Flat-panel Detector Perfusion Imaging and Conventional Multidetector Perfusion Imaging in Patients with Acute Ischemic Stroke : A Comparative Study.

PURPOSE: Flat-panel detector computed tomography (FDCT) is increasingly used in (neuro)interventional angiography suites. This study aimed to compare FDCT perfusion (FDCTP) with conventional multidetector computed tomography perfusion (MDCTP) in patients with acute ischemic stroke. METHODS: In this study, 19 patients with large vessel occlusion in the anterior circulation who had undergone mechanical thrombectomy, baseline MDCTP and pre-interventional FDCTP were included. Hypoperfused tissue volumes were manually segmented on time to maximum (Tmax) and time to peak (TTP) maps based on the maximum visible extent. Absolute and relative thresholds were applied to the maximum visible extent on Tmax and relative cerebral blood flow (rCBF) maps to delineate penumbra volumes and volumes with a high likelihood of irreversible infarcted tissue ("core"). Standard comparative metrics were used to evaluate the performance of FDCTP. RESULTS: Strong correlations and robust agreement were found between manually segmented volumes on MDCTP and FDCTP Tmax maps (r = 0.85, 95% CI 0.65-0.94, p < 0.001; ICC = 0.85, 95% CI 0.69-0.94) and TTP maps (r = 0.91, 95% CI 0.78-0.97, p < 0.001; ICC = 0.90, 95% CI 0.78-0.96); however, direct quantitative comparisons using thresholding showed lower correlations and weaker agreement (MDCTP versus FDCTP Tmax 6 s: r = 0.35, 95% CI -0.13-0.69, p = 0.15; ICC = 0.32, 95% CI 0.07-0.75). Normalization techniques improved results for Tmax maps (r = 0.78, 95% CI 0.50-0.91, p < 0.001; ICC = 0.77, 95% CI 0.55-0.91). Bland-Altman analyses indicated a slight systematic underestimation of FDCTP Tmax maximum visible extent volumes and slight overestimation of FDCTP TTP maximum visible extent volumes compared to MDCTP. CONCLUSION: FDCTP and MDCTP provide qualitatively comparable volumetric results on Tmax and TTP maps; however, direct quantitative measurements of infarct core and hypoperfused tissue volumes showed lower correlations and agreement.

Toward Individual Treatment in Cervical Artery Dissection: Subgroup Analysis of the TREAT-CAD Randomized Trial.

OBJECTIVE: Uncertainty remains regarding antithrombotic treatment in cervical artery dissection. This analysis aimed to explore whether certain patient profiles influence the effects of different types of antithrombotic treatment. METHODS: This was a post hoc exploratory analysis based on the per-protocol dataset from TREAT-CAD (NCT02046460), a randomized controlled trial comparing aspirin to anticoagulation in patients with cervical artery dissection. We explored the potential effects of distinct patient profiles on outcomes in participants treated with either aspirin or anticoagulation. Profiles included (1) presenting with ischemia (no/yes), (2) occlusion of the dissected artery (no/yes), (3) early versus delayed treatment start (median), and (4) intracranial extension of the dissection (no/yes). Outcomes included clinical (stroke, major hemorrhage, death) and magnetic resonance imaging outcomes (new ischemic or hemorrhagic brain lesions) and were assessed for each subgroup in separate logistic models without adjustment for multiple testing. RESULTS: All 173 (100%) per-protocol participants were eligible for the analyses. Participants without occlusion had decreased odds of events when treated with anticoagulation (odds ratio [OR] = 0.28, 95% confidence interval [CI] = 0.07-0.86). This effect was more pronounced in participants presenting with cerebral ischemia (n = 118; OR = 0.16, 95% CI = 0.04-0.55). In the latter, those with early treatment (OR = 0.26, 95% CI = 0.07-0.85) or without intracranial extension of the dissection (OR = 0.34, 95% CI = 0.11-0.97) had decreased odds of events when treated with anticoagulation. INTERPRETATION: Anticoagulation might be preferable in patients with cervical artery dissection presenting with ischemia and no occlusion or no intracranial extension of the dissection. These findings need confirmation. ANN NEUROL 2024.

Simulation of transportation of acute stroke patients in border regions.

Determining the optimal transportation for each stroke patient is critically important to achieve the best possible outcomes. In border regions the next comprehensive stroke center may be just across an international border, but bureaucratic and financial hurdles may prevent a simple transfer to the next stroke center. We hypothesized that in regions close to international borders, patients may benefit from an "open border, closed transfer scenario", meaning that patients in whom a large vessel occlusion (LVO) is detected in the primary stroke center will benefit from a transfer to the nearest stroke center offering endovascular thrombectomy-even if this may be across a national border. We used the Swiss-German-French trinational region as an example for a region with several international borders within close proximity to one another, and compared two feasible scenarios; (a) a "closed borders, open transfer" scenario, where the patient is transported to any center in the same country, (b) an "open border, closed transfer" scenario, where patients are always transported to the nearby primary stroke center first and then to the nearest comprehensive stroke center in either the same or a neighboring country and (c) and "open borders, open transfer" scenario. The outcome of interest was the predicted probability of acute ischemic stroke patients to achieve a good outcome using a conditional probability model which predicts the likelihood of excellent outcome (modified Rankin scale score of 0-1 at 90 days post-stroke) for patients with suspected LVO. Results were modeled in a virtual map from which the ideal transport concept emerged. For an exemplary LVO stroke patient in Germany, the probability of a good outcome was higher in an open border, closed transfer scenario than with closed borders, open transfer (33.1 vs. 30.1%). Moreover, time to EVT would decrease from 232 min in the first scenario to 169 min in an open border, closed transfer scenario. The catchment area of the University Hospital Basel was almost double the size in an open border, closed transfer scenario compared to closed borders (1674 km2 vs. 2897 km2) and would receive transfers from 3 primary stroke centers in other countries (2 in Germany and 1 in France). Stroke patients showed a higher likelihood of good outcome in the "open border" scenarios without transfer restrictions to a specific healthcare system. This probably has implications for stroke treatment in all border regions where EVT eligible stroke patients may benefit from transport to the closest EVT capable center whenever possible, regardless of whether this hospital is located in the same or a neighboring country/jurisdiction.

Initial Experience with the Solitaire X 3 mm Stent Retriever for the Treatment of Distal Medium Vessel Occlusions.

Endovascular therapy (EVT) is the standard treatment for ischemic stroke caused by a large vessel occlusion (LVO). The effectiveness of EVT for distal medium vessel occlusions (MDVOs) is still uncertain, but newer, smaller devices show potential for EVT in MDVOs. The new Solitaire X 3 mm device offers a treatment option for MDVOs. Our study encompassed consecutive cases of primary and secondary MDVOs treated with the Solitaire X 3 mm stent-retriever as first-line EVT device between January and December 2022 at 12 European stroke centers. The primary endpoint was a first-pass near-complete or complete reperfusion, defined as a modified treatment in cerebral infarction (mTICI) score of 2c/3. Additionally, we examined reperfusion results, National Institutes of Health Stroke Scale (NIHSS) scores at 24 h and discharge, device malfunctions, complications and procedural technical parameters. Sixty-eight patients (38 women, mean age 72 ± 14 years) were included in our study. Median NIHSS at admission was 11 (IQR 6-16). In 53 (78%) cases, a primary combined approach was used as the frontline technique. Among all enrolled patients, first-pass mTICI 2c/3 was achieved in 22 (32%) and final mTICI 2c/3 in 46 (67.6%) patients after a median of 1.5 (IQR 1-2) passes. Final reperfusion mTICI 2b/3 was observed in 89.7% of our cases. We observed no device malfunctions. Median NIHSS at discharge was 2 (IQR 0-4), and no symptomatic intracranial hemorrhages were reported. Based on our analysis, the utilization of the Solitaire X 3 mm device appears to be both effective and safe for performing EVT in cases of MDVO stroke.

Current Status of and Future Developments in Acute Stroke Management.

Stroke treatment has advanced rapidly over the last few years [...].

Incidence and outcome of perforations during medium vessel occlusion compared with large vessel occlusion thrombectomy.

BACKGROUND: Vessel perforation during thrombectomy is a severe complication and is hypothesized to be more frequent during medium vessel occlusion (MeVO) thrombectomy. The aim of this study was to compare the incidence and outcome of patients with perforation during MeVO and large vessel occlusion (LVO) thrombectomy and to report on the procedural steps that led to perforation. METHODS: In this multicenter retrospective cohort study, data of consecutive patients with vessel perforation during thrombectomy between January 1, 2015 and September 30, 2022 were collected. The primary outcomes were independent functional outcome (ie, modified Rankin Scale 0-2) and all-cause mortality at 90 days. Binomial test, chi-squared test and t-test for unpaired samples were used for statistical analysis. RESULTS: During 25 769 thrombectomies (5124 MeVO, 20 645 LVO) in 25 stroke centers, perforation occurred in 335 patients (1.3%; mean age 72 years, 62% female). Perforation occurred more often in MeVO thrombectomy (2.4%) than in LVO thrombectomy (1.0%, p<0.001). More MeVO than LVO patients with perforation achieved functional independence at 3 months (25.7% vs 10.9%, p=0.001). All-cause mortality did not differ between groups (overall 51.6%). Navigation beyond the occlusion and retraction of stent retriever/aspiration catheter were the two most common procedural steps that led to perforation. CONCLUSIONS: In our cohort, perforation was approximately twice as frequent in MeVO than in LVO thrombectomy. Efforts to optimize the procedure may focus on navigation beyond the occlusion site and retraction of stent retriever/aspiration catheter. Further research is necessary in order to identify thrombectomy candidates at high risk of intraprocedural perforation and to provide data on the effectiveness of endovascular countermeasures.

Endovascular Treatment and Peri-interventional Management of Ruptured Cerebrovascular Lesions During Pregnancy : Case Series and Case-based Systematic Review.

PURPOSE: Hemorrhagic stroke, particularly occurring from ruptured cerebrovascular malformations, is responsible for 5-12% of all maternal deaths during pregnancy and the puerperium. Whether endovascular treatment is feasible and safe for both the mother and the fetus, is still a matter of debate. The main objective of this case series and systematic review was to share our multi-institutional experience and to assess the feasibility and safety of endovascular treatment during pregnancy, as well as the corresponding maternal and fetal outcomes based on currently available evidence. METHODS: We report a case series of 12 pregnant women presenting with hemorrhagic stroke from ruptured cerebrovascular arteriovenous malformations or aneurysms who underwent endovascular treatment prior to delivery. A systematic literature review of pregnant patients with endovascular treated cerebrovascular malformations, published between 1995 and 2022, was performed. Clinical patient information, detailed treatment strategies, maternal and fetal outcomes as well as information on the delivery were collected and assessed. RESULTS: In most patients the course was uneventful and an excellent outcome without significant neurological deficits (mRS ≤ 1) was achieved. Furthermore, the maternal outcome was not worse compared to the general population who underwent endovascular treatment of ruptured vascular brain lesions. Also, in most cases a healthy fetus was born. CONCLUSION: Endovascular treatment of ruptured cerebrovascular malformations during pregnancy is safe and feasible regarding both aspects, the maternal and fetal outcomes. Still, a stronger knowledge base is needed to correctly approach future cases of intracranial hemorrhage in the pregnant population.

Comparing treatment outcomes of various intracranial bifurcation aneurysms locations using the Woven EndoBridge (WEB) device.

BACKGROUND: The Woven EndoBridge (WEB) device has Food and Drug Administration approval for treatment of wide-necked intracranial bifurcation aneurysms. The WEB device has been shown to result in adequate occlusion in bifurcation aneurysms overall, but its usefulness in the individual bifurcation locations has been evaluated separately only in few case series, which were limited by small sample sizes. OBJECTIVE: To compare angiographic and clinical outcomes after treatment of bifurcation aneurysms at various locations, including anterior communicating artery (AComA), anterior cerebral artery (ACA) bifurcation distal to AComA, basilar tip, internal carotid artery (ICA) bifurcation, and middle cerebral artery (MCA) bifurcation aneurysms using the WEB device. METHODS: A retrospective cohort analysis was conducted at 22 academic institutions worldwide to compare treatment outcomes of patients with intracranial bifurcation aneurysms using the WEB device. Data include patient and aneurysm characteristics, procedural details, angiographic and functional outcomes, and complications. RESULTS: A total of 572 aneurysms were included. MCA (36%), AComA (35.7%), and basilar tip (18.9%) aneurysms were most common. The rate of adequate aneurysm occlusion was significantly higher for basilar tip (91.6%) and ICA bifurcation (96.7%) aneurysms and lower for ACA bifurcation (71.4%) and AComA (80.6%) aneurysms (p=0.04). CONCLUSION: To our knowledge, this is the most extensive study to date that compares the treatment of different intracranial bifurcation aneurysms using the WEB device. Basilar tip and ICA bifurcation aneurysms showed significantly higher rates of aneurysm occlusion than other locations.

Circadian rhythm of ischaemic core progression in human stroke.

INTRODUCTION: Experimental stroke studies suggest an influence of the time of day of stroke onset on infarct progression. Whether this holds true after human stroke is unknown, but would have implications for the design of randomised controlled trials, especially those on neuroprotection. METHODS: We pooled data from 583 patients with anterior large-vessel occlusion stroke from three prospectively recruited cohorts. Ischaemic core and penumbra volumes were determined with CT perfusion using automated thresholds. Core growth was calculated as the ratio of core volume and onset-to-imaging time. To determine circadian rhythmicity, we applied multivariable linear and sinusoidal regression analysis adjusting for potential baseline confounders. RESULTS: Patients with symptom onset at night showed larger ischaemic core volumes on admission compared with patients with onset during the day (median, 40.2 mL vs 33.8 mL), also in adjusted analyses (p=0.008). Sinusoidal analysis indicated a peak of core volumes with onset at 11pm. Core growth was faster at night compared with day onset (adjusted p=0.01), especially for shorter onset-to-imaging times. In contrast, penumbra volumes did not change across the 24-hour cycle. DISCUSSION: These results suggest that human infarct progression varies across the 24-hour cycle with potential implications for the design and interpretation of neuroprotection trials.

Computed tomography hypoperfusion-hypodensity mismatch vs. automated perfusion mismatch to identify stroke patients eligible for thrombolysis.

Background and purpose: Automated perfusion imaging can detect stroke patients with unknown time of symptom onset who are eligible for thrombolysis. However, the availability of this technique is limited. We, therefore, established the novel concept of computed tomography (CT) hypoperfusion-hypodensity mismatch, i.e., an ischemic core lesion visible on cerebral perfusion CT without visible hypodensity in the corresponding native cerebral CT. We compared both methods regarding their accuracy in identifying patients suitable for thrombolysis. Methods: In a retrospective analysis of the MissPerfeCT observational cohort study, patients were classified as suitable or not for thrombolysis based on established time window and imaging criteria. We calculated predictive values for hypoperfusion-hypodensity mismatch and automated perfusion imaging to compare accuracy in the identification of patients suitable for thrombolysis. Results: Of 247 patients, 219 (88.7%) were eligible for thrombolysis and 28 (11.3%) were not eligible for thrombolysis. Of 197 patients who were within 4.5 h of symptom onset, 190 (96.4%) were identified by hypoperfusion-hypodensity mismatch and 88 (44.7%) by automated perfusion mismatch (p < 0.001). Of 22 patients who were beyond 4.5 h of symptom onset but were eligible for thrombolysis, 5 patients (22.7%) were identified by hypoperfusion-hypodensity mismatch. Predictive values for the hypoperfusion-hypodensity mismatch vs. automated perfusion mismatch were as follows: sensitivity, 89.0% vs. 50.2%; specificity, 71.4% vs. 100.0%; positive predictive value, 96.1% vs. 100.0%; and negative predictive value, 45.5% vs. 20.4%. Conclusion: The novel method of hypoperfusion-hypodensity mismatch can identify patients suitable for thrombolysis with higher sensitivity and lower specificity than established techniques. Using this simple method might therefore increase the proportion of patients treated with thrombolysis without the use of special automated software.The MissPerfeCT study is a retrospective observational multicenter cohort study and is registered with clinicaltrials.gov (NCT04277728).

Simplified Assessment of Lesion Water Uptake for Identification of Patients within 4.5 Hours of Stroke Onset: An Analysis of the MissPerfeCT Study.

BACKGROUND AND PURPOSE: Many patients with stroke cannot receive intravenous thrombolysis because the time of symptom onset is unknown. We tested whether a simple method of computed tomography (CT)-based quantification of water uptake in the ischemic tissue can identify patients with stroke onset within 4.5 hours. METHODS: This retrospective analysis of the MissPerfeCT study (August 2009 to November 2017) includes consecutive patients with known onset of symptoms from seven tertiary stroke centers. We developed a simplified algorithm based on region of interest (ROI) measurements to quantify water uptake of the ischemic lesion and thereby quantify time of symptom onset within and beyond 4.5 hours. Perfusion CT was used to identify ischemic brain tissue, and its density was measured in non-contrast CT and related to the density of the corresponding area of the contralateral hemisphere to quantify lesion water uptake. RESULTS: Of 263 patients, 204 (77.6%) had CT within 4.5 hours. Water uptake was significantly lower in patients with stroke onset within (6.7%; 95% confidence interval [CI], 6.0% to 7.4%) compared to beyond 4.5 hours (12.7%; 95% CI, 10.7% to 14.7%). The area under the curve for distinguishing these patient groups according to percentage water uptake was 0.744 with an optimal cut-off value of 9.5%. According to this cut-off the positive predictive value was 88.8%, sensitivity was 73.5%, specificity 67.8%, negative predictive value was 42.6%. CONCLUSIONS: Ischemic stroke patients with unknown time of symptom onset can be identified as being within a timeframe of 4.5 hours using a ROI-based method to assess water uptake on admission non-contrast head CT.

European Stroke Organisation guidelines on treatment of patients with intracranial atherosclerotic disease.

The aim of the present European Stroke Organisation guideline is to provide clinically useful evidence-based recommendations on the management of patients with intracranial atherosclerotic disease (ICAD). The guidelines were prepared following the Standard Operational Procedure of the European Stroke Organisation guidelines and according to GRADE methodology. ICAD represents a major cause of ischemic stroke worldwide, and patients affected by this condition are exposed to a high risk for future strokes and other major cardiovascular events, despite best medical therapy available. We identified 11 relevant clinical problems affecting ICAD patients and formulated the corresponding Population Intervention Comparator Outcomes (PICO) questions. The first two questions refer to the asymptomatic stage of the disease, which is being increasingly detected thanks to the routine use of noninvasive vascular imaging. We were not able to provide evidence-based recommendations regarding the optimal detection strategy and management of asymptomatic ICAD, and further research in the field is encouraged as subclinical ICAD may represent a big opportunity to improve primary stroke prevention. The second block of PICOs (3-5) is dedicated to the management of acute large vessel occlusion (LVO) ischemic stroke caused by ICAD, a clinical presentation of this disease that is becoming increasingly relevant and problematic, since it is associated with more refractory endovascular reperfusion procedures. An operational definition of probable ICAD-related LVO is proposed in the guideline. Despite the challenging context, no dedicated randomized clinical trials (RCTs) were identified, and therefore the guideline can only provide with suggestions derived from observational studies and our expert consensus, such as the escalated use of glycoprotein IIb-IIIa inhibitors and angioplasty/stenting in cases of refractory thrombectomies due to underlying ICAD. The last block of PICOs is devoted to the secondary prevention of patients with symptomatic ICAD. Moderate-level evidence was found to recommend against the use of oral anticoagulation as preferred antithrombotic drug, in favor of antiplatelets. Low-level evidence based our recommendation in favor of double antiplatelet as the antithrombotic treatment of choice in symptomatic ICAD patients, which we suggest to maintain during 90 days as per our expert consensus. Endovascular therapy with intracranial angioplasty and or stenting is not recommended as a treatment of first choice in high-grade symptomatic ICAD (moderate-level evidence). Regarding neurosurgical interventions, the available evidence does not support their use as front line therapies in patients with high-grade ICAD. There is not enough evidence as to provide any specific recommendation regarding the use of remote ischemic conditioning in ICAD patients, and further RCTs are needed to shed light on the utility of this promising therapy. Finally, we dedicate the last PICO to the importance of aggressive vascular risk factor management in ICAD, although the evidence derived from RCTs specifically addressing this question is still scarce.

Multicenter Study for the Treatment of Sidewall versus Bifurcation Intracranial Aneurysms with Use of Woven EndoBridge (WEB).

Background The Woven EndoBridge (WEB) device was explicitly designed for wide-neck intracranial bifurcation aneurysms. Small-scale reports have evaluated the off-label use of WEB devices for the treatment of sidewall aneurysms, with promising outcomes. Purpose To compare the angiographic and clinical outcomes of the WEB device for the treatment of sidewall aneurysms compared with the treatment of bifurcation aneurysms. Materials and Methods A retrospective review of the WorldWideWEB Consortium, a synthesis of retrospective databases spanning from January 2011 to June 2021 at 22 academic institutions in North America, South America, and Europe, was performed to identify patients with intracranial aneurysms treated with the WEB device. Characteristics and outcomes were compared between bifurcation and sidewall aneurysms. Propensity score matching (PSM) was used to match by age, pretreatment ordinal modified Rankin Scale score, ruptured aneurysms, location of aneurysm, multiple aneurysms, prior treatment, neck, height, dome width, daughter sac, and incorporated branch. Results A total of 683 intracranial aneurysms were treated using the WEB device in 671 patients (median age, 61 years [IQR, 53-68 years]; male-to-female ratio, 1:2.5). Of those, 572 were bifurcation aneurysms and 111 were sidewall aneurysms. PSM was performed, resulting in 91 bifurcation and sidewall aneurysms pairs. No significant difference was observed in occlusion status at last follow-up, deployment success, or complication rates between the two groups. Conclusion No significantly different outcomes were observed following the off-label use of the Woven EndoBridge, or WEB, device for treatment of sidewall aneurysms compared with bifurcation aneurysms. The correct characterization of the sidewall aneurysm location, neck angle, and size is crucial for successful treatment and lower retreatment rate. © RSNA, 2022 See also the editorial by Hetts in this issue.

Utilization of Artificial Intelligence-based Intracranial Hemorrhage Detection on Emergent Noncontrast CT Images in Clinical Workflow.

Authors implemented an artificial intelligence (AI)-based detection tool for intracranial hemorrhage (ICH) on noncontrast CT images into an emergent workflow, evaluated its diagnostic performance, and assessed clinical workflow metrics compared with pre-AI implementation. The finalized radiology report constituted the ground truth for the analysis, and CT examinations (n = 4450) before and after implementation were retrieved using various keywords for ICH. Diagnostic performance was assessed, and mean values with their respective 95% CIs were reported to compare workflow metrics (report turnaround time, communication time of a finding, consultation time of another specialty, and turnaround time in the emergency department). Although practicable diagnostic performance was observed for overall ICH detection with 93.0% diagnostic accuracy, 87.2% sensitivity, and 97.8% negative predictive value, the tool yielded lower detection rates for specific subtypes of ICH (eg, 69.2% [74 of 107] for subdural hemorrhage and 77.4% [24 of 31] for acute subarachnoid hemorrhage). Common false-positive findings included postoperative and postischemic defects (23.6%, 37 of 157), artifacts (19.7%, 31 of 157), and tumors (15.3%, 24 of 157). Although workflow metrics such as communicating a critical finding (70 minutes [95% CI: 54, 85] vs 63 minutes [95% CI: 55, 71]) were on average reduced after implementation, future efforts are necessary to streamline the workflow all along the workflow chain. It is crucial to define a clear framework and recognize limitations as AI tools are only as reliable as the environment in which they are deployed. Keywords: CT, CNS, Stroke, Diagnosis, Classification, Application Domain © RSNA, 2022.

Direct to angiography suite approaches for the triage of suspected acute stroke patients: a systematic review and meta-analysis.

BACKGROUND: Increasing evidence suggests improved time metrics leading to better clinical outcomes when stroke patients with suspected large vessel occlusion (LVO) are transferred directly to the angiography suite (DTAS) compared with cross-sectional imaging followed by transfer to the angiography suite. We performed a systematic review and meta-analysis on the efficacy and safety of DTAS approaches. METHODS: We searched Embase, Medline, Scopus, and clinicaltrials.gov for studies comparing outcomes of DTAS and conventional triage. Eligible studies were assessed for risk of bias. We performed a random-effects meta-analysis on the differences of median door-to-groin and door-to-reperfusion times between intervention and control group. Secondary outcomes included good outcome at 90 days (modified Rankin Scale ⩽ 2) rate of symptomatic intracranial hemorrhage (sICH) and mortality within 90 days. RESULTS: Eight studies (one randomized, one cluster-randomized trial and six observational studies) with 1938 patients were included. Door-to-groin and door-to-reperfusion times in the intervention group were on median 29.0 min [95% confidence interval (CI): 14.3-43.6; p < 0.001] and 32.1 min (95% CI: 15.1-49.1; p < 0.001) shorter compared with controls. Prespecified subgroup analyses for transfer (n = 1753) and mothership patients (n = 185) showed similar reductions of the door-to-groin and door-to-reperfusion times in response to the intervention. The odds of good outcome did not differ significantly between both groups but were numerically higher in the intervention group (odds ratio: 1.38, 95% CI: 0.97-1.95; p = 0.07). There was no significant difference for mortality and sICH between the groups. CONCLUSION: DTAS approaches for the triage of suspected LVO patients led to a significant reduction in door-to-groin and door-to-reperfusion times but an effect on functional outcome was not detected. The subgroup analysis showed similar results for transfer and mothership patients.Registration: This study was registered in PROSPERO (CRD42020213621).

Hemodynamic Characteristics and Clinical Outcome for Intracranial Aneurysms Treated with the Derivo Embolization Device, a Novel Second-Generation Flow Diverter.

BACKGROUND: We investigated the relationship between hemodynamic characteristics and clinical outcomes for aneurysms treated by the Derivo embolization device, a novel second-generation flow-diverter stent, using computational fluid dynamics (CFD). METHODS: Data were retrospectively obtained from 2 centers between 2017 and 2019. During the period, 23 patients were treated for 23 aneurysms with the Derivo embolization device. In 17 patients we were able to conduct CFD analysis as 6 were excluded due to precoiling, unsuitable arterial geometry, and complex geometric form. Aneurysm occlusion was rated with the O'Kelly-Marotta grading scale on digital subtraction angiography 6 months after stent placement in all patients. Hemodynamic and morphologic parameters were statistically compared between 2 groups: with full occlusion and with a remnant. RESULTS: Full occlusion was observed in 17 of 23 (73.9%) patients. In the group suitable for CFD analysis, we observed 13 fully occluded aneurysms and 4 with any remnant (specifically 1 O'Kelly-Marotta C, 1 B, and 2 A). The energy loss per volume, which indicates the energy loss through the aneurysm, was significantly larger in prestenting and post stenting (P < 0.05) in the complete occlusion cases. In addition, the inflow concentration index and inflow area ratio of the remnant cases were significantly larger and lower, respectively (P < 0.05). CONCLUSIONS: Our CFD results indicate that the energy loss involved with the blood flow passing through an aneurysm and concentrated inflow into an aneurysm were the most important factors to determine whether an aneurysm will become a complete occlusion or remnant case.

Distribution of Diagnoses and Clinical and Imaging Characteristics in 1,322 Consecutive Suspected Stroke Patients.

Background: Endovascular thrombectomy (EVT) has become the standard of care for large-vessel occlusion strokes, but several barriers for implementing an optimal organization of stroke management remain. Major issues include the lack of reliable data on the percentage of stroke patients potentially eligible for EVT especially in times of expanding indications for EVT. Our aim was therefore to study the frequencies of possible EVT-eligible patients such as patients with medium-vessel occlusions, patients with low Alberta Stroke Program Early Computed Tomography Scores (ASPECTS), patients presenting in an extended time window after onset of symptoms, and patients with mild symptoms at presentation (National Institutes of Health Stroke Scale, NIHSS ≤ 5). We also give detailed imaging and clinical information about the patients presenting with intracranial hemorrhage and other ischemic stroke mimics stratified by symptoms at presentation. Methods: Cohort study of all consecutive patients with suspected acute stroke presenting to a tertiary care center in Germany between September 1, 2016, and August 31, 2017. Baseline and follow-up clinical and imaging characteristics were collected from patients' medical charts. Results: Of 1,322 patients with a suspected acute stroke, 592 (44.8%) had ischemic strokes, 221 (16.7%) had hemorrhagic strokes, 190 (10.9%) had transient ischemic attacks (TIAs), and 319 (24.1%) were classified as stroke mimics. Stroke severity was mild (NIHSS ≤ 5) in 866 (65.5%) patients; 15.7% of the patients with an occlusion of the anterior circulation had an ASPECTS ≤ 5, 17.4% of the patients with an ischemic stroke had distal vessel occlusions, and 49% of the patients presented later than 6 h after onset of symptoms. Conclusion: Our results help to plan resources in thrombectomy-capable centers in times of expanding indications for EVT where resources will have to be adjusted to patients with low-NIHSS, low-ASPECTS, and distal occlusions, and patients presenting in the extended time window, which may altogether account for an additional 20% of all ischemic stroke patients.

CT Hypoperfusion-Hypodensity Mismatch to Identify Patients With Acute Ischemic Stroke Within 4.5 Hours of Symptom Onset.

BACKGROUND AND OBJECTIVES: To test the hypothesis that CT hypoperfusion-hypodensity mismatch identifies patients with ischemic stroke within 4.5 hours of symptom onset. METHODS: We therefore performed the Retrospective Multicenter Hypoperfusion-Hypodensity Mismatch for The identification of Patients With Stroke Within 4.5 Hours study of patients with acute ischemic stroke and known time of symptom onset. The predictive values of hypoperfusion-hypodensity mismatch for the identification of patients with symptom onset within 4.5 hours were the main outcome measure. RESULTS: Of 666 patients, 548 (82.3%) had multimodal CT within 4.5 hours and 118 (17.7%) beyond 4.5 hours. Hypoperfusion-hypodensity mismatch was visible in 516 (94.2%) patients with symptom onset within and in 30 (25.4%) patients beyond 4.5 hours. CT hypoperfusion-hypodensity mismatch identified patients within 4.5 hours of stroke onset with 94.2% (95% confidence interval [CI] 91.9%-95.8%) sensitivity, 74.6% (95% CI 66.0%-81.6%) specificity, 94.5% (95% CI 92.3%-96.1%) positive predictive value, and 73.3% (95% CI 64.8%-80.4%) negative predictive value. Interobserver agreement for hypoperfusion-hypodensity mismatch was substantial (κ = 0.61, 95% CI 0.53-0.69). DISCUSSION: Patients with acute ischemic stroke with absence of a hypodensity on native CT (NCCT) within the hypoperfused core lesion on perfusion CT (hypoperfusion-hypodensity mismatch) are likely to be within the time window of thrombolysis. Applying this method may guide the decision to use thrombolysis in patients with unknown time of stroke onset. TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov Identifier: NCT04277728. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that CT hypoperfusion-hypodensity mismatch identifies patients with stroke within 4.5 hours of onset.

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.