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[Anticoagulation therapy after mechanical prosthetic heart valve replacement with special reference to international
Insights
Warfarin anticoagulation after valve replacement showed fewer complications at a lower INR target (2.53) for Japanese patients. This adjusted anticoagulant therapy proved more suitable than the standard ACCP guidelines.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Pharmacology
Context:
- Anticoagulation management is critical post-heart valve replacement surgery.
- Warfarin is a common anticoagulant, but optimal target ranges may vary by patient population.
- Previous guidelines recommended higher International Normalized Ratio (INR) targets.
Purpose:
- To compare warfarin efficacy and complications after mitral valve replacement (MVR) and aortic valve replacement (AVR).
- To evaluate the suitability of adjusted INR targets for Japanese patients undergoing valve replacement.
Summary:
- This study analyzed 98 patients (57 MVR, 41 AVR) receiving warfarin post-valve replacement.
- INR targets were adjusted to 2.3-3.1 in 1991 and 2.1-2.8 in 1992, with mean INRs of 2.75 and 2.53 respectively.
- Complications, including bleeding and thromboembolism, were monitored, with no adverse events in 1992.
Impact:
- Findings suggest a lower mean INR of 2.53 may be more appropriate for Japanese patients than the ACCP-recommended 3-4.5.
- This research could inform personalized anticoagulation strategies for specific ethnic groups after prosthetic valve implantation.
Abstract:
We compared the efficacy and complications of anticoagulation with warfarin in 98 patients after isolated mitral valve replacement (MVR 57 pts) and isolated aortic valve replacement (AVR 41 pts). Fifty Medtronic-Hall valves, 33 St. Jude Medical valves, 9 Björg-Shiley valves and 6 other valves were used. In 1991, we made our control standard of prothrombin-time (%) between 25% and 35% (INR 2.3-3.1) and in 1992, between 30% and 40% (INR 2.1-2.8), although INR recommended by ACCP in 1988 was 3 to 4.5. In 1991, mean PT (%) was 31.2% and mean INR was 2.75 in our patients. In 1992, mean PT (%) was 35.0% and mean INR was 2.53. In 1991, we experienced bleeding episodes in three patients and thromboembolism in one case. In 1992, no complication occurred. We conclude that anticoagulant therapy of mean INR 2.53 seemed to be more suitable for Japanese patients than the ACCP standard.