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CP-085 VKORC1 in the selection of oral anticoagulant treatment for atrial fibrillation patients
  1. E Jimenez-Varo,
  2. M Cañadas-Garre,
  3. MA Calleja Hernández
  1. Hospital Universitario Virgen de Las Nieves, Pharmacogenetic Unit, Granada, Spain


Background Vitamin K antagonists (VKAs) remain the oral anticoagulant most prescribed for treatment and prevention of thrombotic disorders in atrial fibrillation (AF), despite the recent appearance of the new oral anticoagulants dabigatran, rivaroxaban and apixaban (NOACs). NOACs represent the alternative for some special cases (hypersensitivity or contraindication to VKAs; poor INR (International Normalised Ratio) control or unavailability for INR control). VKORC1-rs9923231 gene polymorphism is related to a longer time to achieve stability, higher risk of over-anticoagulation in the first months of treatment and lower doses of VKAs compared to wild-type patients, therefore exposing these patients to a higher risk of adverse reactions.

Purpose To evaluate the association of VKORC1-TT genotype with the change from VKA to NOAC treatment due to poor INR control at Complejo Hospitalario de Granada.

Materials and Methods Retrospective Cohort study. Patients diagnosed with AF on oral anticoagulant treatment VKORC1-rs9923231 genotype was compared between patients treated with acenocoumarol who achieved a stable dose after a minimum period of seven months and patients who were switched to NOACs after pretreatment with acenocoumarol due to poor INR control Cohorts were defined by VKORC1 TT-genotype Genotyping was performed by Polymerase Chain Reaction - Restriction Fragment Length Polymorphism for VKORC1-rs9923231.

Results Seventy-nine patients fulfilled the inclusion criteria in total. Seventy-one had achieved stable doses with acenocoumarol (89.9%; 71/79) and 8 had been switched to NOACs (10.1%; 8/79). VKORC1-TT genotype was present in 13 patients, 4 switched to NOACs due to poor INR control (30.8%; 4/13). The VKORC1-C allele was present in 66 patients, 4 changed to NOACs (6.1%; 4/66). Relative risk for switching to NOACs was 5.1 (1.5-17.8; p = 0.022).

Conclusions Long-term oral anticoagulant treatment in AF patients should be selected on the basis of the VKORC1-TT genotype, since they are more likely to need NOACs.

No conflict of interest.

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