Anticoagulant therapy in Japanese patients with mechanical mitral valves.
There are no guidelines for the optimal therapeutic range of anticoagulant therapy in Japanese patients with mechanical heart valves. A total of 214 patients were followed retrospectively after mitral mechanical valve replacement (mean duration of follow-up, 4.8 years; total duration of follow-up, 1,027 patient-years). The target range of the international normalized ratio (INR) for oral anticoagulation was between 1.5 and 2.5. For all patients 10,416 measurements of the INR were obtained during the follow-up period and approximately 76% of the intensity measurements were within the target range. Thromboembolism occurred in 8 patients (0.8 per 100 patient-years) and major bleeding in 5 patients (0.5 per 100 patient-years). There was no correlation between the distribution of the INR and the occurrence of thromboembolic or bleeding complications. In the univariate analysis of the various risk factors, patients who had a tilting valve or did not receive antiplatelet therapy had an increased risk of thromboembolism. However, there were no risk factors with respect to bleeding complications. A target range of 1.5 to 2.5 INR appears to be the optimal range and is safe for thromboembolism or bleeding complications. Thromboembolism may be reduced by additional antiplatelet therapy, and a tilting valve needs more intense anticoagulation.
Department of Cardiovascular Surgery, Tenri Hospital, Japan.
Katsuhiko
K
Matsuyama
Masahiko
M
Matsumoto
Takaaki
T
Sugita
Junichiro
J
Nishizawa
Kazunori
K
Yoshida
Yoshiyuki
Y
Tokuda
Takehiko
T
Matsuo
D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000925:Anticoagulants / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006470:Hemorrhage / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D015994:Incidence; D007564:Japan; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve; D012189:Retrospective Studies; D012307:Risk Factors; D013923:Thromboembolism / Q000209:etiology / Q000517:prevention & control
D000925:Anticoagulants