Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition)

High Soluble Thrombomodulin Is Associated with an Increased Risk of Major Bleeding during Treatment with Oral Anticoagulants: A Case-Cohort Study

BACKGROUND

 Major bleeding occurs in 1 to 3% of patients treated with oral anticoagulants per year. Biomarkers may help to identify high-risk patients. A proposed marker for major bleeding while using anticoagulants is soluble thrombomodulin (sTM).

METHODS

 Plasma was available from 16,570 patients of the BLEEDS cohort that consisted of patients who started treatment with vitamin K antagonists between 2012 and 2014. A case-cohort study was performed including all patients with a major bleed (n = 326) during follow-up and a random sample of individuals selected at baseline (n = 652). Plasma sTM levels were measured and stratified by percentiles. Patients were also categorized by international normalized ratio (INR). Adjusted hazard ratios (for age, sex, hypertension, and diabetes) with 95% confidence intervals (CIs) were estimated by means of Cox regression.

RESULTS

 Plasma sTM levels were available for 263 patients with a major bleed and 538 control subjects. sTM levels were dose-dependently associated with risk of major bleeding, with a 1.9-fold increased risk (95% CI: 1.1-3.1) for levels above the 85th percentile versus the <25th percentile. A high INR (≥4) in the presence of high (≥70th percentile) sTM levels was associated with a 7.1-fold (95% CI: 4.1-12.3) increased risk of major bleeding, corresponding with a bleeding rate of 14.1 per 100 patient-years.

CONCLUSION

 High sTM levels at the start of treatment are associated with major bleeding during vitamin K antagonist treatment, particularly in the presence of a high INR.

Evaluation of the Long-Term Impact on Quality After the End of Pharmacist-Driven Warfarin Therapy Management in Patients With Poor Quality of Anticoagulation Therapy

Background

Warfarin is the most common oral anticoagulant drug, especially in low-income and emerging countries, because of the high cost of direct oral anticoagulant (DOACs), or when warfarin is the only proven therapy (mechanical prosthetic valve and kidney dysfunction). The quality of warfarin therapy is directly associated with dose management. Evidence shows that pharmaceutical care achieves a better quality of therapy with warfarin. However, there are no studies showing this intervention in a specific patient group with poor quality of anticoagulation in a long period after the end of the follow-up by a pharmacist. Thus, the aim of this study was to evaluate whether the quality of warfarin therapy driven by a pharmacist remains stable in the long term after the end of follow up with a pharmacist, in AF patients with poor quality of anticoagulation.

Methods

This is a prospective study, which evaluated about 2,620 patients and selected 262 patients with AF and poor quality of anticoagulation therapy with warfarin (TTR<50% - based on the last three values of international normalized ratio). Pharmacist-driven therapy management was performed up to 12 weeks. Data from patients were evaluated 1 year after the end of the follow-up with pharmacist.

Results

Comparison between mean TTR after 12 weeks of pharmaceutical care (54.1%) and mean TTR one year after the end of the pharmaceutical care (56.5%; p=0.081) did not achieve statistical difference, demonstrating that the increment of quality due to intervention of 12 weeks was maintained for 1 year after intervention.

Conclusion

The long-term impact of pharmaceutical care was beneficial for patients with AF and poor quality of warfarin anticoagulation. This design might be an important strategy to treat a subgroup of patients without proven effectiveness of warfarin.

Management of Outpatient Warfarin Therapy amid COVID-19 Pandemic: A Practical Guide

Many healthcare resources have been and continue to be allocated to the management of patients with COVID-19. Therefore, the ongoing care of patients receiving oral anticoagulation with warfarin is likely to be compromised amid this unprecedented crisis. This article discusses a stepwise algorithm for the management of outpatient warfarin therapy. Alternative management strategies are presented and discussed, including alternative pharmacological therapy options and self-monitoring. Our algorithm aims to help clinicians safely optimize the treatment of patients requiring anticoagulation therapy in the context of the global response to the current pandemic.

New oral anticoagulants for nonvalvular atrial fibrillation with peripheral artery disease: a meta-analysis

BACKGROUND

New oral anticoagulants (NOACs) are as effective and safe as warfarin for patients with non-valvular atrial fibrillation (NVAF). Limited evidence is available regarding outcomes for NVAF patients with peripheral artery disease (PAD).

METHODS

A systematic search of Medline, Embase, and the Cochrane Library was performed. Two reviewers independently performed data extraction and quality assessment using the Cochrane Collaboration tool for assessing risk of bias. All primary publications and secondary analyses comparing NOACs with other oral anticoagulation regimens for the prevention of stroke in patients with both NVAF and PAD from phase III clinical trials were evaluated. The primary outcomes were stroke, systemic embolism (SE), major bleeding, and intracranial hemorrhage (ICH), and the secondary outcomes were cardiovascular (CV) mortality, all-cause mortality, and myocardial infarction (MI).

RESULTS

Three articles were included in this study. The pooled results showed a relative risk for stroke/SE with NOACs of 0.86 (95% confidence interval [CI]: 0.53-1.39), for major bleeding, 1.12 (95% CI: 0.70-1.81), for ICH, 0.47 (95% CI: 0.16-1.36), for CV mortality, 0.77 (95% CI: 0.57-1.04), for all-cause mortality, 0.91 (95% CI: 0.70-1.19), and for MI, 1.10 (95% CI: 0.64-1.90).

CONCLUSION

The findings show that NOACs are effective and safe for preventing stroke/SE in patients with both NVAF and PAD.

Primary prophylaxis for venous thromboembolism in people undergoing major amputation of the lower extremity

BACKGROUND

People undergoing major amputation of the lower limb are at increased risk of venous thromboembolism (VTE). Risk factors for VTE in amputees include advanced age, sedentary lifestyle, longstanding arterial disease and an identifiable hypercoagulable condition. Evidence suggests that pharmacological prophylaxis (e.g. heparin, factor Xa inhibitors, vitamin K antagonists, direct thrombin inhibitors, antiplatelets) is effective in preventing deep vein thrombosis (DVT), but is associated with an increased risk of bleeding. Mechanical prophylaxis (e.g. antiembolism stockings, intermittent pneumatic compression and foot impulse devices), on the other hand, is non-invasive and has minimal side effects. However, mechanical prophylaxis is not always appropriate for people with contraindications such as peripheral arterial disease (PAD), arteriosclerosis or bilateral lower limb amputations. It is important to determine the most effective thromboprophylaxis for people undergoing major amputation and whether this is one treatment alone or in combination with another. This is an update of the review first published in 2013.

OBJECTIVES

To determine the effectiveness of thromboprophylaxis in preventing VTE in people undergoing major amputation of the lower extremity.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase and Cumulative Index to Nursing and Allied Health Literature databases, the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 5 November 2019. We planned to undertake reference checking of identified trials to identify additional studies. We did not apply any language restrictions.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised controlled trials which allocated people undergoing a major unilateral or bilateral amputation (e.g. hip disarticulation, transfemoral, knee disarticulation and transtibial) of the lower extremity to different types or regimens of thromboprophylaxis (including pharmacological or mechanical prophylaxis) or placebo.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data and assessed risk of bias. We resolved any disagreements by discussion. Outcomes of interest were VTE (DVT and pulmonary embolism (PE)), mortality, adverse events and bleeding. We used GRADE criteria to assess the certainty of the evidence. The two included studies compared different treatments, so we could not pool the data in a meta-analysis.

MAIN RESULTS

We did not identify any eligible new studies for this update. Two studies with a combined total of 288 participants met the inclusion criteria for this review. Unfractionated heparin compared to low molecular weight heparin One study compared unfractionated heparin with low molecular weight heparin and found no evidence of a difference between the treatments in the prevention of DVT (odds ratio (OR) 1.23, 95% confidence interval (CI) 0.28 to 5.35; 75 participants; very low-certainty evidence). No bleeding events occurred in either group. Deaths and adverse events were not reported. This study was open-label and therefore at a high risk of performance bias. Additionally, the study did not report the method of randomisation, so the risk of selection bias was unclear. Heparin compared to placebo In the second study, there was no evidence of a benefit from heparin use in preventing PE when compared to placebo (OR 0.84, 95% CI 0.35 to 2.01; 134 participants; low-certainty evidence). Similarly, no evidence of improvement was detected when the level of amputation was considered, with a similar incidence of PE between the two treatment groups: above knee amputation (OR 0.79, 95% CI 0.31 to 1.97; 94 participants; low-certainty evidence); and below knee amputation (OR 1.53, 95% CI 0.09 to 26.43; 40 participants; low-certainty evidence). Ten participants died during the study; five underwent a post-mortem and three were found to have had a recent PE, all of whom had been on placebo (low-certainty evidence). Bleeding events were reported in less than 10% of participants in both treatment groups, but the study did not present specific data (low-certainty evidence). There were no reports of other adverse events. This study did not report the methods used to conceal allocation of treatment, so it was unclear whether selection bias occurred. However, this study appeared to be free from all other sources of bias. No study looked at mechanical prophylaxis.

AUTHORS' CONCLUSIONS

We did not identify any eligible new studies for this update. As we only included two studies in this review, each comparing different interventions, there is insufficient evidence to make any conclusions regarding the most effective thromboprophylaxis regimen in people undergoing lower limb amputation. Further large-scale studies of good quality are required.

Anticoagulation Therapy for Non-valvular Atrial Fibrillation: A Mini-Review

Anticoagulation therapy is an important method of preventing stroke in individuals with atrial fibrillation (AF). Atrial fibrillation is a quivering or irregular heartbeat that can lead to blood clots, stroke, heart failure, and other heart-related complications. Clinical guidelines on AF consistently recommend long-term oral warfarin to treat valvular atrial fibrillation (VAF). However, due to varying risks of blood clots and stroke associated with different types of non-valvular atrial fibrillation NVAF, it is unclear whether direct oral anticoagulant (DOAC) can replace warfarin. Despite a recent increase in evidence on the effectiveness and the importance of anticoagulant therapy in preventing thromboembolic events associated with NVAF, clinical prevention strategies remain complex. Given the complexities associated with clinical use of anticoagulants for patients with NVAF, this review aims to offer guidance on patient anticoagulant use based on current available evidence.

A European consensus statement on the use of four-factor prothrombin complex concentrate for cardiac and non-cardiac surgical patients

Modern four-factor prothrombin complex concentrate was designed originally for rapid targeted replacement of the coagulation factors II, VII, IX and X. Dosing strategies for the approved indication of vitamin K antagonist-related bleeding vary greatly. They include INR and bodyweight-related protocols as well as fixed dose regimens. Particularly in the massively bleeding trauma and cardiac surgery patient, four-factor prothrombin complex concentrate is used increasingly for haemostatic resuscitation. Members of the Transfusion and Haemostasis Subcommittee of the European Association of Cardiothoracic Anaesthesiology performed a systematic literature review on four-factor prothrombin complex concentrate. The available evidence has been summarised for dosing, efficacy, drug safety and monitoring strategies in different scenarios. Whereas there is evidence for the efficacy of four-factor prothrombin concentrate for a variety of bleeding scenarios, convincing safety data are clearly missing. In the massively bleeding patient with coagulopathy, our group recommends the administration of an initial bolus of 25 IU.kg^-1 . This applies for: the acute reversal of vitamin K antagonist therapy; haemostatic resuscitation, particularly in trauma; and the reversal of direct oral anticoagulants when no specific antidote is available. In patients with a high risk for thromboembolic complications, e.g. cardiac surgery, the administration of an initial half-dose bolus (12.5 IU.kg^-1 ) should be considered. A second bolus may be indicated if coagulopathy and microvascular bleeding persists and other reasons for bleeding are largely ruled out. Tissue-factor-activated, factor VII-dependent and heparin insensitive point-of-care tests may be used for peri-operative monitoring and guiding of prothrombin complex concentrate therapy.

Warfarin and food, herbal or dietary supplement interactions: A systematic review

AIMS

To present an updated overview on the safety of concurrent use of food, herbal or dietary supplement and warfarin.

METHODS

A systematic literature review was performed on 5 databases from inception up to 31 December 2019. These interactions were classified depending on the likelihood of interaction and supporting evidences.

RESULTS

A total of 149 articles describing 78 herbs, food or dietary supplements were reported to interact with warfarin. These reports described potentiation with 45 (57.7%) herbs, food or dietary supplements while 23 (29.5%) reported inhibition and 10 (12.8%) reported limited impact on warfarin pharmacokinetics and pharmacodynamics. Twenty unique herb and dietary supplements also reported to result in minor bleeding events, such as purpura and gum bleeding as well as major events such as intracranial bleeding that led to death.

CONCLUSION

While most food, herbs and supplements can be safely taken in moderation, healthcare professionals should be aware of the increased risk of bleeding when taking several food and herbs. These include Chinese wolfberry, chamomile tea, cannabis, cranberry, chitosan, green tea, Ginkgo biloba, ginger, spinach, St. John's Wort, sushi and smoking tobacco. Patients should be counselled to continue to seek advice from their healthcare professionals when starting any new herbs, food or supplement.

[Results of treatment with oral anticoagulants in patients with lower limb deep vein thrombosis]

Analysed herein is the incidence rate of decompensated forms of venous insufficiency in patients who endured lower limb deep vein thrombosis and were prescribed either warfarin, rivaroxaban in therapeutic doses or rivaroxaban in a preventive dose. The study enrolled a total of 129 patients presenting with thrombotic lesions of deep veins of the lower limbs. The patients were divided into three groups depending on the anticoagulant therapy prescribed. Patients of the first and second groups for 6 months received warfarin and rivaroxaban, respectively, in therapeutic doses, and group three patients continued taking rivaroxaban in a therapeutic dose for a long time. RESULTS: Eighteen (36%) patients from the first group and two (4.5%) patients from the second group discontinued taking the anticoagulant before the scheduled date. Relapses of venous thromboembolic complications were observed in 11 (22%) group one patients and in 7 (15.9%) group two patients, with no relapses observed in the third group. Negative dynamics of the ultrasonographic picture was observed in two groups: 16% of group one patients and 9.1% of group two patients were found to develop signs of damage of previously unaltered veins or occlusion of a previously patent vein after endured thrombosis without clinical manifestation. Trophic disorders were observed in a third of patients of the first group and in one patient of the second group by the fourth year of follow up. None of the third group patients developed trophic ulcers. Statistically significant differences in the examined groups were obtained for such parameters as adherence to treatment and the degree of severity of venous insufficiency, in favour of rivaroxaban, with quality of recanalization being significantly better in the third group. A conclusion was drawn that prolonged preventive administration of new oral anticoagulants did not lead to the development of decompensated forms of venous insufficiency.

Periprocedural Management of Oral Anticoagulation

Decisions surrounding periprocedural anticoagulation management must balance thromboembolic and procedural bleed risk. The interruption of both warfarin and DOACs requires consideration of anticoagulant pharmacokinetics, procedural bleed risk and patient characteristics. There is a diminishing role for periprocedural bridging LMWH overall and no role for bridging LMWH for the procedural interruption of DOACs. A clinical approach to perioperative DOAC management based on operative bleeding risk and renal function is safe and effective, and at present, is preferred over preprocedural DOAC levels testing. Clear communication of the anticoagulation interruption plan to both the patient and the patient's care team is essential.

The effects of CYP2C9 and VKORC1 gene polymorphisms on warfarin maintenance dose in Turkish cardiac patients

Aim: Our aim was to examine the effect of CYP2C9 and VKORC1 polymorphisms on warfarin dose requirements in Turkish patients. Materials & methods: 24 warfarin prescribed patients were included and analyzed for eight VKORC1 and 6 CYP2C9 polymorphisms in the study. Results: Patients with CYP2C9 *1/*1 and VKORC1 -1639 GG and GA genotypes required higher warfarin doses in comparison to wild type VKORC1 genotype. Patients with CYP2C9 *1/*3 and VKORC1 -1639 GG genotypes simultaneously, required the lowest dose of warfarin (4.64 mg/day). Patients with CYP2C9 *1/*1 and VKORC1 9041 AA genotype were found to require higher warfarin doses. Conclusion: Our results provide additional evidence to support the hypothesis that CYP2C9 *2, *3, VKORC1 9041 G > A polymorphisms explain considerable proportion of inter-individual variability in warfarin dose requirement.

Implant Placement in Patients under Treatment with Rivaroxaban: A Retrospective Clinical Study

The management of patients under treatment with Direct Oral Anticoagulants (DOACs) has led clinicians to deal with two clinical issues, such as the hemorrhagic risk in case of non-interruption or the risk of thromboembolism in case of suspension of the treatment. The primary aim of this retrospective study was to evaluate the incidence of perioperative bleeding events and healing complications in patients who were under treatment with Rivaroxaban and who received dental implants and immediate prosthetic restoration. Patients treated with Rivaroxaban (Xarelto 20 mg daily) and who needed implant rehabilitation were selected. Four to six implants were placed in mandibular healed sites or fresh extraction sockets. All patients, in agreement with their physicians, interrupted the medication for 24 h and received implants and immediate restorations. Twelve patients and 57 implants were analyzed in the study. No major postoperative bleeding events were reported. Three patients (25%) presented slight immediate postoperative bleeding controlled with compression only. The implant and prosthetic survival rate were both 100% after 1 year. Within the limitations of this study, multiple implant placement with an immediate loading can be performed without any significant complication with a 24 h discontinuation of Rivaroxaban, in conjunction with the patient’s physician.

Comparative effectiveness and safety of direct oral anticoagulants compared to warfarin in morbidly obese patients with acute venous thromboembolism: systematic review and a meta-analysis

Direct oral anticoagulant (DOAC) agents are becoming the anticoagulation strategy of choice. However, their use in the treatment of acute venous thromboembolism (VTE) in morbidly obese patients (bodyweight of > 120 kg or BMI > 40 kg/m²) guarded. This is due to the scarce data supporting their use in this population. As a result, the International Society on Thrombosis and Haemostasis recommended against their use in this cohort of patients. New data emerged supporting the use of DOACs in these patients. Hence, we aimed to systematically review the literature exploring the efficacy and safety of these agents compared to warfarin in VTE treatment in morbidly obese patients. A systematic review of PubMed and EMBASE since inception until 01/04/2020. Subsequently, a non-inferiority (NI of 1.75) meta-analysis utilizing the random-effects model. Five observational studies (6585 patients) were included in our meta-analysis. DOAC analogs were non-inferior compared to warfarin in reducing the primary efficacy outcome of VTE recurrence (OR 1.07, 95% CI 0.93-1.23) and the primary safety outcome (major bleeding events) (OR 0.80, 95% CI 0.54-1.17). Our meta-analysis comprising real-world observational data concludes that the use of DOAC analogs in morbidly obese patients (bodyweight of > 120 kg or BMI > 40 kg/m²) is non-inferior with regards to efficacy and safety compared to warfarin. This finding helps to resolve the uncertainty associated with the use of DOACs in this cohort. Additionally, it invites for a confirmatory non-inferiority randomized controlled trial testing DOAC vs. Warfarin in this group of patients.

Periprocedural Outcomes in Patients on Chronic Anticoagulation Undergoing Fistulograms

BACKGROUND

Management of antithrombotic therapy with warfarin in patients undergoing fistulograms and possible interventions is controversial and difficult because of lack of adequate outpatient bridging options. Our goal was to assess periprocedural outcomes in patients managed using different anticoagulation strategies.

METHODS

A retrospective, single-institution analysis of all patients on chronic anticoagulation with warfarin undergoing fistulograms from 2011 to 2017 was performed. Anticoagulation management strategies were classified as suspended warfarin (SW), continued warfarin (CW), and a heparin bridge with suspended warfarin (HB). Periprocedural outcomes were analyzed.

RESULTS

There were 87 patients on chronic anticoagulation with warfarin who underwent 175 fistulograms. Median age was 63 years, and 43.4% were women. Indications for warfarin included atrial fibrillation (53%), prior pulmonary embolism/deep vein thrombosis (29%), and hypercoagulable state (14%). Distribution was SW (60%), CW (26%), and HB (14%). Approximately half (53%) were same-day procedures, 30% occurred during access-related admissions, and 14% were performed during nonaccess-related admissions. Common indications for a fistulogram included difficulty with dialysis (63.4%), access thrombosis (20.6%), and poor maturation (10.3%). Interventions included angioplasty (82.9%), thrombectomy/embolectomy (20.6%), and stenting (8.6%). Thirty-day outcomes for SW versus CW versus HB were similar for bleeding complications (5.7%, 6.5%, 8.3%; P = 0.89), systemic thrombotic complications (3.8%, 2.2%, 0%; P = 0.569), access rethrombosis (7.6%, 13%, 12.5%; P = 0.517), and tunneled dialysis catheter placement (11.4%, 13%, 12.5%; P = 0.958). After excluding procedures performed during a nonaccess-related admission, length of stay (LOS) was highest among HB (9.6 ± 7.8 days) compared with SW (2.6 ± 5.9 days) and CW (1 ± 2.8 days), (P < 0.0001).

CONCLUSIONS

CW therapy in patients undergoing fistulograms was not associated with increased morbidity and was associated with shorter LOS. Bridging with heparin is not associated with improved outcomes, warranting a thorough consideration of continuing warfarin is safe and may streamline preservation of dialysis accesses without significantly increasing resource utilization.

Management of oral anticoagulants prior to emergency surgery or with major bleeding: A survey of perioperative practices in North America: Communication from the Scientific and Standardization Committees on Perioperative and Critical Care Haemostasis and Thrombosis of the International Society on Thrombosis and Haemostasis

BACKGROUND

There is limited information on real-world practice versus current clinical practice guidelines for oral anticoagulant reversal before emergency surgery.

OBJECTIVE

To identify current practice/knowledge gaps for oral anticoagulant reversal emergency surgery among anesthesiologists.

METHODS

A 22-question survey covering aspects of clinical practice relating to oral anticoagulant reversal was sent to American Society of Anesthesiology members with weekly reminders during data collection from October to December 2018.

RESULTS

Responses were received from 2315 anesthesiologists of which 86% of respondents were United States based. Emergency surgery was defined as occurring within 4 hours of the decision to operate by 60% of respondents. Fresh frozen plasma (FFP) was used by 75% of respondents for vitamin K antagonist (VKA) reversal and by 54% for direct oral anticoagulant (DOAC) reversal in emergency surgery and 67% in major operative bleeding. Only 32% of institutions had emergency anticoagulant reversal protocols, and 54% of respondents selected an international normalized ration (INR) ratio goal for VKA reversal of ≤1.5. Only 13% initially consulted or coordinated management with hematologists, and the final decision regarding coagulation management was made by the respondent in 26% of cases. A coordinated approach with hematologists and cardiologists was reported by 64%, and over half (51%) required approval for prothrombin complex concentrate administration for emergency procedures.

CONCLUSIONS

Despite recommendations to the contrary, FFP is extensively used for emergency VKA and DOAC reversal. There is a clear need for institutions to develop guideline-informed recommendations/management algorithms based on input from medical professionals routinely involved in management of these patients.

Perioperative management of patients receiving non-vitamin K antagonist oral anticoagulants: up-to-date recommendations

Indications of non-vitamin K antagonist oral anticoagulants (NOACs), consisting of two types: direct thrombin inhibitor (dabigatran) and direct factor Xa inhibitor (rivaroxaban, apixaban, and edoxaban), have expanded over the last few years. Accordingly, increasing number of patients presenting for surgery are being exposed to NOACs, despite the fact that NOACs are inevitably related to increased perioperative bleeding risk. This review article contains recent clinical evidence-based up-to-date recommendations to help set up a multidisciplinary management strategy to provide a safe perioperative milieu for patients receiving NOACs. In brief, despite the paucity of related clinical evidence, several key recommendations can be drawn based on the emerging clinical evidence, expert consensus, and predictable pharmacological properties of NOACs. In elective surgeries, it seems safe to perform high-bleeding risk surgeries 2 days after cessation of NOAC, regardless of the type of NOAC. Neuraxial anesthesia should be performed 3 days after cessation of NOACs. In both instances, dabigatran needs to be discontinued for an additional 1 or 2 days, depending on the decrease in renal function. NOACs do not require a preoperative heparin bridge therapy. Emergent or urgent surgeries should preferably be delayed for at least 12 h from the last NOAC intake (better if > 24 h). If surgery cannot be delayed, consider using specific reversal agents, which are idarucizumab for dabigatran and andexanet alfa for rivaroxaban, apixaban, and edoxaban. If these specific reversal agents are not available, consider using prothrombin complex concentrates.

Patient self-management of oral anticoagulation with vitamin K antagonists in everyday practice: clinical outcomes in a single centre cohort after long-term follow-up

Background

Patient self-management (PSM) of vitamin K antagonists (VKA) seems a very promising model of care for oral anticoagulation in terms of efficacy and safety. In comparison with other management models of VKA therapy, the number of scientific publications supporting the advantages of PSM is more limited. Currently, most of the scarce information comes from randomized clinical trials. Moreover, a small number of studies have assessed PSM of VKA therapy in real life conditions.

Methods

We analyzed clinical outcomes of 927 patients in a single center (6018.6 patient-years of follow-up). Recruitment took place between 2002 and 2017. All patients followed a structured training program, conducted by specialized nurses.

Results

Fifty percent of individuals had a mechanical heart valve (MHV), 23% suffered from recurrent venous thromboembolism (VTE) or high-risk thrombophilia, and 13% received VKA therapy because of atrial fibrillation (AF). Median follow-up was 6.5 years (range 0.1–15.97 years), median age was 58.1 years (IQR 48–65.9) and 46.5% were women. The incidence of major complications (either hemorrhagic or thromboembolic) was 1.87% patient-years (pt-ys) with a 95% CI of 1.54–2.27. The incidence of major thromboembolic events was 0.86% pt-ys (95% CI 0.64–1.13) and that of major hemorrhagic events was 1.01% pt-ys (95% CI 0.77–1.31). The incidence of intracranial bleeding was 0.22% pt-ys (95% CI 0.12–0.38). In terms of clinical indication for VKA therapy, the incidence of total major complications was 2.4% pt-ys, 2.0% pt-ys, 0.9% pt-ys and 1.34% pt-ys for MHV, AF, VTE and other (including valvulopathies and myocardiopathies), respectively. Clinical outcomes were worse in patients with multiple comorbidities, previous major complications during conventional VKA therapy, and in older individuals. The percentage of time in therapeutic range (TTR) was available in 861 (93%) patients. Overall, the mean (SD) of TTR was 63.6 ± 13.4%, being higher in men (66.2 ± 13.1%) than women (60.6 ± 13.2%), p < 0.05.

Conclusions

In terms of clinically relevant outcomes (incidence of major complications and mortality), PSM in real life setting seems to be a very good alternative in properly trained patients.

A Pharmacogenetically Guided Acenocoumarol Dosing Algorithm for Chilean Patients: A Discovery Cohort Study

Background

Vitamin K antagonists (VKA) are used as prophylaxis for thromboembolic events in patients with cardiovascular diseases. The most common VKA are warfarin and acenocoumarol. These drugs have a narrow therapeutic margin and high inter-individual response variability due to clinical and pharmacogenetic variables.

Objective

The authors aim to develop an algorithm comprised of clinical and genetic factors to explain the variability in the therapeutic dose of acenocoumarol among Chilean patients

Methodology

DNA was obtained from 304 patients as a discovery cohort with an international normalized ratio (INR) range of 2.0–3.0. The non-genetic (demographic and clinical) variables were also recorded. Genotype analyses were performed using real-time PCR for VKORC1 (rs9923231), VKORC1 (rs7294), GGCx (rs11676382), CYP4F2 (rs2108622), ABCB1 (rs1045642), CYP2C9*2 (rs1799853), ApoE (rs429358), and CYP2C9*3 (rs1057910).

Results

The clinical variables that significantly influenced the weekly therapeutic dose of VKA were age, sex, body mass index (BMI), and initial INR, collectively accounting for 19% of the variability, and the genetic variables with a significant impact were VKORC1 (rs9923231), CYP2C9*2 (rs1799853), and CYP2C9*3 (rs1057910), explaining for another 37% of the variability.

Conclusion

We developed an algorithm that explains 49.99% of the variability in therapeutic VKA dosage in the Chilean population studied. Factors that significantly affected the dosage included VKORC1, CYP2C9*2, and CYP2C9*3 polymorphisms, as well as age, sex, BMI, and initial INR.

Plasma Metabolites as Predictors of Warfarin Outcome in Atrial Fibrillation

BACKGROUND

Warfarin is prescribed as an oral anticoagulant to treat/prevent thromboembolism in conditions such as atrial fibrillation. As there is a narrow therapeutic window, treatment with warfarin is challenging. Pharmacometabonomics using nuclear magnetic resonance (NMR) spectroscopy may provide novel techniques for the identification of novel biomarkers of warfarin.

PURPOSE

The aim was to determine the metabolic fingerprint that predicts warfarin response based on the international normalized ratio (INR) in patients who are already receiving warfarin (phase I: identification) and to ascertain the metabolic fingerprint that discriminates stable from unstable INR in patients starting treatment with warfarin (phase II: validation).

EXPERIMENTAL APPROACH

A total of 94 blood samples were collected for phase I: 44 patients with stable INR and 50 with unstable INR. Meanwhile, 23 samples were collected for phase II: nine patients with stable INR and 14 with unstable INR. Data analysis was performed using multivariate analysis including principal component analysis and partial least square-discriminate analysis (PLS-DA), followed by univariate and multivariate logistic regression (MVLR) to develop a model to identify unstable INR biomarkers.

KEY RESULTS

For phase I, the PLS-DA model showed the following results: sensitivity 93.18%, specificity 91.49% and accuracy 92.31%. In the MVLR analysis of phase I, ten regions were associated with unstable INR. For phase II, the PLS-DA model showed the following results: sensitivity 66.67%, specificity 61.54% and accuracy 63.64%.

CONCLUSIONS AND IMPLICATIONS

We have shown that the pharmacometabonomics technique was able to differentiate between unstable and stable INR with good accuracy. NMR-based pharmacometabonomics has the potential to identify novel biomarkers in plasma, which can be useful in individualizing treatment and controlling warfarin side effects, thus, minimizing undesirable effects in the future.

Clinical Outcomes of Telephone Service for Patients on Warfarin: A Systematic Review and Meta-Analysis

Objective: To evaluate clinical outcomes of telephone-based service for patients on warfarin. Methods: Five bibliographic databases and gray literature were searched for articles that reported the effects of telephone interventions provided to patients using warfarin compared with those receiving usual clinic-based care. Mean difference (MD) and relative risk (RR) were used to calculate the effects of telephone intervention on time in therapeutic range (TTR) and visit in range (VIR), respectively. Adverse events (AEs) were pooled and reported as incidence rate ratios. Results: A total of 1,840 articles were examined. Eight articles involving 8,087 subjects were included in the quantitative synthesis. The pooled estimates from seven studies showed no difference on TTR between the telephone service group and the usual care group (MD 2.30; 95% confidence interval [CI] -3.56 to 8.16). In addition, VIR in the telephone service group was not different from the usual care group (RR 1.22, 95% CI 0.87-1.71). Moreover, patients in telephone service groups appeared to have a lower incidence of AEs compared with usual care groups. Discussion: Telephone-based service could be considered as an alternative anticoagulant management. However, owing to a lack of evidence from well-designed studies, further high-quality randomized control trials are warranted.

Review of Therapeutic Options for the Prevention of VTE in Total Joint Arthroplasty

Hip and knee arthroplasty patients are at high risk of perioperative venous thromboembolic events (VTE). VTE has been well studied in this population and it is recommended that total joint arthroplasty recipients receive chemoprophylactic anticoagulation due to risk factors inherent to the surgical intervention. There are few concise resources for the orthopedic surgeon that summarize data regarding post-operative anticoagulation in the context of currently available therapeutic options and perioperative standards of practice. The periodic reexamination of literature is essential as conclusions drawn from studies predating perioperative protocols that include early mobilization and sequential compression devices as standards of practice in total joint arthroplasty are no longer generalizable to modern-day practice. We reviewed a large number of recently published research studies related to post-operative anticoagulation in total joint arthroplasty populations that received a high Level of Evidence grade. Current literature supports the use of oral aspirin regimens in place of more aggressive anticoagulants, particularly among low risk patients. Oral aspirin regimens appear to have the additional benefit of lower rates of bleeding and wound complications. Less consensus exists among high risk patients and more potent anticoagulants may be indicated. However, available evidence does not demonstrate clear superiority among current options, all of which may place patients at a higher risk of bleeding and wound complications. In this situation, chemoprophylactic selection should reflect specific patient needs and characteristics.

Representation of patients with a migration background in studies on antithrombotic treatment. An analysis of recruitment data from a cluster randomized controlled trial

Background

The health status, health awareness and health behavior of persons with a migration background often differ from the autochthonous population. Little is known about the proportion of patients with a migration background (PMB) that participate in primary care studies on oral antithrombotic treatment (OAT) in Germany, and whether the quality of their antithrombotic care differs from patients without a migration background. The aim of this paper was to use the results of a cluster-randomized controlled trial (PICANT) to determine the proportion of PMB at different stages of recruitment, and to compare the results in terms of sociodemographic characteristics and antithrombotic treatment.

Methods

This study used screening and baseline data from the PICANT trial on oral anticoagulation management in GP practices. For this analysis, we determined the proportion of PMB during the recruitment period at stage 1 (screening of potentially eligible patients), stage 2 (eligible patients invited to participate in the trial), and stage 3 (assessment of baseline characteristics of patients participating in the PICANT trial). In addition, we compared patients in terms of sociodemographic characteristics and quality of anticoagulant treatment. Statistical analysis comprised descriptive and bivariate analyses.

Results

The proportion of PMB at each recruitment stage declined from 9.1% at stage 1 to 7.9% at stage 2 and 7.3% at stage 3). A lack of German language skills led to the exclusion of half the otherwise eligible PMB. At stages 1 and 3, PMB were younger (stage 1: 70.7 vs. 75.0 years, p<0.001; stage 3: 70.2 vs. 73.5 years, p = 0.013), but did not differ in terms of gender. The quality of their anticoagulant care was comparable (100.0% vs. 99.1% were receiving appropriate OAT, 94.4% vs. 95.7% took phenprocoumon, or warfarin, and the most recent INR measurement of 60.8% vs. 69.3% was within their individual INR range).

Conclusions

In the potentially eligible population and among participants at baseline, the quality of anticoagulant care was high in all groups of patients, which is reassuring. To enable the inclusion of more PMB, future primary care research on OAT in Germany should address how best to overcome language barriers. This will be challenging, particularly because the heterogeneity of PMB means the resulting sample sizes for each specific language group are small.

Trial registration

Current Controlled Trials ISRCTN41847489.

Acute thrombocytopenia after anticoagulation with rivaroxaban: A case report

BACKGROUND

Novel oral anticoagulants (NOACs) are commonly used for the anticoagulation of patients with atrial fibrillation. Reports of thrombocytopenic toxicity of NOACs are limited. In this report, we present a case of thrombocytopenia likely induced by rivaroxaban, which is an extremely rare adverse drug reaction.

CASE SUMMARY

A 70-year-old man presented to the cardiovascular department with a chief complaint of intermittent chest tightness and dyspnea over the last five years. Vital signs were within normal limits at presentation, with a heart rate of 65 beats/min, blood pressure of 138/78 mmHg, respiratory rate of 19 breaths/min, and temperature of 36.1°C. Laboratory tests indicated a platelet count of 163 × 10⁹/L on admission. Anticoagulant therapy with rivaroxaban, a NOAC, was started on the second day of hospitalization. The platelet count decreased to 30 × 10⁹/L on hospital day 11 and then 10 × 10⁹/L on day 12. Rivaroxaban was stopped on day 13 when the platelet count decreased to 5 × 10⁹/L. After the cessation of rivaroxaban, the platelet count returned to normal. The patient was diagnosed with thrombocytopenia, which was likely induced by rivaroxaban. The incidence of thrombocytopenic toxicity of NOACs is extremely low.

CONCLUSION

Thrombocytopenia during anticoagulation therapy may be associated with a high risk of life-threatening bleeding. For elderly patients, changes in platelet count should be carefully monitored at the beginning of NOAC treatment, and we should be on the alert for bleeding events as well.

Quantification of apixaban in human plasma using ultra performance liquid chromatography coupled with tandem mass spectrometry

Apixaban, an inhibitor of direct factor Xa, is used for the treatment of venous thromboembolic events or prevention of stroke. Unlike many other anticoagulant agents, it does not need periodic monitoring. However, monitoring is still required to determine the risk of bleeding due to overdose or surgery. Usually, apixaban concentrations are indirectly quantified using an anti-factor Xa assay. However, this method has a relatively narrow analytical concentration range, poor selectivity, and requires an external calibrator. Therefore, the goal of current study was to establish an analytical method for determining plasma levels of apixaban using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). To this end, apixaban was separated using 2.5 mM ammonium formate (pH 3.0) (A) and 100% methanol containing 0.1% formic acid (B) using the gradient method with a Thermo hypersil GOLD column. The mass detector condition was optimized using the electrospray ionization (ESI) positive mode for apixaban quantification. The developed method showed sufficient linearity (coefficient of determination [r² ≥ 0.997]) at calibration curve ranges. The percentage (%) changes in accuracy, precision, and all stability tests were within 15% of the nominal concentration. Apixaban concentration in plasma from healthy volunteers was quantified using the developed method. The mean maximum plasma concentration (C_max) was 371.57 ng/mL, and the median time to achieve the C_max (T_max) was 4 h after administration of 10 mg apixaban alone. Although the results showed low extraction efficiency (~16%), the reproducibility (% change was within 15% of nominal concentration) was reliable. Therefore, the developed method could be used for clinical pharmacokinetic studies.

Phenprocoumon Dose Requirements, Dose Stability and Time in Therapeutic Range in Elderly Patients With CYP2C9 and VKORC1 Polymorphisms

Background

Dose requirements of vitamin K antagonists are associated with CYP2C9 and VKORC1, but, compared to warfarin, less data is available about phenprocoumon. Furthermore, the effects on dose stability and anticoagulation quality are still unclear.

Methods

Aim was to scrutinize phenprocoumon dose requirements, dose stability and anticoagulation quality in association to CYP2C9 and VKORC1 in a natural cohort of elderly primary care patients. As a subgroup within the IDrug study, phenprocoumon treated patients with at least two INR values within three months before enrollment (n = 209) were analyzed concerning average weekly dose, standard deviation of weekly dose (intra-subject variability), constant dose (yes/no), average INR and TTR grouped by CYP2C9 and VKORC1 (and combinations).

Results

Average weekly dose per patient was 14.4 ± 5.3 mg, 11.9 ± 4.0 mg and 11.2 ± 4.3 mg in CYP2C9 wildtypes, *2 and *3 carriers (p < .0001) and 16.0 ± 4.2 mg, 13.3 ± 5.1 mg and 8.0 ± 2.7 mg per week in VKORC1 CC, CT and TT genotypes, respectively (p < .0001). Significant differences concerning intra-subject variability were detected among all groups (p < .0001) with the smallest variability in CYP2C9*3 carriers. TTR medians were 75.4%, 79.4% and 100% in wildtypes, *2 and *3 carriers, respectively (p = 0.0464). The proportion of patients with perfect control was highest among *3 carriers, but this result was not significant (p = 0.0713).

Discussion

Our analyses support the results of previous investigations regarding genotype-associated dose requirements and raise the hypothesis that dose stability and anticoagulation quality may be increased in CYP2C9*3 carriers. However, our data should be treated cautiously due to the small sample size.

Clinical Trial Registration

German Clinical Trials Register, identifier DRKS00006256.

Analysis of Factors That Interrupt With INR Control in the First Anticoagulation Clinic Monitoring Jordanian Patients

Multiple factors such as vitamin K consumption, drug interactions, herbs interactions, disease states, and alcohol intake affect international normalized ratio (INR) values and thus warfarin dosing. These variables have been described in general and for all patients in the literature. In contrast, the factors that affect INR control in a specific population are rarely studied. Being aware of these factors contributes a lot in maintaining an INR control and avoiding the supratherapeutic or subtherapeutic anticoagulation and the associated risks of hemorrhage or thromboembolism. The aim of this study is to recognize the specific population factors in Jordanian patients that interrupt INR control. Such recognition provides clinical pharmacists managing the anti-coagulation clinic (ACC) with necessary tools and predictors of dose adjustment, nontarget INR handling, and points to add on to the educational session. A total of 2788 patients were referred to the first clinical pharmacists managed ACC at Queen Alia Heart Institute—the only official referral hospital for cardiac patients in Jordan—for education and monitoring between November 1, 2013, and November 1, 2016. We evaluated specific population factors that interrupt INR control using a pretested, structured clinical data collection form. The patients were followed up regularly for achieving target INR (TINR). For patients who were not achieving TINR, the possible cause was examined thoroughly by reviewing the patient’s medical file for recent medication intake, comorbidities, and laboratory results. Then the patients or their caregiver were asked direct questions regarding their diet, food supplements, cigarette smoking, shisha smoking, alcohol intake, herbs, and complementary medicine use and compliance, in addition to performing pharmacogenetic testing (polymorphisms of vitamin K–epoxide reductase complex [VKORC1] and cytochrome P450 2C9 [CYP2C9] genes) in special cases. For a total of 2788 patients, 89 488 INR values were included in the study. Of all, 20 365 (22.8%) were non-TINR values, 13 145 (14%) were subtherapeutic, and 7220 (8.1%) were supratherapeutic. All patients included in the study had a non-TINR at least 3 times (n = 65, 2.3%) and as frequent as 50 times (n = 21, 0.8%) during the study period. Non-TINR values ranged from 1 to 11. Serious side effects reported in 7 patients with uncontrolled INR, 6 were bleeding, which required hospitalization (2 upper gastrointestinal [GI] bleeding, 3 nasal bleeding, and 1 eye bleeding), 1 was cerebrovascular accident (CVA thrombolytic). Factors that interrupted INR control in our population, arranged in descending sequence, were concurrent medication use 46.9% (mainly Salicylates and Amiodarone), smoking cigarettes and shisha 17% (represented the most frequent single factor that caused non-TINR in the present study), a nonbalanced dietary vitamin K intake 16.88% caused changes in INR (lower) was related to an increase in the intake of vitamin K-rich food, were noticed to be much more in the spring season in Jordan (end of March and April mainly), herbal supplements 15.02%; Hawthorn (Crataegus, الزعرور) is an herb that lives widely in Jordan, and shockingly we found that it is used very commonly in our ACC patients and corresponded to an elevated INR <8 in 11 patients, and serious bleeding events that required hospitalization in 2 cases), noncompliance 1.49%, comorbid diseases 1%, malabsorption 0.53%, alcohol intake 0.39%, and VKORC1 A/G and CYP2C9 *1*1 genotype 0.15%. The analysis of factors that interrupted with INR control in our patients were both predicted and distinctive; most of these factors were reported previously by other researchers. On the other hand, many of the previously reported factors were not frequently detected in our patients, and the frequency of each of the realized factors was contributed differently to non-TINR in our population. Alarming factors causing non-TINR detected in our study include smoking both cigarettes and shisha, herbal use (Hawthorn and Ginseng), increased intake of vitamin K rich food in the spring season, and concurrent medication use (Salicylates, Amiodarone, Ciprofloxacin, nonsteroidal anti-inflammatory drugs [NSAIDS], Azithromycin, Clarithromycin: although the use of these drugs is mandatory sometimes, it can be replaced by an alternative, eg, antibiotics or monitored closely together with warfarin).

Cold Application on Bruising at the Subcutaneous Heparin Injection Site: A Systematic Review and Meta-Analysis

Despite the documented clinical efficacy, the injection of subcutaneous heparin can be associated with adverse drug reactions including bruising at the injection site. This study sought to systematically assess current evidence regarding the effect of cold application as a fundamental nursing intervention on the occurrence and size of bruising at the injection site in patients receiving subcutaneous heparin. A systematic review and meta-analysis of randomized controlled trials and quasi-experimental studies was performed. Web of Knowledge, PubMed (including MEDLINE), Scopus, Embase, Cochrane library, gray literature, and cross-referencing from reference lists were searched from 2000 to 2019. Quality of selected studies was assessed using the Cochrane risk of bias appraisal tool for randomized controlled trials and the JBI MASTARI appraisal tool for quasi-experimental studies. The search yielded 3,220 articles, but consideration of inclusion criteria led to final selection of 9 articles. The meta-analysis showed that cold application significantly reduced the relative occurrence of bruising at the subcutaneous heparin injection site by 40% (relative risk, 0.60; 95% confidence interval [0.39, 0.91]) and reduced the bruising size (standardized mean difference, -2.78; 95% confidence interval [-4.34, -1.22]). Cold application as a fundamental nursing intervention can be an effective intervention to prevent adverse drug reactions at the injection site in terms of the occurrence and size of bruising in patients receiving subcutaneous heparin.

Evaluation of a Health Information Technology-Enabled Panel Management Platform to Improve Anticoagulation Control in a Low-Income Patient Population: Protocol for a Quasi-Experimental Design

BACKGROUND

Warfarin is one of the most commonly prescribed medications in the United States, and it causes a significant proportion of adverse drug events. Patients taking warfarin fall outside of the recommended therapeutic range 30% of the time, largely because of inadequate laboratory monitoring and dose adjustment. This leads to an increased risk of blood clots or bleeding events. We propose a comparative effectiveness study to examine whether a technology-enabled anticoagulation management program can improve long-term clinical outcomes compared with usual care.

OBJECTIVE

Our proposed intervention is the implementation of an electronic dashboard (integrated into a preexisting electronic health record) and standardized workflow to track patients' laboratory results, identify patients requiring follow-up, and facilitate the use of a validated nomogram for dose adjustment. The primary outcome of this study is the time in therapeutic range (TTR) at 6 months post intervention (a validated metric of anticoagulation quality among patients receiving warfarin).

METHODS

We will employ a pre-post quasi-experimental design with a nonequivalent usual-care comparison site and a difference-in-differences approach to compare the effectiveness of a technology-enabled anticoagulation management program compared with usual care at a large university-affiliated safety-net clinic.

RESULTS

We used a commercially available health information technology (HIT) platform to host a registry of patients on warfarin therapy and create the electronic dashboard for panel management. We developed the intervention with, and for, frontline clinician users, using principles of human-centered design. This study is funded until September 2020 and is approved by the University of California, San Francisco Institutional Review Board until June 22, 2020. We completed data collection in September 2019 and expect to complete our proposed analyses by February 2020.

CONCLUSIONS

We anticipate that the intervention will increase TTR among patients taking warfarin and that the use of this HIT platform will facilitate tracking and monitoring of patients on warfarin, which could enable outreach to those overdue for visits or laboratory monitoring. We will use these findings to iteratively improve the platform in preparation for a larger, multiple-site, pragmatic clinical trial. If successful, our study will demonstrate the integration of HIT platforms into existing electronic health records to improve patient care in real-world clinical settings.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/13835.

Antithrombotic Drugs-Pharmacology and Perspectives

Thrombosis, the localized clotting of blood that affects arterial or venous circulation, is one of the leading causes of death worldwide. Arterial thrombosis is commonly initiated by vascular endothelial injury, while venous thrombosis mainly stems from blood stasis. Despite these differences, platelet adhesion, activation and aggregation, and fibrin formation as a result of coagulation constitute the fundamental processes of thrombus formation. Antithrombotic drugs permitted on the clinical currently can dramatically reduce major adverse cardiovascular events; however, they can also increase the bleeding risk. Discovery of antithrombotic drugs that can effectively prevent thrombosis while sparing bleeding side effects remains unmet medical need. In this chapter, we provide an overview on the pathophysiology of thrombosis, followed by introduction of each class of antithrombotic drugs including their pharmacology, clinical applications and limitations. Practical challenges and future perspectives of antithrombotic drugs are discussed in the last part of this chapter.

Concentrations of Circulating Phylloquinone, but Not Cerebral Menaquinone-4, Are Positively Correlated with a Wide Range of Cognitive Measures: Exploratory Findings in Centenarians

BACKGROUND

Vitamin K (VK) exists in the form of phylloquinone (PK) and menaquinones (MKs). Roles of VK on cognitive health in the elderly are emerging, but there is limited evidence on VK uptake and metabolism in human brain.

OBJECTIVES

The primary objective of this study was to characterize VK distribution in brains of an elderly population with varied cognitive function. In addition, associations among circulating (a biomarker of VK intake) and cerebral VK concentrations and cognition were investigated.

METHODS

Serum or plasma (n = 27) and brain samples from the frontal cortex (FC; n = 46) and the temporal cortex (TC; n = 33) were acquired from 48 decedents (aged 98-107 y; 25 demented and 23 nondemented) enrolled in the Georgia Centenarian Study. Both circulating and brain VK concentrations were measured using HPLC with fluorescence detection. Cognitive assessment was performed within 1 y prior to mortality. Partial correlations between serum/plasma or cerebral VK concentrations and cognitive function were performed, adjusting for covariates and separating by dementia and antithrombotic use.

RESULTS

MK-4 was the predominant vitamer in both FC (mean ± SD = 4.92 ± 2.31 pmol/g, ≥89.15% ± 5.09% of total VK) and TC (4.60 ± 2.11 pmol/g, ≥89.71% ± 4.43% of total VK) regardless of cognitive status. Antithrombotic users had 34.0% and 53.9% lower MK-4 concentrations in FC (P < 0.05) and TC (P < 0.001), respectively. Circulating PK was not correlated with cerebral MK-4 or total VK concentrations. Circulating PK concentrations were significantly associated with a wide range of cognitive measures in nondemented centenarians (P < 0.05). In contrast, cerebral MK-4 concentrations were not associated with cognitive performance, either before or after exclusion of antithrombotic users.

CONCLUSIONS

Circulating VK concentrations are not related to cerebral MK-4 concentrations in centenarians. Cerebral MK-4 concentrations are tightly regulated over a range of VK intakes and cognitive function. Circulating PK may reflect intake of VK-rich foods containing other dietary components beneficial to cognitive health. Further investigation of VK uptake and metabolism in the brain is warranted.

Inhibitory effects of dabigatran etexilate, a direct thrombin inhibitor, on osteoclasts and osteoblasts

INTRODUCTION

Anticoagulants are widely used in orthopedic surgery to decrease the risk of deep vein thrombosis. While significant bone impairment is induced by long-term heparin therapy, little is known about the effects of direct oral anticoagulants (DOACs). Herein, we investigated the effects of dabigatran etexilate (Pradaxa®), a DOAC inhibitor of thrombin, on bone cells using in vitro and ex vivo cell culture models.

MATERIALS AND METHODS

Osteoblasts and osteoclasts exposed to different concentrations of dabigatran etexilate and untreated cells were assayed for cell differentiation and activity. Favorable osteogenic conditions for osteoblasts were tested using titanium with nanotopography (Ti-Nano). In addition, mice treated with a dabigatran etexilate solution had bone marrow cells analyzed for the ability to generate osteoclasts.

RESULTS

Dabigatran etexilate at concentrations of 1 μg/mL and 2 μg/mL did not impact osteoclast or osteoblast viability. The drug inhibited osteoclast differentiation and activity as observed by the reduction of TRAP+ cells, resorption pits and gene and protein expression of cathepsin K. Consistently, osteoclasts from mice treated with dabigatran showed decreased area, resorptive activity, as well as gene and protein expression of cathepsin K. In osteoblast cultures, grown both on polystyrene and Ti-Nano, dabigatran etexilate reduced alkaline phosphatase (ALP) activity, matrix mineralization, gene expression of ALP and osteocalcin.

CONCLUSIONS

Dabigatran etexilate inhibited osteoclast differentiation in ex vivo and in vitro models in a dose-dependent manner. Moreover, the drug reduced osteoblast activity even under optimal osteogenic conditions. This study provides new evidence regarding the negative overall impact of DOACs on bone cells.

Management of two major postoperative bleeding complications after mandible reconstruction with fibula free flap in a patient under chronic warfarin treatment

We present a case of two separated life-threatening postoperative bleeding complications after mandible cancer resection and microsurgical fibula flap in a patient under permanent warfarin treatment. We used fresh frozen plasma, prothrombin complex concentrate to control bleedings. We consider to maintain similar patients in heparin/enoxaparin bridging for 1–2 weeks.

Intracranial calcifications under vitamin K antagonists or direct oral anticoagulants: Results from the French VIKING study in older adults

OBJECTIVES

The use of vitamin K antagonists (VKA) is associated with the onset of vascular and soft-tissue calcifications. Whether there are more intracranial calcifications under VKA remains unclear. The objective of this study was to determine whether the regular use of VKA in older adults was associated with an increased burden of intracranial calcifications compared with the use of direct oral anticoagulant (DOA).

STUDY DESIGN

Nineteen patients aged 70 years or more using VKA for more than 3 months and 19 controls (matched for age, gender and indication for anticoagulation) using DOA for more than 3 months were consecutively included in this study.

MAIN OUTCOMES MEASURES

The burden of intracranial calcifications was graded by an experienced neuroradiologist from 0 (no burden) to 3 (high burden) according to the quantity, size, intensity and confluence of calcifications on computed tomography scan of the brain. Age, gender, frontal assessment battery (FAB) score, hypertension, dyslipidaemia, carotid artery stenosis, kidney failure and indication for anticoagulation were investigated as potential confounders.

RESULTS

The 19 patients using VKA (median[IQR], 84years[7]; 10females) exhibited a greater burden of falcian calcifications than the 19 controls using DOA (respectively, 2[1] versus 1[2], P = 0.025). Overall, we found that using VKA was directly associated with the global burden of intracranial calcifications (β = 1.54, P = 0.049). No correlation was found with calcifications in sites other than the falx cerebri.

CONCLUSIONS

The use of VKA was associated with a greater burden of intracranial calcifications compared with the use of DOA, specifically in the falx cerebri. This finding may explain part of the neurocognitive morbidity met with VKA.

Effects of Polymorphisms in Myc-Related Genes on Bleeding Complications in Patients with Stable Warfarin Responses

Objectives

This study aimed to identify the possible effects of Myc and 8q24 polymorphisms on bleeding complications in patients who maintained international normalized ratio (INR) of 2.0-3.0 with warfarin therapy after cardiac valve replacement.

Methods

Twenty-five single nucleotide polymorphisms were analyzed, including VKORC1, CYP2C9, Myc, and 8q24. Univariate and multivariate analyses were conducted to evaluate the associations between genetic polymorphisms and bleeding complications. Attributable risk and the number needed to genotype (NNG) were also calculated to evaluate the potential clinical value of genotyping.

Results

We included 142 patients, among whom 21 experienced bleeding complications. Multivariate models showed that patients carrying the CC genotype of rs6983561 and the A allele of rs13281615 at 8q24 had 27.6- and 10.0-fold higher bleeding complications, compared with patients with the A allele and the GG genotype, respectively. For rs6983561, the attributable risk and NNG were 96.4% and 36.8, respectively, whereas, for rs13281615, the attributable risk and NNG were 90.0% and 8.3, respectively. Atrial fibrillation was associated with a 5.5-fold increased risk of bleeding complications. The AUROC value was 0.761 (95% CI 0.659-0.863, p<0.001), and the Hosmer–Lemeshow test showed that the fitness of the multivariate analysis model was satisfactory (χ²=0.846; 3 degrees of freedom; p=0.838).

Conclusions

Bleeding complications during warfarin therapy were associated with 8q24 polymorphisms and atrial fibrillation in patients with mechanical heart valves.

Group-based Trajectory Models to Assess Quality of INR Control and Its Association With Clinical Outcomes

Supplemental Digital Content is available in the text.

The Time in Therapeutic Range (TTR) is the gold-standard measure used to assess the quality of oral anticoagulation with vitamin K antagonists. However, TTR is a static measure, and International Normalized Ratio (INR) control is a dynamic process. Group-based Trajectory Models (GBTM) can address this dynamic nature by classifying patients into different trajectories of INR control over time.

Ischemic Stroke and Systemic Embolism in Warfarin Users With Atrial Fibrillation or Heart Valve Replacement Exposed to Dicloxacillin or Flucloxacillin

The antibiotics dicloxacillin and flucloxacillin induce cytochrome P450-dependent metabolism of warfarin. We explored the influence of these drug-drug interactions on the clinical effectiveness of warfarin therapy due to atrial fibrillation or heart valve replacement. Using the population-based Danish registers, we performed a propensity-score matched cohort study including around 50,000 episodes of dicloxacillin/flucloxacillin matched to phenoxymethylpenicillin and to no antibiotic, respectively. We estimated hazard ratios (HRs) with 95% confidence intervals (CIs) by comparing 21-day (days 7-28) risks of ischemic stroke/systemic embolism (SE) following initiation of each exposure. When compared with phenoxymethylpenicillin, dicloxacillin/flucloxacillin was associated with an HR of ischemic stroke/SE of 2.09 (95% CI 1.51-2.90; strongest for dicloxacillin (HR 2.17; 95% CI 1.56-3.02)). Use of an untreated comparator strengthened the association (HR 2.84; 95% CI 1.97-4.09). Dicloxacillin should be used with caution in patients receiving warfarin. This may also apply to flucloxacillin; however, more data on the risks associated with flucloxacillin exposure during warfarin therapy are needed.

Cost-Effectiveness of Extended Thromboprophylaxis in Patients Undergoing Colorectal Surgery from a Canadian Health Care System Perspective

BACKGROUND

There is increasing evidence to support extended thromboprophylaxis after colorectal surgery to minimize the incidence of postdischarge venous thromboembolic events. However, the absolute number of events is small, and extended thromboprophylaxis requires significant resources from the health care system.

OBJECTIVE

This study aimed to determine the cost-effectiveness of extended thromboprophylaxis in patients undergoing colorectal surgery for malignancy or IBD.

DESIGN

An individualized patient microsimulation model (1,000,000 patients; 1-month cycle length) comparing extended thromboprophylaxis (28-day course of enoxaparin) to standard management (inpatient administration only) after colorectal surgery was constructed.

SETTINGS

The sources for this study were The American College of Surgeons National Surgical Quality Improvement Project Participant User File and literature searches.

OUTCOMES

Costs (Canadian dollars), quality-adjusted life-years, and venous thromboembolism-related deaths prevented over a 1-year time horizon starting with hospital discharge were determined. The results were stratified by malignancy or IBD.

RESULTS

In patients with malignancy, extended prophylaxis was associated with higher costs (+113$; 95% CI, 102-123), but increased quality-adjusted life-years (+0.05; 95% CI, 0.04-0.06), resulting in an incremental cost-effectiveness ratio of 2473$/quality-adjusted life-year. For IBD, extended prophylaxis also had higher costs (+116$; 95% CI, 109-123), more quality-adjusted life-years (+0.05; 95% CI, 0.04-0.06), and an incremental cost-effectiveness ratio of 2475$/quality-adjusted life-year. Extended prophylaxis prevented 16 (95% CI, 4-27) venous thromboembolism-related deaths per 100,000 patients and 22 (95% CI, 6-38) for malignancy and IBD. There was a 99.7% probability of cost-effectiveness at a willingness-to-pay threshold of 50,000$/quality-adjusted life-year. To account for statistical uncertainty around variables, sensitivity analysis was performed and found that extended prophylaxis is associated with lower overall costs when the incidence of postdischarge venous thromboembolic events reaches 1.8%.

LIMITATIONS

Significant differences in health care systems may affect the generalizability of our results.

CONCLUSIONS

Despite the rarity of venous thromboembolic events, extended thromboprophylaxis is a cost-effective strategy. See Video Abstract at http://links.lww.com/DCR/A976. COSTO-EFECTIVIDAD DE LA TROMBOPROFILAXIS EXTENDIDA EN PACIENTES SOMETIDOS A CIRUGÍA COLORRECTAL DESDE UNA PERSPECTIVA DEL SISTEMA DE SALUD CANADIENSE:: Cada vez hay más pruebas que apoyen la tromboprofilaxis extendida después de la cirugía colorrectal para minimizar la incidencia de eventos tromboembólicos venosos después del alta hospitalaria. Sin embargo, el número absoluto de eventos es pequeño y la tromboprofilaxis extendida requiere recursos significativos del sistema médico.Determinar la rentabilidad (relación costo-efectividad) de la tromboprofilaxis extendida en pacientes sometidos a cirugía colorrectal por neoplasia maligna o enfermedad inflamatoria intestinal.Un modelo de microsimulación de paciente individualizado (1,000,000 de pacientes; ciclo de 1 mes) que compara la tromboprofilaxis extendida (curso de enoxaparina de 28 días) con el tratamiento estándar (solo para pacientes hospitalizados) después de la cirugía colorrectal.Archivo de usuario participante del Proyecto de Mejoramiento de la Calidad Quirúrgica del Colegio Nacional de Cirujanos Americanos (ACS-NSQIP) y búsquedas bibliográficas.Costos (en dólares Canadienses), años de vida ajustados por la calidad y muertes relacionadas con el tromboembolismo venoso prevenidas en un horizonte temporal de 1 año a partir del alta hospitalaria. Los resultados fueron estratificados por malignidad o enfermedad inflamatoria intestinal.En pacientes con neoplasias malignas, la profilaxis extendida se asoció con costos más altos (+113 $; IC del 95%, 102-123), pero con un aumento de la calidad de vida ajustada por años de vida (+0.05; IC del 95%, 0.04-0.06), lo que resultó en un incremento de relación costo-efectividad de 2473 $/año de vida ajustado por calidad. Para la enfermedad inflamatoria intestinal, la profilaxis extendida también tuvo costos más altos (+116 $; 95% IC, 109-123), más años de vida ajustados por calidad (+0.05; 95% IC, 0.04-0.06) y una relación costo-efectividad incremental de 2475 $/año de vida ajustado por calidad. La profilaxis prolongada evitó 16 (95% IC, 4-27) muertes relacionadas con tromboembolismo venoso por cada 100,000 pacientes y 22 (95% IC, 6-38) por malignidad y enfermedad inflamatoria intestinal, respectivamente. Hubo un 99.7% de probabilidad de costo-efectividad en un límite de disposición a pagar de 50,000 $/año de vida ajustado por calidad. Para tener en cuenta la incertidumbre estadística en torno a los variables, se realizó un análisis de sensibilidad y se encontró que la profilaxis extendida se asocia con menores costos generales cuando la incidencia de eventos tromboembólicos venosos después del alta hospitalaria alcanza 1.8%.Las diferencias significativas en los sistemas de salud pueden afectar la generalización de nuestros resultados.A pesar de la escasez de eventos tromboembólicos venosos, la tromboprofilaxis extendida es una estrategia rentable. Vea el video del resumen en http://links.lww.com/DCR/A976.

Periprocedural Outcomes of Direct Oral Anticoagulants Versus Warfarin in Nonvalvular Atrial Fibrillation

BACKGROUND

Direct oral anticoagulants (DOACs) are surpassing warfarin as the anticoagulant of choice for stroke prevention in nonvalvular atrial fibrillation. DOAC outcomes in elective periprocedural settings have not been well elucidated and remain a source of concern for clinicians. The aim of this meta-analysis was to evaluate the periprocedural safety and efficacy of DOACs versus warfarin in patients with nonvalvular atrial fibrillation.

METHODS

We reviewed the literature for data from phase III randomized controlled trials comparing DOACs with warfarin in the periprocedural period among patients with nonvalvular atrial fibrillation. Substudies from 4 trials (RE-LY [Randomized Evaluation of Long-Term Anticoagulation Therapy], ROCKET AF [Rivaroxaban Once Daily Oral Direct Factor Xa Inhibitor Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation], ARISTOTLE [Apixaban for the Prevention of Stroke in Subjects With Atrial Fibrillation], and ENGAGE-AF [Effective Anticoagulation With Factor xA Next Generation in Atrial Fibrillation]) were included in the meta-analysis. DOACs as a group and warfarin were compared in terms of the 30-day pooled risk for stroke/systemic embolism, major bleeding, and death, according to whether the study drug was interrupted or not periprocedurally. The overall relative risk (RR) was estimated with a random-effects model. The I² test was used to assess heterogeneity in RR among the studies.

RESULTS

In the uninterrupted anticoagulant strategy, there were no differences in the rates of stroke/systemic embolism (pooled risk, 0.6% [29 events/4519 procedures] versus 1.1% [31/2971]; RR, 0.70; 95% confidence interval [CI], 0.41-1.18) and death (1.4% versus 1.8%; RR, 0.77; 95% CI, 0.53-1.12) between DOACs and warfarin and significantly fewer major bleeding events (2.0% versus 3.3%; RR, 0.62; 95% CI, 0.47-0.82) with DOACs compared to warfarin. Under an interrupted strategy, there was no significant difference between DOACs versus warfarin for stroke/systemic embolism (0.4% [41/9260] versus 0.5% [31/7168]; RR, 0.95; 95% CI, 0.59-1.55), major bleeding (2.1% versus 2.0%; RR, 1.05; 95% CI, 0.85-1.30), and death (0.7% versus 0.6%; RR, 1.24; 95% CI, 0.76-2.04). The studies were homogeneous ( I²=0.0%) for all calculated pooled associations except for the RR of death in the interrupted strategy ( I²=26.3%).

CONCLUSIONS

The short-term safety and efficacy of DOACs and warfarin are not different in patients with nonvalvular atrial fibrillation periprocedurally. Under an uninterrupted anticoagulation strategy, DOACs are associated with a 38% lower risk of major bleeding compared with warfarin.

Prophylactic prosthetic wrapping for vascular anastomosis in patients with Behçet's aortic aneurysms: an experience from a resource-challenged setting

BACKGROUND

The objectives of the current study were to evaluate our technical and clinical results of surgical treatment of infrarenal Behçet's abdominal aortic aneurysm (AAA). In addition to the prosthetic wrapping of the constructed anastomosis as a prophylactic measure for patients with vasculo-Behçet's disease, together with the administration of per- and postoperative immunosuppressive therapy.

METHODS

A single-center retrospective case series included 16 patients with vasculo-Behçet's AAA who treated with open surgical repair, between January 2005 and December 2013. The administration of immunosuppressive treatment was done preoperatively to achieve complete remission of the disease activity before starting the surgical repair. Patients' data were retrieved and analyzed emphasizing the diagnostic procedures, the used surgical techniques, and suitable graft selection, as well as, graft-related complications. The patients were followed up for one month to a maximum of 72 months. The median follow-up period was 24.83±9.4 months.

RESULTS

This study included 16 patients, 10 (63%) males, and 6 (37%) females, with the median age of (30.50 years, range: 21-37 years). Moreover, all patients were anticoagulated and discharged on warfarin and aspirin therapy. All surgical procedures were done on an elective basis except for only one emergency laparotomy, which was performed for a life-threatening ruptured aneurysm. The vascular anastomoses were performed using either interposition tube graft (for isolated AAA), or Y-shaped graft (for concomitant aorto-iliac aneurysms). Furthermore, prophylactic prosthetic wrapping was applied encircling the graft to the host artery. In addition, all patients received systemic immunosuppressive therapy post-surgical intervention to prevent anastomotic site complications. Technical success was obtained in 100% of cases. Moreover, the patients were followed up for a period of 12-72 months. Two anastomotic pseudoaneurysms were developed postoperatively. More interesting is that both were infected (one low-virulent that was conservatively treated and one overt that was surgically repaired). Furthermore, there was no aneurysm-related mortality.

CONCLUSIONS

Prophylactic prosthetic wrapping of vascular anastomosis in patients with Behçet's AAA in resource-challenged settings, where the proximal anastomoses were all end-to-end with wrapping, is an affordable, simple, reliable, and feasible technique, and commonly associated with a lower incidence of anastomotic site false aneurysms and different complications related to the implanted graft, where endovascular procedures might not be applicable. Moreover, the proper preoperative medical preparation for controlling the activity of Behçet's disease, with the administration of immunosuppressive agents, followed by immediate postoperative therapy, may have a good impact on the operative technical success and the prevention of the development of serious postoperative complications; especially anastomotic pseudoaneurysms (which may be complicated by fatal hemorrhage), as well as other graft-related complications.

Consensus in cardiology on non-vitamin-K oral anticoagulants for patients with atrial fibrillation

Introduction: Non-vitamin-K oral anticoagulants (NOACs) are known to have advantages over vitamin K antagonists (VKAs) for patients with atrial fibrillation (AF). However, more than half of patients are still treated with VKAs. The absence of direct comparisons amongst NOACs and the insufficient evidence in some clinical situations could explain, at least in part, this predominance of VKAs. The aims of our study were: 1) to analyze the opinion of an expert panel on the role of NOACs in different clinical scenarios; 2) to elaborate specific consensus recommendations for the management of NOACs for each one of these situations.Patients and methods: An online survey was created covering distinct aspects of the use of oral anticoagulants in various clinical settings. A two-round modified Delphi approach was used.Results: Forty-eight experts responded to the survey. Consensus was reached on 58% (48/83) of the items. The panelists concluded that the term non-valvular AF should be avoided. In most clinical settings NOACs were preferred over VKAs. Once daily NOACs were preferred in elderly patients to improve therapeutic compliance and, in those over the age of 85, edoxaban could be the best choice. Edoxaban and apixaban were the favorites for patients with AF and moderate chronic kidney disease (CKD). In the case of patients on triple antithrombotic therapy due to AF and acute coronary syndrome (ACS) the lowest effective NOAC dose should be used.Conclusion: Our study emphasizes that there are several clinical circumstances in patients with AF requiring complex decisions about anticoagulation treatment and offers some recommendations based on the consensus reached by an expert panel.

Croatian Society of Medical Biochemistry and Laboratory Medicine: National recommendations for blood collection, processing, performance and reporting of results for coagulation screening assays prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen and D-dimer

A modern diagnostic laboratory offers wide spectrum of coagulation assays utilized in the diagnosis and management of patients with haemostatic disorders, preoperative screening and anticoagulation therapy monitoring. The recent survey conducted among Croatian medical biochemistry and transfusion laboratories showed the existence of different practice policies in particular phases of laboratory process during coagulation testing and highlighted areas that need improvement. Lack of assay standardization together with non-harmonized test results between different measurement methods, can potentially lead to incorrect decisions in patient’s treatment. Consequently, patient safety could be compromised. Therefore, recommended procedures related to preanalytical, analytical and postanalytical phases of prothrombin time, activated partial thromboplastin time, thrombin time, fibrinogen and D-dimer testing are provided in this review, aiming to help laboratories to generate accurate and reliable test results.

Association between HNF4A mutations and bleeding complications in patients with stable international normalized ratio

OBJECTIVES

This study aimed to determine the association between hepatocyte nuclear factor 4 alpha (HNF4A) polymorphisms and bleeding complications in patients on warfarin with international normalized ratios between 2.0 and 3.0 after cardiac valve replacement.

METHODS

Nineteen single nucleotide polymorphisms of HNF4A in addition to VKORC1 rs9934438 and CYP2C9 rs1057910 were analyzed. Univariate and multivariate analyses were conducted to evaluate associations between genetic polymorphisms and bleeding risk. Attributable risk and number needed to genotype (NNG) were calculated to assess clinical value of genotyping.

RESULTS

Of 142 patients, 21 experienced bleeding complications. Multivariate logistic regression analysis was conducted using factors with P <0.1 in univariate analysis. Multivariate analysis showed that patients with the CC genotype of rs6130615 had an 8.4-fold increased risk of bleeding, compared with patients with the T allele. Attributable risk and NNG were 88.1% and 32.2, respectively. Patients with the TT genotype of rs3212191 had a 3.8-fold increased risk of bleeding, compared with C allele carriers, while patients with variant-type homozygotes for rs1884613 showed an 8.7-fold higher bleeding complication than C allele carriers. The attributable risk/NNG of rs3212191 and rs1884613 were 73.4%/17.6 and 88.5%/22.8, respectively. Among comorbidities, atrial fibrillation was the only significant risk factor for bleeding complications.

CONCLUSION

Bleeding complications during warfarin therapy in patients with mechanical heart valves were associated with HNF4A polymorphisms and atrial fibrillation.