title: 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.
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.
authors.affiliation: Cardiology Division, Department of Medicine, Queen Mary Hospital, Hong Kong, China.
authors.forename: Kai-Hang
authors.initials: KH
authors.lastname: Yiu
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
authors.forename: Man-Hong
authors.initials: MH
authors.lastname: Jim
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Katherine
authors.initials: K
authors.lastname: Fan
authors.forename: Mo-Chee
authors.initials: MC
authors.lastname: Chau
authors.forename: Wing Hing
authors.initials: WH
authors.lastname: Chow
mesh_terms: D000925:Anticoagulants / Q000009:adverse effects*; D001778:Blood Coagulation Disorders / Q000139:chemically induced* / Q000188:drug therapy*; D016913:Blood Component Transfusion; D003029:Coagulants / Q000008:administration & dosage*; D005260:Female; D006349:Heart Valve Diseases / Q000601:surgery; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D007262:Infusions, Intravenous; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D010949:Plasma; D011446:Prospective Studies; D016896:Treatment Outcome; D014812:Vitamin K / Q000008:administration & dosage*; D014859:Warfarin / Q000009:adverse effects*
chemical_list: D000925:Anticoagulants; D003029:Coagulants; D014812:Vitamin K; D014859:Warfarin