Guidelines on oral anticoagulation with warfarin - fourth edition

Beyond Population-Level Targets for Drug Concentrations: Precision Dosing Needs Individual-Level Targets that Include Superior Biomarkers of Drug Responses

The purpose of precision dosing is to increase the chances of therapeutic success in individual patients. This is achieved in practice by adjusting doses to reach precision dosing targets determined previously in relevant populations, ideally with robust supportive evidence showing improved clinical outcomes compared with standard dosing. But is this implicit assumption of translatable population-level precision dosing targets correct and the best for all patients? In this review, the types of precision dosing targets and how they are determined are outlined, problems with the translatability of these targets to individual patients are identified, and ways forward to address these challengers are proposed. Achieving improved clinical outcomes to support precision dosing over standard dosing is currently hampered by applying population-level targets to all patients. Just as "one-dose-fits-all" may be an inappropriate philosophy for drug treatment overall, a "one-target-fits-all" philosophy may limit the broad clinical benefits of precision dosing. Defining individual-level precision dosing targets may be needed for greatest therapeutic success. Superior future precision dosing targets will integrate several biomarkers that together account for the multiple sources of drug response variability.

Quality of Life of Patients Receiving Warfarin Therapy at a Tertiary Care Centre in Indonesia Using DASS (Duke Anticoagulation Satisfaction Scale)

Purpose

This study aimed to examine the quality of life of patients receiving warfarin therapy at Dr. Hasan Sadikin Central General Hospital, and its relationship with demographic factors.

Patients and Methods

The procedures started with the submission of a study permit, followed by validation of the Duke Anticoagulation Satisfaction Scale (DASS) questionnaire. In addition, the validated questionnaire was completed by the participants, and significant variables were analyzed using the chi-square method for multivariate analysis.

Results

The results showed that the questionnaire was valid and could be used for further analyses. Among the 88 selected participants, 52 and 36 had scoring categories <56.266 and 56.266 ≤ x ≤ 143.734, respectively, with no patients having a scoring category > 143.734. In addition, participants with low education and aged ≥ 52 years were 4.916 and 3.161 times more at risk of having quality of life score of 56.266 ≤ x ≤ 143.734, respectively. Based on the results, the average quality of life score of patients was 59.66. Participants with low educational levels and those aged ≥ 52 years were at a higher risk of having quality of life score of 56.266 ≤ x ≤ 143.734.

Conclusion

In summary, a lower quality of life score was linked to increased comfort and satisfaction among patients receiving warfarin treatment. Additionally, these patients experienced fewer feelings of limitations and inconveniences related to their treatment plans.

Comparative effectiveness of warfarin management strategies: a systematic review and network meta-analysis

Background

The management of warfarin therapy presents clinical challenges due to its narrow therapeutic index. We aimed to evaluate the comparative effectiveness of different management strategies in patients using warfarin.

Methods

PubMed, Embase, Cochrane CENTRAL, CINAHL, and EBSCO Open Dissertation were searched from inception to 8 May 2024. Randomized controlled trials that compared the following interventions: patient self-management (PSM), patient self-testing (PST), anticoagulation management services (AMS), and usual care in patients prescribed warfarin for any indication were included. Risk ratios (RR) with 95% confidence interval (CI) were estimated using a random-effects model. Surface under the cumulative ranking curves (SUCRA) were used to rank different interventions. The certainty of evidence was assessed using the Confidence in Network Meta-Analysis (CINeMA) online platform. This study is registered with PROSPERO (CRD42023491978).

Findings

Twenty-eight trials involving 8100 participants were included, with follow-up periods of 1-24 months. Mean warfarin dosages were 4.9-7.2 mg/day. Only PSM showed a significant reduction of major TE risk compared with usual care (RR = 0.41; 95% CI: 0.24, 0.71; I2 = 0.0%) with moderate certainty of evidence. The 97.6% SUCRA also supported the beneficial effects of PSM over other interventions. The combined direct and indirect evidence showed significantly higher TTR in PSM compared with usual care (MD = 7.39; 95% CI: 2.39, 12.39), with very low certainty. However, direct evidence showed non-significant TTR improvement (MD = 6.49; 95% CI: -3.09, 16.07, I2 = 96.1%). No differences across various strategies were observed in all-cause mortality, major bleeding, stroke, transient ischemic attack, and hospitalization.

Interpretation

PSM reduces the risk of major TE events compared with usual care, tends to improve anticoagulation control, and should be considered where appropriate.

Funding

Agency for Healthcare Research and Quality (grant ID 5R18HS027960).

Strategies to prevent blood loss and reduce transfusion in emergency general surgery, WSES-AAST consensus paper

Emergency general surgeons often provide care to severely ill patients requiring surgical interventions and intensive support. One of the primary drivers of morbidity and mortality is perioperative bleeding. In general, when addressing life threatening haemorrhage, blood transfusion can become an essential part of overall resuscitation. However, under all circumstances, indications for blood transfusion must be accurately evaluated. When patients decline blood transfusions, regardless of the reason, surgeons should aim to provide optimal care and respect and accommodate each patient's values and target the best outcome possible given the patient's desires and his/her clinical condition. The aim of this position paper was to perform a review of the existing literature and to provide comprehensive recommendations on organizational, surgical, anaesthetic, and haemostatic strategies that can be used to provide optimal peri-operative blood management, reduce, or avoid blood transfusions and ultimately improve patient outcomes.

A Randomized Trial Comparing Standard of Care to Bayesian Warfarin Dose Individualization

The quality of warfarin treatment may be improved if management is guided by the use of models based upon pharmacokinetic-pharmacodynamic theory. A prospective, two-armed, single-blind, randomized controlled trial compared management aided by a web-based dose calculator (NextDose) with standard clinical care. Participants were 240 adults receiving warfarin therapy following cardiac surgery, followed up until the first outpatient appointment at least 3 months after warfarin initiation. We compared the percentage of time spent in the international normalized ratio acceptable range (%TIR) during the first 28 days following warfarin initiation, and %TIR and count of bleeding events over the entire follow-up period. Two hundred thirty-four participants were followed up to day 28 (NextDose: 116 and standard of care: 118), and 228 participants (114 per arm) were followed up to the final study visit. Median %TIR tended to be higher for participants receiving NextDose guided warfarin management during the first 28 days (63 vs. 56%, P = 0.13) and over the entire follow-up period (74 vs. 71%, P = 0.04). The hazard of clinically relevant minor bleeding events was lower for participants in the NextDose arm (hazard ratio: 0.21, P = 0.041). In NextDose, there were 89.3% of proposed doses accepted by prescribers. NextDose guided dose management in cardiac surgery patients requiring warfarin was associated with an increase in %TIR across the full follow-up period and fewer hemorrhagic events. A theory-based, pharmacologically guided approach facilitates higher quality warfarin anticoagulation. An important practical benefit is a reduced requirement for clinical experience of warfarin management.

The 2023 WSES guidelines on the management of trauma in elderly and frail patients

BACKGROUND

The trauma mortality rate is higher in the elderly compared with younger patients. Ageing is associated with physiological changes in multiple systems and correlated with frailty. Frailty is a risk factor for mortality in elderly trauma patients. We aim to provide evidence-based guidelines for the management of geriatric trauma patients to improve it and reduce futile procedures.

METHODS

Six working groups of expert acute care and trauma surgeons reviewed extensively the literature according to the topic and the PICO question assigned. Statements and recommendations were assessed according to the GRADE methodology and approved by a consensus of experts in the field at the 10th international congress of the WSES in 2023.

RESULTS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage, including drug history, frailty assessment, nutritional status, and early activation of trauma protocol to improve outcomes. Acute trauma pain in the elderly has to be managed in a multimodal analgesic approach, to avoid side effects of opioid use. Antibiotic prophylaxis is recommended in penetrating (abdominal, thoracic) trauma, in severely burned and in open fractures elderly patients to decrease septic complications. Antibiotics are not recommended in blunt trauma in the absence of signs of sepsis and septic shock. Venous thromboembolism prophylaxis with LMWH or UFH should be administrated as soon as possible in high and moderate-risk elderly trauma patients according to the renal function, weight of the patient and bleeding risk. A palliative care team should be involved as soon as possible to discuss the end of life in a multidisciplinary approach considering the patient's directives, family feelings and representatives' desires, and all decisions should be shared.

CONCLUSIONS

The management of elderly trauma patients requires knowledge of ageing physiology, a focused triage based on assessing frailty and early activation of trauma protocol to improve outcomes. Geriatric Intensive Care Units are needed to care for elderly and frail trauma patients in a multidisciplinary approach to decrease mortality and improve outcomes.

Defining a metrologically traceable and sustainable calibration hierarchy of international normalized ratio for monitoring of vitamin K antagonist treatment in accordance with International Organization for Standardization (ISO) 17511:2020 standard: communication from the International Federation of Clinical Chemistry and Laboratory Medicine-SSC/ISTH working group on prothrombin time/international normalized ratio standardization

Calibration of prothrombin time (PT) in terms of international normalized ratio (INR) has been outlined in "Guidelines for thromboplastins and plasmas used to control oral anticoagulant therapy" (World Health Organization, 2013). The international standard ISO 17511:2020 presents requirements for manufacturers of in vitro diagnostic (IVD) medical devices (MDs) for documenting the calibration hierarchy for a measured quantity in human samples using a specified IVD MD. The objective of this article is to define an unequivocal, metrologically traceable calibration hierarchy for the INR measured in plasma as well as in whole blood samples. Calibration of PT and INR for IVD MDs according to World Health Organization guidelines is similar to that in cases where there is a reference measurement procedure that defines the measurand for value assignment as described in ISO 17511:2020. We conclude that, for PT/INR standardization, the optimal calibration hierarchy includes a primary process to prepare an international reference reagent and measurement procedure that defines the measurand by a value assignment protocol conforming to clause 5.3 of ISO 17511:2020. A panel of freshly prepared human plasma samples from healthy adult individuals and patients on vitamin K antagonists is used as a commutable secondary calibrator as described in ISO 17511:2020. A sustainable metrologically traceable calibration hierarchy for INR should be based on an international protocol for value assignment with a single primary reference thromboplastin and the harmonized manual tilt tube technique for clotting time determination. The primary international reference thromboplastin reagent should be used only for calibration of successive batches of the secondary reference thromboplastin reagent.

Splenic artery embolisation for blunt splenic trauma: 10 years of practice at a trauma centre

INTRODUCTION

Splenic artery embolisation (SAE) has transformed the management of splenic trauma. The aim of this study was to review the outcomes and postprocedural management of blunt splenic trauma patients treated with SAE at a trauma centre over a 10-year period.

METHODS

Details of patients undergoing SAE for blunt trauma between January 2012 and January 2022 were acquired from a prospectively maintained database. Patient records were reviewed for demographic information, splenic injury grades, embolisation efficacy, complications, and associated injuries and mortality. Data relating to Injury Severity Scores (ISS) and postprocedural practice (vaccinations, antibiotic prescribing, follow-up imaging) were also obtained.

RESULTS

Thirty-six patients (24 male, 12 female) with a median age of 42.5 years (range 13-97 years) were identified. American Association for the Surgery of Trauma splenic injury grades were III (n = 7), IV (n = 20) and V (n = 9). Seventeen patients had isolated splenic injury and 19 had additional injuries to other organ systems. Median ISS was 18.5 (range 5-50). SAE succeeded first time in 35/36 cases, and upon the second attempt in 1/36 cases. No patients died because of splenic injury or SAE although four patients with polytrauma died owing to other injuries. SAE complications occurred in 4/36 cases. For survivors, vaccinations were administered in 17/32 cases, and long-term antibiotics were initiated in 14/32 cases. Formal follow-up imaging was arranged in 9/32 cases.

CONCLUSIONS

These data show that SAE is an effective means of controlling splenic haemorrhage secondary to blunt trauma with no patient requiring subsequent laparotomy. Major complications occurred in 11% of cases. Follow-up practice varied regarding further imaging, antibiotic and vaccination administration.

Plasma: indications, controversies, and opportunities

Plasma is overused as a blood product worldwide; however, data supporting appropriate use of plasma is scant. Its most common utilization is for treatment of coagulopathy in actively bleeding patients; it is also used for coagulation optimization prior to procedures with specific coagulation profile targets. A baseline literature review in PUBMED and Google Scholar was done (1 January 2000 to 1 June 2023), utilizing the following search terms: plasma, fresh frozen plasma, lyophilized plasma, indications, massive transfusion protocol, liver disease, warfarin reversal, cardiothoracic surgery, INR < 2. An initial review of the titles and abstracts excluded all articles that were not focused on transfusional medicine. Additional references were obtained from citations within the retrieved articles. This narrative review discusses the main indications for appropriate plasma use, mainly coagulation factor replacement, major hemorrhage protocol, coagulopathy in liver disease, bleeding in the setting of vitamin K antagonists, among others. The correlation between concentration of coagulation factors and INR, as well as the proper plasma dosing with its volume being weight-based, is also discussed. A high value approach to plasma utilization is supported with a review of the clinical situations where plasma is overutilized or unnecessary. Finally, a discussion of novel plasma products is presented for enhanced awareness.

Efficacy and Safety of Oral Anticoagulants in Older Adult Patients With Atrial Fibrillation: Pairwise and Network Meta-Analyses

OBJECTIVE

To evaluate the efficacy and safety of oral anticoagulants for older adult patients with atrial fibrillation (AF).

DESIGN

Pairwise and network meta-analyses.

SETTING AND PARTICIPANTS

Patients with AF aged ≥75 years.

METHODS

PubMed, Embase, and the Cochrane library were searched for published randomized controlled trials and adjusted observational studies evaluating the use of a non-vitamin K antagonist oral anticoagulants (NOACs), vitamin K antagonist, or antiplatelet drug for the prevention of stroke. The primary efficacy and safety outcomes were the composite of stroke and systemic embolism (SSE) and major bleedings.

RESULTS

This study included 38 studies enrolling 1,022,908 older adult patients with AF. Results from pairwise meta-analyses showed that NOACs were superior to warfarin for all outcomes, except that dabigatran increased the risk of gastrointestinal (GI) bleedings. Aspirin was associated with a higher risk of SSE and ischemic stroke than warfarin or NOACs. Results of network meta-analyses indicated that apixaban significantly reduced the risk of SSE, major bleedings, and GI bleedings than warfarin, rivaroxaban, and dabigatran. Apixaban, edoxaban, rivaroxaban, and dabigatran reduced the risk of ischemic stroke and intracranial bleeding compared to warfarin. Dabigatran showed lower risk of all-cause mortality than warfarin and of intracranial bleeding than rivaroxaban.

CONCLUSIONS AND IMPLICATIONS

NOACs are of at least equal efficacy, or even superior to warfarin. The safety profile of individual NOAC agents was significantly different, as apixaban performs better than the other oral anticoagulants in reducing major bleeding and GI bleeding, whereas dabigatran increased the risk of GI bleeding.

SAIL study of stroke, systemic embolism and bleeding outcomes with warfarin anticoagulation in non-valvular atrial fibrillation (S4-BOW-AF)

Aims

In patients with non-valvular atrial fibrillation (NVAF) prescribed warfarin, the association between guideline defined international normalised ratio (INR) control and adverse outcomes in unknown. We aimed to (i) determine stroke and systemic embolism (SSE) and bleeding events in NVAF patients prescribed warfarin; and (ii) estimate the increased risk of these adverse events associated with poor INR control in this population.

Methods and results

Individual-level population-scale linked patient data were used to investigate the association between INR control and both SSE and bleeding events using (i) the National Institute for Health and Care Excellence (NICE) criteria of poor INR control [time in therapeutic range (TTR) <65%, two INRs <1.5 or two INRs >5 in a 6-month period or any INR >8]. A total of 35 891 patients were included for SSE and 35 035 for bleeding outcome analyses. Mean CHA2DS2-VASc score was 3.5 (SD = 1.7), and the mean follow up was 4.3 years for both analyses. Mean TTR was 71.9%, with 34% of time spent in poor INR control according to NICE criteria.SSE and bleeding event rates (per 100 patient years) were 1.01 (95%CI 0.95-1.08) and 3.4 (95%CI 3.3-3.5), respectively, during adequate INR control, rising to 1.82 (95%CI 1.70-1.94) and 4.8 (95% CI 4.6-5.0) during poor INR control.Poor INR control was independently associated with increased risk of both SSE [HR = 1.69 (95%CI = 1.54-1.86), P < 0.001] and bleeding [HR = 1.40 (95%CI 1.33-1.48), P < 0.001] in Cox-multivariable models.

Conclusion

Guideline-defined poor INR control is associated with significantly higher SSE and bleeding event rates, independent of recognised risk factors for stroke or bleeding.

Severe Bleeding Risk of Direct Oral Anticoagulants Versus Vitamin K Antagonists for Stroke Prevention and Treatment in Patients with Atrial Fibrillation: A Systematic Review and Network Meta-Analysis

PURPOSE

We aimed to determine the safety of direct oral anticoagulants (DOACs) for stroke prevention and treatment in patients with atrial fibrillation (AF).

METHODS

A systematic search of four databases (PubMed, EMBASE, Web of Science, and Cochrane Library) was performed to identify randomized controlled trials (RCTs) reporting severe bleeding events in patients taking DOACs or vitamin K antagonists (VKAs). In this frequency-based network meta-analysis, odds ratios and 95% confidence intervals were used for reporting. Based on the surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Twenty-three RCTs met the inclusion criteria, and a total of 87,616 patients were enrolled. The bleeding safety of DOACs for stroke prevention and treatment in patients with AF was ranked from highest to lowest as follows: fatal bleeding: edoxaban (SUCRA,80.2), rivaroxaban (SUCRA,68.3), apixaban (SUCRA,48.5), dabigatran (SUCRA,40.0), VKAs (SUCRA,12.9); major bleeding: dabigatran (SUCRA,74.0), apixaban (SUCRA,71.5), edoxaban (SUCRA,66.5), rivaroxaban (SUCRA,22.7), VKAs (SUCRA,15.4); gastrointestinal bleeding: apixaban (SUCRA,55.9), VKAs (SUCRA,53.7), edoxaban (SUCRA,50.5), rivaroxaban (SUCRA,50.4), dabigatran (SUCRA,39.5); intracranial hemorrhage: dabigatran (SUCRA,84.6), edoxaban (SUCRA,74.1), apixaban (SUCRA,65.8), rivaroxaban (SUCRA,24.4), VKAs (SUCRA,1.1).

CONCLUSION

Based on current evidence, for stroke prevention and treatment in patients with AF, the most safe DOAC is edoxaban in terms of fatal bleeding; dabigatran in terms of major bleeding and intracranial hemorrhage and apixaban in terms of gastrointestinal bleeding. However, given the nature of indirect comparisons, more high-quality evidence from head-to-head comparisons is still needed to confirm them.

ICSH guidance for INR and D-dimer testing using point of care testing in primary care

This guideline has been written on behalf of the International Council for Standardisation in Haematology (ICSH) and focuses on two point of care haematology tests used within primary care, namely International Normalised Ratio (INR) and D-dimer. Primary care covers out of hospital settings and can include General Practice (GP), Pharmacy and other non-hospital settings (although these guidelines would also be applicable to hospital out-patient settings). The recommendations are based on published data in peer reviewed literature and expert opinion; they should supplement regional requirements, regulations or standards.

Genetic heterogeneity in cardiovascular disease across ancestries: Insights for mechanisms and therapeutic intervention

Cardiovascular diseases (CVDs) are complex in their aetiology, arising due to a combination of genetics, lifestyle and environmental factors. By nature of this complexity, different CVDs vary in their molecular mechanisms, clinical presentation and progression. Although extensive efforts are being made to develop novel therapeutics for CVDs, genetic heterogeneity is often overlooked in the development process. By considering molecular mechanisms at an individual and ancestral level, a richer understanding of the influence of environmental and lifestyle factors can be gained and more refined therapeutic interventions can be developed. It is therefore expedient to understand the molecular and clinical heterogeneity in CVDs that exists across different populations. In this review, we highlight how the mechanisms underlying CVDs vary across diverse population ancestry groups due to genetic heterogeneity. We then discuss how such genetic heterogeneity is being leveraged to inform therapeutic interventions and personalised medicine, highlighting examples across the CVD spectrum. Finally, we present an overview of how polygenic risk scores and Mendelian randomisation can foster more robust insight into disease mechanisms and therapeutic intervention in diverse populations. Fulfilment of the vision of precision medicine requires more exhaustive leveraging of the genetic variability across diverse ancestry populations to improve our understanding of disease onset, progression and response to therapeutic intervention.

Budget impact analysis of a bovine pericardial aortic bioprosthesis versus mechanical aortic valve replacement in adult patients with aortic stenosis in Romania

AIMS

An analysis of the budget impact of using a bovine pericardial aortic bioprosthesis (BPAB) or a mechanical valve (MV) in aortic stenosis (AS) patients in Romania.

MATERIALS AND METHODS

A decision-tree with a partitioned survival model was used to predict the financial outcomes of using either a BPAB (the Carpentier-Edwards Perimount Magna Ease Valve) or MV in aortic valve replacement (AVR) procedure over a 5-year period. The budget impact of various resource consumption including disabling strokes, reoperations, minor thromboembolic events, major bleeding, endocarditis, anticoagulation treatment and monitoring, and echocardiogram assessments were compared for both types of valves. One-way sensitivity analyses (OWSA) were conducted on the input costs and probabilities.

RESULTS

The use of BPAB compared to MV approaches budget neutrality due to incremental savings year-on-year. The initial surgical procedure and reoperation costs for BPAB are offset by savings in acenocoumarol use, disabling strokes, major bleeding, minor thromboembolic events, and anticoagulation complications. The cost of the initial procedure per patient is 460 euros higher for a BPAB due to the higher valve acquisition cost, although this is partially offset by a shorter hospital stay. The OWSA shows that the total procedure costs, including the hospital stay, are the primary cost drivers in the model.

LIMITATIONS

Results are limited by cost data aggregation in the DRG system, exclusion of costs for consumables and capital equipment use, possible underestimation of outpatient complication costs, age-related variations of event rates, and valve durability.

CONCLUSIONS

Adopting BPAB as a treatment option for AS patients in Romania can lead to cost savings and long-term economic benefits. By mitigating procedure costs and increasing anticoagulation treatment costs, BPAB offers a budget-neutral option that can help healthcare providers, policymakers, and patients alike manage the growing burden of AS in Romania.

Challenges in managing patients on anticoagulation: Thrombocytopenia, resumption after bleeding and recurrent thrombosis

Prescribing of anticoagulation is increasing worldwide. This is partly reflective of an aging population with cardiovascular comorbidities such as arrhythmias and prosthetic heart valves, alongside improvements in cancer treatments and survival. In this review, we discuss three common challenges faced by clinicians. These concern the management of patients with thrombosis and thrombocytopenia, resumption of anticoagulation in patients with a history of gastrointestinal or intracranial haemorrhage, and how to approach and treat a patient with recurrent thrombosis on anticoagulation. We consider the available evidence including relevant published recommendations and propose practical management suggestions to aid clinicians faced with these dilemmas.

Understanding patient assessment and treatment in deep vein thrombosis

Deep vein thrombosis (DVT) commonly develops in the deep veins of the legs, but it can potentially form in any part of the body. There are several risk factors associated with DVT including prolonged immobility, malignancy, recent surgery and family history. One of the main risks of DVT is that the thrombus that has formed in a vein may travel through the body and become lodged in the pulmonary system, causing a pulmonary embolism, which is life-threatening. In the UK, specialist services and diagnostic pathways have been developed to speed up the diagnosis and treatment of DVT, many of which are now nurse-led. This article uses a case study to outline the assessment of patients with suspected DVT and the treatment of patients with a confirmed diagnosis of DVT.

Warfarin Overdose in an Adolescent Not Dependent on Anticoagulation: Reversal Strategy and Kinetics

INTRODUCTION

Warfarin induces coagulopathy. Guidelines protocolize reversal of supratherapeutic international normalized ratio (INR) in patients dependent on anticoagulation, but practices vary for reversing warfarin-induced coagulopathy after overdose in non-warfarin-dependent patients.

CASE REPORT

This is the report of a 15-year-old female who ingested her father's warfarin (100-200 mg) in a self-harm attempt. At hour 24 post-ingestion, her INR was 2.00 and she was admitted for monitoring. Reversal of coagulopathy was initially deferred pending the INR trend. The INR was 5.10 at hour 60 and 2.5 mg oral vitamin K1 (VK1) was given. At hour 85, the INR peaked at 6.67 and she received a second oral dose of 2.5 mg VK1. On day 8, she was medically cleared with an INR of 1.31. On day 11, she developed lower abdominal pain and diarrhea. Imaging revealed a duodenal hematoma, and symptoms improved spontaneously. She was again medically cleared 13 days post-ingestion. Her serum warfarin concentration peaked at 19 mcg/mL at hour 46. Serial warfarin concentrations were obtained, demonstrating first-order elimination kinetics and a 30-hour half-life.

CONCLUSION

A restrictive approach to coagulopathy reversal in non-warfarin-dependent patients with intentional warfarin overdose may result in worsening coagulopathy, bleeding, and lengthy hospital stay. Given the risk for significant, prolonged coagulopathy, these patients should be treated early with VK1, with subsequent serial INR monitoring and probable additional VK1 dosing. Delayed peak warfarin concentrations support consideration of gastrointestinal decontamination in late presenters.

Lumbar puncture: considerations, procedure, and complications

Lumbar puncture is an important technique used to obtain cerebrospinal fluid, administer medications, and monitor intracerebral pressure. As essential invasive approach to diagnosing and treating central nervous system disorders, clinicians should be familiar with lumbar puncture. This review includes the considerations, contraindications, procedures, and complications of lumbar puncture.

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.

Thrombosis and Anticoagulation Therapy in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune inflammatory disease in which pathogenic autoantibodies and immune complexes are formed and mediate multiple organ and tissue damage. Thrombosis is one of the most common causes of death in patients with SLE. Anticoagulant therapy blocks the vicious cycle between inflammation and thrombosis, which may greatly improve the long-term prognosis of patients with SLE. However, the etiology and pathogenesis of this disease are very complicated and have not yet been fully clarified. Therefore, in the present review, we will highlight the characteristics and mechanisms of thrombosis and focus on the anticoagulant drugs commonly used in clinical practice, thus, providing a theoretical basis for scientific and reasonable anticoagulant therapy in clinical practice.

Development of an Adherence to Anticoagulant Therapy Scale: A Validity and Reliability Study

Purpose: Anticoagulants are an important group of drugs used by many patients with different diseases. There are general adherence scales that measure adherence to treatment in the literature. However, the correct use of the drug alone is not sufficient for adherence with warfarin therapy. To develop Anticoagulant Therapy Adherence Scale for use in patients on warfarin and to examine psycholinguistic and psychometric properties. Methods: The research was of a methodological and consisted of 170 patients. The validity of the scale was tested by using content validity, explanatory and confirmatory factor analysis. The reliability of the scale was examined by utilizing item-total scale correlations and Cronbach’s alpha. Results: After the scale items were created, opinions were received from twenty experts and content validity indexes were found to be above 0.80. In the explanatory factor analysis, a 3-factor structure with factor loads between 0.30 and 0.81 was obtained. Fit indices obtained in the confirmatory factor analysis were as follows: χ2 = 181.116, df = 116 χ2/df value 1.561, Root Mean Square Error of Approximation (RMSEA) = 0.058, Comparative Fit Index (CFI): 0.88 and Goodness Fit Index (GFI): 0.88. Item-total scale correlation coefficients were found to range between 0.57 and 0.25. The Cronbach's alpha reliability coefficient was 0.74 for the overall scale and 0.63, 0.77 and 0.65 for its subscales. Conclusions: ATAS was found to be a valid and reliable measurement tool in Turkish population. The scale can be used by healthcare professionals to evaluate patients' use of warfarin in a standard way.

Proximal femur fractures in patients taking anti-coagulants: has anything changed?

With an ever-ageing population, the incidence of hip fractures is increasing worldwide. Increasing age is not just associated with increasing fractures but also increasing comorbidities and polypharmacy.

Consequently, a large proportion of patients requiring hip fracture surgery (HFS) are also prescribed antiplatelet and anti-coagulant medication. There remains a clinical conundrum with regards to how such medications should affect surgery, namely with regards to anaesthetic options, timing of surgery, stopping and starting the medication as well as the need for reversal agents.

Herein, we present the up-to-date evidence on HFS management in patients taking blood-thinning agents and provide a summary of recommendations based on the existing literature.

Clinical Outcomes of Different Warfarin Self-Care Strategies: A Systematic Review and Network Meta-Analysis

AIM

To compare the effects of different strategies for warfarin self-care.

METHODS

PubMed, EMBASE, CENTRAL, CINAHL, ProQuest Dissertations & Theses, and OpenGrey were searched from inception to August 2021. Randomized controlled trials (RCTs) of warfarin self-care, either patient self-testing (PST) or patient self-management (PSM), were included. Self-care approaches were classified based on the TIP framework (theme, intensity, provider): (1) PST ≥1/week via e-Health (PST/High/e-Health); (2) PST ≥1/week by health care practitioner (PST/High/HCP); (3) PST <1/week via e-Health (PST/Low/e-Health); (4) PSM ≥1/week by e-Health (PSM/High/e-Health); (5) PSM ≥1/week by patient (PSM/High/Pt); (6) PSM <1/week by patient (PSM/Low/Pt); and (7) PSM with flexible frequency by patient (PSM/Flex/Pt). Mean differences (MDs) and risk ratios (RRs) with 95% confidence interval (CI) were estimated using frequentist network meta-analyses with a random-effects model. The certainty of evidence was evaluated using CINeMA (Confidence in Network Meta-Analysis).

RESULTS

Sixteen RCTs involving 5,895 participants were included. When compared with usual care, time in therapeutic range was higher in PSM/High/Pt and PST/High/e-Health with MD [95% CI] of 7.67% [0.26-15.08] and 5.65% [0.04-11.26], respectively. The certainty of evidence was rated as moderate for these findings. The risk of thromboembolic events was lower in the PSM/Flex/Pt group when compared with PST/High/e-Health (RR: 0.39 [0.20-0.77]) and usual care (RR: 0.38 [0.17-0.88]) with low and very low level of evidence, respectively. There was no significant difference in the proportion of international normalized ratio (INR) values in range, major bleeding, and all-cause mortality among different self-care features.

CONCLUSION

Patient self-care (either PST or PSM) by measuring INR values at least once weekly is more effective in controlling the INR level.

The Transcultural Adaptation and Validation of the Chinese Version of the Duke Anticoagulation Satisfaction Scale

Background: The Duke Anticoagulation Satisfaction Scale (DASS) offers a method to measure the quality of life and satisfaction of patients taking oral anticoagulants. The study aimed to validate the Chinese version of the DASS in Chinese patients on anticoagulation therapy. Methods: The DASS was translated, back-translated, and transculturally adapted into the Chinese version and then administered to participants taking oral anticoagulants in a physician-pharmacist collaborative anticoagulation clinic at a tertiary teaching hospital from October 2019 to December 2020. Reliability was analyzed through Cronbach's alpha (α) and split-half reliability. Confirmatory factor analysis was performed to test the structural validity of the scale. Exploratory factor analysis was performed for items in the scales using the varimax rotation method. Results: A total of 189 patients completed the Chinese version of the DASS. Four dimensions and 23 items were included, with Cronbach's α values of 0.89, 0.81, 0.89, and 0.74 for limitations on physical activities, diet restrictions, hassles and burdens, and positive psychological effect, respectively. Cronbach's α coefficient of whole scale was 0.91. The split-half reliability of this scale is 0.747 (>0.7). Conclusion: The Chinese version of the DASS indicated excellent reliability and validity, compared to the original version. It could provide a practical instrument for healthcare practitioners to evaluate satisfaction and quality of life for anticoagulated patients in China. The difference in quality of life between patients taking warfarin and novel oral anticoagulants (NOACs) needs to be further explored in future studies.

Warfarin dosing strategies evolution and its progress in the era of precision medicine, a narrative review

Background For decades, vitamin K antagonists and specifically warfarin, have been the sole agents used orally to manage thromboembolic conditions, including stroke and venous thromboembolism (VTE). Several factors lead to warfarin dose variability, including genetic and non-genetic factors which made warfarin management challenging especially at the initiation phase. To overcome the challenges with warfarin dosing at initiation, strategies other than conventional or fixed dosing were introduced and explored. Aim In this narrative review, we aim to discuss and critique the different dosing strategies for warfarin at initiation with more focus on genotype-guided warfarin dosing and the most recent supporting evidence for and against its use. Method Medline database was searched from 1965 to July 2021. Articles addressing different warfarin dosing methods were screened for inclusion. Results A number of methods exist for warfarin initiation. Studies comparing different dosing methods for initiation yielded conflicting outcomes due to differences in study design, population studied, comparator, and outcomes measured. Conclusions Looking at the big picture, the use of genetic dosing for warfarin initiation can lead to better outcomes. Whether these better outcomes are clinically or economically beneficial remains controversial.

Comparison of 3-factor versus 4-factor prothrombin complex concentrate for emergent warfarin reversal: a systematic review and meta-analysis

Background

Patients requiring emergent warfarin reversal (EWR) have been prescribed three-factor prothrombin complex concentrate (PCC3) and four-factor prothrombin complex concentrate (PCC4) to reverse the anticoagulant effects of warfarin. There is no existing systematic review and meta-analysis of studies directly comparing PCC3 and PCC4.

Methods

The primary objective of this systematic review and meta-analysis was to determine the effectiveness of achieving study defined target INR goal after PCC3 or PCC4 administration. Secondary objectives were to determine the difference in safety endpoints, thromboembolic events (TE), and survival during the patients’ hospital stay. Random-effects meta-analysis models were used to estimate the odds ratios (OR), and heterogeneity associated with the outcomes. The Newcastle-Ottawa Scale was used to assess study quality, and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed.

Results

Ten full-text manuscripts and five abstracts provided data for the primary and secondary outcomes. Patients requiring EWR had more than three times the odds of reversal to goal INR when they were given PCC4 compared to PCC3 (OR = 3.61, 95% CI: 1.97–6.60, p < 0.001). There was no meaningful clinical association or statistically significant result between PCC4 and PCC3 groups in TE (OR = 1.56, 95% CI: 0.83–2.91, p = 0.17), or survival during hospital stay (OR = 1.34, 95% CI: 0.81–2.23, p = 0.25).

Conclusion

PCC4 is more effective than PCC3 in meeting specific predefined INR goals and has similar safety profiles in patients requiring emergent reversal of the anticoagulant effects of warfarin.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12873-022-00568-x.

Methods to Correct Drug-Induced Coagulopathy in Bleeding Emergencies: A Comparative Review

OBJECTIVE

Anticoagulant and antiplatelet therapy have become increasingly popular. The goal of therapy is to prevent venous thromboembolism and platelet aggregation, respectively. Traditional anticoagulant and antiplatelet drugs are quickly being replaced with novel medications with more predictable pharmacokinetics. Unfortunately, these drugs carry the risk of uncontrolled hemorrhage because of drug-induced coagulopathy. Uncontrolled hemorrhage continues to be a major cause of preventable death: hemorrhage accounts for approximately 30% of trauma-related deaths, second to brain injury. Controlling hemorrhage while dealing with comorbidities remains a challenge to clinicians. There are many gaps in care and knowledge that contribute to the struggle of treating this patient population.

METHODS

This literature review is focused on the most effective ways to achieve hemostasis in a patient with drug-induced coagulopathy. The antiplatelet therapies aspirin, clopidogrel, ticlopidine, pasugrel, and ticagrelor are analyzed. Anticoagulant therapies are also reviewed, including warfarin, rivaroxaban, apixaban, edoxaban, and dabigatran. In addition, viscoelastic testing and platelet function assays are reviewed for their ability to monitor drug effectiveness and to accurately depict the patient's ability to clot. This review focuses on articles from the past 10 years. However, there are limitations to the 10-year restriction, including no new research posted within the 10-year timeline on particular subjects. The most recent article was then used where current literature did not exist (within 10 years).

RESULTS

Traditional anticoagulants have unpredictable pharmacokinetics and can be difficult to correct in bleeding emergencies. Vitamin K has been proven to reliably and effectively reverse the effect of vitamin K antagonists (VKAs) while having a lower anaphylactoid risk than frozen plasma. Prothrombin complex concentrates should be used when there is risk of loss of life or limb. Frozen plasma is not recommended as a first-line treatment for the reversal of VKAs. Novel anticoagulants have specific reversal agents such as idarucizumab for dabigatran and andexxa alfa for factor Xa (FXa) inhibitors. Although reliable, these drugs carry a large price tag. As with traditional anticoagulants, cheaper alternative therapies are available such as prothrombin complex concentrates. Finally, static coagulation testing works well for routine therapeutic drug monitoring but may not be appropriate during bleeding emergencies. Viscoelastic testing such as thromboelastography and rotational thromboelastometry depict in vivo hemostatic properties more accurately than static coagulation assays. Adding viscoelastic testing into resuscitation protocols may guide blood product usage more efficiently.

CONCLUSION

This review is intended to be used as a guide. The topics covered in this review should be used as a reference for treating the conditions described. This review article also covers laboratory testing and is meant as a guide for physicians on best practices. These findings illustrate recommended testing and reversal techniques based off evidence-based medicine and literature.

The VKORC1 and CYP2C9 gene variants as pharmacogenetic factors in acenocoumarol therapy in Serbian patients - consideration of hypersensitivity and resistance

Introduction/Objective. Coumarin therapy represents one of the best models for applying pharmacogenetics. The contribution of factors influencing coumarin therapy can vary significantly between ethnic groups, which justifies conducting population-specific studies. The aim of this study was to analyze the influence of the most important genetic factors (VKORC1 and CYP2C9 genes) that affect coumarin therapy in patients from Serbia. Methods. A retrospective study involving 207 patients on acenocoumarol therapy was conducted. Genetic analyses were performed by direct sequencing. Influence on acenocoumarol dose of variants (VKORC1, CYP2C9*2, CYP2C9*3) causing hypersensitivity and VKORC1 variants causing resistance to acenocoumarol were analyzed. Multiple regression analysis was used to design a mathematical model for predicting individual drug dosage based on clinical-demographic and genetic data. Results. The study confirmed significant influence of the analyzed genetic factors on acenocoumarol maintenance dose. We designed mathematical model for predicting individual acenocoumarol dose and its unadjusted R2 was 61.8. In the testing cohort, our model gave R2 value of 42.6 and showed better prediction in comparison with model given by other authors. In the analyzed patients, nine different variants in the VKORC1 coding region were found. Among carriers of these variants 78% were completely resistant, and it was not possible to achieve therapeutic effect even with high doses of acenocoumarol. Conclusions. Population-specific model for prediction individual dose of acenocoumarol, may show advantages over protocols that are used in a generalized manner. Also, VKORC1 variants which cause coumarin resistance should be considered when planning therapy.

Increased Risk for Thromboembolism After Fontan Surgery: Considerations for Thromboprophylaxis

The Fontan circulation introduces an increased risk of thromboembolism which is associated with substantial mortality and morbidity. Adverse outcomes of thromboembolic complications post-Fontan surgery vary in both nature and severity, ranging from local tissue infarction and pulmonary embolism to Fontan failure and ischemic stroke. Furthermore, recent studies have identified that subclinical stroke is common yet underdiagnosed in Fontan patients. Fontan patients are commonly treated with antiplatelet agents and/or anticoagulants as primary thromboprophylaxis. Optimal thromboprophylaxis management in the Fontan population is still unclear, and clinical consensus remains elusive despite the growing literature on the subject. This perspective will describe the nature of thromboembolism post-Fontan surgery and provide evidence for the use of both current and emerging thromboprophylaxis options for children and adults living with Fontan circulation.

Budget impact analysis of a bioprosthetic valve with a novel tissue versus mechanical aortic valve replacement in patients older than 65 years with aortic stenosis in Saudi Arabia

AIMS

A budget impact analysis (BIA) comparing bioprosthetic valves with RESILIA tissue and mechanical valves in aortic stenosis (AS) patients > 65 years in the public and private sectors of Saudi Arabia.

MATERIALS AND METHODS

A decision-tree with a partitioned survival model was adapted to estimate the financial consequences of either a RESILIA tissue valve or a mechanical valve in aortic valve replacement (AVR) procedures up to 5 years. The budget impact of resource consumption for both valve types was compared and included disabling strokes, reoperations, minor thromboembolic events, major bleeding, endocarditis, anticoagulation treatment and monitoring, and echocardiogram assessments. One-way sensitivity analyses (OWSA) were performed on cost and probability inputs.

RESULTS

RESILIA tissue valves versus mechanical valves are overall budget saving commencing in Year 1 and savings gradually increase year-on-year. The higher costs of the initial procedure, reoperation, and additional monitoring (echocardiogram tests and visits) associated with RESILIA tissue valves are offset by savings in warfarin use, disabling strokes, major bleeding, and anticoagulation complications. The cost per initial procedure per patient is SAR795 higher for a RESILIA tissue valve reflecting the higher valve acquisition cost, which is partially offset by a shorter hospital stay. The OWSA suggests that total procedure costs of each valve, including the hospital stay, are the main cost drivers in the model.

LIMITATIONS

The variability of cost inputs and the presence of multiple payers with multiple costing data is a key challenge in Saudi Arabia. Budget impact results may, therefore, change if repeated per AVR center and may also be impacted by the long-term durability of RESILIA tissue valves.

CONCLUSIONS

An AVR in patients > 65 years with a RESILIA tissue valve is budget-saving from the first year in Saudi Arabia. Patients, payers, providers and policymakers may benefit economically from increased implantation of RESILIA tissue valves.

Severe Bleeding Risks of Direct Oral Anticoagulants in the Prevention and Treatment of Venous Thromboembolism: A Network Meta-Analysis of Randomised Controlled Trials

OBJECTIVE

The aim of this study was to determine the severe bleeding safety of direct oral anticoagulants (DOACs) for the prevention and treatment of venous thromboembolism (VTE).

METHODS

PubMed, EMBASE, Web of Science, and the Cochrane Library databases were searched up to 6 January 2021. The incidence of severe bleeding (major, gastrointestinal [GI], intracranial, and fatal) was investigated. Using frequentist network meta-analysis, interventions that were not compared directly could be compared indirectly by the 95% confidence interval (CI), making the search results more intuitive. Based on surface under the cumulative ranking curves (SUCRA), the relative ranking probability of each group was generated.

RESULTS

Thirty-one randomised controlled trials (76 641 patients) were included. For the treatment of VTE, the risk of major bleeding with apixaban was significantly lower than dabigatran (odds ratio [OR] 2.10, 95% CI 1.07 - 4.12) and edoxaban (OR 2.64, 95% CI 1.36 - 5.15). The safety of the drugs was ranked from highest to lowest as follows: major bleeding: apixaban (SUCRA 98.0), rivaroxaban (SUCRA 69.6), dabigatran (SUCRA 50.7), edoxaban (SUCRA 26.5), and vitamin K antagonists (VKAs; SUCRA 5.1); GI bleeding: apixaban (SUCRA 80.7), rivaroxaban (SUCRA 66.8), edoxaban (SUCRA 62.3), VKAs (SUCRA 34.4), and dabigatran (SUCRA 5.8); intracranial bleeding: rivaroxaban (SUCRA 74.4), edoxaban (SUCRA 70.4), dabigatran (SUCRA 58.2), apixaban (SUCRA 44.4), and VKAs (SUCRA 5.6); fatal bleeding: edoxaban (SUCRA 82.7), rivaroxaban (SUCRA 59.2), dabigatran (SUCRA 48.6), apixaban (SUCRA 43.0), and VKAs (SUCRA 16.3). For the prevention of VTE, the risk of major bleeding with apixaban was significantly lower than rivaroxaban (OR 2.14, 95% CI 1.02 - 4.52). Among the four types of bleeding, apixaban had the lowest bleeding risk among DOACs (major bleeding: SUCRA 81.6; GI bleeding: SUCRA 75.4; intracranial bleeding: SUCRA 64.1; fatal bleeding: SUCRA 73.6).

CONCLUSIONS

For the treatment of VTE, in terms of major bleeding and GI bleeding, apixaban had the lowest bleeding risk; in terms of intracranial bleeding, rivaroxaban had the lowest bleeding risk; in terms of fatal bleeding, edoxaban had the lowest bleeding risk. For the prevention of VTE, apixaban had the lowest bleeding risk.

Management of Coagulopathy in Bleeding Patients

Early recognition of coagulopathy is necessary for its prompt correction and successful management. Novel approaches, such as point-of-care testing (POC) and administration of coagulation factor concentrates (CFCs), aim to tailor the haemostatic therapy to each patient and thus reduce the risks of over- or under-transfusion. CFCs are an effective alternative to ratio-based transfusion therapies for the correction of different types of coagulopathies. In case of major bleeding or urgent surgery in patients treated with vitamin K antagonist anticoagulants, prothrombin complex concentrate (PCC) can effectively reverse the effects of the anticoagulant drug. Evidence for PCC effectiveness in the treatment of direct oral anticoagulants-associated bleeding is also increasing and PCC is recommended in guidelines as an alternative to specific reversal agents. In trauma-induced coagulopathy, fibrinogen concentrate is the preferred first-line treatment for hypofibrinogenaemia. Goal-directed coagulation management algorithms based on POC results provide guidance on how to adjust the treatment to the needs of the patient. When POC is not available, concentrate-based management can be guided by other parameters, such as blood gas analysis, thus providing an important alternative. Overall, tailored haemostatic therapies offer a more targeted approach to increase the concentration of coagulation factors in bleeding patients than traditional transfusion protocols.

Factors associated with bleeding complications in hernia repair of warfarin users

OBJECTIVE

In this retrospective study, we aimed to determine factors associated with bleeding complications in patients on long-term warfarin, undergoing inguinal hernia repair using low-molecular-weight heparin (LMWH) bridging.

METHODS

Two-year hospital records yielded 44 inguinal hernia repair patients on long-term warfarin (26 men, 4 women, aged 57.4 [38-72] years). All patients were managed with LMWH bridging. Patient and operative characteristics, LMWH bridging characteristics, and international normalized ratio (INR) values were compared between patients with and without postoperative bleeding complications.

RESULTS

Indication for warfarin use was heart valve disease (n=15), atrial fibrillation (n=7), deep venous thrombosis (n=3), cerebrovascular event (n=3), and pulmonary embolism (n=2). Four of the operations were urgent, while the remaining were elective. There were four ecchymosis cases and three hematoma cases in a total of seven patients. Baseline (2.94±0.26 versus 2.16±0.38, p<0.001) and preoperative INR values (1.69±0.67 versus 1.31±0.35, p=0.027) were significantly higher, while postoperative INR values (1.04±0.09 versus 1.2±0.13, p=0.004) were significantly lower in patients having bleeding complications.

CONCLUSIONS

Baseline, preoperative INR, and postoperative INR were the only variables associated with postoperative bleeding complications in patients undergoing LMWH-bridged inguinal hernia repair. We suggest close monitoring of INR levels in long-term warfarin users, even for relatively low-bleeding risk operations such as inguinal hernia repair.

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.

Direct oral anticoagulants versus warfarin in patients with single or double antibody-positive antiphospholipid syndrome

Warfarin is recognized as the standard treatment for thrombotic antiphospholipid syndrome (APS); however, direct oral anticoagulants (DOACs) represent appealing therapeutic alternatives given their lack of monitoring and limited drug interactions. A few randomized controlled trials comparing rivaroxaban with warfarin showed an increased risk of recurrent thromboembolism, specifically arterial thrombosis, in patients with high risk forms of APS such as those that are triple antibody positive. We conducted a single-center, retrospective cohort study of all patients within our health system from 2015 to 2020 with a diagnosis of APS (single or double antibody positive) and history of venous thromboembolism. We sought to compare the proportion of patients with a recurrent thrombosis when prescribed a DOAC versus warfarin. Among 96 patients included, 57 were prescribed warfarin and 39 were prescribed a DOAC (90% rivaroxaban). The proportion of patients with a recurrent thromboembolism was almost three times higher in the DOAC group (15.4%) compared to the warfarin group (5.3%), although this was not statistically significant (p = 0.15). Major bleeding was not different between groups. Our findings suggest that rivaroxaban may pose an increased risk for recurrent thromboembolism in low risk APS patients that are single or double-antibody positive compared to warfarin. Results of our study should be cautiously applied to DOACs besides rivaroxaban given their small representation in this study.

Does Platelet-Rich Fibrin Prevent Hemorrhagic Complications After Dental Extractions in Patients Using Oral Anticoagulant Therapy?

PURPOSE

The number of anticoagulated patients requiring dental extractions and other minor dentoalveolar surgical procedures has increased significantly. The purpose of this study was to determine whether the use of platelet-rich fibrin (PRF) prevents hemorrhagic complications after dental extractions in patients being treated with oral anticoagulants.

METHODS

A 2-phase PROSPERO-registered systematic review of published within-subject controlled trials (CRD42020186678) was conducted in accordance with the PRISMA statement. Searches were conducted through Medline via PubMed, Web of Science, LILACS, Central Cochrane, Scopus, DOSS, and Google Scholar, until May 2020. The predictor variable was the study group (PRF vs use/non-use of other hemostatic agents). The main outcome of interest was the risk of bleeding after tooth extraction and the covariates were postoperative complications. Data analysis included synthesis of results, risk of bias (RoB) evaluation, meta-analysis (random effects; I²-based heterogeneity; 95% confidence), and certainty of evidence assessment.

RESULTS

From a total of 216 articles, 3 articles (low-moderate RoB) were included for evaluation in this systematic review and meta-analysis. A total of 130 patients were involved. The outcomes of the meta-analysis showed that the use of PRF in extraction wounds did not reduce the risk of bleeding after extraction in anticoagulated patients (P= .330; I² = 99%). Furthermore, the use of PRF did not improve pain scores (P = .470; I² = 96%) or the risk of postoperative alveolitis (P = .4300; I² = 38%) in anticoagulated patients. The certainty of the evidence ranged from moderate to low.

CONCLUSIONS

The findings of this systematic review and meta-analysis suggest that PRF does not prevent hemorrhagic complications after tooth extraction in patients using oral anticoagulant therapy.

A meta-analysis of andexanet alfa and prothrombin complex concentrate in the treatment of factor Xa inhibitor-related major bleeding

Background

Andexanet alfa (andexanet) and prothrombin complex concentrate (PCC) are both reversal agents for major bleeding in patients using factor Xa inhibitors (FXaIs). Our aim was to evaluate the current evidence for the effectiveness and safety of andexanet and PCC in a systematic review and meta-analysis.

Objectives

Primary objective was hemostatic effectiveness. Secondary objectives were thromboembolic event rate and mortality.

Methods

A systematic review was performed in PubMed and Embase. Studies describing the effectiveness and/or safety of PCC or andexanet in patients with major bleeding using FXaIs were included. Meta-analysis was performed using a random-effects model.

Results

Seventeen PCC studies, 3 andexanet studies, and 1 study describing PCC and andexanet were included, comprising 1428 PCC-treated and 396 andexanet-treated patients. None of the included studies had control groups, hampering a pooled meta-analysis to compare the two reversal agents. Separate analyses for andexanet and PCC were performed. In subgroup analysis, the pooled proportion of patients with effective hemostasis in studies that used Annexa-4 criteria demonstrated a hemostatic effectiveness of 0.85 (95% confidence interval [CI], 0.80-0.90) in PCC and 0.82 (95% CI, 0.78-0.87) in andexanet studies. The pooled proportion of patients with thromboembolic events was 0.03 (95% CI, 0.02-0.04) in PCC and 0.11 (95% CI, 0.04-0.18) in andexanet studies.

Conclusion

Based on the available evidence with low certainty from observational studies, PCC and andexanet demonstrated a similar, effective hemostasis in the treatment of major bleeding in patients using FXaIs. Compared to PCC, the thromboembolic event rate appeared higher in andexanet-treated patients.

Pharmacometric modeling to explore 4F-PCC dosing strategies for VKA reversal in patients with INR below 2

The indicated dose of 4-factor prothrombin complex concentrate (4F-PCC) for urgent vitamin K antagonist (VKA) reversal in patients with an international normalized ratio (INR) of 2 to 4 is 25 IU/kg, but there is no indicated dose for INR <2. We explored 4F-PCC dosing strategies for baseline INR <2. Clinical trial data were used to develop pharmacometric models for Factor X (FX) and FII, accounting for covariates including baseline INR. FX and FII levels over time were simulated for mean baseline INR levels of the clinical trial participants plus baseline INRs 3.1, 1.9, and 1.6. For each INR, 200 virtual male patients were simulated to evaluate 4F-PCC doses of 35, 25, 20, 15, 12.5, and 10 IU/kg. Given an elevated bleeding risk with VKA therapy in Japanese vs Western populations, results were stratified by Japanese and non-Japanese patients. Target levels of FX and FII were ≥50% activity at 30 minutes after dosing in ≥80% of patients. FX- and FII-time models were developed with 1088 FX observations from 193 patients and 1074 FII observations from 192 patients. Model-based simulations indicated that at baseline INR 3.1, ≥80% of patients achieved ≥50% FX and FII activity with 25 IU/kg and 20 IU/kg 4F-PCC, respectively; at baseline INR 1.9, corresponding doses were 20 IU/kg and 15 IU/kg 4F-PCC, and at baseline INR 1.6, corresponding doses were 15 IU/kg, and 10 IU/kg 4F-PCC. Trends in Japanese and non-Japanese patients were similar. In conclusion, low 4F-PCC doses (15-20 IU/kg) may be sufficient to achieve hemostatic levels of FX and FII in Japanese and non-Japanese patients with baseline INR <2.

Evaluation of fixed versus variable dosing of 4-factor prothrombin complex concentrate for emergent warfarin reversal

STUDY OBJECTIVE

This study compares the safety and efficacy of a fixed dose of 4-factor prothrombin complex concentrate (4FPCC) to the FDA-approved variable dosing for reversal of warfarin-induced anticoagulation.

METHODS

This was a single-center, prospective, open-label, randomized controlled trial with subjects randomized to 4FPCC at a fixed dose of 1500 IU or the FDA-approved variable dosing regimen. The primary efficacy outcome (reversal success) was defined as a post-intervention international normalized ratio (INR) of less than or equal to 1.5. Given that 4FPCC is the standard of care for reversal of warfarin-induced anticoagulation an active-controlled approach was employed with the two dosing regimens compared based on efficacy, cost, and safety outcomes.

RESULTS

71 subjects (34 in the fixed dose group and 37 in the variable dose group) completed the study. There were no significant differences in age, gender, weight, initial INR, or indication for 4FPCC administration between the two treatment groups. Reversal success in the fixed-dose group was 61.8%, while in the variable dose group reversal success was 89.2%. Reversal success in the fixed-dose group was significantly lower than the rate of reversal success in the variable dose group (27.4% lower, p = 0.011).

CONCLUSION

The results of this study provide evidence that fixed dosing results in lower reversal success rates as compared to variable dosing of 4FPCC for warfarin-induced anticoagulation.

Drug-drug interactions between vitamin K antagonists and statins: a systematic review

PURPOSE

Concomitant use of vitamin K antagonists (VKA) and statins is frequent in cardiovascular patients. However, clinical guidelines on this drug combination are divergent. Therefore, we performed a systematic review to evaluate the effect of statin initiation on coagulation among VKA users.

METHODS

Following the PRISMA guidelines, we applied two broad search strategies for the drug interaction between VKA and statins in both Embase and Pubmed; 8623 unique hits were obtained. In the final sample, eight studies were included.

RESULTS

The most frequently used VKA in the studies was warfarin, while simvastatin was the most commonly initiated statin. All included studies showed a minor increase in the anticoagulant effect of VKA following statin initiation during VKA treatment. The reported increases in mean international normalized ratio (INR) ranged from 0.15-0.65.

CONCLUSION

The anticoagulant effect of statin initiation in patients treated with VKA is likely to be of limited clinical relevance but should be evaluated individually.

Monitoring of anticoagulation in thrombotic antiphospholipid syndrome

Anticoagulation is central to the management of thrombotic antiphospholipid syndrome (APS). The standard anticoagulant treatment for thrombotic APS is life-long warfarin or an alternative vitamin K antagonist. The role of direct oral anticoagulants for thrombotic APS is not established due to the lack of definitive evidence and has recently been addressed in international guidance. Other anticoagulant options include low molecular weight heparin, unfractionated heparin, and fondaparinux. In APS patients, lupus anticoagulant can affect phospholipid-dependent coagulation monitoring tests, so that they may not reflect true anticoagulation intensity. Accurate assessment of anticoagulation intensity is essential, to optimize anticoagulant dosing and facilitate thrombus resolution; minimize the risk of recurrent thrombosis or bleeding; inform assessment of whether recurrent thrombosis is related to breakthrough thrombosis while on therapeutic anticoagulation, subtherapeutic anticoagulation, non-adherence, or spurious results; and guide the management of bleeding. Knowledge of anticoagulant intensity also informs assessment and comparison of anticoagulation regimens in clinical studies. Considerations regarding anticoagulation dosing and/or monitoring of thrombotic APS patients underpin appropriate management in special situations, notably APS-related severe renal impairment, which can occur in APS or APS/systemic lupus erythematosus-related nephropathy or catastrophic APS; and APS-related thrombocytopenia. Anticoagulant dosing and monitoring in thrombotic APS patients also require consideration in anticoagulant-refractory APS and during pregnancy. In this review, we summarize the tests generally used in monitoring anticoagulant therapy, use of the main anticoagulants considered for thrombotic APS, lupus anticoagulant effects on anticoagulation monitoring tests, and strategies for appropriate anticoagulant monitoring in thrombotic APS.

Updated recommendations for the treatment of venous thromboembolism

Venous thromboembolism (VTE), which includes pulmonary embolism and deep vein thrombosis, is a condition characterized by abnormal blood clot formation in the pulmonary arteries and the deep venous vasculature. It is often serious and sometimes even fatal if not promptly and appropriately treated. Moreover, the later consequences of VTE may result in reduced quality of life. The treatment of VTE depends on various factors, including the type, cause, and patient comorbidities. Furthermore, bleeding may occur as a side effect of VTE treatment. Thus, it is necessary to carefully weigh the benefits versus the risks of VTE treatment and to actively monitor patients undergoing treatment. Asian populations are known to have lower VTE incidences than Western populations, but recent studies have shown an increase in the incidence of VTE in Asia. A variety of treatment options are currently available owing to the introduction of direct oral anticoagulants. The current VTE treatment recommendation is based on evidence from previous studies, but it should be applied with careful consideration of the racial, genetic, and social characteristics in the Korean population.