Effects of CYP2C9 genetic polymorphisms on response to warfarin during initial anticoagulation in Chinese patients with mechanical heart valve replacement

Objective To evaluate the effects of CYP2C9 genetic polymorphisms on response to warfarin during initial anticoagulation in Chinese patients with mechanical heart valve replacement.Methods In 254 Chinese valve replacement patients starting warfarin therapy,the CYP2C9 genotypes(CYP2C9*1,*2,and *3) were assessed.The study outcomes included the time to the first International Normalized Ratio(INR) reach the therapeutic range,the total warfarin doses in initial 5 days,and whether INR within the therapeutic range in the day 6.Results Compared with patients with the *1/*1 genotype,patients with the *2 or *3 genotype of CYP2C9 had the same time to the first INR reach the therapeutic range(P=0.933) and no difference in total warfarin doses in initial 5 days(P=0.669).However,the CYP2C9 genotype was a significant predictor of INR within the therapeutic range in the day 6.Conclusion CYP2C9 genetic polymorphisms only affected INR within the therapeutic range in the day 6 in Chinese patients with mechanical heart valve replacement.