Dose-escalation study of the pharmacokinetics and pharmacodynamics of rivaroxaban in healthy elderly subjects

Association between oral anticoagulant therapy and in-hospital complications and mortality

AIMS

This study aimed to identify patterns of direct oral anticoagulant (DOAC) and vitamin K antagonist (VKA) use in hospitalized patients and to examine their association with in-hospital haemorrhagic complications and mortality.

METHODS

An observational cross-sectional study was conducted among hospitalized patients ≥18 years from 2018 to 2022. Data on hospital discharges were obtained from the minimum data set and were matched with pharmacy records to identify patients treated with DOACs or VKAs. In-hospital haemorrhagic complications and mortality rates were calculated for study groups. Multivariate logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95%CIs), adjusting for age, sex and comorbidities. Analyses were stratified by medical and surgical profiles. Statistical significance was set at .05.

RESULTS

The study included 74 190 patients, with 4774 receiving DOACs and 1768 VKAs. During the study period, DOAC use increased by 45.11%. DOAC-treated patients had lower complication rates than those treated with VKAs (1.9 vs. 2.8%, respectively; P = .032). DOAC use was linked to a lower risk of haemorrhagic complications in surgical patients (OR = 0.65; 95%CI: 0.35-0.91), while in medical patients, the reduction in risk was not statistically significant (OR = 0.59; 95%CI: 0.33-1.10). No effect on mortality risk was observed among medical and surgical patients.

CONCLUSIONS

The increased use of DOACs among hospitalized patients showed a protective effect against haemorrhagic complications in surgical patients, supporting their increasing use in hospital settings.

Key Factors for Improving Predictive Accuracy and Avoiding Overparameterization of the PBPK Absorption Model in Food Effect Studies of Weakly Basic Water-Insoluble Compounds in Immediate Release Formulations

Background/Objectives: Physiologically based pharmacokinetic (PBPK) absorption models are instrumental for assessing drug absorption prior to clinical food effect studies, though discrepancies in predictive and actual outcomes are observed. This study focused on immediate release formulations of weakly basic water-insoluble compounds, namely rivaroxaban, ticagrelor, and PB-201, to investigate factors that could improve the predictive accuracy of PBPK models regarding food effects. Methods: Comprehensive in vitro experimental results provided the basis for the development of mechanistic absorption models, which were then combined with mechanistic disposition models to predict the systemic exposure of the model drugs in both fasted and fed states. Results: The developed PBPK models showed moderate to high predictive accuracy for food effects in Caucasian populations. For the Chinese population, the ticagrelor model's initial overestimation of fed-state absorption was addressed by updating the permeability parameters from Caco-2 cell assays to those derived from parallel artificial membrane permeability assays in FaSSIF and FeSSIF media. This refinement was also applied to the rivaroxaban and ticagrelor models, leading to a more accurate representation of absorption in Caucasians. Conclusions: This study highlights the importance of apparent permeability in enhancing the predictive accuracy of PBPK absorption models for weakly basic water-insoluble compounds. Furthermore, the precipitation of PB-201 in the two-stage transfer experiments suggests that precipitation may not be a universal phenomenon for such compounds in vivo. Consequently, the precipitation rate constant, a theoretically essential parameter, should be determined based on experimental evidence to avoid overparameterization and ensure robust predictive accuracy of PBPK models.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Nomogram for predicting bleeding events in nonvalvular atrial fibrillation patients receiving rivaroxaban: A retrospective study

Background and Aims

To construct a bleeding events prediction model of nonvalvular atrial fibrillation (NVAF) patients receiving rivaroxaban.

Methods

We conducted a retrospective cohort study in patients with NVAF who received rivaroxaban from June 2017 to March 2019. Demographic information and clinical characteristics were obtained from the electronic medical system. Univariate analysis was used to find the primary predictive factors of bleeding events in patients receiving rivaroxaban. Multiple analysis was conducted to screen the primary independent predictive factors selected from the univariate analysis. Finally, the independent influencing factors were applied to build a prediction model by using R software; then, a nomogram was established according to the selected variables visually, and the sensitivity and specificity of the model was evaluated.

Results

Twelve primary predictive factors were selected by univariate analysis from 46 variables, and multivariate analysis showed that older age, higher prothrombin time (PT) values, history of heart failure and stroke were independent risk factors of bleeding events. The area under curve (AUC) for this novel nomogram model was 0.828 (95% CI: 0.763-0.894). The mean AUC over 10-fold stratified cross-validation was 0.787, and subgroup analysis validation also showed a satisfied AUC. In addition, the decision curve analysis showed that the PT in combination with CHA2DS2-VASc and HASBLED was more practical and accurate for predicting bleeding events than using CHA2DS2-VASc and HASBLED alone.

Conclusions

PT in combination with CHA2DS2-VASc and HASBLED could be considered as a more practical and accurate method for predicting bleeding events in patients taking rivaroxaban.

Platelet-rich fibrin ensures hemostasis after single-tooth removal under factor Xa inhibitors - a clinical prospective randomized split-mouth study

OBJECTIVES

In this prospective, double-blinded, randomized split-mouth study, the local hemostatic effect of platelet-rich fibrin (PRF) inserted into the extraction socket in patients taking factor Xa (FXa) inhibitors (apixaban, rivaroxaban, edoxaban) was compared to a hemostatic gelatine sponge (GS) as the "therapeutic gold standard" without withdrawal of oral anticoagulant therapy.

MATERIALS AND METHODS

Single-tooth extraction was conducted under local anesthesia in n = 21 patients using a split-mouth design (42 teeth). Using a double-blind approach, the extraction socket on one side of the jaw was filled with PRF and on the other with a GS. Bleeding was assessed immediately after surgery, in 30 min, 1 h, 1.5 h, and on follow-up appointments in 24 h and on the 7th day.

RESULTS

In 67% of cases, mild postoperative oozing could be stopped 30-90 min after tooth extraction via gauze pressure without any delayed bleeding. Concerning bleeding events, there was no difference among the PRF and GS groups and no significant difference among rivaroxaban, apixaban, and edoxaban (all p > 0.15).

CONCLUSION

PRF and GS are reliable hemostatic methods in postextraction sockets of patients taking FXa inhibitors.

CLINICAL RELEVANCE

Consequently, there is no need to discontinue FXa inhibitors because of a single-tooth removal, eliminating the risk of thrombus formation.

In vivo evaluation of the pharmacokinetic interactions between almonertinib and rivaroxaban, almonertinib and apixaban

Background: Almonertinib, a third-generation epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI), is commonly used as a first-line treatment for non-small cell lung cancer (NSCLC) patients with EGFR T790M mutations. Rivaroxaban and apixaban are a selective, direct factor Xa inhibitor used to treat venous thromboembolism (VTE), which is a frequent complication of NSCLC. Rivaroxaban and apixaban are substrates of CYP3A4, P-gp and BCRP, whereas almonertinib is an inhibitor of P-gp and BCRP. Rivaroxaban or apixaban are often prescribed together with almonertinib in NSCLC patients, but clear information on pharmacokinetic drug interaction is lacking. Therefore, this study aimed to unravel the extent of interactions between almonertinib-rivaroxaban and almonertinib apixaban in rats, and whether the pharmacokinetic interaction can be mitigated by rivaroxaban and apixaban dose adjustment. Methods: Rats were divided into ten groups (n = 6) that received rivaroxaban (2 mg/kg) (group 1), apixaban (0.5 mg/kg) (group 2), almonertinib (15 mg/kg) (group 3, group 4), almonertinib with rivaroxaban (2 mg/kg) (group 5), almonertinib with rivaroxaban (1 mg/kg) (group 6), almonertinib with apixaban (0.5 mg/kg) (group 7), almonertinib with apixaban (0.25 mg/kg) (group 8), rivaroxaban (2 mg/kg) with almonertinib (group 9), apixaban (0.5 mg/kg) with almonertinib (group 10). The concentrations of drugs were determined by an ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The levels of messenger RNA were determined using quantitative real-time polymerase chain reaction (qRT-PCR). Results and Discussion: The results indicate that almonertinib increased the Cmax and AUC0-t of 2 mg/kg rivaroxaban by 3.30 and 3.60-fold, 1 mg/kg rivaroxaban by 1.28 and 1.90-fold. Almonertinib increased the Cmax and AUC0-t of 0.5 mg/kg apixaban by 2.69 and 2.87-fold, 0.25 mg/kg apixaban by 2.19 and 2.06-fold. In addition, rivaroxaban also increased systemic exposure to almonertinib. The results of qRT-PCR showed that almonertinib reduced the expression of Cyp3a1 in liver and intestine, and Abcb1a, Abcg2 in intestine and kidney. The pharmacokinetic results suggest that it is important to take special care of the interactions of these drugs in clinical applications.

Electrochemically Enabled Total Syntheses of Natural Products

Electrochemical techniques have helped to enable the total synthesis of natural products since the pioneering work of Kolbe in the mid 1800's. The electrochemical toolset grows every day and these new possibilities change the way chemists look at and think about natural products. This review provides a perspective on total syntheses wherein electrochemical techniques enabled the carbon─carbon bond formations in the skeletal assembly of important natural products, discussion of mechanistic details, and representative examples of the bond formations enabled over the last several decades. These bond formations are often distinctly different from those possible with conventional chemistries and allow assemblies complementary to other techniques.

Direct Oral Anticoagulants: An Updated Systematic Review of Their Clinical Pharmacology and Clinical Effectiveness and Safety in Patients With Nonvalvular Atrial Fibrillation

Direct oral anticoagulants have been an increasingly used class of drugs in the setting of nonvalvular atrial fibrillation, defying vitamin K antagonists' monopoly when it comes to anticoagulation due to its several limitations. Direct oral anticoagulants (DOACs) have entered the market as a noninferior and safer option in comparison with vitamin K antagonists, as their respective phase III clinical trials proved. The aim of this article was to update and summarize data on their clinical pharmacology and to review real-world data to know their comparative effectiveness and safety. We performed a systematic review using PubMed, Google Scholar, Embase, and Web of Science as search engines. Regarding pharmacodynamics, there were no substantial changes reported from their original profile. There were many advances in the knowledge about clinical pharmacokinetics of DOACs that have had a direct impact on their clinical use, mainly related to drug-drug interactions. In a real-world setting, DOACs have shown to be noninferior in preventing thromboembolic events compared to vitamin K antagonists. In regards to safety, DOACs have shown a lower bleeding risk relative to warfarin. Comparison between DOACs has demonstrated rivaroxaban to have the highest bleeding risk. Overall, the evidence gathered showed few changes from the original data presented in phase III clinical trials, concluding that their real-world use coincides greatly with them.

Assessment of DOAC in GEriatrics (Adage Study): Rivaroxaban/Apixaban Concentrations and Thrombin Generation Profiles in NVAF Very Elderly Patients

BACKGROUND

 Although a growing number of very elderly patients with atrial fibrillation (AF), multiple conditions, and polypharmacy receive direct oral anticoagulants (DOACs), few studies specifically investigated both apixaban/rivaroxaban pharmacokinetics and pharmacodynamics in such patients.

AIMS

 To investigate: (1) DOAC concentration-time profiles; (2) thrombin generation (TG); and (3) clinical outcomes 6 months after inclusion in very elderly AF in-patients receiving rivaroxaban or apixaban.

METHODS

 Adage-NCT02464488 was an academic prospective exploratory multicenter study, enrolling AF in-patients aged ≥80 years, receiving DOAC for at least 4 days. Each patient had one to five blood samples at different time points over 20 days. DOAC concentrations were determined using chromogenic assays. TG was investigated using ST-Genesia (STG-ThromboScreen, STG-DrugScreen).

RESULTS

 We included 215 patients (women 71.1%, mean age: 87 ± 4 years), 104 rivaroxaban and 111 apixaban, and 79.5% receiving reduced-dose regimen. We observed important inter-individual variabilities (coefficient of variation) whatever the regimen, at C _max [49-46%] and C _min [75-61%] in 15 mg rivaroxaban and 2.5 mg apixaban patients, respectively. The dose regimen was associated with C _max and C _min plasma concentrations in apixaban (p = 0.0058 and p = 0.0222, respectively), but not in rivaroxaban samples (multivariate analysis). Moreover, substantial variability of thrombin peak height (STG-ThromboScreen) was noticed at a given plasma concentration for both xabans, suggesting an impact of the underlying coagulation status on TG in elderly in-patients. After 6-month follow-up, major bleeding/thromboembolic event/death rates were 6.7%/1.0%/17.3% in rivaroxaban and 5.4%/3.6%/18.9% in apixaban patients, respectively.

CONCLUSION

 Our study provides original data in very elderly patients receiving DOAC in a real-life setting, showing great inter-individual variability in plasma concentrations and TG parameters. Further research is needed to understand the potential clinical impact of these findings.

Management of Massive Rivaroxaban Overdose With Acetaminophen and Isosorbide Mononitrate Overdose

Direct oral anticoagulants (DOACs) have been used more frequently for the prevention and management of thromboembolic disease in comparison to their predecessors. DOACs provide greater ease of administration, shorter half-lives, less monitoring, and fewer drug-drug interactions. With the rise of DOACs such as rivaroxaban, the opportunity for abuse also increases. Therefore, standardization of care based on rivaroxaban misuse must also be explored, an area in which there is not ample information. We present a case where a patient consumed a stockpile of her home medications in hopes to commit suicide. A 64-year-old female presented to the emergency department due to the ingestion of rivaroxaban 5,000 mg along with ingestion of acetaminophen 30,000 mg and isosorbide mononitrate 1000 mg in the setting of intentional self-harm with multiple declarations of being classified as Do Not Resuscitate. There have been documented cases of rivaroxaban overdose, however, there are no documented cases with levels of ingestion reaching 5,000 mg along with signs of severe bleeding. Our case study reviews the previously documented management of rivaroxaban abuse and the treatment that was given to our patient in the setting of extreme anticoagulant ingestion.

Effect of therapeutic versus prophylactic anticoagulation therapy on clinical outcomes in COVID-19 patients: a systematic review with an updated meta-analysis

BACKGROUND

Previous studies demonstrate a reduced risk of thrombosis and mortality with anticoagulant treatment in patients with COVID-19 than in those without anticoagulation treatment. However, an open question regarding the efficacy and safety of therapeutic anticoagulation (T-AC) versus a lower dose, prophylaxis anticoagulation (P-AC) in COVID-19 patients is still controversial.

METHODS

We systematically reviewed currently available randomized clinical trials (RCTs) and observational studies (OBs) from January 8, 2019, to January 8, 2022, and compared prophylactic and therapeutic anticoagulant treatment in COVID-19 patients. The primary outcomes were risk of mortality, major bleeding, and the secondary outcomes included venous and arterial thromboembolism. Subgroup analysis was also performed between critically ill and non-critically ill patients with COVID-19 and between patients with higher and lower levels of D-dimer. Sensitivity analysis was performed to decrease the bias and the impact of population heterogeneity.

RESULTS

We identified 11 RCTs and 17 OBs fulfilling our inclusion criteria. In the RCTs analyses, there was no statistically significant difference in the relative risk of mortality between COVID-19 patients with T-AC treatment and those treated with P-AC (RR 0.95, 95% CI, 0.78-1.15, P = 0.60). Similar results were also found in the OBs analyses (RR 1.21, 95% CI, 0.98-1.49, P = 0.08). The pooling meta-analysis using a random-effects model combined with effect sizes showed that in the RCTs and OBs analyses, patients with COVID-19 who received T-AC treatment had a significantly higher relative risk of the major bleeding event than those with P-AC treatment in COVID-19 patients (RCTs: RR 1.76, 95% CI, 1.19-2.62, P = 0.005; OBs: RR 2.39, 95% CI, 1.56-3.68, P < 0.0001). Compared with P-AC treatment in COVID-19 patients, patients with T-AC treatment significantly reduced the incidence of venous thromboembolism (RR 0.51, 95% CI, 0.39-0.67, P<0.00001), but it is not associated with arterial thrombosis events (RR 0.97, 95% CI, 0.66-1.42, P = 0.87). The subgroup analysis of OBs shows that the mortality risk significantly reduces in critically ill COVID-19 patients treated with T-AC compared with those with P-AC treatment (RR 0.58, 95% CI, 0.39-0.86, P = 0.007), while the mortality risk significantly increases in non-critically ill COVID-19 patients treated with T-AC (RR 1.56, 95% CI, 1.34-1.80, P < 0.00001). In addition, T-AC treatment does not reduce the risk of mortality in COVID-19 patients with high d-dimer levels in RCTs. Finally, the overall sensitivity analysis after excluding two RCTs studies remains consistent with the previous results.

CONCLUSIONS

In our integrated analysis of included RCTs and OBs, there is no significant difference between the mortality of T-AC and P-AC treatment in unselected patients with COVID-19. T-AC treatment in COVID-19 patients significantly reduced the incidence of venous thromboembolism but showed a higher risk of bleeding than those with P-AC treatment. In addition, P-AC treatment was superior to T-AC treatment in non-critically ill COVID-19 patients, the evidence supporting the necessity for T-AC treatment in critically ill COVID-19 patients came only from OBs.

TRIAL REGISTRATION

Protocol registration: The protocol was registered at PROSPERO (CRD42021293294).

Direct oral anticoagulants toxicity in children: an overview and practical guide

INTRODUCTION

By increasing use of direct oral anticoagulants (DOACs) in adults and children, gradual increase in the number of intentional or unintentional DOAC poisonings among children is suspected in the near future. Hence, clinicians and pharmacists need to be familiar with the clinical features and management of DOAC-toxicity among pediatric population.

AREAS COVERED

This article provides an overview and practical guide to DOAC-toxicity in pediatrics according to the available clinical evidence.

EXPERT OPINION

Based on limited available data, accidental pediatric ingestion of DOACs can be managed by supportive care in most cases. However, serious toxicity may occur following massive overdose, in presence of underlying disorders (renal or hepatic dysfunction) and concurrent anticoagulant therapy. Activated charcoal is recommended for known recent ingestion of DOACs (within 2-4 hours) to reduce the gastrointestinal absorption. Supportive interventions including local hemostatic measures and volume resuscitation are the cornerstone of management of bleeding. Vitamin K and fresh frozen plasma are ineffective for DOAC reversal and thus are not recommended. Currently, safety and efficacy data regarding the use of specific reversal agents (including idarucizumab and andexanet alfa) and 3-factor or 4-factor prothrombin complex concentrate (PCC) or activated PCC (aPCC) among children with DOAC-associated bleeding are lacking.

Rivaroxaban population pharmacokinetic and pharmacodynamic modeling in Iranian patients

WHAT IS KNOWN AND OBJECTIVE

Although predictable pharmacokinetic and pharmacodynamic of rivaroxaban allow fixed dosing regimens without routine coagulation monitoring, there is still the necessity to monitor and predict the effects of rivaroxaban in specific conditions and different populations. The current study was designed and conducted to analyze the rivaroxaban population pharmacokinetics in Iranian patients and establish a pharmacokinetic/pharmacodynamic model to predict the relationship between rivaroxaban concentration and its anticoagulant activity.

METHODS

A sequential nonlinear mixed effect pharmacokinetic/pharmacodynamic modeling method was used to establish the relation between rivaroxaban concentration and anti-factor Xa activity, prothrombin time, and activated partial thromboplastin time (aPTT) as pharmacodynamic biomarkers in a population of sixty-nine Iranian patients under treatment with oral rivaroxaban. Rivaroxaban plasma concentration was quantified by a validated high-performance liquid chromatography-tandem mass spectrometry.

RESULTS AND DISCUSSION

The typical population values (inter-individual variability%) of the oral volume of distribution and clearance for a one-compartment model were 61.2 L (21%) and 3.68 L·h^-1 (61%), respectively. Creatinine clearance and Child-Turcotte-Pugh score were found to affect the clearance. A direct link linear structural model best fitted the data for both prothrombin time and aPTT. The baseline estimates of aPTT and prothrombin time in the population were 35.0 (15%) and 12.6 (2%) seconds, respectively. The slope of the relationship between apTT, prothrombin time, and rivaroxaban concentration was 0.033 (28%) and 0.018 (54%) s·ml·ng^-1 , respectively. The selected model for anti-factor Xa activity consisted of a direct link inhibitory E_max model with Hill coefficient. The maximum level of inhibition (E_max ) was 4 IU·ml^-1 . The concentration of rivaroxaban producing 50% of the maximum inhibitory effect (EC₅₀ ) was 180 (24%) ng·ml^-1 , and Hill coefficient (γ) was 1.44 (108%). No covariates showed a statistically significant effect on PT and activated partial thromboplastin time prolonging properties and anti-factor Xa activity.

WHAT IS NEW AND CONCLUSION

Our results confirmed that pharmacokinetic/pharmacodynamic models similar to those of the other studies describe the relationship between the rivaroxaban concentration and its anticoagulant effect in Iranian patients. However, considerable differences were observed in the parameters of the pharmacodynamics-pharmacokinetic models with the results of other reports that can explain the unpredictable effects of rivaroxaban in some patients.

Biopharmaceutics considerations for direct oral anticoagulants

Vitamin K antagonists (VKA) and direct oral anticoagulants (DOACs) have been clinically used in the treatment of coagulation disorders. There are four DOACs approved since 2010 (dabigatran etexilate, rivaroxaban, apixaban, and edoxaban), and they were designed to overcome the practical limitations of VKA. This review summarized biopharmaceutics considerations about DOACs, which are critically discussed, applying risk analyses to subside the further classification of these drugs according to the Biopharmaceutics Classification System (BCS). These discussions included data compiled about physicochemical properties, equilibrium solubility, permeability, and drug dissolution of DOACs. From the biopharmaceutics characteristics is possible to identify critical variables related to the absorption process, which can help in the design of new formulations. The data were compared with the criteria recommended by regulatory agencies for the biopharmaceutics classification according to the BCS. From that, these data may be used to discuss the approval of generic medicines by the BCS-based biowaiver, and the clinical risks arising from novel formulations with DOACs. However, although there are indications of biopharmaceutics classifications for DOACs, conclusive information to classify these compounds according to the BCS is lacking, requiring more experimental studies to achieve this aim. Conclusive information is essential for a safe decision about the biowaiver, as well as to guide the development of new formulations containing the DOACs.

Prophylactic anticoagulation in sinus rhythm for stroke prevention in cardiovascular disease: contemporary meta-analysis of large randomized trials

AIMS

Anticoagulation with non-vitamin K oral anticoagulants (NOACs) to prevent stroke is a mainstay of atrial fibrillation (AF) management. However, multiple cardiovascular diseases (CVDs) are associated with elevated ischaemic stroke risk even in sinus rhythm. In this meta-analysis, we assess efficacy and safety of prophylactic NOAC agents for stroke prevention in patients without AF.

METHODS AND RESULTS

A search was conducted for randomized controlled trials (RCTs) that evaluated an NOAC and control drug (placebo or antiplatelet) in non-AF patients with mixed CVD. The primary efficacy and safety outcomes were ischaemic stroke and major bleeding, respectively. Results were stratified based on primary- and mini-NOAC doses. Thirteen RCTs were identified with a total of 89 383 patients with CVD in sinus rhythm (53 778 on NOAC, 35 605 on control drug; mean age 65.5 ± 2.7 years). Over a mean follow-up of 18.3 months, 1429 (1.6%) ischaemic strokes occurred. Use of NOAC was associated with 26% reduction in stroke [odds ratio (OR) 0.74, 95% confidence interval (CI) 0.62-0.87; 1.1 vs. 1.8 events per 100 person-years], with numbers needed to treat of 153 patients to prevent one stroke. Major bleeding was increased with NOAC (OR 1.74, 95% CI 1.44-2.09; 2.1 vs. 1.0 events per 100 person-years). The weighted net clinical benefit (wNCB, composite of ischaemic stroke and bleeding) did not suggest a favourable effect with any NOAC dose (wNCB for primary-dose: -0.35; mini-dose: -0.06).

CONCLUSION

Current evidence does not support use of NOACs for stroke prevention in non-AF CVD population as risk of major bleeding still exceeds ischaemic stroke benefit.

Anticoagulant Treatment Regimens in Patients with Covid-19: A Meta-Analysis

Coronavirus disease 2019 (COVID‐19) is associated with a hypercoagulable state. It has been hypothesized that higher‐dose anticoagulation, including therapeutic‐dose and intermediate‐dose anticoagulation, is superior to prophylactic‐dose anticoagulation in the treatment of COVID‐19. This meta‐analysis evaluated the efficacy and safety of higher‐dose anticoagulation compared with prophylactic‐dose anticoagulation in patients with COVID‐19. Ten randomized controlled open‐label trials with a total of 5,753 patients were included. The risk of death and net adverse clinical events (including death, thromboembolic events, and major bleeding) were similar between higher‐dose and prophylactic‐dose anticoagulation (risk ratio (RR) 0.96, 95% CI, 0.79–1.16, P = 0.66 and RR 0.87, 95% CI, 0.73–1.03, P = 0.11, respectively). Higher‐dose anticoagulation, compared with prophylactic‐dose anticoagulation, decreased the risk of thromboembolic events (RR 0.63, 95% CI, 0.47–0.84, P = 0.002) but increased the risk of major bleeding (RR 1.76, 95% CI, 1.19–2.62, P = 0.005). The risk of death showed no statistically significant difference between higher‐dose anticoagulation and prophylactic‐dose anticoagulation in noncritically ill patients (RR 0.87, 95% CI, 0.50–1.52, P = 0.62) and in critically ill patients with COVID‐19 (RR 1.04, 95% CI, 0.93–1.17, P = 0.5). The risk of death was similar between therapeutic‐dose vs. prophylactic‐dose anticoagulation (RR 0.92, 95% CI 0.69–1.21, P = 0.54) and between intermediate‐dose vs. prophylactic‐dose anticoagulation (RR 1.01, 95% CI 0.63–1.61, P = 0.98). In patients with markedly increased d‐dimer levels, higher‐dose anticoagulation was also not associated with a decreased risk of death as compared with prophylactic‐dose anticoagulation (RR 0.86, 95% CI, 0.64–1.16, P = 0.34). Without any clear evidence of survival benefit, these findings do not support the routine use of therapeutic‐dose or intermediate‐dose anticoagulation in critically or noncritically ill patients with COVID‐19.

Role of Direct Oral Anticoagulation Agents as Thromboprophylaxis in Antiphospholipid Syndrome

Antiphospholipid syndrome (APS) is an autoimmune disorder that causes venous, arterial and small-vessel thrombosis, pregnancy loss, and premature birth. Cardiac valvular disease, renal thrombotic microangiopathy, thrombocytopenia, hemolytic anemia, and cognitive impairment are some of its other clinical symptoms. Antiphospholipid antibodies cause endothelial cells, monocytes, and platelets to become activated, as well as an increase in tissue factor and thromboxane A2. Complement activation might play a key function in pathogenesis. Long-term oral anticoagulation is used to treat thrombosis, and individuals having arterial episodes should be treated quickly. Patients with systemic lupus erythematosus (SLE), as well as those with solely obstetric antiphospholipid syndrome, should get primary thromboprophylaxis. Obstetric care is based on a combination of medical and obstetric high-risk management, as well as aspirin and heparin therapy. Possible supplementary therapy for this condition is hydroxychloroquine. Statins, rituximab, and novel anticoagulant medicines are all potential future treatments for non-pregnant individuals with antiphospholipid syndrome. We aim to review the role of direct-acting oral anticoagulants (DOACs) as thromboprophylactic drugs in the treatment of APS in this article. The treatment of venous thromboembolism has been transformed by a new class of DOACs. These drugs, such as rivaroxaban, function by inhibiting factor Xa directly. Not only do they have known anticoagulant actions, but they also obviate the need for dosage monitoring and modification, in contrast to warfarin. We conducted an exhaustive literature search of PubMed/MEDLINE and Google Scholar Indexes using the keywords "Antiphospholipid syndrome," "thromboprophylaxis," and "oral anticoagulants" up to September 2021. We found that DOACs have been shown to be non-inferior to warfarin in a variety of anticoagulation situations in a number of high-powered clinical studies. In many hypercoagulable conditions such as APS, DOACs are quickly establishing themselves as first-line therapy. This article is focused on comprehensively reviewing the mechanism of action of DOACs, their role as thromboprophylactic drugs, risks and complications of DOACs, and comparing their efficacy with the standard treatment protocol and warfarin.

Conservative management of massive rivaroxaban overdose: A case report and literature review

In the cases of acute rivaroxaban overdose, conservative management without prothrombin complex concentrate or other coagulation factors may be sufficient if renal function is normal and there is no bleeding.

Bioequivalence and Food Effect Assessment of 2 Rivaroxaban Formulations in Healthy Chinese Volunteers: An Open, Randomized, Single-Dose, and 4-Period Crossover Study

Rivaroxaban is a direct factor Xa inhibitor used for the management of thromboembolic disorders. The aim of this study was to evaluate the safety, pharmacokinetic profile, and bioequivalence of a generic and a branded rivaroxaban formulation (Xarelto) under fasted and fed conditions in healthy Chinese volunteers. An open-label, randomized, single-dose, 4-period complete, and replicate crossover study in healthy Chinese volunteers was performed. A single oral dose of 20 mg of 2 rivaroxaban formulations was administered to 72 healthy volunteers, with 36 in the fasted group and 36 consuming a high-fat diet. The evaluated pharmacokinetic parameters, including maximum rivaroxaban concentration, the area under the concentration-time curve (AUC) from time 0 to the last measurable concentration, and AUC from time 0 to infinity, were assessed for BE. The plasma concentrations of rivaroxaban were measured by a validated liquid chromatography-tandem mass spectrometry method. The geometric mean ratios with 90% confidence intervals of the maximum rivaroxaban concentration, AUC from time 0 to the last measurable concentration, and AUC from time 0 to infinity were all within the range of 80% to 125% under fasted and fed conditions. The within-subject variability of the test and reference products was compared, and the upper limit of the 90% confidence intervals for the test-to-reference ratio of the within-subject variability was <2.5, which indicated that the rivaroxaban test and the rivaroxaban reference formulation were bioequivalent. No serious adverse events were reported during either fasted or fed conditions of the study.

Nonvalvular atrial fibrillation patients anticoagulated with rivaroxaban compared with warfarin exhibit reduced circulating extracellular vesicles with attenuated pro-inflammatory protein signatures

BACKGROUND

Rivaroxaban, a direct oral factor Xa inhibitor, mediates anti-inflammatory and cardiovascular-protective effects besides its well-established anticoagulant properties; however, these remain poorly characterized. Extracellular vesicles (EVs) are important circulating messengers regulating a myriad of biological and pathological processes and may be highly relevant to the pathophysiology of atrial fibrillation as they reflect alterations in platelet and endothelial biology. However, the effects of rivaroxaban on circulating pro-inflammatory EVs remain unknown.

OBJECTIVES

We hypothesized that rivaroxaban's anti-inflammatory properties are reflected upon differential molecular profiles of circulating EVs.

METHODS

Differences in circulating EV profiles were assessed using a combination of single vesicle analysis by Nanoparticle Tracking Analysis and flow cytometry, and proteomics.

RESULTS

We demonstrate, for the first time, that rivaroxaban-treated non-valvular atrial fibrillation (NVAF) patients (n=8) exhibit attenuated inflammation compared with matched warfarin controls (n=15). Circulating EV profiles were fundamentally altered. Moreover, quantitative proteomic analysis of enriched plasma EVs from six pooled biological donors per treatment group revealed a profound decrease in highly pro-inflammatory protein expression and complement factors, together with increased expression of negative regulators of inflammatory pathways. Crucially, a reduction in circulating levels of soluble P-selectin was observed in rivaroxaban-treated patients (compared with warfarin controls), which negatively correlated with the patient's time on treatment.

CONCLUSION

Collectively, these data demonstrate that NVAF patients anticoagulated with rivaroxaban (compared with warfarin) exhibit both a reduced pro-inflammatory state and evidence of reduced endothelial activation. These findings are of translational relevance toward characterizing the anti-inflammatory and cardiovascular-protective mechanisms associated with rivaroxaban therapy.

Physiologically Based Pharmacokinetic Modelling to Identify Pharmacokinetic Parameters Driving Drug Exposure Changes in the Elderly

BACKGROUND

Medication use is highly prevalent with advanced age, but clinical studies are rarely conducted in the elderly, leading to limited knowledge regarding age-related pharmacokinetic changes.

OBJECTIVE

The objective of this study was to investigate which pharmacokinetic parameters determine drug exposure changes in the elderly by conducting virtual clinical trials for ten drugs (midazolam, metoprolol, lisinopril, amlodipine, rivaroxaban, repaglinide, atorvastatin, rosuvastatin, clarithromycin and rifampicin) using our physiologically based pharmacokinetic (PBPK) framework.

METHODS

PBPK models for all ten drugs were developed in young adults (20-50 years) following the best practice approach, before predicting pharmacokinetics in the elderly (≥ 65 years) without any modification of drug parameters. A descriptive relationship between age and each investigated pharmacokinetic parameter (peak concentration [C_max], time to C_max [t_max], area under the curve [AUC], clearance, volume of distribution, elimination-half-life) was derived using the final PBPK models, and verified with independent clinically observed data from 52 drugs.

RESULTS

The age-related changes in drug exposure were successfully simulated for all ten drugs. Pharmacokinetic parameters were predicted within 1.25-fold (70%), 1.5-fold (86%) and 2-fold (100%) of clinical data. AUC increased progressively by 0.9% per year throughout adulthood from the age of 20 years, which was explained by decreased clearance, while C_max, t_max and volume of distribution were not affected by human aging. Additional clinical data of 52 drugs were contained within the estimated variability of the established age-dependent correlations for each pharmacokinetic parameter.

CONCLUSION

The progressive decrease in hepatic and renal blood flow, as well as glomerular filtration, rate led to a reduced clearance driving exposure changes in the healthy elderly, independent of the drug.

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

BACKGROUND

Non-vitamin K antagonist oral anticoagulants (NOACs) have been widely used for stroke prevention in atrial fibrillation (AF) and the treatment and prevention of venous thromboembolism. There is an issue with safety, especially in clinically relevant bleeding. We performed a network meta-analysis to evaluate the risk of major gastrointestinal (GI) bleeding associated with NOACs.

METHODS

Interventions were warfarin, enoxaparin, apixaban, dabigatran, edoxaban, and rivaroxaban. The primary outcome was the incidence of major GI bleeding. A subgroup analysis was performed according to the following indications: AF, deep venous thrombosis/pulmonary embolism, and postsurgical prophylaxis.

RESULTS

A total of 29 randomized controlled trials (RCTs) and 4 large observation population studies were included. Compared with warfarin, apixaban showed a decreased the risk of major GI bleeding (relative risk [RR] 0.54, 95% confidence interval [CI] 0.25-0.76), and rivaroxaban tended to increase this risk (RR 1.40, 95% CI 1.06-1.85). Dabigatran (RR 1.25, 95% CI 0.98-1.60), edoxaban (RR 1.07, 95% CI 0.69-1.65), and enoxaparin (RR 1.24, 95% CI 0.63-2.43) did not significantly increase the risk of GI bleeding than did warfarin. In the subgroup analysis, according to indications, apixaban showed a decreased risk of major GI bleeding (RR 0.50, 95% CI 0.34-0.74) than did warfarin in AF studies. Dabigatran (RR 2.36, 95% CI 1.55-3.60, and rivaroxaban (RR 1.75, 95% CI 1.10-6.41) increased the risk of major GI bleeding than did apixaban. An analysis of studies on venous thromboembolism or pulmonary embolism showed that no individual NOAC or enoxaparin was associated with an increased risk of major GI bleeding compared to warfarin.

CONCLUSION

Individual NOACs had varying profiles of GI bleeding risk. Results of analyses including only RCTs and those including both RCTs and population studies showed similar trends, but also showed several differences.

Direct oral anticoagulants (DOACs) and neck of femur fractures: Standardising the perioperative management and time to surgery

Demographic projections for hip fragility fractures indicate a rising annual incidence by virtue of a multimorbid, ageing population with more noncommunicable diseases (NCDs). NCDs are characterised by slow progression and long duration ranging from ischaemic cardiovascular disease, cerebrovascular disease, diabetes, chronic obstructive pulmonary disease to various cancers. Management of this disease burden often involves commencing patients on oral anticoagulants to reduce the risk of thromboembolic events. The use of direct oral anticoagulants (DOACs) in clinical practice has increased due to their rapid onset of action, short half-life and predictable anticoagulant effects, without the need for routine monitoring. Safe and timely surgical intervention relies on reversal of anticoagulants. However, the lack of specific evidence-based guidelines for the perioperative management of patients on DOACs with hip fractures has proved challenging; in particular, the accessibility of DOAC-specific assays, justification of the cost-benefit ratio of targeted reversal agents and indications for neuraxial anaesthesia. This has led to potentially avoidable delays in surgical intervention. Following a literature review of the pharmacokinetic and pharmacodynamics of commonly used DOACs in our region including the role of surrogate markers, we propose a systematic, evidence-based guideline to the perioperative management of hip fractures DOACs. We believe this standardised protocol can be easily replicated between hospitals. We recommend that if patients are deemed suitable for a general anaesthesia, with satisfactory renal function, optimal surgical time should be 24 h following the last ingested dose of DOAC.

Use of oral rivaroxaban in cerebral venous thrombosis

Background

Cerebral venous thrombosis (CVT) is an uncommon cause of stroke in humans and the mainstay of treatment is anticoagulation unless contraindicated. Non-vitamin K oral anticoagulants have not been duly evaluated in randomized controlled trials in CVT.

Objective

To compare the efficacy and safety of oral rivaroxaban with vitamin K anticoagulant (warfarin) in preventing recurrent venous thromboembolism (VTE) in patients with CVT.

Methods

Adult patients with CVT, who were stable after 5-12 days of treatment with parenteral heparin 1 mg/kg, were screened for eligibility. The patients were randomly divided into two groups to receive oral rivaroxaban 20-30 mg daily or warfarin 1, 3 or 5 mg daily (with the dose adjusted to maintain an INR of 2-3), for 3-12 months. Recanalization rates, periprocedural complications, and clinical outcomes were assessed by Magnetic Resonance Venography (MRV) and National Institutes of Health Stroke Scale (NIHSS) at 3rd, 6th and 12th month follow-ups.

Results

In total, 45 patients with CVT were randomized to the two treatment groups (21 to rivaroxaban and 24 to warfarin). Overall recanalization was achieved by 18 (86%) and 20 (83%) cases from rivaroxaban and warfarin group, respectively at 6th month follow-up; and by all 45 (100%) cases from the both groups at 12th month follow-up. Excellent outcome (NIHSS score 0) was obtained by 20 (95%) cases from rivaroxaban group at 3rd to 12th month follow-ups; and by 23 (96%) cases at 6th to 12th month follow-ups. There were no major bleeding events during the trial. None of the patients developed recurrence of thrombosis. Statistically, no significant difference between the two treatment groups in terms of recanalization and clinical outcomes could be observed.

Conclusion

Rivaroxaban is a safe option in CVT however; larger randomized controlled studies will impact the results validity.

Persistent Rivaroxaban Effect Due to Impaired Renal Clearance and Medication Effects

Rivaroxaban (Xarelto; Johnson & Johnson Services, Inc) is a direct oral anticoagulant (DOAC) that works by directly inhibiting the active site of factor Xa (FXa). Rivaroxaban is metabolized and cleared via the kidney and liver. The results of various studies have shown that patients with severe renal impairment should receive reduced dosages of rivaroxaban or another anticoagulant due to impaired clearance. Although it is not required, monitoring rivaroxaban is useful in some conditions; however, the assays required for such monitoring are not readily available. Herein, we present a case of a 68-year-old Caucasian male patient who was receiving rivaroxaban (20 mg/day) for atrial flutter and had mild renal impairment. The patient was found to have increased effect of rivaroxaban due to further impairment of renal clearance caused by several renally cleared medications. This case highlights the importance of closely examining the renal function of and medication list for a patient before starting DOACs such as rivaroxaban.

A meta-analysis on anticoagulation after vascular trauma

Purpose

There is much debate regarding the use of anticoagulation following vascular trauma. The aim of this meta-analysis was to compare the outcome of trauma following administration of anticoagulation medication.

Methods

The literature search was carried out using Ovid MEDLINE and PubMed databases to search for keywords and MeSH terms including “Anticoagulation”, “Vascular Surgery”, “Vascular Trauma”, “Vascular Repair”, “Repair” and “Wounds and Injuries”.

Results

Use of anticoagulation was associated with a better prognosis for overall vascular trauma outcomes (weighted OR 0.46; 95% CI 0.34–0.64; P < 0.00001), as well as reduced risk of amputation for both lower and upper limb vascular trauma (weighted OR 0.42; 95% CI 0.22–0.78; P = 0.007), and reduced occurrence of reoperation events and amputations in isolated lower limb vascular trauma (weighted OR 0.27; 95% CI 0.14–0.52; P < 0.0001).

Conclusion

There was a statistically significant correlation between the use of anticoagulation and vascular trauma outcome. A major limitation with many of the studies includes a lack of prospective analysis and therefore we recommend prospective studies to properly elucidate prognostic outcomes following use of these anticoagulants. Further studies need to be conducted to assess the effects of timing of anticoagulant delivery, dosages and severity of traumatic injury. Thus, this would prove to be very useful in the formation of guidelines.

The 2018 European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation

The current manuscript is the second update of the original Practical Guide, published in 2013 [Heidbuchel et al. European Heart Rhythm Association Practical Guide on the use of new oral anticoagulants in patients with non-valvular atrial fibrillation. Europace 2013;15:625-651; Heidbuchel et al. Updated European Heart Rhythm Association Practical Guide on the use of non-vitamin K antagonist anticoagulants in patients with non-valvular atrial fibrillation. Europace 2015;17:1467-1507]. Non-vitamin K antagonist oral anticoagulants (NOACs) are an alternative for vitamin K antagonists (VKAs) to prevent stroke in patients with atrial fibrillation (AF) and have emerged as the preferred choice, particularly in patients newly started on anticoagulation. Both physicians and patients are becoming more accustomed to the use of these drugs in clinical practice. However, many unresolved questions on how to optimally use these agents in specific clinical situations remain. The European Heart Rhythm Association (EHRA) set out to coordinate a unified way of informing physicians on the use of the different NOACs. A writing group identified 20 topics of concrete clinical scenarios for which practical answers were formulated, based on available evidence. The 20 topics are as follows i.e., (1) Eligibility for NOACs; (2) Practical start-up and follow-up scheme for patients on NOACs; (3) Ensuring adherence to prescribed oral anticoagulant intake; (4) Switching between anticoagulant regimens; (5) Pharmacokinetics and drug-drug interactions of NOACs; (6) NOACs in patients with chronic kidney or advanced liver disease; (7) How to measure the anticoagulant effect of NOACs; (8) NOAC plasma level measurement: rare indications, precautions, and potential pitfalls; (9) How to deal with dosing errors; (10) What to do if there is a (suspected) overdose without bleeding, or a clotting test is indicating a potential risk of bleeding; (11) Management of bleeding under NOAC therapy; (12) Patients undergoing a planned invasive procedure, surgery or ablation; (13) Patients requiring an urgent surgical intervention; (14) Patients with AF and coronary artery disease; (15) Avoiding confusion with NOAC dosing across indications; (16) Cardioversion in a NOAC-treated patient; (17) AF patients presenting with acute stroke while on NOACs; (18) NOACs in special situations; (19) Anticoagulation in AF patients with a malignancy; and (20) Optimizing dose adjustments of VKA. Additional information and downloads of the text and anticoagulation cards in different languages can be found on an EHRA website (www.NOACforAF.eu).

Psychometric validation of anti-clot treatment scale and treatment satisfaction questionnaire for medication version II in Japanese patients with atrial fibrillation

Aims: The Anti-Clot Treatment Scale (ACTS) and Treatment Satisfaction Questionnaire for Medication version II (TSQM-II) are validated treatment satisfaction patient-reported outcome (PRO) instruments. The ACTS includes two domains: Burdens and Benefits; the TSQM-II includes four: Effectiveness, Side Effects, Convenience, and Global Satisfaction. Japanese-language versions of the ACTS and TSQM-II have been developed and linguistically validated. This study aimed to assess their psychometric properties in Japanese patients with atrial fibrillation (AF). Materials and methods: ACTS and TSQM-II data from 534 patients with AF were collected in a Japanese post-marketing surveillance study of a direct oral-anticoagulant, rivaroxaban. Four key psychometric properties, in line with best practice guidelines from the US Food and Drug Administration, were examined using traditional psychometric methods: acceptability, scaling assumptions, reliability (i.e. internal consistency reliability, test-retest reliability), and construct validity (i.e. convergent validity and known groups). Results: ACTS Burdens and Benefits and TSQM-II Effectiveness, Convenience, and Global Satisfaction scales were found to be acceptable (e.g. item-level missing data at baseline <4%), with all scales having good internal consistency (Cronbach's alpha > 0.80). test-retest reproducibility intraclass correlation coefficients for the ACTS Burdens and Benefits were 0.59 and 0.65, respectively, and between 0.54-0.61 for the TSQM-II scales. Known-groups validity for the ACTS and TSQM-II was supported by differences in scale scores by positive and negative impact (p < 0.05). Correlations between the ACTS and TSQM-II (convergent validity) were lower than expected (range r = 0.09-0.48), but in line with the original ACTS development study. Limitations: Evaluation of test-retest reproducibility was limited by assessment period, which was longer (3 months) than recommended guidelines (usually up to 2 weeks). Conclusions: Overall, Japanese versions of ACTS and TSQM-II scales satisfied internal consistency reliability and traditional validity criteria. Our study supports the ACTS and TSQM-II as appropriate PRO instruments to measure satisfaction with anticoagulant treatment in Japanese patients with AF. Trial registration: NCT01598051, clinicaltrials.gov; registered April 20, 2012.

Reversal of direct oral anticoagulants: Guidance from the Anticoagulation Forum

Two specific reversal agents for direct oral anticoagulants (DOACs) have been approved in the United States: idarucizumab for dabigatran reversal and andexanet alfa for apixaban and rivaroxaban reversal. Non-specific prohemostatic agents such as prothrombin complex concentrate (PCC) and activated PCC have also been used for DOAC reversal. The goal of this document is to provide comprehensive guidance from the Anticoagulation Forum, a North American organization of anticoagulation providers, regarding use of DOAC reversal agents. We discuss indications for reversal, provide guidance on how the individual reversal agents should be administered, and offer suggestions for stewardship at the health system level.

Efficacy of low-dose rivaroxaban in an 88-year-old female with pulmonary embolism: A case report

RATIONALE

Rivaroxaban has numerous advantages over traditional anticoagulation therapy. Fixed doses can be administered without requiring routine monitoring of coagulation, and anticoagulation efficacy is more predictable. Safety, including fewer drug interactions, and reduced bleeding, is also improved with rivaroxaban based on current recommendations. The goal of this report was to explore if low-dose rivaroxaban 10 mg once daily was effective in an elderly patient who developed minor bleeding when treated with rivaroxaban (10 mg twice daily) for a pulmonary embolism.

PATIENT CONCERNS

We present an 88-year-old female with dyspnea and fatigue, which became increasingly worse over a month in the absence of medication. Her weight was 64 kg. Routine coagulation assays and renal function were normal at time of admission.

DIAGNOSIS

Deep vein thrombosis and pulmonary embolism were confirmed by venous compression ultrasonography and computed tomography pulmonary angiography.

INTERVENTIONS

Oral rivaroxaban 10 mg twice daily was administered, but the patient developed hemoptysis and gum bleeding 5 days later. The dose of rivaroxaban was reduced to 10 mg once daily, and bleeding gradually disappeared after 3 days.

OUTCOME

At follow-up 90 days after treatment, the patient reported no discomfort. Venous compression ultrasonography and computed tomography pulmonary angiography showed normal results; therefore, treatment was terminated.

LESSONS

Elderly patients exhibit variable tolerance of anticoagulants, warranting careful consideration of the risk of bleeding. Low-dose rivaroxaban was an effective treatment for pulmonary embolism in the elderly patient presented here.

Perioperative Considerations in the Management of Anticoagulation Therapy for Patients Undergoing Surgery

PURPOSE OF REVIEW

As ambulatory surgery has become increasingly more common, the appropriate management of anticoagulation therapy in patients undergoing invasive procedures has become progressively more relevant to healthcare professionals. The purpose of this literature review is to provide an overview of current common anaticoagulants and their pharmacological properties and to evaluate recent relevant literature and bridging therapy and provide recommendations on risk-guided therapy.

RECENT FINDINGS

With the development of new drugs and the advancing study and practice of anticoagulation use, clinicians must keep up-to-date on the optimal management of patients requiring anticoagulation. NOACs and warfarin continue to be the mainstays of treatment, with varying timelines regarding when to hold administration of the different agents within the perioperative period. There are numerous factors that are considered in patients with multiple comorbidities including the risk for stroke on long-term anticoagulation and risk for thromboembolism, particularly in the perioperative setting when certain medication regimens may be altered and/or briefly held. There is ongoing investigation whether certain NOACs have more efficacy or greater safety profiles, depending on the degree of surgical intervention.

Adverse reaction profiles of hemorrhagic adverse reactions caused by direct oral anticoagulants analyzed using the Food and Drug Administration Adverse Event Reporting System (FAERS) database and the Japanese Adverse Drug Event Report (JADER) database

Direct oral anticoagulants (DOACs) are used in anticoagulant therapy. The purpose of this study was to evaluate the association of DOAC-induced gastrointestinal (GI) and nervous system hemorrhage using the FDA's Adverse Event Reporting System (FAERS) database and the Japanese Adverse Drug Event Report (JADER) database. We identified and analyzed the reports of hemorrhagic reactions between 2004 and 2016 from the FAERS and JADER databases, and calculated the adjusted reported odds ratio (ROR) using the multiple logistic regression method. Additionally, we used the time-to-onset analysis. In the FAERS database, the adjusted ROR of apixaban, rivaroxaban, and dabigatran for GI hemorrhage was 6.79 (5.84-7.91), 19.58 (18.85-20.34), and 14.51 (13.58-15.51), respectively. In the JADER database, the adjusted ROR of apixaban, rivaroxaban, edoxaban, and dabigatran for GI hemorrhage was 11.80 (9.50-14.64), 11.03 (9.18-13.26), 10.17 (6.95-14.88), and 9.85 (7.23-13.42), respectively. We found that the association of GI hemorrhage with DOACs was affected by sex (female). Additionally, 30% of GI hemorrhage was observed after 30 days. Hemorrhagic reactions of both GI and nervous systems were observed in both the spontaneous reporting system databases. We recommend that female patients who experience symptoms related to GI hemorrhage should be closely monitored and advised to adhere to an appropriate care plan. Additionally, our results show that patients should be closely monitored for hemorrhage even after a month.

Patient-reported treatment satisfaction with rivaroxaban in Japanese non-valvular atrial fibrillation patients: an observational study

OBJECTIVES

Rivaroxaban has previously been shown to be as efficacious and safe as warfarin for the prevention of stroke in non-valvular atrial fibrillation (NVAF). Therefore, treatment satisfaction becomes an important consideration. Here we examine treatment satisfaction in Japanese NVAF patients who were switched from warfarin to rivaroxaban.

METHODS

Patient-reported outcome (PRO) data were collected as part of a prospective, multi-center, post-marketing surveillance (PMS) of a direct oral-anticoagulant, rivaroxaban, in Japan. The Anti-Clot Treatment Scale (ACTS) and the Treatment Satisfaction Questionnaire for Medication version II (TSQM-II) were collected at baseline, month 3, and month 6. Change in scores from baseline to month 3 and month 6 were assessed. Exploratory analyses included change in scores by patient characteristics. Safety and effectiveness of rivaroxaban were also assessed.

RESULTS

ACTS Burdens scores significantly improved at month 3 (54.6 ± 6.3) and month 6 (54.5 ± 6.5) compared to baseline (51.0 ± 7.6) (p < .001). ACTS Benefits score remained stable over time (baseline = 10.1 ± 2.8, month 3 = 10.2 ± 3.1, month 6 = 10.1 ± 3.1). Mean TSQM-II sub-scale scores significantly improved at month 3 and month 6 compared to baseline for all four domains (all p < .001).

CONCLUSIONS

Findings suggest treatment satisfaction may improve in Japanese NVAF patients after a switch from warfarin to rivaroxaban. Higher treatment satisfaction may translate into improved treatment adherence, which is critical for the long-term prevention of stroke.

Factors That Determine the Prothrombin Time in Patients With Atrial Fibrillation Receiving Rivaroxaban

Rivaroxaban, a direct factor Xa inhibitor, is widely used to reduce the chance of stroke in patients with atrial fibrillation (AF). It is not clear why the prothrombin time (PT) of the international normalized ratio (INR) fails to correlate with treatment using rivaroxaban in patients with AF. In this study, patient characteristics, the rivaroxaban dosage, AF type, drug history, biochemical properties, and hematological profiles were assessed in patients treated with rivaroxaban. In 69 patients with AF receiving rivaroxaban, 27 (39.1%) patients had a normal INR (≤1.1, group 1), 27 (39.1%) patients had a slightly prolonged INR (1.1∼1.5, group 2), and 15 (21.7%) patients had a significantly prolonged INR (>1.5, group 3). Group 1 patients had a higher incidence of a stroke history than did patients in group 2 (P = .026) and group 3 (P = .032). We scored patients with a persistent AF pattern (1 point), paroxysmal AF pattern (0 point), renal function (ie, the creatinine clearance rate in mL/min/1.73 m² of >60 as 0 points, of 30∼60 as 1 point, and of <30 as 2 points), and no history of stroke (1 point), and we found that group 3 had a higher score than groups 2 or 1 (2.9 ± 0.8, 2.4 ± 0.7, and 2 ± 0.7, respectively; P < .05). There were similar incidences of bleeding, stroke, and unexpected hospitalizations among the 3 groups. The PT of the INR is determined by multiple variables in patients with AF receiving rivaroxaban. Rivaroxaban-treated patients with AF having different INR values may have similar clinical outcomes.

Pharmacokinetic drug interactions of the non-vitamin K antagonist oral anticoagulants (NOACs)

The use of warfarin, the most commonly prescribed oral anticoagulant, is being questioned by clinicians worldwide due to warfarin several limitations (a limited therapeutic window and significant variability in dose-response among individuals, in addition to a potential for drug-drug interactions). Therefore, the need for non-vitamin K antagonist oral anticoagulants (NOACs) with a rapid onset of antithrombotic effects and a predictable pharmacokinetic (PK) and pharmacodynamic (PD) profile led to the approval of five new drugs: the direct factor Xa (F-Xa) inhibitors rivaroxaban, apixaban, edoxaban and betrixaban (newly approved by FDA) and the direct thrombin (factor-IIa) inhibitor dabigatran etexilate. The advantages of NOACs over warfarin are a fixed-dosage, the absence of the need for drug monitoring for changes in anti-coagulation and fewer clinically significant PK and PD drug-drug interactions. NOACs exposure will likely be increased by the administration of strong P-glycoprotein (P-gp) and cytochrome P450 (CYP) 3A4-inhibitors and may increase the risk of bleeds. On the contrary, P-gp inducers could significantly decrease the NOACs plasma concentration with an associated reduction in their anticoagulant effects. This manuscript gives an overview of NOACs PK profiles and their drug-drug interactions potential. This is meant to be of help to physicians in choosing the best therapeutic approach for their patients.

Practical guidance on the use of laboratory testing in the management of bleeding in patients receiving direct oral anticoagulants

Direct oral anticoagulants (DOACs) have demonstrated a favorable benefit–risk profile in several thromboembolic disorders and are increasingly used in routine clinical practice. A number of real-world studies on DOACs are ongoing, and data published so far have shown broadly similar outcomes to those demonstrated in the respective phase III trials. Despite their beneficial attributes, bleeding risk (as with any other anticoagulants) is often a concern for physicians when prescribing DOACs, particularly in elderly patients, those with significant comorbidities, and other high-risk patient populations. Although the absence of routine coagulation monitoring is an advantage of the DOACs, measuring their anticoagulant effect and/or plasma drug levels may be helpful in certain clinical scenarios to help patient management and improve outcomes. In this paper, practical guidance and recommendations are provided for clinical situations in which the test results may aid clinical decision-making, including patients with life-threatening bleeding events, patients without bleeding but with test results indicating a risk of bleeding, for those patients with a suspected thromboembolism while receiving a DOAC, or prior to patients undergoing elective or urgent surgical procedures. Finally, appropriate monitoring of the DOACs could be of substantial benefit to patients, and there is a high potential for development in this area in the future.

Management consensus guidance for the use of rivaroxaban – an oral, direct factor Xa inhibitor

A number of novel oral anticoagulants that directly target factor Xa or thrombin have been developed in recent years. Rivaroxaban and apixaban (direct factor Xa inhibitors) and dabigatran etexilate (a direct thrombin inhibitor) have shown considerable promise in large-scale, randomised clinical studies for the management of thromboembolic disorders, and have been approved for clinical use in specific indications. Rivaroxaban is licensed for the prevention of venous thromboembolism in patients undergoing elective hip or knee replacement surgery, the treatment of deep-vein thrombosis and prevention of recurrent venous thromboembolism, and for stroke prevention in patients with non-valvular atrial fibrillation. Based on the clinical trial data for rivaroxaban, feedback on its use in clinical practice and the authors’ experience with the use of rivaroxaban, practical guidance for the use of rivaroxaban in special patient populations and specific clinical situations is provided. Although most recommendations are in line with the European summary of product characteristics for the approved indications, additional and, in several areas, different recommendations are given based on review of the literature and the authors’ clinical experience.

Dissociation between the pharmacokinetics and pharmacodynamics of once-daily rivaroxaban and twice-daily apixaban: a randomized crossover study

Essentials In this crossover study the anticoagulant effects of rivaroxaban and apixaban were compared. Healthy volunteers received rivaroxaban 20 mg once daily or apixaban 5 mg twice daily. Rivaroxaban was associated with more prolonged inhibition of thrombin generation than apixaban. Rivaroxaban induced a clear prolongation of prothrombin time and activated partial thromboplastin time.

SUMMARY

Background The anticoagulant actions of the oral direct activated factor Xa inhibitors, rivaroxaban and apixaban, have not previously been directly compared. Objectives To compare directly the steady-state pharmacokinetics and anticoagulant effects of rivaroxaban and apixaban at doses approved for stroke prevention in patients with non-valvular atrial fibrillation. Methods Twenty-four healthy Caucasian male volunteers were included in this open-label, two-period crossover, phase 1 study (EudraCT number: 2015-002612-32). Volunteers were randomized to receive rivaroxaban 20 mg once daily or apixaban 5 mg twice daily for 7 days, followed by a washout period of at least 7 days before they received the other treatment. Plasma concentrations and anticoagulant effects were measured at steady state and after drug discontinuation. Results Overall exposure was similar for both drugs: the geometric mean area under the plasma concentration-time curve for the 0-24-h interval was 1830 μg h L-1 for rivaroxaban and 1860 μg h L-1 for apixaban. Rivaroxaban was associated with greater inhibition of endogenous thrombin potential (geometric mean area under the curve relative to baseline during the 0-24-h interval: 15.5 h versus 17.5 h) and a more pronounced maximal prolongation relative to baseline of prothrombin time (PT) (1.66-fold versus 1.14-fold) and activated partial thromboplastin time (APTT) (1.43-fold versus 1.16-fold) at steady state than apixaban. Conclusions Despite similar exposure to both drugs, rivaroxaban 20 mg once daily was associated with greater and more sustained inhibition of thrombin generation than apixaban 5 mg twice daily. Sensitive PT and APTT assays can be used to estimate the anticoagulant effects of rivaroxaban.

Once- versus twice-daily direct oral anticoagulants in non-valvular atrial fibrillation

INTRODUCTION

Direct oral anticoagulants (DOACs) have emerged as alternatives to vitamin K antagonists for the prevention of stroke in patients with non-valvular atrial fibrillation (NVAF). Four DOACs: dabigatran, rivaroxaban, apixaban and edoxaban, are currently available. In the absence of head-to-head clinical comparisons of DOACs, dosing regimen may influence drug choice. Areas covered: Edoxaban and rivaroxaban are administered once daily, dabigatran and apixaban twice daily. The selection of these dosage regimens is largely based on studies for the prevention or treatment of venous thromboembolism or acute coronary syndrome. Edoxaban is the only DOAC in which once and twice-daily regimens were compared in patients with NVAF; bleeding rates were higher in the twice-daily groups. Once-daily versus twice-daily regimens have a number of practical implications. Missing a once-daily dose would have a greater impact on anticoagulation. Some real world and retrospective studies found that a once-daily dosing regimen leads to better adherence and persistence to therapy, an important consideration for maintaining optimum anticoagulation. However, other studies have not found increased adherence among once daily regimens. Expert opinion: Prescription of DOACs should be tailored to the individual patient and dosing regimen is only one of the variables that should be taken into account.

Novel Anticoagulant Agents in the Perioperative Setting

An increasing number of oral anticoagulants have become available over the past decade. Each of these agents has differing implications on both regional and neuraxial anesthetic techniques. This article describes the pharmacology, pharmacokinetics, and pharmacodynamics of the most commonly used novel oral anticoagulants (NOACs). It also outlines recent guidelines for the use of NOACs in the perioperative setting, especially with regard to neuraxial anesthesia.

Gastrointestinal bleeding in patients on novel oral anticoagulants: Risk, prevention and management

Novel oral anticoagulants (NOACs), which include direct thrombin inhibitor (dabigatran) and direct factor Xa inhibitors (rivaroxaban, apixaban and edoxaban), are gaining popularity in the prevention of embolic stroke in non-valvular atrial fibrillation as well as in the prevention and treatment of venous thromboembolism. However, similar to traditional anticoagulants, NOACs have the side effects of bleeding, including gastrointestinal bleeding (GIB). Results from both randomized clinical trials and observations studies suggest that high-dose dabigatran (150 mg b.i.d), rivaroxaban and high-dose edoxaban (60 mg daily) are associated with a higher risk of GIB compared with warfarin. Other risk factors of NOAC-related GIB include concomitant use of ulcerogenic agents, older age, renal impairment, Helicobacter pylori infection and a past history of GIB. Prevention of NOAC-related GIB includes proper patient selection, using a lower dose of certain NOACs and in patients with renal impairment, correction of modifiable risk factors, and prescription of gastroprotective agents. Overt GIB can be managed by withholding NOACs followed by delayed endoscopic treatment. In severe bleeding, additional measures include administration of activated charcoal, use of specific reversal agents such as idarucizumab for dabigatran and andexanent alfa for factor Xa inhibitors, and urgent endoscopic management.

Primary and key secondary results from the ROCKET AF trial, and their implications on clinical practice

BACKGROUND

The safety and efficacy of the oral anticoagulant rivaroxaban were studied in the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF trial). A number of subanalyses of the ROCKET AF trial have subsequently analyzed the use of rivaroxaban in special patient populations.

METHODS

The outcomes of the ROCKET AF trial were reviewed. The use of rivaroxaban in higher risk populations, as determined by the presence of co-morbidities included in the CHADS2 criteria, was analyzed. Requirements for dose adjustment in patients with renal impairment and in East Asian patients were described. Finally, clinical management challenges, including interruptions in therapy, drug discontinuation, management of bleeding events, drug interactions, and management of patients requiring cardioversion/ablation were reviewed.

RESULTS

Rivaroxaban is efficacious in high-risk populations, including elderly patients, patients with diabetes, heart failure, history of stroke, prior myocardial infarction, or peripheral arterial disease (PAD). Patients with PAD have a higher risk of bleeding with rivaroxaban compared with warfarin. East Asian populations do not require a dose adjustment for rivaroxaban, while a reduced dose of 15 mg daily is required for patients with moderate renal impairment. Rivaroxaban remains effective with temporary interruptions in therapy and in patients requiring cardioversion/ablation. Rates of major bleeding and subsequent outcomes were similar in patients on warfarin and rivaroxaban, although rates of gastrointestinal bleeding were higher with rivaroxaban. Concurrent use of antiarrhythmic therapy was not associated with adverse outcomes.

CONCLUSIONS

Rivaroxaban represents an efficacious alternative to warfarin in high-risk patients with AF. Dose adjustment is required for patients with moderate renal impairment. Rivaroxaban can be used safely in a number of challenging clinical management scenarios although the concurrent use of amiodarone requires more study.

Use of rivaroxaban in patients with stroke

Rivaroxaban, an inhibitor of Factor Xa, is a direct oral anti-coagulant that has been found to be non-inferior to warfarin in preventing cerebral ischemia in patients with non-valvular atrial fibrillation and in the subgroup of patients with a history of the previous stroke or transient ischemic attack. Vascular neurologists in daily clinical practice may encounter patients taking rivaroxaban or patients who may benefit from its use. In this paper, we review the current clinical indications, contraindications, and clinical management guidelines for rivaroxaban while providing a special focus on neurological aspects and expert opinions on rivaroxaban therapy management in various situations that a neurologist may encounter when treating patients with an ischemic stroke (including those requiring intravenous or intra-arterial reperfusion therapy) and patients with an intracerebral hemorrhage. Since data from clinical trials and real-life data are missing in some clinical situations, strong recommendations are not always available. Nevertheless, practical guidelines should be adopted to maximize benefits from this oral anti-coagulant.