Laboratory Assesment Of The Anticoagulant Effect Of The Direct Oral Anticoagulants

Direct oral anticoagulants (DOAC) were developed as an alternative to vitamin K antagonists (VKA) and the most commonly used VKA - warfarin, that was the only available class of oral anticoagulants for a long time. As more and more clinical trials regarding the efficacy and safety of DOAC are completed, they are more often included into the guidelines of the most influential medical organisations and are more oft en prescribed by physicians for treatment and prevention of a diverse range of thrombotic and thromboembolic events. These new agents have predictable pharmacokinetics and pharmacodynamics, therefore routine coagulation monitoring is unnecessary. However, there are still some situations when the measurement of their anticoagulative effect would be helpful in making treatment decisions, such as reconsidering the dosage of a DOAC, considering cessation of treatment or possibility to perform invasive procedures, etc. The coagulation assays that are used to monitor vitamin K antagonists or heparin and its' derivatives may not always accurately reflect the anticoagulant activity of DOAC, therefore specialized assays for DOAC were developed. In this article our aims were to identify situattions in which assessment of anticoagulant effect may be helpful, to describe the effects of DOAC on the various most commonly used coagulation tests, to review the specialized coagulation assays that have been developed to assess the effects of the DOAC and to provide clinical recommendations on the evaluation of coagulation testing results. In addition, we discuss other laboratory tests that are needed for baseline check-up and follow up of the patient. We also point out clinical guide lines for antithrombotic therapy with DOAC, compare DOAC with VKA and provide the results of clinical trials that were carried out to evaluate the efficacy and safety of DOAC.