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.

[Comparison of acute stroke care pathways-A qualitative multicenter study in three referring hospitals of a stroke network]

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.

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 Whitney‑U 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.

MR microscopy to assess clot composition following mechanical thrombectomy predicts recanalization and clinical outcome

BACKGROUND

Mechanical thrombectomy (MT) is the standard of care for patients with a stroke and large vessel occlusion. Clot composition is not routinely assessed in clinical practice as no specific diagnostic value is attributed to it, and MT is performed in a standardized 'non-personalized' approach. Whether different clot compositions are associated with intrinsic likelihoods of recanalization success or treatment outcome is unknown.

METHODS

We performed a prospective, non-randomized, single-center study and analyzed the clot composition in 60 consecutive patients with ischemic stroke undergoing MT. Clots were assessed by ex vivo multiparametric MRI at 9.4 T (MR microscopy), cone beam CT, and histopathology. Clot imaging was correlated with preinterventional CT and clinical data.

RESULTS

MR microscopy showed red blood cell (RBC)-rich (21.7%), platelet-rich (white,38.3%) or mixed clots (40.0%) as distinct morphological entities, and MR microscopy had high accuracy of 95.4% to differentiate clots. Clot composition could be further stratified on preinterventional non-contrast head CT by quantification of the hyperdense artery sign. During MT, white clots required more passes to achieve final recanalization and were not amenable to contact aspiration compared with mixed and RBC-rich clots (maneuvers: 4.7 vs 3.1 and 1.2 passes, P<0.05 and P<0.001, respectively), whereas RBC-rich clots showed higher probability of first pass recanalization (76.9%) compared with white clots (17.4%). White clots were associated with poorer clinical outcome at discharge and 90 days after MT.

CONCLUSION

Our study introduces MR microscopy to show that the hyperdense artery sign or MR relaxometry could guide interventional strategy. This could enable a personalized treatment approach to improve outcome of patients undergoing MT.

Occupational radiation exposure of neurointerventionalists during endovascular stroke treatment

BACKGROUND

Radiological neuro-interventions, especially endovascular stroke treatment (EST), are increasing in case numbers worldwide with increasing occupational radiation exposure. Aim of this study was to define the radiation exposure of neurointerventionalists (NI) during EST and to compare the accumulated dose reaching the left arm with the left temple.

METHODS

This is a prospective observational study in a tertiary stroke center conducted between 11/2021 and 07/2022. Radiation exposure was measured using real time dosimetry with dosimeters being carried by the NI during EST simultaneously at the left temple and left arm. The effective dose [µSV] per dose area product (DAP) and potential influencing factors were compared in univariate analysis between the two dosimeter positions.

RESULTS

In total, 82 ESTs were analyzed with a median DAP of 6179 µGy*m² (IQR 3271 µGy*m²-11720 µGy*m²). The accumulated dose at the left arm and left temple correlated with the DAP and fluoroscopy time of the EST (DAP and arm: p = 0.01, DAP and temple: p = 0.006). The radiation exposure (RE) showed a wide range and did not differ between the two dosimeter positions (median, IQR arm 7 µSV, IQR 3.1-16.9 µSV, min. 0.3 µSV max. 64.5 µSV) vs. head 7 µSv, IQR 3.2-17.4 µSV, min. 0.38 µSV, max. 48.6 µSV, p = 0.94). Occupational RE depends on the number of thrombectomy attempts, but not the target vessel occlusion location or the NI's body height.

CONCLUSION

Neurointerventionalists experience a generally low but very variable radiation exposure during EST, which depends on the intervention's fluoroscopy time and dose area product as well as thrombectomy attempts but does not differ between left temple and left arm.

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 &lt; 0.001).

Conclusion

The DD concept is time saving while achieving similar clinical outcome and recanalization results.

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.

Endovascular vs Medical Management for Late Anterior Large Vessel Occlusion With Prestroke Disability: Analysis of CLEAR and RESCUE-Japan

BACKGROUND AND OBJECTIVES

Current guidelines do not address recommendations for mechanical thrombectomy (MT) in the extended time window (>6 hours after time last seen well [TLSW]) for large vessel occlusion (LVO) patients with preexisting modified Rankin Scale (mRS) > 1. In this study, we evaluated the outcomes of MT vs medical management in patients with prestroke disability presenting in the 6- to 24-hour time window with acute LVO.

METHODS

We analyzed a multinational cohort (61 sites, 6 countries from 2014 to 2020) of patients with prestroke (or baseline) mRS 2 to 4 and anterior circulation LVO treated 6-24 hours from TLSW. Patients treated in the extended time window with MT vs medical management were compared using multivariable logistic regression and inverse probability of treatment weighting (IPTW). The primary outcome was the return of Rankin (ROR, return to prestroke mRS by 90 days).

RESULTS

Of 554 included patients (448 who underwent MT), the median age was 82 years (interquartile range [IQR] 72-87) and the National Institutes of Health Stroke Scale (NIHSS) was 18 (IQR 13-22). In both MV logistic regression and IPTW analysis, MT was associated with higher odds of ROR (adjusted OR [aOR] 3.96, 95% CI 1.78-8.79 and OR 3.10, 95% CI 1.20-7.98, respectively). Among other factors, premorbid mRS 4 was associated with higher odds of ROR (aOR, 3.68, 95% CI 1.97-6.87), while increasing NIHSS (aOR 0.90, 95% CI 0.86-0.94) and decreasing Alberta Stroke Program Early Computed Tomography Scale score (aOR per point 0.86, 95% CI 0.75-0.99) were associated with lower odds of ROR. Age, intravenous thrombolysis, and occlusion location were not associated with ROR.

DISCUSSION

In patients with preexisting disability presenting in the 6- to 24-hour time window, MT is associated with a higher probability of returning to baseline function compared with medical management.

CLASSIFICATION OF EVIDENCE

This investigation's results provide Class III evidence that in patients with preexisting disability presenting 6-24 hours from the TLSW and acute anterior LVO stroke, there may be a benefit of MT over medical management in returning to baseline function.

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.

RAPID CT Perfusion-Based Relative CBF Identifies Good Collateral Status Better Than Hypoperfusion Intensity Ratio, CBV-Index, and Time-to-Maximum in Anterior Circulation Stroke

BACKGROUND AND PURPOSE

Information of collateral flow may help to determine eligibility for thrombectomy. Our aim was to identify CT perfusion-based surrogate parameters of good collateral status in acute anterior circulation ischemic stroke.

MATERIALS AND METHODS

In this retrospective study, we assessed the collateral status of 214 patients who presented with acute ischemic stroke due to occlusion of the MCA M1 segment or the carotid terminus. Collaterals were assessed on dynamic CTA images analogous to the multiphase CTA score by Menon et al. CT perfusion parameters (time-to-maximum, relative CBF, hypoperfusion intensity ratio, and CBV-index) were assessed with RAPID software. The Spearman rank correlation and receiver operating characteristic analyses were performed to identify the parameters that correlate with collateral scores and good collateral supply (defined as a collateral score of ≥4).

RESULTS

The Spearman rank correlation was highest for a relative CBF < 38% volume (ρ = -0.66, P < .001), followed by the hypoperfusion intensity ratio (ρ = -0.49, P < .001), CBV-index (ρ = 0.51, P < .001), and time-to-maximum > 8 seconds (ρ = -0.54, P < .001). Good collateral status was better identified by a relative CBF < 38% at a lesion size <27 mL (sensitivity of 75%, specificity of 80%) compared with a hypoperfusion intensity ratio of <0.4 (sensitivity of 75%, specificity of 62%), CBV-index of >0.8 (sensitivity of 60%, specificity of 78%), and time-to-maximum > 8 seconds (sensitivity of 68%, specificity of 76%).

CONCLUSIONS

Automated CT perfusion analysis allows accurate identification of collateral status in acute ischemic stroke. A relative CBF < 38% may be a better perfusion-based indicator of good collateral supply compared with time-to-maximum, the hypoperfusion intensity ratio, and the CBV-index.

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.

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.

Abstract TMP67: Predictors Of Unfavourable Events Despite Successful Mechanical Thrombectomy In The Extended Window

Background: Futile recanalization (FR) and symptomatic intracranial hemorrhage (sICH) are adverse outcomes after otherwise successful mechanical thrombectomy (MT). The aim of this study was to evaluate independent predictors of these unfavourable events in the extended time window and to compare imaging modalities (non-enhanced CT (NCCT) alone vs. CT perfusion vs. MRI) regarding patient selection.

Methods: The CT for Late EndovasculAr Reperfusion (CLEAR) study was a multicenter, retrospective study of stroke patients undergoing thrombectomy in the extended time window. The primary endpoint of this study was the proportion of patients with FR, defined as a patient with large vessel occlusion achieving near-complete or complete reperfusion (TICI 2c/3) with a 90-day mRS score between 3 and 6. The secondary safety endpoints included the predictors of mortality and symptomatic intracranial hemorrhage. Inclusion criteria for this analysis were baseline NIHSS ≥6, internal carotid artery, M1 or M2 segment occlusion, prestroke modified rankin scale (pmRS) 0-2, time last seen well (TLSW) to treatment 6-24 hours, and mTICI 2c-3.

Results: Of 2304 patients in the CLEAR study, 715 patients were included in this analysis. Of these, 364 patients (50.9%) showed FR, 37 patients (5.2%) suffered sICH and 127 patients (17.8%) died within 90 days. Old age, higher baseline NIHSS, higher prestroke disability, transfer to a comprehensive stroke center from another site, and a longer interval from TLSW to puncture were identified as positive predictors of FR. Hypertension was an independent predictor of sICH. The imaging modality (NCCT vs. CT perfusion vs. MRI) was not associated with FR, sICH, or mortality.

Conclusions: Older age, higher baseline NIHSS, higher prestroke disability, transfer patients, and a longer interval from TLSW to puncture were predictors of FR in the extended window. Hypertension was a predictor of sICH in successfully reperfused patients. Neither MRI or CT perfusion was superior in predicting FR and sICH compared to NCCT alone. NCCT together with CTA may be sufficient for patient selection in the extended time window.

Trial Registration: ClinicalTrials.gov Identifier: NCT04096248

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.

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.

Noncontrast Computed Tomography vs Computed Tomography Perfusion or Magnetic Resonance Imaging Selection in Late Presentation of Stroke With Large-Vessel Occlusion

Question

In patients with proximal anterior circulation occlusion stroke presenting in the extended window, are rates of favorable outcomes at 90 days comparable in the patients selected for thrombectomy with noncontrast computed tomography vs patients selected with computed tomography perfusion or magnetic resonance imaging?

Findings

In a multicenter cohort of 1604 patients in the extended window with large-vessel occlusion, patients selected by noncontrast computed tomography had comparable clinical and safety outcomes with patients selected by computed tomography perfusion or magnetic resonance imaging.

Meaning

These findings suggest noncontrast computed tomography alone may be used as an alternative to advanced imaging in selecting patients with late-presenting large-vessel occlusion for mechanical thrombectomy.

Importance

Advanced imaging for patient selection in mechanical thrombectomy is not widely available.

Objective

To compare the clinical outcomes of patients selected for mechanical thrombectomy by noncontrast computed tomography (CT) vs those selected by computed tomography perfusion (CTP) or magnetic resonance imaging (MRI) in the extended time window.

Design, Setting, and Participants

This multinational cohort study included consecutive patients with proximal anterior circulation occlusion stroke presenting within 6 to 24 hours of time last seen well from January 2014 to December 2020. This study was conducted at 15 sites across 5 countries in Europe and North America. The duration of follow-up was 90 days from stroke onset.

Exposures

Computed tomography with Alberta Stroke Program Early CT Score, CTP, or MRI.

Main Outcomes and Measures

The primary end point was the distribution of modified Rankin Scale (mRS) scores at 90 days (ordinal shift). Secondary outcomes included the rates of 90-day functional independence (mRS scores of 0-2), symptomatic intracranial hemorrhage, and 90-day mortality.

Results

Of 2304 patients screened for eligibility, 1604 patients were included, with a median (IQR) age of 70 (59-80) years; 848 (52.9%) were women. A total of 534 patients were selected to undergo mechanical thrombectomy by CT, 752 by CTP, and 318 by MRI. After adjustment of confounders, there was no difference in 90-day ordinal mRS shift between patients selected by CT vs CTP (adjusted odds ratio [aOR], 0.95 [95% CI, 0.77-1.17]; P = .64) or CT vs MRI (aOR, 0.95 [95% CI, 0.8-1.13]; P = .55). The rates of 90-day functional independence (mRS scores 0-2 vs 3-6) were similar between patients selected by CT vs CTP (aOR, 0.90 [95% CI, 0.7-1.16]; P = .42) but lower in patients selected by MRI than CT (aOR, 0.79 [95% CI, 0.64-0.98]; P = .03). Successful reperfusion was more common in the CT and CTP groups compared with the MRI group (474 [88.9%] and 670 [89.5%] vs 250 [78.9%]; P < .001). No significant differences in symptomatic intracranial hemorrhage (CT, 42 [8.1%]; CTP, 43 [5.8%]; MRI, 15 [4.7%]; P = .11) or 90-day mortality (CT, 125 [23.4%]; CTP, 159 [21.1%]; MRI, 62 [19.5%]; P = .38) were observed.

Conclusions and Relevance

In patients undergoing proximal anterior circulation mechanical thrombectomy in the extended time window, there were no significant differences in the clinical outcomes of patients selected with noncontrast CT compared with those selected with CTP or MRI. These findings have the potential to widen the indication for treating patients in the extended window using a simpler and more widespread noncontrast CT–only paradigm.

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.

"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.

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.

Efficacy and safety of bridging thrombolysis initiated before transfer in a drip-and-ship stroke service

Objective

Data regarding the efficacy and safety of bridging thrombolysis (BT) initiated before transfer for evaluation of endovascular therapy is heterogeneous. We, therefore, analyse efficacy and safety of BT in patients treated within a drip-and-ship stroke service.

Methods

Consecutive adult patients suffering from acute ischaemic stroke and large-vessel occlusions (LVO) transferred to our comprehensive stroke centre for evaluation of endovascular therapy in 2017–2020 were identified from a local prospective stroke database and categorised according to BT and no-BT. BT was defined as intravenous thrombolysis initiated before transfer. LVO was assessed before and after transfer. Functional outcome before stroke and at 3 months using the modified Rankin scale (mRS) was determined. Excellent outcome was defined as mRS 0–1 or return to prestroke mRS. For safety analysis, intracranial haemorrhages and mortality at 3 months were analysed. Main analysis was limited to patients with anterior circulation stroke.

Results

Of N=714 patients, n=394 (55.2%) received BT. More patients in the BT group with documented LVO before transfer recanalised without endovascular therapy (n=46, 11.7%) than patients who did not receive BT before transfer (n=4, 1.3%, p<0.001). In multivariate analysis, BT was the strongest independent predictor of early recanalisation (adjusted OR 10.9, 95% CI 3.8 to 31.1, p<0.001). BT tended to be an independent predictor of an excellent outcome at 3 months (adjusted OR 1.38, 95% CI 0.97 to 1.96, p=0.077). There were no differences in safety between the BT and no-BT groups.

Conclusions

BT initiated before transfer was a strong independent predictor of early recanalisation.

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.

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.

Diagnostic accuracy of automated occlusion detection in CT angiography using e-CTA

Background and aim

The aim of this study was to assess the diagnostic accuracy of e-CTA (product name) (Brainomix) in the automatic detection of large vessel occlusions in anterior circulation stroke.

Methods

Of 487 CT angiographies from patients with large vessel occlusions stroke, 327 were used to train the algorithm while the remaining cases together with 140 negative CT angiographies were used to validate its performance against ground truth. Of these 301 cases, 144 were randomly selected and used for an additional comparative analysis against 4 raters. Sensitivity, specificity, positive and negative predictive value (PPV and NPV), accuracy and level of agreement with ground truth (Cohen’s Kappa) were determined and compared to the performance of a neuroradiologist, a radiology resident, and two neurology residents.

Results

e-CTA had a sensitivity and specificity of 0.84 (0.77–0.89) and 0.96 (0.91–0.98) respectively for the detection of any large vessel occlusions on the correct side in the whole validation cohort. This performance was identical in the comparative analysis subgroup and was within the range of physicians at different levels of expertise: 0.86–0.97 and 0.91–1.00, respectively. For the detection of proximal occlusions, it was 0.92 (0.84–0.96) and 0.98 (0.94–1.00) for the whole cohort and 0.93 (0.80–0.98) and 1.00 (0.95–1.00) for the comparative analysis, respectively for e-CTA. The range was 0.8–0.97 for sensitivity and 0.97–1.00 for specificity for the four physicians.

Conclusions

The performance of e-CTA in detecting any large vessel occlusions is comparable to less experienced physicians but is similar to experienced physicians for detecting proximal large vessel occlusions.

Imaging Artifacts of Liquid Embolic Agents on Conventional CT in an Experimental in Vitro Model

BACKGROUND AND PURPOSE

Endovascular embolization using liquid embolic agents is a safe and effective treatment option for AVMs and dural arteriovenous fistulas. The aim of this study was to assess the degree of artifact inducement by the most frequently used liquid embolic agents in conventional CT in an experimental in vitro model.

MATERIALS AND METHODS

Dimethyl-sulfoxide-compatible tubes were filled with the following liquid embolic agents (n = 10, respectively): Onyx 18, all variants of Squid, PHIL 25%, PHIL LV, and n-BCA mixed with iodized oil. After inserting the tubes into a CT imaging phantom, we acquired images. Artifacts were graded quantitatively by the use of Hounsfield units in a donut-shaped ROI using a customized software application that was specifically designed for this study and were graded qualitatively using a 5-point scale.

RESULTS

Quantitative and qualitative analyses revealed the most artifacts for Onyx 18 and the least artifacts for n-BCA, PHIL 25%, and PHIL LV. Squid caused more artifacts compared with PHIL, both for the low-viscosity and for the extra-low-viscosity versions (eg, quantitative analysis, Squid 18: mean ± SD, 30.3 ± 9.7 HU versus PHIL 25%: mean ± SD, 10.6 ± 0.8 HU; P < .001). Differences between the standard and low-density variants of Squid were observed only quantitatively for Squid 12. There were no statistical differences between the different concentrations of Squid and PHIL.

CONCLUSIONS

In this systematic in vitro analysis investigating the most commonly used liquid embolic agents, relevant differences in CT imaging artifacts could be demonstrated. Ethylene-vinyl alcohol-based liquid embolic agents induced more artifacts compared with liquid embolic agents that use iodine as a radiopaque component.

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.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00234-020-02619-1.

Automated Perfusion Calculations vs. Visual Scoring of Collaterals and CBV-ASPECTS : Has the Machine Surpassed the Eye?

Purpose

Use of automated perfusion software has gained importance for imaging of stroke patients for mechanical thrombectomy (MT). We aim to compare four perfusion software packages: 1) with respect to their association with 3‑month functional outcome after successful reperfusion with MT in comparison to visual Cerebral Blood Volume - Alberta Stroke Program Early CT Score (CBV-ASPECTS) and collateral scoring and 2) with respect to their agreement in estimation of core and penumbra volume.

Methods

This retrospective, multicenter cohort study (2015–2019) analyzed data from 8 centers. We included patients who were functionally independent before and underwent successful MT of the middle cerebral artery. Primary outcome measurements were the relationship of core and penumbra volume calculated by each software, qualitative assessment of collaterals and CBV-APECTS with 3‑month functional outcome and disability (modified Rankin scale >2). Quantitative differences between perfusion software measurements were also assessed.

Results

A total of 215 patients (57% women, median age 77 years) from 8 centers fulfilled the inclusion criteria. Multivariable analyses showed a significant association of RAPID core (common odds ratio, cOR 1.02; p = 0.015), CBV-ASPECTS (cOR 0.78; p = 0.007) and collaterals (cOR 0.78; p = 0.001) with 3‑month functional outcome (shift analysis), while RAPID core (OR 1.02; p = 0.018), CBV-ASPECTS (OR 0.77; p = 0.024), collaterals (OR 0.78; p = 0.007) and OLEA core (OR 1.02; p = 0.029) were significantly associated with 3‑month functional disability. Mean differences on core estimates between VEOcore and RAPID were 13.4 ml, between syngo.via and RAPID 30.0 ml and between OLEA and RAPID −3.2 ml.

Conclusion

Collateral scoring, CBV-ASPECTS and RAPID were independently associated with functional outcome at 90 days. Core and Penumbra estimates using automated software packages varied significantly and should therefore be used with caution.

Electronic supplementary material

The online version of this article (10.1007/s00062-020-00974-3) contains supplementary material, which is available to authorized users.

Treatment of Ruptured Blister-Like Aneurysms with the FRED Flow Diverter: A Multicenter Experience

BACKGROUND AND PURPOSE

Treatment of ruptured blister-like aneurysms is technically challenging. This study aimed at analyzing the safety and efficacy of the Flow-Redirection Endoluminal Device (FRED) in the treatment of ruptured blister-like aneurysms.

MATERIALS AND METHODS

In a retrospective multicenter study, all patients treated with the FRED due to a ruptured intracranial blister-like aneurysm between January 2013 and May 2019 were analyzed. The primary end points for clinical safety were mRS 0-2 at 6 months after treatment and the absence of major ipsilateral stroke or death. The primary end points for efficacy were the absence of rebleeding after treatment and complete angiographic occlusion according to the O'Kelly-Marotta classification at 6 months after treatment.

RESULTS

In total, 30 patients with 30 ruptured blister-like aneurysms were treated. Immediate complete aneurysm obliteration (O'Kelly-Marotta classification D) with the FRED was achieved in 10 patients (33%). Of the 26 patients with follow-up, complete obliteration was achieved in 21 patients (80%) after 6 months and in 24 patients (92%) in the final follow-up (median, 22 months). Twenty-three patients (77%) achieved mRS 0-2 at 6 months. Major stroke or death occurred in 17%. Two patients died due to pneumonia, and 2 patients died due to infarction following cerebral vasospasm. There was no case of rebleeding after FRED implantation. There was 1 case of delayed asymptomatic stent occlusion.

CONCLUSIONS

Treatment of ruptured blister-like aneurysms with the FRED is safe and effective.

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.

Patient-centredness in acute stroke care - a qualitative study from the perspectives of patients, relatives and staff

BACKGROUND AND PURPOSE

Although patient-centredness is considered a key component of high-quality neurological care, it is unclear to what extent it can or should be implemented during the acute phase. Using acute stroke as an example, the aim was to identify critical junctures for patient-centredness along the acute care pathway from the perspectives of patients, relatives and staff.

METHODS

A qualitative multi-method study was conducted including 27 non-participant observations and 37 semi-structured interviews with patients, relatives and staff. Junctures were defined as critical when mentioned (as problematic) in two or three information sources (i.e. observations, staff interviews, or patient and relative interviews), as potentially critical when mentioned in one, and as uncritical when not mentioned.

RESULTS

Post-procedure communication after thrombectomy, patients' stay at the stroke unit and decision-making around transfer, discharge and rehabilitation were identified as critical junctures for patient-centredness. Arrival at the emergency department and the (thrombectomy) treatment itself were identified as uncritical junctures, whilst history-taking and treatment preparation, the treatment decision and patients' stay at the intensive care unit were identified as potentially critical junctures.

CONCLUSIONS

In acute stroke care, patients, relatives and staff prioritize fast over patient-centred decision-making in the most time-critical phases, especially before and during treatment. This is reversed after the procedure, when difficulties arise implementing a patient-centred approach in clinical practice. To improve patient-centredness where it is most needed, clear guidelines and accessible resources are recommended. Future research should investigate whether insights from acute phases of stroke care are applicable to other neurological conditions as well.

Effect of treatment technique on radiation exposure in mechanical thrombectomy for acute ischaemic stroke: A matched-pair analysis

OBJECTIVE

This study aimed to compare radiation exposure (RE) in patients receiving mechanical thrombectomy (MT) for large-vessel occlusions in the anterior circulation using direct thrombo-aspiration (DT) versus stent-retriever thrombectomy under continuous distal aspiration (STA).

METHODS

This was a retrospective single-centre analysis of an Institutional Review Board-approved stroke database of a comprehensive stroke centre focusing on RE per dose area product, procedure time (PT) and fluoroscopy time (FT) in patients receiving MT. Patients who received MT with DT were matched with patients treated using STA according to occlusion location, mode of anaesthesia, manoeuvre count and sex.

RESULTS

Apart from patient age (DT: M = 74 years (standard deviation (SD)=13 years); STA: M = 79 years (SD = 11 years); p = 0.023), there was no difference in baseline patient characteristics (n = 68 per group). PT (DT: median = 26 minutes (interquartile range (IQR) = 21-38 minutes); STA: median = 49 minutes (IQR 37-77 minutes); p < 0.0001) and FT (DT: median = 12 minutes (IQR 7-18 minutes); STA: median = 26 minutes (IQR 14-43 minutes); p < 0.0001) were shorter in patients who received MT using DT. RE (DT: median = 62.6 Gy·cm² (IQR 41.7-89.4 Gy·cm²); STA: median = 89.8 Gy·cm² (IQR 53.7-131.7 Gy·cm²); p = 0.034) was significantly lower in patients who received MT using DT. This represents a relative increase of RE, FT and PT by 43.6%, 116.6% and 88.5%, respectively, in patients who received MT using STA.

CONCLUSION

MT using DT is associated with shorter FT and PT and lower RE compared to matched patients treated with STA.

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 value_1vs2, < 0.001; DAP₃, 130.2 (89.1–183.6); p value_2vs3, 0.044; DAP₄, 169.9 (128.4–224.1); p value_3vs4, 0.001; and DAP₅, 227.6 (146.3–294.6); p value_4vs5, 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 cm²for 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.

Time Metrics to Endovascular Thrombectomy in 3 Triage Concepts

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.

The Influence of Angioarchitectural Features on the Success of Endovascular Embolization of Cranial Dural Arteriovenous Fistulas with Onyx

BACKGROUND AND PURPOSE

Endovascular embolization can be an effective treatment for cranial dural arteriovenous fistulas. However, a considerable number of dural arteriovenous fistulas still cannot be treated sufficiently. The purpose of this study was to report our single-center experience of endovascular embolization of dural arteriovenous fistulas with Onyx, including the investigation of the influence of angioarchitectural features on the treatment success.

MATERIALS AND METHODS

Clinical data, angioarchitectural features, complications, treatment success (defined as complete symptom remission for low-grade dural arteriovenous fistulas and complete occlusion for high-grade dural arteriovenous fistulas), and occlusion rates were assessed. The influence of various angioarchitectural features (including location, pattern of venous drainage, and quantity and origin of feeding arteries) was investigated using multivariable backward logistic regression.

RESULTS

One hundred four patients with 110 dural arteriovenous fistulas were treated in 132 treatment procedures. Treatment success and complete occlusion rates were 81.8% and 90.9%, respectively. After a mean follow-up of 23.6 months, 95.5% of the patients showed complete symptom remission or symptom relief. The overall complication rate was 8.3% (4.5% asymptomatic, 2.3% transient, and 1.5% permanent complications). Logistic regression showed that ≥10 feeding arteries (P = .041) and involvement of the ascending pharyngeal artery (P = .039) significantly lowered the probability of treatment success. Treatment success tended to be lower for low-grade dural arteriovenous fistulas, Cognard type I dural arteriovenous fistulas, and dural arteriovenous fistulas with involvement of dural branches of the internal carotid artery, however without reaching statistical significance in the multivariable model.

CONCLUSIONS

The presence of multiple feeding arteries and involvement of the pharyngeal artery negatively influence the treatment success of endovascular embolization of cranial dural arteriovenous fistulas with Onyx.

Prediction of intracranial hemorrhages after mechanical thrombectomy of basilar artery occlusion

Background

Mechanical thrombectomy (MT) achieves high recanalization rates in basilar artery occlusion (BAO). A severe complication of MT in BAO is intracranial hemorrhage (ICH). Yet, knowledge of risk factors for ICH after MT in BAO is limited.

Objective

To evaluate clinical and procedural parameters of patients treated with MT owing to BAO to identify potential risk factors for ICH—in particular, symptomatic ICH (sICH), and assess their clinical relevance.

Methods

We conducted a retrospective analysis of 101 consecutive patients presenting with BAO, who were treated with MT in our centre. Important clinical and procedural parameters were analysed as possible predictors for any ICH and sICH according to the Heidelberg Bleeding Classification using univariate tests and multivariate logistic regressions.

Results

ICH occurred in 25 (24.8%) patients, with a total of 7 (6.9%) developing sICH. Treatment with glycoprotein IIb/IIIa (GPIIb/IIIa) inhibitors was independently associated with any ICH (OR=24.67, 95% CI 4.90 to 124.03) and sICH (OR=7.08, 95% CI 1.36 to 36.78). Also, a longer onset-to-recanalization time increased the risk of both any ICH (OR=1.17, 95% CI 1.07 to 1.31) and sICH (OR=1.22, 95% CI 1.08 to 1.42). Higher serum glucose levels were associated with a higher incidence of any ICH (OR=1.39, 95% CI 1.06 to 1.85) and a higher risk of a fatal outcome (OR=1.03, 95% CI 1.01 to 1.05).

Conclusion

Administration of GPIIb/IIIa inhibitor during the course of MT of BAO was identified as an important risk factor in the development of any ICH and sICH.

Clinical Outcome after Thrombectomy in Patients with Stroke with Premorbid Modified Rankin Scale Scores of 3 and 4: A Cohort Study with 136 Patients

BACKGROUND AND PURPOSE

We aimed to analyze the clinical outcome after mechanical thrombectomy in patients with premorbid mRS 3 and 4 because there are currently no data on this patient group.

MATERIALS AND METHODS

Between January 2009 and November 2017, all patients with premorbid mRS 3 or 4 undergoing mechanical thrombectomy due to anterior circulation stroke were selected. Good outcome was defined as a clinical recovery to the status before stroke onset (ie, equal premorbid mRS and mRS at 90 days). In addition, mortality at discharge and at 90 days was analyzed.

RESULTS

One hundred thirty-six patients were included, of whom 81.6% presented with premorbid mRS 3; and 18.4%, with premorbid mRS 4; 24.0% of patients with premorbid mRS 4 achieved clinical recovery compared with 20.7% of patients with premorbid mRS 3 (P = .788). However, the proportion of hospital mortality and mortality at 90 days was nonsignificant, but markedly higher in patients with premorbid mRS 4. Multivariate analysis identified low NIHSS scores (OR, 0.92; 95% CI, 0.85-0.99; P = .040), high ASPECTS (OR, 1.45; 95% CI, 1.02-2.16; P = .049), and TICI 2b-3 (OR, 7.11; 95% CI, 1.73-49.90; P = .017) as independent predictors of good outcome.

CONCLUSIONS

Good outcome in patients with premorbid mRS 3 and 4 is less frequent compared with premorbid mRS 0-2. Nevertheless, about 20% of the patients return to their premorbid mRS, which may justify endovascular treatment. The most important predictor of good outcome is successful recanalization.

Clinical results of a new concept of neurothrombectomy coverage at a remote hospital—“drive the doctor”

Background

Many tertiary care hospitals cannot provide a continuous thrombectomy service due to the lack of a neurointerventionalist.

Aims

In this study, we present procedural and clinical results of a new concept in which neuroradiologists of a university hospital provide neurointerventional stroke service to a remote hospital (“drive the doctor”).

Methods

All consecutive patients with acute ischemic stroke due to large vessel occlusion of the anterior circulation treated with mechanical thrombectomy after hours at a remote hospital (distance of about 100 km) between 2012 and 2016 were analyzed retrospectively. These patients were compared to a group of patients referred to the above mentioned university hospital for MT over a comparable distance (“drip and ship”).

Results

A total of 60 patients were treated by “drive the doctor” and 66 patients were treated by “drip and ship.” Time from onset to imaging was similar in both groups (77 vs. 70 min, P = 0.6847). However, time from imaging to groin puncture was significantly lower in the “drive the doctor” model (112 vs. 232 min, P < 0.0001). Nonetheless, recanalization rate and clinical outcome were similar in both cohorts.

Conclusions

“Drive the doctor” is a feasible concept of neurothrombectomy coverage at remote hospitals. The presented data suggest that “drive the doctor” is not inferior compared to established stroke concepts such as “drip and ship” regarding recanalization rate and outcome. However, larger and prospective studies are necessary to confirm this finding.

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.

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 T_max 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. T_max 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, T_max > 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

T_max at delays of >8 and 10 s is a good predictor for clinical outcome in MCA occlusions. In carotid T occlusion, however, T_max volumes do not correlate with outcome.

Correlation of Thrombectomy Maneuver Count with Recanalization Success and Clinical Outcome in Patients with Ischemic Stroke

BACKGROUND AND PURPOSE

In the treatment of acute thromboembolic stroke, the effectiveness and success of thrombus removal when using stent retrievers is variable. In this study, we analyzed the correlation of thrombectomy maneuver count with a good clinical outcome and recanalization success.

MATERIALS AND METHODS

One hundred and four patients with acute occlusion of the middle cerebral artery or the terminal internal carotid artery who were treated with thrombectomy were included in this retrospective study. A good clinical outcome was defined as a 90-day mRS of ≤2, and successful recanalization was defined as TICI 2b-3.

RESULTS

The maneuver count ranged between 1-10, with a median of 2. Multivariate logistic regression analyses identified an increasing number of thrombectomy maneuvers as an independent predictor of poor outcome (adjusted OR, 0.59; 95% CI, 0.38-0.87; P = .011) and unsuccessful recanalization (adjusted OR, 0.48; 95% CI, 0.32-0.66; P < .001). A good outcome was significantly more likely if finished within 2 maneuvers compared with 3 or 4 maneuvers, or even more than 4 maneuvers (P < .001).

CONCLUSIONS

An increasing maneuver count correlates strongly with a decreasing probability of both good outcome and recanalization. The probability of successful recanalization decreases below 50% if not achieved within 5 thrombectomy maneuvers. Patients who are recanalized within 2 maneuvers have the best chance of achieving a good clinical outcome.

Impact of thrombus length on recanalization and clinical outcome following mechanical thrombectomy in acute ischemic stroke

PURPOSE

The impact of thrombus length on recanalization in IV thrombolysis for acute intracranial artery occlusion has been well studied. Here we analyzed the influence of thrombus length on the number of thrombectomy maneuvers needed for recanalization, intraprocedural complications, recanalization success, and clinical outcome after mechanical thrombectomy.

METHODS

We retrospectively analyzed angiographic and clinical data from 72 consecutive patients with acute occlusion of the M1 segment of the middle cerebral artery who were treated with mechanical thrombectomy using stent retrievers. Successful recanalization was defined as a Thrombolysis in Cerebral Infarction score of 2b or 3. Good neurological outcome was defined as a modified Rankin Scale score of ≤2 at 90 days after stroke onset.

RESULTS

Mean thrombus length was 13.4±5.2 mm. Univariate binary logistic regression did not show an association of thrombus length with the probability of a good clinical outcome (OR 0.95, 95% CI 0.84 to 1.03, p=0.176) or successful recanalization (OR 0.92, 95% CI 0.81 to 1.05, p=0.225). There was no significant correlation between thrombus length and the number of thrombectomy maneuvers needed for recanalization (p=0.112). Furthermore, thrombus length was not correlated with the probability of intraprocedural complications (p=0.813), including embolization in a new territory (n=3).

CONCLUSIONS

In this study, thrombus length had no relevant impact on recanalization, neurological outcome, or intraprocedural complications following mechanical thrombectomy of middle cerebral artery occlusions. Therefore, mechanical thrombectomy with stent retrievers can be attempted with large clots.

Comparison of four different collateral scores in acute ischemic stroke by CT angiography

Purpose

Multiple scores have been described for the assessment of collateralization in acute ischemic stroke. Currently, there is no gold standard for collateral assessment by CT angiography (CTA). This study compared four frequently used collateral scores with regard to their correlation with early infarct core and mismatch ratio.

Methods

30 consecutive patients with acute occlusion of the M1 segment or terminal carotid artery were reviewed retrospectively. Collaterals were assessed using dynamic and also single-phase CTA according to grading systems by the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR), Alberta Stroke Program Early CT Score (ASPECTS) (on collaterals), Christoforidis et al and Miteff et al. The Christoforidis and ASITN/SIR scores, which were initially designed for conventional angiography, were adapted to be applicable to CTA. The scores were compared with respect to early infarct core and mismatch ratio in perfusion CT estimated by RAPID software using Spearman correlation.

Results

ASITN/SIR and ASPECTS collateral scores showed good correlation with early infarct core (rho=−0.696, p<0.001 and rho=−0.677, p<0.001) and mismatch ratio (rho=0.609, p<0.001 and rho=0.581, p<0.001). In contrast, the Christoforidis and Miteff scores correlated less well with infarct core (rho=0.245, p=0.191 and rho=−0.272, p=0.145, respectively) and mismatch ratio (rho=−0.329, p=0.075 and rho=0.279, p=0.135, respectively). ASPECTS and ASITN/SIR showed excellent cross-correlation (rho=0.901, p<0.001).

Conclusions

Compared with the Christoforidis and Miteff scores, the modified ASITN/SIR and ASPECTS collateral scores showed consistently higher correlation with the extent of early infarct core and mismatch volume. This is probably because these scores evaluate the extent and delay of vascular enhancement in the affected territory rather than the backflow of contrast medium to the occlusion.

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.