Eficácia e segurança de anticoagulantes orais diretos comparados à anticoagulação tradicional com heparina e varfarina para tratamento de tromboembolismo pulmonar e trombose venosa profunda / Effectiveness and safety of direct oral anticoagulants compared to traditional anticoagulation with heparin and varfarine to treat pulmonary thromboembolism and deep venous thrombosis

Tecnologia: Inibidores Diretos do Fator Xa (IDFXa) ­ Rivaroxabana, Apixabana, Edoxabana ­ e Inibidores Diretos da Trombina (IDT) ­ Dabigatrana ­ todos são anticoagulantes orais diretos (DOAC). Indicação: tratamento e prevenção de fenômenos tromboembólicos. Pergunta: Para tratamento de tromboembolismo pulmonar (TEP) e trombose venosa profunda (TVP), os DOAC são mais eficazes e seguros que a anticoagulação tradicional com heparina e varfarina? Métodos: Levantamento bibliográfico na base de dados Pubmed seguindo estratégias de buscas predefinidas. Avaliação da qualidade metodológica das revisões sistemáticas com a ferramenta Assessing the Methodological Quality of Systematic Reviews (AMSTAR). Resultados: Foram selecionadas e incluídas 4 revisões sistemáticas. Conclusão: Na maioria dos estudos incluídos, os DOAC demonstraram eficácia e segurança similar à anticoagulação tradicional com heparina e varfarina para tratamento de TEP e TVP. Em um estudo, o risco de TVP recorrente foi menor no tratamento de IDFXa (por menos 3 meses de tratamento) e de episódios de sangramento maior foi menor no tratamento de IDT e IDFXa (por mais 3 meses de tratamento)

Technology: Direct Factor Xa Inhibitors (DFXaI) - Rivaroxaban, Apixaban, Edoxaban ­ and Direct Thrombin Inhibitors (DTI) - Dabigatran - all are direct oral anticoagulants (DOAC). Indication: treatment and prevention of thromboembolic phenomena. Question: For treatment of pulmonary thromboembolism (PTE) and deep vein thrombosis (DVT), are DOACs more effective and safer than traditional anticoagulation with heparin and warfarin? Methods: Bibliographic survey in the Pubmed database following predefined search strategies. Evaluation of the methodological quality of systematic reviews with the tool Assessing the Methodological Quality of Systematic Reviews (AMSTAR). Results: 4 systematic reviews were selected and included. Conclusion: In most of the included studies, DOAC demonstrated similar efficacy and safety to traditional anticoagulation with heparina and warfarin for the treatment of PTE and DVT. In one study, the risk of recurrent DVT was lower in the treatment of DFXaI (for at least 3 months of treatment) and of major bleeding episodes was lower in the treatment of DTI and DFXaI (for another 3 months of treatment)

Nuevos anticoagulantes orales: actualización / New oral anticoagulants: a review

Resumen: Los anticoagulantes orales clásicos del tipo cumarinas han estado disponibles para uso clínico por más de medio siglo. Tienen gran eficacia para tratar o prevenir trombosis y tromboembolias, y son drogas cuyo uso ha aumentado con el mejor conocimiento clínico, el aumento de los factores de riesgo y el envejecimiento de la población. Entre sus desventajas se incluyen la alta variabilidad de su efecto en cada sujeto y entre individuos, la influencia del nivel de ingesta de vitamina K, la necesidad de control periódico del nivel de anticoagulación, su interacción con múltiples drogas. Si bien, el rango terapéutico está estandarizado, es estrecho, haciendo que el tiempo en rango terapéutico sea de ≈ 60%. Por estas limitaciones, se han creado nuevos anticoagulantes orales (NACOs), siendo progresivamente aprobados para uso clínico por agencias internacionales. Genéricamente, son de 2 tipos: inhibidores selectivos de trombina (dabigatrán) o de FXa (rivaroxabán, apixabán, edoxabán y betrixabán). Los NACOs se caracterizan por su dosificación una o dos veces al día, rapidez de acción, corta vida media en la circulación, predictibilidad de su efecto, dosis preestablecidas, sin necesidad de control periódico y con escasa o nula interacción con otras drogas. Estas ventajas no se han traducido en la mayoría de los ensayos en un superior efecto antitrombótico o menor riesgo de sangrado, y en su mayoría (salvo dabigatrán) carecen de antídoto específico demostrado.

Abstracts: Vitamin K inhibitors, coumarins, have been used for more than 50 years with no dispute by other drugs. Coumarins have demonstrated great efficacy in the treatment and prophylaxis of thrombotic and thromboembolic disorders, and their use has increased progressively with the advance of clinical knowledge as well as the increase of risk factors and aging of the population. Limitations of coumarins include great variability intra and inter-individuals, the influence of foods rich in vitamin K, the need for periodical assessment of the anticoagulant level and drug interactions. The therapeutic range is standardized using the INR (International Normalized Ratio). However, the therapeutic window is narrow, with frequent periods of either over or under-dosing, with the concomitant increase of bleeding and thrombotic risks, respectively. Long-term accredited anticoagulant clinics and clinical trials report that, at best, only ≈60% of time in treatment the patients are within the therapeutic range. These limitations have created the need for new oral anticoagulants (NOACs), and several of them have been approved for clinical use by international agencies after exhaustive and specific clinical trials. Generically, NACOs are belong in two types: selective inhibitors of thrombin (dabigatran) or FXa (rivaroxaban, apixaban, edoxaban and betrixaban). NOACs are prescribed once or twice daily, the onset of action is very fast, have a low T1/2 in the circulation, their effects are highly predictable, doses are pre-established, do not need laboratory control and have a low rate of interaction with other drugs. Despite these advantages most clinical trials have shown NOACs to be not inferior with respect to coumarin. However, NOACs have no clear advantages over warfarin in antithrombotic effect or bleeding reduction. Furthermore, most of them (except dabigatran) have no specific antidotes yet.

Características basales, manejo de terapias antitrombóticas y pronóstico de pacientes chilenos con FA no valvular. Lecciones del Registro GARFIELD AF en Chile / Features, management and prognosis of Chilean patients with non valvular atrial fibrillation: GARFIELD AF registry

Background: Atrial fibrillation (AF) is the most common cardiac arrhythmia and is associated with high rates of death, ischemic stroke and systemic embolism (SE). There is scarce information about clinical characteristics and use of anti-thrombotic therapies in Chilean patients with non-valvular AF. Aim: To describe the characteristics and 1-year outcomes of patients with recently diagnosed AF recruited in Chile into the prospective global GARFIELD-AF registry. Material and Methods: Between 2011-2016, we prospectively registered information of 971 patients recruited at 15 centers, 85% of them from the public system and 15% from the private sector. Demographics, clinical characteristics and use of antithrombotic therapies were recorded for all patients. Adverse clinical outcomes were analyzed in 711 patients with 1-year follow-up. Results: The mean age was 71.5 years (66-79), 50% were men. Mean CHAD2S2 Vasc and HAS BLED scores for stroke risk were 3.3 (2.0-4.0) and 1.5 (1.0-2.0) respectively. Oral anticoagulants were prescribed in 82% of patients. Seventy percent received Vitamin K antagonists, 10% novel direct anticoagulants or antiplatelet therapy and only 8% did not receive any antithrombotic therapy. Mean time in optimal therapeutic range (an international normalized ratio of 2 to 3), was achieved in only 40.7% (23.0-54.8) of patients receiving Vitamin K antagonists. One year rates of death, stroke/systemic embolism and bleeding were 4.75 (3.36-6.71), 2.40 (1.47-3.92) and 1.64% (0.91-2.97) per 100 person-years. Ischemic stroke occurred in 1.8% and hemorrhagic stroke in 0.8% of patients at 1-year of follow up. Conclusions: Although the use of vitamin K antagonists at baseline was high, the mean time in optimal therapeutic range was low. Mortality and stroke rates are higher than those reported in other contemporary registries.

Trombocitopenia inducida por heparina: Nuevas opciones terapéuticas / Heparin-induced thrombocytopenia. New therapeutical options

La trombocitopenia inducida por heparina (TIH) es una reacción adversa inmunológica mediada por la formación de anticuerpos contra el complejo heparina-factor plaquetario 4 (FP4), caracterizada por la presencia de trombocitopenia y la asociación paradojal de trombosis arterial o venosa. Es una complicación poco frecuente pero grave del uso de cualquier tipo de heparina. En tratados con procedimientos cardiovasculares como intervención coronaria percutánea y cirugía de revascularización cardiaca, la prevalencia de anticuerpos es significativamente mayor que en otros escenarios clínicos. El reconocimiento de las características clínicas y de laboratorio permite la suspensión inmediata de la heparina y la instauración de tratamiento anticoagulante alternativo, para evitar la progresión y formación de nuevos trombos y sus complicaciones. En la presente revisión se resumen las diferentes alternativas terapéuticas para la TIH, en particular los anticoagulantes orales directos (DOACS) como el dabigatran, rivaroxaban y apixaban que pueden proporcionar una nueva opción para el tratamiento de TIH.

Heparin-induced thrombocytopenia (HIT) is an immune-mediated adverse reaction due to antibodies to a multimolecular complex of heparin and platelet factor 4 (PF4) characterized by moderate thrombocytopenia and paradoxical arterial or venous thrombosis. It is a relatively infrequent complication related to the administration of any type of heparin. In patients undergoing percutaneous coronary revascularization or coronary artery by-pass graft the prevalence of HIT is higher than in other clinical settings. Recognizing clinical and laboratory features of HIT allow immediate discontinuation of heparin and the use of alternative anticoagulants to avoid serious thrombotic complications. In this review, we summarize different therapeutic options for the treatment of HIT with special emphasis on direct oral anticoagulants (DOACS) such as dabigatran, rivaroxaban and apixaban. DOACS might represent a therapeutic alternative for HIT treatment.

Hemodiálisis para remover el anticoagulante dabigatrán en situaciones de urgencia / Hemodialysis to remove anticoagulant dabigatran during emergencies

El dabigatrán es un nuevo inhibidor directo de la trombina, de administración oral, empleado para la prevención de eventos tromboembólicos en pacientes con fibrilación auricular no valvular. A diferencia de la warfarina, no se dispone de un antídoto conocido. La hemodiálisis ha sido sugerida como un método para remover el dabigatrán y reducir el efecto anticoagulante. Se presenta el caso de un paciente con antecedente de fibrilación auricular y medicado con dabigatrán, que fue admitido en el hospital para una cirugía abdominal de urgencia. A las seis horas de la última dosis recibida, los estudios de coagulación mostraban alteración. Ante la falta de antídoto para revertir los efectos, se decidió realizar hemodiálisis. Luego de tres horas de diálisis los parámetros de coagulación tendieron a normalizarse y el paciente fue operado sin presentar hemorragias anormales durante la cirugía o en el postoperatorio.

Dabigatran is an oral anticoagulant from the class of the direct thrombin inhibitors, indicated for prevention of thromboembolic events in patients with non valvular atrial fibrillation. Unlike warfarin, dabigatran has no known antidote. Hemodialysis has been suggested as a method for removing dabigatran and thereby reducing its anticoagulant effect. We report the case of a patient with a known history of atrial fibrillation, treated with dabigatran, who was admitted for emergency abdominal surgery. At six hours after the last dose received, coagulation studies were altered. In absence of an antidote to reverse its effects, it was decided to perform hemodialysis. After three hours of dialysis coagulation parameters were improved and the patient underwent surgery without showing abnormal bleeding during surgery or in the postoperative period.

Rebleeding after Initial Endoscopic Hemostasis in Peptic Ulcer Disease

Endoscopic hemostasis is the first-line treatment for upper gastrointestinal bleeding (UGIB). Although several factors are known to be risk factors for rebleeding, little is known about the use of antithrombotics. We tried to verify whether the use of antithrombotics affects rebleeding rate after a successful endoscopic hemostasis for peptic ulcer disease (PUD). UGIB patients who underwent successful endoscopic hemostasis were included. Rebleeding was diagnosed when the previously treated lesion bled again within 30 days of the initial episode. Of 522 UGIB patients with PUD, rebleeding occurred in 93 patients (17.8%). The rate of rebleeding was higher with aspirin medication (P=0.006) and after a long endoscopic hemostasis (P<0.001). Of all significant variables, procedure time longer than 13.5 min was related to the rate of rebleeding (OR, 2.899; 95% CI, 1.768-4.754; P<0.001) on the logistic regression analysis. The rate of rebleeding after endoscopic hemostasis for PUD is higher in the patients after a long endoscopic hemostasis. Endoscopic hemostasis longer than 13.5 min is related to rebleeding after a successful endoscopic hemostasis for PUD.

Tromboembolismo pulmonar: terapia pós-crise / Pulmonary embolism: therapy post-crisis

O principal objetivo do tratamento pós-fase aguda do tromboembolismo pulmonar é a prevenção de recorrência. Os pacientes devem ser estratificados quanto ao risco de recorrência da doença. Há mais de 50 anos os antagonistas da vitamina K são utilizados nessa fase do tratamento. Recentemente surgiram novos anticoagulantes orais que não necessitam de monitorização laboratorial, sendo uma promessa para o manejo mais fácil do tratamento.

The main objective of treatment post-acute phase of pulmonary thromboembolism is prevention of recurrence. Patients should be stratified by risk of disease recurrence. For over fifty years, vitamin K antagonists are used in this phase of treatment. Recently, a new anticoagulants which do not require laboratory monitoring with a promise for an easier handling of the treatment.

In vivo antithrombotic properties of a heparin from the oocyte test cells of the sea squirt Styela plicata(Chordata-Tunicata)

In the ascidian Styela plicata, the oocytes are surrounded by two types of accessory cells named follicle cells and test cells. A heparin-like substance with an anticoagulant activity equivalent to 10 percent of mammalian heparin and about 5 percent as potent as the mammalian counterpart for the inhibition of thrombin by antithrombin was isolated from the oocyte test cells. In the present study, we compared the antithrombotic and hemorrhagic effects of sea squirt oocyte test cell heparin with those of porcine heparin in rat models of venous thrombosis and blood loss. Intravenous administration of the oocyte test cell heparin to Wistar rats (both sexes, weighing ~300 g, N = 4 in each group) at a dose of 5.0 mg/kg body weight, which produced a 1.8-fold increase in plasma activated partial thromboplastin time, inhibited thrombosis by 45 ± 13.5 percent (mean ± SD) without any bleeding effect. The same dose of porcine heparin inhibited thrombosis by 100 ± 1.4 percent, but produced a blood loss three times greater than that of the saline-treated control. However, 10-fold reduction of the dose of porcine heparin to 0.5 mg/kg body weight, which produced a 5-fold increase in plasma-activated partial thromboplastin time, inhibited thrombosis by 70 ± 13 percent without any bleeding effect. The antithrombotic properties of a new heparin isolated from test cells of the sea squirt S. plicata, reported here for the first time, indicate that, although sea squirt oocyte test cell heparin was a poor anticoagulant compared to porcine heparin, it had a significant antithrombotic effect without causing bleeding.