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Introduction. Lengthening the period of direct oral anticoagulant (DOAC) withdrawal before intervention is not allowed. Chronic kidney disease (CKD), impaired liver function, extremely low or high body mass, chronic heart failure (CHF), and age > 90 years can increase blood DOAC levels. DOAC therapy does not require routine laboratory monitoring. However, there are coagulation tests that can be used to detect the presence of a drug in blood. Duration of DOAC discontinuation and the appropriateness of assessing residual anticoagulant concentrations before intervention with a high bleeding risk in a special category of patients is to be defined.Aim. To measure residual concentrations of anticoagulants and their association with perioperative bleeding risk in patients with AF using DOACs in blood samples collected immediately before TAVI.Materials and methods. The 94 patients with atrial fibrillation (AF) included in the study were characterized by senile age, a high risk of thromboembolic complication (ТС), many comorbidities, and a high prevalence of senile asthenia. The apixaban and rivaroxaban concentrations were measured according to the value of anti-Xa activity and control plasmas with normal levels of coagulation factors (Diagnostica Stago, France).Results. The median time of DOAC withdrawal before TAVI was 60 hours [47.5; 72]. However, the DOAC concentration exceeded 30 ng/ml in 1/5 patients (19.2%), and stage 3 or more CKD was more common in these patients. Our study showed the relationship between DOAC concentration and the duration of DOAC withdrawal period. However, the relationship between DOAC concentration and bleeding that occurred in the perioperative period could not be found. Patients with signs of CKD were older and had a lower BMI as compared to patients without CKD.Conclusion. Our data showed the relationship between the DOAC concentration and the duration of DOAC withdrawal period. No relationship was found between DOAC concentrations and bleeding.

This review is devoted to the aspects of anticoagulant therapy in patients with atrial fibrillation in the light of the modern understanding of this type of arrhythmia as a polymorbid continuously developing syndrome. According to experts, the management strategy of this category of patients is based on an integrated assessment, including the risk of stroke, the presence of symptoms, assessment of structural heart disease and mandatory accounting of concomitant pathology. In this approach, the appointment of anticoagulant therapy as a prevention of stroke in a patient with atrial fibrillation is put in the first place. At the same time, experts emphasize the need for a dynamic reassessment of risks, as well as the use of a multidisciplinary team of specialists to make a complex decision. The review summarizes the basic concepts of the integrated approach, describes various variants of clinical scenarios, including aspects of anticoagulant maintenance of cardioversion and catheter ablation, multicomponent therapy after percutaneous coronary intervention. A separate chapter is devoted to modern algorithms of perioperative management of a patient receiving oral anticoagulants, which is based on the stratification of interventions according to the risk of perioperative bleeding and the characteristics of the anticoagulant prescribed to the patient. The place of dabigatran in the primary and secondary prevention of stroke and systemic embolism in patients with atrial fibrillation is described, studies that served as the basis of the evidence base for the use of dabigatran in patients with atrial fibrillation are presented. The data of register observations, meta-analyses devoted to the evaluation of the efficacy and safety of dabigatran in certain categories of patients (elderly patients, patients with chronic heart failure, diabetes mellitus) are presented, which form the basis of decision-making in real clinical practice.

Currently, direct oral anticoagulants (DOACs) should be preferred when prescribing anticoagulant therapy to atrial fibrillation patients because of their lower potential for interactions and risk of bleeding than warfarin. However, in the absence of standardized laboratory tests and a specific antidote (except dabigatran), prescribing and monitoring DOAC therapy remains a challenge for clinicians and patients. The present review focuses on the problems of DOAC laboratory evaluation, indications, and prospects for its use. Routine coagulation tests including activated partial thromboplastin time, prothrombin time and thrombin time are not recommended for DOAC therapy. Currently, there are specific coagulation tests (anti-Xa activity factor determination for apixaban/ rivaroxaban and diluted thrombin time for dabigatran) that allow judging the presence of the drug in the blood. According to current recommendations, these tests should be used only to assess anticoagulant concentrations and not to adjust doses and decide on the timing of withdrawal before invasive intervention. Nevertheless, the issue of determining DOAC concentration during invasive interventions, the need for which only increases with age, is most relevant. Also a possible additional factor that may alter the bioavailability and pharmacokinetics of DOAC and be taken into account in the evaluation of laboratory activity is the presence of chronic renal disease, hepatic insufficiency, low or excess body weight. The use of specific coagulation tests for patients undergoing elective and urgent surgery among special categories of patients (with chronic kidney disease, low or excess body weight, renal failure) is promising.

Introduction. Despite the large evidence base for the use of rivaroxaban, cohort studies are interesting because shows the possibility of anticoagulant therapy in patients with high thromboembolic and bleeding risk and a burden of comorbidity in practice.Aim: to evaluate the efficacy and safety of rivaroxaban therapy in patients with atrial fibrillation in prospective REGATTA registry.Materials and methods. This study is a fragment of a single-center prospective REGATA registry (Registry of Long-term Antithrombotic Therapy (NCT043447187), conducted on the basis of the National Research Center of Cardiology of the Ministry of Health of the Russian Federation. 152 patients with high thromboembolic risk (median CHA2DS2-VASc = 4) received rivaroxaban therapy (median follow-up 1.5 years). The efficacy endpoint was the sum of cardiovascular complications (including cardiovascular death, ischemic stroke, and acute coronary syndrome). The safety endpoint bleedinds BARC types 2-5.Results. The frequency of cardiovascular events (combining cardiovascular death, ischemic stroke and acute coronary syndrome) was 5.8/100 patient-years. The use of a “reduced” dose of rivaroxaban was an independent predictor of the development of fatal cardiovascular complications. The rate of major bleeding was 3.7/100 patient-years, and the rate of clinical relevant bleedings was 19.4 /100 patientyears. The predictors of major/ clinical relevant bleedings were chronic kidney disease with a decrease in creatinine clearance of less than 50 ml/min and the anamneses of major/ clinical relevant bleedings.Conclusion. The main requirement for improving the safety of anticoagulants is follow up, focused in all changes in the cardiovascular and somatic status of the patient during treatment.

This review focuses on some aspects of anticoagulant therapy in the updated clinical guidelines for atrial fibrillation of the European society of cardiology, published in 2020. Atrial fibrillation is a polymorbid continuously developing syndrome, and therefore the treatment strategy is based on a comprehensive assessment of the patient, including the risk of stroke, the presence and severity of symptoms, and an assessment of structural heart disease and comorbidities. The review describes the principles of the proposed integrated approach, abbreviated “ABC pathway”, as reflecting the three main directions of the treatment strategy. According to experts, the clinical picture of AF (i.e. first detected, paroxysmal, persistent, long-term persistent or permanent) should not determine the indications for the appointment of anticoagulant therapy. The CHA2DS2-VASc scale continues to be the basis for stratification of thromboembolic risk. The role of dabigatran in primary and secondary prevention of stroke and systemic embolism in patients with atrial fibrillation is described. Changes in the position of experts regarding the assessment of bleeding risk are highlighted in order to help identify unmodified and eliminate modifiable risk factors for bleeding, as well as to identify AF patients who are potentially at high risk of bleeding for more frequent monitoring and monitoring of their condition. Questions about the use of direct oral anticoagulants in the choice of rhythm control tactics are highlighted separately. The use of dabigatran in patients undergoing cardioversion and catheter ablation is justified. Practical questions about the continuous strategy of anticoagulant therapy during ablation are highlighted separately. Changes related to multicomponent therapy after percutaneous coronary intervention are highlighted. The main measure to improve the safety of combined antithrombotic therapy is to minimize the duration of triple therapy. The updated recommendations supportlimiting the duration of triple antithrombotic therapy to 1 month, and also provide for early discontinuation of aspirin (≤1 week) and continuation of double antithrombotic therapy in cases of uncomplicated stenting and low risk of thrombosis, or when the risk of bleeding exceeds the risk of thrombotic events.

Aim.To analyze the frequency of resumption of anticoagulant therapy (ACT) after major and clinically significant bleeding among AF patients who received oral anticoagulants and were observed in the Department of clinical problems of atherothrombosis from 1999 to 2019 within the retro-prospective register Regata-2, and to search for clinical factors associated with recurrence of hemorrhagic complications among patients who resumed anticoagulant therapy after a bleeding episode. Materials and methods.In cohort study of patients with high-risk AF with absolute indications for ACT we enrolled 290 AF patients (130 women and 160 men) aged 32 to 85 years (the average age was 65.188.89 years). During the follow-up period, 92 patients developed hemorrhagic complications, and 73 of them resumed ACT. 35 of the 73 patients who resumed ACT developed a relapse of major/clinically significant bleeding. Results.The frequency of resuming ACT after the first hemorrhagic complication increased over time from 75% in the period from 19992003 to 90% in the period 20152019. We were not able to establish an exact relationship between the presence of concomitant pathology and the decision to resume the ACT after bleeding. The only reliable reason for refusing to resume the ACT was the patients categorical reluctance. Among patients who had recurrent hemorrhagic complications, the total score on the Charleson comorbidity scale was significantly higher (4.232.01vs3.521.43;p=0.0425). Patients with recurrent bleeding were significantly more likely to suffer from CKD with a decrease in GFR less than 60 ml/min/1.73 sq. m, and also had a history of erosive and ulcerative lesions of the gastrointestinal tract. There was also a significant Association of recurrent bleeding with the use of proton pump inhibitors. Subgroups of patients who switched from warfarin to taking direct oral anticoagulants after the first bleeding and subsequent recurrent bleeding did not differ in basic clinical characteristics from patients without bleeding after changing the anticoagulant. According to multiple regression analysis, NSAIDs showed a tendency to develop a relapse of B/C bleeding on the background of direct oral anticoagulants in patients who underwent GO on the background of warfarin therapy (b=0.4524,p=0.0530). Conclusion.During the 20-year follow-up, the frequency of all major and clinically significant bleeding was 2.6/100 patients-years, the frequency of first bleeding was 5.86/100 patients-years, while the frequency of repeated hemorrhagic complications was 7.06/100 patients-years. Patients with a high thromboembolic risk should receive anticoagulants, provided that the modifiable risk factors for bleeding are carefully corrected.

This review systematizes the currently known data on intracardiac thrombosis. The main nosology leading to left atrial thrombosis is atrial fibrillation, with up to 90% of all trombi forming in the left atrial appendage. The optimal method to diagnose thrombosis is the transesophageal echocardiography. The detection rate of left atrial appendage thrombosis in early studies ranged from 2.5 to 74.7% and dropped to 1-15.2% in the era of oral anticoagulants. However, there is no basis for performing transesophageal echocardiography as a screening examination for all patients with atrial fibrillation, and the CHA2DS2-VASc clinical scale is the guideline for prescribing and selecting antithrombotic therapy. The article presents data on the possibility of lysis of the left atrial appendage thrombosis against the background of oral anticoagulants therapy, which is of practical importance for patients before cardioversion and pulmonary vein ablation. The results of published studies and observations of patients receiving vitamin К antagonists show that 46.3-85% of thrombi are dissolved. The only prospective study to investigate the possibility of left atrial thrombosis lysis in patients with atrial fibrillation or fluttering while taking direct oral anticoagulants was X-TRA, which studied rivaroxaban therapy and showed thrombi dissolution in 41.5% of patients. The frequency of left ventricular thrombosis in patients with acute coronary syndrome with ST segment elevation in the age of reperfusion therapy is about 6-7%, reaching 19.2% in patients with anterior myocardial infarction and reduction of left ventricular ejection fraction. These recommendations indicate that only vitamin К antagonists may be prescribed in patients with left ventricular thrombosis. However, the results of the COMMANDER HF study showing the potential of rivaroxaban to prevent thromboembolic complications in patients with chronic heart failure have laid the foundation for the use of direct oral anticoagulants in left ventricular thrombosis. At present the study of efficacy and safety of apixaban and rivaroxaban in this category of patients is ongoing, but there are no results at present. In most cases, right ventricular thrombosis is part of the development of a pulmonary embolism, and much less often it accompanies right ventricular arrhythmogenic dysplasia or is associated with implantable devices. Anticoagulants are the basis for the treatment of these patients, and the present guidelines allow for moderate and low risk thromboembolism in patients with pulmonary artery thromboembolism, along with parenteral anticoagulants, prescribing immediate oral anticoagulants, giving preference to Xa-factor antagonists or direct thrombin inhibitors.

Aim. To study the predictive value of growth differentiation factor 15 (GDF-15) in patients with atrial fibrillation (AF) after elective percutaneous coronary intervention (PCI).Material and methods. The study included 150 patients (men, 69,3%) with AF receiving direct oral anticoagulants in combination with two (89,3%) or one antiplatelet agent (10,7%) after elective PCI. Median age was 71,0 [interquartile range, 66,0; 77,0] years. The median follow-up was 11,5 months [interquartile range, 8,0; 12,0]. The efficacy endpoint was the sum of cardiovascular events (CVEs), including cardiovascular death, ischemic stroke, venous thromboembolism, peripheral arterial thrombosis, acute coronary syndrome, and the need for emergency PCI. The safety endpoint was considered to be BARC type 2-5 bleeding. Prior to PCI, blood plasma samples were taken from patients to determine GDF-15 and D-dimer by enzyme immunoassay.Results. The incidence of CVEs was 16%. The incidence of BARC type 2-5 bleeding was 24,7%. The median GDF-15 level was 1270,0 pg/ml [953,0; 1778,0]. According to multiple regression, the GDF-15 level is associated with D-dimer (t=3,20; p=0,0018), diabetes (t=3,97; p=0,0001) and SYNTAX score II (t=4,77; p1191 pg/ml (p=0,0076) increases the likelihood of CVE (area under the curve, 0,647; confidence interval (CI), 0,5650,723). According to Kaplan-Meier survival curves, significant differences were found in terms of absence of CVEs during the follow-up period between the groups of patients with a GDF-15 >1191 and those with GDF-15

Russian Society of Cardiology (RSC).With the participation of Russian Scientific Society of Clinical Electrophysiology, Arrhythmology and Cardiac Pacing, Russian Association of Cardiovascular Surgeons.Approved by the Scientific and Practical Council of the Russian Ministry of Health.

Rationale: Thrombosis of the puncture site in the femoral veins is one of the potentially dangerous complications of intracardial catheter interventions associated with thromboembolic risk related to its proximal location. According to the literature, the incidence of symptomatic venous thrombosis (VT) is 1–3%. No special studies on the assessment of risk factors for this complication, its diagnosis and treatment have been conducted.Aim: To study the incidence, risk factors and special aspects of VT diagnosis in patients undergoing intracardial electrophysiological studies (EFI) and/or catheter ablation.Materials and methods: This prospective study included 408 patients (194 men and 214 women, with median age of 51±10.1 years), who were admitted to the hospital with various cardiac rhythm disorders for intracardial EFIs and/or catheter ablations from 2016 to 2018. Before the interventions, in addition to common laboratory and instrumental work-up, all the patients underwent ultrasound duplex scanning (USDS) of the iliac-femoral segment; in 269 patients the level of D-dimer was measured. Latest at 24 hours after the intervention, all patients underwent a control ultrasound scan of the femoral vein puncture site. In case of VT occurrence anticoagulant therapy was started in all patients and they were followed up till complete VT resolution and at least for 3 months (the study endpoint). The VT incidence and its risk factors including the prognostic value of D-dimer levels were evaluated.Results: The VT incidence after catheter interventions was 11.7% (n=48). There was a significant correlation between VT occurrence and such risk factors as diabetes mellitus (p=0.001) and obesity (p500 ng/mL) and subsequent VT development was found (p>0.05). The quartile analysis revealed an association between baseline D-dimer levels exceeding 434 ng/mL (which corresponds to the range of 75 to 100%) and the presence of the following risk factors: age over 65 years (p

The use of modern oral anticoagulants is associated with a significant reduction in the risk of stroke and systemic embolism in patients with atrial fibrillation, and thus with an increase in the life expectancy of patients. That is why multicomponent therapy and perioperative tactics are actual during prolonged anticoagulation, the aspects of which seem to be one of the most difficult from the practical point of view. This clinical observation is an illustration of the management of a patient with atrial fibrillation at high thromboembolic risk who is receiving Rivaroxaban therapy and who has indications for catheter ablation and multicomponent antithrombotic therapy.

Assessment of kidney function is mandatory in all cardiac patients, and patients with atrial fibrillation represent a category of patients with high thrombotic risk, which increases the risk of decreased kidney function during follow-up. Controversial issues of warfarin-associated nephropathy are important today. A prospective 5-year follow-up of 172 patients receiving warfarin therapy showed that 26.7% had the sudden loss of renal function (SLRF) (defined as an annual decline in glomerular filtration rate (GFR) ≥ 3 ml/min/1.73 cm2). Based on the results of the ROC analysis, it was determined that the maximum INR > 3.97 was associated with the SLRF (the area under the curve was 0.649, the sensitivity 56.5%, the specificity 74.6%, p = 0.003), and the maximum INR> 6.0 increased the specificity of the analysis to 96%. The study showed that for patients who had a maximum INR value ≥ 3.97, the mean delta of changes in GFR was negative, and the largest negative dynamics was characteristic for patients with a maximum INR ≥ 6.0. The estimated odd ratio of SLRF confirms the high prognostic significance of the maximum INR value. The maximum INR 3.97-5.9 increased the risk of SLRF by 3.07 times (95% CI 1.5241-6.2017, p = 0.0017), as well as the INR ≥ 6.0 (OR 3.05, 95% CI 1.0073-9.2433, p = 0.0485). The multifactorial discriminant analysis showed that the SLRF predictors against the background of 5-year warfarin therapy included the maximum INR ≥ 3.97 (F = 10.45, p = 0.0014), IHD (F = 8.7, p = 0.0036), diabetic nephropathy (F = 5.29, p = 0.0226) and the CHA2DS2-VASc score ≥ 4 (F = 5.05, p = 0.0258).

Atrial fibrillation (AF) is the most common indication for the long-term oral anticoagulation therapy. For several decades, vitamin K antagonists have been the mainstay of routine clinical practice.A prospective 10-year follow-up of patients with atrial fibrillation receiving warfarin therapy showed that the incidence of all cerebral circulation disorders was 2.59 per 100 patient-years. The warfarin therapy contributed to the prevailing of non-fatal events among the cerebral circulation disorders which occurred during the therapy. The incidence of fatal ischemic strokes was 0.91 per 100 patient-years over the 10-year follow-up study.If the duration of a patient within the target therapeutic range (TTR) was

For patients with atrial fibrillation, long-term oral anticoagulant therapy reduces the risk of ischemic stroke and systemic embolism, while increasing the risk of hemorrhagic complications. To assess the safety of therapy, along with major bleeding, minor and clinically relevant bleeding also should be taken into account. Minor, especially recurrent hemorrhages usually do not provide a reason for discontinuing anticoagulant therapy. The described follow-up demonstrated the absence of major hemorrhage in the patient with recurrent minor hemorrhagic complications against a background of 15-year course of anticoagulant therapy (including 9-year course of dabigatran treatment).

Despite the long-term clinical experience, bleeding remains the greatest danger for patients taking vitamin K antagonists. Moreover, even the presence of risk factors for hemorrhagic complications in a patient should not be the only reason for cancelling anticoagulant therapy. The challenge in assessing the frequency of hemorrhage is primarily explained by different approaches to hemorrhage classification. For patients receiving long-term anticoagulant therapy, along with fatal and life threatening hemorrhages, minor and clinically significant small hemorrhages should be taken into account to assess the safety of treatment. The 15-year prospective follow-up of patients receiving warfarin found that the frequency of all hemorrhagic complications was 8.66/100 patient-years, major hemorrhage — 2.98/100 patient-years, and clinically significant hemorrhage — 2.62/100 patient-years. According to the results of the discriminant analysis, the predictors for the development of major and clinically significant hemorrhagic complications in patients receiving long-term therapy with warfarin are administration of proton pump inhibitors, labile INR during therapy, recurrent minor hemorrhage in history and amiodarone therapy. The 15-year prospective follow-up of patients receiving warfarin demonstrated that minor hemorrhagic complications account for one third of all bleedings and are not associated with the subsequent development of clinically significant and major bleeding in patients. The prospective follow-up also found an increase in the frequency of hemorrhagic complications if one or two antiplatelet agents were added to warfarin therapy. The incidence of major and minor clinically significant hemorrhagic complications during triple antithrombotic therapy was 24/100 patient-years, which was higher than in the warfarin monotherapy subgroups and in the case of combining warfarin with an antiaggregant (4.4 and 8.47%, respectively). The localization of bleeding was analyzed to reveal that in triple antithrombotic therapy the greatest number of bleedings occurred in the upper or lower gastrointestinal tract. The relative risk was calculated to confirm that triple antithrombotic therapy significantly increased the risk of gastrointestinal bleeding by 3.02 times.

In a question-and-answer format, the most critical issues concerning the safety of therapy and management of patients taking dabigatran are considered in the article. Particular attention is paid to the prospects of anticoagulant therapy in patients with comorbidities, as well as interactions between novel oral anticoagulants and other groups of medications, risk assessment of potential complications of therapy.

The safety of anticoagulant therapy is discussed. Warfarin position in prevention of thrombotic complications is analyzed according to the evidence base medicine approach. Possible hemorrhagic complications of warfarin are described and accompanied with clinical cases. Possibility of renewal of anticoagulant therapy in patients after hemorrhagic complications is discussed.

The paper discusses the most common questions regarding the safety of therapy and patronage system in patients who receive warfarin in the question and answer form. Vitamin K antagonists now are the oral anticoagulants that are most commonly used in the actual clinical practice. Despite a large accumulated body of clinical experience, it is not always easy for a doctor to pick the individual dose of warfarin.

Aim. To evaluate efficacy and safety of reduced dose of direct oral anticoagulants (DOACs) as part of triple antithrombotic therapy in AF patients, undergoing elective percutaneous coronary intervention (PCI), and to identify factors, associated with this strategy. Materials and methods. The study is a cohort analysis of AF patients with AF, who successfully underwent elective PCI and assigned DOACs as part of triple antithrombotic therapy (TAT).Influence of a reduced DOACs dose as a part of TAT on the frequency of thecomposite efficacy endpoint (acute coronary syndrome, ischemic stroke, venous thromboembolic events, cardiovascular death and angina pectoris aggravation/need for unplanned PCI) and safety endpoint (hemorrhagic complications BARC types 2-5) were assessed using the Log-Rank criterion. Results. The study included 124 pts (69.4% women, mean aged 69±8.2 years). Themedian total score CHA2DS2-VASc was 5, the median of the Charlson index composed 7. Half (52%) of AF patients with high risk of thrombotic events after elective PCI received reduced-DOACs dose. Median follow up period was 11.0 month. 17 adverse thrombotic events were recorded during this period, BARC 2-5 bleedings occurred in 27 patients. Reduced DOACs doses in AF patients undergoing PCI were associated with significant increase of thrombotic events during follow up period compared to patients received full DOACs doses (0.79 vs 0.93, Log-Rank p=0.0292). Patients, who received full and reduced DOAC doses, were comparable in the frequency of BARC 2-5 bleedings (0.78 vs 0.75, Log-Rank p=0.06742). Conclusions. The administration of a reduced DOACs dose as a part of TAT in patients with AF, who underwent PCI, was associated with significant increase in the incidence of all thrombotic events, compared to patients, who received full dose of anticoagulants. The number of hemorrhagic complications was comparable.

Aim: to compare two anticoagulant therapy (ACT) regimens in the treatment of venous thrombosis (VT) in patients after catheter interventions - electrophysiological studies (EFIs) and ablations: enoxaparin followed by warfarin, and rivaroxaban monotherapy. Materials and methods. The study included patients from 18 years and older with heart rhythm disorders and planned catheter ablation. When parietal venous thrombosis (VT) were detected at the femoral vein puncture site, all patients were randomly assigned to two treatment groups. In group I enoxaparin 1 mg/kg was prescribed every 12 hours with switching to warfarin after 7 days with maintenance of the target INR values (2.0-3.0). In group II rivaroxaban therapy was started at a dose of 15 mg twise/day for 21 days with a further transition to a dose of 20 mg/day. The total period of observation and treatment of patients was at least 3 months. Results. 408 patients were observed, 42 (10.3%) patients with parietal VT were divided into two treatment groups. In group I (n=16) complete lysis of VT was noted by the 7th day of treatment in 7 (58.3%) patients, however this scheme was associated with a greater risk of complications (р=0.003) at the puncture site in the form of arteriovenous fistulae (n=1; 8.3%) and intermuscular hematomas (n=4; 25%). In group II (n=26), no complications were noted, the lysis time of VT was on average 21 days (n=18; 69.2%). Complete lysis of VT was noted in both groups at the time of the control observation point (3rd month). Conclusion. The efficiency of the two VT treatment regimens was comparable. Enoxaparin therapy is associated with a high risk of local complications, namely intermuscular hematomas (n=4; 25%) and arteriovenous fistulas (n=1; 8.3%). Rivaroxaban monotherapy is safer (p=0.003); in Group II none of the patients had any complications.

Aim. To investigate the prognostic value of renal function and to estimate glomerular filtration rate (GFR) changes during a 5-year follow-up of patients receiving warfarin therapy. Subjects and methods. 200 patients (124 men, 76 women) mainly from a group at high risk for thromboembolic events (mean CHA2DS2-VASc scores, 3.25±1.89) were examined. The patients’ mean age was 62.3±9.4 years; the follow-up period was 5 years. 74% of the patients received warfarin monotherapy (international normalized ratio (INR) 2.0 to 3.0); 36% took vitamin K antagonists in combination with one or two antiplatelet agents. The CKD-EPI formula was used to estimate GFR in all the patients at baseline and throughout the investigation once a year. Results. GFR less than 70.9 ml/min/1.73 m2 was found to be a predictor of fatal and nonfatal thrombotic events. The decreased GFR was unassociated with the development of major and clinically relevant hemorrhagic complications within 5 years of warfarin therapy. The initial decline in renal function (GFR