Single low-dose targeted bevacizumab infusion in adult patients with steroid-refractory radiation necrosis of the brain: a phase II open-label prospective clinical trial

OBJECTIVE

There is an unmet need for safe and rapidly effective therapies for refractory brain radiation necrosis (RN). The aim of this prospective single-arm phase II trial was to evaluate the safety and efficacy of a single low-dose targeted bevacizumab infusion after blood-brain barrier disruption (BBBD) in adult patients with steroid-refractory brain RN.

METHODS

Ten adults with steroid-refractory, imaging-confirmed brain RN were enrolled between November 2016 and January 2018 and followed for 12 months after treatment. Bevacizumab 2.5 mg/kg was administered as a one-time targeted intra-arterial infusion immediately after BBBD. Primary outcomes included safety and > 25% decrease in lesion volume. Images were analyzed by a board-certified neuroradiologist blinded to pretrial diagnosis and treatment status. Secondary outcomes included changes in headache, steroid use, and functional status and absence of neurocognitive sequelae. Comparisons were analyzed using the Fisher exact test, Mann-Whitney U-test, linear mixed models, Wilcoxon signed-rank test, and repeated-measures 1-way ANOVA.

RESULTS

Ten adults (mean ± SD [range] age 35 ± 15 [22–62] years) participated in this study. No patients died or exhibited serious adverse effects of systemic bevacizumab. At 3 months, 80% (95% CI 44%–98%) and 90% (95% CI 56%–100%) of patients demonstrated > 25% decrease in RN and vasogenic edema volume, respectively. At 12 months, RN volume decreased by 74% (median [range] 76% [53%–96%], p = 0.012), edema volume decreased by 50% (median [range] 70% [−11% to 83%], p = 0.086), and headache decreased by 84% (median [range] 92% [58%–100%], p = 0.022) among the 8 patients without RN recurrence. Only 1 (10%) patient was steroid dependent at the end of the trial. Scores on 12 of 16 (75%) neurocognitive indices increased, thereby supporting a pattern of cerebral white matter recovery. Two (20%) patients exhibited RN recurrence that required further treatment at 10 and 11 months, respectively, after bevacizumab infusion.

CONCLUSIONS

For the first time, to the authors’ knowledge, the authors demonstrated that a single low-dose targeted bevacizumab infusion resulted in durable clinical and imaging improvements in 80% of patients at 12 months after treatment without adverse events attributed to bevacizumab alone. These findings highlight that targeted bevacizumab may be an efficient one-time treatment for adults with brain RN. Further confirmation with a randomized controlled trial is needed to compare the intra-arterial approach with the conventional multicycle intravenous regimen.

Clinical trial registration no.: NCT02819479 (ClinicalTrials.gov)

A-82 Neurocognitive Improvement after Intra-Arterial Bevacizumab for Steroid-Refractory Radiation Necrosis of the Brain

Objective

Evaluate neurocognitive change after single low-dose targeted intra-arterial (IA) bevacizumab in patients with brain radiation necrosis.

Methods

Phase II, single-arm, prospective trial. 10 adults underwent targeted 2.5 mg/kg IA bevacizumab. Neurocognitive indices (Neuropsychological Assessment Battery® and Wechsler Test of Adult Reading) were measured at baseline and 12-months to document performance in 5 domains: Attention, Language, Learning and Memory, Visuospatial, and Executive Function. Clinical indices also quantified. Data (mean ± SD, 95% confidence interval [CI], Cohen’s d) were analyzed using paired t tests. Null hypothesis rejected for p < 0.05.

Results

At baseline, Numbers-&-Letters Speed T-score (38.2 ± 10.7) indicated decreased processing speed consistent with sub-cortical pattern of illness. All other baseline neurocognitive indices were within normalized means (image). 12-months post-treatment, Numbers-&-Letters Errors T-score increased by 6.0 ± 4.9 [95%CI 1.9,10.1] (t = 3.464, d = 1.225, p = 0.010). List-Learning List-Long-Delayed-Recall T-score increased by 9.0 ± 5.6 [95% CI 4.3,13.7] (t = 4.520, d = 1.598, p = 0.003) and Design-Construction T-score increased by 3.5 ± 4.1 [95%CI 0.04,7.0] (t = 2.391, d = 0.845, p = 0.048). Volume of radiation necrosis decreased by 74.4 ± 14.7% (t = −3.308, d = 1.169, p = 0.013). Headache decreased by 84.4 ± 18.2% (t = −3.495, d = 1.236, p = 0.010). 0/10 died or exhibited AEs attributed to bevacizumab. 2/10 patients experienced radiation necrosis recurrence at months 10 and 11, respectively.

Conclusions

Single low-dose intra-arterial targeted bevacizumab led to durable neuropsychological performance increase in memory retrieval and visuospatial ability consistent with improvement in sub-cortical function. To our knowledge this is the first prospective report of this novel approach in adults. Clinical improvements mirrored neuropsychologic improvements. Randomized trials are needed comparing targeted low-dose IA bevacizumab to multi-cycle IV bevacizumab at higher doses to determine which is best alternative in brain radiation necrosis.

Impact of Age and Alberta Stroke Program Early Computed Tomography Score 0 to 5 on Mechanical Thrombectomy Outcomes: Analysis From the STRATIS Registry

Supplemental Digital Content is available in the text.

Background and Purpose:

This study investigates clinical outcomes after mechanical thrombectomy in adult patients with baseline Alberta Stroke Program Early CT Score (ASPECTS) of 0 to 5.

Methods:

We included data from the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) from patients who underwent mechanical thrombectomy within 8 hours of symptom onset and had available ASPECTS data adjudicated by an independent core laboratory. Angiographic and clinical outcomes were collected, including successful reperfusion (modified Thrombolysis in Cerebral Infarction ≥2b), functional independence (modified Rankin Scale score 0–2), 90-day mortality, and symptomatic intracranial hemorrhage at 24 hours. Outcomes were stratified by ASPECTS scores and age.

Results:

Of the 984 patients enrolled, 763 had available ASPECTS data. Of these patients, 57 had ASPECTS of 0 to 5 with a median age of 63 years (interquartile range, 28–100), whereas 706 patients had ASPECTS of 6 to 10 with a median age of 70 years of age (interquartile range, 19–100). Ten patients had ASPECTS of 0 to 3 and 47 patients had ASPECTS of 4 to 5 at baseline. Successful reperfusion was achieved in 85.5% (47/55) in the ASPECTS of 0 to 5 group. Functional independence was achieved in 28.8% (15/52) in the ASPECTS of 0 to 5 versus 59.7% (388/650) in the 6 to 10 group (P<0.001). Mortality rates were 30.8% (16/52) in the ASPECTS of 0 to 5 and 13.4% (87/650) in the 6 to 10 group (P<0.001). sICH rates were 7.0% (4/57) in the ASPECTS of 0 to 5 and 0.9% (6/682) in the 6 to 10 group (P<0.001). No patients aged >75 years with ASPECTS of 0 to 5 (0/12) achieved functional independence versus 44.8% (13/29) of those age ≤65 (P=0.005).

Conclusions:

Patients <65 years of age with large core infarction (ASPECTS 0–5) have better rates of functional independence and lower rates of mortality compared with patients >75 years of age.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239640.

Safety of the APOLLO Onyx delivery microcatheter for embolization of brain arteriovenous malformations: results from a prospective post-market study

BACKGROUND

Catheter retention and difficulty in retrieval have been observed during embolization of brain arteriovenous malformations (bAVMs) with the Onyx liquid embolic system (Onyx). The Apollo Onyx delivery microcatheter (Apollo) is a single lumen catheter designed for controlled delivery of Onyx into the neurovasculature, with a detachable distal tip to aid catheter retrieval. This study evaluates the safety of the Apollo for delivery of Onyx during embolization of bAVMs.

METHODS

This was a prospective, non-randomized, single-arm, multicenter, post-market study of patients with a bAVM who underwent Onyx embolization with the Apollo between May 2015 and February 2018. The primary endpoint was any catheter-related adverse event (AE) at 30 days, such as unintentional tip detachment or malfunction with clinical sequelae, or retained catheter. Procedure-related AEs (untoward medical occurrence, disease, injury, or clinical signs) and serious AEs (life threatening illness or injury, permanent physiological impairment, hospitalization, or requiring intervention) were also recorded.

RESULTS

A total of 112 patients were enrolled (mean age 44.1±17.6 years, 56.3% men), and 201 Apollo devices were used in 142 embolization procedures. The mean Spetzler-Martin grade was 2.38. The primary endpoint was not observed (0/112, 0%). The catheter tip detached during 83 (58.5%) procedures, of which 2 (2.4%) were unintentional and did not result in clinical sequelae. At 30 days, procedure related AEs occurred in 26 (23.2%) patients, and procedure-related serious AEs in 12 (10.7%). At 12 months, there were 3 (2.7%) mortalities, including 2 (1.8%) neurological deaths, none of which were device-related.

CONCLUSION

This study demonstrates the safety of Apollo for Onyx embolization of bAVMs.

CLINICAL TRIAL REGISTRATION

CNCT02378883.

Abstract TP19: Thrombectomy in Medium Arteries Works for Distal Vessel Occlusions in Acute Ischemic Stroke - STRATIS

Background: Mechanical thrombectomy is established for large vessel occlusions in acute ischemic stroke, but the potential role in distal vessel occlusions of medium arteries is largely unknown. Such distal arterial segments have not been measured with respect to thrombectomy devices used during endovascular therapy. We conducted a systematic analysis of arterial size, segmental anatomy and stent retriever device performance during thrombectomy.

Methods: The STRATIS angiography core lab adjudicated the exact location of the occlusion, proximal and distal device deployment, relationship to arterial bifurcations and anatomical nomenclature. Arterial diameters were measured at all of these sites. Statistical analyses examined the relationship between these variables, arterial recanalization and eTICI reperfusion.

Results: Thrombectomy was performed with various device sizes, including Solitaire 4x40 in 36.3% (306/844), Solitaire 6x30 in 31.4% (265/844), Solitaire 4x20 in 26.4% (223/844), unspecified in 3.8% (32/844), Solitaire 6x20 in 1.3% (11/844) and Solitaire 4x15 in 0.8% (7/844). Arterial diameter at the occlusion site was median 2.17mm (1.40-3.59) in the distal M1, 1.67mm (0.81-2.98) in the proximal M2, 1.50mm (0.92-1.99) in the distal M2, 1.24mm (0.67-2.00) in the M3 and 1.88mm (1.49-1.94) in the P1. Considerable overlap was noted between arterial sizes at occlusion sites carrying different segmental arterial nomenclature or vessel names. During device deployment in STRATIS, median arterial diameter at the occlusion site was 2.4mm (IQR 1.9, 3.4), 2.9mm (IQR 2.2, 3.6) at the proximal stent marker and 1.4mm (IQR 1.2, 1.7) at the distal stent marker. Substantial eTICI reperfusion (2b-3) was achieved in all distal vessel occlusions (Table 1).

Conclusions: Substantial reperfusion may be achieved with currently available mechanical thrombectomy devices for distal vessel occlusions in medium arteries.

Abstract WP24: Arterial Tortuosity is a Potent Determinant of Safety in Endovascular Therapy for Ischemic Stroke

Background: Subarachnoid hemorrhage (SAH) associated with vessel injury during endovascular therapy for acute ischemic stroke is a known complication. Arterial anatomy may predispose to increased risk of SAH and technical safety, yet factors such as clot location, arterial size and tortuosity have not been explored. We examined these anatomical factors with respect to SAH during thrombectomy.

Methods: Arterial anatomy at the site of occlusion and mechanical thrombectomy during device deployment was detailed by the STRATIS core lab. Luminal diameters, arterial branching and segmental tortuosity were measured. Arterial tortuosity was quantified using the distance factor metric (DFM). Statistical analyses included descriptives of arterial anatomy, with univariate and multivariate modeling to predict SAH.

Results: Arterial tortuosity in each segment from the proximal cerebral arteries to the site of occlusion was quantified in 790 subjects treated with mechanical thrombectomy in STRATIS. Cumulative arterial tortuosity to the site of vessel occlusion was greater in distal lesions (Table 1). SAH was clearly linked with more distal thrombectomy (p=0.017), with 19.0% of distal M2, 16.7% of M3, 7.3% of distal M1, 5.8% of proximal M2, 2.4% of distal ICA and 2.1% of proximal M1. Multivariate prediction of SAH revealed that arterial diameter was unrelated to SAH (p=0.30) when accounting for tortuosity, whereas the presence of tortuosity tripled the risk of SAH (OR 3, p<0.05).

Conclusions: This novel systematic analysis of arterial tortuosity and angiographic anatomy during mechanical thrombectomy establishes tortuosity as a determinant of SAH, providing insight for future techniques and innovative device designs.

Pipeline Embolization Device for Treatment of Craniocervical Internal Carotid Artery Dissections: Report of 3 Cases

BACKGROUND

Dissecting pseudoaneurysms of the craniocervical circulation are uncommon, accounting for only 3% of all cerebral aneurysms. These aneurysms pose a challenge due to their location and anatomic configuration. The Pipeline Embolization Device (PED) is a flow diversion technique that successfully treats aneurysms by diverting blood flow away from the aneurysm and reconstructing the diseased parent artery by altering its hemodynamics.

CASE DESCRIPTION

We report 3 cases in which the PED was used to treat craniocervical carotid artery dissection with associated pseudoaneurysms. A single PED was used in the first case, 4 PEDs were used in the second case, and 3 PEDs and a PRECISE PRO RX carotid stent were placed in the third case. All 3 patients achieved full neurologic recovery postoperatively. Cerebral angiography performed postoperatively demonstrated revascularization, good laminar flow, and no in-stent or adjacent stenosis.

CONCLUSIONS

PED placement offers a safe and effective method of treating spontaneous or traumatic craniocervical carotid artery dissections with excellent neurologic outcomes postoperatively and complete long-term aneurysmal occlusion.

Abstract TMP62: Emergency Triage to Predict Collaterals in Acute Ischemic Stroke: Imaging Bests Clinical Factors in the STRATIS Registry

Background: Collateral grade is an established determinant of outcomes in acute ischemic stroke (AIS). The triage, workflow and therapeutic options for AIS may be tailored to collaterals and identifying key predictors of collateral status may therefore be crucial. We hypothesized that degree of collateral circulation prior to endovascular therapy in AIS may be predicted at the time of initial patient evaluation and triage.

Methods: The STRATIS Registry showed that timelines, technical, and functional outcomes could be effectively attained in a large real-world cohort of endovascular therapy. Baseline clinical and imaging predictors of core lab adjudicated collateral grade (ASITN) by conventional angiography were determined, using multivariate modeling.

Results: 586 STRATIS subjects (67.5 ± 15.2 years, 52.7% male) presenting with AIS at 147.4 ± 101.8 min from symptom onset (TFSO) and median NIHSS score 17.0 (range 8.0,30.0) were analyzed. Collateral grade was poor (ASITN 0-1) in 81, moderate (ASITN 2) in 297 and good (ASITN 3-4) in 208. Baseline stroke severity inversely correlated with collaterals (NIHSS per point, OR 0.946, 0.916-0.977, p=0.001), yet no clinical variables such as age, sex or co-morbidities were predictive of collateral status. Less severe ASPECTS at imaging triage (median 9, range 2-10) was associated with better collateral grade (ASITN 0-1, median 7 (2-10); ASITN 2, 8 (3-10); ASITN 3-4, 9 (5-10), p<0.001) and the strongest predictor of collaterals during triage (per point, OR 1.608, 1.399-1.849, p<0.001). Interestingly, the predictive nature of ASPECTS was not modified by TFSO (p=NS). Specific ASPECTS regions (all cortical M1-M6, but no subcortical) affected by early ischemia were also predictive of collateral grade. In particular, insular ASPECTS changes at imaging triage was the strongest predictor of collateral grade (ASITN 0-1, 53/66 (80.3%); ASITN 2, 139/258 (53.9%); ASITN 3-4, 41/194 (21.1%), p<0.001).

Conclusions: Imaging, using only ASPECTS, during triage strongly predicts collateral grade, irrespective of time from symptom onset. Clinical variables, however, may not be used to accurately predict collaterals in the real-world practice of endovascular therapy.

Abstract WP62: Imaging With CT Perfusion Prior to Endovascular Therapy in STRATIS: Time to Rethink?

Background: Different neuroimaging triage strategies, including CT perfusion (CTP), are commonly used prior to endovascular therapy, often tailoring imaging approaches based on time from symptom onset. We analyzed whether the acquisition of CTP prior to endovascular therapy in STRATIS was related to clinical outcomes and if any possible link was noted based on time duration from symptom onset.

Methods: The STRATIS Core Lab analyzed all pre-procedural imaging in STRATIS, including the use of CTP. Acquisition of pre-procedural CTP was analyzed with respect to 90-day modified Rankin Score (mRS) clinical outcomes. Subgroup analyses explored whether this relationship was different in the 0-6 versus 6-8 hour interval from symptom onset.

Results: Among 984 subjects analyzed in STRATIS, 264 had pre-procedural CTP acquired by the imaging Core Laboratory. No association between CTP acquisition and mRS outcomes at 90 days was observed in the overall study cohort. However, among subjects treated over 6 hours from onset (n=119), a trend toward better outcomes was observed in those with CTP acquisition compared to those without (adjusted common odds ratio 1.86, p=0.092). This association was not present in subjects treated within 6 hours from onset (adjusted common odds ratio 1.10, p=0.498) (Figure).

Conclusions: Real-world data from STRATIS reveal that good clinical outcomes after endovascular therapy are not directly contingent on obtaining pre-procedural CTP. Subgroup analyses provide novel data that CTP may not be necessary 0-6 hours from onset, yet CTP may be linked with better outcomes in patients presenting after 6 hours.

Abstract TP272: Air versus Ground Transport for Interhospital Transfer Prior to Endovascular Stroke Treatment

Introduction: Interhospital transfer for endovascular treatment of large vessel occlusion (LVO) stroke results in significant delays and worse outcomes. We hypothesized that interhospital patient transfer using air transport would result in shorter transit times compared to ground ambulance.

Methods: Subjects from the STRATIS registry that underwent interhospital transfer for endovascular treatment were separated by air transport vs. ground ambulance transport and analyzed by transfer distance. The primary endpoint was transfer-time, calculated as the time from imaging at the initial hospital to arrival at the treating hospital. Also assessed was travel-time, calculated as time of departure from the initial hospital to arrival at the treating hospital.

Results: There were 232 subjects from 41 sites. Mean transfer-time for all air subjects (n=118) was 147.1 min, and for all ground subjects (n=114) was 130.0 min (p=0.019). Mean travel-time was 45.0 min for air transport and 40.2 min for ground transport (p=0.239); though the average travel distance was longer for air (65.5 miles) vs. ground (27.6 miles; p<0.001). When analyzed by distance, there was no difference between air and ground transfer-time except transfers less than 20 miles, which favored ground transportation (154.4 min vs. 119.5 min; p=0.015; see table). The lack of advantage for air transport may be accounted for by the time between imaging and departure from the initial hospital (mean 89.4 vs. 101.6 min; p=0.075), reflecting additional logistics and/or reduced availability of air transport.

Conclusions: In this large, real-world study, interhospital transfer via air transport did not result in faster transfer times compared to ground ambulance. In fact, there was an advantage to ground transportation for distances of less than 20 miles. These results suggest that ground ambulance should routinely be used for interhospital transfer of stroke patients for travel less than 20 miles.

Endovascular Treatment for Venous Sinus Stenosis in Idiopathic Intracranial Hypertension: An Observational Study of Clinical Indications, Surgical Technique, and Long-Term Outcomes

BACKGROUND

Idiopathic intracranial hypertension (IIH) is characterized by increased intracranial pressure. IIH causes significant morbidity marked by incapacitating headaches and visual disturbances. This study investigated the long-term outcomes of venous sinus stenting in a large group of patients with IIH.

METHODS

We retrospectively reviewed all patients at our institution who underwent venous sinus stenting for IIH over 6 years (July 1, 2012-June 30, 2018). A particular focus was dedicated to collecting demographic, clinical, radiologic, and outcomes data. All patients had failed medical management.

RESULTS

Of the 110 patients evaluated for IIH, 42 underwent venous sinus stenting, with a mean follow-up of 25.6 months (range, 8.7-60.7 months). The mean age was 32 years (range, 15-52 years), 38 (90%) were women, and the mean body mass index was 35.6 kg/m² (range, 18.6-47.5 kg/m²). Prior to the stenting procedure, all patients had headaches, visual disturbances, and papilledema. Of the 39 patients who had an ophthalmologic evaluation poststenting, 29 (74%) had resolution of their papilledema. Eighteen patients (43%) had complete resolution of their headaches after the stenting procedure, whereas 22 patients (52%) remained under a neurologist's care for chronic migraine and other types of headaches. Two patients underwent a restenting procedure for disease progression, and 1 patient experienced an in-stent thrombosis.

CONCLUSIONS

A multidisciplinary approach involving neurosurgeons, ophthalmologists, radiologists, and neurologists is integral in the management of patients with IIH to prevent the complications of papilledema. Venous sinus stenting offers a safe and effective means of treating IIH.

Clinical value of combined tests for tumor markers for gastric cancer

To study the clinical diagnostic value of treating gastric cancer (GC) with combined tests for tumor markers (CEA, CA199, CA242 and CA724), fifty healthy subjects, 50 patients with GC at different stages and 50 patients with benign GC were randomly selected from our hospital. These subjects were divided into a normal group A, an experimental group B and a control group C. Venous blood was drawn and tested for four serum tumor markers. The SPSS 18.0 analytic system was then used to analyze the data. Tumor markers for GC at different stages, different pathological patterns and tumor incidence are discussed. The difference in expression levels of tumor markers between group C and group A was not statistically significant (P>0.05). The differences in expression levels between group B in stage I and stage II and those of groups A and C was statistically significant (P less than 0.05). At the same time, the differences in expression levels of group B in stage III and stage IV and those of groups A and C were also statistically significant (P less than 0.01). For different sizes of tumors, taking 5 cm as a maximum, normal expression and abnormal expression of the four tumor markers was different (P less than 0.05). The tumor incidence of the combined test for the four tumor markers was conspicuously higher than that of single tests. Moreover, the difference between the tumor incidence of the combined test in stages I, II and III and that of single tests in the same stages was of statistical significance (P less than 0.05); however, the difference was not statistically significant in stage IV (P>0.05). The combined testing for tumor markers is useful for clinical diagnosis of GC.

Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke)

Supplemental Digital Content is available in the text.

Background:

Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation.

Methods:

STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0–2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass.

Results:

A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients (P<0.001). Clinical outcomes were better in the direct group, with 60.0% (299/498) achieving functional independence compared with 52.2% (213/408) in the transfer group (odds ratio, 1.38; 95% confidence interval, 1.06–1.79; P=0.02). Likewise, excellent outcome (modified Rankin Score 0–1) was achieved in 47.4% (236/498) of direct patients versus 38.0% (155/408) of transfer patients (odds ratio, 1.47; 95% confidence interval, 1.13–1.92; P=0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer; P=0.55). Intravenous tissue plasminogen activator did not impact outcomes. Hypothetical bypass modeling for all transferred patients suggested that intravenous tissue plasminogen activator would be delayed by 12 minutes, but MT would be performed 91 minutes sooner if patients were routed directly to endovascular-capable centers. If bypass is limited to a 20-mile radius from onset, then intravenous tissue plasminogen activator would be delayed by 7 minutes and MT performed 94 minutes earlier.

Conclusions:

In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes.

Clinical Trial Registration:

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640.

Abstract TMP4: Serial ASPECTS from Baseline to 24 Hours: Impact of Endovascular Therapy in STRATIS

Background: Serial ASPECTS of ischemic stroke lesion evolution from baseline to 24-hours has been established as an effective surrogate endpoint in endovascular therapy. The use of this imaging shift has not been implemented beyond thrombectomy trials to estimate impact of endovascular therapy in large-scale registry data.

Methods: The STRATIS Imaging Core Lab, blind to all clinical data, independently determined ASPECTS scores on baseline and 24-hour studies. ASPECTS regional involvement and resulting total scores were analyzed in anterior circulation occlusions in STRATIS. Statistical analyses calculated the proportion of subjects with 0 ASPECTS score shift and separately, those with shifts >4, 5, 6 points. Clinical predictors of ASPECTS shift and regional involvement were determined.

Results: Baseline ASPECTS (n=517) was 8.2 ± 1.59 (median 8.0 (2, 10)) and 24-hour ASPECTS (n=547) was 6.0 ± 2.92 (median 7.0 (0, 10)). Serial ASPECTS (n=487) revealed change of -2.1 ± 2.41 (median-1.0 (-10, 3)). Absolutely no change in ASPECTS, or 0 shift from baseline to 24 hours, occurred in 157/487 (32%). Substantial ASPECTS decline of ≥4 occurred in 117/487 (24%), with ≥5 in 76/487 (16%) and ≥6 in 51/487 (10%). ASPECTS decline was linked with baseline collaterals (ASITN 4 (n=19; -0.9 ± 1.05); 3 (n=117; -0.8 ± 1.21); 2 (n=140; -2.6 ± 2.27); 1 (n=29; -3.6 ± 2.34); 0 (n=10; -4.2 ± 3.08)) and the degree of subsequent reperfusion (oTICI 3 (n=63; -1.1 ± 1.94); 2B (n=282; -1.9 ± 2.32); 2A (n=103; -3.4 ± 2.38); 1 (n=2; -3.0 ± 1.41); 0 (n=10; -4.0 ± 2.75)). Baseline predictors of ≥6 ASPECTS decline included previous TIA (OR 3.10 (95%CI 1.32, 7.31), diabetes (OR 2.23 (95%CI 1.22, 4.07)) and baseline NIHSS (OR 1.10 (95%CI 1.03, 1.16).

Conclusions: Frozen ASPECTS or 0 shift from baseline to 24 hours occurs in about 1/3 of all cases treated with endovascular therapy in a large-scale registry. Poor collaterals, prior TIA, diabetes and elevated baseline NIHSS may be important predictors of those likely to experience infarct evolution despite reperfusion, identifying optimal candidates for neuroprotection with endovascular therapy.

Abstract TP36: Collaterals Negate Time: Topography and Determinants of Baseline ASPECTS in STRATIS

Background: ASPECTS is routinely used to estimate ischemic lesion burden in acute stroke, yet the topography and influence of collaterals has been unexplored. Imaging selection for endovascular therapy in various time epochs may also be simplified with ASPECTS. We leveraged the large-scale registry data of STRATIS to discern the role of collaterals, time and other factors in ASPECTS topography at baseline.

Methods: The STRATIS Imaging Core Lab, blind to all clinical data, independently determined ASPECTS scores and regional involvement in anterior circulation occlusions. Collateral status on baseline angiography was scored by ASITN grade. Statistical analyses described ASPECTS regional involvement or topography based on arterial occlusion site and other variables available prior to intervention, determining the influence of collaterals and time duration from onset to imaging.

Results: Baseline ASPECTS (n=573) was median 8.0 (2, 10). ASPECTS regions involved were lenticular nuclei 62.3% (357/573), insula 42.2% (242/573), caudate 23.4% (134/573), M2 13.6% (78/573), M4 9.4% (54/573), M5 9.2% (53/573), M1 4.0% (23/573), M3 2.1% (12/573), M6 1.9% (11/573) and internal capsule 0.2% (1/573). Distinct patterns or topography differentiated ICA, M1 and M2 arterial occlusion sites at angiography. Overall, higher ASPECTS (7-10 vs. ≤ 6) was linked with more robust collaterals (p<0.001) and shorter duration from onset to CT (p=0.001), yet collateral grade was unrelated to time. Ordinal multivariate logistic regression on ASPECTS containing collateral grade and time (from onset to CT) as covariates demonstrated that they were significantly associated (p<0.001 and p=0.0024, respectively) with ASPECTS.

Conclusions: ASPECTS topography and the extent of ischemic changes are a product of arterial occlusion site, collateral status and time duration. ASPECTS may infer collateral status, a pivotal determinant of outcome in endovascular therapy, irrespective of time from symptom onset.

Improved image interpretation with combined superselective and standard angiography (double injection technique) during embolization of arteriovenous malformations

OBJECTIVE

Interpretation of angioarchitecture during embolization of intracranial arteriovenous malformations (AVMs) is critical to optimizing results. We describe an adjunctive technique to aid in the interpretation of AVM embolization and improve safety.

METHODS

In the past 100 consecutive patients who underwent AVM embolization by a single surgeon (RAM), each AVM nidus was selectively catheterized and microangiography was performed. After the microcatheter contrast exited the AVM, guiding catheter angiography was performed during the same digital run. The microangiogram was digitally superimposed on the guiding catheter angiogram to delineate important landmarks such as the nidus perimeter, draining veins, and microcatheter tip, which were then drawn on the digital subtraction angiographic monitor with a marking pen in two orthogonal views.

RESULTS

Important landmarks were continually visualized during the embolization procedure despite subtracted fluoroscopy ("blank" roadmap). These techniques qualitatively helped to: 1) appreciate the overall size and morphology of the nidus, 2) clearly visualize the safe limits of the embolic injection within the nidus perimeter, 3) clearly visualize draining patterns to help avoid premature venous embolization, 4) decipher small draining veins from arteries, 5) continuously monitor the location and status of the microcatheter tip, and 6) increase the confidence of the surgeon during prolonged embolic injections.

CONCLUSION

The double injection technique, with marking pen demarcation of the nidus perimeter, venous drainage, and microcatheter tip position, was qualitatively useful in every case.

Delayed occurrence of multiple spinal drop metastases from a posterior fossa choroid plexus papilloma

✓Choroid plexus papilloma is a benign central nervous system tumor that occasionally spreads along the subarachnoid space. The authors report the case of a 49-year-old man who presented with back pain 19 years after resection of a posterior fossa choroid plexus papilloma. Magnetic resonance imaging revealed multiple spinal lesions without any residual or recurrent intracranial tumor. All spinal lesions were resected and histologically diagnosed as atypical choroid plexus papilloma. The authors suggest that patients in whom choroid plexus papilloma is diagnosed should undergo total neuraxis imaging at the time of initial diagnosis as well as periodic follow-up examinations after resection to rule out drop metastases.

Activation of glycine and glutamate receptors increases intracellular calcium in cells derived from the endocrine pancreas

We studied calcium signaling in a newly described pancreatic cell line, GK-P3, that expresses functional amino acid neurotransmitter receptors. GK-P3 cells express the first strychnine-sensitive glycine receptors reported in a permanent cell line. In addition, GK-P3 cells express alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type glutamate receptors. Both types of amino acid receptors showed electrophysiological and pharmacological behavior similar to their neuronal counterparts. The glycine receptors were permeable to Cl- and blocked by the selective antagonist strychnine. AMPA receptors showed limited permeability to Ca2+, were blocked by 6-cyano-2, 3-dihydroxy-7-nitroquinoxaline, and were potentiated by cyclothiazide. Interestingly, activation of either receptor type increased intracellular Ca2+ measured by digital imaging of Fura-2 fluorescence. These Ca2+ signals were completely blocked by 30 microM La3+, suggesting that the Ca2+ entered the cells largely through voltage-dependent Ca2+ channels. Alterations in the extracellular concentrations of Cl- and/or HCO3- had only marginal effects on glycine-evoked Ca2+ signals. However, increases in intracellular Ca2+ mediated by AMPA receptors were absent when the extracellular Na+ was replaced with an impermeant cation, N-methyl-D-glucamine. We conclude that activation of ligand-gated cation or anion channels depolarize GK-P3 cells sufficiently to activate their voltage-gated Ca2+ channels leading to increases in intracellular Ca2+ concentration. Thus, glycine and glutamate receptors may regulate Ca2+-dependent secretory mechanisms in islet cells by altering the membrane potential of these cells. Our data in GK-P3 cells support the growing weight of evidence for a role of amino acid neurotransmitters in pancreatic islets and introduce strychnine-sensitive glycine receptors as a novel target of amino acid neurotransmitter regulation in islets.

Differential expression of glutamate receptor subtypes in rat pancreatic islets

Immunocytochemistry was carried out on sections of rat pancreas to localize the expression of glutamate receptor subunits and the major pancreatic peptide hormones. Glutamate receptor expression was concentrated in pancreatic islets, and each islet cell type expressed different neuronal glutamate receptors of the alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and kainate classes. AMPA receptor subunits were expressed in alpha, beta, and pancreatic polypeptide cells, whereas kainate receptors were found predominantly in alpha and delta cells. Patch clamp electrophysiology was used to measure the functional properties of islet cell glutamate receptors. L-glutamate and other glutamate receptor agonists evoked currents in islet cells that were blocked by the selective AMPA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione and potentiated by cyclothiazide in a manner indistinguishable from that of neuronal AMPA receptors. Activation of islet cell AMPA receptors produced steady-state cation currents that depolarized the cells an average of 20.7 +/- 5.4 mV (n = 6). Currents mediated by functional kainate receptors were also observed in a line of transformed pancreatic alpha cells. Thus, L-glutamate probably regulates islet physiology via actions at both AMPA and kainate receptor classes. The pattern of receptor expression suggests that glutamate receptor activation may have multiple, complex consequences for islet physiology.