WARFARIN AND ITS IMPORTANCE IN THE ERA OF NEW ORAL ANTICOAGULANTS. ISSUES OF MONITORING THE EFFECTIVENESS AND SAFETY OF TREATMENT

Abstract

Oral anticoagulant (OAC) therapy is currently gaining special importance due to the significant spread of atrial fibrillation (AF) in the population (especially in older age groups). The use of OAC in AF has an extensive evidence base, which confirms a significant decrease in the number of strokes and total mortality in the context of anticoagulation therapy (ACT) in AF. Currently, the "gold standard" of the OAC is warfarin, which has proved effectiveness in all categories of patients with AF. A whole group of new OAC (NOAC) also appeared. In Russia, dabigatran, rivaroxaban and apixaban have been registered. All NOAC were studied in randomized clinical trials (RCTs) in comparison with warfarin, mainly in patients with non-valvular AF, therefore, in valvular AF, as well as in patients with severe renal failure, warfarin remains the drug of choice. Advantages of warfarin in comparison with NOAC are the presence of known antidote and standardized indicator of the efficacy and safety of the anticoagulation therapy – International Normalized Ratio (INR), as well as low price of the drug. The leading problem in the treatment of warfarin is the complexity and, at the same time, a strong need to maintain INR within the therapeutic "window" of at least 60% of the treatment time. Obviously, the optimal solution to this problem is the possibility of self-testing of this indicator by the patient himself and, probably, the ability to adjust the dosage of warfarin independently, to achieve the necessary values of INR (self-management) or titrate the dose with the help of a medical consultation by phone (self-monitoring). To date, several devices have been developed for self-monitoring of anticoagulation therapy – coagulometers. Their use leads to a decrease in the number of thromboembolic complications, and from the results of some RCTs – to a decrease in the number of large bleedings and total mortality, and to improve the quality of life of AF patients who need constant anticoagulation therapy. The high economic efficiency of using coagulometers has also been confirmed. Coagulometer CoaguChek (Roche, Switzerland) has the largest evidence base for self-monitoring of INR and its impact on the efficacy and safety of anticoagulation therapy.

Keywords

• oral anticoagulants
• warfarin
• international normalized ratio
• self-testing
• coagulometer