Abstract
After a valve replacement surgery, most patients especially those with mechanical heart valve are required to be on anticoagulant therapy with vitamin K antagonist. As the treatment has a narrow therapeutic index between thromboembolism due to insufficient anticoagulation and hemorrhage due to excessive anticoagulation, patients are required to have their INRs routine monitored to minimize complication. Many studies have shown that VKORC1-1639 G>A (rs9923231) and CYP2C9*2*3 (rs1799853)(rs1057910) gene polymorphisms affect the dosage and effects of anticoagulants. We performed a retrospective longitudinal study to determine if there is association between VKORC1 gene polymorphism and adverse events in anticoagulated patients after artificial heart valve replacement surgery, monitored in Vietnam National Heart Institute Bach Mai hospital.
Our study results show that patients with genotype VKORC1-1639 homozygous dominant AA had significantly lower anticuagulation dose compared with heterozygous AG and homozygous recessive. The AA genotype group also had an increased risk of thrombosis (the number of INR index tests < 1,5) and the higher incidence of bleeding events during treatment. Information VKORC1 variants may be useful to identify individualized oral anticoagulant treatmen for each patient, improve management and quality of VKA anticoagulation control.