The VEBAS score: a practical scoring system for intracranial dural arteriovenous fistula obliteration

BACKGROUND

Tools predicting intracranial dural arteriovenous fistulas (dAVFs) treatment outcomes remain scarce. This study aimed to use a multicenter database comprising more than 1000 dAVFs to develop a practical scoring system that predicts treatment outcomes.

METHODS

Patients with angiographically confirmed dAVFs who underwent treatment within the Consortium for Dural Arteriovenous Fistula Outcomes Research-participating institutions were retrospectively reviewed. A subset comprising 80% of patients was randomly selected as training dataset, and the remaining 20% was used for validation. Univariable predictors of complete dAVF obliteration were entered into a stepwise multivariable regression model. The components of the proposed score (VEBAS) were weighted based on their ORs. Model performance was assessed using receiver operating curves (ROC) and areas under the ROC.

RESULTS

A total of 880 dAVF patients were included. Venous stenosis (presence vs absence), elderly age (<75 vs ≥75 years), Borden classification (I vs II-III), arterial feeders (single vs multiple), and past cranial surgery (presence vs absence) were independent predictors of obliteration and used to derive the VEBAS score. A significant increase in the likelihood of complete obliteration (OR=1.37 (1.27-1.48)) with each additional point in the overall patient score (range 0-12) was demonstrated. Within the validation dataset, the predicted probability of complete dAVF obliteration increased from 0% with a 0-3 score to 72-89% for patients scoring ≥8.

CONCLUSION

The VEBAS score is a practical grading system that can guide patient counseling when considering dAVF intervention by predicting the likelihood of treatment success, with higher scores portending a greater likelihood of complete obliteration.

Endovascular treatment of dural arteriovenous fistulas involving the vein of Galen: a single-center cohort and meta-analysis

BACKGROUND

Dural arteriovenous fistulas (dAVFs) draining into the vein of Galen (VoG) are complex lesions that often necessitate treatment to minimize the risk of rupture and relieve symptoms. These lesions can be treated with open surgical resection, radiosurgery, or endovascular embolization. Unfortunately, endovascular treatment of dAVFs involving the VoG has not been robustly assessed across large patient cohorts. To meet this need, we performed a retrospective review of dAVFs involving the VoG at our center, and included these in a meta-analysis to identify the safety and efficacy of endovascular embolization, as well as describing current treatment trends for this disease.

METHODS

Consecutive patients with dAVFs involving the VoG treated at a single center were identified from a prospective database and retrospectively reviewed. A literature search was conducted with defined search criteria, and eligible studies were included alongside our cohort in a meta-analysis. Rates of complete dAVF treatment and clinical complications were pooled across studies with a random effects model and reported with a 95% CI.

RESULTS

Five dAVFs involving the VoG were treated endovascularly at our center during the study period. In this series, 80% of treatments led to complete occlusion of the fistula while no patients had clinical complications. Onyx was used for all treatments. In our meta-analysis, the overall rate of complete occlusion was 72.0% (95% CI 59.8% to 84.1%) and the overall rate of clinical complications was 10.0% (95% CI 4.7% to 15.3%).

CONCLUSIONS

Endovascular approaches for dAVFs involving the VoG are technically feasible, but carry a risk of clinical complications. Future work should identify optimal endovascular embolic agents.

Natural history, angiographic presentation and outcomes of anterior cranial fossa dural arteriovenous fistulas

BACKGROUND

Anterior cranial fossa dural arteriovenous fistulas (ACF-dAVFs) are aggressive vascular lesions. The pattern of venous drainage is the most important determinant of symptoms. Due to the absence of a venous sinus in the anterior cranial fossa, most ACF-dAVFs have some degree of drainage through small cortical veins. We describe the natural history, angiographic presentation and outcomes of the largest cohort of ACF-dAVFs.

METHODS

The CONDOR consortium includes data from 12 international centers. Patients included in the study were diagnosed with an arteriovenous fistula between 1990-2017. ACF-dAVFs were selected from a cohort of 1077 arteriovenous fistulas. The presentation, angioarchitecture and treatment outcomes of ACF-dAVF were extracted and analyzed.

RESULTS

60 ACF-dAVFs were included in the analysis. Most ACF-dAVFs were symptomatic (38/60, 63%). The most common symptomatic presentation was intracranial hemorrhage (22/38, 57%). Most ACF-dAVFs drained through cortical veins (85%, 51/60), which in most instances drained into the superior sagittal sinus (63%, 32/51). The presence of cortical venous drainage predicted symptomatic presentation (OR 9.4, CI 1.98 to 69.1, p=0.01). Microsurgery was the most effective modality of treatment. 56% (19/34) of symptomatic patients who were treated had complete resolution of symptoms. Improvement of symptoms was not observed in untreated symptomatic ACF-dAVFs.

CONCLUSION

Most ACF-dAVFs have a symptomatic presentation. Drainage through cortical veins is a key angiographic feature of ACF-dAVFs that accounts for their malignant course. Microsurgery is the most effective treatment. Due to the high risk of bleeding, closure of ACF-dAVFs is indicated regardless of presentation.

Predictors of tissue infarction from distal emboli after mechanical thrombectomy

BACKGROUND

Distal embolization after endovascular thrombectomy (EVT) is common. We aimed to determine factors associated with tissue infarction in the territories of distal emboli.

METHODS

This is a retrospective cohort study of consecutive patients with anterior circulation large vessel occlusions who underwent EVT from 2015 to 2021. Patients with Thrombolysis In Cerebral Infarction (TICI) 2b reperfusion and follow-up imaging were identified. Baseline characteristics, procedural details, and imaging findings were reviewed. Primary outcome was categorized according to the occurrence of infarction at the territory of distal embolus on follow-up diffusion-weighted imaging MRI.

RESULTS

Of 156 subjects, 97 (62%) had at least one infarction in the territories at risk. Hypertension was significantly more prevalent in the infarct group (83% vs 53%, P=0.001). General anesthesia was more commonly used in the infarct group (60% vs 43%, P=0.037). The median number of distal emboli and diameter of the occluded vessel were similar. After adjusting for confounders, hypertension (aOR 4.73, 95% CI 1.81 to 13.25, P=0.002), higher blood glucose (aOR 1.01, 95% CI 1.00 to 1.03, P=0.023), and general anesthesia (aOR 2.75, 95% CI 1.15 to 6.84, P=0.025) were independently associated with infarction. The presence of angiographic leptomeningeal collaterals predicted tissue survival (aOR 0.13, 95% CI 0.05 to 0.33, P<0.001). 90-day modified Rankin scale (mRS) scores were worse for the infarction patients (mRS 0-2: infarct, 39% vs 55%, P=0.046).

CONCLUSIONS

Nearly 40% of patients with TICI 2b had no tissue infarction in the territory of a distal embolus. The association of infarction with hypertension and general anesthesia suggests late or post-procedural blood pressure management could be a modifiable factor. Patients with poor leptomeningeal collaterals or hyperglycemia may benefit from further attempts at revascularization.

Management of intracranial arterial stenosis during mechanical thrombectomy: Survey of neuro-interventionalists

BACKGROUND

The optimal management of emergent large vessel occlusion due to underlying intracranial stenosis (intracranial stenosis related large vessel occlusion) remains unknown. The primary aim of this survey analysis was to measure variation in the clinical management of intracranial stenosis related large vessel occlusion during mechanical thrombectomy.

METHODS

A survey was designed using a web-based survey-building platform and distributed via the Society of NeuroInterventional Surgery (SNIS) and the Society of Vascular and Interventional Neurology (SVIN) websites for a response. Predictors of respondents' level of comfortability stenting were estimated using a binomial logistic regression model.

RESULTS

We received 105 responses to the survey. Most respondents (54.3%) practiced at an academic Stroke Center. Nearly half of the respondents (49%) had been practicing for 5 or more years independently after fellowship. An average of 54 mechanical thrombectomies were performed by each respondent annually. There was variation in the definition of intracranial stenosis related large vessel occlusion, number of passes performed before pursuing rescue stenting, as well as intra and post-procedural antiplatelet management. Of respondents, 58% felt rescue stenting was very risky, and 55.7% agreed that there was equipoise regarding emergent angioplasty and/or stenting versus medical therapy for intracranial stenosis related large vessel occlusion. Respondents who encountered intracranial stenosis related large vessel occlusion more frequently thought that rescue stenting was less risky.

CONCLUSION

There is notable variability in the diagnosis and management of intracranial stenosis related large vessel occlusion during mechanical thrombectomy. While most respondents felt rescue stenting was risky, the majority believed the benefit could outweigh the risk. The majority of respondents agreed that equipoise exists regarding the management of intracranial stenosis related large vessel occlusion, highlighting the need for clinical trials in this rare patient population.

Large Vessel Occlusion Stroke due to Intracranial Atherosclerotic Disease: Identification, Medical and Interventional Treatment, and Outcomes

Large vessel occlusion stroke due to underlying intracranial atherosclerotic disease (ICAD-LVO) is prevalent in 10 to 30% of LVOs depending on patient factors such as vascular risk factors, race and ethnicity, and age. Patients with ICAD-LVO derive similar functional outcome benefit from endovascular thrombectomy as other mechanisms of LVO, but up to half of ICAD-LVO patients reocclude after revascularization. Therefore, early identification and treatment planning for ICAD-LVO are important given the unique considerations before, during, and after endovascular thrombectomy. In this review of ICAD-LVO, we propose a multistep approach to ICAD-LVO identification, pretreatment and endovascular thrombectomy considerations, adjunctive medications, and medical management. There have been no large-scale randomized controlled trials dedicated to studying ICAD-LVO, therefore this review focuses on observational studies.

Computed Tomography Perfusion-Based Prediction of Core Infarct and Tissue at Risk: Can Artificial Intelligence Help Reduce Radiation Exposure?

BACKGROUND AND PURPOSE

We explored the feasibility of automated, arterial input function independent, vendor neutral prediction of core infarct, and penumbral tissue using complete and partial computed tomographic perfusion data sets through neural networks.

METHODS

Using retrospective computed tomographic perfusion data from 57 patients, split as training/validation (60%/40%), we developed and validated separate 2-dimensional U-net models for cerebral blood flow (CBF) and time to maximum (Tmax) maps calculation to predict core infarct and tissue at risk, respectively. Once trained, the full sets of 28 input images were sequentially reduced to equitemporal 14, 10, and 7 time points. The averaged structural similarity index measure between the model-derived images and ground truth perfusion maps was compared. Volumes for core infarct and Tmax were compared using the Pearson correlation coefficient.

RESULTS

Both CBF and Tmax maps derived using 28 and 14 time points had similar structural similarity index measure (0.80-0.81; P>0.05) when compared with ground truth images. The Pearson correlation for the CBF and Tmax volumes derived from the model using 28-tp with ground truth volumes derived from the RAPID software was 0.69 for CBF and 0.74 for Tmax. The predicted maps were fully concordant in terms of laterality to the commercial perfusion maps. The mean Dice scores were 0.54 for the core infarct and 0.63 for the hypoperfusion maps.

CONCLUSIONS

Artificial intelligence model-derived volumes show good correlation with RAPID-derived volumes for CBF and Tmax. Within the constraints of a small sample size, the perfusion map quality is similar when using 14-tp instead of 28-tp. Our findings provide proof of concept that vendor neutral artificial intelligence models for computed tomographic perfusion processing using complete or partial image data sets appear feasible. The model accuracy could be further optimized using larger data sets.

Safety and Feasibility of Symptomatic Carotid Artery Stent-Assisted Revascularization within 48 Hours after Symptoms Onset

OBJECTIVE

We aimed to evaluate the safety and feasibility of carotid artery stenting (CAS) performed in the hyperacute period.

METHODS

We analyzed a retrospective database of CAS patients from our center. We included patients with symptomatic isolated ipsilateral extracranial carotid stenosis and acute tandem occlusions who underwent CAS. Hyperacute CAS (HCAS) and acute CAS (ACAS) groups were defined as CAS within 48 hours and >48 hours to 14 days from symptoms onset, respectively. The primary outcome was a composite of any stroke, myocardial infarction, or death at 3 months of follow-up. Secondary outcomes were periprocedural complications and restenosis or occlusion rates.

RESULTS

We included 97 patients, 39 with HCAS and 58 with ACAS. There was no significant difference between groups for the primary outcome (HCAS 3.3% vs. ACAS 6.1%; p = 1). There were no differences in the rate of perioperative complications between groups although a trend was observed (HCAS 15.3% vs. ACAS 3.4%; p = .057). The rate of restenosis or occlusion between groups (HCAS 8.1% vs. ACAS 9,1%; log-rank test p = .8) was similar with a median time of follow-up of 13.7 months.

CONCLUSION

Based on this study, CAS may be feasible in the hyperacute period. However, there are potential higher rates of perioperative complications in the hyperacute group, primarily occurring in MT patients with acute tandem occlusion. A larger multicenter study may be needed to further corroborate our findings.

Onyx embolization for dural arteriovenous fistulas: a multi-institutional study

BACKGROUND

Although the liquid embolic agent, Onyx, is often the preferred embolic treatment for cerebral dural arteriovenous fistulas (DAVFs), there have only been a limited number of single-center studies to evaluate its performance.

OBJECTIVE

To carry out a multicenter study to determine the predictors of complications, obliteration, and functional outcomes associated with primary Onyx embolization of DAVFs.

METHODS

From the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR) database, we identified patients who were treated for DAVF with Onyx-only embolization as the primary treatment between 2000 and 2013. Obliteration rate after initial embolization was determined based on the final angiographic run. Factors predictive of complete obliteration, complications, and functional independence were evaluated with multivariate logistic regression models.

RESULTS

A total 146 patients with DAVFs were primarily embolized with Onyx. Mean follow-up was 29 months (range 0-129 months). Complete obliteration was achieved in 80 (55%) patients after initial embolization. Major cerebral complications occurred in six patients (4.1%). At last follow-up, 84% patients were functionally independent. Presence of flow symptoms, age over 65, presence of an occipital artery feeder, and preprocedural home anticoagulation use were predictive of non-obliteration. The transverse-sigmoid sinus junction location was associated with fewer complications, whereas the tentorial location was predictive of poor functional outcomes.

CONCLUSIONS

In this multicenter study, we report satisfactory performance of Onyx as a primary DAVF embolic agent. The tentorium remains a more challenging location for DAVF embolization, whereas DAVFs located at the transverse-sigmoid sinus junction are associated with fewer complications.

Safety and efficacy of symptomatic carotid artery stenting performed in an emergency setting

INTRODUCTION

Carotid artery stenting (CAS) has increasingly emerged as an alternative strategy to carotid endarterectomy in the treatment of patients with symptomatic carotid stenosis. Optimal timing for CAS after symptoms onset remains unclear. We aimed to evaluate the safety and efficacy of CAS when performed in an emergency setting.

PATIENTS AND METHODS

We performed a retrospective analysis of CAS patients admitted to our CSC with symptomatic extracranial carotid occlusion or significant stenosis from January 2014-September 2019. Emergency CAS was defined as CAS performed during the same hospitalization from TIA/stroke onset, whereas elective CAS as CAS performed on a subsequent admission. The primary outcome was defined as the occurrence of any stroke, myocardial infarction, or death related to the procedure at 3 months of follow-up. Secondary outcomes included periprocedural complications and the rate of restenosis/occlusion at follow-up. Logistic regression and survival analyses were used to compare outcomes and restenosis at follow-up.

RESULTS

We identified 75 emergency and 104 elective CAS patients. Emergency CAS patients had significantly higher rates of ipsilateral carotid occlusion (17% vs. 2%, p < 0.001) and use of general anesthesia (19% vs. 4%, p = 0.001) than elective CAS. There were no significant differences between emergency and elective CAS in the primary (5.7% vs. 1%, p = 0.161) and secondary (9% vs. 4.8%, p = 0.232) outcomes. We did not find differences in the rate of restenosis/occlusion (7% vs. 11.6%; log-rank test p = 0.3) at a median of 13 months follow-up.

CONCLUSION

In our study, emergency CAS in symptomatic patients might have a similar safety and efficacy profile to elective CAS at 3 months and long-term follow-up.

Detection and Quantification of Symptomatic Atherosclerotic Plaques With High-Resolution Imaging in Cryptogenic Stroke

BACKGROUND AND PURPOSE

High-resolution vessel wall imaging (HR-VWI) is a powerful tool in diagnosing intracranial vasculopathies not detected on routine imaging. We hypothesized that 7T HR-VWI may detect the presence of atherosclerotic plaques in patients with intracranial atherosclerosis disease initially misdiagnosed as cryptogenic strokes.

METHODS

Patients diagnosed as cryptogenic stroke but suspected of having an intracranial arteriopathy by routine imaging were prospectively imaged with HR-VWI. If intracranial atherosclerotic plaques were identified, they were classified as culprit or nonculprit based on the likelihood of causing the index stroke. Plaque characteristics, such as contrast enhancement, degree of stenosis, and morphology, were analyzed. Contrast enhancement was determined objectively after normalization with the pituitary stalk. A cutoff value for plaque-to-pituitary stalk contrast enhancement ratio (CR) was determined for optimal prediction of the presence of a culprit plaque. A revised stroke cause was adjudicated based on clinical and HR-VWI findings.

RESULTS

A total of 344 cryptogenic strokes were analyzed, and 38 eligible patients were imaged with 7T HR-VWI. Intracranial atherosclerosis disease was adjudicated as the final stroke cause in 25 patients. A total of 153 intracranial plaques in 374 arterial segments were identified. Culprit plaques (n=36) had higher CR and had concentric morphology when compared with nonculprit plaques (P≤0.001). CR ≥53 had 78% sensitivity for detecting culprit plaques and a 90% negative predictive value. CR ≥53 (P=0.008), stenosis ≥50% (P<0.001), and concentric morphology (P=0.030) were independent predictors of culprit plaques.

CONCLUSIONS

7T HR-VWI allows identification of underlying intracranial atherosclerosis disease in a subset of stroke patients with suspected underlying vasculopathy but otherwise classified as cryptogenic. Plaque analysis in this population demonstrated that culprit plaques had more contrast enhancement (CR ≥53), caused a higher degree of stenosis, and had a concentric morphology.

Combined Transradial and Transfemoral Approach With Ostial Vertebral Balloon Protection for the Treatment of Patients With Subclavian Steal Syndrome

Background: Patients with an obstructive subclavian artery (SA) may exhibit symptoms of vertebrobasilar insufficiency known as subclavian steal syndrome (SSS). Endovascular treatment with stent assisted percutaneous transluminal angioplasty (SAPTA) demonstrates significantly lower percentage of intraoperative and postoperative complications in comparison with open surgery. There is a 1–5% risk of distal intracranial embolization through the ipsilateral vertebral artery (VA) during SAPTA.

Objective: To assess the safety and feasibility of a novel technique for distal embolic protection using balloon catheters during SA revascularization with a dual transfemoral and transradial access.

Methods: We describe a case series of patients with SSS who underwent SAPTA due to severe stenosis or occlusion of the SA using a combined anterograde/retrograde approach. Transfemoral access to SA was obtained using large bore guide sheaths. Ipsilateral transradial access was obtained using intermediate bore catheters. A Scepter XC balloon catheter was introduced through the transradial intermediate catheter into the ipsilateral VA at the ostium during SAPTA for distal embolic protection.

Results: A total of eight patients with SSS underwent subclavian SAPTA. Four patients had the combined anterograde/retrograde approach. Successful revascularization was achieved in three of them. It was difficult to create a channel in the fourth unsuccessful case due to heavily calcified plaque burden. No peri-operative ischemic events were identified. On follow-up, we demonstrated patency of the stents with resolution of symptoms and without any adverse events.

Conclusion: Subclavian stenting using a combined transradial and transfemoral access with compliant balloon catheters at the vertebral ostium for prevention of distal emboli may represent an alternative therapeutic approach for the treatment of SA stenosis and occlusions.

Increased contrast enhancement of the parent vessel of unruptured intracranial aneurysms in 7T MR imaging

BACKGROUND

Inflammation of the arterial wall may lead to aneurysm formation. The presence of aneurysm enhancement on high-resolution vessel wall imaging (HR-VWI) is a marker of wall inflammation and instability. We aim to determine if there is any association between increased contrast enhancement in the aneurysmal wall and its parent artery.

METHODS

Patients with unruptured intracranial aneurysms (UIAs) prospectively underwent 7T HR-VWI. Regions of interest were selected manually and with a semi-automated protocol based on gradient algorithms of intensity patterns. Mean signal intensities in pre- and post-contrast T1-weighted sequences were adjusted to the enhancement of the pituitary stalk and then subtracted to objectively determine: circumferential aneurysmal wall enhancement (CAWE); parent vessel enhancement (PVE); and reference vessel enhancement (RVE). PVE was assessed over regions located 3- and 5 mm from the aneurysm's neck. RVE was assessed in arteries located in a different vascular territory.

RESULTS

Twenty-five UIAs were analyzed. There was a significant moderate correlation between CAWE and 5 mm PVE (Pearson R=0.52, P=0.008), whereas no correlation was found between CAWE and RVE (Pearson R=0.20, P=0.33). A stronger correlation was found between CAWE and 3 mm PVE (Pearson R=0.78, P<0.001). Intra-class correlation analysis demonstrated good reliability between measurements obtained using semi-automated and manual segmentation (ICC coefficient=0.790, 95% CI 0.58 to 0.90).

CONCLUSION

Parent arteries exhibit higher contrast enhancement in regions closer to the aneurysm's neck, especially in aneurysms≥7 mm. A localized inflammatory/vasculopathic process in the wall of the parent artery may lead to aneurysm formation and growth.

Comparing the outcomes of two independent computed tomography perfusion softwares and their impact on therapeutic decisions in acute ischemic stroke

BACKGROUND

To compare the computed tomography perfusion (CTP) outcomes derived from two commercial CTP processing software and evaluate their concordance in terms of eligibility for mechanical thrombectomy (MT) in acute ischemic stroke (AIS), based on DEFUSE III criteria.

METHODS

A total of 118 patients (62 patients in the MT group and 56 patients in the non-MT (NMT) group) were included. Volumetric perfusion outputs were compared between Syngo.via (package A) and RAPID (package B). Influence on proceeding or not-proceeding with MT was based on DEFUSE III imaging eligibility criteria.

RESULTS

Median core infarct/hypoperfusion volumes were 12.3/126 mL in the MT group and 7.7/29.3 ml in the NMT group with package A and 10.5/138 mL and 1.9/24.5 mL with package B, respectively. In the MT group (n=62), concordant perfusion results in terms of patient triage were noted in all but two cases. Of these, one patient would not have qualified (low ASPECTS), while the other qualified based on package A results. For the NMT group (n=56), there was discordance in terms of MT eligibility in seven cases. However, none of these patients qualified for MT based on DEFUSE III criteria.

CONCLUSIONS

Both perfusion softwares showed high concordance in correctly triaging patients in the MT versus NMT groups (110/118, 93.2%), which further improved when all DEFUSE III imaging criteria were considered (117/118, 99.1%). The core/hypoperfusion volumes in the NMT group and core infarct volumes in the MT groups were comparable. The hypoperfusion volumes in the MT group varied slightly but did not affect triage between groups.

Retrospective, dual-centre review of imaging findings in neurosarcoidosis at presentation: prevalence and imaging sub-types

AIM

To assess the prevalence of various imaging manifestations in neurosarcoidosis (NS) patients at presentation and to explore if specific imaging findings may cluster in different sub-groups.

MATERIALS AND METHODS

A retrospective, dual-institution, systematic imaging review was undertaken of the magnetic resonance imaging (MRI) findings in 100 consecutive NS patients who presented over a 15-year period. Clustering analysis (k-mode) was performed to evaluate co-occurrence of imaging findings.

RESULTS

Non-enhancing white matter (NEWM) lesions were the most common imaging abnormality (56%), followed by leptomeningeal (47%) and pachymeningeal (32%) involvement. Other common manifestations included cranial nerve involvement (30%), parenchymal granulomas (27%), hypothalamic-pituitary-adrenal axis involvement (26%), and hydrocephalus (14%). Additionally, a higher prevalence of perivascular enhancement (23%), cerebrovascular events (including ischaemic and haemorrhagic events; 17%), and ependymal involvement (20%) were noted than recognised previously. Additional k-mode analysis was performed to explore underlying disease sub-clusters. This was evaluated for clusters varying between two though five (k=2-5). For k=4, the analysis revealed that the imaging findings may possibly be divided into disease sub-sets of four groups, each with varying distribution of imaging manifestations and clinical manifestations.

CONCLUSION

Overall, NEWM lesions and meningeal involvement are the most common imaging manifestations of NS. The prevalence of perivascular enhancement, cerebrovascular events, and ependymal involvement is likely higher than reported previously. Additionally, different imaging findings in NS may cluster together and imaging subtypes in NS possibly exist.

Abstract 55: Comparison of Sequential Multi-Detector CT and Cone-Beam CT Perfusion Maps in 54 Subjects With an Acute Ischemic Stroke

Introduction: Time from diagnostic imaging to groin puncture highly correlates with outcome and often accounts for delays between hospital arrival and EVT. Our study comparing image quality and information content of MDCTP and CBCTP provides feasibility data for selected AIS patients to go straight to the angio-suite for comprehensive imaging and treatment.

Methods: AIS patients eligible for EVT underwent MDCTP, then a CBCTP study on arrival in angio-suite. Of 939 admitted June 2017-April 2019, 226 (24%) received EVT. Of these 54 (35%) were enrolled to receive additional CBCTP imaging. Inability to obtain consent and co-morbidities were major causes for non-enrollment. Times from the start of MDCTP to angio-suite and from angio-suite arrival to first arterial image were recorded. Acquired CBCTP data were reconstructed and processed with an in-house toolbox. MDCTP and CBCTP data were matched for slice thickness and angulation and were processed using RAPID CTP (iSchemaView, Inc.). The rCBF, rCBV, MTT, tMAX maps were randomized to generate 3 unique evaluation sets. 3 neuroradiologists scored diagnostic image quality, artifacts, mismatch pattern detection and EVT indication using 5-point Likert scales. Stroke laterality was compared with the clinical standard for diagnostic accuracy.

Results: Accuracies for stroke diagnosis are 97% [95%, 97%] with MDCTP and 92% [90%, 95%] with CBCTP. Cohen’s Kappa between observers is 0.90 for MDCTP-based diagnosis and 0.89 for CBCTP-based diagnosis. Scores of CBCTP to make the stroke diagnosis, detect mismatch pattern, and make treatment decision were non-inferior to corresponding scores for MDCTP (alpha=0.05) within 10% of the whole score range. Subjective scores of MDCTP for image quality and artifacts were slightly superior to those of CBCTP (1.8 vs. 2.3, p<0.01).

Conclusions: In this study, a direct to angio-suite workflow provided non-inferior perfusion imaging for AIS patient triage while saving nearly one hour per patient.

Abstract TP122: Peri-Procedural Stroke or Death in Stenting of Symptomatic Severe Intracranial Stenosis: A Post-Hoc Analysis of the SAMMPRIS Trial

Background and Purpose: There is limited data on predictors of 30-day stroke or death in patients with symptomatic intracranial atherosclerosis (sICAS) undergoing stenting. We aim to determine these predictors.

Methods: This is a post-hoc analysis SAMMPRIS including patients who underwent angioplasty/stenting. We determined associations between patient-specific, lesion-specific, and procedure-specific variables, and FDA-approved indications and the primary outcome (stroke or death at 30 days) using logistic regression analyses.

Results: We identified 213 patients; 30 patients (14.1%) met the primary outcome. The odds of stroke or death was higher with non-smokers vs. smokers (adjusted OR 4.46, 95% CI 1.79-11.1) and increasing lesion length in millimeters (adjusted OR 1.20, 95% CI 1.02-1.39). These had modest predictive value: absence of smoking history (sensitivity=66.7% and specificity=65.4%) and lesion length (Area Under Curve=0.606). Furthermore, event rates were not significantly different between patients with and without the FDA approved indication for stenting (15.9% vs. 12%, p = 0.437).

Conclusion: In SAMMPRIS patients who underwent angioplasty/stenting, neither clinical and neuroimaging variables nor the FDA indication for stenting reliably predicted the primary outcome. Further work in identifying reliable biomarkers of stroke/death in patients with sICAS is needed before considering new clinical trials of stenting.

Abstract TP76: Quantitative Comparison of Multidetector CT and Cone-Beam CT Perfusion Maps in Large Vessel Occlusion Stroke Patients Undergoing Mechanical Thrombectomy

Cerebral perfusion evaluation using CT or MR perfusion is the gold standard modality to select large vessel occlusion (LVO) stroke patients presenting >6 hours from symptom onset. The availability of cone beam C-arm CT perfusion (CBCTP) in angiography suites could reduce time to endovascular revascularization. We aimed to evaluate the reliability of using CBCTP when compared to multidetector CT perfusion (MDCTP). In this prospective, single-arm, interventional study, 14 LVO anterior circulation thrombectomy patients underwent both a 128 slice MDCTP in the ED and a CBCTP <30 minutes apart prior to groin puncture. CBCTP was acquired using a prototype acquisition mode enabling 10 consecutive C-Arm rotations with nearly continuous data acquisition. A total of 60 cc of contrast layered with 60 cc of saline were injected covering arterial inflow, parenchymal phase and venous outflow. Image data was reconstructed into CBF, CBV, MTT and TTP maps. Three types of measurements were used to compare modalities. In measurement 1, 6 circular regions of interest (ROI) (400mm 2 ) were placed in the anterior arterial territory. In measurement 2, circular ROIs were placed in the ASPECTS regions (cortical 300mm 2 , subcortical 200mm 2 ). In measurement 3, a ROI was drawn around the entire affected area. All ROIs were placed in the basal ganglia and supraganglionic level of both brain sides. Rates (unaffected/affected area) between MDCTP and CBCTP were compared for all sequences. The intraclass correlation coefficient (ICC) was calculated using a single rater, consistency, two-way random-effects model. Measurement 1 found a moderate degree of agreement between MDCTP and CBCTP in CBF, CBV, MTT and TTP rates with ICCs of 0.58 (CI 0.42 - 0.69), 0.65 (CI 0.53 - 0.74), 0.77 (CI 0.68 - 0.83) and 0.52 (CI 0.35 - 0.65). In measurement 2, moderate agreement was found in CBF, CBV and MTT rates; with ICCs of 0.51 (CI 0.32 - 0.65), 0.57 (CI 0.4 - 0.69) and 0.62 (CI 0.47 - 0.73). The results of measurement 3 found an excellent (ICC=0.95, CI 0.88 - 0.98), good (ICC=0.83, CI 0.62 - 0.9) and moderate (ICC=0.7, CI 0.34 - 0.87), degree of agreement in the CBV, MTT and CBF rates, respectively. These results demonstrate promising accuracy of CBCTP in the evaluating ischemic tissue in patient presenting with LVO acute stroke.

Abstract 125: Observation versus Treatment for Low-Grade Intracranial Dural Arteriovenous Fistulas: A Multicenter Matched Cohort Study

Background and Purpose: Given the benign natural history of intracranial low-grade dural arteriovenous fistulas (dAVFs), their routine treatment remains controversial. The aim of this study is to compare the outcomes of low-grade dAVF treatment to conservative management.

Methods: We performed a retrospective review of dAVF patients derived from 12 institutions participating in the Consortium for Dural Arteriovenous Fistula Outcomes Research (CONDOR). Patients with low-grade (Borden I) dAVFs were included and categorized into treatment and observation cohorts. Primary outcome was defined as modified Rankin Scale (mRS) score at final follow-up. Secondary outcomes were rates of excellent (mRS 0-1) and good (mRS 0-2) functional outcomes, symptomatic improvement, mortality, and obliteration at final follow-up.

Results: The treatment and observation cohorts comprised 230 and 112 patients, respectively. At last follow up, no difference in primary or secondary outcomes was observed between the two cohorts, with the exception of obliteration, which was higher in the treatment cohort (79.3% vs. 28.2%, p<0.001; Table 1). The two cohorts were then matched in a 1:1 ratio, resulting in 64 patients in each matched cohort. No difference in primary or secondary outcomes was observed between the matched cohorts, with the exception of obliteration, which was higher in the matched treatment cohort (75.4% vs. 28.6%, p<0.001; Table 2). Subgroup analysis of symptomatic patients demonstrated higher obliteration rate in the treatment cohort, but no difference in primary or other secondary outcomes were found.

Conclusions: Low-grade dAVF treatment was not associated with increased functional disability compared to conservative management. Although higher obliteration rates were achieved in the treatment cohort, rates of symptomatic improvement were similar between the two cohorts. This study did not provide evidence to support the routine treatment of low-grade dAVFs.

Abstract WP6: Safety of Acute Carotid Stenting Treatment in Acute Symptomatic Patients

Carotid stenting (CAS) has been shown to be equivalent to carotid endarterectomy in symptomatic patients; however its optimal timing remains unclear. In this study, we aim to evaluate the safety of CAS when performed within the first 48 hours of symptom onset. We performed a retrospective analysis of a prospectively collected database of consecutive CAS patients admitted to our comprehensive stroke center with TIA/stroke and ipsilateral symptomatic carotid stenosis >50% from 2014 to 2019. Medical records were retrospectively reviewed for demographic, clinical and procedural data and outcomes. Acute and delayed treatment were defined as ≤48 and >48 hours from last known well (LKW) respectively. The primary endpoint was procedure-related major complications (stroke with NIHSS increase of ≥4, myocardial infarction, parenchymal hemorrhage type 2 or death) ≤30 days after CAS. Secondary endpoints were procedure-related minor neurological (stroke with NIHSS increase of <4 and reperfusion injury) and non-neurological (groin puncture hematoma, acute anemia and arrhythmia) complications. Functional outcome was assessed by discharge and 90 days mRS, dichotomized as good (0-2) and bad (3-6). A total of 72 patients were included in the analysis, 36 in each group. There was no difference in age, NIHSS at presentation, gender, incidence of TIA as presentation or percentage of TPA received. The acute group differed significantly from the delayed group in number of thrombectomies (36.1% vs. 5.6%, p=0.001) and median time from LKW to CAS (15.9 hours vs. 88.0 hours, p<0.001). There were significantly more carotid occlusions in the acute group when compared to the delayed group (37.8% vs. 2.2, p<0.0001). Overall, the acute group did not show significant difference from the delayed group in major (2.8% vs. 5.6%, p=1.0), minor neurological (13.9% vs. 2.8%, p=0.09) and minor non-neurological complication rates (13.9% vs. 8.3%, p=0.7). Rates of good outcomes were not significantly different between the two groups at discharge (52.8% vs. 50%) or 90 days (75% vs. 63%). CAS can be performed safely in acute symptomatic carotid stenosis patients within the first 48 hours from symptom onset.

Abstract WP72: Low kV Computed Tomography Cerebral Angiogram Using Third-Generation Reconstruction Algorithm Provides Significantly Improved Image Quality With Lower Contrast and Radiation Exposure

Introduction/Aim: We aimed to determine if CTA imaging using third generation reconstruction algorithm and lower contrast dose-low kVp technique (LD-CTA) was comparable to regular contrast dose CTA at 120 kVp using a sinogram affirmed iterative reconstruction algorithm (ND-CTA).

Methods: Retrospective imaging review of 100 consecutive patients (50 each in LD- and ND-CTA groups). Two readers independently assessed the subjective image quality across multiple vascular segments on a Likert-like scale. Contrast- and signal-to-noise ratios (CNR/ SNR) were compared for the mid-M1-MCA vessels bilaterally and the mid-basilar artery. Fisher’s exact test was used to compare subjective image quality. Interclass correlation coefficient (ICC) was calculated for the SNR/CNR values. Finally differences in contrast dose, CT-dose index (CTDI) and dose length product (DLP) were compared using Mann-Whitney U test.

Results: Both observers showed excellent correlation in subjective image quality (mean percentage agreement of 95.2% (84-100%) for group-1 versus 89.2% (82%-98%) for group-2). The subjective scores were not statistically different in the anterior circulation but showed significantly better image quality for the basilar artery. LD-CTA group showed significantly better SNR and CNR (p < 0.0001) for both MCA vessels and the basilar artery. ICC showed moderate correlation (0.51-0.63) between the observers. Student paired t-test did not show any significant difference between the observers. LD-CTA group also used lower contrast (49 cc versus 103 cc in ND-CTA) and had lower radiation exposure (DLP/ CTDI for both groups 268.3/12.42 vs 519.5/ 25.15, both < 0.0001).

Conclusion: Next-generation reconstruction algorithm and low-Kv scanning significantly improved image quality on cerebral CTA images despite lower contrast dose, and in addition, have lower radiation exposure.

Common Data Elements for Radiological Imaging of Patients with Subarachnoid Hemorrhage: Proposal of a Multidisciplinary Research Group

INTRODUCTION

Lack of homogeneous definitions for imaging data and consensus on their relevance in the setting of subarachnoid hemorrhage and unruptured intracranial aneurysms lead to a difficulty of data pooling and lack of robust data. The aim of the National Institute of Health/National Institute of Neurological Disorders and Stroke, Unruptured Intracranial Aneurysm (UIA) and Subarachnoid Hemorrhage (SAH) Common Data Elements (CDE) Project was to standardize data elements to ultimately facilitate data pooling and establish a more robust data quality in future neurovascular research on UIA and SAH.

METHODS

For the subcommittee 'Radiological imaging of SAH,' international cerebrovascular specialists with imaging expertise in the setting of SAH were selected by the steering committee. CDEs were developed after reviewing the literature on neuroradiology and already existing CDEs for other neurological diseases. For prioritization, the CDEs were classified into 'Core,' 'Supplemental-Highly Recommended,' 'Supplemental' and 'Exploratory.'

RESULTS

The subcommittee compiled 136 CDEs, 100 out of which were derived from previously established CDEs on ischemic stroke and 36 were newly created. The CDEs were assigned to four main categories (several CDEs were assigned to more than one category): 'Parenchymal imaging' with 42 CDEs, 'Angiography' with 49 CDEs, 'Perfusion imaging' with 20 CDEs, and 'Transcranial doppler' with 55 CDEs. The CDEs were classified into core, supplemental highly recommended, supplemental and exploratory elements. The core CDEs were imaging modality, imaging modality type, imaging modality vessel, angiography type, vessel angiography arterial anatomic site and imaging vessel angiography arterial result.

CONCLUSIONS

The CDEs were established based on the current literature and consensus across cerebrovascular specialists. The use of these CDEs will facilitate standardization and aggregation of imaging data in the setting of SAH. However, the CDEs may require reevaluation and periodic adjustment based on current research and improved imaging quality and novel modalities.

Peri-procedural stroke or death in stenting of symptomatic severe intracranial stenosis

BACKGROUND AND PURPOSE

There are limited data on predictors of 30-day stroke or death in patients with symptomatic intracranial atherosclerosis (sICAS) undergoing stenting. We aim to determine the factors associated with stroke or death at 30 days in the stenting arm of the SAMMPRIS trial.

METHODS

This is a post-hoc analysis of the SAMMPRIS trial including patients who underwent angioplasty/stenting. We compared patient-specific variables, lesion-specific variables, procedure-specific variables, and FDA-approved indications between patients with and without the primary outcome (stroke or death at 30 days). Logistic regression analyses were performed to evaluate associations with the primary outcome.

RESULTS

We identified 213 patients, 30 of whom (14.1%) met the primary outcome. Smoking status and lesion length were associated with the primary outcome: the odds of stroke or death for non-smokers versus smokers (adjusted OR 4.46, 95% CI 1.79 to 11.1, p=0.001) and for increasing lesion length in millimeters (adjusted OR 1.20, 95% CI 1.02 to 1.39, p=0.029). These had a modest predictive value: absence of smoking history (sensitivity 66.7%, specificity 65.4%) and lesion length (area under curve 0.606). Furthermore, event rates were not significantly different between patients with and without the FDA-approved indication for stenting (15.9% vs 12%, p=0.437).

CONCLUSION

In SAMMPRIS patients who underwent angioplasty/stenting, neither clinical and neuroimaging variables nor the FDA indication for stenting reliably predicted the primary outcome. Further work in identifying reliable biomarkers of stroke/death in patients with sICAS is needed before considering new clinical trials of stenting.

TRIAL REGISTRATION NUMBER

SAMMPRIS NCT00576693; Results.

Safety and efficacy of the use of large bore intermediate suction catheters alone or in combination for the treatment of acute cerebral venous sinus thrombosis: A multicenter experience

BACKGROUND AND PURPOSE

Systemic anticoagulation is the standard treatment for cerebral venous sinus thrombosis (CVST). Several endovascular techniques have been described as salvage therapy for anticoagulation refractory CVST cases. We aim to evaluate the safety and feasibility of endovascular aspiration thrombectomy using the new generation, large bore suction catheters alone or in combination with stentriever devices for the treatment of CVST.

METHODS

We collected data on 16 consecutive patients with CVST who received endovascular aspiration thrombectomy at three large academic centers. Second generation reperfusion catheters were used as a large bore suction catheter and advanced to the affected sinus using a coaxial technique. Suction was performed using pump suction. At times, a stentriever was used as an anchor to facilitate advancing the suction catheter and to increase thrombectomy capabilities.

RESULTS

Median decade of age was the 50s and nine patients were women. Fifty percent of the patients had multiple sinuses involved. All patients received systemic anticoagulation prior to endovascular aspiration thrombectomy. The most common reason to pursue endovascular aspiration thrombectomy in CVST patients was deterioration of initial clinical status (10/16). The mean time from admission to endovascular aspiration thrombectomy was 1.5 days (range 0-6 days). Good recanalization was obtained in all patients. There were no major peri-procedural complications. Most patients were discharged to either home or a rehabilitation facility.

CONCLUSION

Endovascular aspiration treatment using large bore suction catheters for CVST is a safe and feasible approach for the treatment of anticoagulation refractory CVST. Heterogeneity of the clinical and radiological presentation requires further investigation to optimize patient selection before evaluating the efficacy of this technique in larger prospective studies.

Stroke mechanisms and outcomes of isolated symptomatic basilar artery stenosis

Background

While diffuse atherosclerotic disease affecting the posterior circulation has been described extensively, the prevalence, natural history and angiographic characteristics of isolated symptomatic basilar artery stenosis (ISBAS) remain unknown.

Methods

We reviewed our prospective institutional database to identify patients with ≥50% symptomatic basilar artery (BA) stenosis without significant atherosclerotic burden in the vertebral or posterior cerebral arteries. Stroke mechanism, collateral circulation, and degree and length of stenosis were analysed. The primary outcome was time from index event to new transient ischaemic attack (TIA), acute ischaemic stroke (AIS) or death. Other outcome variables included modified Rankin Scale (mRS) score on discharge and last follow-up.

Results

Of 6369 patients with AIS/TIA, 91 (1.43%) had ISBAS. Seventy-three (80.2%) patients presented with AIS and 18 (19.8%) with TIA. Twenty-nine (31.9%) were women and the median age was 66.8±13.6 years. The mean follow-up time was 2.7 years. The most common stroke mechanism was artery-to-artery thromboembolism (45.2%), followed by perforator occlusion (28.7%) and flow-dependent/hypoperfusion (15.1%). The percentage of stenosis was lower in patients who had favourable outcome compared with those with mRS 3-6 on discharge (78.3±14.3 vs 86.9±14.5, p=0.007). Kaplan-Meier curves showed higher recurrence/death rates in patients with ≥80% stenosis, mid-basilar location and poor collateral circulation. Approximately 13% of patients with ISBAS presented with complete BA occlusion.

Conclusion

ISBAS is an uncommon (1.43%) cause of TIA and AIS. Men in their 60s are mostly affected, and artery-to-artery embolism is the most common stroke mechanism. Mid-basilar location, ≥80% stenosis and poor collateral circulation are important factors associated with worse prognosis.

Achieving comparable perfusion results across vendors. The next step in standardizing stroke care: a technical report

Background

The role of mechanical thrombectomy in acute ischemic stroke (AIS) has been further expanded by recent trials which relied on the results of CT perfusion (CTP) imaging. However, CTP parameters for ischemia and infarct can vary significantly across different vendors.

Methods

We compared the outcomes of the Siemens CTP software against the clinically validated RAPID software in 45 consecutive patients with suspected AIS. Both perfusion softwares initially processed images using vendor defined parameters for hypoperfusion and non-viable tissue. The software thresholds on the Siemens software were decrementally altered to see if concordant results between softwares could be attained.

Results

At baseline settings, the mean values for core infarct and hypoperfusion were different (mean of 30/69 mL, respectively, for RAPID and 49/77 mL for Siemens). However, reducing the threshold values for the later software showed a concordance of values at a relative cerebral blood flow <20%, with resulting core infarct and hypoperfusion volumes at 31/69 mL, respectively, for the Siemens software. A Wilcoxon paired test showed no significant difference between the calculated core infarct and hypoperfusion values, both for the entire population as well as for the subgroup of patients with large vessel occlusion.

Conclusion

Equivalent CTP results between vendor softwares may be attainable by altering the thresholds for hypoperfused and non-viable tissue, despite differences in acquisition techniques, post-processing, and scanners.

Abstract WP394: Impact of MRI/A versus CTA/P versus Direct Angiosuite Triage Protocols in Stroke Care Performance and Outcome of Transferred Patients for Endovascular Thrombectomy

Introduction: Transferred thrombectomy patients face additional time delays that might worsen outcome when compared to direct admission. In 2015, we moved from an MRI/A to a CTA/P protocol to decrease treatment times in transferred patients. In 2017, we initiated a direct admission to angiosuite (DAN) strategy. Herein, we aim to describe procedural and clinical outcomes in transfer patients with acute LVO stroke triaged by these protocols.

Method: We reviewed demographics, clot location, and treatment times for all thrombectomies from 2013 to June 2018. Primary outcome was MRS at 90 days. Secondary outcomes were door to groin time, difference between NIHSS at admission and discharge (ΔNIHSS). Distributions are analyzed with Wilcoxon Rank, chi-squared and Fisher’s Exact Tests. Logistic regression is used to evaluate MRS and mortality outcomes and adjusted for clot location, admission NIHSS and tPA use.

Results: The analysis includes 178 patients: 25 MRI/A, 130 CT/A/P, and 23 DAN. The groups significantly differ by tPA (16% vs 4% vs 13%, p=0.03), NIHSS at arrival (median 16 vs 17 vs 21, continuous p=0.03) and clot location (ICA 8% vs 20% vs 35%, BA 24% vs 10% vs 26%, p=0.01) for MRI, CT, and DAN respectively. There is significant reduction in median door to groin time between all groups (MRI 170 min., CT 84 min., DAN 16 min., p<0.001). The median ΔNIHSS is significantly different between CT and MRI (10 vs 4, p=0.01) and borderline significant between DAN and MRI (11 vs 4, p=0.07). There is a trend towards decrease disability (MRS 4-5) for DAN patients when compared to MRI at both discharge (OR=0.847, 95% CI 0.18, 4.10) and 90 days (OR=0.38, 95% CI 0.07, 2.10). There is significant increased risk of mortality when comparing DAN and MRI at 90 days (p=0.02).

Conclusion: DAN is feasible with faster procedural times and may have clinical benefit in select patients. RCTs are needed to assess the advantages and harm of decreasing imaging in benefit of time.

Abstract TP339: Off Hours Presentation is Not Associated With Poor Functional Outcomes or Faster Recanalization Times in Stroke Patients Receiving Mechanical Thrombectomy in a Large Volume Comprehensive Stroke Center

Background: Faster revascularization times are associated with better functional outcome in patients undergoing thrombectomy. We aim to evaluate the impact of time of day presentation on thrombectomy metrics and its association with long-term functional outcome in an IR equipped OR setting.

Methods: We retrospective reviewed all stroke patients who received mechanical thrombectomy between December 2012 and December 2017 at our CSC from our prospectively collected database. Work hours were defined by official OR work hours (Monday-Friday 7 AM and 5PM) and after hours as between 5 PM and 7 AM during weekdays and weekends as well as official hospital holidays. Collected data included baseline demographics, admission NIHSS, receipt of tPA, and location of occlusion. Primary outcomes were delta NIHSS between admission and discharge and 90-day modified Rankin Scale (mRS). Secondary outcomes included door to groin time and revascularization rate (TICI2b and 3). Multivariable logistic and Wilcoxon Rank test were performed to compare groups.

Results: A total of 78 (38%) patients underwent mechanical thrombectomy during work hours and 125 (62%) during after-hours. There were more females in the after-hours group (55% vs 40%, P=0.046). There was no difference in mean age (66.8 vs 68.1, P=0.457), race (93% whites in both group) and median admission NIHSS (17 in both groups). Median door to groin time was 85 minutes during work hours vs. 94 minutes during after-hours (P=0.93). There was no difference in revascularization rate (70% vs 76%, P=0.67), delta NIHSS (2.9 vs 5.7, P=0.173) or long-term functional outcome (43% vs 53%, P=0.121) between after-hours vs work hours respectively.

Conclusion: Studies suggest that after hours delay could impact functional outcomes on stroke patients undergoing thrombectomy. In-house 24/7 Anesthesia and IR tech services might improve metrics and mitigate this effect.

Abstract WP59: A Clot Burden Score Predicts Functional Outcome and Neurological Complications After Cerebral Venous Sinus Thrombosis

Background and purpose: Involvement of deep venous structures is associated with worse outcomes in patients with cerebral venous sinus thrombosis (CVST); however, the impact of clot burden has not been studied. The aim of this study was to assess the value of a novel quantitative clot burden score as an independent predictor of clinical outcomes.

Methods: We retrospectively reviewed all patients admitted to University of Iowa Health Care with CVST between 2004-2014. All patients received standard of care medical management per AHA/ASA recommendations. The degree of the thrombosis was categorized in admission MR venograms as (partial=1 vs. complete occlusion=2). Clot burden scores were computed as the sum of the thrombosis degree in the following vessels: cerebral veins (cortical veins, internal cerebral, vein of Rosenthal, vein of Galen) and cerebral sinuses (superior sagittal, inferior sagittal, straight, torcula, transverse/sigmoid). The primary outcome was modified Rankin Scale (mRS) at discharge. Secondary outcomes included hemorrhage, infarction, and cerebral edema. Multiple regressions were conducted to examine effects of clot burden scores on each of the four outcomes.

Results: 115 patients met inclusion criteria, 76 women, and mean age 42. Thrombosis in cerebral veins area was noted in 58(50%), clot burden score Median=4, IQR=2; while 108(96%) had thrombosis in the cerebral sinuses area, Median=4, IQR=5. Clot burden in cerebral veins (p=.005) but not in cerebral sinuses, was associated with worse discharge mRS, r= .22. This effect remained significant when adjusting for age and gender (p=.002), but not when adjusting for complications including ICH, infarct, edema. Importantly, higher clot burden score in the cerebral veins predicted ICH (OR=1.73, p<.001), infarct size (OR=1.66, p<.001), and edema (OR=1.71, p<.001).

Conclusion: Quantitative clot burden measurement of the cerebral veins conveys additional prediction on outcomes of CVST. Our findings suggest that the worse clinical outcomes associated with clot burden in the cerebral veins may be mediated by ICH, infarct size, and/or edema. The structural differences between the cerebral veins and sinuses may play a role in the variability in clinical outcomes among patients with CVST.

Abstract TP130: Recurrent Hemispheric Stroke Syndromes in Symptomatic Atherosclerotic Internal Carotid Artery Occlusions: The COSS Trial

Background: There are limited data on the baseline characteristics and clinical outcomes of patients who have recurrent hemispheric syndromes in the territory of symptomatic atherosclerotic internal carotid artery occlusion (AICAO).

Methods: Baseline characteristics and clinical outcomes were compared between patients with (rHEM+) and without (rHEM-) recurrent ipsilateral hemispheric syndromes at the time of randomization into the Carotid Occlusion Surgery Study (COSS) based on local investigator clinical impression.

Results: Of 195 participants who were randomized, 100 (51%) were rHEM+ (50 in each study arm) and 95 were rHEM-(48 nonsurgical, 47 surgical). Baseline characteristics between rHEM+ and rHEM- participants were similar except that rHEM+ participants were more likely to have had a previous stroke prior to entry event (59% vs 22%, p < 0.001) and to have had TIA vs stroke as the entry event (61% vs 20%, p<0.001). All primary endpoints were ipsilateral ischemic strokes. There were no statistically significant differences in the primary endpoint between nonsurgical and surgical participants with rHEM+ (26.3% vs 22.4%, p=0.660) or rHEM- (18.9% vs 19.5%%, p=0.943). For secondary endpoints based on stroke severity and/or death, no important differences were noted between nonsurgical and surgical participants for the rHEMI+ and rHEMI- subgroups (all p > 0.10). For the nonsurgical participants, there was no statistically significant difference in the primary endpoint for those rHEM+ vs rHEM- (26.3% vs 18.9%, p=.410)

Conclusion: Patients with recurrent hemispheric stroke syndromes enrolled in the COSS trial were more likely to have had previous stroke and to have TIAs as the entry event to randomization. Given the lack of surgical treatment benefit seen in these patients, early aggressive risk factor measures should be prioritized to reduce recurrent strokes, including blood pressure control which was associated with a 70% reduction in stroke in the nonsurgical group in COSS ( Neurology 2014; 82:1027-1032).

Abstract WP47: Quantitative Analysis of Hemorrhage and Infarct Volume for Predicting Outcome in Cerebral Venous Sinus Thrombosis

Background and purpose: Intracerebral hemorrhage (ICH) and venous infarction are known complications that independently predict poor outcome in patients with cerebral venous sinus thrombosis (CVST). We aimed to study the utility of precise quantification of volumes of venous infarction and ICH using digitalized images in refining our prediction of discharge outcome.

Methods: We retrospectively reviewed all patients with CVST admitted to University of Iowa Health Care between 2004-2014. All patients received standard of care management per available AHA/ASA recommendations. Scans were analyzed using Carestream Vue PACS software. Gradient Echo (GRE) MRI sequence was used to calculate ICH volume. When MRI was not available CT was used. Diffusion Weighted Imaging (DWI) MRI sequence was used to calculate infarction volume. Volume scorer was blinded to the clinical outcomes. Univariate and multivariate analyses were conducted. A p value ≤ 0.05 was set as statistically significant.

Results: 115 patients met inclusion criteria, 76 women, mean age 42. A total of 30 (26%) had venous infarction, 34 (30%) had ICH. The median volumes were 8 cc (SD=27) for ICH and 14 cc (SD= 35) for infarction. Both ICH and infarction volumes were significantly higher among those with a poor functional outcome (mRS=3-6) [Mdn=16 cc, SD=32 for ICH; Mdn=33 cc, SD=46 for infarction] than those with good outcome [Mdn=5 cc, SD=7 for ICH; Mdn=7 cc, SD=162 for infarction], p= .029 and p=.027 respectively. The correlation between ICH volume and mRS was r=.43, p=.012 and the corresponding correlation for infarction volume was r=.62, p=.002. Regressions testing the effects of ICH and infarction volumes on discharge mRS showed that both significantly contributed (p<.001 & p=.004 respectively). These effects remained significant when controlling for the effects of age, gender, presence of deep infarct, and altered mental status at presentation (p=.001 and p=.013 respectively).

Conclusion: Quantitative measurement of Infarction and ICH volumes on admission leads to a more accurate prediction of outcome at discharge in CVST patients. Its combination with clinical variables might signify an additional prognostication tool for identification of high risk patients refractory to standard therapy.

Abstract WP63: Global Cerebral Edema is Associated With Worse Outcomes in Patients With Cerebral Venous Sinus Thrombosis

Background and Purpose: Obstruction of venous drainage may lead to venous hypertension, edema, infarction or intracerebral hemorrhage (ICH) in patients with cerebral venous thrombosis (CVST). While the presence of ICH and infarction are associated with worse outcomes, the independent effect of edema remains unknown. We aimed to evaluate the impact of the characteristics of brain edema on functional outcomes as measured by the modified Rankin Scale (mRS) at discharge.

Methods: We retrospectively reviewed all patients who presented to the University of Iowa Health Care with CVST between 2004-2014. All patients received standard of care management per available AHA/ASA recommendations. Edema was categorized as focal vasogenic, focal cytotoxic or global cerebral edema (GCE). Vasogenic edema was described as hyperintensity on FLAIR MRI sequences around the location of venous clot while cytotoxic edema was noted when hyperintensities were visualized around the location of ICH/ venous infarction on FLAIR or DWI respectively. GCE was scored when bilateral finger-like extensions into gray white junction and effacement of gyri/sulci were seen on CT scans as described by Claassen et al. Edema scorer was blinded to outcome measures. Multiple regressions were conducted on mRS outcome to test hypotheses of interest. A p value ≤ 0.05 was set as statistically significant.

Results: 115 patients met inclusion criteria, 76 women, mean age 42. A total of 30(26%) had venous infarction, 34(30%)ICH , 57(50%) had cerebral edema(20% vasogenic, 35% cytotoxic and 32% GCE). The three edema types together explained 22% variance in discharge mRS (p<.001). The effect of GCE remained significant (p=.001) when adjusting for age, presence/absence of ICH and infarct. The 95%CIs for discharge mRS among those with GCE [2.89-4.17] compared to those without GCE [1.44-2.12]. Vasogenic and cytotoxic edema did not contribute significantly to prediction in multivariate analyses.

Conclusions: Characterization of early cerebral edema might contribute to a better prognostication of high risk patients after CVTS. GCE in particular forecast an unfavorable outcome. Further understanding of its pathogenesis may represent a new therapeutic window for refractory patients to standard therapies.

Acute Effect of Intravenous Sildenafil on Cerebral Blood Flow in Patients with Vasospasm After Subarachnoid Hemorrhage

BACKGROUND

The phosphodiesterase-5 inhibitor sildenafil has been shown to attenuate delayed cerebral ischemia (DCI) and improve neurologic function in experimental subarachnoid hemorrhage (SAH). We recently demonstrated that it could improve cerebral vasospasm (CVS) in humans after SAH. However, successful therapies for DCI must also restore cerebral blood flow (CBF) and/or autoregulatory capacity. In this study, we tested the effects of sildenafil on CBF in SAH patients at-risk for DCI.

METHODS

Six subjects with angiographically confirmed CVS received 30-mg of intravenous sildenafil (mean 9 ± 2 days after aneurysmal SAH). Each underwent (15)O-PET imaging to measure global and regional CBF at baseline and post-sildenafil.

RESULTS

Mean arterial pressure declined by 10 mm Hg on average post-sildenafil (8 %, p = 0.01), while ICP was unchanged. There was no change in global CBF (mean 34.5 ± 7 ml/100g/min at baseline vs. 33.9 ± 8.0 ml/100g/min post-sildenafil, p = 0.84). The proportion of brain regions with low CBF (<25 ml/100g/min) was also unchanged after sildenafil infusion.

CONCLUSIONS

Infusion of sildenafil does not lead to a change in global or regional perfusion despite a significant reduction in cerebral perfusion pressure. While this could reflect the ineffectiveness of sildenafil-induced proximal vasodilatation to alter brain perfusion, it also suggests that cerebral autoregulatory function was preserved in this group. Future studies should assess whether sildenafil can restore or enhance autoregulation after SAH.

Blunt Cerebrovascular Injuries: Advances in Screening, Imaging, and Management Trends

Blunt cerebrovascular injury is a relatively uncommon but sometimes life-threatening injury, particularly in patients presenting with ischemic symptoms in that vascular territory. The decision to pursue vascular imaging (generally CT angiography) is based on clinical and imaging findings. Several grading scales or screening criteria have been developed to guide the decision to pursue vascular imaging, as well as to recommend different treatment options for various injuries. The data supporting many of these guidelines and options are limited however. The purpose of this article is to review and compare these scales and criteria and the data supporting clinical efficacy and to make recommendations for future research in this area.

Abstract TP302: Improvement of Endovascular Stroke Care Performance After Transition From MRI/A to an CTP-based Imaging Protocol

Background and Purpose: The 2015 Focused Update for the Acute Ischemic Stroke Guidelines emphasized the importance of rapid patient selection, optimization of endovascular procedures and organizations of systems of care. Our institution, which has been performing endovascular procedures using a rapid MRI/MRA imaging protocol, transitioned in 2015 to a CT/CTA/CTP imaging protocol. The goal of the study is to evaluate the impact of the transition to CTP on endovascular performance, as measured by door to imaging time and door to skin puncture, and the improvement of the neurological deficit measured by NIHSS difference at admission and discharge.

Methods: All endovascular procedures performed from January 2014 to May 2016 were reviewed from our prospective database. CT perfusion was performed with injection of 40 cc iodinated contrast and 40 seconds acquisition time. The CTA images were generated from the CT perfusion. Demographics, endovascular performance and discharged status were obtained. Continuous variables were assessed for normality by the Kolmogorov-Smirnov test. Non-parametric data were reported as median and analysed using the Kruskal-Wallis test or Wilcoxon Ranks test.

Results: A total of 91 thrombectomies were initially identified. The median age was 65 (IQR:53-77) with 52% males. 78% were anterior circulation strokes (ACS). Although the overall number of stroke admission remained relatively stable, the proportion of thrombectomies duplicated every year (23/1003 in 2014 vs. 38/1159 in 2015 vs. 32/632 until May 2016). Door to advance imaging median time (52 mins vs 24 mins vs.25 minutes; p=0.023) and door to skin puncture median time (130 mins vs. 100 mins vs. 81 mins; p=0.007) demonstrated significant differences in the ACS. A significant improvement in NIHSS at discharge was noted after implementation of the protocol (18 to 8; p=0.001 in 2015 and 17.5 to 8 in 2016; p=0.006 vs. 14 to 9 in 2014; p=0.777).

Conclusion: Transition to CT-based imaging protocols was associated with improvement in the delivery of endovascular acute care in a Comprehensive Center used to acute MRI imaging despite the logistic challenges and lack of familiarity with the new technique. Transition to CT-based imaging is a reasonable approach to improve endovascular care.

Same-Day Discharge After Treatment with the Pipeline Embolization Device Using Monitored Anesthesia Care

OBJECTIVE

The Pipeline Embolization Device (PED) has been used and shown to be safe under monitored anesthesia care (MAC). We present the results of the first study, to our knowledge, assessing the safety and feasibility of same-day discharge in patients undergoing treatment with the PED, using MAC.

METHODS

A total of 130 patients with 143 cerebral aneurysms (CAs) were identified. Patients were treated under MAC with the PED. All of the patients were counseled preoperatively about the elective nature of the procedure and the same-day discharge.

RESULTS

The mean age of the participants was 60.7 ± 12.12 years. Men constituted 27.69% (36/130) of the population. The number of procedures was 138. All of our patients elected to return home the same day, whereas only 6.15% (8/130) of them changed their mind in the postoperative setting and elected to stay overnight out of convenience (late discharge, patient preference, or living alone at home). Overall discharge home on the same day occurred after 90.6% of procedures (125/138) and in 91.53% (119/130) of the patients. All same-day discharges took place within 4-6 hours after the procedures. The rate of major complications was 0.75% (1/134). The mortality rate was 0%.

CONCLUSIONS

PED treatment under MAC is feasible and safe. This has brought forth an era of outpatient treatment of CAs where patients are discharged home 6 hours after the procedure.

Acute Stroke Imaging Research Roadmap III Imaging Selection and Outcomes in Acute Stroke Reperfusion Clinical Trials: Consensus Recommendations and Further Research Priorities

BACKGROUND AND PURPOSE

The Stroke Imaging Research (STIR) group, the Imaging Working Group of StrokeNet, the American Society of Neuroradiology, and the Foundation of the American Society of Neuroradiology sponsored an imaging session and workshop during the Stroke Treatment Academy Industry Roundtable (STAIR) IX on October 5 to 6, 2015 in Washington, DC. The purpose of this roadmap was to focus on the role of imaging in future research and clinical trials.

METHODS

This forum brought together stroke neurologists, neuroradiologists, neuroimaging research scientists, members of the National Institute of Neurological Disorders and Stroke (NINDS), industry representatives, and members of the US Food and Drug Administration to discuss STIR priorities in the light of an unprecedented series of positive acute stroke endovascular therapy clinical trials.

RESULTS

The imaging session summarized and compared the imaging components of the recent positive endovascular trials and proposed opportunities for pooled analyses. The imaging workshop developed consensus recommendations for optimal imaging methods for the acquisition and analysis of core, mismatch, and collaterals across multiple modalities, and also a standardized approach for measuring the final infarct volume in prospective clinical trials.

CONCLUSIONS

Recent positive acute stroke endovascular clinical trials have demonstrated the added value of neurovascular imaging. The optimal imaging profile for endovascular treatment includes large vessel occlusion, smaller core, good collaterals, and large penumbra. However, equivalent definitions for the imaging profile parameters across modalities are needed, and a standardization effort is warranted, potentially leveraging the pooled data resulting from the recent positive endovascular trials.

Final results of the US humanitarian device exemption study of the low-profile visualized intraluminal support (LVIS) device

Introduction

The low-profile visualized intraluminal support (LVIS) device is a new, braided, intracranial microstent designed for stent-assisted coiling.

Objective

To present the results of a single-arm, prospective, multicenter trial of the LVIS for treatment of wide-necked intracranial aneurysms.

Methods

31 patients with unruptured, wide-necked (neck ≥4 mm or dome:neck ratio ≤2) intracranial aneurysms were treated with the LVIS device and bare platinum coils at six US centers (investigational device exemption G110014). Clinical follow-up was conducted at 30 days and 6 months. Angiographic follow-up was performed at 6 months. The primary safety endpoint was any major stroke or death within 30 days or major ipsilateral stroke or neurological death within 6 months. ‘Probable benefit’ was defined as ≥90% angiographic occlusion at 6 months. An independent core laboratory adjudicated the angiographic results. An independent clinical events committee adjudicated the clinical endpoints.

Results

Average aneurysm size was 7.2 mm (SD 3.8) and average neck width was 4.6 mm (SD 1.8). 68% of patients had a dome:neck ratio ≤2. LVIS placement was technically successful in 29/31 patients (93.5%). No primary safety endpoints occurred during the study (0%). No patient had a higher modified Rankin Score at 6 months than at baseline. 26/28 (92.9%) treated aneurysms with 6-month angiographic follow-up demonstrated ≥90% angiographic occlusion. 21/28 (75%) were completely occluded at follow-up.

Conclusions

The LVIS device facilitated the coil embolization of wide-necked intracranial aneurysms with high rates of technical success, an excellent safety profile, and very high rates of complete and near-complete occlusion at follow-up.

Trial registration number

NCT01541254.