Coagulation assessment with the new generation of oral anticoagulants

Direct-Acting Oral Anticoagulant/Vitamin K Antagonists: Do They Affect the Trabecular and Cortical Structure of the Mandible?

BACKGROUND

This study aimed to evaluate the mandibular bone structure of patients using oral anticoagulants (OACs) vitamin K antagonist drugs (warfarin) and other OACs including direct oral anticoagulants [(DOACs) apixaban, rivaroxaban, dabigatran, edoxaban]. Analyses were based upon the fractal dimension (FD), the panoramic mandibular index (PMI) and the Klemetti index (KI), which is also known as the mandibular cortical index (MCI).

METHODOLOGY

Ninety participants were divided into three groups: group 1: 30 systemically healthy individuals who had not used any anticoagulants before, group 2: 30 individuals using warfarin, and group 3: 30 individuals using DOACs. FD was used to analyze trabecular bone architecture in the condyle, angle, and two sites in the alveolar bone. PMI was used to evaluate the quantity of cortical bone and KI was used to evaluate the cortical bone quality.

RESULTS

There was no difference between the groups regarding FD analysis and KI; however, a difference was found between groups 1, 2, and 3 in the PMI (P≤ 0.001). The PMI in group 1 was higher than in groups 2 and 3.

CONCLUSION

Mandibular radiomorphometric indices can be used on panoramic radiographs to evaluate the quantity of mandibular cortical bone in patients using oral anticoagulants.

Calibration-free electrochemical sensor to monitor factor-Xa inhibitors at the point-of-care anticoagulation therapy

This article presents a novel proof of concept for the blood plasma quantification of clinically relevant concentrations of direct oral anticoagulants, DOACs, including rivaroxaban and edoxaban, as well as low-molecular-weight heparins, LMWHs, such as enoxaparin and dalteparin, utilising a calibration-free disposable electrochemical sensor with co-facing electrodes. A dose-response curve was generated for rivaroxaban and edoxaban to demonstrate the sensor's ability to detect ≥9.00 ng mL-1 rivaroxaban and quantify it in the 11.0-140 ng mL-1 range. Similarly, the lower detection limit for edoxaban was 12.9 ng mL-1, with a quantification range of 16.8-140 ng mL-1. The significance of this sensor lies in its ability to quantify rivaroxaban and edoxaban below 30 ng mL-1, which is crucial in emergency care centres when patients undergoing DOAC therapy require emergency surgery or reversal of DOACs due to bleeding or ischemic stroke. Furthermore, the sensor can detect ≥0.016 IU mL-1 enoxaparin and ≥0.013 IU mL-1 dalteparin and quantify them in the 0.025-0.75 and 0.019-0.75 IU mL-1 range, respectively. Additionally, a dose-response curve was presented to demonstrate the potential ability of this sensor to quantify factor-Xa inhibitors independently of which DOACs or LMWHs are used. With the assay completed in less than 30 s using a minimal volume of 7 μL sample, the possibility to work at physiological pH and under calibration-free format makes this assay an excellent candidate for point-of-care testing.

Apixaban-Associated Intracranial Hemorrhage in a Patient With Elevated International Normalized Ratio

Apixaban has been associated with prolongation of the international normalized ratio (INR), but data surrounding the extent of elevation and its clinical significance are limited. Due to interaction between apixaban and the prothrombin assay, elevations in INR in patients receiving apixaban are common and not always grounds for concern. However, in high risk patients, elevations can represent a need for closer monitoring. This case summarizes an 82-year-old woman with a history of atrial fibrillation and left middle cerebral artery strokes with no residual deficits. She presented with right-sided hemiparesis and aphasia and underwent a mechanical thrombectomy with TICI 2b recanalization of a left M1 occlusion. Post-thrombectomy, she was found to have a left atrial thrombus and 10 days later was started on apixaban 5 mg twice daily. On the fourth day of apixaban therapy, she experienced an INR increase to 2.3, prompting initiation of a vitamin K challenge for nutritional deficiency. Despite initial improvement, her INR increased to 2.7 a week after apixaban was initiated, coinciding with a decline in mental status and an apixaban peak level of 435.6 ng/mL (reference range 91-321 ng/mL). A computed tomography (CT) scan of her head showed new intracranial hemorrhage in the area of her previous infarction, prompting apixaban reversal with andexanet alfa. Unfortunately, the patient expired. This case report highlights the importance and difficulty in performing therapeutic drug monitoring in patients receiving oral anti-factor Xa inhibitors, revealing a downside to administration of high-risk medications that do not have readily available monitoring.

Being precise with anticoagulation to reduce adverse drug reactions: are we there yet?

Anticoagulants are potent therapeutics widely used in medical and surgical settings, and the amount spent on anticoagulation is rising. Although warfarin remains a widely prescribed oral anticoagulant, prescriptions of direct oral anticoagulants (DOACs) have increased rapidly. Heparin-based parenteral anticoagulants include both unfractionated and low molecular weight heparins (LMWHs). In clinical practice, anticoagulants are generally well tolerated, although interindividual variability in response is apparent. This variability in anticoagulant response can lead to serious incident thrombosis, haemorrhage and off-target adverse reactions such as heparin-induced thrombocytopaenia (HIT). This review seeks to highlight the genetic, environmental and clinical factors associated with variability in anticoagulant response, and review the current evidence base for tailoring the drug, dose, and/or monitoring decisions to identified patient subgroups to improve anticoagulant safety. Areas that would benefit from further research are also identified. Validated variants in VKORC1, CYP2C9 and CYP4F2 constitute biomarkers for differential warfarin response and genotype-informed warfarin dosing has been shown to reduce adverse clinical events. Polymorphisms in CES1 appear relevant to dabigatran exposure but the genetic studies focusing on clinical outcomes such as bleeding are sparse. The influence of body weight on LMWH response merits further attention, as does the relationship between anti-Xa levels and clinical outcomes. Ultimately, safe and effective anticoagulation requires both a deeper parsing of factors contributing to variable response, and further prospective studies to determine optimal therapeutic strategies in identified higher risk subgroups.

Antithrombotic Usage, Including Three-Year Outcomes With Dabigatran and Vitamin K Antagonists for Atrial Fibrillation, in Eastern Europe: A Descriptive Analysis From Phase 3 of the GLORIA-AF Registry

BACKGROUND

Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF) is a prospective registry of outcomes from patients with newly diagnosed AF at risk of stroke. In the propensity score (PS)-matched global population of phase 3 GLORIA-AF, at 3 years, dabigatran-treated patients experienced reduced risk for major bleeding, and similar risk for stroke and myocardial infarction, compared with vitamin K antagonist (VKA)-treated patients.

STUDY QUESTION

Do patients in Eastern Europe benefit from treatment with dabigatran versus VKA?

STUDY DESIGN

Descriptive analysis, without PS matching. To contextualize the Eastern Europe results of GLORIA-AF phase 3, we also descriptively analyzed the global population without PS matching. Consecutive patients with newly diagnosed AF and CHA2DS2-VASc-score ≥1 were enrolled until December 2016 in 38 countries (9 in Eastern Europe).

MEASURES AND OUTCOMES

Three-year outcomes with dabigatran and VKA.

RESULTS

In Eastern Europe, 1341 patients were eligible (6% of patients globally), and incidence rates (per 100 patient-years) for the following outcomes were numerically lower with dabigatran (N = 498) versus VKA (N = 466): major bleeding (0.26 vs. 0.90), all-cause death (2.04 vs. 3.50), and a composite of stroke, systemic embolism, myocardial infarction, life-threatening bleeding, and vascular death (1.37 vs. 1.92); stroke was comparable (0.51 vs. 0.50). All incidence rates were numerically lower in Eastern Europe versus the global population for both treatments. Chronic concomitant use of high bleeding risk medications (eg, nonsteroidal anti-inflammatories) was lower in Eastern Europe (dabigatran 3.8%, VKA 9.3%) than globally (dabigatran 14.8%, VKA 20.6%) and persistence with dabigatran was higher in Eastern Europe (76%) than globally (64%).

CONCLUSIONS

Dabigatran was associated with numerically reduced major bleeding, all-cause death, and cardiovascular (CV) composite, with comparable risk of stroke versus VKA, in Eastern Europe. Limitations of this descriptive analysis include few CV events (n = 11 for stroke, in the dabigatran and VKA groups combined) and a lack of statistical analysis and PS matching, which precludes definitive conclusions; however, the CV outcomes in Eastern Europe were consistent with the beneficial impact of dabigatran versus VKA in the statistically analyzed global population with PS matching.

Bleeding risk in female patients undergoing intravesical injection of onabotulinumtoxinA for overactive bladder: a Danish retrospective cohort study

INTRODUCTION AND HYPOTHESIS

We aimed to examine the risk of bleeding in female patients undergoing intravesical onabotulinumtoxinA (BTX-A) treatments and provide clinical recommendations for the perioperative management of patients on antithrombotic therapy prior to BTX-A treatments.

METHODS

This was a retrospective cohort of Danish female patients, who had their first BTX-A treatment because of an overactive bladder at the Department of Gynecology and Obstetrics, Herlev and Gentofte University Hospital, between January 2015 and December 2020. Data extraction was from an electronic medical journal system. BTX-A, Botox® Allergan was injected in the detrusor at 10-20 sites. Significant bleeding during or after a BTX-A treatment was defined as persistent macroscopic hematuria. Bleeding reporting was based on information obtained from journal notes.

RESULTS

We included 400 female patients, who had a total of 1,059 BTX-A treatments. Median age at first BTX-A treatment was 70 years (IQR 21), and median number of BTX-A treatments was 2 (range 1-11). In total, 27.8% (n=111) received antithrombotic therapy. Within this group, 30.6% and 69.4% were on anticoagulant and antiplatelet therapy. No cases of hematuria were reported in our cohort. We found that no patients stopped their antithrombotic therapy, were bridged, or monitored by International Normalized Ration (INR) levels.

CONCLUSIONS

We suggest that BTX-A treatments might be classified as low-risk procedures. Discontinuation of antithrombotic therapy is not required in the perioperative management of this patient group.

Electrochemical Disposable Biosensor to Monitor Dabigatran in Point-of-Care Anticoagulation Therapy

Dabigatran etexilate, an oral prodrug, is often used to treat complications linked to thrombosis. Dabigatran (DAB, active form) does not need to be monitored. However, there are several conditions, such as reduced renal function, traumatic bleeding, emergency surgery, the need for thrombolytic therapy in acute stroke, or the requirement to use other forms of anticoagulation, where knowing the concentration of DAB in the blood is indispensable. Unfortunately, there are no convenient DAB-specific point-of-care tests available. To solve this problem, two disposable sensors were constructed and optimised in this work to detect the anticoagulant drug DAB using novel co-facing disposable electrodes, which allows a calibration-free quantitation of the electroactive mediator concentration. A trypsin-based sensor was evaluated. This sensor performed well in a 10 mM Tris buffer (pH 8.8) solution. However, trypsin was inhibited by alpha-1 antitrypsin when a plasma sample was introduced into the sensor. This problem was overcome by plasma filtration. This sensor showed a detection limit of 50.7 ng mL^-1 DAB in plasma and a quantification range of 177-500 ng mL^-1. A thrombin-based sensor was also constructed. This sensor performed well in ten-fold diluted plasma, overcoming the filtration problem observed with the trypsin-based sensor. This sensor showed a detection limit of 9.6 ng mL^-1 DAB in plasma and a quantification range of 11.5-140 ng mL^-1. Its extensive pH stability range, the possibility of working at physiological pH, low volume, low cost, and fast turnaround response (less than 20 s) make the calibration-free thrombin-based sensor a suitable point-of-care test to measure DAB concentration in the blood.

Bleeding on oral anticoagulants: overview of reversal strategies

Oral anticoagulants (antivitamin K, direct oral anticoagulants) are routinely prescribed for the prevention or treatment of thromboembolic events, and many patients are now on long-term anticoagulant therapy. However, this complicates the management of urgent surgical conditions or major bleeding. Various strategies have been developed to reverse the anticoagulant effect and this narrative review provides an overview of the wide range of therapies currently available.

Dry Needling and Antithrombotic Drugs

Many clinicians increasingly use dry needling in clinical practice. However, whether patients' intake of antithrombotic drugs should be considered as a contraindication for dry needling has not been investigated to date. As far as we know, there are no publications in analyzing the intake of antiplatelet or anticoagulant agents in the context of dry needling techniques. A thorough analysis of existing medications and how they may impact various needling approaches may contribute to improved evidence-informed clinical practice. The primary purpose of this paper is to review the current knowledge of antithrombotic therapy in the context of dry needling. In addition, reviewing guidelines of other needling approaches, such as electromyography, acupuncture, botulinum toxin infiltration, and neck ultrasound-guided fine-needle aspiration biopsy, may provide specific insights relevant for dry needling. Based on published data, taking antithrombotic medication should not be considered an absolute contraindication for dry needling techniques. As long as specific dry needling and individual risks are properly considered, it does not change the risk and safety profile of dry needling. Under specific circumstances, the use of ultrasound guidance is recommended when available.

How to level the risk of bleeding while taking anticoagulant therapy in patients with atrial fibrillation?

Atrial fibrillation (AF) is one of the most common types of cardiac arrhythmias, while AF is the main risk factor for ischemic stroke. For a long time, vitamin K antagonists, primarily warfarin, have been the standard for the prevention of thromboembolic complications in patients with AF. 5 years ago, dabigatran, rivaroxaban and apixaban occupied the 2nd place in the structure of anticoagulant prescribing (AC), giving way to warfarin. The well-known reason for the inadequate use of AC is the risk of bleeding. There are a large number of validated scales for assessing the risk of hemorrhagic complications, in particular HAS-BLED, ABC, HEMORRHR2HAGES, ATRIA, ORBIT, but the estimated high risk of bleeding should not be the only and absolute limitation to the appointment of AC. Despite the real risk of bleeding on the background of taking AC in patients with AF, an integrated approach taking into account not only the risk factors of the thromboembolic complications, but also hemorrhagic complications, with an emphasis on the existing comorbidities, the presence of comorbidity, old age, etc., will allow an individual approach to the choice of AC and its dose, contributing to the optimization of the management of such kind of patients.

Feasibility of the MELD score as a screening tool for pharmacists to identify patients with impaired hepatic function at hospital admission

WHAT IS KNOWN AND OBJECTIVE

Hepatic impairment (HI) is a known risk factor for drug safety. The MELD score (Model-for-endstage-liver-disease), calculated from serum creatinine, bilirubin and International Normalized Ratio (INR), is a promising screening tool corresponding to Child-Pugh Score (CPS) for drug adjustment. We tested the feasibility of MELD as an automatic screening tool accounting for correct calculation, interfering factors (IF) and detection of patients corresponding to CPS-B/C potentially requiring drug adjustment.

METHODS

We retrospectively calculated MELD for a 3-month cohort of surgical patients and assessed need for adjustment of MELD parameters to standard values. IF for INR (oral anticoagulants) and serum creatinine (renal insufficiency (RI; eGFR<60 ml/min/1.73m²); as well as drugs elevating creatinine levels (DECL)) and the number of patients with MELD scores corresponding to CPS-B/C were analysed. For MELD ≥7.5, liver and bile diagnoses were recorded.

RESULTS AND DISCUSSION

Of 1183 patients, MELD was calculable for 761 (64%; median 7.5, range 6.4-36.8). Parameters had to be adjusted for 690 (91%) patients. IF of parameters were RI in 172 (23%), INR-elevating drugs in 105 (14%) and DECL in 33 (4%) patients. Of 335 (44%) patients with MELD ≥7.5, 122 (36%) had documented liver or bile diagnoses. MELD 10-<15 (corresponding to CPS-B) was found for 105 (14%), MELD ≥15 (corresponding to CPS-C) for 66 (9%) of the 761 patients with a calculated MELD. Referred to all patients, drug adjustments due to possible HI were recommendable for 14% of patients with suspected CPS-B/C.

WHAT IS NEW AND CONCLUSION

MELD is a feasible screening tool for HI as a risk factor for drug safety at hospital admission when appropriately considering correct parameter adjustment and RI and INR-elevating drugs as IF. Further evaluation of sensitivity and specificity is needed.

Highly sensitive and selective lateral flow aptasensor for anti-coagulant dabigatran etexilate determination in blood

Dabigatran etexilate (DBG) is a new anticoagulant drug (commercially sold under the names Pradaxa® and Pradax™) that replaces Warfarin, the landmark agent for anticoagulation therapy. Inadequate administration of DBG or in the cases of massive bleeding that occurs after renal impairment, DBG therapy can carry a substantial life-threatening risks. One of the major limitations of DBG treatment is the lack of a simple and quick tool for measuring its level in blood in the case of massive bleedings or emergency operations. In this work, we have incorporated a previously isolated aptamer for DBG to develop a simple competitive lateral flow aptasensor (LFA) for the determination of DBG in buffer and blood samples. A full-length 60-mer aptamer as well as a truncated 38-mer aptamer were conjugated to gold nanoparticles (AuNPs) via thiol-Au coupling chemistry. After appropriate AuNP surface passivation steps, the aptamer's core region was hybridized with 8-mer biotinylated sequences. The conjugated particles could be capture on the test line by the interaction of the biotin molecules with a previously deposited streptavidin. Incubation of the conjugated particles with DBG causes the aptamer to undergo a conformational change that releases the 8-mer biotinylated sequences and result in the disappearance of the test line. Lysozyme protein was used to construct the control line that non-specifically interacts with the conjugated particles whether or not the target compound is present. The developed LFA achieves 20 nM detection level in buffer and blood samples, operates within the nanomolar range, and shows excellent selectivity against potential interfering molecules. The developed sensor could help assessing the levels of DBG in medical conditions that require rapid interventions.

Drop-of-blood acoustic tweezing technique for integrative turbidimetric and elastometric measurement of blood coagulation

Many patients develop coagulation abnormalities due to chronic and hereditary disorders, infectious disease, blood loss, extracorporeal circulation, and oral anticoagulant misuse. These abnormalities lead to bleeding or thrombotic complications, the risk of which is assessed by coagulation analysis. Current coagulation tests pose safety concerns for neonates and small children due to large sample volume requirement and may be unreliable for patients with coagulopathy. This study introduces a containerless drop-of-blood method for coagulation analysis, termed "integrated quasi-static acoustic tweezing thromboelastometry" (i-QATT™), that addresses these needs. In i-QATT™, a single drop of blood is forced to levitate and deform by the acoustic radiation force. Coagulation-induced changes in drop turbidity and firmness are measured simultaneously at different instants. The parameters describing early, intermediate, and late stages of the coagulation process are evaluated from the resulting graphical outputs. i-QATT™ rapidly (<10 min) detected hyper- and hypo-coagulable states and identified single deficiency in coagulation factors VII, VIII, IX, X, and XIII. The linear relationship (r² > 0.9) was established between fibrinogen concentration and two i-QATT™ parameters: maximum clot firmness and maximum fibrin level. Factor XIII activity was uniquely measured by the fibrin network formation time (r² = 0.9). Reaction time, fibrin formation rate, and time to firm clot formation were linearly correlated with heparin concentration (r² > 0.7). tPA-induced hyperfibrinolysis was detected in the clot firmness output at 10 min. i-QATT™ provides comprehensive coagulation analysis in point-of-care or laboratory settings, well suited to the needs of neonatal and pediatric patients and adult patients with anemia or blood collection issues.

Efficacy and Safety of Perioperative Bridging Anticoagulation in Patients with Atrial Fibrillation Undergoing Elective Surgical Procedures: A Meta-analysis

Objective: The study objective was to determine if peri-operative bridging anticoagulation in patients with atrial fibrillation is beneficial or harmful.Design: Systematic review and meta-analysis.Setting: Inpatient or in-hospital setting.Participants: Adults with atrial fibrillation having a CHADS2 score >1 undergoing elective surgical procedure on anticoagulation.Methods: A systemic search of multiple databases (Cochrane, Medline, PubMed) was performed regarding studies conducted on efficacy and safety of perioperative bridging anticoagulation in patients with atrial fibrillation. Studies identified were reviewed by two authors individually before inclusion. The results were then pooled using Review Manager to determine the combined effect. Stroke/systemic embolism was considered as the primary efficacy outcome. Major bleeding was the primary safety outcome.Results: The systematic search revealed 108 potential articles. The full texts of 28 articles were retrieved for assessment of eligibility. After full text review, 25 articles were excluded. Three articles met inclusion criteria. No significant difference in stroke/systemic embolism with bridging anticoagulation was noted (risk ratio, 1.25-95% confidence interval [CI], 0.55-2.85). Bridging was associated with significantly higher risk of major bleeding (risk ratio, 3.29-95% CI, 2.25-4.81).Conclusion: An individualized approach is required when initiating peri-operative bridging anticoagulation. There is certainly a higher risk of bleeding with bridging anticoagulation and no difference in stroke/systemic embolism. However, the results cannot be extrapolated to patients who have valvular atrial fibrillation or CHADS2 score of 5 or greater.

Pitfalls in the assessment of disseminated intravascular coagulation in patients on dabigatran

Dabigatran is an orally administrated anticoagulant that directly inhibits thrombin. However, the drug can affect routine coagulation tests such as prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT), as well as haemostasis assays, (e.g., clot-based coagulation factor assays). There are limited data on the effect of dabigatran on some fibrinogen measurements and on D-dimer assays, both important components in the laboratory assessment of disseminated intravascular coagulation (DIC). The objectives of this study were: (1) to determine the effects of various concentrations of dabigatran on fibrinogen and D-Dimer assays; and (2) to compare the von Clauss method of fibrinogen measurement using two reagents with differing thrombin concentrations (35 UNIH/mL and 100 UNIH/mL) and PT-derived fibrinogen measurement in the presence of the drug. Aliquots of pooled normal plasma were spiked with different concentrations of dabigatran to reflect in vivo on-therapy levels as well as levels observed in cases of massive accumulation of the drug. Of the routine coagulation assays, in ascending order of sensitivity to dabigatran were PT, APTT and TT. The von Clauss method of measuring fibrinogen using a reagent with low thrombin concentration was affected even at drug levels corresponding to in vivo trough concentrations, whereas the reagent with higher thrombin concentration was only affected at drug levels that were above observed peak concentrations in patients taking 150 mg of the drug twice daily. PT-derived fibrinogen was affected at approximately in vivo peak drug concentrations. The D-dimer assay was affected only at drug concentrations well above peak drug levels. Attempts at in vitro neutralisation of the drug with DOAC-Stop resulted in 'correction' of some of these measurements depending on drug concentration. Like the routine coagulation assays, there is a dabigatran concentration dependent effect on the accuracy of fibrinogen and D-dimer assays. Falsely low fibrinogen results due to dabigatran may confound the assessment of DIC and diagnostic laboratories need to evaluate the performance of their own reagents.

Virtual Patient Simulation in Continuing Education: Improving the Use of Guideline-Directed Care in Venous Thromboembolism Treatment

Results of a CME-certified activity completed by a total of 986 cardiologists and 783 haematologists-oncologists (haem-oncs) from around the world were examined to determine whether virtual patient simulation could improve decision-making and performance within the simulation related to patient evaluation, tailoring anticoagulant therapy, and patient management to improve adherence using patient-centred care strategies. Results showed a significant overall impact of education from pre- to post-clinical guidance (CG) on correct decisions made in both cases for cardiologists, with a relative improvement of 22% for Case 1 (45% pre- to 55% post-CG, n = 475, t(474) = 14.12, P<.001, Cohen’s d =.46) and 19% for Case 2 (62% pre- to 74% post-CG, n = 245, t(244) = 11.95, P<.001, Cohen’s d =.59). Impact also was seen for haem-oncs, with a relative improvement of 27% for Case 1 (45% pre- to 57% post-CG, n = 280, t(279) = 11.91, P <.001, Cohen’s d =.60) and 19% for Case 2 (63% pre- to 75% post-CG, n = 147, t(146) = 9.52, P <.001, Cohen’s d =.58). Virtual patient simulation improved cardiologists’ and haem-oncs management of patients with pulmonary embolism in a simulated environment.

Direct-acting oral anti-coagulants in dental practice: A Retrospective Observational Study (Part 1)

OBJECTIVES

The objective of this retrospective observational study was to determine the incidence of direct-acting oral anti-coagulant (DOA) use in patients receiving invasive dental procedures. The secondary objective was to investigate the precautionary measures implemented and the post/intraoperative complications associated with DOA use.

METHODS

Electronic record database, Axium, was retrospectively reviewed, and patients using NGOA and treated between 2010 and 2017 were identified. Charts of patients who underwent invasive dental procedures were further reviewed to investigate the preoperative/intraoperative precautionary measures taken and identify any intraoperative/postoperative complications.

RESULTS

A total of 130 patients were identified, with their annual number steadily rising from 12 in 2011 to 52 in 2016. Among those, 64 patients (49.23%) underwent invasive dental procedures. Pretreatment medical consults were obtained in all patients undergoing invasive procedures; however, only 7 (10.94%) were instructed to discontinue their DOA. Preoperative laboratory testing was obtained for two patients. Intraoperatively, 34 (53.13%) cases of excessive bleeding were reported, all were locally controlled with hemostatic agents. Only 4 instances of postoperative complications were documented.

CONCLUSIONS

Despite the rise in the use of DOA, there is no consistent pattern for preoperative laboratory testing and DOA discontinuations. Expert consensus may be of great importance to develop practice guidelines.

Peri-procedural novel oral anticoagulants dosing strategy during atrial fibrillation ablation: A meta-analysis

BACKGROUND

This study aimed at determining whether uninterrupted novel oral anticoagulant (UI-NOAC) would have similar rates of bleeding and thromboembolic events as minimally interrupted NOAC (MI-NOAC) at the time of ablation for atrial fibrillation (AF) as relevant studies are scarce.

METHODS

We searched through the PubMed, EMBASE, and Cochrane Library databases for prospective observational studies (POSs) or randomised controlled trials (RCTs) comparing UI-NOAC versus MI-NOAC from their establishment to January 2020. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to compare the pooled treatment effect.

RESULTS

Nine studies (three POSs and six RCTs) with 2578 patients were included in the final analysis (55% patients received MI-NOAC). No significant difference was found regarding the risk of major bleeding (OR 0.92, 95% CI 0.43-2.00, P = .84, I²   = 0%). Both groups were comparable in all subgroups ([Asians: OR 1.00, 95% CI 0.43-2.36, P = .99, I²   = 0%], [non-Asians: OR 0.64, 95% CI 0.11-3.88, P = .63, I²   = 0%], [RCTs: OR 0.85, 95% CI 0.37-1.97, P = .71, I²   = 0%], and [POSs: OR 0.52, 95% CI 0.19-12.01, P = .69, I²   = 0%]). The risk of minor bleeding (P = .88) or stroke (P = .69) was comparable between the groups. UI-NOAC resulted in a significant reduction in silent stroke (SS) (OR 0.44, 95% CI 0.23-0.83, P = .01, I²   = 72%). No significant difference was found in SS between once-daily and twice-daily NOACs (OR 0.91, 95% CI 0.63-1.33, P = .64, I²   = 0%) in the MI-NOAC group.

CONCLUSIONS

UI-NOAC, as a peri-procedural anticoagulation strategy for catheter ablation in AF, had similar safety compared with MI-NOAC, but was advantageous in terms of SS.

An engineered factor Va prevents bleeding induced by direct-acting oral anticoagulants by different mechanisms

Control of bleeding with direct-acting oral anticoagulants (DOACs) remains an unmet clinical need. Activated superFactor V (superFVa) is an engineered activated protein C (APC)-resistant FVa variant with enhanced procoagulant activity resulting from an A2/A3 domain disulfide bond and was studied here for control of DOAC-induced bleeding. SuperFVa reversed bleeding induced by FXa inhibitors (rivaroxaban, apixaban), and the FIIa inhibitor dabigatran in BalbC mice. The blocking anti-protein C and APC [(A)PC] antibody SPC-54 also reduced FXa inhibitor induced bleeding similar to superFVa, whereas dabigatran-induced bleeding was not affected. This indicated that sufficient APC was generated to contribute to bleeding in the presence of FXa inhibitors, but not in the presence of dabigatran, suggesting that mechanisms contributing to bleeding differed for FXa and FIIa inhibitors. Despite different mechanisms contributing to bleeding, superFVa effectively reduced bleeding for all DOACs, indicating the versatility of superFVa's properties that contribute to its universal prohemostatic effects for DOAC associated bleeding. Supported by thrombin generation assays on endothelial cells in normal plasma spiked with DOACs and patient plasma anticoagulated with DOACs, 3 complementary mechanisms were identified by which superFVa achieved DOAC class-independent prohemostatic efficiency. These mechanisms are resistance to inactivation by APC, overcoming the FV activation threshold, and maximizing the efficiency of the prothrombinase complex when the available FXa is increased by FVIIa-based prohemostatics. In summary, it is this versatility of superFVa that delineates it from other prohemostatic agents as a promising class-independent rescue agent in bleeding situations associated with DOACs.

Meta-analysis of the safety and efficacy of using minimally interrupted novel oral anticoagulants in patients undergoing catheter ablation for atrial fibrillation

PURPOSE

The ideal periprocedural anticoagulation strategy for patients being treated with a novel oral anticoagulant (NOAC) during catheter ablation (CA) for atrial fibrillation (AF) is unclear. We evaluated the safety and efficacy of using a minimally interrupted NOAC strategy versus an uninterrupted NOAC or vitamin K antagonist (VKA) strategy during AF ablation.

METHODS

The Cochrane Library, PubMed, and EMBASE databases were searched for randomized controlled or prospective observational studies that compared a minimally interrupted NOAC strategy with an uninterrupted NOAC or VKA strategy from the time of database establishment up to December 2019. The primary endpoints were major bleeding, minor bleeding, and symptomatic thromboembolism. The secondary endpoint was silent cerebral infarction (SCI) as detected by post-ablation brain magnetic resonance imaging (MRI). A measurement of treatment effect for the endpoint was reported as pooled odds ratio (OR) with 95% confidence interval (CI).

RESULTS

A total of 18 studies (6 randomized, 11 observational, and 1 randomized registry) with 6203 patients were included in the final analysis (47% of the patients received minimally interrupted NOAC). There was no significant difference between treatment groups regarding the risk for major bleeding (OR 1.04, 95% CI 0.69-1.57, P = 0.86, I² = 27%). Different stratification methods did not yield significant difference regarding the risk for major bleeding. There was no difference between groups regarding the risk for minor bleeding (P = 1.00) or symptomatic thromboembolism (P = 0.26). Brain MRI results showed that both uninterrupted NOAC (OR 0.44, 95% CI 0.23-0.83, P = 0.01, I² = 72%) and uninterrupted VKA (OR 0.48, 95% CI 0.24-0.97, P = 0.04, I² = 36%) produced a significant reduction in the rate of SCI when compared with minimally interrupted NOAC.

CONCLUSIONS

A periprocedural anticoagulation strategy of minimally interrupted NOAC is not superior to uninterrupted NOAC or VKA when used during AF ablation. There is evidence favoring the use of uninterrupted NOAC or VKA in terms of the risk for SCI.

Emergency medicine misconceptions: Utility of routine coagulation panels in the emergency department setting

BACKGROUND

Coagulation panels are ordered for a variety of conditions in the emergency department (ED).

OBJECTIVE

This narrative review evaluates specific conditions for which a coagulation panel is commonly ordered but has limited utility in medical decision-making.

DISCUSSION

Coagulation panels consist of partial thromboplastin time (PTT) or activated partial thromboplastin time (aPTT), prothrombin time (PT), and international normalized ratio (INR). These tests evaluate the coagulation pathway which leads to formation of a fibrin clot. The coagulation panel can monitor warfarin and heparin therapy, evaluate for vitamin K deficiency, evaluate for malnutrition or severe systemic disease, and assess hemostatic function in the setting of bleeding. The utility of coagulation testing in chest pain evaluation, routine perioperative assessment, prior to initiation of anticoagulation, and as screening for admitted patients is low, with little to no change in patient management based on results of these panels. Coagulation testing should be considered in systemically ill patients, those with a prior history of bleeding or family history of bleeding, patients on anticoagulation, or patients with active hemorrhage and signs of bleeding. Thromboelastography and rotational thromboelastometry offer more reliable measures of coagulation function.

CONCLUSIONS

Little utility for coagulation assessment is present for the evaluation of chest pain, routine perioperative assessment, initiation of anticoagulation, and screening for admitted patients. However, coagulation panel assessment should be considered in patients with hemorrhage, patients on anticoagulation, and personal history or family history of bleeding.

The prognostic utility of ICH-score in anticoagulant related intracerebral hemorrhage

Although intracerebral hemorrhage (ICH) score is used to provide an estimate on the probability of mortality following spontaneous ICH of any cause, its utility has not been exclusively tested in ICH patients with history of treatment with vitamin K antagonists (VKAs) or non-vitamin K oral anticoagulants (NOACs). The aim of the present report is to investigate the utility of ICH score for mortality prognostication of VKA-ICH and NOAC-ICH patients. We used receiver operating characteristic curve analyses to estimate the accuracy parameters for the different values of ICH score in the prognosis of mortality within 30-days after the onset of NOAC-ICH or VKA-ICH. We analyzed data from 108 NOAC-ICH and 241 VKA-ICH patients (median age 76 years, 58% males, median NIHSS score 11 points, median ICH-score 2 points). ICH score of 4 points was uncovered to be the most favorable threshold for the prediction of 30-day mortality both after NOAC-ICH (sensitivity: 57.7%, specificity: 98.8%) or VKA-ICH (sensitivity: 42.1%, specificity: 92.6%). However, comparison of the areas under the curve (AUC) suggested a cumulatively higher (p = .001) predictive value of ICH-score in the prognostication of 30-day mortality after ICH related to the use of NOACs (AUC: 0.92, 95%CI: 0.86-0.98) compared to the ICH related to the use of VKAs (AUC: 0.77, 95%CI: 0.70-0.83). In conclusion, ICH score seems to have an adequate predictive utility in the prognostication of 30-day mortality following an ICH related to the use of oral anticoagulants, with better yield in ICH cases associated with the use of NOACs.

Patients on NOACs in the Emergency Room

PURPOSE OF REVIEW

Despite the increasing use of NOACs, there is still uncertainty on how to treat NOAC patients presenting with neurological emergencies. Initial assessment of coagulation status is challenging but essential in these patients to provide best-possible treatment in case of ischemic or hemorrhagic stroke. Meanwhile, anticoagulation reversal strategies have been suggested; yet, the optimal management is still unestablished. The current review aims to provide up-to-date information on (i) how to identify patients with NOAC intake, (ii) which therapies are feasible in the setting of ischemic and hemorrhagic stroke as well as traumatic intracranial hemorrhage, and (iii) how to proceed with patients requiring emergency lumbar puncture.

RECENT FINDINGS

Despite several expert opinions, there is still an ongoing debate which NOAC patients presenting with ischemic stroke may benefit from recanalizing strategies and whether these treatment approaches can be performed safely. Results from two phase IV trials investigating the efficacy of NOAC-specific reversal agents in case of major bleeding seem promising with regard to hemostatic parameters, but these antidotes have not been verified to clinically benefit patients, and approval by authorities in parts is still pending. Specific reversal agents are on the way and will provide new treatment options in patients with NOAC-related ischemic and hemorrhagic stroke. Up to now, the decision which patients should undergo recanalizing treatment for ischemic stroke, or which specific pharmacological reversal treatment in hemorrhagic stroke should be initiated, has to be made cautiously on an individual basis after assessing hemostatic parameters.

Evaluation of the Effect of Apixaban on INR in the Inpatient Population

Direct oral anticoagulants (DOACs), particularly direct factor Xa inhibitors, have been associated with prolongation of the prothrombin time and the international normalized ratio (INR). Although DOACs do not require monitoring, elevations in the INR have been reported in in vitro and observational studies. The literature surrounding the extent of elevation and the clinical significance is limited. The objective of this study was to quantify the degree of INR elevation in hospitalized patients receiving apixaban. This was a single-center, retrospective, observational analysis of adult patients who received at least 1 dose of apixaban during their hospital admission and had at least 1 INR sample collected prior to and following administration. The major end point of this study was to characterize the effect of apixaban on the INR by determining the percentage of patients with an INR higher than our laboratory defined normal (defined as INR > 1.1). Minor end point outcomes included the incidence of an INR increase >0.3 from baseline INR and additional patient-specific factors that may influence INR elevation. Seventy-nine patients were included in the analysis. On day 1 of therapy, the median (interquartile range, IQR) INR was 1.4 (1.3:1.6) with 84.5% of patients having an elevated INR. The median (IQR) INR increased to 1.5 (1.4:1.6) and 1.7 (1.5:1.9) on day 4 and day 7, respectively. Of patients whose INR increased by more than 0.3, the median (IQR) change in INR from baseline was 0.5 (0.4:0.6). Apixaban is associated with a notable increase in INR in hospitalized patients, although it is not clear the clinical impact of the increase. Although literature does not support monitoring INR as a marker of apixaban activity, it is important for clinicians to understand the association apixaban has on the INR to avoid inappropriate interpretation of routine coagulation assays.

Quantitative Detection of Digoxin in Plasma Using Small-Molecule Immunoassay in a Recyclable Gravity-Driven Microfluidic Chip

Immunoassays are critical for clinical diagnostics and biomedical research. However, two major challenges remaining in conventional immunoassays are precise quantification and development of immunoassays for small-molecule detection. Here, a two signal-mode small-molecule immunoassay containing an internal reference that provides high stability and reproducibility compared to conventional small-molecule immunoassays is presented. A system is developed for quantitative monitoring of the digoxin concentration in plasma in the clinically relevant range (0.6-2.6 nm). Furthermore, the model system is integrated into a simple gravity-driven microfluidic chip (G-Chip) requiring only 10 µL plasma. The G-Chip allows fast detection without any complex operation and can be recycled for at least 50 times. The assay, and the G-Chip in particular, has the potential for further development of point-of-care (POC) diagnostics.

In Vitro Selection of Specific DNA Aptamers Against the Anti-Coagulant Dabigatran Etexilate

Dabigatran Etexilate (PRADAXA) is a new oral anticoagulant increasingly used for a number of blood thrombosis conditions, prevention of strokes and systemic emboli among patients with atrial fibrillation. It provides safe and adequate anticoagulation for prevention and treatment of thrombus in several clinical settings. However, anticoagulation therapy can be associated with an increased risk of bleeding. There is a lack of specific laboratory tests to determine the level of this drug in blood. This is considered the most important obstacles of using this medication, particularly for patients with trauma, drug toxicity, in urgent need for surgical interventions or uncontrolled bleeding. In this work, we performed Systematic evolution of ligands by exponential enrichment (SELEX) to select specific DNA aptamers against dabigatran etexilate. Following multiple rounds of selection and enrichment with a randomized 60-mer DNA library, specific DNA aptamers for dabigatran were selected. We investigated the affinity and specificity of generated aptamers to the drug showing dissociation constants (Kd) ranging from 46.8-208 nM. The most sensitive aptamer sequence was selected and applied in an electrochemical biosensor to successfully achieve 0. 01 ng/ml level of detection of the target drug. With further improvement of the assay and optimization, these aptamers would replace conventional antibodies for developing detection assays in the near future.

Nonvitamin K Oral Anticoagulants in Patients With Atrial Fibrillation and Severe Renal Dysfunction

Both atrial fibrillation (AF) and chronic kidney disease (CKD) are highly prevalent, especially with increasing age and associated comorbidities, such as hypertension, diabetes, heart failure, and vascular disease. The relationship between both AF and CKD seems to be bidirectional: CKD predisposes to AF while onset of AF seems to lead to progression of CKD. Stroke prevention is the cornerstone of AF management, and AF patients with CKD are at higher risk of stroke, mortality, cardiac events, and bleeding. Stroke prevention requires use of oral anticoagulants, which are either vitamin K antagonists (eg, warfarin), or the nonvitamin K antagonist oral anticoagulants (NOACs). While NOACs have been shown to be effective in mild-to-moderate renal dysfunction, there are a paucity of data regarding NOACs in severe and end-stage renal dysfunction. This review first discusses the evidence for NOACs in CKD. Second, we summarize the current knowledge regarding the efficacy and safety of NOACs to prevent AF-related stroke and systemic embolism in severe and end-stage renal disease.

Hospital admissions for bleeding events associated with treatment with apixaban, dabigatran and rivaroxaban

Objectives

To analyse the hospital admissions for bleeding events associated with treatment with direct oral anticoagulants (DOACs). To describe the characteristics and outcomes of those patients.

Methods

A retrospective observational study was carried out in the framework of an integral risk management plan of drugs and proactive pharmacovigilance of hospital admissions for bleeding associated with apixaban, dabigatran and rivaroxaban from April 2015 through December 2016. Cases were identified using the information management tool of Orion Clinic (hospital electronic medical history) and by reviewing the hospital discharge reports. Various biometric, clinical and pharmacotherapeutic variables of each patient were registered.

Results

37 hospitalisation episodes for DOAC-induced bleeding in 32 patients (15 received rivaroxaban, 9 apixaban and 8 dabigatran) were detected, representing an incidence rate of 3.44 per 100 person-years (95% CI 2.35 to 4.86). The most common bleeding site was gastrointestinal (27 cases, 73.0%). Intracranial bleeding was rare (three cases, 8.1%). Four patients (12.5%) were receiving DOACs at full doses and had a 'dose reduction indication'. The mean (SD) length of stay was 8.4 (5.2) days. Three patients (8.1%) died during the hospitalisation. Among bleeding episodes without fatal outcome, DOACs were stopped in 14 cases, continued in 14 cases, switched for another DOAC in two cases and the dose was reduced in four cases.

Conclusions

DOACs are associated with serious bleeding events that require hospitalisation. The risk/benefit ratio assessment considering patient preferences and an individualised follow-up, especially in patients who are elderly, polymedicated or have impaired renal function, can help to reinforce the safe use of DOACs.

Bleeding-related hospital admissions and 30-day readmissions in patients with non-valvular atrial fibrillation treated with dabigatran versus warfarin

Essentials Bleeding is a common cause of hospital admission and readmission in oral anticoagulant users. Patients with dabigatran and warfarin were included to assess hospital admission risk. Dabigatran users had a higher risk of 30-day readmission with bleeding than warfarin users. Close monitoring following hospital discharge for dabigatran-related bleeding is warranted.

SUMMARY

Background Reducing 30-day hospital readmission is a policy priority worldwide. Warfarin-related bleeding is among the most common cause of hospital admissions as a result of adverse drug events. Compared with warfarin, dabigatran achieves a full anticoagulation effect more quickly following its initiation; hence it may lead to early-onset bleeds. Objectives To compare the incidence of bleeding-related hospital admissions and 30-day readmissions with dabigatran vs. warfarin in patients with non-valvular atrial fibrillation (NVAF). Methods This was a retrospective cohort study using a population-wide database managed by the Hong Kong Hospital Authority. Patients newly diagnosed with NVAF from 2010 through to 2014 and prescribed dabigatran or warfarin were 1:1 matched by propensity score. The incidence rate of hospital admission with bleeding (a composite of gastrointestinal bleeding, intracranial hemorrhage and bleeding at other sites) was assessed. Results Among the 51 946 patients with NVAF, 8309 users of dabigatran or warfarin were identified, with 5160 patients matched by propensity score. The incidence of first hospitalized bleeding did not differ significantly between groups (incidence rate ratio, 0.92; 95% confidence interval [CI], 0.66-1.28). Among patients who were continuously prescribed their initial anticoagulants upon discharge, dabigatran use was associated with a higher risk of 30-day readmission with bleeding over warfarin (adjusted hazard ratio, 2.87; 95%CI, 1.10-7.43). Conclusion When compared with warfarin, dabigatran was associated with a comparable incidence of first hospital admission but a higher risk of 30-day redmission with respect to bleeding. Close early monitoring of patients initiated on dabigatran following hospital discharge for bleeding is warranted.

The anticoagulant effect of heparin during radiofrequency ablation (RFA) in patients taking apixaban or rivaroxaban

PURPOSE

Measuring the anticoagulant effect of heparin during radiofrequency ablation (RFA) in patients taking apixaban and rivaroxaban is challenging, since the activated coagulation time (ACT) does not seem to reflect the true anticoagulant activity of these drugs. We therefore evaluated coagulation properties of apixaban and rivaroxaban during RFA by different coagulation assays to better monitor periprocedural hemostasis.

METHODS

The study included 90 patients (61 ± 12 years) with atrial fibrillation who underwent RFA procedures. Patients received 20 mg rivaroxaban (n = 73) once or 5 mg apixaban (n = 17) twice daily 4 weeks prior to the procedure. During RFA, unfractionated heparin i.v. was given to maintain an ACT of 250-300 s. Blood samples were taken before and 10, 60, and 360 min after heparin administration.

RESULTS

Heparin displayed a lower anti-Xa activity in rivaroxaban-treated patients compared to apixaban-treated patients. In contrast, D-dimer and prothrombin fragment F1+2 plasma levels indicated a higher activation of the coagulation cascade in apixaban/heparin than in rivaroxaban/heparin patients. This discordant coagulative state measured in vitro had no clinical impact in terms of bleeding or thromboembolic complications.

CONCLUSION

We found different biochemical responses to rivaroxaban/heparin and apixaban/heparin during RFA. Precaution is necessary when monitoring periprocedural hemostasis in DOAC patients to avoid mismanagement.

Recent advances in the treatment of venous thromboembolism in the era of the direct oral anticoagulants

The direct oral anticoagulants (DOACs) have now supplanted vitamin K antagonists (VKAs) for the treatment of venous thromboembolism (VTE). The DOACs include dabigatran, which inhibits thrombin, and rivaroxaban, apixaban, and edoxaban, which inhibit factor Xa. The DOACs are as effective for the prevention of recurrence as conventional VTE treatment, consisting of a parenteral anticoagulant followed by a VKA, and are associated with less bleeding. Because of these properties and the convenience of fixed dosing without the need for routine coagulation monitoring, guidelines now recommend DOACs over VKAs for VTE treatment in patients without active cancer. This paper examines the increasing role of the DOACs for VTE treatment.

Anticoagulation Bridge Therapy in Patients with Atrial Fibrillation: Recent Updates Providing a Rebalance of Risk and Benefit

In 2011 we reviewed clinical updates and controversies surrounding anticoagulation bridge therapy in patients with atrial fibrillation (AF). Since then, options for oral anticoagulation have expanded with the addition of four direct oral anticoagulant (DOAC) agents available in the United States. Nonetheless, vitamin K antagonist (VKA) therapy continues to be the treatment of choice for patients who are poor candidates for a DOAC and for whom bridge therapy remains a therapeutic dilemma. This literature review identifies evidence and guideline and consensus statements from the last 5 years to provide updated recommendations and insight into bridge therapy for patients using a VKA for AF. Since our last review, at least four major international guidelines have been updated plus a new consensus document addressing bridge therapy was released. Prospective trials and one randomized controlled trial have provided guidance for perioperative bridge therapy. The clinical trial data showed that bridging with heparin is associated with a significant bleeding risk compared with not bridging; furthermore, data suggested that actual perioperative thromboembolic risk may be lower than previously estimated. Notably, patients at high risk for stroke have not been adequately represented. These findings highlight the importance of assessing thrombosis and bleeding risk before making bridging decisions. Thrombosis and bleeding risk tools have emerged to facilitate this assessment and have been incorporated into guideline recommendations. Results from ongoing trials are expected to provide more guidance on safe and effective perioperative management approaches for patients at high risk for stroke.

The Use of 3- and 4-Factor Prothrombin Complex Concentrate in Patients With Elevated INR

BACKGROUND

PCC (Kcentra®) is an Food and Drug Administration (FDA)-approved 4-factor PCC used for the treatment of warfarin-related coagulopathy (WRC), but it has also been used off-label to treat non-WRC. Three-factor PCC in the form of coagulation factor IX human (Bebulin®) has also been used for WRC and off-label to treat non-WRC. It is unclear whether the use of 3- or 4-factor PCCs is effective for the treatment of non-WRC,.

OBJECTIVE

Our aim is to characterize the use of 3- and 4-factor PCCs for patients identified with a non-WRC.

METHODS

A retrospective analysis of patients who received PCCs for both WRC and non-WRC between January 2012 and July 2015 was conducted.

RESULTS

A total of 187 patients with elevated international normalized ratio (INR) who received PCCs were analyzed; 53.9% of patients in the WRC group and 27.7% in the non-WRC group corrected to an INR of 1.3 or less after 3- or 4-factor PCC administration. In those patients with non-WRC and who had underlying liver disease, 3- and 4-factor PCCs reduced mean INR by 0.98 and 1.43, respectively.

CONCLUSION

Three and 4-factor PCCs can reduce INR in patients with WRC and in those with non-WRC secondary to liver disease.

Applying the Cell-Based Coagulation Model in the Management of Critical Bleeding

The cell-based coagulation model was proposed 15 years ago, yet has not been applied commonly in the management of critical bleeding. Nevertheless, this alternative model may better explain the physiological basis of current coagulation management during critical bleeding. In this article we describe the limitations of the traditional coagulation protein cascade and standard coagulation tests, and explain the potential advantages of applying the cell-based model in current coagulation management strategies. The cell-based coagulation model builds on the traditional coagulation model and explains many recent clinical observations and research findings related to critical bleeding unexplained by the traditional model, including the encouraging results of using empirical 1:1:1 fresh frozen plasma:platelets:red blood cells transfusion strategy, and the use of viscoelastic and platelet function tests in patients with critical bleeding. From a practical perspective, applying the cell-based coagulation model also explains why new direct oral anticoagulants are effective systemic anticoagulants even without affecting activated partial thromboplastin time or the International Normalized Ratio in a dose-related fashion. The cell-based coagulation model represents the most cohesive scientific framework on which we can understand and manage coagulation during critical bleeding.

Diffuse Alveolar Hemorrhage Associated with Edoxaban Therapy

Introduction. The main adverse effect of anticoagulant therapy is bleeding, and major bleeding, including intracranial, gastrointestinal, and retroperitoneal bleeding, has been reported as an adverse effect of edoxaban, a direct oral anticoagulant (DOAC). Bleeding during systemic anticoagulation with edoxaban presents a therapeutic conundrum, because there is currently no safe or efficacious reversal agent to stop major bleeding. Case Report. A 51-year-old woman had multiple traumatic injuries, including lower limb fractures. On day 8, she developed deep venous thrombosis, and edoxaban was administered orally. On day 38, she developed fungemia, which was treated with an antifungal drug. On day 43, she presented with dyspnea. Chest computed tomography scan showed bilateral diffuse ground-glass opacities in the whole lung fields. The results of the subsequent workup (i.e., serum levels of the antineutrophil cytoplasmic antibody, antinuclear antibody, and antiglomerular basement membrane antibody) and microbiological study were unremarkable. Based on these findings, her condition was diagnosed as diffuse alveolar hemorrhage (DAH) associated with edoxaban therapy. The lung opacities disappeared spontaneously after edoxaban therapy was discontinued. Conclusion. DAH is a dangerous complication associated with edoxaban therapy. DOACs, including edoxaban, should be prescribed with caution, especially for patients in a critical condition.

Direct oral anticoagulant drug level testing in clinical practice: A single institution experience

We performed a review of all direct oral anticoagulant (DOAC) levels - ecarin times for dabigatran and anti-Xa levels for rivaroxaban and apixaban - ordered at our institution with the purpose of evaluating DOAC levels from "real-world" (non-clinical trial) patients taking DOACs long-term, in order to assess levels obtained, reasons for checking levels, and actions taken based on the testing result. A total of 28 patients had 48 levels sent over a 36-month period. The majority of outpatient levels were within or close to the range of published values. The setting in which levels were sent influenced how results affected management decisions: in the outpatient setting, the majority of levels served to reassure clinicians that DOAC levels were within expected ranges resulting in continuation of chosen management, whereas in the inpatient setting, DOAC levels were used most frequently to detect DOAC presence in urgent clinical situations and influenced clinical decision-making in the peri-procedural and pre-operative periods. Our results demonstrate that while testing may be useful if immediately available in urgent clinical situations where assessment of drug presence is needed, DOAC level monitoring is infrequently used overall, and the lack of use combined with the paucity of available evidence to guide clinical decision-making based on the results suggests there is little urgency to make the tests widely available for routine use outside of acute settings in the emergency department and urgent surgical setting.

Reversing anticoagulant effects of novel oral anticoagulants: role of ciraparantag, andexanet alfa, and idarucizumab

Novel oral anticoagulants (NOACs) are increasingly used in clinical practice, but lack of commercially available reversal agents is a major barrier for mainstream use of these therapies. Specific antidotes to NOACs are under development. Idarucizumab (aDabi-Fab, BI 655075) is a novel humanized mouse monoclonal antibody that binds dabigatran and reverses its anticoagulant effect. In a recent Phase III study (Reversal Effects of Idarucizumab on Active Dabigatran), a 5 g intravenous infusion of idarucizumab resulted in the normalization of dilute thrombin time in 98% and 93% of the two groups studied, with normalization of ecarin-clotting time in 89% and 88% patients. Two other antidotes, andexanet alfa (PRT064445) and ciraparantag (PER977) are also under development for reversal of NOACs. In this review, we discuss commonly encountered management issues with NOACs such as periprocedural management, laboratory monitoring of anticoagulation, and management of bleeding. We review currently available data regarding specific antidotes to NOACs with respect to pharmacology and clinical trials.

Novel antidotes for target specific oral anticoagulants

Target specific oral anticoagulants (dabigatran, rivaroxaban, apixaban, and edoxaban) are changing the landscape of anticoagulation. The major drawback is the absence of an effective antidote for severe bleedings and/or prior to procedures. Currently there are a few promising antidotes undergoing clinical trials. This review summarized the latest development in idarucizumab, andexanet alpha and PER977.