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Fixed minidose versus-adjusted low-dose warfarin after total joint arthroplasty: a randomized prospective study
M J Vives1, W J Hozack, P F Sharkey
1Department of Orthopaedic Surgery, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
The Journal of Arthroplasty
|December 12, 2001
Summary
Fixed low-dose warfarin may simplify prophylaxis after joint replacement but still requires monitoring. Some patients achieve anticoagulation levels risking bleeding complications, necessitating continued laboratory checks.
Area of Science:
- Orthopedic Surgery
- Pharmacology
- Clinical Medicine
Background:
- Adjusted low-dose warfarin use is limited by monitoring needs and bleeding risks.
- Further dose reduction could eliminate monitoring and decrease complications.
Purpose of the Study:
- To evaluate the safety and efficacy of a fixed minidose warfarin regimen compared to adjusted low-dose warfarin in primary total joint arthroplasty patients.
- To determine if laboratory monitoring can be eliminated with a fixed warfarin dose.
Main Methods:
- Prospective randomized trial of 245 patients undergoing primary total joint arthroplasty.
- Two groups: adjusted low-dose warfarin (INR 1.4-1.8) and fixed minidose warfarin (2 mg daily).
- Prophylaxis for 6 weeks with twice-weekly monitoring; follow-up for bleeding and thromboembolic events.
Main Results:
- No significant difference in thromboembolic or bleeding event rates between groups.
- 8% of patients on fixed-dose warfarin had an international normalized ratio (INR) >3.1, requiring dose reduction.
- A subset of patients on fixed-dose warfarin achieved moderate anticoagulation, posing a bleeding risk.
Conclusions:
- A fixed minidose warfarin protocol may simplify outpatient prophylaxis but still requires intermittent laboratory monitoring.
- Even with a fixed dose, some patients achieve therapeutic anticoagulation, necessitating monitoring to mitigate bleeding risks.
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