iSPAN: Explainable prediction of outcomes post thrombectomy with Machine Learning

PURPOSE

This study aimed to develop and evaluate a machine learning model and a novel clinical score for predicting outcomes in stroke patients undergoing endovascular thrombectomy.

MATERIALS AND METHODS

This retrospective study included all patients aged over 18 years with an anterior circulation stroke treated at a thrombectomy centre from 2010 to 2020 with external validation. The primary outcome was day 90 mRS ≥3. Existing clinical scores (SPAN and PRE) and Machine Learning (ML) models were compared. A novel clinical score (iSPAN) was derived by adding an optimised weighting of the most important ML features to the SPAN.

RESULTS

812 patients were initially included (397 female, average age 73), 63 for external validation. The best performing clinical score and ML model were SPAN and XGB (sensitivity, specificity and accuracy 0.290, 0.967, 0.628 and 0.693, 0.783, 0.738 respectively). A significant difference was found overall and our XGB model was more accurate than SPAN (p < 0.0018). The most important features were Age, mTICI and total number of passes. The addition of 11 points for mTICI of ≤2B and 3 points for ≥3 passes to the SPAN achieved the best accuracy and was used to create the iSPAN. iSPAN was not significantly less accurate than our XGB model (p > 0.5). In the external validation set, iSPAN and SPAN achieved sensitivity, specificity, and accuracy of (0.735, 0.862, 0.79) and (0.471, 0.897, 0.67) respectively.

CONCLUSION

iSPAN incorporates machine-derived features to achieve better predictions compared to existing clinical scores. It is not inferior to our XGB model and is externally generalisable.

White blood cell subtypes and neutrophil extracellular traps content as biomarkers for stroke etiology in acute ischemic stroke clots retrieved by mechanical thrombectomy

BACKGROUND

Lymphocytes, macrophages, neutrophils, and neutrophil extracellular traps (NETs) associate with stroke risk factors and form a thrombus through different mechanisms. We investigated the total WBCs, WBC subtypes and NETs composition in acute ischemic stroke (AIS) clots to identify possible etiological differences that could help us further understand the process of thrombosis that leads to AIS.

METHODS

AIS clots from 100 cases each of atherothrombotic (AT), cardioembolic (CE) and cryptogenic stroke etiology were collected per-pass as part of the CÚRAM RESTORE registry of AIS clots. Martius Scarlet Blue stain was used to identify the main histological components of the clots. Immunohistochemical staining was used to identify neutrophils, lymphocytes, macrophages, and NETs patterns. The cellular and histological components were quantified using Orbit Image Analysis software.

RESULTS

AT clots were larger, with more red blood cells and fewer WBCs than CE clots. AT clots had more lymphocytes and cryptogenic clots had fewer macrophages than other etiologies. Most significantly, CE clots showed higher expression of neutrophils and extracellular web-like NETs compared to AT and cryptogenic clots. There was also a significantly higher distribution of web-like NETs around the periphery of the CE clots while a mixed distribution was observed in AT clots.

CONCLUSION

The difference in neutrophil and NETs expression in clots from different etiologies may provide insight into the mechanism of clot formation.

Standardised aspiration first approach reduces materials used and cost of thrombectomy procedure in anterior circulation large vessel occlusion stoke

PURPOSE

The aim of this study is to compare the volume of equipment and equipment costs in a cohort of consecutive patients with anterior circulation large vessel occlusion treated with a standardised aspiration first approach to those treated with a stent retriever first approach.

METHODS

The equipment used in each case was recorded from a prospectively maintained equipment log. We then compared the volume of equipment used in each group. The cost of this equipment was calculated for each group based on local prices. Estimated equipment costs were then compared.

RESULTS

Our patient cohort consisted of 127 consecutive patients who were treated with a non-standardised stent retriever first technique (group A), 127 consecutive patients who underwent a new standardised aspiration first technique (group B), and 126 consecutive patients reflecting more recent practise where an aspiration first approach has been an established practise in our department (group C).Standardised aspiration first approach results in reduced equipment usage in thrombectomy procedures. The total equipment cost per case in the stent retriever first group (group A) was significantly higher at €4726.4 ($4818.3) versus €3093.1 ($3153.2) in the aspiration first group (group B), a reduction of 34.6% and €2798.5 ($2852.9) in the current practise group (group C), a reduction of 40.8%. There was no statistically significant difference in cost between groups B and C (p  =  0.57).

CONCLUSION

The standardised aspiration first technique utilised a reduced volume of equipment and confers a 40.8% reduced cost per procedure compared to a stent retriever first approach.

The impact of the COVID-19 pandemic on the provision of endovascular thrombectomy for stroke: an Irish perspective

BACKGROUND

The COVID-19 pandemic produced unprecedented challenges to healthcare systems. These challenges were amplified in the setting of endovascular thrombectomy (EVT) for large vessel occlusion strokes given the time-sensitive nature of the procedure.

AIMS

To assess the impact of the COVID-19 pandemic on service provision at the primary endovascular stroke centre in Ireland.

METHODS

A retrospective review of the National Thrombectomy Service database was performed. All patients undergoing EVT from 1 January to 31 December inclusive of 2019 to 2021 were included. Patient demographics, functional outcomes and endovascular treatment time metrics were recorded.

RESULTS

Data from 2019, 2020 and 2021 were extracted. Three hundred seven thrombectomies were performed in 2019 and 2020; this number increased to 327 in 2021. Median time from arrival to groin puncture for thrombectomy was 64 min in 2019, increasing to 65 min in 2020. In 2021, this decreased to 52 min. Median time taken from groin puncture to first perfusion remained stable from 2019 to 2021 years at 20 min. Total duration of emergency thrombectomies reduced from 32 min in 2019 to 27 min in 2020. This increased to 29 min in 2021.

CONCLUSIONS

Despite the myriad of challenges presented by the pandemic, service provision at the primary Irish ESC, and the referring hospitals, has proven to be robust. Procedural time metrics were maintained whilst the expected reduction in number of EVTs performed did not materialise, there actually being a significant increase in number of EVTs performed in the pandemic's second year.

Outcomes following poor-grade aneurysmal subarachnoid haemorrhage: a prospective observational study

BACKGROUND

Up to 35% of aneurysmal subarachnoid haemorrhage (aSAH) cases may present as poor grade, defined as World Federation of Neurosurgical Societies (WFNS) grades IV and V. In this study, we evaluate functional outcomes and prognostic factors.

METHODS

This prospective study included all patients referred to a national, centralized neurosurgical service with a diagnosis of poor-grade aSAH between 01/01/2016 and 31/12/2019. Multivariable logistic regression models were used to estimate probability of poor functional outcomes, defined as a Glasgow Outcome Scale (GOS) of 1-3 at 3 months.

RESULTS

Two hundred fifty-seven patients were referred, of whom 116/257 (45.1%) underwent treatment of an aneurysm, with 97/116 (84%) treated within 48 h of referral. Median age was 62 years (IQR 51-69) with a female predominance (167/257, 65%). Untreated patients tended to be older; 123/141 (87%) had WFNS V, 60/141 (45%) unreactive pupils and 21/141 (16%) circulatory arrest. Of all referred patients, poor outcome occurred in 169/230 (73.5%). Unreactive pupils or circulatory arrest conferred a universally poor prognosis, with mortality in 55/56 (98%) and 19/19 (100%), respectively. The risk of a poor outcome was 14.1% (95% CI 4.5-23.6) higher in WFNS V compared with WFNS IV. Age was important in patients without circulatory arrest or unreactive pupils, with risk of a poor outcome increasing by 1.8% per year (95% CI 1-2.7). In patients undergoing aneurysm securement, 48/101 (47.5%) had a poor outcome, with age, rebleeding, vasospasm and cerebrospinal fluid (CSF) diversion being important prognosticators. The addition of serum markers did not add significant discrimination beyond the clinical presentation.

CONCLUSIONS

The overall outcomes of WFNS IV and V aSAH remain poor, mainly due to the devastating effects of the original haemorrhage. However, in patients selected for aneurysm securement, good outcomes can be achieved in more than half of patients. Age, pre-intervention rebleeding, vasospasm, and CSF diversion are important prognostic factors.

Clinical Reasoning: A 25-Year-Old Woman With Eye Swelling and Headache

Cerebral venous sinus thrombosis (CVST) is uncommon. Risk factors include inherited and acquired factors. Rapid diagnosis and treatment is essential and can help prevent complications, which can include seizures and visual disturbance. A 25-year-old woman with a background history of CVST and intermittent warfarin use presented to the hospital in 2021 with a 3-month history of progressive eye swelling and headache. Her headache was located in the right frontal region and worsened with movement. Her workup was consistent with recurrent CVST and dural arteriovenous fistula. IR-guided embolization of the fistulas and stenting of her sinuses was performed. She was treated with dual antiplatelet therapy and therapeutic tinzaparin. Her symptoms improved markedly over several days, with improvement in headache and visual acuity. This case illustrates the potential for severe complications including visual disturbance in untreated CVST, as well as the importance of a thorough history and examination in aiding the recognition of the condition.

Outcomes with Endovascular Treatment of Patients with M2 Segment MCA Occlusion in the Late Time Window

BACKGROUND AND PURPOSE

Randomized trials in the late window have demonstrated the efficacy and safety of endovascular thrombectomy in large-vessel occlusions. Patients with M2-segment MCA occlusions were excluded from these trials. We compared outcomes with endovascular thrombectomy in patients with M2-versus-M1 occlusions presenting 6-24 hours after symptom onset.

MATERIALS AND METHODS

Analyses were on pooled data from studies enrolling patients with stroke treated with endovascular thrombectomy 6-24 hours after symptom onset. We compared 90-day functional independence (mRS ≤ 2), mortality, symptomatic intracranial hemorrhage, and successful reperfusion (expanded TICI = 2b-3) between patients with M2 and M1 occlusions. The benefit of successful reperfusion was then assessed among patients with M2 occlusion.

RESULTS

Of 461 patients, 367 (79.6%) had M1 occlusions and 94 (20.4%) had M2 occlusions. Patients with M2 occlusions were older and had lower median baseline NIHSS scores. Patients with M2 occlusion were more likely to achieve 90-day functional independence than those with M1 occlusion (adjusted OR = 2.13; 95% CI, 1.25-3.65). There were no significant differences in the proportion of successful reperfusion (82.9% versus 81.1%) or mortality (11.2% versus 17.2%). Symptomatic intracranial hemorrhage risk was lower in patients with M2-versus-M1 occlusions (4.3% versus 12.2%, P = .03). Successful reperfusion was independently associated with functional independence among patients with M2 occlusions (adjusted OR = 2.84; 95% CI, 1.11-7.29).

CONCLUSIONS

In the late time window, patients with M2 occlusions treated with endovascular thrombectomy achieved better clinical outcomes, similar reperfusion, and lower symptomatic intracranial hemorrhage rates compared with patients with M1 occlusion. These results support the safety and benefit of endovascular thrombectomy in patients with M2 occlusions in the late window.

The weekend effect in aneurysmal subarachnoid haemorrhage: a single centre experience and review

Clinical outcomes for patients admitted to hospital during weekend hours have been reported to be poorer than for those admitted during the week. Aneurysmal subarachnoid haemorrhage (aSAH) is a devastating form of haemorrhagic stroke, with a mortality rate greater than 30%. A number of studies have reported higher mortality for patients with aSAH who are admitted during weekend hours. This study evaluates the effect of weekend admission on patients in our unit with aSAH in terms of time to treatment, treatment type, rebleeding rates, functional outcome, and mortality. We analysed a retrospective database of all patients admitted to our tertiary referral centre with aneurysmal subarachnoid haemorrhage between February 2016 and February 2020. Chi-square tests and t-tests were used to compare weekday and weekend demographic and clinical variables. Univariate and multivariate logistic regression analyses were performed to assess for any association between admission during weekend hours and increased neurological morbidity (assessed via Glasgow Outcome Scale at 3 months) and mortality. Of the 571 patients included in this study, 191 were admitted during on-call weekend hours. There were no significant differences found in time to treatment, type of treatment, rebleeding rates, neurological morbidity, or mortality rates between patients admitted during the week and those admitted during weekend hours. Weekend admission was not associated with worsened functional outcome or increased mortality in this cohort. These results suggest that provision of 7-day cover by vascular neurosurgeons and interventional neuroradiologists in high-volume centres could mitigate the weekend effect sometimes reported in the aSAH cohort.

Fallibility of tattooing colonic neoplasia ahead of laparoscopic resection: a retrospective cohort study

INTRODUCTION

Precise geographical localisation of colonic neoplasia is a prerequisite for proper laparoscopic oncological resection. Preoperative endoscopic peri-tumoural tattoo practice is routinely recommended but seldom scrutinised.

METHODS

A retrospective review of recent consecutive patients with preoperative endoscopic lesional tattoo who underwent laparoscopic colonic resection as identified from our prospectively maintained cancer database with supplementary clinical chart and radiological, histological, endoscopic and theatre database/logbook interrogation.

RESULTS

Some 210 patients with 'tattooed' colonic neoplasia were identified, of whom 169 underwent laparoscopic surgery (mean age 68 years, median BMI 27.8kg/m2, male-to-female ratio 95:74). The majority of tumours were malignant (149; 88%), symptomatic (133; 79%) and proximal to the splenic flexure (92; 54%). Inaccurate colonoscopist localisation judgement occurred in 12% of cases, 60% of which were corrected by preoperative staging computed tomography scan. A useful lesional tattoo was absent in 11/169 cases (6.5%) being specifically stated as present in 104 operation notes (61%) and absent in 10 (5.9%). Tumours missing overt peritumoral tattoos intraoperatively were more likely to be smaller, earlier stage and injected longer preoperatively (p=0.006), although half had histological ink staining. Eight lesions missing tattoos were radiologically occult. Four (44%) of these patients had on-table colonoscopy, and five (55%) needed laparotomy (conversion rate 55% vs 23% overall, p<0.005) with one needing a second operation to resect the initially missed target lesion. Mean (range) operative duration and postoperative length of stay of those missing tattoos compared with those with tattoos was 200 (78-300) versus 188 (50-597) min and 15.5 (4-22) versus 12(4-70) days (p>0.05).

CONCLUSIONS

Tattoo in advance of attempting laparoscopic resection is vital for precision cancer surgery especially for radiologically unseen tumours to avoid adverse clinical consequence.

How well do polygenic risk scores identify men at high risk for prostate cancer? Systematic review and meta-analysis

OBJECTIVES

Genome-wide association studies have revealed over 200 genetic susceptibility loci for prostate cancer (PCa). By combining them, polygenic risk scores (PRS) can be generated to predict risk of PCa. We summarize the published evidence and conduct meta-analyses of PRS as a predictor of PCa risk in Caucasian men.

PATIENTS AND METHODS

Data were extracted from 59 studies, with 16 studies including 17 separate analyses used in the main meta-analysis with a total of 20,786 cases and 69,106 controls identified through a systematic search of ten databases. Random effects meta-analysis was used to obtain pooled estimates of area under the receiver-operating characteristic curve (AUC). Meta-regression was used to assess the impact of number of single-nucleotide polymorphisms (SNPs) incorporated in PRS on AUC. Heterogeneity is expressed as I² scores. Publication bias was evaluated using funnel plots and Egger tests.

RESULTS

The ability of PRS to identify men with PCa was modest (pooled AUC 0.63, 95% CI 0.62-0.64) with moderate consistency (I² 64%). Combining PRS with clinical variables increased the pooled AUC to 0.74 (0.68-0.81). Meta-regression showed only negligible increase in AUC for adding incremental SNPs. Despite moderate heterogeneity, publication bias was not evident.

CONCLUSION

Typically, PRS accuracy is comparable to PSA or family history with a pooled AUC value 0.63 indicating mediocre performance for PRS alone.

Prefrontal cortical activation associated with prospective memory while walking around a real-world street environment

Rostral PFC (area 10) activation is common during prospective memory (PM) tasks. But it is not clear what mental processes these activations index. Three candidate explanations from cognitive neuroscience theory are: (i) monitoring of the environment; (ii) spontaneous intention retrieval; (iii) a combination of the two. These explanations make different predictions about the temporal and spatial patterns of activation that would be seen in rostral PFC in naturalistic settings. Accordingly, we plotted functional events in PFC using portable fNIRS while people were carrying out a PM task outside the lab and responding to cues when they were encountered, to decide between these explanations. Nineteen people were asked to walk around a street in London, U.K. and perform various tasks while also remembering to respond to prospective memory (PM) cues when they detected them. The prospective memory cues could be either social (involving greeting a person) or non-social (interacting with a parking meter) in nature. There were also a number of contrast conditions which allowed us to determine activation specifically related to the prospective memory components of the tasks. We found that maintaining both social and non-social intentions was associated with widespread activation within medial and right hemisphere rostral prefrontal cortex (BA 10), in agreement with numerous previous lab-based fMRI studies of prospective memory. In addition, increased activation was found within lateral prefrontal cortex (BA 45 and 46) when people were maintaining a social intention compared to a non-social one. The data were then subjected to a GLM-based method for automatic identification of functional events (AIDE), and the position of the participants at the time of the activation events were located on a map of the physical space. The results showed that the spatial and temporal distribution of these events was not random, but aggregated around areas in which the participants appeared to retrieve their future intentions (i.e., where they saw intentional cues), as well as where they executed them. Functional events were detected most frequently in BA 10 during the PM conditions compared to other regions and tasks. Mobile fNIRS can be used to measure higher cognitive functions of the prefrontal cortex in "real world" situations outside the laboratory in freely ambulant individuals. The addition of a "brain-first" approach to the data permits the experimenter to determine not only when haemodynamic changes occur, but also where the participant was when it happened. This can be extremely valuable when trying to link brain and cognition.

Stroke imaging prior to thrombectomy in the late window: results from a pooled multicentre analysis

BACKGROUND AND PURPOSE

Collateral assessment using CT angiography is a promising modality for selecting patients for endovascular thrombectomy (EVT) in the late window (6-24 hours). The outcome of these patients compared with those selected using perfusion imaging is not clear.

METHODS

We pooled data from seven trials and registries of EVT-treated patients in the late-time window. Patients were classified according to the baseline imaging into collateral imaging alone (collateral cohort) and perfusion plus collateral imaging (perfusion cohort). The primary outcome was the proportion of patients achieving independent 90-day functional outcome (modified Rankin Scale 'mRS' 0-2). We used the propensity score-weighting method to balance important predictors between the cohorts.

RESULTS

In 608 patients, the median onset/last-known-well to emergency arrival time was 8.8 hours and 53.2% had wake-up strokes. Both cohorts had collateral imaging and 379 (62.3%) had perfusion imaging. Independent functional outcome was achieved in 43.1% overall: 168/379 patients (45.5%) in the perfusion cohort versus 94/214 (43.9%) in the collateral cohort (p=0.71). A logistic regression model adjusting for inverse-probability-weighting showed no difference in 90-day mRS score of 0-2 among the perfusion versus collateral cohorts (adjusted OR 1.05, 95% CI 0.69 to 1.59, p=0.83) or in a favourable shift in 90-day mRS (common adjusted OR 1.01, 95% CI 0.69 to 1.47, p=0.97).

CONCLUSION

This pooled analysis of late window EVT showed comparable functional outcomes in patients selected for EVT using collateral imaging alone compared with patients selected using perfusion and collateral imaging.

PROSPERO REGISTRATION NUMBER

CRD42020222003.

Abstract TP155: Sex Differences In Outcome And Workflow Of Endovascular Treatment In Late Window Stroke Patients

Background and Purpose: Sex-related differences exist in many aspects of stroke and were mainly investigated in the early time window with conflicting results. However, data regarding sex disparities in late presenters are scarce. Therefore, we sought to investigate differences in outcomes between women and men treated with endovascular treatment (EVT) in the late time window.

Methods: Analyses were based on the Selection Of Late-window Stroke for Thrombectomy by Imaging Collateral Extent Consortium, which was an individual-patient level analysis of seven trials and registries. Baseline characteristics, functional independence (modified Rankin Scale ≤ 2), mortality, and symptomatic intracranial hemorrhage (sICH) were compared between women and men. Effect of sex on the association between age, successful reperfusion (Thrombolysis in cerebral infarction 2b-3) and outcomes was assessed using multivariable logistic regression with interaction terms.

Results: Among 608 patients treated with EVT, 50.5% were women. Women were older than men by median 4 years and had a lower prevalence of tandem occlusions (14.0% vs. 22.9%). In the subset of patients with available perfusion volumes (n= 195), women had smaller penumbra (median IQR:97 mL [60- 130] vs. 109 mL [73-189]; p= 0.008), and mismatch volumes, (79 mL [49-101] vs. 91 mL [57-158] ; p= 0.02). Pre and intrahospital times were similar between sexes. Outcomes did not differ between women and men, and there was no sex-by-age interaction on functional independence. However, men had higher likelihood of mortality (p interaction = 0.004) and sICH (p interaction = 0.016) with advancing age. Sex did not influence the relation between successful reperfusion and outcomes.

Conclusions: In this multicenter analysis of late presenters treated with EVT, sex was not associated with clinical outcomes. However, sex influenced the association between age and safety outcomes with men experiencing worse outcomes with advancing age.

Abstract 88: Workflow Delays And Outcome Of Endovascular Thrombectomy In The Late Stroke Window:results From A Pooled Multicenter Analysis

Background: Efficient healthcare workflow leads to faster reperfusion and better functional outcomes of stroke in the early-time window. We investigated the impact of care delays on the outcomes of stroke patients treated with endovascular thrombectomy (EVT) in the late window.

Methods: Pooled data from seven randomized clinical trials and registries that only included patients who underwent EVT in the late time window (onset/last known well (LKW) time to imaging time of 6 hours or more) were combined for this analysis. The time intervals from stroke onset to successful reperfusion were analyzed. Logistic regression was used to estimate the likelihood of a functionally independent outcome at 90 days (modified Rankin scale 0-2) for each time interval while adjusting for relevant patients’ characteristics. Negative binomial regression was used to evaluate the relationship between each time interval and the predictors.

Results: 584 patients were included in this analysis. The median age was 70 years (IQR: 21), 293 [50.17%] were females, 298 (53.31%) had wake-up strokes, and the median ASPECTS was 8 (IQR: 2). All patients had CT, and CTA imaging, and 360 (61.64%) underwent perfusion imaging. Successful reperfusion was achieved in 469 (80.45%) patients, and 249 (44.54%) had independent outcomes at 90 days. For every 30 minutes delay, the estimated probability of functional independence decreased by 19% for the emergency department (ED) arrival to imaging time interval, by 25% from groin puncture to end of EVT, and by 12% from ED arrival to end of EVT. Older age and higher NIHSS were associated with longer time from imaging to groin puncture. However, only age was associated with a longer estimated times from stroke onset/LKW to arrival in ED and from stroke onset/LKW to the end of EVT.

Conclusion: Faster in-hospital care is associated with improved functional independence among late-window patients.

Page 1

Sex-Related Differences in Outcomes After Endovascular Treatment of Patients With Late-Window Stroke

BACKGROUND AND PURPOSE

Sex-related differences exist in many aspects of acute stroke and were mainly investigated in the early time window with conflicting results. However, data regarding sex disparities in late presenters are scarce. Therefore, we sought to investigate differences in outcomes between women and men treated with endovascular treatment in the late time window.

METHODS

Analyses were based on the SOLSTICE Consortium (Selection of Late-Window Stroke for Thrombectomy by Imaging Collateral Extent), which was an individual-patient level analysis of seven trials and registries. Baseline characteristics, 90-day functional independence (modified Rankin Scale score ≤2), mortality, and symptomatic intracranial hemorrhage were compared between women and men. Effect of sex on the association of age and successful reperfusion (final Thrombolysis in Cerebral Infarction 2b-3) with outcomes was assessed using multivariable logistic regression adjusted for age, National Institutes of Health Stroke Scale score, Alberta Stroke Program Early CT Score, time from onset to puncture, occlusion location, intravenous thrombolysis, and successful reperfusion, with interaction terms.

RESULTS

Among 608 patients treated with endovascular treatment, 50.5% were women. Women were older than men (median age of 72 versus 68 years, P=0.02) and had a lower prevalence of tandem occlusions (14.0% versus 22.9%, P=0.005). Workflow times were similar between sexes. Adjusted outcomes did not differ between women and men. Functional independence at 90 days was achieved by 127 out of 292 women (43.5%) and 135 out of 291 men (46.4%). Mortality at 90 days (54 [18.5%] versus 48 [16.5%]) and symptomatic intracranial hemorrhage (37 [13.3%] versus 33 [11.6%]) were similar between women and men. There was no sex-by-age interaction on functional outcomes. However, men had higher likelihood of mortality (P_interaction=0.003) and symptomatic intracranial hemorrhage (P_interaction=0.017) with advancing age. Sex did not influence the relation between successful reperfusion and outcomes.

CONCLUSIONS

In this multicenter analysis of late patients treated with endovascular treatment, sex was not associated with functional outcome. However, sex influenced the association between age and safety outcomes, with men experiencing worse outcomes with advancing age.

Correlation between acute ischaemic stroke clot length before mechanical thrombectomy and extracted clot area: Impact of thrombus size on number of passes for clot removal and final recanalization

Introduction

We assessed the correlation between thrombus size before and after mechanical thrombectomy, measured as length by Computed Tomography Angiography/Non-Contrast Computed Tomography (CTA/NCCT) and Extracted Clot Area, ECA, respectively. We also assessed the influence of thrombus size on the number of passes required for clot removal and final recanalization outcome.

Materials and methods

Acute ischaemic stroke (AIS) thrombi retrieved by mechanical thrombectomy from 500 patients and data of clot length by CTA/NCCT were collected from three hospitals in Europe. ECA was obtained by measuring the area of the extracted clot. Non-parametric tests were used for data analysis.

Results

A strong positive correlation was found between clot length on CTA/NCCT and ECA (rho = 0.619,N = 500,P < 0.0001*). Vessel size influences clot length on CTA/NCCT (H2 = 98.6, P < 0.0001*) and ECA (H2 = 105.6,P < 0.0001*), but the significant correlation between CTA/NCCT length and ECA was evident in all vessels. Poorer revascularisation outcome was associated with more passes (H5 = 73.1, P < 0.0001*). More passes were required to remove longer clots (CTA/NCCT; H4 = 31.4, P < 0.0001*; ECA; H4 = 50.2, P < 0.0001*). There was no significant main association between recanalization outcome and length on CTA/NCCT or ECA, but medium sized clots (ECA 20–40 mm²) were associated with least passes and highest revascularisation outcome (N = 500, X² = 16.2, P < 0.0001*).

Conclusion

Clot length on CTA/NCCT strongly correlates with ECA. Occlusion location influences clot size. More passes are associated with poorer revascularisation outcome and bigger clots. The relationship between size and revascularisation outcome is more complex. Clots of medium ECA take less passes to remove and are associated with better recanalization outcome than both smaller and larger clots.

Women in neurointervention, a gender gap? Results of a prospective online survey

BACKGROUND AND PURPOSE

Women's representation in medicine has increased over time yet the proportion of women practicing neurointervention remains low. We conducted an anonymous online survey through which we could explore the gender gap in neurointervention, identify potential issues, difficulties, or obstacles women might face, and evaluate if men encounter similar issues.

METHODS

An online questionnaire was designed in SurveyMonkey®. Invitation to participate was emailed through national and international neurointerventional societies as well as directly through private mailing lists to men and women working in neurointervention. Responses were collected from 10 May 2019 to 10 September 2019.

RESULTS

There were 295 complete responses, 173 (59%) male and 122 (41%) female. Most respondents (83%) fell within age categories 35-60 years, with representation from 40 countries across five continents. In all 95% were working full time, 73% had worked as a neurointerventionalist for >6 years, 77% worked in University-affiliated teaching institutions. Almost half of the respondents indicated no female neurointerventionalist worked in their center. Female respondents were younger and age-adjusted analysis was undertaken. Significantly fewer females than males were married and had children. Significantly fewer females held supervisory roles, held academic titles, and significantly less had a mentor. Females were less satisfied in their careers. More females felt they receive less recognition than colleagues of the opposite sex. Males had a greater proportion of work time dedicated to neurointervention. Similar proportions of both genders experienced bullying in work (40%-47%); however, sexual harassment was more common for females. There were no differences between genders in how they dealt with complications or their effects on mental well-being.

CONCLUSION

There are many potential reasons why women are underrepresented in neurointervention, however, the literature suggests this is not unique to our specialty. Multiple long-term strategies will be necessary to address these issues, some of which are discussed in the article.

Does prior administration of rtPA influence acute ischemic stroke clot composition? Findings from the analysis of clots retrieved with mechanical thrombectomy from the RESTORE registry

BACKGROUND AND PURPOSE

There is still much debate whether bridging-therapy [intravenous thrombolysis (IVT) prior to mechanical thrombectomy (MT)] might be beneficial compared to MT alone. We investigated the effect of IVT on size and histological composition of the clots retrieved from patients undergoing bridging-therapy or MT alone.

METHODS

We collected mechanically extracted thrombi from 1000 acute ischemic stroke (AIS) patients included in RESTORE registry. Patients were grouped according to the administration (or not) of IVT before thrombectomy. Gross photos of each clot were taken and Extracted Clot Area (ECA) was measured using ImageJ software. Martius Scarlett Blue stain was used to characterize the main histological clot components [red blood cells (RBCs), fibrin (FIB), platelets/other (PTL)] and Orbit Image Analysis was used for quantification. Additionally, we calculated the area of each main component by multiplying the component percent by ECA. Chi-squared and Kruskal-Wallis tests were used for statistical analysis.

RESULTS

451 patients (45%) were treated with bridging-therapy while 549 (55%) underwent MT alone. When considering only percent histological composition, we did not find any difference in RBC% (P = 0.895), FIB% (P = 0.458) and PTL% (P = 0.905). However, bridging-therapy clots were significantly smaller than MT-alone clots [32.7 (14.8-64.9) versus 36.8 (20.1-79.8) mm², N = 1000, H1 = 7.679, P = 0.006*]. A further analysis expressing components per clot area showed that clots retrieved from bridging-therapy cases contained less RBCs [13.25 (4.29-32.06) versus 14.97 (4.93-39.80) mm², H1 = 3.637, P = 0.056] and significantly less fibrin [9.10 (4.62-17.98) versus 10.54 (5.57-22.48) mm², H1 = 7.920, P = 0.005*] and platelets/other [5.04 (2.26-11.32) versus 6.54 (2.94-13.79) mm², H1 = 9.380, P = 0.002*] than MT-alone clots.

CONCLUSIONS

Our results suggest that previous IVT administration significantly reduces thrombus size, proportionally releasing all the main histological components.

Improving endovascular access to the target vessel for thrombus aspiration -Use of the wedge device to overcome anatomic hurdles

BACKGROUND AND PURPOSE

Aspiration is a successful technique used in thrombectomy for acute stroke. It is contingent upon the appropriate position of the aspiration catheter, so that it is in contact with the thrombus. However, navigating the craniocervical vasculature is challenging is some patients. The wedge microcatheter (MicroVention®) is designed to reduce the gap between the microcatheter and the SofiaPlus 6F catheter for ease of advancement. The purpose of this study is to describe our initial experience with the wedge microcatheter.

MATERIALS AND METHODS

A retrospective review of 38 consecutive patients in whom the wedge microcatheter was used during thrombectomy was performed to determine whether the wedge microcatheter was successful in delivering the Sofia catheter to the desired location.

RESULTS

We have found this device to be successful in delivering the aspiration catheter to the correct position in 97% (N = 37) of cases. It was used predominantly to pass the origin of branching vessels and also to navigate the tortuous cavernous and petrous segments of the ICA.

CONCLUSION

The wedge microcatheter is a successful tool in delivering the aspiration catheter to the desired vessel for revascularisation.

Timing of treatment of aneurysmal subarachnoid haemorrhage: are the goals set in international guidelines achievable?

BACKGROUND AND AIMS

International guidelines emphasise the importance of securing ruptured cerebral aneurysms within 48-72 h of ictus. We assessed the timing of treatment of patients with aneurysmal subarachnoid haemorrhage (aSAH) referred to a national neurosurgical centre.

MATERIALS AND METHODS

Analysis of a prospective database of patients with aSAH admitted between 1st of February 2016 and 29th of February 2020 was performed. The timing to treatment was expressed in days and analysed in three ways: ictus to treatment, ictus to referral and referral to treatment. ORs with 95% CI were calculated for aneurysm treatment within 24, 48 and 72 h for good grade (WFSN 1-3) and poor grade (WFNS 4-5) cohorts separately.

RESULTS

Of a total of 538 patients with aSAH, the aneurysm was secured in 312 (58%) within 24 h and in 398 (74%) within 48 h of ictus. Securing the aneurysm within 48 h of ictus was achieved in 89% (395/444) of patients who were referred within 24 h of ictus, but in only 3.2% (3/94) who were referred > 24 h after ictus. Poor grade patients (WFNS 4-5) were more likely than good grade patients (WFNS 1-3) to be referred to neurosurgery within 48 h of ictus (OR 22.87, 95% CI 3.14-166.49, p = 0.0020) and for their aneurysm to be secured within 48 h (OR 1.78, 95% CI 1.06-2.98, p = 0.0297) of ictus. Ictus to referral delay was highest in WFNS grade 1 patients.

CONCLUSIONS

In centres with 7 day per week provision of interventional neuroradiology and vascular neurosurgery, the majority of patients with aSAH can be treated within the timeframes recommended by international guidelines and this applies to all grades of aSAH. However, delays still occur in a significant proportion of patients and this particularly applies to delays in presentation and diagnosis in good grade patients.

Per-pass analysis of acute ischemic stroke clots: impact of stroke etiology on extracted clot area and histological composition

Background

Initial studies investigating correlations between stroke etiology and clot composition are conflicting and do not account for clot size as determined by area. Radiological studies have shown that cardioembolic strokes are associated with shorter clot lengths and lower clot burden than non-cardioembolic clots.

Objective

To report the relationship between stroke etiology, extracted clot area, and histological composition at each procedural pass.

Methods

As part of the multi-institutional RESTORE Registry, the Martius Scarlett Blue stained histological composition and extracted clot area of 612 per-pass clots retrieved from 441 patients during mechanical thrombectomy procedures were quantified. Correlations with clinical and procedural details were investigated.

Results

Clot composition varied significantly with procedural passes; clots retrieved in earlier passes had higher red blood cell content (H4=11.644, p=0.020) and larger extracted clot area (H4=10.730, p=0.030). Later passes were associated with significantly higher fibrin (H4=12.935, p=0.012) and platelets/other (H4=15.977, p=0.003) content and smaller extracted clot area. Large artery atherosclerotic (LAA) clots were significantly larger in the extracted clot area and more red blood cell-rich than other etiologies in passes 1–3. Cardioembolic and cryptogenic clots had similar histological composition and extracted clot area across all procedural passes.

Conclusion

LAA clots are larger and associated with a large red blood cell-rich extracted clot area, suggesting soft thrombus material. Cardioembolic clots are smaller in the extracted clot area, consistent in composition and area across passes, and have higher fibrin and platelets/other content than LAA clots, making them stiffer clots. The per-pass histological composition and extracted clot area of cryptogenic clots are similar to those of cardioembolic clots, suggesting similar formation mechanisms.

Fetal medicine specialist experiences of providing a new service of termination of pregnancy for fatal fetal anomaly: a qualitative study

OBJECTIVE

To explore fetal medicine specialists' experiences of caring for parents following a diagnosis of fatal fetal anomaly (FFA) during the implementation of termination of pregnancy (TOP) for FFA for the first time.

DESIGN

Qualitative study.

SETTING

Fetal medicine units in the Republic of Ireland.

POPULATION

Ten fetal medicine specialists from five of the six fetal medicine units.

METHODS

nvivo 12 assisted in the thematic analysis of semi-structured in-depth face-to-face interviews.

MAIN OUTCOME MEASURES

Fetal medicine specialists' experiences of prenatal diagnosis and holistic management of pregnancies complicated by FFA.

RESULTS

Four themes were identified: 'not fatal enough', 'interactions with colleagues', 'supporting pregnant women' and 'internal conflict and emotional challenges'. Fetal medicine specialists feared getting an FFA diagnosis incorrect because of media scrutiny and criminal liability associated with the TOP for FFA legislation. Challenges with the ambiguous and 'restrictive' legislation were identified that 'ostracised' severe anomalies. Teamwork was essential to facilitate opportunities for learning and peer support; however, conflict with colleagues was experienced regarding the diagnosis of FFA, the provision of feticide and palliative care to infants born alive following TOP for FFA. Participants reported challenges implementing TOP for FFA, including the absence of institutional support and 'stretched' resources. Fetal medicine specialists experienced internal conflict and a psychological burden providing TOP for FFA, but did so to 'provide full care for women'.

CONCLUSIONS

Our study identified challenges regarding the suitability of the Irish legislation for TOP for FFA and its rapid introduction into clinical practice. It illustrates the importance of institutional and peer support, as well as the need for supportive management, in the provision of a new service.

TWEETABLE ABSTRACT

The implementation of termination services for fatal fetal anomaly is complex and requires institutional support.

Long-term survival after endoscopic vein harvest for coronary artery bypass grafting

INTRODUCTION

Endoscopic vein harvest is the technique of choice in North America, where it constitutes 80% of conduit harvest for coronary artery bypass grafting. The UK has much lower rates, despite demonstrable perioperative benefits. Concerns about patency and long-term survival are often cited as reasons for poor uptake and evidence in the literature thus far has only addressed mid-term outcomes. We sought to identify the long-term survival of patients undergoing endoscopic vein harvest compared with a contemporaneous cohort of open vein harvest.

MATERIALS AND METHODS

This was a retrospective cohort study of all consecutive patients undergoing isolated coronary artery bypass grafting at a single institution between 2007 and 2017. All-cause long-term mortality was compared using Kaplan-Meier curves and log-rank analysis.

RESULTS

A total of 7,527 patients undergoing coronary artery bypass grafting (1,029 receiving endoscopic vein harvest) were studied. The groups were well matched for preoperative characteristics, except that there were more patients with triple-vessel disease and good left-ventricular function in the endoscopic vein harvest group. There was no statistically significant difference in the long-term survival (p = 0.23). At five years (median follow-up), survival was 86.1% (95% confidence interval 85.3-87.0) in the open vein harvest group compared with 85.5% (95% confidence interval 82.8-88.2) in the endoscopic vein harvest group.

DISCUSSION AND CONCLUSION

Endoscopic vein harvest does not affect long-term survival in an unselected population. The contraindications for minimally invasive vein harvest in coronary artery bypass grafting are increasingly diminishing.

Early repatriation post-thrombectomy: a model of care which maximises the capacity of a stroke network to treat patients with large vessel ischaemic stroke

BACKGROUND AND PURPOSE

Healthcare systems are challenged to provide access to thrombectomy in acute stroke patients. Either the "drip and ship" or "mothership" models result in increased numbers of patients in the endovascular stroke centre (ESC). We describe our approach for a "drip, ship, retrieve and leave" model repatriating patients immediately or within 24 hours of thrombectomy.

METHODS

We included consecutive patients who underwent thrombectomy from January 2016 to June 2018. Patients from local region primary stroke centres (PSC) are immediately repatriated and those from remote region PSCs are admitted for 24 hours before repatriation. Key parameters recorded included clinical, radiological and timeline data as well as 90-day modified Rankin Scale (mRS). Patients who stayed beyond the intended time period in the ESC were analysed.

RESULTS

From January 2016 to June 2018, 435 patients were transferred, with 352 patients in the local region group and 83 in the remote region group. The median NIHSS was 16 with a median ASPECTS of 9. Good functional outcome was seen in 47% of patients with a mortality rate of 19%. The local region group that were repatriated at the intended time period had a 90-day mRS 0-2 of 47% compared with 20% of those admitted to the ESC (P=0.006). Mortality rates were 20% and 27% respectively (P=0.377). The remote region group, repatriated at 24 hours' post-emergency endovascular thrombectomy had 90-day mRS 0-2 of 65% compared with 41% in the group admitted (P=0.042). Mortality rates were 4% and 22% respectively (P=0.007).

CONCLUSION

This model enables the treatment of large numbers of patients with large vessel occlusion acute ischaemic stroke with thrombectomy within a national stroke service and system of care which would not otherwise be facilitated.

Platelet-rich emboli are associated with von Willebrand factor levels and have poorer revascularization outcomes

Background and aims

Platelets and von Willebrand factor (vWF) are key factors in thrombosis and thus are likely key components of acute ischemic stroke (AIS) emboli. We aimed to characterize platelet and vWF levels in AIS emboli and to assess associations between their expression levels and clinical and procedural information.

Materials and method

Histopathological and immunohistochemical analysis of emboli collected as part of the multi-institutional RESTORE registry was performed. The composition of the emboli was quantified using Orbit Image Analysis machine learning software. Correlations between clot components and clinical and procedural information were assessed using the χ2 test.

Results

Ninety-one emboli samples retrieved from 63 patients were analyzed in the study. The mean platelet (CD42b) content of the clots was 33.9% and the mean vWF content of the clots was 29.8%. There was a positive correlation between platelet and vWF levels (ρ=0.564, p<0.001*, n=91). There was an inverse correlation between both platelets and vWF levels and percentage of red blood cells (RBCs) in the emboli (CD42b vs RBC: ρ=−0.535, p<0.001*, n=91; vWF vs RBC: ρ=−0.366, p<0.001*, n=91). Eighty-one percent of patients in the low platelet group had a good revascularization outcome (Thrombolysis in Cerebral Infarction 2c/3) compared with 58% in the high platelet group (χ2=5.856, p=0.016).

Conclusion

Platelet and vWF levels in AIS emboli correlate with each other and both have an inverse relationship with RBC composition. Patients with platelet-rich clots have poorer revascularization outcomes.

Review of external referrals to a regional stroke centre: it is not just about thrombectomy

AIMS

To determine the experience of a regional stroke referral centre of external referrals for endovascular thrombectomy (EVT) in patients with symptoms of acute ischaemic stroke (AIS) and large vessel occlusion (LVO).

MATERIALS AND METHODS

Data were collected prospectively over two 4-month periods (2017-2018) on consecutive external referrals for EVT. Baseline demographics, imaging findings, and key time parameters were recorded. Reasons for not transferring patients and for not performing EVT were recorded. Key time intervals were calculated and compared between the transferred and non-transferred group with and without intracranial occlusion and between the transferred patients who underwent thrombectomy and those who did not.

RESULTS

Two hundred and sixty-two patients were referred. Sixty-one percent (n=159) were accepted and transferred for treatment. Of those transferred, 86% (n=136) had EVT. Fourteen percent (n=23) were unsuitable for EVT on arrival due to no vessel occlusion (48% n=11), poor Alberta Stroke Program Early CT Score (ASPECTS)/established infarct (30%, n=7) haemorrhage (9%, n=2), and clinical recovery (13% n=3). One hundred and three patients (39%) were ineligible for EVT following phone discussion due to absence of intracranial occlusion (59%, n=61), low ASPECTS (22%, n=23), distal occlusion (4%, n=4), low/improving National Institutes of Health Stroke Scale (NIHSS; 10.7%, n=11), and poor modified Rankin Scale (mRS) at baseline (3%, n=3). Patients with LVO but not transferred had longer onset to hospital arrival time compared with those transferred 151.5 versus 91 minutes (p<0.005), with a trend also toward a longer door to CT/CTA 40 minutes versus 30 minutes (p=0.142).

CONCLUSION

These data provide valuable insights into the service provision of a comprehensive stroke network. The present rates of EVT and futile transfers are modest compared to published data. Access to neuroradiology and specialised stroke assessment is crucial to optimise time to treatment.

A Standardized Aspiration-First Approach for Thrombectomy to Increase Speed and Improve Recanalization Rates

BACKGROUND AND PURPOSE

Direct aspiration is a recognized technique for revascularization in large-vessel ischemic strokes. There is ongoing debate regarding its efficacy compared with stent retrievers. Every delay in achieving revascularization and a decrease in reperfusion rates reduces the likelihood of patients achieving functional independence. We propose a standardized setup technique for aspiration-first for all anterior circulation thrombectomy procedures for increasing speed and recanalization rates.

MATERIALS AND METHODS

We analyzed 127 consecutive patients treated by a standardized approach to thrombectomy with an intention to perform aspiration-first compared with 127 consecutive patients treated with a stent retriever-first approach. Key time metrics evaluated included groin to first angiogram, first angiogram to reperfusion, groin to first reperfusion, and length of the procedure. The degree of successful recanalization (TICI 2b-3) and the number of passes were compared between the 2 groups.

RESULTS

In 127 patients who underwent the standardized technique, the median time from groin puncture to first reperfusion was 18 minutes compared with 26 minutes (P < .001). The duration of the procedure was shorter compared with the stent retriever group (26 minutes in the aspiration first group versus 47 minutes, P < .001) and required fewer passes (mean, 2.4 versus 3.1; P < .05). A higher proportion of patients had a TICI score of 2b-3 in the aspiration-first group compared with stent retriever group (96.1% versus 85.8%, P < .005).

CONCLUSIONS

Our study highlights the increasing speed and recanalization rates achieved with fewer passes in a standardized approach to thrombectomy with an intention to attempt aspiration-first. Any attempt to reduce revascularization time and increase successful recanalization should be used.

Assessment of changes in neural activity during acquisition of spatial knowledge using EEG signal classification

OBJECTIVE

This study explored the classification of electroencephalography (EEG) signals to assess changes in neural activity as individuals performed a training task in a virtual environment simulator. Commonly, task behavior and perception are used to assess a trainee's ability to perform a task, however, changes in cognition are not usually measured and could be important to provide a true indication of an individual's level of knowledge or skill.

APPROACH

In this study, 15 participants acquired spatial knowledge via 60 navigation trials (divided into ten blocks) in a novel virtual environment. Time performance, perceived certainty, and EEG signal data were collected.

MAIN RESULTS

A significant increase in alpha power and classification accuracy of EEG data from block 1 against blocks 2-10 was observed and stabilized after block 7, while time performance and perceived certainty measures improved and stabilized after block 5 and 6, respectively.

SIGNIFICANCE

Results suggest that changes in neural activity, which may reflect an increase in cognitive efficiency, could provide additional insight beyond time performance and perceived certainty.

Direct carotid puncture for endovascular thrombectomy in acute ischemic stroke

BACKGROUND

Mechanical thrombectomy is the standard of care for acute ischemic strokes with proximal intracranial occlusion. Arterial access is commonly achieved with femoral artery puncture, although this is not always possible. In this case series, we describe 11 cases of anterior circulation stroke where direct carotid puncture was used to obtain vascular access.

METHODS AND MATERIALS

A review of a prospectively maintained thrombectomy database over a 2-year period (August 2016 - August 2018) was undertaken to identify cases where direct carotid access was performed. CT and angiographic imaging were reviewed. Indications for carotid access, techniques used, technical success of procedure, recanalization rates, procedure-related complications, and patient outcomes were assessed.

RESULTS

Eleven patients out of 498 overall thrombectomy procedures (2.2% thrombectomies) underwent direct carotid access. Median National Institutes of Health Stroke Scale was 20. Seventy three percent of patients received intravenous thrombolysis. The direct carotid approach was performed following the failed femoral approach due to unfavorable aortic arch anatomy, vessel tortuosity, and severe atherosclerotic disease. Direct carotid puncture was successful in 10 patients, and unsuccessful in one. Successful recanalization (TICI 2b-3) was achieved in eight patients. One patient had spontaneously recanalized on angiography. There was failed recanalization in one patient with tandem ICA and M1 occlusion. Carotid access complications included one patient with both neck hematoma and asymptomatic ICA dissection, and one of delayed central retinal artery occlusion.

CONCLUSION

This case series highlights direct carotid puncture as a successful alternative when the femoral approach is not possible, allowing thrombectomy in patients who would otherwise be unsuitable.

Decreasing incidence of subarachnoid hemorrhage

OBJECTIVE

To determine the incidence and trends in subarachnoid hemorrhage in Ireland using data from a national database.

MATERIALS AND METHODS

We performed a retrospective nationwide query of the Irish Hospital In-patient Enquiry System (HIPE). This is a national database of all in-patient activity in acute public hospitals in Ireland. Each HIPE entry records one episode of in-patient care. The study period ranged from 1997 to 2015. Population data was obtained from the Irish Central Statistics Office, and the annual prevalence of smoking from the Irish National Tobacco Control Office. We were therefore able to calculate both crude annual acute subarachnoid hemorrhage (SAH) incidence rates, as well as population-standardized rates, and compared them with trends in the annual smoking rates.

RESULTS

The mean number of SAH cases per year is 549, with 465 cases in 1997 and 517 in 2015 (range: 465-624). The absolute incidence of SAH, therefore, remained relatively stable. Due to population increases over time, the population-adjusted rate of SAH therefore decreased, from 126.9/million people/year in 1997 to 111.5/million people/year in 2015. Nationally, there was a decrease in smoking prevalence, from 31% in 1998 to 19.2% in 2015. There was a statistically significant correlation between decreasing smoking rates and decreasing population-adjusted incidence of SAH (P=<0.0001).

CONCLUSIONS

Our data suggests that the incidence of non-traumatic subarachnoid hemorrhage in our population appears to be decreasing, a decrease which is correlated with decreasing smoking rates. This provides important data both in terms of the epidemiology of SAH, as well as the possible role of public-health interventions in tackling both smoking and declining rates of SAH.

Drip and ship versus direct to endovascular thrombectomy: The impact of treatment times on transport decision-making

INTRODUCTION

In ischaemic stroke care, fast reperfusion is essential for disability free survival. It is unknown if bypassing thrombolysis centres in favour of endovascular thrombectomy (mothership) outweighs transport to the nearest thrombolysis centre for alteplase and then transfer for endovascular thrombectomy (drip-and-ship). We use conditional probability modelling to determine the impact of treatment times on transport decision-making for acute ischaemic stroke.

MATERIALS AND METHODS

Probability of good outcome was modelled using a previously published framework, data from the Irish National Stroke Register, and an endovascular thrombectomy registry at a tertiary referral centre in Ireland. Ireland was divided into 139 regions, transport times between each region and hospital were estimated using Google's Distance Matrix Application Program Interface. Results were mapped using ArcGIS 10.3.

RESULTS

Using current treatment times, drip-and-ship rarely predicts best outcomes. However, if door to needle times are reduced to 30 min, drip-and-ship becomes more favourable; even more so if turnaround time (time from thrombolysis to departure for the endovascular thrombectomy centre) is also reduced. Reducing door to groin puncture times predicts better outcomes with the mothership model.

DISCUSSION

This is the first case study modelling pre-hospital transport for ischaemic stroke utilising real treatment times in a defined geographic area. A moderate improvement in treatment times results in significant predicted changes to the optimisation of a national acute stroke patient transport strategy.

CONCLUSIONS

Modelling patient transport for system-level planning is sensitive to treatment times at both thrombolysis and thrombectomy centres and has important implications for the future planning of thrombectomy services.

Endovascular thrombectomy beyond 12 hours of stroke onset: a stroke network’s experience of late intervention

Background

Selected patients with proximal anterior circulation ischemic stroke who demonstrate limited infarct and sufficient penumbra may benefit from endovascular thrombectomy (EVT) beyond conventional time limits.

Objective

To perform a retrospective review of all cases of EVT performed at our institution for proximal anterior circulation acute ischemic stroke with onset >12 hours.

Materials and methods

Patients were assessed with non-contrast CT brain and multiphase CT angiography, with Alberta Stroke Program Early CT Score (ASPECTS) and collateral grade informing patient selection. Data, including patient demographics, workflow, neuroimaging findings, procedural details, recanalization rates, and 90-day functional outcomes, were collected.

Results

Of the 542 consecutive endovascular thrombectomy cases performed during the study period, 25 (4.6%) were >12 hours from stroke onset. Median age was 69 years (IQR 55–80), median National Institute of Health Stroke Scale score on presentation was 14 (IQR 11–18.5), median ASPECTS was 8 (IQR 8–9), and rate of moderate–good collateral status was 96% (n=24). Median time to groin puncture was 14 hours 40 min (IQR 12 hours 36 min – 16 hours 18 min). Rate of successful recanalization (modified Thrombolysis in Cerebral infarction 2b–3) was 88% (n=22). Rate of functional independence (90-day modified Rankin Scale score 0–2) was 52% (n=13). There were no cases of symptomatic intracranial haemorrhage and 90-day mortality rate was 12% (n=3).

Conclusion

With the use of ASPECTS and collateral grade to guide patient selection, good functional outcome with acceptable safety parameters may be achieved in patients undergoing EVT beyond 12 hours from stroke onset.

Outcomes of endovascular treatment for acute large-vessel ischaemic stroke more than 6 h after symptom onset

BACKGROUND AND OBJECTIVES

Benefit from endovascular thrombectomy (EVT) for large-vessel occlusion (LVO) acute ischaemic stroke (AIS) is well demonstrated. Furthermore, emerging evidence supports efficacy in appropriately selected patients treated beyond current recommendations of 6 h. We evaluated clinical outcomes in patients undergoing late EVT at our institution.

METHODS

Retrospective review of prospectively collected clinical database on 355 patients who underwent EVT for LVO AIS. Data collected consisted of patient demographics, radiological findings and outcome details. Outcomes, including 90-day functional status, recanalization, symptomatic intracranial haemorrhage (sICH) and 90-day mortality, for patients undergoing EVT <6 h, >6 h, and >7.3 h, were compared.

RESULTS

A total of 355 patients underwent EVT for LVO AIS at our institution during the review period, with 74 (21%) patients treated ≥6 h from symptom onset. Successful recanalization was achieved in 285 (80%) patients, with 228 (81%) achieving a mTICI ≥2b in the <6 h group, and 57 (77%) in the >6 h group (P = 0.429). Ninety-day functional independence (mRS 0-2) was achieved in 162 (46%) patients, with 130 (46%) achieving a mRS of 0-2 in the <6 h group, and 32 (43%) in the >6 h group (P = 0.643). No significant differences were found in rates of sICH or 90-day mortality. No significant differences in functional independence, recanalization rates, sICH or mortality were identified in patients treated with EVT >7.3 h compared to <7.3 h.

CONCLUSIONS

In appropriately selected patients, EVT >6 h was associated with comparable outcomes to those treated <6 h. These data support a physiological approach to patient selection.

A novel GLM-based method for the Automatic IDentification of functional Events (AIDE) in fNIRS data recorded in naturalistic environments

Recent technological advances have allowed the development of portable functional Near-Infrared Spectroscopy (fNIRS) devices that can be used to perform neuroimaging in the real-world. However, as real-world experiments are designed to mimic everyday life situations, the identification of event onsets can be extremely challenging and time-consuming. Here, we present a novel analysis method based on the general linear model (GLM) least square fit analysis for the Automatic IDentification of functional Events (or AIDE) directly from real-world fNIRS neuroimaging data. In order to investigate the accuracy and feasibility of this method, as a proof-of-principle we applied the algorithm to (i) synthetic fNIRS data simulating both block-, event-related and mixed-design experiments and (ii) experimental fNIRS data recorded during a conventional lab-based task (involving maths). AIDE was able to recover functional events from simulated fNIRS data with an accuracy of 89%, 97% and 91% for the simulated block-, event-related and mixed-design experiments respectively. For the lab-based experiment, AIDE recovered more than the 66.7% of the functional events from the fNIRS experimental measured data. To illustrate the strength of this method, we then applied AIDE to fNIRS data recorded by a wearable system on one participant during a complex real-world prospective memory experiment conducted outside the lab. As part of the experiment, there were four and six events (actions where participants had to interact with a target) for the two different conditions respectively (condition 1: social-interact with a person; condition 2: non-social-interact with an object). AIDE managed to recover 3/4 events and 3/6 events for conditions 1 and 2 respectively. The identified functional events were then corresponded to behavioural data from the video recordings of the movements and actions of the participant. Our results suggest that "brain-first" rather than "behaviour-first" analysis is possible and that the present method can provide a novel solution to analyse real-world fNIRS data, filling the gap between real-life testing and functional neuroimaging.

ETSON views on R&D priorities for implementation of the 2014 Euratom Directive on safety of nuclear installations

Following the Fukushima-Daiichi accident in 2011, the Council Directive 2014/87/Euratom has reinforced the previous 2009 Directive that had established a Community framework for the safety of nuclear installations. In particular, one new article introduces a high-level EU-wide safety objective of preventing accidents through defence-in-depth and avoiding radioactive releases outside a nuclear installation. For achieving this objective, the research necessary outcomes are mainly a better knowledge of the involved physical phenomena and its capitalization in methodologies and tools such as simulation codes. ETSON, the European Technical Safety Organisation Network, had already identified in its Position Paper in 2011 the main R&D priorities. The present paper underlines that most of these priorities, with a few updates due to progress of knowledge, remain consistent with the objectives of this new Directive. And it illustrates the ETSON involvement through examples of on-going or planned R&D national and international projects.

Management of a large diffuse maxillofacial arteriovenous malformation previously treated with ligation of ipsilateral arterial supply

A 32 year-old male presented with a pulsatile facial mass with palpable thrill and audible bruit. Imaging revealed a very large diffuse left-sided facial arteriovenous malformation with extensive bilateral supply, as well as a previously ligated left external carotid artery. Endovascular treatment was required to control associated hemorrhagic events as well as for palliation and was delivered via the contralateral and ipsilateral collateral supply because of ligation of the direct route to the nidus. In addition, the patient received intravenous bevacizumab and intraarterial bleomycin therapy. Under such circumstances, endovascular embolization remains often the only option when emergent therapy for massive haemorrhage is required. Collaboration and treatment planning with head and neck surgery is imperative and should be performed from the onset, avoiding disastrous ligation of arterial feeders.

Mass Casualty Decontamination in the United States: An Online Survey of Current Practice

Mass casualty decontamination is a public health intervention that would be employed by emergency responders following a chemical, biological, or radiological incident. The decontamination of large numbers of casualties is currently most often performed with water to remove contaminants from the skin surface. An online survey was conducted to explore US fire departments' decontamination practices and their preparedness for responding to incidents involving mass casualty decontamination. Survey respondents were asked to provide details of various aspects of their decontamination procedures, including expected response times to reach casualties, disrobing procedures, approaches to decontamination, characteristics of the decontamination showering process, provision for special populations, and any actions taken following decontamination. The aim of the survey was to identify any differences in the way in which decontamination guidance is implemented across US states. Results revealed that, in line with current guidance, many US fire departments routinely use the "ladder-pipe system" for conducting rapid, gross decontamination of casualties. The survey revealed significant variability in ladder-pipe construction, such as the position and number of fire hoses used. There was also variability in decontamination characteristics, such as water temperature and water pressure, detergent use, and shower duration. The results presented here provide important insights into the ways in which implementation of decontamination guidance can vary between US states. These inconsistencies are thought to reflect established perceived best practices and local adaptation of response plans to address practical and logistical constraints. These outcomes highlight the need for evidence-based national guidelines for conducting mass casualty decontamination.

An exploration of the prevalence and patterns of care for women presenting with mid-trimester loss

BACKGROUND

Mid-trimester loss (MTL) is an area that is poorly defined in the literature and often under reported in clinical practice. The prevalence of MTL in Ireland is uncertain and has a huge impact on the woman, her family and maternity care services.

AIMS

To explore the prevalence and patterns of care for women with MTL in a large Maternity hospital in Ireland.

METHODS

A descriptive, exploratory study was used involving a retrospective chart audit.

RESULTS

220 women presented with MTL over the 3 year data collection period (January 2011-December 2013), giving a rate of 0.8 % of all deliveries. The majority of women had no previous pregnancy losses and were multiparous (i.e., had a previous pregnancy >500 g). The mean gestational age was 17.69 weeks (SD = 2.73). The mean length of hospital stay was 1.89 days. Intra muscular (IM) analgesia was the most commonly (58.5 %) used medication. Follow up hospital care was received in over 78 % of cases. The majority of women were referred the CMS Bereavement and Chaplain services, with a small number (approx. 5 %) referred to the social worker. Over 46.4 % of families availed of the hospital burial service.

CONCLUSIONS

Results suggest the incidence of mid-trimester loss may be slightly lower than the 1 or 2 % of pregnancies reported in the literature. The incidence of mid-trimester loss in multiparous women is approximately twice that of nulliparous women. The referral services offered in the study were utilised by most of the women, as were follow-up clinic appointments.

Neural activity in the suprachiasmatic circadian clock of nocturnal mice anticipating a daytime meal

Circadian rhythms in mammals are regulated by a system of circadian oscillators that includes a light-entrainable pacemaker in the suprachiasmatic nucleus (SCN) and food-entrainable oscillators (FEOs) elsewhere in the brain and body. In nocturnal rodents, the SCN promotes sleep in the day and wake at night, while FEOs promote an active state in anticipation of a predictable daily meal. For nocturnal animals to anticipate a daytime meal, wake-promoting signals from FEOs must compete with sleep-promoting signals from the SCN pacemaker. One hypothesis is that FEOs impose a daily rhythm of inhibition on SCN output that is timed to permit the expression of activity prior to a daytime meal. This hypothesis predicts that SCN activity should decrease prior to the onset of anticipatory activity and remain suppressed through the scheduled mealtime. To assess the hypothesis, neural activity in the SCN of mice anticipating a 4-5-h daily meal in the light period was measured using FOS immunohistochemistry and in vivo multiple unit electrophysiology. SCN FOS, quantified by optical density, was significantly reduced at the expected mealtime in food-anticipating mice with access to a running disk, compared to ad libitum-fed and acutely fasted controls. Group differences were not significant when FOS was quantified by other methods, or in mice without running disks. SCN electrical activity was markedly decreased during locomotion in some mice but increased in others. Changes in either direction were concurrent with locomotion, were not specific to food anticipation, and were not sustained during longer pauses. Reduced FOS indicates a net suppression of SCN activity that may depend on the intensity or duration of locomotion. The timing of changes in SCN activity relative to locomotion suggests that any effect of FEOs on SCN output is mediated indirectly, by feedback from neural or systemic correlates of locomotion.