Manejo de hemorragia asociada a anticoagulantes orales directos: estado actual de las estrategias de reversión / Management of bleeding associated with direct oral anticoagulants: update on reversal strategies

Direct oral anticoagulants (DOACs), including the direct thrombin inhibitor dabigatran and the direct factor Xa inhibitors rivaroxaban, apixaban and edoxaban have at least comparable efficacy as vitamin K antagonists along with a better safety profile, reflected by a lower incidence of intracranial hemorrhage. Specific reversal agents have been developed in recent years. Namely, idarucizumab, a specific antidote for dabigatran, is currently approved in most countries. Andexanet, which reverses factor Xa inhibitors, has been recently approved by the FDA, and ciraparantag, a universal antidote targeted to reverse all DOACs, is still under investigation. In this review we provide an update on the pharmacology of DOACs, the risk of hemorrhagic complications associated with their use, the measurement of their anticoagulant effect and the reversal strategies in case of DOAC-associated bleeding.

Comparison of Rhythm and Rate Control Strategies for Stroke Occurrence in a Prospective Cohort of Atrial Fibrillation Patients

PURPOSE: Comparisons of rhythm and rate control strategies for stroke prevention in patients with atrial fibrillation (AF) are still inconclusive. We compared differences in clinical outcomes between the rhythm and rate control strategies. MATERIALS AND METHODS: The COmparison study of Drugs for symptom control and complication prEvention of Atrial Fibrillation (CODE-AF) registry prospectively enrolled 6000 patients who were treated for AF using real-world guideline adherence at multiple referral centers. In total, 2508 (41.8%) patients were clinically followed up for over six months. Of these, 1134 (45.2 %) patients treated by rhythm control and 1374 (54.8 %) patients treated by rate control were analyzed for clinical outcomes, including stroke and cardiovascular outcomes. RESULTS: Among all patients (age, 68±10 years; male, 62.4%), those treated with the rhythm control strategy were significantly younger, had more symptomatic paroxysmal AF, and a shorter AF duration, and were less likely to have diabetes, renal dysfunction, and heart failure, compared to those treated with the rate control strategy (CHA₂DS₂-VASc score 2.4±1.5 vs. 3.1±1.7, p < 0.001). Even though oral anticoagulation was similarly prescribed in both groups, occurrence of stroke was less likely to occur in the rhythm control strategy group (0.0% vs. 0.7%, p=0.015). Multivariate Cox hazard regression showed that only age, especially more than 75 years old, were significantly correlated with the occurrence of stroke, regardless of the strategy used for treatment. CONCLUSION: In this prospective AF cohort, compared with the rate control strategy, the rhythm control strategy was associated with fewer cardiovascular events and strokes in a short-term period.

Use of direct oral anticoagulants for chronic thromboembolic pulmonary hypertension

OBJECTIVES: Chronic thromboembolic pulmonary hypertension is one of the most prevalent forms of pulmonary hypertension and is a major complication of acute pulmonary embolism. One mainstay of chronic thromboembolic pulmonary hypertension treatment is lifelong anticoagulation. The recent advent of direct oral anticoagulants for acute pulmonary embolism treatment has provided a viable and effective alternative for treating this condition. However, little is known about the efficacy of this new class of drugs for treating chronic thromboembolic pulmonary hypertension. We aimed to evaluate the safety and efficacy of direct oral anticoagulants in the treatment of chronic thromboembolic pulmonary hypertension. METHODS: A cohort of chronic thromboembolic pulmonary hypertension patients who initiated treatment with direct oral anticoagulants between June 2015 and November 2016 were enrolled in this study. RESULTS: Sixteen patients used rivaroxaban, three used dabigatran and one used apixaban for a mean follow-up of 20.9 months. The mean age was 51 years, and eighteen patients were classified as functional class II/III. Eight patients underwent a pulmonary endarterectomy and exhibited clinical, hemodynamic and functional improvement and currently continue to use direct oral anticoagulants. No episode of venous thromboembolism recurrence was identified during the follow-up period, but there was one episode of major bleeding after a traumatic fall. CONCLUSIONS: Although direct oral anticoagulants appear to be a safe and effective alternative for treating chronic thromboembolic pulmonary hypertension, larger studies are needed to support their routine use.

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.

New orally active anticoagulants in critical care and anesthesia practice: The good, the bad and the ugly.

With the adoption of dabigatran, rivaroxaban, and apixaban into clinical practice, a new era has arrived in the practice of oral anticoagulants. Venous thromboembolism (VTE) has traditionally been underdiagnosed and under treated in Asia. With increasing longevity, the diagnosis and the need for management of atrial fibrillation (AF) and VTE is likely to increase significantly. The new orally active anticoagulants (NOACs) have reasonably filled the lacunae that clinicians traditionally faced when treating patients with vitamin K antagonist (VKA). Unlike VKA, NOACs do not need frequent monitoring. Therefore, more patients are likely to get therapeutic effects of anticoagulation and thus reduce morbidity and mortality associated with VTE and AF. However, the clinicians need to be circumspect and exercise caution in use of these medications. In particular (in geriatric population), the clinicians should look out for drug-drug interactions and underlying renal insufficiency. This would ensure therapeutic efficacy and minimize bleeding complications. Here, it is important to note that the antidote for NOACs is not available and is a major concern if emergency surgical procedure is required in their presence.

Anti-Xa e antitrombínicos específicos nas síndromes isquêmicas miocárdicas instáveis com e sem supradesnível do segmento ST / Factor Xa inhibitors and selective antithrombin agents in acute coronary syndromes

As síndromes isquêmicas miocárdicas instáveis incluem um amplo espectro de manifestações da doença coronária, variando de angina instável e infarto do miocárdio sem supradesnível do segmento ST até infarto do miocárdio com dupradesnível do seguimento ST. O mecanismo fisiopatológico subjacente envolve a combinação de aterosclerose e um evento trombótico. O tratamento com heparina não fracionada ou de baixo peso molecular tem demonstrado ser eficaz e seguro nesses pacientes. Entretanto, uma limitação inerente a essas medicações é a ausência de efeito na trombina ligada ao coágulo. Novos anticoagulantes foram desenvolvidos, tendo como alvo as duas formas de trombina - livre e aquela aderida ao coágulo (inibidores diretos da trombina) - bem como outros componentes individuais da cascata de coagulação (inibidores diretos ou indiretos do fator Xa). Esses agentes anticoagulantes demonstraram resultados promissores em estudos pré-clínicos e foram avaliados em ensaios de síndromes isquêmicas agudas em grande escala. Esta revisão discute a eficácia e a segurança desses novos agentes quando comparados com os regimes que utilizam heparina como anticoagulantes de escolha.

Acute coronary syndromes include a broad spectrum of coronary artery disease ranging from unstable angina, non-ST-segment elevation myocardial infarction to ST-segment elevation myocardial infarction. The underlying pathophysiological mechanism involves a combination of atherosclerosis and a thrombotic event. Treatment with unfractionated heparin or low-molecular-weight heparin has shown to be effective and safe in these patients. However, a common limitation of these medications is the lack of effect on clot-bound thrombin. Novel anticoagulants targeted for both the free and clot-bound forms of thrombin (direct thrombin inhibitors), or other individual components of the coagulation cascade (direct or indirect factor Xa inhibitors). These anticoagulants have shown promising results in preclinical testing and have been evaluated in large-scale clinical acute coronary syndrome trials. This review discusses the efficacy and safety of these novel agents compared with heparin-based anticoagulants.