Unite d’Hemostase Clinique, Hospices Civils de Lyon, Lyon, France
Yesim Dargaud is a Professor in the Clinical Hemostasis Unit and Hemophilia Comprehensive Care Centre at Lyon University Hospitals, France. She is a member of the French Reference Centre for Hemophilia and Other Inherited Rare Bleeding Disorders. Yesim Dargaud's research interests focus on inherited bleeding disorders, novel therapeutic approaches of hemophilia with inhibitors, molecular and cellular biology of factor IX. She has a particular interest in the current and future approaches for personalized management of patients with haemophilia.
Case Report
Warfarin Hypersensitivity in a Patient with Mechanical Valve: A Real Challenge for the Management of Life-Long Anticoagulant Treatment
Author(s): Melanie Daniel, Yohann Jourdy, Mathilde Fretigny and Yesim Dargaud*
Bleeding is the most common adverse effect of vitamin K antagonist (VKA) therapy. We describe the case of a patient who reported severe spontaneous bleeding episodes after starting treatment with warfarin-based anticoagulants following a mechanical mitral valve implant, although the international normalized ratio was within the therapeutic range. Exhaustive coagulation testing detected very low plasma factor IX (FIX) activity (FIX:C= 5 IU/dL) that increased to normal values(89 IU/dL) upon warfarin withdrawal. F9 gene sequencing revealed the presence of the p.Ala37Thr missense variation in the pro-peptide coding region. This substitution was previously associated with FIX hypersensitivity to warfarin. Patients with this variation are usually switched from VKA to direct oral anticoagulants or heparin. However, the current guidelines recommend warfarin for all patients with mechanical va.. View more»