Vitamin K antagonist use: evidence of the difficulty of achieving and maintaining target INR range and subsequent consequences

Effect of a 3-Month Single-Drug Approach Using Rivaroxaban for Symptomatic Proximal Deep Vein Thrombosis

Background: Factor Xa inhibitors, such as rivaroxaban, are increasing the convenience of treatment for deep vein thrombosis (DVT). Limited evidence exists regarding clot evaluation at 3 months after treatment for DVT. Methods and Results: We retrospectively analyzed the clinical course of symptomatic proximal DVT in patients who received 3 months of anticoagulation treatment at our hospital. Patients treated with the rivaroxaban single-drug approach were classified as group A (n=42). Patients treated with unfractionated heparin (UFH) or subcutaneous fondaparinux followed by vitamin K antagonist comprised group B (n=60) as an historical cohort. The quantitative ultrasound thrombosis (QUT) score was used to quantify clot burden before and after treatment. No significant differences were observed in patient characteristics between the groups. Serum D-dimer levels in both groups significantly improved after treatment. Clot volume assessed using QUT also reduced significantly in both groups. The QUT score in groups A and B improved from 7.5 [4.8, 12.0] to 3.0 [1.8, 5.0; P=0.000] and 7.0 [4.0, 9.8] to 3.0 [2.0, 5.0; P=0.000], respectively. The change in QUT (∆QUT) was significantly greater in group A compared with group B (-4.5 [-8.25, -2.0] vs. -2.0 [-6.0, 0.0]; P=0.005). Conclusions: We were able to demonstrate the effectiveness of DVT treatment using rivaroxaban over a period of 3 months from onset, in terms of clot regression evaluated using the QUT score.

Vitamin K1 intake is associated with lower risk for all-cause and cardiovascular disease mortality in community-dwelling older Australian women

BACKGROUND AND AIMS

Assessing the relationship between vitamin K1 intakes, using region-specific food databases, with both all-cause, and cardiovascular disease (CVD) mortality warrants further investigation to inform future preventative strategies. Consequently, we examined the aforementioned associations in the Perth Longitudinal Study of Ageing Women (PLSAW).

METHODS AND RESULTS

1436 community-dwelling older Australian women (mean ± SD age 75.2 ± 2.7 years) completed a validated food frequency questionnaire at baseline (1998). Vitamin K1 intake was calculated based on an Australian vitamin K food database, supplemented with published data. All-cause and CVD mortality data was obtained from linked health records. Associations were examined using restricted cubic splines within Cox-proportional hazard models, adjusted for a range of cardiovascular and lifestyle related risk factors. Over 15 years of follow-up, 601 (41.9%) women died, with 236 deaths (16.4%) due to CVD. Compared to women with the lowest vitamin K1 intakes (Quartile 1, median 49.1 μg/day), those with the highest intakes (Quartile 4, median 119.3 μg/day) had lower relative hazards for all-cause mortality (HR 0.66 95%CI 0.51-0.86) and CVD mortality (HR 0.61 95%CI 0.41-0.92). A plateau in the inverse association was observed from vitamin K1 intakes of approximately ≥80 μg/day.

CONCLUSION

Higher vitamin K1 intakes were associated with lower risk for both all-cause and CVD mortality in community-dwelling older women, independent of CVD related risk factors. A higher intake of vitamin K1 rich foods, such as leafy green vegetables, may support cardiovascular health.

Small bowel intramural hematoma caused by warfarin: case report and literature review

BACKGROUND

Intramural hematoma of the small bowel is a rare yet acute gastrointestinal condition typically linked with impaired coagulation function, often posing diagnostic challenges. It is principally encountered in patients undergoing prolonged anticoagulant therapy, specifically warfarin.

CASE PRESENTATION

We reported a case of intramural hematoma associated with warfarin use. The patient was admitted to hospital with abdominal pain and had received anticoagulant therapy with warfarin 2.5 mg/day for 4 years. Laboratory examination showed decreased coagulation function, abdominal CT showed obvious thickening and swelling of part of the jejunal wall, and abdominal puncture found no gastroenteric fluid or purulent fluid. We treated the patient with vitamin K and fresh frozen plasma. The patient was discharged after the recovery of coagulation function. Then we undertaook a comprehensive review of relevant case reports to extract shared clinical features and effective therapeutic strategies.

CONCLUSION

Our analysis highlights that hematoma in the small intestinal wall caused by warfarin overdose often presents as sudden and intense abdominal pain, laboratory tests suggest reduced coagulation capacity, and imaging often shows thickening of the intestinal wall. Intravenous vitamin K and plasma supplementation are effective non-surgical strategies. Nevertheless, in instances of severe obstruction and unresponsive hemostasis, surgical resection of necrotic intestinal segments may be necessary. In the cases we reported, we avoided surgery by closely monitoring the coagulation function. Therefore, we suggest that identifying and correcting the impaired coagulation status of patient is essential for timely and appropriate treatment.

Maxillofacial haemorrhagic symptoms in emergency department patients: impact of antithrombotics

PURPOSE

To investigate the effect of antithrombotics on the occurrence of maxillofacial haemorrhagic symptoms, and to determine if these haemorrhagic symptoms are predictors of maxillofacial fractures.

METHOD

A prospective cohort study was conducted of consecutive patients with maxillofacial trauma who had been admitted to the emergency department of four hospitals in the Netherlands. This study compared five haemorrhagic symptoms (peri-orbital haematoma, raccoon eyes, epistaxis, subconjunctival ecchymosis, and intra-oral haematoma) between patients not-using (NUA) and using (UA) of antithrombotics, and whether these maxillofacial haemorrhagic symptoms served as predictors for maxillofacial fractures.

RESULTS

Out of the 1005 patients, 812 (81%) belonged to the NUA group, and 193 (19%) to the UA group. UA patients exhibited higher frequencies of peri-orbital hematoma (54% vs. 39%, p < 0.001), raccoon eyes (10% vs. 5%, p = 0.01), and subconjunctival ecchymoses (16% vs. 7%, p < 0.001). In NUA, peri-orbital hematoma (OR = 2.5, p < 0.001), epistaxis (OR = 4.1, p < 0.001), subconjunctival ecchymosis (OR = 2.3, p = 0.02), and intra-oral hematoma (OR = 7.1, p < 0.001) were significant fracture predictors. Among UA, peri-orbital hematoma (OR = 2.2, p = 0.04), epistaxis (OR = 5.4, p < 0.001), subconjunctival ecchymosis (OR = 3.7, p = 0.008), and intra-oral hematoma (OR = 22.0, p < 0.001) were significant fracture predictors.

CONCLUSION

Maxillofacial haemorrhagic symptoms were observed more frequently in the UA group than in the NUA group. However, in both groups, maxillofacial haemorrhagic symptoms appear to be predictors of maxillofacial fractures. Caution is warranted in attributing these symptoms solely to antithrombotic use during emergency department assessments.

Electrochemical Monitoring in Anticoagulation Therapy

The process of blood coagulation, wherein circulating blood transforms into a clot in response to an internal or external injury, is a critical physiological mechanism. Monitoring this coagulation process is vital to ensure that blood clotting neither occurs too rapidly nor too slowly. Anticoagulants, a category of medications designed to prevent and treat blood clots, require meticulous monitoring to optimise dosage, enhance clinical outcomes, and minimise adverse effects. This review article delves into the various stages of blood coagulation, explores commonly used anticoagulants and their targets within the coagulation enzyme system, and emphasises the electrochemical methods employed in anticoagulant testing. Electrochemical sensors for anticoagulant monitoring are categorised into two types. The first type focuses on assays measuring thrombin activity via electrochemical techniques. The second type involves modified electrode surfaces that either directly measure the redox behaviours of anticoagulants or monitor the responses of standard redox probes in the presence of these drugs. This review comprehensively lists different electrode compositions and their detection and quantification limits. Additionally, it discusses the potential of employing a universal calibration plot to replace individual drug-specific calibrations. The presented insights are anticipated to significantly contribute to the sensor community's efforts in this field.

The impact of anticoagulation therapy on kidney function in patients with atrial fibrillation and chronic kidney disease

INTRODUCTION

Atrial fibrillation (AF) and chronic kidney disease (CKD) are closely related. These diseases share common risk factors and are associated with increased risk of thromboembolic events. Choosing the appropriate oral anticoagulant therapy (OAC) in patients with AF and CKD is challenging. Deterioration of renal function is common in patients with AF treated with OACs, although not all OACs affect the kidneys equally.

AREAS COVERED

In this review, we aim to summarize the current knowledge of the prevention of thromboembolic events in patients with AF and CKD, focusing on the impact of specific OAC agents on renal function.

EXPERT OPINION

Consideration of OAC use is mandatory in patients with AF and CKD who are at increased risk of stroke or systemic embolism. Available evidence suggests that the use of non-vitamin K antagonist oral anticoagulants (NOACs) is associated with slower deterioration of renal function in comparison to Vitamin K antagonists (VKAs). Hence, a NOAC should be used in preference to VKAs in all NOAC-eligible patients with AF and CKD. Regarding patients with end-stage renal dysfunction and those on dialysis or renal replacement therapy, the use of NOAC should be considered in line with locally relevant formal recommendations.

Oral Anticoagulants after Heart Transplantation-Comparison between Vitamin K Antagonists and Direct Oral Anticoagulants

AIMS

Patients after heart transplantation (HTX) often require oral anticoagulants (OACs) due to atrial arrhythmias or thromboembolic events but little is known about the post-transplant use of direct oral anticoagulants (DOACs). We investigated the frequency, indications, and complications of DOACs and vitamin K antagonists (VKAs) after HTX.

METHODS

We screened all adult patients for the use of post-transplant OACs who underwent HTX at Heidelberg Heart Center between 2000 and 2021. Patients were stratified by type of OAC (DOAC or VKA) and by DOAC agents (apixaban, dabigatran, edoxaban, or rivaroxaban). Indications for OACs comprised atrial fibrillation, atrial flutter, pulmonary embolism, upper and lower extremity deep vein thrombosis, as well as intracardiac thrombus.

RESULTS

A total of 115 of 459 HTX recipients (25.1%) required OACs, including 60 patients with DOACs (52.2%) and 55 patients with VKAs (47.8%). Concerning DOACs, 28 patients were treated with rivaroxaban (46.7%), 27 patients with apixaban (45.0%), and 5 patients with edoxaban (8.3%). We found no significant differences between both groups concerning demographics, immunosuppressive drugs, concomitant medications, indications for OACs, ischemic stroke, thromboembolic events, or OAC-related death. Patients with DOACs after HTX had a significantly lower one-year rate of overall bleeding complications (p = 0.002) and a significantly lower one-year rate of gastrointestinal hemorrhage (p = 0.011) compared to patients with VKAs after HTX in the Kaplan-Meier estimator.

CONCLUSIONS

DOACs were comparable to VKAs concerning the risk of ischemic stroke, thromboembolic events, or OAC-related death but were associated with significantly fewer bleeding complications in HTX recipients.

Role of factor VIII, IX, and XI in venous thrombosis recurrence risk in adults and children: A systematic review

Background

Predicting recurrent venous thromboembolic events (VTEs) is challenging in clinical practice for both adults and children, but it is relevant for clinical management. Identifying laboratory risk factors for VTE recurrence may aid in clinical decision-making.

Objective

The goal of this systematic review is to investigate the predictive role of FVIII, IX, or XI in recurrent VTE in adult and pediatric patients with a first VTE.

Methods

A systematic review of the published literature was conducted in databases MEDLINE In-Process, Other Nonindexed Citations, MEDLINE Epub Ahead of Print, EMBASE Classic + EMBASE (OvidSP), and Cochrane (Wiley). We included observational and interventional studies that comprised adults or children with a first VTE, FVIII, FIX, and/or FXI and objectively confirmed VTE recurrence. The quality in prognosis studies tool was used to assess the risk of bias.

Results

We identified 2177 unique studies, of which 19 were included (18 for adults and 1 for children). The risk of bias was overall low to moderate. The studies were heterogenous with regards to population (provoked/unprovoked primary VTE), exposure (type of assay and cut-off values), and statistical analysis results (measures of association and modeling strategy). In adults, contradictory evidence was found for FVIII and FXI as outcome predictors, while no research could establish if FIX predicts VTE recurrence. Data in pediatrics were limited. Given the extensive heterogeneity of the literature, a meta-analysis was not performed.

Conclusions

Overall, there is contradictory evidence that FVIII, FIX, or FXI predict recurrent VTE in adults and children. Addressing heterogeneity is a relevant aspect to consider in future studies investigating prognostic factors for VTE recurrence.

A Real-World Cost-Effectiveness Analysis of Rivaroxaban versus Vitamin K Antagonists for the Treatment of Symptomatic Venous Thromboembolism: Lessons from the REMOTEV Registry

Background and objectives: Venous thromboembolism (VTE) represents a health and economic burden with consequent healthcare resource utilization. Direct oral anticoagulants (DOACs) have emerged as the mainstay option for VTE treatment but few data exist on their cost-effectiveness as compared to the standard therapy (vitamin K antagonists (VKAs)). This study aimed to assess the cost-effectiveness of rivaroxaban compared to VKAs in VTE treatment by calculating the incremental cost effectiveness ratio (ICER). Materials and methods: We conducted a prospective observational study based on the REMOTEV registry, including patients hospitalized for VTE from 23 October 2013 to 31 July 2015, to evaluate the impact of the anticoagulant treatment (DOACs versus VKAs) on 6-month complications: major or clinically relevant non-major bleeding, VTE recurrence and all-cause death. Rivaroxaban was the only DOAC prescribed in this study. The ICER was calculated as the difference in costs divided by the difference in effectiveness. Results: Among the 373 patients included, 279 were treated with rivaroxaban (63.1 ± 17.9 years old; 49% men) and 94 with VKAs (71.3 ± 16.6 years old; 46% men). The mean cost was EUR 5662 [95% CI 6606; 9060] for rivaroxaban and EUR 7721 [95% CI 5130; 6304] for VKAs, while effectiveness was 0.0586 95% CI [0.0114; 0.126] for DOACs and 0.0638 [95% CI 0.0208; 0.109] for VKAs. The rivaroxaban treatment strategy was dominant with costs per patient EUR 2059 lower [95% CI -3582; -817] and a higher effectiveness of 0.00527 [95% CI -0.0606; 0.0761] compared to VKAs. Conclusions: This study provides real-world evidence that rivaroxaban is not only an efficient and safe alternative to VKAs for eligible VTE patients, but also cost-saving.

Predictive value of the Adjusted Global Anti-Phospholipid Syndrome Score on clinical recurrence in APS patients: A longitudinal study

OBJECTIVE

To assess the effect of the average adjusted global APS score (aGAPSS) over time on recurrence of clinical manifestations in APS patients through a retrospective longitudinal study.

METHODS

The study included 200 patients with APS. The aGAPSS was calculated for each patient at baseline and on a yearly basis for either up to 6 years (minimum 3 years) or just before the clinical event in patients who experienced clinical recurrence. The mean score per patient was computed. In patients under vitamin K antagonists (VKA) the percentage of time spent within the therapeutic range (TTR) was calculated. Cox-regression analysis was performed to determine the cut-off value of the aGAPSS with the strongest association with clinical recurrence.

RESULTS

Higher average aGAPSS values were found in patients who experienced clinical recurrence in comparison to patients who did not [8.81 (95% C.I. 7.53-10.08) vs 6.38 (95% C.I. 5.64-7.12), p = 0.001], patients with thrombotic recurrence compared to patients with obstetric recurrence [9.48 (95% C.I. 8.14-10.82) vs 4.25 (95% C.I. 0.85-7.65), p = 0.006], and patients with arterial thrombosis compared to patients with venous thrombosis [10.66 (S.D. 5.48) vs 6.63 (S.D. 4.42), p = 0.01]. aGAPSS values > 13 points were associated with the highest risk of recurrence in multivariate analysis [HR = 3.25 (95% C.I. 1.93-5.45, p < 0.0001]. TTR was not statistically different between patients who had thrombosis recurrence and patients who had not.

CONCLUSIONS

Our data support the role of periodic (annual) monitoring of the aGAPSS score in predicting clinical recurrence in patients with APS.

Direct oral anticoagulants versus warfarin in patients with antiphospholipid syndrome: A meta-analysis of randomized controlled trials

Objective

This study aimed to evaluate the efficacy and safety of direct oral anticoagulants (DOACs) versus warfarin in patients with antiphospholipid syndrome (APS).

Methods

We performed a literature search using MEDLINE, EMBASE, and the Cochrane Controlled Trials Register. We also performed a meta-analysis of randomized controlled trials (RCTs) investigating the effectiveness and safety of DOACs versus warfarin in patients with APS.

Results

Five RCTs involving 648 patients with APS (330 in DOAC-treated and 318 in control groups) were included in the meta-analysis. Among the patients included in the analysis, 29 (8.8%) patients experienced recurrent thrombosis in the DOAC treatment group, and 10 patients (3.1%) had thrombosis recurrence in the warfarin treatment group, resulting in a higher incidence in DOAC-treated than in the warfarin-treated groups [odds ratio (OR) = 2.163, 95% CI = 0.985–4.748, p = 0.055]. Incidence of arterial thrombosis was significantly higher in DOAC-treated patients than in warfarin-treated patients (OR = 5.168, 95% CI = 1.567–17.04, p = 0.007). Stroke and thrombosis occurrences were significantly higher in the triple positivity group than in the warfarin therapy group (OR = 12.03, 95% CI = 2.249–64.36, p = 0.004; OR = 2.940, 95% CI = 1.016–8.504, p = 0.047). However, venous thrombosis occurrences did not differ significantly between the DOAC-treated and warfarin-treated groups. There were no significant differences between the DOAC and warfarin groups in terms of any bleeding, major bleeding, minor bleeding, and all-cause mortality.

Conclusion

DOACs were associated with higher rates of arterial thrombosis than warfarin in patients with APS, especially in the triple-positive group. However, a higher risk of recurrent venous thrombosis was not found in APS patients treated with DOACs compared to those treated with warfarin.

Drug-Related Problems and Factors Involved in the Imbalance of Oral Anticoagulants in Lebanese Patients: A Cross-Sectional Study

The goal of this study was to identify drug-related problems (DRPs) and the factors involved in the imbalance of new oral anticoagulants (NOACs) and vitamin K antagonists in a Lebanese adult population with cardiovascular diseases. An imbalance in the hemostatic systems between procoagulant and anticoagulant factors in circulating blood produces either hemorrhagic or thrombotic conditions. A prospective cross-sectional study was conducted during 5 months in a teaching hospital. All patients at least 18 years of age taking oral anticoagulants were included in the study. A standardized questionnaire was used, and information was obtained from the patients’ profiles and electronic medical records. DRPs were identified and categorized according to the Pharmaceutical Care Network Europe classification system. A total of 258 patients were included. The overall prevalence of DRPs was 87.2%; the highest prevalence was observed in patients taking acenocoumarol (96.0%), in contrast to 76.7% and 59.0% in patients taking dabigatran and rivaroxaban, respectively. Drug interaction was the most frequent DRP (83.3%), followed by inappropriate monitoring (42.6%) and excessive dose (26.7%). Having renal disease, and taking proton-pump inhibitors or nonsteroidal anti-inflammatory drugs were among the factors affecting the international normalized ratio (INR) range (adjusted odds ratio [ORa] = 2.513, 95% confidence interval [CI] 1.238, 5.101; ORa = 2.487, 95% CI 1.139, 5.430 and ORa = 2.114, 95% CI 1.043, 4.286, respectively), whereas smoking and renal disease significantly affected activated partial thromboplastin time (aPTT) (ORa = 8.325, 95% CI 1.577, 43.965 and ORa = 6.922, 95% CI 1.471, 32.570, respectively). Patients taking NOACs had greater aPTT control and fewer DRPs, with a wide therapeutic index enabling administration of fixed doses.

The Immediate Effect of COVID-19 Vaccination on Anticoagulation Control in Patients Using Vitamin K Antagonists

Background  In January 2021, the Dutch vaccination program against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was started. Clinical studies have shown that systemic reactions occur in up to 50% of vaccine recipients. Therefore, COVID-19 vaccination could affect anticoagulation control, potentially leading to an increased risk of thrombotic events and bleeding complications.

Aims  This article investigates whether the BNT162b2 vaccine affects anticoagulation control in outpatients using vitamin K antagonists (VKAs).

Methods  A case-crossover study was performed in a cohort of outpatient VKA users from four Dutch anticoagulation clinics who received a BNT162b2 vaccine. International normalized ratio (INR) results and VKA dosages before the first vaccination, the reference period, were compared with those after the first and second vaccination.

Results  A total of 3,148 outpatient VKA users were included, with a mean age (standard deviation) of 86.7 (8.7) years, of whom 43.8% were male, 67.0% used acenocoumarol, and 33.0% phenprocoumon. We observed a decrease of 8.9% of INRs within range in the standard intensity group (target INR 2.0–3.0). There was both an increased risk of supratherapeutic (odds ratio [OR] = 1.34 [95% confidence interval [CI] 1.08–1.67]) and subtherapeutic levels (OR = 1.40 [95% CI 1.08–1.83]) after first vaccination. In the high-intensity group (target INR 2.5–3.5), the risk of a supratherapeutic INR was 2.3 times higher after first vaccination (OR = 2.29 [95% CI 1.22–4.28]) and 3.3 times higher after second vaccination (OR = 3.25 [95% CI 1.06–9.97]).

Conclusion  BNT162b2 was associated with an immediate negative effect on anticoagulation control in patients treated with VKAs, so it is advisable to monitor the INR shortly after vaccination, even in stable patients.

Pharmacologic Agents Used to Reverse the Anticoagulant Effect of Common Anticoagulants

Numerous oral and parenteral anticoagulant drugs are now available for clinical use. Understanding the precise pharmacologic properties of each anticoagulant is imperative for those practitioners who prescribe these drugs, including knowing the current recommendations for reversing the anticoagulant effect of each anticoagulant. This review provides a brief description of the various anticoagulants used today and also discusses the pharmacologic properties of those drugs used to reverse the anticoagulant action of specific anticoagulants.

Stability of vitamin K antagonist anticoagulation after COVID-19 diagnosis

BACKGROUND

Coagulopathy has been reported in severely ill patients with coronavirus disease 2019 (COVID-19). It is unclear whether outpatients with COVID-19 who are treated with vitamin K antagonists (VKAs) have unstable anticoagulation.

OBJECTIVE

To assess the stability of VKA therapy in patients with COVID-19 through a case-crossover study.

METHODS

Between February and July 2020, we included patients who tested positive for COVID-19 from two anticoagulant clinics in the Netherlands. We collected international normalized ratios (INRs) determined between 26 weeks before infection and 12 weeks after. Time in therapeutic range (TTR) and the variance growth rate (VGR) were calculated within patients.

RESULTS

Fifty-one patients with COVID-19 (mean age, 84 years) were included, of whom 15 (29%) were men. Mean TTR in the 26 weeks before COVID-19 was 80% (95% confidence interval [CI], 75-85) compared to 59% (95% CI, 51-68) in the 6 weeks after infection. Mean TTR difference was -23% (95% CI, -32 to -14) with a time above therapeutic range of 38% (95% CI, 30-47) in the 6 weeks after infection. The TTR rose again to 79% (95% CI, 69-89) between 6 and 12 weeks after infection. Also, VGR increased, with a mean increase of 4.8 (95% CI, 2.1-7.5) in the 6 weeks after infection. In the 26 weeks before infection, we registered 19 of 641 (3%) of INR ≥5.0 compared with 35 of 247 (14%) in the 6 weeks after (risk ratio, 4.4; 95% CI, 2.7-7.3).

CONCLUSIONS

COVID-19 is associated with a strong decrease in TTR and in therapeutic stability in patients taking VKAs. Additional monitoring in these patients is advised to maximize therapeutic stability.

Vitamin K in COVID-19—Potential Anti-COVID-19 Properties of Fermented Milk Fortified with Bee Honey as a Natural Source of Vitamin K and Probiotics

Vitamin K deficiency is evident in severe and fatal COVID-19 patients. It is associated with the cytokine storm, thrombotic complications, multiple organ damage, and high mortality, suggesting a key role of vitamin K in the pathology of COVID-19. To support this view, we summarized findings reported from machine learning studies, molecular simulation, and human studies on the association between vitamin K and SARS-CoV-2. We also investigated the literature for the association between vitamin K antagonists (VKA) and the prognosis of COVID-19. In addition, we speculated that fermented milk fortified with bee honey as a natural source of vitamin K and probiotics may protect against COVID-19 and its severity. The results reported by several studies emphasize vitamin K deficiency in COVID-19 and related complications. However, the literature on the role of VKA and other oral anticoagulants in COVID-19 is controversial: some studies report reductions in (intensive care unit admission, mechanical ventilation, and mortality), others report no effect on mortality, while some studies report higher mortality among patients on chronic oral anticoagulants, including VKA. Supplementing fermented milk with honey increases milk peptides, bacterial vitamin K production, and compounds that act as potent antioxidants: phenols, sulforaphane, and metabolites of lactobacilli. Lactobacilli are probiotic bacteria that are suggested to interfere with various aspects of COVID-19 infection ranging from receptor binding to metabolic pathways involved in disease prognosis. Thus, fermented milk that contains natural honey may be a dietary manipulation capable of correcting nutritional and immune deficiencies that predispose to and aggravate COVID-19. Empirical studies are warranted to investigate the benefits of these compounds.

Assessment of Outpatients' Knowledge and Adherence on Warfarin: The Impact of a Simple Educational Pamphlet

Warfarin is a critical medication that is broadly used for the treatment and prevention of thromboembolic disorders. Due to warfarin’s narrow therapeutic index, it is crucial that patients follow an appropriate dosage regimen. Patient knowledge is one of the most important factors to safe and effective use of warfarin. Due to the obvious risks of anticoagulants administration, evaluating patients’ awareness seems to be crucial. The purpose of this article was to evaluate the effects of intervention by an informative pamphlet on knowledge and adherence of patients who consumed warfarin. Two-hundred and fifty patients receiving warfarin were assigned to the study. They were asked to fill in the questionnaire. Then patients were provided with an educational pamphlet. In the second interview, patients filled the questionnaire again. Obtained data were assessed and analyzed by Excel software and SPSS version 18.0. Out of 250 patients who entered the study, 150 patients attended for the second interview. Data analysis revealed that out of 13 explanatory factors, only patients’ literacy level and income were the predictors which inversely correlated with the patients’ adherence (r = -0.44; p = 0.00040). Our educational intervention had a positive impact on patients’ knowledge regarding anticoagulation (p < 0.0001). Our findings revealed that a written informative pamphlet could effectively increase patients’ anticoagulation knowledge. Since, poorly literate patients had a lesser level of knowledge before and after educational intervention, it is recommended to develop appropriate educational programs especially designed for this group of patients.

Pharmacological Agents Targeting Thromboinflammation in COVID-19: Review and Implications for Future Research

Coronavirus disease 2019 (COVID-19), currently a worldwide pandemic, is a viral illness caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The suspected contribution of thrombotic events to morbidity and mortality in COVID-19 patients has prompted a search for novel potential options for preventing COVID-19-associated thrombotic disease. In this article by the Global COVID-19 Thrombosis Collaborative Group, we describe novel dosing approaches for commonly used antithrombotic agents (especially heparin-based regimens) and the potential use of less widely used antithrombotic drugs in the absence of confirmed thrombosis. Although these therapies may have direct antithrombotic effects, other mechanisms of action, including anti-inflammatory or antiviral effects, have been postulated. Based on survey results from this group of authors, we suggest research priorities for specific agents and subgroups of patients with COVID-19. Further, we review other agents, including immunomodulators, that may have antithrombotic properties. It is our hope that the present document will encourage and stimulate future prospective studies and randomized trials to study the safety, efficacy, and optimal use of these agents for prevention or management of thrombosis in COVID-19.

Dabigatran as an oral anticoagulant in patients with Budd-Chiari syndrome post-percutaneous endovascular intervention

BACKGROUND AND AIM

Anticoagulants play an important role in the management of Budd-Chiari syndrome. There is a paucity of data on the efficacy and safety of direct-acting oral anticoagulants-dabigatran, among patients with Budd-Chiari syndrome.

METHODS

In a retrospective analysis of prospectively maintained data, the stent patency rates, major bleeding episode, and a composite endpoint of major bleed and/or mortality rates were compared between Budd-Chiari syndrome patients treated with dabigatran (n = 36) or vitamin K antagonists (n = 62) following endovascular intervention.

RESULTS

The baseline characteristics, including sites of block and types of interventions, were similar between the two groups. The mean duration of follow-up in the dabigatran and vitamin K antagonist groups was 10.5 ± 6.7 and 14.1 ± 6.9 months (P = 0.006), respectively. The endovascular stent patency rates were comparable between the dabigatran and vitamin K antagonist groups at 6 months (91% vs 96.5%) and 12 months (91% vs 93%), P = 0.296 (log-rank test), respectively. Major bleeding events were comparable between the dabigatran and vitamin K antagonist groups at 6 months (3.5% vs 2%) and 12 months (3.5% vs 6.5%), P = 0.895 (log-rank test), respectively. The composite endpoint of mortality and major bleed was comparable between dabigatran and vitamin K antagonists at 6 months (4% vs 5%) and 12 months (4% vs 8%), P = 0.875 (log-rank test), respectively.

CONCLUSIONS

Dabigatran, as compared with vitamin K antagonists, is associated with similar stent patency rates and complications among patients with Budd-Chiari syndrome post-endovascular intervention.

Low Performance of a Clinical-Genetic Model in the Estimation of Time in Therapeutic Range in Acenocoumarol-Adherent Patients with Nonvalvular Atrial Fibrillation: The Quality of Anticoagulation Challenge

BACKGROUND

Anticoagulation with vitamin K antagonists continues to be a challenging task given the difficulty of achieving a correct time in therapeutic range (TTR). The SAMeTT2R2 score has been proposed to identify patients that will be good responders. In this study we aimed to analyse clinical and genetic factors involved in a correct level of anticoagulation in patients with atrial fibrillation and thereby potentially improve the diagnostic performance of SAMeTT2R2 score.

METHODS

We prospectively included 212 consecutive patients with nonvalvular atrial fibrillation under treatment with acenocoumarol for at least 6 months that were attended in a cardiology outpatient clinic and were categorized as adherent to medication. We carried out a multivariate regression analysis to detect the independent predictive factors of good control. In all patients VKORC1, CYP2C9⁎2, CYP2C9⁎3, and MIR133A2 genotyping was performed.

RESULTS

A total of 128 (60.4%) patients presented TTR <70% (average TTR = 63.2). We identified body mass index (OR 0.94, 95%CI 0.89-0.99, p=0.032) and regular vitamin K intake (OR 0.53, 95%CI 0.28-0.99, p= 0.046) as independent predictors of poor anticoagulation control. The discriminatory power of a clinical-genetic model derived from our cohort was significantly better compared to the SAMeTT2R2 score (C-statistic 0.658 versus 0.524, p<0.001).

CONCLUSIONS

In our study the SAMeTT2R2 score revealed a poor ability in the prediction of TTR. Besides SAMeTT2R2, body mass index and possibly vitamin K intake should be taken into account when deciding the optimal anticoagulation strategy. The information provided by the identified genotypes was marginal.

Associations between illness beliefs, medication beliefs, anticoagulation-related quality of life, and INR control: Insights from the Switching Study

BACKGROUND

Anticoagulation control with vitamin-K antagonists (VKAs) in patients with atrial fibrillation (AF) or venous thromboembolism (VTE) can be measured using time in therapeutic range (TTR), where TTR >65% is considered good and low TTR may be associated with low adherence.

METHODS

This cross-sectional observational study compared illness beliefs, treatment beliefs, and treatment satisfaction of patients with TTR >75% and TTR <50% using validated tools to determine their association with TTR. Adults requiring chronic VKA therapy were recruited from 2 hospital anticoagulation clinics in London, UK.

RESULTS

311 patients with TTR >75% and 214 with TTR <50% were recruited. TTR >75% patients had been taking warfarin on average over 2 years longer than TTR <50% patients (P < .001). Statistically significant differences in beliefs were found in all subscales other than in treatment control, general harm, and general overuse. Cluster analysis determined there were 4 distinct clusters of beliefs among patients. Multivariate binary logistic regression found VTE patients were least likely to have poor TTR (OR = 0.49; 95% CI 0.29, 0.77). Patients in the "cautious of therapy and fearful of illness" cluster were most likely to have low TTR (OR = 4.75; 95% CI 2.75, 8.77).

CONCLUSION

Illness perceptions, medication beliefs and treatment satisfaction were associated with INR control. VTE patients and those who were accepting of both illness and treatment were most likely to have optimal INR control.

Pharmacogenetics of vitamin K antagonists and bleeding risk prediction in atrial fibrillation

BACKGROUND

Polymorphisms in the vitamin K epoxide reductase complex 1 (VKORC1) and cytochrome P450 2C9 (CYP2C9) genes increase the bleeding risk in anticoagulated atrial fibrillation (AF) patients. Here, we aimed to investigate whether VKORC1 and CYP2C9 polymorphisms improved the predictive performance for major bleeding using the HAS-BLED score.

MATERIAL AND METHODS

We recruited 652 consecutive AF patients stable on vitamin K antagonist (INR 2.0-3.0) during at least the previous 6 months. A baseline venous blood sample was obtained for DNA extraction. We gave an extra point to the HAS-BLED score if the patient was a simultaneous carrier of the VKORC1 and CYP2C9 polymorphisms related to bleeding, and we called this modified score "GEN|HAS-BLED." During a median follow-up of 7.6 years (IQR 5.6-8.0), all major bleeding events were recorded.

RESULTS

During follow-up, 106 (16.2%) patients experienced a major bleeding (2.81%/y; 42 intracranial haemorrhages and 44 gastrointestinal bleeding) and 24 (3.7%) died from major bleeding (0.48%/y). Cox regression analyses demonstrated a significant association between HAS-BLED or GEN|HAS-BLED and major bleeds, both as continuous or categorical scores. Comparison of receiver operating characteristic (ROC) curves shows that original HAS-BLED clinical score had better predictive ability than GEN|HAS-BLED (0.660, 95% CI 0.622-0.696 vs 0.645, 95% CI 0.607-0.682; P = .030). Discrimination and reclassification analyses showed that GEN|HAS-BLED did not improve sensitivity compared with the original score and even showed significant negative reclassification.

CONCLUSION

Adding pharmacogenetic factors (ie polymorphisms of the VKORC1 and CYP2C9 genes) to the HAS-BLED score does not improve the prediction or discrimination performance for major bleeding.

Management of venous thromboembolism with non-vitamin K oral anticoagulants: A review for nurse practitioners and pharmacists

BACKGROUND AND PURPOSE

Venous thromboembolism (VTE), comprising deep-vein thrombosis and pulmonary embolism, is associated with significant morbidity and mortality. Non-vitamin K oral anticoagulants (NOACs), including apixaban, betrixaban, dabigatran, edoxaban, and rivaroxaban, are as effective and safe as vitamin K antagonists (VKAs) for primary prophylaxis, treatment, and/or secondary prevention of VTE and present significant advantages in convenience of use. This review provides guidance to nurse practitioners (NPs) and pharmacists on NOAC usage for the management of VTE and examines how traditional anticoagulation clinics can adapt to cater to patients on NOACs.

METHODS

A review of the scientific literature pertaining to treatment guideline recommendations, large randomized clinical trials, and real-world evidence studies related to VTE management was conducted.

CONCLUSIONS

With current data suggesting that NOACs may present as better alternatives over VKAs for the management of VTE, comprehensively educating NPs and pharmacists can help incorporate these agents in their clinical practice.

IMPLICATIONS FOR PRACTICE

Repurposing anticoagulation clinics, led by well-informed NPs and pharmacists, will allow effective integration and optimal management of patients with VTE taking NOACs as well as those taking VKAs.

The clinical course of symptomatic deep vein thrombosis after 3 months of anticoagulant therapy using fondaparinux/edoxaban or fondaparinux/vitamin K antagonist

Background

For the management of venous thromboembolism (VTE), providing anticoagulant therapy within the therapeutic range has been a major challenge, as conventional therapy with unfractionated heparin (UFH) and vitamin K antagonist (VKA) requires frequent laboratory monitoring and dose adjustment. Recently, fondaparinux and edoxaban are being used as beneficial alternatives to UFH and VKA.

Methods

We evaluated the clinical course of symptomatic deep vein thrombosis (DVT) in patients who received the 3-month anticoagulation therapy with fondaparinux/edoxaban (Group A; n=40) in comparison with the findings from our previous experience of patients who received the fondaparinux/VKA combination (Group B; n=33).

Results

In both Groups A and B, serum D-dimer was significantly improved after treatment (p<0.001). The thrombus volume assessed by quantitative ultrasound thrombosis (QUT) score was significantly reduced in both groups (p<0.001). There was no difference in the proportion of patients who were normalized (ie, disappearance of DVT) between the groups, although Group A had significantly more patients who were normalized or improved (ie, disappearance and reduction of DVT) (p<0.001). No bleeding event was observed in either group. However, in one patient in Group B, worsening of DVT and development of symptomatic PE were observed.

Conclusion

Fondaparinux/edoxaban therapy is as effective as fondaparinux/VKA. This treatment has the possible advantage in thrombus regression. This would be a beneficial therapeutic option for both patients and physicians.

Association between satisfaction with and adherence to warfarin therapy on the control of international normalized ratio: A hospital-based study in Saudi Arabia

BACKGROUND

High satisfaction with, and adherence to, warfarin therapy are linked to better international normalized ratio (INR) control and good therapeutic outcomes.

OBJECTIVE

This study was conducted to identify the association between satisfaction with, and adherence to, warfarin therapy and the control of the INR within the target therapeutic range.

METHODS

A cross-sectional study was conducted from June 1 to August 31, 2016, at the Anticoagulation Clinic in the Cardiology Center at King Fahad Hospital, Qassim, Saudi Arabia. All adult patients included in the study were 18-years-old or older and were on warfarin therapy for 6 months or more. The data were collected through face-to-face interviews using a structured questionnaire.

RESULTS

A total of 298 patients were included. Of them, 194 patients (65.1%) were males and 152 (51.0%) were classified as satisfied with their warfarin therapy. Secondary educational level and above (P = .001) and being non-Saudi (P = .026) were identified as determinants of a high level of satisfaction. Ninety-five (31.8%) participants were classified as adherent to the therapy, and satisfaction with treatment was the only predictor of adherence (P = .009). One hundred thirty-six patients (45.6%) achieved their target INR range. Satisfaction (P = .038) and adherence (P = .023) were significantly associated with better INR control.

CONCLUSION

Substantial efforts are needed to improve patient satisfaction and adherence to treatment through different strategies in order to achieve the target therapeutic goal for warfarin treatment.

Pharmacological and Non-pharmacological Treatments for Stroke Prevention in Patients with Atrial Fibrillation

Atrial fibrillation (AF) is associated with significant risk of stroke and other thromboembolic events, which can be effectively prevented using oral anticoagulation (OAC) with either vitamin K antagonists (VKAs) or non-VKA oral anticoagulants (NOACs) dabigatran, rivaroxaban, apixaban, or edoxaban. Until recently, VKAs were the only available means for OAC treatment. NOACs had similar efficacy and were safer than or as safe as warfarin with respect to reduced rates of hemorrhagic stroke or other intracranial bleeding in the respective pivotal randomized clinical trials (RCTs) of stroke prevention in non-valvular AF patients. Increasing “real-world” evidence on NOACs broadly confirms the results of the RCTs. However, individual patient characteristics including renal function, age, or prior bleeding should be taken into account when choosing the OAC with best risk–benefit profile. In patients ineligible for OACs, surgical or interventional stroke prevention strategies should be considered. In patients undergoing cardiac surgery for other reasons, the left atrial appendage excision, ligation, or amputation may be the best option. Importantly, residual stumps or insufficient ligation may result in even higher stroke risk than without intervention. Percutaneous left atrial appendage occlusion, although requiring minimally invasive access, failed to demonstrate reduced ischemic stroke events compared to warfarin. In this review article, we summarize current treatment options and discuss the strengths and major limitations of the therapies for stroke risk reduction in patients with AF.

In Potential Stroke Patients on Warfarin, the International Normalized Ratio Predicts Ischemia

BACKGROUND

Stroke can occur in patients on warfarin despite anticoagulation. Patients with a low international normalized ratio (INR) should theoretically be at greater risk for ischemia than those who are therapeutic. Therefore, INR may be able to indicate whether new neurological deficits are more likely strokes or stroke mimics in patients on warfarin. This study evaluates the association and predictive value of INR in determining the likelihood of ischemia.

METHODS

Patients were identified using the acute stroke registry at a Primary Stroke Center from January 2013 through December 2014. All adult patients undergoing evaluation for acute stroke with prior documented use of warfarin and an INR level at presentation were included. Data were collected regarding patient demographics, medical comorbidities, stroke severity, reason for anticoagulation, and laboratory studies including INR. Student t tests and χ2 analysis were used to evaluate factors associated with increased likelihood of ischemia (stroke or transient ischemic attack) versus mimic. Significant results were entered into a multivariable regression analysis. Sensitivity and specificity analyses were conducted to determine the predictive value of INR for ischemic risk.

RESULTS

116 patients were included; 46 were diagnosed with ischemia, 70 were diagnosed as mimics. 75% of patients were on warfarin for atrial fibrillation versus 25% for venous thrombosis. A statistically significant difference in mean INR for patients with ischemia (n = 46) versus mimics (n = 70) was observed (1.7 vs. 2.8; p < 0.001). In multivariable analysis, both sub-therapeutic INR (p < 0.001) and atrial fibrillation (p = 0.014) were predictors of ischemia. In patients with an INR ≥2, the predictive value of having a non-ischemic etiology was 79%. No patient with an INR of ≥3.6 was found to have ischemia.

CONCLUSIONS

Sub-therapeutic INR and atrial fibrillation are strongly associated with ischemia in patients on warfarin presenting with acute neurologic symptoms. Ischemia is far less likely in patients with an INR of ≥2 and rare in those with an INR ≥3.6. This study shows that the INR value of a patient on warfarin can help stratify patients' risk for acute ischemic stroke and guide further neurologic imaging and workup.

Use of direct oral anticoagulants in patients with atrial fibrillation in Scotland: Applying a coherent framework to drug utilisation studies

PURPOSE

To report the use of direct oral anticoagulants (DOACs) for stroke prevention in patients with atrial fibrillation in Scotland and advocate the standardisation of drug utilisation research methods.

METHODS

Retrospective cohort study using linked administrative data. Patients included those with a diagnosis of atrial fibrillation (confirmed in hospital) who received a first prescription for a DOAC (dabigatran, rivaroxaban, or apixaban) from September 2011 to June 2014. Drug utilisation measures included discontinuation, persistence, and adherence.

RESULTS

A total of 5398 patients (mean CHA₂ DS₂ -VASc score 2.98 [SD 1.71], 89.7% with ≥5 concomitant medicines) were treated with DOACs for a median of 228 days (interquartile range 105-425). Of 35.6% who discontinued DOAC treatment, 11.0% switched to warfarin, and 48.3% reinitiated DOACs. Persistence after 12 and 18 months was 75.9% and 69.8%, respectively. Differences between individual DOACs were observed: Discontinuation rates ranged from 20.4% (apixaban) to 60.6% (dabigatran) and 12 months persistence from 60.1% (dabigatran) to 85.5% (apixaban). Adherence to treatment with all DOACs was good: Overall DOAC median medication refill adherence was 102.9% (interquartile range 88.9%-115.5%), and 82.3% of patients had a medication refill adherence > 80%.

CONCLUSIONS

In Scotland, adherence to DOAC treatment was good, and switching from DOAC to warfarin was low. However, discontinuation and persistence rates were variable-although treatment interruptions were often temporary. To decrease the inconsistencies in drug utilisation methods and facilitate meaningful study comparison, the use of a coherent framework-using a combination of discontinuation, persistence, and adherence-and the standardisation of measurements is advocated.

Direct oral anticoagulants in patients with chronic kidney disease: patient selection and special considerations

Many patients with chronic kidney disease (CKD) receive anticoagulation or antiplatelet therapy due to atrial fibrillation, coronary artery disease, thromboembolic disease, or peripheral artery disease. The treatment usually includes vitamin K antagonists (VKAs) and/or platelet aggregation inhibitors. The direct oral anticoagulants (DOAC) inhibiting factor Xa or thrombin represent an alternative for VKAs. In patients with acute and chronic kidney disease, caution is warranted, as DOACs can accumulate as they are partly eliminated by the kidneys. Thus, they can potentially increase the bleeding risk in patients with CKD. In patients with an estimated glomerular filtration rate (eGFR) above 60 mL/min, DOACs can be used safely with greater efficacy and safety as compared to VKAs. In patients with CKD 3, DOACs are as effective as VKAs with a lower bleeding rate. The more the renal function declines, the lower is the advantage of DOACs over VKAs. Thus, use of DOACs should be avoided in patients with an eGFR below 30 mL/min, particularly, the compounds with a high renal elimination. Available data suggest that DOACs can also be used safely in older patients. In this review, use of DOACs in comparison with VKAs, heparins, and heparinoids, together with special considerations in patients with impaired renal function will be discussed.

The Future of Nanoparticle-Directed Venous Therapy

Nanoparticles, structures of less than 200 nm capable of delivering pharmacotherapeutics to sites of disease, have shown great promise for the treatment of many disease states. While no nanoparticle therapies for deep vein thrombosis are currently approved by the Food and Drug Administration, many of the unique features of these therapies have the potential to treat both deep vein thrombosis and its most significant sequela, postthrombotic syndrome, while limiting the hemorrhagic complications of current antithrombotic therapies. Nanoparticles are complex structures with several important variables that must be considered to engineer effective therapies. This article will review the structure and engineering of nanoparticles, as well as promising molecular targets for future investigation.

Anticoagulation Therapy and NOACs in Heart Failure

Current evidence indicates that heart failure (HF) confers a hyper-coagulable state that is associated with adverse events including stroke, systemic embolism, and mortality. This may be due to the elevated levels of pro-thrombotic and pro-inflammatory cytokines that are seen in patients with acute and chronic HF. Left ventricular wall motion abnormalities in patients with systolic dysfunction predispose to local thrombosis due to blood stasis as does atrial fibrillation (AF) which leads to blood stasis in regions of the atria. The high risk of thromboemboli in HF patients with AF has resulted in the use anticoagulation therapy to prevent the occurrence of catastrophic events. There is evidence, however, that the pro-inflammatory, pro-thrombotic state that exists in HF puts patients who are in sinus rhythm at risk. The novel oral anticoagulants (NOACs) have been shown in RCT to have at least equivalent efficacy in reducing stroke as warfarin while exposing patients to a lower risk of bleeding. The fact that the NOACs don't require routine monitoring to assure that patients remain within the therapeutic range and have relatively simple dosing requirements and a safer risk profile makes them attractive substitutes to warfarin in HF patients with atrial fibrillation and other conditions (e.g. deep venous thrombosis). Post hoc analyses from a subset of HF patients from the RCTs in AF patients have demonstrated similar findings as were reported in the entire populations that were included in the trials. As a result, NOACS are commonly used now in HF patients with AF. For HF patients with reduced ejection fraction in sinus rhythm, the use of warfarin in randomized clinical trials (RCT) to reduce stroke has been disappointing and associated with increase bleeding risk when compared to aspirin. The advantages of the NOACs over warfarin, however, raise the question of whether they might improve outcomes in HF patients who are in sinus rhythm. The currently ongoing COMMANDER-HF trial has been designed to address this issue. In this chapter we review evidence of existence of a prothombotic state in HF, the pharmacodynamics and clinical trials of the NOACs and the outcomes from NOAC substudies in the HF subgroup. We also discuss the rationale for using anticoagulation in HF independent of arrhythmia burden.