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.

Effect of Individualized Versus Standardized Blood Pressure Management During Endovascular Stroke Treatment on Clinical Outcome: A Randomized Clinical Trial.

BACKGROUND: Optimal blood pressure (BP) management during endovascular stroke treatment is not well established. We studied whether an individualized approach for managing BP during endovascular stroke treatment gives a better clinical outcome than an approach with standardized systolic BP targets. METHODS: The INDIVIDUATE study (Individualized Blood Pressure Management During Endovascular Treatment of Acute Ischemic Stroke Under Procedural Sedation) is a randomized clinical trial with a prospective randomized open blinded end point (PROBE) design. Patients were recruited between October 1, 2020 and July 7, 2022 at a single center at a tertiary care university hospital. Patients were eligible, when they were suffering from acute ischemic stroke of the anterior circulation with occlusions of the internal carotid artery and middle cerebral artery and a National Institutes of Health Stroke Scale score of ≥8 receiving endovascular stroke treatment in procedural sedation. The intervention consists of an individualized BP management strategy, where preinterventional baseline systolic BP (SBP) values are used as intraprocedural BP targets. As a control, the standard treatment aims to maintain the intraprocedural SBP between 140 and 180 mm Hg. The main prespecified outcome is the proportion of favorable functional outcomes 90 days after stroke, defined as a modified Rankin Scale score of 0 to 2. RESULTS: Two hundred fifty patients were enrolled and included in the analysis, mean (SD) age was 77 (12) years, 142 (57%) patients were women, and mean (SD) National Institutes of Health Stroke Scale score on admission was 17 (5.2). In all, 123 (49%) patients were treated with individualized and 127 (51%) with standard BP management. Mean (SD) intraprocedural SBP was similar in the individualized versus standard BP management group (157 [19] versus 154 [18] mm Hg; P=0.16). The rate of favorable functional outcome after 3 months was not significantly different between the individualized versus the standard BP management group (25% versus 24%; adjusted odds ratio, 0.81 [95% CI, 0.41-1.61]; P=0.56). CONCLUSIONS: Among patients treated with endovascular stroke treatment due to an acute ischemic stroke of the anterior circulation, no significant difference was seen between the individualized BP management strategy, where intraprocedural SBP was targeted to baseline values, and the standardized regimen of targeting SBP between 140 and 180 mm Hg. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT04578288.

First application of dynamic oxygen-17 magnetic resonance imaging at 7 Tesla in a patient with early subacute stroke.

Dynamic oxygen-17 (17O) magnetic resonance imaging (MRI) is an imaging method that enables a direct and non-invasive assessment of cerebral oxygen metabolism and thus potentially the distinction between viable and non-viable tissue employing a three-phase inhalation experiment. The purpose of this investigation was the first application of dynamic 17O MRI at 7 Tesla (T) in a patient with stroke. In this proof-of-concept experiment, dynamic 17O MRI was applied during 17O inhalation in a patient with early subacute stroke. The analysis of the relative 17O water (H217O) signal for the affected stroke region compared to the healthy contralateral side revealed no significant difference. However, the technical feasibility of 17O MRI has been demonstrated paving the way for future investigations in neurovascular diseases.

Clinical outcome, recanalization success, and time metrics in drip-and-ship vs. drive-the-doctor: A retrospective analysis of the HEI-LU-Stroke registry.

Purpose: This study aimed at comparing clinical outcome, recanalization success and time metrics in the "drip and ship" (DS) vs. "drive the doctor" (DD) concept in a comparable setting. Methods: This is a retrospective analysis of thrombectomy registries of a comprehensive stroke center (CSC) and a thrombectomy-capable stroke center (TSC). Patients, who were transferred from the TSC to the CSC, were classified as DS. Patients treated at the TSC by an interventionalist transferred from the CSC were classified as DD. Good outcome was defined as mRS 0-2 or equivalent to premorbid mRS at discharge. Recanalization (TICI 2b-3 or equivalent) and time metrics were compared in both groups. Results: In total, 295 patients were included, of which 116 (39.3%) were treated in the DS concept and 179 (60.7%) in the DD concept. Good clinical outcome was similarly achieved in DS and DD (DS 25.0% vs. DD 31.3%, P = 0.293). mRS on discharge (DS median 4, DD median 4, P = 0.686), NIHSS improvement (DS median 4, DD median 5, P = 0.582) and NIHSS on discharge (DS median 9, DD median 7, P = 0.231) were similar in both groups. Successful reperfusion was achieved similarly in DS (75.9%) and DD as well (81.0%, P = 0.375). Time from onset to reperfusion (median DS 379 vs. DD 286 min, P = 0.076) and time from initial imaging to reperfusion were longer in DS compared to DD (median DS 246 vs. DD 162 min, P < 0.001). Conclusion: The DD concept is time saving while achieving similar clinical outcome and recanalization results.

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.

Exact Basilar Artery Occlusion Location Indicates Stroke Etiology and Recanalization Success in Patients Eligible for Endovascular Stroke Treatment.

INTRODUCTION: Endovascular stroke treatment (EST) is commonly performed for acute basilar artery occlusion (BAO). We aimed to identify the role of the exact location of BAO in patients receiving EST regarding the stroke etiology, recanalization success and prediction of favorable clinical outcome. METHODS: Retrospective analysis of 191 consecutive patients treated for BAO with EST from 01/2013 until 06/2021 in a tertiary stroke center. Groups were defined according to exact location of BAO in I: proximal third, II: middle third, III: distal third and IV: tip of the basilar artery. Univariate and multivariate analyses were performed for BAO location comparing stroke etiology, recanalization result and favorable clinical outcome according to mRS 0-3 90 days after stroke onset. RESULTS: Occlusion sides types I-IV were evenly distributed (37, 36, 60 and 58 patients). Types I and II were more often associated with large artery atherosclerosis (50 vs. 10 patients, p < 0.001). Distal/tip occlusion (types III/IV) occurred mostly in cardiac embolism or embolic stroke of unknown source (89 vs. 12 in types I/II, p < 0.001). Occlusion site correlated with the underlying stroke etiology (AUC [Area under the curve] 0.89, p < 0.0001, OR [odds ratio] for embolism in type IV: 245). Recanalization rates were higher in patients with distal occlusions (type III/IV OR 3.76, CI [95% confidence interval] 1.51-9.53, p = 0.0076). The BAO site is not predicting favorable clinical outcome. CONCLUSION: The exact basilar artery occlusion site in patients eligible for endovascular stroke treatment reflects the stroke etiology and is associated with differing recanalization success but does not predict favorable clinical outcome.

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.

Perfusion Imaging and Clinical Outcome in Acute Minor Stroke With Large Vessel Occlusion.

BACKGROUND: Whether bridging therapy (intravenous thrombolysis [IVT] followed by mechanical thrombectomy) is superior to IVT alone in minor stroke with large vessel occlusion is unknown. Perfusion imaging may identify subsets of large vessel occlusion-related minor stroke patients with distinct response to bridging therapy. METHODS: We conducted a multicenter international observational study of consecutive IVT-treated patients with minor stroke (National Institutes of Health Stroke Scale score ≤5) who had an anterior circulation large vessel occlusion and perfusion imaging performed before IVT, with a subset undergoing immediate thrombectomy. Propensity score with inverse probability of treatment weighting was used to account for baseline between-groups differences. The primary outcome was 3-month modified Rankin Scale score 0 to 1. We searched for an interaction between treatment group and mismatch volume (critical hypoperfusion-core volume). RESULTS: Overall, 569 patients were included (172 and 397 in the bridging therapy and IVT groups, respectively). After propensity-score weighting, the distribution of baseline variables was similar across the 2 groups. In the entire population, bridging was associated with lower odds of achieving modified Rankin Scale score 0 to 1: odds ratio, 0.73 [95% CI, 0.55-0.96]; P=0.03. However, mismatch volume modified the effect of bridging on clinical outcome (Pinteraction=0.04 for continuous mismatch volume); bridging was associated with worse outcome in patients with, but not in those without, mismatch volume <40 mL (odds ratio, [95% CI] for modified Rankin Scale score 0-1: 0.48 [0.33-0.71] versus 1.14 [0.76-1.71], respectively). Bridging was associated with higher incidence of symptomatic intracranial hemorrhage in the entire population, but this effect was present in the small mismatch subset only (Pinteraction=0.002). CONCLUSIONS: In our population of large vessel occlusion-related minor stroke patients, bridging therapy was associated with lower rates of good outcome as compared with IVT alone. However, mismatch volume was a strong modifier of the effect of bridging therapy over IVT alone, notably with worse outcome with bridging therapy in patients with mismatch volume ≤40 mL. Randomized trials should consider adding perfusion imaging for patient selection.

Comparing Poor and Favorable Outcome Prediction With Machine Learning After Mechanical Thrombectomy in Acute Ischemic Stroke.

Background and Purpose: Outcome prediction after mechanical thrombectomy (MT) in patients with acute ischemic stroke (AIS) and large vessel occlusion (LVO) is commonly performed by focusing on favorable outcome (modified Rankin Scale, mRS 0-2) after 3 months but poor outcome representing severe disability and mortality (mRS 5 and 6) might be of equal importance for clinical decision-making. Methods: We retrospectively analyzed patients with AIS and LVO undergoing MT from 2009 to 2018. Prognostic variables were grouped in baseline clinical (A), MRI-derived variables including mismatch [apparent diffusion coefficient (ADC) and time-to-maximum (Tmax) lesion volume] (B), and variables reflecting speed and extent of reperfusion (C) [modified treatment in cerebral ischemia (mTICI) score and time from onset to mTICI]. Three different scenarios were analyzed: (1) baseline clinical parameters only, (2) baseline clinical and MRI-derived parameters, and (3) all baseline clinical, imaging-derived, and reperfusion-associated parameters. For each scenario, we assessed prediction for favorable and poor outcome with seven different machine learning algorithms. Results: In 210 patients, prediction of favorable outcome was improved after including speed and extent of recanalization [highest area under the curve (AUC) 0.73] compared to using baseline clinical variables only (highest AUC 0.67). Prediction of poor outcome remained stable by using baseline clinical variables only (highest AUC 0.71) and did not improve further by additional variables. Prediction of favorable and poor outcomes was not improved by adding MR-mismatch variables. Most important baseline clinical variables for both outcomes were age, National Institutes of Health Stroke Scale, and premorbid mRS. Conclusions: Our results suggest that a prediction of poor outcome after AIS and MT could be made based on clinical baseline variables only. Speed and extent of MT did improve prediction for a favorable outcome but is not relevant for poor outcome. An MR mismatch with small ischemic core and larger penumbral tissue showed no predictive importance.

Leaving the day behind: endovascular therapy beyond 24 h in acute stroke of the anterior and posterior circulation.

Background: There is little evidence of endovascular therapy (EVT) being performed in acute ischemic stroke beyond 24 h, and that evidence is limited to anterior circulation stroke. Objective: To extend evidence of efficacy and safety of EVT after more than 24 h in both anterior and posterior circulation stroke. Methods: Local, prospectively collected registries were screened for patients with acute ischemic stroke and large-vessel occlusion who had received either EVT > 24 h after last-seen-well but <24 h after symptom recognition (EVT>24LSW) or EVT > 24 h since first (definitive) symptom recognition (EVT>24DEF). Patients treated <24 h served as a group for comparison. Favorable outcome was defined as modified Rankin scale (mRS) 0-2 or return to prestroke mRS at 3 months. Results: Between January 2014 and August 2021, N = 2347 were treated with EVT at our comprehensive stroke center, of whom n = 43 met the inclusion criteria (EVT>24LSW, n = 16, EVT>24DEF, n = 27). EVT>24LSW patients were treated at a median of 28.7 h [interquartile range (IQR) = 27.3-32.8] after last-seen-well and 7.3 h (IQR = 2.8-14.3) after symptom recognition; EVT>24DEF patients were treated 52.5 h (IQR = 26.5-94.2) after first symptoms. Favorable outcome was achieved by 23.3% (10/43) in the EVT > 24 compared with 39.4% (886/2250) in the EVT < 24 group (p = 0.04). Bleeding rates were similar across groups. Mortality was also similar [EVT > 24, 27.9% (12/43) versus EVT < 24, 25.7% (584/2264), p = 0.727; posterior circulation, EVT > 24, 41.7% (5/12) versus EVT < 24, 36.5% (92/252) p = 0.764]. Conclusion: In selected patients, EVT seems effective and safe beyond 24 h for both anterior and posterior circulation stroke.

What is the impact of head movement on automated CT perfusion mismatch evaluation in acute ischemic stroke?

OBJECTIVES: Automated CT perfusion mismatch assessment is an established treatment decision tool in acute ischemic stroke. However, the reliability of this method in patients with head motion is unclear. We therefore sought to evaluate the influence of head movement on automated CT perfusion mismatch evaluation. METHODS: Using a realistic CT brain-perfusion-phantom, 7 perfusion mismatch scenarios were simulated within the left middle cerebral artery territory. Real CT noise and artificial head movement were added. Thereafter, ischemic core, penumbra volumes and mismatch ratios were evaluated using an automated mismatch analysis software (RAPID, iSchemaView) and compared with ground truth simulated values. RESULTS: While CT scanner noise alone had only a minor impact on mismatch evaluation, a tendency towards smaller infarct core estimates (mean difference of -5.3 (-14 to 3.5) mL for subtle head movement and -7.0 (-14.7 to 0.7) mL for strong head movement), larger penumbral estimates (+9.9 (-25 to 44) mL and +35 (-14 to 85) mL, respectively) and consequently larger mismatch ratios (+0.8 (-1.5 to 3.0) for subtle head movement and +1.9 (-1.3 to 5.1) for strong head movement) were noted in dependence of patient head movement. CONCLUSIONS: Motion during CT perfusion acquisition influences automated mismatch evaluation. Potentially treatment-relevant changes in mismatch classifications in dependence of head movement were observed and occurred in favor of mechanical thrombectomy.

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.

Sedation Mode During Endovascular Stroke Treatment in the Posterior Circulation-Is Conscious Sedation for Eligible Patients Feasible?

Background and Purpose: To compare safety and efficacy of conscious sedation (CS) vs. general anesthesia (GA) in endovascular stroke treatment (EST) of the posterior circulation (PC). Methods: Retrospective single-center analysis of patients receiving EST for large-vessel occlusion (LVO) in PC between January 2015 and November 2020. Exclusion criteria were severe stroke syndromes (NIHSS > 20), decreased level of consciousness, intubation for transport, and second stroke within 3 months of follow-up. The primary endpoint was a favorable clinical outcome 90 days after stroke onset (mRS 0-2 or 3 if pre-stroke mRS 3). Secondary endpoints were the rate of EST failure and procedural complications. Results: Of 111 included patients, 45/111 patients (40.5%) were treated under CS and 60/111 (54.0%) under GA. In 6/111 cases (5.4%), sedation mode was changed from CS to GA during EST. Patients treated under CS showed a lower mRS 90 days after stroke onset [mRS, median (IQR): 2.5 (1-4) CS vs. 3 (2-6) GA, p = 0.036] and a comparable rate of good outcome [good outcome, n (%): 19 (42.2) CS vs. 15 (32.6) GA, p = 0.311]. There was no difference in complication rates during EST (6.7% CS vs. 8.3% GA) or intracranial bleeding in follow-up imaging [n (%): 4 (8.9) CS vs. 7 (11.7) GA), p = 0.705]. The rate of successful target vessel recanalization did not differ (84.4% CS vs. 85.0 % GA). Conclusions: In this retrospective study, EST of the posterior circulation under conscious sedation was for eligible patients comparably safe and effective to patients treated under general anesthesia.

Accuracy and reliability of PBV ASPECTS, CBV ASPECTS and NCCT ASPECTS in acute ischaemic stroke: a matched-pair analysis.

BACKGROUND AND PURPOSE: To investigate the reliability and accuracy of Alberta Stroke Program Early Computed Tomography Scores (ASPECTS) derived from flatpanel detector computed tomography pooled blood volume maps compared to non-contrast computed tomography and multidetector computed tomography perfusion cerebral blood volume maps. METHODS: ASPECTS from pooled blood volume maps were evaluated retrospectively by two experienced readers for 37 consecutive patients with acute middle cerebral artery (MCA) M1 occlusion who underwent flatpanel detector computed tomography perfusion imaging before mechanical thrombectomy between November 2016 and February 2019. For comparison with ASPECTS from non-contrast computed tomography and cerebral blood volume maps, a matched-pair analysis according to pre-stroke modified Rankin scale, age, stroke severity, site of occlusion, time from stroke onset to imaging and final modified thrombolysis in cerebral infarction (mTICI) was performed in a separate group of patients who underwent multimodal computed tomography prior to mechanical thrombectomy between June 2015 and February 2019. Follow-up ASPECTS were derived from either non-contrast computed tomography or from magnetic resonance imaging (in seven patients) one day after mechanical thrombectomy. RESULTS: Interrater agreement was best for non-contrast computed tomography ASPECTS (w-kappa = 0.74, vs. w-kappa = 0.63 for cerebral blood volume ASPECTS and w-kappa = 0.53 for pooled blood volume ASPECTS). Also, accuracy, defined as correlation between acute and follow-up ASPECTS, was best for non-contrast computed tomography ASPECTS (Spearman ρ = 0.86 (0.65-0.97), P < 0.001), while it was lower and comparable for pooled blood volume ASPECTS (ρ = 0.58 (0.32-0.79), P < 0.001) and cerebral blood volume ASPECTS (ρ = 0.52 (0.17-0.80), P = 0.001). It was noteworthy that cases of relevant infarct overestimation by two or more ASPECTS regions (compared to follow-up imaging) were observed for both acute pooled blood volume and cerebral blood volume ASPECTS but occurred more often for acute pooled blood volume ASPECTS (25% vs. 5%, P = 0.02). CONCLUSION: Non-contrast computed tomography ASPECTS outperformed both pooled blood volume ASPECTS and cerebral blood volume ASPECTS in accuracy and reliability. Importantly, relevant infarct overestimation was observed more often in pooled blood volume ASPECTS than cerebral blood volume ASPECTS, limiting its present clinical applicability for acute stroke imaging.

Combined Perfusion and Permeability Imaging Reveals Different Pathophysiologic Tissue Responses After Successful Thrombectomy.

Despite successful recanalization of large-vessel occlusions in acute ischemic stroke, individual patients profit to a varying degree. Dynamic susceptibility-weighted perfusion and dynamic T1-weighted contrast-enhanced blood-brain barrier permeability imaging may help to determine secondary stroke injury and predict clinical outcome. We prospectively performed perfusion and permeability imaging in 38 patients within 24 h after successful mechanical thrombectomy of an occlusion of the middle cerebral artery M1 segment. Perfusion alterations were evaluated on cerebral blood flow maps, blood-brain barrier disruption (BBBD) visually and quantitatively on ktrans maps and hemorrhagic transformation on susceptibility-weighted images. Visual BBBD within the DWI lesion corresponded to a median ktrans elevation (IQR) of 0.77 (0.41-1.4) min-1 and was found in all 7 cases of hypoperfusion (100%), in 10 of 16 cases of hyperperfusion (63%), and in only three of 13 cases with unaffected perfusion (23%). BBBD was significantly associated with hemorrhagic transformation (p < 0.001). While BBBD alone was not a predictor of clinical outcome at 3 months (positive predictive value (PPV) = 0.8 [0.56-0.94]), hypoperfusion occurred more often in patients with unfavorable clinical outcome (PPV = 0.43 [0.10-0.82]) compared to hyperperfusion (PPV = 0.93 [0.68-1.0]) or unaffected perfusion (PPV = 1.0 [0.75-1.0]). We show that combined perfusion and permeability imaging reveals distinct infarct signatures after recanalization, indicating the severity of prior ischemic damage. It assists in predicting clinical outcome and may identify patients at risk of stroke progression.

Reasons for Failed Mechanical Thrombectomy in Posterior Circulation Ischemic Stroke Patients.

BACKGROUND AND PURPOSE: To determine reasons for failed recanalization in mechanical thrombectomy (MT) of the posterior circulation. METHODS: Retrospective single center analysis of reasons for MT failure in the posterior circulation. Failed MTs were categorized according to the reason for procedure failure in failed vascular access, failed passage of the target vessel occlusion and MT failure after passing the occluded target vessel. Patient characteristics were compared between failed and successful MT. RESULTS: Patients with failed MT (30/218 patients, 13.8%) were categorized into futile vascular access (13/30, 43.3%), abortive passage of the target vessel occlusion (6/30, 20.0%) and MT failure after passing the vessel occlusion (11/30, 36.7%). In 188/218 (86.2%) successful MTs alternative vascular access, local intra-arterial (i.a.) thrombolysis and emergency stent-assisted PTA prevented 65 MT failures. Patients with failed MT showed a higher NIHSS at discharge, a higher pc-ASPECTS in follow-up imaging, a higher mRS 90 days after stroke onset and a high mortality rate of 77.0% (mRS at 90 days, median (IQR): 6 (6-6) vs. 4 (2-6) for successful MT, p-value < 0.001). Co-morbidities and stroke etiology were not different compared to sufficient recanalization with atherosclerotic disease as the leading stroke etiology in both groups. CONCLUSION: Failure of MT in posterior circulation ischemic stroke patients is associated with a high mortality rate. Reasons for MT failure are diverse with futile vascular access and MT failure after passing the vessel occlusion as the leading causes. Alternative vascular access, local i.a. thrombolysis and stent-assisted PTA can prevent MT failure.

Radiation exposure in endovascular stroke treatment of acute basilar artery occlusions-a matched-pair analysis.

PURPOSE: To determine the radiation exposure in endovascular stroke treatment (EST) of acute basilar artery occlusions (BAO) and compare it with radiation exposure of EST for embolic middle cerebral artery occlusions (MCAO). METHODS: In this retrospective analysis of an institutional review board-approved prospective stroke database of a comprehensive stroke center, we focused on radiation exposure (as per dose area product in Gy × cm2, median (IQR)), procedure time, and fluoroscopy time (in minutes, median [IQR]) in patients receiving EST for BAO. Patients who received EST for BAO were matched case by case with patients who received EST for MCAO according to number of thrombectomy attempts, target vessel reperfusion result, and thrombectomy technique. RESULTS: Overall 180 patients (n = 90 in each group) were included in this analysis. General anesthesia was conducted more often during EST of BAO (BAO: 75 (83.3%); MCAO: 18 (31.1%), p < 0.001). Procedure time (BAO: 31 (20-43); MCAO: 27 (18-38); p value 0.226) and fluoroscopy time (BAO: 29 (20-59); MCAO: 29 (17-49), p value 0.317) were comparable. Radiation exposure was significantly higher in patients receiving EST for BAO (BAO: 123.4 (78.7-204.2); MCAO: 94.3 (65.5-163.7), p value 0.046), which represents an increase by 23.7%. CONCLUSION: Endovascular stroke treatment of basilar artery occlusions is associated with a higher radiation exposure compared with treatment of middle cerebral artery occlusions.

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.

Correlation of Tmax volumes with clinical outcome in anterior circulation stroke.

BACKGROUND AND PURPOSE: The recent thrombectomy trials have shown that perfusion imaging is helpful in proper patient selection in thromboembolic stroke. In this study, we analyzed the correlation of pretreatment Tmax volumes in MR and CT perfusion with clinical outcome after thrombectomy. METHODS: Forty-one consecutive patients with middle cerebral artery occlusion (MCA) or carotid T occlusion treated with thrombectomy were included. Tmax volumes at delays of >4, 6, 8, and 10 s as well as infarct core and mismatch ratio were automatically estimated in preinterventional MRI or CT perfusion using RAPID software. These perfusion parameters were correlated with clinical outcome. Outcome was assessed using modified Rankin scale at 90 days. RESULTS: In patients with successful recanalization of MCA occlusion, Tmax > 8 and 10 s showed the best linear correlation with clinical outcome (r = 0.75; p = .0139 and r = 0.73; p = .0139), better than infarct core (r = 0.43; p = .2592). In terminal internal carotid artery occlusions, none of the perfusion parameters showed a significant correlation with clinical outcome. CONCLUSIONS: Tmax at delays of >8 and 10 s is a good predictor for clinical outcome in MCA occlusions. In carotid T occlusion, however, Tmax volumes do not correlate with outcome.