs no warfarin and dose-adjusted vs fixed-dose warfarin in cancer patients with central venous catheters†
†Abbreviations defined in Glossary. RRR, RRI, NNT, NNH, and CI calculated from data in article. 10% of patients contributed to both comparisons (warfarin vs no warfarin and adjusted dose vs fixed dose).
Siragusa S. Warfarin thromboprophylaxis in cancer did not reduce risk for catheter-related thrombosis. Ann Intern Med. 2009;151:JC1–5. doi: 10.7326/0003-4819-151-2-200907210-02005
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Published: Ann Intern Med. 2009;151(2):JC1-5.
Hematology/Oncology, Venous Thromboembolism.
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