Outcome after acute ischemic stroke is linked to sex-specific lesion patterns.

Acute ischemic stroke affects men and women differently. In particular, women are often reported to experience higher acute stroke severity than men. We derived a low-dimensional representation of anatomical stroke lesions and designed a Bayesian hierarchical modeling framework tailored to estimate possible sex differences in lesion patterns linked to acute stroke severity (National Institute of Health Stroke Scale). This framework was developed in 555 patients (38% female). Findings were validated in an independent cohort (n = 503, 41% female). Here, we show brain lesions in regions subserving motor and language functions help explain stroke severity in both men and women, however more widespread lesion patterns are relevant in female patients. Higher stroke severity in women, but not men, is associated with left hemisphere lesions in the vicinity of the posterior circulation. Our results suggest there are sex-specific functional cerebral asymmetries that may be important for future investigations of sex-stratified approaches to management of acute ischemic stroke.

Characteristics of Recurrent Ischemic Stroke After Embolic Stroke of Undetermined Source: Secondary Analysis of a Randomized Clinical Trial.

Importance: The concept of embolic stroke of undetermined source (ESUS) unifies a subgroup of cryptogenic strokes based on neuroimaging, a defined minimum set of diagnostic tests, and exclusion of certain causes. Despite an annual stroke recurrence rate of 5%, little is known about the etiology underlying recurrent stroke after ESUS. Objective: To identify the stroke subtype of recurrent ischemic strokes after ESUS, to explore the interaction with treatment assignment in each category, and to examine the consistency of cerebral location of qualifying ESUS and recurrent ischemic stroke. Design, Setting, and Participants: The NAVIGATE-ESUS trial was a randomized clinical trial conducted from December 23, 2014, to October 5, 2017. The trial compared the efficacy and safety of rivaroxaban and aspirin in patients with recent ESUS (n = 7213). Ischemic stroke was validated in 309 of the 7213 patients by adjudicators blinded to treatment assignment and classified by local investigators into the categories ESUS or non-ESUS (ie, cardioembolic, atherosclerotic, lacunar, other determined cause, or insufficient testing). Five patients with recurrent strokes that could not be defined as ischemic or hemorrhagic in absence of neuroimaging or autopsy were excluded. Data for this secondary post hoc analysis were analyzed from March to June 2019. Interventions: Patients were randomly assigned to receive rivaroxaban, 15 mg/d, or aspirin, 100 mg/d. Main Outcomes and Measures: Association of recurrent ESUS with stroke characteristics. Results: A total of 309 patients (205 men [66%]; mean [SD] age, 68 [10] years) had ischemic stroke identified during the median follow-up of 11 (interquartile range [IQR], 12) months (annualized rate, 4.6%). Diagnostic testing was insufficient for etiological classification in 39 patients (13%). Of 270 classifiable ischemic strokes, 156 (58%) were ESUS and 114 (42%) were non-ESUS (37 [32%] cardioembolic, 26 [23%] atherosclerotic, 35 [31%] lacunar, and 16 [14%] other determined cause). Atrial fibrillation was found in 27 patients (9%) with recurrent ischemic stroke and was associated with higher morbidity (median change in modified Rankin scale score 2 [IQR, 3] vs 0 (IQR, 1]) and mortality (15% vs 1%) than other causes. Risk of recurrence did not differ significantly by subtype between treatment groups. For both the qualifying and recurrent strokes, location of infarct was more often in the left (46% and 54%, respectively) than right hemisphere (40% and 37%, respectively) or brainstem or cerebellum (14% and 9%, respectively). Conclusions and Relevance: In this secondary analysis of randomized clinical trial data, most recurrent strokes after ESUS were embolic and of undetermined source. Recurrences associated with atrial fibrillation were a minority but were more often disabling and fatal. More extensive investigation to identify the embolic source is important toward an effective antithrombotic strategy. Trial Registration: ClinicalTrials.gov Identifier: NCT02313909.

Hematoma location and morphology of anticoagulation-associated intracerebral hemorrhage.

OBJECTIVE: To study hematoma location and morphology of intracerebral hemorrhage (ICH) associated with oral anticoagulants (OAC) and delineate causes and mechanism. METHODS: We performed a systematic literature research and meta-analysis of studies comparing neuroimaging findings in patients with OAC-ICH compared to those with ICH not associated with OAC (non-OAC ICH). We calculated pooled risk ratios (RRs) for ICH location using the Mantel-Haenszel random-effects method and corresponding 95% confidence intervals (95% CI). RESULTS: We identified 8 studies including 6,259 patients (OAC-ICH n = 1,107, pooled OAC-ICH population 17.7%). There was some evidence for deep ICH location (defined as ICH in the thalamus, basal ganglia, internal capsule, or brainstem) being less frequent in patients with OAC-ICH (OAC-ICH: 450 of 1,102/40.8% vs non-OAC ICH: 2,656 of 4,819/55.1%; RR 0.94, 95% CI 0.88-1.00, p = 0.05, I 2 = 0%) while cerebellar ICH location was significantly more common in OAC-ICH (OAC-ICH: 111 of 1,069/10.4% vs non-OAC ICH: 326 of 4,787/6.8%; RR 1.45, 95% CI 1.12-1.89, p = 0.005, I 2 = 21%) compared to non-OAC ICH. There was no statistically significant relationship to OAC use for lobar (OAC-ICH: 423 of 1,107/38.2% vs non-OAC ICH: 1,884 of 5,152/36.6%; RR 1.02, 95% CI 0.89-1.17, p = 0.75, I 2 = 53%, p for heterogeneity = 0.04) or brainstem ICH (OAC-ICH: 36 of 546/6.6% vs non-OAC ICH: 172 of 2,626/6.5%; RR 1.04, 95% CI 0.58-1.87, p = 0.89, I 2 = 59%, p for heterogeneity = 0.04). The risk for intraventricular extension (OAC-ICH: 436 of 840/51.9% vs non-OAC ICH: 1,429 of 3,508/40.7%; RR 1.26, 95% CI 1.16-1.36, p < 0.001, I 2 = 0%) was significantly increased in patients with OAC-ICH. We found few data on ICH morphology in OAC-ICH vs non-OAC ICH. CONCLUSION: The overrepresentation of cerebellar ICH location and intraventricular extension in OAC-ICH might have mechanistic relevance for the underlying arteriopathy, pathophysiology, or bleeding pattern of OAC-ICH, and should be investigated further.

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 .).

Early Recurrence and Major Bleeding in Patients With Acute Ischemic Stroke and Atrial Fibrillation Treated With Non-Vitamin-K Oral Anticoagulants (RAF-NOACs) Study.

BACKGROUND: The optimal timing to administer non-vitamin K oral anticoagulants (NOACs) in patients with acute ischemic stroke and atrial fibrillation is unclear. This prospective observational multicenter study evaluated the rates of early recurrence and major bleeding (within 90 days) and their timing in patients with acute ischemic stroke and atrial fibrillation who received NOACs for secondary prevention. METHODS AND RESULTS: Recurrence was defined as the composite of ischemic stroke, transient ischemic attack, and symptomatic systemic embolism, and major bleeding was defined as symptomatic cerebral and major extracranial bleeding. For the analysis, 1127 patients were eligible: 381 (33.8%) were treated with dabigatran, 366 (32.5%) with rivaroxaban, and 380 (33.7%) with apixaban. Patients who received dabigatran were younger and had lower admission National Institutes of Health Stroke Scale score and less commonly had a CHA2DS2-VASc score >4 and less reduced renal function. Thirty-two patients (2.8%) had early recurrence, and 27 (2.4%) had major bleeding. The rates of early recurrence and major bleeding were, respectively, 1.8% and 0.5% in patients receiving dabigatran, 1.6% and 2.5% in those receiving rivaroxaban, and 4.0% and 2.9% in those receiving apixaban. Patients who initiated NOACs within 2 days after acute stroke had a composite rate of recurrence and major bleeding of 12.4%; composite rates were 2.1% for those who initiated NOACs between 3 and 14 days and 9.1% for those who initiated >14 days after acute stroke. CONCLUSIONS: In patients with acute ischemic stroke and atrial fibrillation, treatment with NOACs was associated with a combined 5% rate of ischemic embolic recurrence and severe bleeding within 90 days.

Stroke Thrombolysis in a Centralized and a Decentralized System (Helsinki and Telemedical Project for Integrative Stroke Care Network).

BACKGROUND AND PURPOSE: Intravenous thrombolysis with tissue-type plasminogen activator (tPA) for acute ischemic stroke is more effective when delivered early. Timely delivery is challenging particularly in rural areas with long distances. We compared delays and treatment rates of a large, decentralized telemedicine-based system and a well-organized, large, centralized single-hospital system. METHODS: We analyzed the centralized system of the Helsinki University Central Hospital (Helsinki and Province of Uusimaa, Finland, 1.56 million inhabitants, 9096 km2) and the decentralized TeleStroke Unit network in a predominantly rural area (Telemedical Project for Integrative Stroke Care [TEMPiS], South-East Bavaria, Germany, 1.94 million inhabitants, 14 992 km2). All consecutive tPA treatments were prospectively registered. We compared tPA rates per total ischemic stroke admissions in the Helsinki and TEMPiS catchment areas. For delay comparisons, we excluded patients with basilar artery occlusions, in-hospital strokes, and those being treated after 270 minutes. RESULTS: From January 1, 2011, to December 31, 2013, 912 patients received tPA in Helsinki University Central Hospital and 1779 in TEMPiS hospitals. Area-based tPA rates were equal (13.0% of 7017 ischemic strokes in the Helsinki University Central Hospital area versus 13.3% of 14 637 ischemic strokes in the TEMPiS area; P=0.078). Median prehospital delays were longer (88; interquartile range, 60-135 versus 65; 48-101 minutes; P<0.001) but in-hospital delays were shorter (18; interquartile range, 13-30 versus 39; 26-56 minutes; P<0.001) in Helsinki University Central Hospital compared with TEMPiS with no difference in overall delays (117; interquartile range, 81-168 versus 115; 87-155 minutes; P=0.45). CONCLUSIONS: A decentralized telestroke thrombolysis service can achieve similar treatment rates and time delays for a rural population as a centralized system can achieve for an urban population.

Retinal origin of electrically evoked potentials in response to transcorneal alternating current stimulation in the rat.

PURPOSE: Little is known about the physiological mechanisms underlying the reported therapeutic effects of transorbital alternating current stimulation (ACS) in vision restoration, or the origin of the recorded electrically evoked potentials (EEPs) during such stimulation. We examined the issue of EEP origin and electrode configuration for transorbital ACS and characterized the physiological responses to CS in different structures of the visual system. METHODS: We recorded visually evoked potentials (VEPs) and EEPs from the rat retina, visual thalamus, tectum, and visual cortex. The VEPs were evoked by light flashes and EEPs were evoked by electric stimuli delivered by two electrodes placed either together on the same eye or on the eyeball and in the neck. Electrically evoked potentials and VEPs were recorded before and after bilateral intraorbital injections of tetrodotoxin that blocked retinal ganglion cell activity. RESULTS: Tetrodotoxin abolished VEPs at all levels in the visual pathway, confirming successful blockage of ganglion cell activity. Tetrodotoxin also abolished EEPs and this effect was independent of the stimulating electrode configurations. CONCLUSIONS: Transorbital electrically evoked responses in the visual pathway, irrespective of reference electrode placement, are initiated by activation of the retina and not by passive conductance and direct activation of neurons in other visual structures. Thus, placement of stimulating electrodes exclusively around the eyeball may be sufficient to achieve therapeutic effects.

Decompressive craniectomy for intracerebral hemorrhage.

OBJECTIVE: Intracerebral hemorrhage (ICH) has a high mortality rate and leaves most survivors disabled. The dismal outcome is mostly due to the mass effect of hematoma plus edema. Major clinical trials show no benefit from surgical or medical treatment. Decompressive craniectomy has, however, proven beneficial for large ischemic brain infarction with massive swelling. We hypothesized that craniectomy can improve ICH outcome as well. METHODS: We used the model of autologous blood injection into the basal ganglia in rats. After induction of ICH and then magnetic resonance imaging, animals were randomly allocated to groups representing no craniectomy (n = 10) or to craniectomy at 1, 6, or 24 hours. A fifth group without ICH underwent craniectomy only. Neurological and behavioral outcomes were assessed on days 1, 3, and 7 after ICH induction. Furthermore, terminal deoxynucleotidyl transferase dUTP nick-end labeling-positive cells were counted. RESULTS: After 7 days, compared with the ICH + no craniectomy group, all craniectomy groups had strikingly lower mortality (P < 0.01), much better neurological outcome (P < 0.001), and more favorable behavioral outcome. A trend occurred in the ICH + no craniectomy group toward more robust apoptosis. CONCLUSION: Decompressive craniectomy performed up to 24 hours improved outcome after experimental ICH, with earlier intervention of greater benefit.