Pharmacodynamics of Oral Anticoagulants in Patients With Atrial Fibrillation in the Acute Period of Ischemic Stroke

Abstract

Background. Every fifth ischemic stroke is caused by a patient’s history of atrial fibrillation. Nowadays, direct and indirect oral anticoagulants are widely used to prevent thromboembolic complications in patients with atrial fibrillation. However, despite the prescription of this group of drugs, every year 1–2% of patients with atrial fibrillation have an ischemic stroke. In this situation, a number of questions take rise: if it is possible to carry out thrombolytic therapy in the patients who have been taking anticoagulants; if it is worth resuming anticoagulant therapy after a stroke; when exactly this should be done; and what drugs should be used to prevent another stroke.The aim of this review was to summarize the available clinical guidelines and research results on the study of the anticoagu- lant therapy characteristics in patients with atrial fibrillation after an ischemic stroke.Materials and methods. For this review, the information presented in the scientific literature from open and available sourc- es, has been used. The information had been placed in the following electronic databases: PubMed, Scopus, Web of Sci- ence Core Collection, Cochrane Library, ClinicalTrials.gov; Elibrary, Cyberleninka, Google Academy. The covering period was 1997–2020. The search queries were: “ischemic stroke + atrial fibrillation + anticoagulants”; “ischemic stroke + atrial fibrillation + direct oral coagulants” and “atrial fibrillation + ischemic stroke + warfarin” in both Russian and English equivalents.Results and conclusion. Currently, the problem of the use of anticoagulants for the prevention of recurrent thromboembolic complications in patients with AF in the acute period of a stroke, is studied insufficiently. The difficulties are caused by the delivery of TLT in the patients who have been taking DOACs, first of all, due to the impossibility of an accurate assessment of the hemostasis state because of the unavailability of routine specific tests; and second, as a result of the lack of registered antidotes for most drugs, and their high costs. Besides, there are no RCTs dedicated to the study of the optimal time for the resumption or initiation of anticoagulant therapy in the acute period of an IS, and the optimal drugs for this group of patients. Most of the existing recommendations on these aspects, are based on the consensus of experts, and this fact indicates the need for further research in the area under review.