Rivaroxaban versus aspirin for prevention of covert brain infarcts in patients with embolic stroke of undetermined source: NAVIGATE ESUS MRI substudy

Background

Covert brain infarcts are associated with important neurological morbidity. Their incidence in patients with embolic stroke of undetermined source (ESUS) is unknown.

Aims

To assess the incidence of covert brain infarcts and cerebral microbleeds using MRI in a prospective substudy of the NAVIGATE ESUS randomized trial and to evaluate the effects of antithrombotic therapies.

Methods

At 87 sites in 15 countries, substudy participants were randomly assigned to receive rivaroxaban 15 mg daily or aspirin 100 mg daily and underwent brain MRI near randomization and after study termination. The primary outcome was incident brain infarct (clinical ischemic stroke or covert brain infarct). Brain infarcts and microbleeds were ascertained centrally by readers unaware of treatment. Treatment effects were estimated using logistic regression.

Results

Among the 718 substudy participants with interpretable, paired MRIs, the mean age was 67 years and 61% were men with a median of 52 days between the qualifying ischemic stroke and randomization and a median of seven days between randomization and baseline MRI. During the median (IQR) 11 (12) month interval between scans, clinical ischemic strokes occurred in 27 (4%) participants, while 60 (9%) of the remaining participants had an incident covert brain infarct detected by MRI. Assignment to rivaroxaban was not associated with reduction in the incidence of brain infarct (OR 0.77, 95% CI 0.49, 1.2) or of covert brain infarct among those without clinical stroke (OR 0.85, 95% CI 0.50, 1.4). New microbleeds were observed in 7% and did not differ among those assigned rivaroxaban vs. aspirin (HR 0.95, 95% CI 0.52–1.7).

Conclusions

Incident covert brain infarcts occurred in twice as many ESUS patients as a clinical ischemic stroke. Treatment with rivaroxaban compared with aspirin did not significantly reduce the incidence of covert brain infarcts or increase the incidence of microbleeds, but the confidence intervals for treatment effects were wide.

Registration:https://www.clinicaltrials.gov. Unique identifier: NCT 02313909

Neurological Manifestations of COVID-19 and the Importance of Magnetic Resonance Imaging

A letter to the editor to discuss several uses of brain magnetic resonance imaging (MRI) in the investigation of neurological manifestations of covid-19. Described several situations in which the MRI is needed. Brain MRI is an important diagnostic method in the covid-19 scenario, to investigate possible neurological complications of the disease.

Rivaroxaban for Stroke Prevention after Embolic Stroke of Undetermined Source

BACKGROUND

Embolic strokes of undetermined source represent 20% of ischemic strokes and are associated with a high rate of recurrence. Anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, may result in a lower risk of recurrent stroke than aspirin.

METHODS

We compared the efficacy and safety of rivaroxaban (at a daily dose of 15 mg) with aspirin (at a daily dose of 100 mg) for the prevention of recurrent stroke in patients with recent ischemic stroke that was presumed to be from cerebral embolism but without arterial stenosis, lacune, or an identified cardioembolic source. The primary efficacy outcome was the first recurrence of ischemic or hemorrhagic stroke or systemic embolism in a time-to-event analysis; the primary safety outcome was the rate of major bleeding.

RESULTS

A total of 7213 participants were enrolled at 459 sites; 3609 patients were randomly assigned to receive rivaroxaban and 3604 to receive aspirin. Patients had been followed for a median of 11 months when the trial was terminated early because of a lack of benefit with regard to stroke risk and because of bleeding associated with rivaroxaban. The primary efficacy outcome occurred in 172 patients in the rivaroxaban group (annualized rate, 5.1%) and in 160 in the aspirin group (annualized rate, 4.8%) (hazard ratio, 1.07; 95% confidence interval [CI], 0.87 to 1.33; P=0.52). Recurrent ischemic stroke occurred in 158 patients in the rivaroxaban group (annualized rate, 4.7%) and in 156 in the aspirin group (annualized rate, 4.7%). Major bleeding occurred in 62 patients in the rivaroxaban group (annualized rate, 1.8%) and in 23 in the aspirin group (annualized rate, 0.7%) (hazard ratio, 2.72; 95% CI, 1.68 to 4.39; P<0.001).

CONCLUSIONS

Rivaroxaban was not superior to aspirin with regard to the prevention of recurrent stroke after an initial embolic stroke of undetermined source and was associated with a higher risk of bleeding. (Funded by Bayer and Janssen Research and Development; NAVIGATE ESUS ClinicalTrials.gov number, NCT02313909 .).

Global Survey of the Frequency of Atrial Fibrillation–Associated Stroke

Background and Purpose—

Atrial fibrillation (AF) is increasingly recognized as the single most important cause of disabling ischemic stroke in the elderly. We undertook an international survey to characterize the frequency of AF-associated stroke, methods of AF detection, and patient features.

Methods—

Consecutive patients hospitalized for ischemic stroke in 2013 to 2014 were surveyed from 19 stroke research centers in 19 different countries. Data were analyzed by global regions and World Bank income levels.

Results—

Of 2144 patients with ischemic stroke, 590 (28%; 95% confidence interval, 25.6–29.5) had AF-associated stroke, with highest frequencies in North America (35%) and Europe (33%) and lowest in Latin America (17%). Most had a history of AF before stroke (15%) or newly detected AF on electrocardiography (10%); only 2% of patients with ischemic stroke had unsuspected AF detected by poststroke cardiac rhythm monitoring. The mean age and 30-day mortality rate of patients with AF-associated stroke (75 years; SD, 11.5 years; 10%; 95% confidence interval, 7.6–12.6, respectively) were substantially higher than those of patients without AF (64 years; SD, 15.58 years; 4%; 95% confidence interval, 3.3–5.4; P <0.001 for both comparisons). There was a strong positive correlation between the mean age and the frequency of AF ( r =0.76; P =0.0002).

Conclusions—

This cross-sectional global sample of patients with recent ischemic stroke shows a substantial frequency of AF-associated stroke throughout the world in proportion to the mean age of the stroke population. Most AF is identified by history or electrocardiography; the yield of conventional short-duration cardiac rhythm monitoring is relatively low. Patients with AF-associated stroke were typically elderly (>75 years old) and more often women.

Rivaroxaban for secondary stroke prevention in patients with embolic strokes of undetermined source: Design of the NAVIGATE ESUS randomized trial

BACKGROUND

Embolic strokes of undetermined source comprise up to 20% of ischemic strokes. The stroke recurrence rate is substantial with aspirin, widely used for secondary prevention. The New Approach riVaroxaban Inhibition of Factor Xa in a Global trial versus ASA to prevenT Embolism in Embolic Stroke of Undetermined Source international trial will compare the efficacy and safety of rivaroxaban, an oral factor Xa inhibitor, versus aspirin for secondary prevention in patients with recent embolic strokes of undetermined source.

MAIN HYPOTHESIS

In patients with recent embolic strokes of undetermined source, rivaroxaban 15 mg once daily will reduce the risk of recurrent stroke (both ischemic and hemorrhagic) and systemic embolism (primary efficacy outcome) compared with aspirin 100 mg once daily.

DESIGN

Double-blind, randomized trial in patients with embolic strokes of undetermined source, defined as nonlacunar cryptogenic ischemic stroke, enrolled between seven days and six months from the qualifying stroke. The planned sample size of 7000 participants will be recruited from approximately 480 sites in 31 countries between 2014 and 2017 and followed for a mean of about two years until at least 450 primary efficacy outcome events have occurred. The primary safety outcome is major bleeding. Two substudies assess (1) the relative effect of treatments on MRI-determined covert brain infarcts and (2) the biological underpinnings of embolic strokes of undetermined source using genomic and biomarker approaches.

SUMMARY

The New Approach riVaroxaban Inhibition of Factor Xa in a Global trial versus ASA to prevenT Embolism in Embolic Stroke of Undetermined Source trial is evaluating the benefits and risks of rivaroxaban for secondary stroke prevention in embolic strokes of undetermined source patients. Main results are anticipated in 2018.

Embolic strokes of undetermined source: Prevalence and patient features in the ESUS Global Registry

Background

Recent evidence supports that most non-lacunar cryptogenic strokes are embolic. Accordingly, these strokes have been designated as embolic strokes of undetermined source (ESUS).

Aims

We undertook an international survey to characterize the frequency and clinical features of ESUS patients across global regions.

Methods

Consecutive patients hospitalized for ischemic stroke were retrospectively surveyed from 19 stroke research centers in 19 different countries to collect patients meeting criteria for ESUS.

Results

Of 2144 patients with recent ischemic stroke, 351 (16%, 95% CI 15% to 18%) met ESUS criteria, similar across global regions (range 16% to 21%), and an additional 308 (14%) patients had incomplete evaluation required for ESUS diagnosis. The mean age of ESUS patients (62 years; SD = 15) was significantly lower than the 1793 non-ESUS ischemic stroke patients (68 years, p ≤ 0.001). Excluding patients with atrial fibrillation ( n = 590, mean age = 75 years), the mean age of the remaining 1203 non-ESUS ischemic stroke patients was 64 years ( p = 0.02 vs. ESUS patients). Among ESUS patients, hypertension, diabetes, and prior stroke were present in 64%, 25%, and 17%, respectively. Median NIHSS score was 4 (interquartile range 2–8). At discharge, 90% of ESUS patients received antiplatelet therapy and 7% received anticoagulation.

Conclusions

This cross-sectional global sample of patients with recent ischemic stroke shows that one-sixth met criteria for ESUS, with additional ESUS patients likely among those with incomplete diagnostic investigation. ESUS patients were relatively young with mild strokes. Antiplatelet therapy was the standard antithrombotic therapy for secondary stroke prevention in all global regions.

Neurophysiological measurements of affected and unaffected motor cortex from a cross-sectional, multi-center individual stroke patient data analysis study

OBJECTIVES

Transcranial magnetic stimulation (TMS) has been used to measure cortical excitability as a functional measurement of corticomotor pathways. Given its potential application as an assessment tool in stroke, we aimed to analyze the correlation of TMS parameters with clinical features in stroke using data from 10 different centers.

METHODS

Data of 341 patients with a clinical diagnosis of stroke were collected from studies assessing cortical excitability using TMS. We used a multivariate regression model in which the baseline cortical excitability parameter "resting Motor Threshold (rMT)" was the main outcome and the demographic, anatomic and clinical characteristics were included as independent variables.

RESULTS

The variable "severity of motor deficit" consistently remained significant in predicting rMT in the affected hemisphere, with a positive β coefficient, in the multivariate models after sensitive analyses and adjusting for important confounders such as site center. Additionally, we found that the correlations between "age" or "time since stroke" and the rMT in the affected hemisphere were significant, as well as the interaction between "time since stroke" and "severity of motor deficit".

CONCLUSIONS

We have shown that severity of motor deficit is an important predictor for rMT in the affected hemisphere. Additionally, time since stroke seems to be an effect modifier for the correlation between motor deficit and rMT. In the unaffected motor cortex, these correlations were not significant. We discuss these findings in the context of stroke rehabilitation.

Abstract T MP53: Frequency Aad Features of Patients With Embolic Strokes of Underdetermined Source (esus): Esus Global Registry

Background: Embolic stroke of undetermined source (ESUS) is a recently introduced clinical construct to define non-lacunar cryptogenic ischemic stroke and is the basis for two large international randomized trials recently underway. Diagnostic criteria are a visualized non-lacunar stroke on CT or MRI, absence of atrial fibrillation by history, ECG and at least 24 hours of rhythm monitoring, absence of intracardiac thrombus by echocardiography, no occlusive atherosclerosis based on imaging of the cervical and intracranial arteries, and no specific cause of stroke identified. The frequency and features of ESUS patients have not been characterized previously.

Methods: Consecutive patients with recent ischemic stroke were retrospectively reviewed at 20 stroke research centers in 20 different countries to identify those meeting criteria for ESUS, as well as reasons not meeting criteria for the remaining patients.

Results: Of 2.090 patients with recent ischemic stroke, 18% met ESUS criteria (range 2% to 36%). Of those not meeting ESUS criteria, major reasons were atrial fibrillation (26%), lacunar stroke (19%), incomplete diagnostic evaluation (18%), carotid artery stenosis >50% (17%), and intracranial stenosis (13%). Excluding those without the required diagnostic evaluation, 22% met criteria for ESUS. Of the 378 ESUS patients, the mean age was 64 years (vs. 68 years for non-ESUS), 56% were men (54% non-ESUS), 16% received tPA, and 33% were taking antiplatelet therapy at stroke onset. Hypertension, diabetes, and coronary artery disease were present in 66%, 26%, and 11%, respectively. At hospital discharge, 93% received antiplatelet therapy, 6% anticoagulant therapy, and 1% no antithrombotic therapy.

Conclusions: Ischemic stroke patients meeting criteria for ESUS are not uncommon (22% of ischemic strokes) in stroke centers performing the required diagnostic evaluation. Antiplatelet therapy is overwhelmingly used for secondary prevention in these patients with non-lacunar cryptogenic stroke.

Interleukin-10 may protect against progressing injury during the acute phase of ischemic stroke

Atherosclerosis is an inflammatory disease, and ischemic stroke is one of its most common and devastating manifestations. Proinflammatory cytokines play a key role in the progression of the irreversible ischemic lesions. The presence of anti-inflammatory mediators may prevent secondary ischemic injury. Objectives 1) To assess the relationship between stroke severity and the serum levels of IL-1β, IL-2, and IL-10; and 2) To analyze the neurological outcome after 72 h of ischemic stroke onset and expression of interleukins. Method We measured the serum levels of IL-1β, IL-2, and IL-10 in 26 patients with acute stroke. Neurological impairment was scored using the National Institute of Health Stroke Scale within the first 72 h after stroke onset. Thirty healthy subjects were analyzed as controls. Results Patients with IL-10 <925.0 pg/mL presented with neurological deterioration within the first 72 h. Conclusion IL-10 may protect against ischemic injury during the acute phase of stroke.

Chlamydia pneumoniae and stroke: is there a direct relationship?

OBJECTIVE

To investigate the possible relationship between atherothrombotic stroke and Chlamydia pneumoniae.

METHOD

150 patients with carotid atherothrombosis were enrolled. The casuistic was divided in three groups: ischemic stroke (IS): 65 patients; transient ischemic attack (TIA): 26 patients; and control: 59. The IS or TIA onset was up to 30 days from the beginning of the study. Carotid atheromatoses was diagnosed by Doppler-ultrasonography. Patients with cardioembolic risk or non-atherothrombotic origin were excluded. Comparisons were done between the three groups, and within each group according to the different age sub-groups, to the main arteries affected, and to the atherogenic risk factors. Bacteria detection was done using polimerase chain reaction.

RESULTS

Only one patient tested positive for C. pneumoniae belonging to the control group.

CONCLUSION

These results do not suggest that C. pneumoniae participated in the onset of IS or TIA or that it has a role in carotid plaque destabilization.

Chlamydia pneumoniae and symptomatic carotid atherosclerotic plaque: a prospective study

OBJECTIVE

To investigate the possible link between symptomatic carotid atherosclerotic plaque and Chlamydia pneumoniae.

BACKGROUND

Recently, several studies have demonstrated that there may be a possible link between Chlamydia pneumonia and carotid atherosclerosis, however the real role of Chlamydia pneumoniae is not completely understood.

METHOD

This is a prospective study with a total of 52 patients analyzed. All patients had been submitted to endarterectomy, and had suffered thrombotic ischemic stroke or transient ischemic attack up to 60 days prior to the surgery. Every patient presented carotid stenosis over 70%. The plaque was removed during the surgery and the laboratory exams were immediately done. Evaluation of Chlamydia pneumoniae DNA was done using polymerase chain reaction (PCR).

RESULTS

The PCR analyses of all 52 patients were negative for Chlamydia pneumoniae.

CONCLUSION

These initial results do not show a relationship between Chlamydia pneumoniae and symptomatic carotid atherosclerotic plaque.

[Neuroprotective agents in stroke: national opinion]

The Brazilian Stroke Society constituted a committee composed by specialists from different areas of Brazil that emitted a viewpoint called "National Opinion", written similar to the consensus pattern. The study purpose is to guide and offer subsidies for diagnosis and therapeutical plans for different situations in cerebrovascular diseases. The current article analyses "neuroprotective agents in stroke", discussing the level of evidence for the use of potential neuroprotective drugs and ongoing clinical trials.

Reversal of parkinsonism and portosystemic encephalopathy following embolization of a congenital intrahepatic venous shunt: brain MR imaging and 1H spectroscopic findings

Parkinsonism and portosystemic encephalopathy (PSE) are cerebral disorders associated with motor and neuropsychological dysfunctions that may occur in patients with chronic liver disease. We describe a patient with parkinsonism and neuroradiologic and 1H spectroscopic findings of PSE associated with a large congenital intrahepatic portosystemic venous shunt. Chronic liver disease was absent. After endovascular treatment, we documented a progressive reversal of parkinsonism and PSE on the basis of clinical, neuroradiologic, and spectroscopic criteria.

Neuroprotection, excitotoxicity and NMDA antagonists

PURPOSE

To analyze the main aspects of neuroprotection and excitotoxicity.

DISCUSSION

This is a significant theory on the pathophysiology of cerebral ischemia; it is based on the release of excitatory aminoacid (EAA), mainly glutamate. The sequence starts with a decrease of the blood flow and ends in neuronal death. The main stages of this reaction are herein presented and discussed. An in depth study of the effects of the excessive intracellular calcium is undertaken. Neuroprotectors (NP) are a group of drugs that reduce the excitotoxicity, opposing the excessive release of EAA and its intracellular effects. Neuroprotectors represent a rational approach to stroke treatment and offer a number of potential advantages. They prevent or limit ischemia-induced damage.

CONCLUSION

There are many experimental and clinical NP trials. A minimum of 800 trials are currently under study worldwide. The most important NP subgroups are: N-methyl D-aspartate (NMDA) antagonists, gamma-amino butyric acid (GABA) agonists, amino-hydroxy-methyl-isoxalone propionic acid (AMPA) antagonists, reducers of intracellular Ca++ inhibitors of nitric oxide modulation pathway free radicals scavengers, sodium channel antagonists, glutamate release inhibitor, growth factors, hypothermia and potassium channel activators.

[Comparison between HDL and LDL cholesterol as risk factors for carotid atherosclerosis]

In order to find out whether there exists a relationship between HDL and LDL serum levels and atherosclerotic plaques in the carotid artery (CA), a prospective study was carried out involving 125 patients. They were aleatorily included, of both sexes and age between 45-75 years old. HDL and LDL serum levels were measured as well CA ultrasonographic mode B investigated. It was verified that the number of patients having atherosclerotic plaques in CA was inversely proportional to the HDL levels. We came up with the same ratio when the HDL levels were compared to the number of patients having CA stenosis. These results were statistically significant (x2 = 6.57 and x2 = 9.24 respectively; critical x2 = 5.99 to alpha = 5%). A direct ratio was also found out in the relationship between the presence of atherosclerotic plaques in the CA and the LDL serum levels (greater in patients with plaques). However no relationship between LDL levels and the occurrence or not of CA stenosis in patients having plaques was demonstrated. The results were not statistically significant (x2 = 0.97 and x2 = 0.41, respectively, critical x2 = 5.99 to alpha = 5%). The obtained results seem to be at least in part in agreement with literature findings. Statistically significative results in the comparison of HDL and LDL levels with the grade of stenosis of the CA were not found out (x2 = 11.78 and x2 = 4.03, respectively; critical x2 = 12.59 to alpha = 5%).

[Cerebral infarction and edema: prognostico-evolutional evaluation by neurologic signs]

The prospective study in question involves 92 patients with cerebral infarction (CI). The follow-up was carried out for 10 days with daily evaluation, and the patients were graded for the different indicators usually researched in such cases. The observations were analysed by comparing the individual indicator averages, taken over all the patients, with the global mean of all the observed values. The analysis shows that the result of the "consciousness" exam alone is the best clinical parameter to ascertain the evolution of the patient after CI.

[Evaluation of glycerol in the treatment of cerebral infarction]

A prospective study was undertaken concerning patients with cerebral ischemia for evaluation of glycerol treatment. This medication acts on edema produced by cerebral ischemia; the edema being the main factor that worsens patients with cerebral ischemia. 187 patients were studied specifically for cerebral edema. They were randomly divided into two groups: the first group of 92 patients did not receive anti-edema treatment; the second group of 95 patients was divided into sub-groups according to age and severity of neurological involvement. The use of glycerol was found to be beneficial in all groups treated.

[Prognostic value of potassium and sodium levels in cerebrospinal fluid and blood in patients with coma. Study of 55 cases]

This is a prospective study, with 55 patients in coma, in which wasn't chosen sex, age, intensity of coma or etiology. It was measured the concentration of the potassium and the sodium in cerebrospinal fluid, (CSF) and in the serum, to find an auxiliary way to value the prognostic. It is known that the potassium in the CSF is extremely stable, and it maintains the tax without alterations, even when the potassium in CSF is rapid and intensity raised after death. Experimental studies show the potassium raised in CSF in serious damaged brain. Our results show, in patients who recovered consciousness, normal values (means 2,61 mEq/1) of potassium in CSF. The mean of values of potassium in CSF in the group of patients who had bad evolution (they died) show index estatisticaly up of normal values (2,97 mEq/1) and this shows a serious damaged brain and/or irreversible, able to affect the stability of CSF potassium. These index are present in some kind of coma or etiology, showing that raised potassium in CSF, indicates bad prognostic, in some kind of coma. With the sodium, the results show that this ion doesn't serve to this finality, because its concentrations isn't stable in CSF, and change with the blood alterations of natremia.

[Prognostic-evolutive evaluation of patients in coma based on ocular reflexes]

The ocular reflexes (ciliospinal, photomotor, oculocephalic, vestibulo-ocular, corneal) were studied in 84 comatose patients. The scope of the investigation was the assessment of each reflex in terms of its resistance according to the degree of depth of the coma. From the statistical viewpoint it was possible to emphasize the photomotor, corneal and vestibulo-ocular as the most resistant ones. The periodic evaluation in short time intervals of these five reflexes, observing their extinction or their re-appearance, permits a better prognostic assessment in a longitudinal viewpoint of the comatose patient.