Influence of Infarct Morphology and Patterns on Cognitive Outcomes After Endovascular Thrombectomy

BACKGROUND

To assess the association of qualitative and quantitative infarct characteristics and 3 cognitive outcome tests, namely the Montreal Cognitive Assessment (MOCA) for mild cognitive impairment, the Boston Naming Test for visual confrontation naming, and the Sunnybrook Neglect Assessment Procedure for neglect, in large vessel occlusion stroke.

METHODS

Secondary observational cohort study using data from the randomized-controlled ESCAPE-NA1 trial (Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke), in which patients with large vessel occlusion undergoing endovascular treatment were randomized to receive either intravenous Nerinetide or placebo. MOCA, Sunnybrook Neglect Assessment Procedure, and 15-item Boston Naming Test were obtained at 90 days. Total infarct volume, gray matter, and white matter infarct volumes were manually measured on 24-hour follow-up imaging. Infarcts were also visually classified as either involving the gray matter only or both the gray and white matter and scattered versus territorial. Associations of infarct variables and cognitive outcomes were analyzed using multivariable ordinal or binary logistic regression models.

RESULTS

Of 1105 patients enrolled in ESCAPE-NA1, 1026 patients with visible infarcts on 24-hour follow-up imaging were included. MOCA and Sunnybrook Neglect Assessment Procedure were available for 706 (68.8%) patients and the 15-item Boston Naming Test was available for 682 (66.5%) patients. Total infarct volume was associated with worse MOCA scores (adjusted common odds ratio per 10 mL increase, 1.05 [95% CI, 1.04-1.06]). After adjusting for baseline variables and total infarct volume, mixed gray and white matter involvement (versus gray matter-only adjusted common odds ratio, 1.92 [95% CI, 1.37-2.69]), white matter infarct volume (adjusted common odds ratio per 10 mL increase 1.36 [95% CI, 1.18-1.58]) and territorial (versus scattered) infarct pattern (adjusted common odds ratio, 1.65 [95% CI, 1.15-2.38]) were associated with worse MOCA scores. Results for Sunnybrook Neglect Assessment Procedure and 15-item Boston Naming Test were similar, except for the territorial infarct pattern, which did not reach statistical significance in multivariable analysis.

CONCLUSIONS

Besides total infarct volume, infarcts that involve the white matter and that show a territorial distribution were associated with worse cognitive outcomes, even after adjusting for total infarct volume.

Symptomatic non-stenotic carotid disease: current challenges and opportunities for diagnosis and treatment

Symptomatic non-stenotic carotid plaques (SyNC) are an under-researched and under-recognized source of stroke. Various imaging markers of non-stenotic carotid plaques that are associated with stroke risk have been identified, but these causal relationships need to be confirmed in additional prospective studies. Currently, there exists neither a standardized SyNC definition nor a dedicated set of imaging protocols, although researchers have started to address these shortcomings. Moreover, many neuroradiologists are still unaware of the condition, and hence do not comment on high-risk plaque features other than stenosis in their reports. Regarding SyNC treatment, scant data exist as to whether and to what extent medical, interventional and surgical treatments could influence the course of the disease; the relative lack of data on the 'natural' history of untreated SyNC makes treatment comparisons difficult. In our opinion, endovascular SyNC treatment represents the most promising treatment option for SyNC, since it allows for targeted elimination of the embolic source, with few systemic side effects and without the need for general anesthesia. However, currently available carotid devices are designed to treat stenotic lesions, and thus are not optimally designed for SyNC. Developing a device specifically tailored to SyNC could be an important step towards establishing endovascular SyNC treatment in clinical practice. In this review, we provide an overview of the current state of evidence with regard to epidemiological, clinical and imaging features of SyNC, propose a SyNC definition based on imaging and clinical features, and outline a possible pathway towards evidence-based SyNC therapies, with a special focus on endovascular SyNC treatment.

Cost-Effectiveness of Late Endovascular Thrombectomy vs. Best Medical Management in a Clinical Trial Setting and Real-World Setting

BACKGROUND AND PURPOSE

To assess cost-effectiveness of late time-window endovascular treatment (EVT) in a clinical trial setting and a "real-world" setting.

METHODS

Data are from the randomized ESCAPE trial and a prospective cohort study (ESCAPE-LATE). Anterior circulation large vessel occlusion patients presenting > 6 hours from last-known-well were included, whereby collateral status was an inclusion criterion for ESCAPE but not ESCAPE-LATE. A Markov state transition model was built to estimate lifetime costs and quality-adjusted life-years (QALYs) for EVT in addition to best medical care vs. best medical care only in a clinical trial setting (comparing ESCAPE-EVT to ESCAPE control arm patients) and a "real-world" setting (comparing ESCAPE-LATE to ESCAPE control arm patients). We performed an unadjusted analysis, using 90-day modified Rankin Scale(mRS) scores as model input and analysis adjusted for baseline factors. Acceptability of EVT was calculated using upper/lower willingness-to-pay thresholds of 100,000 USD/50,000 USD/QALY.

RESULTS

Two-hundred and forty-nine patients were included (ESCAPE-LATE:n = 200, ESCAPE EVT-arm:n = 29, ESCAPE control-arm:n = 20). Late EVT in addition to best medical care was cost effective in the unadjusted analysis both in the clinical trial and real-world setting, with acceptability 96.6%-99.0%. After adjusting for differences in baseline variables between the groups, late EVT was marginally cost effective in the clinical trial setting (acceptability:49.9%-61.6%), but not the "real-world" setting (acceptability:32.9%-42.6%).

CONCLUSION

EVT for LVO-patients presenting beyond 6 hours was cost effective in the clinical trial setting and "real-world" setting, although this was largely related to baseline patient differences favoring the "real-world" EVT group. After adjusting for these, EVT benefit was reduced in the trial setting, and absent in the real-world setting.

Association of Brain Atrophy With Functional Outcome and Recovery Trajectories After Thrombectomy: Post Hoc Analysis of the ESCAPE-NA1 Trial

BACKGROUND AND OBJECTIVES

Brain frailty may impair the ability of acute stroke patients to cope with the injury, irrespective of their chronologic age, resulting in impaired recovery. We aim to investigate the impact of brain atrophy on functional outcome assessed at different time points after endovascular thrombectomy (EVT).

METHODS

In this retrospective post hoc analysis of the ESCAPE-NA1 trial, we analyzed CT imaging data for cortical atrophy by using the GCA scale, including region-specific scales, and subcortical atrophy by using the intercaudate distance to inner table width (CC/IT) ratio. The primary outcome was 90-day mRS (ordinal shift analysis), and the secondary outcome was the mRS score over time. Adjustments were made for age, sex, baseline NIHSS, final infarct volume, stroke laterality, total Fazekas score, and nerinetide-alteplase interaction. Sensitivity analyses were additionally performed in only those patients for whom MRI data were available.

RESULTS

Of 1,102 participants (mean age of 69.5 ± 13.7 years; 554 men), 818 (74%) had GCA = 0, 220 (20%) had GCA = 1, and 64 (6%) had GCA = 2/3. The median CC/IT ratio was 0.12 (IQR0.10-0.15). Cortical atrophy (GCA ≥ 1 vs GCA 0) was associated with worse 90-day mRS (acOR = 1.62 [95% CI 1.22-2.16]; p = 0.001), lower rates of 90-day mRS0-2 (aOR = 0.65 [95% CI 0.45-0.94]; p = 0.022), and higher mortality (aOR = 2.12 [95% CI 1.28-3.5]; p = 0.003), regardless of the region assessed. Subcortical atrophy was associated with worse 90-day mRS (acOR [per 0.01 increase in CC/IT ratio] = 1.07 [95% CI 1.04-1.11]; p < 0.001) and lower rates of 90-day mRS0-2 (aOR = 0.92 [95% CI 0.88-0.97]; p = 0.001). Furthermore, with various degrees of atrophy, we observed heterogeneity in mRS measurements during follow-up: worse mRS scores for higher atrophy grades (p < 0.001). Compared with participants with GCA = 0, the mRS for participants with GCA = 1 was higher at 30 days (adjusted difference = 0.41 [95% CI 0.18-0.65]) and remained worse at 90 days (adjusted difference = 0.72 [95% CI 0.49-0.95]). Similar effects were seen for participants with worse cortical atrophy, regardless of the region assessed, and worse subcortical atrophy. Furthermore, 26/63(41%) and 124/274(45%) patients with severe cortical/subcortical atrophy (GCA 2/3 and highest CC/IT ratio quartile, respectively) achieved good functional outcome (mRS0-2), compared with 539/812(66.4%) with no cortical atrophy and 209/274(76%) in the lowest CC/IT ratio quartile.

DISCUSSION

In this large RCT-derived population, participants with brain atrophy, as visually assessed on acute noncontrast computed tomography imaging, showed less favorable stroke recovery after EVT and worse 90-day functional outcomes compared with participants without brain atrophy. This may support physicians with recovery expectations when planning post-EVT care with patients and their families.

Cost-effectiveness of Endovascular Treatment for Acute Stroke with Large Infarct: A United States Perspective

Background The health economic benefit of endovascular treatment (EVT) in addition to best medical management for acute ischemic stroke with large ischemic core is uncertain. Purpose To assess the cost-effectiveness of EVT plus best medical management versus best medical management alone in treating acute ischemic stroke with large vessel occlusion and a baseline Alberta Stroke Program Early CT Score (ASPECTS) 3-5. Materials and Methods This is a secondary analysis of the randomized RESCUE-Japan LIMIT (Recovery by Endovascular Salvage for Cerebral Ultra-acute Embolism-Japan Large Ischemic Core Trial), with enrollment November 2018 to September 2021, in which the primary outcome was the modified Rankin Scale (mRS) score at 90 days. Participants with a baseline ASPECTS 3-5 (on the basis of noncontrast CT and diffusion-weighted imaging) were randomized 1:1 to receive EVT plus best medical management (n = 100) or best medical management alone (n = 102). The primary outcome of the current study was cost-effectiveness, determined according to the incremental cost-effectiveness ratio (ICER). A decision model consisting of a short-term component (cycle length of 3 months) and a long-term Markov state transition component (cycle length of 1 year) was used to estimate expected lifetime costs and quality-adjusted life-years (QALYs) from health care and societal perspectives in the United States. Upper and lower willingness-to-pay (WTP) thresholds were set at $100 000 and $50 000 per QALY, respectively. A deterministic one-way sensitivity analysis to determine the impact of participant age and a probabilistic sensitivity analysis to assess the impact of parameter uncertainty were conducted. Results A total of 202 participants were included in the study (mean age, 76 years ± 10 [SD]; 112 male). EVT plus best medical management resulted in ICERs of $15 743 (health care perspective) and $19 492 (societal perspective). At the lower and upper WTP thresholds, EVT was cost-effective up to 85 and 90 years (health care perspective) and 84 and 89 years (societal perspective) of age, respectively. When analyzing participants with the largest infarcts (ASPECTS 3) separately, EVT was not cost-effective (ICER, $337 072 [health care perspective] and $383 628 [societal perspective]). Conclusion EVT was cost-effective for participants with an ASPECTS 4-5, but not for those with an ASPECTS 3. ClinicalTrials.gov registration no. NCT03702413 © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Widjaja in this issue.

CT Perfusion Does Not Modify the Effect of Reperfusion in Patients with Acute Ischemic Stroke Undergoing Endovascular Treatment in the ESCAPE-NA1 Trial

BACKGROUND AND PURPOSE

Although reperfusion is associated with improved outcomes in patients with acute ischemic stroke undergoing endovascular treatment, many patients still do poorly. We investigated whether CTP modifies the effect of near-complete reperfusion on clinical outcomes, ie, whether poor clinical outcomes despite near-complete reperfusion can be partly or fully explained by CTP findings.

MATERIALS AND METHODS

Data are from the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial. Admission CTP was processed using RAPID software, generating relative CBF and CBV volume maps at standard thresholds. CTP lesion volumes were compared in patients with-versus-without near-complete reperfusion. Associations between each CTP metric and clinical outcome (90-day mRS) were tested using multivariable logistic regression, adjusted for baseline imaging and clinical variables. Treatment-effect modification was assessed by introducing CTP lesion volume × reperfusion interaction terms in the models.

RESULTS

CTP lesion volumes and reperfusion status were available in 410/1105 patients. CTP lesion volumes were overall larger in patients without near-complete reperfusion, albeit not always statistically significant. Increased CBF <34%, CBV <34%, CBV <38%, and CBV <42% lesion volumes were associated with worse clinical outcome (ordinal mRS) at 90 days. CTP core lesion volumes did not modify the treatment effect of near-complete recanalization on clinical outcome.

CONCLUSIONS

CTP did not modify the effect of near-complete reperfusion on clinical outcomes. Thus, CTP cannot explain why some patients with near-complete reperfusion have poor clinical outcomes.

Influence of geography, stroke timing, and weather conditions on transport and workflow times: Results from a longitudinal 5-year Canadian provincial registry

BACKGROUND

In areas with high population spread such as Saskatchewan, it can be challenging to provide timely endovascular stroke treatment (EVT) to patients living far away from comprehensive stroke centres (CSC). We assessed the association of geography, stroke timing and weather conditions on EVT workflow times and clinical outcomes in Saskatchewan.

METHODS

We included patients who underwent EVT between January 2017 and December 2022 in the province of Saskatchewan, Canada. Univariable and multivariable associations of time from last known well-to-CSC arrival, CSC arrival-to-reperfusion, and 90-day modified Rankin Score (mRS) with driving distance from patient home to CSC, transport mode, outdoor temperature and stroke timing (day & time) were assessed using descriptive statistics and multivariable regression.

RESULTS

Three-hundred-three patients in the province of Saskatchewan underwent EVT between January 2017 and December 2022. Distance from patient home to CSC (beta-coefficient per 10 km increase = 0.02, 95% CI: 0.01-0.03) and direct to CSC transport (beta-coefficient = -0.76, 95% CI = -1.01-[-0.51]) were associated with last known well to CSC arrival time. In-hospital stroke (beta-coefficient = 0.37, 95% CI: 0.16-0.58), direct-to-CSC transfer (beta-coefficient = 0.27, 95% CI: 0.13-0.41) and daytime stroke onset (beta-coefficient = -0.15, 95% CI: -0.28-[-0.04]) were associated with time from CSC arrival to reperfusion. No association with 90-day mRS was seen.

CONCLUSION

Geographic factors and stroke timing were associated with EVT workflow times. However, no association with clinical outcomes was seen, suggesting that EVT patients living remote areas of Saskatchewan have similar benefit from EVT compared to urban areas. Every effort should be made to offer timely EVT to patients from remote areas.

Infarcts in a New Territory: Insights From the ESCAPE-NA1 Trial

BACKGROUND

Infarct in a new territory (INT) is a known complication of endovascular stroke therapy. We assessed the incidence of INT, outcomes after INT, and the impact of concurrent treatments with intravenous thrombolysis and nerinetide.

METHODS

Data are from ESCAPE-NA1 trial (Safety and Efficacy of Nerinetide [NA-1] in Subjects Undergoing Endovascular Thrombectomy for Stroke), a multicenter, international randomized study that assessed the efficacy of intravenous nerinetide in subjects with acute ischemic stroke who underwent endovascular thrombectomy within 12 hours from onset. Concurrent treatment and outcomes were collected as part of the trial protocol. INTs were identified on core lab imaging review of follow-up brain imaging and defined by the presence of infarct in a new vascular territory, outside the baseline target occlusion(s) on follow-up brain imaging (computed tomography or magnetic resonance imaging). INTs were classified by maximum diameter (<2, 2-20, and >20 mm), number, and location. The association between INT and clinical outcomes (modified Rankin Scale and death) was assessed using standard descriptive techniques and adjusted estimates of effect were derived from Poisson regression models.

RESULTS

Among 1092 patients, 103 had INT (9.3%, median age 69.5 years, 49.5% females). There were no differences in baseline characteristics between those with versus without INT. Most INTs (91/103, 88.3%) were not associated with visible occlusions on angiography and 39 out of 103 (37.8%) were >20 mm in maximal diameter. The most common INT territory was the anterior cerebral artery (27.8%). Almost half of the INTs were multiple (46 subjects, 43.5%, range, 2-12). INT was associated with poorer outcomes as compared to no INT on the primary outcome of modified Rankin Scale score of 0 to 2 at 90 days (adjusted risk ratio, 0.71 [95% CI, 0.57-0.89]). Infarct volume in those with INT was greater by a median of 21 cc compared with those without, and there was a greater risk of death as compared to patients with no INT(adjusted risk ratio, 2.15 [95% CI, 1.48-3.13]).

CONCLUSIONS

Infarcts in a new territory are common in individuals undergoing endovascular thrombectomy for acute ischemic stroke and are associated with poorer outcomes. Optimal therapeutic approaches, including technical strategies, to reduce INT represent a new target for incremental quality improvement of endovascular thrombectomy.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02930018.

Association of Iatrogenic Infarcts With Clinical and Cognitive Outcomes in the Evaluating Neuroprotection in Aneurysm Coiling Therapy Trial

BACKGROUND AND OBJECTIVES

Small iatrogenic brain infarcts are often seen on diffusion-weighted MRI (DWI) following surgical or endovascular procedures, but there are few data on their clinical effects. We examined the association of iatrogenic infarcts with outcomes in the ENACT (Evaluating Neuroprotection in Aneurysm Coiling Therapy) randomized controlled trial of nerinetide in patients undergoing endovascular repair of intracranial aneurysms.

METHODS

In this post hoc analysis, we used multivariable models to evaluate the association of the presence and number of iatrogenic infarcts on DWI with neurologic impairment (NIH Stroke Scale [NIHSS]), functional status (modified Rankin Scale [mRS]), and cognitive and neuropsychiatric outcomes (30-minute test battery) at 1-4 days and 30 days postprocedure. We also related infarct number to a z score-derived composite outcome score using quantile regression.

RESULTS

Among 184 patients (median age 56 years [interquartile range (IQR) 50-64]), 124 (67.4%) had postprocedural DWI lesions (median 4, IQR 2-10.5). Nerinetide treatment was associated with fewer iatrogenic infarcts but no overall significant clinical treatment effects. Patients with infarcts had lower Mini-Mental State Examination (MMSE) scores at 2-4 days (median 28 vs 29, adjusted coefficient [acoef] -1.11, 95% CI -1.88 to -0.34, p = 0.005). Higher lesion counts were associated with worse day 1 NIHSS (adjusted odds ratio for NIHSS ≥1: 1.07, 1.02-1.12, p = 0.009), day 2-4 mRS (adjusted common odds ratio [acOR] 1.05, 1.01-1.09, p = 0.005), and day 2-4 MMSE (acoef -0.07, -0.13 to -0.003, p = 0.040) scores. At 30 days, infarct number remained associated with worse mRS (acOR 1.04, 1.01-1.07, p = 0.016) and Hopkins Verbal Learning Test (HVLT) delayed recall scores (acoef -0.21, -0.39 to -0.03, p = 0.020). Patients with infarcts trended towards lower 30-day Digit Symbol Substitution Test (DSST) scores (acoef -3.73, -7.36 to -0.10, p = 0.044). Higher lesion count was associated with worse composite outcome scores at both 1-4 days and 30 days (30-day acoef -0.12, 95% CI -0.21 to -0.03, p = 0.008). Among those with infarcts, day 1 NIHSS and day 2-4 mRS correlated with 30-day NIHSS, DSST, HVLT, and mRS scores, whereas day 2-4 MMSE correlated with 30-day NIHSS and DSST scores (Spearman ρ 0.47, p = 0.001).

DISCUSSION

Iatrogenic brain infarcts were associated with subtle differences in postprocedural (1-4 days) and 30-day outcomes on different measures in this middle-aged cohort, with earlier dysfunction correlating with later differences.

TRIAL REGISTRATION INFORMATION

Clinical trials registration NCT00728182.

Challenges and opportunities in research funding for neurovascular diseases from a clinical researcher's perspective

BACKGROUND & PURPOSE

Neurovascular research is underfunded, imposing substantial challenges on clinical researchers in the field of neurovascular diseases. We explored what physicians perceive to be the greatest challenges with regard to neurovascular research funding, and how they think the funding crisis in neurovascular research could be overcome.

METHODS

We performed an international, multi-disciplinary survey among physicians involved in the medical care of patients with neurovascular diseases. After providing their demographic data, physicians were asked closed-ended questions on their personal opinion regarding challenges in neurovascular research funding, and how these challenges could be overcome. Physicians also described in their own words what they perceived to be the biggest challenges in obtaining funding. Data were analyzed using descriptive statistics and response clustering.

RESULTS

Of 233 participating physicians (70.4% male,82.8% senior staff) from 48 countries, 217(97.4%) perceived the discrepancy between required and available funding to be a problem;172(73.8%) considered it a major problem. High competitiveness (61/118 available free text responses[51.7%]), time-consuming application processes (28/118[23.7%]) and administrative requirements (25/118[21.1%]) were identified as key obstacles. Traditional big funding agencies were perceived to be most capable of closing the neurovascular research funding gap, followed by specialty-specific organizations and industry, while philanthropy and crowdfunding were perceived to be less important.

CONCLUSION

The gap between required and available funding was perceived to be a major problem in neurovascular research, with high competitiveness, time-consuming funding processes and excessive administrative requirements being the key obstacles to obtaining funding. Traditional funding agencies were perceived to be most capable of closing this funding gap.

Abstract 39: Ability Of Radiomics Versus Humans In Predicting First-pass Effect After Endovascular Treatment In The Escape-na1 Trial

Introduction: First-pass effect (FPE), i.e., achieving reperfusion with a single thrombectomy device pass, is associated with better clinical outcomes in patients with acute stroke. FPE is therefore increasingly being used as a marker of device and procedural efficacy. We evaluated the ability of thrombus-based radiomics models to predict FPE in patients undergoing endovascular thrombectomy (EVT) and compare performance to experts and non-radiomics thrombus characteristics.

Methods: Patients with thin-slice non-contrast CT and CT angiography from The Efficacy and Safety of Nerinetide for the Treatment of Acute Ischemic Stroke (ESCAPE-NA1) trial were included. Thrombi were manually segmented on all images. Data was randomly split into a derivation set that included a training and a validation subset and an independent test set. Radiomics features were extracted from the derivation data set. Three expert stroke physicians reviewed baseline imaging and clinical data for the test set. The machine learning (ML) models were compared to the three experts in predicting the primary outcome (FPE) in the test set using area under the receiver operating characteristic curves (AUC-ROC).

Results: A total of 554 patients with available thin-slice images comprised of a derivation set (training subset [n=388, 70%]), validation subset [n=55, 10%]), and a test set (n=111, 20%). FPE was seen in 31.8% in the derivation set and 31.5 % in the test set. AUC of the best radiomics model was 0.74 (95% CI: 0.64, 0.84), which was higher than the mean AUC of the three experts 0.60 (95% CI: 0.50, 0.71) ( P =0.009). Specificity of radiomics was better than the mean specificity of the three experts, 46 of 76 (60%) vs. 35 of 76 (46.4%), P =0.004, whereas sensitivity was not significantly different between radiomics (28 of 35 [79%]) and experts (27 of 35 [77%]). Moreover, radiomics features performed better than non-radiomics features such as thrombus volume and permeability measurements in predicting FPE ( P <0.05).

Conclusion: A radiomics-based ML model of thrombus characteristics on non-contrast CT and CT angiography performs better than experts and non-radiomics image characteristics in predicting FPE in patients with acute stroke treated with EVT.

Abstract WP100: Automatic Large Vessel Occlusion Detection On Computed Tomography Angiography Using A 3D Convolutional Neural Network

Purpose: To validate the performance of a 3D convolutional neural network (CNN) based algorithm i.e. Stroke SENS LVO, in automatically detecting the presence of large vessel occlusions (LVO) on computed tomography angiography (CTA) images of the head.

Method: A total of 400 studies (217 LVO, 183 non-LVO) were used in the analysis. The LVO group includes internal carotid artery (ICA) and m1 segment of the middle cerebral artery (M1-MCA) occlusions; and the non-LVO group includes more distal or posterior cerebral artery occlusions, no occlusions, and hemorrhagic stroke cases. Expert consensus reads were used as reference standard. Performance was evaluated using sensitivity and specificity and corresponding 95% confidence intervals (CI). Additional analysis was performed on several subgroups of interest.

Results: For detecting LVO, the algorithm achieved a sensitivity of 0.894 [0.853, 0.935] and specificity of 0.874 [0.826, 0.922]. Furthermore, sensitivities of 0.857 [0.779, 0.935] on ICA cases (N=77) and 0.914 [0.868, 0.961] on M1-MCA cases (N=140) were noted; similarly, specificities of 0.891 [0.833, 0.949] on hemorrhagic stroke cases (N=110) and 0.849 [0.767, 0.931] on non-LVO-non-hemorrhage cases (N=73) were noted. Similar performances were observed across stratified datasets based on age, sex, scanner manufacturer and slice thickness when compared to the full cohort.

Conclusion: Stroke SENS LVO demonstrated high accuracy in automatic detection of LVO on a large heterogeneous dataset.

Perceived Limits of Endovascular Treatment for Secondary Medium-Vessel-Occlusion Stroke

BACKGROUND AND PURPOSE

Thrombus embolization during mechanical thrombectomy occurs in up to 9% of cases, making secondary medium vessel occlusions of particular interest to neurointerventionalists. We sought to gain insight into the current endovascular treatment approaches for secondary medium vessel occlusion stroke in an international case-based survey because there are currently no clear recommendations for endovascular treatment in these patients.

MATERIALS AND METHODS

Survey participants were presented with 3 cases involving secondary medium vessel occlusions, each consisting of 3 case vignettes with changes in the patient's neurologic status (improvement, no change, unable to assess). Multivariable logistic regression analyses clustered by the respondent's identity were used to assess factors influencing the decision to treat.

RESULTS

In total, 366 physicians (56 women, 308 men, 2 undisclosed) from 44 countries provided 3294 responses to 9 scenarios. Most (54.1%, 1782/3294) were in favor of endovascular treatment. Participants were more likely to treat occlusions in the anterior M2/3 (74.3%; risk ratio = 2.62; 95% CI, 2.27-3.03) or A3 (59.7%; risk ratio = 2.11; 95% CI, 1.83-2.42) segment compared with the M3/4 segment (28.3%; reference). Physicians were less likely to pursue endovascular treatment in patients who showed neurologic improvement than in patients with an unchanged neurologic deficit (49.9% versus 57.0% responses in favor of endovascular treatment, respectively; risk ratio = 0.88, 95% CI, 0.83-0.92). Interventionalists and more experienced physicians were more likely to treat secondary medium vessel occlusions.

CONCLUSIONS

Physicians' willingness to treat secondary medium vessel occlusions endovascularly is limited and varies per occlusion location and change in neurologic status. More evidence on the safety and efficacy of endovascular treatment for secondary medium vessel occlusion stroke is needed.

Patient-Relevant Deficits Dictate Endovascular Thrombectomy Decision-Making in Patients with Low NIHSS Scores with Medium-Vessel Occlusion Stroke

BACKGROUND AND PURPOSE

There is a paucity of evidence regarding the safety of endovascular treatment for patients with acute ischemic stroke due to primary medium-vessel occlusion. The aim of this study was to examine the willingness among stroke physicians to perform endovascular treatment in patients with mild-yet-disabling deficits due to medium-vessel occlusion.

MATERIALS AND METHODS

In an international cross-sectional survey consisting of 7 primary medium-vessel occlusion case scenarios, participants were asked whether the presence of personally disabling deficits would influence their decision-making for endovascular treatment despite the patients having low NIHSS scores (<6). Decision rates were calculated on the basis of physician characteristics. Univariable logistic regression clustered by respondent and scenario identity was performed.

RESULTS

Three hundred sixty-six participants from 44 countries provided 2562 answers to the 7 medium-vessel occlusion scenarios included in this study. In scenarios in which the deficit was relevant to the patient's profession, 56.9% of respondents opted to perform immediate endovascular treatment compared with 41.0% when no information regarding the patient's profession was provided (risk ratio = 1.39, P < .001). The largest effect sizes were seen for female participants (risk ratio = 1.68; 95% CI, 1.35-2.09), participants older than 60 years of age (risk ratio = 1.61; 95% CI, 1.23-2.10), those with more experience in neurointervention (risk ratio = 1.60; 95% CI, 1.24-2.06), and those who personally performed >100 endovascular treatments per year (risk ratio = 1.63; 95% CI, 1.22-2.17).

CONCLUSIONS

The presence of a patient-relevant deficit in low-NIHSS acute ischemic stroke due to medium-vessel occlusion is an important factor for endovascular treatment decision-making. This may have relevance for the conduct and interpretation of low-NIHSS endovascular treatment in randomized trials.

Predictors and clinical impact of infarct progression rate in the ESCAPE-NA1 trial

BACKGROUND

Determining infarct progression rate in acute ischemic stroke (AIS) is important for patient triage, treatment decision-making, and outcome prognostication.

OBJECTIVE

To estimate infarct progression rate in patients with AIS with large vessel occlusion (LVO) and determine its predictors and impact on clinical outcome.

METHODS

Data are from the ESCAPE-NA1 Trial. Patients with AIS with time from last known well to randomization <6 hours and near-complete reperfusion following endovascular treatment were included. Infarct growth rate (mL/h) was estimated by dividing 24 hour infarct volume (measured by non-contrast CT or diffusion-weighted magnetic resonance imaging) by time from last known well to reperfusion. Multivariable linear regression was used to assess the association of patient baseline variables with log-transformed infarct progression rate. The association of infarct progression rate and good outcome (modified Rankin Scale score 0-2) was determined using multivariable logistic regression.

RESULTS

Four hundred and nine patients were included in the study. Median infarct progression rate was 4.74 mL/h (IQR 1.25-14.84). Collateral status (β: -0.81 (95% CI -1.20 to -0.41)), Alberta Stroke Program Early CT Score (ASPECTS, β: -0.34 (95% CI -0.46 to -0.23)), blood glucose(β:0.09 (95% CI 0.02 to 0.16)), and National Institutes of Health Stroke Scale (NIHS score (β: 0.07 (95% CI 0.04 to 0.10)) were associated with log-transformed infarct progression rate. Clinical and imaging baseline variables explained 23% of the variance in infarct progression rate. Infarct progression rate was significantly associated with good outcome (aOR per 1 mL/h increase: 0.96 (95% CI 0.95 to 0.98)).

CONCLUSION

In this sample of patients presenting within the early time window with LVO and near-complete recanalization, infarct progression rate was significantly associated with good outcome. A significant association between ASPECTS, collateral status, blood glucose, and NIHSS score was observed, but baseline imaging and clinical characteristics explained only a small proportion of the interindividual variance. More research on measurable factors affecting infarct growth is needed.

From Three-Months to Five-Years: Sustaining Long-Term Benefits of Endovascular Therapy for Ischemic Stroke

Background and Purpose: During the months and years post-stroke, treatment benefits from endovascular therapy (EVT) may be magnified by disability-related differences in morbidity/mortality or may be eroded by recurrent strokes and non-stroke-related disability/mortality. Understanding the extent to which EVT benefits may be sustained at 5 years, and the factors influencing this outcome, may help us better promote the sustenance of EVT benefits until 5 years post-stroke and beyond.

Methods: In this review, undertaken 5 years after EVT became the standard of care, we searched PubMed and EMBASE to examine the current state of the literature on 5-year post-stroke outcomes, with particular attention to modifiable factors that influence outcomes between 3 months and 5 years post-EVT.

Results: Prospective cohorts and follow-up data from EVT trials indicate that 3-month EVT benefits will likely translate into lower 5-year disability, mortality, institutionalization, and care costs and higher quality of life. However, these group-level data by no means guarantee maintenance of 3-month benefits for individual patients. We identify factors and associated “action items” for stroke teams/systems at three specific levels (medical care, individual psychosocioeconomic, and larger societal/environmental levels) that influence the long-term EVT outcome of a patient. Medical action items include optimizing stroke rehabilitation, clinical follow-up, secondary stroke prevention, infection prevention/control, and post-stroke depression care. Psychosocioeconomic aspects include addressing access to primary care, specialist clinics, and rehabilitation; affordability of healthy lifestyle choices and preventative therapies; and optimization of family/social support and return-to-work options. High-level societal efforts include improving accessibility of public/private spaces and transportation, empowering/engaging persons with disability in society, and investing in treatments/technologies to mitigate consequences of post-stroke disability.

Conclusions: In the longtime horizon from 3 months to 5 years, several factors in the medical and societal spheres could negate EVT benefits. However, many factors can be leveraged to preserve or magnify treatment benefits, with opportunities to share responsibility with widening circles of care around the patient.

Initial Experience With the Trevo NXT Stent Retriever

Background: The application of a new coating to the delivery wire of the Trevo retriever has the potential to improve its handling. We therefore report our initial experience with this new stent retriever for mechanical thrombectomy of large and medium vessel occlusions. Methods: We pooled data of four high-volume European stroke centers over the time period from October 2020 to February 2021. Patients were included in our study if the Trevo NXT stent retriever was used as a first-line device. Primary endpoints were first-pass near-complete or complete reperfusion, defined as mTICI score of ≥2c. Secondary endpoints were final reperfusion, National Institutes of Health Stroke Scale (NIHSS) at 24 h and discharge, device malfunctions, complications during the procedure, and subjective ratings of the interventionalists regarding device functionality. Results: Eighty patients (39 women, mean age 74 ± 14 years) were eligible for our study. Median NIHSS at admission was 15 (IQR, 8-19), and median Alberta Stroke Program Early CT Score at baseline was 9 (IQR, 8-10). In 74 (93%) patients a primary combined approach was used as first-line technique. First-pass near-complete reperfusion was achieved in 43 (54%) and first-pass complete reperfusion in 34 (43%) patients. Final near-complete reperfusion was achieved in 66 (83%) patients after a median of 1.5 (1-3) passes, while final successful reperfusion was observed in 96% of our cases. We observed no device malfunctions. Median NIHSS at discharge was 2 (IQR, 0-5), and 3 patients (4%) suffered a symptomatic intracranial hemorrhage. Conclusions: Based on our initial data, we conclude that the Trevo NXT is an effective and safe tool for mechanical thrombectomy especially when used for combined approaches.

Comparing the Prognostic Impact of Age and Baseline National Institutes of Health Stroke Scale in Acute Stroke due to Large Vessel Occlusion

[Figure: see text].

Is concurrent intravenous alteplase in patients undergoing endovascular treatment for large vessel occlusion stroke cost-effective even if the cost of alteplase is only US$1?

BACKGROUND

The added value of intravenous (IV) alteplase in large vessel occlusion (LVO) stroke over and beyond endovascular treatment (EVT) is controversial. We compared the long-term costs and cost-effectiveness of a direct-to-EVT paradigm in LVO stroke patients presenting directly to the mothership hospital to concurrent EVT and IV alteplase.

METHODS

We used a decision model consisting of a short-run model to analyze costs and functional outcomes within 90 days after the index stroke and a long-run Markov state transition model (cycle length of 12 months) to estimate expected lifetime costs and outcomes. Outcome data were from the DIRECT-MT trial (NCT03469206). Incremental cost-effectiveness ratios and net monetary benefits were calculated and probabilistic sensitivity analysis was performed. Analysis was performed from a healthcare perspective and a societal perspective using both a minimal assumed alteplase cost of US$1 and true alteplase cost.

RESULTS

When assuming a minimal cost of alteplase of $1, EVT with concurrent IV alteplase resulted in incremental lifetime cost of $5664 (healthcare perspective)/$4804 (societal perspective) and a decrement of 0.25 quality-adjusted life years (QALYs) compared with EVT only, indicating dominance of the EVT only approach. Net monetary benefits were consistently higher for EVT only compared with EVT with concurrent alteplase. Probabilistic sensitivity analysis showed increased costs without an increase in QALYs for EVT and concurrent IV alteplase compared with EVT only. Results were even more in favor of EVT when the true cost of alteplase was used for analysis.

CONCLUSION

EVT without concurrent alteplase is the preferred strategy from a health economic standpoint.

Strength of Association between Infarct Volume and Clinical Outcome Depends on the Magnitude of Infarct Size: Results from the ESCAPE-NA1 Trial

BACKGROUND AND PURPOSE

Infarct volume is an important predictor of clinical outcome in acute stroke. We hypothesized that the association of infarct volume and clinical outcome changes with the magnitude of infarct size.

MATERIALS AND METHODS

Data were derived from the Safety and Efficacy of Nerinetide in Subjects Undergoing Endovascular Thrombectomy for Stroke (ESCAPE-NA1) trial, in which patients with acute stroke with large-vessel occlusion were randomized to endovascular treatment plus either nerinetide or a placebo. Infarct volume was manually segmented on 24-hour noncontrast CT or DWI. The relationship between infarct volume and good outcome, defined as mRS 0-2 at 90 days, was plotted. Patients were categorized on the basis of visual grouping at the curve shoulders of the infarct volume/outcome plot. The relationship between infarct volume and adjusted probability of good outcome was fitted with linear or polynomial functions as appropriate in each group.

RESULTS

We included 1099 individuals in the study. Median infarct volume at 24 hours was 24.9 mL (interquartile range [IQR] = 6.6-92.2 mL). On the basis of the infarct volume/outcome plot, 4 infarct volume groups were defined (IQR = 0-15 mL, 15.1-70 mL, 70.1-200 mL, >200 mL). Proportions of good outcome in the 4 groups were 359/431 (83.3%), 219/337 (65.0%), 71/201 (35.3%), and 16/130 (12.3%), respectively. In small infarcts (IQR = 0-15 mL), no relationship with outcome was appreciated. In patients with intermediate infarct volume (IQR = 15-200 mL), there was progressive importance of volume as an outcome predictor. In infarcts of > 200 mL, outcomes were overall poor.

CONCLUSIONS

The relationship between infarct volume and clinical outcome varies nonlinearly with the magnitude of infarct size. Infarct volume was linearly associated with decreased chances of achieving good outcome in patients with moderate-to-large infarcts, but not in those with small infarcts. In very large infarcts, a near-deterministic association with poor outcome was seen.

Endovascular treatment of anterior cerebral artery occlusions

There are limited data on endovascular treatment (EVT) for anterior cerebral artery (ACA) occlusions. This review focuses on aspects related to ACA EVT: ACA anatomy, clinical and imaging findings, prognosis of ACA stroke, and ACA thrombectomy techniques. The ACA anatomy, and the regions supplied by the ACA, are highly variable; frequent anatomical variants include azygos ACA, triplicated ACA and fenestrations of the anterior communicating artery. ACA occlusions can be classified based on occlusion location, their continuity with other vessel occlusions (isolated ACA occlusion vs ACA occlusion as part of a carotid T occlusion) and etiology (primary-spontaneous ACA occlusion, vs secondary-spontaneous or iatrogenic due to clot fragmentation/migration). Symptoms of ACA stroke differ in severity and nature due to large inter-individual variations in territorial ACA blood supply. Generally, ACA strokes are severely disabling, and the typical clinical hallmark is a motor deficit of the contralateral lower extremity. Advanced imaging (CT perfusion, multiphase CT angiography) increases the likelihood of the correct diagnosis of ACA stroke and should be obtained on routine basis.Available data for ACA EVT suggest its feasibility and safety while clinical outcomes are often unfavorable with conservative management. Therefore, the potential benefit of EVT seems obvious. An optimized endovascular approach for ACA thrombectomy comprises the development and use of smaller and softer devices that can be delivered through small microcatheters with an optimized vector of force. Ultimately, generating high-level evidence for ACA EVT from randomized trials remains warranted.

Factors influencing thrombectomy decision making for primary medium vessel occlusion stroke

BACKGROUND

We aimed to explore the preference of stroke physicians to treat patients with primary medium vessel occlusion (MeVO) stroke with immediate endovascular treatment (EVT) in an international cross-sectional survey, as there is no clear guideline recommendation for EVT in these patients.

METHODS

In the survey MeVO-Finding Rationales and Objectifying New Targets for IntervEntional Revascularization in Stroke (MeVO-FRONTIERS), participants were shown four cases of primary MeVOs (six scenarios per case) and asked whether they would treat those patients with EVT. Multivariable logistic regression with clustering by respondent was performed to assess factors influencing the decision to treat. Dominance analysis was performed to assess the influence of factors within the scenarios on decision making.

RESULTS

Overall, 366 participants (56 women; 15%) from 44 countries provided 8784 answers to 24 scenarios. Most physicians (59.2%) would treat patients immediately with EVT. Younger patient age (incidence rate ratio (IRR) 1.24, 99% CI 1.19 to 1.30), higher National Institutes of Health Stroke Scale (NIHSS) score (IRR 1.69, 99% CI 1.57 to 1.82), and small core volume (IRR 1.35, 99% CI 1.24 to 1.46) were positively associated with the decision to treat with EVT. Interventionalists (IRR 1.26, 99% CI 1.01 to 1.56) were more likely to treat patients with MeVO immediately with EVT. In the dominance analysis, factors influencing the decision in favor of EVT were (in order of importance): baseline NIHSS, core volume, alteplase use, patients' age, and occlusion site.

CONCLUSIONS

Most physicians in this survey were interventionalists and would treat patients with MeVO stroke immediately with EVT. This finding supports the need for robust clinical evidence.

Iatrogenic Diffusion-Weighted Imaging Lesions: What Is Their Impact and How Can It Be Measured?

Infarct volume in acute ischemic stroke is closely linked with clinical outcome, with larger infarct volumes being associated with a worse prognosis. Small iatrogenic infarcts, which can occur as a result of surgical or endovascular procedures, are often only seen on diffusion-weighted MR imaging. They often do not lead to any overtly appreciable clinical deficits, hence the term covert or silent infarcts. There is relative paucity of data on the clinical impact of periprocedural hyperintense diffusion-weighted MR imaging lesions, partly because they commonly remain undiagnosed. Clearly, a better understanding of iatrogenic periprocedural diffusion-weighted MR imaging lesions and their clinical significance is needed. In this article, we describe the current limitations of our understanding of the significance of iatrogenic diffusion-weighted MR imaging lesions using exemplary data from the ENACT trial (Safety and Efficacy of NA-1 in Patients With Iatrogenic Stroke After Endovascular Aneurysm Repair) and outline a framework for how to investigate their clinical impact.

Challenges of Outcome Prediction for Acute Stroke Treatment Decisions

Physicians often base their decisions to offer acute stroke therapies to patients around the question of whether the patient will benefit from treatment. This has led to a plethora of attempts at accurate outcome prediction for acute ischemic stroke treatment, which have evolved in complexity over the years. In theory, physicians could eventually use such models to make a prediction about the treatment outcome for a given patient by plugging in a combination of demographic, clinical, laboratory, and imaging variables. In this article, we highlight the importance of considering the limits and nuances of outcome prediction models and their applicability in the clinical setting. From the clinical perspective of decision-making about acute treatment, we argue that it is important to consider 4 main questions about a given prediction model: (1) what outcome is being predicted, (2) what patients contributed to the model, (3) what variables are in the model (considering their quantifiability, knowability at the time of decision-making, and modifiability), and (4) what is the intended purpose of the model? We discuss relevant aspects of these questions, accompanied by clinically relevant examples. By acknowledging the limits of outcome prediction for acute stroke therapies, we can incorporate them into our decision-making more meaningfully, critically examining their contents, outcomes, and intentions before heeding their predictions. By rigorously identifying and optimizing modifiable variables in such models, we can be empowered rather than paralyzed by them.

A review of endovascular treatment for medium vessel occlusion stroke

Medium-vessel occlusions (MeVOs), that is, occlusions of the M2/3 middle cerebral artery, A2/3 anterior cerebral artery, and P2/3 posterior cerebral artery segments, account for 25%-40% of all acute ischemic stroke cases. Clinical outcomes of MeVO stroke with intravenous thrombolysis, which is the current standard of care, are moderate at best. With improving imaging technologies and a growing literature, MeVOs are increasingly recognized as a target for endovascular treatment (EVT). For the time being, there is limited but promising evidence for the safety and efficacy of MeVO EVT, and many neurointerventionists are already routinely offering EVT for MeVO stroke, despite the lack of clear guideline recommendations. In this article, we review the evidence on endovascular treatment for MeVO stroke and summarize the available literature on current imaging strategies, commonly used EVT selection criteria, EVT techniques, and outcome assessment for MeVO stroke.

Rethinking Consent for Stroke Trials in Time-Sensitive Situations: Insights From the COVID-19 Pandemic

Informed consent is a key concept to ensure patient autonomy in clinical trials and routine care. The coronavirus disease 2019 (COVID-19) pandemic has complicated informed consent processes, due to physical distancing precautions and increased physician workload. As such, obtaining timely and adequate patient consent has become a bottleneck for many clinical trials. However, this challenging situation might also present an opportunity to rethink and reappraise our approach to consent in clinical trials. This viewpoint discusses the challenges related to informed consent during the COVID-19 pandemic, whether it could be acceptable to alter current consent processes under these circumstances, and outlines a possible framework with predefined criteria and a system of checks and balances that could allow for alterations of existing consent processes to maximize patient benefit under exceptional circumstances such as the COVID-19 pandemic without undermining patient autonomy.

Secondary Medium Vessel Occlusions: When Clots Move North

Medium vessel occlusions (MeVOs, ie, M2, M3, A2, A3, P2, and P3 segment occlusions) are increasingly recognized as a target for endovascular treatment in acute ischemic stroke. It is important to note that not all MeVOs are equal. Primary MeVOs occur de novo with the underlying mechanisms being very similar to large vessel occlusion strokes. Secondary MeVOs arise from large vessel occlusions through clot migration or fragmentation, either spontaneously or following treatment with intravenous thrombolysis or endovascular treatment. Currently, there are little data on the prevalence, management, and prognosis of acute ischemic stroke due to secondary MeVOs. This type of stroke is, however, likely to become more relevant in the future as indications for endovascular treatment continue to broaden. In this article, we describe different types of secondary MeVOs, imaging findings associated with them, challenges related to the diagnosis of secondary MeVOs, and their potential implications for treatment strategies and clinical outcomes.

Enhancing Education to Avoid Complications in Endovascular Treatment of Unruptured Intracranial Aneurysms: A Neurointerventionalist's Perspective

It is of utmost importance to avoid errors and subsequent complications when performing neurointerventional procedures, particularly when treating low-risk conditions such as unruptured intracranial aneurysms. We used endovascular treatment of unruptured intracranial aneurysms as an example and took a survey-based approach in which we reached out to 233 neurointerventionalists. They were asked what they think are the most important points staff should teach their trainees to avoid errors and subsequent complications in endovascular treatment of unruptured intracranial aneurysms. One hundred twenty-one respondents (51.9%) provided answers in the form of free text responses, which were thematically clustered in an affinity diagram and summarized in this Practice Perspectives. The article is primarily intended for neurointerventional radiology fellows and junior staff and will hopefully provide them the opportunity to learn from the mistakes of their more experienced colleagues.

Endovascular Treatment Decision Making in Patients with Low Baseline ASPECTS: Insights from UNMASK EVT, an International Multidisciplinary Study

BACKGROUND

Current stroke treatment guidelines restrict level 1A recommendations for endovascular therapy to patients with baseline ASPECTS score > 5. However, a recent meta-analysis from the HERMES-group showed treatment benefit in patients with ASPECTS ≤ 5. We aimed to explore how physicians across different specialties and countries approach endovascular treatment decision-making in acute ischemic stroke patients with low baseline ASPECTS.

METHODS

In a multidisciplinary survey, 607 stroke physicians were randomly assigned 10 out of a pool of 22 case-scenarios, 3 of which involved patients with low baseline ASPECTS (A:40-year old with ASPECTS 4, B:33-year old with ASPECTS 2 C:72-year old with ASPECTS 3), otherwise fulfilling all EVT-eligibility criteria. Participants were asked how they would treat the patient A) under their current local resources and B) under assumed ideal conditions, without any external (monetary, policy-related or infrastructural) restraints. Overall and scenario-specific decision rates were calculated. Clustered multivariable logistic regression analysis was used to determine the association of baseline ASPECTS with endovascular treatment-decision.

RESULTS

Baseline ASPECTS score was significantly associated with current (OR:1.09, CI 1.05-1.13) and ideal endovascular treatment-decision (OR:1.12, CI 1.08-1.16). Overall current and ideal treatment decision-rates for the low ASPECTS scenarios were 57.1% and 57.6%. Current and ideal rates for the two younger patients were higher (scenario A:69.9/60.4%, scenario B:60.0/61.5%) compared to the 72-year old patient (41.3/40.2%).

CONCLUSION

Most physicians decided to proceed with endovascular treatment despite low baseline ASPECTS, particularly in younger patients. This may have implications on the design and execution of low ASPECTS randomized trials.

Imaging criteria across pivotal randomized controlled trials for late window thrombectomy patient selection

BACKGROUND

The DAWN and DEFUSE-3 trials showed the benefit of endovascular treatment (EVT) in acute ischemic stroke patients presenting beyond 6 hours from last known well (LKW) and selected by perfusion imaging criteria. The ESCAPE NA1-trial selected patients based on non-contrast CT (NCCT) Alberta Stroke Program Early CT Score (ASPECTS) and multiphase CT angiography (CTA) collateral status. This study compares baseline characteristics, workflow, and outcomes in the EVT arms of DAWN and DEFUSE-3 with late-window patients from the EVT-only arm of ESCAPE-NA1.

METHODS

Aggregate data on baseline characteristics, workflow, reperfusion quality, final infarct volume, and clinical outcomes (modified Rankin Score [mRS] at 90 days) in subjects enrolled in the DAWN and DEFUSE-3 EVT arms were compared with similar data from the ESCAPE-NA1 control arm (EVT-only arm) presenting beyond 6 hours from LKW using descriptive statistics.

RESULTS

Baseline characteristics among late-window patients in the ESCAPE NA1 trial were similar to those in the DAWN and DEFUSE-3 EVT arms. Median time from LKW-to-puncture in subjects enrolled in the ESCAPE NA1 trial was 9 hrs (IQR: 7.5-11 hours) when compared with DAWN (n=107; 12.8 hours, IQR: 10.6-16.7 hours) and DEFUSE-3 (n=92; 11.5 hours, IQR: 9.2-12.8 hours). Median post-treatment infarct-volume was largest in the ESCAPE NA1-patients (47 mL [IQR: 19-146] vs median 8 mL [IQR: 0-48] in the DAWN group and 35 mL [IQR: 18-82] in DEFUSE-3), while % mRS 0-2 at 90 days were similar across the three trials (ESCAPE NA1: 50/111 [45%], DAWN: 52/107 [49%], DEFUSE-3: 41/92 [45%]).

CONCLUSION

Patients enrolled beyond 6 hours from LKW in the ESCAPE-NA1 trial based on NCCT-ASPECTS and mCTA had similar clinical outcomes when compared with patients selected by perfusion imaging in the DAWN and DEFUSE-3 trials.

Considerations for Antiplatelet Management of Carotid Stenting in the Setting of Mechanical Thrombectomy: A Delphi Consensus Statement

BACKGROUND AND PURPOSE

There are only few data and lack of consensus regarding antiplatelet management for carotid stent placement in the setting of endovascular stroke treatment. We aimed to develop a consensus-based algorithm for antiplatelet management in acute ischemic stroke patients undergoing endovascular treatment and simultaneous emergent carotid stent placement.

MATERIALS AND METHODS

We performed a literature search and a modified Delphi approach used Web-based questionnaires that were sent in several iterations to an international multidisciplinary panel of 19 neurointerventionalists from 7 countries. The first round included open-ended questions and formed the basis for subsequent rounds, in which closed-ended questions were used. Participants continuously received feedback on the results from previous rounds. Consensus was defined as agreement of ≥70% for binary questions and agreement of ≥50% for questions with >2 answer options. The results of the Delphi process were then summarized in a draft manuscript that was circulated among the panel members for feedback.

RESULTS

A total of 5 Delphi rounds were performed. Panel members preferred a single intravenous aspirin bolus or, in jurisdictions in which intravenous aspirin is not available, a glycoprotein IIb/IIIa receptor inhibitor as intraprocedural antiplatelet regimen and a combination therapy of oral aspirin and a P2Y12 inhibitor in the postprocedural period. There was no consensus on the role of platelet function testing in the postprocedural period.

CONCLUSIONS

More and better data on antiplatelet management for carotid stent placement in the setting of endovascular treatment are urgently needed. Panel members preferred intravenous aspirin or, alternatively, a glycoprotein IIb/IIIa receptor inhibitor as an intraprocedural antiplatelet agent, followed by a dual oral regimen of aspirin and a P2Y12 inhibitor in the postprocedural period.

Integrating New Staff into Endovascular Stroke-Treatment Workflows in the COVID-19 Pandemic

A health care crisis such as the coronavirus disease 2019 (COVID-19) pandemic requires allocation of hospital staff and resources on short notice. Thus, new and sometimes less experienced team members might join the team to fill in the gaps. This scenario can be particularly challenging in endovascular stroke treatment, which is a highly specialized task that requires seamless cooperation of numerous health care workers across various specialties and professions. This document is intended for stroke teams who face the challenge of integrating new team members into endovascular stroke-treatment workflows during the COVID-19 pandemic or any other global health care emergency. It discusses the key strategies for smooth integration of new stroke-team members in a crisis situation: 1) transfer of key knowledge (simple take-home messages), 2) open communication and a nonjudgmental atmosphere, 3) strategic task assignment, and 4) graded learning and responsibility. While these 4 key principles should generally be followed in endovascular stroke treatment, they become even more important during health care emergencies such as the COVID-19 pandemic, when health care professionals have to take on new and additional roles and responsibilities in challenging working environments for which they were not specifically trained.

Antiplatelet Management for Stent-Assisted Coiling and Flow Diversion of Ruptured Intracranial Aneurysms: A DELPHI Consensus Statement

BACKGROUND AND PURPOSE

There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies.

MATERIALS AND METHODS

The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society.

RESULTS

Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure.

CONCLUSIONS

More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor.

Effect of age and baseline ASPECTS on outcomes in large-vessel occlusion stroke: results from the HERMES collaboration

BACKGROUND

Patient age and baseline Alberta Stroke Program Early CT score (ASPECTS) are both independent predictors of outcome in acute ischemic stroke patients treated with endovascular therapy (EVT). We assessed the combined effect of age and ASEPCTS on clinical outcome in acute ischemic stroke patients with LVO with and without EVT, and EVT treatment effect in different age/ASPECTS subgroups.

METHODS

The HERMES collaboration pooled data of seven randomized controlled trials that tested the efficacy of EVT. Adjusted logistic regression was performed to test for multiplicative interaction of age and ASPECTS with the primary outcome (ordinal mRS) and secondary outcomes (mRS 0-2/0-1/0-3) in the EVT and control arms. Patients were then stratified by age (<75 vs ≥ 75 years) and ASPECTS (0-5/6-7/8-10), and adjusted effect-size estimates for the association of EVT were derived for the six age/ASPECTS subgroups.

RESULTS

1735 patients were included in the analysis. There was no multiplicative interaction between age and ASPECTS on clinical outcomes. In the exploratory subgroup analysis, we found a nominally negative point estimate for the association of EVT with clinical outcome in the ASPECTS 0-5/age ≥75, subgroup (acOR 0.36, 95% CI 0.07 to 1.89). The point estimate for moderate outcome (mRS0-3) nominally favored EVT (aOR 1.24, 95% CI 0.16 to 9.84). In all other subgroups, effect size-estimates consistently favored EVT.

CONCLUSION

There was no multiplicative interaction of age and ASPECTS on clinical outcomes in EVT or control arm patients. Outcomes in patients ≥75 years with ASPECTS 0-5 were poor, irrespective of treatment. Further investigation to define the role of EVT and range of acceptable outcomes in this subgroup is warranted.

MRI Head Coil Malfunction Producing Artifacts Mimicking Malformation of Cortical Development in Pediatric Epilepsy Work-Up

We recently observed a type of MR imaging artifact that consistently mimics an abnormal appearance of the cerebral cortex, leading to initial misinterpretation and repeat scans. The artifact is caused by malfunction of part of the multichannel phased array head coil and is manifested by irregularity of cortical surface and gray-white matter junctions. The presence of such an artifact can be confirmed by assessing the background noise of the MR images and checking the coil element status on the MR imaging operator console.

Impact and prevention of errors in endovascular treatment of unruptured intracranial aneurysms

BACKGROUND

Preventing errors and complications in neurointervention is crucial, particularly in the treatment of unruptured intracranial aneurysms (UIAs), where the natural history is generally benign, and the margin of treatment benefit small. We aimed to investigate how neurointerventionalists perceive the importance and frequency of errors and the resulting complications in endovascular UIA treatment, and which steps could be taken to prevent them.

METHODS

An international multidisciplinary survey was conducted among neurointerventionalists. Participants provided their demographic characteristics and neurointerventional treatment volume. They were asked about their perceptions on the importance and frequency of different errors in endovascular UIA treatment, and which solutions they thought to be most effective in preventing these errors.

RESULTS

Two-hundred-thirty-three neurointerventionalists from 38 countries participated in the survey. Participants identified errors in technical execution as the most common source of complications in endovascular UIA treatment (40.4% thought these errors constituted a relatively or very large proportion of all complication sources), closely followed by errors in decision-making/indication (32.2%) and errors related to management of unexpected events (28.4%). Simulation training was thought to be most effective in reducing technical errors, while cognitive errors were believed to be best minimized by abandoning challenging procedures, more honest discussion of complications and better standardization of procedure steps.

CONCLUSION

Neurointerventionalists perceived both technical and cognitive errors to be important sources of complications in endovascular UIA treatment. Simulation training, a cultural change, higher acceptance of bail-out strategies and better standardization of procedures were perceived to be most effective in preventing these.

Current and future usefulness and potential of virtual simulation in improving outcomes and reducing complications in endovascular treatment of unruptured intracranial aneurysms

BACKGROUND

Simulation training has been used in the aviation industry and surgical specialties for many years, but integration into neurointerventional practice is lagging behind.

OBJECTIVE

To investigate how neurointerventionalists perceive the usefulness and limitations of simulation tools for the treatment of unruptured intracranial aneurysms (UIAs), and to identify simulation applications that were perceived to be most valuable for endovascular UIA treatment.

METHODS

A web-based international multidisciplinary survey was conducted among neurointerventionalists. Participants were asked for their perceptions on the usefulness of current simulation tools and the potential impact of future simulation tools in endovascular UIA treatment. They identified simulation applications that could add most value to endovascular UIA treatment and help to specifically reduce endovascular UIA treatment complications.

RESULTS

233 neurointerventionalists from 38 countries completed the survey, most of whom (157/233 (67.4%)) had access to a simulator as a trainee, but only 15.3% used it frequently. Most participants (117/233 (50.2%)) considered currently available simulation tools relatively useful for endovascular UIA treatment, with greater value for trainees than for staff. Simulation of new devices (147/233 (63.1%)) and virtual practice runs in individual patient anatomy (119/233 (51.1%)) were considered most valuable for reducing endovascular UIA treatment complications.

CONCLUSION

Although neurointerventionalists perceived currently available simulation tools relatively useful, they did not use them regularly during their training. A priori testing of new devices and practice runs in individual patient anatomy in a virtual environment were thought to have the greatest potential for reducing endovascular UIA treatment complications.

The Risk of Stroke and TIA in Nonstenotic Carotid Plaques: A Systematic Review and Meta-Analysis

BACKGROUND

Severe carotid stenosis carries a high risk of stroke. However, the risk of stroke with nonstenotic carotid plaques (<50%) is increasingly recognized.

PURPOSE

We aimed to summarize the risk of TIA or stroke in patients with nonstenotic carotid plaques.

DATA SOURCES

We performed a comprehensive systematic review and meta-analysis in patients with acute ischemic stroke in whom carotid imaging was performed using MEDLINE and the Cochrane Database, including studies published up to December 2019.

STUDY SELECTION

Included studies had >10 patients with <50% carotid plaques on any imaging technique and reported the incidence or recurrence of ischemic stroke/TIA. High-risk plaque features and the risk of progression to stenosis >50% were extracted if reported.

DATA SYNTHESIS

We identified 31 studies reporting on the risk of ipsilateral stroke/TIA in patients with nonstenotic carotid plaques. Twenty-five studies (n = 13,428 participants) reported on first-ever stroke/TIA and 6 studies (n = 122 participants) reported on the recurrence of stroke/TIA.

DATA ANALYSIS

The incidence of first-ever ipsilateral stroke/TIA was 0.5/100 person-years. The risk of recurrent stroke/TIA was 2.6/100 person-years and increased to 4.9/100 person-years if intraplaque hemorrhage was present. The risk of progression to severe stenosis (>50%) was 2.9/100 person-years (8 studies, n = 448 participants).

LIMITATIONS

Included studies showed heterogeneity in reporting stroke etiology, the extent of stroke work-up, imaging modalities, and classification systems used for characterizing carotid stenosis.

CONCLUSIONS

The risk of recurrent stroke/TIA in nonstenotic carotid plaques is not negligible, especially in the presence of high-risk plaque features. Further research is needed to better define the significance of nonstenotic carotid plaques for stroke etiology.

Improving Stroke Care in Times of the COVID-19 Pandemic Through Simulation: Practice Your Protocols!

During the coronavirus disease 2019 (COVID-19) pandemic, infectious disease control is of utmost importance in acute stroke treatment. This is a new situation for most stroke teams that often leads to uncertainty among physicians, nurses, and technicians who are in immediate contact with patients. The situation is made even more complicated by numerous new regulations and protocols that are released in rapid succession. Herein, we are describing our experience with simulation training for COVID-19 stroke treatment protocols. One week of simulation training allowed us to identify numerous latent safety threats and to adjust our institution-specific protocols to mitigate them. It also helped our physicians and nurses to practice relevant tasks and behavioral patterns (eg, proper donning and doffing PPE, where to dispose potentially contaminated equipment) to minimize their infectious exposure and to adapt to the new situation. We therefore strongly encourage other hospitals to adopt simulation training to prepare their medical teams for code strokes during the COVID-19 pandemic.

Evolution of Stroke Thrombectomy Techniques to Optimize First-Pass Complete Reperfusion

Since 2015, endovascular therapy (EVT) has become the standard of care for acute ischemic stroke (AIS) due to large vessel occlusion. It is a safe and highly effective treatment, and its number needed to treat of 2.6 is one of the highest throughout medicine. The ultimate goal when performing EVT is to maximize chances of good outcome through achievement of fast first-pass complete reperfusion, as incomplete and delayed reperfusion increases complication rates and negatively affects outcome. Since EVT has been established as standard of care, new devices have been developed and treatment techniques have been refined. This review provides a brief overview about the rationale for and history of EVT, followed by a detailed step-by-step description of how to perform EVT using the BADDASS (BAlloon guide with large bore Distal access catheter with Dual Aspiration with Stent-retriever as Standard approach), a combined technique, which is in our opinion the safest and most effective way to achieve fast first-pass complete reperfusion. We also discuss treatment strategies for patients with simultaneous high-grade carotid stenosis/pseudoocclusion/occlusion and gaining carotid access in challenging arch anatomy, as these are commonly encountered situations in AIS, and conclude with an outlook on new technologies and future directions of EVT.