INTRODUCTION. Atrial fibrillation (AF) is the most common long-term arrhythmia and represents one of the main public health problems primarily due to the aging of the general population, in which this arrhythmia occurs more often and causes thromboembolic stroke. Cardioembolic stroke associated with AF is usually severe, highly recurrent, and often fatal or with permanent disability of specific stroke risk factors/modifiers. Common risk factors are summarized in a risk factor-based clinical score called the CHA2DS2-VASc Score. Poor INR control increases the risk of both thromboembolic and hemorrhagic complications, and the optimal balance between the benefits and risks of using oral VKAs is achieved when the TTR, or time in the therapeutic range, is ≥ 70% [9]. We present the case of a female patient that confirms the importance of oral anticoagulant therapy when the INR is in the therapeutic range between 2-3, in the largest number of measurements in the successful prevention of recurrent thromboembolic complications during a 14-year follow-up. CASE REPORT: We present a 60-year-old MD patient who first came to the Office of Internal Medicine "Dr. Bastać" in 2008 due to a feeling of instability and heart palpitations. Due to grade II hypertension, which is not well regulated, she has been taking antihypertensive therapy for the past two years, treats elevated cholesterol with statins, and states that in two years and a year before her first examination at the Office of Internal Medicine "Dr. Bastać", she had two minor strokes verified by MSCT of the endocranium. In our patient, a high CHA2DS2-VASc score of 4 was calculated (hypertension, female gender and previous stroke) and the estimated annual risk for stroke is 9.27% (TABLE 2). Her bleeding risk - HAS BLED Score is moderate and is 2 (hypertension, CVI). Based on CHA2DS2-VASc, the risk of adverse thromboembolic events is high and requires the introduction of oral anticoagulant therapy. The patient in therapy receives acenocoumarol according to the scheme so that the value of PT/INR is between 2.0 and 3.0. Good anticoagulation is defined as having 3 to 4 PT/INR values in the therapeutic range (similar to TTR 50 to 60% of the time), while poor anticoagulation is: 0-2 measured INR values in the therapeutic range (TTR <50%) [3]. In our patient, the TTR is about 70%, which represents excellent anticoagulation. During 14 years of monitoring for three months, as well as at the recent control on 04/29/2022. the patient feels well, with no new thromboembolic complications and no bleeding episodes. CONCLUSION. Antithrombotic therapy with vitamin K antagonists can achieve good anticoagulation and long-term successful prevention of repeated cardioembolic strokes in patients with atrial fibrillation. We emphasize the need for highly motivated patients to regularly monitor the level of anticoagulation via INR and the full engagement of the prescribing physician. In this case, we emphasize the frequent problem of delays in the introduction of anticoagulation therapy in atrial fibrillation. Stroke prevention is the cornerstone of care for patients with atrial fibrillation.
