|
Points total on the CHA2DS2VASc scale | ||
|
One "large" risk factor or ≥ 2 "clinically significant small risk factors" |
Oral anticoagulants |
|
|
One 'clinically significant small risk factor' |
Oral anticoagulants or acetylsalicylic acid at a dose of 75 - 325 mg / day. Oral coagulants have an advantage over acetylsalicylic acid. |
|
|
No risk factors |
Acetylsalicylic acid or do not use antithrombotic agents. It is preferable not to use antithrombotic agents. |
Antiplatelet drugs, including acetylsalicylic acid, are also widely applicable, and if there are indications for the use of acetylsalicylic acid, it is advisable to use it at a dose of 75 - 325 mg / day. It has been proven that in lower doses the antithrombotic effect is not achieved, and in large doses the risk of bleeding increases.
The risk of hemorrhagic complications should also be assessed (Table 4).
Index value HAS- BLED≥ 3 indicates a high risk of bleeding. In this case, the dose of the antithrombotic drug should be carefully selected, and the risk of bleeding during treatment with vitamin K antagonists and acetylsalicylic acid is comparable.
Table 4
Has-bled bleeding risk scale
|
Clinical characteristics |
Number of points (minimum 9) |
|
|
Arterial hypertension (systolic blood pressure> 160 mm Hg) | ||
|
Impaired renal function (dialysis, transplant, or serum creatinine> 200 μmol / L); liver (for example, cirrhosis or more than a twofold increase in bilirubin, combined with a threefold increase in AST, ALT, or ALP. | ||
|
Bleeding (history, or predisposition, hemorrhagic diathesis, anemia, etc.) | ||
|
Labile INR (unstable, high, or recently achieved target INR) | ||
|
Age over 65 | ||
|
Taking certain medications or alcohol (1 point each) (antiplatelet, NSAIDs, alcohol abuse) |
Prevention of thromboembolic complications in cardioversion
The increased risk of thromboembolism after cardioversion is well known. In this regard, anticoagulation is considered mandatory before elective cardioversion if AF persists for more than 48 hours or its duration is unknown (Fig. 3).
Treatment with vitamin K antagonists (INR 2.0-3.0) should be continued for at least 3 weeks prior to cardioversion. Thromboprophylaxis is recommended before electrical or drug cardioversion in patients with AF duration> 48 h. Vitamin K antagonist therapy should be continued for at least 4 weeks after cardioversion, given the risk of thromboembolism associated with left atrial and appendage dysfunction (called atrial silencing ≫). In the presence of risk factors for stroke or recurrence of AF, treatment with vitamin K antagonists is carried out for life, even if the sinus rhythm is maintained after cardioversion.
If the episode of AF lasts less than 48 hours, cardioversion can be performed urgently under the cover of intravenous administration of unfractionated heparin (followed by infusion or subcutaneous administration of low molecular weight).
In patients with risk factors for stroke, oral anticoagulant therapy is initiated after cardioversion and continued for life. unfractionated or low molecular weight heparin is used until the target INR (2.0-3.0) is reached. Oral anticoagulants should not be given in the absence of risk factors for thromboembolism.
Patients with AF> 48 h and hemodynamic impairment (angina pectoris, myocardial infarction, shock, or pulmonary edema) should undergo emergency cardioversion. Before the rhythm is restored, unfractionated (UFH) or low molecular weight (LMWH) heparin is prescribed. After cardioversion, oral anticoagulants are prescribed, and heparin treatment is continued until the target INR (2.0-3.0) is reached. The duration of anticoagulant therapy (4 weeks or for life) depends on the presence of risk factors for stroke.
Mandatory 3-week anticoagulation before cardioversion may be reduced if transesophageal echocardiography does not detect a left atrial thrombus or left atrial appendage. Using this method, it is possible to detect not only a thrombus in the auricle of the left atrium or in other parts of this chamber of the heart, but also spontaneous echoes or
plaque in the aorta. Cardioversion under the control of transesophageal echocardiography can serve as an alternative to 3-week anticoagulation before rhythm restoration, when experienced personnel and technical capabilities are available, and also when early cardioversion is required, anticoagulation is not possible (patient refusal or high risk of bleeding) or there is a high likelihood of a blood clot in the left atrium or its ear. If a thrombus in the left atrium is not detected by transesophageal echocardiography, then UFH or LMWH are prescribed before cardioversion, the administration of which is continued until the target INR is reached while taking oral anticoagulants.
In the presence of a thrombus in the left atrium or left atrial appendage, treatment with a vitamin K antagonist (INR 2.0-3.0) should be performed and transesophageal echocardiography should be repeated. When the thrombus dissolves, cardioversion can be performed, after which life-long therapy with oral anticoagulants is prescribed. If thrombus persists, rhythm restoration may be abandoned in favor of ventricular rate control, especially if symptoms of AF are controlled given the high risk of thromboembolism with cardioversion.
With an INR of more than 3.5, the risk of bleeding, including intracranial, increases significantly, and with an INR of 2.0-3.0, the risk of bleeding is not higher than with less than 2.0, but there is a therapeutic effect.
To assess the risk of bleeding, bleeding risk scales have been developed for patients receiving anticoagulant therapy. The most famous and effective in practice is the HAS-BLED scale (IIa A). A value of 3 or more is a high risk of bleeding and alertness is required - IIa B, but this does not exclude the use of oral anticoagulants.
HAS-BLED Bleeding Risk Assessment Scale:
When taking oral anticoagulants, vitamin K antagonists, the INR is the reference point for the clinical effect. For the prevention of thromboembolic complications in AF without heart valve lesions, the therapeutic INR range is 2.0-3.0 (the optimal range between efficacy and safety; ideally 2.2-2.3). Maintaining the INR within 1.5-2.5 in elderly patients has not justified itself (the number of strokes has increased), therefore, maintaining the INR less than 2.0 is not recommended. With an INR> 3.5, the risk of bleeding increases significantly, primarily of intracranial bleeding.
Sensitivity to warfarin is determined by the carriage of the cytochrome P450 2C9 (CYP2C9) gene, which controls the metabolism of warfarin in the liver, and the gene for the vitamin K epoxy reductase complex (VKORC1). They determine the required dose of warfarin and the risk of bleeding. Genotyping of these genes is justified only in patients with a high risk of bleeding. In 2010, the FDA published the values of the maintenance doses of warfarin depending on the polymorphisms of the above genes.
Separate groups of patients:
- planned surgical interventions: with a low risk of thromboembolic complications and the absence of mechanoprostheses of heart valves, it is possible to temporarily cancel vitamin K antagonists with the creation of subtherapeutic anticoagulation (INR<1,5) на срок до 48 часов без перехода на гепарин – IIa C. При приеме варфарина обычно отменяют за 5 дней до операции. В случае же высокого риска тромбэмболических осложнений или наличия механопротезов клапанов сердца временная отмена пероральных антикоагулянтов рекомендована с переходом на терапевтические дозы гепарина или НМГ («терапия моста») – IIa C. После вмешательства возобновление приема антагониста витамина К (в прежней дозе) возможно вечером дня операции при условии полного и успешного гемостаза – IIa B. При этом в случае «терапии моста» на этапе возобновления приема антагониста витамина К время перекреста с гепарином или НМГ должно быть не менее 5 суток. Если операция проводится экстренно, то можно, при необходимости дать небольшие дозы витамина К.
- ONMK or TIA: before starting antithrombotic therapy, it is necessary to make sure that the blood pressure values are controlled and hemorrhage in the brain is excluded using CT or MRI - IIa C. bleeding should not be prescribed anticoagulants - IIa C. With a large size of the focus of ischemic stroke, it is advisable to postpone the appointment of anticoagulants in view of the risk of hemorrhagic transformation of the focus - IIa C. If a patient with AF develops TIA, but stroke is excluded and there is no risk of bleeding, then it is recommended as it is possible to initiate the intake of anticoagulants earlier - IIa C. In case of hemorrhagic stroke, anticoagulants are canceled immediately and prescribed again after a long period of time and in the absence of a high risk of repeated hemorrhagic stroke.
- Chronic ischemic heart disease: With a stable course of ischemic heart disease (there is no acute ischemia and PTCA is not planned), monotherapy with oral anticoagulants, primarily warfarin (it is, at least, as effective as aspirin in the secondary prevention of ischemic heart disease, but there is less risk of bleeding than with the combined administration of acetylsalicylic acid and clopidogrel; studies ASPECT-2, WARIS-2) - IIb C. After surgical revascularization of the myocardium in a patient with AF, the question of combining vitamin K antagonists with one of the antiplatelet agents may be considered, but this is poorly understood - IIb C.
- PCI: It is necessary to avoid, if possible, implantation of drug-eluting stents, since in this case it will be necessary to take triple antithrombotic therapy for at least 1 year, and try to place bare metal stents. In this case, triple antiplatelet therapy is required for 1 month, then a vitamin K antagonist + clopidogrel for a year - IIa C. In the case of implantation of drug-eluting stents, triple antiplatelet therapy is required for 3-6 months, then a vitamin K antagonist + clopidogrel up to years after stenting - IIa C. If the patient is planned to have PTCA and a high or medium risk of thromboembolism, then the INR values should be kept within 2.0-3.0, but, if possible, radial access - IIa C. For primary emergency PTCA and INR more than 2.0 it is better to refrain from taking IIb / IIIa receptor blockers. Triple or dual antithrombotic therapy should be carried out in combination with proton pump inhibitors or H2-histamine receptors and maintain the INR within 2.0-2.5 - IIb C.
- OKS: for ACS and PCI, triple antiplatelet therapy is required for at least 6 months, then a vitamin K antagonist + clopidogrel or acetylsalicylic acid up to a year after stenting - IIa C. For ACS without PCI, either a combination of a vitamin K antagonist (INR 2, 0-3.0) with acetylsalicylic acid or monotherapy with a vitamin K antagonist with an INR of 2.5-3.5 - IIa C. Approaches to the treatment of ACS against the background of initial therapy with new oral anticoagulants have not been studied, therefore, a switch to warfarin is recommended. ECV with unstable hemodynamics, inability to control heart rate or persistent ischemia; preferably intravenous administration of beta-blockers (I C) or nondihydropyridine AAs (IIa C; in the absence of clinical signs of HF); in the presence of severe CHF, digoxin (IIb C) and / or amiodarone (I C) can be used.
- elderly: with age, in terms of preventing thromboembolic complications, the effectiveness of antiplatelet agents decreases, but the effectiveness of oral anticoagulants remains; but in the elderly, the risk of stroke and other thromboembolisms gradually increases, despite the continued use of anticoagulants.
- valve defects: with a combination of atrioventricular valve defects, only oral anticoagulants; in the presence of mitral valve defect, its correction should be considered separately. The target INR values for the mitral valve mechanoprosthesis are at least 2.5, for the aortic valve - 2.0 (I B).
- pregnancy: EKV is possible in all trimesters (the same power charges) - I C; in the first trimester, try to avoid any drugs; Beta blockers are best avoided (fetal growth retardation); in terms of anticoagulant therapy: only with a high risk of TE, in the first trimester only heparin or LMWH, AVK only from the 2nd trimester (I C) and canceled one month before delivery (I B); to reduce heart rate, beta-blockers and AK (very carefully in the first trimester) - IIa C; in terms of restoring the rhythm, you can use flecainamide or ibutilide - IIb C; with contraindications to beta-blockers and AK, digoxin - IIb C.
- postoperative AF: AF develops in 30% after CABG, 40% after valve surgery, and 50% after combined cardiac surgery; effective prophylaxis - beta-blockers and amiodarone also, but less effectively, reduce the risk of sotalol and atrial pacing; ACE inhibitors and ARBs, as well as GCS, statins are controversial, sometimes even harmful.
- CHF: to control PFS, first of all, beta-blockers - I A. With their insufficient effectiveness, digoxin - I B. Nondihydropyridine AAs only with intact EF and with ineffectiveness of beta-blockers - IIb C. With unstable hemodynamics and low EF, it is recommended to start treatment with amiodarone - IB; in the absence of DPP, the alternative in such cases is digoxin - I C. If there are indications for CRT, resolve the issue of ablation of the AV node - IIa B. In severe CHF and unstable hemodynamics, only amiodarone is used to control the rhythm - I C. It is possible to consider RFA - IIb B.
- DPP: in the presence of a combination of symptomatic DPP and AF, RFA is indicated - I A; in socially responsible professions, even with non-symptomatic DPP and AF - I B. In asymptomatic, but clearly manifest forms of DPP and AF, RFA can also be considered (recommended for additional examination of CPP) - I B. In the absence of obvious indications against the background of a combination of DPP and AF, RFA may be conducted after an explanatory conversation about possible risks at the request of the patient - IIa B.
Demonstrates better results than standard bleeding risk scales, which are based only on clinical risk factors. The benefits of oral anticoagulant therapy (OAC) in AF are known to be based on a balance between reducing the risk of ischemic stroke and increasing the risk of major bleeding. At the moment, the scale is most often used to assess the risk of bleeding against the background of CBC. HAS-BLED which takes into account clinical risk factors. However, in recent years, information has been obtained that some biomarkers are capable of providing additional information about the risk of bleeding in patients with AF, so it would be reasonable to assume that our ability to predict these complications will improve if these variables are included in the model. The new scale for assessing the risk of bleeding is called ABC (from the English words for "age", "biomarkers" and clinical history). It was able to demonstrate higher sensitivity and feasibility rates than the popular clinical scales HAS-BLED and ORBIT, so it has good prospects as a tool for justifying clinical decisions in the field of anticoagulation in patients with AF. Research on this new scale was published in the June 4, 2016 issue of the Lancet.
This study was carried out by a team of scientists from Uppsala University in Sweden with financial support from Bristol-Myers Squibb, Pfizer, Boehringer Ingelheim and Roche Diagnostics. Scientists included in the new model those of the available biomarkers that seemed to them to have the highest predictive value in assessing the risk of bleeding in AF. These included growth differentiating factor-15 (GDF-15), which is a marker of oxidative stress; troponin T, determined by highly sensitive methods of analysis (hs-TnT), which is a marker of myocardial damage; used to assess renal function cystatin C or the estimated glomerular filtration rate (eGFR), as well as markers of anemia (hemoglobin or hematocrit). The model also included clinical risk factors and the level of the N-terminal fragment of the brain natriuretic peptide type B (NT-proBNP) precursor, which was used as a biomarker of stroke risk.
Initially, the new risk scale was validated in a large cohort of patients who participated in the ARISTOLE study (Apixaban for Reduction in Stroke and other Thromboembolic Events in Atrial Fibrillation), in which patients received either apixaban (Eliquis, manufacturer Bristol-Myers Squibb / Pfizer) or warfarin. Biomarker data were available for a total of 14,537 ARISTOLE participants. Major bleeding occurred in 662 people.
Additional Information: Even short-term administration of NSAIDs to patients with atrial fibrillation on anticoagulants increases the risk of bleeding
Using the new ABC Bleeding Risk Scale, the researchers found that the strongest predictors of major bleeding in ARISTOLE participants were GDF-15, hemoglobin, hs-TnT, age, and a history of previous bleeding. These five variables were included in a new, revised version of the ABC model, whose ability to predict the risk of major bleeding was compared with that of the HAS-BLED scale and the newer ORBIT scale. The so-called c-index was 0.68 for the ABC scale (its value 1.0 corresponds to the ideal resolution of the model, and the value 0.5 is considered bad and roughly corresponds to the predictive value of a coin toss). The HAS-BLED scale had a c-index of 0.61, while the ORBIT scale had a c-index of 0.65. The differences between both these scales and the ABC scale were significant: P<0,001 для шкалы HAS-BLED и P=0,0008 для шкалы ORBIT. Шкала ABC демонстрировала равные результаты у пациентов, которые получали в рамках исследования апиксабан или варфарин, и никаких значимых взаимодействий с эффектами тестировавшихся препаратов обнаружить не удалось.
The researchers then moved on to external validation of their results using biomarker data from the RE-LY study (Randomized Evaluation of Long-term Anticoagulation Therapy), in which AF patients received either dabigatran (Pradaxa, manufacturer Boehringer Ingelheim) or warfarin. Archived blood samples for biomarker research were available for 8468 patients, with 463 major bleeding events reported during the study. In the population of the RE-LY study, the new ABC scale also showed a higher c-index than the two competing scales: for ABC, the c-index was 0.71, for the HAS-BLED scale - 0.62, for the ORBIT scale - 0.68 (differences were highly significant: P<0,0001 и P=0,0016, соответственно). Шкала ABC также превосходила шкалы HAS-BLED и ORBIT с точки зрения способности прогнозировать внутричерепные кровоизлияния: значения c-индекса для трех шкал составили 0,66, 0,58 и 0,60, соответственно). Внешняя валидизация является важным шагом при подтверждении ценности новых шкал, и, таким образом, шкала ABC успешно справилась с этим этапом, превзойдя конкурентные шкалы.
It should also be noted that the new scale also equally well assessed the risk of bleeding in various subgroups of patients with AF and even proved to be able to accurately predict the risk in patients with low scores on the HAS-BLED and ORBIT scales.
Answering the question about the availability of the new scale for real practical application, the authors of the work reported that highly sensitive methods for the determination of troponin are already available in many countries of the world, and in June 2016. Roche plans to market a kit to determine the new biomarker GDF-15. As for the complexity of calculations, the authors do not consider this a significant problem: doctors are already actively using nomograms, electronic calculators or mobile applications to determine such frequently used parameters as, for example, creatinine clearance or GRACE score, so given the practical value of the scale ABC, most likely, for her, too, such auxiliary tools will quickly appear.
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HAS-BLED scale
The HAS-BLED scale is a simple and reliable clinical tool for assessing the risk of major bleeding within 1 year. Major bleeding means: any intracranial hemorrhage, bleeding requiring hospitalization, or accompanied by a decrease in hemoglobin> 2 g / l, or requiring blood transfusion.
The scale was created on the basis of a real cohort of 3978 patients with atrial fibrillation.
The Bleeding Risk Assessment Scale was presented by R. Pister et al. In 2010 and was named by HAS-BLED as an acronym:
— Hypertension - hypertension (systolic blood pressure> 160 mmHg);
— Abnormal renal / liver function - impaired renal function- 1 point (chronic dialysis, or serum creatinine> 200 μmol / L, or a history of kidney transplantation) and / orliver dysfunction- 1 point (chronic liver disease or functional disorders: bilirubin> 2× upper limit of normal, or increased aspartate aminotransferase / alanine aminotransferase / alkaline phosphatase> 3× upper limit of the norm);
— Stroke - stroke;
— Bleeding history or predisposition - history of bleeding and / or predisposition to them (eg, hemorrhagic diathesis, anemia);
- Labile international normalized ratio (INR)- labile international normalized ratio< 60 % (the indicator of the blood coagulation system, calculated when determining the prothrombin time, the indicator was introduced for uniformity in assessing the effect of anticoagulants on the prothrombin time and the correction of the administration of doses of anticoagulants);
— Elderly - age (> 65 years old);
— Drugs / alcohol concomitantly - joint medication (for example, anticoagulants and nonsteroidal anti-inflammatory drugs)- 1 point and / or alcohol- 1 point.
1 point is awarded for each point, the result is a simple sum of points. The maximum number of points on the scale is 9.
The effectiveness of any antithrombotic treatment must be balanced against the risk of major bleeding, especially intracerebral bleeding, which is often fatal. Therefore, the risk of bleeding should be assessed prior to the administration of anticoagulants in patients with atrial fibrillation.
Patients at high risk of bleeding (HAS-BLED score> 3) should undergo regular clinical examination after starting oral anticoagulant therapy.
The HAS-BLED scale has been included in the European and Canadian guidelines for the treatment of atrial fibrillation since 2010. The scale has been validated on various independent cohorts and correlates well with the risk of intracerebral hemorrhage.
Bibliography
1. Pisters R., Lane D.A., Nieuwlaat R., de Vos C.B., Crijns H.J., Lip G.Y. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey // Chest. - 2010 Nov. - 138 (5). - 1093-100.
2. Authors / Task Force Members, Camm A.J., Lip G.Y., De Caterina R. et al. 2012 focused update of the ESC Guidelines for the management of atrial fibrillation: An update of the 2010 ESC Guidelines for the management of atrial fibrillation. Developed with the special contribution of the European Heart Rhythm Association // Eur. Heart J. - 2012 Nov. - 33 (21). - 2719-47.
3. Lip G.Y., Frison L., Halperin J.L., Lane D.A. Comparative validation of a novel risk score for predicting bleeding risk in anticoagulated patients with atrial fibrillation: the HAS-BLED (Hypertension, Abnormal Renal / Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs / Alcohol Concomitantly) score / / J. Am. Coll. Cardiol. - 2011 Jan 11. - 57 (2). - 173-80.
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