A Practical Review of the Emerging Direct Anticoagulants, Laboratory Monitoring, and Reversal Agents

The effect of anticoagulation therapy on the surgical outcomes of minimally invasive major gastrointestinal surgery

BACKGROUND

The surgical outcomes of minimally invasive surgery (MIS) for gastrointestinal (GI) cancers in patients receiving anticoagulation therapy (ACT) are unknown. We investigated the effect of ACT on the surgical outcomes of minimally invasive major GI surgery, with a particular focus on postoperative bleeding and thromboembolic complications.

METHODS

A total of consecutive 1290 patients undergoing elective minimally invasive (laparoscopic and robotic) major GI surgery (esophagogastric and colorectal resection for malignancy) between 2014 and 2023 were enrolled. The patients were divided into three groups: patients without receiving anticoagulation therapy (non-ACT, n = 1076), patients receiving direct oral anticoagulants (DOAC, n = 144), and patients receiving warfarin (WF, n = 70). Outcome variables were compared between the groups and the risk factors of postoperative bleeding complications were assessed using logistic multivariate analysis.

RESULTS

The overall rate of thromboembolic complication was 0.5%, and the operative mortality was zero in the whole cohort. The incidences of postoperative bleeding in the non-ACT, DOAC, and WF groups were 1.0%, 6.9% and 11.4%, respectively (P < 0.001). Among 8 DOAC-received patients with postoperative GI bleeding, 75% of cases occurred on postoperative day 5 or later. Multivariate analysis showed DOAC (odds ratio = 5.420, P < 0.001) and perioperative heparinization (odds ratio = 3.770, P = 0.048) were significant risk factors for major postoperative bleeding.

CONCLUSIONS

Although minimally invasive major GI surgery can be safely performed in patients receiving ACT, attention should be paid for the occurrence of delayed GI bleeding especially in the DOAC-received patients. Patients treated with DOAC or perioperative heparinization still represent a challenging group in the present cohort, and need to be carefully managed.

Apixaban anti-Xa levels in clinical practice: A case report

Apixaban is a widely used direct oral anticoagulant that is recommended over warfarin therapy for many clinical indications. In patients with atrial fibrillation, dose reductions are recommended for patients with advanced age (≥80 years), low weight (≤60 kg) or elevated serum creatinine (≥1.5 mg/dL), but there is no routine laboratory monitoring necessary for long term-use. Furthermore, apixaban dose reductions due to renal dysfunction are not recommended when treating acute venous thromboembolism. Apixaban-calibrated anti-Xa assays are readily available at some medical centres, and they may be of clinical utility in certain circumstances such as in patients with renal insufficiency, medication adherence assessment, periprocedural planning, extremes in body weight and advanced age. Here, we describe the case of an elderly patient with chronic kidney disease taking apixaban for acute pulmonary embolism. The patient had an unanticipated prolonged apixaban half-life, with detectable apixaban-calibrated anti-Xa levels for >10 days after the last administered dose, which delayed a necessary surgical intervention by >1 week. This case is an example of appropriately using apixaban-calibrated anti-Xa levels to guide therapeutic decision making in perioperative planning.

Efficacy and safety of direct oral anticoagulants versus warfarin in the treatment of cerebral venous sinus thrombosis

BACKGROUND

Given the evolving application and promising outcomes of direct oral anticoagulants (DOACs) in various thromboembolic conditions, we aimed to compare the efficacy and safety of DOACs with warfarin in the post-acute treatment of cerebral venous sinus thrombosis (CVST) using clinical and radiological parameters.

METHODS

A total of 140 CVST patients were enrolled, with 95 receiving warfarin and 45 receiving DOACs as post-acute treatment. Clinical and imaging parameters of the patients in follow-up visits were investigated, including the last modified Rankin Scale (mRS), venous thromboembolic events, CVST recurrence, mortality rate, recanalization status, and hemorrhagic events, to compare the efficacy and safety of treatment between the two groups.

RESULTS

At baseline, patients' assessments using two prognostic scores, ISCVT-RS and IN-REvASC, revealed that there was no statistically significant difference in the distribution of prognostic risk categories between the warfarin and DOACs groups. Following acute therapy, patients in the warfarin and DOACs groups were followed up for the median of 359 and 325 days, respectively. Analysis to compare the efficacy of warfarin and DOACs revealed no significant difference in last mRS scores, CVST recurrence rate, venous thromboembolic events, and recanalization status between the two groups. Additionally, there was no statistically significant difference in the risk of hemorrhagic events between warfarin and DOACs groups.

CONCLUSION

Our findings show that DOACs have comparable safety and efficacy in the post-acute treatment of CVST patients; however, large-scale randomized controlled trials are required to validate our findings.

A functional RNA-origami as direct thrombin inhibitor with fast-acting and specific single-molecule reversal agents in vivo model

Injectable anticoagulants are widely used in medical procedures to prevent unwanted blood clotting. However, many lack safe, effective reversal agents. Here, we present new data on a previously described RNA origami-based, direct thrombin inhibitor (HEX01). We describe a new, fast-acting, specific, single-molecule reversal agent (antidote) and present in vivo data for the first time, including efficacy, reversibility, preliminary safety, and initial biodistribution studies. HEX01 contains multiple thrombin-binding aptamers appended on an RNA origami. It exhibits excellent anticoagulation activity in vitro and in vivo. The new single-molecule, DNA antidote (HEX02) reverses anticoagulation activity of HEX01 in human plasma within 30 s in vitro and functions effectively in a murine liver laceration model. Biodistribution studies of HEX01 in whole mice using ex vivo imaging show accumulation mainly in the liver over 24 h and with 10-fold lower concentrations in the kidneys. Additionally, we show that the HEX01/HEX02 system is non-cytotoxic to epithelial cell lines and non-hemolytic in vitro. Furthermore, we found no serum cytokine response to HEX01/HEX02 in a murine model. HEX01 and HEX02 represent a safe and effective coagulation control system with a fast-acting, specific reversal agent showing promise for potential drug development.

Dabigatran: Clinical correlation of drug and its dose with risk of stroke and bleeding

Background

Dabigatran is the first oral direct thrombin inhibitor which is endorsed by Food and Drug Administration in the prevention of embolic events in patients with nonvalvular atrial fibrillation. Suitable dose of the drug for the patient is selected based on CHA2DS2-VASc score and HAS-BLED score.

Aim

To determine and compare the risk of occurrence of stroke and bleeding after the initiation of dabigatran therapy in patients prescribed with this drug.

Methods

Patients with more than 18 years who were prescribed with dabigatran during 2017-2019 in a tertiary care hospital were selected for the study. Most of the patient's prescriptions contained an antiplatelet, so a comparison was made between the clinical outcomes of patients given with dabigatran alone and dabigatran with an antiplatelet because antiplatelet can have effects on the safety as well as efficacy profile of dabigatran.

Results

Out of 75 patients enrolled in the study, 42 patients were in the dabigatran with the antiplatelet group and 33 were in the dabigatran alone group. In both the groups, there was a significant reduction in CHA2DS2-VASc score, i.e., 2.58 ± 1.32-1.94 ± 1.21 in dabigatran-treated patients within 6 months, and the score was lowered from 3.76 ± 1.22 to 2.92 ± 1.22 in other groups. The mean value of the HAS-BLED score of dabigatran was reduced from 1.15 ± 0.83 to 0.84 ± 0.78 and that of dabigatran with antiplatelet group from 2.10 ± 0.94 to 1.74 ± 0.92.

Conclusion

It was observed that within 6 months, both the treatment groups showed a reduction in the risk scores. The dabigatran group had lower background risks of stroke and bleeding in comparison to the dabigatran plus antiplatelet group.

A comparison of front-line oral anticoagulants for the treatment of non-valvular atrial fibrillation: Effectiveness and safety of direct oral anticoagulants in the FANTASIIA registry

INTRODUCTION

For a long time, vitamin K antagonists (VKA) were the only oral anticoagulation therapy available to reduce adverse events in atrial fibrillation (AF) patients. Direct-acting oral anticoagulants (DOAC) are at least as effective and safe as VKA with few drug interactions, rapid onset and short half-life. Four DOACs, dabigatran, apixaban, rivaroxaban and edoxaban have demonstrated efficacy and safety for treatment in AF patients.

AREAS COVERED

The purpose of this review article is to analyze the current evidence in clinical trials and in real-world populations and performed a new analysis with the estimated effect of those DOACs over the VKA population from the FANTASIIA registry. We present in this manuscript original data analysis from FANTASIIA population as well as data obtained through a search of PubMed for the clinical trials comparing DOAC in the main randomized trials of each DOAC and observational data of the real-world effects of DOACs compared to VKAs.

EXPERT OPINION

In the absence of randomized, controlled head-to-head comparisons between DOACs, high-quality observational data can provide useful information on the comparative effectiveness of DOACs. Current clinical guidelines recommend the management of oral anticoagulation in AF patients with DOACs over VKA for stroke prevention; however, many guidelines generally do not suggest a specific DOAC choice in clinical practice. The revised evidence in this manuscript and our real experience reflects that apixaban and dabigatran show the best efficacy and safety profile.

Engineering a "three-in-one" hirudin prodrug to reduce bleeding risk: A proof-of-concept study

An ideal anticoagulant should have at least three properties including targeted delivery to the thrombosis site, local activation or releasing to centralize the anti-thrombosis effects and thus reduce the bleeding risks, and long persistence in circulation to avoid repeated administration. In the present study, we sought to test a "three-in-one" strategy to design new protein anticoagulants. Based on these criteria, we constructed two hirudin prodrugs, R824-HV-ABD and ABD-HV-R824. The R824 peptide can bind phosphatidylserine on the surface of the procoagulant platelets and thus guide the prodrug to the thrombosis sites; albumin-binding domain (ABDs) can bind the prodrug to albumin, and thereby increase its persistence in circulation; the hirudin (HV) core in the prodrug is flanked by factor Xa recognition sites, thus factor Xa at the thrombosis site can cleave the fusion proteins and release the activated hirudin locally. Hirudin prodrugs were able to bind with procoagulant platelets and human serum albumin in vitro with high affinity, targeted concentrated and prevented the formation of occlusive thrombi in rat carotid artery injury model. Their effective time was significantly extended compared to native hirudin, and R824-HV-ABD showed a significantly improved half-life of about 24 h in rats. The bleeding time of prodrug-treated mice was much shorter than that of hirudin-treated mice. The results from the proof-of-concept studies, for the first time, demonstrate that "three-in-one" prodrug strategy may be a good solution for protein or peptide anticoagulants to reduce their bleeding risks.

Bone density and quality in patients treated with direct-acting oral anticoagulants versus warfarin

INTRODUCTION

Direct-acting oral anticoagulants (DOACs) are therapeutic alternatives to warfarin that act independently of vitamin K, thus not affecting bone matrix formation. The aim of this study was to compare bone mineral density (BMD) and microarchitecture in patients treated with DOACs versus warfarin.

METHODS

Cross-sectional, observational study in patients using oral anticoagulants for >1 year and a paired control group (CG). Based on the type of anticoagulant used, the patients were grouped into a DOAC (DOACG) or warfarin (WG) group. All patients filled out a questionnaire and underwent BMD evaluation and trabecular bone score (TBS) measurement.

RESULTS

In all, 150 patients were included (50 patients in each group). The mean age was 60.49 ± 7.48 years, and most participants were men (64%). The most frequent comorbidities were hypertension, dyslipidemia, and hyperglycemia (comparison between groups p > 0.05). Low bone mass was diagnosed in 42%, 50%, and 66% of the patients in the CG, DOACG, and WG, respectively (p = 0.012). On logistic regression analysis, BMD was associated with body mass index (BMI; odds ratio [OR] 0.846, 95% confidence interval [CI] 0.763-0.926, p = 0.001), creatinine level (OR 0.024, 95%CI 0.001-0.434, p = 0.017), and TBS value (OR 17.777, 95%CI 4.526-96.903, p = 0.000). The mean TBS decreased progressively from the CG to the DOACG and WG (1.328 ± 0.112, 1.264 ± 0.138, and 1.203 ± 0.112, respectively, p < 0.001). On multivariate linear regression, negative predictors of TBS included warfarin use (-0.06, 95%CI -0.11 to -0.02, p = 0.006), BMI (-0.01, 95%CI -0.01 to -0.00, p < 0.001), and hyperglycemia (-0.07, 95%CI -0.11 to -0.03, p = 0.003), while positive predictors were an active IPAQ classification (0.06, 95%CI 0.01-0.11, p = 0.029) and family history of hip fracture (0.07, 95%CI 0.01-0.14, p = 0.029).

CONCLUSION

Patients using anticoagulants have lower BMD and TBS values compared with controls. This negative effect on bone was more pronounced with warfarin, but was also seen with DOACs.

Oral Anticoagulants in Atrial Fibrillation Patients With Recent Stroke Who Are Dependent on the Daily Help of Others

BACKGROUND AND PURPOSE

Data on the effectiveness and safety of direct oral anticoagulants (DOACs) versus vitamin K antagonists (VKAs) in patients with stroke attributable to atrial fibrillation (AF) who were dependent on the daily help of others at hospital discharge are scarce.

METHODS

Based on prospectively obtained data from the observational Novel-Oral-Anticoagulants-in-Ischemic-Stroke-Patients-longterm registry from Basel, Switzerland, we compared the occurrence of the primary outcome-the composite of recurrent ischemic stroke, major bleeding, and all-cause death-among consecutive patients with AF-stroke treated with either VKAs or DOACs between patients dependent (defined as modified Rankin Scale score, 3-5) and patients independent at discharge. We used simple, adjusted, and weighted Cox proportional hazards regression to account for potential confounders.

RESULTS

We analyzed 801 patients (median age 80 years, 46% female), of whom 391 (49%) were dependent at discharge and 680 (85%) received DOACs. Over a total follow-up of 1216 patient-years, DOAC- compared to VKA-treated patients had a lower hazard for the composite outcome (hazard ratio [HR], 0.58 [95% CI, 0.42-0.81]), as did independent compared to dependent patients (HR, 0.54 [95% CI, 0.40-0.71]). There was no evidence that the effect of anticoagulant type (DOAC versus VKA) on the hazard for the composite outcome differed between dependent (HR_dependent, 0.68 [95% CI, 0.45-1.01]) and independent patients (HR_independent, 0.44 [95% CI, 0.26-0.75]) in the simple model (P_interaction=0.212). Adjusted (HR_dependent, 0.74 [95% CI, 0.49-1.11] and HR_independent, 0.51 [95% CI, 0.30-0.87]; P_interaction=0.284) and weighted models (HR_dependent, 0.79 [95% CI, 0.48-1.31] and HR_independent, 0.46 [95% CI, 0.26-0.81]; P_interaction=0.163) yielded concordant results. Secondary analyses focusing on the individual components of the composite outcome were consistent to the primary analyses.

CONCLUSIONS

The benefits of DOACs in patients with atrial fibrillation with a recent stroke were maintained among patients who were dependent on the help of others at discharge.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03826927.

Identification of the functional food ingredients with antithrombotic properties via virtual screen and experimental studies

Thrombin is a key therapeutic target protein of thrombosis. To date, massive studies have focused on the exploration of antithrombotic compounds. Here we capitalize on molecular docking, molecular simulations and spectroscopic experiments for virtually screening natural products that can inhibit thrombin and elucidating their interaction mechanism. Six compounds are screened from a natural product database by a cross-analysis based on two semi-flexible molecular docking methods. We show that four compounds can effectively inhibit thrombin and Calceolarioside B is the most competitive one based on enzyme inhibition experiments. Moreover, the binding free energies of these compounds with thrombin exhibit a consistent rank trend with their enzyme inhibition assay results. In addition, the Van der Waals is the main force to drive the interaction between the ligands and the receptor, which can be deduced from the fluorescence spectral results. This work provides a new insight into the development of antithrombotic natural compounds.

Direct Oral Anticoagulants: From Randomized Clinical Trials to Real-World Clinical Practice

Direct oral anticoagulants (DOACs) are a more manageable alternative than vitamin K antagonists (VKAs) to prevent stroke in patients with nonvalvular atrial fibrillation and to prevent and treat venous thromboembolism. Despite their widespread use in clinical practice, there are still some unresolved issues on optimizing their use in particular clinical settings. Herein, we reviewed the current clinical evidence on uses of DOACs from pharmacology and clinical indications to safety and practical issues such as drugs and food interactions. Dabigatran is the DOAC most affected by interactions with drugs and food, although all DOACs demonstrate a favorable pharmacokinetic profile. Management issues associated with perioperative procedures, bleeding treatment, and special populations (pregnancy, renal and hepatic impairment, elderly, and oncologic patients) have been discussed. Literature evidence shows that DOACs are at least as effective as VKAs, with a favorable safety profile; data are particularly encouraging in using low doses of edoxaban in elderly patients, and edoxaban and rivaroxaban in the treatment of venous thromboembolism in oncologic patients. In the next year, DOAC clinical indications are likely to be further extended.

Portal vein thrombosis: A concise review (Review)

Portal vein thrombosis (PVT) is a frequent complication in cirrhotic patients, but it may also exist as a basic vascular condition even without any liver damage. Local and systemic factors play a significant role in the pathogenesis of PVT; yet, in practice, more than one factor may be identified. PVT can be considered a result of liver fibrosis and hepatic insufficiency. The JAK2 mutation has been accepted as a factor producing PVT. In general, the anticoagulants are recommended but this therapy should be used carefully in treating patients that associate coagulopathy or thrombocytopenia and esophageal varices. Acute PVT without bowel infarction has a good prognosis. In liver cirrhosis, the mortality due to hemorrhage is higher than in chronic PVT. Therefore, for the patients with PVT, the survival rate is decreased by 55% in two years, due to hepatic insufficiency. Regarding the treatment, LMWH (low molecular weight heparine) is the most utilized in patients with cirrhosis, non-malignancies, infections, or those who are awaiting a liver transplant. DOACs (direct-acting oral anticoagulants) may be used in the rest of the medical conditions, being safe and equal to LMWH.

Comparison of Traumatic Intracranial Hemorrhage Expansion and Outcomes Among Patients on Direct Oral Anticoagulants Versus Vitamin k Antagonists

BACKGROUND

With increasing use of direct oral anticoagulants (DOACs) and availability of new reversal agents, the risk of traumatic intracranial hemorrhage (tICH) requires better understanding. We compared hemorrhage expansion rates, mortality, and morbidity following tICH in patients treated with vitamin k antagonists (VKA: warfarin) and DOACs (apixaban, rivaroxaban, dabigatran).

METHODS

Retrospective chart review of patients from 2010 to 2017 was performed to identify patients with imaging diagnosis of acute traumatic intraparenchymal, subdural, subarachnoid, and epidural hemorrhage with preadmission use of DOACs or VKAs. We identified 39 patients on DOACs and 97 patients on VKAs. Demographic information, comorbidities, hemorrhage size, and expansion over time, as well as discharge disposition and Glasgow Outcome Scale (GOS) were collected. Primary outcome was development of new or enlargement of tICH within the first 48 h of initial CT imaging.

RESULTS

Of 136 patients with mean (SD) age 78.7 (13.2) years, most common tICH subtype was subdural hematoma (N = 102/136; 75%), and most common mechanism was a fall (N = 130/136; 95.6%). Majority of patients in the DOAC group did not receive reversal agents (66.7%). Hemorrhage expansion or new hemorrhage occurred in 11.1% in DOAC group vs. 14.6% in VKA group (p = 0.77) at a median of 8 and 11 h from initial ED admission, respectively (p = 0.82). Patients in the DOAC group compared to VKA group had higher median discharge GOS (4 vs. 3 respectively, p = 0.03), higher percentage of patients with good outcome (GOS 4-5, 66.7% vs. 40.2% respectively, p = 0.005), and higher rate of discharge to home or rehabilitation (p = 0.04).

CONCLUSIONS

We report anticoagulation-associated tICH outcomes predominantly due to fall-related subdural hematomas. Patients on DOACs had lower tICH expansion rates although not statistically significantly different from VKA-treated patients. DOAC-treated patients had favorable outcomes versus VKA group following tICH despite low use of reversal strategies. DOAC use may be a safer alternative to VKA in patients at risk of traumatic brain hemorrhage.

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

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

Retrospective Review on the Safety and Efficacy of Direct Oral Anticoagulants Compared With Warfarin in Patients With Cirrhosis

Purpose

Patients with cirrhosis needing anticoagulation therapy have historically been prescribed warfarin. New retrospective research has concluded that in patients with cirrhosis direct oral anticoagulants (DOACs) have similar or lower bleeding rates compared with that of warfarin. This study compares the safety and efficacy of DOACs with that of warfarin in patients with cirrhosis.

Methods

A retrospective chart review was conducted in adult patients with cirrhosis taking either apixaban, dabigatran, edoxaban, rivaroxaban, or warfarin. Exclusion criteria consisted of patients prescribed triple antithrombotic therapy (dual antiplatelet therapy plus an anticoagulant) and indications other than nonvalvular atrial fibrillation (NVAF) and venous thromboembolism (VTE). The primary endpoint was all-cause bleeding, and the secondary endpoints were failed efficacy and major bleeding as defined by the International Society on Thrombosis and Haemostasis in 2005. Failed efficacy was a combination endpoint including the development of VTE, stroke, myocardial infarction and/or death. Patient data were collected from the Computerized Patient Record System from October 31, 2014 to October 31, 2018.

Results

The study included 42 patients in the DOAC group and 37 patients in the warfarin group. Baseline characteristics were not significantly different between groups except for the Child-Turcotte-Pugh score, Model for End-Stage Liver Disease score, international normalized ratio, and number of days on anticoagulation therapy. The rate of all-cause bleeding in the DOAC group was 16.7% (n = 7) vs 21.6% (n = 8) in the warfarin group (P = .7). The rate of major bleeding in the DOAC group was 2.4% (n = 1) vs 5.4% (n = 2) in the warfarin group (P = .6). The rate of failed efficacy in the DOAC group was 7.1% (n = 3) compared with 8.1% (n = 3) in the warfarin group (P = .9). Subgroup analysis of allcause bleeding did not identify any significant trends between groups.

Conclusions

There were no statistically significant differences identified between the rates of all-cause bleeding, major bleeding, and failed efficacy between the DOACs and warfarin groups. DOACs may be a safe alternative to warfarin in patients with cirrhosis requiring anticoagulation for NVAF or VTE, but large randomized trials are required to confirm these results.

Chronic Kidney Disease and Its Impact on a Prothrombotic State in Patients with Atrial Fibrillation

It is unclear whether chronic kidney disease (CKD) increases thromboembolism in atrial fibrillation (AF). We conducted a retrospective cross-sectional analysis of 502 non-anticoagulated AF patients (median age, 66 (60–73) years, median CHA₂DS₂-VASc score, 3.0 (2.0–4.0)) with an estimated glomerular filtration rate (eGFR) ≥ 15 mL/min/1.73 m². Endogenous thrombin potential (ETP), clot permeability (K_s), and clot lysis time (CLT), among others, were determined. Patients with stage 4 CKD (n = 87; 17.3%) had higher ETP and prolonged CLT compared with those with stage 3 CKD. In patients with stages 3 to 4 CKD (n = 180; 35.9%) N-terminal pro-B-type natriuretic peptide predicted low K_s (the lowest quartile, odds ratio [OR] per 100 pg/mL: 1.03, 95% confidence interval [CI]: 1.01–1.06) and prolonged CLT (the top quartile, OR per 100 pg/mL: 1.05, 95% CI: 1.02–1.08), but not high ETP. In the whole cohort, after adjustment for CHA₂DS₂-VASc score, stage 4 CKD, but not stage 3 CKD, predicted high ETP (OR: 9.06; 95% CI: 4.44−18.46) and prolonged CLT (OR: 3.58; 95% CI: 1.76–7.28), but not low K_s. compared to the reference eGFR category. This study is the first to demonstrate the prothrombotic and antifibrinolytic alterations in AF patients with stage 4 CKD, but not stage 3 CKD irrespective of clinical stroke risk factors.

Therapeutic strategies for thrombosis: new targets and approaches

Antiplatelet agents and anticoagulants are a mainstay for the prevention and treatment of thrombosis. However, despite advances in antithrombotic therapy, a fundamental challenge is the side effect of bleeding. Improved understanding of the mechanisms of haemostasis and thrombosis has revealed new targets for attenuating thrombosis with the potential for less bleeding, including glycoprotein VI on platelets and factor XIa of the coagulation system. The efficacy and safety of new agents are currently being evaluated in phase III trials. This Review provides an overview of haemostasis and thrombosis, details the current landscape of antithrombotic agents, addresses challenges with preventing thromboembolic events in patients at high risk and describes the emerging therapeutic strategies that may break the inexorable link between antithrombotic therapy and bleeding risk.

Oral Anticoagulant Therapy-When Art Meets Science

Anticoagulant treatment is extremely important and frequently encountered in the therapy of various cardiovascular diseases. Vitamin K antagonists (VKA) are in use for the prevention and treatment of arterial and venous thromboembolism, despite the introduction of new direct-acting oral anticoagulants (NOAC). The VKA still have the clear recommendation in patients with a mechanical prosthetic heart valve replacement or moderate to severe mitral stenosis of the rheumatic origin, in deep vein thrombosis associated with congenital thrombophilia, and in cases where NOAC are prohibited by social condition (financial reason) or by comorbidities (extreme weight, severe renal or liver disease). VKA dosing required to reach the targeted therapeutic range varies largely between patients (inter-individual variability). This inter-individual variability depends on multiple environmental factors such as age, mass, diet, etc. but it is also influenced by genetic determinism. About 30 genes implicated in the metabolism coumarins derivatives were identified, the most important being CYP2C9 and VKORC, each with several polymorphisms. Herein, we review the data regarding genetic alterations in general and specific populations, highlight the diagnosis options in particular cases presenting with genetic alteration causing higher sensitivity and/or resistance to VKA therapy and underline the utility of NOAC in solving such rare and difficult problems.

Non-medical prescribing: a reflective case study on prescribing anticoagulation for deep vein thrombosis

Prescribing is a high-risk, complex skill. There are more than 50,000 nurse prescribers in the UK, and it is important that they undertake regular reflection on their clinical practice to enhance their skills. This article reflects on the clinical factors that influenced the author's decision-making when prescribing anticoagulation medication for a patient with deep vein thrombosis. It also explores the evidence base for commonly prescribed anticoagulants.

Update on Management of Portal Vein Thrombosis and the Role of Novel Anticoagulants

The clinical management of portal vein thrombosis (PVT) remains ambiguous due to its heterogeneous presentations and its associations with liver disease, malignancy, and hypercoagulable states. The natural history and clinical outcome of PVT are highly variable, dependent upon size, extent and degree of the thrombotic occlusion, as well as the physiological impact of patient comorbidities. While existing clinical guidelines consistently recommend low molecular weight heparin or vitamin K antagonist anticoagulation in cirrhotic patients with symptomatic acute PVT, management of asymptomatic and chronic PVT may need to be determined on a case-by-case basis, factoring in the state of underlying liver disease. In general, patients with PVT and underlying malignancy should be anticoagulated to alleviate symptoms and prevent recurrences that could disrupt the cancer management. However, existing clinical data does not support routine anticoagulation of cirrhotic patients with asymptomatic PVT in the absence of underlying cancer. While low molecular weight heparin and vitamin K antagonist remain the most commonly used agents in PVT, an emerging body of clinical evidence now suggests that direct-acting oral anticoagulants may be used safely and effectively in PVT. As such, direct-acting oral anticoagulants may offer a more convenient anticoagulation alternative for PVT management in future practice.

The acceptability of a direct oral anticoagulant monitoring regimen among patients with atrial fibrillation: a pilot study

Background The direct oral anticoagulants (DOACs) offer several advantages over warfarin in the management atrial fibrillation, including the provision of fixed dosing without a requirement for regular monitoring. Recently however the subject of DOAC monitoring has been probed after several post-hoc analyses demonstrated an association between plasma levels and efficacy and safety events. Objective The aim of this pilot study was to explore the acceptability of DOAC plasma monitoring amongst patients with atrial fibrillation and the factors that may influence these attitudes. Method A simple DOAC monitoring schedule based on the dabigatran pharmacokinetic profile was developed. A cross-sectional survey was distributed to patients with atrial fibrillation asking them to indicate their likelihood of taking a particular DOAC subjected to plasma monitoring. Results Thirty patients participated in the study. Most patients (63.3%) favoured taking a DOAC subjected to monitoring under the proposed schedule, citing increased efficacy and reduced toxicity as the reasons for their response. Conclusion There is some suggestion that atrial fibrillation patients may in fact favour taking a DOAC subjected to infrequent monitoring if this enhanced safety and efficacy.

Rapidly Neutralizable and Highly Anticoagulant Thrombin-Binding DNA Aptamer Discovered by MACE SELEX

We present a rapidly neutralizable and highly anticoagulant thrombin-binding aptamer with a short toehold sequence, originally discovered by systematic evolution of ligands by exponential enrichment (SELEX) with microbead-assisted capillary electrophoresis (MACE). MACE is a novel CE-partitioning method for SELEX and able to separate aptamers from a library of unbound nucleic acids, where the aptamer and target complexes can be detected reliably and partitioned with high purity even in the first selection cycle. Three selection rounds of MACE-SELEX discovered several TBAs with a nanomolar affinity (K_d = 4.5-8.2 nM) that surpasses previously reported TBAs such as HD1, HD22, and NU172 (K_d = 118, 13, and 12 nM, respectively). One of the obtained aptamers, M08, showed a 10- to 20-fold longer prolonged clotting time than other anticoagulant TBAs, such as HD1, NU172, RE31, and RA36. Analyses of the aptamer and thrombin complexes using both bare and coated capillaries suggested that a large number of efficient aptamers are missed in conventional CE-SELEX because of increased interaction between the complex and the capillary. In addition, the toehold-mediated rapid antidote was designed for safe administration. The efficient aptamer and antidote system developed in the present study could serve as a new candidate for anticoagulant therapy.

The New/Novel Oral Anticoagulants and Their Impact on Patients Being Considered for Shockwave Lithotripsy: The Findings of an International Survey of the Endourological Society

INTRODUCTION

Although general guidelines exist directing the management of new/novel oral anticoagulants (NOACs) in the perioperative period for open/endoscopic procedures, no consensus exists for those patients being considered for shockwave lithotripsy (SWL). To gauge current practice, we administered a survey to the international endourologic community.

METHODS

A web-based survey was sent to current Endourological Society members. Respondents were asked whether they would consider SWL in patients receiving NOACs, and if they used SWL how these agents were managed perioperatively. Respondents were also asked which physicians in the patients' circle of care managed the discontinuation and reinstitution of the drugs.

RESULTS

There were 165 respondents from 27 countries. Approximately 92.7% of urologists had access to SWL but only 53.4% indicated they would offer SWL to patients receiving NOACs. Among these urologists, 63.3% relied on internal medicine/hematology/cardiology colleagues to counsel patients on the discontinuation of NOACs pretreatment, whereas the majority (64%) handled the resumption guidance themselves. There was wide variability in the management of NOACs before lithotripsy, with discontinuation varying from 2 to 7 days. Resumption was more consistent, ranging from 1 to 2 days or when hematuria resolved. None of the respondents reported knowledge of adverse effects such as perinephric hematomas or cardiovascular morbidity.

CONCLUSIONS

A large percentage of globally surveyed endourologists do not offer SWL to patients who are taking NOACs. Among those that do offer SWL, there seems to be a absence of consensus on optimal duration of discontinuation, suggesting a need to establish evidence-based guidance to optimize patient outcomes.