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Vitamin K antagonists and emergencies

Lapostolle, Frédérica; Siguret, Virginieb,c; Martin, Anne-Célined,e,g; Pailleret, Claired,e,f; Vigué, Bernardh; Zerbib, Yvesi,j; Tazarourte, Karimk,l

European Journal of Emergency Medicine: December 2018 - Volume 25 - Issue 6 - p 378–386
doi: 10.1097/MEJ.0000000000000541
REVIEW ARTICLE

The recent emergence of ‘non-VKA’ oral anticoagulants may have led to some forgetting that vitamin K antagonists (VKA) are by far the most widely prescribed oral anticoagulants worldwide. Consequently, we decided to summarize the information available on them. This paper presents the problems facing emergency physicians confronted with patients on VKAs in 10 points, from pharmacological data to emergency management. Vitamin K antagonists remain preferable in many situations including in the elderly, in patients with extreme body weights, severe chronic kidney or liver disease or valvular heart disease, and in patients taking VKAs with well-controlled international normalized ratios (INRs). Given the way VKAs work, a stable anticoagulant state can only be achieved at the earliest 5 days after starting therapy. The induction phase of VKA treatment is associated with the highest risk of bleeding; validated algorithms based on INR values have to be followed. VKA asymptomatic overdoses and ‘non-severe’ hemorrhage are managed by omitting a dose or stopping treatment plus administering vitamin K depending on the INR. Major bleeding is managed using a VKA reversal strategy. A prothrombin complex concentrate infusion plus vitamin K is preferred to rapidly achieve an INR of up to 1.5 and maintain a normal coagulation profile. The INR must be measured 30 min after the infusion. Before an invasive procedure, if an INR of less than 1.5 (<1.3 in neurosurgery) is required, it can be achieved by combining prothrombin complex concentrate and vitamin K. A well-codified strategy is essential for managing patients requiring emergency invasive procedures or presenting bleeding complications.

aSAMU 93, UF Recherche-Enseignement-Qualité, Université Paris 13, Inserm U942, Hôpital Avicenne, Bobigny

bINSERM UMR-S1140, Université Paris Descartes, Sorbonne Paris Cité

cService d’hématologie biologique, Hôpital Lariboisière (AP-HP)

dINSERM UMR-S1140, Faculté de Pharmacie

eUniversité Paris Descartes, Sorbonne Paris Cité

fAP-HP, Hôpital Cochin, Paris

gHôpital d’Instruction des Armées Percy, Service de Cardiologie, Clamart

hAPHP, département d’anesthésie-Réanimation, CHU de Bicêtre, Le Kremlin Bicêtre

iEA 4148 S2HEP

jCUMG/DMG, Faculté de médecine Lyon Est, Université Claude Bernard Lyon 1

kEmergency Department, Edouard Herriot Universitary Hospital, Hospices Civils de Lyon

lEA 7425 HESPER UCLB Lyon 1, Lyon, France

Correspondence to Frédéric Lapostolle, PhD, SAMU 93, 93009 Bobigny, France Tel: +33 148 964 454; fax: + 33 148 964 493; e-mail: frederic.lapostolle@avc.aphp.fr

Received July 14, 2017

Accepted November 28, 2017

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.