Non-vitamin K oral anticoagulants (NOAC) and the risk of myocardial infarction: Differences between factor IIa and factor Xa inhibition?

Effect of Oral Anticoagulants in Atrial Fibrillation Patients with Polypharmacy: A Meta-analysis

BACKGROUND

 The aim of the present meta-analysis was to evaluate the effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) versus vitamin K antagonists (VKAs) in atrial fibrillation (AF) patients with polypharmacy.

METHODS AND RESULTS

 Randomized controlled trials or observational studies reporting the data of NOACs versus VKAs among AF patients with polypharmacy were included. The search was performed in the PubMed and Embase databases up to November 2022. A total of 12 studies involving 767,544 AF patients were included. For the primary outcomes, the use of NOACs compared with VKAs was significantly associated with a reduced risk of stroke or systemic embolism in AF patients with moderate polypharmacy (hazard ratio [HR]: 0.77 [95% confidence interval [CI]: 0.69-0.86]) and severe polypharmacy (HR: 0.76 [95% CI: 0.69-0.82]), but there was no significant difference in major bleeding (moderate polypharmacy: HR: 0.87 [95% CI: 0.74-1.01]; severe polypharmacy: HR: 0.91 [95% CI: 0.79-1.06]) between the two groups. In secondary outcomes, there were no differences in the rates of ischemic stroke, all-cause death, and gastrointestinal bleeding between the NOAC- and VKA- users, but NOAC users had a reduced risk of any bleeding compared with VKA- users. Compared with VKAs, the risk of intracranial hemorrhage was reduced in NOAC- users with moderate polypharmacy but not severe polypharmacy.

CONCLUSION

 In patients with AF and polypharmacy, NOACs showed advantages over VKAs in stroke or systemic embolism and any bleeding, and were comparable to VKAs for major bleeding, ischemic stroke, all-cause death, intracranial hemorrhage, and gastrointestinal bleeding.

AF-React study: Prevalence of thrombotic events in patients with atrial fibrillation receiving NOACs - real-world data analysis from northern Portugal primary healthcare

Introduction

Anticoagulation is recommended for stroke prevention in patients with atrial fibrillation (AF). The guidelines suggest non-vitamin K antagonist anticoagulants (NOACs) as the primary therapy for anticoagulation in AF. Several patient-related factors increase the risk of thrombotic events: elderly individuals, a previous history of stroke, and chronic kidney disease. This study aims to determine the association between NOACs and other patient variables in AF and the occurrence of thrombotic events.

Methods

The database included all adults with the code K78 (ICPC-2 code for AF) who received clinical care in Northern Portugal's Primary Health Care between January 2016 and December 2018 and were dispensed the same NOAC at the pharmacy.

Results

The results indicate that 10.2% of AF patients on NOAC anticoagulation experienced a stroke. Furthermore, patients treated with apixaban and dabigatran had higher odds of experiencing a stroke compared to those treated with rivaroxaban. Among patients with the same age, gender, and CHA2DS2Vasc Score, apixaban was significantly associated with a higher likelihood of thrombotic events than rivaroxaban.

Discussion

These results have not been previously reported in studies with real-world data; therefore, a more detailed analysis should be conducted to enhance the validity of these findings.

Effects of direct oral anticoagulants dabigatran and rivaroxaban on the blood coagulation function in rabbits

The aim of this study was to explore the effects of dabigatran and rivaroxaban on the activities of various coagulation factors. To achieve that, 60 rabbits were randomly divided into experimental groups that received different doses of dabigatran or rivaroxaban. The effects of dabigatran and rivaroxaban on the activities of FII, FV, FVIII, FX, and activated protein C (APC) were analyzed. In the dabigatran groups, activated partial thromboplastin time and thromboplastin time (TT) were prolonged after drug administration, and the activities of FII, FV, FVIII, and FX were inhibited as the drug concentration increased. Low doses of dabigatran inhibited APC activity. In the rivaroxaban groups, APTT and TT were not significantly prolonged after drug administration. In contrast, the high-dose rivaroxaban group exhibited prolonged PT, and the degree of inhibition of the activities of FII, FV, FVIII, and FX increased as the drug concentration increased. Rivaroxaban had no significant effect on APC activity regardless of dosage. As the drug concentration increased, both NOACs had more significant inhibitory effects on the activities of FII, FV, FVIII, and FX. Low concentrations of dabigatran generated an inhibitory effect on APC activity, while high concentrations of dabigatran had no significant effect. Rivaroxaban had no significant effect on APC activity.

Optimisation of oral anticoagulants for patients with atrial fibrillation within 12 months after percutaneous coronary intervention: A meta-analysis and systematic review

BACKGROUND

The optimal antithrombotic strategy, especially regarding oral anticoagulants (OACs) for atrial fibrillation (AF) patients with bleeding and thrombosis risk after percutaneous coronary intervention (PCI), remains unknown. This study explored the optimal oral anticoagulants for AF patients after PCI using a meta-analysis.

METHODS

Randomised controlled trials were identified from PubMed, Embase, and the Cochrane Library through December 2020. Risk ratios, 95% confidence intervals, and random-effects models were used to compare different antithrombotic strategies through network meta-analysis, and the combination of antithrombotic agents was ranked according to the surface under the cumulative ranking curve and rankograms. Interval plots were drawn to observe pairwise comparisons between the different strategies.

RESULTS

Five studies of 11,532 patients were included. Factor IIa inhibitor 110 mg bid plus a P2Y12 inhibitor had the greatest advantage for reducing Thrombolysis In Myocardial Infarction (TIMI) major or minor bleeding; Factor Xa inhibitor plus a P2Y12 inhibitor had the greatest advantage for reducing International Society on Thrombosis and Hemostasis major bleeding. For patients at risk of stroke plus all-cause death, factor IIa inhibitor 150 mg bid plus a P2Y12 inhibitor should be prioritised, and for those at risk of myocardial infarction and stent thrombosis, vitamin K antagonists plus a P2Y12 inhibitor were preferred.

CONCLUSION

Factor IIa inhibitor 110 mg, factor IIa inhibitor 150 mg, factor Xa inhibitor and vitamin K antagonists should be selected in different situations.

Different DOACs Control Inflammation in Cardiac Ischemia-Reperfusion Differently

RATIONALE

While thrombin is the key protease in thrombus formation, other coagulation proteases, such as fXa (factor Xa) or aPC (activated protein C), independently modulate intracellular signaling via partially distinct receptors.

OBJECTIVES

To study the differential effects of fXa or fIIa (factor IIa) inhibition on gene expression and inflammation in myocardial ischemia-reperfusion injury.

METHODS AND RESULTS

Mice were treated with a direct fIIa inhibitor (fIIai) or direct fXa inhibitor (fXai) at doses that induced comparable anticoagulant effects ex vivo and in vivo (tail-bleeding assay and FeCl3-induced thrombosis). Myocardial ischemia-reperfusion injury was induced via left anterior descending ligation. We determined infarct size and in vivo aPC generation, analyzed gene expression by RNA sequencing, and performed immunoblotting and ELISA. The signaling-only 3K3A-aPC variant and inhibitory antibodies that blocked all or only the anticoagulant function of aPC were used to determine the role of aPC. Doses of fIIai and fXai that induced comparable anticoagulant effects resulted in a comparable reduction in infarct size. However, unbiased gene expression analyses revealed marked differences, including pathways related to sterile inflammation and inflammasome regulation. fXai but not fIIai inhibited sterile inflammation by reducing the expression of proinflammatory cytokines (IL [interleukin]-1β, IL-6, and TNFα [tumor necrosis factor alpha]), as well as NF-κB (nuclear factor kappa B) and inflammasome activation. This anti-inflammatory effect was associated with reduced myocardial fibrosis 28 days post-myocardial ischemia-reperfusion injury. Mechanistically, in vivo aPC generation was higher with fXai than with fIIai. Inhibition of the anticoagulant and signaling properties of aPC abolished the anti-inflammatory effect associated with fXai, while inhibiting only the anticoagulant function of aPC had no effect. Combining 3K3A-aPC with fIIai reduced the inflammatory response, mimicking the fXai-associated effect.

CONCLUSIONS

We showed that specific inhibition of coagulation via direct oral anticoagulants had differential effects on gene expression and inflammation, despite comparable anticoagulant effects and infarct sizes. Targeting individual coagulation proteases induces specific cellular responses unrelated to their anticoagulant effect.

Synthesis, Docking, and In Vitro Anticoagulant Activity Assay of Hybrid Derivatives of Pyrrolo[3,2,1-ij]Quinolin-2(1H)-one as New Inhibitors of Factor Xa and Factor XIa

Coagulation factor Xa and factor XIa are proven to be convenient and crucial protein targets for treatment for thrombotic disorders and thereby their inhibitors can serve as effective anticoagulant drugs. In the present work, we focused on the structure–activity relationships of derivatives of pyrrolo[3,2,1-ij]quinolin-2(1H)-one and an evaluation of their activity against factor Xa and factor XIa. For this, docking-guided synthesis of nine compounds based on pyrrolo[3,2,1-ij]quinolin-2(1H)-one was carried out. For the synthesis of new hybrid hydropyrrolo[3,2,1-ij]quinolin-2(1H)-one derivatives, we used convenient structural modification of both the tetrahydro- and dihydroquinoline moiety by varying the substituents at the C^6,8,9 positions. In vitro testing revealed that four derivatives were able to inhibit both coagulation factors and three compounds were selective factor XIa inhibitors. An IC₅₀ value of 3.68 μM for was found for the best factor Xa inhibitor and 2 μM for the best factor XIa inhibitor.

Vascular protease-activated receptor 4 upregulation, increased platelet aggregation, and coronary lipid deposits induced by long-term dabigatran administration - results from a diabetes animal model

Essentials The impact of long-term thrombin inhibition outside the coagulation cascade is far from clear. We aimed to assess the impact of dabigatran etexilate (DE) in diabetic and control rats. In diabetic rats, DE increased platelet aggregation and lead to coronary lipid deposits. Long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk. SUMMARY: Background Besides its role in the coagulation cascade, thrombin contributes to platelet aggregation and to a plethora of non-hemostatic functions. Objectives To assess the impact of long-term thrombin inhibition with dabigatran etexilate (DE) on platelet aggregation and on extrahemostatic thrombin-related functions in diabetic and control rats. Methods Markers of inflammation, endothelial dysfunction, oxidative stress, angiogenesis and cell adhesion molecules were quantified in control rats (Control; n = 6), DE-treated control rats (Control-Dabi; n = 8), diabetic rats (Diabetes; n = 5), and DE-treated diabetic rats (Diabetes-Dabi; n = 8). Agonist-induced platelet aggregation, aortic and coronary lipid deposits and aortic protease-activated receptor 4 (PAR4) expression were also assessed. Results Control-Dabi rats showed significantly higher high-sensitivity C-reactive protein, von Willebrand factor (VWF), vascular endothelial growth factor (VEGF) and fibronectin levels, and significantly lower PAR4 agonist-induced aggregation, than Control rats. Control-Dabi rats also showed mild aortic lipid deposits, whereas no such changes were observed in Control rats. Diabetes-Dabi rats showed significantly higher VWF, VEGF and fibronectin levels than Diabetes rats, and similar PAR4 agonist-induced aggregation as Diabetes rats, and significantly higher ADP-induced aggregation than Diabetes rats. Coronary lipid deposits were observed in 75% of Diabetes-Dabi rats and in none of the Diabetes rats. PAR4 expression was 20.4% higher in Control-Dabi rats and 27.4% higher in Diabetes-Dabi rats than in their non-treated peers. Conclusions This study indicates that long-term thrombin inhibition increases vascular PAR4 expression, promotes atherosclerosis-related mechanisms, and, in diabetic rats, increases platelet aggregation and favors the occurrence of coronary lipid deposits. These experimental data suggest that long-term thrombin inhibition may increase atherosclerotic and atherothrombotic risk, particularly in the presence of diabetes.