EFFICACY OF ANTICOAGULATION WITH VITAMIN K ANTAGONISTS IN ACUT STROKE PATIENTS WITH ATRIAL FIBRILLATION - HUNGARIAN RESULTS

Background and objective - An estimated 20% of ischemic strokes are of cardiogenic origin, half of which is associated with atrial fibrillation (AF). Anticoagulation treatment of,patients with this arrhythmia reduces their risk of stroke. Effectiveness and safety of oral anticoagulant therapy with vitamin K antagonists (VKA) is limited, however, by their well-known narrow therapeutic window and the substantial inter- and intraindividual variability of INR values depending on genetic and dietary factors as well as drug interactions. Our objective was to evaluate the prevalence of adequate anticoagulation and the level of anticoagulant effect actually achieved among patients with AF hospitalized for acute stroke. Methods - Patients with AF admitted to our hospital ward in 2012 for acute stroke (n=226) were included in the analysis. Using descriptive statistics, relevant clinical and therapeutic characteristics of the patients were assessed, with special reference to the INR values on admission (among patients with known AF), and the clinical outcomes. Results - Of the study cohort, 170 patients had a diagnosis of AF before the admission for stroke, but 47% of them did not take anticoagulants. Patients who suffered stroke while on anticoagulants (83 on VKA, 7 on low-molecular-weight heparins), were in most cases (75%) out of the therapeutic INR range, typically undertreated (INR<2). Overall, inadequate or completely absent anticoagulation was documented in 81% of the stroke cases occurring in patients with known AF. Of the entire study cohort, 41% was discharged home, 34% required continued institutional care, and 25% died. Conclusions - The inadequacy or lack of anticoagulation was observed in the vast majority of acute strokes in patients with known AF. These cases are often related to the well-documented limitations of VKA therapy in terms of its safety, tolerability and/or practical aspects. To prevent them, important changes are warranted in the anticoagulation practice, including the closer control of VKA therapy and the broader use of new oral anticoagulants.