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

Safety of recanalization therapy in patients with acute ischemic stroke on direct oral anticoagulants: A sub-analysis of PASTA registry study

BACKGROUND

The safety of intravenous recombinant tissue plasminogen activator (rtPA) and mechanical thrombectomy (MT) in patients treated with direct oral anticoagulants (DOACs) before stroke has not been fully investigated. Therefore, we aimed to investigate the safety of recanalization therapy in patients receiving DOACs.

METHODS

We assessed data from a prospective multicenter registry of patients with stroke, including those with acute ischemic stroke (AIS) treated with rtPA and/or MT who were administered DOACs. We evaluated the safety of recanalization considering the DOACs dosage and interval between the last DOAC intake and recanalization.

RESULTS

The final analysis included 108 patients (women, n = 54; median age, 81 years; DOAC overdose, n = 7; appropriate dose, n = 74; and inappropriate low dose, n = 27). The rate of any ICH differed significantly among overdose-, appropriate dose-, and inappropriate-low dose DOACs groups (71.4, 23.0, and 33.3%, respectively; P = 0.0121), whereas no significant difference was observed in respect of symptomatic ICH (P = 0.6895). Multivariate analysis showed that the National Institutes of Health Stroke Scale score on admission (odds ratio [OR]: 1.06, 95% confidence interval [CI]: 1.01-1.11; P = 0.0267) and overdose-DOAC (OR: 8.40, 95% CI: 1.24-56.88; P = 0.0291) were independently associated with any ICH. No relationship was observed between the timing of the last DOAC intake and occurrence of ICH in patients treated with rtPA and/or MT (all P > 0.05).

CONCLUSION

Recanalization therapy during DOAC treatment may be safe in selected patients with AIS, if it is performed >4 h after the last DOAC intake and the patient is not overdosed with DOACs.

REGISTRATION

https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000034958.

Failure of Therapeutic Anticoagulation in COVID-19 Patients With Acute Ischemic Stroke. A Retrospective Multicenter Study

Background

Acute ischemic stroke (AIS) is a possible complication of coronavirus disease 2019 (COVID-19) infection. Although peculiar clinical features and underlying specific mechanisms of thrombogenesis have been suggested so far, there is no consensus on the appropriate vascular preventive drug regimen in patients with COVID-19.

Aim and Methods

From a larger clinical series of consecutive acute ischemic strokes related to COVID-19 admitted to three cerebrovascular units in Northern Italy, herein, we describe the clinical features of a subgroup of patients in whom stroke occurred despite therapeutic anticoagulation.

Results

A total of seventeen/80 AIS related to COVID-19 (21.2%) occurred in anticoagulated patients. Although no blood level was available for Direct Oral AntiCoagulant, the drug dosage was appropriate according to guidelines. Their National Institute of Health Stroke Scale (NIHSS) at admission was 12.0 (SD = 7.4) and 58.8% of them had evidence of large vessel occlusion. The case fatality rate was as high as 64.7%.

Discussion and Conclusions

The occurrence of an anticoagulation failure seems to be increased in the setting of COVID-19 infection, with worse clinical outcomes if compared to non-COVID-19 related ischemic strokes. We discuss the diagnostic and therapeutic implications of such evidence, suggesting that some arterial thrombotic complications might be either resistant to or independent of the anticoagulation effect.

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.

Management of stroke in patients on antithrombotic therapy: Practical issues in the era of direct oral anticoagulants

Antithrombotic drugs (ADs) are the mainstay of secondary prevention of thrombotic vascular diseases. Management of patients under long-term treatment with ADs admitted for acute cerebrovascular disease, either ischemic stroke (IS) or intracerebral hemorrhage (ICH), has become a frequent situation that might influence decision-making processes from diagnosis to therapeutic strategies. The aim of this review is to summarize current data from the literature to help clinicians in their decisions for stroke care in patients taking ADs. While a large body of data have made it possible to codify the management of patients presenting IS or ICH under antiplatelet drugs and vitamin K antagonists, the increasing use of direct oral anticoagulants (DOAs) and future development of new antiplatelet drugs raise new problems. Development of rapid assessment tools measuring specific biological activity and reversion agents dedicated to each class of DOAs should make it possible to optimize individual therapeutic strategies. This review highlights the main steps of IS and ICH management from early identification of ADs, and use of dedicated biological assays, to the stepwise strategy to apply revascularization or reversal therapies and finally the resumption of ADs with a focus on individual clinical and radiological characteristics for more personalized care.

Prior Anticoagulation in Patients with Ischemic Stroke and Atrial Fibrillation

OBJECTIVE

The aim was to evaluate, in patients with atrial fibrillation (AF) and acute ischemic stroke, the association of prior anticoagulation with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs) with stroke severity, utilization of intravenous thrombolysis (IVT), safety of IVT, and 3-month outcomes.

METHODS

This was a cohort study of consecutive patients (2014-2019) on anticoagulation versus those without (controls) with regard to stroke severity, rates of IVT/mechanical thrombectomy, symptomatic intracranial hemorrhage (sICH), and favorable outcome (modified Rankin Scale score 0-2) at 3 months.

RESULTS

Of 8,179 patients (mean [SD] age, 79.8 [9.6] years; 49% women), 1,486 (18%) were on VKA treatment, 1,634 (20%) on DOAC treatment at stroke onset, and 5,059 controls. Stroke severity was lower in patients on DOACs (median National Institutes of Health Stroke Scale 4, [interquartile range 2-11]) compared with VKA (6, [2-14]) and controls (7, [3-15], p < 0.001; quantile regression: β -2.1, 95% confidence interval [CI] -2.6 to -1.7). The IVT rate in potentially eligible patients was significantly lower in patients on VKA (156 of 247 [63%]; adjusted odds ratio [aOR] 0.67; 95% CI 0.50-0.90) and particularly in patients on DOACs (69 of 464 [15%]; aOR 0.06; 95% CI 0.05-0.08) compared with controls (1,544 of 2,504 [74%]). sICH after IVT occurred in 3.6% (2.6-4.7%) of controls, 9 of 195 (4.6%; 1.9-9.2%; aOR 0.93; 95% CI 0.46-1.90) patients on VKA and 2 of 65 (3.1%; 0.4-10.8%, aOR 0.56; 95% CI 0.28-1.12) of those on DOACs. After adjustments for prognostic confounders, DOAC pretreatment was associated with a favorable 3-month outcome (aOR 1.24; 1.01-1.51).

INTERPRETATION

Prior DOAC therapy in patients with AF was associated with decreased admission stroke severity at onset and a remarkably low rate of IVT. Overall, patients on DOAC might have better functional outcome at 3 months. Further research is needed to overcome potential restrictions for IVT in patients taking DOACs. ANN NEUROL 2021;89:42-53.

MT in anticoagulated patients

Mechanical thrombectomy (MT) is one of the main treatments for acute ischemic stroke (AIS) in patients on effective anticoagulation. The use of direct oral anticoagulants (DOA) has increased, given their efficacy and safety profile compared to vitamin K antagonists (VKA). We compared procedural and clinical outcomes of MT in patients on DOA and VKA treatment before stroke onset. We analyzed 2 groups from the Endovascular Treatment in Ischemic Stroke prospective registry: patients on DOA and patients on VKA treated by MT without thrombolysis. Generalized linear mixed models including center as random effect were used to compare angiographic (rates of reperfusion at end of procedure, number of passes >2, procedural complications) and clinical (favorable and excellent outcome, 90-day all-cause mortality, and hemorrhagic complications) outcomes according to anticoagulation subgroups. Comparisons were adjusted for prespecified confounders (age, admission NIH Stroke Scale score) as well as for meaningful baseline between-group differences. Among 221 patients included, more DOA-treated patients (n = 115, 52%) achieved successful (modified Thrombolysis in Cerebral Infarction score [mTICI] 2b/3) or near complete (mTICI 2c/3) reperfusion at the procedure end than did VKA-treated patients, with an adjusted odds ratio (OR) for DOA vs VKA of 3.27 (95% confidence interval [CI], 1.40–7.65) and 2.00 (95% CI, 1.08–3.73), respectively. DOA-treated patients had a lower 90-day mortality risk with an adjusted OR of 0.47 (95% CI, 0.24–0.89) and a better excellent outcome OR of 2.40 (1.10–5.27). There was no significant between-group difference in hemorrhagic or procedural complications. The study highlights the benefits of DOA compared to VKA. Regarding mortality, excellent outcomes, and recanalization rate, DOA appears to provide a favorable setting for MT treatment in AIS.

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.

Microfluidic coagulation assay for monitoring anticoagulant therapy in acute stroke patients

Reliable detection of anticoagulation status in patients treated with non-vitamin K antagonist oral anticoagulants (NOACs) is challenging but of importance especially in the emergency setting. This study evaluated the potential of a whole-blood clotting time assay based on Surface Acoustic Waves (SAW-CT) in stroke-patients. The SAW-technology was used for quick and homogenous recalcification of whole blood inducing a surface-activated clotting reaction quantified and visualised by real-time fluorescence microscopy with automatic imaging processing. In 20 stroke or transient ischaemic attack (TIA)-patients taking NOACs kinetics of SAW-CT were assessed and correlated to other coagulation parameters (PT, aPTT) and NOAC-plasma concentration measured by tandem mass spectrometry (LC-MS/MS). In 225 emergency patients with suspicion of acute stroke or TIA, SAW-CT values were assessed. Mean (± SD) SAW-CT in non-anticoagulated stroke patients (n=180) was 124 s (± 21). In patients on dabigatran or rivaroxaban, SAW-CT values were significantly higher 2 and 8 hours (h) after intake rising up to 267 seconds (s) (dabigatran, 2 h after intake) and 250 s (rivaroxaban, 8 h after intake). In patients on apixaban, SAW-CT values were only moderately increased 2 h after intake (SAW-CT 153 s). In emergency patients, SAW-CT values were significantly higher in NOAC and vitamin K antagonist (VKA)-treated as compared to non-anticoagulated patients. In conclusion, the SAW-CT assay is capable to monitor anticoagulant level and effect in patients receiving dabigatran, rivaroxaban and the VKA phenprocoumon. It has a limited sensitivity for apixaban-detection. If specific SAW-CT results were used as cut-offs, SAW-CT yields high diagnostic accuracy to exclude relevant rivaroxaban and dabigatran concentrations in stroke-patients.

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.

Safety of intra-arterial treatment in acute ischaemic stroke patients on oral anticoagulants. A cohort study and systematic review

BACKGROUND AND PURPOSE

An elevated international normalized ratio (INR) of >1.7 is a contraindication for the use of intravenous thrombolytics in acute ischaemic stroke. Local intra-arterial therapy (IAT) is considered a safe alternative. The safety and outcome of IAT were investigated in patients with acute ischaemic stroke using oral anticoagulants (OACs).

METHODS

Data were obtained from a large national Dutch database on IAT in acute stroke patients. Patients were categorized according to the INR: >1.7 and ≤1.7. Primary outcome was symptomatic intracerebral hemorrhage (sICH), defined as deterioration in the National Institutes of Health Stroke Scale score of ≥4 and ICH on brain imaging. Secondary outcomes were clinical outcome at discharge and 3 months. Occurrence of outcomes was compared with risk ratios and corresponding 95% confidence intervals. Further, a systematic review and meta-analysis on sICH risk in acute stroke patients on OACs treated with IAT was performed.

RESULTS

Four hundred and fifty-six patients were included. Eighteen patients had an INR > 1.7 with a median INR of 2.4 (range 1.8-4.1). One patient (6%) in the INR > 1.7 group developed a sICH compared with 53 patients (12%) in the INR ≤ 1.7 group (risk ratio 0.49, 95% confidence interval 0.07-3.13). Clinical outcomes did not differ between the two groups. Our meta-analysis showed a first week sICH risk of 8.1% (95% confidence interval 3.9%-17.1%) in stroke patients with elevated INR treated with IAT.

CONCLUSION

The use of OACs, leading to an INR > 1.7, did not seem to increase the risk of an sICH in patients with an acute stroke treated with IAT.

Prothrombin complex concentrate facilitates emergency spinal surgery in anticoagulated patients

BACKGROUND

Oral anticoagulants are commonly used in the ageing population and therefore, spine surgeons are increasingly confronted with anticoagulated patients requiring surgical therapy. 'Bridging therapies' with heparins are established in elective settings, but the time frame for haemostasis restoration may be too long for patients presenting with acute spinal pathology and impending disability. The goal of this study was to analyse the feasibility of prothrombin complex concentrate (PCC) administration to facilitate emergency spinal surgery in anticoagulated patients.

METHOD

A retrospective analysis of the institutional database of neurosurgical patients receiving PCC from February 2007 to December 2013 (n = 485) identified 18 patients who received PCC prior to emergency spinal surgery. Clinical characteristics, as well as modalities of PCC administration and parameters of haemostasis were analysed. Furthermore, haemorrhagic complications and thromboembolic events in the further course were evaluated.

RESULTS

Spinal pathologies requiring urgent neurosurgical decompression were spinal haematoma (n = 9), spinal metastasis (n = 5), vertebral body fracture (n = 2), and disc herniation (n = 2). The mean international normalized ratio (INR) on admission was 2.27 ± 1.20 and after administration of PCC (mean: 1,944 ± 953 I.U.), INR significantly decreased to 1.12 ± 0.10 (p < 0.001). Emergency surgery was initiated within 4.4 h after PCC administration (range: 0-16.6 h). Postoperatively, symptoms improved in 12 patients (66.7 %). There were two deaths (11 %), one caused by acute myocardial infarction on the fourth postoperative day. Bleeding complications occurred in two patients (epidural haemorrhage n = 1, rectal tumour haemorrhage n = 1).

CONCLUSIONS

The administration of PCC facilitates emergency spinal surgery in anticoagulated patients who present with acute spinal pathology requiring urgent neurosurgical decompression. The risk of PCC-associated thromboembolic events seems to be low and justifies the use of PCC in order to avoid permanent disablement resulting from delayed surgery or non-operation.

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.

Rapid bedside coagulometry prior to urgent neurosurgical procedures in anticoagulated patients

INTRODUCTION

With the increased use of oral anticoagulation with vitamin K antagonists, emergency physicians encounter a growing number of patients requiring a rapid reversal of anticoagulant effects in order to perform urgent surgical procedures. Initiation of these procedures can be delayed because the coagulation status has to be assessed through examination of blood samples in central laboratories (CL). This delay may lead to negative effects, especially in potentially life-threatening conditions such as intracranial haemorrhage. Point-of-care (POC) devices for assessment of international normalized ratio (POC INR) have improved the management of anticoagulation therapy in the outpatient setting. The use of these devices may also have beneficial effects in the treatment of anticoagulated patients requiring urgent neurosurgical procedures. The primary aim of this study was to analyse the potential of POC-guided assessment of INR to reduce time to potentially life-saving neurosurgery in this setting. Feasibility and accuracy as well as the gain of time through the use of this device were analysed.

MATERIALS AND METHODS

The POC coagulometer CoaguChek XS(®) was used in 17 patients with a history of anticoagulant use and a condition requiring urgent anticoagulant reversal prior to neurosurgical procedures (burr-hole trepanation: n = 8, craniotomy: n = 7, laminectomy: n = 2).

RESULTS

No technical difficulties occurred and rapid assessment of INR was achieved in all cases within 2 min. POC INR values correlated well with CL INR assessment with a mean INR deviation of 0.036 ± 0.12. The mean gain of time through the use of the POC INR device compared with CL assessment of INR was 47 ± 6 min (range: 37-61 min).

CONCLUSION

Our initial experiences with a POC INR device in anticoagulated patients undergoing urgent neurosurgical procedures demonstrate that its use may contribute to an improved management of these patients.

The exact science of stroke thrombolysis and the quiet art of patient selection

The science of metric-based patient stratification for intravenous thrombolysis, revolutionized by the landmark National Institute of Neurological Disorders and Stroke trial, has transformed acute ischaemic stroke therapy. Recanalization of an occluded artery produces tissue reperfusion that unequivocally improves outcome and function in patients with acute ischaemic stroke. Recanalization can be achieved mainly through intravenous thrombolysis, but other methods such as intra-arterial thrombolysis or mechanical thrombectomy can also be employed. Strict guidelines preclude many patients from being treated by intravenous thrombolysis due to the associated risks. The quiet art of informed patient selection by careful assessment of patient baseline factors and brain imaging could increase the number of eligible patients receiving intravenous thrombolysis. Outside of the existing eligibility criteria, patients may fall into therapeutic 'grey areas' and should be evaluated on a case by case basis. Important factors to consider include time of onset, age, and baseline blood glucose, blood pressure, stroke severity (as measured by National Institutes of Health Stroke Scale) and computer tomography changes (as measured by Alberta Stroke Programme Early Computed Tomography Score). Patients with traditional contraindications such as wake-up stroke, malignancy or dementia may have the potential to receive benefit from intravenous thrombolysis if they have favourable predictors of outcome from both clinical and imaging criteria. A proportion of patients experience complications or do not respond to intravenous thrombolysis. In these patients, other endovascular therapies or a combination of both may be used to provide benefit. Although an evidence-based approach to intravenous thrombolysis for acute ischaemic stroke is pivotal, it is imperative to examine those who might benefit outside of protocol-driven practice.