This study examines whether low intensity, dose adjusted warfarin prolongs the time to mechanical failure of hemodialysis catheters without resulting in an unacceptable rate of bleeding.

Patients with end-stage renal disease receiving or about to initiate hemodialysis are randomized to receive either adjusted dose warfarin to achieve an INR of 1.5-1.9 or adjusted dose placebo within 72 hours of hemodialysis catheter placement. The primary outcome is mechanical failure of the catheter, as outlined below.

Inclusion Criteria:

• Newly placed double-lumen hemodialysis catheter

Exclusion Criteria:

• Major bleed within last 3 months
• Platelet count less than 50 x 10 9/L or current coagulopathy (most recent INR > 1.5, not due to warfarin)
• Active peptic ulcer disease
• Anticipated need for invasive intervention within next 2 weeks
• Taking warfarin for an indication other than access prophylaxis
• Allergic to, or intolerant of, warfarin
• Pregnant
• Woman of child-bearing age who has not agreed to use an adequate method of birth control for the duration of the study
• Catheter likely needed for 2 weeks or less
• Patient previously took part in the study
• Patient has known aortic aneurysm of 6cm or greater
• Patients nephrologist has refused consent
• Patient has refused consent