Point-of-care testing of coagulation in patients treated with edoxaban

Rapid assessment of direct oral anticoagulants in acute stroke-An educational systematic review

PURPOSE

To provide an overview on commercially available point-of-care tests (POCT) for rapid assessment of direct oral anticoagulant (DOAC) activity, their diagnostic accuracy in identifying blood samples containing clinically relevant DOAC concentrations, and guidance on selecting the appropriate POCT system/assay for decision-making in emergencies.

METHODS

Systematic review with PubMed and Cochrane library search for published studies until September 6, 2024. Papers were included if in English, original research using blood samples from DOAC patients and POCT was implemented. Two reviewers assessed studies for eligibility and quality. Data from studies were aggregated and diagnostic accuracy at DOAC plasma thresholds of 30/50/100 ng/ml was recalculated.

FINDINGS

16 studies involving four commercially available POCT systems/assays were identified. Eleven studies evaluated blood-based POCT and five used urine for indirect estimation of DOAC plasma levels.

DISCUSSION

DOAC Dipsticks do not require knowledge about the taken DOAC, but measure urine and, due to low specificity, require blood testing in case of positive results. Hemochron Signature Elite (HSE) and CoaguChek use global coagulation assays and provide high sensitivity for edoxaban and rivaroxaban, HSE additionally for dabigatran. Due to insufficient correlation, both POCT are not recommended for apixaban, CoaguChek also not for dabigatran. The thromboelastometric ClotPro performs well for all DOAC, does not require knowledge about the DOAC, but was taken off the market recently.

CONCLUSION

Studies have shown feasibility of POCT in identifying blood samples containing clinically relevant DOAC plasma concentrations. Each POCT device has its own unique limitations. Knowledge about the POCT assays, time since last intake and type of DOAC enhances confidence in making appropriate therapeutic decisions. We propose an algorithm that could help guiding physicians in selecting an appropriate POCT system/assay in DOAC-related emergencies.

Predictors and Outcomes of Inappropriate Dosing of Direct Oral Anticoagulants in Patients Receiving Transcatheter Aortic Valve Implantation

INTRODUCTION

Direct oral anticoagulant (DOAC) dose adjustment is based on age, renal function, and body weight. There is a paucity of data describing the factors associated with the prescription of inappropriate dosage and their impact on clinical outcomes among patients receiving transcatheter aortic valve implantation (TAVI).

METHODS

In a single-center study, 432 patients who were on long-term DOAC therapy and underwent TAVI between 2015 and 2022 were included. We analyzed the predictors and outcomes of inappropriate dosing of DOACs; namely apixaban, dabigatran, edoxaban, and rivaroxaban. A composite endpoint, including all-cause mortality, life-threatening/major bleeding, stroke, peripheral thromboembolic complications, or myocardial infarction, was assessed after 1 year.

RESULTS

In this TAVI cohort, inappropriate DOAC dosing was observed in 20.6% of patients. Inappropriate DOAC dosage was related to female gender (adj. odds ratio [OR] 2.72, 95% confidence interval [CI] 1.64-4.51, p < 0.001) as well as lower estimated glomerular filtration rate (eGFR) (adj. OR 0.99, 95% CI 0.98-1.00, p = 0.019), and to the administration of non-rivaroxaban DOACs (adj. OR 0.28, 95% CI 0.16-0.50, p < 0.001). After 1 year, patients on both appropriate and inappropriate DOAC dosage exhibited comparable rates of the composite endpoint (OR 0.88, 95% CI 0.53-1.46, p = 0.622). Old age (adj. OR 1.05, 95% CI 1.01-1.10, p = 0.018) as well as anemia (adj. OR 0.86, 95% CI 0.75-0.99, p = 0.031) emerged as independent predictors of the composite endpoint.

CONCLUSIONS

In this TAVI cohort, female gender and renal insufficiency were associated with inappropriate DOAC dosage, whereas rivaroxaban was linked to appropriate dosing. Inadequate DOAC dosage did not translate into a worse outcome in our TAVI population.

TRIAL REGISTRATION

Prospective Segeberg TAVI Registry (ClinicalTrials.gov identifier: NCT03192774).

Assessing mortality and safety of IV thrombolysis in ischemic stroke patients on direct oral anticoagulants (DOACs): A systematic review and meta-analysis

BACKGROUND

Intravenous thrombolysis (IVT) is considered a standard reperfusion therapy for acute ischemic stroke (AIS) patients presenting within 4.5 hours of the last known well (LKW). Current guidelines contraindicate the use of IVT in patients within the window who are on Direct Oral Anticoagulants (DOACs) and took their last dose within 48 hours of presentation, due to a risk of symptomatic intracranial hemorrhage (sICH).

OBJECTIVE

To assess the safety of IVT as management of AIS in patients who take DOACs.

METHODS

A thorough literature search of four databases (PubMed, Scopus, Medline, Google Scholar, Web of science and ScienceDirect) was done from inception until May 2023. Double-arm studies that reported outcomes of mortality, sICH, and mRS scores were selected. Results from these studies were presented as odds ratios (ORs) with 95 % confidence intervals (CIs) and were pooled using a random-effects model.

RESULTS

Four eligible studies were included with a total of 238,425 stroke patients who underwent IVT (3330 in the DOAC arm and 235,217 in the placebo arm). The group with prior DOAC intake showed a significant decrease in sICH development and an increase in functional independence at 90 days compared to the control group. No significant association was seen between prior DOAC use and any serious alteplase-related complication within 36 hours, serious systemic or life-threatening hemorrhage within 36 hours, mortality within 3 months, or mRS score at 3 months.

CONCLUSION

The pooled analysis suggests that IVT is a safe management option for acute ischemic stroke in patients with DOAC intake before symptom onset without an increased risk of serious adverse events.

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.

Intravenous Thrombolysis in Patients With Ischemic Stroke and Recent Ingestion of Direct Oral Anticoagulants

Importance

International guidelines recommend avoiding intravenous thrombolysis (IVT) in patients with ischemic stroke who have a recent intake of a direct oral anticoagulant (DOAC).

Objective

To determine the risk of symptomatic intracranial hemorrhage (sICH) associated with use of IVT in patients with recent DOAC ingestion.

Design, Setting, and Participants

This international, multicenter, retrospective cohort study included 64 primary and comprehensive stroke centers across Europe, Asia, Australia, and New Zealand. Consecutive adult patients with ischemic stroke who received IVT (both with and without thrombectomy) were included. Patients whose last known DOAC ingestion was more than 48 hours before stroke onset were excluded. A total of 832 patients with recent DOAC use were compared with 32 375 controls without recent DOAC use. Data were collected from January 2008 to December 2021.

Exposures

Prior DOAC therapy (confirmed last ingestion within 48 hours prior to IVT) compared with no prior oral anticoagulation.

Main Outcomes and Measures

The main outcome was sICH within 36 hours after IVT, defined as worsening of at least 4 points on the National Institutes of Health Stroke Scale and attributed to radiologically evident intracranial hemorrhage. Outcomes were compared according to different selection strategies (DOAC-level measurements, DOAC reversal treatment, IVT with neither DOAC-level measurement nor idarucizumab). The association of sICH with DOAC plasma levels and very recent ingestions was explored in sensitivity analyses.

Results

Of 33 207 included patients, 14 458 (43.5%) were female, and the median (IQR) age was 73 (62-80) years. The median (IQR) National Institutes of Health Stroke Scale score was 9 (5-16). Of the 832 patients taking DOAC, 252 (30.3%) received DOAC reversal before IVT (all idarucizumab), 225 (27.0%) had DOAC-level measurements, and 355 (42.7%) received IVT without measuring DOAC plasma levels or reversal treatment. The unadjusted rate of sICH was 2.5% (95% CI, 1.6-3.8) in patients taking DOACs compared with 4.1% (95% CI, 3.9-4.4) in control patients using no anticoagulants. Recent DOAC ingestion was associated with lower odds of sICH after IVT compared with no anticoagulation (adjusted odds ratio, 0.57; 95% CI, 0.36-0.92). This finding was consistent among the different selection strategies and in sensitivity analyses of patients with detectable plasma levels or very recent ingestion.

Conclusions and Relevance

In this study, there was insufficient evidence of excess harm associated with off-label IVT in selected patients after ischemic stroke with recent DOAC ingestion.

Comparison of the DOAC Dipstick Test on Urine Samples With Chromogenic Substrate Methods on Plasma Samples in Outpatients Treated With Direct Oral Anticoagulants

Identifying adherence to direct oral anticoagulants (DOACs) plays a major role in treatment efficacy and safety. The DOAC Dipstick can detect DOACs in urine samples of acutely diseased patients at plasma thresholds of about 30 ng/mL. A prospective observational consecutive cohort study was performed on outpatients taking DOACs. The presence of direct oral factor Xa inhibitors (DXIs) in patient urine samples were independently evaluated by visual interpretation of the DOAC Dipstick pad colors. DOAC plasma concentration was assessed using STA®-Liquid Anti-Xa and STA®-Liquid Anti-IIa chromogenic substrate assays. Positive DOAC Dipstick results were compared with a threshold plasma of DOAC concentration ≥30 ng/mL. Of 120 patients (age 55.4  +  16.1 years, female n  =  63), 77 were on rivaroxaban and 43 on apixaban. Plasma concentrations were 129  ±  118 ng/mL for rivaroxaban, and 163  ±  130 ng/mL for apixaban, DOAC Dipstick test has a sensitivity of 97.2% and a positive predictive value of 89.5% at 30 ng/mL. No differences occurred between DXIs. Specificity and negative predictive value could not be determined due to the low number of true negative values. There were no differences in the interpretation of rivaroxaban and apixaban pad colors between observers (Kappa 1.0). Results show that DOAC Dipstick may be a useful tool for identifying DXIs in urine samples in an outpatient setting at a plasma threshold ≥ 30 ng/mL. Further studies should include patients treated with dabigatran, vitamin K antagonists, or other anticoagulants.

Diagnostic Modalities in Critical Care: Point-of-Care Approach

The concept of intensive care units (ICU) has existed for almost 70 years, with outstanding development progress in the last decades. Multidisciplinary care of critically ill patients has become an integral part of every modern health care system, ensuing improved care and reduced mortality. Early recognition of severe medical and surgical illnesses, advanced prehospital care and organized immediate care in trauma centres led to a rise of ICU patients. Due to the underlying disease and its need for complex mechanical support for monitoring and treatment, it is often necessary to facilitate bed-side diagnostics. Immediate diagnostics are essential for a successful treatment of life threatening conditions, early recognition of complications and good quality of care. Management of ICU patients is incomprehensible without continuous and sophisticated monitoring, bedside ultrasonography, diverse radiologic diagnostics, blood gas analysis, coagulation and blood management, laboratory and other point-of-care (POC) diagnostic modalities. Moreover, in the time of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, particular attention is given to the POC diagnostic techniques due to additional concerns related to the risk of infection transmission, patient and healthcare workers safety and potential adverse events due to patient relocation. This review summarizes the most actual information on possible diagnostic modalities in critical care, with a special focus on the importance of point-of-care approach in the laboratory monitoring and imaging procedures.

Point-of-care testing for emergency assessment of coagulation in patients treated with direct oral anticoagulants including edoxaban

BACKGROUND

Direct oral anticoagulants (DOAC) including edoxaban are increasingly used for stroke prevention in atrial fibrillation. Despite treatment, annual stroke rate in these patients remains 1-2%. Rapid assessment of coagulation would be useful to guide thrombolysis or reversal therapy in this growing population of DOAC/edoxaban-treated stroke patients. Employing the Hemochron™ Signature Elite point-of-care test system (HC-POCT), clinically relevant plasma concentrations of dabigatran and rivaroxaban can be excluded in a blood sample. However, no data exists on the effect of edoxaban on HC-POCT results. We evaluated whether edoxaban plasma concentrations above the current treatment thresholds for thrombolysis or anticoagulation reversal (i.e., 30 and 50 ng/mL) can be ruled out with the HC-POCT.

METHODS

We prospectively studied patients receiving a first dose of edoxaban. Six blood samples were collected from each patient: before, 0.5, 1, 2, 8, and 24 h after drug intake. HC-POCT-based INR (HC-INR), activated clotting time (HC-ACT+ and HC-ACT-LR), activated partial thromboplastin time (HC-aPTT), and mass spectrometry for edoxaban plasma concentrations were performed at each time-point. We calculated correlations, receiver operating characteristics (ROC) and test-specific cut-offs for ruling out edoxaban concentrations > 30 and > 50 ng/mL in a blood sample.

RESULTS

One hundred twenty blood samples from 20 edoxaban-treated patients were analyzed. Edoxaban plasma concentrations ranged from 0 to 512 ng/mL. HC-INR/HC-ACT+/HC-ACT-LR/HC-aPTT ranged from 0.7-8.3/78-310 s/65-215 s/19-93 s, and Pearson's correlation coefficients showed moderate to very strong correlations with edoxaban concentrations (r = 0.95/0.79/0.70/0.60). With areas under the ROC curve of 0.997 (95% confidence interval: 0.991-0.971) and 0.989 (0.975-1.000), HC-INR most reliably ruled out edoxaban concentrations > 30 and > 50 ng/mL, respectively, and HC-INR results ≤1.5 and ≤ 2.1 provided specificity/sensitivity of 98.6% (91.2-99.9)/98.0% (88.0-99.9) and 96.8% (88.0-99.4)/96.5% (86.8-99.4).

CONCLUSIONS

Our study represents the first systematic evaluation of the HC-POCT in edoxaban-treated patients. Applying sufficiently low assay-specific cut-offs, the HC-POCT may not only be used to reliably rule out dabigatran and rivaroxaban, but also very low edoxaban concentrations in a blood sample. Because the assay-specific cut-offs were retrospectively defined, further investigation is warranted.

TRIAL REGISTRATION

ClinicalTrials.gov, registration number: NCT02825394 , registered on: 07/07/2016, URL.

Specific Point-of-Care Testing of Coagulation in Patients Treated with Dabigatran

BACKGROUND AND PURPOSE

 Accurate and rapid assessment of coagulation status is necessary to guide thrombolysis or reversal of anticoagulation in stroke patients, but commercially available point-of-care (POC) assays are not suited for coagulation testing in patients treated with direct oral anticoagulants (DOACs). We aimed to evaluate the direct thrombin monitoring (DTM) test card by Helena Laboratories (Texas, United States) for anti-IIa-specific POC coagulation testing, hypothesizing that its POC-ecarin clotting time (POC-ECT) accurately reflects dabigatran plasma concentrations.

METHODS

 A prospective single-center diagnostic study (ClinicalTrials.gov-identifier: NCT02825394) was conducted enrolling patients receiving a first dose of dabigatran and patients already on dabigatran treatment. Blood samples were collected before drug intake and 0.5, 1, 2, 8, and 12 hours after intake. POC-ECT was performed using whole blood (WB), citrated blood (CB), and citrated plasma (CP). Dabigatran plasma concentrations were determined by mass spectrometry.

RESULTS

 In total, 240 blood samples from 40 patients contained 0 to 275 ng/mL of dabigatran. POC-ECT with WB/CB/CP ranged from 20 to 186/184/316 seconds. Pearson's correlation coefficient showed a strong correlation between dabigatran concentrations and POC-ECT with WB/CB/CP (R2  = 0.78/0.90/0.92). Dabigatran concentrations >30 and >50 ng/mL (thresholds for thrombolysis, surgery, and reversal therapy according to clinical guidelines) were detected by POC-ECT with WB/CB/CP (>36/35/45 and >43/45/59 seconds) with 95/97/97 and 96/98/97% sensitivity, and 81/87/94 and 74/60/91% specificity.

CONCLUSION

 This first study evaluating DOAC-specific POC coagulation testing revealed an excellent correlation of POC-ECT with actual dabigatran concentrations. Detecting clinically relevant dabigatran levels with high sensitivity/specificity, the DTM assay represents a suitable diagnostic tool in acute stroke, hemorrhage, and urgent surgery.