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Whether endovascular thrombectomy (EVT) improves functional outcome in patients with large-vessel occlusion (LVO) stroke that do not comply with inclusion criteria of randomized controlled trials (RCTs) but that are considered for EVT in clinical practice is uncertain. We aimed to systematically identify patients with LVO stroke underrepresented in RCTs who might benefit from EVT. Following the premises that (i) patients without reperfusion after EVT represent a non-treated control group and (ii) the level of reperfusion affects outcome in patients with benefit from EVT but not in patients without treatment benefit, we systematically assessed the importance of reperfusion level on functional outcome prediction using machine learning in patients with LVO stroke treated with EVT in clinical practice (N = 5235, German-Stroke-Registry) and in patients treated with EVT or best medical management from RCTs (N = 1488, Virtual-International-Stroke-Trials-Archive). The importance of reperfusion level on outcome prediction in an RCT-like real-world cohort equaled the importance of EVT treatment allocation for outcome prediction in RCT data and was higher compared to an unselected real-world population. The importance of reperfusion level was magnified in patient groups underrepresented in RCTs, including patients with lower NIHSS scores (0-10), M2 occlusions, and lower ASPECTS (0-5 and 6-8). Reperfusion level was equally important in patients with vertebrobasilar as with anterior LVO stroke. The importance of reperfusion level for outcome prediction identifies patient target groups who likely benefit from EVT, including vertebrobasilar stroke patients and among patients underrepresented in RCT patients with low NIHSS scores, low ASPECTS, and M2 occlusions.

BACKGROUND AND PURPOSE: Few studies assess nonstenotic carotid plaques on CTA, and the causative role of these plaques in stroke is not entirely clear. We used CTA to determine the prevalence of nonstenotic carotid plaques (

Introduction EXCELLENT (NCT03685578) is a prospective, single-arm, multicenter, real-world international registry of mechanical thrombectomy (MT) for stroke with the EmboTrap device as first line treatment. The study entails thrombus analysis of specimens collected with each MT pass. Aim of the Study To compare rates of mRS 0–2 at 90 days and clot characteristics in subjects with and without first pass effect (FPE). Methods FPE was defined as mTICI 2c/3 after one pass and non-FPE as mTICI 2c/3 after >1 pass as adjudicated by an independent core lab. Clot analysis was performed by independent central labs blinded to clinical data. mRS at 90 days was scored by investigators blinded to procedural data. Results Overall mTICI2c/3 rates were 63.7% (326/512). FPE was achieved in 37.1% (190/512) and non-FPE in 26.6% (136/512) subjects. 90 day mRS 0–2 or equal to pre-stroke was achieved in 47.2% (75/159) with FPE and in 42.1% (51/121) non-FPE patients. All-cause 90-day mortality was 19.1% (34/178) in subjects with FPE and 26.4% (34/129) in subjects with non-FPE. Major thrombus components (mean% ±SD) were as follows: RBC: FPE 45.88±20.54, non-FPE 39.08±18.23, and first pass mTICI Conclusions The high rate of ‘real-world’ FPE observed in EXCELLENT was associated with improved clinical outcomes. Clots retrieved with FPE had higher RBC and lower fibrin content compared to non FPE and to first pass mTICI Disclosure EXCELLENT is sponsored by Cerenovus. Dr. Jovin is a consultant for Neuravi, Codman Neurovascular, Stryker (PI DAWN; unpaid), Fundacio Ictus (PI REVASCAT; unpaid), and holds stock in Anaconda, Silk Road, and Blockade Medical.

Introduction Endovascular management of wide-necked bifurcation aneurysms poses a therapeutic challenge as coiling often requires the use of multiple adjunctive stent constructs to achieve successful embolization without compromising parent vessel integrity. The Neuroform Atlas Stent System is a novel low-profile, intraluminal remodeling device. The study aims to investigate the safety and efficacy of the Y-configuration constructs with the ATLAS stent for aneurysm coil embolization. Methods Patients undergoing Y-stent assisted coil embolization in the ATLAS IDE trial (Investigational Device Exemption) were identified. The primary efficacy end point was complete aneurysm occlusion (Raymond-Roy class 1) on 12-month angiography, in the absence of retreatment or parent artery stenosis (>50%) at the target location. The primary safety end point was any major stroke or ipsilateral stroke or neurological death within 12 months. Adjudication of the primary end points was performed by an independent Imaging Core Laboratory and the Clinical Events Committee. Result A total of 60 patients of were identified. The mean age was 59 and 28.3% were men. The median aneurysm size was 6.7mm with a median neck size of 4.3 mm. Aneurysm locations were as follows: basilar apex (56.7%), basilar trunk (3.3%), anterior communicating artery (20%), anterior cerebral artery (3.3%), internal cerebral artery (3.3%) and middle cerebral artery (13.3%). The composite primary efficacy end point of complete aneurysm occlusion (Raymond-Roy 1) without parent artery stenosis or aneurysm retreatment was achieved in 81.1% of patients. Overall, 1.7% (1/60) of patients experienced a primary safety end point of major ipsilateral stroke or neurological death. Conclusions In the ATLAS IDE aneurysm cohort premarket approval study, the Neuroform Atlas stent with adjunctive Y-stent coiling met the primary end points and demonstrated high rates of long-term complete aneurysm occlusion at 12 months, with low rates of morbidity. Disclosures A. Jadhav: None. S. Desai: None. R. Hanel: None. D. Frei: None. A. Khaldi: None. S. Hetts: None. O. Zaidat: None. B. Jankowitz: None.

Background: Severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has been associated with a significant risk of thrombotic events in critically ill patients. Aims: To summarize the findings of a multinational observational cohort of patients with SARS-CoV-2 and cerebrovascular disease. Methods: Retrospective observational cohort of consecutive adults evaluated in the emergency department and/or admitted with coronavirus disease 2019 (COVID-19) across 31 hospitals in 4 countries (2/1/2020 - 06/16/2020). The primary outcome was the incidence rate of cerebrovascular events, inclusive of acute ischemic stroke, intracranial hemorrhages (ICH), and cortical vein and/or sinus thrombosis (CVST). Results: Of the 14,483 patients with laboratory-confirmed SARS-CoV-2, 172 were diagnosed with an acute cerebrovascular event (1.13% of cohort; 1130/100,000 patients, 95%CI 970-1320/100,000), 68/171 (40.5%) of whom were female and 96/172 (55.8%) were between the ages 60-79 years. Of these, 156 had acute ischemic stroke (1.08%; 1080/100,000 95%CI 920-1260/100,000), 28 ICH (0.19%; 190/100,000 95%CI 130 - 280/100,000) and 3 with CVST (0.02%; 20/100,000, 95%CI 4-60/100,000). The in-hospital mortality rate for SARS-CoV-2-associated stroke was 38.1% and for ICH 58.3%. After adjusting for clustering by site and age, baseline stroke severity, and all predictors of in-hospital mortality found in univariate regression (p Conclusions: COVID-19 is associated with a small but significant risk of clinically relevant cerebrovascular events, particularly ischemic stroke. The mortality rate is high for COVID-19 associated cerebrovascular complications, therefore aggressive monitoring and early intervention should be pursued to mitigate poor outcomes.

Introduction The Penumbra SMART COIL® System includes a novel generation of embolic coils comprising complex and WAVE shape properties with varying levels of softness to promote dense packing and durable long-term occlusion. We present the final analysis of 997 patients at 68 U.S./Canada sites with up to 1-yr follow-up in the SMART registry to assess the utility of the SMART COIL System in the treatment of intracranial aneurysms and other malformations. Materials and Methods The SMART registry is a prospective, multi-center registry assessing the embolization of neurovascular lesions using the Penumbra SMART COIL System. Procedures must employ ≥75% of SMART, PC400, or POD coils to meet inclusion criteria. SMART registry endpoints included retreatment rates through 1-yr (±6-mo) follow-up, procedural device-related serious adverse events (SAE), and the ability to achieve adequate occlusion at immediate post-procedure. Results This analysis of 997 patients (72.1% female; mean age 59.6±13.0 yr) included cerebral aneurysms (91.0%, 907/997); arteriovenous malformations (1.1%); fistulae (4.1%); and other lesions (3.8%). Aneurysms, of which 31.8% were ruptured, were small (≤10 mm) in 85.3% (774/907) of patients, large (>10 mm to 25 mm) in 14.4% (131/907), and giant (>25 mm) in 0.2% (2/907); 63.5% (555/874) of patients had wide-neck aneurysms (dome-to-neck ratio For all lesions, median coil deployment time, defined as the time from the first coil deployed until the last coil detached, was 16.0 min (IQR 8.0–32.0), and median time of fluoroscopic exposure was 37.0 min (IQR 24.0–56.0). Stent-assisted coiling was performed in 5.7% of patients, and balloon-assisted coiling was performed in 18.7% of patients. Median packing density (calculated for aneurysms only) was 29.1% [IQR 21.0–38.8]. For aneurysms, Raymond Occlusion Class (RROC) I and II was achieved in 79.7% (719/902) of cases at immediate post-procedure and in 90.1% (643/714) at 1-yr follow-up, with a recanalization rate of 12.8% (91/710) and a retreatment rate of 7.1% (52/733). In multivariate models, a large or giant aneurysm size (odds ratio [OR]=2.45, p=0.0030), balloon-assisted coiling (OR=1.84, p=0.0195), ruptured aneurysm status (OR=3.91, p For non-aneurysm lesions, complete angiographic occlusion was achieved in 85.2% (23/27) of lesions post-procedure, with a recanalization rate of 6.1% (3/49) and a retreatment rate of 1.9% (1/53) at 1-yr follow-up. Overall, procedural device-related serious adverse events (SAE) were observed in 2.6% (26/997) of subjects. Conclusion The final results of the SMART Registry, a prospective registry with 997 subjects, demonstrate that the SMART COIL System achieves safe and adequate embolization in a wide variety of neurovascular lesions with low retreatment rates over 1 yr. Large aneurysm size and balloon-assisted coiling were predictive of incomplete occlusion at 1-yr and retreatment through 1-yr follow-up. Disclosures A. Spiotta: None. M. Park: None. R. Bellon: None. B. Bohnstedt: None. C. Schirmer: None. R. DeLeacy: None. D. Fiorella: None. B. Woodward: None. B. Baxter: None. S. Kale: None. O. Zaidat: None. P. Sunenshine: None. A. Yoo: None. M. Kabbani: None. K. Liu: None. R. Starke: None. A. Reeves: None. K. Snyder: None. T. Sivapatham: None. T. Dumont: None.

Introduction/Purpose Initial clinical evidence has shown that coiling with the SMART COIL® System (Penumbra, Inc.) is a safe and durable treatment option for intracranial aneurysms.1–5 The WAVE™ Extra Soft Coil (WAVE) is part of the SMART Coil System and is specifically designed as a fill and finish coil. The primary objective of the SURF study, a post-market registry, is to assess the utility of WAVE as a fill and finish coil to support adequate occlusion at one year follow-up. A secondary objective is to compare the ability of digital subtraction angiography (DSA) and magnetic resonance angiography (MRA) to detect incomplete occlusion in the coiled aneurysms. Materials and Methods SURF is a post-market, prospective, multicenter, single-arm, observational study that will enroll approximately 800 consecutive patients at up to 50 centers in North America. Patients age ≥ 18 years, having embolization of intracranial aneurysms, with WAVE as the final finishing coil and Penumbra SMART COIL System accounting for at least 75% of total number of coils implanted, will be included. All subjects will be followed for approximately 1 year. The primary efficacy endpoint is adequate occlusion defined as Raymond-Roy Occlusion Class I and II at final follow-up. The primary safety endpoints are serious adverse events (SAE) within 24 hours post-procedure and device-related SAE up to 7 days or discharge. Imaging will be analyzed by an independent core lab to assess aneurysm occlusion rates at follow-up. Imaging modalities include DSA, computed tomography angiography (CTA), and/or MRA. A comparative analysis between imaging modalities will be performed for patients with DSA and MRA. Results The trial is currently recruiting. Enrollment began November 2019 and the estimated date for study completion is June 2023. Imaging and clinical data collection and core laboratory review are ongoing. Conclusion We report the design of the SURF study, a post-market registry that evaluates the safety and performance of the Penumbra SMART COIL System, including WAVE as a fill and finish coil, in the treatment of intracranial aneurysms. References Daniel B, Henrik S, Ioannis T, Veit R, Marios-Nikos P. SMART coils for intracranial aneurysm repair - a single center experience. BMC Neurol. 2020 Jan 29;20(1):38. Sokolowski JD, Ilyas A, Buell TJ, Taylor DG, Chen CJ, Ding D, Raper DMS, Liu KC. SMART coils for intracranial aneurysm embolization: Follow-up outcomes. J Clin Neurosci 2019 Jan;59:93–97. Ilyas A, Buell TJ, Chen CJ, Ding D, Raper DMS, Taylor DG, Sokolowski JD, Liu KC. SMART coils for intracranial aneurysm embolization: Initial outcomes. Clin Neurol Neurosurg 2018 Jan;164:87–91. Spiotta AM, Fargen KM, Lena J, Chaudry I, Turner RD, Turk AS, Huddle D, Loy D, Bellon R, Frei D. Initial Technical Experience with the SMART Coil for the Embolization of Intracranial Aneurysms. World Neurosurg 2017 Jan;97:80–85. Stapleton CJ, Torok CM, Patel AB. Early experience with the Penumbra SMART coil in the endovascular treatment of intracranial aneurysms: Safety and efficacy. Interv Neuroradiol 2016 Dec;22(6):654–658. Disclosures C. Schirmer: None. I. Kaminsky: None. M. Chaudry: None. O. Zaidat: None. A. Alshekhlee: None. P. Ramakrishnan: None. M. Taqi: None.

Background and purpose Stent-assisted coil embolization using the new generation Neuroform Atlas™ Stent System has shown promising technical, safety, and clinical feasibility and efficacy. Here, we present the one year angiographic and efficacy results of the anterior circulation cohort in the ATLAS Investigational Device Exemption (IDE) Trial. Methods ATLAS IDE is a prospective, multicenter, single-arm, open label study of unruptured wide-necked (neck ≥4 mm or dome-to-neck ratio 50% at the target location. The primary safety endpoint was any major stroke or ipsilateral stroke or neurological death within 12 months. Adjudication of the primary endpoints was performed by an imaging core laboratory and the Clinical Events Committee for ATLAS. Results A total of 182 patients with unruptured wide-necked anterior circulation aneurysms at 25 US centers were enrolled. The mean age was 60.3±11.4 years, 73.1% (133/182) women, and 80.8% (147/182) Caucasian. Mean aneurysm size and dome-to-neck ratio was 6.1±2.2 mm and 1.2±0.3, respectively. Sixty-four (35.2%) aneurysms were located in the anterior communicating artery. Mean procedure duration was 110.2±47.0 minutes. Technical success was achieved in 100% (182/182) of patients. Follow-up imaging data at 12 months was available in 84.1% (153/182) of patients. The primary efficacy endpoint was achieved in 84.7% [95%CI: 78.6,90.9] of subjects and the incidence of primary safety endpoint failure was 4.4% (8/182; 95%CI: 1.9, 8.5). Conclusion In the ATLAS IDE anterior circulation cohort pre-market approval study, the Neuroform ATLAS stent with adjunctive coiling demonstrated high rates of long-term complete occlusion at 12 months, with excellent technical success and safety. Disclosures O. Zaidat: None. R. Hanel: None. E. Sauvageau: None. A. Aghaebrahim: None. E. Lin: None. A. Jadhav: None. T. Jovin: None. A. Khaldi: None. R. Gupta: None. A. Johnson: None. D. Frei: None. D. Loy: None. A. Malek: None. G. Toth: None. A. Siddiqui: None. J. Reavey-Cantwell: None. A. Thomas: None. S. Hetts: None. B. Jankowitz: None.

Background and purpose Limited data exists on the benefit of mechanical thrombectomy (MT) in acute ischemic stroke patients presenting with low ASPECTS (Alberta Stroke Program Early Computed Tomography (CT) Score). The aim of this substudy was investigate the outcome of low ASPECTS (0–5) patients undergoing mechanical thrombectomy in the Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) Registry. Methods Data from the STRATIS Registry, a prospective, multicenter, non-randomized, observational study of AIS LVO patients treated with the Solitaire stent-retriever as the first choice therapy within 8 hours from symptoms onset, was used to identify patients with baseline ASPECTS 0–5. CT ASPECTS was adjudicated by a core lab blinded to clinical outcomes. Results A total of 57/763 (7.5%) patients had a baseline ASPECTS 0–5, of which 10 were ASPECTS 0–3 and 47 ASPECTS 4–5. Mean baseline NIHSS was 19.9±5.1. The majority of patients presented with ICA (42.1%) and M1 (47.4%) occlusions. IV-rtPA was administered in 68.4%. Mean onset to arterial puncture was 276±102.9 minutes and puncture to reperfusion time was 45.3±25.3 minutes. The majority of patients (85.5%) achieved substantial reperfusion (mTICI≥2b). Ninety-day outcome was reported in 52/57 (91.2%). The rate of good functional outcome (mRS≤2) was 28.8% (versus 59.7% in ASPECTS 6–10 group, p Conclusion In the STRATIS Registry, low ASPECTS 0–5 is associated with lower functional outcomes in patients undergoing mechanical thrombectomy. Clinical outcome in low ASPECTS may be age dependent. Prospective studies are needed to understand the benefit of MT in this patient population. Disclosures O. Zaidat: None. D. Liebeskind: None. A. Jadhav: None. S. Ortega-Gutierrez: None. V. Szeder: None. D. Haussen: None. D. Yavagal: None. M. Froehler: None. R. Jahan: None. T. Yao: None. N. Mueller-Kronast: None.

Introduction Achieving complete revascularization after a single attempt with mechanical thrombectomy (First pass effect, FPE) in the setting of an acute ischemic stroke due to large vessel occlusion (LVO) is associated with significantly higher rates of a good clinical outcome. We aim to identify predictors of FPE in a large real word registry of patients undergoing thrombectomy. Methods Data were analyzed from the STRATIS registry -- a prospective, nonrandomized study of patients undergoing neurothrombectomy with the Solitaire device. A total of 984 patients treated at 55 sites were analyzed. Univariate and multivariable logistic regression was used to assess the relationship between patient characteristics (demographics, clinical, occlusion location, collateral grade) and procedural features with FPE. Complete data was only available for 930 patients. Results First pass effect was achieved in 40% (ns=372) of patients. Patients in the FPE group were older (69 ±15 vs 67 ±15 years, p=0.02) and had less internal carotid artery (ICA) occlusions (17% vs 28%, p=0.001). While rates of symptomatic intracranial hemorrhage (0.6% vs 2.2%, p=0.13) were comparable, rates of mRS 0–2 at 90 days were higher (66% vs 49%, p≤0.001) and mortality at 90 days (12% vs 19%, p=0.008) were lower in the FPE group compared to the non-FPE group. Multivariable regression analysis identified absence of ICA occlusion (p=0.01), the use of a balloon guided-catheter (p=0.001) and better collateral grade (p≤0.001), as independent predictors of FPE. Conclusion Non-ICA site of occlusion, the use of a balloon-guided catheter and better collateral grade are independent predictors of FPE. Further understanding of these factors may influence choice of thrombectomy device and technique. Disclosures A. Jadhav: None. O. Zaidat: None. S. Desai: None. R. Nogueira: None. N. Mueller-Kronast: None. T. Jovin: None. D. Liebeskind: None.

Background A significantly large number of patients with emergent large vessel occlusion (ELVO) fail to achieve favorable outcomes despite successful recanalization. Why some patients do not achieve functional independence despite successful revascularization is an important question. There is a paucity of prospective data on the predictors of unfavorable outcomes despite successful recanalization during mechanical thrombectomy for ELVO. Objective This study was performed to determine the predictors of unfavorable outcomes in patients receiving successful recanalization (modified thrombolysis in cerebral infarct, mTICI grade ≥2b) in a prospective multicenter cohort of patients with ELVO. Methods This was a secondary analysis of data collected from ARISE II study (Analysis of Revascularization in Ischemic Stroke With EmboTrap). ARISE II was a prospective, multicenter single arm study on the efficacy of EmboTrap Revascularization Device. Patients who achieved mTICI score of 2b or greater within 3 passes were included in this study. Patients with incomplete follow up were excluded from the study. A univariate and multivariate logistic regression was performed to determine the independent predictors of unfavorable outcomes at 90 days (defined as mRS 3–6). The variables tested as predictors included age, gender, collateral grade, ASPECTS, mode of transfer, National health institute stroke scale (NIHSS) score, use of intravenous tissue plasminogen activator, number of passes, clot location, final mTICI and symptomatic intracranial hemorrhage (sICH). Odds ratio (OR) with 95% confidence interval (CI) were reported. Results One hundred seventy six patients were included in this secondary analysis of ARISE II data. Unfavorable outcomes (mRS=3–6) at 3 months were seen in 52 (29.6%) patients. Females constituted 54.88% of total population. Mean age was 67.15 years. Mean NIHSS score was 15.85±4.71. M1 was the most common site of occlusion with 54.55% followed by M2 (25.0%) and ICA (15.91%). Delay from stroke onset to the deployment of stent retriever was 3.97±1.44 hours. Ninety (51.14%) patients required a single pass. On univariate logistic regression analysis age, ASPECTS, collateral grade, time from stroke onset to the deployment of stent retriever, duration of procedure, NIHSS score, and sICH were found to be significant predictors of unfavorable outcomes. On multivariate analysis collateral grade (OR, 0.24, 95% CI 0.06–0.94, p value 0.04), NIHSS score (OR 1.28, 95% CI 1.15–1.43, p value Conclusion Collateral grade, NIHSS score at presentation, and number of passes are independent predictors of unfavorable outcomes at 90 days. Disclosures A. Siddiqui: 1; C; Co-investigator NIH/NINDS 1R01NS091075. 2; C; Canon Medical System US, Boston Scientific, Amnis Therapeutics, Cerebrotech Medical Systems, Silk Road, Corindus Inc., Blockade Medical, Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp., Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical, VasSol, W.L. Gore & Associates. M. Waqas: None. T. Andersson: 2; C; Neuravi, Ablynx, Amnis Therapeutics, Medtronic, Rapid Medical, Stryker. J. Saver: 1; C; Medtronic-Abbott, Neuravi. H. Mattle: None. H. Bozorgchami: None. R. Chapot: None. A. Narata: None. A. Yoo: 1; C; Penumbra, Neuravi, Cerenovus. M. Ribo: None. O. Zaidat: 2; C; Stryker, Medtronic, Neuravi, Penumbra.

Introduction Swift and complete revascularization in large vessel occlusion (LVO) stroke is associated with better functional outcomes. First pass effect (FPE), achievement of TICI 2C/3 revascularization on the first pass, is a new metric of technical success of endovascular thrombectomy (EVT). We aim to identify predictors of FPE and TICI 3 revascularization in the ARISE II study. Methods Anterior circulation LVO [ACLVO-internal carotid (ICA) and middle cerebral artery (MCA-M1)] strokes from the ARISE II study were used for this analysis. Core-lab adjudicated TICI scores after the first pass of EmboTrap were collected. FPE and modified FPE (mFPE) were defined as first pass achievement of TICI 2C/3 and TICI ≥2B, respectively. Demographic, clinical and radiographic parameters were analyzed. Multivariable logistic regression was performed to identify predictors. Results A total of 161 ACLVOs underwent thrombectomy in the ARISE II study. Mean age was 67 ±13 years and 43% (n=69) were male. Mean NIHSS and median ASPECTS were 16 ±5 and 10, respectively. While FPE was achieved in 37% (n=59), mFPE was seen 43% (n=69) patients. Multivariable logistic regression was performed using age, sex, use of IV-tpA, BMI, NIHSS, vascular risk factors, ASPECTS, collateral status (ASITN), occlusion location and use of balloon-guided catheter as variables. While absence of ICA occlusion (p=0.07, OR-8.6, 0.8–90) can predict FPE, there were no independent predictors of mFPE. Independent predictors of TICI 3 after 3 passes include use of balloon guide catheter (p=0.01, OR-0.033, 0.003–0.535) and higher ASITN score(p=0.04, OR-10.2, 1–100). Conclusion Absence of internal carotid artery occlusion predicts FPE and the use of balloon guide catheter and favorable collaterals predicts complete revascularization. These results support the consideration of routine BGC use with the Embotrap device to achieve complete revascularization. Disclosures A. Jadhav: None. S. Desai: None. D. Liebeskind: None. A. Yoo: None. H. Bozorgchami: None. M. Ribo: None. J. L: None. H. Mattle: None. T. Andersson: None. O. Zaidat: None.

Background and purpose Recent data suggests that intra-arterial (IA) thrombolytics may be a safe rescue therapy (RT) for acute ischemic stroke (AIS) patients after failed mechanical thrombectomy (MT); however, its safety and efficacy in MCA occlusions remains unclear. Here, we investigate the use of IA tissue plasminogen activator (IA-rtPA) as RT in MCA occlusions in the Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke (STRATIS) Registry. Methods The STRATIS Registry was a prospective, multicenter, non-randomized, observational study of AIS LVO patients treated with the Solitaire stent-retriever as the first choice therapy within 8 hours from symptoms onset. Clinical and angiographic outcomes were compared in patients with MCA occlusions treated with and without IA-rtPA. Results A total of 680/938 (72.5%) patients with IA-tPA use harbored MCA occlusions, of which 585 (86.0%) and 95 (14.0%) were in the no IA-rtPA and IA-rtPA groups, respectively. Baseline demographics were well-balanced between the cohorts. The majority of MCA occlusions were located in the M1 segment, with 76.1% in the no IA-rtPA group and 74.7% in the IA-rtPA group (p=0.80). IV-rtPA was administered in 64.4% and 71.6% of the no IA-rtPA and IA-rtPA patients (p=0.20). Median IA-rtPA dose was 4mg (IQR 2–10) in the IA-rtPA cohort. Onset to puncture time was less than 6 hours in 88.6% (597/674) of patients. Mean onset to arterial puncture time was shorter in the IA-rtPA group (196.7±109.9 versus 228.2±97.9 minutes, p=0.004); however, mean puncture to procedure end time was longer in the IA-rtPA group than the no IA-rtPA group (74.5±41.5 versus 59.5±33.6 minutes). Mean number of passes (2.0±1.2 versus 1.6±1.0, p=0.005) and rate of distal embolization (53.4% versus 72.1%, p=0.001) were significantly higher in the IA-rtPA group. The rate of substantial reperfusion (mTICI≥2b) was similar in the cohorts (89.9% versus 86.0%, p=0.28). Rates of symptomatic intracranial hemorrhage (sICH) (1.7% versus 2.2%, p=0.68), good functional outcome (mRS≥2, 60.5% versus 58.0%, p=0.85), and mortality (13.9% versus 13.6%, p=0.96) at 90days did not differ between the two groups. Conclusion Use of IA-rtPA as rescue therapy after failed mechanical thrombectomy in MCA occlusions was not associated with an increased risk of sICH or mortality in the STRATIS Registry. More studies are needed to understand the safety and efficacy of IA thrombolysis as rescue therapy in this patient population. Disclosures A. Castonguay: None. S. Zaidi: None. M. Jumaa: None. O. Zaidat: None. D. Liebeskind: None. H. Salahuddin: None. N. Mueller-Kronast: None.

Rationale The EmboTrap Revascularization Device has been shown to be effective in achieving successful reperfusion in emergent large vessel occlusion (ELVO) patients, with clinical outcomes comparable to existing stent retriever devices. Prospective multicenter data on the real-world experience with EmboTrap is not available. Aim The primary objective of the study is to assess the efficacy of routine, real-world experience of the EmboTrap and to explore the associations between imaging characteristics at presentation, including volume of core and penumbra, final infarct volume, histologic clot characteristics, subject comorbidities, revascularization rate, and clinical outcomes. Design This is a prospective, global, multi-center, single-arm, observational registry. Up to 1000 subjects at 50 different sites in Europe and US may be enrolled in the study. Adult patients (>18 years) with angiographically confirmed ELVO, and treated with EmboTrap as first attempted device will be eligible for participation in the study. Patients with confirmed pregnancy or enrolled in another investigational clinical trial will be excluded. This study will utilize expanded thrombolysis in cerebral infarction score (eTICI) and an independent Core Imaging Laboratory to assess baseline CT/MR imaging (e.g. ASPECTS, infarct volume, clot location, perfusion), procedural angiography (eTICI score for every pass, emboli to new territories, collateral score) and post-procedure CT/MR imaging (infarct volume, intracranial hemorrhage). All imaging will be read independently by an experienced Imaging Core Lab blinded to all clinical data. In addition, an independent Core Laboratory will also perform clot analysis. Study outcomes Pre-specified endpoints of the study include successful revascularization (modified thrombolysis in cerebral infarction score ≥ 2b), first pass effect (eTICI ≥ 2c in a single pass without rescue), number of passes, functional independence assessed as modified Rankin Score of ≤ 2 at 90 days, 2 rates of embolization to new territory, symptomatic intracranial hemorrhage at 24 hours and all-cause mortality at 90 days. Analysis Standard descriptive statistical summaries will be provided. For categorical endpoints, two-sided exact 95% confidence intervals will be presented. Regression analyses will be conducted to determine the association between baseline subject comorbidities, clot characteristics and reperfusion, with a focus on imaging findings. The plan for per pass analysis both by an independent core imaging laboratory and by an independent clot analysis laboratory sets apart this registry from other similar studies. In addition, the reperfusion assessment by the independent core lab will be using innovative eTICI. Disclosures A. Siddiqui: 1; C; Co-investigator NIH/NINDS 1R01NS091075. 2; C; Amnis Therapeutics, Boston Scientific, Canon Medical Systems USA Inc, Cerebrotech Medical Systems, Cerenovus, Corindus Inc., Endostream Medical Ltd, Guidepoint Global Consulting, Imperative Care, Integra LifeSciences Corp, Medtronic, MicroVention, Q’Apel Medical Inc, Rapid Medical, Rebound Therapeutics Corp., Serenity Medical Inc, Silk Road Medical, StimMed, Stryker, Three Rivers Medical, VasSol, W.L. Gore & Associates. 4; C; Amnis Therapeutics, Apama Medical, Blink TBI Inc, Buffalo Technology Partners Inc, Cardinal Consultants, Cerebrotech Medical Systems, Cognition Medical, Endostream Medical Ltd, Imperative Care, International Medical Distribution Partners, Neurovascular Diagnostics Inc, Q’Apel Medical Inc, Rebound Therapeutics Corp, Rist Neurovascular In, Serenity Medical, Silk Road Medical, StimMed, Synchron, Three Rivers Medical Inc, Viseon Spine. T. Andersson: 2; C; Neuravi, Ablynx, Amnis Therapeutics, Medtronic, Rapid Medical, Stryker. S. De Meyer: None. K. Doyle: None. J. Fiehler: None. W. Hacke: None. R. Hanel: 2; C; Three Rivers Medical, Medtronic, Microvention, Codman, Stryker. T. Jovin: 2; C; Neuravi, codman, Medtronic, Stryker, Silk Road, Anaconda, Blockade Medical. D. Kallmes: None. D. Liebeskind: None. A. Yoo: 2; C; Cerenovus. O. Zaidat: 2; C; Stryker, Medtronic, Neuravi, Penumbra. R. Nogueria: 2; C; Neuravi, Medtronic, Penumbra, Stryker.

Background and purpose The DEFUSE 3 and DAWN trials have shown the benefit of thrombectomy beyond 6 hours of stroke symptom onset. The purpose of this study is to evaluate the real-world outcomes of patients treated with stent retriever thrombectomy beyond 6 hours of stroke onset using combined individual patient data from the North American Solitiare Stent Retriever Acute Stroke (NASA) and Trevo Stent-Retriever Acute Stroke (TRACK) registries. Methods Pooled analysis of individual patient data of all cases of anterior circulation acute ischemic stroke (AIS) from NASA and TRACK was performed to compare radiographic and clinical outcomes of patients presenting within first 6 or beyond 6 hours of stroke symptom onset. Results Out of 830 patients with anterior circulation AIS patients from the NASA and TRACK registries, 32.7% (271 patients) underwent thrombectomy beyond the first 6 hours of symptom onset. There was a similar distribution of age and cerebrovascular risk factors in patients arriving within the first 6 and beyond 6 hours of stroke symptom onset. Both groups of patients had similar approaches to thrombectomy using the Solitaire (NASA registry) and Trevo (TRACK registry) stent retrievers, including the use of a balloon-guide catheter, continuous aspiration or general anesthesia (p=0.12, 0.15 and 0.52, respectively). The rates of successful recanalization, defined as TICI 2b/3, were 79.4% in patients within stroke 0–6 hours, 75.6% within 6–16 hours and 85.0% within 16–24 hours (p=0.04). The rates of good clinical outcome, defined as modified Rankin Scale 0–2, mortality and symptomatic Intracerebral hemorrhage were similar: 48.2%, 20.6% and 8.0% within 0–6 hours, 46.2%, 21.6% and 11.02 within 6–16 hours, and 38.9%, 33.3% and 5% within 6­16 hours (p=0.8, 0.6 and 0.5, respectively). Conclusions In real world experience with patients who presented with anterior circulation AIS, using the Solitaire and Trevo thrombectomy devices beyond the first 6 hours of symptom onset proved to be equally safe and effective when compared to patients with symptom onset within the first 6 hours. Disclosures M. Mokin: 2; C; Canon medical. A. Abou-Chebl: None. A. Castonguay: None. R. Nogueira: 1; C; Stryker, Medtronic, Penumbra. 2; C; Styker Neurovascular, Covidien. J. English: 2; C; Stryker. H. Farid: None. R. Gupta: 2; C; Stryker. C. Martin: None. W. Holloway: None. D. Haussen:None. N. Mueller-Kronast: None. O. Zaidat: 2; C; Stryker, Medtronic.

Background and Purpose— Previous work that predated the availability of the safer stent-retriever devices has suggested that general anesthesia (GA) may have a negative impact on outcomes in patients with acute ischemic stroke undergoing endovascular therapy. Methods— We reviewed demographic, clinical, procedural (GA versus local anesthesia [LA], etc), and site-adjudicated angiographic and clinical outcomes data from consecutive patients treated with the Solitaire FR device in the investigator-initiated North American SOLITAIRE Stent-Retriever Acute Stroke (NASA) Registry. The primary outcomes were 90-day modified Rankin Scale, mortality, and symptomatic intracranial hemorrhage. Results— A total of 281 patients from 18 centers were enrolled. GA was used in 69.8% (196/281) of patients. Baseline demographic and procedural factors were comparable between the LA and GA groups, except the former demonstrated longer time-to-groin puncture (395.4±254 versus 337.4±208 min; P =0.04), lower National Institutes of Health Stroke Scale (NIHSS; 16.2±5.8 versus 18.8±6.9; P =0.002), lower balloon-guide catheter usage (22.4% versus 49.2%; P =0.0001), and longer fluoroscopy times (39.5±33 versus 28±22.8 min; P =0.008). Recanalization (thrombolysis in cerebral infarction ≥2b; 72.94% versus 73.6%; P =0.9) and rate of symptomatic intracranial hemorrhage (7.1% versus 11.2%; P =0.4) were similar but modified Rankin Scale ≤2 was achieved in more LA patients, 52.6% versus 35.6% (odds ratio, 1.4 [1.1–1.8]; P =0.01). In multivariate analysis, hypertension, NIHSS, unsuccessful revascularization, and GA use (odds ratio, 3.3 [1.6–7.1]; P =0.001) were associated with death. When only anterior circulation and elective GA patients were included, there was a persistent difference in good outcomes in favor of LA patients (50.7% versus 35.5%; odds ratio, 1.3 [1.01–1.6]; P =0.04). Conclusions— The NASA Registry has demonstrated that clinical outcomes and survival are significantly better in patients treated with LA, without increased symptomatic intracranial hemorrhage risk. Future trials should prospectively evaluate the effect of GA on outcomes.

Rationale Self-expanding stent retrievers are a promising new device class designed for rapid flow restoration in acute cerebral ischaemia. The SOLITAIRE™ Flow Restoration device (SOLITAIRE) has shown high rates of recanalization in preclinical models and in uncontrolled clinical series. Aims ( 1 ) To demonstrate non-inferiority of SOLITAIRE compared with a legally marketed device, the MERCI Retrieval System®; ( 2 ) To demonstrate safety, feasibility, and efficacy of SOLITAIRE in subjects requiring mechanical thrombectomy diagnosed with acute ischaemic stroke. Design Multicenter, randomized, prospective, controlled trial with blinded primary end-point ascertainment. Study Procedures Key entry criteria include: age 22–85; National Institute of Health Stroke Scale (NIHSS) ≥8 and Outcomes The primary efficacy end-point is successful recanalization with the assigned study device (no use of rescue therapy) and with no symptomatic intracranial haemorrhage. Successful recanalization is defined as achieving Thrombolysis In Myocardial Ischemia 2 or 3 flow in all treatable vessels. The primary safety end-point is the incidence of device-related and procedure-related serious adverse events. A major secondary efficacy end-point is time to achieve initial recanalization. Additional secondary endpoints include clinical outcomes at 90 days and radiologic haemorrhagic transformation.

International audience; BACKGROUND AND PURPOSE:Mechanical thrombectomy is beneficial for patients with acute ischemic stroke and a proximal anterior occlusion, but it is unclear if these results can be extrapolated to patients with an M2 occlusion. The purpose of this study was to examine the technical aspects, safety, and outcomes of mechanical thrombectomy with a stent retriever in patients with an isolated M2 occlusion who were included in 3 large multicenter prospective studies.MATERIALS AND METHODS:We included patients from the Solitaire Flow Restoration Thrombectomy for Acute Revascularization (STAR), Solitaire With the Intention For Thrombectomy (SWIFT), and Solitaire With the Intention for Thrombectomy as Primary Endovascular Treatment (SWIFT PRIME) studies, 3 large multicenter prospective studies on thrombectomy for ischemic stroke. We compared outcomes and technical details of patients with an M2 with those with an M1 occlusion. All patients were treated with a stent retriever. Imaging data and outcomes were scored by an independent core laboratory. Successful reperfusion was defined as modified Thrombolysis in Cerebral Infarction score of 2b/3.RESULTS:We included 50 patients with an M2 and 249 patients with an M1 occlusion. Patients with an M2 occlusion were older (mean age, 71 versus 67 years; P = .04) and had a lower NIHSS score (median, 13 versus 17; P < .001) compared with those with an M1 occlusion. Procedural time was nonsignificantly shorter in patients with an M2 occlusion (median, 29 versus 35 minutes; P = .41). The average number of passes with a stent retriever was also nonsignificantly lower in patients with an M2 occlusion (mean, 1.4 versus 1.7; P = .07). There were no significant differences in successful reperfusion (85% versus 82%, P = .82), symptomatic intracerebral hemorrhages (2% versus 2%, P = 1.0), device-related serious adverse events (6% versus 4%, P = .46), or modified Rankin Scale score 0-2 at follow-up (60% versus 56%, P = .64).CONCLUSIONS:Endovascular reperfusion therapy appears to be feasible in selected patients with ischemic stroke and an M2 occlusion.

Background and Purpose: Recent randomized clinical trial (RCTs) demonstrated efficacy of mechanical thrombectomy using stent-retrievers in acute ischemic stroke (AIS) patients. The main purpose of TRevo ACute Ischemic StroKe (TRACK) stent-retriever thrombectomy multicenter registry is to demonstrate safety and efficacy in real life clinical practice. Methods: The investigator-initiated TRACK multicenter registry recruited 24 sites in north America to submit demographic, clinical, site-adjudicated angiographic, and outcome data on consecutive AIS patients treated with Trevo stent-retriever device as the first treatment option. Standard clinical safety (symptomatic intracranial hemorrhage (sICH), and mortality) and efficacy (revascularization and disability) outcomes and predictors of clinical outcome were analyzed. Results: 624 patients were enrolled in the TRACK registry. Median age was 68 years (range 16-94, 118 (18.1%) >80), male gender was 51.4%, and 67.7% were white. The median National Institutes of Health Stroke Severity Scale (NIHSS) was 17 (IQR 13-22). Transfer cases were 50.6% with IV-rtPA use in 318 cases (51.3%). Median onset to groin puncture (OTG) time was 283 min (IQR 198.5-443), and groin puncture to revascularization was 66 min (IQR 37.5-103). Anterior circulation occlusion was 86.2% (MCA/M2 in 55.2% followed by ICA in 15.9% and M2 in 12.7%). Use of GA was in 389 cases (62.3%), number of passes were ≤ 3 in 92% of the cases (1: 45.2%, 2:28%, and 3:18.7%), 291 (46.7%) had BGC use. Rescue use was seen in 21.7%. Revascularization of ≥ TIMI 2 was 81.8% and ≥ TICI 2b was 70%. The primary outcome of mRS of ≥ 2 was 48.3% in the full cohort, and 50.6% in TREVO-2 like group. sICH and mortality were 7.2%, and 20.1% in the full cohort vs 6.9% and 17.5% in the TREVO-2 like group, respectively. The independent predictors of clinical outcome were lower baseline NIHSS, younger age, use of BGC, successful recanalization, and no general anesthesia (GA). Conclusions: The real life clinical practice Trevo registry demonstrated good clinical outcome and high rate of recanalization. Younger age, lower baseline NIHSS, use of balloon guide catheter, successful recanalization, and avoiding endotrachaeal GA independent predictors of good clinical outcome.

We, as a group of international multi-disciplinary neurointerventional societies involved in the endovascular management of acute ischemic stroke, have put forth these training guidelines. We believe that a neuroscience background, dedicated neurointerventional training, and stringent peer review and quality assurance processes are critical to ensuring the best possible patient outcomes. Well-trained neurointerventionalists are a critical component of an organized and efficient team needed to deliver clinically effective mechanical thrombectomy for acute ischemic stroke patients.

Background: The Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial showed that patients with symptomatic 70% to 99% intracranial arterial stenosis are at particularly high risk of ipsilateral stroke on medical therapy: 18% at 1 year (95% CI = 3% to 24%). The Wingspan intracranial stent is another therapeutic option but there are limited data on the technical success of stenting and outcome of patients with 70% to 99% stenosis treated with a Wingspan stent. Methods: Sixteen medical centers enrolled consecutive patients treated with a Wingspan stent in this registry between November 2005 and October 2006. Data on stenting indication, severity of stenosis, technical success (stent placement across the target lesion with Results: A total of 129 patients with symptomatic 70% to 99% intracranial stenosis were enrolled. The technical success rate was 96.7%. The mean pre and post-stent stenoses were 82% and 20%. The frequency of any stroke, intracerebral hemorrhage, or death within 30 days or ipsilateral stroke beyond 30 days was 14.0% at 6 months (95% CI = 8.7% to 22.1%). The frequency of ≥50% restenosis on follow-up angiography was 13/52 (25%). Conclusion: The use of a Wingspan stent in patients with severe intracranial stenosis is relatively safe with high rate of technical success with moderately high rate of restenosis. Comparison of the event rates in high-risk patients in Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) vs this registry do not rule out either that stenting could be associated with a substantial relative risk reduction (e.g., 50%) or has no advantage compared with medical therapy. A randomized trial comparing stenting with medical therapy is needed. GLOSSARY: FDA = Food and Drug Administration; HDE = Humanitarian Device Exemption; ICH = intracerebral hemorrhage; WASID = Warfarin-Aspirin Symptomatic Intracranial Disease.

Background Pure subdural hematoma (without subarachnoid, intraventricular, or intraparenchymal hemorrhage) due to a rupture intracranial aneurysm is a rare pathology. Most reported cases involve an aneurysm along the internal carotid artery, posterior communicating artery, or middle cerebral artery. No reports have documented an aneurysm along the intracranial portion of a branch from the occipital artery. Case presentation Patient is a 70 year old female, history of hypertension, congestive heart failure, renal artery stenosis, gout, who presented with sudden onset severe excruciating headaches, associated with spinning sensation, nausea, and emesis. No history of trauma. Neurological examination was unremarkable. CT head demonstrated a tentorial subdural hematoma. CTA head revealed a 4 mm aneurysm along the peripheral left inferior cerebelllum and 3 mm aneurysm adjacent to the right sigmoid sinus, both without clear visualization of the parent vessels. Diagnostic angiogram revealed bilateral aneurysms along the transmastoid branches of the intracranial portion of both occipital arteries. Consequently, these branches were embolized, with no residual filling of the aneurysms. Post-procedure, she remained neurologically well. She was monitored appropriately for vasospasm, and discharged home 10 days after presentation. Conclusion Rupture of aneurysms along intracranial branches of the occipital artery can lead to pure subdural hematoma along the tentorium. For non-traumatic acute subdural hematoma, vigilance should be directed towards a vascular etiology. Disclosures H. Nguyen: None. N. Doan: None. S. Shabani: None. M. Gelsomino: None. O. Zaidat: None.

Stroke is the third leading cause of death in the USA, Canada, Europe, and Japan. According to the American Heart Association and the American Stroke Association, there are now 750 000 new strokes that occur each year, resulting in 200 000 deaths, or 1 of every 16 deaths, per year in the USA alone. Endovascular therapy for patients with acute ischemic stroke is an area of intense investigation. The American Stroke Association has given a qualified endorsement of intra-arterial thrombolysis in selected patients. Intra-arterial thrombolysis has been studied in two randomized trials and numerous case series. Although two devices have been granted FDA approval with an indication for mechanical stroke thrombectomy, none of these thrombectomy devices has demonstrated efficacy for the improvement of patient outcomes. The purpose of the present document is to define what constitutes adequate training to perform neuroendovascular procedures in patients with acute ischemic stroke and what performance standards should be adopted to assess outcomes. These guidelines have been written and approved by multiple neuroscience societies which historically have been directly involved in the medical, surgical and endovascular care of patients with acute stroke. The participating member organizations of the Neurovascular Coalition involved in the writing and endorsement of this document are the Society of NeuroInterventional Surgery, the American Academy of Neurology, the American Association of Neurological Surgeons/Congress of Neurological Surgeons Cerebrovascular Section, and the Society of Vascular & Interventional Neurology.

Background Advances in acute ischemic stroke mechanical thrombectomy devices have led to increased expectations of their safety and efficacy results. Objective To describe a new measure for the newer generation stroke thrombectomy devices, the First Pass Effect (FPE), defined as achieving thrombolysis in cerebral ischemia (TICI) score of 3 from the first pass, without the use of rescue therapy. In addition, a second objective was to assess if achieving TICI2b only with FP (FPE-TICI2b only) yielded similar results as FPE-TICI3 or non-FPE-TICI3 or non-FPE-TICI2b. The influence of FPE on clinical outcome, and its frequency and predictors was evaluated in the North American Solitaire Acute stroke (NASA) registry. Methods The FPE group was identified from the NASA multicenter registry database. Baseline features and clinical outcomeswere compared between the FPE group and the rest of the cohort. Subsequently, two multivariate analyzes were performed to identify if FPE is an independent predictor of clinical outcome and to identify the predictors of FPE. Furthermore, we assessed the difference between FPE and achieving other revascularization grades such as non-FPE-TICI3, FPE-TICI2b, and non-FPE-TICI2b scores. Clinical outcomes were mRS0–2 at 90 days, NIH stroke severity scale, mortality, and symptomatic intracranial hemorrhage (sICH). Results A total of 354 patients from 24 US centers were included in the NASA registry. The FPE was achieved in 89/354 (25.1%). Baseline demographics were comparable between FPE and the rest of the cohort, except that the FPE population had less octogenarians (34.6% vs. 65.4%), more woman (60.7% vs. 47.2%), and more Caucasians (83% vs. 71.2%). Baseline NIHSS and time from onset to groin puncture did not differ among the two groups. Angiographic features demonstrated more MCA occlusion (64% vs. 52.7%) and less ICA occlusion (10.1% vs. 27.7%) in the FPE group. Technical factors associated with FPE were limited to BGC use (64.8% vs. 36.8%), with no difference with use of IV-tPA, IA-tPA, or General Anesthesia. Multivariate analysis demonstrated use of BGC, no ICA occlusion, MCA occlusion, female gender, and white race as independent predictors of FPE. Clinical outcome measured with mRS 0–2 at 90 days was seen in 61.3%, 52.4%, 44.7%, and 39.1% with FPE-TICI3, FPE-TICI 2b, non-FPE-TICI3, and non-FPE-TICI2b, respectively. sICH was seen less frequently in FPE (5.6%,11.6%, 9.6%, and 12.9% in FPE-TICI3, FPE-TICI2b, non-FPE-TICI3,and non-FPE-TICI2b, respectively). Ninety days mortality was 16.3%, 31.0%, 27.7%, and 29.7% with FPE-TICI3, FPE-TICI2b, non-FPE-TICI3, and non-FPE-TICI2b, respectively. Conclusions The First Pass Effect was seen in 25.1% of NASA post-marketing registry patients and is the most powerful predictor of clinical outcome with best safety results. FPE is more commonly seen in white patients, MCA occlusion, and balloon guide catheter use; however, ICA terminus occlusion seems to be resistant to FPE. The FPE may also be related to gender, race, and age. Further research is needed to better understand the FPE and to guide future technical advances. Disclosures O. Zaidat: 1; C; Covidien, Stryker. 2; C; Covidien, Stryker. A. Castonguay: None. R. Gupta: None. C. Sun: None. C. Martin: None. W. Holloway: None. N. Mueller-Kronast: None. J. English: None. I. Linfante: None. G. Dabus: None. T. Malisch: None. F. Marden: None. H. Bozorgchami: None. A. Xavier: None. A. Rai: None. M. Froehler: None. A. Badruddin: None. T. Nguyen: None. M. Taqi: None. M. Abraham: None. V. Janardhan: None. H. Shaltoni: None. R. Novakovic: None. A. Yoo: None. A. Abou-Chebl: None. P. Chen: None. G. Britz: None. R. Kaushal: None. A. Nanda: None. R. Nogueira: None.

Background Real life practice can differ significantly from criteria in randomized clinical trials (RCT), including patient population, treatment criteria, and broader treatment times. Distinguishing device performance in these two different scenarios is critical in applying RCT data to routine clinical practice. Objective The TREVO Stent-Retriever Acute Stroke (TRACK) Registry aimed to assess the real-world safety, angiographic, and clinical efficacy of the TREVO device in comparison to the results from the TREVO-2 clinical trial. Design/methods The TRACK Registry recruited clinical sites within the USA. Demographic, clinical, angiographic, and outcome data on patients treated with the TREVO device were collected. Symptomatic intracranial hemorrhage (sICH) was defined as any parenchymal hematoma, SAH, or IVH associated with a worsening of the NIHSS score by≥4 within 24 h. The primary outcome was achieving TICI≥2a revascularization. Secondary outcomes were mRS at 3 months, mortality, and sICH. Results 23 centers contributed data on 586 patients for the final analysis. Baseline demographics were: 48.6% female, 68.3% white, mean age 65.8 ± 14.9 years, median baseline NIHSS of 17 (IQR 13–22), M1 (54.2%)/ICA(17.1%)/VB(13.7%) occlusion, IV-tPA use 50.4%, general anesthesia 63.2%, balloon guide catheter use 47.0%, mean fluoroscopic time 26.2 ± 22.1 min, and a median revascularization time of 65.5 (IQR 37–105.75) minutes. The TICI ≥2a and TICI ≥2b revascularization rates were 92.4% (537/581) and 80.4% (467/581), compared to the operator reported TICI ≥ 2a rate of 85% and core laboratory adjudicated TICI ≥2b of 68% in TREVO-2. Good outcome (mRS≤2) was demonstrated in 48.3% (240/497), compared to 40% (TREVO-2). The rate of sICH was 7.5% (43/574), compared to 4% (TREVO-2). 90-day mortality was 20.1% (100/497) versus 29% in TREVO-2. Multivariate logistic regression analysis demonstrated that younger patients, lower baseline NIHSS, revascularization success (TICI ≥2B), and use of conscious sedation were independent predictors of good clinical outcome. Independent predicators of mortality included older patients, higher baseline NIHSS, vertebral-basilar occlusion, lack of IV-tPA use, failure to achieve revascularization, and sICH. Conclusion The investigator-initiated TRACK Registry demonstrates that the post-marketing TREVO stent-retriever performance in routine clinical practice is comparable to the TREVO-2 trial, with improved revascularization success, good outcome, and decreased mortality. Disclosures O. Zaidat: 1; C; Stryker, Covidien. 2; C; Stryker, Covidien. A. Castonguay: None. R. Nogueira: None. P. Ramakrishnan: None. D. Haussen: None. A. Lima: None. J. English: None. H. Farid: None. E. Veznedaroglu: None. M. Binning: None. A. Puri: None. S. Hou: None. V. Janardhan: None. N. Vora: None. R. Budzik: None. A. Alshekhlee: None. M. Abraham: None. R. Edgell: None. M. Taqi: None. E. Lin: None. R. Khoury: None. M. Mokin: None. A. Majjhoo: None. M. Kabbani: None. M. Froehler: None. I. Finch: None. S. Prabhakaran: None. R. Novakovic: None. T. Nguyen: None. J. Wesley: None.

Background Early intra-arterial therapy achieves good functional outcome in 32%–70% of patients with acute ischemic stroke due to large vessel occlusion. While timely recanalization has been shown to be the prototype predictor for good outcome, other factors that might affect recovery in those patients are not well documented. Method A single center database review identified stroke patients who underwent intra-arterial therapy with successful final recanalization defined as TICI 3 or TICI 2b. Demographic, clinical, radiographic, and procedural variables of these patients were included in logistic statistical analysis using t-test and Chi-square test to study their effects on functional outcome as described by mRS score at 3 months. Results Out of 296 patients treated with intra-arterial therapy, 129 (43.5%) had successful recanalization and were included in our analysis. Of those patients, 68 (52.7%) had good functional outcome defined as mRS 0–2, and 55 (42.6%) had poor outcome (mRS >2). Six patients were lost to follow-up. Mean age of the patients was 63 years, and mean NIHSS score was 16. Onset to groin puncture average time was 352 min, while the mean procedure duration was 108 min. When compared to those who had poor outcome, patients who had good functional outcome were younger (mean age 59 years compared to 66 years, p 0.0116), and had less severe stroke (mean NIHSS score 13 compared to 19, p On multivariate analysis; age (p 0.001), NIHSS score (p Conclusion Age, NIHSS score, use of stent retrievers, mode of anesthesia, and symptomatic ICH might affect functional outcome in stroke patients who achieve successful recanalization via intra-arterial therapy. Prospective studies, or a meta-analysis of sub-groups in the recently published prospective trials are needed to confirm the association between those factors, or others, and functional outcome. Identification of such predictors might help in screening acute stroke patients for intra-arterial therapy. Disclosures M. Noufal: None. J. Mankad: None. D. Shirilla: None. A. Lakraj: None. J. Cox: None. A. Sattar: None. W. Wally: None. Y. Sallowm: None. J. Lynch: None. O. Zaidat: None.

Background The MR CLEAN multicenter randomized clinical trial demonstrated the safety and effectiveness of intra-arterial treatment within 6 h after stroke onset in patients with acute ischemic stroke (AIS) caused by proximal intracranial occlusion in the anterior circulation. Objective To present the clinical and angiographic outcomes of a MR CLEAN-like population within the real-world multicenter TREVO Stent-Retriever Acute Stroke (TRACK) Post-marketing Registry and assess its performance relative to the MR CLEAN population. Design/methods The investigator-initiated TRACK Registry recruited sites within North America to submit retrospective data on consecutive patients treated with the TREVO device. A TRACK sub-cohort matched to the MR CLEAN interventional population (based on the following criteria: anterior circulation occlusion, time of onset to groin puncture ≤6 hrs, NIHSS ≥2) was identified (TRACK-MRCL) and compared to the MR CLEAN interventional and control (MRC-I, MRI-C) group of 233 and 267 patients, respectively. The groups were evaluated for differences in the clinical (mRS at 3 months, mortality, and sICH) and angiographic outcomes (TICI revascularization grades). Results 409 patients underwent treatment using the TREVO device in 18 centers. Of those patients, 250 patients were included in the TRACK-MRCL group. Demographics of the TRACK-MRCL, MRC-I, and MRC-C groups (respectively): median age (IQR) 69 (55–78) versus 65.8 (54.5–76.0), and 65.7 (55.5–76.4); median NIHSS (IQR) 18 (14–22) versus 17 (14–21), and 18 (14–22); male 49.2% vs. 57.9%, and 58.8%, p = 0.12; ICA occlusion 20.4% vs. 25.3%, and 28.2%, p = 0.19; M1 occlusion 59.2% vs. 66.1%, and 62%, p = 0.13; IV-tPA use 67.2% vs. 87.1%, 90.6%, p = 0.0001; general anesthesia use 65.5% vs. 37.5%, p = 0.0001; median time of onset to groin puncture (min) (IQR) 215 (169.8–268.5) versus 260 (210–313). TICI ≥ 2a and TICI ≥ 2b revascularization rates were 92.8% vs. 80.6% (p = 0.0002) and 83.6% vs. 58.7% (p = 0.0001) in the TRACK-MRCL and MRC-I groups, respectively. sICH was noted in 8.5% of TRACK-MRCL patients compared to 7.7% and 6.4% in the MRC-I and MRC-C groups, respectively (p = 0.87). In TRACK-MRCL patients with available 90-day outcomes, 47.3% (113/239) had achieved a good clinical outcome (mRS 0–2) versus 32.6% (76/233) and 13.1% (35/267) in the MRC-I and MRC-C groups, respectively (p = 0.0014). Mortality was 14.2% (34/239) in the TRACK-MRCL cohort versus 9.0% (21/233) and 8.2% (22/267) in the MRC-I and MRC-C groups, respectively (p = 0.09). Conclusion Although not directly comparable, this sub-analysis of a real-world TREVO stent-retriever registry patient matched to MR CLEAN population demonstrated consistent higher rates of good clinical and revascularization outcomes than the MR CLEAN control group. Disclosures A. Castonguay: None. O. Zaidat: None. R. Nogueira: None. P. Ramakrishnan: None. D. Haussen: None. A. Lima: None. J. English: None. H. Farid: None. E. Veznedaroglu: None. M. Binning: None. A. Puri: None. S. Hou: None. V. Janardhan: None. N. Vora: None. R. Budzik: None. A. Alshekhlee: None. M. Abraham: None. R. Edgell: None. M. Taqi: None. E. Lin: None. R. Khoury: None. M. Mokin: None. A. Majjhoo: None. M. Kabbani: None. M. Froehler: None. I. Finch: None. S. Prabhakaran: None. R. Novakovic: None. T. Nguyen: None.

Introduction Giant intracranial aneurysms present a danger of hemorrhage, mass effect, and thromboembolism. Fusiform or wide-necked aneurysms not amenable to clipping or coiling can be sometimes treated by indirect trapping or by deployment of a flow-diverter device. Such interventions are aimed at reducing the flow through the aneurysm in the hope that this would inhibit its progression. Patient-specific computational models based on medical imaging data can predict postoperative flow fields resulting from alternative interventional options and thus may help avoid complications related to thrombotic occlusion of distal arteries emanating from the aneurysmal vessel. Methods Contrast-enhanced MR angiography data acquired prior to intervention were used to generate computational fluid dynamics (CFD) models of the preoperative geometries. The inflow conditions were measured in the proximal arteries with 2D phase-contrast MRI. Preoperative flow computations were validated in comparison to in vivo 4D Flow MRI measurements, providing time-resolved flow fields. The models were modified according to the proposed interventions, e.g. clipping of proximal or distal vessels and adding bypasses, or deploying flow-diverter devices. Postoperative flows were computed and used to simulate transport of a virtual contrast agent. This allowed evaluation of the changes in filling and washout times caused by different interventions. Results We illustrate this approach with retrospective analyzes of two intracranial aneurysms. In the first case, a fusiform basilar aneurysm was treated by placing a clip across the superior cerebellar arteries, leaving one SCA attached to the basilar apex and the other to the basilar trunk. A bypass was performed to supply the basilar apex from the anterior circulation. The CFD model showed that this intervention would result in substantial increase of the flow residence time in the distal basilar trunk (Figure 1). This indicated a high likelihood of pontine perforators thrombosis, which was observed following the procedure. In the second case, a giant internal carotid aneurysm was treated by placing a flow-diverter. The image-based computational model incorporated the device modeled as a porous tube. The flow field predicted with CFD (Figure 2a) is in agreement with that measured postoperatively with 4D Flow MRI (Figure 2b) and show a region of slow, recirculating flow with increased washout time which will facilitate thrombotic occlusion of the lesion. Conclusions The study indicates that computational models constructed from medical imaging data can be used to predict postoperative flow in cerebral aneurysms. This information, available prior to intervention, may help improve the outcome of surgical procedures. Disclosures V. Rayz: 1; C; NHLBI R01 HL115267. O. Zaidat: None. V. Halbach: None. D. Saloner: None. M. Lawton: None.

Background With the presentation of the MR CLEAN, EXTEND IA, ESCAPE and SWIFT PRIME trials at ISC 2015, treatment of proximal large vessel occlusion with stent retrievers within of 6–12 hrs of stroke onset has become standard of care. The results of these trials greatly depended on their efficient triage and safe technique and there is only limited data on how these results may be replicated in the community. Method STRATIS is the first prospective registry to track patients treated with a Solitaire™ stent retriever as first modality. The registry has three unique design aspects that distinguish it from other studies. The registry has independent core lab validation of imaging outcomes, and as a first, documents the impact of 6 forms of interventional techniques as well as type of anesthesia on the 90 day outcome. Moreover, the potential for large cohort of physiological perfusion images use for triage will be available from STRATIS Registry. Furthermore, it tracks the well-needed system of care data including transfer distances, referral patterns, times and location of stroke onset to ultimate interventional treatment. STRATIS will be the largest registry to date with this level of granular detail with intent to enroll 1000 patients within 8 hrs from onset to groin puncture in 60 sites, 27 of which will be former SWIFT PRIME sites. Results 124 subjects have been enrolled at 23 centers, with a mean age of 68.4 (19, 100) and median baseline NIHSS 16.6 (8, 30). 54% received IV tPA at a mean time of 119 min from onset. Mean onset to groin time was 266 mins. Distribution of occlusions with 16% combined extra- and intra-cranial ICA, 63% M1 and 18% M2 emboli was similar to the SWIFT PRIME. 50% underwent advanced imaging with CTP. Site-reported successful reperfusion (mTICI 2b-3) was achieved in 81.4%. sICH occurred in only 0.8% (1/124) of patients. Conclusion In a limited cohort that is similar to the population as descried in the published trials, STRATIS is documenting achievement of equivalent reperfusion and safety endpoints. However, despite similar onset to IV tPA time, onset to groin puncture time was significantly longer in the community setting. The detailed system of care analysis of STRATIS should allow sites to identify gaps to improve triage strategies. The detailed procedural documentation should, for the first time, be able to delineate the impact of anesthesia and different interventional techniques on patient outcomes. Disclosures N. Mueller-Kronast: 2; C; Covidien Neurovascular. A. Aziz-Sultan: 2; C; Covidien Neurovascular. R. Jahan: 2; C; Covidien Neurovascular. R. Klucznik: 2; C; Covidien Neurovascular. O. Zaidat: 2; C; Covidien Neurovascular.

Purpose Final ASPECTS score is a good predictor of patient outcomes after intra-arterial therapy for acute ischemic stroke. The purpose of this study was to compare sequential pre- and post-treatment ASPECTS imaging in predicting outcome. Methods The PICS Study was a registry of clinical and imaging data from patients with proximal artery occlusion treated by the Penumbra System. A central core laboratory, blinded except for knowledge of the stroke side, determined the ASPECTS scores. The univariate relationship between 90 day mRS (0–6) and age, baseline NIHSS, discharge to 7 day NIHSS, as well as pre- and post-treatment ASPECTS (0–10) and ASPECTS change was evaluated with the Spearman’s correlation coefficient. Variables with significance of p Results Within the study, 142 patients met inclusion criteria for this analysis, with a mean age of 67.8 ± 15.5 and median admission NIHSS score of 16.0 (IQR 12.0–21.0). Logistic regression analysis was utilized to evaluate the impact of covariates on 90-day good outcome (mRS 0–2). After adjusting for age and baseline NIHSS, post-treatment ASPECTS showed a stronger relationship with good outcome (Large Odds Ratio 0.20; p = 0.0063) than pre-treatment ASPECTS (Large Odds Ratio 0.33; p = 0.24). Post-treatment worsening in ASPECTS was also a significant predictor of 90 day mRS (Odds Ratio 0.75 per 1 point worsening; p = 0.047) in the multivariate analysis. Conclusion Overall, sequential and post-procedure ASPECTS were better indicators of clinical outcome following intra-arterial therapy than pre-ASPECTS. Final infarct volume measured using ASPECTS could aid as a surrogate biomarker for long-term functional outcome, and ASPECTS decline may serve as a biomarker for procedural effectiveness. Disclosures A. Yoo: 1; C; NIH, Penumbra, Inc., Remedy Pharmaceuticals. O. Zaidat: 1; C; Penumbra, Inc.. 2; C; Stryker, Gore Medical. 4; C; Galaxy Therapeutics. Z. Chaudhry: None. O. Berkhemer: None. R. Gonzalez: None. M. Goyal: None. A. Demchuk: None. B. Menon: None. E. Mualem: 5; C; Penumbra, Inc. H. Buell: 5; C; Penumbra, Inc. S. Kuo: 5; C; Penumbra, Inc. S. Sit: 4; C; Penumbra, Inc.. 5; C; Penumbra, Inc. A. Bose: 4; C; Penumbra, Inc.. 5; C; Penumbra, Inc..

There are only limited epidemiological studies evaluating the association between vertebrobasilar dolichoectasia (VBD) and outcomes. This study was designed to elucidate the outcome and prognosis of adults diagnosed with VBD by magnetic resonance angiography (MRA) and to ascertain if these outcomes were independent of known vascular risk factors.A cohort study was designed to compare VBD cases identified retrospectively from a computerised database of MRA reports with age and sex matched controls evaluated after a 4-7 year period, and 1440 MRA reports were reviewed. The inclusion criteria were ageor =18 years and a radiological diagnosis of VBD. Patients were excluded if there was haemodynamically significant stenosis or occlusion of the posterior circulation. Data were obtained by medical record review and telephone questionnaires. The primary outcome measure was transient or fixed posterior circulation dysfunction (PCD), with a secondary outcome measure of all cause mortality.Sixty four VBD cases were obtained, and 19 cases (30%) were excluded due to refusal and/or insufficient follow up data. From the same computerised database, 45 controls were selected by consecutive sampling. The mean age at follow up was 73.4 years for VBD cases and 73.1 years for controls, with a median follow up period of 64 months. VBD was associated with fixed/transient PCD (p = 0.0001; estimated adjusted odds ratio (OR) of 20.6 and confidence interval (CI) of 4.4 to 95.3), and with all cause mortality (OR = 3.6 CI 1.3 to 10.3); (p = 0.018). VBD cases had 36% mortality, with 50% occurring within 34 months of the initial diagnosis. The VBD cumulative survival curve was statistically different from the controls (p = 0.012 by Mantel-Cox log rank test).This study suggests that VBD may be an independent risk factor for stroke. VBD cases had an increased likelihood for PCD, all cause mortality, and reduced cumulative survival independent of other vascular risk factors in this cohort. Larger population based prospective studies are required to verify these results.

Background The anterior communicating (ACom) artery is the most common location of cerebral aneurysms harbouring upto 30–37% of all treated aneurysms. Amongst all ruptured aneurysms, the proportion of patients with very small aneurysms ranges from 12–18%. Treatment of very small aneurysms ( Objective To report the immediate and long-term clinical as well as radiographic outcomes of consecutive patients with ruptured very small anterior communicating artery (ACOM) aneurysms treated with endovascular technique. Methods A prospectively maintained single institution neuro-endovascular database was accessed to identify consecutive cases of very small ( Results A cohort of 20 consecutive patients with ruptured very small ( Conclusion Endovascular treatment of very small ACom aneurysms can be performed with acceptable rates of complications and recanalization. Robust conclusions can be drawn only after further evaluation with larger number of patients and longer follow-up. Disclosures K. Asif: None. M. Teleb: None. A. Sattar: None. M. Lazzaro: None. B. Fitzsimmons: None. J. Lynch: None. O. Zaidat: None.

Background and purpose Intracranial stenting and angioplasty has been increasingly utilized for the treatment of symptomatic intracranial atherosclerotic disease (ICAD). The use of self-expanding stents (SES) has been reported to have a high technical success rate but there are concerns with restenosis. We sought to determine if the use of balloon mounted stents (BMS) was associated with higher technical complication rates compared with self-expanding stents. Methods Three academic institutions contributed data on patients treated for symptomatic ICAD over a 3 year period (2006–2009). 259 consecutive patients were identified. Demographics, type of stent placed, periprocedural complications, per cent stenosis prior to treatment and after treatment, if the treatment was within 2 weeks of clinical symptomatology, lesion classification with the Mori scale and follow-up imaging for restenosis were collected retrospectively. A univariate analysis was performed to determine predictors of periprocedural stroke and also for restenosis at follow-up. Variables with a p value Results 259 patients with a mean age of 61±13 years with 168 (65%) patients presenting with strokes and the rest with transient ischemic attacks. The distribution of the lesions were as follows: vertebrobasilar 109 (42%), middle cerebral artery 85 (33%) and intracranial internal carotid artery 65 (25%). 79 (31%) BMS were implanted and 180 (69%) SES. A total of 17 (6.5%) patients developed a periprocedural stroke with no difference noted between use of type of stent. Patients in whom a BMS was implanted had a significant reduction in stenosis compared with SES (81±10% to 7±11% vs 80±12% to 24±9%; p Conclusions The use of BMS was not associated with higher complication rates but was associated with lower restenosis rates. Placement of stents in patients with more complex lesions is associated with higher periprocedural stroke rates and restenosis. Further prospective studies comparing BMS with SES are warranted.

Background and purpose The use of endovascular techniques to treat large artery occlusion in acute ischemic stroke has become more frequently employed as a treatment option. We sought to determine the predictors of intracranial hemorrhage after these procedures were performed. Methods This is a retrospective review of data from 13 high volume stroke centers that perform endovascular treatments for acute ischemic stroke. Patients with anterior circulation strokes treated under 8 h from symptom onset with endovascular therapy were included. Hemorrhages were classified as parenchymal hematoma (PH) types 1 and 2 and hemorrhagic infarction (HI) types 1 and 2. Patients with PH bleeds were considered symptomatic and HI bleeds were asymptomatic. Binary logistic regression modeling was performed to determine the variables associated with symptomatic and asymptomatic hemorrhages after correcting for multiple comparisons. Results A total of 1122 patients met the inclusion criterion for this study. Mean age for the cohort was 67±15 years with a median National Institutes of Health Stroke Scale (NIHSS) of 17 (IQR 13–20). The distribution for thrombus location at the initiation of endovascular therapy was as follows: M1 segment of the middle cerebral artery (MCA) 561 (50%), carotid terminus 214 (19%), M2 MCA 171 (15%), tandem occlusions 141 (13%) and isolated extracranial internal carotid artery occlusion 35 (3%). Parenchymal hematomas occurred in 96 (8.5%) patients and HI in 265 (24%) patients. There were no variables associated with symptomatic hemorrhages while the following variables were predictors of asymptomatic hemorrhage: diabetes mellitus (OR 2.02; 95% CI 1.46 to 2.79; p Conclusions Diabetic patients and those who have been treated with intravenous tPA prior to the procedure or intraprocedural use of thrombolytics or the Merci device appear to be at a higher risk for asymptomatic hemorrhage. Moreover, patients with asymptomatic hemorrhage appear to be at a higher risk for a worse clinical outcome at the 90 day follow-up.

Objective: CT angiography (CTA) has recently gained popularity for detection of stenotic and occlusive diseases in intracranial and neck vessels. With 3D reconstruction, CT angiogram can provide reasonably reliable estimates of vascular pathology. We wanted to look at the sensitivity and specificity of CTA in evaluating atherosclerotic diseases of the head and neck …

The clinical effect of carbamazepine (CBZ) on neuromuscular transmission is described in two children who presented in coma with diffuse hypotonia and areflexia following CBZ overdose. Repetitive nerve stimulation (RNS) showed a decremental response only at high-frequency stimulation. With supportive care, the patients made an uneventful recovery. Follow-up RNS was normal. This is the first report of a clinically evident neuromuscular transmission defect produced by CBZ. We postulate that CBZ's known effect on decreasing sodium channel depolarization produced a defect in neuromuscular transmission. The report emphasizes the contribution of RNS in the evaluation of coma of uncertain etiology, particularly in cases of possible intoxication, and the potential for CBZ to compromise neuromuscular transmission in normal individuals or in patients with a decreased neuromuscular transmission safety factor.

Eighteen patients underwent stenting for symptomatic basilar artery stenosis. There were three major periprocedural complications (16.7%) without fatality. At a mean 26.7 ± 12.1-month follow-up, 15 patients (83.3%) had an excellent long-term outcome. Only one patient (5.6%) had moderate disability from recurrent stroke, and two patients died of medical illness at 30 and 36 months after stenting. In this uncontrolled study, stenting appeared to be effective in reducing stroke risk and death and worthy of further scrupulous trial.

Introduction/Purpose The Penumbra START Trial is a multicentre, prospective, single-arm trial with a primary aim of determining whether core infarct size on pre-treatment neuroimaging predicts clinical response to intra-arterial acute stroke therapy. Materials and Methods For this study, major inclusion criteria include presence of proximal artery occlusion in the anterior circulation, baseline NIHSS score of 10 or greater, evaluable pre-treatment neuroimaging [noncontrast CT (NCCT), CTA source imaging, CT perfusion or MRI DWI], and treatment with the Penumbra System within 8 hours. Core infarct size was evaluated by a blinded imaging Core Laboratory. As pre-specified, infarcts were trichotomised into small [ASPECTS 8–10 (NCCT, CTA-SI) or lesion volume 100 cc). In total, 146 patients were enrolled at 27 centres, including 104 patients with Core Lab review and evaluation at 90 days. Good clinical outcome is defined as mRS 0–2 at 90 days. Case review is still ongoing, and statistical analysis is from the 104 patients with complete information. We will update results at the time of the meeting. Results Mean age is 66 ± 14, including 56% females. Median baseline NIHSS score is 19 (IQR14–22), and 58% of patients had occlusions located on their left side. Overall, TIMI 2–3 revascularisation was achieved in 85%. Forty-eight patients had a good outcome at 90 days (46%); 28 patients died (27%). The number of evaluable scans for each imaging method was: 31 CTP, 82 CTA-SI, 79 NCCT, and 6 DWI. After pooling all modalities in an aggregate analysis, a statistically significant relationship was found between core infarct size and good outcome, such that worse outcomes were found only in the large infarct group. The rate of 90-day good outcome was 54% in small, 56% in medium, and 19% in large infarcts (p=0.0010), despite similar rates of recanalisation (79% small, 93% medium, 84% large). Independent predictors of good outcome were age, baseline NIHSS score, time from onset to recanalisation, and infarct volume. Thirteen patients experienced symptomatic ICH (13%). Conclusion Pre-treatment neuroimaging is important in identifying patients with large infarcts who are unlikely to respond to mechanical thrombectomy. These data support the use of rigorous imaging criteria in patient selection. Disclosures D. Frei: 3; C; Penumbra, Inc. A. Yoo: 1; C; Penumbra, Inc. D. Heck: None. F. Hellinger II: None. V. McCollom: None. D. Fiorella: None. A. Turk III: 3; C; Penumbra, Inc. T. Malisch: None. O. Zaidat: 1; C; Penumbra, Inc. 3; C; Penumbra, Inc. M. Alexander: None. Z. Chaudhry: None. R. Gonzalez: None. L. Barraza: 5; C; Penumbra, Inc. A. Bose: 4; C; Penumbra, Inc. 5; C; Penumbra, Inc. S. Sit: 5; C; Penumbra, Inc. 6; C; Penumbra, Inc.

Introduction Efficient and timely recanalisation is an important goal in acute stroke endovascular therapy. Several studies have shown improved recanalisation and clinical outcomes with the Stentriever devices compared to the MERCI device. The goal of this study was to evaluate the role of the balloon guide catheter and recanalisation success in a sub-study of the North American Solitaire Stent-Retriever Acute Stroke Registry (NASA). Methods The investigator-initiated NASA Registry recruited 24 clinical sites in North America to submit demographic, clinical, site-adjudicated angiographic and clinical outcome data on consecutive patients treated with the Solitaire FR device (Covidien). Balloon guide catheter was used at the discretion of the treating physicians. Results There were 354 patients included in this study. Data of BGC use was not reported in 16 patients, leaving 338 patients in this sub-analysis, of which 149 (44%) had placement of the BGC. Mean age was 67.3+15.2 years and median NIHSS was 18. Patients with BGC had more hypertension (82% vs 73%; p=0.05), atrial fibrillation (51% vs 33%; p=0.001) and were more commonly administered tPA (51% vs 39%; p=0.02) compared to patients without BGC. Time from symptom onset to groin puncture and number of passes were similar between the two groups. Procedure time was shorter in patients with BGC (120 vs 161 minutes, p=0.02) and less rescue therapy was used in patients with BGC (20% vs 28.6%, p=0.05). TICI 2b/3, TICI 3 recanalisation was higher in patients with BGC compared to patients without (TICI 2b/3: 75% vs 70%; TICI 3 53% vs 32.5% p>0.001). Distal emboli and emboli in new territory were similar between the two groups. Discharge NIHSS (mean 12 vs 17.5; p=0.002) and good clinical outcome at 3 months were superior in patients with BGC compared to patients without (51.6% vs 35.8%; p=0.02). In multivariate analysis, initial NIHSS, use of general anaesthesia and BGC were independent predictors of good clinical outcome. Conclusion Use of a balloon guide catheter with the Solitaire Stent retriever in acute ischaemic stroke results in superior recanalisation results, faster procedure time, decreased need for rescue therapy, and improved clinical outcome. Disclosures T. Nguyen: 2; C; Penumbra, THERAPY Trial DSMB/ CEC. T. Malisch: None. A. Castonguay: None. R. Gupta: None. C. Sun: None. C. Martin: None. W. Holloway: None. N. Mueller-Kronast: None. I. Linfante: None. G. Dabus: None. F. Marden: None. H. Bozorgchami: None. A. Xavier: None. A. Rai: None. A. Badruddin: None. M. Taqi: None. M. Abraham: None. H. Shaltoni: None. V. Janardhan: None. A. Abou Chebl: None. P. Chen: None. A. Yoo: None. R. Nogueira: None. A. Norbash: None. O. Zaidat: None.

Introduction/Purpose The recent results of the SWIFT and TREVO-2 trials demonstrated better recanalisation and efficacy rates with mechanical thrombectomy; however, its efficacy in the elderly population is poorly understood. Here, we report the effect of age on clinical and angiographic outcome within the North American SOLITAIRE-FR Stent-Retriever Acute Stroke (NASA) Registry. Methods The investigator-initiated NASA Registry recruited sites within North America to submit data on consecutive patients treated with Solitaire-FR. Good clinical outcome was defined as a 90-day mRS ≤2. Successful recanalisation was defined as TIMI ≥2. SICH was defined as any parenchymal haematoma, SAH, or IVH associated with a worsening of the NIHSS score by 4 or more within 24 hours. Age influence on outcomes was assessed by comparing the means between outcomes and dichotomising the age into ≤80 or ≥80 years of age. A standard medical care cohort was not available for comparison in this study. Results 343 patients underwent treatment using the SOLITAIRE-FR device in 24 centres. The mean age for those with good clinical outcome at 90 days was 64.9 ± 15 versus 69.2 ± 14.4 years (P=0.02). Only 26.6% (17/64) of patients >80 years of age had a 90-day mRS ≤ 2 versus 45.3% (111/245) of those ≤80 years of age (p=0.007, OR 1.34, 95%CI 1.2-1.6). Mortality was 42.2% (27/64) and 27.4% (67/245) in the >80 and ≤80 age groups, respectively. No difference in good outcome or mortality between female and males was observed in this population (90-day mRS≤ 2 was 41.3% (62/150) with mortality of 28% (42/150) versus 42.1% (69/164) with mortality of 32.3% (53/164) in females and males, respectively). Multivariate logistic regression analysis (adjusting for age, sex, race, baseline-NIHSS, occlusion site, initial BP, time from symptoms onset to groin puncture, and revascularisation), showed age, baseline-NIHSS, initial systolic blood pressure and revascularisation status as an independent predictors of both good outcome and mortality. Conclusions In the NASA registry, patients >80 years of age who were treated with the Solitaire-FR device demonstrated a significantly lower rate of good clinical outcome and increased mortality at 90-days, compared to the those in the ≤ 80 years of age group. Disclosures A. Castonguay: None. R. Gupta: None. R. Nogueira: None. C. Martin: None. W. Holloway: None. N. Mueller-Kronast: None. T. Malisch: None. F. Marden: None. H. Bozorgchami: None. A. Xavier: None. A. Rai: None. A. Badruddin: None. M. Taqi: None. I. Linfante: None. G. Dabus: None. M. Abraham: None. H. Shaltoni: None. V. Janardhan: None. T. Nguyen: None. A. Abou-Chebl: None. P. Chen: None. A. Yoo: None. G. Britz: None. A. Nanda: None. O. Zaidat: None.

Introduction/Purpose Literature indicates that recanalisation with IV rtPA therapy is more likely when clot length is ® as adjuvant treatment to IV rtPA in stroke patients with large vessel occlusions and extensive clot burdens in the anterior circulation. Materials and Methods THERAPY is a prospective, randomised, multicentre, concurrent controlled study. Patients from 18 to 85 yo [n=692] presenting with acute ischaemic stroke symptoms, an NIHSS score of ≥8 and IV rtPA-eligible with evidence of a clot length 8mm or longer in the anterior circulation from reconstructed thin-sliced NCCT are randomised 1 to 1 to IV rtPA therapy alone or combined IV rtPA therapy and adjunctive treatment with the Penumbra System. The primary endpoints are 90-day good functional outcome and incidence of serious adverse events. Secondary endpoints include good functional and neurological outcomes at discharge and 30 days, and the incidence of ICH. An independent Core Lab will review imaging data, while a CEC/DSMB will adjudicate safety. A preliminary analysis of the reasons for screened failures in IV rtPA-eligible patients indicates the following top criteria for exclusion (see pie chart): NIHSS score 85. Reasons for being unable to obtain consent include shipped from outside institution and/or outside time window to consent (45%), refused consent (9%), no family member present to consent (6%), and no reason provided by the site (40%). In patients who had clot length assessed, roughly 75% meet the criterion of ≥8mm clot length. Results Approximately 47 centres have committed to THERAPY, of which 41 have received IRB approval. To date, 29 centres have been initiated, and 33 patients are randomised. Conclusion In keeping with the findings from the IMS III Trial, the randomised, prospective, controlled THERAPY trial may serve as the seminal study to clearly define the role of mechanical thrombectomy in an acute ischaemic stroke cohort who are unlikely to respond to IV rtPA and may benefit from an IV-IA bridging approach. Disclosures J. Mocco: 1; C; Penumbra, Inc. 3; C; Penumbra, Inc. P. Khatri: 1; C; Penumbra, Inc. O. Zaidat: 1; C; Penumbra, Inc. 3; C; Penumbra, Inc.

Introduction/Purpose IMS3 demonstrated no significant difference between treatment with IV-rtPA alone or IV-rtPA plus IA therapy. However, the trial included only earlier generations of thrombectomy devices and did not evaluate the efficacy of newer devices. Here, we present data on an “IMS-III-Like group” from The North American SOLITAIRE Acute Stroke (NASA) Registry, a repository database of the newer generation Solitaire Stent-retriever. An exploratory analysis was performed to compare these results to the IMS3 IV and IV/IA groups. Materials and Methods The investigator-initiated NASA Registry recruited sites to submit data on consecutive patients treated with Solitaire-FR. A cohort similar to the IMS-III IV-rtPA+Solitaire-FR population (NASA-IMS3 Matched Group (NIMG)) was identified and compared to the recently published results of the IMS3 IV and IV/IA groups. Good clinical outcome was defined as a 90-day mRS ≤2. Successful recanalisation was defined as TIMI ≥2. SICH was defined as any parenchymal haematoma, SAH, or IVH associated with a worsening of the NIHSS score by 4 or more within 24 hours. Results 354 acute ischaemic stroke patients were enrolled in the NASA Registry from 24 centres. The cohorts were comprised of: 156 NIMG versus 434 and 222 in the IMS3 IV/IA and IV only groups, respectively. Baseline demographics were similar between cohorts: Median age 70 (NIMG); 69 (IMS3 IV/IA); 70 (IMS3 IV). Initial median NIHSS was higher in NIMG (19) compared to the IMS3 IV/IA (17) and IMS3 IV groups (18). mTICI > 2b rate was 69.9% in NIMG versus 39.6% in the IMS III IV/IA. Interestingly, mTICI 3 rate was 41% in NIMG vs 2.2% in the IMS III IV/IA group. The 90-day mRS outcome was available in 88.5% (138/156) of NIMG patients. A good outcome of mRS?2 was demonstrated in 51.5% (71/138), compared to 40.8% (169/415) in IMS3 IV/IA and 38.7% (83/215) in IM3 IV alone groups. 90-day mortality was 24.6% in NIMG versus 19.1% and 21.6% in IMS3 IV/IA and IV alone groups, respectively. Conclusion In the NASA registry, the NASA-IMS3 Matched Group (NIMG) demonstrated a higher rate of good clinical outcome (51.5%) compared to the IMS3 IV/IA (40.8%) and IV alone (34.6%) groups. Disclosures R. Nogueira: None. A. Castonguay: None. R. Gupta: None. C. Sun: None. C. Martin: None. W. Holloway: None. N. Mueller-Kronast: None. J. English: None. I. Linfante: None. G. Dabus: None. T. Malisch: None. H. Bozorgchami: None. A. Xavier: None. A. Rai: None. M. Froehler: None. A. Badruddin: None. T. Nguyen: None. M. Taqi: None. M. Abraham: None. V. Janardhan: None. H. Shaltoni: None. A. Yoo: None. A. Abou-Chebl: None. P. Chen: None. O. Zaidat: None.