New anticoagulants for venous thromboembolism and atrial fibrillation: what the future holds

Factors Affecting the Formation and Treatment of Thrombosis by Natural and Synthetic Compounds

Venous thromboembolism (VTE) refers to deep vein thrombosis (DVT), whose consequence may be a pulmonary embolism (PE). Thrombosis is associated with significant morbidity and mortality and is the third most common cardiovascular disease after myocardial infarction and stroke. DVT is associated with the formation of a blood clot in a deep vein in the body. Thrombosis promotes slowed blood flow, hypoxia, cell activation, and the associated release of many active substances involved in blood clot formation. All thrombi which adhere to endothelium consist of fibrin, platelets, and trapped red and white blood cells. In this review, we summarise the impact of various factors affecting haemostatic disorders leading to blood clot formation. The paper discusses the causes of thrombosis, the mechanism of blood clot formation, and factors such as hypoxia, the involvement of endothelial cells (ECs), and the activation of platelets and neutrophils along with the effects of bacteria and reactive oxygen species (ROS). Mechanisms related to the action of anticoagulants affecting coagulation factors including antiplatelet drugs have also been discussed. However, many aspects related to the pathogenesis of thrombosis still need to be clarified. A review of the drugs used to treat and prevent thrombosis and natural anticoagulants that occur in the plant world and are traditionally used in Far Eastern medicine has also been carried out.

Pharmacokinetic-Pharmacodynamic Analysis' Role in Design of Phase ⅠClinical Trials of Anticoagulant Agents: A Systematic Review

INTRODUCTION

There remains an unmet need for better anticoagulants. The phase I clinical trial is of great significance in the development of anticoagulants, and the design is special. This system review aims to provide insights for the design of future phase I clinical trials of anticoagulants.

AREAS COVERED

We searched the database PubMed and ClinicalTrail.gov website, to collate the phase I clinical trial of anticoagulants in healthy people. The study protocol, inclusion-exclusion criteria, safety, and pharmacodynamic indexes were reviewed.

EXPERT OPINION

New anticoagulants under development focused on inhibiting one or more than one serine proteases within the coagulation cascade. Agents targeting intrinsic factors are in the pipeline of the drug development. The enrollment eligibility criteria have more restrictions on laboratory tests, medical history, or medication history related to bleeding and coagulation; more precautions were taken to assess and minimize the risk of hemorrhagic events. Pharmacodynamics markers were evaluated as a surrogate marker of anticoagulation potency to guide further dose selection in drug's development. In future, the positive control study can be applied in phase I studies of new anticoagulants with appropriate pharmacodynamics markers, which can provide more favorable information on making 'go/no' decision in drug development.

Triple therapy in patients with atrial fibrillation and acute coronary syndrome or percutaneous coronary intervention/stenting

Patients with atrial fibrillation (AF) and acute coronary syndrome (ACS) are at high risk of stroke, recurrent coronary ischemic events, and cardiovascular mortality. The composition of antithrombotic therapy including an oral anticoagulant and antiplatelet drug(s) should be tailored according to the individual patient's risk profile, to reduce the bleeding risk and maintain antithrombotic effect. There is no single antithrombotic treatment regimen that would fit to all patients with AF and ACS. However, available data promote the use of full-dose direct oral anticoagulants (DOACs) (dabigatran 150 mg twice daily or apixaban 5 mg twice daily) or rivaroxaban 15 mg once daily in patients with AF and ACS or percutaneous coronary intervention (PCI). For many patients, a DOAC plus P2Y12 inhibitor early after ACS and/or PCI would be optimal, whereas a longer course of triple therapy should be used in patients at high thrombotic risk.

Straight to the heart: Pleiotropic antiarrhythmic actions of oral anticoagulants

Mechanistic understanding of atrial fibrillation (AF) pathophysiology and the complex bidirectional relationship with thromboembolic risk remains limited. Oral anticoagulation is a mainstay of AF management. An emerging concept is that anticoagulants may themselves have potential pleiotropic disease-modifying effects. We here review the available evidence for hemostasis-independent actions of the oral anticoagulants on electrical and structural remodeling, and the inflammatory component of the vulnerable substrate.