12 research outputs found
Apprentissage de similarités pour l'aide à l'organisation de contenus audiovisuels
TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF
Chemical and structural stability of La0.6Sr0.4Co0.2Fe0.8O3−δ ceramic vs. medium/high water vapor pressure
During the last decades, perovskite-type oxides have received large attention as potential electrolytes and electrodes for Solid Oxide Fuel Cells (SOFC), including Proton Ceramic Fuel Cells (PCFC), gas separation membranes and High Temperature Steam Electrolysers (HTSE). A thermal treatment in an autoclave, at a temperature close to an operating temperature, was used to measure the chemical stability of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF6428) ceramic under medium and high water pressure (~20 and 40 bar). This mixed ionic−electronic conductor (MIEC) exhibits interesting properties as cathode of fuel cell materials. The reactivity rate of the investigated LSCF6428 sample under the protonation process conditions (several weeks at 550 °C using CO2-free and CO2-saturated water) was studied in order to evaluate a potential use of this compound. Bulk and surface structural/chemical changes were characterized by optical microscopy, TGA, dilatometry, Raman and ATR-FTIR spectroscopy. The results revealed only minor surface modifications in the case of ceramic treated under medium vapor pressure (20 bar) using CO2-free water. On the contrary, under higher pressure (40 bar) and CO2-saturated water several second phases were detected, namely strontianite, cobalt oxides and hematite. The chemical/structural stability of LSCF6428 is compared with previously investigated Rare-Earth nickelate ceramics: La2NiO4+δ / Pr2NiO4+δ / Nd2NiO4+δ
Prediction of Early Neurological Deterioration in Individuals With Minor Stroke and Large Vessel Occlusion Intended for Intravenous Thrombolysis Alone
International audienceImportance: The best reperfusion strategy in patients with acute minor stroke and large vessel occlusion (LVO) is unknown. Accurately predicting early neurological deterioration of presumed ischemic origin (ENDi) following intravenous thrombolysis (IVT) in this population may help to select candidates for immediate transfer for additional thrombectomy.Objective: To develop and validate an easily applicable predictive score of ENDi following IVT in patients with minor stroke and LVO.Design, setting, and participants: This multicentric retrospective cohort included 729 consecutive patients with minor stroke (National Institutes of Health Stroke Scale [NIHSS] score of 5 or less) and LVO (basilar artery, internal carotid artery, first [M1] or second [M2] segment of middle cerebral artery) intended for IVT alone in 45 French stroke centers, ie, including those who eventually received rescue thrombectomy because of ENDi. For external validation, another cohort of 347 patients with similar inclusion criteria was collected from 9 additional centers. Data were collected from January 2018 to September 2019.Main outcomes and measures: ENDi, defined as 4 or more points' deterioration on NIHSS score within the first 24 hours without parenchymal hemorrhage on follow-up imaging or another identified cause.Results: Of the 729 patients in the derivation cohort, 335 (46.0%) were male, and the mean (SD) age was 70 (15) years; of the 347 patients in the validation cohort, 190 (54.8%) were male, and the mean (SD) age was 69 (15) years. In the derivation cohort, the median (interquartile range) NIHSS score was 3 (1-4), and the occlusion site was the internal carotid artery in 97 patients (13.3%), M1 in 207 (28.4%), M2 in 395 (54.2%), and basilar artery in 30 (4.1%). ENDi occurred in 88 patients (12.1%; 95% CI, 9.7-14.4) and was strongly associated with poorer 3-month outcomes, even in patients who underwent rescue thrombectomy. In multivariable analysis, a more proximal occlusion site and a longer thrombus were independently associated with ENDi. A 4-point score derived from these variables-1 point for thrombus length and 3 points for occlusion site-showed good discriminative power for ENDi (C statistic = 0.76; 95% CI, 0.70-0.82) and was successfully validated in the validation cohort (ENDi rate, 11.0% [38 of 347]; C statistic = 0.78; 95% CI, 0.70-0.86). In both cohorts, ENDi probability was approximately 3%, 7%, 20%, and 35% for scores of 0, 1, 2 and 3 to 4, respectively.Conclusions and relevance: The substantial ENDi rates observed in these cohorts highlights the current debate regarding whether to directly transfer patients with IVT-treated minor stroke and LVO for additional thrombectomy. Based on the strong associations observed, an easily applicable score for ENDi risk prediction that may assist decision-making was derived and externally validated
Predictors of Parenchymal Hematoma After Mechanical Thrombectomy
International audienceBackground and Purpose— Parenchymal hematoma (PH) is a rare but dreadful complication of acute ischemic stroke with unclear underlying mechanisms. We aimed to study the incidence and predictors of PH after mechanical thrombectomy. Methods— Data from a prospective observational multicenter registry was screened to identify acute ischemic stroke patients with an anterior circulation large vessel occlusion who underwent mechanical thrombectomy. Clinical, imaging, and procedural characteristics were used for the analysis, including brain imaging systematically performed at 24 hours. PH occurrence was assessed according to ECASS (European Collaborative Acute Stroke Study) criteria. Univariate and multivariable analyses were performed to identify predictors of PH. Results— A total of 1316 patients were included in the study. PH occurred in 153 out of 1316 patients (11.6%) and was associated with a lower rate of favorable outcome and increased mortality. On multivariable analysis, age (per 1 year increase, odds ratio [OR], 1.01; 95% CI, 1.00–1.03; P =0.05), current smoking (OR, 2.02; 95% CI, 1.32–3.09; P <0.01), admission Alberta Stroke Program Early CT Score (per a decrease of 1 point, OR, 1.70; 95% CI, 1.18–2.44; P <0.01), general anesthesia (OR, 1.98; 95% CI, 1.36–2.90; P <0.001), angiographic poor collaterals (OR, 2.13; 95% CI, 1.36–3.33; P <0.001) and embolization in new territory (OR, 2.94; 95% CI, 1.70–5.10; P <0.001) were identified as independent predictors of PH. Conclusions— PH occurred at a rate of 11.6% after mechanical thrombectomy, with high morbidity and mortality. Our study identified clinical, radiological, and procedural predictors of PH occurrence that can serve as the focus of future periprocedural management studies with the aim of reducing its occurrence. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT03776877
Post-Thrombolysis Recanalization in Stroke Referrals for Thrombectomy
International audienceBackground and Purpose—Whether all acute stroke patients with large vessel occlusion need to undergo intravenous thrombolysis before mechanical thrombectomy (MT) is debated as (1) the incidence of post-thrombolysis early recanalization (ER) is still unclear; (2) thrombolysis may be harmful in patients unlikely to recanalize; and, conversely, (3) transfer for MT may be unnecessary in patients highly likely to recanalize. Here, we determined the incidence and predictors of post-thrombolysis ER in patients referred for MT and derive ER prediction scores for trial design. Methods—Registries from 4 MT-capable centers gathering patients referred for MT and thrombolyzed either on site (mothership) or in a non MT-capable center (drip-and-ship) after magnetic resonance– or computed tomography–based imaging between 2015 and 2017. ER was identified on either first angiographic run or noninvasive imaging. In the magnetic resonance imaging subsample, thrombus length was determined on T2*-based susceptibility vessel sign. Independent predictors of no- ER were identified using multivariable logistic regression models, and scores were developed according to the magnitude of regression coefficients. Similar registries from 4 additional MT-capable centers were used as validation cohort. Results—In the derivation cohort (N=633), ER incidence was ≈20%. In patients with susceptibility vessel sign (n=498), no-ER was independently predicted by long thrombus, proximal occlusion, and mothership paradigm. A 6-point score derived from these variables showed strong discriminative power for no-ER (C statistic, 0.854) and was replicated in the validation cohort (n=353; C statistic, 0.888). A second score derived from the whole sample (including negative T2* or computed tomography–based imaging) also showed good discriminative power and was similarly validated. Highest grades on both scores predicted no-ER with >90% specificity, whereas low grades did not reliably predict ER. Conclusions—The substantial ER rate underlines the benefits derived from thrombolysis in bridging populations. Both prediction scores afforded high specificity for no-ER, but not for ER, which has implications for trial design
Higher Annual Operator Volume Is Associated With Better Reperfusion Rates in Stroke Patients Treated by Mechanical Thrombectomy
Safety and Outcome of Carotid Dissection Stenting During the Treatment of Tandem Occlusions: A Pooled Analysis of TITAN and ETIS
International audienceBackground and Purpose: The efficacy of endovascular therapy in patients with acute ischemic stroke due to tandem occlusion is comparable to that for isolated intracranial occlusion in the anterior circulation. However, the optimal management of acute cervical internal carotid artery lesions is unknown, especially in the setting of carotid dissection, but emergency carotid artery stenting (CAS) is frequently considered. We investigated the safety and efficacy of emergency CAS for carotid dissection in patients with acute stroke with tandem occlusion in current clinical practice. Methods: We retrospectively analyzed a prospectively maintained database composed of 2 merged multicenter international observational real-world registries (Endovascular Treatment in Ischemic Stroke and Thrombectomy in Tandem Lesion). Data from endovascular therapy performed in the treatment of tandem occlusions related to acute cervical carotid dissection between January 2012 and January 2019 at 24 comprehensive stroke centers were analyzed. Results: The study assessed 136 patients with tandem occlusion due to dissection, including 65 (47.8%) treated with emergency CAS and 71 (52.2%) without. The overall rates of favorable outcome (90-day modified Rankin Scale score, 0–2) and successful reperfusion (modified Thrombolysis in Cerebral Infarction, 2b–3) were 58.0% (n=76 [95% CI, 49.6%–66.5%]) and 77.9% (n=106 [95% CI, 71.0%–85.0%]), respectively. In subgroup analyses, the rate of successful reperfusion (89.2% versus 67.6%; adjusted odds ratio, 2.24 [95% CI, 1.33–3.77]) was higher after CAS, whereas the 90-day favorable outcome (54.3% versus 61.4%; adjusted odds ratio, 0.84 [95% CI, 0.58–1.22]), symptomatic intracerebral hemorrhage (sICH; 10.8% versus 5.6%; adjusted odds ratio, 1.59 [95% CI, 0.79–3.17]), and 90-day mortality (8.0% versus 5.8%; adjusted odds ratio, 1.00 [95% CI, 0.48–2.09]) did not differ. In sensitivity analyses of patients with successful intracranial reperfusion, CAS was not associated with an improved clinical outcome. Conclusions: Emergency stenting of the dissected cervical carotid artery during endovascular therapy for tandem occlusions seems safe, whatever the quality of the intracranial reperfusion
Prognosis and risk factors associated with asymptomatic intracranial hemorrhage after endovascular treatment of large vessel occlusion stroke: a prospective multicenter cohort study
International audienceBackground and purpose: Asymptomatic intracranial hemorrhage (aICH) is a common occurrence after endovascular treatment (EVT) for acute ischemic stroke (AIS). The aims of this study were to address its impact on 3-month functional outcome and to identify risk factors for aICH after EVT. Methods: Patients with AIS attributable to anterior circulation large vessel occlusion who underwent EVT were enrolled in a multicenter prospective registry. Based on imaging performed 22–36 h post-EVT, we included patients with no intracranial hemorrhage (ICH) or aICH. Poor outcome defined as a 3-month modified Rankin Scale (mRS) score 4–6 and overall 3-month mRS score distribution were compared according to presence/absence of aICH, and aICH subtype using logistic regression. We assessed the risk factors of aICH using a multivariate logistic regression model. Results: Of the 1526 patients included in the study, 653 (42.7%) had aICH. Patients with aICH had a higher rate of poor outcome: odds ratio (OR) 1.88 (95% confidence interval [CI] 1.44–2.44). Shift analysis of mRS score found a fully adjusted OR of 1.79 (95% CI 1.47–2.18). Hemorrhagic infarction (OR 1.63 [95% CI 1.22–2.18]) and parenchymal hematoma (OR 2.99 [95% CI 1.77–5.02]) were associated with higher risk of poor outcome. Male sex, diabetes, coronary artery disease, baseline National Institutes of Health Stroke Scale score and Alberta Stroke Program Early Computed Tomography Score, number of passes and onset to groin puncture time were independently associated with aICH. Conclusions: Patients with aICH, irrespective of the radiological pattern, have a worse functional outcome at 3 months compared with those without ICH after EVT for AIS. The number of EVT passes and the time from onset to groin puncture are factors that could be modified to reduce deleterious ICH
Mechanical Thrombectomy for Acute Ischemic Stroke Amid the COVID-19 Outbreak
International audienceBackground and Purpose: The efficiency of prehospital care chain response and the adequacy of hospital resources are challenged amid the coronavirus disease 2019 (COVID-19) outbreak, with suspected consequences for patients with ischemic stroke eligible for mechanical thrombectomy (MT). Methods: We conducted a prospective national-level data collection of patients treated with MT, ranging 45 days across epidemic containment measures instatement, and of patients treated during the same calendar period in 2019. The primary end point was the variation of patients receiving MT during the epidemic period. Secondary end points included care delays between onset, imaging, and groin puncture. To analyze the primary end point, we used a Poisson regression model. We then analyzed the correlation between the number of MTs and the number of COVID-19 cases hospitalizations, using the Pearson correlation coefficient (compared with the null value). Results: A total of 1513 patients were included at 32 centers, in all French administrative regions. There was a 21% significant decrease (0.79; [95%CI, 0.76–0.82]; P <0.001) in MT case volumes during the epidemic period, and a significant increase in delays between imaging and groin puncture, overall (mean 144.9±SD 86.8 minutes versus 126.2±70.9; P <0.001 in 2019) and in transferred patients (mean 182.6±SD 82.0 minutes versus 153.25±67; P <0.001). After the instatement of strict epidemic mitigation measures, there was a significant negative correlation between the number of hospitalizations for COVID and the number of MT cases ( R 2 −0.51; P =0.04). Patients treated during the COVID outbreak were less likely to receive intravenous thrombolysis and to have unwitnessed strokes (both P <0.05). Conclusions: Our study showed a significant decrease in patients treated with MTs during the first stages of the COVID epidemic in France and alarming indicators of lengthened care delays. These findings prompt immediate consideration of local and regional stroke networks preparedness in the varying contexts of COVID-19 pandemic evolution
Risk for Major Bleeding in Patients Receiving Ticagrelor Compared With Aspirin After Transient Ischemic Attack or Acute Ischemic Stroke in the SOCRATES Study (Acute Stroke or Transient Ischemic Attack Treated With Aspirin or Ticagrelor and Patient Outcomes)
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