The clinical efficacy of dabigatran etexilate for preventing stroke in atrial fibrillation patients

Effects of uninterrupted dabigatran on the intensity of anticoagulation during atrial fibrillation ablation

Background

Uninterrupted dabigatran during atrial fibrillation (AF) ablation is now established as the standard therapy. However, there are few reports on the effects of uninterrupted dabigatran on the intensity of anticoagulation during AF ablation.

Methods

We retrospectively analyzed 247 consecutive patients who underwent AF ablation in our hospital from January 2017 to December 2018. Patients who took warfarin or uninterrupted direct oral anticoagulants (DOACs) except for dabigatran were excluded. 89 patients underwent ablation with uninterrupted dabigatran (uninterrupted group, male 71, mean age 59.6 ± 14.0) and 124 with interrupted DOACs (interrupted group, male 105, mean age 56.9 ± 12.9) during AF ablation. The initial ACT level, proportion of ACT levels of more than 300 s, and total amount of heparin were compared. Furthermore, the incidence of procedure complications was also evaluated.

Results

The initial ACT levels were significantly higher in the uninterrupted group, and the total number of ACTs of more than 300 s was significantly higher in the uninterrupted group (uninterrupted vs. interrupted; initial ACT level, 315.6 ± 59.8 vs. 264.5 ± 48.6, p < .001; total number of ACTs ≧300, n [%], 304/ 484 [62.8 %] vs. 372/745 [49.9%], p < .001). The total amount of heparin during procedure was significantly lower in the uninterrupted group (uninterrupted group vs. interrupted group; 12966 ± 4773 vs. 16371 ± 5212, p < .001). There was no significant difference in the incidence of complications between the two groups.

Conclusions

In the catheter ablation of AF, uninterrupted dabigatran would be useful to obtain a stable anticoagulation status during the entire procedure.

Dabigatran Etexilate Induces Cytotoxicity in Rat Gastric Epithelial Cell Line via Mitochondrial Reactive Oxygen Species Production

Dabigatran is a novel oral anticoagulant that directly inhibits free and fibrin-bound thrombins and exerts rapid and predictable anticoagulant effects. While the use of this reagent has been associated with an increased risk of gastrointestinal bleeding, the reason why dabigatran use increases gastrointestinal bleeding risk remains unknown. We investigated the cytotoxicity of dabigatran etexilate and tartaric acid, the two primary components of dabigatran. The cytotoxicity of dabigatran etexilate and tartaric acid was measured in a cell viability assay. Intracellular mitochondrial reactive oxygen species (mitROS) production and lipid peroxidation were measured using fluorescence dyes. Cell membrane viscosity was measured using atomic force microscopy. The potential of ascorbic acid as an inhibitor of dabigatran cytotoxicity was also evaluated. The cytotoxicity of dabigatran etexilate was higher than that of tartaric acid. Dabigatran etexilate induced mitROS production and lipid peroxidation and altered the cell membrane viscosity. Ascorbic acid inhibited the cytotoxicity and mitROS production induced by dabigatran etexilate. Therefore, we attributed the cytotoxicity of dabigatran to dabigatran etexilate, and proposed that the cytotoxic effects of dabigatran etexilate are mediated via mitROS production. Additionally, we demonstrated that dabigatran cytotoxicity can be prevented via antioxidant treatment.

A comprehensive appraisal of dabigatran etexilate clinical evidence and applications: a 10-year-long story

During the last decade, non-vitamin K antagonist oral anticoagulants (NOACs) revolutionized the thromboprophylaxis management of several medical conditions, including atrial fibrillation and venous thromboembolism. Dabigatran etexilate was the first NOAC widely available worldwide, and it is currently the only one that directly inhibits thrombin. More recently, the availability of idarucizumab, a specific reversal agent, has increased the safety of dabigatran use in clinical practice, especially for those patients with severe and life-threatening bleeding. This review aims to summarize current evidence on dabigatran, starting from its pharmacological characteristics, and providing an updated overview of pivotal randomized controlled trials and real-world data on its efficacy and safety.

Trends in physiological coagulation factors in Japanese patients receiving novel oral anticoagulants

Background

Little is known about physiological anticoagulation effects via antithrombin III (AT III) and protein C/S (PC/PS) in patients using new oral anticoagulants (NOACs).

Methods

We evaluated 120 consecutive patients with non-valvular atrial fibrillation (AF) receiving NOACs. Patients were randomly divided into three groups: a dabigatran group (DG, N=40), a rivaroxaban group (RG, N=40) or an apixaban group (AG, N=40). A warfarin group (WG, N=40) was matched with NOAC groups for age, sex and type of AF during the same time period. Blood samples were obtained in pretreatment, trough and peak phases to measure the activity of physiological coagulation inhibitors, including AT III and PC/PS or thrombus formation markers such as D-dimer and thrombin–antithrombin complex (TAT).

Results

D-dimer, TAT and AT III values for the NOAC groups were equivalent in the peak and trough phases. PC/PS activity in both phases was equally maintained in the pretreatment phase in the NOAC groups, while the activity in the WG was significantly suppressed in steady state. Moreover, no differences in trends for PC/PS activity were observed among NOAC groups.

Conclusions

PC/PS activity was constant in both peak and trough phases in the patients on NOACs compared with activity of those on warfarin. In addition, there was no difference in the findings among NOACs.

Cost-Effectiveness and Cost-Utility Analyses of Dabigatran Compared with Warfarin in Patients with Nonvalvular Atrial Fibrillation and Risk Factors for Stroke and Systemic Embolism within Brazilian Private and Public Health Care Systems Perspectives

OBJECTIVE

To analyze the cost-effectiveness and cost-utility of dabigatran compared with warfarin in patients with nonvalvular atrial fibrillation with moderate to high risk of ischemic stroke or systemic embolism and eligible for treatment with anticoagulants.

METHODS

Markov-based economic analysis was performed to estimate treatment costs and outcomes. Epidemiological and efficacy data were determined after a critical revision of the medical literature. Unit costs were taken from Brazilian official databases. Only direct medical costs were covered. Costs and benefits were discounted at a rate of 5% per year. Outcomes were expressed as life-year (LY) and quality-adjusted life-year (QALY).

RESULTS

Dabigatran use is cost-effective in terms of LY and QALY considering a willingness-to-pay threshold of 3 times gross domestic product per capita of 2010 (Brazilian real 57,048/US $24,275.74) per LY and QALY saved in both analyzed perspectives (private and public health care systems).

CONCLUSIONS

Dabigatran use improves patient survival and quality of life compared with warfarin. This represents the best therapeutic option in terms of cost and effectiveness in the prevention of ischemic stroke and systemic embolism in patients with nonvalvular atrial fibrillation.

Feasibility and safety of uninterrupted dabigatran therapy in patients undergoing ablation for atrial fibrillation

OBJECTIVE

Uninterrupted oral warfarin strategy has become the standard protocol to prevent complications during catheter ablation (CA) for the treatment of atrial fibrillation (AF). However, little is known about the safety and efficacy of uninterrupted dabigatran therapy in patients undergoing CA for AF. Therefore, this study investigated the safety and efficacy of uninterrupted dabigatran therapy and compared the findings with those for uninterrupted warfarin therapy.

METHODS

Bleeding and thromboembolic events during the periprocedural period were evaluated in 363 consecutive patients who underwent CA for AF at Nagoya University Hospital, and received uninterrupted dabigatran (n=173) or uninterrupted warfarin (n=190) for periprocedural anticoagulation.

RESULTS

A total of 27 (7%) patients experienced either bleeding or thromboembolic complications. Major bleeding complications occurred in 2 (1%) patients in the dabigatran group (DG) and 2 (1%) patients in the warfarin group (WG). Eight (5%) patients in the DG and 9 (5%) patients in the WG experienced groin hematoma, a type of minor bleeding complication. Meanwhile, no patient in the DG and 1 (1%) in the WG developed cerebral ischemic stroke. Overall, there was no significant difference between the groups for any category. The activated partial thromboplastin time (APTT) independently predicted periprocedural complications in the DG.

CONCLUSION

Uninterrupted dabigatran therapy in CA for AF thus may be a safe and effective anticoagulant therapy, and appears to be closely similar to continuous warfarin; however, it is essential to pay close attention to the APTT values when using dabigatran during CA.

Efficacy and safety of apixaban in the patients undergoing the ablation of atrial fibrillation

INTRODUCTION

Apixaban, a factor Xa (FXa) inhibitor, is a new oral anticoagulant for stroke prevention in atrial fibrillation (AF). However, little is known about its efficacy and safety as a periprocedural anticoagulant therapy for patients who had undergone catheter ablation (CA) for AF.

METHODS AND RESULTS

We evaluated 342 consecutive patients who underwent CA for AF between April 2013 and March 2014 and received apixaban (n = 105) and warfarin (n = 237) for uninterrupted periprocedural anticoagulation. We retrospectively investigated the occurrence of bleeding and thromboembolic complications during the procedural period and compared them between the apixaban group (AG) and warfarin group (WG). Thromboembolic complications occurred in one (0.4%) patient in the WG. Major and minor bleeding complications occurred in one (1%) and four (4%) patients in the AG, and three (1%) and 12 (5%) patients in the WG. No significant difference in complications was observed between the AG and WG. Of importance, adverse event rates did not differ between the two groups after adjusting by a propensity score analysis. In preoperative tests of blood coagulation, there were significant differences in the prothrombin time, activated partial thromboplastin time, FXa activity, and prothrombin fragment 1 + 2 (F1+2) levels between the AG and WG.

CONCLUSION

The use of apixaban during the periprocedural period of AF ablation seemed as efficacious and safe as warfarin.