Clinical Significance Of Individualized Warfarin Anticoagulant Therapy Based On Pharmacogenomics In Patients After Cardiac Valve Replacement

Objective:The patients with heart value replacement is difficult to predict the level of anticoagulation in response to a fixed-dose regimen of warfarin. We prospectively compared the effect of genotype-guided dosing with that of standard dosing on anticoagulation control in patients starting warfarin therapy.Methods:We involved 60 patients with heart value mechanical replacement, with 30 assigned to control group and 30 assigned to genotype group. For patients assigned to the genotype-guided group, warfarin doses were prescribed according to pharmacogenetic-based algorithms for the first 3 days. Patients in the control(standard dosing) group received a 3-day 3mg warfarin regimen. After the initiation period, the treatment of all patients was managed according to international normalized ratio(INR). The primary outcome measure was the percentage of time in the therapeutic range of 1.8 to 2.5 for the INR during the first 2 months after warfarin initiation.Results:A total of 56 patients complete follow-up, with 27 genotype group and 29 control group.The mean percentage of time in the therapeutic range was 76.72% in the genotype-guided group as compared with 59.23% in the control group( 95% confidence interval, 8.6 to 26.4; P<0.001).The median time to reach a therapeutic INR was 21 days in the genotype-guided group as compared with 27 days in the control group. There were no significant difference in percentage of insufficient anticoagulation, percentage of excessive anticoagulation,bleeding events andthromboembolic events.Conclusions:Parmacogenetic-based dosing was better than standard dosing during the initiation of warfarin therapy in patients with heart value replacement.