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Background: As access to patient emboli is limited, embolus analogs (EAs) have become critical to the research of large vessel occlusion (LVO) stroke and the development of thrombectomy technology. To date, techniques for fabricating standardized human blood-derived EAs are limited in the variety of compositions, and the mechanical properties relevant to thrombectomy are not quantified., Methods: EAs were made by mixing human banked red blood cells (RBCs), plasma, and platelet concentrate in 10 different volumetric percentage combinations to mimic the broad range of patient emboli causing LVO strokes. The samples underwent histologic analysis and tensile testing to mimic the pulling action of thrombectomy devices, and were compared to patient emboli., Results: EAs had histologic compositions of 0-96% RBCs, 0.78%-92% fibrin, and 2.1%-22% platelets, which can be correlated with the ingredients using a regression model. At fracture, EAs elongated from 81% to 136%, and the ultimate tensile stress ranged from 16 to 949 kPa. These EAs' histologic compositions and tensile properties showed great similarity to those of emboli retrieved from LVO stroke patients, indicating the validity of such EA fabrication methods. EAs with lower RBC and higher fibrin contents are more extensible and can withstand higher tensile stress., Conclusions: EAs fabricated and tested using the proposed new methods provide a platform for stroke research and pre-clinical development of thrombectomy devices., Competing Interests: Declarations of Competing Interest LES is a founder of Endovascular Engineering Inc., Ann Arbor, Michigan. YL serves on the Scientific Advisory Board of this company. This company is indirectly related to this manuscript as it's developing medical devices for thrombectomy., (Copyright © 2020 Elsevier Inc. All rights reserved.)

An 82-year-old man with advanced lung cancer who had declined aggressive therapy was transferred to our hospital due to sudden-onset consciousness disturbance, global aphasia, and right hemiplegia. An electrocardiogram showed atrial fibrillation, and brain MRI and MRA revealed acute ischemic lesions of the left hemisphere and occlusion of the left internal carotid artery (ICA), respectively. We diagnosed acute ischemic stroke due to left ICA occlusion and performed endovascular thrombectomy, which resulted in complete recanalization of the left ICA after retrieval of the culprit embolus. Pathological examination of the retrieved thrombus revealed the presence of tumor tissue, as well as fibrin or red blood cells. Treatment was continued after admission, but the patient died of respiratory failure on day 40 of hospitalization. Autopsy revealed invasion of the tumor in the pulmonary vein, but not in the wall of the left atrium where thrombi were present. However, pathological examination of these thrombi in the left atrium revealed tumor tissue, along with fibrin or red blood cells. These findings suggest that the wall of the left atrium, in which lung cancer had not invaded, may be an incubator of a mixed embolus containing tumor tissue and thrombi in a case of cerebral embolism associated with both lung cancer and atrial fibrillation.

Background and Purpose: One-fifth of ischemic strokes are embolic strokes of undetermined source (ESUS). Their theoretical causes can be classified as cardioembolic versus noncardioembolic. This distinction has important implications, but the categories' proportions are unknown., Methods: Using data from the Cornell Acute Stroke Academic Registry, we trained a machine-learning algorithm to distinguish cardioembolic versus non-cardioembolic strokes, then applied the algorithm to ESUS cases to determine the predicted proportion with an occult cardioembolic source. A panel of neurologists adjudicated stroke etiologies using standard criteria. We trained a machine learning classifier using data on demographics, comorbidities, vitals, laboratory results, and echocardiograms. An ensemble predictive method including L1 regularization, gradient-boosted decision tree ensemble (XGBoost), random forests, and multivariate adaptive splines was used. Random search and cross-validation were used to tune hyperparameters. Model performance was assessed using cross-validation among cases of known etiology. We applied the final algorithm to an independent set of ESUS cases to determine the predicted mechanism (cardioembolic or not). To assess our classifier's validity, we correlated the predicted probability of a cardioembolic source with the eventual post-ESUS diagnosis of atrial fibrillation., Results: Among 1083 strokes with known etiologies, our classifier distinguished cardioembolic versus noncardioembolic cases with excellent accuracy (area under the curve, 0.85). Applied to 580 ESUS cases, the classifier predicted that 44% (95% credibility interval, 39%-49%) resulted from cardiac embolism. Individual ESUS patients' predicted likelihood of cardiac embolism was associated with eventual atrial fibrillation detection (OR per 10% increase, 1.27 [95% CI, 1.03-1.57]; c-statistic, 0.68 [95% CI, 0.58-0.78]). ESUS patients with high predicted probability of cardiac embolism were older and had more coronary and peripheral vascular disease, lower ejection fractions, larger left atria, lower blood pressures, and higher creatinine levels., Conclusions: A machine learning estimator that distinguished known cardioembolic versus noncardioembolic strokes indirectly estimated that 44% of ESUS cases were cardioembolic.

Background: Arterial thoracic outlet syndrome is a rare condition characterized by a subclavian artery pathology associated with a bone abnormality. It is rarely associated with thromboembolic stroke. The mechanism of cerebral embolism associated with thoracic outlet syndrome have rarely been demonstrated. We present here a fully studied case with a high probability of reverse flow embolism., Case Presentation: A 24-year-old man with a known arterial thoracic outlet syndrome presented with a right cerebral posterior artery brain infarction. An ultrasound examination depicted the compression of the right subclavian artery in the scalene defile with a post stenotic aneurysm and the presence of a floating thrombus in this aneurysm. There was a reverse flow during diastole in this aneurysm. Anticoagulation was carried out with the disappearance of the floating thrombus with no new clinical or brain MRI event. Corrective surgery of this thoracic outlet syndrome was performed one month after stroke., Conclusion: Very few cases of stroke in arterial thoracic outlet syndrome have been described with thorough dynamic vascular imaging. To our knowledge, this is the fourth reported case that advocates for a reverse flow embolism mechanism in stroke associated with thoracic outlet syndrome, and the first to realize an extensive ultrasound and doppler workup.

Background and Purpose: Detailed insight into the composition of thrombi retrieved from patients with ischemic stroke by mechanical thrombectomy might improve pathophysiologic understanding and therapy. Thus, this study searched for links between histologic thrombus composition and stroke subtypes and mechanical thrombectomy results., Materials and Methods: Thrombi from 85 patients who had undergone mechanical thrombectomy for acute ischemic stroke between December 2016 and March 2018 were studied retrospectively. Thrombi were examined histologically. Preinterventional imaging features, stroke subtypes, and interventional parameters were re-analyzed. Statistical analysis was performed with the Kruskal-Wallis test, Mann-Whitney U test, or Spearman correlation as appropriate., Results: Cardioembolic thrombi had a higher percentage of macrophages and a tendency toward more platelets than thrombi of large-artery atherosclerotic stenosis ( P = .021 and .003) or the embolic stroke of undetermined source ( P = .037 and .099) subtype. Thrombi prone to fragmentation required the combined use of contact aspiration and stent retrieval ( P = .021) and were associated with an increased number of retrieving maneuvers ( P = .001), longer procedural times ( P = .001), and a higher lymphocyte content ( P = .035)., Conclusions: We interpreted the higher macrophage and platelet content in cardioembolic thrombi compared with large-artery atherosclerotic stenosis or embolic stroke of undetermined source thrombi as an indication that the latter type might be derived from an atherosclerotic plaque rather than from an undetermined cardiac source. The extent of thrombus fragmentation was associated with a more challenging mechanical thrombectomy and a higher lymphocyte content of the thrombi. Thus, thrombus fragmentation not only might be caused by the recanalization procedure but also might be a feature of a lymphocyte-rich, difficult-to-retrieve subgroup of thrombi., (© 2020 by American Journal of Neuroradiology.)

Background and Purpose:  Cardioembolism is a postulated mechanism of embolic stroke of undetermined source (ESUS). We investigated endothelial glycocalyx, aortic elastic properties, oxidative stress, and their association with left atrial (LA) function in ESUS and healthy individuals., Methods:  In 90 ESUS patients (age 50.4 ± 13.2) and 90 controls with similar risk factors, we measured: (1) perfused boundary region (PBR) of the sublingual arterial microvessels (range 5-25 µm), a marker inversely related with glycocalyx thickness, (2) pulse wave velocity (PWV), central systolic blood pressure (cSBP), and augmentation index (AIx), (3) LA volume and strain using speckle-tracking imaging, and (4) malondialdehyde (MDA) and protein carbonyls (PCs), as oxidative stress markers., Results:  Compared with controls, ESUS had higher PWV, PBR, MDA, and PC levels as well as higher LA volume and reduced reservoir LA strain ( p  < 0.05). PBR > 1.2 μm of microvessel ranging from 5 to 9 μm and PWV > 10.2 m/s were associated with ESUS on multivariable analysis (odds ratio: 2.374 and 5.429, p  < 0.05, respectively) and increased the c-statistic of the initial model from 0.54 to 0.71. In ESUS, glycocalyx damage (increased PBR) was related with increased PWV ( p  < 0.01) which was linked with LA reservoir strain after controlling for age, sex, and risk factors ( p  = 0.03). Increased MDA and PC were related with glycocalyx damage, increased PWV ( r  = 0.67 and r  = 0.52), AIx, cSBP, and aortic atheroma ( p  < 0.01)., Conclusion:  Arterial function and endothelial glycocalyx are severely impaired in ESUS and are linked to LA dysfunction suggesting their contribution to ESUS pathogenesis., Clinical Trial Registration:  URL-http://www.clinicaltrials.gov. Unique identifier: NCT03609437., Competing Interests: None declared., (Georg Thieme Verlag KG Stuttgart · New York.)

Background: A revised classification of cerebellar infarctions (CI) may uncover unrecognized associations with etiologic stroke subtypes. We hypothesized that obliquely oriented small cortical cerebellar infarction (SCCI) representing end zone infarctions on MRI would be associated with cardiac embolism., Methods: We retrospectively analyzed consecutive stroke patients recruited between January-December 2016 in our center. Analyzed baseline characteristics: sex, age, cardiovascular risk factors, history of stroke or atrial fibrillation (AF). TOAST classification was used for determining stroke subtype. Acute infarction location (anterior/posterior/mixed anterior-posterior circulation), acute uni- or multiterritorial infarction, and acute or chronic CI/SCCI/non-SCCI were assessed by MRI, and vertebrobasilar stenosis/occlusion by vessel imaging. Pre-specified analysis was also performed in patients without known high cardioembolic risk (known AF history or acute multiterritorial infarction)., Results: We included 452 patients (CI in 154, isolated SCCI in 55, isolated non-SCCI in 50, and mixed SCCI/non-SCCI in 49). Both SCCI and non-SCCI were associated with AF history (SCCI, p = 0.021; non-SCCI, p = 0.004), additional acute posterior circulation infarction (p < 0.001 both CI-subtypes), multiterritorial infarctions (SCCI, p = 0.003; non-SCCI, p < 0.001) and cardioembolic more frequent than large-artery atherosclerosis origin (p < 0.001 for both CI-subtypes). SCCI was associated with older age (p < 0.001), whereas non-SCCI was associated with stroke history (p = 0.036) and vertebrobasilar stenosis/occlusion (p = 0.002). SCCI were older (p = 0.046) than non-SCCI patients, had less frequently prior stroke (p < 0.001), and more frequent cardioembolic infarction (p = 0.025). In patients without known high cardioembolic risk (n = 348), SCCI was strongly associated with subsequent cardioembolism diagnosis (OR 3.00 [CI 1.58-5.73, p < 0.001]). No such association was present in non-SCCI., Conclusions: Acute or chronic SCCI are strongly associated with a cardioembolic origin.

Background: Instability of atherosclerotic plaques is associated with the occurrence of stroke. Microembolic signals (MESs) are an indicator of unstable plaque. A relationship between plasma osteoprotegerin (OPG) and ischemic stroke has already been identified. The aim of this study was to investigate whether plasma OPG levels have a relationship with MESs and to evaluate the feasibility of OPG as a biomarker of stroke severity and occurrence of MESs., Methods: Our study consisted of 127 patients with large artery atherosclerosis stroke and 56 controls. Patients were classified into subgroups based on stroke severity and the occurrence of MESs. MES-monitoring was performed for 60 min using transcranial Doppler within 72 h of stroke onset. Stroke severity at admission was assessed by the National Institutes of Health Stroke Scale., Results: Plasma OPG levels were significantly associated with stroke, MESs, and stroke severity at admission (adjusted OR [95% CI]: 1.002 [1.001-1.003] p < 0.001; 1.002 [1.001-1.003] p = 0.001; 1.001 [1.000-1.002] p = 0.028). When plasma OPG levels were used to determine the stroke severity, the area under the receiver-operating characteristic curve (AUC) was 0.734 (95% CI: 0.625-0.843) based on a cutoff value of 1998.44 pg/ml; the sensitivity and specificity of this test were 80.6% and 65.6%, respectively. Furthermore, when the levels of OPG were used to distinguish the presence of MESs, the AUC was 0.766 (95% CI: 0.672-0.860); the cutoff value was 2107.91 pg/ml. The sensitivity of this cutoff value was 68.8% and the specificity was 73.7%., Conclusions: Plasma OPG levels correlate with stroke severity and the occurrence of MESs.

Background: Endovascular thrombectomy (EVT) has shown efficacy in acute ischemic stroke (AIS) patients with infective endocarditis (IE). The possibility to undertake advanced histopathological clot analysis following EVT offers a new avenue to establish the etiological basis of the stroke - which is often labelled "cryptogenic." In this paper, we present our findings from four consecutive patients with IE who underwent EVT following an AIS at our tertiary referral comprehensive stroke centre., Methods: Comprehensive histopathological analysis of clot retrieved after EVT, including morphology, was undertaken., Results: The consistent observation was the presence of dense paucicellular fibrinoid material mixed/interspersed with clusters of bacterial cocci. This clot morphology may be specific to septic embolus due to IE unlike incidental bacteraemia and could possibly explain the refractoriness of such clots to systemic thrombolysis., Conclusion: Detailed morphological and histopathological analysis of EVT-retrieved clots including Gram staining can assist in etiological classification of the clot. Understanding the composition of the clot may be of clinical value in early diagnostics and mapping treatment planning in IE.

Objective: Ischaemic brain lesions and brain abscesses are frequent in both human and animal cases of septic embolic stroke. However, existing models of brain infection do not reflect central aspects of septic embolic stroke. Our aim was to compare septic and non-septic embolic stroke in order to identify gene expressions, inflammatory mediators and brain damage in a rat model., Methods: We created precisely located focal brain infarcts in a rat model of Staphylococcus aureus infected embolic stroke. To cause septic embolic stroke we used a fibrin-rich embolus with bacteria, while every rat in the control group received a non-infected embolus. 64 rats were randomized to receive sham-surgery, sterile embolic stroke or septic embolic stroke. All groups were compared for brain pathology, mortality, gene expressions and inflammatory mediators using histology and reverse transcription quantitative real-time PCR., Results: Although infarct volumes did not differ, septic embolic stroke caused higher mortality than sterile embolic stroke (p=  0.002). Brain abscesses were observed only in the septic group. Approximately 400-500 fold increases were observed for Orm1 and Cxcl2 respectively (1.00E-08 < p < 1.92E-07) in the septic group compared to the sterile group, and these were the most dramatically regulated genes in septic embolic stroke compared to sterile embolic stroke., Conclusions: Septic embolic stroke caused brain abscesses, increased mortality and upregulated Orm1 and Cxcl2 gene expressions compared to non-infected embolic stroke. The dramatic Orm1 increase observed in the septic group is unprecedented and suggests a significant biological role of Orm1 during septic neuroinflammation.

We describe a patient-specific simulation based investigation on the role of Circle of Willis anatomy in cardioembolic stroke. Our simulation framework consists of medical image-driven modeling of patient anatomy including the Circle, 3D blood flow simulation through patient vasculature, embolus transport modeling using a discrete particle dynamics technique, and a sampling based approach to incorporate parametric variations. A total of 24 (four patients and six Circle anatomies including the complete Circle) models were considered, with cardiogenic emboli of varying sizes and compositions released virtually and tracked to compute distribution to the brain. The results establish that Circle anatomical variations significantly influence embolus distribution to the six major cerebral arteries. Embolus distribution to MCA territory is found to be least sensitive to the influence of anatomical variations. For varying Circle topologies, differences in flow through cervical vasculature are observed. This incoming flow is recruited differently across the communicating arteries of the Circle for varying anastomoses. Emboli interact with the routed flow, and can undergo significant traversal across the Circle arterial segments, depending upon their inertia and density ratio with respect to blood. This interaction drives the underlying biomechanics of embolus transport across the Circle, explaining how Circle anatomy influences embolism risk.

Stroke is a major cause of mortality and morbidity around the world. Microembolic signals (MES), as the markers of unstable atherosclerotic plaque, can predict the occurrence and prognosis of ischemic stroke (IS). MES can also assess the efficacy of antithrombotic agents and predict the recurrence probability of IS. Unstable plaques are the main source of MES; thus, numerous biomarkers of atherosclerotic plaque instability are highly likely to predict the presence of MES. This study aims to review recent biomarker candidates for MES or microembolism. Current research indicates that the following are independent markers for positive MES: high level of serum soluble P-selectin, chemokine (C-X-C motif) ligand 16 (CXCL16) and fibrinogen, high neutrophil count, reduced ratio of CD4+CD25 high regulatory T cells (Tregs) and the C allele of tumor necrosis factor receptor superfamily member 11B (TNFRSF11B) rs3102735. However, a more integrated profile of biomarkers for MES is needed to improve the stratification of patients with carotid stenosis and enhance the effectiveness of therapeutic interventions and prevention for IS., (Copyright © 2017 Elsevier B.V. All rights reserved.)

It has been reported that restriction of reperfusion after thrombolytic therapy in ischemic stroke may reduce tissue plasminogen activator (tPA) adverse effects and extend its time window. We examined whether shortIt has been reported that restriction of reperfusion after thrombolytic therapy in ischemic stroke may reduce tissue plasminogen activator (tPA) adverse effects and extend its time window. We examined whether short-term and mild local brain cooling can prevent hyperemia and/or adverse effects of delayed tPA in rat embolic stroke model. Male animals were subjected to embolic stroke and then randomly classified into control (saline), tPA (1mg/kg; i.v.), local hypothermia (LH), and tPA+LH. The drug was injected at 6 h after ischemia. LH was conducted by direct ipsilateral (injured) hemisphere cooling at 6.5h after stroke and maintained for approximately 30min. Cerebral blood flow was monitored in duration of 60 minute after tPA administration and hyperemic response was measured. Infarct volume, blood-brain barrier (BBB) disruption, edema formation, neurological deficits, and matrix metalloproteinase-9 (MMP-9) level were measured 48 h later. A combination of tPA+LH significantly diminished infarct volume in comparison with the tPA (P< 0.001) and control (P<0.05) groups. Combination therapy also decreased BBB leakage (P<0.001), MMP-9 level or edema (P<0.05) and improved neurological functions at 24 and 48h after stroke. LH caused a gradual decrease in hyperemic response after thrombolysis compared to the control (P<0.05) or tPA (P<0.001) groups. LH alone also reduced infarct volume, BBB leakage or edema (P<0.05). The short-term local brain hypothermia may mitigate reperfusion injury following delayed tPA therapy and extend its time window up to 6h., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: Thrombus composition has been suggested to have a decisive impact on the outcome of patients treated by mechanical thrombectomy because of embolic stroke. The recent development of stent retrievers allows collection and, hence, histopathological analysis of fresh thrombus material. Against this background, the aim of this prospective study was to assess the impact of thrombus composition on mechanical recanalization, clinical outcome and stroke etiology., Methods: Thirty-four patients suffering from acute ischemic stroke due to occlusion of the distal internal carotid artery/carotid-T, anterior cerebral artery, or middle cerebral arteries were mechanically recanalized, and thrombus material was obtained. Histological thrombus composition was compared with imaging, clinical, and neurointerventional data., Results: The main findings were that a higher percentage of white blood cells (WBCs) in the thrombus was associated with (i) cardioembolic etiology, (ii) extended mechanical recanalization time, and (iii) less favorable recanalization (Thrombolysis in Cerebral Infarction score) and clinical outcome (National Institute of Health Stroke Scale)., Conclusion: Our results suggest that thrombi with a high WBC fraction are related to more organized thrombi of cardioembolic origin associated with less favorable recanalization and clinical outcome in acute ischemic anterior circulation stroke. WBC-mediated immunological and coagulatory processes may play a key role in thrombus formation and pathogenesis of stroke warranting further investigation.

We describe a 59-year-old stroke patient presented with sudden onset left side weakness and a speech disorder due to a major acute cerebral infarction in the area of the right middle cerebral artery, right posterior cerebral artery, and small infarctions in the area of the left middle and left posterior cerebral artery. For the previous month, the patient had been feeling weak and had no appetite. The patient had not been previously seriously ill. A chest x-ray showed a large mass in the upper zone of the right lung. Chest computed tomography scan and echocardiography were performed and revealed advanced lung cancer invading the left atrium. Spontaneous tumor embolism is a rare cause of stroke and should be considered in the differential diagnosis of stroke in a cancer patient. Also, sometimes stroke can be the first manifestation of advanced cancer., (Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background: We previously demonstrated that tissue plasminogen activator (tPA) reduces infarct size after mechanical middle cerebral artery occlusion (MCAO) in wild-type (WT) mice and transgenic mice expressing human leukocyte antigen DR2 (DR2-Tg). Clinically, tPA limits ischemic damage by dissolving the clot blocking blood flow through a cerebral artery. To mimic the clinical situation, we developed a new mouse model of thromboembolic stroke, and tested the efficacy of tPA in WT and DR2-Tg mice. New Method Autologous blood is withdrawn into a PE-8 catheter filled with 2 IU α-thrombin. After exposing the catheter briefly to air, the catheter is reintroduced into the external (ECA) and advanced into the internal carotid artery (ICA) to allow for intravascular injection of thrombin at the MCA bifurcation. To validate the model, we tested the effect of tPA on laser-Doppler perfusion (LDP) over the MCA territory and infarct size in WT and DR2-Tg mice., Results: The procedure results in a consistent drop in LDP, and leads to a highly reproducible ischemic lesion. When administered at 15min after thrombosis, tPA restored LDP and resulted in a significant reduction in infarct size at 24h after thrombosis in both WT and DR2-Tg., Comparison With Existing Methods: Our model significantly reduces surgery time, requires a single anesthesia exposure, and produces a consistent and predictable infarction, with low variability and mortality., Conclusion: We validated the efficacy of tPA in restoring blood flow and reducing infarct in a new model of endovascular thromboembolic stroke in the mouse., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background and Purpose: It is unclear whether clot composition analysis is helpful to predict a stroke mechanism in acute large vessel occlusion. In addition, the relationship between early vessel signs on imaging studies and clot compositions has been poorly understood. The purpose of this study was to elucidate the relationship between clot composition and stroke etiology following mechanical thrombectomy and to investigate the effect of varied clot compositions on gradient-echo MR imaging of clots., Materials and Methods: Histopathologic analysis of retrieved clots from 37 patients with acute MCA occlusion was performed. Patients underwent gradient-echo imaging before endovascular therapy. Retrieved clots underwent semiquantitative proportion analysis to quantify red blood cells, fibrin, platelets, and white blood cells by area. Correlations between clot compositions and stroke subtypes and susceptibility vessel signs on gradient-echo imaging were assessed., Results: Stroke etiology was classified as cardioembolism in 22 patients (59.4%), large-artery atherosclerosis in 8 (21.6%), and undetermined in 7 (18.9%). The clots from cardioembolism had a significantly higher proportion of red blood cells (37.8% versus 16.9%, P = .031) and a lower proportion of fibrin (32.3% versus 48.5%, P = .044) compared with those from large-artery atherosclerosis. The proportion of red blood cells was significantly higher in clots with a susceptibility vessel sign than in those without it (48.0% versus 1.9%, P < .001), whereas the proportions of fibrin (26.4% versus 57.0%, P < .001) and platelets (22.6% versus 36.9%, P = .011) were significantly higher in clots without a susceptibility vessel sign than those with it., Conclusions: The histologic composition of clots retrieved from cerebral arteries in patients with acute stroke differs between those with cardioembolism and large-artery atherosclerosis. In addition, a susceptibility vessel sign on gradient-echo imaging is strongly associated with a high proportion of red blood cells and a low proportion of fibrin and platelets in retrieved clots., (© 2015 by American Journal of Neuroradiology.)

Background and Purpose: Dual-energy CT features the opportunity to differentiate among up to 3 different materials because the absorption of x-rays depends on the applied tube voltage and the atomic number of the material. For example, it is possible to distinguish between blood-brain barrier disruption and an intracerebral hemorrhage following treatment for a stroke. The aim of this study was to evaluate whether dual-energy CT is capable of distinguishing intra-arterial contrast agent from residually clotted vessels immediately after endovascular stroke therapy., Materials and Methods: Sixteen patients (9 women, 7 men; mean age, 63.6 ± 13.09 years) were examined. Measurements were made on the postinterventional dual-energy CT virtual noncontrast, iodine map, and "weighted" brain window (weighted dual-energy) series. Postinterventional conventional angiography was used as the criterion standard method., Results: A residual clot was found in 10 patients. On the virtual noncontrast series, the Hounsfield attenuation of the clotted arteries was higher than that in the corresponding perfused contralateral arteries (53.72 ± 9.42 HU versus 41.64 ± 7.87 HU; P < .05). The latter had higher absorption values on the weighted dual-energy series than on the virtual noncontrast series (49.37 ± 7.44 HU versus 41.64 ± 7.87 HU; P < .05). The sensitivity for the detection of a residual clot was 90%; the specificity was 83.3%, and the accuracy was 87.5%. Interrater agreement was good (κ = 0.733)., Conclusions: Dual-energy CT may be valuable in the detection of clot persistence or early re-thrombosis without the necessity of additional contrast administration. However, its relevance for the prediction of outcomes remains to be determined in further studies., (© 2015 by American Journal of Neuroradiology.)

Background: Previous studies have reported that the total bilirubin (TB) level is associated with coronary artery disease, heart failure and atrial fibrillation. These heart diseases can produce cardiogenic cerebral embolism and cause cardioembolic stroke. However, whether the serum TB could be a biomarker to differentiate cardioembolic stroke from other stroke subtypes is unclear., Methods: Our study consisted of 628 consecutive patients with ischaemic stroke. Various clinical and laboratory variables of the patients were analysed according to serum TB quartiles and stroke subtypes., Results: The higher TB quartile group was associated with atrial fibrillation, larger left atrium diameter, lower left ventricular fractional shortening and cardioembolic stroke (P < 0.001, P = 0.001, P = 0.033, P < 0.001, respectively). Furthermore, serum TB was a statistically significant independent predictor of cardioembolic stroke in a multivariable setting (Continuous, per unit increase OR = 1.091, 95%CI: 1.023-1.164, P = 0.008)., Conclusions: Serum TB level was independently associated with cardioembolic stroke. The combination of clinical data and serum TB may be a feasible strategy to diagnose cardioembolic stroke in the acute phase.

Introduction: Undetermined strokes with an embolic pattern (USEP) represent a common phenotype. We assessed their frequency and compared USEP with cardioembolic stroke with a known source and non-cardioembolic stroke etiology., Methods: Study patients were 540 consecutive ischemic stroke patients admitted to Helsinki University Hospital with primary end-point of recurrent stroke in a 21-month follow-up. Cox regression adjusting for CHA2DS2-VASc and anticoagulation estimated the risk of USEP on recurrent stroke., Results: A total of 229 (42.4%) patients had a non-cardioembolic stroke etiology, 184 (34.1%) had a cardioembolic stroke with a known source, and 127 (23.5%) were classified as USEP. USEP patients had less diabetes and prior TIA, with more severe symptoms than the non-cardioembolic stroke cases. They were younger, had fewer comorbidities, and less severe symptoms than the cardioembolic stroke patients. Cumulative risk of recurrent stroke was 10.0% (95% CI 4.1%-15.9%) for USEP, 5.0% (1.1%-8.9%) for cardioembolic strokes, and 5.0% (3.0%-7.0%) for non- cardioembolic strokes (P = 0.089). USEP associated with a higher risk of recurrent stroke compared to non-cardioembolic strokes (hazard ratio 2.36, 95% CI 1.02-5.47; P = 0.046) and cardioembolic stroke with a known source (1.83, 1.07-3.14; P = 0.028)., Conclusions: Despite their younger age and more favorable risk factor profile compared with other phenotypes, USEP exhibited a high risk of stroke recurrence.

Background: The incidence of depression and anxiety disorders is twice as high in women than men; however, females exhibit less neuronal damage following an equivalent ischemic event. Microembolic stroke increases anxiety- and depressive-like behaviors in male rats but the behavioral repercussions in females are unknown., Findings: Given the relative neuronal protection from stroke in ovary-intact females, female rats exposed to microembolic stroke may be behaviorally protected as compared to males. The data presented demonstrate that anxiety-like behavior is increased in males despite a comparable increase in microglial activation following microembolic stroke in both males and females., Conclusions: These data suggest that males may be more behaviorally susceptible to the effects of microembolic stroke and further illustrate a dissociation between neuroinflammation and behavior in females.

Cerebral blood flow (CBF) and blood-brain barrier (BBB) permeability by arterial spin labeling (ASL)- and dynamic contrast enhanced (DCE)-magnetic resonance imaging (MRI), respectively were repeatedly measured under either halothane (N  =  5) or isoflurane (N  =  5) anesthesia in a rat stroke model of embolic occlusion of middle cerebral artery (MCA). Cerebral blood flow measurements were made after MCA embolization, following intravenous recombinant tissue plasminogen activator (rtPA) treatment at 3 hours post-ictus and again at 48 hours. Blood-brain barrier opening was examined after rtPA infusion and again at 48 hours. Data were analyzed using paired t-tests and significance considered at P < 0·05. The extent and magnitude of CBF reduction due to stroke did not differ between the two groups. Blood-to-brain forward rate constant, K(trans), a measure of BBB permeability, for an MRI contrast agent gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA), was elevated in the ipsilateral hemisphere in both cohorts. However, isoflurane-anesthetized rats exhibited a trend of lower K(trans) values at 48 hours (P  =  0·06) indicating reduced BBB damage in the ipsilateral hemisphere. The area of BBB opening followed a similar trend with the isoflurane-anesthetized group exhibiting a smaller area of BBB damage acutely and at 48 hours compared to the halothane-anesthetized group.

Background: Fat embolism syndrome is a life-threatening condition with treatment centering on the provision of excellent supportive care and early fracture fixation. No pharmacologic intervention has yet shown any clear benefit. We used high-dose rosuvastatin specifically for its anti-inflammatory effects to treat a patient with severe fat embolism syndrome. We also suggest that magnetic resonance imaging and transcranial Doppler studies are helpful in establishing the diagnosis and for monitoring the patient's course., Patient: A 17-year-old boy developed severe cerebral fat embolism syndrome with multifocal strokes after sustaining bilateral femur fractures., Results: In spite of profound and prolonged neurological impairment, our patient experienced dramatic recovery by the time he was discharged from inpatient rehabilitation several weeks after his initial injury. Magnetic resonance imaging revealed the classic "starfield" pattern of infarcts on diffusion-weighted sequences early in the illness. Additionally, serial transcranial Doppler studies demonstrated dramatically elevated microembolic events that resolved completely during the course of treatment., Conclusion: We feel that the acute administration of high-dose rosuvastatin early in the development of our patient's illness may have contributed to his ultimate recovery. Therapeutic guidelines cannot be extrapolated from a single patient, but our experience suggests that statin therapy could be potentially beneficial for individuals with severe fat embolism syndrome, and this approach deserves further clinical evaluation. Additionally, the diagnosis and monitoring of cerebral involvement in fat embolism syndrome is facilitated by both magnetic resonance imaging and transcranial Doppler studies., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background and Purpose: Calcified cerebral emboli are a rarely reported but devastating cause of stroke and may be the first manifestation of vascular or cardiac disease. Our aim was to evaluate the diagnosis, prevalence, imaging appearance, presumed embolic source, treatment, and outcome of patients with calcified cerebral emboli., Materials and Methods: Our radiology information system was searched for all CT scans by using keywords "calcified," "emboli," and their permutations. The radiology information system was also searched to identify all "stroke" CT reports to calculate the prevalence of calcified cerebral emboli. We also performed a MEDLINE search to identify all published case reports., Results: Twenty-two cases were identified from our database, and 48 were cases reported from the literature. The middle cerebral artery was the site of 83% of calcified emboli. Presumed sources were calcific aortic stenosis (36%), carotid atherosclerotic plaque (30%), and mitral annular calcification (11%). Spontaneous embolism occurred in 86%. Surgical treatment was performed in 34% of patients. Sixty-four percent of the patients with calcified aortic stenosis underwent aortic valve replacement. Among those with identifiable arterial disease, 53% underwent endarterectomy. Forty-one percent of patients experienced at least 1 recurrent stroke. The prevalence of calcified cerebral emboli identified on stroke CT scans at our institution was 2.7%. Seventy-three percent of cases were correctly identified. Twenty-seven percent were misdiagnosed on initial interpretation, while 9% were overlooked on preliminary interpretation., Conclusions: Calcified cerebral emboli are more common than previously assumed, are frequently overlooked or misinterpreted, affect clinical course when diagnosed, and carry substantial risk for recurrent stroke., (© 2014 by American Journal of Neuroradiology.)

Finding an efficient neuroprotectant is of urgent need in the field of stroke research. The goal of this study was to test the effect of acute simvastatin administration after stroke in a rat embolic model and to explore its mechanism of action through brain proteomics. To that end, male Wistar rats were subjected to a Middle Cerebral Arteria Occlusion and simvastatin (20 mg/kg s.c) (n = 11) or vehicle (n = 9) were administered 15 min after. To evaluate the neuroprotective mechanisms of simvastatin, brain homogenates after 48 h were analyzed by two-dimensional fluorescence Difference in Gel Electrophoresis (DIGE) technology. We confirmed that simvastatin reduced the infarct volume and improved neurological impairment at 48 h after the stroke in this model. Considering our proteomics analysis, 66 spots, which revealed significant differences between groups, were analyzed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry allowing the identification of 27 proteins. From these results, we suggest that simvastatin protective effect can be partly explained by the attenuation of the oxidative and stress response at blood-brain barrier level after cerebral ischemia. Interestingly, analyzing one of the proteins (HSP75) in plasma from stroke patients who had received simvastatin during the acute phase, we confirmed the results found in the pre-clinical model. Our aim was to study statins benefits when administered during the acute phase of stroke and to explore its mechanisms of action through brain proteomics assay. Using an embolic model, simvastatin-treated rats showed significant infarct volume reduction and neurological improvement compared to vehicle-treated group. Analyzing their homogenated brains by two-dimensional fluorescence Difference in Gel Electrophoresis (DIGE) technology, we concluded that the protective effect of simvastatin can be attributable to oxidative stress response attenuation and blood-brain barrier protection after cerebral ischemia., (© 2014 International Society for Neurochemistry.)

Background: The presence or absence of the penumbra area is important when performing reperfusion therapy in patients with acute ischemic stroke. As a predictor of this penumbra area, magnetic resonance angiography (MRA)-diffusion-weighted imaging (DWI) mismatch is attracting attention. The usefulness of MRA-DWI mismatch (MDM) using the DWI-Alberta Stroke Program Early Computed Tomography Score (ASPECTS) in endovascular treatment (EVT) of patients with cerebral large vessel occlusion was evaluated., Methods: Of 1442 patients registered in the Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Registry between July 1, 2010 and June 30, 2011 who presented to the hospital within 24 hours of the onset of acute cerebral infarction because of cerebral large vessel occlusion, 188 patients who had internal carotid artery or middle cerebral artery occlusion and achieved recanalization with EVT were included. Of these, 71 patients underwent intracranial EVT because intravenous recombinant tissue plasminogen activator therapy was ineffective. The associations between the presence or absence of MDM (MDM-positive [MDM-P], DWI-ASPECTS≥6; MDM-negative [MDM-N], DWI-ASPECTS<6) and 90-day prognosis (modified Rankin Scale [mRS]) and symptomatic intracranial hemorrhage (sICH) were examined., Results: Of the 188 patients analyzed, the time from symptom onset to admission was within 3 hours in 143 patients, 3-8 hours in 36 patients, and 8 hours or more in 9 patients. The time from the onset was within 3 hours in 118 patients in the MDM-P and 25 patients in the MDM-N cases. Favorable outcomes (mRS score≤2 at 90 days) were seen in 63 patients (53.4%) in the MDM-P group and 7 patients (28.0%) in the MDM-N group, showing a significantly more favorable clinical outcome in the MDM-P group (P=.027). The incidence of sICH was significantly lower in the MDM-P group (MDM-P group 3.4%, MDM-P group 20.0%; P=.009). The time from the onset was 3-8 hours in 29 patients in the MDM-P group and in 7 patients in the MDM-N group. Favorable outcomes were seen in 12 patients (41.4%) in the MDM-P group and 2 patients (28.6%) in the MDM-N group, with no significant difference between the 2 groups. No patients had sICH. The patients admitted 8 hours or more after the onset were all MDM-P. Five patients (55.6%) had a favorable outcome., Conclusions: This study demonstrated the safety and efficacy of EVT in MDM-P patients within 3 hours of symptom onset. Although the ratio of patients who had a favorable outcome was high in the MDM-P patients admitted 3-8 hours after the onset, the difference was not significant., (Copyright © 2014 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

We report the case of a 27-year-old man with a history of previously undiagnosed renal disease that presented with multiple cerebrovascular infarctions. Workup for traditional causes of cerebrovascular infarction including cardiac telemetry, multiple echocardiograms, and hypercoagulative workup was negative. However, a transcranial Doppler detected circulating microemboli at the rate of 14 per hour. A serum oxalate level greater than the supersaturation point of calcium oxalate was detected, providing a potential source of the microemboli. Furthermore, serial imaging recorded rapid mineralization of the infarcted territories. In the absence of any proximal vessel irregularities, atherosclerosis, valvular abnormalities, arrhythmias, or systemic shunt as potential stroke etiology in this patient, we propose that circulating oxalate precipitate may be a potential mechanism for stroke in patients with primary oxalosis., (Copyright © 2013 by the American Society of Neuroimaging No claim to original US government works.)

Purpose: To compare magnetic resonance imaging (MRI) brain feature in cryptogenic stroke patients with patent foramen ovale (PFO), cryptogenic stroke patients without PFO and patients with cardioembolic stroke., Materials and Methods: The ethics committee required neither institutional review board approval nor informed patient consent for retrospective analyses of the patients' medical records and imaging data. The patients' medical files were retrospectively reviewed in accordance with human subject research protocols. Ninety-two patients under 60 years of age were included: 15 with cardioembolic stroke, 32 with cryptogenic stroke with PFO and 45 with cryptogenic stroke without PFO. Diffusion-weighted imaging of brain MRI was performed by a radiologist blinded to clinical data. Univariate, Fischer's exact test for qualitative data and non-parametric Wilcoxon test for quantitative data were used., Results: There was no statistically significant difference found between MRI features of patients with PFO and those with cardioembolic stroke (p<.05). Patients without PFO present more corticosubcortical single lesions (p<.05) than patients with PFO. Patients with PFO have more often subcortical single lesions larger than 15mm, involvement of posterior cerebral arterial territory and intracranial occlusion (p<.05) than patients with cryptogenic stroke without PFO., Conclusion: Our study suggests a cardioembolic mechanism in ischemic stroke with PFO., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background and Purpose: N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP), an endogenously produced circulating peptide in humans and rodents, exerts anti-inflammatory and cardioprotective activities in various cardiovascular diseases., Methods: The present study evaluated the neuroprotective effect of AcSDKP alone and in combination with thrombolytic therapy in a rat model of embolic focal cerebral ischemia., Results: We found that treatment with AcSDKP alone at 1 hour or the combination treatment with AcSDKP and tissue plasminogen activator (tPA) at 4 hours after stroke onset substantially increased AcSDKP levels in plasma and cerebrospinal fluid and robustly reduced infarct volume and neurological deficits, without increasing the incidence of brain hemorrhage compared with ischemic rats treated with saline, AcSDKP alone at 4 hours, and tPA alone at 4 hours. Moreover, the combination treatment considerably reduced the density of nuclear transcription factor-κB (NF-κB), transforming growth factor β (TGF-β), and plasminogen activator inhibitor-1 (PAI-1) positive cerebral blood vessels in the ischemic brain, all of which were associated with reduced microvascular fibrin extravasation and platelet accumulation compared with tPA monotherapy. In vitro, AcSDKP blocked fibrin-elevated TGF-β1, PAI-1, and NF-κB proteins in primary human brain microvascular endothelial cells., Conclusions: Our data indicate that AcSDKP passes the blood-brain barrier, and that treatment of acute stroke with AcSDKP either alone at 1 hour or in combination with tPA at 4 hours of the onset of stroke is effective to reduce ischemic cell damage in a rat model of embolic stroke. Inactivation of TGF-β and NF-κB signaling by AcSDKP in the neurovascular unit may underlie the neuroprotective effect of AcSDKP.

Objective: Cerebral protection device utilization during carotid artery stenting (CAS) has been shown to decrease risk of perioperative stroke. The two most commonly used devices are distal filters and proximal protection devices, which allow blood flow cessation or flow reversal. The goal of the present study was to examine anatomic and morphologic characteristics of the treated lesions using each type of cerebral protection device and compare clinical 30-day adverse event rates between the two cerebral protection groups., Methods: We conducted a single-center, retrospective review of consecutive CAS cases with proximal protection devices that were matched with CAS cases using distal filter protection devices based on indication (symptomatic vs. asymptomatic), age, and gender. We reviewed clinical, anatomic, and morphologic characteristics of the stented lesions in cases of proximal or distal protection and also studied the rate of major adverse events within the first 30 days after the procedure., Results: We identified a total of 70 patients treated with proximal protection devices who were matched in a blinded fashion to 70 cases with distal protection. There was a significantly higher number of high-risk lesions in patients who had CAS using proximal protection devices (P = 0.009). There was no significant difference in overall frequency of 30-day adverse outcomes (transient ischemic attack/stroke/reperfusion hemorrhage/death) between the two groups (P = 1.0)., Conclusions: Our study is the first attempt (to our knowledge) to review and compare anatomic and morphologic characteristics of the stented lesions in cases of proximal versus distal protection for CAS. Our data indicate that in properly selected patients both approaches could be equally safe and effective., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background and Purpose: Despite a high incidence of poststroke dementia, there is no specific treatment for this condition. Because the evaluation of poststroke cognitive deficits in animal models of stroke is exceedingly challenging, the preclinical evaluation of candidate drugs is limited. We aimed to explore the impact of small cortical photothrombotic strokes on poststroke cognition, thereby assessing the suitability of this experimental stroke model for the investigation of cognitive impairment after stroke., Methods: Photothrombotic cortical infarcts were induced in 19 adult male Wistar rats. Nineteen sham-operated animals served as controls. Using the Morris water maze, we analyzed the impact of photothrombotic stroke on both the acquisition of new memories and the recall of previously acquired memories. The cylinder test, the adhesive tape removal test, and the rotarod test were performed to investigate sensorimotor deficits., Results: Photothrombotic stroke significantly impaired the recall of previously acquired memories (P<0.05), whereas the acquisition of new memories remained largely intact. The analysis of the animals' swimming speed in the water maze and the rotarod test showed no confounding motor impairments after photothrombotic stroke. The adhesive tape removal test and the cylinder test revealed mild sensorimotor deficits in lesioned animals (P<0.05)., Conclusions: Photothrombotic cortical infarcts impair the recall of memories acquired before stroke, whereas the formation of new memories remains unimpaired. The observed deficits in the water maze are not confounded by disturbed motor functions. Overall, experimental photothrombotic strokes are well suited for the investigation of specific cognitive impairments after stroke.

Cardioembolic stroke is generally caused by intracranial artery occlusion. Clots may be identified in the intracranial vessels by means of conventional neuroimaging in the acute phase. High-resolution ultrasonography may show some features suggestive of cardiac emboli when occluding extracranial carotid arteries. We describe a patient with cardioembolic ischemic stroke in the right hemisphere in whom a left internal carotid artery stenosis paradoxically protected the ipsilateral hemisphere from distal intracranial embolism. The patient also presented multiple acute ischemic embolic lesions in the right middle cerebral artery territory and in the right occipital lobe, which was fed by the posterior cerebral artery, anomally originating from the right carotid siphon. Interestingly, the left internal carotid artery--which showed a severe preexisting stenosis--was occluded by the cardiac clot, whereas the right internal carotid artery only presented a moderate stenosis that had probably allowed the clots to pass. Therefore, the severe left internal carotid artery stenosis may have blocked the cardiac embolus, preventing it from reaching the ipsilateral hemisphere., (Copyright © 2013 Wiley Periodicals, Inc., A Wiley Company.)

Intracarotid transplantation has shown potential for efficient stem cell delivery to the brain. However, reported complications, such as compromised cerebral blood flow (CBF), prompted us to perform further safety studies. Glial-restricted precursors (GRPs) and mesenchymal stem cells (MSCs) were transplanted into the internal carotid artery of rats (n=99), using a microcatheter. Magnetic resonance imaging was used to detect post-transplantation complications, including the development of stroke, for the following experimental variables: cell size, cell dose, cell infusion velocity, delay between artery occlusion and cell infusion, discordant versus concordant xenografting, and intracarotid transplantation with preserved versus compromised blood flow. Immunocompatibility and delayed infusion did not affect the number of complications. An infusion velocity over 1 mL/minute often resulted in stroke (27 out of 44 animals), even with an infusion of vehicle, whereas a lower velocity (0.2 mL/minute) was safe for the infusion of both vehicle and smaller cells (GRPs, diameter=15 μm). Infusion of larger cells (MSCs, diameter=25 μm) resulted in a profound decrease (75±17%) in CBF. Stroke lesions occurred frequently (12 out of 15 animals) when injecting 2 × 10(6) MSCs, but not after lowering the dose to 1 × 10(6) cells. The present results show that cell size and infusion velocity are critical factors in developing safe protocols for intracarotid stem cell transplantation.

Background and Purpose: The uncertain risk of secondary intracerebral hemorrhage (sICH) frequently keeps clinicians from initiating oral anticoagulation (OAC) early after ischemic cardioembolic stroke. The goal of this experimental study was to determine the risk of sICH depending on the timing of OAC initiation relative to stroke onset and to address the role of hematogenous macrophages for repair processes preventing OAC-associated sICH., Methods: C57BL/6 mice were subjected to transient middle cerebral artery occlusion. Subgroups were treated with either the vitamin K antagonist (VKA) phenprocoumon or the direct thrombin inhibitor dabigatran etexilate. Hematogenous macrophages were depleted using intraperitoneal injections of clodronate-filled liposomes., Results: Time to therapeutic OAC was 48 hours with VKA and 0.5 hours with dabigatran etexilate treatment. In VKA-treated mice, the risk of sICH was high if effective OAC was already present at stroke onset or achieved within 48 hours after ischemia. With more delayed OAC, the risk of sICH rapidly decreased. Compared with VKA treatment, effective anticoagulation with dabigatran etexilate was associated with a significantly reduced extent of sICH, either if present at stroke onset or if achieved 48 hours later. Partial depletion of macrophages greatly increased the extent of OAC-associated sICH in the subacute stage of 3 to 4 days after ischemia., Conclusions: Our findings suggest that repair mechanisms involving hematogenous macrophages rapidly decrease the risk of OAC-associated sICH in the first days after ischemic stroke. The lower risk of sICH under dabigatran etexilate compared with VKA treatment may facilitate early initiation of OAC after cardioembolic stroke.

Background and Purpose: The aim of this study was to investigate differences in risk factors and stroke mechanisms between intracranial atherosclerosis (ICAS) and extracranial atherosclerosis (ECAS) and between anterior and posterior circulation atherosclerosis., Methods: A multicenter, prospective, Web-based registry was performed on atherosclerotic strokes using diffusionweighted magnetic resonance imaging and magnetic resonance angiography. Stroke mechanisms were categorized as artery-to-artery embolism, in situ thrombo-occlusion, local branch occlusion, or hemodynamic impairment., Results: Onethousand patients were enrolled from 9 university hospitals. Age (odds ratio [OR], 1.033; 95% confidence interval [CI], 1.018-1.049), male gender (OR, 3.399; 95% CI, 2.335-4.949), and hyperlipidemia (OR, 1.502; 95% CI, 1.117-2.018) were factors favoring ECAS (vs ICAS), whereas hypertension (OR, 1.826; 95% CI, 1.274-2.618; P=0.001) and diabetes mellitus (OR, 1.490; 95% CI, 1.105-2.010; P=0.009) were related to posterior (vs anterior) circulation diseases. Metabolic syndrome was a factor related to ICAS (vs ECAS) only in posterior circulation strokes (OR, 2.433; 95% CI, 1.005-5.890; P=0.007). Stroke mechanisms included arterytoartery embolism (59.7%), local branch occlusion (14.9%), in situ thrombo-occlusion (13.7%), hemodynamic impairment (0.9%), and mixed (10.8%). Anterior ICAS was more often associated with artery-to-artery embolism (51.8% vs 34.0%) and less often associated with local branch occlusion (12.3% vs 40.4%) than posterior ICAS (P<0.001)., Conclusions: The prevalence of risk factors and stroke mechanisms differ between ICAS and ECAS, and between anterior and posterior circulation atherosclerosis. Posterior ICAS seems to be closely associated with metabolic derangement and local branch occlusion. Prevention and management strategies may have to consider these differences.

Background and Purpose: Tissue plasminogen activator (tPA) is the only approved therapy for acute ischemic stroke. However, tPA has a brief therapeutic window. Its side effects include intracerebral bleeding and neurotoxicity. Therefore, a combination therapy with tPA and agents that can extend the therapeutic window of tPA and/or counteract its side effects are warranted. Here, we studied whether 3K3A-APC, a neuroprotective analog of activated protein C with reduced anticoagulant activity, can enhance the therapeutic effects of tPA in models of ischemic stroke in rodents., Methods: Human recombinant tPA (10 mg/kg), alone or in combination with human recombinant 3K3A-APC (2 mg/kg), was administered intravenously 4 hours after proximal or distal transient middle cerebral artery occlusion in mice and embolic stroke in rats. The 3K3A-APC was additionally administered for 3 to 4 consecutive days after stroke. The neuropathological and neurological analyses were performed at 1 to 7 days after stroke., Results: In all models, tPA alone had no effects on the infarct volume or behavior (ie, neurological score, foot-fault, forelimb asymmetry, adhesive removal) compared with vehicle. The tPA and 3K3A-APC combination therapy reduced the infarct volume 24 hours and 7 days after proximal or distal transient middle cerebral artery occlusion in mice and 7 days after embolic stroke in rats by 65%, 63%, and 52%, respectively, significantly (P<0.05) improved behavior and eliminated tPA-induced intracerebral microhemorrhages., Conclusions: The 3K3A-APC extends the therapeutic window of tPA for ischemic stroke in rodents. Therefore, this combination therapy also should be considered for treating stroke in humans.

Inflammation following ischaemic stroke attracts high priority in current research, particularly using human-like models and long-term observation periods considering translational aspects. The present study aimed on the spatio-temporal course of macrophage-like cell accumulation after experimental thromboembolic stroke and addressed microglial and astroglial reactions in the ischaemic border zone. Further, effects of tissue plasminogen activator (tPA) as currently best treatment for stroke and the potentially neuroprotective co-administration of hyperbaric oxygen (HBO) were investigated. Rats underwent middle cerebral artery occlusion and were assigned to control, tPA or tPA+HBO. Twenty-four hours, 7, 14 and 28 days were determined as observation time points. The accumulation of macrophage-like cells was semiquantitatively assessed by CD68 staining in the ischaemic area and ischaemic border zone, and linked to the clinical course. CD11b, ionized calcium binding adaptor molecule 1 (Iba), glial fibrillary acidic protein (GFAP) and Neuronal Nuclei (NeuN) were applied to reveal delayed glial and neuronal alterations. In all groups, the accumulation of macrophage-like cells increased distinctly from 24 hours to 7 days post ischaemia. tPA+HBO tended to decrease macrophage-like cell accumulation at day 14 and 28. Overall, a trend towards an association of increased accumulation and pronounced reduction of the neurological deficit was found. Concerning delayed inflammatory reactions, an activation of microglia and astrocytes with co-occurring neuronal loss was observed on day 28. Thereby, astrogliosis was found circularly in contrast to microglial activation directly in the ischaemic area. This study supports previous data on long-lasting inflammatory processes following experimental stroke, and additionally provides region-specific details on glial reactions. The tendency towards a decreasing macrophage-like cell accumulation after tPA+HBO needs to be discussed critically since neuroprotective properties were recently ascribed to long-term inflammatory processes.

Several case reports and studies suggest that partially thrombosed large and giant aneurysms are potential sources of distal embolic events. However, there are limited data on small thrombosed aneurysms as a possible cause of ischemic events. Three patients are reported who presented with acute ischemic stroke and in whom the initial imaging studies showed a small (<10 mm), unruptured, partially thrombosed aneurysm. In each case, the aneurysm location was confirmed by a conventional angiogram. In all cases, the aneurysms were found on the proximal middle cerebral artery, in the territory corresponding to the clinical symptoms of the stroke. The mechanism of middle cerebral artery embolic event was thought to be related to the thrombus within the aneurysm, causing subsequent embolization into distal related vascular territory. Two of these patients had craniotomy for aneurysm clipping; one was managed conservatively with medical therapy alone. Thrombosis of small, unruptured intracranial aneurysms should be considered as a possible cause of acute-onset stroke symptoms in patients with acute ischemic stroke. It is under-recognized in the current literature, and no guidelines currently exist for medical or surgical treatment of such aneurysms. Medical management is often decided on an individual basis. Surgical treatment mostly involves aneurysmal clipping rather than coiling.

Introduction: Transcatheter arterial chemoembolization (TACE) is a widely used form of therapy in advanced hepatocellular carcinoma. We report the first pathological data from an autopsy case of multiple cerebral emboli occurring during TACE., Methods: A Medline search for previous cases of cerebral embolism and TACE revealed 11 other cases., Findings: Multiple microscopic subacute infarcts were found in the cerebrum, midbrain, and cerebellum of our patient on autopsy, but no embolic material was seen. Embolic material was noted in dilated vessels throughout the fibrotic right diaphragm and in the upper lobe of the right lung. Combining the literature search with our patient, the mortality of cerebral embolism after TACE is 25% (n = 12). Intracardiac shunts were seen in 20% of the cases (n = 10). Hyperdense lesions were seen on head CT in 80% of the patients evaluated (n = 10). Chest imaging revealed infiltrate or consolidation in 60% of the cases (n = 5). Pulmonary emboli were reported in 100% of the cases (n = 8)., Conclusions: Cerebral embolism after TACE is devastating. Brain pathology supports embolization of ethiodized oil rather than DC beads as the mechanism of cerebral injury. Further pathological studies are needed to better understand the pathophysiology of this condition. Lung pathology confirmed the presence of embolic material in the distal lung, suggestive of a hepatopulmonary shunt undetectable by current modalities. Evaluation for such shunts with emerging modalities such as TCD with emboli detection may be an area of future research., (Copyright © 2012 National Stroke Association. Published by Elsevier Inc. All rights reserved.)

Background: Although the mechanism of migraine is regarded as a functional disorder of the brain, numerous studies have reported that migraine is closely associated with vascular system abnormalities., Case Reports: We describe a 19-year-old female with recurrent migraine attacks and typical aura for 7 years. MRI showed multiple stroke lesions in the posterior circulation. Moreover, a pseudoaneurysm (1.9 × 1.4 cm) originating from the left vertebral artery was observed on four-vessel angiography. Multiple microembolic signals (MES) were repeatedly observed in the basilar artery using 30-minute transcranial Doppler monitoring. Interestingly, MES and her typical migrainous symptoms disappeared simultaneously with removal of the pseudoaneurysm., Discussion: This case supports the fact that microemboli play a pivotal role in the development of migraine attacks.

Background and Purpose: Silent brain infarctions are associated with an increased risk of stroke in healthy individuals. Risk of recurrent stroke in patients with both symptomatic and silent brain infarction (SBI) has only been investigated in patients with cardioembolic stroke in the European Atrial Fibrillation Trial. We assessed whether patients with recent noncardioembolic stroke and SBI detected on MRI are at increased risk for recurrent stroke, other cardiovascular events, and mortality., Methods: The prevalence of SBI detected on MRI was assessed in 1014 patients enrolled in the imaging substudy of the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial. The primary outcome was first recurrence of stroke in patients with both symptomatic stroke and SBI in comparison with age- and sex-matched patients with stroke without SBI. Secondary outcomes were a combined vascular end point, other vascular events, and mortality. The 2 groups were compared using conditional logistic regression., Results: Silent brain infarction was detected in 207 (20.4%) of the 1014 patients. Twenty-seven (13.0%) patients with SBI and 19 (9.2%) without SBI had a recurrent stroke (OR, 1.42; 95% CI, 0.79-2.56; P=0.24) during a mean follow-up of 2.5 years. Similarly, there was no statistically significant difference for all secondary outcome parameters between patients with SBI and matched patients without SBI., Conclusions: The presence of SBI in patients with recent mild noncardioembolic ischemic stroke could not be shown to be an independent risk factor for recurrent stroke, other vascular events, or a higher mortality rate., Clinical Trial Registration: URL: http://clinicaltrials.gov. Unique identifier: NCT00153062.

Background and Purpose: Information on the clinical and hemodynamic profile of intravenous tissue-type plasminogen activator nonresponders, at different locations of arterial occlusion, may improve the selection of candidates for rescue reperfusion therapies. Therefore, we aim to investigate predictors of failing intravenous tissue-type plasminogen activator therapy according to occluded vessel and location of the clot., Methods: We prospectively evaluated consecutive patients with an acute ischemic stroke admitted within the first 6 hours of onset. Five hundred forty-eight patients with documented intracranial occlusion were included. Patients were categorized according to site of vessel occlusion into 4 distinct groups: proximal middle cerebral artery occlusion (n=251), distal middle cerebral artery occlusion (n=194), internal carotid artery bifurcation occlusion (n=61), and basilar artery occlusion (n=42). Recanalization was assessed on transcranial Doppler at 1 hour of tissue-type plasminogen activator bolus., Results: Among patients with proximal middle cerebral artery occlusion, the presence of severe extracranial internal carotid artery stenosis or occlusion (OR, 2.36; 95% CI, 1.15-4.84; P=0.02) and age >74 years (OR, 1.84; 95% CI, 1.02-3.31; P=0.04) independently predicted no recanalization. No independent predictors of no recanalization were identified in patients with distal middle cerebral artery occlusion. In patients with internal carotid artery bifurcation occlusion, a previous diagnosis of hypertension (OR, 12.77; 95% CI, 2.12-76.88; P=0.05), and absence of atrial fibrillation (OR, 8.15; 95% CI, 1.40-47.44; P=0.02) emerged as independent predictors of no recanalization. Similarly, among patients with basilar artery occlusion, absence of atrial fibrillation was as an independent predictor of no recanalization (OR, 7.50; 95% CI, 1.40-40.35; P=0.02)., Conclusions: The use of relevant predictors of no recanalization and a rapid neurovascular evaluation may improve the selection of patients for more aggressive rescue strategies.

Background and Purpose: Poststroke hyperglycemia and diabetes mellitus are associated with lower thrombolytic efficacy and an increased risk of postischemic cerebral hemorrhage. We aimed to develop a rodent model of thrombolysis in diabetic stroke that mimics the clinical situation. Method- Male 6-week Type I diabetic rats (14 weeks old) were subjected to embolic focal stroke and treated with tissue-type plasminogen activator at 1.5 hours. Reperfusion and 24-hour neurological outcomes were measured and compared with nondiabetic control rats., Results: Diabetic rats exhibited resistance to thrombolytic reperfusion, larger infarction volumes, and increased intracerebral hemorrhage., Conclusions: This animal model would be relevant to future studies investigating pathophysiological mechanisms and in developing new therapeutic approaches to enhance the efficacy of tissue-type plasminogen activator thrombolysis in stroke patients with diabetes or poststroke hyperglycemia.

Stroke is one of the most debilitating diseases worldwide, with its occurrence increasing in Western societies. Central to the pathogenesis of thromboembolic stroke is the involvement of platelets. During thromboembolic events, nucleated cells undergo cell death, and platelets are also affected by parameters causing these incidents. Particularly, initiation of necrotic cell death at sites of vascular injury may play an important role in inducing inflammatory and repair processes. In the current research, the authors investigate whether a changed platelet ultrastructure is visible in thromboembolic stroke and whether it might be visible in platelets as apoptosis or necrosis. Therefore, in the current investigation, the authors study smears of platelet-rich plasma (PRP) from thromboembolic ischemic stroke patients to investigate whether a changed morphology is visible in distressed platelets. Scanning electron microscopy is used and platelets are viewed at up to 200,000× machine magnification. Results indicate that thromboembolic ischemic stroke causes membrane tears and swollen platelets, and this is indicative of necrosis. It is therefore concluded that this morphology might be due to the pro-coagulant activity characteristic of the disease.

We report a 33-year-old man with a history of chronic cannabis use who sustained myocardial infarction followed by cerebral infarction after a recent significant increase in cannabis use. This is the first case of cannabis-associated stroke of probable cardioembolic origin., (© 2012 National Stroke Association.)

Background and Purpose: Sildenafil provides restorative therapeutic benefits in the treatment of experimental stroke. The majority of experimental studies on treatment of stroke have been performed in young animals; however, stroke is primarily a disease of the aged. Thus, using MRI, we evaluated the effects of sildenafil treatment of embolic stroke in aged animals., Methods: Aged male Wistar rats (18 months) were subjected to embolic stroke and treated daily with saline (n=10) or with sildenafil (n=10) initiated at 24 hours and subsequently for 7 days after onset of ischemia. MRI measurements were performed at 24 hours and weekly to 6 weeks after embolization., Results: MRI and histological measurements demonstrated that sildenafil treatment of aged rats significantly enhanced angiogenesis and axonal remodeling after stroke compared to saline-treated aged rats. Local cerebral blood flow in the angiogenic area was elevated and expansion of the ipsilateral ventricle and, consequently, brain atrophy was significantly reduced in the sildenafil-treated rats., Conclusions: Treatment of embolic stroke in aged rats with sildenafil significantly augments angiogenesis and axonal remodeling, which increased local blood flow and reduced expansion of the ipsilateral ventricle 6 weeks after stroke compared to control aged rats. MRI can be used to investigate brain repair after stroke in aged rats.

Bicuspid aortic valve (BAV) is a common condition but is only rarely associated with embolic complications. We describe a 42-year-old man with recurrent posterior circulatory ischemic strokes that resulted in ataxia and cognitive impairment. Transesophageal echocardiography demonstrated a BAV with mild stenosis, moderate calcification, and a dilated ascending aorta. The degree of calcification and the valve phenotype might be important factors implicating the BAV as a rare cause of ischemic stroke., (Copyright © 2011 National Stroke Association. Published by Elsevier Inc. All rights reserved.)