Modeling diffusion-weighted imaging lesion expansion between 2 and 24 h after endovascular thrombectomy in acute ischemic stroke

PURPOSE

Diffusion-weighted imaging (DWI) lesion expansion after endovascular thrombectomy (EVT) is not well characterized. We used serial diffusion-weighted magnetic resonance imaging (MRI) to measure lesion expansion between 2 and 24 h after EVT.

METHODS

In this single-center observational analysis of patients with acute ischemic stroke due to large vessel occlusion, DWI was performed post-EVT (< 2 h after closure) and 24-h later. DWI lesion expansion was evaluated using multivariate generalized linear mixed modeling with various clinical moderators.

RESULTS

We included 151 patients, of which 133 (88%) had DWI lesion expansion, defined as a positive change in lesion volume between 2 and 24 h. In an unadjusted analysis, median baseline DWI lesion volume immediately post-EVT was 15.0 mL (IQR: 6.6-36.8) and median DWI lesion volume 24 h post-EVT was 20.8 mL (IQR: 9.4-66.6), representing a median change of 6.1 mL (IQR: 1.5-17.7), or a 39% increase. There were no significant associations among univariable models of lesion expansion. Adjusted models of DWI lesion expansion demonstrated that relative lesion expansion (defined as final/initial DWI lesion volume) was consistent across eTICI scores (0-2a, 0.52%; 2b, 0.49%; 2c-3, 0.42%, p = 0.69). For every 1 mL increase in lesion volume, there was 2% odds of an increase in 90-day mRS (OR: 1.021, 95%CI [1.009, 1.034], p < 0.001).

CONCLUSION

We observed substantial lesion expansion post-EVT whereby relative lesion expansion was consistent across eTICI categories, and greater absolute lesion expansion was associated with worse clinical outcome. Our findings suggest that alternate endpoints for cerebroprotectant trials may be feasible.

Treatment practice of vasospasm during endovascular thrombectomy: an international survey

BACKGROUND AND AIM

The clinical importance and management of vasospasm as a complication during endovascular stroke treatment (EVT) has not been well studied. We sought to investigate current expert opinions in neurointervention and therapeutic strategies of iatrogenic vasospasm during EVT.

METHODS

We conducted an anonymous international online survey (4 April 2023 to 15 May 2023) addressing treatment standards of neurointerventionalists (NIs) practising EVT. Several illustrative cases of patients with vasospasm during EVT were shown. Two study groups were compared according to the NI's opinion regarding the potential influence of vasospasm on patient outcome after EVT using descriptive analysis.

RESULTS

In total, 534 NI from 56 countries responded, of whom 51.5% had performed >200 EVT. Vasospasm was considered a complication potentially influencing the patient's outcome by 52.6% (group 1) whereas 47.4% did not (group 2). Physicians in group 1 more often added vasodilators to their catheter flushes during EVT routinely (43.7% vs 33.9%, p=0.033) and more often treated severe large-vessel vasospasm with vasodilators (75.3% vs 55.9%; p<0.001), as well as extracranial vasospasm (61.4% vs 36.5%, p<0.001) and intracranial medium-vessel vasospasm (27.1% vs 11.2%, p<0.001), compared with group 2. In case of a large-vessel vasospasm and residual and amenable medium-vessel occlusion during EVT, the study groups showed different treatment strategies. Group 2 continued the EVT immediately more often, without initiating therapy to treat the vasospasm first (9.6% vs 21.1%, p<0.001).

CONCLUSION

There is disagreement among NIs about the clinical relevance of vasospasm during EVT and its management. There was a higher likelihood of use of preventive and active vasodilator treatment in the group that perceived vasospasm as a relevant complication as well as differing interventional strategies for continuing an EVT in the presence of a large-vessel vasospasm.

Metric based virtual simulation training for endovascular thrombectomy improves interventional neuroradiologists' simulator performance

OBJECTIVE

Metric based virtual reality simulation training may enhance the capability of interventional neuroradiologists (INR) to perform endovascular thrombectomy. As pilot for a national simulation study we examined the feasibility and utility of simulated endovascular thrombectomy procedures on a virtual reality (VR) simulator.

METHODS

Six INR and four residents participated in the thrombectomy skill training on a VR simulator (Mentice VIST 5G). Two different case-scenarios were defined as benchmark-cases, performed before and after VR simulator training. INR performing endovascular thrombectomy clinically were also asked to fill out a questionnaire analyzing their degree of expectation and general attitude towards VR simulator training.

RESULTS

All participants improved in mean total procedure time for both benchmark-cases. Experts showed significant improvements in handling errors (case 2), a reduction in contrast volume used (case 1 and 2), and fluoroscopy time (case 1 and 2). Novices showed a significant improvement in steps finished (case 2), a reduction in fluoroscopy time (case 1), and radiation used (case 1). Both, before and after having performed simulation training the participating INR had a positive attitude towards VR simulation training.

CONCLUSION

VR simulation training enhances the capability of INR to perform endovascular thrombectomy on the VR simulator. INR have generally a positive attitude towards VR simulation training. Whether the VR simulation training translates to enhanced clinical performance will be evaluated in the ongoing Norwegian national simulation study.

Intracranial hemorrhage in large vessel occlusion patients receiving endovascular thrombectomy with or without intravenous alteplase: a secondary analysis of the DIRECT-MT trial

BACKGROUND

Alteplase before thrombectomy for patients with large vessel occlusion stroke raises concerns regarding an increased risk of intracranial hemorrhage (ICH), but the details of this relationship are not well understood.

METHODS

This was a secondary analysis of the DIRECT-MT trial. ICH and its subtypes were independently reviewed and classified according to the Heidelberg Bleeding Classification. The effects of alteplase before thrombectomy on ICH and ICH subtypes occurrence were evaluated using logistic regression. Clinical and imaging characteristics that may modify these effects were exploratorily tested.

RESULTS

Among 591 patients, any ICH occurred in 254 (43.0%), including hemorrhagic infarction type 1 in 12 (2.1%), hemorrhagic infarction type 2 in 127 (21.7%), parenchymal hematoma type 1 in 34 (5.8%), parenchymal hematoma type 2 in 50 (8.6%), and other hemorrhage types (3a-3c) in 24 (4.1%). Similar ICH frequencies were observed with combined alteplase and thrombectomy versus thrombectomy only (134/292 (45.9%) vs 120/299 (40.1%); OR 1.27, 95% CI 0.91 to 1.75, P=0.16), but patients treated with alteplase had a higher parenchymal hematoma rate (51/287 (17.8%) vs 33/297 (11.1%); OR 1.75, 95% CI 1.08 to 2.85, P=0.024). In the adjusted model, difference in parenchymal hematoma occurrence between groups remained significant (adjusted OR 1.71, 95% CI 1.00 to 2.92, P=0.049). Patients with history of diabetes (Pinteraction=0.048), hypertension (Pinteraction=0.02), antiplatelet therapy (Pinteraction=0.02), anticoagulation therapy (Pinteraction=0.04), and statin administration (Pinteraction=0.02) harbored a higher ICH rate when they received combination therapy.

CONCLUSIONS

Our data showed that in the DIRECT-MT trial, alteplase did not increase overall ICH for large vessel occlusion patients treated with thrombectomy, but it increased the parenchymal hematoma rate.

Virtual reality simulation training in stroke thrombectomy centers with limited patient volume-Simulator performance and patient outcome

BACKGROUND

Virtual reality simulation training may improve the technical skills of interventional radiologists when establishing endovascular thrombectomy at limited-volume stroke centers. The aim of this study was to investigate whether the technical thrombectomy performance of interventional radiologists improved after a defined virtual reality simulator training period. As part of the quality surveillance of clinical practice, we also assessed patient outcomes and thrombectomy quality indicators at the participating centers.

METHODS

Interventional radiologists and radiology residents from three thrombectomy-capable stroke centers participated in a five months thrombectomy skill-training curriculum on a virtual reality simulator. The simulator automatically registered procedure time, the number of predefined steps that were correctly executed, handling errors, contrast volume, fluoroscopy time, and radiation dose exposure. The design was a before-after study. Two simulated thrombectomy cases were used as pretest and posttest cases, while seven other cases were used for training. Utilizing the Norwegian Stroke Register, we investigated clinical results in thrombectomy during the study period.

RESULTS

Nineteen interventional radiologists and radiology residents participated in the study. The improvement between pretest and posttest cases was statistically significant for all outcome measures in both simulated cases, except for the contrast volume used in one case. Clinical patient outcomes in all three centers were well within the recommendations from multi-society consensus guidelines.

CONCLUSION

Performance on the virtual reality simulator improved after training. Virtual reality simulation may improve the learning curve for interventional radiologists in limited-volume thrombectomy centers. No correlation alleged, the clinical data indicates that the centers studied performed thrombectomy in accordance with guideline-recommended standards.

The Vessel Has Been Recanalized: Now What?

When treating acute ischemic stroke patients in our daily clinical practice, we strive to achieve recanalization of the occluded blood vessel as fast as possible using pharmacological thrombolysis and mechanical clot removal. However, successful recanalization does not equal successful reperfusion of the ischemic tissue due to mechanisms such as microvascular obstruction. Even if successful reperfusion is achieved, numerous other post-recanalization tissue damage mechanisms may impair patient outcomes, namely blood-brain barrier breakdown, reperfusion injury and excitotoxicity, late secondary changes, and post-infarction local and global brain atrophy. Several cerebroprotectants are currently evaluated as adjunctive treatments to pharmacological thrombolysis and mechanical clot removal, many of which interfere with post-recanalization tissue damage pathways. However, our current lack of knowledge about the prevalence and importance of the various post-recanalization tissue damage mechanisms makes it difficult to reliably identify the most promising cerebroprotectants and to design appropriate clinical trials to evaluate them. Serial human MRI studies with complementary animal studies in higher order primates could provide answers to these critical questions and should be first conducted to allow for adequate cerebroprotection trial design, which could accelerate the translation of cerebroprotective agents from bench to bedside to further improve patient outcomes.

Sex and Gender Differences in Stroke and Their Practical Implications in Acute Care

There are several controversies regarding the role of sex and gender in the pathophysiology and management of acute stroke. Assessing the role of sex, i.e., biological/pathophysiological factors, and gender, i.e., sociocultural factors, in isolation is often not possible since they are closely intertwined with each other. To complicate matters even more, the functional baseline status of women and men at the time of their first stroke is substantially different, whereby women have, on average, a poorer reported/ascertained baseline function compared to men. These differences in baseline variables account for a large part of the differences in post-stroke outcomes between women and men. Adjusting for these baseline differences is difficult, and in many cases, residual confounding cannot be excluded. Despite these obstacles, a better understanding of how patient sex and gender differences influence acute stroke and stroke care pathways is crucial to avoid biases and allow us to provide the best possible care for all acute stroke patients. Disregarding patient sex and gender on one hand and ignoring potential confounding factors in sex- and gender-stratified analyses on the other hand, may cause researchers to come to erroneous conclusions and physicians to provide suboptimal care. This review outlines sex- and gender-related factors in key aspects of acute stroke, including acute stroke epidemiology, diagnosis, access to care, treatment outcomes, and post-acute care. We also attempt to outline knowledge gaps, which deserve to be studied in further detail, and practical implications for physicians treating acute stroke patients in their daily practice.

Effect of Admission Hyperglycemia on Safety and Efficacy of Intravenous Alteplase Before Thrombectomy in Ischemic Stroke: Post-hoc Analysis of the DIRECT-MT trial

Hyperglycemia is associated with decreased recanalization probability and increased risk of hemorrhagic complications for stroke patients treated with intravenous alteplase. However, whether hyperglycemia modifies alteplase treatment effect on clinical outcome in patients with large vessel occlusion stroke undergoing endovascular thrombectomy is uncertain. We conducted this study to determine a possible interaction effect between admission hyperglycemia and intravenous alteplase prior to thrombectomy in patients with large vessel occlusion stroke. In this post-hoc analysis of a randomized trial (DIRECT-MT) comparing intravenous alteplase before endovascular treatment vs. endovascular treatment only, 649 with available baseline glucose measurements were included. The treatment-by-admission hyperglycemia (defined as plasma glucose levels ≥ 7.8 mmol/L [140 mg/dL]) interaction was assessed using logistic regression models. As a result, among 649 patients included, 224 (34.5%) were hyperglycemic at admission. There was evidence of alteplase treatment effect modification by hyperglycemia (Pinteraction = 0.025). In patients without hyperglycemia, combination therapy was associated with better outcomes compared to mechanical thrombectomy alone (adjusted common odd ratio [acOR] 1.46, 95% CI [1.04-2.07]), but not in hyperglycemic patients (acOR 0.74, 95% CI [0.46-1.20]). Combination therapy led to an absolute increase of 6% excellent outcome (mRS 0-1) in non-hyperglycemic patients (aOR 1.71, 95% CI [1.05-2.79]), but resulted in a 12.3% absolute decrease (aOR 0.42 [95% CI, 0.19-0.95] in hyperglycemic patients (Pinteraction = 0.003). In conclusion, for large vessel occlusion patients directly presenting to a thrombectomy-capable hospital, hyperglycemia modified combination treatment effect on clinical outcome. Combination therapy was beneficial in patients without hyperglycemia, while thrombectomy alone may be preferred in hyperglycemic patients. Further studies are needed to confirm this result.Trial Registration Information: clinicaltrials.gov Identifier: NCT03469206.

CT Hyperdense Artery Sign and the Effect of Alteplase in Endovascular Thrombectomy after Acute Stroke

Background Recent evidence suggests that presence of an intracranial arterial thrombus with a hyperdense artery sign (HAS) at noncontrast CT (NCCT) is associated with better response to intravenous alteplase. Patients with HAS may benefit more from combined intravenous alteplase and endovascular treatment (EVT). Purpose To investigate whether HAS at NCCT modifies the treatment effect of adding intravenous alteplase on clinical outcome in patients with acute large-vessel occlusion undergoing EVT. Materials and Methods This study is a secondary analysis of a prospective randomized trial (Direct Intra-arterial thrombectomy in order to Revascularize AIS patients with large-vessel occlusion Efficiently in Chinese Tertiary hospitals: A Multicenter randomized clinical Trial [DIRECT-MT]), which compared adding alteplase to EVT versus EVT alone in participants with acute large-vessel occlusion between February 2018 and July 2019. Participants with catheter angiograms and adequate NCCT for HAS evaluation were included. HAS was determined visually by two independent investigators at baseline NCCT. Treatment effect of intravenous alteplase administration according to presence of HAS on the primary clinical outcome (modified Rankin Scale [mRS] score at 90 days) and secondary and safety outcomes were assessed using adjusted multivariable regression models. Results Among 633 included participants (356 men [56%]; median age, 69 years), HAS was observed in 283 participants (45%): 142 of 313 participants (45%) in the EVT-only group and 141 of 320 participants (44%) in the group with added intravenous alteplase. Treatment-by-HAS interaction was observed for the primary outcome (P < .001), whereby a shift in favor of better outcomes with added intravenous alteplase occurred in participants with HAS (adjusted odds ratio [OR]: 1.82; 95% CI: 1.18, 2.79), while an adverse effect was seen in participants without HAS (adjusted OR: 0.62; 95% CI: 0.42, 0.91). This also held true for three secondary outcomes (excellent outcome [mRS score of 0-1 at 90 days], P = .005; good outcome [mRS score of 0-2 at 90 days], P = .008; final successful reperfusion, P = .04) in the adjusted models. Conclusion After acute ischemic stroke, presence of hyperdense artery sign (HAS) at baseline noncontrast CT indicated better outcomes when alteplase was added to endovascular treatment, but adding alteplase to endovascular treatment resulted in worse outcomes in participants without HAS. Clinical trial registration no. NCT03469206 © RSNA, 2022 Online supplemental material is available for this article.

Benefit of successful reperfusion achieved by endovascular thrombectomy for patients with ischemic stroke and moderate pre-stroke disability (mRS 3): results from the MR CLEAN Registry

BACKGROUND

Pre-stroke dependent patients (modified Rankin Scale score (mRS) ≥3) were excluded from most trials on endovascular treatment (EVT) for acute ischemic stroke (AIS) in the anterior circulation. Therefore, little evidence exists for EVT in those patients. We aimed to investigate the safety and benefit of EVT in pre-stroke patients with mRS score 3.

METHODS

We used data from the Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic stroke in the Netherlands (MR CLEAN) Registry. All patients treated with EVT for anterior circulation AIS with pre-stroke mRS 3 were included. We assessed causes for dependence and compared patients with successful reperfusion (defined as expanded Thrombolysis in Cerebral Ischemia scale (eTICI) 2b-3) to patients without successful reperfusion. We used regression analyses with pre-specified adjustments. Our primary outcome was 90-day mRS 0-3 (functional improvement or return to baseline).

RESULTS

A total of 192 patients were included, of whom 82 (43%) had eTICI <2b and 108 (56%) eTICI ≥2b. The median age was 80 years (IQR 73-87). Fifty-one of the 192 patients (27%) suffered from previous stroke and 36/192 (19%) had cardiopulmonary disease. Patients with eTICI ≥2b more often returned to their baseline functional state or improved (n=26 (26%) vs n=15 (19%); adjusted odds ratio (aOR) 2.91 (95% CI 1.08 to 7.82)) and had lower mortality rates (n=49 (49%) vs n=50 (64%); aOR 0.42 (95% CI 0.19 to 0.93)) compared with patients with eTICI <2b.

CONCLUSIONS

Although patients with AIS with pre-stroke mRS 3 comprise a heterogenous group of disability causes, we observed improved outcomes when patients achieved successful reperfusion after EVT.

Thrombectomy With and Without Computed Tomography Perfusion Imaging in the Early Time Window: A Pooled Analysis of Patient-Level Data

BACKGROUND

The optimal imaging paradigm for endovascular thrombectomy (EVT) patient selection in early time window (0-6 hours) treated acute ischemic stroke patients remains uncertain. We aimed to compare post-EVT outcomes between patients who underwent prerandomization basic (noncontrast computed tomography [CT], CT angiography only) versus additional advanced imaging (computed tomography perfusion [CTP] imaging) and to determine the association of performance of prerandomization CTP imaging with clinical outcomes.

METHODS

The HERMES collaboration (Highly Effective Reperfusion Evaluated in Multiple Endovascular Stroke Trials) pooled patient-level data from randomized controlled trials comparing EVT with usual care for acute ischemic stroke due to anterior circulation large vessel occlusion. Good functional outcome, defined as modified Rankin Scale score 0 to 2 at 90 days, was compared between randomized patients with and without CTP baseline imaging. Univariable and multivariable binary logistic regression analysis was performed to determine the association of baseline CTP imaging and good functional outcome.

RESULTS

We analyzed 1348 patients 610 (45.3%) of whom underwent CTP prerandomization. The benefit of EVT compared with best medical management was maintained irrespective of the baseline imaging paradigm (90-day modified Rankin Scale score 0-2 in EVT versus control patients: with CTP: 46.0% (137/298) versus 28.9% (88/305), without CTP: 44.1% (162/367) versus 27.3% (100/366). Performance of CTP baseline imaging compared with baseline noncontrast CT and CT angiography only yielded similar rates of good outcome (odds ratio, 1.05 [95% CI, 0.82-1.33], adjusted odds ratio, 1.04, [95% CI, 0.80-1.35]).

CONCLUSIONS

Rates of good functional outcome were similar among patients in whom CTP was or was not performed, and EVT treatment effect in the 0- to 6-hour time window was similar in patients with and without baseline CTP imaging.

Acute ischaemic stroke associated with SARS-CoV-2 infection in North America

BACKGROUND

To analyse the clinical characteristics of COVID-19 with acute ischaemic stroke (AIS) and identify factors predicting functional outcome.

METHODS

Multicentre retrospective cohort study of COVID-19 patients with AIS who presented to 30 stroke centres in the USA and Canada between 14 March and 30 August 2020. The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) of 5 or 6 at discharge. Secondary endpoints include favourable outcome (mRS ≤2) and mortality at discharge, ordinal mRS (shift analysis), symptomatic intracranial haemorrhage (sICH) and occurrence of in-hospital complications.

RESULTS

A total of 216 COVID-19 patients with AIS were included. 68.1% (147/216) were older than 60 years, while 31.9% (69/216) were younger. Median [IQR] National Institutes of Health Stroke Scale (NIHSS) at presentation was 12.5 (15.8), and 44.2% (87/197) presented with large vessel occlusion (LVO). Approximately 51.3% (98/191) of the patients had poor outcomes with an observed mortality rate of 39.1% (81/207). Age >60 years (aOR: 5.11, 95% CI 2.08 to 12.56, p<0.001), diabetes mellitus (aOR: 2.66, 95% CI 1.16 to 6.09, p=0.021), higher NIHSS at admission (aOR: 1.08, 95% CI 1.02 to 1.14, p=0.006), LVO (aOR: 2.45, 95% CI 1.04 to 5.78, p=0.042), and higher NLR level (aOR: 1.06, 95% CI 1.01 to 1.11, p=0.028) were significantly associated with poor functional outcome.

CONCLUSION

There is relationship between COVID-19-associated AIS and severe disability or death. We identified several factors which predict worse outcomes, and these outcomes were more frequent compared to global averages. We found that elevated neutrophil-to-lymphocyte ratio, rather than D-Dimer, predicted both morbidity and mortality.

Association of Intravenous Alteplase, Early Reperfusion, and Clinical Outcome in Patients With Large Vessel Occlusion Stroke: Post Hoc Analysis of the Randomized DIRECT-MT Trial

BACKGROUND

The added value of intravenous alteplase in reperfusing ischemic brain tissue in patients undergoing endovascular treatment and directly presented to an endovascular treatment-capable hospital is uncertain. We conducted this post hoc analysis of a randomized trial (DIRECT-MT [Direct Intraarterial Thrombectomy in Order to Revascularize Acute Ischemic Stroke Patients With Large Vessel Occlusion Efficiently in Chinese Tertiary Hospitals: A Multicenter Randomized Clinical Trial]) to explore the association of intravenous alteplase, early (preendovascular treatment) reperfusion, and clinical outcome and to determine factors which may modify alteplase treatment effect on early reperfusion.

METHODS

In this post hoc analysis of the DIRECT-MT randomized trial comparing intravenous alteplase before endovascular treatment versus endovascular treatment only, 623 of 656 randomized patients, with adequate angiographic evaluation for early reperfusion assessment, were included. The association of intravenous alteplase and early reperfusion (defined as expanded Thrombolysis in Cerebral Infarction score ≥2a on angiogram) was assessed using unadjusted comparisons and multivariable logistic regression.

RESULTS

Among 623 patients included (317 received intravenous alteplase and 306 did not), early reperfusion occurred in 91 (15%) patients and was associated with better functional outcome (modified Rankin Scale score, 0-2 of 49/91 [54%] versus 178/531 [34%]; adjusted odds ratio, 1.92 [95% CI, 1.15-3.21]; P<0.001). Intravenous alteplase was independently associated with early reperfusion (59/317 [19%] versus 32/306 [10%]; adjusted odds ratio, 2.06 [95% CI, 1.27-3.33]; P=0.003), and the alteplase effect was modified by time from randomization to groin puncture (dichotomized by median, ≤33 minutes; adjusted odds ratio, 1.06 [95% CI, 0.53-2.10] versus >33 minutes; adjusted odds ratio, 4.07 [95% CI, 1.86-8.86]; P_interaction=0.012).

CONCLUSIONS

For patients with large vessel occlusion directly presenting to an endovascular treatment-capable hospital, intravenous alteplase increases early reperfusion when endovascular treatment gets delayed more than approximately half an hour. Thus, intravenous alteplase should be considered if endovascular treatment delays are anticipated by the treating medical team. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03469206.

The Challenge of Designing Stroke Trials That Change Practice: MCID vs. Sample Size and Pragmatism

Randomized controlled trials (RCT) are the basis for evidence-based acute stroke care. For an RCT to change practice, its results have to be statistically significant and clinically meaningful. While methods to assess statistical significance are standardized and widely agreed upon, there is no clear consensus on how to assess clinical significance. Researchers often refer to the minimal clinically important difference (MCID) when describing the smallest change in outcomes that is considered meaningful to patients and leads to a change in patient management. It is widely accepted that a treatment should only be adopted when its effect on outcome is equal to or larger than the MCID. There are however situations in which it is reasonable to decide against adopting a treatment, even when its beneficial effect matches or exceeds the MCID, for example when it is resource- intensive and associated with high costs. Furthermore, while the MCID represents an important concept in this regard, defining it for an individual trial is difficult as it is highly context specific. In the following, we use hypothetical stroke trial examples to review the challenges related to MCID, sample size and pragmatic considerations that researchers face in acute stroke trials, and propose a framework for designing meaningful stroke trials that have the potential to change clinical practice.

Endovascular treatment for cerebral venous thrombosis: current status, challenges, and opportunities

Cerebral venous thrombosis (CVT) mostly affects young people. So far, endovascular treatment (EVT) has not been shown to be beneficial in CVT, partially because venous EVT tools are not yet fully optimized, and therefore EVT is only used as a rescue treatment in rare cases. Identifying a subgroup of CVT patients that could benefit from EVT is challenging, given the milder course of disease compared with acute ischemic stroke, the paucity of data on prognostic factors (both in the clinical and imaging domain), and the lack of consensus on what constitutes 'technical success' in CVT EVT. In this review, we discuss the major obstacles that are encountered when trying to identify CVT patients that may benefit from EVT, and propose a roadmap that could help to overcome these challenges in the near future.

Time-Based Decision Making for Reperfusion in Acute Ischemic Stroke

Decision making in the extended time windows for acute ischemic stroke can be a complex and time-consuming process. The process of making the clinical decision to treat has been compounded by the availability of different imaging modalities. In the setting of acute ischemic stroke, time is of the essence and chances of a good outcome diminish by each passing minute. Navigating the plethora of advanced imaging modalities means that treatment in some cases can be inefficaciously delayed. Time delays and individually based non-programmed decision making can prove challenging for clinicians. Visual aids can assist such decision making aimed at simplifying the use of advanced imaging. Flow charts are one such visual tool that can expedite treatment in this setting. A systematic review of existing literature around imaging modalities based on site of occlusion and time from onset can be used to aid decision making; a more program-based thought process. The use of an acute reperfusion flow chart helping navigate the myriad of imaging modalities can aid the effective treatment of patients.

Influence of recent direct-to-EVT trials on practical decision-making for the treatment of acute ischemic stroke patients

BACKGROUND

Current guidelines recommend that eligible acute ischemic stroke (AIS) patients receive intravenous alteplase (IVT) prior to endovascular treatment (EVT). Six randomized controlled trials recently sought to determine the risks of administering IVT prior to EVT, five of which have been published/presented. It is unclear whether and how the results of these trials will change guidelines. With the DEBATE survey, we assessed the influence of the recent trials on physicians' IVT treatment strategies in the setting of EVT for large vessel occlusion (LVO) stroke.

METHODS

Participants were provided with 15 direct-to-mothership case-scenarios of LVO stroke patients and asked whether they would treat with IVT  +  EVT or EVT alone, a) before publication/presentation of the direct-to-EVT trials, and b) now (knowing the trial results). Logistic regression clustered by respondent was performed to assess factors influencing the decision to adopt an EVT-alone paradigm after publication/presentation of the trial results.

RESULTS

289 participants from 37 countries provided 4335 responses, of which 13.5% (584/4335) changed from an IVT  +  EVT strategy to EVT alone after knowing the trial results. Very few switched from EVT alone to IVT  +  EVT (8/4335, 0.18%). Scenarios involving a long thrombus (RR 1.88, 95%CI:1.56-2.26), cerebral micro-hemorrhages (RR 1.78, 95%CI:1.43-2.23), and an expected short time to recanalization (RR 1.46 95%CI:1.19-1.78) had the highest chance of participants switching to an EVT-only strategy.

CONCLUSION

In light of the recent direct-to-EVT trials, a sizeable proportion of stroke physicians appears to be rethinking IVT treatment strategies of EVT-eligible mothership patients with AIS due to LVO in specific situations.

State of the Art Stroke Imaging: A Current Perspective

Acute stroke is a widespread, debilitating disease. Fortunately, it also has one of the most effective therapeutic options available in medicine, endovascular treatment. Imaging plays a major role in the diagnosis of stroke and aids in appropriate therapy selection. Given the rapid accumulation of evidence for patient subgroups and concurrent broadening of therapeutic options and indications, it is important to recognize the benefits of certain imaging technologies for specific situations. An effective imaging protocol should: 1) be fast, 2) easily implementable, 3) produce reliable results, 4) have few contraindications, and 5) be safe, all with the goal of providing the patient the best chance of achieving a favorable outcome. In the following, we provide a review of the currently available imaging technologies, their advantages and disadvantages, as well as an overview of the future of stroke imaging. Finally, we offer a perspective.

Willingness to randomize primary medium vessel occlusions for endovascular treatment

BACKGROUND AND PURPOSE

Patients with acute ischemic stroke due to medium vessel occlusion (MeVO) make up a substantial part of the acute stroke population, though guidelines currently do not recommend endovascular treatment (EVT) for them. A growing body of evidence suggests that EVT is effective in MeVOs, including observational data but no randomized studies. We aimed to explore willingness of physicians worldwide to randomize MeVO stroke patients into a hypothetical trial comparing EVT in addition to best medical management versus best medical management only.

METHODS

In an international cross-sectional survey among stroke physicians, participants were presented with 4 cases of primary MeVOs (6 scenarios each). Each subsequent scenario changed one key patient characteristic compared to the previous one, and asked survey participants whether they would be willing to randomize the described patient. Overall, physician- and scenario-specific decision rates were calculated. Multivariable logistic regression with clustering by respondent was performed to assess factors influencing the decision to randomize.

RESULTS

Overall, 366 participants (56 women) from 44 countries provided 8784 answers to 24 MeVO case scenarios. The majority of responses (78.3%) were in favor of randomizing. Most physicians were willing to accept patients transferred for EVT from a primary center (82%) and the majority of these (76.5%) were willing to randomize these patients after transfer. Patient age > 65 years, A3 occlusion, small core volume, and patient intravenous alteplase eligibility significantly influenced the physician's decision to randomize (adjOR 1.24, 95%CI 1.13-1.36; adjOR 1.17, 95%CI 1.01-1.34; adjOR 0.98, 95%CI 0.97-0.99 and adjOR 1.38, 95%CI 1.21-1.57, respectively).

CONCLUSIONS

Most physicians in this survey were willing to randomize acute MeVO stroke patients irrespective of patient characteristics into a trial comparing EVT in addition to best medical management versus best medical management only, suggesting there is clinical equipoise.

Infarct Growth despite Successful Endovascular Reperfusion in Acute Ischemic Stroke: A Meta-analysis

BACKGROUND

Infarct volume inversely correlates with good recovery in stroke. The magnitude and predictors of infarct growth despite successful reperfusion via endovascular treatment are not known.

PURPOSE

We aimed to summarize the extent of infarct growth in patients with acute stroke who achieved successful reperfusion (TICI 2b-3) after endovascular treatment.

DATA SOURCES

We performed a systematic review and meta-analysis by searching MEDLINE and Google Scholar for articles published up to October 31, 2020.

STUDY SELECTION

Studies of >10 patients reporting baseline and post-endovascular treatment infarct volumes on MR imaging were included. Only patients with TICI 2b-3 were included. We calculated infarct growth at a study level as the difference between baseline and follow-up MR imaging infarct volumes.

DATA ANALYSIS

Our search yielded 345 studies, and we included 10 studies reporting on 973 patients having undergone endovascular treatment who achieved successful reperfusion.

DATA SYNTHESIS

The mean baseline infarct volume was 19.5 mL, while the mean final infarct volume was 37.5 mL. A TICI 2b reperfusion grade was achieved in 24% of patients, and TICI 2c or 3 in 76%. The pooled mean infarct growth was 14.8 mL (95% CI, 7.9-21.7 mL). Meta-regression showed higher infarct growth in studies that reported higher baseline infarct volumes, higher rates of incomplete reperfusion (modified TICI 2b), and longer onset-to-reperfusion times.

LIMITATIONS

Significant heterogeneity among studies was noted and might be driven by the difference in infarct growth between early- and late-treatment studies.

CONCLUSIONS

These results suggest considerable infarct growth despite successful endovascular treatment reperfusion and call for a faster workflow and the need for specific therapies to limit infarct growth.

Nonstenotic Carotid Plaques in Ischemic Stroke: Analysis of the STRATIS Registry

BACKGROUND AND PURPOSE

Few studies assess nonstenotic carotid plaques on CTA, and the causative role of these plaques in stroke is not entirely clear. We used CTA to determine the prevalence of nonstenotic carotid plaques (<50%), plaque features, and their association with ipsilateral strokes in patients with cardioembolic and cryptogenic strokes.

MATERIALS AND METHODS

Data were from the Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) registry, a prospective, nonrandomized registry of patients undergoing thrombectomy with the Solitaire device. The prevalence of nonstenotic carotid plaques ipsilateral and contralateral to the stroke was compared in patients with cryptogenic and cardioembolic strokes. Plaque features were further compared within both subgroups between patients with and without ipsilateral stroke. Adjusted associations among nonstenotic carotid plaque, plaque characteristics, and ipsilateral stroke in both subgroups were determined with logistic regression.

RESULTS

Of the 946 patients in the data base, 226 patients with cardioembolic stroke (median age, 72 years) and 141 patients with cryptogenic stroke (median age, 69 years) were included in the analysis. The prevalence of nonstenotic carotid plaque in the cardioembolic and cryptogenic subgroups was 33/226 (14.6%) and 32/141 (22.7%), respectively. Bilateral nonstenotic carotid plaques were seen in 10/226 (4.4%) patients with cardioembolic and 13/141 (9.2%) with cryptogenic strokes. Nonstenotic carotid plaques were significantly associated with ipsilateral strokes in the cardioembolic stroke (adjusted OR = 1.91; 95% CI, 1.15-3.18) and the cryptogenic stroke (adjusted OR = 1.69; 95% CI, 1.05-2.73) groups. Plaque irregularity, hypodensity, and per-millimeter increase in plaque thickness were significantly associated with ipsilateral stroke in the cryptogenic subgroup.

CONCLUSIONS

Nonstenotic carotid plaques were significantly associated with ipsilateral stroke in cardioembolic and cryptogenic stroke groups, and there was an association of plaque irregularity and hypodense plaque with ipsilateral stroke in the cryptogenic group, suggesting these plaques could be a potential cause of stroke in these patient subgroups.

Age and Acute Ischemic Stroke Outcome in North American Patients With COVID-19

Background

Acute ischemic stroke (AIS) in the context of COVID‐19 has received considerable attention for its propensity to affect patients of all ages. We aimed to evaluate the effect of age on functional outcome and mortality following an acute ischemic event.

Methods and Results

A prospectively maintained database from comprehensive stroke centers in Canada and the United States was analyzed for patients with AIS from March 14 to September 30, 2020 who tested positive for SARS‐CoV‐2. The primary outcome was Modified Rankin Scale score at discharge, and the secondary outcome was mortality. Baseline characteristics, laboratory values, imaging, and thrombectomy workflow process times were assessed. Among all 126 patients with COVID‐19 who were diagnosed with AIS, the median age was 63 years (range, 27–94). There were 35 (27.8%) patients with AIS in the aged ≤55 years group, 47 (37.3%) in the aged 56 to 70 group, and 44 (34.9%) in the aged >70 group. Intravenous tissue plasminogen activator and thrombectomy rates were comparable across these groups, (P=0.331 and 0.212, respectively). There was a significantly lower rate of mortality between each group favoring younger age (21.9% versus 45.0% versus 48.8%, P=0.047). After multivariable adjustment for possible confounders, a 1‐year increase in age was significantly associated with fewer instances of a favorable outcome of Modified Rankin Scale 0 to 2 (odds ratio [OR], 0.95; 95 CI%, 0.90–0.99; P=0.048) and higher mortality (OR, 1.06; 95 CI%, 1.02–1.10; P=0.007).

Conclusions

AIS in the context of COVID‐19 affects young patients at much greater rates than pre‐pandemic controls. Nevertheless, instances of poor functional outcome and mortality are closely tied to increasing age.

Influence of intravenous alteplase on endovascular treatment decision-making in acute ischemic stroke due to primary medium-vessel occlusion: a case-based survey study

Background

Intravenous alteplase is currently the only evidence-based treatment for medium-vessel occlusion stroke (MeVO; M2/3, A2/3, and P2/3 vessel segment occlusions), but due to its limited efficacy, endovascular treatment (EVT) is increasingly performed in these patients. In this case-based survey study, we examined the influence of intravenous alteplase treatment on physicians’ decision-making for EVT in primary MeVO stroke.

Methods

In an international web-based survey among physicians involved in acute stroke care, participants provided their EVT decision for six quasi-identical fictional MeVO case scenarios (three with and without intravenous alteplase administered). Each scenario showed radiological images and clinical information in the form of a short case vignette. We compared EVT decisions (“immediate EVT”, “no EVT”, or “wait for alteplase effect” [in case scenarios with alteplase treatment only]) for case scenarios with and without alteplase treatment. Clustered multivariable logistic regression was performed to assess the effect of alteplase on treatment decision.

Results

The survey was completed by 366 physicians from 44 countries, resulting in 2196 responses included in this study. In alteplase-treated cases, 641/1098 (58.4%) responses favored immediate EVT, (279/1098 [25.4%]) favored no EVT and 178/1098 (16.2%) opted to wait for alteplase effect. In non-alteplase-treated case scenarios, 846/1098 (78.7%) were in favor of and 252/1098 (21.3%) against EVT. Intravenous alteplase was associated with a lower chance of a decision in favor of immediate EVT (adjusted OR 0.38 [95%CI 0.31 to 0.46]).

Conclusions

Intravenous alteplase is an important factor in EVT decision-making for MeVO stroke. However, even in alteplase-treated patients, more than half of the physicians decided to proceed with EVT without waiting for alteplase effect.

Management and outcome of patients with acute ischemic stroke and tandem carotid occlusion in the ESCAPE-NA1 trial

BACKGROUND

The optimal treatment and prognosis for stroke patients with tandem cervical carotid occlusion are unclear. We analyzed outcomes and treatment strategies of tandem occlusion patients in the ESCAPE-NA1 trial.

METHODS

ESCAPE-NA1 was a multicenter international randomized trial of nerinetide versus placebo in 1105 patients with acute ischemic stroke who underwent endovascular treatment. We defined tandem occlusions as complete occlusion of the cervical internal carotid artery (ICA) on catheter angiography, in addition to a proximal ipsilateral intracranial large vessel occlusion. Baseline characteristics and outcome parameters were compared between patients with tandem occlusions versus those without, and between patients with tandem occlusion who underwent ICA stenting versus those who did not. The influence of tandem occlusions on functional outcome was analyzed using multivariable regression modeling.

RESULTS

Among 115/1105 patients (10.4%) with tandem occlusions, 62 (53.9%) received stenting for the cervical ICA occlusion. Of these, 46 (74.2%) were stented after and 16 (25.8%) before the intracranial thrombectomy. A modified Rankin Score (mRS) of 0-2 at 90 days was achieved in 82/115 patients (71.3%) with tandem occlusions compared with 579/981 (59.5%) patients without tandem occlusions. Tandem occlusion did not impact functional outcome in the adjusted analysis (OR 1.5, 95% CI 0.95 to 2.4). Among the subgroup of patients with tandem occlusion, cervical carotid stenting was not associated with different outcomes compared with no stenting (mRS 0-2: 75.8% vs 66.0%, adjusted OR 2.0, 95% CI 0.8 to 5.1).

CONCLUSIONS

Tandem cervical carotid occlusion in patients with acute large vessel stroke did not lower the odds of good functional outcome in our study. Functional outcomes were similar irrespective of the management of the cervical ICA occlusion (stenting vs not stenting).

Global impact of COVID-19 on stroke care

Background

The COVID-19 pandemic led to profound changes in the organization of health care systems worldwide.

Aims

We sought to measure the global impact of the COVID-19 pandemic on the volumes for mechanical thrombectomy, stroke, and intracranial hemorrhage hospitalizations over a three-month period at the height of the pandemic (1 March–31 May 2020) compared with two control three-month periods (immediately preceding and one year prior).

Methods

Retrospective, observational, international study, across 6 continents, 40 countries, and 187 comprehensive stroke centers. The diagnoses were identified by their ICD-10 codes and/or classifications in stroke databases at participating centers.

Results

The hospitalization volumes for any stroke, intracranial hemorrhage, and mechanical thrombectomy were 26,699, 4002, and 5191 in the three months immediately before versus 21,576, 3540, and 4533 during the first three pandemic months, representing declines of 19.2% (95%CI, −19.7 to −18.7), 11.5% (95%CI, −12.6 to −10.6), and 12.7% (95%CI, −13.6 to −11.8), respectively. The decreases were noted across centers with high, mid, and low COVID-19 hospitalization burden, and also across high, mid, and low volume stroke/mechanical thrombectomy centers. High-volume COVID-19 centers (−20.5%) had greater declines in mechanical thrombectomy volumes than mid- (−10.1%) and low-volume (−8.7%) centers (p < 0.0001). There was a 1.5% stroke rate across 54,366 COVID-19 hospitalizations. SARS-CoV-2 infection was noted in 3.9% (784/20,250) of all stroke admissions.

Conclusion

The COVID-19 pandemic was associated with a global decline in the volume of overall stroke hospitalizations, mechanical thrombectomy procedures, and intracranial hemorrhage admission volumes. Despite geographic variations, these volume reductions were observed regardless of COVID-19 hospitalization burden and pre-pandemic stroke/mechanical thrombectomy volumes.

Expanding indications for endovascular thrombectomy-how to leave no patient behind

Endovascular thrombectomy (EVT) has become standard of care for large vessel occlusion strokes but current guidelines exclude a large proportion of patients from this highly effective treatment. This review therefore focuses on expanding indications for EVT in several borderline indications such as patients in the extended time window, patients with extensive signs of infarction on admission imaging, elderly patients and patients with pre-existing deficits. It also discusses the current knowledge on intravenous thrombolysis as an adjunct to EVT and EVT as primary therapy for distal vessel occlusions, for tandem occlusions, for basilar artery occlusions and in pediatric patients. We provide clear recommendations based on current guidelines and further literature.

Abstract P316: Non-Stenotic Carotid Plaques in Ischemic Stroke - Analysis of the STRATIS Registry

Objective: To determine the prevalence of non-stenotic carotid plaques (<50%) and their association with ipsilateral strokes.

Methods: Data was analyzed from the STRATIS registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)—a prospective, nonrandomized study of patients undergoing thrombectomy with the Solitaire device. Prevalence of non-stenotic carotid plaques, ipsilateral and contralateral to the stroke was compared in patients with ESUS and cardioembolic strokes. Plaque features were further compared within both subgroups between patients with and without ipsilateral stroke. Uni- and multivariable logistic regression was performed to determine associations between non-stenotic carotid plaque, plaque characteristics, and ipsilateral stroke in both subgroups.

Results: Of the 946 patients in the database, 226 patients with cardioembolic stroke (median age, 72 years) and 141 patients with ESUS (median age, 69 years) were included in the analysis.The prevalence of non-stenotic carotid plaque in the cardioembolic and ESUS subgroups was 33/226 (14.6%) and 32/141(22.7%) respectively. Bilateral non-stenotic carotid plaques were seen in 10/226(4.4%) cardioembolic and 13/141(9.2%) ESUS patients. Non-stenotic carotid plaques were significantly associated with ipsilateral strokes in cardioembolic stroke (aOR,1.91 [95% CI,1.15-3.18]) and in ESUS (aOR,1.69 [95% CI, 1.05-2.73]). Plaque irregularity, plaque hypodensity and increasing plaque thickness were significantly associated with ipsilateral stroke, only in the ESUS subgroup.

Conclusion: Non-stenotic carotid plaques were significantly associated with ipsilateral stroke in cardioembolic and ESUS subgroups and there was increased association of hypodense plaque, increasing plaque thickness and plaque irregularity with ipsilateral stroke in the ESUS subgroup, suggesting these plaques could be a potential cause of stroke in these patient subgroups.

Abstract P498: Quality of Reperfusion - Association of Stent Retriever Characteristics and Successful Reperfusion in ESCAPE-NA1 Dataset

Background: We evaluated technical aspects of stent retriever use and its relation to reperfusion in ESCAPE NA1 trial.

Methods: ESCAPE-NA1 was a multicenter, international randomized trial assessing the efficacy of nerinetide in ischemic stroke patients who underwent EVT within 12h from onset. The following stent retriever characteristics were evaluated: stent retriever length, diameter, thrombus position in relation to stent retriever - proximal, middle or distal third, bypass effect during stent retriever deployment (Figure 1), and stent retriever placement in the anterior or posterior MCA trunk (in M1 occlusions). Primary outcome was reperfusion grade and the unit of analysis was stent retriever attempt.

Results: Data from 1062 patients were evaluated. Angiographic data for up to three passes were analyzed as only 8.9% of patients required >3 passes. Stent retriever was used in 1241 passes in 808 patients. The occlusion sites were terminal ICA (14.9%), M1 MCA (58.7%), M2 MCA (23.7%), other (2.1%). A successful reperfusion attempt (mTICI 2b-3) was associated with the presence of bypass effect (OR 1.7; 95%CI 1.07-2.72), and positioning of stent retriever so the thrombus was in the proximal and middle third of stent retriever (OR 2.06; 95%CI 1.24-3.40 and OR 1.92; 95%CI 1.16-3.15, respectively). The position of the thrombus in the middle third of stent retriever was a significant predictor of bypass effect (OR 2.71; 95%CI 1.61-4.58). Stent retriever length, diameter, or choice of MCA trunk did not predict successful attempts, Table 1.

Conclusion: Bypass effect and positioning of stent retriever so the thrombus was in proximal 2/3rds are predictors of successful reperfusion attempts.

Abstract P524: Impact of Intra-Procedural Workflow and Time Metrics of Establishing Fast Reperfusion on Clinical Outcomes in the ESCAPE-NA1 Trial

Background: Time from imaging to establishing reperfusion is a major influencer of clinical outcomes and over the years thrombectomy techniques have evolved rapidly. This has led to improvements in achieving fast and complete reperfusion. We analyzed the impact of various intra-procedural techniques and tools on the speed of reperfusion and correlated procedural duration with probability of achieving good clinical outcomes.

Methods: We analyzed intra-procedural time metrics and examined factors leading to delays during EVT. The relationship between outcome (mRS Scale) and procedural time from arterial puncture to time of achieving mTICI 2b-3 First Reperfusion (FRE) was modeled using logistic regression.

Results: The various procedural time metrics are summarized in Figure 1. Every 10-minute increase in FRE time reduced the probability of achieving functional independence(90-day modified Rankin Scale 0-2) by 6.7% (P=0.021, adjusted). The medianFRE timewas 25min (IQR 17-39) and was significantly longer in patients with tandem occlusions(median 34min, p 0.0005). General anesthesia vs procedural sedation vs no sedation use did not significantly alter the FRE time (p = 0.1453). The use of BGC (54.2%) was nominally longer FRE (median 26min “IQR 18-38” vs 23ming, “IQR 16-38”; p 0.095)while the use of contact aspiration (n=213) vs retrievable stents (n=676) as the first approach was associated with a shorter FRE time (21min “IQR 14-35” vs 26 min “IQR18-40”, p =0.001).

Conclusions: Puncture to first reperfusion time is a significant predictor of clinical outcome in theESCAPE-NA1 trial. Various procedural and anatomical factors influence this timemetric.

Figure: Intra-Procedural workflow time metrics expressed in medians and 90th percentiles. The cumulative times are calculated for each major milestone in the procedure for upto three attempts. First reperfusion duration where TICI 2b was achieved is shown in comparison to other procedural time metrics.

Abstract P550: Incidence, Predictors and Impact of Emboli in New Territory in Escape NA1 Trial

Introduction: Emboli in new territory (ENT) are known potential complication of endovascular thrombectomy. We explored their incidence and predictors in ESCAPE-NA-1 trial.

Methods: We included patients from the ESCAPE-NA1: a multicenter, international randomized study that assessed the efficacy of intravenous nerinetide in patients with acute ischemic stroke who underwent EVT within 12 hours from onset. All the imaging was reassessed, and ENT was defined as angiographic evidence of emboli in vascular territories other than the MCA, which was not present in the initial CT angiogram. We collected details of management and its influence on outcomes.

Results: We analyzed 1095 patients from the ESCAPE NA1. ENT occurred in 40 patients (3.6%, mean age 69.5 years, 50% females). There were no significant differences at baseline in groups with and without ENT. Most common ENT site was ACA (38,95%). Thrombolysis, use of balloon guide catheter, nerinetide treatment, and initial occlusion site did not predict ENT. Seven ENTs (17.5%) were pursued with endovascular therapy: retrievable stents in 6 patients and intra-arterial thrombolysis in 1 patient. Patients with ENT had longer total arterial puncture to first reperfusion times (65 vs 40.5 minutes, P<0.001), and a higher final median infarct volume compared to those without ENT (77.9 vs 24.2, P<0.001). On multivariable analysis, presence of ENT was a negative predictor of clinical outcome (mRS 0-2) after adjustment for age, sex, NIHSS, ASPECTS and successful reperfusion (OR 0.26, 95%CI 0.13-0.55).

Conclusion: The incidence of ENT was low in ESCAPE NA1 trial but associated with poorer clinical outcomes.

Abstract P535: Quality of Reperfusion and Clinical Outcome in ESCAPE-NA1 Trial

Background: We evaluated clinical outcome in relation to the degree of reperfusion in ESCAPE-NA1 trial.

Methods: ESCAPE-NA1 was a multicenter, international randomized trial assessing the efficacy of nerinetide in ischemic stroke patients who underwent EVT within 12h from onset. Independent clinical outcome [90-days modified Rankin Scale (mRS) 0-2], excellent clinical outcome (90-days mRS 0-1), isolated subarachnoid hemorrhage with no parenchymal hemorrhage (iSAH) or symptomatic hemorrhage (sICH) on follow-up imaging, and death were compared between a treatment group and control group with respect to the level of reperfusion defined as mTICI. Univariable and multivariable logistic regression analyses were performed.

Results: Data from 1090 patients were assessed. The occlusion locations were terminal ICA (18.3%), M1 MCA (61.8%,) M2 MCA (15.1%), other - e.g. M3 (3.7%). Final mTICI 0-1 was achieved in 5.5% of patients, mTICI 2a in 7.5%, mTICI 2b in 40.8%, mTICI 2c in 26.6% and mTICI 3 in 19.5%. Isolated SAH was present in 1.7% and sICH in 3%. There was no significant difference between the nerinetide and control groups in the reperfusion grade, presence of iSAH or sICH, or in clinical outcome. Odds of independent outcomes (mRS 0-2) and odds of excellent outcome (mRS 0-1) were significantly increasing with each improved reperfusion grade, Table 1. Sixty percent of patients with final mTICI 2b, 70% with mTICI 2c and 69% with mTICI 3 achieved good clinical outcome in comparison to 30% of patients with mTICI 0-2a. The incidence of iSAH was significantly lower in the NA1 arm (OR 0.28, 95%CI: 0.09-0.86, p=.027) adjusting for reperfusion status.

Conclusion: Degrees of better reperfusion are strongly associated with better outcomes and reduced mortality. mTICI 2c-3 reperfusion should be a standard goal of EVT.

Abstract P338: Incidence, Predictors and Impact of Infarct in New Territory in Escape Na1 Trial

Introduction: Infarct in new territory (INT) is a known complication of endovascular therapy. We assessed the prevalence, predictors and clinical relevance of INT

Methods: We included patients from the ESCAPE-NA1: a multicenter, international randomized study that assessed the efficacy of intravenous nerinetide in patients with acute ischemic stroke who underwent EVT within 12 hours from onset. All imaging was re-evaluated, and INT was defined by presence of infarct in new vascular territory, outside the baseline target occlusion(s) on follow up CT and MRI. INT’s were classified by maximum diameter (<2mm, 2-20mm and >20mm) and location.

Results: Of 1099 analyzed patients in ESCAPE NA1, 107 had INT (9.7%, mean age 67 years, 51.4% females). There were no differences at baseline in those with vs without INT. Most INTs (75.7%) were angiographically occult and 41(38.3%) were > 20mm. The most common INT territory was the ACA alone or in combination with MCA/PCA (30.3%). The presence of emboli in new territory angiographically was significantly associated with INT (OR 16.39, 95%CI 8.14-33.09). Alteplase use, balloon guide catheter use, nerinetide and initial occlusion site did not predict INT. INT patients had higher final median infarct volumes compared to non-INT (44.5cc vs 23.3cc, P<0.001). Large INT (diameter of >20mm) were associated with poor clinical outcome compared to INT (<2mm) OR (mRS 0-2) 0.17, 95%CI 0.05-0.55).

Conclusion: Infarcts in new territory are common and are associated with poor outcome.

Abstract P485: Predictors and Clinical Impact of Deep Grey Matter Infarction After Endovascular Treatment for Large Vessel Occlusion Stroke: Results From the Escape-NA1 Trial

Purpose: In this post-hoc analysis of the ESCAPE-NA1 trial, we investigated the prevalence of deep grey matter infarcts and their influence on clinical outcome.

Methods: Infarcts on 24 hour follow up imaging (non contrast head CT or diffusion-weighted MRI) were categorized as predominantly deep grey matter infarcts (caudate and/or lentiform nucleus infarcts with sparing of the superficial grey matter and white matter) vs. other infarcts. Total infarct volume was manually segmented in all patients. When MRI follow-up was available, deep grey matter and grey matter infarct volumes were segmented separately. Multivariable logistic regression with adjustment for key minimization variables and by infarct volume was used to assess the association of predominantly deep grey matter infarcts and good outcome.

Results: Of the 1026 included patients, 316 (30.8%) had predominantly deep grey matter infarcts. Cumulative proportions of good outcome for overall, grey matter, deep grey matter, and superficial grey matter infarct volumes are shown in the figure. Good outcomes were more frequently achieved in patients with predominantly deep grey matter infarcts (239/316 [75.6%] vs. 374/704 [53.1%]). Deep infarcts were tightly correlated with infarct volume (Pearson rho -0.35) and in multivariable analysis deep grey matter infarcts were predictive of outcome overall; when examined in volume percentiles, there was no effect of deep infarct location.

Conclusion: Predominantly deep grey matter infarcts are associated with good outcomes. Deep grey matter infarct location favorable prognosis is associated with small overall infarct size.

Abstract P538: A Detailed Analysis of Intracranial Hemorrhage After Endovascular Treatment in Acute Ischemic Stroke Due to Large Vessel Occlusion in the Escape-NA1 Trial

Purpose: We investigated the prevalence and prognostic impact on outcome of any intracranial hemorrhage, hemorrhage morphology, type and volume in acute ischemic stroke patients undergoing mechanical thrombectomy.

Methods: Prevalence of intracranial hemorrhage, hemorrhage type, morphology and volume was determined on 24h follow-up imaging (non contrast head CT or gradient-echo/susceptibility-weighted MRI). Proportions of good outcome (mRS 0-2 at 90 days) were reported for patients with vs. without any intracranial hemorrhage. Multivariable logistic regression with adjustment for key minimization variables and total infarct volume was performed to obtain adjusted effect size estimates for hemorrhage type and volume on good outcome.

Results: Hemorrhage on follow up-imaging was seen in 372/1097 (33.9%) patients, among them 126 (33.9%) with hemorrhagic infarction (HI) type 1, 108 (29.0%) with HI-2, 72 /19.4%) with parenchymal hematoma (PH) type 1, 37 (10.0) with PH2, 8 (2.2%) with remote PH and 21 (5.7%) with extra-parenchymal/intraventricular hemorrhage. Good outcomes were less often achieved by patients with hemorrhage on follow-up imaging (164/369 [44.4%] vs. 500/720 [69.4%]). Any type of intracranial hemorrhage was strongly associated with decreased chances of good outcome ( adj OR 0.62 [CI 95 0.44 - 0.87]). The effect of hemorrhage was driven by both PH hemorrhage sub-type [PH-1 ( adj OR 0.39 [CI 95 0.21 - 0.72]), PH-2 ( adj OR 0.15 [CI 95 0.05 - 0.50])] and extra-parenchymal/intraventricular hemorrhage ( adj OR 0.60 (0.20-1.78) Petechial hemorrhages (HI-1 and HI-2) were not associated with poorer outcomes. Hemorrhage volume ( adj OR 0.97 [CI 95 0.05 - 0.99] per ml increase) was significantly associated with decreased chances of good outcome.

Conclusion: Presence of any hemorrhage on follow-up imaging was seen in one third of patients and strongly associated with decreased chances of good outcome.

Abstract P375: Cortical Venous Opacification Patterns and Outcome in Patients With Tandem Carotid Occlusion - Results From the ESCAPE NA1-Trial

Background: The degree of cortical venous opacification could reflect the degree of ischemia in tandem occlusions strokes. We assessed the association between asymmetric cortical vein opacification and outcome among patients with acute ischemic stroke and tandem occlusion.

Methods: ESCAPE NA1 was a multicenter randomized-controlled trial comparing medical treatments nerinetide vs. placebo in patients with acute ischemic stroke and large vessel occlusion who underwent EVT. Tandem carotid occlusion was defined as complete occlusion of the ICA on catheter angiography. We assessed cortical venous opacification on baseline CTA using the COVES score (Jansen, et al. Radiology 2019, ranging from 0-6 with lower numbers indicating poor cortical venous filling, and dichotomized to 0 vs. 1-6). The influence of cortical venous opacification on functional outcome was analyzed using regression modelling with adjustment for age, baseline NIHSS and ASPECTS, thrombolysis and treatment allocation.

Results: We assessed 115 patients with tandem occlusion. Median COVES score was 2 (IQR 1-3) with 9 patients (8%) scoring 0 (complete absence of cortical venous filling). Patients with COVES 0 were less likely to have good leptomeningeal collaterals (good collaterals: COVES 0: 0/9 (0%) vs. COVES 1-6: 19/102 (18%), p = 0.007). Patients with COVES 0 were less likely to achieve good outcome (mRS 0-2, COVES 0: 3/9 patients (33%) vs. COVES 1-6: 79/106 (74%), p=0.016). Cortical venous filling was significantly associated with good functional outcome on univariable analysis (OR 5.9, 95%CI 1.4 - 25.0), and after adjustment for baseline variables (OR 8.6, 95%CI 1.4 - 51.0). Cervical carotid angioplasty and/or stenting did not modify functional outcome after adjustment for COVES score.

Conclusion: Impaired venous drainage is a marker of poor pial collaterals and is associated with poorer outcome in tandem occlusion patients.

Abstract P542: Management and Outcome of Stroke Patients With Tandem Carotid Occlusion in the ESCAPE NA1-Trial

Background: The optimal treatment for stroke patients with tandem cervical carotid occlusion is debated. We analyzed the treatment strategies and outcomes of tandem occlusion patients in the ESCAPE NA1 trial.

Methods: ESCAPE NA1 was a multicenter international randomized trial of nerinetide vs. placebo in patients with acute ischemic stroke who underwent EVT. We defined tandem occlusions as complete occlusion of the cervical ICA on catheter angiography. The influence of tandem occlusions on outcome was analyzed using regression modeling with adjustment for age, sex, baseline NIHSS and ASPECTS, occlusion location, thrombolysis and treatment allocation.

Results: 115 of 1105 patients (10.4%) had tandem occlusions. 73/115 tandem patients (66.0%) received treatment for the cervical occlusion: 21.9% were stented before thrombectomy, 68.5% were stented after thrombectomy, and 8.2% had angioplasty alone. Successful reperfusion was significantly higher in patients who had thrombectomy first followed by carotid treatment (eTICI 2b-3: 40/40 (100.0%)) or carotid angioplasty before and cervical stent after intracranial thrombectomy (9/10 (90.0%)) compared to carotid intervention before intracranial thrombectomy: (19/23 (82.1%), p=0.016). 90-day mRS 0-2 was achieved in 82/115 patients (71.3%) with tandem occlusions (treated occlusions: 74.0%, untreated: 66.7%) compared to 579/981 (59.5%) patients without tandem occlusions. In adjusted analysis, tandem occlusion was not predictive of outcome. In the subgroup of tandem patients, cervical stent-treatment was nominally associated with better outcomes (OR 2.2, 95% CI 0.5 - 9.2).

Conclusion: Cervical carotid stenting may improve outcomes for EVT patients with tandem occlusions, but these results are limited by the sample size and non-randomized selection of patients for stenting.

Abstract P490: Influence of Balloon Guide Catheter Use on Procedural & Clinical Outcomes in the Escape-NA1 Trial

Purpose: We assessed whether balloon guide catheter (BGC) use during endovascular thrombectomy (EVT) influences procedural and clinical outcomes in the ESCAPE-NA1 trial.

Methods: ESCAPE-NA1 was an international multicenter trial that randomized large vessel occlusion stroke patients who underwent endovascular thrombectomy (EVT) to receive Nerinetide vs. placebo. Information on EVT techniques and devices was extracted from angiographic images and procedure report forms. Effect estimates of BGC use on angiographic and clinical outcomes were obtained with logistic regression with adjustment for age, ASPECTS, baseline NIHSS, occlusion site, alteplase and study drug treatment.

Results: Detailed information on EVT devices and technique was available for 891/1105 (80.6%) patients. A BGC was used in 599/891 patients (67.2%). BGC use was most common with a retrievable stent use (with or without distal access catheter) as the first-line approach (in 252/266 cases [94.7%] vs. combined approach (both aspiration and SR): 288/414 [69.6%], vs. contact aspiration: 37/159 cases [23.3%]). Overall, eTICI 2b/3 rates with vs. without BGC did not differ significantly (525/598 [87.8%] vs. 260/292 [89.0%]), but eTICI 2c/3 rates were significantly higher when a BGC was used (304/598 [50.8%] vs. 126/292 [43.2%], adjusted OR 1.39 [95%CI 1.05 - 1.9]). Good outcomes (mRS 0-2) were not associated with BGC use (adjusted OR 1.07 [95%CI 0.78 - 1.48]).

Conclusion: BGC use was associated with a greater proportion of near-complete reperfusion, while there was no significant association with clinical outcomes.

Clinical outcomes of isolated deep grey matter infarcts after endovascular treatment of large vessel occlusion stroke

PURPOSE

There are few data on the prevalence and impact of isolated deep grey matter infarction in acute stroke. In this study, we aimed to investigate the prevalence of isolated deep grey matter infarcts and their impact on the outcome.

METHODS

Infarcts on 24-h follow-up imaging (non-contrast head CT or diffusion-weighted MRI) in the ESCAPE-NA1 trial were categorized into predominantly deep grey matter infarcts vs. infarcts involving additional territories ("other infarcts"). Total infarct volume was manually segmented. Baseline characteristics and proportions of good outcome (primary outcome, defined as modified Rankin Score [mRS] 0-2 at 90 days), excellent outcome (mRS 0-1) and mortality were compared between patients with and without predominantly deep grey matter infarcts. Multivariable logistic regression with adjustment for baseline variables and total infarct volume was used to determine a possible association of predominantly deep grey matter infarcts and clinical outcome.

RESULTS

Predominantly deep grey matter infarcts were seen in 316/1026 patients (30.8%). Compared to other patients, their ASPECTS was higher, collateral status and reperfusion quality were better and time to treatment was shorter. Good outcome was seen in 239/316 (75.6%) with vs. 374/704 (53.1%) without predominantly deep grey matter infarcts. After adjusting for baseline variables and total infarct volume, predominantly deep grey matter infarcts were independently associated with excellent outcome (_adjOR: 1.45 [CI₉₅: 1.04-2.02]), but not with good outcome (_adjOR: 1.24 [CI₉₅: 0.86-1.80]) or mortality (_adjOR: 0.73 [CI₉₅:0.39-1.35]) CONCLUSION: Predominantly deep grey matter infarct patterns were seen in 1/3rd of patients and were significantly associated with increased chances of excellent outcome, independent of patient baseline status and infarct size.

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.

Combined Effect of Age and Baseline Alberta Stroke Program Early Computed Tomography Score on Post-Thrombectomy Clinical Outcomes in the MR CLEAN Registry

BACKGROUND AND PURPOSE

Ischemic brain tissue damage in patients with acute ischemic stroke, as measured by the Alberta Stroke Program Early CT Score (ASPECTS) may be more impactful in older than in younger patients, although this has not been studied. We aimed to investigate a possible interaction effect between age and ASPECTS on functional outcome in acute ischemic stroke patients undergoing endovascular treatment, and compared reperfusion benefit across age and ASPECTS subgroups.

METHODS

Patients with ischemic stroke from the MR CLEAN Registry (Multicenter Randomized Clinical Trial of Endovascular Treatment for Acute Ischemic Stroke in the Netherlands; March 2014-November 2017) were included. Multivariable ordinal logistic regression was performed to obtain effect size estimates (adjusted common odds ratio) on functional outcome (modified Rankin Scale score) for continuous age and granular ASPECTS, with a 2-way multiplicative interaction term (age×ASPECTS). Outcomes in four patient subgroups based on age (< versus ≥ median age [71.8 years]) and baseline ASPECTS (6-10 versus 0-5) were assessed.

RESULTS

We included 3279 patients. There was no interaction between age and ASPECTS on modified Rankin Scale (P=0.925). The highest proportion of modified Rankin Scale 5 to 6 was observed in patients >71.8 years with baseline ASPECTS 0 to 5 (68/107, 63.6%). There was benefit of reperfusion in all age-ASPECTS subgroups. Although the adjusted common odds ratio was lower in patients >71.8 years with ASPECTS 0 to 5 (adjusted common odds ratio, 1.60 [95% CI, 0.66-3.88], n=110), there was no significant difference from the main effect (P=0.299).

CONCLUSIONS

Although the proportion of poor outcomes following endovascular treatment was highest in older patients with low baseline ASPECTS, outcomes did not significantly differ from the main effect. These results do not support withholding endovascular treatment based n a combination of high age and low ASPECTS.

[Management of unruptured intracranial Aneurysms]

Management of unruptured intracranial Aneurysms Abstract. Unruptured intracranial aneurysms (UIAs) are a common coincidental finding in cranial imaging of patients with non-correlated symptoms such as headache or dizziness. With an estimated prevalence of around 1 - 2 % in the general population, these UIAs often present clinicians with difficult decisions. This is particularly the case since, despite extensive research in this area, the natural course of UIAs is still poorly understood and the risk of rupture cannot be specified. Due to often catastrophically clinical outcomes as a result of an aneurysmal subarachnoid haemorrhage (mortality-rates of up to 51 %), the desire for intervention and the emotional burden on the patient in the case of diagnosis of an UIA is often very high. For this reason, the knowledge of average rupture rates, factors that influence them, but also knowledge of the complication rates and the result of interventions is essential for the clinician in order to arrive together with the patient at a responsible and reasonable decision regarding the treatment of an UIA. In this review, we present the current state of science regarding the natural course of UIAs, the possibilities of intervention and strategies in patient management based on current guidelines.

Physician factors influencing endovascular treatment decisions in the management of unruptured intracranial aneurysms

PURPOSE

Deciding about whether an unruptured intracranial aneurysm (UIA) should be treated or not is challenging because robust data on rupture risks, endovascular treatment complication rates, and treatment success rates are limited. We aimed to investigate how neurointerventionalists conceptually approach endovascular treatment decision-making in UIAs.

METHODS

In a web-based international multidisciplinary case-based survey among neurointerventionalists, participants provided their demographics and UIA treatment-volumes, estimated 5-year rupture rates, endovascular treatment complication and success rates and gave their endovascular treatment decision for 15 pre-specified UIA case-scenarios. Differences in estimated 5-year rupture rates, endovascular treatment complication and success rates based on physician and hospital characteristics were evaluated with the Kruskal-Wallis test. Multivariable logistic regression analysis was used to derive adjusted effect size estimates for predictors of endovascular treatment decision.

RESULTS

Two hundred-thirty-three neurointerventionalists from 38 countries participated in the survey (median age 47 years [IQR: 41-55], 25/233 [10.7%] females). The ranges of estimates for 5-year rupture risks, endovascular treatment complication rates, and particularly endovascular treatment success rates were wide, especially for UIAs in the posterior circulation. Estimated 5-year rupture risks, endovascular treatment complication and success rates differed significantly based on personal and institutional endovascular UIA treatment volume, and all three estimates were significantly associated with physicians' endovascular treatment decision.

CONCLUSION

Although several predictors of endovascular treatment decision were identified, there seems to be a high degree of uncertainty when estimating rupture risks, treatment complications, and treatment success for endovascular UIA treatment. More data on the clinical course of UIAs with and without endovascular treatment is needed.

Abstract WMP22: Synthetic Image Based Deep Learning of Stroke DWI Lesion Segmentation

Introduction: The application of deep learning to stroke image analysis (and medical images in general) faces two major challenges: first, it requires a large number of images to train, which is difficult to obtain. Second, the accurate outlining of infarcts is tedious, requires a high level of expertise, is subjective and error prone. The purpose of this work was to produce a large set of diffusion-weighted images (DWI) with perfectly defined realistic-appearing synthetic acute stroke lesions and to compare the segmentation performance of a deep neural network trained on these DWI scans with synthetic stroke lesions to a network trained on DWI scans of real stroke patients with stroke lesions manually outlined by neuroradiologists.

Methods: 449 DWI scans with stroke lesions (72 ± 14y) and 2027 normal DWI scans (38 ± 24y) were coregistered, resampled, cropped to 96 x 80 x 40 voxels, normalized and divided into training/testing sets (80/20%). Stroke lesions were manually segmented by 3 neuroradiologists. 2000 synthetic 3D stroke DWI were produced by fusing thresholded (min 8%) signal increase of random DWI lesions to random coregistered normal DWI ( A ). A 3D U-Net (Tensorflow, depth 3, initial 64 feature maps doubled with each downsampling, bottleneck 3; hyperparameters optimized with cross-validation) was trained separately on 3 datasets: human-labeled real stroke cases (HL); 2000 synthetic cases (S); human-labeled real stroke cases + 2000 synthetic cases (HL+S).

Results: The model trained on the human-labeled real stroke cases + 2000 synthetic cases (average dice coefficient between 300 and 600 epochs= 0.66±0.14) significantly outperformed the model trained on the 2000 synthetic cases only (0.60±0.14) and the model trained on human-labeled real stroke cases only (0.55±0.18; p<10 -29 for all comparisons) ( B-C ).

Conclusions: Deep learning segmentation of acute stroke lesions was significantly improved and was more stable by using synthetically generated images.

Role of cerebral endothelial cells in the astrocyte swelling and brain edema associated with acute hepatic encephalopathy

Brain edema is an important complication of acute hepatic encephalopathy (AHE), and astrocyte swelling is largely responsible for its development. Elevated blood and brain ammonia levels have been considered as major etiological factors in this edema. In addition to ammonia, recent studies have suggested that systemic infection, inflammation (and associated cytokines (CKs)), as well as endotoxin (lipopolysaccharide (LPS)) are also involved in AHE-associated brain edema. As endothelial cells (ECs) are the first resident brain cells exposed to blood-borne "noxious agents" (i.e., ammonia, CKs, LPS) that are present in AHE, these cells may be in a critical position to react to these agents and trigger a process resulting in astrocyte swelling/brain edema. We therefore examined the effect of conditioned media (CM) from ammonia, LPS and cytokine-treated cultured brain ECs on cell swelling in cultured astrocytes. CM from ammonia-treated ECs when added to astrocytes caused significant cell swelling, and such swelling was potentiated when astrocytes were exposed to CM from ECs treated with a combination of ammonia, LPS and CKs. We also found an additive effect when astrocytes were exposed to ammonia along with CM from ammonia-treated ECs. Additionally, ECs treated with ammonia showed a significant increase in the production of oxy-radicals, nitric oxide (NO), as well as evidence of oxidative/nitrative stress and activation of the transcription factor nuclear factor kappa B (NF-κB). CM derived from ECs treated with ammonia, along with antioxidants (AOs) or the NF-κB inhibitor BAY 11-7082, when added to astrocytes resulted in a significant reduction in cell swelling, as compared to the effect of CM from ECs-treated only with ammonia. We also identified increased nuclear NF-κB expression in rat brain cortical ECs in the thioacetamide (TAA) model of AHE. These studies suggest that ECs significantly contribute to the astrocyte swelling/brain edema in AHE, likely as a consequence of oxidative/nitrative stress and activation of NF-κB.

[Activity and cost analysis in surgical pathology. Experience of a French university laboratory using the activity-based costing method]

Good self-knowledge enables us to have a well- reasoned adaptation to our environment. Starting from this precept based on simple common sense, activity and cost analysis, when applied to medical departments in a university hospital setting, represents a necessary phase in their scientific progression and in the continuation of their university vocation. This is all the more true given the present climate of economic and organizational restructuring of medical facilities. This paper relates the experience of a French surgical pathology department which was assessed for cost effectiveness using the Activity-Based Costing (ABC) method in 1999. This method, which originated in the business world and of which the general concepts are presented here, has given us a keener understanding of the diverse processes involved, their costs and how these costs are arrived at. Moreover, this method has identified the proportion of costs imputable to diagnostic work and of those linked to work specific to a university hospital, in particular teaching and research and development. The results can then be used for a clearer analysis of the figures required by prescribers and health care funding agencies, and, within the department, to enhance perception of work carried out by the entire staff in order to initiate a new type of management centered on activity (Activity-Based Management). Adaptable to any medical department, whatever its organizational structure, independent of the significance of any given code letter and regardless of the rating method used to grade activities, the ABC method also allows for comparisons between structures of a similar nature. The thoughts it inspires on economic performance must take into account the rules of good medical practice, the imperatives of quality assurance, the need for "breathing space" which are indispensable to research and a humanist conception of working relations.