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Comparison of the efficacy and safety profiles of intravenous vitamin K and fresh frozen plasma as treatment of warfarin-related over-anticoagulation in patients with mechanical heart valves
Yiu KH, Siu CW, Jim MH, Tse HF, Fan K, Chau MC, Chow WH
The American Journal of Cardiology. 2006;97((3):):409-11.
Abstract
Patients on warfarin for mechanical heart valves are at increased risk for thromboembolic events and intracranial hemmorhage. In current guidelines, a low dose of vitamin K is the recommended treatment for moderate over-anticoagulation based on studies in which only minority patients participating had mechanical heart valves. We performed a randomized controlled trial to compare the efficacy and safety profile of low-dose intravenous vitamin K and fresh frozen plasma (FFP) for patients with mechanical heart valves and mild to moderate over-anticoagulation (international normalized ratio [INR] 4 to 7). In a 24-month period, we randomized 102 patients to (1) vitamin K or (2) FFP. The baseline INR at presentation between the vitamin K group and the FFP group was 4. 61 +/- 0. 007 vs 4. 78 +/- 0. 07 (p = 0. 11). Six hours after treatment, patients in the FFP group had a significantly lower mean INR compared with the vitamin K group (2. 75 +/- 0. 06 vs 3. 44 +/- 0. 10, p = 0. 01). No patient in both groups had over-correction (INR < 2). One week later, there was no significant difference in mean INR between both groups (2. 7 +/- 0. 11 vs 2. 56 +/- 0. 12, p = 0. 41). Fifty-eight percent of patients in the FFP group and 51% in the vitamin K group had an INR within the target range. There were no adverse reactions or outcomes in both groups. In conclusion, intravenous low-dose vitamin K is a safe alternative to FFP infusion for warfarin overdose in patients with mechanical heart valves.