Utilizing RNA sequencing to identify gene expression markers of stroke-causing thrombi origin: A pilot study

INTRODUCTION

Stroke embolic source have an unknown origin in 30-40% of cases. Mechanical thrombectomy for acute large vessel occlusion stroke has provided us with a method to directly retrieve the thrombi from patients for analysis. By collecting stroke-causing thrombi from known sources, we can then use high-throughput RNA sequencing (RNAseq) technology to directly measure the gene expression signatures of these clots. This may allow us to identify genetic markers to predict the cause of cryptogenic embolism.

METHODS

This is a prospective study in which RNAseq was used to analyze cerebral thrombi retrieved by mechanical thrombectomy devices in acute ischemic stroke patients. Samples were separated into two groups based on known stroke thrombus etiology, including Carotid group (patients with ipsilateral >70% carotid stenosis) and Atrial fibrillation (AF) group (patients with atrial fibrillation). Gene expression was compared by RNAseq analysis between the groups.

RESULTS

From October 2016 to September 2017, 8 thrombi (4 in Carotid group, 4 in Afib group) were included in this study. There were 131 genes that were significantly up- or down-regulated between the two groups defined as a false discovery rate ≤ 0.05 and a fold change ≥ 2. Twenty-six genes were selected as candidate gene biomarkers based on the criteria in the methods section. Candidate genes HSPA1B, which encodes a heatshock protein, and GPRC5B, which encodes a G-protein, showed the greatest fold differences in expression between the two groups.

CONCLUSION

This study has shown that RNA sequencing of acute ischemic stroke thrombi is feasible and indentified potential novel biomarkers for identifying stroke-causing thrombi origin, especially in cryptogenic stroke.

Optimal technique for canine mesenchymal stem cells labeling with novel SPIO, MIRB™: for MRI detection of transplanted stem cells canine stroke model

BACKGROUND

Cell-based therapy has emerged as a promising avenue for post-stroke recovery. A significant challenge lies in tracking the distribution and engraftment of transplanted cells within the target cerebral tissue. To address this, we turn to the potential of Brain MRI detection of mesenchymal stem cells (MSCs), achieved by labeling these cells with superparamagnetic iron oxide (SPIO). This is the first report of a technique to label canine MSCs using a commercially available SPIO, Molday ION Rhodamine B (MIRB), to optimize both viability and labeling efficacy for transplantation purposes."

METHOD

Canine MSCs were incubated with addition of different MIRB concentration from 0, 10, 20, 30 μg Fe/ml. The cellular uptake of MIRB was confirmed through the analysis of fluorescent images and flow cytometry. The morphological characteristics of MSCs were assessed via microscopic visualization. Cellular viability was evaluated using both a cellometer and flow cytometry.

RESULT

Fluorescent microscopic images of all MIRB incubated MSCs groups show >70% labeled cells with homogenous signal intensity. Notably, the morphology of MSCs remained unaltered in the 10 μg Fe/ml group compared to the control group. Furthermore, among the labeled groups, the 10 μg Fe/ml concentration exhibited the highest viability when assessed using two different flow cytometry methods (95.3%, p < 0.05).

CONCLUSION

This study successfully labels canine MSCs with MIRB. The optimal concentration of 10 μg Fe/ml demonstrates optimal viability, labeling efficacy, and preserved cellular morphology.

Transradial Access Failures During Neuroangiography for Patients With Moyamoya

BACKGROUND

Despite studies continuing to demonstrate the utility of transradial access (TRA) in neuroangiography, minimal data exist regarding predictors of TRA failure. Furthermore, although many patients with moyamoya disease/syndrome will require life-long angiographic evaluation, even less has been reported on the usage of TRA in this population.

OBJECTIVE

To perform a matched analysis at our high-volume moyamoya center to determine predictors of TRA failure in these patients.

METHODS

A total of 636 patients undergoing TRA for neuroangiography were identified from 2018 to 2020. Demographic and angiographic characteristics including radial artery spasm (RAS), radial anomalies, and access site conversion were compared between patients with moyamoya and the rest of the cohort. A 4:1 matched analysis, based on age and sex, was also performed to eliminate confounding variables.

RESULTS

Patients with moyamoya were younger (40 vs 57 years, P < .0001), had smaller radial diameters (1.9 vs 2.6 mm, P < .0001), more commonly had a high brachial bifurcation (25.9% vs 8.5%, P = .008), more frequently experienced clinically significant RAS (40% vs 8.4%, P < .0001), and more often required access site conversion (26.7% vs 7.8%, P = .002). Increasing age was associated with less TRA failures in patients with moyamoya (odds ratio = 0.918) but more failures in the rest of the cohort (odds ratio = 1.034). In the matched analysis, patients with moyamoya continued to experience more radial anomalies, RAS, and access site conversions.

CONCLUSION

Patients with moyamoya, when controlling for age and sex, have higher rates of TRA failure during neuroangiography. Increasing age in Moyamoya is inversely correlated with TRA failures suggesting that younger patients with moyamoya are at higher risk of extracranial arteriopathy.

Mission thrombectomy 2020 (MT2020+) surveys of Caribbean stroke services: A call for action in our region

Stroke is the leading cause of death and adult-onset disability in the Caribbean region. Despite the tremendous advances in acute stroke care in the past 25 years, treatment in the Caribbean lags stroke standards of care. Mission Thrombectomy 2020+ (MT2020+) is a metrics based global campaign focused on increasing access to organized stroke care and mechanical thrombectomy. We conducted two consecutive online surveys across the MT2020+ Caribbean Region assessing access to thrombolytics, mechanical thrombectomy and stroke centers. The first survey - Mechanical Thrombectomy Access-Caribbean sub-study, allowed a comparison between global services and those in the MT2020+ Caribbean region. This survey provided a snapshot of the current state of stroke centers worldwide and confirmed lower available stroke resources in the MT2020+ Caribbean Region which has one certified stroke center, and 9 mechanical thrombectomy capable centers. The second survey - MT2020+ Caribbean Region infrastructure survey - was designed to determine the availability of stroke resources that are key components of stroke care in participating hospitals. Key infrastructural components such as 24/7 computerized tomographic scanners, access to thrombolytic therapy and access to mechanical thrombectomy capable centers were scarce. There were low volumes of mechanical thrombectomy performed in the Caribbean compared to other countries around the world. Limited resources and inadequate stroke infrastructure remains a major challenge in the Caribbean. We advocate for governmental support and investment, public and private partnerships and legislation to increase access and availability to acute stroke treatments to allow for equal access to care for all Caribbean citizens.

Abstract HUP4: Svin Mt2020 + Global Mechanical Thrombectomy Access Barrier Score

Introduction: Mechanical thrombectomy (MT) is a highly safe and effective standard of care for acute ischemic strokes with large vessel occlusion. However, timely access to MT is extremely limited on a global scale, with vast disparities in access between countries. MT2020+, a global non-profit initiative of SVIN, aimed to create a semi-quantitative global MT access barrier score (MTABS) to objectively measure the barriers impeding the implementation of treatment worldwide.

Methods: Four independent investigators performed an in-depth systematic literature review using the peer review of electronic search strategies. Barriers to access were identified and categorized into 3 groups: information and diagnostic, physical, and financial. An international expert panel was created and scored each attribute using a modified Delphi process with the assistance of consultants from the University of Calgary W21C. A 1-9-point scale was used, with 1 being not at all important and 9 being extremely important. A meeting was held for the attributes that require deliberation. After an agreement, a list of attributes for access was elaborated. Next, a ranking of importance and individual weighting was done. We assigned a presence of or lack of an attribute a numerical value (1 for yes, 0 for no) and multiply by its weight to determine a final score.

Results: After an initial screening of 2864 abstracts, 121 studies were included in the final systematic review. A total of 34 possible attributes that are barriers to access were identified. After the modified Delphi process, 26 individual attributes were selected. The MTABS was made with possible results from 0-62 points, with higher scores meaning higher barriers to access to MT.

Conclusions: The global MTABS represents the first tool to quantify barriers to MT access worldwide. Its implementation will objectively measure the magnitude and identify key barriers to guide regional public health interventions to improve MT workflow and access.

Abstract TMP46: Large Vessel Occlusion Stroke Knowledge And Clinical Training In Emergency Medical Service Personnel In The United States

Background: Stroke education of emergency medical service (EMS) personnel improves stroke recognition, prenotification, and thrombolytic delivery. Prehospital identification of large vessel occlusion (LVO) stroke may facilitate the creation of a regional bypass protocol and improvement of intrahospital and interhospital workflows. However, the current status of EMS personnel’s knowledge of LVO, their stroke severity assessment training, and preferences in educational methods have not been studied. We conducted an EMS survey across the United States.

Methods: The Society of Vascular and Interventional Neurology (SVIN) in collaboration with EMS-World created an online questionnaire distributed to all subscribers of EMS-World involved in pre-hospital work. It included 12 multiple-choice questions to test participants on LVO knowledge, stroke center certification levels, prior LVO education, and preferences on educational content delivery.

Results: The survey email was opened by 1830 subscribers out of whom 1107 (60%) completed the survey across 50 states in the United States. Respondents identified themselves as paramedics/EMTs (91.4%), ground critical care (5.7%) and flight crew (2.9%). The number of stroke patients that survey participants transported in the past year was <10 for 618 (55.8%), 10 to 25 for 332 (30%), and >25 (14.2%). Two hundred eighty-five (25.8%) participants answered both LVO knowledge questions correctly and 379 (34.2%) answered one correctly. Only 128 (11.6%) correctly identified all types of centers with thrombectomy capability. Although 877 (79.2%) were familiar with at least one stroke severity scale, 376 (34%) denied receiving training to perform them. Five sixty-seven (51.2%) respondents preferred in-person training for LVO training and 429 (38.8%) an online training program. About half of all respondents (535,48%) picked 'lack of standardized LVO training' as the greatest hurdle to pre-hospital LVO management.

Conclusion: EMS providers in the United States reported inadequate LVO training and demonstrated gaps in knowledge of LVO, stroke severity scales, and stroke center levels. Systematic efforts to enhance and standardize the educational content and delivery of LVO education are urgently needed.

Cohort study on the differential expression of inflammatory and angiogenic factors in thrombi, cerebral and peripheral plasma following acute large vessel occlusion stroke

Inflammation plays an important role in the pathogenesis of stroke. The differential expression of inflammatory and angiogenic factors in thrombi and plasma remain undefined. In this observational cohort study, we evaluated angiogenic factors and inflammatory cytokines, in cerebral thrombi, local cerebral plasma (CP), and peripheral plasma (PP) in patients with acute ischemic stroke. Protein analysis of thrombi, CP and PP were used to measure angiogenic and inflammatory proteins using electrochemiluminescence. Our data indicate that VEGF-A, VEGF-C, bFGF, IL-4, IL-13, IL-1β, IL-2, IL-8, IL-16, IL-6 and IL-12p70 were higher in the thrombi of acute ischemic stroke patients than in the CP and PP of stroke patients. Moreover, the protein levels of GM-CSF were lower in the PP than in the CP and the clot. Moreover, VEGF-D, Flt-1, PIGF, TIE-2, IL-5, TNF-β, IL-15, IL-12/IL-23p40, IFN-γ and IL-17A were higher in PP and CP than in thrombi. Our results show that cytokines mediating the inflammatory response and proteins involved in angiogenesis are differentially expressed in thrombi within the cerebral and peripheral circulations. These data highlight the importance of identifying new biomarkers in different compartments of the circulatory system and in thrombi that may be used for the diagnosis and treatment of stroke patients.

Radial Long Sheath Angioplasty for Proximal Severe Flow Limiting Radial Artery Spasm Utilizing the Dotter Technique

BACKGROUND

Although studies continue to demonstrate the advantages of transradial access (TRA) for neurointerventions, radial artery spasm (RAS) remains a frequent cause of TRA failure. Dotter initially described a technique to dilate areas of peripheral vascular stenosis by advancing sequentially larger catheters across the lesion over a wire. We present our institutional experience performing a modified Dotter technique utilizing long radial sheaths to dilate areas of proximal flow limiting RAS.

OBJECTIVE

To review the use of the Dotter technique for alleviating RAS in patients undergoing TRA for neurointerventions.

METHODS

A retrospective review of all patients undergoing TRA for neurointerventions at our institution from 2018-2020 was performed to identify patients with proximal flow limiting RAS. In identified patients, a modified Dotter technique was employed to dilate the stenosis. Demographic and periprocedural data were assessed to identify any adverse outcomes.

RESULTS

Four patients with severe proximal flow limiting RAS were identified. In each case, a hydrophilic long radial sheath and vascular dilator were sequentially advanced through the stenosis. In all cases, repeat angiography demonstrated improvement of the spasm and final radial angiograms demonstrated persistent improvement in caliber and regularity of the vessel. Each procedure was also completed via TRA with no periprocedural complications.

CONCLUSIONS

Our modified Dotter technique is effective in bypassing areas of severe proximal flow limiting RAS thus obviating the need for access site conversion. Additional studies are warranted to understand the implication of the angioplasty-like effects seen within the radial artery following removal of the long radial sheaths.

Radial Artery Access for Cerebral Angiography: 2-Dimensional Operative Video

A number of studies have demonstrated that the radial artery is a safer access site than the femoral artery for endovascular procedures.1-4 In the prospective randomized studies comparing transradial and transfemoral approaches for cardiac procedures, there was a 60% reduction in access site complications as well as significant decreases in all-cause mortality with the transradial approach as compared to transfemoral, which has led to the adoption of a radial first strategy.5-7 Neurointerventional studies have demonstrated similar safety benefits as well as improved patient preference.8-14 In this video, a patient presented with an unruptured anterior communicating artery aneurysm and consented to a transradial artery diagnostic cerebral angiogram. This technical video demonstrates the key preprocedural preparation, room setup, patient positioning, steps for radial artery, and distal radial artery puncture and sheath placement. Distal transradial artery access is our preferred approach for diagnostic cerebral angiography because of an improved safety profile and procedural ergonomics. In cases in which a larger radial artery is advantageous such as for neurointerventions requiring larger systems, a standard transradial approach may be performed.9 In this video, a full 6-vessel cerebral angiogram is performed, followed by our arteriotomy closure technique using our standard equipment including a 10-cm 5 French Glidesheath Slender (Terumo, Japan), 100-cm hydrophilic coated 5 French Simmons 1 catheter (Merit OEM), 0.035 hydrophilic coated guidewire, and SafeGuard closure device (Merit, Salt Lake City, Utah).

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.

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

Background

During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study’s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines.

Methods

We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March–31 May 2020. The prior 1-year control period (1 March–31 May 2019) was obtained to account for seasonal variation.

Findings

There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI −24.3% to −20.7%, p<0.0001). Embolisation of ruptured aneurysms declined with 1170–1035 procedures, respectively, representing an 11.5% (95%CI −13.5% to −9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI −28.0% to −22.1%, p<0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile.

Interpretation

There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction.

New Class of Radially Adjustable Stentrievers for Acute Ischemic Stroke: Primary Results of the Multicenter TIGER Trial

Supplemental Digital Content is available in the text.

Background and Purpose:

The Tigertriever is a novel, radially adjustable, fully visible, stentriever that permits the operator to align radial expansion with target vessel diameters. This multicenter trial compared the Tigertriever’s effectiveness and safety compared with established stent retrievers.

Methods:

Single arm, prospective, multicenter trial comparing the Tigertriever to efficacy and safety performance goals derived from outcomes in 6 recent pivotal studies evaluating the Solitaire and Trevo stent-retriever devices with a lead-in and a main-study phase. Patients were enrolled if they had acute ischemic stroke with National Institutes of Health Stroke Scale score ≥8 due to large vessel occlusion within 8 hours of onset. The primary efficacy end point was successful reperfusion, defined as core laboratory-adjudicated modified Thrombolysis in Cerebral Ischemia score 2b-3 within 3 passes of the Tigertriever. The primary safety end point was a composite of 90-day all-cause mortality and symptomatic intracranial hemorrhage. Secondary efficacy end points included 3-month good clinical outcome (modified Rankin Scale score 0–2) and first-pass successful reperfusion.

Results:

Between May 2018 and March 2020, 160 patients (43 lead-in, 117 main phase) at 17 centers were enrolled and treated with the Tigertriever. The primary efficacy end point was achieved in 84.6% in the main-study phase group compared with the 63.4% performance goal and the 73.4% historical rate (noninferiority P<0.0001; superiority P<0.01). The first pass successful reperfusion rate was 57.8%. After all interventions, successful reperfusion (modified Thrombolysis in Cerebral Ischemia score ≥2b) was achieved in 95.7% and excellent reperfusion (modified Thrombolysis in Cerebral Ischemia score 2c-3) in 71.8%. The primary safety composite end point rate of mortality and symptomatic intracranial hemorrhage was 18.1% compared with the 30.4% performance goal and the 20.4% historical rate (noninferiority P=0.004; superiority P=0.57). Good clinical outcome was achieved in 58% at 90 days.

Conclusions:

The Tigertriever device was shown to be highly effective and safe compared with Trevo and Solitaire devices to remove thrombus in patients with large-vessel occlusive stroke eligible for mechanical thrombectomy.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03474549.

Hyperacute Management of Ischemic Strokes: JACC Focus Seminar

Acute ischemic stroke is the leading cause of disability and among the leading causes of mortality worldwide. Intravenous tissue plasminogen activator has been a cornerstone for treatment of acute ischemic stroke for more than 20 years; however, its use is limited due to a narrow therapeutic window, several contraindications, and low efficacy to recanalize the artery in large vessel occlusion. Recently, the addition of endovascular mechanical thrombectomy of large artery occlusion has revolutionized the stroke treatment for most disabling strokes. The paper reviews updates to the thrombolytic treatment as well as catheter-based treatment, and results from recent trials in the selection of patients in an extended time window using perfusion imaging.

Trends in incidence and epidemiologic characteristics of cerebral venous thrombosis in the United States

OBJECTIVE

To test the hypothesis that race-, age-, and sex-specific incidence of cerebral venous thrombosis (CVT) has increased in the United States over the last decade.

METHODS

In this retrospective cohort study, validated ICD codes were used to identify all new cases of CVT (n = 5,567) in the State Inpatients Databases (SIDs) of New York and Florida (2006-2016). A new CVT case was defined as first hospitalization for CVT in the SID without prior CVT hospitalization. CVT counts were combined with annual Census data to compute incidence. Joinpoint regression was used to evaluate trends in incidence over time.

RESULTS

From 2006 to 2016, annual age- and sex-standardized incidence of CVT in cases per 1 million population ranged from 13.9 to 20.2, but incidence varied significantly by sex (women 20.3-26.9, men 6.8-16.8) and by age/sex (women 18-44 years of age 24.0-32.6, men 18-44 years of age 5.3-12.8). Incidence also differed by race (Blacks: 18.6-27.2; Whites: 14.3-18.5; Asians: 5.1-13.8). On joinpoint regression, incidence increased across 2006 to 2016, but most of this increase was driven by an increase in all age groups of men (combined annualized percentage change [APC] 9.2%, p < 0.001), women 45 to 64 years of age (APC 7.8%, p < 0.001), and women ≥65 years of age (APC 7.4%, p < 0.001). Incidence in women 18 to 44 years of age remained unchanged over time.

CONCLUSION

CVT incidence is disproportionately higher in Blacks compared to other races. New CVT hospitalizations increased significantly over the last decade mainly in men and older women. Further studies are needed to determine whether this increase represents a true increase from changing risk factors or an artifactual increase from improved detection.

Association of Menopausal Age with Unruptured Intracranial Aneurysm Morphology

Background

The prevalence of unruptured intracranial aneurysms (UIAs) increases rapidly in aging women compared with younger women. The impact of menopausal age on UIAs and treatment outcomes with endovascular therapy has not been well studied. We hypothesized that premenopausal age may have a protective effect on presentation size and treatment outcomes.

Objective

To evaluate the association of menopause with UIA size and outcome with endovascular therapy.

Methods

Retrospective analysis of consecutive female patients with UIAs treated with endovascular therapy at our academic tertiary care center. UIA characteristics, complications, and outcomes were recorded and compared.

Results

117 patients were included: 23 patients in the premenopausal age (PRM) group and 94 in the postmenopausal age (POM) group. 93.6% of all aneurysms in the PRM group were in the internal carotid artery (ICA) segments (p < 0.05). Hence only ICA segment aneurysms were further studied. A total of 21 patients in the PRM group and 60 in the POM group were found to have ICA segment aneurysms. Baseline characteristics were similar between the 2 groups. The mean size of the aneurysms in the PRM group was 8.6 ± 3.9 versus 10.8 ± 5.6 mm in the POM group (p = 0.055). There was a trend to higher aneurysm neck size seen in the POM group (4.7 ± 2.5 vs. 3.7 ± 1.7 mm; p = 0.07). The number of aneurysm lobes was higher in the PRM group (1.23 ± 0.54 vs. 1.07 ± 0.31; p = 0.18). In multivariate analysis, the PRM group had a significantly higher number of UIA lobes. Complications and endovascular therapy outcomes were similar between the 2 groups.

Conclusions

A trend to increased UIA maximal diameter and neck size was seen in the POM group compared to the PRM group. The PRM group had a significantly higher number of UIA lobes. Larger prospective trials are needed to confirm these findings.

Workflow patterns and potential for optimization in endovascular stroke treatment across the world: results from a multinational survey

BACKGROUND

The benefit of endovascular treatment (EVT) is highly time-dependent, and treatment delays reduce patients' chances to achieve a good outcome. In this survey-based study, we aimed to evaluate current in-hospital EVT workflow characteristics across different countries and hospital settings, and to quantify the time-savings that could be achieved by optimizing particular workflow steps.

METHODS

In a multinational survey, neurointerventionalists were asked to provide specific information about EVT workflows in their current working environment. Workflow characteristics were summarized using descriptive statistics and stratified by country and physician characteristics, such as age, career stage, personal and institutional caseload.

RESULTS

Among 248 respondents from 48 countries, pre-notification of the neurointerventional team was used in 70% of cases. The emergency department (ED) and CT scanner, and the CT scanner and neuroangiography suite, were on different floors in 23% and 38%, respectively. Redundant procedures in the ED were often routinely performed, such as chest x-rays (in 6%). General anesthesia was the most frequently used anesthesia protocol for EVT (42%), and an anesthesiologist was available in 82% for this purpose. 52% of the participants used a pre-prepared EVT kit.

CONCLUSION

The current structure of EVT workflows offers possibilities for improvement. While some bottlenecks, such as the spatial department set-up, cannot easily be resolved, pre-notification tools and pre-prepared EVT kits are more straightforward to implement and could help to reduce treatment delays, and thereby improve patient outcomes.

Abstract TP18: First-Pass Effect May Reduce the Impact of Delays to Treatment in Endovascular Thrombectomy: Analysis of the STRATIS Registry

Introduction: First-pass reperfusion effect (FPE) appears superior to multiple device passes in achieving good functional recovery in endovascular thrombectomy (EVT). It is unclear if this represents an epiphenomenon or a true independent effect. Historically, earlier treatment has been associated with improved functional recovery. We analyzed how these two variables interact using the STRATIS registry data.

Methods: The STRATIS registry prospectively enrolled large vessel occlusion, stroke patients, treated with Solitaire and/or Mindframe Capture low profile revascularization devices within 8 hours of symptom onset. Reperfusion was assessed by an independent core lab.

Results: A total of 984 patients were enrolled (mean age 67.8 +/- 14.7 years, 54.2% male, median NIHSS 17). Mean time from stroke onset to groin puncture was 226.4+/- 100.0 minutes. At 90 days, functional recovery (mRS 0-2) was achieved in 56.5%. Core lab assessment was performed in 824 cases with a mTICI2b/3 rate of 87.9%. Every 60-minute delay to treatment was associated with less functional recovery cOR 0.79 (95% CI, 0.68 - 0.93). In patients with first-pass effect reperfusion (FPE), delay to treatment did not affect functional recovery FPE-mTICI 2b cOR 1.03 (95% CI, 0.83 - 1.28) or FPE-mTICI 2c/3 cOR 0.96 (95% CI, 0.84 - 1.11). Poor reperfusion (FPE-mTICI <2b) maintained a negative relationship between functional recovery and delay to treatment cOR 0.76 (95% CI, 0.66 - 0.88).

Conclusion: First pass effect may reduce the impact of delays to treatment compared to historical data. Further studies to determine the mechanism of this effect are required.

Abstract WMP60: Temporal Trends in Incidence, Prevalence and Epidemiological Characteristics of Cerebral Venous Thrombosis in the United States

Background: The primary aim of this study is to describe current trends in racial-, age- and sex-specific incidence, clinical characteristics and burden of cerebral venous thrombosis (CVT) in the United States (US).

Methods: Validated International Classification of Disease codes were used to identify all adult new cases of CVT (n=5,567) in the State Inpatients Database of New York and Florida (2006-2016) and all cases of CVT in the entire US from the National Inpatient Sample 2005-2016 (weighted n=57,315). Incident CVT counts were combined with annual US Census data to compute age and sex-specific incidence of CVT. Joinpoint regression was used to evaluate trends in incidence over time.

Results: From 2005-2016, 0.47%-0.80% of all strokes in the US were CVTs but this proportion increased by 70.4% over time. Of all CVTs over this period, 66.7% were in females but this proportion declined over time (p<0.001). Pregnancy/puerperium (27.4%) and cancer (11.8%) were the most common risk factors in women, while cancer (19.5%) and central nervous trauma (11.3) were the most common in men. Whereas the prevalence of pregnancy/puerperium declined significantly over time in women, that of cancer, inflammatory conditions and trauma increased over time in both sexes. Annual age and sex-standardized incidence of CVT in cases/million population ranged from 13.9-20.2, but incidence varied significantly by sex (women: 20.3-26.9; men 6.8-16.8) and by age/sex (women 18-44yo: 24.0-32.6%; men: 18-44yo: 5.3-12.8). Age and sex-standardized incidence also differed by race (Blacks:18.6-27.2; whites: 14.3-18.5; Asians: 5.1-13.8). On joinpoint regression, incidence increased across 2006-2016 but most of this increase was driven by increase in all age groups of men (combined annualized percentage change (APC) 9.2%, p-value <0.001), women 45-64 yo (APC 7.8%, p-value <0.001) and women ≥65 yo (APC 7.4%, p-value <0.001). Incidence in women 18-44 yo remained unchanged over time .

Conclusion: The epidemiological characteristics of CVT patients in the US is changing. Incidence increased significantly over the last decade. Further studies are needed to determine whether this increase represents a true increase from changing risk factors or artefactual increase from improved detection.

Abstract WP401: Burden of Intracranial Hemorrhage in Patients With Reversible Cerebral Vasoconstriction Syndrome

Introduction: Reversible Cerebral Vasoconstriction Syndrome (RCVS) is described as reversible constriction of cerebral arteries, presenting with severe headaches and associated with hemorrhagic or ischemic strokes. There is a dearth of the literature on demographics and risk factors associated with intracranial hemorrhage (ICH) in patients with RCVS in the US.

Methods: All patients with a primary or secondary diagnosis of RCVS in 2016 Nationwide Readmission Database (NRD) using ICD-10 code I67.841 after excluding cerebral angiitis (N=57). Unique patients were included using a unique patient identifier. Weighted discharges were used to generate national estimates. ICH was defined as both intraparenchymal and subarachnoid hemorrhage. A multivariable logistic model was used to identify ICH predictors.

Results: Among total 1,152 RCVS patients, 25.7% (296) patients developed ICH. Patients with ICH mean age was (years) (Mean±SE) 47.8 ±1.2 vs. 47.0±1.1 (P=0.62), female 85.4% vs. 78.0% (P=0.06), longer inpatient LOS 12.1±0.9 vs. 6.4±0.5 days (P<0.0001) and higher inpatient cost 42,638±4,451 vs. 18,199±1,117 (P=0.018). After multivariable analysis, two independent predictors of ICH were identified: increasing age (OR 1.02, 95% CI: 1.01-1.04, P=0.042) and female gender (OR 2.37, 95%CI: 1.25-4.50, P=0.009). Patients with ICH were at a greater risk of cerebral edema (OR 13.25, 95% CI: 5.10-34.43, P<0.0001) (Figure). Among disposition, 63.2% of patients with ICH were discharged home requiring no assistance and no mortality was observed.

Conclusion: This nationally representative sample suggests that increasing age and female gender were independent predictors of ICH. There is no difference in comorbidities including migraine contrary to prior literature, modifiable lifestyle risk factors and pregnancy in this cohort. Excellent outcome was observed as the majority of patients were discharged home. Higher LOS and cost were reported in ICH cohort.

Abstract WP145: Safety of Intra-Arterial Mesenchymal Stem Cells in a Large Animal Model of Stroke: A Dose Escalation Study

Background: Despite the efficacy of thrombectomy for large vessel occlusion acute ischemic stroke (AIS) , ~50% of patients have significant residual deficits. Pre-clinical data on intra-arterially (IA) administered mesenchymal stem cells (MSCs) in stroke are promising and this approach is attractive for clinical application. While there is a concern for micro-occlusion with IA delivery due to the large size of MSCs, a dose of 1 x 10 5 MSCs given 24-48 hr in a rodent reperfusion middle cerebral artery occlusion (rMCAo) model has been shown to be safe and effective. As per STAIR recommendations, we performed a dose-escalation (DE) study of IA-MSCs in a large animal stroke model.

Methods: An endovascular canine rMCAo model using retractable platinum coil for 60-120 min was established. At 48 hr post-rMCAo, allogeniec canine MSCs were delivered using a 0.0165” microcatheter in the ipsilateral upper cervical internal carotid artery in escalating doses (based on proportion of rodent to canine total cerebral blood volume). Serial MRIs and neurological deficit scoring (NDS) were performed over 30 days. Animals were euthanized at 15-30 d post-rMCAo and brains were harvested.

Results: Female canines (n=13), age 12-36 months, weighing 22-26 kg received IA MSCs ranging from 5-80 x 10 6 (M). At doses of 5-40 M IA-MSCs no neurological worsening was observed. Serial NDS and stroke volume on MRI showed no increase post-IA-MSCs and actually showed progressive reduction. A higher numerical reduction was seen in the 10-40 M groups compared to 5 M. However, in the one canine receiving 80 M IA-MSCs, there was significant worsening of the MCA-area infarction and NDS due to microembolization at this higher dose. Gross examinations and histopathology of brain tissue were consistent with ischemia. The brain of a canine receiving 80 M cells showed differentially aged areas of necrosis supporting two ischemic events. Neuroblasts, doublecortin-positive cells, and neovascularization were observed in canine brains suggesting regenerative mechanisms.

Conclusions: These data suggest that IA-MSCs are safe in a large animal model up to 40 M IA-MSCs and is the maximum tolerated dose in this DE study. Furthermore, our data suggests that up to 40 M IA-MSCs may be promising in exploring efficacy in AIS.

Abstract WP81: Ct Perfusion is Highly Sensitive for Identifying Site of Anterior Circulation and Pca Large Vessel Occlusions

Background: While CT angiography is the standard tool to identify the site of large vessel occlusion (LVO) in acute ischemic stroke (AIS), CTP may be confirmatory or facilitate identification of the occluded vessel especially in distal LVOs. This study aims to examine the utility of CTP in localizing the site of intracranial large vessel occlusions (LVOs).

Method: We reviewed our prospective database of all patients between January 2017 and July 2019 who underwent CTP for suspected AIS. Vascular territories with perfusion abnormalities were recorded. Reference standard for occlusion was defined as confirmed LVO by CTA or digital substraction angiogram (DSA). CTP results were deemed true positive when the identified area with perfusion abnormality was the same as or overlapped with the territory of the occluded vessel on CTA/DSA.

Result: We identified 280 stroke alert patients with median NIHSS 11. LVOs were confirmed in 155 patients, of whom 146 showed corresponding perfusion abnormality (sensitivity 94.2%), and 129 with ischemic penumbra. CT perfusion was highly sensitive for occlusions in the MCA (sensitivity 95.7%, 111/116), ICA (100%, 21/21), and PCA (100%, 10/10). CTP only identified 2 of 5 (40%) basilar artery occlusions. CTP sensitivity was 97.2% (69/71), 97.5% (39/40), and 60% (3/5) for occlusions at M1, M2, and M3, respectively. Of the 125 patients who did not have LVO, 54 had falsely positive CT perfusion studies (41 with penumbra) due to stenotic processes, microvascular ischemia, chronic infarcts, or artifacts. In this cohort, 90 patients underwent mechanical thrombectomy, all with confirmed LVOs. 86/90 thrombectomy recipients (95.6%) had perfusion penumbra on initial imaging. Of the remaining 4 thrombectomy recipients who did not demonstrate perfusion mismatch on CTP, 3 had basilar occlusions.

Conclusion: CTP is highly sensitive for identifying the site of LVO in the ICA, MCA, and PCA and may be particularly useful in cases of difficult to detect LVOs particularly in M2 and PCA vessels. However, the low specificity of CTP continues to emphasize the importance of correlation with CTA and clinical findings.

Abstract 64: Transradial Approach: The Future of Neurointervention-A Muticenter Collaboration

Introduction: Transradial approach (TRA) has gained significant popularity in the neuroendovascular world over the past few years. The purpose of this study is to report early experience in TRA from high volume centers.

Methods: We reviewed charts from 4 institutions in the United States to include consecutive patients who underwent diagnostic or interventional neuroendovascular procedure through TRA from July 2018 to July 2019. Collected data included baseline characteristics, procedural variables, whether there was crossover to transfemoral access and complications.

Results: A total of 1272 patients were included in the series (age 57.2 ± 15.3, 46.3% females). Out of those, 1054 (82.9%) patients underwent diagnostic cerebral angiograms and 218 (17.1%) underwent interventional procedures. Successfully completed procedures included aneurysm primary coiling (62 patients), stent assisted coiling (44 patients), flow diversion (40 patients), balloon assisted coiling (21 patients), and stroke thrombectomy (24 patients). The large vessels were selected as following: right vertebral artery (VA) in 74.2% of the cases, right internal carotid artery (ICA) in 75.4% of the cases, left VA in 51.4% of the cases, left ICA in 69.1% of the cases. Crossover to femoral access was required in 82 (6.4%) patients (most common cause was inability to reach the target vessel in 13 patients). None of the included patients had major complication related to the access site. Minor complications related to access site were seen in 30 (2.4%) patients. Of those, 11 patients had forearm hematoma, 8 had mild-moderate vasospasm, 6 had forearm pain, and 5 had oozing from the access site.

Conclusion: In this early stage of transforming to radial-first approach for neurointerventions, TRA was reasonably safe with relatively low complication rate for both diagnostic and interventional procedures. Wide range of procedures were completed successfully using TRA.

Predictors of Balloon Guide Catheter Assistance Success in Stent-retrieval Thrombectomy for an Anterior Circulation Acute Ischemic Stroke

Introduction Mechanical thrombectomy has become the standard treatment for large vessel occlusion (LVO) in acute ischemic stroke (AIS) in well-selected patients. Although many devices and strategies exist, the use of a balloon-tip guide catheter (BGC) with stent-retriever (SR) may hold several advantages. We aim to assess the efficacy and identify predictors of technical success of this unique approach. Methods From our prospectively maintained database, we identified consecutive cases in which a BGC was used for stent-retriever thrombectomy in anterior circulation LVO between 2015 and 2016. Baseline and procedural characteristics were captured and analyzed. Predictors of technical and clinical outcomes were identified by multivariable logistic regression analysis. Results Ninety-three patients with AIS-LVO were treated with BGC-assisted mechanical thrombectomy. The mean age was 71 years old (SD 14), with 49.5% male (n=46). Pre-operative IV-tPA was administered in 55.9% (n=52) of cases. The most common location of occlusive thrombus was M1 (64.5%, n=60). Successful recanalization (mTICI=2b-3) was achieved in 86.0% (n=80) of cases while complete revascularization (mTICI-3) was achieved in 56.5% (n=52). There was a first-pass success rate of 52.7% (n=49). At discharge, 38.7% of the patients were functionally independent (mRS≤2). Multivariate analysis revealed that the middle cerebral artery location was strongly predictive of first-pass success, resulting in mTICI =2b revascularization (OR 7.10, p=0.018). Additionally, female gender (OR 2.85, p=0.042) and decreasing mTICI were associated with a poor clinical outcome (mRS≥4; OR 1.76, p=0.008). Conclusions BGC assistance in stent retrieval thrombectomy is safe and effective for AIS due to anterior circulation LVO. Further investigation is required to elucidate the optimal treatment strategy based on patient and disease characteristics.

Outcome in Direct Versus Transfer Patients in the DAWN Controlled Trial

Background and Purpose—

The impact of transfer status on clinical outcomes in the DAWN (DWI or CTP Assessment With Clinical Mismatch in the Triage of Wake-Up and Late Presenting Strokes Undergoing Neurointervention With Trevo) population is unknown. We analyzed workflow and clinical outcome differences between direct versus transfer patients in the DAWN population.

Methods—

The following time metrics were analyzed for each group: (1) last known well to hospital arrival, (2) hospital arrival to eligibility imaging, (3) hospital arrival to arterial puncture, (4) qualifying imaging to arterial puncture, (5) last known well to arterial puncture, (6) last known well to reperfusion. The primary end point was the rate of functional independence (90-day modified Rankin Scale [mRS] score, 0–2). Using univariate unconditional logistic regression, we calculated odds ratios and 95% CIs for the association between clinically relevant time metrics, transfer status, and functional independence (mRS 0–2).

Results—

A total of 206 patients were enrolled. Among these, 121 (59%) patients were transferred, and 85 (41%) patients presented directly to a thrombectomy capable center. Median time last seen well to hospital arrival time was similar between the 2 groups (678 versus 696 minutes). The time from hospital arrival to groin puncture was significantly longer in direct patients compared with transferred patients 140 minutes (interquartile range, 105.5–177.5 minutes) and 88 minutes (interquartile range, 55–125 minutes), respectively ( P <0.001). Differences in treatment effect or differences in rates of mRS 0–2 in the thrombectomy treated patients were not statistically significant in direct versus transfer patients (odds ratios for mRS 0–2, thrombectomy versus control, were 5.62 in direct and 6.63 in transfer patients, respectively, Breslow-Day P =0.817).

Conclusions—

Although transfer patients had a faster door to puncture time, benefits of thrombectomy, and rates of mRS 0 to 2 in the treatment group were similar between direct and transferred patients in the DAWN population. These results may inform prehospital and primary stroke centers triage protocols in patients presenting in the late time window.

Clinical Trial Registration—

URL: https://www.clinicaltrials.gov . Unique identifier: NCT02142283.

Association Between Time to Treatment With Endovascular Reperfusion Therapy and Outcomes in Patients With Acute Ischemic Stroke Treated in Clinical Practice

IMPORTANCE

Randomized clinical trials suggest benefit of endovascular-reperfusion therapy for large vessel occlusion in acute ischemic stroke (AIS) is time dependent, but the extent to which it influences outcome and generalizability to routine clinical practice remains uncertain.

OBJECTIVE

To characterize the association of speed of treatment with outcome among patients with AIS undergoing endovascular-reperfusion therapy.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective cohort study using data prospectively collected from January 2015 to December 2016 in the Get With The Guidelines-Stroke nationwide US quality registry, with final follow-up through April 15, 2017. Participants were 6756 patients with anterior circulation large vessel occlusion AIS treated with endovascular-reperfusion therapy with onset-to-puncture time of 8 hours or less.

EXPOSURES

Onset (last-known well time) to arterial puncture, and hospital arrival to arterial puncture (door-to-puncture time).

MAIN OUTCOMES AND MEASURES

Substantial reperfusion (modified Thrombolysis in Cerebral Infarction score 2b-3), ambulatory status, global disability (modified Rankin Scale [mRS]) and destination at discharge, symptomatic intracranial hemorrhage (sICH), and in-hospital mortality/hospice discharge.

RESULTS

Among 6756 patients, the mean (SD) age was 69.5 (14.8) years, 51.2% (3460/6756) were women, and median pretreatment score on the National Institutes of Health Stroke Scale was 17 (IQR, 12-22). Median onset-to-puncture time was 230 minutes (IQR, 170-305) and median door-to-puncture time was 87 minutes (IQR, 62-116), with substantial reperfusion in 85.9% (5433/6324) of patients. Adverse events were sICH in 6.7% (449/6693) of patients and in-hospital mortality/hospice discharge in 19.6% (1326/6756) of patients. At discharge, 36.9% (2132/5783) ambulated independently and 23.0% (1225/5334) had functional independence (mRS 0-2). In onset-to-puncture adjusted analysis, time-outcome relationships were nonlinear with steeper slopes between 30 to 270 minutes than 271 to 480 minutes. In the 30- to 270-minute time frame, faster onset to puncture in 15-minute increments was associated with higher likelihood of achieving independent ambulation at discharge (absolute increase, 1.14% [95% CI, 0.75%-1.53%]), lower in-hospital mortality/hospice discharge (absolute decrease, -0.77% [95% CI, -1.07% to -0.47%]), and lower risk of sICH (absolute decrease, -0.22% [95% CI, -0.40% to -0.03%]). Faster door-to-puncture times were similarly associated with improved outcomes, including in the 30- to 120-minute window, higher likelihood of achieving discharge to home (absolute increase, 2.13% [95% CI, 0.81%-3.44%]) and lower in-hospital mortality/hospice discharge (absolute decrease, -1.48% [95% CI, -2.60% to -0.36%]) for each 15-minute increment.

CONCLUSIONS AND RELEVANCE

Among patients with AIS due to large vessel occlusion treated in routine clinical practice, shorter time to endovascular-reperfusion therapy was significantly associated with better outcomes. These findings support efforts to reduce time to hospital and endovascular treatment in patients with stroke.

Impact of MRI Selection on Triage of Endovascular Therapy in Acute Ischemic Stroke: The MRI in Acute Management of Ischemic Stroke (MIAMIS) Registry

Background

The recently published multicenter randomized DAWN trial confirmed greater outcome benefit of endovascular therapy (ET) for anterior circulation large vessel occlusion ischemic stroke from 6 to 24 h from symptom onset compared to medical management in patients selected by advanced imaging with MRI or perfusion CT to identify mismatch between clinical deficit and infarct volume, which represents salvageable penumbra. The debate of CT over MRI is usually the potentially increase time consumption and the difficulty in establishing an adequate standardized workflow utilizing MRI during the hyperacute phase.

Purpose

While CT-based selection of patients is the current standard of care, we sought to determine the time impact of the alternative approach of MRI selection in the 0-12 h window.

Methods

In the MRI in Acute Management of Ischemic Stroke (MIAMIS) registry, we retrospectively analyzed 89 consecutive patients from January 2008 to January 2010 who presented with acute stroke symptoms with a National Institutes of Health Stroke Scale score ≥5 or aphasia within 0-12 h from symptom onset. The presence of penumbra was determined by MR perfusion-diffusion mismatch or clinical diffusion mismatch. Patients were stratified based on the presence of mismatch and clinical outcomes in patients who received ET. Imaging times were recorded.

Results

The MRI turnaround time was 95.5 ± 48.5 min. The total MRI time was 27.7 ± 12.8 min. Seventeen (19.1%) patients were found to have nonvascular etiology. Mismatch was found in 35 (48.6%) patients with acute ischemic stroke (AIS). Patients with nonvascular etiology were younger (55.7 vs. 65.6 years, p < 0.02), without any vessel occlusion or mismatch noticed in this group. We dichotomized the 39 AIS patients with vessel occlusion into two subgroups: these with mismatch and these without. Patients without mismatch were older (76.7 vs. 64.4 years, p < 0.05), more likely to have congestive heart failure (71.4 vs. 22%, p < 0.03), a higher total serum cholesterol level (196 vs. 156 mg/dL, p < 0.04), and medium to large lesions on diffusion-weighted imaging (DWI) (85.7 vs. 37.5%, p < 0.04).

Conclusions

Multimodality MRI screening for AIS symptoms for ET is feasible. Optimizing each center's protocol and the utilization of MRI with DWI only may be a time-saving alternative.

Abstract TP140: Intra-Arterial Mesenchymal Stem Cell Therapy Modulates Expression of NLRP1 Inflammasome in Animal Model of Ischemic Stroke

Background: Stroke is one of the leading causes of long-term disability worldwide. Ischemia, followed by acidosis, worsens the pathology by activating the acid sensing ion channel 1a (ASIC1a). This activated ASIC1a increases the expression of NLRP1 inflammasome in a pH dependent manner that further activates the inflammatory cascade. ASIC1a once activated triggers the influx of Ca 2+ ions and its overload contributes to neuronal injury and death in ischemic stroke. Cell based therapy with mesenchymal stem cells (MSCs) is promising for clinical translation and reported to improve neurological outcome in rodent model. We aim to test if intra-arterial (IA) MSCs can inhibit the production of inflammasome by attenuating ASIC1a expression to render neuroprotection.

Methods: Middle-aged Sprague Dawley rodents were infused with IA MSCs at 6 hours post middle cerebral artery occlusion (MCAo) followed by 24 hours of reperfusion. Rats were evaluated for neurodeficit and motor functions. Brains were harvested for infarct size estimation, biochemical analysis and western blot experiments.

Results: IA MSCs when given at a dose of 1x10 5 cells at 6 hours following ischemia confer neuroprotection as evident by reduction in infarct volume, improvement in neurodeficit scores and motor function. Increase in GSH levels and reduction in elevated nitrite and MDA levels were observed in the IA MSCs treated animals. IA MSCs infusion also attenuated the expression of ASIC1a, NLRP1, NLRP3, ASC1, IL1β and caspase-1 in the cortical brain regions following ischemia.

Conclusion: IA MSCs confers neuroprotection by attenuating acidosis by modulating NLRP1 mediated ASIC1a expression.

Keywords: Ischemic Stroke, Mesenchymal stem cell, Inflammasome, Interleukin-1β, Peri-infarct area

Abstract WP80: Association of Clot Burden Score and Thrombectomy 6 to 24 Hours After Stroke: Analysis of the DAWN Trial

Introduction: Clot burden score (CBS) is developed to evaluate anterior circulation ischemic stroke thrombus extent. Lower CBS is associated with worse functional outcome in an analysis of MR CLEAN trial without modifying the effect of mechanical thrombectomy within 6 hours after symptoms onset. An analysis of SWIFT PRIME trial showed that stent-retriever thrombectomy successfully recanalize regardless of CBS. However, thrombus that remains stagnant for longer period may be further compressed by the water-hammer effect of the systolic blood pressure, resulting in removal difficulty. We aim to explore relation of CBS with mechanical thrombectomy (MT) in the extended 6-24 hours of the DAWN trial.

Method: A blinded assessor evaluated CBS in all patients receiving CTA brain in the multicenter randomized DAWN trial for MT in acute large vessel occlusion last known well 6-24 hours (DWI or CTP Assessment with Clinical Mismatch in the Triage of Wake up and Late Presenting Strokes Undergoing Neurointervention). The cohort was divided into low CBS (0-4) and high CBS (5-10) groups. We used ordinal logistic regression for analysis of association with good outcome (mRS≤2), adjusted for significant baseline variables.

Results: 143 patients were included. Low CBS group consisted of 50 patients (29 received MT and 21 received medical management). High CBS group consisted of 93 patients (44 received MT and 49 received medical management). Baseline demographics were similar between groups. Low CBS group showed no difference in the odd of good outcome, adjusted OR 0.58 (0.3-1.14). Analysis of MT cases, Low CBS group showed a strong trend to higher procedure time (81.5±55.2 versus 56.4±35.3 min, p=0.07). There was no association of Low CBS and odds of good outcome (OR 0.9; 0.27-2.92), successful recanalization (OR 0.58; 0.18-1.89), and symptomatic intracranial hemorrhage (OR 1.67, 0.55-5.09).

Conclusion: Despite literature reporting worse outcome of anterior circulation ischemic stroke with low CBS, acute large vessel occlusion stroke with last known well 6-24 hours and low CBS treated with thrombectomy was feasible and not associated with worsen outcome compared to high CBS. However, a strong trend to higher procedure time is observed.

Abstract WP13: Time to Treatment With Endovascular Reperfusion Therapy and Outcome From Acute Ischemic Stroke in the National US GWTG-Stroke Population

Background: Randomized trials have shown the benefit of endovascular reperfusion therapy (ERT) in acute ischemic stroke (AIS) is time dependent. However, generalizability to routine practice is uncertain; and modest sample sizes have limited characterization of the degree to which onset to treatment time influences outcome from ERT.

Methods: We analyzed data of 6756 AIS patients treated with ERT at 231 hospitals between January 2015 to December 2016. Multivariable logistic regression modeling was conducted to evaluate the independent impact of onset to puncture (OTP) and door to puncture (DTP) time on efficacy and safety outcomes.

Results: Among the 6756 patients, median age was 71, 51.2% were female, and NIHSS was 17 (IQR 12-22). Median OTP was 230m (IQR 170-305) and DTP 87m (IQR 62-116). Substantial reperfusion (TICI 2b-3) was in 85.9%. At discharge, 36.9% had independent ambulation, 27.8% were discharged to home, and 23.0% were functionally independent (mRS 0-2). Symptomatic intracranial hemorrhage (sICH) occurred in 6.7% and in-hospital mortality/hospice in 19.6%. For OTP, time-outcome relationships were nonlinear, with steeper slope in 0-270m than 271-480m (see Table and Figure). DTP showed a similar nonlinear time-outcome relationship, with steeper benefit decline in the 30-120m than 121-180m period.

Conclusions: In this national registry, faster endovascular therapy start, after onset and after arrival, was associated with better ambulation and functional independence at discharge, and reduced sICH and mortality/hospice. These findings support intensive efforts to accelerate hospital presentation and endovascular treatment in patients with stroke.

Abstract WP35: A Comparison of Transradial versus Transfemoral Access in Anterior Circulation Mechanical Thrombectomy

Background: The transradial approach (TRA) to endovascular procedures decreases access site morbidity and mortality when compared to the traditional transfemoral technique (TFA). Despite its improved safety profile, there remains concerns that performing mechanical thrombectomy (MT) via TRA may lead to longer revascularization times and thus worse outcomes. However, TRA may confer an added benefit in mechanical thrombectomy (MT) where navigation of challenging aortic arch and carotid anatomy is often facilitated by a right radial artery trajectory. In this study, we compare technical and clinical outcomes in patients who underwent MT via TRA versus TFA.

Methods: We performed a retrospective review of our institutional database to identify 51 patients with challenging vascular anatomy who underwent MT for anterior circulation large vessel occlusion between February 2015 and February 2017. Patient characteristics, procedural techniques, and outcomes were recorded and TFA and TRA cohorts were compared.

Results: Of the 51 patients, 35% of patients (n=18) underwent MT via TRA. There were no significant differences between the cohorts in patient characteristics, clot location, or aortic arch type and presence of ICA tortuosity. There were no significant differences in technical or clinical outcomes between the 2 cohorts, including rates of single-pass recanalization (54.6% vs. 55.6%, p=0.949) and average number of passes (1.9 vs. 1.7, p=0.453). Mean time from vascular access to reperfusion (61.9 vs. 61.1 mins, p=0.920), rates of successful revascularization (>= TICI2b; 87.9% vs. 88.9%, p=1.0) and functional outcomes (mRS >=2, 39.4% vs. 33.3%, p=0.669) were also similar between the TFA and TRA cohorts, respectively.

Conclusions: Our results demonstrate equivalence in efficacy and efficiency between transradial and transfemoral access for MT in acute large vessel occlusion in the anterior circulation in patients with challenging vascular anatomy. Given the established advantage in access-site morbidity, our data suggests that the transradial approach may be superior to the transfemoral approach in well-selected patients undergoing MT.

Multicenter Experience with Stenting for Symptomatic Carotid Web

Background

A carotid web (CaW) is a shelf-like lesion in the posterior aspect of the internal carotid bulb and represents an intimal variant of fibromuscular dysplasia. CaW has been associated with recurrent strokes and conventionally treated with surgical excision. We report a multicenter experience of stenting in patients with symptomatic CaWs.

Methods

Retrospective review of consecutive patients admitted to 5 comprehensive stroke centers who were identified to have a symptomatic CaW and treated with carotid stenting. A symptomatic CaW was defined by the presence of a shelf-like/linear, smooth filling defect in the posterior aspect of the carotid bulb diagnosed by neck CT angiography (CTA) and confirmed with conventional angiography in patients with negative stroke workup.

Results

Twenty-four patients with stented symptomatic CaW were identified (stroke in 83% and transient ischemic attack in 17%). Their median age was 47 years (IQR 41-61), 14 (58%) were female, and were 17 (71%) black. The degree of stenosis by NASCET was 0% (range 0-11). All patients were placed on dual antiplatelets and stented at a median of 9 days (IQR 4-35) after the last event. Closed-cell stents were used in 18 (75%) of the cases. No periprocedural events occurred with the exception of 2 cases of asymptomatic hypotension/bradycardia. Clinical follow-up after stent placement occurred for a median of 12 months (IQR 3-19) with no new cerebrovascular events noted. Functional independence at 90 days was achieved in 22 (91%) patients. Follow-up vascular imaging (ultrasound n = 18/CTA n = 5) was performed at a median of 10 months (IQR 3-18) and revealed no stenosis.

Conclusions

Stenting for symptomatic CaW appears to be a safe and effective alternative to surgical resection. Further studies are warranted.

Abstract WP229: The Impact of EMS Directly Transporting Patients With Suspected Acute Ischemic Stroke to Comprehensive Stroke Centers in South Florida

Background: After endovascular therapy (EVT) became standard of care for acute ischemic stroke (AIS) in 2015, emergency medical services (EMS) in 3 urban southeast Florida counties modified their transport protocols for suspected AIS. In 2015, Broward (BC) and Palm Beach counties (PBC) phased in EMS transport of all stroke alerts to state-attested comprehensive stroke centers (CSC). Miami-Dade (MDC) adopted a severity-based protocol.

Methods: The impact of EMS policy changes was assessed using the AHA Get with the Guidelines-Stroke data prospectively collected for the Florida-Puerto Rico Stroke Registry involving 35,794 AIS cases in the 3 counties with 27 CSC between 2010 and 2016.

Results: The percent of patients transported directly by EMS from scene to CSCs in BC and PBC rose from 34% and 13% during 2010, to 97% and 86%, respectively, in 2016 (p=0.002). In MDC, it increased from 62% to 77%. In 2016, the percentage of AIS patients that presented to CSC as transfers from primary stroke centers (PSC) was 5% in BC, 8% in PBC, and 12% in MDC. Of all patients receiving IV tPA in 2016, 81% were transported by EMS and 87 % of IV tPA treatment was administered in a CSC. From 2010 to 2016, IV tPA treatment increased from 8% to 18% in CSC vs. 8% to 12% in PSC (p=0.41). By 2016 the mean door to needle time was 13 min shorter in CSCs (p<0.001). Mean interval from symptom onset to IV tPA (OTT) decreased to 112 min in CSC vs. 125 min in PSC (p=0.047) and 19% of patients at CSCs had an OTT in the “golden hour” compared to 11% at PSCs. In 2016 the mean onset to arrival in patients transferred from PSC to CSC for EVT was 109 min longer than in those directly transported to CSC. The percentage of patients receiving EVT increased overall to 6%, with 9 CSC reporting greater than 10% EVT, 5 CSC greater than 15%, and 2 greater than 20% EVT for all AIS cases.

Conclusion: Modifying EMS policies to transport most suspected AIS patients directly to CSCs was associated with higher rates of IV tPA treatment, shorter intervals to IV tPA after symptom onset, faster arrival times for EVT evaluation and higher rates of EVT compared to patients triaged to PSCs. Based on these findings, directly transporting suspected AIS patients to CSC may be a successful strategy to expedite stroke care interventions in urban centers with high CSC density.

Utilizing CT with Maximum Intensity Projection Reconstruction Bypassing CTA Improves Time to Groin Puncture in Large Vessel Occlusion Stroke Thrombectomy

Background and Purpose

Prior to thrombectomy for proximal anterior circulation large vessel occlusion (LVO) stroke, recent trials have utilized CT angiography (CTA) for vascular imaging immediately following noncontrast CT (NCCT) for decision-making, but thin-section NCCT with automated maximum intensity projection (MIP) reconstruction also has high accuracy in demonstrating the site of an occluding thrombus. We hypothesized that performing thin-section NCCT with MIP alone prior to thrombectomy improves the time to groin puncture (GP) compared to performing CTA after NCCT.

Materials and Methods

We performed a retrospective cohort study of anterior circulation LVO thrombectomy at our tertiary care academic medical center. All stroke patients evaluated with thin-section NCCT (0.625 mm) with automated MIP reconstructions alone and those who had additional CTA were included. We excluded transfer patients, in-hospital strokes, posterior circulation strokes, and patients that were evaluated with stroke imaging other than NCCT or CTA prior to thrombectomy. The study groups were compared for duration from NCCT to GP and total stroke imaging duration.

Results

From March 2008 through August 2015, 34 thrombectomy patients met the inclusion/exclusion criteria - 13 in the NCCT and 20 in the NCCT+CTA group. The total stroke imaging duration was shorter in the NCCT group than in the NCCT+CTA group (2 min [1-6] vs. 28 min [23-65]; p < 0.001). The NCCT-only group had a shorter time from NCCT to GP (68 min [32-99] vs. 104 min [79-128]; p = 0.030).

Conclusion

Avoiding advanced imaging for patients with anterior circulation LVO in whom thin-section NCCT with MIPs reveals a hyperdense sign significantly shortens the imaging-to-GP time.

Safety of Intraventricular rt-PA for Pan-Ventricular IVH Caused by a Ruptured AVM: A Case Report

Intraventricular recombinant tissue plasminogen activator (IVT rt-PA) has improved outcomes for intraventricular hemorrhage (IVH). Patients with suspected or untreated arteriovenous malformations (AVMs) have been excluded from clinical trials. We present a patient with IVH secondary to a ruptured AVM safely treated with IVT rt-PA. A 48-year-old Hispanic male with a history of dermatomyositis presented to the emergency department with sudden left-sided weakness. En route to computed tomography (CT), he became lethargic. Computed tomography revealed extensive IVH with acute hydrocephalus, which was treated with the placement of external ventricular drain with clinical improvement. Computed tomography angiogram performed did not reveal AVM. Cerebral digital subtraction angiogram (DSA) was planned due to suspicion of AVM. Prior to DSA, patient became acutely lethargic. Computed tomography imaging revealed worsening hydrocephalus. External ventricular drain was noted to be draining. Repeat CT revealed improved hydrocephalus but with left lateral ventricle dilatation. Risks and benefits of IVT rt-PA were discussed with the family and a decision was made to treat. Three doses of 1 mg IVT rt-PA were administered with resolution of midline blood and lateral ventricular dilatation with clinical improvement. Digital subtraction angiogram revealed early draining vein on right internal carotid artery injection draining into the inferior sagittal sinus representing ruptured AVM without clear nidus. Repeat DSA with possible embolization was planned after discharge. In spite of additional in-hospital complications, the patient gradually improved and was ultimately discharged home. Our case supports the idea that the use of IVT rt-PA following an IVH caused by an underlying AVM could be further explored in carefully designed clinical trials.

Abstract WP111: Diffusion Tensor Imaging of Corticospinal Tract Recovery After Intra-arterial Mesenchymal Stem Cell Infusion in a Canine Stroke Model

Background: Imaging biomarkers of stroke recovery are critical for translational studies. Diffusion tensor imaging (DTI) to assess white matter microstructure in the brain using fractional anisotropy (FA) to dertermine the structural integrity of the corticospinal tract (CST). Our prior data suggest a possible correlation between neurological recovery and the improvement in FA. The purpose of this study was to compare DTI analysis of the CST at 30 days after an ipsilateral intra-arterial (IA) Mesenchymal Stem Cell (MSCs) versus control, in canines with a reversible Middle Cerebral Artery occlusion (rMCAo).

Methods: Mongrel Hounds (n=7), aged 12-36 months, were included in this study. rMCAo was induced via endovascular approach using a detachable helical ultra-coil over 35-80 min. MSCs (1-20 millions) or saline (240 cc) were infused intra-arterially 48hrs post stroke in the ipsilesional cervical internal carotid. Brain MRIs were performed at 48h post rMCAo pre-IA cell delivery, 15 & 30 days. FA values of the right and left CST were determined. DTT was also generated for a visual analysis of the CST fibers. Weekly neuro evaluations were performed using blinded canine stroke-score.

Results: We observed a higher average change in the FA values from at 30 days post stroke in the MSCs treated group versus control (0.085 ± 0.025, n=5 versus 0.068 ± 0.058, n=2: p=0.82). A visual increase in the caliber of CST ipsilateral to stroke from IA injection to day 30 post-stroke was observed on the DTT in two of the treated canines. Figure-1 from left to right, a. FA changes, b. DTT treated group, C. DTT control.

Conclusions: Serial DTI-DTT imaging after IA MSCs therapy in large animal stroke model appears to have a trend towards higher change in FA. These findings could support further development of DTI-DTT biomarkers to measure neurologic recovery in experimental models as well as early clinical trials of novel stroke therapies.

Abstract 30: Door-to-puncture and First Pass Times for Endovascular Thrombectomy: Predictors and Changes Over Time in GWTG-stroke

Background and Purpose: Endovascular thrombectomy (EVT) is now standard of care in eligible patients with acute disabling ischemic stroke, and is more effective when delivered quickly. It is currently unclear whether time targets achieved in clinical trials can also be achieved in routine clinical practice. Here, we describe interval times from stroke onset to patient arrival in emergency room (door) to first pass/initiation of treatment in patients receiving EVT within Get With The Guidelines-Stroke hospitals (GWTG-S).

Methods: Data are from sites participating fully as Comprehensive Stroke Centers within GWTG-S from 8/2014-3/2016. Analyzed work flow times include stroke onset to door , door to imaging, imaging to arterial access, arterial access to first pass time (defined as the earliest of either deployment of a mechanical reperfusion device or intra-arterial alteplase initiated) and the composite door-to-first-pass time. Data are described overall and analyzed by calendar year quarters. Trends are tested using the Cochran-Mantel-Haenszel test.

Results: Data are reported from 1891 patients from 172 hospitals. Median time from stroke onset to door was 77 mins (IQR 46-144 min), imaging to arterial access was 91 min (64-126 min), and arterial access to first pass time was 18 min (4-31 min) (Figure). Median door-to-first-pass time was 129 min (IQR 97-171 min). Only 5.3% had a door-to-first-pass time <60 minutes while 15.1% achieved this time in <90 minutes. Slight improvements were noted in door-to-first pass (p=0.01) and imaging to arterial access time (p=0.04) by calendar quarter. Provision of IV alteplase was associated with longer imaging-to-arterial access time (median 96 vs. 85 minutes, p<0.001).

Conclusion: Although workflow is improving, efforts need to continue on streamlining workflow and saving time so that the true potential of EVT is realized. These data may inform benchmark goals for EVT workflow times.

Aspiration Thrombectomy After Intravenous Alteplase Versus Intravenous Alteplase Alone

Background and Purpose—

Thrombectomy, primarily with stent retrievers with or without adjunctive aspiration, provided clinical benefit across multiple prospective randomized trials. Whether this benefit is exclusive to stent retrievers is unclear.

Methods—

THERAPY (The Randomized, Concurrent Controlled Trial to Assess the Penumbra System’s Safety and Effectiveness in the Treatment of Acute Stroke; NCT01429350) was an international, multicenter, prospective, randomized (1:1), open label, blinded end point evaluation, concurrent controlled clinical trial of aspiration thrombectomy after intravenous alteplase (IAT) administration compared with intravenous-alteplase alone in patients with large vessel ischemic stroke because of a thrombus length of ≥8 mm. The primary efficacy end point was the percent of patients achieving independence at 90 days (modified Rankin Scale score, 0–2; intention-to-treat analysis). The primary safety end point was the rate of severe adverse events (SAEs) by 90 days (as treated analysis). Patients were randomized 1:1 across 36 centers in 2 countries (United States and Germany).

Results—

Enrollment was halted after 108 (55 IAT and 53 intravenous) patients (of 692 planned) because of external evidence of the added benefit of endovascular therapy to intravenous-alteplase alone. Functional independence was achieved in 38% IAT and 30% intravenous intention-to-treat groups ( P =0.52). Intention-to-treat ordinal modified Rankin Scale odds ratio was 1.76 (95% confidence interval, 0.86–3.59; P =0.12) in favor of IAT. Secondary efficacy analyses all demonstrated a consistent direction of effect toward benefit of IAT. No differences in symptomatic intracranial hemorrhage rates (9.3% IAT versus 9.7% intravenous, P =1.0) or 90-day mortality (IAT: 12% versus intravenous: 23.9%, P =0.18) were observed.

Conclusions—

THERAPY did not achieve its primary end point in this underpowered sample. Directions of effect for all prespecified outcomes were both internally and externally consistent toward benefit. It is possible that an alternate method of thrombectomy, primary aspiration, will benefit selected patients harboring large vessel occlusions. Further study on this topic is indicated.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT01429350.