1.
Impact of genetic and clinical factors on warfarin therapy in patients early after heart valve replacement surgery.
Li, B, Liu, R, Wang, C, Ren, C, Zhang, S, Zhang, F, Zhang, J, Liu, S, Wei, Y, Liu, W, et al
European journal of clinical pharmacology. 2019;(12):1685-1693
Abstract
PURPOSE Factors influencing responsiveness to warfarin at treatment onset time were not well identified in Chinese patients undergoing heart valve replacement. We sought to select the most relevant factors that associated with patient response to warfarin early after heart valve surgery. METHODS In this observational study, 289 patients starting warfarin therapy early after heart valve replacement surgery were enrolled. CYP2C9 *1, *2, *3, and *5; VKORC1-1639 G>A, CYP4F2 V433M, and GGCX rs11676382 genotypes; clinical characteristics, response to therapy, and bleeding and thrombosis events were collected. The primary outcomes were the time to the first INR equal to or more than lower limit of therapeutic range and the warfarin dose requirements. Stepwise multiple linear regression was performed to develop a dosing algorithm to predict the warfarin dose requirements. RESULTS The results of univariate analysis showed lone VKORC1-1639 G>A, CYP2C9 *1/*3, cefazolin, cefoperazone-sulbactam, increased BMI, Δhemoglobin, and white blood cell count could significantly affect patient responsiveness to warfarin in the initial period of anticoagulation. Multivariate analysis resulted in an equation: Accumulated warfarin doses (mg) = 17.068 VKORC1-1639 G>A - 4.261 hypertension + 0.593 BMI - 0.115 age - 4.852 CYP2C9 *1/*3 - 2.617 cefazolin - 4.902 cefoperazone-sulbactam - 4.537, which could explain 40.2% of the variability in warfarin dose needed to reach the first INR equal to or more than lower limit of therapeutic range. CONCLUSIONS Both genetic and clinical factors contributed to anticoagulation effect of warfarin in the initial period of treatment. Our findings could provide a basis for the personalized management of warfarin use in the early stage of anticoagulation in northern Chinese patients.
2.
The influence of VKORC1 gene polymorphism on warfarin maintenance dosage in pediatric patients: A systematic review and meta-analysis.
Zhang, J, Tian, L, Zhang, Y, Shen, J
Thrombosis research. 2015;(5):955-61
Abstract
INTRODUCTION Warfarin is the most commonly used oral anticoagulant, however, there are large interindividual variations in dose responses. Genetic polymorphisms in CYP2C9, VKORC1 and CYP4F2 have been shown to play an important role in variations in the warfarin maintenance dose in adults, but their effects in children remain unclear. We aimed to investigate the effect of VKORC1 polymorphism on warfarin dosage in pediatric patients by meta-analysis. MATERIALS AND METHODS Using strict inclusion and exclusion criteria, we searched PubMed, EMBASE, Cochrane library, Chinese Biomedical Literature Database, CNKI and ChainInfo from 2004 to Mach 17th, 2015. The relationship between warfarin dose and two single nucleotide polymorphisms of the VKORC1 gene (at positions -1639 and 1173) were analyzed using Revman version 5.2.3 software. RESULTS AND CONCLUSIONS Eight studies were included in the meta-analysis, involving 610 pediatric patients. Patients that were VKORC1 -1639 GA, AA or A carriers required significantly lower warfarin dosage than GG carriers (the weighted mean difference in warfarin dose ranged from -26% to -50%). Additionally, the age of the patient and indication of warfarin (i.e. Fontan procedure) significantly affected warfarin dosage, but changes in the target international normalized ratio range had no effect. On the other hand, VKORC1 1173 polymorphisms showed no significant effect on warfarin dosage, which differs from adult patients. In conclusion, we found that VKORC1 -1639 gene polymorphisms have a moderate effect on warfarin dosage in pediatric patients, but clinical characteristics such as age and indication of warfarin also play an important role.