Point-of-care international normalized ratio testing accelerates thrombolysis in patients with acute ischemic stroke using oral anticoagulants

Urine-based point-of-care testing for factor-Xa-inhibitors in acute ischemic stroke patients: a feasibility study

Introduction

Direct oral anticoagulants (DOACs) have become widely used in clinical practice for preventing thromboembolic events. Point-of-care testing methods, particularly those based on urine samples, offer a promising approach for rapid and accurate assessment of DOAC presence. This pilot study aims to evaluate the utility of a urine-based DOAC dipstick test as a point-of-care tool for identifying DOAB presence in acute ischemic stroke (AIS) or transient ischemic attack (TIA) patients.

Patients and methods

This prospective pilot study included patients with AIS/TIA eligible for DOAC-measurement. After exclusion of 3 patients, 23 patients with DOAC-intake (DOAC group; factor-Xa-inhibitors; n = 23) and 21 patients without DOAC-intake (control-group) remained for analyses. The urine-based DOAC dipstick test and parallel blood-based specific DOAC-level assessment were performed in all patients. Time-intervals of sampling urine/blood sampling and result of DOAC-test were recorded to analyze a potential time benefit based on dipstick evaluation.

Results

The urine-based DOAC dipstick test demonstrated high sensitivity (100%) and specificity (100%), correctly identifying all patients with anticoagulatory activity due to DOAC intake (i.e., anti-Xalevel ≥30 ng/mL). Moreover, the visual readout of the test provided semiquantitative information on drug-specific anti-Xa levels, showing a sensitivity of 83% and specificity of 93% to detect anti-Xa levels ≥120 ng/mL. The dipstick test exhibited a median time-benefit of 2:25 h compared to standard blood-based DOAC-level testing.

Discussion

The results of this pilot study underline the efficacy of urine-based point-of-care testing as a rapid and reliable method for assessing DOAC presence in patients with acute ischemic stroke.

Conclusion

The value of this tool for clinical decision-making in stroke management needs to be established in future trials.Clinical Trial Registration: Clinicaltrails.org identifier [NCT06037200].

Reducing Laboratory Turnaround Time in Patients With Acute Stroke and the Lack of Impact on Time to Reperfusion Therapy

CONTEXT.—

Timely reperfusion improves the recovery of patients with acute ischemic stroke. Laboratory results are crucial to guide treatment decisions in patients when abnormal laboratory tests are suspected.

OBJECTIVE.—

To implement a new laboratory workflow for acute stroke patients and compare laboratory turnaround time (TAT) preimplementation and postimplementation.

DESIGN.—

We conducted a retrospective pre-post intervention study of patients with suspected acute stroke during the 4-month periods before and after the implementation of a new laboratory workflow process. The improvement process included relocating the specimen registration site, laboratory notification before specimen arrival, a color-coding system on tubes, timing at all processes, and eliminating the smear review if platelets were normal. TATs of the laboratory and door-to-clinical intervention times before and after the improvement process were compared.

RESULTS.—

Postintervention, median specimen transportation time decreased from 11 (interquartile range [IQR], 8.4-16.4) to 9 minutes (IQR, 6.3-12.8), P < .001. The intralaboratory and total TATs of complete blood cell count, coagulation tests, and creatinine significantly decreased (P < .001 for all). Blood drawn-to-laboratory reported time decreased from 43 (IQR, 36.0-51.5) to 33 minutes (IQR, 29.2-35.8, P < .001). However, door-to-needle time for thrombolysis and door-to-puncture time and door-to-recanalization time for mechanical thrombectomy were not statistically different (P = .11, .69, and .50, respectively).

CONCLUSIONS.—

The new laboratory workflow significantly decreased transportation time, TAT of individual tests, and the blood drawn-to-laboratory reported time. However, the time to treatment of acute ischemic stroke patients was not different between preimplementation and postimplementation.

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.

Acute Stroke Treatment in an Anticoagulated Patient: When Is Thrombolysis an Option?

Purpose of Review

Direct oral anticoagulants (DOACs: the factor Xa inhibitors rivaroxaban, apixaban, and edoxaban and the direct thrombin inhibitor dabigatran) are the mainstay of stroke prevention in patients with non-valvular atrial fibrillation (AF). Nevertheless, there is a residual stroke risk of 1–2% per year despite DOAC therapy. Intravenous thrombolysis (IVT) reduces morbidity in patients with ischemic stroke and improves functional outcome. Prior DOAC therapy is a (relative) contraindication for IVT but emerging evidence supports its use in selected patients.

Recent Findings

Recent observational studies highlighted that IVT in patients on prior DOAC therapy seems feasible and did not yield major safety issues. Different selection criteria and approaches have been studied including selection by DOAC plasma levels, non-specific coagulation assays, time since last intake, and prior reversal agent use. The optimal selection process is however not clear and most studies comprised few patients.

Summary

IVT in patients taking DOAC is a clinically challenging scenario. Several approaches have been proposed without major safety issues but current evidence is weak. A patient-oriented approach balancing potential benefits of IVT (i.e., amount of salvageable penumbra) against expected bleeding risk including appropriate monitoring of anticoagulant activity seem justified.

Recanalisation therapies for acute ischaemic stroke in patients on direct oral anticoagulants

Direct oral anticoagulants (DOACs) have emerged as primary therapeutic option for stroke prevention in patients with atrial fibrillation. However, patients may have ischaemic stroke despite DOAC therapy and there is uncertainty whether those patients can safely receive intravenous thrombolysis or mechanical thrombectomy. In this review, we summarise and discuss current knowledge about different approaches to select patient. Time since last DOAC intake-as a surrogate for anticoagulant activity-is easy to use but limited by interindividual variability of drug pharmacokinetics and long cut-offs (>48 hours). Measuring anticoagulant activity using drug-specific coagulation assays showed promising safety results. Large proportion of patients at low anticoagulant activity seem to be potentially treatable but there remains uncertainty about exact safe cut-off values and limited assay availability. The use of specific reversal agents (ie, idarucizumab or andexanet alfa) prior to thrombolysis is a new emerging option with first data reporting safety but issues including health economics need to be elucidated. Mechanical thrombectomy appears to be safe without any specific selection criteria applied. In patients on DOAC therapy with large vessel occlusion, decision for intravenous thrombolysis should not delay thrombectomy (eg, direct thrombectomy or immediate transfer to a thrombectomy-capable centre recommended). Precision medicine using a tailored approach combining clinicoradiological information (ie, penumbra and vessel status), anticoagulant activity and use of specific reversal agents only if necessary seems a reasonable choice.

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.

Blood-Based Biomarkers Are Associated with Different Ischemic Stroke Mechanisms and Enable Rapid Classification between Cardioembolic and Atherosclerosis Etiologies

Stroke is a top leading cause of death, which occurs due to interference in the blood flow of the brain. Ischemic stroke (blockage) accounts for most cases (87%) and is further subtyped into cardioembolic, atherosclerosis, lacunar, other causes, and cryptogenic strokes. The main value of subtyping ischemic stroke patients is for a better therapeutic decision-making process. The current classification methods are complex and time-consuming (hours to days). Specific blood-based biomarker measurements have promising potential to improve ischemic stroke mechanism classification. Over the past decades, the hypothesis that different blood-based biomarkers are associated with different ischemic stroke mechanisms is increasingly investigated. This review presents the recent studies that investigated blood-based biomarker characteristics differentiation between ischemic stroke mechanisms. Different blood-based biomarkers are specifically discussed (b-type natriuretic peptide, d-dimer, c-reactive protein, tumor necrosis factor-α, interleukin-6, interleukin-1β, neutrophil-lymphocyte ratio, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein and apolipoprotein A), as well as the different cut-off values that may be useful in specific classifications for cardioembolic and atherosclerosis etiologies. Lastly, the structure of a point-of-care biosensor device is presented, as a measuring tool on-site. The information presented in this review will hopefully contribute to the major efforts to improve the care for stroke patients.

Imbalanced Regional Development of Acute Ischemic Stroke Care in Emergency Departments in China

Objective

Most patients of acute ischemic stroke (AIS) receive treatments in the department of emergency in China. We aimed to examine the status of AIS diagnosis and treatment and the impact of green pathway operation in different regions of China.

Methods

In this nationwide survey, information regarding the emergency care of AIS was collected from 451 hospitals in different regions of China, by interviewing 484 physicians from these hospitals. Structured questionnaire was used to explore the status of AIS care and impact of the green pathway.

Results

445 hospitals from 18 provinces, 4 municipalities, and 3 ethnic autonomous regions in China were included in the present study. Overall, the proportion of door-to-needle time (DNT) less than 60 min was 66.08% in the enrolled hospitals (n = 298). Stratified by regions, the results suggested that hospitals located in East regions had shorter DNT time (P=0.036), and more proportion of rtPA (P < 0.001) than those in West regions. Further analysis suggested that hospitals with a green channel were more likely to shorten DNT and improve the proportion of rtPA (P < 0.01).

Conclusion

Considerable regional differences were observed in terms of DNT time and thrombolysis rates in the departments of emergency in China. Further studies are required to confirm the regional differences in AIS care in China.

Benefits and Pitfalls of Point-of-Care Coagulation Testing for Anticoagulation Management: An ACLPS Critical Review

Objectives

Point-of-care (POC) testing is generally less precise and has higher reagent costs per test than laboratory-based assays. However, POC hemostasis testing can offer significant advantages in particular situations: patient-managed warfarin therapy as well as rapid turnaround time heparin management for intraoperative patients. Of note, POC hemostasis testing is generally approved for the purposes of anticoagulation monitoring and is inferior to laboratory coagulation testing for the diagnosis of congenital or acquired coagulopathy.

Methods

The frequently used POC coagulation instruments for POC international normalized ratio and activated clotting time are reviewed, as well as their typical performance relative to central laboratory testing (where available).

Results

Several cases are discussed that highlight the benefits, as well as pitfalls, of POC coagulation testing.

Conclusions

POC coagulation testing for anticoagulation monitoring offers advantages in particular situations. Clear policies and protocols must be developed to guide proper use of POC versus central laboratory hemostasis testing.

Non-Vitamin K Oral Anticoagulants Associated Bleeding and Its Antidotes

Oral anticoagulant-associated intracerebral hemorrhage (OAC-ICH) accounts for nearly 20% of all ICH. The number of patients with an indication for oral anticoagulant therapy (OAT) increases with increasing age. OAT became less complicate with the introduction of non-vitamin K oral anticoagulants (NOAC) OAT because of easier handling, favorable risk-benefit profile, reduced rates of ICH compared to vitamin K antagonists and no need for routine coagulation testing. Consequently, despite a better safety profile of NOAC the number of patients with OAC-ICH will increase. The mortality and complication rates of OAC-ICH are high and therefore they are the most feared complication of OAT. Immediate normalization of coagulation is the main goal and therefore knowledge of pharmacodynamics and coagulation status is essential. Laboratory measurements of anticoagulant activity in NOAC patients is challenging as specific tests are not widely available. More accessible tests such as the prothrombin time and activated partial thromboplastin time have important limitations. In dabigatran-associated ICH 5 g Idarucizumab should be administered. In rivaroxaban and apixaban-associated ICHs administration of andexanet alpha should be considered. Prothrombin complex concentrate may be considered if andexanet alpha is not available or in case of an ICH associated with edoxaban.

Point-of-care coagulation testing for reducing in-hospital delay in thrombolysis

Background:

The confirmation of prothrombin time international normalized ratio by a central laboratory often delays intravenous thrombolysis in patients with acute ischemic stroke.

Objectives:

We investigated the feasibility, reliability, and usefulness of point-of-care determination of prothrombin time international normalized ratio for stroke thrombolysis.

Methods:

Among 312 patients with ischemic stroke, 202 who arrived at the emergency room within 4.5 h of stroke onset were enrolled in the study. Patients with lost orders for point-of-care testing for the prothrombin time international normalized ratio or central laboratory testing for the prothrombin time international normalized ratio (n = 47) were excluded. We compared international normalized ratio values and the time interval from arrival to the report of test results (door-to-international normalized ratio time) between point-of-care testing for the prothrombin time international normalized ratio and central laboratory testing for the prothrombin time international normalized ratio. In patients who underwent thrombolysis, we compared the time interval from arrival to thrombolysis (door-to-needle time) between the current study population and historic cohort at our center.

Results:

In the 155 patients included in the study, the median door-to-international normalized ratio time was 9.0 min (interquartile range, 5.0–12.0 min) for point-of-care testing for the prothrombin time international normalized ratio and 46.0 min (interquartile range, 38.0–55.0 min) for central laboratory testing for the prothrombin time international normalized ratio (p < 0.001). The intraclass correlation coefficient between point-of-care testing for the prothrombin time international normalized ratio and central laboratory testing for the prothrombin time international normalized ratio was 0.975 (95% confidence interval: 0.966–0.982). Forty-nine of the 155 patients underwent intravenous thrombolysis. The door-to-needle time was significantly decreased after implementation of point-of-care testing for the prothrombin time international normalized ratio (median, 23.0 min; interquartile range, 16.0–29.8 vs median, 46.0 min; interquartile range, 33.5–50.5 min).

Conclusion:

Utilization of point-of-care testing for the prothrombin time international normalized ratio was feasible in the management of patients with acute ischemic stroke. Point-of-care testing for the prothrombin time international normalized ratio was quick and reliable and had a pivotal role in expediting thrombolysis.

Choosing a particular oral anticoagulant and dose for stroke prevention in individual patients with non-valvular atrial fibrillation: part 2

The choice of oral anticoagulant (OAC) for patients with atrial fibrillation (AF) may be influenced by individual clinical features or by patterns of risk factors and comorbidities. We reviewed analyses of subgroups of patients from trials of vitamin K antagonists vs. non-vitamin K oral anticoagulants (NOACs) for stroke prevention in AF with the aim to identify patient groups who might benefit from a particular OAC more than from another. In addition, we discuss the timing of initiation of anticoagulation. In the second of a two-part review, we discuss the use of NOAC for stroke prevention in the following subgroups of patients with AF: (vii) secondary stroke prevention in patients after stroke or transient ischaemic attack (TIA), (viii) patients with acute stroke requiring thrombolysis or thrombectomy, (ix) those initiating or restarting OAC treatment after stroke or TIA, (x) those with renal impairment on dialysis, (xi) the elderly, (xii) those at high risk of gastrointestinal bleeding, and (xiii) those with hypertension. In addition, we discuss adherence and compliance. Finally, we present a summary of treatment suggestions. In specific subgroups of patients with AF, evidence supports the use of particular NOACs and/or particular doses of anticoagulant. The appropriate choice of treatment for these subgroups will help to promote optimal clinical outcomes.

Point-of-care versus central laboratory testing of INR in acute stroke

OBJECTIVES

Effective anticoagulant therapy is a contraindication to thrombolysis, which is an effective treatment of ischemic stroke if given within 4.5 hours of symptom onset. INR above 1.7 is generally considered a contraindication for thrombolysis. Rapid measurement of INR in warfarin-treated patients is therefore of major importance in order to be able to decide on thrombolysis or not. We asked whether INR measured on a point-of-care instrument would be as good as a central laboratory instrument.

MATERIAL AND METHODS

A total of 529 consecutive patients who arrived at the emergency department at a large urban teaching hospital with stroke symptoms were enrolled in the study. INR was measured with a CoaguChek and a Sysmex instrument. Basic clinical information such as age, sex, and diagnosis (if available) was recorded. INR from the instruments was compared using linear regression and Bland-Altman plot.

RESULTS

Of 529 patients, 459 had INR results from both instruments. Among these, 3 patients were excluded as outliers. The rest (n = 456) showed good correlation between the methods (R²  = 0.97). In the current setting, CoaguChek was in median 63 minutes faster than Sysmex.

CONCLUSION

Our results indicate that point-of-care testing is a safe mean to rapidly acquire a patient's INR value in acute clinical situations.

European Academy of Neurology and European Stroke Organization consensus statement and practical guidance for pre-hospital management of stroke

BACKGROUND AND PURPOSE

The reduction of delay between onset and hospital arrival and adequate pre-hospital care of persons with acute stroke are important for improving the chances of a favourable outcome. The objective is to recommend evidence-based practices for the management of patients with suspected stroke in the pre-hospital setting.

METHODS

The GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology was used to define the key clinical questions. An expert panel then reviewed the literature, established the quality of the evidence, and made recommendations.

RESULTS

Despite very low quality of evidence educational campaigns to increase the awareness of immediately calling emergency medical services are strongly recommended. Moderate quality evidence was found to support strong recommendations for the training of emergency medical personnel in recognizing the symptoms of a stroke and in implementation of a pre-hospital 'code stroke' including highest priority dispatch, pre-hospital notification and rapid transfer to the closest 'stroke-ready' centre. Insufficient evidence was found to recommend a pre-hospital stroke scale to predict large vessel occlusion. Despite the very low quality of evidence, restoring normoxia in patients with hypoxia is recommended, and blood pressure lowering drugs and treating hyperglycaemia with insulin should be avoided. There is insufficient evidence to recommend the routine use of mobile stroke units delivering intravenous thrombolysis at the scene. Because only feasibility studies have been reported, no recommendations can be provided for pre-hospital telemedicine during ambulance transport.

CONCLUSIONS

These guidelines inform on the contemporary approach to patients with suspected stroke in the pre-hospital setting. Further studies, preferably randomized controlled trials, are required to examine the impact of particular interventions on quality parameters and outcome.

Thrombolysis in stroke patients: Comparability of point-of-care versus central laboratory international normalized ratio

BACKGROUND

In acute stroke patients, thrombolysis is one gold standard therapy option within the first four hours after the ischemic event. A contraindication for thrombolysis is an International Normalized Ratio (INR) value >1.7. Since time is brain, rapid and reliable INR results are fundamental. Aim was to compare INR values determined by central laboratory (CL) analyzer and Point-of-Care Testing(POCT)-device and to evaluate the quality of POCT performance in cases of potential therapeutic thrombolysis at a certified stroke unit.

METHODS

In 153 patients INR measurements using POCT-devices (HEMOCHRON Signature Elite®) were compared to INR measurements (BCS®XP) performed at the central laboratory. Outlier evaluation was performed regarding the critical thrombolysis cut-off.

RESULTS

Overall, we demonstrated a significant correlation (r = 0.809, p<0.0001) between both measurement methods. Mean value of the absolute difference between CL-INR and POCT-INR measurements was 0.23. In 95.4% of these cases, no differences regarding the critical cut-off (INR 1.7) were observed. POCT-INR values tended to be higher than the CL-INR values (p = 0.01). In 4.6% cases, a different value regarding thrombolysis cut-off was found. All patients were >75 years.

CONCLUSIONS

POCT-INR measurements based on our POCT concept are suitable to determine INR values in critical stroke patients. Nevertheless, outlier evaluation is mandatory.

Management of acute stroke in patients on oral anticoagulants

PURPOSE OF REVIEW

An increasing number of patients are receiving oral anticoagulants. Since non-vitamin K antagonist oral anticoagulants (NOACs) were approved, primary prevention of ischemic stroke has become simpler. However, managing ischemic stroke and intracerebral hemorrhage while on oral anticoagulation (OAC) has become more complex. This review covers the latest developments in managing ischemic and hemorrhagic stroke in patients receiving vitamin K antagonists (VKA) and NOACs.

RECENT FINDINGS

Testing coagulation in patients with acute ischemic stroke and receiving NOACs is complex, and observational data challenge guideline recommendations. Initial registry and cohort data support the safety of endovascular therapy despite OAC. In intracerebral hemorrhage, rapid reversal of VKA can be achieved better with prothrombin complex concentrates than with fresh frozen plasma. Furthermore, rapid reversal seems to be associated with less hematoma expansion and better functional outcome. In addition, new evidence strongly supports resuming OAC after intracerebral hemorrhage. The unfavorable properties of NOAC-related intracerebral hemorrhage are similar to those associated with VKA.

SUMMARY

Translation of recent findings might improve both outcome in acute ischemic and hemorrhagic stroke in patients on oral anticoagulants and help refine clinical management. Data from randomized clinical trials are scarce.

[Appropriate treatment of acute stroke at all times and in all places : Organizational concepts and new approaches]

Stroke is one of the most common neurological diseases in acute care. The introduction of new organizational concepts in the rescue chain and in acute inpatient services can significantly reduce time to treatment and patients can receive specific therapeutic options that have been shown to improve acute stroke prognosis. This review provides an overview of organizational structures that lead to improved medical care and outlines the evidence-based therapeutic options. This is intended to give the reader a decision support on provision of specific treatment in acute ischemic stroke. The almost simultaneous proof of effectiveness of mechanical thrombectomy for targeted patient populations in five randomized trials has challenged the organization of stroke care. This provides a good example of how an optimized interplay within the rescue chain from emergency services via community hospitals to referral centers with intervention facilities can ensure access to this novel treatment for as many patients as possible. For the limited time span between onset of symptoms and start of treatment, creative but nevertheless well-standardized concepts have emerged that lead to measurable therapeutic success. It has become an urgent challenge to create sustainable regional infrastructures that allow access to appropriate treatment for all patients.

Point-of-Care-Testing in Acute Stroke Management: An Unmet Need Ripe for Technological Harvest

Stroke, the second highest leading cause of death, is caused by an abrupt interruption of blood to the brain. Supply of blood needs to be promptly restored to salvage brain tissues from irreversible neuronal death. Existing assessment of stroke patients is based largely on detailed clinical evaluation that is complemented by neuroimaging methods. However, emerging data point to the potential use of blood-derived biomarkers in aiding clinical decision-making especially in the diagnosis of ischemic stroke, triaging patients for acute reperfusion therapies, and in informing stroke mechanisms and prognosis. The demand for newer techniques to deliver individualized information on-site for incorporation into a time-sensitive work-flow has become greater. In this review, we examine the roles of a portable and easy to use point-of-care-test (POCT) in shortening the time-to-treatment, classifying stroke subtypes and improving patient's outcome. We first examine the conventional stroke management workflow, then highlight situations where a bedside biomarker assessment might aid clinical decision-making. A novel stroke POCT approach is presented, which combines the use of quantitative and multiplex POCT platforms for the detection of specific stroke biomarkers, as well as data-mining tools to drive analytical processes. Further work is needed in the development of POCTs to fulfill an unmet need in acute stroke management.

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

Background

Point-of-care testing (POCT) of coagulation has been proven to be of great value in accelerating emergency treatment. Specific POCT for direct oral anticoagulants (DOAC) is not available, but the effects of DOAC on established POCT have been described. We aimed to determine the diagnostic accuracy of Hemochron® Signature coagulation POCT to qualitatively rule out relevant concentrations of apixaban, rivaroxaban, and dabigatran in real-life patients.

Methods

We enrolled 68 patients receiving apixaban, rivaroxaban, or dabigatran and obtained blood samples at six pre-specified time points. Coagulation testing was performed using prothrombin time/international normalized ratio (PT/INR), activated partial thromboplastin time (aPTT), and activated clotting time (ACT+ and ACT-low range) POCT cards. For comparison, laboratory-based assays of diluted thrombin time (Hemoclot) and anti-Xa activity were conducted. DOAC concentrations were determined by liquid chromatography-tandem mass spectrometry.

Results

Four hundred and three samples were collected. POCT results of PT/INR and ACT+ correlated with both rivaroxaban and dabigatran concentrations. Insufficient correlation was found for apixaban. Rivaroxaban concentrations at <30 and <100 ng/mL were detected with >95% specificity at PT/INR POCT ≤1.0 and ≤1.1 and ACT+ POCT ≤120 and ≤130 s. Dabigatran concentrations at <30 and <50 ng/mL were detected with >95% specificity at PT/INR POCT ≤1.1 and ≤1.2 and ACT+ POCT ≤100 s.

Conclusions

Hemochron® Signature POCT can be a fast and reliable alternative for guiding emergency treatment during rivaroxaban and dabigatran therapy. It allows the rapid identification of a relevant fraction of patients that can be treated immediately without the need to await the results of much slower laboratory-based coagulation tests.

Trial registration

Unique identifier, NCT02371070. Retrospectively registered on 18 February 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-017-1619-z) contains supplementary material, which is available to authorized users.

Coagulation Testing in Acute Ischemic Stroke Patients Taking Non–Vitamin K Antagonist Oral Anticoagulants

Background and Purpose—

In patients who present with acute ischemic stroke while on treatment with non–vitamin K antagonist oral anticoagulants (NOACs), coagulation testing is necessary to confirm the eligibility for thrombolytic therapy. We evaluated the current use of coagulation testing in routine clinical practice in patients who were on NOAC treatment at the time of acute ischemic stroke.

Methods—

Prospective multicenter observational RASUNOA registry (Registry of Acute Stroke Under New Oral Anticoagulants; February 2012–2015). Results of locally performed nonspecific (international normalized ratio, activated partial thromboplastin time, and thrombin time) and specific (antifactor Xa tests, hemoclot assay) coagulation tests were documented. The implications of test results for thrombolysis decision-making were explored.

Results—

In the 290 patients enrolled, nonspecific coagulation tests were performed in ≥95% and specific coagulation tests in 26.9% of patients. Normal values of activated partial thromboplastin time and international normalized ratio did not reliably rule out peak drug levels at the time of the diagnostic tests (false-negative rates 11%–44% [95% confidence interval 1%–69%]). Twelve percent of patients apparently failed to take the prescribed NOAC prior to the acute event. Only 5.7% (9/159) of patients in the 4.5-hour time window received thrombolysis, and NOAC treatment was documented as main reason for not administering thrombolysis in 52.7% (79/150) of patients.

Conclusions—

NOAC treatment currently poses a significant barrier to thrombolysis in ischemic stroke. Because nonspecific coagulation test results within normal range have a high false-negative rate for detection of relevant drug concentrations, rapid drug-specific tests for thrombolysis decision-making should be established.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01850797.

Quality Improvement in Acute Ischemic Stroke Care in Taiwan: The Breakthrough Collaborative in Stroke

In the management of acute ischemic stroke, guideline adherence is often suboptimal, particularly for intravenous thrombolysis or anticoagulation for atrial fibrillation. We sought to improve stroke care quality via a collaborative model, the Breakthrough Series (BTS)-Stroke activity, in a nationwide, multi-center activity in Taiwan. A BTS Collaborative, a short-term learning system for a large number of multidisciplinary teams from hospitals, was applied to enhance acute ischemic stroke care quality. Twenty-four hospitals participated in and submitted data for this stroke quality improvement campaign in 2010–2011. Totally, 14 stroke quality measures, adopted from the Get With The Guideline (GWTG)-Stroke program, were used to evaluate the performance and outcome of the ischemic stroke patients. Data for a one-year period from 24 hospitals with 13,181 acute ischemic stroke patients were analyzed. In 14 hospitals, most stroke quality measures improved significantly during the BTS-activity compared with a pre-BTS-Stroke activity period (2006–08). The rate of intravenous thrombolysis increased from 1.2% to 4.6%, door-to-needle time ≤60 minutes improved from 7.1% to 50.8%, symptomatic hemorrhage after intravenous thrombolysis decreased from 11.0% to 5.6%, and anticoagulation therapy for atrial fibrillation increased from 32.1% to 64.1%. The yearly composite measures of five stroke quality measures revealed significant improvements from 2006 to 2011 (75% to 86.3%, p<0.001). The quarterly composite measures also improved significantly during the BTS-Stroke activity. In conclusion, a BTS collaborative model is associated with improved guideline adherence for patients with acute ischemic stroke. GWTG-Stroke recommendations can be successfully applied in countries besides the United States.

Measuring non-vitamin K antagonist oral anticoagulant levels: When is it appropriate and which methods should be used?

Background

Although the need for an emergency intervention may merit laboratory measurement of non-vitamin K antagonist oral anticoagulant (NOAC) concentration or anticoagulant activity, NOACs are not supposed to require routine monitoring due to their stable pharmacological profiles compared with warfarin.

Aims

To examine situations where NOAC measurement may be useful and to provide information about methodologies available to measure NOAC-related anticoagulation activity.

Summary of review

The routine coagulation tests, including prothrombin time, thrombin time, activated partial thromboplastin time, and international normalized ratio, have variable sensitivities to NOACs. Tests have been developed for use with specific NOACs, e.g. diluted thrombin time or chromogenic factor Xa assays. In emergency situations, such as severe bleeding, stroke, or a requirement for urgent surgery or procedures, there may be a need to assess anticoagulant activity to guide clinical decision making. In cases where neutralization of the anticoagulant effect is warranted, specific reversal agents are likely to become invaluable medical tools. Evidence to date suggests that dosing decisions for NOACs based on clinical features (e.g. age or renal function) can help optimize the benefit–risk balance without assessment of anticoagulant activity in non-emergency routine situations.

Conclusions

Regular monitoring of NOAC levels does not provide benefits and cannot be recommended at present. In some specific circumstances, e.g. severe bleeding, before urgent surgery, or before thrombolysis, measurement may be beneficial to assess whether a patient is actively anticoagulated. The availability of NOAC-specific reversal agents may change management practices in emergencies.

Effective management of patients with acute ischemic stroke based on lean production on thrombolytic flow optimization

The efficacy of thrombolytic therapy for acute ischemic stroke (AIS) decreases when the administration of tissue plasminogen activator (tPA) is delayed. Derived from Toyota Production System, lean production aims to create top-quality products with high-efficiency procedures, a concept that easily applies to emergency medicine. In this study, we aimed to determine whether applying lean principles to flow optimization could hasten the initiation of thrombolysis. A multidisciplinary team (Stroke Team) was organized to implement an ongoing, continuous loop of lean production that contained the following steps: decomposition, recognition, intervention, reengineering and assessment. The door-to-needle time (DNT) and the percentage of patients with DNT ≤ 60 min before and after the adoption of lean principles were used to evaluate the efficiency of our flow optimization. Thirteen patients with AIS in the pre-lean period and 43 patients with AIS in the lean period (23 in lean period I and 20 patients in lean period II) were consecutively enrolled in our study. After flow optimization, we reduced DNT from 90 to 47 min (p < 0.001^¤). In addition, the percentage of patients treated ≤60 min after hospital arrival increased from 38.46 to 75.0 % (p = 0.015^¤). Adjusted analysis of covariance confirmed a significant influence of optimization on delay of tPA administration (p < 0.001). The patients were more likely to have a good prognosis (mRS ≤ 2 at 90 days) after the flow optimization (30.77-75.00 %, p = 0.012^¤). Our study may offer an effective approach for optimizing the thrombolytic flow in the management of AIS.

Factors Associated with In-Hospital Delay in Intravenous Thrombolysis for Acute Ischemic Stroke: Lessons from China

In-hospital delay reduces the benefit of intravenous thrombolysis (IVT) in acute ischemic stroke (AIS), while factors affecting in-hospital delay are less well known in Chinese. We are aiming at determining the specific factors associated with in-hospital delay through a hospital based cohort. In-hospital delay was defined as door-to-needle time (DTN) ≥60min (standard delay criteria) or ≥75% percentile of all DTNs (severe delay criteria). Demographic data, time intervals [onset-to-door time (OTD), DTN, door-to-examination time (DTE), door-to-imaging time (DTI), door-to-laboratory time (DTL) and final-test-to-needle time (FTN, the time interval between the time obtaining the result of the last screening test and the needle time)], medical history and additional variables were calculated using Mann-Whitney U or Pearson Chi-Square tests for group comparison, and multivariate linear regression analysis was performed to identify independent variables of in-hospital delay. A total of 202 IVT cases were enrolled. The median age was 61 years and 25.2% were female. The cutoff points for the upper quartile of DTN (severe delay criteria) was 135min.When compared with the reference group without in-hospital delay, older age, shorter OTD and less referral were found in the standard delay group and male sex, presence with transient ischemic attacks or rapidly improving symptom, and with multi-model CT imaging were more frequent in the severe delay group. In the multivariate linear regression analysis, FTN (P<0.001) and DTL (P = 0.002) were significantly associated with standard delay; while DTE (P = 0.005), DTI (P = 0.033), DTL (P<0.001), and FTN (P<0.001) were positively associated with severe delay. There was not a significant change in the trend of DTNs during the study period (P = 0.054). In-hospital delay was due to multifactors in China, in which time delays of decision-making process and laboratory tests contributed the most. Efforts aiming at reducing the delay should be focused on the optimization for the items of screening tests and improvement of the pathway organization.

[From stroke to reperfusion : How can we be faster?]

BACKGROUND

During the last two decades major efforts in clinical research have led to the establishment of intravenous thrombolysis as the first line acute therapy for ischemic stroke. More recently, data from successful phase III trials have provided proof of the efficiency of mechanical recanalization in acute stroke. The fact that the efficiency of the available therapies can be increased through faster delivery is well documented; however, many institutions dealing with the emergency care of stroke patients lack organizational or infrastructural arrangements to optimize time efficiency in the diagnostic and therapeutic workup.

CONCLUSION

Many of these arrangements have been well evaluated, can be implemented at reasonable costs and have been proven to increase the beneficial effects of thrombolytic therapy.

Management of the Interventional Stroke Patient

OPINION STATEMENT

The acute treatment of major ischemic stroke has been revolutionized by strong and consistent evidence from multiple randomized trials. Endovascular treatment by mechanical thrombectomy will be increasingly chosen as an adjunctive or alternative to intravenous thrombolysis. To apply this form of stroke treatment is associated with the challenge of optimal periinterventional treatment. The patient has to be identified, counselled, prepared, monitored, cardiovascularly stabilized, possibly sedated and ventilated, and postprocedurally treated in the optimal way. However, most aspects of periinterventional treatment have as yet not been clarified and require prospective research. Among these, the question of general anesthesia vs conscious sedation has received most attention and may be the most crucial one. Based on a great amount of retrospective data, it appears reasonable to start the intervention under conscious sedation of the non-intubated patient with standby measures for emergent intubation, until prospective randomized trials have clarified that issue. Periinterventional management will significantly affect the success of recanalization.

Point-of-Care Testing of Coagulation in Patients Treated With Non-Vitamin K Antagonist Oral Anticoagulants

BACKGROUND AND PURPOSE

Specific coagulation assays for non-vitamin K antagonist oral anticoagulants (NOAC) are relatively slow and often lack availability. Although specific point-of-care tests (POCT) are currently not available, NOAC are known to affect established coagulation POCT. This study aimed at determining the diagnostic accuracy of the CoaguChek POCT to rule out relevant concentrations of rivaroxaban, apixaban, and dabigatran in real-life patients.

METHODS

We consecutively enrolled 60 ischemic stroke patients newly started on NOAC treatment and obtained blood samples at 6 prespecified time points. Samples were tested using the CoaguChek POCT, laboratory-based coagulation assays (prothrombin time and activated partial thromboplastin time, anti-Xa test and Hemoclot), and liquid chromatography-tandem mass spectrometry for direct determination of NOAC concentrations.

RESULTS

Three hundred fifty-six blood samples were collected. The CoaguChek POCT strongly correlated (r=0.82 P<0.001) with rivaroxaban concentrations but did not accurately detect dabigatran or apixaban. If used to estimate the presence of low rivaroxaban concentrations, POCT was superior to predictions based on normal prothrombin time and activated partial thromboplastin time values even if sensitive reagents were used. POCT-results≤1.0 predicted rivaroxaban concentrations<32 and <100 ng/mL with a specificity of 90% and 96%, respectively.

CONCLUSIONS

If anti-Xa test is not available, we propose the use of the CoaguChek POCT to guide thrombolysis decisions after individual risk assessment in rivaroxaban-treated patients having acute ischemic stroke.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02371044.

Point of care coagulometry in prehospital emergency care: an observational study

Background

Haemostatic impairment can have a crucial impact on the outcome of emergency patients, especially in cases of concomitant antithrombotic drug treatment. In this prospective observational study we used a point of care (POC) coagulometer in a prehospital physician-based emergency medical system in order to test its validity and potential value in the treatment of emergency patients.

Methods

During a study period of 12 months, patients could be included if venous access was mandatory for further treatment. The POC device CoaguChek® was used to assess international normalized ratio (INR) after ambulance arrival at the scene. Results were compared with in-hospital central laboratory assessment of INR. The gain of time was analysed as well as the potential value of POC testing through a questionnaire completed by the responsible prehospital emergency physician.

Results

A total of 103 patients were included in this study. POC INR results were highly correlated with results of conventional assessment of INR (Bland-Altman-bias: 0.014). Using a cutoff value of INR >1.3, the device’s sensitivity to detect coagulopathy was 100 % with a specificity of 98.7 %. The median gain of time was 69 min. Treating emergency physicians considered the value of prehospital POC INR testing ‘high’ in 9 % and ‘medium’ in 21 % of all patients. In patients with tracer diagnosis ‘neurology’, the value of prehospital INR assessment was considered ‘high’ or ‘medium’ (63 %) significantly more often than in patients with non-neurological tracer diagnoses (24 %).

Conclusions

Assessment of INR through a POC coagulometer is feasible in prehospital emergency care and provides valuable information on haemostatic parameters in patients. Questionnaire results suggest that POC INR testing may present a valuable technique in selected patients. Whether this information translates into an improved management of respective patients has to be evaluated in further studies.

Is point-of-care accurate for indicating thrombolysis in anticoagulated patients on oral anticoagulation treatments?

The use of oral anticoagulation treatment (OAT) in patients with an international normalized ratio (INR) higher than 1.7 is a contraindication to thrombolysis in acute ischemic stroke. The aim of the present study is to compare the use of point-of-care (POC) coagulometers to the standard coagulation analysis (SCA) procedure of the INR as a decision-making test for use with patients taking OAT.

METHOD

Eighty patients on chronic OAT underwent a POC and an SCA during a regular outpatient evaluation.

RESULTS

When comparing the abilities of the POC test and the SCA test to identify adequate levels for thrombolysis (≤1.7), the POC had a sensitivity of 96.6% (95%CI 88.4-99.1) and a specificity of 60.0% (95%CI 38.6-78). POC overestimated INR levels by 0.51 points compared to the SCA test.

CONCLUSION

POC has a high sensitivity compared to the SCA test for the identification of patients within the cut-off point for thrombolysis.

Point of care coagulation testing in neurosurgery

Impaired haemostasis represents a major risk factor for bleeding complications in neurosurgical patients. Coagulopathy commonly occurs after (brain) trauma and major haemorrhage or originates from antithrombotic medication. Point of care (POC) devices for bedside assessment of haemostatic parameters are increasingly used in various medical specialties. Results can be instantly implemented into treatment modalities as results are delivered within a very short period. POC coagulation testing has also shown beneficial effects in the treatment of neurosurgical patients. Identification of hyperfibrinolysis is achieved through viscoelastic testing of haemostasis and bedside coagulometry hastens the management of anticoagulated patients in need of urgent neurosurgical procedures. Results of POC testing of platelet function have been correlated with patient outcomes after traumatic brain injury and furthermore, quantification of antiplatelet medication effects on platelet activity is made possible through the use of these devices. Further studies are needed to characterise the potential of POC testing of platelet function. Antiplatelet medication plays an important role in regard to haemorrhagic and thromboembolic risks. Therefore, POC testing of platelet activity may improve treatment modalities in patients undergoing neurosurgical procedures as well as neurointerventional procedures (such as intracranial stent placement). In this article we summarise the available data of POC testing in neurosurgical patients and discuss the potential of these devices in this field. POC technologies have improved patient care in various medical fields and in our view it is likely that this will also apply to the field of neurosurgery.

Assessment of point-of-care measurement of international normalised ratio using the CoaguChek XS Plus system in the setting of acute ischaemic stroke

BACKGROUND AND AIMS

Thrombolysis with alteplase (recombinant tissue plasminogen activator) is accepted hyperacute therapy for acute ischaemic stroke. Clotting must be normal before this can be administered safely. Laboratory testing of international normalised ratio (INR) takes 30-60 min, which can significantly delay administration of recombinant tissue plasminogen activator. Previous studies have suggested that point-of-care testing is useful in patients presenting with stroke and improves door-to-needle time. We performed a prospective study of point-of-care testing in patients presenting with acute ischaemic stroke.

METHODS

Fifty patients were entered into the study to compare point-of-care testing using the CoaguChek XS system with laboratory testing of INR.

RESULTS

Point-of-care testing correlated well with laboratory levels (R = 0.93, P < 0.0001). The standard deviation of difference between the two was 0.115. Overall, point-of-care testing tended to underestimate INR slightly, meaning that an INR value of 1.1 or less was required to be 95% certain that the laboratory value was 1.3 or below. Simultaneous testing using blood from a syringe was more consistent with laboratory results than testing capillary blood through finger prick.

CONCLUSION

Point-of-care INR testing correlates well with laboratory values. The results in this study mostly relate to values in the normal range. We suggest that it can be used to try to shorten door-to-needle time.

Minimising time to treatment: targeted strategies to minimise time to thrombolysis for acute ischaemic stroke

Time to thrombolysis is a critical determinant of favourable outcomes in acute ischaemic stroke. It is not infrequent that patient outcomes are compromised due to out-of-hospital and in-hospital time delays. On the other hand, time delays could be minimised through the identification of barriers and the implementation of targeted solutions. This review outlines the different strategies in minimising treatment delays and offers recommendations. Literature search in PubMed, Medline and EBSCO Host was conducted to identify studies that are relevant to reduction of time to treatment from January 1995 to December 2012. Strategies to reduce time to thrombolysis are categorised into pre-hospital strategies, in-hospital strategies and post-treatment decision strategies. Proposed pre-hospital strategies include public education on stroke symptoms awareness, prioritising stroke by emergency medical services, increasing ease of access to medical records, pre-hospital notification, and mobile computed tomography scanning. In-hospital strategies include a streamlined code stroke system, computed tomography scanner co-location with emergency department, 24/7 availability of stroke physicians, point-of-care laboratory testing and access to expert neuroimaging interpretation. Post-decision strategies include increasing availability of intravenous thrombolysis and simplification of informed consent procurement. Time to thrombolysis delays is multifactorial. Effective reduction of time delays for acute ischaemic stroke requires the correct identification of and targeted strategies to overcome time barriers.

Stroke code improves intravenous thrombolysis administration in acute ischemic stroke

Background and Purpose

Timely intravenous (IV) thrombolysis for acute ischemic stroke is associated with better clinical outcomes. Acute stroke care implemented with “Stroke Code” (SC) may increase IV tissue plasminogen activator (tPA) administration. The present study aimed to investigate the impact of SC on thrombolysis.

Methods

The study period was divided into the “pre-SC era” (January 2006 to July 2010) and “SC era” (August 2010 to July 2013). Demographics, critical times (stroke symptom onset, presentation to the emergency department, neuroimaging, thrombolysis), stroke severity, and clinical outcomes were recorded and compared between the two eras.

Results

During the study period, 5957 patients with acute ischemic stroke were admitted; of these, 1301 (21.8%) arrived at the emergency department within 3 h of stroke onset and 307 (5.2%) received IV-tPA. The number and frequency of IV-tPA treatments for patients with an onset-to-door time of <3 h increased from the pre-SC era (n = 91, 13.9%) to the SC era (n = 216, 33.3%) (P<0.001). SC also improved the efficiency of IV-tPA administration; the median door-to-needle time decreased (88 to 51 min, P<0.001) and the percentage of door-to-needle times ≤60 min increased (14.3% to 71.3%, P<0.001). The SC era group tended to have more patients with good outcome (modified Rankin Scale ≤2) at discharge (49.5 vs. 39.6%, P = 0.11), with no difference in symptomatic hemorrhage events or in-hospital mortality.

Conclusion

The SC protocol increases the percentage of acute ischemic stroke patients receiving IV-tPA and decreases door-to-needle time.

Rivaroxaban does not increase hemorrhage after thrombolysis in experimental ischemic stroke

The management of acute ischemic stroke during anticoagulation with a novel oral anticoagulant (NOAC) is challenging because intravenous thrombolysis is contraindicated because of a putative increased risk of intracerebral hemorrhagic complications. We examined the risk of secondary postischemic hemorrhage after thrombolysis in rodents pretreated with rivaroxaban or warfarin. Mice were pretreated with either rivaroxaban (30 mg/kg), warfarin (target international normalized ratio 2 to 3) or vehicle. After 2 or 3 hours, middle cerebral artery occlusion (MCAO), mice received 9 mg/kg recombinant tissue plasminogen activator. Twenty-four hours after MCAO, secondary hemorrhage was quantified using a macroscopic hemorrhage score and hemoglobin spectrophotometry. Blood-brain barrier (BBB) permeability was measured by Evans Blue spectrofluorometry. To increase the validity of our findings, experiments were also performed using a thromboembolic model in anticoagulated rats. Infarct size did not differ among groups. Pretreatment with warfarin led to significantly more secondary hemorrhage compared with rivaroxaban and nonanticoagulated controls after 2- and 3-hour ischemia in mice as well as in rats. Blood-brain barrier permeability was significantly higher in the warfarin group compared with rivaroxaban and control. Thus, rivaroxaban in contrast to warfarin does not increase secondary hemorrhage after thrombolysis in experimental cerebral ischemia. Less effects of rivaroxaban on postischemic BBB permeability may account for this difference.

Differences in process management and in-hospital delays in treatment with iv thrombolysis

OBJECTIVES

Rapid initiation of intravenous thrombolysis improves patient's outcome in acute stroke. We analyzed inter-center variability and factors that influence the door-to-needle time with a special focus on process measurements in all Austrian stroke units.

METHODS

Case level data of patients receiving intravenous thrombolysis in the Austrian Stroke Unit Registry were enriched with information of a structured questionnaire on center specific process measures of all Austrian stroke units. Influence of case and center specific variables was determined by LASSO procedure.

RESULTS

Center specific median door-to-needle time ranged between 30 and 78 minutes. Between April 2004 and November 2012, 6246 of 57991 patients treated in Austrian stroke units with acute ischemic stroke received intravenous thrombolysis. An onset-to-door time >120 minutes, patients with total anterior circulation stroke, recent year of admission, patient transportation with ambulance crew and emergency physician, the use of point of care tests reduced the door-to-needle time, whereas onset-to-door ≤ 60 minutes, unknown onset-to-door, patients with an NIHSS ≤ 4 or posterior circulation stroke, initial admission to a general emergency department, a distant radiology department, primary imaging modality other than plain CT and waiting for the lab results were associated with an increase in door-to-needle time. Case level and center specific factors could explain the inter center variability of door-to-needle times in 31 of 34 stroke units in Austria.

CONCLUSIONS

In light of our results it seems crucial that every single stroke center documents and critically reviews possibilities of optimizing practice strategies in acute stroke care.

Recommendations for the emergency management of complications associated with the new direct oral anticoagulants (DOACs), apixaban, dabigatran and rivaroxaban

Dabigatran, apixaban, and rivaroxaban have been approved for primary and secondary stroke prevention in patients with atrial fibrillation. However, questions have arisen about how to manage emergency situations, such as when thrombolysis would be required for acute ischemic stroke or for the managing intracranial or gastrointestinal bleedings. We summarize the current literature and provide recommendations for the management of these situations. Peak plasma levels of the direct oral anticoagulants (DOACs) apixaban, dabigatran, or rivaroxaban are observed about 2-4 h after intake. Elimination of dabigatran is mainly dependent on renal function. Consequently, if renal function is impaired, there is a risk of drug accumulation that is highest for dabigatran followed by rivaroxaban and then apixaban and thus dosing recommendations are different. To date, no bedside tests are available that reliably assess the anticoagulatory effect of DOACs, nor are specific antidotes available. We recommend performing the following tests if DOAC intake is unknown: dabigatran-associated bleeding risk is minimized or can be neglected if thrombin time, Hemoclot test, or Ecarin clotting time is normal. Apixaban and rivaroxaban effects can be ruled out if findings from the anti-factor Xa activity test are normal. High plasma levels of DOAC are also mostly excluded if PTT and PTZ are normal four or more hours after DOAC intake. However, normal values of global coagulation tests are not sufficient if thrombolysis is indicated for treating acute stroke. The decision for or against thrombolysis is an individual decision; in these cases, thrombolysis use is off-label. In case of bleeding, prothrombin complex concentrates seems to be the most plausible treatment. For severe gastrointestinal bleeding with life-threatening blood loss, the bleeding source needs to be identified and treated by invasive measures. Use of procoagulant drugs (antifibrinolytics) might also be considered. However, there is very limited clinical experience with these products in conjunction with DOAC.

Potential blood biomarkers for stroke

Stroke is one of the most common causes of death worldwide and a major cause of acquired disability in adults. Despite advances in research during the last decade, prevention and treatment strategies still suffer from significant limitations, and therefore new theoretical and technical approaches are required. Technological advances in the proteomic and metabolomic areas, during recent years, have permitted a more effective search for novel biomarkers and therapeutic targets that may allow for effective risk stratification and early diagnosis with subsequent rapid treatment. This review provides a comprehensive overview of the latest candidate proteins and metabolites proposed as new potential biomarkers in stroke.

Oral anticoagulants--a frequent challenge for the emergency management of acute ischemic stroke

BACKGROUND

The emergency management of patients with acute ischemic stroke (IS) using oral anticoagulants (OAC) represents a great challenge. Effective anticoagulation predisposes to bleeding and represents a contraindication for systemic thrombolysis. However, patients on OAC can receive intravenous thrombolysis with recombinant tissue-type plasminogen activator if the international normalized ratio (INR) does not exceed 1.7, but data regarding the risk of hemorrhagic complications are highly controversial. Neurointerventional recanalization of intracranial artery occlusion represents an alternative option in OAC patients with acute IS. The proportion of OAC users among consecutive patients who suffer from acute IS or transient ichemic attacks (TIA) is unknown.

METHODS

A prospective observational study, consecutively enrolling all patients with IS or TIA admitted to our neurological emergency room (ER), was performed between August 2009 and February 2011. Basic demographic variables, present use of OAC, severity of stroke, cardiovascular risk factors, INR values and the symptom onset to presentation time were recorded. In IS patients on OAC presenting within 4.5 h after symptom onset, management was analyzed. In thrombolysed IS patients, bleeding events were documented. Outcome was assessed after 3 months.

RESULTS

During the study period, 12,237 patients were admitted to our neurological ER. IS or TIA were diagnosed in 2,074 (16.9%). Complete data were available for 1,914 of these subjects (92.3%); 53.8% were male (median age: 72 years). 69.7% suffered IS, 30.3% TIA. OAC were being used by 8.7% of all patients. OAC patients were older than non-OAC patients (78 vs. 72 years, p < 0.001). Subtherapeutic INR values (<2.0) were found in 67.3% of OAC patients with IS. 54.8% of all OAC IS patients presented at the ER within ≤4.5 h after the event (57/104). An INR ≤1.7 - compatible with systemic thrombolysis - was present in 33/57 patients (57.9%). Recanalization therapy was performed in 21/57 patients (36.8%). No difference in symptomatic or fatal intracerebral bleedings between thrombolysed patients with and without prior OAC use was observed (p = 0.720 and 0.135, respectively). Multivariable analysis of predictors of the 3-month outcome in IS patients revealed that prior medication with OAC was neither associated with an unfavorable clinical outcome after 3 months in the whole population of stroke patients (p = 0.235) nor in patients in whom recanalization approaches were used (n = 306; p = 0.271).

CONCLUSIONS

Oral anticoagulation represents a frequent challenge for the emergency manangement of IS. A considerable proportion of anticoagulated IS patients appears to be eligible for thrombolysis. Establishing standardized treatment procedures in these patients is warranted.

POINT-OF-CARE HEMATOLOGY AND COAGULATION TESTING IN PRIMARY, RURAL EMERGENCY, AND DISASTER CARE SCENARIOS

The purpose of this article is to review current principles and criteria for obtaining Clinical Laboratory Improvement Amendments of 1988 (CLIA '88) waiver, identify existing point-of-care (POC) coagulation and hematology technologies, and analyze regulatory challenges regarding CLIA-waiver for those and future devices. CLIA '88 documentation requires tests performed by laboratories with a Certificate of Waiver to be so simple that the likelihood of erroneous results by the user is negligible, or poses no unreasonable risk of harm to the patient if performed incorrectly as determined by the Secretary of Health and Human Services. "Simple" means that the test uses unprocessed samples, has a direct read-out of test results, does not have specifications for user training, and includes instructions for confirmatory testing when advisable. Currently the CLIA-waived hematology and coagulation POC devices only test for hemoglobin (Hb), hematocrit (Hct), and prothrombin time/international normalized ratio (PT/INR). The problem with these devices is the lack of multiplexing. POC coagulation and hematology devices face challenges for obtaining a waiver. These challenges include the lack of clinical needs assessment, miniturized assays that correct for interfering substances, and assays simple enough to be combined in a multiplex platform. Several scenarios demonstrate how POC coagulation or hematology devices can improve crisis care. Industry should perform needs assessment on clinicians and emergency responders to determine which analytes to incorporate on multiplex POC coagulation and hematology devices, and produce devices that address confounding factors.