Introducing the Concept of Sanctuary Sites in Ischemic Stroke.

BACKGROUND: The topography of arterial territories has been defined using digital maps of supratentorial infarcts. Regions with a high probability of infarction (Pi) exist in the deep compartment due to a paucity of collaterals. However, less attention has been given to regions with a low Pi. METHODS: Using published digital maps, patients with cortical stroke and documented vessel occlusion were included. Infarcts from T2-weighted magnetic resonance images were segmented and registered onto a standard brain template (Montreal Neurological Institute 152). Segmented magnetic resonance images were averaged to yield the Pi at a voxel level. The overall Pi for the combined arterial territories was calculated to ensure that Pi was in the range of 0 to 1. Sanctuary sites were identified as regions with Pi <0.1. RESULTS: There were 154 patients (63% men; median age, 69 years; and interquartile range, 57-78 years). The magnetic resonance imaging scan used for segmentation was performed at a median interval of 35 (interquartile range, 3-66) days after stroke onset. Sanctuary sites were present in the frontal (gyrus rectus, the paracentral lobule, and orbitofrontal and precentral gyrus), parietal (postcentral, supramarginal, and angular gyrus, superior and inferior parietal lobule, and precuneus and posterior cingulate), and occipital cortex (cuneus, middle, and superior occipital gyrus). CONCLUSIONS: We propose that following vessel occlusion, there are cortical regions with a low Pi, which we termed sanctuary sites. The anatomic basis for this observation is the compensatory capacity of leptomeningeal collaterals.

Thrombolysis for Wake-Up Stroke Versus Non-Wake-Up Unwitnessed Stroke: EOS Individual Patient Data Meta-Analysis.

BACKGROUND: Stroke with unknown time of onset can be categorized into 2 groups; wake-up stroke (WUS) and unwitnessed stroke with an onset time unavailable for reasons other than wake-up (non-wake-up unwitnessed stroke, non-WUS). We aimed to assess potential differences in the efficacy and safety of intravenous thrombolysis (IVT) between these subgroups. METHODS: Patients with an unknown-onset stroke were evaluated using individual patient-level data of 2 randomized controlled trials (WAKE-UP [Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke], THAWS [Thrombolysis for Acute Wake-Up and Unclear-Onset Strokes With Alteplase at 0.6 mg/kg]) comparing IVT with placebo or standard treatment from the EOS (Evaluation of Unknown-Onset Stroke Thrombolysis trial) data set. A favorable outcome was prespecified as a modified Rankin Scale score of 0 to 1 at 90 days. Safety outcomes included symptomatic intracranial hemorrhage at 22 to 36 hours and 90-day mortality. The IVT effect was compared between the treatment groups in the WUS and non-WUS with multivariable logistic regression analysis. RESULTS: Six hundred thirty-four patients from 2 trials were analyzed; 542 had WUS (191 women, 272 receiving alteplase), and 92 had non-WUS (42 women, 43 receiving alteplase). Overall, no significant interaction was noted between the mode of onset and treatment effect (P value for interaction=0.796). In patients with WUS, the frequencies of favorable outcomes were 54.8% and 45.5% in the IVT and control groups, respectively (adjusted odds ratio, 1.47 [95% CI, 1.01-2.16]). Death occurred in 4.0% and 1.9%, respectively (P=0.162), and symptomatic intracranial hemorrhage in 1.8% and 0.3%, respectively (P=0.194). In patients with non-WUS, no significant difference was observed in favorable outcomes relative to the control (37.2% versus 29.2%; adjusted odds ratio, 1.76 [0.58-5.37]). One death and one symptomatic intracranial hemorrhage were reported in the IVT group, but none in the control. CONCLUSIONS: There was no difference in the effect of IVT between patients with WUS and non-WUS. IVT showed a significant benefit in patients with WUS, while there was insufficient statistical power to detect a substantial benefit in the non-WUS subgroup. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: CRD42020166903.

Long-term persistence of viral RNA and inflammation in the CNS of macaques exposed to aerosolized Venezuelan equine encephalitis virus.

Venezuelan equine encephalitis virus (VEEV) is a positively-stranded RNA arbovirus of the genus Alphavirus that causes encephalitis in humans. Cynomolgus macaques are a relevant model of the human disease caused by VEEV and are useful in exploring pathogenic mechanisms and the host response to VEEV infection. Macaques were exposed to small-particle aerosols containing virus derived from an infectious clone of VEEV strain INH-9813, a subtype IC strain isolated from a human infection. VEEV-exposed macaques developed a biphasic fever after infection similar to that seen in humans. Maximum temperature deviation correlated with the inhaled dose, but fever duration did not. Neurological signs, suggestive of virus penetration into the central nervous system (CNS), were predominantly seen in the second febrile period. Electroencephalography data indicated a statistically significant decrease in all power bands and circadian index during the second febrile period that returned to normal after fever resolved. Intracranial pressure increased late in the second febrile period. On day 6 post-infection macaques had high levels of MCP-1 and IP-10 chemokines in the CNS, as well as a marked increase of T lymphocytes and activated microglia. More than four weeks after infection, VEEV genomic RNA was found in the brain, cerebrospinal fluid and cervical lymph nodes. Pro-inflammatory cytokines & chemokines, infiltrating leukocytes and pathological changes were seen in the CNS tissues of macaques euthanized at these times. These data are consistent with persistence of virus replication and/or genomic RNA and potentially, inflammatory sequelae in the central nervous system after resolution of acute VEEV disease.

Neuropsychological outcomes following endovascular clot retrieval and intravenous thrombolysis in ischemic stroke.

OBJECTIVES: Cognitive impairment, anxiety, depression, fatigue, and dependence in instrumental activities of daily living (ADL) are common after stroke; however, little is known about how these outcomes may differ following treatment with endovascular clot retrieval (ECR), intravenous tissue plasminogen activator (t-PA), or conservative management. METHODS: Patients were recruited after acute treatment and invited to participate in an outcome assessment 90-120 days post-stroke. The assessment included a cognitive test battery and several questionnaires. The COVID-19 pandemic led to significant disruptions in recruitment and data collection, and the t-PA and conservative management groups were combined into a standard medical care (SMC) group. RESULTS: Sixty-two participants were included in the study (ECR = 31, SMC = 31). Mean age was 66.5 (20-86) years, and 35 (56.5%) participants were male. Participants treated with ECR had significantly higher National Institutes of Health Stroke Scale scores at presentation and significantly lower education. After adjusting for stroke severity, premorbid intellectual ability, and age, treatment with ECR was associated with significantly better performances on measures of cognitive screening, visual working memory, and verbal learning and memory. Participants treated with ECR also experienced less fatigue and were more likely to achieve independence in basic and instrumental ADLs. Despite this, cognitive impairment and fatigue were still common among participants treated with ECR and anxiety and depression symptoms were experienced similarly by both groups. CONCLUSIONS: Cognitive impairment and fatigue were less common but still prevalent following treatment with ECR. This has important practical implications for stroke rehabilitation, and routine assessment of cognition, emotion, and fatigue is recommended for all stroke survivors regardless of stroke treatment and functional outcome.

Four intestinal ultrasound scores and bowel wall thickness alone correlated well with pediatric ulcerative colitis disease activity.

OBJECTIVES: Intestinal ultrasound (IUS) is a noninvasive tool in ulcerative colitis (UC), but scoring systems have mostly been developed for adults, Crohn's disease, and flaring UC. Our aim was to evaluate the performance of bowel wall thickness (BWT) and four IUS scores in pediatric patients with newly diagnosed UC. METHODS: Patients <18 years old with suspected UC were prospectively enrolled. Baseline IUS was done, and ulcerative colitis intestinal ultrasound score (UC-IUS), Milan criteria, simple pediatric activity ultrasound score (SPAUSS), and Civatelli Index were calculated. Mayo endoscopic segment subscore, pediatric ulcerative colitis activity index (PUCAI), and biomarkers were correlated with IUS using nonparametric and receiver operating characteristic analyses. RESULTS: Fifty-two patients (56% male, median age 13.9 years, interquartile range [IQR] 11.2-16.3) with 206 colon segments were included. Patients who needed hospitalization (n = 27/52) had significantly worse IUS (BWT and all scores) compared to those not hospitalized. For all patients, IUS scores and BWT significantly correlated with baseline endoscopic, clinical, and biochemical disease activity (p = 0.32-0.67, p < 0.05). BWT (τb = 0.53), UC-IUS (τb = 0.55), and Milan (τb = 0.52) had the strongest endoscopic correlations. For differentiating between endoscopic disease severity, BWT, UC-IUS, and Milan, had the highest areas under the curve (0.89-0.93). Using BWT alone, a thinner cut-off had improved sensitivity while maintaining high specificity: ≥2.5 mm for moderate/severe endoscopic inflammation (sensitivity 66%; specificity 94%) and ≥3.5 mm for severe endoscopic inflammation (sensitivity 92%; specificity 86%). CONCLUSIONS: BWT and all four IUS scores correlated well with endoscopic, clinical, and biochemical disease activity, and was another useful marker of severity in identifying patients needing hospitalization. Pediatric patients needed a thinner BWT cut-off, which should be accounted for when developing pediatric-specific scores. BWT alone may be just as clinically useful as composite US scores.

Adjunctive rescue therapy in acute large vessel occlusion secondary to underlying intracranial atherosclerotic disease.

BACKGROUND: The optimal treatment for patients with acute large vessel occlusion (LVO) secondary to intracranial atherosclerotic disease (ICAD) is unclear. Adjunctive rescue therapy with balloon angioplasty or stenting may be necessary to ensure vessel patency. We aimed to compare the safety and clinical outcomes of adjunctive rescue therapy vs lone thrombectomy for ICAD-related-LVO. METHODS: A retrospective propensity score matching analysis was performed in acute stroke patients who had endovascular thrombectomy between 2008 and 2021. We included patients with acute ICAD-related-LVO. The location of ICAD and exposure to thrombolysis were used to generate propensity score matching to estimate the likelihood of treatment by adjunctive rescue therapy. The primary clinical outcome (90-day modified rankin scale 0-2) and safety outcomes (symptomatic intracerebral hemorrhage) were assessed between the two groups. RESULTS: One-hundred and forty-four patients were included. The median (IQR) age was 68(59-76) and 52(36 %) were females. The baseline NIHSS was 12.5(8-19). Sixty-seven (47 %) patients had ICAD in M1 or M2 segments. Forty-six patients (67 %) had lone thrombectomy and twenty-one (28 %) had adjunctive rescue therapy. Propensity score matching did not demonstrate significant differences in 90-day modified Rankin Score 0-2 between lone thrombectomy (38.8 %) and adjunctive rescue therapy (39.3 %) (p = 0.3). Lone thrombectomy, compared to adjunctive rescue therapy, did not result in significantly more symptomatic intracerebral hemorrhages (2.8 % vs 8.3 %, p = 0.6), nor progressive occlusion (17 % vs 19 %, p = 0.8). CONCLUSION: We did not find significant differences in clinical outcomes and safety between lone thrombectomy and adjunctive rescue therapy. Randomized controlled studies are required to resolve the equipoise in treatment of ICAD-related-LVO.

Application of Perfusion Imaging in the Telehealth Setting for Acute Ischemic Stroke.

In the remote telehealth setting, computed tomography perfusion (CTP) provides important information in assessing the suitability of reperfusion therapy for patients with stroke syndromes. This review will discuss key concepts surrounding the use of CTP, including basic science, clinical applications, pitfalls, recent trials, and technical considerations. CTP can enhance decision­making for patients who are in the extended window from stroke onset, and this review will address key concepts relevant to its use.

Endovascular thrombectomy versus standard bridging thrombolytic with endovascular thrombectomy within 4·5 h of stroke onset: an open-label, blinded-endpoint, randomised non-inferiority trial.

BACKGROUND: The benefit of combined treatment with intravenous thrombolysis before endovascular thrombectomy in patients with acute ischaemic stroke caused by large vessel occlusion remains unclear. We hypothesised that the clinical outcomes of patients with stroke with large vessel occlusion treated with direct endovascular thrombectomy within 4·5 h would be non-inferior compared with the outcomes of those treated with standard bridging therapy (intravenous thrombolysis before endovascular thrombectomy). METHODS: DIRECT-SAFE was an international, multicentre, prospective, randomised, open-label, blinded-endpoint trial. Adult patients with stroke and large vessel occlusion in the intracranial internal carotid artery, middle cerebral artery (M1 or M2), or basilar artery, confirmed by non-contrast CT and vascular imaging, and who presented within 4·5 h of stroke onset were recruited from 25 acute-care hospitals in Australia, New Zealand, China, and Vietnam. Eligible patients were randomly assigned (1:1) via a web-based, computer-generated randomisation procedure stratified by site of baseline arterial occlusion and by geographic region to direct endovascular thrombectomy or bridging therapy. Patients assigned to bridging therapy received intravenous thrombolytic (alteplase or tenecteplase) as per standard care at each site; endovascular thrombectomy was also per standard of care, using the Trevo device (Stryker Neurovascular, Fremont, CA, USA) as first-line intervention. Personnel assessing outcomes were masked to group allocation; patients and treating physicians were not. The primary efficacy endpoint was functional independence defined as modified Rankin Scale score 0-2 or return to baseline at 90 days, with a non-inferiority margin of -0·1, analysed by intention to treat (including all randomly assigned and consenting patients) and per protocol. The intention-to-treat population was included in the safety analyses. The trial is registered with ClinicalTrials.gov, NCT03494920, and is closed to new participants. FINDINGS: Between June 2, 2018, and July 8, 2021, 295 patients were randomly assigned to direct endovascular thrombectomy (n=148) or bridging therapy (n=147). Functional independence occurred in 80 (55%) of 146 patients in the direct thrombectomy group and 89 (61%) of 147 patients in the bridging therapy group (intention-to-treat risk difference -0·051, two-sided 95% CI -0·160 to 0·059; per-protocol risk difference -0·062, two-sided 95% CI -0·173 to 0·049). Safety outcomes were similar between groups, with symptomatic intracerebral haemorrhage occurring in two (1%) of 146 patients in the direct group and one (1%) of 147 patients in the bridging group (adjusted odds ratio 1·70, 95% CI 0·22-13·04) and death in 22 (15%) of 146 patients in the direct group and 24 (16%) of 147 patients in the bridging group (adjusted odds ratio 0·92, 95% CI 0·46-1·84). INTERPRETATION: We did not show non-inferiority of direct endovascular thrombectomy compared with bridging therapy. The additional information from our study should inform guidelines to recommend bridging therapy as standard treatment. FUNDING: Australian National Health and Medical Research Council and Stryker USA.

Physiological and immunological changes in the brain associated with lethal eastern equine encephalitis virus in macaques.

Aerosol exposure to eastern equine encephalitis virus (EEEV) can trigger a lethal viral encephalitis in cynomolgus macaques which resembles severe human disease. Biomarkers indicative of central nervous system (CNS) infection by the virus and lethal outcome of disease would be useful in evaluating potential medical countermeasures, especially for therapeutic compounds. To meet requirements of the Animal Rule, a better understanding of the pathophysiology of EEEV-mediated disease in cynomolgus macaques is needed. In this study, macaques given a lethal dose of clone-derived EEEV strain V105 developed a fever between 2-3 days post infection (dpi) and succumbed to the disease by 6 dpi. At the peak of the febrile phase, there was a significant increase in the delta electroencephalography (EEG) power band associated with deep sleep as well as a sharp rise in intracranial pressure (ICP). Viremia peaked early after infection and was largely absent by the onset of fever. Granulocytosis and elevated plasma levels of IP-10 were found early after infection. At necropsy, there was a one hundred- to one thousand-fold increase in expression of traumatic brain injury genes (LIF, MMP-9) as well as inflammatory cytokines and chemokines (IFN-γ, IP-10, MCP-1, IL-8, IL-6) in the brain tissues. Phenotypic analysis of leukocytes entering the brain identified cells as primarily lymphoid (T, B, NK cells) with lower levels of infiltrating macrophages and activated microglia. Massive amounts of infectious virus were found in the brains of lethally-infected macaques. While no infectious virus was found in surviving macaques, quantitative PCR did find evidence of viral genomes in the brains of several survivors. These data are consistent with an overwhelming viral infection in the CNS coupled with a tremendous inflammatory response to the infection that may contribute to the disease outcome. Physiological monitoring of EEG and ICP represent novel methods for assessing efficacy of vaccines or therapeutics in the cynomolgus macaque model of EEEV encephalitis.

Thrombectomy versus Medical Management in Mild Strokes due to Large Vessel Occlusion: Exploratory Analysis from the EXTEND-IA Trials and a Pooled International Cohort.

OBJECTIVE: This study was undertaken to evaluate functional and safety outcomes for endovascular thrombectomy (EVT) versus medical management (MM) in patients with large vessel occlusion (LVO) and mild neurological deficits, stratified by perfusion imaging mismatch. METHODS: The pooled cohort consisted of patients with National Institutes of Health Stroke Scale (NIHSS) < 6 and internal carotid artery (ICA), M1, or M2 occlusions from the Extending the Time for Thrombolysis in Emergecy Neurological Deficits - Intra-Arterial (EXTEND-IA) Trial,  Tenecteplase vs Alteplase before Endovascular Thrombectomy in Ischemic Stroke (EXTEND-IA TNK) trials Part I/II and prospective data from 15 EVT centers from October 2010 to April 2020. RAPID software estimated ischemic core and mismatch. Patients receiving primary EVT (EVTpri ) were compared to those who received primary MM (MMpri ), including those who deteriorated and received rescue EVT, in overall and propensity score (PS)-matched cohorts. Patients were stratified by target mismatch (mismatch ratio ≥ 1.8 and mismatch volume ≥ 15ml). Primary outcome was functional independence (90-day modified Rankin Scale = 0-2). Secondary outcomes included safety (symptomatic intracerebral hemorrhage [sICH], neurological worsening, and mortality). RESULTS: Of 540 patients, 286 (53%) received EVTpri and demonstrated larger critically hypoperfused tissue (Tmax > 6 seconds) volumes (median [IQR]: 64 [26-96] ml vs MMpri : 40 [14-76] ml, p < 0.001) and higher presentation NIHSS (median [IQR]: 4 [2-5] vs MMpri : 3 [2-4], p < 0.001). Functional independence was similar (EVTpri : 77.4% vs MMpri : 75.6%, adjusted odds ratio [aOR] = 1.29, 95% confidence interval [CI] = 0.82-2.03, p = 0.27). EVT had worse safety regarding sICH (EVTpri : 16.3% vs MMpri : 1.3%, p < 0.001) and neurological worsening (EVTpri : 19.6% vs MMpri : 6.7%, p < 0.001). In 414 subjects (76.7%) with target mismatch, EVT was associated with improved functional independence (EVTpri : 77.4% vs MMpri : 72.7%, aOR = 1.68, 95% CI = 1.01-2.81, p = 0.048), whereas there was a trend toward less favorable outcomes with primary EVT (EVTpri : 77.4% vs MMpri : 83.3%, aOR = 0.39, 95% CI = 0.12-1.34, p = 0.13) without target mismatch (pinteraction  = 0.06). Similar findings were observed in a propensity score-matched subpopulation. INTERPRETATION: Overall, EVT was not associated with improved clinical outcomes in mild strokes due to LVO, and sICH was increased. However, in patients with target mismatch profile, EVT was associated with increased functional independence. Perfusion imaging may be helpful to select mild stroke patients for EVT. ANN NEUROL 2022;92:364-378.

Angiographic Systems for Classifying Distal Arterial Occlusions.

BACKGROUND: Extensive randomized controlled clinical trials for endovascular thrombectomy in anterior circulation large vessel occlusions (internal carotid arteries and M1 segment of middle cerebral arteries) have been published over the past decade, but there have not been randomized controlled trials for distal arterial occlusions to date. Distal arterial occlusion randomized controlled trials are essential to decide on patient selection, imaging criteria, and endovascular approach to improve the outcome and reduce complications. SUMMARY: The definition of distal arterial occlusion is however unclear, and we believe that a uniform nomenclature of distal arterial occlusions is essential for the design of robust randomized controlled studies. We undertook a systematic literature review and comprehensive analysis of 70 articles looking at distal arterial occlusions and previous attempts at classifying them as well as comparing their similarities and differences with a more selective look at the middle cerebral artery. Thirty-two articles were finally deemed suitable and included for this review. In this review article, we present 3 disparate classifications of distal arterial occlusions, namely, classical/anatomical, functional/imaging, and structural/calibre, and compare the similarities and differences between them. KEY MESSAGES: We propose the adoption of functional/imaging classification to guide the identification of distal arterial occlusions with the M2 segment starting at the point of bifurcation of the middle cerebral artery trunk/M1 segment. With regards to the anterior temporal artery, we propose that it will be considered a branch of the M1 and only be considered as the M2 segment if it is a holo-temporal artery. We believe that this is a practical method of classification in the time-critical decision-making period.

Meta-Analysis of the Use of Head Impulse Test and Head Impulse Test with Direction Changing Nystagmus and Test of Skew Deviation in the Diagnosis of Peripheral Vertigo and Stroke.

INTRODUCTION: The head impulse test (HIT) and HIT combined with direction-changing Nystagmus-Test of Skew deviation (HINTS) have been proposed as bedside tests to differentiate between peripheral and central causes of vertigo in the emergency department (ED). We conducted a meta-analysis of the HIT and HINTS tests to diagnose peripheral vertigo (PV) and central vertigo. METHODS: Pubmed, Google Scholar, EmBase, and articles references published in English up to July 2021 were searched for keywords "vertigo" or "acute vestibular syndrome" or "dizziness" and "head impulse" and "stroke." The bivariate method for meta-analysis was used to calculate positive (PLR) and negative likelihood ratios (NLR) and summary receiver operating characteristics area under the curve (AUC). RESULTS: A total of 11 studies were included analysing both HIT (8 studies, N = 417) and HINTS (6 studies, N = 405). HIT and HINTS were performed within 24 h in 4 of 11 studies. PLR and NLR for HIT in PV was 4.85 (95% CI: 2.83-8.08) and 0.19 (95% CI: 0.12-0.29, I2 63.25%), respectively. The AUC for HIT the diagnosis of PV and stroke was 0.90 and 0.92, respectively. PLR and NLR for a negative HIT in stroke was 5.85 (95% CI: 3.07-10.6) and 0.17 (95% CI: 0.08-0.30), respectively. PLR and NLR for peripheral HINTS pattern for PV was 17.3 (95% CI: 8.38-32.1) and 0.15 (95% CI: 0.07-0.26), respectively. PLR and NLR for central HINTS pattern for stroke: 5.61 (95% CI: 4.19-7.7) and 0.06 (95% CI: 0.03-0.12). In all included studies, HIT and HINTS exams were administered by neurology residents or neurology specialists with additional neuro-otology or neuro-ophthalmology subspeciality experience, and two studies included ED physicians. Raters reported high degree of bias and high concern regarding applicability in most domains of the quality assessment of diagnostic accuracy studies (QUADAS-2) tool. Meta-regression did not demonstrate a statistically significant effect of publication year, time to test, and type of assessor on sensitivity or false positive rate. CONCLUSION: The HIT and HINTS exams appear to be moderately good discriminators of central and PV. However, in most papers, the tests were administered by neurologists and were evaluated beyond 24 h, which may limit utility in the ED setting.

Pediatric Patient and Caregiver Satisfaction With the Use of Transabdominal Bowel Ultrasound in the Assessment of Inflammatory Bowel Diseases.

OBJECTIVES: Transabdominal bowel ultrasound (TABUS) is emerging as an attractive, noninvasive tool in inflammatory bowel disease (IBD). Patient and caregiver experience with TABUS is not well described. We aimed to determine pediatric patient and caregiver satisfaction with TABUS and the impact of IBD severity, gender, age, and a history of anxiety on satisfaction. METHODS: Pediatric patients (0-18 years old) with suspected IBD prospectively underwent baseline TABUS, magnetic resonance enterography (MRE), blood work, stool studies, and endoscopy. Patients and their caregiver each completed a cross-sectional satisfaction questionnaire (5-point Likert scale) after the baseline investigations. RESULTS: There were 54 patients included (67% male). The majority were completely satisfied and strongly agree TABUS was better tolerated than other investigations, regardless of disease severity ( P > 0.05). Patients with higher Simple Endoscopic Score for Crohn Disease (SES-CD) scores felt that TABUS increased their understanding of their IBD ( P < 0.05) and disease location ( P < 0.05). Patients with Crohn disease had similar responses to those with ulcerative colitis, but more strongly agreed that TABUS was better than MRE and endoscopy ( P < 0.05). Those with anxiety did not have an increased level of worry about potential ultrasound findings ( P > 0.05). CONCLUSIONS: Pediatric patients and their caregivers were highly satisfied with TABUS, preferring it to other modalities. It did not lead to increased worry, and was particularly important in those with severe IBD. These findings support wider implementation of this well tolerated and preferred monitoring tool in pediatrics.

Professional knowledge acquisition of dental students employed part-time as dental assistants.

INTRODUCTION: Whilst admission to dental school in many jurisdictions requires applicants to shadow dentists or undertake work experience at a dental practice, little is known about the impacts on professional learning when dental students work part-time as dental assistants whilst concurrently studying dentistry. This paper explores what, how and from whom dental students who work as dental assistants acquire professional knowledges during employment. METHODS: This study draws on a qualitative analysis of interviews with sixteen senior dental students who have extra-curricular part-time employment as dental assistants in private dental practices. RESULTS: Analysis produced four themes that relate to students learning in the professional environment: students learn about the responsibilities, rhythms and routines of practice, as well as patient communication and interactions. Students embedded in the dental team noticed and related to the dispositions and the work of dentistry. Students learned from all members of the dental team including clinical and non-clinical staff (reception, administration, laboratory and sterilisation). DISCUSSION: Students used their experiences in a practice setting to further their professional education. The ability to "read" a situation and formulate an appropriate response requires the integration of complex and actionable professional knowledges. CONCLUSION: This research study presents insight into the ways dental students employed as dental assistants are embedded in and learn from the dental team in a critically evaluative manner. Students professionally notice and make sense of complex practice environments whilst undertaking university studies to learn about practice routines, rhythms and responsibilities as well as advancing confidence in relating with patients. This study provides a stimulus for further research about the contribution of workplace experiences to dental education.

Convexity subarachnoid haemorrhage: a practical guide.

Atraumatic convexity subarachnoid haemorrhage describes spontaneous bleeding into the convexities of the brain sulci without parenchymal involvement. Its many causes include reversible cerebral vasoconstriction syndrome, cerebral sinus venous thrombosis, posterior reversible encephalopathy syndrome and (in older people) cerebral amyloid angiopathy. We describe the clinical and radiological features of non-traumatic convexity subarachnoid haemorrhage with its various presentations, causes, treatments and prognoses, and use clinical vignettes to highlight important clinical points and pitfalls.

Alteplase for Stroke With Unknown Onset Time in Chronic Kidney Disease: A Pooled Analysis of Individual Participant Data.

BACKGROUND: Although chronic kidney disease (CKD) is associated with worse stroke outcomes, data regarding the influence of CKD on intravenous thrombolysis outcomes are scarce. We sought to assess the efficacy and safety of intravenous thrombolysis for acute ischemic stroke with unknown onset time in patients with CKD. METHODS: Patients with an acute stroke of unknown onset time from the EOS trials (Evaluation of Unknown Onset Stroke Thrombolysis) collaboration were evaluated using an individual patient-level database of randomized controlled trials comparing intravenous thrombolysis with placebo/standard treatment. CKD was defined as baseline estimated glomerular filtration rate of <60 ml/min/1.73m2 Mixed-effect logistic-regression analysis was performed to evaluate treatment effects. A favorable outcome was defined as a modified Rankin Scale score of 0 to 1 at 90 days. Safety outcomes were symptomatic intracranial hemorrhage at 22 to 36 hours and 90-day mortality. RESULTS: Baseline data on renal function were available for 688 of 843 patients. Of these, CKD was present in 146 (21%), including 69 of 351 patients receiving alteplase and 77 of 337 patients receiving placebo/standard treatment. Overall, treatment with alteplase was associated with higher odds of favorable outcome, and CKD did not modify the treatment effect (Pinteraction=0.834). A favorable outcome was observed in 31 of 69 (46%) patients with CKD in the alteplase group and in 28 of 77 (36%) patients with CKD in the control group (adjusted odds ratio, 1.19 [95% CI, 0.55-2.58]). Among patients with CKD, symptomatic intracranial hemorrhage occurred in 2 patients (3%) in the alteplase group but in none of the controls (P=0.133). At 90 days, death was reported in 3 patients (4%) in the alteplase group compared with 2 patients (3%) in the controls (P=0.539). CONCLUSIONS: The present analysis indicates that the benefit of alteplase does not differ between stroke patients with unknown onset time with and without CKD, although the statistical power was lacking to confirm the efficacy in subgroups. This study only applies to mild-to-moderate or predialysis CKD.

Thrombolysis Guided by Perfusion Imaging up to 9 Hours after Onset of Stroke.

BACKGROUND: The time to initiate intravenous thrombolysis for acute ischemic stroke is generally limited to within 4.5 hours after the onset of symptoms. Some trials have suggested that the treatment window may be extended in patients who are shown to have ischemic but not yet infarcted brain tissue on imaging. METHODS: We conducted a multicenter, randomized, placebo-controlled trial involving patients with ischemic stroke who had hypoperfused but salvageable regions of brain detected on automated perfusion imaging. The patients were randomly assigned to receive intravenous alteplase or placebo between 4.5 and 9.0 hours after the onset of stroke or on awakening with stroke (if within 9 hours from the midpoint of sleep). The primary outcome was a score of 0 or 1 on the modified Rankin scale, on which scores range from 0 (no symptoms) to 6 (death), at 90 days. The risk ratio for the primary outcome was adjusted for age and clinical severity at baseline. RESULTS: After 225 of the planned 310 patients had been enrolled, the trial was terminated because of a loss of equipoise after the publication of positive results from a previous trial. A total of 113 patients were randomly assigned to the alteplase group and 112 to the placebo group. The primary outcome occurred in 40 patients (35.4%) in the alteplase group and in 33 patients (29.5%) in the placebo group (adjusted risk ratio, 1.44; 95% confidence interval [CI], 1.01 to 2.06; P = 0.04). Symptomatic intracerebral hemorrhage occurred in 7 patients (6.2%) in the alteplase group and in 1 patient (0.9%) in the placebo group (adjusted risk ratio, 7.22; 95% CI, 0.97 to 53.5; P = 0.05). A secondary ordinal analysis of the distribution of scores on the modified Rankin scale did not show a significant between-group difference in functional improvement at 90 days. CONCLUSIONS: Among the patients in this trial who had ischemic stroke and salvageable brain tissue, the use of alteplase between 4.5 and 9.0 hours after stroke onset or at the time the patient awoke with stroke symptoms resulted in a higher percentage of patients with no or minor neurologic deficits than the use of placebo. There were more cases of symptomatic cerebral hemorrhage in the alteplase group than in the placebo group. (Funded by the Australian National Health and Medical Research Council and others; EXTEND ClinicalTrials.gov numbers, NCT00887328 and NCT01580839.).

Topographic Evolution of Anterior Cerebral Artery Infarction and Its Impact on Motor Impairment.

INTRODUCTION: Motor deficit is common following anterior cerebral artery (ACA) stroke. This study aimed to determine the impact on the motor outcome, given the location of descending corticofugal fiber tracts (from the primary motor cortex [M1], dorsal and ventral premotor area [PMdv], and supplementary motor area [SMA]) and the regional variations in collateral support of the ACA territory. METHODS: Patients with ACA vessel occlusion were included. Disruption to corticofugal fibers was inferred by overlap of tracts with a lesion on computed tomography perfusion at the onset and on magnetic resonance imaging (MRI) poststroke. The motor outcome was defined by dichotomized and combined National Institute of Health Stroke Scale (NIHSS) sub-scores for the arm and leg. Multivariate hierarchical partitioning was used to analyze the proportional contribution of the corticofugal fibers to the motor outcome. RESULTS: Forty-seven patients with a median age of 77.5 (interquartile range 68.0-84.5) years were studied. At the stroke onset, 96% of patients showed evidence of motor deficit on the NIHSS, and the proportional contribution of the corticofugal fibers to motor deficit was M1-33%, SMA-33%, and PMdv-33%. By day 7, motor deficit was present in <50% of patients and contribution of M1 fiber tracts to the motor deficit was reduced (M1-10.2%, SMA-61.0%, PMdv-28.8%). We confirmed our findings using publicly available high-resolution templates created from Human Connectome Project data. This also showed a reduction in involvement of M1 fiber tracts on initial perfusion imaging (33%) compared to MRI at a median time of 7 days poststroke (11%). CONCLUSION: Improvements in the motor outcome seen in ACA stroke may be due to the relative sparing of M1 fiber tracts from infarction. This may occur as a consequence of the posterior location of M1 fiber tracts and the evolving topography of ACA stroke due to the compensatory capacity of leptomeningeal anastomoses.

Stroke in patients with cancer in the era of hyperacute stroke intervention.

BACKGROUND: The natural history of patients with stroke and cancer remains poorly understood in the modern era of hyperacute stroke therapies (recombinant tissue plasminogen activator and endovascular clot retrieval (ECR)). Prior to these advances in stroke treatment, a highly cited study reported median overall survival (mOS) 4.5 months after stroke in a cohort of patients with cancer (2004, n = 96). AIMS: Our hypothesis is that patients with stroke and cancer have better outcome than in earlier studies. METHODS: Retrospective analysis of admission to a tertiary Stroke Unit between January 2015 and September 2017 (n = 1910), evaluation of hospital records and cancer treatment records. Cancer was categorised as early stage (Stages I and II) and advanced stage (Stage III or IV) using the RD-Staging system. Survival analysis was performed in R. RESULTS: There were 143 stroke patients with cancer (62% male) with mean age 73.2 ± 12.5 years. Ischaemic stroke occurred in 74.1% and 45 of 106 (42.5%) patients received intravenous thrombolysis (34/45) and/or ECR (11/45). One patient who received ECR died within 30 days of stroke. Those with early stage disease had mOS of 19.6 months (interquartile range (IQR) 3.1-31.5 months) and in advanced stage cancer mOS was 2.5 months (IQR 0.4-6.3 months; P < 0.01). CONCLUSION: In the modern era of stroke therapy, our cohort of patients with advanced cancer has lower survival post-stroke compared to those with early stage cancer.

Determinants of the de-implementation of low-value care: a multi-method study.

BACKGROUND: There is an urgent need to understand the determinants (i.e., barriers and facilitators) of de-implementation. The purpose of this study was to develop a comprehensive list of determinants of the de-implementation of low-value care from the published literature and to compare this list to determinants identified by a group of stakeholders with lived experience with de-implementation. METHODS: This was a two-phase multi-method study. First, a systematic review examined published barriers and facilitators to de-implementation. Articles were identified through searches within electronic databases, reference lists and the grey literature. Citations were screened independently and in duplicate and included if they were: 1) written in English; and 2) described a barrier or facilitator to de-implementation of any clinical practice in adults (age ≥ 18 years). 'Raw text' determinants cited within included articles were extracted and synthesized into a list of representative determinants using conventional content analysis. Second, semi-structured interviews were conducted with decision-makers (unit managers and medical directors) and healthcare professionals working in adult critical care medicine to explore the overlap between the determinants found in the systematic review to those experienced in critical care medicine. Thematic content analysis was used to identify key themes emerging from the interviews. RESULTS: In the systematic review, reviewers included 172 articles from 35,368 unique citations. From 437 raw text barriers and 280 raw text facilitators, content analysis produced 29 distinct barriers and 24 distinct facilitators to de-implementation. Distinct barriers commonly cited within raw text included 'lack of credible evidence to support de-implementation' (n = 90, 21%), 'entrenched norms and clinicians' resistance to change (n = 43, 21%), and 'patient demands and preferences' (n = 28, 6%). Distinct facilitators commonly cited within raw text included 'stakeholder collaboration and communication' (n = 43, 15%), and 'availability of credible evidence' (n = 33, 12%). From stakeholder interviews, 23 of 29 distinct barriers and 20 of 24 distinct facilitators from the systematic review were cited as key themes relevant to de-implementation in critical care. CONCLUSIONS: The availability and quality of evidence that identifies a clinical practice as low-value, as well as healthcare professional willingness to change, and stakeholder collaboration are common and important determinants of de-implementation and may serve as targets for future de-implementation initiatives. TRIAL REGISTRATION: The systematic review was registered in PROSPERO CRD42016050234 .