Effect of intra-arterial nimodipine on iatrogenic vasospasms during endovascular stroke treatment - angiographic resolution and infarct growth in follow-up imaging.

PURPOSE: The treatment of vasospasms during endovascular stroke treatment (EST) with intra-arterial nimodipine (NM) is routinely performed. However, the efficacy of resolving iatrogenic vasospasms during the angiographic intervention and the infarct development in follow-up imaging after EST has not been studied yet. METHODS: Retrospective single-center analysis of patients receiving EST for anterior circulation vessel occlusion between 01/2015 and 12/2021. The primary endpoint was ASPECTS in follow-up imaging. Secondary endpoints were the clinical outcome (combined endpoint NIHSS 24 h after EST and difference between modified Rankin Scale (mRS) before stroke and at discharge (delta mRS)) and intracranial hemorrhage (ICH) in follow-up imaging. Patients with vasospasms receiving NM (NM+) or not (NM-) were compared in univariate analysis. RESULTS: Vasospasms occurred in 79/1283 patients (6.2%), who consecutively received intra-arterial NM during EST. The targeted vasospasm angiographically resolved in 84% (66/79) under NM therapy. ASPECTS was lower in follow-up imaging after vasospasms and NM-treatment (NM - 7 (6-9), NM + 6 (4.5-8), p = 0.013) and the clinical outcome was worse (NIHSS 24 h after EST was higher in patients treated with NM (median, IQR; NM+: 14, 5-21 vs. NM-: 9, 3-18; p = 0.004), delta-mRS was higher in the NM + group (median, IQR; NM+: 3, 1-4 vs. NM-: 2, 1-2; p = 0.011)). Any ICH (NM+: 27/79, 34.2% vs. NM-: 356/1204, 29.6%; p = 0.386) and symptomatic ICH (NM+: 2/79, 2.5% vs. NM-: 21/1204, 1.7%; p = 0.609) was equally distributed between groups. CONCLUSION: Intra-arterial nimodipine during EST resolves iatrogenic vasospasms efficiently during EST without increasing intracranial hemorrhage rates. However, patients with vasospasms and NM treatment show higher infarct growth resulting in lower ASPECTS in follow-up imaging.

[Comparison of acute stroke care pathways-A qualitative multicenter study in three referring hospitals of a stroke network]. / Vergleich von Behandlungspfaden beim akuten Schlaganfall ­ eine qualitative multizentrische Studie in drei zuweisenden Kliniken eines Schlaganfallnetzwerkes.

BACKGROUND: In stroke networks, hospitals that do not provide thrombectomy (referring hospitals) refer patients to specialized hospitals (receiving hospitals) for this specific intervention. In order to improve the access and management of thrombectomy, the focus of research needs to be not only on the receiving hospitals but also on the prior stroke care pathways in referring hospitals. OBJECTIVE: The purpose of this study was to investigate the stroke care pathways in different referring hospitals as well as the advantages and disadvantages associated with these pathways. METHODS: A qualitative multicenter study was carried out in three referring hospitals of a stroke network. Stroke care was assessed and analyzed by using non-participant observations and 15 semi-structured interviews with employees in various health professions. RESULTS: The following aspects were reported as advantageous within the stroke care pathways: (1) a structured and personal prenotification of the patient by the emergency medical service (EMS) members; (2) a more efficiently organized teleneurology workflow; (3) the provision of the secondary referral to thrombectomy by the same EMS members of the primary referral and (4) the integration of external neurologists into in-house structures. CONCLUSION: The study provides insights into different stroke care pathways of three different referring hospitals of a stroke network. The results can be used to derive potentials for improvement of other referring hospitals; however, this study is too small to provide reliable information about their potential effectiveness. Future studies should investigate whether implementation of these recommendations actually leads to improvements and under which conditions they are successful. To ensure patient-centeredness, the perspectives of patients and relatives should also be included.

A Trial Patch to Sustainable Development: Perspectives from Extracurricular Activities of Elementary Schools in Turkey.

Sustainable development (SD) and science education have become interwoven categorical issues under the name of science education for sustainable development (SESD). Education can play a crucial role in merging the dimensions of SD as ecology, economy, and energy, along with society in a united holistic goal. Furthermore, it can provide the necessary motivation and self-fulfillment for individuals and communities. Extracurricular activities should also be implemented along with formal ones in courses that are related to socio-scientific issues like SD. In line with this perspective, this study mainly aims to find new means of developing an extracurricular module program based on the principles of SD, in order to address the defects, deficiencies, and needs in science education around the world. The module program was constructed through use of the concepts of energy transformations, biodiversity, and narrating socio-scientific problems that would foster positive student decision-making on SD issues. The study also aims to examine whether the SESD module program would have a significant effect on the academic success and opinions regarding SD of primary school students in science lessons. The study sample comprised 92 Turkish fifth-grade students. Mixed methods using both qualitative and quantitative approaches were used. Data analysis revealed that the SESD module program significantly affected fifth-grade students in terms of their knowledge and opinions for increased willingness to take action and responsibility.

Reperfusion Without Functional Independence in Late Presentation of Stroke With Large Vessel Occlusion.

BACKGROUND: Reperfusion without functional independence (RFI) is an undesired outcome following thrombectomy in acute ischemic stroke. The primary objective was to evaluate, in patients presenting with proximal anterior circulation occlusion stroke in the extended time window, whether selection with computed tomography (CT) perfusion or magnetic resonance imaging is associated with RFI, mortality, or symptomatic intracranial hemorrhage (sICH) compared with noncontrast CT selected patients. METHODS: The CLEAR study (CT for Late Endovascular Reperfusion) was a multicenter, retrospective cohort study of stroke patients undergoing thrombectomy in the extended time window. Inclusion criteria for this analysis were baseline National Institutes of Health Stroke Scale score ≥6, internal carotid artery, M1 or M2 segment occlusion, prestroke modified Rankin Scale score of 0 to 2, time-last-seen-well to treatment 6 to 24 hours, and successful reperfusion (modified Thrombolysis in Cerebral Infarction 2c-3). RESULTS: Of 2304 patients in the CLEAR study, 715 patients met inclusion criteria. Of these, 364 patients (50.9%) showed RFI (ie, mRS score of 3-6 at 90 days despite successful reperfusion), 37 patients (5.2%) suffered sICH, and 127 patients (17.8%) died within 90 days. Neither imaging selection modality for thrombectomy candidacy (noncontrast CT versus CT perfusion versus magnetic resonance imaging) was associated with RFI, sICH, or mortality. Older age, higher baseline National Institutes of Health Stroke Scale, higher prestroke disability, transfer to a comprehensive stroke center, and a longer interval to puncture were associated with RFI. The presence of M2 occlusion and higher baseline Alberta Stroke Program Early CT Score were inversely associated with RFI. Hypertension was associated with sICH. CONCLUSIONS: RFI is a frequent phenomenon in the extended time window. Neither magnetic resonance imaging nor CT perfusion selection for mechanical thrombectomy was associated with RFI, sICH, and mortality compared to noncontrast CT selection alone. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04096248.

"But it's a nice compromise" - Qualitative multi-centre study of barriers and facilitators to acute telestroke cooperation in a regional stroke network.

BACKGROUND: Telemedical services can be used to complement on-site services when demand for specialists exceeds supply or when specialists are not evenly distributed across health systems. Using stroke as an example, this study aimed to explore how patients and staff experience telestroke cooperation in a stroke network in Germany. METHODS: We conducted a qualitative multi-method and multi-centre study combining 32 non-participant observations at one hub and four spoke hospitals with 26 semi-structured interviews with hub and spoke staff as well as stroke patients and relatives. Observation protocols and interview transcripts were analysed to identify barriers and facilitators to telestroke cooperation from the perspectives of staff, patients and relatives. RESULTS: In terms of barriers to telestroke cooperation, we found technological problems, providing the treatment for one patient from two sites, competing priorities between telestroke and in-house duties in the spoke hospitals, as well as difficulties in participating in the teleneurological examination via a videoconferencing system for older and disabled patients. In terms of facilitators, we found an overall very positive perception of telestroke provision by patients, good professional relationships within the network, and sharing of neurological expertise to be experienced as helpful for telestroke cooperation. CONCLUSIONS: We recommend better integration of telemedical services into the care pathway, fostering relationships within the network, improved technological support and resources, and more emphasis within networks, in public awareness efforts as well as in academia on the evaluation of telemedical services from the perspectives of patients and relatives, especially older patients and patients with disabilities.

Role of diabetes in collateral status assessed in CT perfusion-derived dynamic CTA in anterior circulation stroke.

PURPOSE: Diabetes is associated with vascular dysfunction potentially impairing collateral recruitment in acute ischemic stroke. This retrospective study aimed at analyzing the impact of diabetes on collateralization assessed on dynamic CTA. METHODS: Collaterals were retrospectively assessed on CT perfusion-derived dynamic CTA according to the mCTA score by Menon in a cohort of patients with an acute occlusion of the M1 segment or carotid T. The extent of collateral circulation was related to the history of diabetes and to admission blood glucose and HbA1c levels. RESULTS: Two hundred thirty-nine patients were included. The mCTA collateral score was similar in patients with diabetes (median 3, interquartile range 3-4) and without diabetes (median 4, interquartile range 3-4) (P = 0.823). Diabetes was similarly frequent in patients with good (18.8%), intermediate (16.1%), and poor collaterals (16.0%) (P = 0.355). HbA1c was non-significantly higher in patients with poor collaterals (6.3 ± 1.5) compared to patients with intermediate (6.0 ± 0.9) and good collaterals (5.8 ± 0.9) (P = 0.061). Blood glucose levels were significantly higher in patients with poor compared to good collaterals (mean 141.6 vs. 121.8 mg/dl, P = 0.045). However, there was no significant difference between good and intermediate collaterals (mean 121.8 vs. 129.5 mg/dl, P = 0.161) as well as between intermediate and poor collaterals (129.5 vs. 141.6 mg/dl, P = 0.161). CONCLUSION: There was no statistically significant difference among patients with good, intermediate, and poor collaterals regarding the presence of diabetes or HbA1c level on admission. However, stroke patients with poor collaterals tend to have higher blood glucose and HbA1c levels.

Deep Learning-Based Automated Thrombolysis in Cerebral Infarction Scoring: A Timely Proof-of-Principle Study.

Background and Purpose: Mechanical thrombectomy is an established procedure for treatment of acute ischemic stroke. Mechanical thrombectomy success is commonly assessed by the Thrombolysis in Cerebral Infarction (TICI) score, assigned by visual inspection of X-ray digital subtraction angiography data. However, expert-based TICI scoring is highly observer-dependent. This represents a major obstacle for mechanical thrombectomy outcome comparison in, for instance, multicentric clinical studies. Focusing on occlusions of the M1 segment of the middle cerebral artery, the present study aimed to develop a deep learning (DL) solution to automated and, therefore, objective TICI scoring, to evaluate the agreement of DL- and expert-based scoring, and to compare corresponding numbers to published scoring variability of clinical experts. Methods: The study comprises 2 independent datasets. For DL system training and initial evaluation, an in-house dataset of 491 digital subtraction angiography series and modified TICI scores of 236 patients with M1 occlusions was collected. To test the model generalization capability, an independent external dataset with 95 digital subtraction angiography series was analyzed. Characteristics of the DL system were modeling TICI scoring as ordinal regression, explicit consideration of the temporal image information, integration of physiological knowledge, and modeling of inherent TICI scoring uncertainties. Results: For the in-house dataset, the DL system yields Cohen's kappa, overall accuracy, and specific agreement values of 0.61, 71%, and 63% to 84%, respectively, compared with the gold standard: the expert rating. Values slightly drop to 0.52/64%/43% to 87% when the model is, without changes, applied to the external dataset. After model updating, they increase to 0.65/74%/60% to 90%. Literature Cohen's kappa values for expert-based TICI scoring agreement are in the order of 0.6. Conclusions: The agreement of DL- and expert-based modified TICI scores in the range of published interobserver variability of clinical experts highlights the potential of the proposed DL solution to automated TICI scoring.

Clinical Outcome After Endovascular Thrombectomy in 3 Triage Concepts: A Prospective, Observational Study (NEUROSQUAD).

BACKGROUND AND PURPOSE: NEUROSQUAD (Stroke Treatment: Quality and Efficacy in Different Referral Systems) is a prospective, observational, bicenter study comparing 3 triage pathways in endovascular stroke treatment: mothership, drip and ship (DS), and transferring a neurointerventionalist to a remote hospital for thrombectomy (drive the doctor [DD]). METHODS: Patients with anterior circulation stroke and premorbid modified Rankin Scale (mRS) score 0-3 who underwent thrombectomy within 24 hours after stroke onset were included. Primary outcome measure was good clinical outcome defined as 90-day mRS score 0-2 or clinical recovery to the status before stroke onset (ie, equal premorbid mRS and 90-day mRS). Secondary outcome measures were successful reperfusion, National Institutes of Health Stroke Scale at discharge, and mRS shift. RESULTS: In total, 360 patients were included in this study, of whom 111 patients (30.8%) were in the mothership group, 204 patients (56.7%) were in the DS group, and 45 patients (12.5%) were in the DD group. Good clinical outcome was achieved similarly in all three groups (mothership, 45.9%; DS, 43.1%; DD, 40.0%; P=0.778). Likewise, frequency of successful reperfusion was similar in all three groups (mothership, 86.5%; DS, 85.3%; DD, 82.2%; P=0.714). There was no significant difference among the groups regarding the National Institutes of Health Stroke Scale at discharge (P=0.115) and mRS shift (P=0.342). In the multivariate analysis, triage concept was not an independent predictor of good outcome (unadjusted odds ratio, 0.89 [CI, 0.64-1.23]; P=0.479). CONCLUSIONS: Our data suggest that clinical outcome after thrombectomy is similar in mothership, DS, and DD. Hence, DD can be a valuable triage option in acute stroke treatment.

Impact of bridging thrombolysis on clinical outcome in stroke patients undergoing endovascular thrombectomy: a retrospective analysis of a regional stroke registry.

PURPOSE: It is unclear whether stroke patients undergoing endovascular thrombectomy (EVT) should receive bridging intravenous thrombolysis (IVT), if eligible. This study aims at analyzing the impact of bridging IVT on short-term clinical outcome. METHODS: In a prospective regional stroke registry, all stroke patients with premorbid modified Rankin Scale (mRS) score of 0-2 who were admitted within 4.5 h after onset and treated with EVT were analyzed retrospectively. Patients receiving "IVT prior to EVT" (IVEVT) were compared to those undergoing "EVT only" regarding the ratio of good outcome, discharge mRS, mRS shift, hospital mortality, and occurrence of symptomatic intracranial hemorrhage. RESULTS: In total, 2022 patients were included, 816 patients (40.4%) achieved good clinical outcome; 1293 patients (63.9%) received bridging IVT. There was no significant difference between both groups regarding the ratio of good outcome (IVEVT 41.4% vs. EVT 38.5%, P = 0.231), discharge mRS (median, IVEVT 3 vs. EVT 3, P = 0.178), mRS shift (median, IVEVT 3 vs. EVT 3, P = 0.960), and hospital mortality (IVEVT 19.3% vs. EVT 19.5%, P = 0.984). Bridging IVT was not a predictor of outcome (adjusted OR 1.00, 95% CI 0.79-1.26, P = 0.979). However, it was an independent predictor of symptomatic intracranial hemorrhage (adjusted OR 1.79, 95% CI 1.21-2.72, P = 0.005). CONCLUSIONS: The results of the present study suggest that bridging IVT does not seem to improve short-term clinical outcome of patients undergoing EVT. Nonetheless, there might be a subgroup of patients that benefits from IVT. This needs to be addressed in randomized controlled trials.

Time Metrics to Endovascular Thrombectomy in 3 Triage Concepts: A Prospective, Observational Study (NEUROSQUAD).

Background and Purpose- NEUROSQUAD (Stroke Treatment: Quality and Efficacy in Different Referral Systems) is a prospective, observational, bi-center study comparing 3 triage pathways in endovascular stroke treatment: mothership (MS), drip and ship (DS) and transferring a neurointerventionalist to a remote hospital for thrombectomy (drive the doctor [DD]). Methods- Between February and October 2018, all stroke patients undergoing thrombectomy at 2 university hospitals and 2 associated remote hospitals were included. Primary outcome measures were time from onset to groin puncture and time from imaging to groin puncture. Secondary outcome measures were time from onset to imaging and time from onset to thrombolysis. Results- In total, 440 patients were included (mothership 32.3%, DS 55.9%, DD 11.8%). Median time from onset to groin puncture (168 minutes) and time from imaging to groin puncture (51 minutes) were the shortest in the mothership group. Time from onset to groin puncture (DD median 225 versus DS median 300 minutes; P=0.001) and time from imaging to groin puncture (DD median 118 versus DS median 172 minutes; P<0.001) were shorter in the DD group compared with DS. Time from onset to imaging was similar among mothership, DS, and DD (P=0.363). In patients receiving thrombolysis, time from onset to needle was similar among the groups (P=0.620). Conclusions- The NEUROSQUAD study adds evidence that DD may be a feasible alternative to DS, leading to shorter delay between symptom onset and groin puncture. Both are time-wise inferior compared with mothership, though.

Primary Multivessel Occlusions Treated With Mechanical Thrombectomy: A Multicenter Analysis and Systemic Literature Review.

BACKGROUND AND PURPOSE: Acute ischemic stroke caused by primary multivessel occlusions (pMVO) is a rare but devastating disease. Whether multi-target mechanical thrombectomy for pMVO is beneficial remains unknown. METHODS: Multicenter retrospective review of patients treated with multi-target mechanical thrombectomy. The following pMVO sites were included: basilar artery, internal carotid artery, and middle cerebral artery (M1 and M2). Baseline characteristics were reported together with interventional technique, technical efficacy, and safety parameters. Clinical outcomes were evaluated applying the National Institutes of Health Stroke Scale and modified Rankin Scale. A systematic literature review was performed to summarize previous reports on pMVO mechanical thrombectomy. RESULTS: Of 6081 patients screened, 21 patients met the inclusion criteria (0.35% [95% CI, 0.23%-0.53%]). In 70% (14/20) a cardioembolic cause was reported. A successful reperfusion of Thrombolysis in Cerebral Infarction scale score ≥2b was achieved in 95.2% (20/21) for the first and 76.1% (16/21) for the second target vessel. In those who survived the acute hospital stay (n=10/21), median admission National Institutes of Health Stroke Scale improved from 21 (interquartile range, 13-27) to 8 (interquartile range, 2-20) at discharge (P=0.006). Mortality was 60% (12/20) at 90 days and only 20% (4/20) of patients reached modified Rankin Scale score ≤2. Acceptable outcomes were almost exclusively observed in pMVO patients presenting with at least one M2 occlusion. CONCLUSIONS: Multi-target mechanical thrombectomy for pMVOs is rarely performed; however, the procedure appears to be feasible and safe with high reperfusion rates for both occlusion sites. More than half of all treated patients deceased early and favorable outcomes may only be expected for pMVO patients including at least one M2 occlusion.

Radiation exposure per thrombectomy attempt in modern endovascular stroke treatment in the anterior circulation.

OBJECTIVE: To quantify radiation exposure (RE) of endovascular stroke treatment (EST) in the anterior circulation per thrombectomy attempt and determine causes for interventions associated with high RE. METHODS: A retrospective single-center study of an institutional review board-approved stroke database of patients receiving EST for large vessel occlusions in the anterior circulation between January 2013 and April 2018 to evaluate reference levels (RL) per thrombectomy attempt. ESTs with RE above the RL were analyzed to determine causes for high RE. RESULTS: Overall, n = 544 patients (occlusion location, M1 and M2 segments of the middle cerebral artery 53.5% and 27.2%, carotid artery 17.6%; successful recanalization rate 85.7%) were analyzed. In the overall population, DAP (in Gy cm2, median (IQR)) was 113.7 (68.9-181.7) with a median fluoroscopy time of 31 min (IQR, 17-53) and a median of 2 (IQR, 1-4) thrombectomy attempts. RE increased significantly with every thrombectomy attempt (DAP1, 68.7 (51.2-106.8); DAP2, 106.4 (84.8-115.6); p value1vs2, < 0.001; DAP3, 130.2 (89.1-183.6); p value2vs3, 0.044; DAP4, 169.9 (128.4-224.1); p value3vs4, 0.001; and DAP5, 227.6 (146.3-294.6); p value4vs5, 0.019). Procedures exceeding the 90th percentile of the attempt-dependent radiation exposure level were associated with procedural complications (n = 17/52, 29.8%) or a difficult vascular access (n = 8/52, 14%). CONCLUSIONS: Radiation exposure in endovascular stroke treatment is depending on the number of thrombectomy attempts. Radiation exposure doubles when three attempts and triples when five attempts are necessary compared with single-maneuver interventions. Procedural complications and difficult vascular access were associated with a high radiation exposure in this collective. KEY POINTS: • Radiation exposure of endovascular stroke treatment (EST) is dependent on the number of thrombectomy attempts. • Reference levels as means for quality control in hospitals performing endovascular stroke treatment should be defined by the number of thrombectomy attempts-we suggest 107 Gy cm2, 156 Gy cm2, 184 Gy cm2, 244 Gy cm2, and 295 Gy cm2 for 1 to 5 maneuvers, respectively, for EST of the anterior circulation • Cases with high rates of radiation exposure are associated with periprocedural complications and difficult anatomical access as a probable cause for a high radiation exposure.

Distal arterial occlusions in patients with mild strokes - is endovascular therapy superior to thrombolysis alone?

BACKGROUND AND PURPOSE: Safety and efficacy of endovascular thrombectomy (EVT) in patients with mild stroke syndromes is unclear, especially in distal vessel occlusions. METHODS: We analysed in our stroke database (HeiReKa) between 2002 and April 2019 safety and efficacy of EVT compared to intravenous thrombolysis (IVT) in patients with occlusions distal to the M1 segment of the middle cerebral artery and the top of the basilar artery who presented with a National Institute of Health Stroke Scale (NIHSS) below 6. Excellent (good) outcome was defined as modified rankin scale (mRS) 0-1 (0-2) or return to baseline mRS (good) after 3 months. Safety endpoints were mortality after 3 months and intracranial hemorrhage according to the Heidelberg Bleeding Classification (HBC). RESULTS: Of 4167 patients 94 met the inclusion criteria. Sixty-four patients were allocated to the IVT group and 30 to the EVT group of which 15 also received IVT; three patients (4.6%) in the IVT group received rescue EVT. Baseline characteristics did not differ but more M2 occlusions were found in the EVT group (93.3% vs. 64.1%, p = 0.02). Intracranial bleeding occurred more often in EVT patients (HBC class 2: 13.3% vs. 1.6%, p = 0.01). Excellent and good outcome were not significantly different (75% vs. 70%, p = 0.65 and 87.5% vs. 73.3%, p = 0.14). Mortality was significantly lower in IVT patients (1.6% vs. 13.3%, p = 0.04). CONCLUSION: Rates of excellent and good outcome after IVT or EVT were almost similar, but safety parameters were increased after EVT. EVT may be considered in selected patients after careful risk/benefit analysis.

Carotid Artery Stenosis Contralateral to Acute Tandem Occlusion: An Independent Predictor of Poor Clinical Outcome after Mechanical Thrombectomy with Concomitant Carotid Artery Stenting.

BACKGROUND AND PURPOSE: Cerebral ischemic strokes due to extra-/intracranial tandem occlusions (TO) of the anterior circulation are responsible for causing mechanical thrombectomy (MT). The impact of concomitant contralateral carotid stenosis (CCS) upon outcome remains unclear in this stroke subtype. METHODS: Retrospective analysis of prospectively collected data of 4 international stroke centers between 2011 and 2017. One hundred ninety-seven consecutive patients with anterior TO were treated with MT and acute carotid artery stenting (CAS). Clinical (including demographics and National Institutes of Health Stroke Scale [NIHSS]), imaging (including angiographic evaluation of CCS) and procedural data were evaluated. Favorable clinical outcome was defined as modified Rankin Scale (mRS) ≤2 at 90 days. RESULTS: In 186 out of 197 TO patients preinterventional CT angiography was available for analysis, thereof 49 patients (26%) presented with CCS. Median admission NIHSS and procedural timings did not differ between groups. Reperfusion was successful in 38 out of 49 patients (78%) vs. 113 out of 148 patients (76%) without CCS. In stark contrast, rate of favorable outcome at 90 days differed significantly between groups (22 vs. 44%; p < 0.05). The presence of CCS in TO was associated with an unfavorable clinical outcome independent of age and NIHSS in multivariate logistic regression (p < 0.05). Final infarct volume was significantly larger in CCS patients (100 ± 127 vs. 63 ± 77 cm3; p < 0.05). Neither all-cause mortality rates (25 vs. 17%) nor frequency of peri-interventional symptomatic intracranial hemorrhage differed between groups (7 vs. 6%). CONCLUSION: For patients with anterior TO undergoing MT with concomitant CAS the presence of CCS >50% is an independent predictor of poor clinical outcome. This most likely cause is due to poorer collateral flow to the affected tissue.

A novel method to assess pial collateralization from stroke perfusion MRI: subdividing Tmax into anatomical compartments.

OBJECTIVES: To develop and validate a quantitative and observer-independent method to evaluate pial collateral circulation by DSC-perfusion MRI and test whether this novel method delivers diagnostic information which is redundant to or independent from conventional penumbra imaging by the mismatch approach. METHODS: We retrospectively identified 47 patients with M1 occlusion who underwent MR diffusion/perfusion imaging and mechanical thrombectomy at our facility. By automated registration and segmentation, Tmax delays were attributed specifically to the pial, cortical and parenchymal compartments. The resulting pial volumes at delay were defined as the pial Tmax map-assessed collateral score (TMACS) and correlated with gold standard digital subtraction angiography (DSA). Mismatch ratio was assessed by conventional penumbra defining MRI criteria. RESULTS: Strong correlation was found between TMACS and angiographically assessed collateral score (Pearson ρ = -0.74, p < 0.001). In multiple logistic regression, both good collaterals according to TMACS [OR 4.3 (1.1-19, p = 0.04)] and mismatch ratio ≥ 3.5 [OR 12.3 (1.88-249, p = 0.03)] were independent predictors of favourable clinical outcome. CONCLUSIONS: Perfusion delay in the pial compartment, as evaluated by TMACS, closely reflects the extent of pial collaterals in gold-standard DSA. TMACS and mismatch ratio were found to be complementary predictors of a favourable clinical outcome, each adding independent predictive information. KEY POINTS: • MRI-DSC perfusion delay specific in the pial compartment reflects leptomeningeal collateralization. • A novel quantitative- and observer-independent marker of collateral status (TMACS) is introduced. • Quantification of collateral status leads to an independent predictor of neurological outcome.

Association of Carotid Artery Disease with Collateralization and Infarct Growth in Patients with Acute Middle Cerebral Artery Occlusion.

BACKGROUND AND PURPOSE: Collaterals are important in large vessel occlusions (LVO), but the role of carotid artery disease (CAD) in this context remains unclear. This study aimed to investigate the impact of CAD on intracranial collateralization and infarct growth after thrombectomy in LVO. MATERIALS AND METHODS: All patients who underwent thrombectomy due to M1 segment occlusion from 01/2015 to 12/2021 were retrospectively included. Internal carotid artery stenosis according to NASCET was assessed on the affected and nonaffected sides. Collaterals were assessed according to the Tan score. Infarct growth was quantified by comparing ASPECTS on follow-up imaging with baseline ASPECTS. RESULTS: In total, 709 patients were included, 118 (16.6%) of whom presented with CAD (defined as severe stenosis ≥70% or occlusion ipsilaterally), with 42 cases (5.9%) being contralateral. Good collateralization (Tan 3) was present in 56.5% of the patients with ipsilateral CAD and 69.1% of the patients with contralateral CAD. The ipsilateral stenosis grade was an independent predictor of good collateral supply (adjusted OR: 1.01; NASCET point, 95% CI: 1.00-1.01; P = .009), whereas the contralateral stenosis grade was not (P = .34). Patients with ipsilateral stenosis of ≥70% showed less infarct growth (median ASPECTS decay: 1; IQR: 0-2) compared with patients with 0%-69% stenosis (median: 2; IQR: 1-3) (P = .005). However, baseline ASPECTS was significantly lower in patients with stenosis of 70%-100% (P < .001). The results of a multivariate analysis revealed that increasing ipsilateral stenosis grade (adjusted OR: 1.0; 95% CI: 0.99-1.00; P = .004) and good collateralization (adjusted OR: 0.5; 95% CI: 0.4-0.62; P < .001) were associated with less infarct growth. CONCLUSIONS: CAD of the ipsilateral ICA is an independent predictor of good collateral supply. Patients with CAD tend to have larger baseline infarct size but less infarct growth.

Dose-response relationship of locally applied nimodipine in an ex vivo model of cerebral vasospasm.

INTRODUCTION: Cerebral vasospasm is a severe complication of subarachnoid hemorrhage (SAH). The calcium channel inhibitor nimodipine has been used for treatment of cerebral vasospasm. No evidence-based recommendations for local nimodipine administration at the site of vasospasm exist. The purpose of this study was to quantify nimodipine's local vasodilatory effect in an ex vivo model of SAH-induced vasospasm. METHODS: SAH-induced vasospasm was modeled by contracting isolated segments of rat superior cerebellar arteries with a combination of serotonin and a synthetic analog of prostaglandin A(2). A pressure myograph system was used to determine vessel reactivity of spastic as well as non-spastic arteries. RESULTS: Compared to the initial vessel diameter, a combination of serotonin and prostaglandin induced considerable vasospasm (55 ± 2.5 % contraction; n = 12; p < 0.001). Locally applied nimodipine dilated the arteries in a concentration-dependent manner starting at concentrations as low as 1 nM (n = 12; p < 0.05). Concentrations higher than 100 nM did not relevantly increase the vasodilatory effect. Nimodipine's vasodilatory effect was smaller in spastic than in non-spastic vessels (n = 12; p < 0.05), which we assume to be due to structural changes in the vessel wall. CONCLUSION: The described ex vivo model allows to investigate the dose-dependent efficacy of spasmolytic drugs prior to in vivo experiments. Low concentrations of locally applied nimodipine have a strong vasodilatory effect, which is of relevance when considering the local application of nimodipine in cerebral vasospasm.

Deep Learning-based Assessment of Internal Carotid Artery Anatomy to Predict Difficult Intracranial Access in Endovascular Recanalization of Acute Ischemic Stroke.

BACKGROUND: Endovascular thrombectomy (EVT) duration is an important predictor for neurological outcome. Recently it was shown that an angle of ≤ 90° of the internal carotid artery (ICA) is predictive for longer EVT duration. As manual angle measurement is not trivial and time-consuming, deep learning (DL) could help identifying difficult EVT cases in advance. METHODS: We included 379 CT angiographies (CTA) of patients who underwent EVT between January 2016 and December 2020. Manual segmentation of 121 CTAs was performed for the aortic arch, common carotid artery (CCA) and ICA. These were used to train a nnUNet. The remaining 258 CTAs were segmented using the trained nnUNet with manual verification afterwards. Angles of left and right ICAs were measured resulting in two classes: acute angle ≤ 90° and > 90°. The segmentations together with angle measurements were used to train a convolutional neural network (CNN) determining the ICA angle. The performance was evaluated using Dice scores. The classification was evaluated using AUC and accuracy. Associations of ICA angle and procedural times was explored using median and Whitney­U test. RESULTS: Median EVT duration for cases with ICA angle > 90° was 48 min and with ≤ 90° was 64 min (p = 0.001). Segmentation evaluation showed Dice scores of 0.94 for the aorta and 0.86 for CCA/ICA, respectively. Evaluation of ICA angle determination resulted in an AUC of 0.92 and accuracy of 0.85. CONCLUSION: The association between ICA angle and EVT duration could be verified and a DL-based method for semi-automatic assessment with the potential for full automation was developed. More anatomical features of interest could be examined in a similar fashion.

Transferring neurointerventionalists saves time compared with interhospital transfer of stroke patients for endovascular thrombectomy: a collaborative pooled analysis of 1001 patients (EVEREST).

BACKGROUND: Interhospital transfer of stroke patients (drip and ship concept) is associated with longer treatment times compared with primary admission to a comprehensive stroke center (mothership concept). In recent years, studies on a novel concept of performing endovascular thrombectomy (EVT) at external hospitals (EXT) by transferring neurointerventionalists, instead of patients, have been published. This collaborative study aimed at answering the question of whether EXT saves time in the workflow of acute stroke treatment across various geographical regions. METHODS: This was a patient level pooled analysis of one prospective observational study and four retrospective cohort studies, the EVEREST collaboration (EndoVascular thrombEctomy at Referring and External STroke centers). Time from initial stroke imaging to EVT (vascular puncture) was compared in mothership, drip and ship, and EXT concepts. RESULTS: In total, 1001 stroke patients from various geographical regions who underwent EVT due to large vessel occlusion were included. These were divided into mothership (n=162, 16.2%), drip and ship (n=458, 45.8%), and EXT (n=381, 38.1%) cohorts. The median time periods from onset to EVT (195 min vs 320 min, p<0.001) and from imaging to EVT (97 min vs 184 min, p<0.001) in EXT were significantly shorter than for drip and ship thrombectomy concept. CONCLUSIONS: This pooled analysis of the EVEREST collaboration adds evidence that performing EVT at external hospitals can save time compared with drip and ship across various geographical regions. We encourage conducting randomized controlled trials comparing both triage concepts.

Aortic Arch Variations and Supra-aortic Arterial Tortuosity in Stroke Patients Undergoing Thrombectomy : Retrospective Analysis of 1705 Cases.

PURPOSE: Unfavorable vascular anatomy can impede thrombectomy in patients with acute ischemic stroke. The aim of this study was to determine the prevalence of aortic arch types, aortic arch branching patterns and supra-aortic arterial tortuosity in stroke patients with large vessel occlusion. METHODS: Computed tomography (CT) and magnetic resonance (MR) images of all stroke patients in an institutional thrombectomy registry were retrospectively reviewed. Aortic arch types and branching patterns of all patients were determined. In patients with anterior circulation stroke, the prevalence of tortuosity (elongation, kinking or coiling) of the supra-aortic arteries of the affected side was additionally assessed. RESULTS: A total of 1705 aortic arches were evaluated. Frequency of aortic arch types I, II and III were 777 (45.6%), 585 (34.3%) and 340 (19.9%), respectively. In 1232 cases (72.3%), there was a normal branching pattern of the aortic arch. The brachiocephalic trunk and the left common carotid artery had a common origin in 258 cases (15.1%). In 209 cases (12.3%), the left common carotid artery arose from the brachiocephalic trunk. Of 1598 analyzed brachiocephalic trunks and/or common carotid arteries, 844 (52.8%) had no vessel tortuosity, 592 (37.0%) had elongation, 155 (9.7%) had kinking, and 7 (0.4%) had coiling. Of 1311 analyzed internal carotid arteries, 471 (35.9%) had no vessel tortuosity, 589 (44.9%) had elongation, 150 (11.4%) had kinking, and 101 (7.7%) had coiling. CONCLUSION: With 20%, type III aortic arches are found in a relevant proportion of stroke patients eligible for mechanical thrombectomy. Nearly half of the stroke patients present with supra-aortic arterial tortuosity, mostly arterial elongation.