Optimizing quality care for the oral vitamin K antagonists (VKAs)

Synergy of Mutation-Induced Effects in Human Vitamin K Epoxide Reductase: Perspectives and Challenges for Allo-Network Modulator Design

The human Vitamin K Epoxide Reductase Complex (hVKORC1), a key enzyme transforming vitamin K into the form necessary for blood clotting, requires for its activation the reducing equivalents delivered by its redox partner through thiol-disulfide exchange reactions. The luminal loop (L-loop) is the principal mediator of hVKORC1 activation, and it is a region frequently harbouring numerous missense mutations. Four L-loop hVKORC1 mutants, suggested in vitro as either resistant (A41S, H68Y) or completely inactive (S52W, W59R), were studied in the oxidised state by numerical approaches (in silico). The DYNASOME and POCKETOME of each mutant were characterised and compared to the native protein, recently described as a modular protein composed of the structurally stable transmembrane domain (TMD) and the intrinsically disordered L-loop, exhibiting quasi-independent dynamics. The DYNASOME of mutants revealed that L-loop missense point mutations impact not only its folding and dynamics, but also those of the TMD, highlighting a strong mutation-specific interdependence between these domains. Another consequence of the mutation-induced effects manifests in the global changes (geometric, topological, and probabilistic) of the newly detected cryptic pockets and the alternation of the recognition properties of the L-loop with its redox protein. Based on our results, we postulate that (i) intra-protein allosteric regulation and (ii) the inherent allosteric regulation and cryptic pockets of each mutant depend on its DYNASOME; and (iii) the recognition of the redox protein by hVKORC1 (INTERACTOME) depend on their DYNASOME. This multifaceted description of proteins produces "omics" data sets, crucial for understanding the physiological processes of proteins and the pathologies caused by alteration of the protein properties at various "omics" levels. Additionally, such characterisation opens novel perspectives for the development of "allo-network drugs" essential for the treatment of blood disorders.

Clinical, economic, and humanistic impact of a multidisciplinary medication review with follow-up for anticoagulated patients treated with vitamin K antagonists in primary care: A cluster randomised controlled trial

BACKGROUND

Interdisciplinary collaboration between general practitioner, nurses and pharmacists can favour the control of patients treated with vitamin K antagonists (VKA), increasing their safety and effectiveness. The aim of the study was to evaluate the impact of pharmaceutical interventions on patients treated with VKA within the framework of a Pharmacotherapeutic Follow-up service on clinical, economic and humanistic outcomes.

METHODS

Controlled and randomized study in patients from two health areas of Zaragoza in treatment with VKA with Time in Therapeutic Range (TTR) according to the Rosendaal method less than 70% in the last 6 months. Patients were recruited at the pharmacy and assigned to two groups: control and intervention. A Pharmacotherapeutic Follow-up Program was established for the intervention group for 6 months. The outcome variables were INR stability, pharmacological adherence, vitamin K intake, knowledge about the use of acenocoumarol, quality of life, satisfaction with treatment, associated costs and avoided costs. A descriptive analysis was performed, and the Students' T test or Mann-Whitney U test was used for the association between quantitative variables and Chi-square or Fisher's test for qualitative variables.

RESULTS

A total of 123 patients were included, 65 in the intervention group (IG) and 58 in the control group (CG). A total of 108 interventions were conducted (1.7 interventions/patient) and the most common were those related to the proper taking of medications (41.0%). In IG, TTR (p = 0.019), adherence to treatment (p = 0.038) and knowledge about acenocoumarol (p = 0.031) improved, compared to CG. A higher proportion of patients in IG achieved a TTR>65% (p = 0.024). In addition, patients whose interventions were accepted by the physician (p = 0.027) and those who received vitamin K optimization interventions (p = 0.003) achieved TTR>65% in greater proportion.

CONCLUSIONS

Community pharmacist medication review, in collaboration with general practitioners improve knowledge and adherence of patients treated with oral anti-vitamin K agents and enhances the achievement of their therapeutic INR ranges. Investment needed to achieve this clinical impact is low and patient satisfaction is high.

TRIAL REGISTRATION

This study has been registered with Clinical Trials.gov dated 25/05/2017: NCT03154489.

The Safety of Direct Oral Anticoagulants Compared to Warfarin in Patients Hospitalized With Acute Kidney Injury

BACKGROUND

Direct oral anticoagulants (DOACs) are preferred over warfarin for many indications, though their safety has not been well established in patients with acute renal impairment.

OBJECTIVE

The purpose of this study was to evaluate the frequency of bleeding complications associated with DOACs compared with warfarin in patients admitted to the hospital with acute kidney injury (AKI).

METHODS

This was a retrospective cohort study evaluating patients admitted to the Penn Medicine Lancaster General Hospital with a diagnosis of AKI from October 2017 through September 2021 and receiving therapy with oral anticoagulants. Comparing DOACs with warfarin, the primary endpoint was the percent frequency of composite major and minor bleeding during the admission and within 30 days of discharge.

RESULTS

There were 112 hospitalization encounters included in the study. Of these, 42 (37.5%) patients were receiving warfarin and 70 (62.5%) patients were receiving DOAC therapy before admission. There was a higher frequency of the primary endpoint of bleeding in patients receiving DOACs as compared with warfarin, though this was not statistically significant (18.5% vs. 11.9%, respectively, P = 0.432). There were no differences between groups in the frequency of major bleeding, minor bleeding, or transfusions. Patients receiving DOAC therapy were more likely to experience anticoagulation-related readmissions or emergency department visits compared with patients on warfarin therapy (11.4% vs. 0%, P = 0.024).

CONCLUSION AND RELEVANCE

Direct oral anticoagulants and warfarin were associated with statistically similar rates of bleeding in patients presenting with AKI. Further research is necessary to elucidate if DOACs are safer than warfarin in this patient population.

Cost-Utility and Budget Impact Analysis of Implementing Anticoagulation Clinics and Point-of-Care Monitoring Devices in Anticoagulated Patients in Argentina

BACKGROUND

Worldwide, 1 % of the population receives anticoagulation therapy, with prevalence higher in older adults. Difficulties in the adequate management of these patients have led to the development of strategies focused on achieving therapeutic control and reducing adverse events with efficient use of resources.

OBJECTIVE

To estimate the cost utility and budget impact on the Argentinean health system of implementation of anticoagulation clinics (ACs) (with and without use of point-of-care [POC] CoaguChek^® devices [Roche Diagnostics International Ltd]) compared with the traditional laboratory method (non-AC settings) for the management of anticoagulated patients.

METHODS

For the cost-utility analysis, a cohort-based state transition model was designed to compare costs and health outcomes of implementing ACs for outpatient management of anticoagulated patients. The budget impact analysis used an analytical model to estimate the differential costs of implementing an AC and the expected adverse events avoided, and the differential costs of an international normalized ratio (INR) determination using a POC device rather than a conventional laboratory.

RESULTS

We calculated the study outcomes for a cohort of 1000 patients. Considering a 5 % discount rate, the use of ACs generated 13.9 additional quality-adjusted life-years (0.014 per patient) and 12.5 additional life-years (0.013 per patient). Incremental cost-effectiveness ratios of AC implementation with and without the use of POC devices compared with the scenario without ACs were dominant in both cases. In the probabilistic sensitivity analysis, nearly all simulated results were cost effective (i.e., below the 1 or 3 gross domestic product per capita thresholds). Budget impact analysis results showed AC implementation generated savings from the first year of implementation, with savings of AR $265,325 by year 5. The addition of POC devices in the ACs also generated savings as early as the first year of implementation, with savings of AR $488,072 by year 5 (AR $488 per patient).

CONCLUSIONS

Anticoagulation clinics are estimated to be cost effective and generate notable savings in the treatment of patients on long-term oral anticoagulant therapy when compared with non-AC settings. These savings are considerably higher when POC devices are added as part of the patient management, due to lower laboratory technician costs per INR determination.

Pharmacogenetic variants influence vitamin K anticoagulant dosing in patients with mechanical prosthetic heart valves

Background: Vitamin K antagonists (VKAs) are class I oral anticoagulants that are widely prescribed following surgical heart valve implantation. The objective of this study was to quantify the relative effects of VKORC1, CYP2C9 and CYP4F2 genotypes in predicting VKA dosing. Materials & methods: A total of 506 South Indian patients with mechanical prosthetic heart valves who were prescribed oral VKAs, such as warfarin or acenocoumarol, were genotyped. The discriminatory ability of mutant genotypes to predict dose categories and bleeding events was assessed using regression analysis. Results: The VKORC1 rs9923231, CYP2C9*3 and CYP4F2*3 mutant genotypes significantly influenced VKA-dose requirements and explained 27.47% of the observed dose variation. Conclusion: These results support pharmacogenetic screening for initial VKA dosing among South Indian patients with mechanical prosthetic heart valves.

When and how to use direct oral anticoagulants in patients with advanced chronic liver disease?

Direct oral anticoagulants (DOACs) emerged as effective and safe alternatives to traditional anticoagulants for the prevention and treatment of venous thromboembolic disease and the prevention of stroke in non-valvular atrial fibrillation. Patients with advanced chronic liver disease (ACLD) have a higher risk of thromboembolism and bleeding than patients with normal liver function. Therefore, anticoagulation and, in particular, direct oral anticoagulants play a central role. Portal vein thrombosis is a relatively frequent complication in patients with ACLD, but its treatment remains challenging. DOACs have been introduced in clinical practice and demonstrated similar efficacy and safety profiles compared with vitamin K antagonist and heparins. However, further data about the use of DOACs in patients suffering from ACLD are needed. This review summarizes current knowledge in terms of anticoagulation in patients with ACLD and focuses on the available data about the use of DOACs in this population.

Prevalence and management of antivitamin K overdose in a hospital setting

INTRODUCTION

Vitamin K antagonist (VKA) related adverse events are the first cause for iatrogenic events in France, particularly due to the narrow therapeutic margin. The risk of bleeding increases significantly when the INR level is ≥5. The main objective of this study was to assess the prevalence of VKA overdose in a hospital setting (at D2 of hospital entry) and to evaluate physicians' adherence to clinical practice guidelines for the management of VKA overdose according to French National Authority for Health recommendations.

METHODS

This single-center retrospective observational study consisted in querying the computerized database of a Parisian hospital on 21275INR determinations (3995 patients, 6813 hospital stays) performed between 2013 and 2018.

RESULTS

An INR level ≥5 was noted during 350 (6%) of the hospital stays, in 331 patients (of whom 57% were women). The mean age of the patient population with an INR≥5 was 81.1 years. Infection, heart failure and renal failure were the most frequent acute medical conditions for hospital admission. Twenty-three patients (7%) had a bleeding complication, 11 of which were major bleeding complications. Older age was associated with the severity of bleeding complications. Fifteen in-hospital deaths (4%) were reported, not related to bleeding events. The management of VKA overdose did not comply with the recommendations in 43% of cases, in particular for the highest INRs (50% of noncompliance for an INR>6.4). Non-compliance with recommendations for VKA overdose was related to: the delay until the INR was checked (44% of cases); the indication for prescribing vitamin K (34% of cases); the dose or route of administration of vitamin K therapy (19% of cases); and the interruption or not of VKA therapy (12% of cases).

CONCLUSION

The management of VKA overdose in a hospital setting remains non-compliant with the recommendations in almost half of the cases, mainly due to the delayed INR control and inappropriate management of vitamin K therapy. Computerized alert system would be helpful for personalized patient management and improved pharmacovigilance to prevent iatrogenic VKA events.

Efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism: a meta-analysis

Objective

Several trials had compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin for acute venous thromboembolism, but the results were incomplete. This updated review comprehensively assessed the efficacy and safety of non-vitamin K antagonist oral anticoagulants for venous thromboembolism.

Design

Meta-analysis of randomised control trials. Six databases were searched from January 2000 to December 2018.

Setting

Adult patients had got non-vitamin K antagonist oral anticoagulants or warfarin for venous thromboembolism.

Participants

Randomised control trials that compared the efficacy and safety between non-vitamin K antagonist oral anticoagulants and warfarin.

Main outcome measures

The efficacy and safety of non-vitamin K antagonist oral anticoagulants .

Results

Seven studies involving 29,879 cases were included, among which 14,943 cases were assigned to non-vitamin K antagonist oral anticoagulants group and 14,936 cases to warfarin group. Meta-analysis showed that compared with warfarin, recurrent venous thromboembolism (odds ratio 0.94 [95% confidence interval 0.81 to 1.11]), death related to venous thromboembolism or fatal pulmonary embolism (odds ratio 1.00 [95% confidence interval 0.63 to 1.60]), symptomatic deep-vein thrombosis (odds ratio 0.88 [95% confidence interval 0.72 to 1.09]), symptomatic nonfatal pulmonary embolism (odds ratio 1.03 [(95% confidence interval 0.82 to 1.30]) and all deaths (odds ratio 0.92 [95% confidence interval 0.76 to 1.12]) are similar in non-vitamin K antagonist oral anticoagulants group, but major bleeding event (odds ratio 0.61 [95% confidence interval 0.50 to 0.75]) and clinically relevant non-major bleeding event (odds ratio [95% confidence interval 0.53 to 0.85]) are less in non-vitamin K antagonist oral anticoagulants group. .

Conclusions

For the treatment of venous thromboembolism, non-vitamin K antagonist oral anticoagulants is as effective as warfarin, and has a better safety profile than warfarin.

Nursing self-efficacy for oral anticoagulant therapy management: Development and initial validation of a theory-grounded scale

AIM

This study aimed to develop and validate a nursing self-efficacy scale for OAC management (SE-OAM).

BACKGROUND

Oral anticoagulant therapy (OAC) requires specific nursing competencies. Given that self-efficacy acts as a proxy assessment of nursing competence, its measurement is pivotal for addressing educational programs to enhance nursing competence in managing OAC. Thus far, the measurement of self-efficacy in OAC is undermined by the unavailability of valid and reliable tools.

METHODS

A multi-method and multi-phase design was adopted: Phase one was a methodological study encompassing developmental tasks for generating items. Phase two comprised the validation process for determining the content validity, construct and concurrent validity, and internal consistency through two cross-sectional data collections.

RESULTS

In total, 190 nurses were enrolled for determining the psychometric structure of the SE-OAM through an exploratory approach, and 345 nurses were subsequently enrolled to corroborate its most plausible factor structure derived from the exploratory analysis. The SE-OAM showed evidence of face and content validity, adequate construct, concurrent validity, good internal consistency, and stability. The final version of the scale encompassed 21 items kept by five domains: clinical management, care management, education, clinical monitoring, and care monitoring.

CONCLUSIONS

The SE-OAM showed evidence of initial validity and reliability, fulfilling a current gap in the availability of tools for measuring nursing self-efficacy in managing OAC. SE-OAM could be strategic for performing research to improve the quality of OAC management by enhancing nursing self-efficacy.

Viscoelastometry for detecting oral anticoagulants

Background

Determination of anticoagulant therapy is of pronounced interest in emergency situations. However, routine tests do not provide sufficient insight. This study was performed to investigate the impact of anticoagulants on the results of viscoelastometric assays using the ClotPro device.

Methods

This prospective, observational study was conducted in patients receiving dabigatran, factor Xa (FXa)-inhibitors, phenprocoumon, low molecular weight heparin (LMWH) or unfractionated heparin (UFH) (local ethics committee approval number: 17–525-4). Healthy volunteers served as controls. Viscoelastometric assays were performed, including the extrinsic test (EX-test), intrinsic test (IN-test) Russel’s viper venom test (RVV-test), ecarin test (ECA-test), and the tissue plasminogen activator test (TPA-test).

Results

70 patients and 10 healthy volunteers were recruited. Clotting time in the EX-test (CT_EX-test) was significantly prolonged versus controls by dabigatran, FXa inhibitors and phenprocoumon. CT_IN-test was prolonged by dabigatran, FXa inhibitors and UFH. Dabigatran, FXa inhibitors and UFH significantly prolonged CT_RVV-test in comparison with controls (median 200, 207 and 289 vs 63 s, respectively; all p < 0.0005). Only dabigatran elicited a significant increase in CT_ECA-test compared to controls (median 307 vs 73 s; p < 0.0001). CT_ECA-test correlated strongly with dabigatran plasma concentration (measured by anti-IIa activity; r = 0.9970; p < 0.0001) and provided 100% sensitivity and 100% specificity for detecting dabigatran. Plasma concentrations (anti-XA activity) of FXa inhibitors correlated with CT_RVV-test (r = 0.7998; p < 0.0001), and CT_RVV-test provided 83% sensitivity and 64% specificity for detecting FXa inhibitors.

Conclusions

In emergency situations, ClotPro viscoelastometric assessment of whole-blood samples may help towards determining the presence and type of anticoagulant class that a patient is taking.

Trial registration

German clinical trials database ID: DRKS00015302.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-021-00267-w.