Finding a new balance: from vitamin K antagonists to Direct Oral Anticoagulants

Abstract

Thrombosis is the process of a blood clot forming inside a blood vessel, obstructing blood flow. Oral anticoagulant therapy is prescribed for treatment and prevention of thrombo-embolic diseases. The most important side effect of anticoagulants is the occurrence of bleeding. For decades, vitamin K antagonists (VKA) were the cornerstone of treatment, which required routine monitoring of the International Normalized Ratio (INR). After the introduction of Direct Oral Anticoagulants (DOAC), which currently do not require routine concentration monitoring, patients had to decide whether to remain with VKA or switch to DOAC. The first part of this thesis focuses on the evaluation of VKA treatment and the transition of VKA to DOAC. As the incidence of major bleeding with DOAC is still 2-4% there is room for improvement in their management. The second part this thesis evaluates the variability of DOAC plasma concentrations and how DOAC therapy may be improved.