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Clinical Neuroscience

MARCH 30, 2016

[The importance of anticoagulant therapy in patients with artial fibrillation in stroke prevention – summary of international data and novel therapeutic modalities]

MIROLOVICS Ágnes, PAPP Csaba, ZSUGA Judit, BERECZKI Dániel

[The most common cardiogenic cause of ischaemic stroke is atrial fibrillation which increases the probability of stroke five-fold and doubles case fatality. Based on international data the incidence of atrial fibrillation is approx. 2% however this rapidly increases with age. The necessity of using oral anticoagulants in the prevention of non-valvular atrial fibrillation related stroke is decided based on estimated stroke risk. The CHADS2 and the more predictive CHA2DS2-VASc scales are used for this purpose while the bleeding risk of patients treated with anticoagulant may be estimated by the HAS-BLED scoring scale. For decades oral anticoagulation meant using vitamin-K antagonists. Based on international data we can see that rate of anticoagulation is unacceptably low, furthermore most of the anticoagulated patients aren’t within the therapeutic range of INR (INR: 2-3). A lot of disadvantages of vitamin-K antagonists are known (e.g. food-drug interaction, need for regular coagulation monitoring, increased risk of bleeding), therefore compounds with new therapeutic target have been developed. The novel oral anticoagulants (NOAC) can be divided in two major subgroups: direct thrombin inhibitors (dabigatran etexilate) and Xa-factor inhibitors (rivaroxaban, apixaban, edoxaban). These products are administered in fix doses, they less frequently interact with other medications or food, and regular coagulation monitoring is not needed when using these drugs. Moreover several studies have shown that they are at least as effective in the prevention of ischaemic stroke than the vitamin-K antagonists, with no more haemorrhagic complications.]

Clinical Neuroscience

MAY 30, 2013

[Effective, safe stroke prevention with novel oral anticoagulants in patients with atrial fibrillation. Focus on dabigatran]

SZAPÁRY László, FEHÉR Gergely, BOSNYÁK Edit, DELI Gabriella, CSÉCSEI Péter

[Non-valvular AF is the most common cardiac arrhytmia. Its incidence increases with age. AF is an independent risk factor for ischaemic stroke, representing a five times higher risk for it, associated with a high mortality rate. Beside AF, there are several other risk factors which influence the risk of stroke. Stroke risk calculator can be used to assess the risk of patient having a stroke. The most endangered group of patients with AF are those who have already suffered from cerebrovascular event. The only effective medication for prevention of stroke due to AF had been the application of vitamin K antagonists (VKA) which considerably decrease the rate of ischaemic event in a patient with AF providing that the INR is in the therapeutic range. VKA have several limitations of use in clinical practice and the fear of bleeding complications results an underusing of these drugs. Only 50% of all patients treated with VKA reaches the therapeutic range of INR. The breakthrough of prevention of stroke in recent years is undisputedly the coming out of novel oral anticoagulants (NOACs, thrombin and Xa-factor inhibitors). Recent studies suggest that these novel drugs prove the same efficacy as VKA drugs, furthermore dabigatran in a dose of 2×150 mg or apixaban in 2×5mg was statistically superior to warfarin in the prevention of stroke. NOACs have shown a large reduction in intracranial hemorrhage compared with warfarin. They are given as a fixed dose and do not require persistent monitoring making them much more convenient. NOACs at guidelines of European Society of Cardiology act as a preferable drugs in case of ischaemic stroke with AF. Probably the extended use of NOACs in clinical practice will be the mainstream of stroke prevention in the future.]

Lege Artis Medicinae

APRIL 20, 2013

[Apixaban: the newest oral anticoagulant in Hungary for the treatment of patients with atrial fibrillation]

BORBÉLY Attila, ÉDES István

[In the past few years a number of articles have been published on the new oral anticoagulants (Xa-factor inhibitors, thrombin inhibitors). These new agents are increasingly used in the daily clinical practice in Hungary. The new oral anticoagulants have been shown to be at least as effective in the prevention of stroke and systemic embolization related to non-valvular atrial fibrillation as K vitamin antagonists. Moreover, their use is safe, can be administered in a daily fixed dose and, even in case of long-term use, they do not require regular laboratory testing. This review aims to summarise the most important theoretical and practical information on the newest direct Xa-factor inhibitor agent apixaban from the perspective of a cardiologist.]

Lege Artis Medicinae

SEPTEMBER 20, 2010

[New era of anticoagulation]

LOSONCZY Hajna

[Two types of anticogulants have been introduced into the clinical practice and used succesfully for more than 60 years: the heparins and the cumarins. Blood coagulation is targeted by the two drugs on many sites, their inhibitory action is not specific. The hirudins as specific trombin inhibitors have been introduced later for specific indications. After the discovery of the exact structure of the clotting factors, the drug development could have been directed against its active center which made possible the development of more specific anticoagulants. Some attributes of an ideal anticoagulants: sufficient efficacy with safe administration, predictable therapeutic effect with fixed dosing, no need for monitoring, oral administration, to have a specific antidote, no food or drug interactions. New anticoagulants are inhibitors of the initiation of blood coagulation. Tissue factor pathway inhibitors; inhibitors of the propagation of clotting process: activated protein C; indirect factor Xa inhibitors (requiering antithrombin to its actions: pentasaccharide, idrabiotaparinux and ultra-low-molecular weight heparins); direct FXa inhibitors, acting without antithrombin: rivaroxaban and apixaban; and out of the direct oral thrombin inhibitors acting against fibrin-formation, dabigatran-etexilate are discussed.]