Changes in Prescribing Antithrombotic Therapy in Patients with Atrial Fibrillation in the Multidisciplinary Hospital in Volgograd from 2012 to 2020

Aim. To study the frequency of prescribing antithrombotic agents in patients with non-valvular atrial fibrillation (AF) in real clinical practice, to evaluate changes of prescriptions from 2012 till 2020.

Material and methods. The medical records of inpatients (Form 003/y) with the diagnosis AF, hospitalized in the cardiological department were analyzed. According to the inclusion criteria, the patients were over 18 years of age, established diagnosis of non-valvular AF. There were two exclusion criteria: congenital and acquired valvular heart disease and prosthetic heart valves. In retrospective analysis we have included 263 case histories in 2012, 502 ones in 2016 and 524 in 2020. CHA2DS2-VASc score was used for individual stroke risk assessment in AF. The rational use of the antithrombotic therapy was evaluated according with current clinical practice guidelines at analyzing moment.

Results. During period of observation the frequency of antiplatelet therapy significantly decreased from 25,5% to 5,5% (р<0.001), decreased the frequency of administration of warfarin from 71,9% to 18,3% (р<0.001). The frequency of use of direct oral anticoagulants increased in 2020 compared to 2016 (р<0.001). For patients with a high risk of stroke anticoagulant therapy was administered in 71.8% of cases in 2012, 88.5% in 2016 and 92.5% in 2020. Before discharge from hospital majority of patients (72%) achieved a desired minimum international normalized ratio (INR) from 2.0 to 3.0 in 2012. In 2016 and 2020 an only 33% and 40.6% of patients achieved INR (2.0-3.0).

Conclusion. Doctors have become more committed to following clinical guidelines during the period of the investigation. In 2020 antithrombotic therapy for atrial fibrillation was suitable according to current clinical guidelines.

Anticoagulation therapy in atrial fibrillation after intracranial hemorrhage

Intracerebral hemorrhage (ICH) is severe and fatal complication of anticoagulant therapy with an incidence 0.3-0.7% per year. For patients with atrial fibrillation (AF) anticoagulants are administered for decreasing risk of stroke and systemic embolism. In this case the occurrence of intracranial bleeding is hard task for doctor. From the one side it is necessary to reverse the action of the drug for preventing the growth of hematoma. At the same time the discontinuation of therapy increases the risk of systemic embolism for patients with AF significantly. Clinical guidelines and studies have been reviewed about ICH during anticoagulant therapy. Nowadays there is no quality evidence about reversal of anticoagulant effects after ICH and optimal time of resumption of anticoagulant therapy. Firstly, we do not have large randomized controlled trials on this issue. The majority of clinical guidelines were based on retrospective studies and opinions of experts. Soon several randomized controlled trials will be finished and new data will be presented.

[Comparative efficacy and safety of direct oral anticoagulants in patients with atrial fibrillation and chronic kidney disease]

Aim To compare efficacy and safety of direct oral anticoagulants (DOACs) for prevention of stroke in patients with nonvalvular atrial fibrillation and reduced creatinine clearance.Material and methods Systematic search for literature and indirect comparison of DOACs were performed.Results The indirect comparison included five randomized clinical trials. The DOACs were comparable by the efficacy of preventing stroke and systemic embolism. The safety profiles had differences. Apixaban significantly decreased the relative risk of major bleeding compared to rivaroxaban by 27 % (relative risk (RR) 0.73; 95 % confidence interval (CI): 0.55-0.98). The apixaban advantage was even greater in the group of patients with a creatinine clearance &lt;50 ml/min: RR was reduced by 48 % compared to rivaroxaban (RR=0.52; 95 % CI: 0.32-0.84), by 50 % compared to dabigatran 300 mg/day (RR=0.50; 95 % CI: 0.31-0.81), and by 48 % compared to dabigatran 220 mg/day (RR=0.52; 95 % CI: 0.32-0.85)Conclusion The indirect comparison of DOACs showed that their efficacy was comparable. With respect of safety, apixaban is the preferrable DOAC for patients with atrial fibrillation and creatinine clearance below 50 ml/min.

Safety of Using Direct Oral Anticoagulants in Patients with Atrial Fibrillation and Chronic Kidney Disease

The purpose of this review is to examine the possibilities and prospects for the use of direct oral anticoagulants for the prevention of thromboembolic complications in patients with atrial fibrillation and chronic kidney disease. Chronic kidney disease is an independent risk factor for cardiovascular complications. Atrial fibrillation is associated with a higher risk of developing chronic kidney disease and more rapid progression of existing renal pathology. The presence of chronic kidney disease in atrial fibrillation on the one hand leads to an increased risk of thromboembolism, and on the other to an increased risk of bleeding when using anticoagulants. The standard for the prevention of thromboembolic complications in atrial fibrillation, including those with concomitant renal pathology, was considered warfarin for many years. However, modern studies have shown that the use of warfarin may enhance vascular calcification in patients with chronic kidney disease, which in turn may lead to an increased risk of ischemic strokes.

Analyzing clinical recommendations, randomized studies, meta-analyzes and a systematic review on the use of anticoagulants in patients with atrial fibrillation and renal pathology, revealed the advantage of using direct oral anticoagulants over warfarin at stage 1-3 of chronic kidney disease. Data on the use of direct oral anticoagulants with a more pronounced renal dysfunction and in patients on dialysis is limited due to the lack of a sufficient number of large randomized studies. Due to the presence of renal clearance in all oral anticoagulants, their pharmacokinetics changes to some extent with a decrease in the glomerular filtration rate, which requires dose adjustment of drugs depending on creatinine clearance. Therefore, the use of anticoagulants for the prevention of thromboembolic complications during atrial fibrillation requires special attention in patients with chronic kidney disease.

Comparative Analysis of Antithrombotic Therapy in In-Patients with Atrial Fibrillation

Aim. To study the frequency of prescribing antithrombotic agents in patients with non-valvular atrial fibrillation (AF) who were hospitalized in the cardiology department of a multidisciplinary hospital.

Material and methods. A retrospective one-time study of medical records of 765 patients with non-valvular AF treated in the cardiology department of a multidisciplinary hospital in 2012 and 2016 was performed.

Results. All patients were stratified in three groups depending on the CHA2DS2-VASc score. The frequency of prescribing antithrombotic agents was evaluated in each group. A low risk of thromboembolic complications was found in 1% (n=3) of patients in 2012 and 0.6% (n=3) in 2016. All these patients received antithrombotic agents. CHA2DS2-VASc=1 was found in 6% (n=15) of patients with AF in 2012 and in 3.4% (n=17) in 2016. A significant number of patients in this group received anticoagulant therapy with vitamin K antagonists (warfarin) or with direct oral anticoagulants. A high risk of thromboembolic complications (CHA2DS2-VASc≥2) was found in 93% of patient (n=245) in 2012 and in 96% (n=482) in 2016. Anticoagulant therapy was prescribed in 70.2% (n=172) patients with high risk in 2012 and 80% (n=387) in 2016. However, some patients with high risk of thromboembolic complications did not have the necessary therapy.

Conclusion. Positive changes in the structure and frequency of prescribing anticoagulant drugs in patients with AF and a high risk of thromboembolic complications were found during the years studied. 

HYBRID DECIDING MODULES WITH VIRTUAL STREAMS FOR CLASSIFICATION AND PREDICTION OF FUNCTIONAL STATE OF COMPLEX SYSTEMS

The problem reviewed of building intelligent decision support systems for classification and prediction of the functional state of complex systems in the article. To predict the state of complex systems, hybrid decision modules with virtual flows are proposed, which reflect the hidden system connections between real and virtual data. The vector of informative features at the input of the hybrid decision module consists of two subsectors, the first of which corresponds to real flows, and the second - to virtual flows. Simulation modeling of classification processes using latent variables was performed, which allowed to evaluate the effect on the quality of classification of artificially introduced virtual flows. The structure of a neural network model with virtual recurrent-type streams is developed. The structure consists of N consecutively included neural network approximants. The outputs of the previous approximators are combined with the vector of in-formative attributes of the subsequent approximators, which allows forming virtual flows of different dimensions. A method is developed for the formation of non-linear models of virtual flows, characterized by the use of the GMDH-simulation method to obtain models of the influence of real flows on virtual flows, learned through nonlinear adalines. The method makes it possible to form a subvector of latent variables of unlimited dimension. Non-linear models of virtual flows are formed through a method based on the use of GMDH modeling. The method makes it possible to obtain neural network structures built on the basis of GMDH models and nonlinear adalines, which make it possible to form a subvector of latent variables of unlimited dimensionality.

[Idiopathic hypercalciuria. Diagnosis and treatment]

Most patients with idiopathic hypercalciuria and calcium nephrolithiasis have a family history of the disease. Idiopathic hypercalciuria is a metabolic abnormality with various causes and developmental pathways. The systematic review describes specific mutations associated with idiopathic hypercalciuria and nephrolithiasis. Detection of these mutations may provide a better understanding of the pathogenesis of this heterogeneous disease and personalize patient management depending on the detected polymorphisms. A promising treatment option for a mutation in the vitamin D receptor gene is thiazide diuretics in combination with bisphosphonates. Among bisphosphonates, the drug of choice which has been most strongly supported by research evidence is alendronate.

MONITORING OF ANTICOAGULANT THERAPY IN PATIENTS WITH DEEP VEIN THROMBOSIS

Aim. To evaluate the prevalence of accomplished goal in laboratory clotting parameters for the anticoagulant therapy in deep vein thrombosis (DVT).

Material and methods. The study is performed as one-stage, descriptive, analytic, pharmacoepidemiologic investigation. The material for the study were 200 case histories of DVT from Volgograd hospitals. The analyzed were: structure of anticoagulant prescription, coagulogrammes with APTT, prothrombin complex and INR.

Results. Direct acting anticoagulants were prescribed in 91% cases. High-molecular heparin was used in 84,5% prescriptions, low-molecular heparins — in 6,5%. Monitoring of APTT was done only in 36% patients. The target values of APTT (1,5–2,5 times higher than upper limit) was reached only in 6% cases. Of the indirect anticoagulants warfarin was used in 75,5%. Although laboratory control of warfarin was done in 97% cases, only in 28% of patients INR at discharge was in the range 2,0–3,0.

Conclusion. The data witnesses a variety of drawbacks in anticoagulant therapy of DVT patients. High dosages of HMW heparin and warfarin, not enough rigourous control and dosage titration led to the absence of the desired therapeutic diapasone of hypocoagulation. 

[The place of novel oral anticoagulants in prevention and treatment of venous thromboembolism]

The notion "venous thromboembolism" combines two processes: thrombosis of deep veins and pulmonary artery thromboembolism. The necessity in long-term adequate anticoagulant therapy as the basic treatment of patients with deep vain thrombosis does not give rise to doubts, it should be started prior to instrumental verification of the diagnosis. The past decade was marked by the appearance on the pharmaceutical market of a new oral anticoagulant: selective blocker of the Xa factor of blood coagulation system - rivaroxaban. According to the data of large-scale randomized clinical trials, the efficacy and safety of rivaroxaban are comparable to those of traditional conventional anticoagulant therapy (non-fractionated/low-molecular-weight heparin NFH/LMW + warfarin). Indisputable advantages of new agents are as follows: the lack of the necessity in laboratory monitoring, no interaction with foodstuff, minimal interaction with other drugs, minimal risk for the development of haemorrhage, and simplicity of dosing.

[A method for creating fuzzy neural-network models using the MATLAB package for biomedical applications]

Problems of MATLAB-based simulation of hybrid neural networks for data classification in biomedical applications are considered. The neural-network structure is used as a defuzzifier. Graphic interfaces for constructing fuzzy neural-network models are suggested. Methods for merging models constructed using different MATLAB packages and an algorithm for constructing a fuzzy neural-network model are suggested. The algorithm includes both modules for tuning membership functions of the fuzzy system fuzzifier, and modules for tuning the parameters of the defuzzifier implemented as a two-layer neural-network structure of the perceptron type.