Antithrombotics and new interventions for venous thromboembolism: Exploring possibilities beyond factor IIa and factor Xa inhibition

Anticoagulants for atrial fibrillation: from warfarin and DOACs to the promise of factor XI inhibitors

Anticoagulation is the mainstay of stroke prevention in appropriate patients with atrial fibrillation. Due to advances in pharmacotherapy the anticoagulants used for this purpose have evolved significantly over the past decades with the aim of optimizing effectiveness while minimizing bleeding risks. Though significant improvements have been made toward this goal, bleeding risk remains the major concern with these therapies. An investigational class of agents which inhibit Factor XI have shown promise in pre-clinical and early clinical trials to significantly minimize bleeding while maintaining efficacy against stroke and systemic embolism. This mini-review will discuss anticoagulants currently used for stroke prevention in patients with atrial fibrillation including warfarin and direct oral anticoagulants. We will also review the mechanism of action and data from early clinical trials for Factor XI inhibitors and discuss their potential advantages and shortcomings.

Anticoagulation in chronic kidney disease: current status and future perspectives

Chronic kidney disease (CKD) is being diagnosed increasingly worldwide. It is often identified in individuals with comorbidities, which may increase the already heightened risk of thrombosis and hemorrhage associated with CKD. Oral anticoagulation is an effective means of reducing rates of ischemic stroke and systemic embolism in patients with atrial fibrillation and minimizes the morbidity and mortality caused by venous thromboembolic disease. Despite the proven benefits in the majority of patients, these have not been so clearly realized in patients with CKD due to the precarious balance between bleeding and thromboembolic complications. In this review, the current status of anticoagulant utilization in CKD is examined, and some practical recommendations are put forward to assist in the decision-making process of safely anticoagulating patients with CKD diagnosed with atrial fibrillation and venous thromboembolism.

Substituent effects of sulfonamide derivatives of metformin that can dually improve cellular glucose utilization and anti-coagulation

Metformin, the most frequently prescribed medicine for the management of type 2 diabetes, has been shown to reduce cardiovascular events in diabetic patients in pre-clinical and clinical studies. The present work reports the design, synthesis, and biological assessment of the impact of six benzenesulfonamide biguanides on various aspects of hemostasis, cell function, red blood cell integrity (RBC), and their ability to uptake glucose in human umbilical endothelial cells (HUVECs). It was found that all synthesized o- and m-benzenesulfonamides, particularly derivatives with nitro (3) and amino groups (4), are characterized by a good safety profile in HUVECs, which was further confirmed in the cellular integrity studies. The biguanide analogues with methoxy group (1, 2) and an amino substituent (5, 6) significantly increased glucose utilization in HUVECs, similarly to the parent drug. Intriguingly, compounds 1, 3, and 6 favourably influenced some of the coagulation parameters. Furthermore, derivative 3 also slowed the process of fibrin polymerization, indicating more beneficial anti-coagulant properties than metformin. None of the novel metformin analogues interact strongly with the erythrocyte lipid-protein bilayer. Our findings indicate that derivative 3 has highly desirable anti-coagulant properties, and compounds 1 and 6 have potential dual-action activity, including anti-hyperglycaemic properties and anti-coagulant activity. As such, these derivatives can be used as lead molecules for further development of anti-diabetic agents with a beneficial effect on hypercoagulability.

Factor XI inhibitors: cardiovascular perspectives

Anticoagulants are the cornerstone for prevention and treatment of thrombosis but are not completely effective, and concerns about the risk of bleeding continue to limit their uptake. Animal studies and experience from patients with genetic coagulation factor XI deficiency suggesting that this factor is more important for thrombosis than for haemostasis raises the potential for drugs that target factor XI to provide safer anticoagulation. Multiple factor XI inhibitors are currently under evaluation in clinical trials, including parenterally administered antisense oligonucleotides, monoclonal antibodies, and orally active small-molecule inhibitors. Promising results of phase 2 trials in patients undergoing major orthopaedic surgery, and in those with end-stage kidney disease, atrial fibrillation and acute coronary syndromes have led to large phase 3 trials that are currently ongoing. We here review premises for the use of these agents, results so far accrued, ongoing studies, and perspectives for future patient care.

Incidence and determinants of thrombotic and bleeding complications in patients with glioblastoma

BACKGROUND

Glioblastoma patients are considered to be at high risk of venous thromboembolism (VTE) and major bleeding (MB), although reliable incidence estimates are lacking. Moreover, the risk of arterial thromboembolism (ATE) in these patients is largely unknown. Our aim was to assess the cumulative incidence, predictors, and prognostic impact of VTE, ATE, and MB on subsequent complications and mortality.

METHODS

Cohort study of 967 consecutive patients diagnosed with glioblastoma between 2004-2020 in two hospitals. Patients were followed from 6 months before date of histopathological glioblastoma diagnosis up to 2 years after, or until an outcome of interest (VTE, ATE, and MB) or death occurred, depending on the analysis. Cumulative incidences were estimated with death as competing risk. Cox regression was used to identify predictors and the prognostic impact.

RESULTS

A total of 101 patients were diagnosed with VTE, 50 with ATE, and 126 with MB during a median follow-up of 15 months (interquartile range 9.0-22). The adjusted 1-year cumulative incidence of VTE was 7.5% (95% confidence interval [CI] 5.9-9.3), of ATE 4.1% (95% CI 3.0-5.6), and of MB 12% (95% CI 9.6-14). Older age, type of surgery, and performance status were predictors of VTE. Incident VTE during follow-up was associated with MB (adjusted HR 4.7, 95% CI 2.5-9.0). MB and VTE were associated with mortality (adjusted HR 1.7, 95% CI 1.3-2.1 and 1.3, 95% CI 1.0-1.7, respectively).

CONCLUSION

We found considerable incidences of VTE and MB in glioblastoma patients, with both complications associated with poorer prognosis. Our observations emphasize the need for prospective studies to determine optimal thromboprophylaxis and VTE treatment strategy in these patients.

An update on the global use of risk assessment models and thromboprophylaxis in hospitalized patients with medical illnesses from the World Thrombosis Day steering committee: Systematic review and meta-analysis

INTRODUCTION

Venous thromboembolism (VTE) is a leading cause of cardiovascular morbidity and mortality. The majority of VTE events are hospital-associated. In 2008, the Epidemiologic International Day for the Evaluation of Patients at Risk for Venous Thromboembolism in the Acute Hospital Care Setting (ENDORSE) multinational cross-sectional study reported that only approximately 40% of medical patients at risk of VTE received adequate thromboprophylaxis.

METHODS

In our systematic review and meta-analysis, we aimed at providing updated figures concerning the use of thromboprophylaxis globally. We focused on: (a) the frequency of patients with an indication to thromboprophylaxis according with individual models; (b) the use of adequate thromboprophylaxis; and (c) reported contraindications to thromboprophylaxis. Observational nonrandomized studies or surveys focusing on medically ill patients were considered eligible.

RESULTS

After screening, we included 27 studies from 20 countries for a total of 137 288 patients. Overall, 50.5% (95% confidence interval [CI]: 41.9-59.1, I2 99%) of patients had an indication to thromboprophylaxis: of these, 54.5% (95% CI: 46.2-62.6, I2 99%) received adequate thromboprophylaxis. The use of adequate thromboprophylaxis was 66.8% in Europe (95% CI: 50.7-81.1, I2 98%), 44.9% in Africa (95% CI: 31.8-58.4, I2 96%), 37.6% in Asia (95% CI: 25.7-50.3, I2 97%), 58.3% in South America (95% CI: 31.1-83.1, I2 99%), and 68.6% in North America (95% CI: 64.9-72.6, I2 96%). No major differences in adequate thromboprophylaxis use were found across risk assessment models. Bleeding, thrombocytopenia, and renal/hepatic failure were the most frequently reported contraindications to thromboprophylaxis.

CONCLUSIONS

The use of anticoagulants for VTE prevention has been proven effective and safe, but thromboprophylaxis prescriptions are still unsatisfactory among hospitalized medically ill patients around the globe with marked geographical differences.