The risk of gastrointestinal hemorrhage with non-vitamin K antagonist oral anticoagulants: A network meta-analysis

[Use of specific antidotes in DOAC-associated severe gastrointestinal bleeding - an expert consensus - Antagonozation of direct oral anticoagulants in gastrointestinal hemorrhages]

Gastrointestinal (GI) bleeding is one of the most common complications associated with the use of direct oral anticoagulants (DOAC). Clear algorithms exist for the emergency measures in (suspected) GI bleeding, including assessing the medication history regarding anti-platelet drugs and anticoagulants as well as simple coagulation tests during pre-endoscopic management. Platelet transfusions, fresh frozen plasma (FFP), or prothrombin complex concentrate (4F-PCC) are commonly used for optimizing the coagulation status. For severe bleeding under the thrombin inhibitor dabigatran, idarucizumab is available, and for bleeding under the factor Xa inhibitors rivaroxaban or apixaban, andexanet alfa is available as specific antidotes for DOAC antagonization. These antidotes represent emergency drugs that are typically used only after performing guideline-compliant multimodal measures including emergency endoscopy. Antagonization of oral anticoagulants should be considered for severe gastrointestinal bleeding in the following situations: (1) refractory hemorrhagic shock, (2) endoscopically unstoppable bleeding, or (3) nonavoidable delays until emergency endoscopy for life-threatening bleeding. After successful (endoscopic) hemostasis, anticoagulation (DOACs, vitamin K antagonist, heparin) should be resumed timely (i.e. usually within a week), taking into account individual bleeding and thromboembolic risk.

Effectiveness and Safety of Different Oral Anticoagulants with P-glycoprotein/ CYP3A4 Inhibitors: A Network Meta-analysis

BACKGROUND

Metabolism of oral anticoagulants (OAC) is affected by P-glycoprotein (P-gp)/ CYP3A4 enzyme. However, the P-gp/CYP3A4 inhibitors are unavoidably used with OACs.

METHODS

Medline, Cochrane, and Embase were systematically searched for randomized controlled trials and cohort studies from inception till 23rd November, 2022 to assess the safety and effectiveness of OACs when concomitantly used with P-gp/CYP3A4 inhibitors. The primary outcomes were major bleeding and gastrointestinal (GI) bleeding. Secondary outcomes were stroke/systemic embolism (SE), all-cause mortality, any bleeding as well as intracranial hemorrhage (ICH). We estimated summary odds ratios (OR) with 95% credible intervals (CI) using pairwise and network meta-analysis with random effects.

RESULTS

A total of 11 studies involving 37,973 patients were included. When concomitantly used with P-pg/ CYP3A4 inhibitors, network meta-analysis indicated that dabigatran, apixaban, and edoxaban were associated with significantly lower risk of major bleeding compared to rivaroxaban, with ORs of 0.56, 0.51 and 0.48, respectively. Rivaroxaban and dabigatran were associated with a significantly increased risk of GI bleeding than warfarin, apixaban and edoxaban. Dabigatran and apixaban were linked with significantly lower risk of any bleeding compared with warfarin (ORs were 0.75 and 0.68, respectively) or rivaroxaban (ORs were 0.67 and 0.60, respectively). Apixaban (OR 0.32) and edoxaban (OR 0.35) were associated with a lower risk of ICH compared with warfarin. There was no difference between any OACs in terms of stroke/SE or all-cause mortality.

CONCLUSION

When concomitantly used with P-gp/CYP3A4 inhibitors, apixaban and edoxaban were associated with a lower risk of bleeding, though no significant difference in effectiveness was observed among all OACs.

Safety of Direct Oral Anticoagulants for Gastrointestinal Hemorrhage in Patients With Nonvalvular Atrial Fibrillation: A Systematic Review and Meta-analysis of Real-world Studies

GOALS AND BACKGROUND

Since the introduction of Direct Oral Anticoagulants (DOACs), "real-world" studies have investigated their safety profile on gastrointestinal hemorrhage (GIH) when used by patients with Non-Valvular Atrial Fibrillation. We performed a systematic review and meta-analysis to compile and summarize this data after Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.

STUDY

Medline and Embase were systematically searched until April 2021. Observational studies that met predefined inclusion criteria were included and hazard ratios (HRs) with 95% CI were extracted. Subgroup analyses based on DOAC doses, history of chronic kidney disease, stroke, prior exposure to VKA (vitamin K antagonist), age, gender, geographic location of population samples, as well as Leave-One-Out and Low/Moderate Risk of Bias sensitivity analyses were performed. A random effects model was used.

RESULTS

A total of 46 studies were included. Apixaban was associated with a reduced risk of GIH compared with Dabigatran (HR: 0.67, 95% CI, 0.56 to 0.81, I2 : 53.28%), Rivaroxaban (HR: 0.56, 95% CI, 0.44 to 0.70, I2 : 79.17%), and VKA (HR: 0.68, 95% CI, 0.60 to 0.78, I2 : 71.93%). Rivaroxaban was associated with increased GIH risk compared with Dabigatran (HR: 1.19, 95% CI, 1.02 to 1.40, I2 : 72.96%) and VKA (HR: 1.16, 95% CI, 1.05 to 1.27, I2 : 81.95%). Dabigatran was associated with similar GIH risk compared with VKA (HR: 1.11, 95% CI, 0.98 to 1.26, I2 : 87.28%).

CONCLUSIONS

Our study shows that Apixaban was associated with a reduction in GIH risk compared with Dabigatran, Rivaroxaban and VKA, whereas Rivaroxaban was associated with an increase in GIH risk compared with both Dabigatran and VKA.

Potential anticoagulant of traditional chinese medicine and novel targets for anticoagulant drugs

BACKGROUND

Anticoagulants are the main drugs used for the prevention and treatment of thrombosis. Currently, anticoagulant drugs are primarily multitarget heparin drugs, single-target FXa inhibitors and FIIa inhibitors. In addition, some traditional Chinese drugs also have anticoagulant effects, but they are not the main direction of treatment at present. But the anticoagulant drugs mentioned above, all have a common side effect is bleeding. Many other anticoagulation targets are under investigation. With further exploration of coagulation mechanism, how to further determine new anticoagulant targets and how to make traditional Chinese medicine play anticoagulant role have become a new field of exploration.

PURPOSE

The purpose of the study was to summarize the recent research progress on coagulation mechanisms, new anticoagulant targets and traditional Chinese medicine.

METHODS

A comprehensive literature search was conducted using four electronic databases, including PubMed, Embase, CNKI, Wanfang database and ClinicalTrials.gov, from the inception of the study to 28 Feb 2023. Key words used in the literature search were "anticoagulation", "anticoagulant targets", "new targets", "coagulation mechanisms", "potential anticoagulant", "herb medicine", "botanical medicine", "Chinese medicine", "traditional Chinese medicine", "blood coagulation factor", keywords are linked with AND/OR. Recent findings on coagulation mechanisms, potential anticoagulant targets and traditional Chinese medicine were studied.

RESULTS

The active components extracted from the Chinese medicinal herbs, Salvia miltiorrhiza, Chuanxiong rhizoma, safflower and Panax notoginseng have obvious anticoagulant effects and can be used as potential anticoagulant drugs, but the risk of bleeding is unclear. TF/FVIIa, FVIII, FIX, FXI, FXII, and FXIII have all been evaluated as targets in animal studies or clinical trials. FIX and FXI are the most studied anticoagulant targets, but FXI inhibitors have shown stronger advantages.

CONCLUSION

This review of potential anticoagulants provides a comprehensive resource. Literature analysis suggests that FXI inhibitors can be used as potential anticoagulant candidates. In addition, we should not ignore the anticoagulant effect of traditional Chinese medicine, and look forward to more research and the emergence of new drugs.

Antithrombotics and Gastrointestinal Prophylaxis: A Systematic Review

Antithrombotic medications include both antiplatelet and anticoagulants and are used for a wide variety of cardiovascular conditions. A common complication of antithrombotic use is gastrointestinal bleeding. As a result, gastrointestinal prophylaxis is a common consideration for patients on a single or combination antithrombotic regimen. Prophylaxis is typically achieved through use of either proton pump inhibitors or histamine 2 receptor antagonists. Current recommendations for use of gastrointestinal prophylaxis with concomitant use of antithrombotic medications are scarce. In this systematic review, we explore the current evidence and recommendations regarding gastrointestinal prophylaxis for patients on antiplatelet or anticoagulant therapy as well as combination regimens.

Economic Evaluation of Direct Oral Anticoagulants Compared to Warfarin for Venous Thromboembolism in Thailand: A Cost-Utility Analysis

BACKGROUND

Direct oral anticoagulants (DOACs) have been used for venous thromboembolism (VTE) in Thailand. However, they have not been listed in the National List of Essential Medicines (NLEM). A cost-effectiveness analysis is needed to aid policymakers in deciding whether DOACs should be listed in the NLEM. This study aimed to assess the cost-effectiveness of DOACs for patients with VTE in Thailand.

METHODS

A cohort-based state transition model was constructed from a societal perspective with a lifetime horizon. All available DOACs, including apixaban, rivaroxaban, edoxaban, and dabigatran, were compared with warfarin. A 6-month cycle length was used to capture all costs and health outcomes. The model consisted of nine health states, including VTE on treatment, VTE off treatment, recurrent VTE, clinically relevant non-major bleeding, gastrointestinal bleeding, intracranial bleeding, post-intracranial bleeding, chronic thromboembolic pulmonary hypertension, and death. All inputs were based on a comprehensive literature review. The model outcomes included total cost and quality-adjusted life-years (QALYs) with a 3% annual discount rate. A fully incremental cost-effectiveness analysis and the incremental cost-effectiveness ratio (ICER) per QALY gained were calculated at a willingness-to-pay (WTP) of THB 160,000/QALY ($5003). The robustness of the findings was assessed using deterministic and probabilistic sensitivity analyses.

RESULTS

All DOACs were associated with a decreased risk of VTE recurrence and intracranial hemorrhage. In the base-case analysis, apixaban could increase 0.16 QALYs compared with warfarin. An ICER for apixaban was 269,809 Thai baht (THB)/QALY ($8437/QALY). Rivaroxaban had a better QALY than warfarin at 0.09 QALYs with an ICER of 757,363 THB/QALY ($23,682/QALY). Edoxaban and dabigatran could also increase by 0.10 QALYs with an ICER of 709,945 THB ($22,200) and 707,145 THB ($22,122)/QALY, respectively. Our probabilistic sensitivity analyses indicated that warfarin had a 99.8% possibility of being cost-effective, while apixaban had a 0.2% possibility of being cost-effective at the current WTP. Other DOACs had no possibility of being cost-effective.

CONCLUSIONS

All DOACs were not cost-effective for VTE treatment at the current WTP in Thailand. Apixaban is likely to be the best option among DOACs.

The Role of Direct Oral Anticoagulants in Cancer-Associated Thrombosis According to the Current Literature

Venous thromboembolism (VTE) is a common complication among patients suffering from malignancies, leading to an increased mortality rate. Novel randomized trials have added valuable information regarding cancer-associated thrombosis (CAT) management using direct oral anticoagulants (DOACs). The aim of this study is to present an overview of the current literature and recommendations in CAT treatment. A few randomized control trials (RCTs) have been integrated suggesting that DOACs may be effectively applied in CAT patients compared to low molecular weight heparins (LMWHs) with a decreased mortality and VTE recurrence rate. However, the risk of bleeding is higher, especially in patients with gastrointestinal malignancies. Real-world data are in accordance with these RCT findings, while in the currently available recommendations, DOACs are suggested as a reliable alternative to LMWH during the initial, long-term, and extended phase of treatment. Data retrieved from the current literature, including RCTs and “real-world” studies, aim to clarify the role of DOACs in CAT management, by highlighting their benefits and remarking upon the potential adverse outcomes. Current recommendations suggest the use of DOACs in well-selected patients with an increasing level of evidence through years.