Estimating the Quantitative Demand of NOAC Antidote Doses on Stroke Units

Medical gas plasma promotes blood coagulation via platelet activation

Major blood loss still is a risk factor during surgery. Electrocauterization often is used for necrotizing the tissue and thereby halts bleeding (hemostasis). However, the carbonized tissue is prone to falling off, putting patients at risk of severe side effects, such as dangerous internal bleeding many hours after surgery. We have developed a medical gas plasma jet technology as an alternative to electrocauterization and investigated its hemostatic (blood clotting) effects and mechanisms of action using whole human blood. The gas plasma efficiently coagulated anticoagulated donor blood, which resulted from the local lysis of red blood cells (hemolysis). Image cytometry further showed enhanced platelet aggregation. Gas plasmas release reactive oxygen species (ROS), but neither scavenging of long-lived ROS nor addition of chemically-generated ROS were able to abrogate or recapitulate the gas plasma effect, respectively. However, platelet activation was markedly impaired in platelet-rich plasma when compared to gas plasma-treated whole blood that moreover contained significant amounts of hemoglobin indicative of red blood cell lysis (hemolysis). Finally, incubation of whole blood with concentration-matched hemolysates phenocopied the gas plasmas-mediated platelet activation. These results will spur the translation of plasma systems for hemolysis into clinical practice.

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.

Successful intravenous thrombolysis in acute ischemic stroke after reversal of dabigatran etexilate with idarucizumab at the end of therapeutic time window

Dabigatran is a direct oral anticoagulant that is widely used for stroke prevention in patients with atrial fibrillation. We report a case of an 80-year-old stroke patient on dabigatran for permanent atrial fibrillation, who presented with an initial National Institutes of Health Stroke Scale (NIHSS) of 8. Dabigatran was reversed with idarucizumab, and intravenous tissue-type plasminogen activator (IV-tPA) was administrated beginning 4 h and 28 min after the symptom onset. The patient was discharged with an NIHSS of 1. Our case is an additional proof of safety and efficiency of idarucizumab in the clinical setting of ischemic stroke before the administration of IV-tPA.

Clinical presentation, diagnostic findings and management of cerebral ischemic events in patients on treatment with non-vitamin K antagonist oral anticoagulants - A systematic review

Background

Non-vitamin K antagonist oral anticoagulants (NOAC) are equally or potentially superior in terms of effectiveness in the prevention of ischemic stroke and carry a lower associated risk of intracranial hemorrhage compared to Vitamin K antagonists. Nevertheless, ischemic strokes also occur in patients who are being treated with NOAC. In those particular patients, knowledge about the underlying stroke etiology, clinical presentation, acute management, and complication rates is scarce.

Objective

Systematic literature review to provide a comprehensive clinical overview in terms of presentation, laboratory, imaging parameters and outcomes of patients suffering from acute cerebral ischemic events (i.e. TIA and acute ischemic stroke) while on treatment with a NOAC. Only if available, comparison to VKA is presented which was not the primary focus of this analysis.

Data sources

PubMed/MEDLINE, Scopus and EMBASE from January 1, 2006, to November 20, 2018.

Study eligibility criteria

52 studies providing detailed information on a total of 12247 patients were included. We excluded case reports and case series with less than five patients.

Study appraisal and synthesis method

We systematically assessed study quality using a bias tool and pooled consistent data.

Results

Existing data indicates milder stroke severity and smaller infarct size of acute ischemic stroke on treatment with NOAC compared to stroke occurrence on Vitamin K antagonists (VKA). Established risk factors for ischemic events also play a role in stroke while on NOACs, albeit the underlying etiology remains poorly understood. Intravenous thrombolysis and endovascular therapy seem to be safe and effective, but patient selection for recanalization therapies is challenging.

Limitations

Limited quality of published data, duplicate cases, statistical issues of data pooling, possible incomplete retrieval of identified research and reporting bias might have limited our findings.

Conclusions

Acute ischemic events despite treatment with NOAC therapy are insufficiently investigated.

Systematic review registration number

PROSPERO: CRD42018074853.

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.

Idarucizumab in Dabigatran-Treated Patients with Acute Ischemic Stroke Receiving Alteplase: A Systematic Review of the Available Evidence

BACKGROUND AND PURPOSE

Current guidelines do not recommend the use of intravenous recombinant tissue plasminogen activator in patients with acute ischemic stroke who receive direct oral anticoagulants. While the humanized monoclonal antibody idarucizumab can quickly reverse the anticoagulant effects of the thrombin inhibitor dabigatran, safety data for subsequent tissue plasminogen activator treatment are sparse. Here, we review current knowledge about dabigatran reversal prior to systemic reperfusion treatment in acute ischemic stroke.

METHODS

We performed a systematic review of all published cases of intravenous tissue plasminogen activator treatment following the administration of a dabigatran antidote up to June 2017 and added five unpublished cases of our own. We analyzed clinical and radiological outcomes, symptomatic post-thrombolysis intracranial hemorrhage, and other serious systemic bleeding. Additional endpoints were allergic reaction to idarucizumab, and venous thrombosis in the post-acute phase.

RESULTS

We identified a total of 21 patients (71% male) with a median age of 76 years (interquartile range 70-84). The median National Institute of Health Stroke Scale score at baseline was 10 (n = 20, interquartile range 5-11) and 18/20 patients (90%) had mild or moderate stroke severity. The time from symptom onset to start of tissue plasminogen activator was 155 min (n = 18, interquartile range 122-214). The outcome was unfavorable in 3/19 patients (16%). There was one fatality as a result of a symptomatic post-thrombolysis intracranial hemorrhage, and two patients experienced an increase in the National Institute of Health Stroke Scale compared with baseline. One patient had a recurrent stroke. No systemic bleeding, venous thrombosis, or allergic reactions were reported.

CONCLUSION

Experience with idarucizumab administration prior to tissue plasminogen activator treatment in acute ischemic stroke is limited. Initial clinical experience in less severe stroke syndromes and short time windows seems favorable. Larger cohorts are required to confirm safety, including bleeding complications and the risk of thrombosis.