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Introduction: While the goal of IV tissue plasminogen activator (TPA) is to prevent infarction, few data exist on averted stroke. Methods: Secondary analysis of a multicenter trial from 2014-2020 comparing outcomes between patients treated for stroke by mobile stroke unit (MSU) vs standard care (SC). The analytical cohort were patients with suspected stroke treated with IV TPA. The primary outcome was a time-defined averted stroke diagnosis, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours. The secondary outcome was a tissue-defined averted stroke diagnosis, defined as a final diagnosis of stroke with resolution of presenting symptoms/signs by 24 hours and no acute infarction/hemorrhage on imaging. We used multivariable logistic regression to evaluate associations between study exposures (demographics, comorbidities, stroke characteristics) and outcomes. Results: Among 1009 patients with a median last known well-to-TPA time of 87 minutes, 276 patients (27%) had a time-defined averted stroke (31% MSU, 21% SC) and 159 patients (16%) had a tissue-defined averted stroke (18% MSU, 11% SC). Factors independently associated with time-defined averted stroke were younger age (OR, 0.98; 95% CI, 0.96-0.99), female sex (0R, 0.51; 95% CI, 0.36-0.74), hyperlipidemia (OR, 1.81, 95% CI, 1.24-2.64), normal premorbid function (0R, 2.22; 95% CI, 1.37-3.67), lower glucose (OR, 0.996; 95% CI, 0.993-0.999), lower MAP (OR, 0.991; 95% CI, 0.983-0.998), MSU care (OR, 1.77; 95% CI, 1.21-2.62), lower NIH stroke scale (OR, 0.89; 95% CI, 0.86-0.93), and no large vessel occlusion (LVO) (OR, 0.52; 95% CI, 0.32-0.83). For tissue-based averted stroke, younger age, female sex, hyperlipidemia, lower MAP, MSU treatment, lower NIH stroke scale, and no LVO were significantly associated. Conclusion: In a modern acute stroke trial, one-in-four patients treated with TPA for stroke recovered within 24 hours and one-in-six had no demonstrable brain injury on imaging. Younger age, female sex, hyperlipidemia, lower MAP, MSU care, lower stroke severity, and no LVO may increase the odds of averting stroke.

BackgroundThere is conflicting evidence on the utility of intravenous (IV) alteplase in patients with emergent large vessel occlusion (ELVO) treated with mechanical thrombectomy (MT).MethodsThis was a post hoc analysis of the COMPASS: a trial of aspiration thrombectomy versus stent retriever thrombectomy as first-line approach for large vessel occlusion. We compared clinical, procedural and angiographic outcomes of patients with and without prior IV alteplase administration.ResultsIn the COMPASS trial, 235 patients had presented to the hospital within the first 4 hours of stroke symptom onset and were eligible for analysis. On univariate analysis, administration of IV alteplase prior to MT was found to be significantly associated with favorable outcomes (modified Rankin scale (mRS) 0–2 at 3 months; 55.6% vs 40.0% in the MT-only group, P=0.037). However, on multivariate analysis, only baseline (pre-stroke) mRS, admission National Institutes of Health Stroke Scale (NIHSS) score and age were identified as independent predictors of favorable outcomes at 3 months. We found higher final thrombolysis in cerebral infarction (TICI) 2b/3 rates in patients without the use of alteplase prior to the aspiration first approach (100.0% vs 87.9% in IV altepase +aspiration first MT, P=0.03). In the stent retriever first group, final TICI 2b/3 rates were identical in patients with and without IV alteplase administration (87.5% and 87.5%, P=1.0).ConclusionsPrior administration of IV alteplase may adversely affect the efficacy of aspiration, but does not seem to influence the stent retriever first approach to MT in patients with anterior circulation ELVO.

Background Mobile stroke units (MSUs) are ambulances with staff and a computed tomographic scanner that may enable faster treatment with tissue plasminogen activator (t-PA) than standard m...

Background The clinical efficacy of mechanical thrombectomy has been unequivocally demonstrated in multiple randomized clinical trials. However, these studies were performed in carefully selected centers and utilized strict inclusion criteria. Aim We aimed to assess the clinical effectiveness of mechanical thrombectomy in a prospective registry. Methods A total of 2008 patients from 76 sites across 12 countries were enrolled in a prospective open-label mechanical thrombectomy registry. Patients were categorized into the corresponding cohorts of the SWIFT-Prime, DAWN, and DEFUSE 3 trials according to the basic demographic and clinical criteria without considering specific parenchymal imaging findings. Baseline and outcome variables were compared across the corresponding groups. Results As compared to the treated patients in the actual trials, registry-derived patients tended to be younger and had lower baseline ASPECTS. In addition, time to treatment was earlier and the use of intravenous tissue plasminogen activator (IV-tPA) and general anesthesia were higher in DAWN- and DEFUSE-3 registry derived patients versus their corresponding trials. Reperfusion rates were higher in the registry patients. The rates of 90-day good outcome (mRS0-2) in registry-derived patients were comparable to those of the patients treated in the corresponding randomized clinical trials (SWIFT-Prime, 64.5% vs. 60.2%; DAWN, 50.4% vs. 48.6%; Beyond-DAWN: 52.4% vs. 48.6%; DEFUSE 3, 52% vs. 44.6%, respectively; all P > 0.05). Registry-derived patients had significant less disability than the corresponding randomized clinical trial controls (ordinal modified Rankin Scale (mRS) shift odds ratio (OR), P Conclusion Our study provides favorable generalizability data for the safety and efficacy of thrombectomy in the “real-world” setting and supports that patients may be safely treated outside the constraints of randomized clinical trials.

BackgroundIn large vessel occlusionstroke, navigation of aspiration catheters (AC) can be impeded by vessel tortuosity and the ophthalmic artery origin. A novel tapered delivery catheter was designed to facilitate delivery without disturbing the embolus. We assessed AC deliverability in vitro and validated the observations in a first-in-human experience.MethodsIn a vascular model with three challenging craniocervical scenarios, two commercial AC were advanced from the carotid to the middle cerebral artery by four neurointerventionalists. Catheter deliverability with standard microwire and microcatheter (MC) combinations and the Tenzing 7 (T7) Delivery Catheter (Route 92 Medical, San Mateo, CA) were compared. Operators rated aspects of catheter deliverability on a 5-point scale. Results were compared with device delivery patterns at a neurovascular center before and after clinical introduction of T7.ResultsIn vitro, success rate and speed were higher with T7 (96%; mean 30±10 s) than with MC (65%; 72±47 s, pConclusionCompared with microcatheter and microwire combinations, T7 improves aspiration catheter delivery in vitro, minimizing the need to cross the occlusion. Initial clinical experience appears to validate the model’s observations.

BackgroundClot density (Hounsfield units, HU) and perviousness (post-contrast increase in the HU of clot) are thought to be associated with clot composition. We evaluate whether these imaging characteristics were associated with angiographic outcomes of aspiration and stent retriever thrombectomy in COMPASS: a trial of aspiration thrombectomy versus stent retriever thrombectomy as first-line approach for large vessel occlusion.MethodsClot density and perviousness were measured by two independent operators who were blind to all the final angiographic and clinical outcomes. The association of clot density and perviousness with the Thrombolysis In Cerebral Infarction (TICI) scale after first pass was assessed using univariate and multivariate analysis.ResultsAmong all patients enrolled in COMPASS, 165 were eligible for the post-hoc analysis (81 patients in the aspiration first and 84 in the stent retriever first groups). Overall mean perviousness of clot was significantly higher in patient with mTICI 2b-3 after first pass (28.6±22.9 vs 20.3±19.2, p=0.017). Mean perviousness among patients who achieved TICI 2c/3 versus TICI 2b versus TICI 0-2a in the aspiration first group varied significantly (32.6±26.1, 35.3±24.4, and 17.7±13.1, p=0.013). The association of perviousness with first pass success was not significant in the stent retriever group. Using multivariate analysis, high perviousness (defined as cut-off >27.6) was an independent predictor of TICI 2b-3 (OR 3.82, 95% CI 1.10 to 13.19; p=0.034).ConclusionsClot perviousness is associated with first pass angiographic success in patients treated with the aspiration first approach for thrombectomy.

Background Two recent trials demonstrated a benefit for endovascular therapy (EVT) in the treatment of basilar artery occlusion (BAO). In light of the expected increase in the use of EVT for BAO, we sought to understand the technique preferences of neurointerventionalists performing EVT for BAO. Methods We conducted an international online survey of physician opinions on the use of EVT in BAO between January and March 2022. The survey was distributed through stroke and neurointerventional organizations. Survey questions examined selection of patients for the procedure and the techniques currently used for EVT in BAO. Responses from neurointerventionalists were analyzed. Results More than 3000 participants were invited yielding 1245 respondents, of whom 543 were classified as neurointerventionalists across 52 countries and included in this analysis. Most neurointerventionalists would proceed to EVT for occlusions of the V4 segment, the basilar artery, or the posterior cerebral artery, without regard for prior intravenous thrombolysis. For BAO of embolic etiology, aspiration only thrombectomy was the preferred method of 50.3% of neurointerventionalists. For BAO of intracranial atherosclerotic disease etiology, combined stent retriever and aspiration thrombectomy was the preferred method of 40.5% of neurointerventionalists. The majority of neurointerventionalists (88.0%) would proceed to stenting after 3 or fewer failed passes for patients with BAO of intracranial atherosclerotic disease etiology. In patients undergoing stenting, aspirin and clopidogrel was the most common antiplatelet regime (52.4%). Conclusions Among the surveyed neurointerventionalists, the most common techniques for EVT of patients with BAO were contact aspiration or combined stent retriever with aspiration thrombectomy. For patients with BAO due to intracranial atherosclerotic disease, the majority of neurointerventionalists were willing to stent and do so most often after 3 or fewer failed passes and with the use of dual antiplatelet medications. Further study is needed to determine the optimal technique for EVT of BAO with or without intracranial atherosclerotic disease. Key Words

This meeting abstract was removed due to the OA licensing requirements of this journal. The full abstract is listed here : https://www.svin.org/files/SVIN_2021_Abstracts_for_Web.pdf

Background and Purpose— It remains unclear how experience influences outcomes after the advent of stent retriever technology. We studied the relationship between site experience and outcomes in the Trevo Acute Ischemic Stroke multicenter registry. Methods— The 24 sites that enrolled patients in the Trevo Acute Ischemic Stroke registry were trichotomized into low-volume (4 cases/month). Baseline features, imaging, and clinical outcomes were compared across the 3 volume strata. A multivariable analysis was performed to assess whether outcomes were influenced by site volumes. Results— A total of 624 patients were included and distributed as low- (n=188 patients, 30.1%), medium- (n=175, 28.1%), and high-volume (n=261, 41.8%) centers. There were no significant differences in terms of age (mean, 66±16 versus 67±14 versus 65±15; P =0.2), baseline National Institutes of Health Stroke Scale (mean, 17.6±6.5 versus 16.8±6.5 versus 17.6±6.9; P =0.43), or occlusion site across the 3 groups. Median (interquartile range) times from stroke onset to groin puncture were 266 (181.8–442.5), 239 (175–389), and 336.5 (221.3–466.5) minutes in low-, medium-, and high-volume centers, respectively ( P =0.004). Higher efficiency and better outcomes were seen in higher volume sites as demonstrated by shorter procedural times (median, 97 versus 67 versus 69 minutes; P P ≤0.0001), and higher rates of good outcome (90-day modified Rankin Scale [mRS], ≤2; 39% versus 50% versus 53.4%; P =0.02). There were no appreciable differences in symptomatic intracranial hemorrhage or 90-day mortality. After adjustments in the multivariable analysis, there were significantly higher chances of achieving a good outcome in high- versus low-volume (odds ratio, 1.67; 95% CI, 1.03–2.7; P =0.04) and medium- versus low-volume (odds ratio, 1.75; 95% CI, 1.1–2.9; P =0.03) centers, but there were no significant differences between high- and medium-volume centers ( P =0.86). Conclusions— Stroke center volumes significantly influence efficiency and outcomes in mechanical thrombectomy.

BackgroundThrombectomy is an efficacious treatment for acute ischemic stroke (AIS). However, relatively few studies to date have specifically examined the impact and clinical implications of age on outcomes for thrombectomy in anterior AIS.ObjectiveTo provide a snapshot of patient metrics and outcomes with respect to age following thrombectomy for anterior AIS to supplement the current body of data for predictors of clinical outcomes in a real-world setting.MethodsData were collected for 20 consecutive patients with AIS treated with thrombectomy at 15 high-volume stroke centers across North America between 2015 and 2016. Patients with anterior occlusions were dichotomized based on whether they were older or younger than 80 years. Ordinal logistic regression analyzed how clinical variables impacted disability using 90-day modified Rankin Scale (mRS) scores.ResultsAdequate revascularization (TICI ≥2B) was achieved in 92.3% of patients aged ConclusionThis analysis affirms age is a significant determinant of 90-day mRS scores following thrombectomy for large vessel anterior AIS. Further investigation into risks faced by elderly patients during thrombectomy may provide actionable information to help refine patient selection and improve outcomes.

Background and Purpose— Mechanical thrombectomy (MT) devices have led to improved reperfusion and clinical outcomes in acute ischemic stroke patients with emergent large vessel occlusions; however, less than one-third of patients achieve complete reperfusion. Use of intraarterial thrombolysis in the context of MT may provide an opportunity to enhance these results. Here, we evaluate the use of intraarterial rtPA (recombinant tissue-type plasminogen activator) as rescue therapy (RT) after failed MT in the North American Solitaire Stent-Retriever Acute Stroke registry. Methods— The North American Solitaire Stent-Retriever Acute Stroke registry recruited sites within North America to submit data on acute ischemic stroke patients treated with the Solitaire device. After restricting the population of 354 patients to use of RT and anterior emergent large vessel occlusions, we compared patients who were treated with and without intraarterial rtPA after failed MT. Results— A total of 37 and 44 patients was in the intraarterial rtPA RT and the no intraarterial rtPA RT groups, respectively. Revascularization success (modified Thrombolysis in Cerebral Infarction ≥2b) was achieved in more intraarterial rtPA RT patients (61.2% versus 46.6%; P =0.13) with faster times to recanalization (100±85 versus 164±235 minutes; P =0.36) but was not statistically significant. The rate of symptomatic intracranial hemorrhage (13.9% versus 6.8%; P =0.29) and mortality (42.9% versus 44.7%; P =0.87) were similar between the groups. Good functional outcome (modified Rankin Scale score of ≤2) was numerically higher in intraarterial rtPA patients (22.9% versus 18.4%; P =0.64). Further restriction of the RT population to M1 occlusions only and time of onset to groin puncture ≤8 hours, resulted in significantly higher successful revascularization rates in the intraarterial rtPA RT cohort (77.8% versus 38.9%; P =0.02). Conclusions— Intraarterial rtPA as RT demonstrated a similar safety and clinical outcome profile, with higher reperfusion rates achieved in patients with M1 occlusions. Prospective studies are needed to delineate the role of intraarterial thrombolysis in MT.

Background and Purpose— Mechanical thrombectomy has been shown to improve clinical outcomes in patients with acute ischemic stroke. However, the impact of balloon guide catheter (BGC) use is not well established. Methods— STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever as first-line therapy. In this study, an independent core laboratory, blinded to the clinical outcomes, reviewed all procedures and angiographic data to classify procedural technique, target clot location, recanalization after each pass, and determine the number of stent retriever passes. The primary clinical end point was functional independence (modified Rankin Scale, 0–2) at 3 months as determined on-site, and the angiographic end point was first-pass effect (FPE) success rate from a single device attempt (modified Thrombolysis in Cerebral Infarction, ≥2c) as determined by a core laboratory. Achieving modified FPE (modified Thrombolysis in Cerebral Infarction, ≥2b) was also assessed. Comparisons of clinical outcomes were made between groups and adjusted for baseline and procedural characteristics. All participating centers received institutional review board approval from their respective institutions. Results— Adjunctive technique groups included BGC (n=445), distal access catheter (n=238), and conventional guide catheter (n=62). The BGC group had a higher rate of FPE following first pass (212/443 [48%]) versus conventional guide catheter (16/62 [26%]; P =0.001) and distal access catheter (83/235 [35%]; P =0.002). Similarly, the BGC group had a higher rate of modified FPE (294/443 [66%]) versus conventional guide catheter (26/62 [42%]; P P =0.003). The BGC group achieved the highest rate of functional independence (253/415 [61%]) versus conventional guide catheter (23/55 [42%]; P =0.007) and distal access catheter (113/218 [52%]; P =0.027). Final revascularization and mortality rates did not differ across the groups. Conclusions— BGC use was an independent predictor of FPE, modified FPE, and functional independence, suggesting that its routine use may improve the rates of early revascularization success and good clinical outcomes. Clinical Trial Registration— URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Summary Background Stent retriever thrombectomy of large-vessel occlusion results in better outcomes than medical therapy alone. Alternative thrombectomy strategies, particularly a direct aspiration as first pass technique, while promising, have not been rigorously assessed for clinical efficacy in randomised trials. We designed COMPASS to assess whether patients treated with aspiration as first pass have non-inferior functional outcomes to those treated with a stent retriever as first line. Methods We did a multicentre, randomised, open label, blinded outcome, core lab adjudicated non-inferiority trial at 15 sites (ten hospitals and four specialty clinics in the USA and one hospital in Canada). Eligible participants were patients presenting with acute ischaemic stroke from anterior circulation large-vessel occlusion within 6 h of onset and an Alberta Stroke Program Early CT Score of greater than 6. We randomly assigned participants (1:1) via a central web-based system without stratification to either direct aspiration first pass or stent retriever first line thrombectomy. Those assessing primary outcomes via clinical examinations were masked to group assignment as they were not involved in the procedures. Physicians were allowed to use adjunctive technology as was consistent with their standard of care. The null hypothesis for this study was that patients treated with aspiration as first pass achieve inferior outcomes compared with those treated with a stent retriever first line approach. The primary outcome was non-inferiority of clinical functional outcome at 90 days as measured by the percentage of patients achieving a modified Rankin Scale score of 0–2, analysed by intent to treat; non-inferiority was established with a margin of 0·15. All randomly assigned patients were included in the safety analyses. This trial is registered at ClinicalTrials.gov, number: NCT02466893. Findings Between June 1, 2015, and July 5, 2017, we assigned 270 patients to treatment: 134 to aspiration first pass and 136 to stent retriever first line. A modified Rankin score of 0–2 at 90 days was achieved by 69 patients (52%; 95% CI 43·8–60·3) in the aspiration group and 67 patients (50%; 41·6–57·4) in the stent retriever group, showing that aspiration as first pass was non-inferior to stent retriever first line (p non-inferiority =0·0014). Intracranial haemorrhage occurred in 48 (36%) of 134 in the aspiration first pass group, and 46 (34%) of 135 in the stent retriever first line group. All-cause mortality at 3 months occurred in 30 patients (22%) in both groups. Interpretation A direct aspiration as first pass thrombectomy conferred non-inferior functional outcome at 90 days compared with stent retriever first line thrombectomy. This study supports the use of direct aspiration as an alternative to stent retriever as first-line therapy for stroke thrombectomy. Funding Penumbra.

Background The effect of time from stroke onset to thrombectomy in the extended time window remains poorly characterized. Aim We aimed to analyze the relationship between time to treatment and clinical outcomes in the early versus extended time windows. Methods Proximal anterior circulation occlusion patients from a multicentric prospective registry were categorized into early (≤6 h) or extended (>6–24 h) treatment window. Patients with baseline National Institutes of Health Stroke Scale (NIHSS) ≥ 10 and intracranial internal carotid artery or middle cerebral artery-M1-segment occlusion and pre-morbid modified Rankin scale (mRS) 0–1 (“DAWN-like” cohort) served as the population for the primary analysis. The relationship between time to treatment and 90-day mRS, analyzed in ordinal (mRS shift) and dichotomized (good outcome, mRS 0–2) fashion, was compared within and across the extended and early windows. Results A total of 1603 out of 2008 patients qualified. Despite longer time to treatment (9[7–13.9] vs. 3.4[2.5–4.3] h, p Conclusions The impact of time to thrombectomy on outcomes appears to be time dependent with a steep influence in the early followed by a less significant plateau in the extended window. However, every effort should be made to shorten treatment times regardless of ischemia duration.

Background and Purpose: The clinical efficacy of mechanical thrombectomy (MT) has been unequivocally demonstrated in multiple randomized clinical trials (RCTs). However, these studies were performed in carefully selected centers and utilized strict inclusion criteria. We aim to assess the clinical effectiveness of MT by comparing the specific RCT populations with corresponding patient cohorts derived from a prospective registry. Methods: A total of 2008 patients from 76 sites across 12 countries were enrolled in a prospective open-label MT registry. Patients were categorized into the corresponding cohorts of the SWIFT-Prime, DAWN, and DEFUSE 3 trials based on the age, baseline NIHSS, occlusion site, IV tPA use, pre-morbid mRS and time to treatment criteria used in the RCTs without considering specific parenchymal imaging findings. Baseline and outcome variables were compared across the corresponding groups. Results: As compared to the treated patients in the actual trials, registry-derived patients tended to be younger and had lower baseline ASPECTS. In addition, time to treatment was earlier and the use of IV tPA and general anesthesia were higher in DAWN- and DEFUSE 3-registry derived patients versus their corresponding trials. Reperfusion rates were higher in the registry patients. The rates of 90-day good outcome (mRS 0-2) in registry-derived patients were comparable to those of the patients treated in the corresponding RCTs (SWIFT-Prime, 64.5% vs 60.2%; DAWN, 50.4% vs 48.6%; Beyond-DAWN: 52.4% vs 48.6%; DEFUSE 3, 52% vs 44.6%, respectively; all P>0.05). Registry-derived patients had significant less disability than the corresponding RCT controls (ordinal mRS shift OR, P Conclusion: Our study provides favorable generalizability data for the safety and efficacy of thrombectomy in the “real-world” setting and supports that patients may be safely treated outside the constraints of RCTs and strict guidelines.

Background and ObjectivesTo determine the impact of endovascular therapy for large vessel occlusion stroke in patients with vs those without premorbid disability.MethodsWe performed a post hoc analysis of the TREVO Stent-Retriever Acute Stroke (TRACK) Registry, which collected data on 634 consecutive patients with stroke treated with the Trevo device as first-line endovascular thrombectomy (EVT) at 23 centers in the United States. We included patients with internal carotid or middle cerebral (M1/M2 segment) artery occlusions, and the study exposure was patient- or caregiver-reported premorbid modified Rank Scale (mRS) score ≥2 (premorbid disability [PD]) vs premorbid mRS score of 0 to 1 (no PD [NPD]). The primary outcome was no accumulated disability, defined as no increase in 90-day mRS score from the patient's premorbid mRS score.ResultsOf the 634 patients in TRACK, 407 patients were included in our cohort, of whom 53 (13.0%) had PD. The primary outcome of no accumulated disability was achieved in 37.7% (20 of 53) of patients with PD and 16.7% (59 of 354) of patients with NPD (p < 0.001), while death occurred in 39.6% (21 of 53) and 14.1% (50 of 354) (p < 0.001), respectively. The adjusted odds ratio of no accumulated disability for patients with PD was 5.2 (95% confidence interval [CI] 2.4–11.4, p < 0.001) compared to patients with NPD. However, the adjusted odds ratio for death in patients with PD was 2.90 (95% CI 1.38–6.09, p = 0.005).DiscussionIn this study of patients with anterior circulation acute ischemic stroke treated with EVT, we found that PD was associated with a higher probability of not accumulating further disability compared to patients with NPD but also with higher probability of death.Classification of EvidenceThis study provides Class II evidence that in anterior circulation acute ischemic stroke treated with EVT, patients with PD compared to those without disability were more likely not to accumulate more disability but were more likely to die.

Background and Purpose: Advanced imaging has been increasingly used for patient selection in endovascular stroke therapy. The impact of imaging selection modality on endovascular stroke therapy clinical outcomes in extended time window remains to be defined. We aimed to study this relationship and compare it to that noted in early-treated patients. Methods: Patients from a prospective multicentric registry (n=2008) with occlusions involving the intracranial internal carotid or the M1- or M2-segments of the middle cerebral arteries, premorbid modified Rankin Scale score 0 to 2 and time to treatment 0 to 24 hours were categorized according to treatment times within the early (0–6 hour) or extended (6–24 hour) window as well as imaging modality with noncontrast computed tomography (NCCT)±CT angiography (CTA) or NCCT±CTA and CT perfusion (CTP). The association between imaging modality and 90-day modified Rankin Scale, analyzed in ordinal (modified Rankin Scale shift) and dichotomized (functional independence, modified Rankin Scale score 0–2) manner, was evaluated and compared within and across the extended and early windows. Results: In the early window, 332 patients were selected with NCCT±CTA alone while 373 also underwent CTP. After adjusting for identifiable confounders, there were no significant differences in terms of 90-day functional disability (ordinal shift: adjusted odd ratio [aOR], 0.936 [95% CI, 0.709–1.238], P =0.644) or independence (aOR, 1.178 [95% CI, 0.833–1.666], P =0.355) across the CTP and NCCT±CTA groups. In the extended window, 67 patients were selected with NCCT±CTA alone while 180 also underwent CTP. No significant differences in 90-day functional disability (aOR, 0.983 [95% CI, 0.81–1.662], P =0.949) or independence (aOR, 0.640 [95% CI, 0.318–1.289], P =0.212) were seen across the CTP and NCCT±CTA groups. There was no interaction between the treatment time window (0–6 versus 6–24 hours) and CT selection modality (CTP versus NCCT±CTA) in terms of functional disability at 90 days ( P =0.45). Conclusions: CTP acquisition was not associated with better outcomes in patients treated in the early or extended time windows. While confirmatory data is needed, our data suggests that extended window endovascular stroke therapy may remain beneficial even in the absence of advanced imaging.

BackgroundFirst pass effect (FPE), defined as near-total/total reperfusion of the territory (modified Thrombolysis in Cerebral Infarction (mTICI) 2c/3) of the occluded artery after a single thrombectomy attempt (single pass), has been associated with superior safety and efficacy outcomes than in patients not experiencing FPE.ObjectiveTo characterize the clinical features, incidence, and predictors of FPE in the anterior and posterior circulation among patients enrolled in the Trevo Registry.MethodsData were analyzed from the Trevo Retriever Registry. Univariate and multivariable analyses were used to assess the relationship of patient (demographics, clinical, occlusion location, collateral grade, Alberta Stroke Program Early CT Score (ASPECTS)) and device/technique characteristics with FPE (mTICI 2c/3 after single pass).ResultsFPE was achieved in 27.8% (378/1358) of patients undergoing anterior large vessel occlusion (LVO) thrombectomy. Multivariable regression analysis identified American Society of Interventional and Therapeutic Neuroradiology (ASITN) levels 2–4, higher ASPECTS, and presence of atrial fibrillation as independent predictors of FPE in anterior LVO thrombectomy. Rates of modified Rankin Scale (mRS) score 0–2 at 90 days were higher (63.9% vs 53.5%, pConclusionTwenty-eight percent of patients undergoing anterior LVO thrombectomy and 24% of patients undergoing basilar artery occlusion thrombectomy experience FPE. Independent predictors of FPE in anterior circulation LVO thrombectomy include higher ASITN levels, higher ASPECTS, and the presence of atrial fibrillation.

BackgroundThere is a paucity of data regarding mechanical thrombectomy (MT) in distal arterial occlusions (DAO). We aim to evaluate the safety and efficacy of MT in patients with DAO and compare their outcomes with proximal arterial occlusion (PAO) strokes.MethodsThe Trevo Registry was a prospective open-label MT registry including 2008 patients from 76 sites across 12 countries. Patients were categorized into: PAO: intracranial ICA, and MCA–M1; and DAO: MCA–M2, MCA–M3, ACA, and PCA. Baseline and outcome variables were compared across the PAO vs DAO patients with pre-morbid mRS 0–2.ResultsAmong 407 DAOs including 350 (86.0%) M2, 25 (6.1%) M3, 10 (2.5%) ACA, and 22 (5.4%) PCA occlusions, there were 376 DAO with pre-morbid mRS 0–2 which were compared with 1268 PAO patients. The median baseline NIHSS score was lower in DAO (13 [8–18] vs 16 [12–20], PConclusionEndovascular therapy in DAO appears to result in a comparable safety and technical success profile as in PAO. The potential benefits of DAO thrombectomy should be investigated in future randomized trials.

Background Imaging clot characteristics such as clot density and perviousness (the latter is defined as a difference in regional clot density values between computed tomography angiography (CTA) and non-contrast CT [NCCT]), can be used as an imaging marker characterizing red blood cell and fibrin composition of the clot serving. We aimed to examine whether clot density and perviousness were associated with angiographic outcomes of aspiration and stent retriever thrombectomy in the COMPASS Trial: a Direct Aspiration First Pass Technique trial. Methods Clot density (Hounsfield units, HU) and perviousness were measured by two operators who were blind to all the final angiographic and clinical outcomes except for the knowledge of stroke laterality. NCCT and CTA images were co-registered to accurately localize clot on both imaging modalities. The values were then matched with angiographic and clinical outcome data of the first pass for each randomization arm. Univariate and multivariate analysis was carried out to assess the association of clot density and perviousness using SPSS version 25. Results Of the original 270 patients included in the COMPASS trial, 165 were eligible for the post-hoc analysis (81 patients in the aspiration first and 84 in the stent retriever first groups). There was no difference between the groups in regards to gender distribution, age, laterality and side of large vessel occlusion, smoking status of patients, and comorbidities. There was also no difference between the aspiration and stent retriever first randomization groups in regards to baseline clot Hounsfield units (HU) on NCCT (49.9 ±8.2 vs. 47.8 ±8.7, P=0.11), and perviousness (26.84 ±21.8 vs. 22.8 ±19.9, P=0.20). For the aspiration first group, there was a difference in mean perviousness values among patients who achieved TICI 2c-3 vs. TICI 2b vs. TICI 0–2a (33.1 ±26, 35.9 ±25.1, and 19.0 ±14.2, respectively; P=0.016). There was no difference between clot HU density on NCCT among these 3 groups (48.8 ±8.5, 50.1 ±7.2, and 51.0 ±8.4, P=0.56). In the stent retriever first group, there was no difference in perviousness or HU density of clot in patients with TICI 2c/3, TICI 2b or TICI 0–2a after first pass (perviousness 21.6 ±17.0, 22.4 ±18.04 and 22.6 ±22.9, P=0.97; HU on NCCT 48.7 ±9.1, 49.7 ±6.5 and 46.7 ±9.0, P=0.47).In multivariate analysis using a model that included use of intravenous tPA, balloon guide catheter use, onset to groin puncture and age, perviousness of more than 10 was the only independent factor predictive of successful recanalization (defined as TICI 2b-3) after first pass in the aspiration first group with odds ratio of 3.4 (95% CI 1.0 -12.0). We did not find any significant predictors of successful reperfusion (TICI 2b-3) after first pass in the stent retriever first group. Conclusions Clot perviousness values are associated with first pass angiographic success in patients treated with the aspiration first approach for thrombectomy. Additional research is needed to determine if clot perviousness may be used to identify patients who are more likely to have successful recanalization with aspiration when deciding between aspiration versus stent retriever first approaches. Disclosures M. Mokin: 1; C; NIH R21NS109575. 2; C; Medtronic, Canon medical, Cerenovus. 4; C; Serenity medical, Synchron, VICIS, Endostream. M. Waqas: None. J. Fifi: 1; C; Stryker, Penumbra, Microvention. 4; C; Cerebrotech, The Stroke Project. R. De Leacy: 1; C; Penumbra. 6; C; Cerenovus, Siemens. D. Fiorella: 1; C; Penumbra, Cerenovus, Stryker. 6; C; Genentech, Shape Memory Medical. E. Gu: None. E. Levy: 6; C; Penumbra, NextGen Biologics, Rapid Medical, Cognition Medical, Three Rivers Medical, Stryker, MedX, Endostream Medical. K. Snyder: 6; C; Penumbra, Canon Medical Systems, Medtronic, Jacobs Institute; and other from Neurovascular Diagnostics. R. Hanel: 6; C; Penumbra, Endostream, Cerebrotech, Synchron, InNeuroCo, Medtronic, Microvention, Stryker, Cerenovus; Elum, Three Rivers. A. Aghaebrahim: None. K. Woodward: 6; C; Penumbra. H. Hixson: 6; C; Penumbra. M. Chaudry: 6; C; Penumbra, Pulsar Vascular, Medtronic, Microvention, Codman, Blockade. A. Spiotta: 6; C; Penumbra, Pulsar Vascular, Stryker, Microvention. A. Rai: 6; C; Penumbra, Microvention, Stryker. D. Frei: 6; C; Penumbra, Cerenovus, Stryker, Genentech, Shape Memory Medical, Siemens. J. Delgado Almandoz: 6; C; Penumbra, Medtronic. M. Kelly: 6; C; Penumbra, Medtronic, Endostream. A. Arthur: 6; C; Penumbra. B. Baxter: 6; C; Penumbra, Medtronic, Stryker, Viz, and 880 Medical. J. English: 6; C; Penumbra, Medtronic, Stryker, Route 92 Medical. I. Linfante: 6; C; Penumbra, Medtronic, Stryker, Microvention, InNeuroCo, andThree Rivers. K. Fargen: 6; C; Penumbra and Cerebrotech. A. Turk III: 6; C; Penumbra, Pulsar Vascular, Codman, Microvention, Medtronic, Blockade. A. Siddiqui: 6; C; Amnis Therapeutics, Serenity Medical, Silk Road Medical, Rebound Therapeutics, Penumbra Medtronic, Three Rivers Medical, Microvention, Imperative Care, Cerenovus, Endostream Medical, StimMed, Claret M. J. Mocco: 6; C; Penumbra, Cerebrotech, Rebound Therapeutics, TSP, Lazarus Effect, Medina, Pulsar Vascular, Blockade.

BackgroundIntraoperative neuromonitoring (IONM) is often used during cerebral endovascular procedures.ObjectiveTo investigate the relationship between intraoperative vascular complications and IONM signal changes, and the impact of interventions on signal resolution and postoperative outcomes.MethodsA series of 2278 cerebral endovascular procedures conducted under general anesthesia and using electroencephalography and somatosensory evoked potential monitoring were retrospectively reviewed. A subset of 763 procedures also included motor evoked potentials (MEPs). IONM alerts were categorized as either a partial attenuation or complete loss of signal. Vascular complications were subcategorized as due to rupture, emboli, instrumentation, or vasospasm. Odds ratios (ORs) for new postoperative motor deficits were calculated and diagnostic accuracy was measured using sensitivity, specificity, and likelihood ratios.ResultsThe overall incidence of new postoperative motor deficit was 1.2%; 20.4% in cases with an IONM alert and 0.09% in cases without an alert. Relative to procedures with no alerts, odds of a new deficit increased if there was partial signal attenuation (OR=210.9, 95% CI 44.3 to 1003.5, pConclusionsAn IONM alert associated with an arterial complication is associated with a dramatic increase in odds of a new postoperative deficit; however, if there is resolution of the alert prior to closure, odds of a new deficit decrease significantly.

Background: In large vessel occlusion stroke, intracranial navigation of large-bore aspiration catheters can be impeded by vessel curvature and ophthalmic artery origin. Novel conically-shaped delivery assist devices are designed to facilitate delivery. We assessed aspiration catheter deliverability in several patient-specific in vitro models. Methods: In a flow model replicating vascular access from the femoral to the middle cerebral artery, two different commercially available aspiration catheters were repeatedly advanced through a commercial 0.088” sheath from the carotid bifurcation to the middle cerebral artery by five neurointerventionalists under fluoroscopy. Three craniocervical access scenarios were manufactured based on challenging patient anatomy. Catheter deliverability was assessed with standard microwire/microcatheter combinations (MC) and the Tenzing™ 7 catheter (T7). Procedural characteristics were recorded, and operators rated carotid artery deflection, guide catheter pushback and difficulty passing the ophthalmic artery origin on a 5-point scale (1=none, 5=most severe). Results: Among 117 delivery attempts, the target vessel was reached significantly more often with T7 (96%) than with MC (66%, p Conclusion: Compared to microcatheter & microwire combinations, the T7 delivery assist catheter significantly facilitates aspiration catheter delivery to the target vessel in vitro.

International audience; Background and purpose: The purpose of this study was to evaluate the safety and effectiveness of mechanical thrombectomy (MT) in patients with acute ischaemic stroke related to isolated and primary posterior cerebral artery (PCA) occlusions amongst the patients enrolled in the multicentre post‐market Trevo Registry.Method: Amongst the 2008 patients enrolled in the Trevo Registry with acute ischaemic stroke due to large vessel occlusion treated by MT, 22 patients (1.1%) [10 females (45.5%), mean age 66.2 ± 14.3 years (range 28–91)] had a PCA occlusion [17 P1 (77.3%) and five P2 occlusions (22.7%)]. Recanalization after the first Trevo (Stryker, Fremont, CA, USA) pass and at the end of the procedure was rated using the modified Thrombolysis in Cerebral Infarction (mTICI) score. Procedure‐related complications (i.e. groin puncture complication, perforation, symptomatic haemorrhage, embolus in a new territory) were also recorded. The modified Rankin Scale at 90 days was assessed.Results: Median National Institutes of Health Stroke Scale at admission was 14 (interquartile range 8–16). Stroke aetiology was cardio‐embolic in 68.2% of cases. Half of the patients (11/22) received intravenous tissue plasminogen activator. 54.5% of the patients were treated under general anaesthesia. Reperfusion (i.e. mTICI 2b or 3) after first pass was obtained in 65% of cases. Final mTICI 2b–3 reperfusion was obtained in all cases. Only one (4.5%) procedure‐related complication was recorded (puncture site) that resolved after surgery. At 90‐day follow‐up, modified Rankin Scale 0–2 was obtained in 59% of the patients and 9.1% died within the first 3 months after MT.Conclusion: Mechanical thrombectomy for PCA occlusions seems to be safe (

Background and Purpose— In acute ischemic stroke, fast and complete recanalization of the occluded vessel is associated with improved outcomes. We describe a novel measure for newer generation devices: the first pass effect (FPE). FPE is defined as achieving a complete recanalization with a single thrombectomy device pass. Methods— The North American Solitaire Acute Stroke Registry database was used to identify a FPE subgroup. Their baseline features and clinical outcomes were compared with non-FPE patients. Clinical outcome measures included 90-days modified Rankin Scale score, National Institutes of Health Stroke Scale score, mortality, and symptomatic intracranial hemorrhage. Multivariate analyses were performed to determine whether FPE independently resulted in improved outcomes and to identify predictors of FPE. Results— A total of 354 acute ischemic stroke patients underwent thrombectomy in the North American Solitaire Acute Stroke registry. FPE was achieved in 89 out of 354 (25.1%). More middle cerebral artery occlusions (64% versus 52.5%) and fewer internal carotid artery occlusions (10.1% versus 27.7%) were present in the FPE group. Balloon guide catheters were used more frequently with FPE (64.0% versus 34.7%). Median time to revascularization was significantly faster in the FPE group (median 34 versus 60 minutes; P =0.0003). FPE was an independent predictor of good clinical outcome (modified Rankin Scale score ≤2 was seen in 61.3% in FPE versus 35.3% in non-FPE cohort; P =0.013; odds ratio, 1.7; 95% confidence interval, 1.1–2.7). The independent predictors of achieving FPE were use of balloon guide catheters and non-internal carotid artery terminus occlusion. Conclusions— The achievement of complete revascularization from a single Solitaire thrombectomy device pass (FPE) is associated with significantly higher rates of good clinical outcome. The FPE is more frequently associated with the use of balloon guide catheters and less likely to be achieved with internal carotid artery terminus occlusion.

BACKGROUND The effect of endovascular thrombectomy that is performed more than 6 hours after the onset of ischemic stroke is uncertain. Patients with a clinical deficit that is disproportionately severe relative to the infarct volume may benefit from late thrombectomy. METHODS We enrolled patients with occlusion of the intracranial internal carotid artery or proximal middle cerebral artery who had last been known to be well 6 to 24 hours earlier and who had a mismatch between the severity of the clinical deficit and the infarct volume, with mismatch criteria defined according to age (= 80 years). Patients were randomly assigned to thrombectomy plus standard care (the thrombectomy group) or to standard care alone (the control group). The coprimary end points were the mean score for disability on the utility-weighted modified Rankin scale (which ranges from 0 [death] to 10 [no symptoms or disability]) and the rate of functional independence (a score of 0, 1, or 2 on the modified Rankin scale, which ranges from 0 to 6, with higher scores indicating more severe disability) at 90 days. RESULTS A total of 206 patients were enrolled; 107 were assigned to the thrombectomy group and 99 to the control group. At 31 months, enrollment in the trial was stopped because of the results of a prespecified interim analysis. The mean score on the utility-weighted modified Rankin scale at 90 days was 5.5 in the thrombectomy group as compared with 3.4 in the control group (adjusted difference [Bayesian analysis], 2.0 points; 95% credible interval, 1.1 to 3.0; posterior probability of superiority, >0.999), and the rate of functional independence at 90 days was 49% in the thrombectomy group as compared with 13% in the control group (adjusted difference, 33 percentage points; 95% credible interval, 24 to 44; posterior probability of superiority, >0.999). The rate of symptomatic intracranial hemorrhage did not differ significantly between the two groups (6% in the thrombectomy group and 3% in the control group, P = 0.50), nor did 90-day mortality (19% and 18%, respectively; P = 1.00). CONCLUSIONS Among patients with acute stroke who had last been known to be well 6 to 24 hours earlier and who had a mismatch between clinical deficit and infarct, outcomes for disability at 90 days were better with thrombectomy plus standard care than with standard care alone. (Funded by Stryker Neurovascular; DAWN ClinicalTrials.gov number, NCT02142283.)

Background and Purpose— Mechanical thrombectomy with stent retrievers has become standard of care for treatment of acute ischemic stroke patients because of large vessel occlusion. The STRATIS registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) aimed to assess whether similar process timelines, technical, and functional outcomes could be achieved in a large real world cohort as in the randomized trials. Methods— STRATIS was designed to prospectively enroll patients treated in the United States with a Solitaire Revascularization Device and Mindframe Capture Low Profile Revascularization Device within 8 hours from symptom onset. The STRATIS cohort was compared with the interventional cohort of a previously published SEER patient-level meta-analysis. Results— A total of 984 patients treated at 55 sites were analyzed. The mean National Institutes of Health Stroke Scale score was 17.3. Intravenous tissue-type plasminogen activator was administered in 64.0%. The median time from onset to arrival in the enrolling hospital, door to puncture, and puncture to reperfusion were 138, 72, and 36 minutes, respectively. The Core lab–adjudicated modified Thrombolysis in Cerebral Infarction ≥2b was achieved in 87.9% of patients. At 90 days, 56.5% achieved a modified Rankin Scale score of 0 to 2, all-cause mortality was 14.4%, and 1.4% suffered a symptomatic intracranial hemorrhage. The median time from emergency medical services scene arrival to puncture was 152 minutes, and each hour delay in this interval was associated with a 5.5% absolute decline in the likelihood of achieving modified Rankin Scale score 0 to 2. Conclusions— This largest-to-date Solitaire registry documents that the results of the randomized trials can be reproduced in the community. The decrease of clinical benefit over time warrants optimization of the system of care. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT02239640.

BackgroundRecent randomized clinical trials (RCTs) demonstrated the efficacy of mechanical thrombectomy using stent-retrievers in patients with acute ischemic stroke (AIS) with large vessel occlusions; however, it remains unclear if these results translate to a real-world setting. The TREVO Stent-Retriever Acute Stroke (TRACK) multicenter Registry aimed to evaluate the use of the Trevo device in everyday clinical practice.MethodsTwenty-three centers enrolled consecutive AIS patients treated from March 2013 through August 2015 with the Trevo device. The primary outcome was defined as achieving a Thrombolysis in Cerebral Infarction (TICI) score of ≥2b. Secondary outcomes included 90-day modified Rankin Scale (mRS), mortality, and symptomatic intracranial hemorrhage (sICH).ResultsA total of 634patients were included. Mean age was 66.1±14.8 years and mean baseline NIH Stroke Scale (NIHSS) score was 17.4±6.7; 86.7% had an anterior circulation occlusion. Mean time from symptom onset to puncture and time to revascularization were 363.1±264.5 min and 78.8±49.6 min, respectively. 80.3% achieved TICI ≥2b. 90-day mRS ≤2 was achieved in 47.9%, compared with 51.4% when restricting the analysis to the anterior circulation and within 6 hours (similar to recent AHA/ASA guidelines), and 54.3% for those who achieved complete revascularization. The 90-day mortality rate was 19.8%. Independent predictors of clinical outcome included age, baseline NIHSS, use of balloon guide catheter, revascularization, and sICH.ConclusionThe TRACK Registry results demonstrate the generalizability of the recent thrombectomy RCTs in real-world clinical practice. No differences in clinical and angiographic outcomes were shown between patients treated within the AHA/ASA guidelines and those treated outside the recommendations.

Background and Objective: The first pass effect (FPE; achieving complete recanalization with a single thrombectomy device pass) has been shown to be associated with higher rates of good clinical outcomes in patients with acute ischemic stroke. Here, we investigate clinical and radiographic factors associated with FPE in a large U.S. post-marketing registry (TRACK, Trevo Stent-Retriever Acute Stroke). Methods: We analyzed the TRACK database (multicenter registry of 634 patients from 23 centers from March 2013 through August 2015), which 609 patients were included in the final analysis. FPE was defined as a single pass/use of device, TICI 2c/3 recanalization, and no use of rescue therapy. Analysis of individual patient data from TRACK were performed to analyze clinical and radiographic characteristics associated with FPE as well-compared clinical outcomes defined as modified Rankin Scale (mRS) score at 30 and 90 days from hospital discharge to the non-FPE group. Results: The rate of FPE in TRACK was 23% (140/609). There was no association between patient demographics and FPE, including age (p = 0.36), sex (p = 0.50), race (p = 0.50), location of occlusion (p = 0.26), baseline NIHSS (p = 0.62), or past medical history. There was no difference in the use of a balloon-guide catheter or general anesthesia (49 and 57% with FPE vs. 47 and 64%, p = 0.63 and p = 0.14, respectively). Clinical outcomes were significantly associated with FPE; 63 vs. 44% in non-FPE patients achieved mRS 0-2 at 90 days (p = 0.0004). Conclusion: Our study showed that achieving complete recanalization with a single thrombectomy pass using the Trevo device was highly beneficial. The most common clinical factors that are used to determine eligibility for endovascular therapy, such as NIHSS severity, location of occlusion or patient age were not predictive of the ability to achieve FPE.

Background and Purpose- It remains unclear how experience influences outcomes after the advent of stent retriever technology. We studied the relationship between site experience and outcomes in the Trevo Acute Ischemic Stroke multicenter registry. Methods- The 24 sites that enrolled patients in the Trevo Acute Ischemic Stroke registry were trichotomized into low-volume (2 cases/month), medium-volume (2-4 cases/month), and high-volume centers (4 cases/month). Baseline features, imaging, and clinical outcomes were compared across the 3 volume strata. A multivariable analysis was performed to assess whether outcomes were influenced by site volumes. Results- A total of 624 patients were included and distributed as low- (n=188 patients, 30.1%), medium- (n=175, 28.1%), and high-volume (n=261, 41.8%) centers. There were no significant differences in terms of age (mean, 66±16 versus 67±14 versus 65±15; P=0.2), baseline National Institutes of Health Stroke Scale (mean, 17.6±6.5 versus 16.8±6.5 versus 17.6±6.9; P=0.43), or occlusion site across the 3 groups. Median (interquartile range) times from stroke onset to groin puncture were 266 (181.8-442.5), 239 (175-389), and 336.5 (221.3-466.5) minutes in low-, medium-, and high-volume centers, respectively (P=0.004). Higher efficiency and better outcomes were seen in higher volume sites as demonstrated by shorter procedural times (median, 97 versus 67 versus 69 minutes; P0.001), higher balloon guide catheter use (40% versus 36% versus 59%; P≤0.0001), and higher rates of good outcome (90-day modified Rankin Scale [mRS], ≤2; 39% versus 50% versus 53.4%; P=0.02). There were no appreciable differences in symptomatic intracranial hemorrhage or 90-day mortality. After adjustments in the multivariable analysis, there were significantly higher chances of achieving a good outcome in high- versus low-volume (odds ratio, 1.67; 95% CI, 1.03-2.7; P=0.04) and medium- versus low-volume (odds ratio, 1.75; 95% CI, 1.1-2.9; P=0.03) centers, but there were no significant differences between high- and medium-volume centers (P=0.86). Conclusions- Stroke center volumes significantly influence efficiency and outcomes in mechanical thrombectomy.

Background and objective The first pass effect (FPE) has become a novel measure for neurointerventionalists, achieving a complete recanalization with a single thrombectomy device pass, which has been shown to be associated with higher rates of good clinical outcomes. We describe and expand the FPE to one of a large US post-marketing registry (TRACK, Trevo Stent-Retriever Acute Stroke) to elucidate the effect of a single device pass and clinical outcome. Methods TRACK was a core-laboratory adjudicated multicenter registry of 634 patients from 23 centers aimed to evaluate the use of the Trevo device in everyday clinical practice. The TRACK registry was utilized to identify an FPE subgroup (n=140). Baseline features including demographics and clinical data were compared with the non-FPE patients (n=469). Clinical outcome measures included modified Rankin Scale score (mRS) at 30 and 90 days, National Institutes of Health Stroke Scale (NIHSS) score, symptomatic intracranial hemorrhage (sICH), and mortality. FPE was defined as a single pass/use of a device with TICI 2c/3 recanalization, and no use of rescue therapy. Results 609 patients were included in the FPE (140/609, 23%) vs non-FPE (469/609, 77%) subgroup analysis from the TRACK registry. There was no association between patient demographics and FPE group, including age (p=0.36), sex (p=0.50), race (p=0.49), location of occlusion (p=0.26), baseline NIHSS (p=0.61) past medical history including hypertension (p=0.57), atrial fibrillation (p=0.55), diabetes mellitus (p=0.74), hyperlipidemia (p=0.28), coronary artery disease (p=0.27), or history of smoking (p=0.12). The non-FPE group was associated with higher use of intraarterial tPA (FPE: 11% vs non-FPE: 23%). The onset to puncture time in minutes was not significantly different between groups (p=0.31); however, the total procedural time, total fluoroscopic time, and puncture to reperfusion time had significantly shorter mean time in FPE group (p Conclusion The achievement of complete revascularization from a single Trevo Stent-Retriever device pass is associated with higher rates of good clinical outcomes. Additionally, FPE in our subgroup registry analysis was associated with shorter procedural times, lower NIHSS at discharge, and significantly lower rates of EDT. Our analysis was not able to identify any patient demographics that would be associated to achieve first pass effect. Further research is warranted to confirm findings and identify additional factors achieving good clinical outcome after thrombectomy. Disclosures M. Mokin: 2; C; Claret Medical, Nogueira-Stryker Neurovascular (Trevo-2 Trial Principal Investigator; DAWN Trial Principal Investigator, TREVO Registry Steering Committee), Medtronic (SWIFT Trial Steering Committee; SWIFT-Prime Trial Steering Committee ; STAR Trial Angiographic Core Lab), Penumbra (3D Separator Trial Executive Committee), Neuravi (ARISE-2 Steering Committee), Genentech (Physician Advisory Board), Allm Inc (Physician Advisory Board). C. Primiani: None. A. Castonguay: None. R. Nogueira: None. D. Haussen: None. J. English: None. S. Satti: 2; C; Stryker Neurovascular. J. Chen: None. H. Farid: None. C. Borders: None. E. Veznedaroglu: None. M. Binning: None. A. Puri: None. N. Vora: None. R. Budzik: None. G. Dabus: None. I. Linfante: 2; C; Metronic, Stryker, Penumbra, and Cordis. V. Janardhan: None. A. Alshekhlee: None. M. Abraham: None. R. Edgell: None. M. Taqi: None. R. El Khoury: None. A. Majjhoo: None. M. Kabbani: None. M. Froehler: None. I. Finch: None. S. Ansari: None. R. Novakovic: None. T. Nguyen: None. O. Zaidat: 6; C; overall PI for TRACK, Arise II, Co-PI Therapy Trial, Steering committee STRATIS registry.

Background: The time dependent benefit of rt-PA in acute stroke patients is established. However, only limited data exist on LVO outcomes post remote telemedicine administered rt-PA. We report the outcomes of such patients. Methods: A retrospective study of the CPMC stroke database was performed. Primary outcome measures were neurologic outcome at discharge, mortality, and TICI reperfusion scores of mechanical thrombectomy (MT) treated patients. The safety outcome measure was symptomatic hemorrhage rate (SICH; NIHSS > 1 at ≤ 36hr). Results: From 1/2014-2/2018, 233 transferred rt-PA patients were identified. Median age was 73, and median NIHSS 6. Risk factors included hypertension (69%), dyslipidemia (43%), AF (27%), prior stroke/TIA (26%), CAD (26%), DM (24%), smoking (16%), and CHF (13%). The post rt-PA SICH rate was 4% and discharge mRS≤2 rate was 43%. Mortality rate was 11%, 43% required help at discharge, and 40% were discharged home. For the 61 patients who received rt-PA + MT, the SICH rate was 2% and mortality rate 12%. Median discharge NIHSS was 2 and mRS ≤2 rate was 19%. Of the 233 transferred patients, 40 had a pre rt-PA CTA with LVO available for review. For these patients, median time to scan was 76 min. Median time to repeat CTA at CPMC was 180 min. LVO was 80% anterior circulation, clot migration was seen in 5%, and >90% of MT patients had AF. Post rt-PA recanalization rate was 12% (0% posterior circulation). MT after rt-PA was performed in 62% (TICI ≥ 2b 88%). Longer time to treatment trended towards poorer result and longer MT time. Average NIHSS dropped from 12 to 5 and average discharge mRS was 3. Conclusions: These data confirm that remote IV rt-PA followed by MT is safe and effective. Of LVO rt-PA patients 17% experienced full or partial recanalization suggesting repeat imaging is appropriate before initiating MT, possibly with the exception of posterior circulation strokes because of poor response to rt-PA. AF is common and may predict need for MT after rt-PA. A trend was observed towards improved TICI score and shorter recanalization time with a shorter latency between rt-PA and MT. These data support the use of stroke systems of care to ensure rapid triage and treatment of LVO patients.

Background: Combined neuroprotection with endovascular therapy may improve clinical outcomes of only a subset of individuals treated for acute ischemic stroke. The risk/benefit profile of adjunctive treatment may not warrant neuroprotection with successful reperfusion, yet many other individuals have poor outcomes despite revascularization. We hypothesized that optimal candidates for adjunctive neuroprotection may be defined by analyses of subjects with poor clinical outcome despite successful reperfusion in the Trevo Retriever Registry. Methods: The Trevo Retriever Registry dataset was analyzed to define the subset of cases with poor clinical outcome (day 90 mRS 4-6) after successful reperfusion (eTICI 2b50, 2b67, 2c, 3). Multivariate analyses were used to identify predictors of poor outcome using these distinct definitions of successful reperfusion. The influence of covariates, including TLSW, baseline clinical and imaging variables (e.g. ASPECTS, ASITN collateral grade), on defining such optimal neuroprotective candidates was delineated. Results: Successful reperfusion adjudicated by core lab, defined as eTICI ≥ 2b50 included 1,162 subjects, with eTICI ≥ 2b67 in 920, eTICI ≥ 2c in 652 and eTICI 3 in 209. Poor outcome (day 90 mRS 4-6) occurred in 316/1162 (27%) with eTICI ≥ 2b50, 243/920 (26%) with eTICI ≥ 2b67, 172/652 (26%) with eTICI ≥ 2c and 61/209 (29%) with eTICI 3. Across all subsets, multivariate analyses to predict poor outcome after successful reperfusion identified increased age (per year, OR 1.04-1.05, all p= Conclusions: Neuroprotection combined with endovascular therapy may optimally target stroke patients with worse collaterals, diabetes or increased age. Trial design for neuroprotection with revascularization in AIS should leverage these data.

Background: Two recent trials showed a strong benefit of thrombectomy in the extended window. However, these studies were performed in selected centers and utilized strict inclusion criteria. We aim to evaluate the outcomes of thrombectomy in a large prospective cohort treated outside the rigid clinical trial setting. Methods: Trevo Registry patients with ICA, MCA-M1 or M2 occlusions and pre-morbid mRS0-2 were categorized according to time-from-last-seen-well (TLSW) to puncture as early (0-6hours) vs. late (6-24hours). Uni- and multivariate analyzes were performed to identify good outcome (90-day mRS0-2) predictors. Subgroup analyses were performed for the basic DAWN (age >=18, NIHSS >=10, ICA or M1 occlusion, pre-morbid mRS 0-1) and DEFUSE 3 (age 18-90, NIHSS >=6, ICA or MCA-M1 occlusion, mRS 0-2) trial criteria. Results: As compared to the late (n=430), early patients (n=1173) were older (70 vs 68, p=0.011) and had higher IV tPA use (69 vs 25%, p= 6 (1.37 [1.07-1.75]), DM (0.58 [0.44-0.77]), and time to treatment (0.98 [0.97-1.00]) were independent predictors of good outcomes. Imaging modality did not predict outcomes. Similar findings were observed in the early versus late DAWN-like (n=709 vs 257) and DEFUSE 3-like (n=855 vs 273) cohorts. There was great similarity between the outcomes of the Trevo Registry subsets vs their analogous RCTs: early DAWN-like vs SWIFT Prime (90-day mRS 0-2: 57.5 vs 60%; 90-day mRS 6: 11.% vs 9%), Late DAWN-like vs DAWN (50.2 vs 48.6%; 10.6 vs 18%), and Late DEFUSE 3-like vs DEFUSE 3 (52 vs 45%; 10.3 vs 14%). Conclusions: Our study provides favorable data for the generalizability of the safety and efficacy of thrombectomy in the “real-world” setting.

Background: Time to reperfusion (TTR) is commonly cited in clinical outcome after endovascular treatment of acute ischemic stroke, yet collaterals may set the pace of ischemia. Real-world data on fast and slow progressors also remain scarce. We analyzed the impact of TTR on clinical outcome in real-world data using core lab adjudicated angiography, interventional steps and corresponding reperfusion. Methods: 16 key time intervals were calculated from workflow (time of symptom onset, door, picture, puncture) and core lab metrics (clot visualization, first deployment, first reperfusion, final angiography) in real-world data from the Trevo Retriever Registry. These 16 variations of TTR were analyzed overall and by collateral status (ASITN 0-1 versus 2 versus 3-4) to determine the relationship with 90-day clinical outcomes. Results: Real-world data on endovascular therapy from 1,441 subjects in the Trevo Retriever Registry were analyzed to relate TTR with clinical outcomes. Overall metrics for TTR are shown in Table 1. TTR was not linked with collateral status. Using a multivariate model incorporating known predictors, there was no influence of TTR using any of the 16 definitions on clinical outcome. Better collateral status on DSA prior to revascularization showed a potent relationship with 90-day mRS (p Conclusions: Collaterals transform time to reperfusion, linking fast and slow progressors with subsequent clinical outcomes. TTR may be standardized based on these 16 key epochs in endovascular stroke therapy to document workflow metrics. Time is relative, even when measured with detailed, standardized metrics.

Background Recent randomized controlled trials show benefit of thrombectomy for large vessel occlusion in stroke. Real‐world data aid in assessing reproducibility of outcomes outside of clinical trials. The Trevo Retriever Registry is a multicenter, international, prospective study designed to assess outcomes in a large cohort of patients. Methods and Results The Trevo Registry is a prospective database of patients with large vessel occlusion treated with the Trevo device as the first device. The primary end point is revascularization based on modified Thrombolysis in Cerebral Infarction score and secondary end points include 90‐day modified Rankin Scale, 90‐day mortality, neurological deterioration at 24 hours, and device/procedure related adverse events. Year 2008 patients were enrolled at 76 centers in 12 countries. Median admission National Institutes of Health Stroke Scale was 16 (interquartile range, 11–20). Occlusion sites were internal carotid artery (17.8%), middle cerebral artery (73.5%), posterior circulation (7.1%), and distal vascular locations (1.6%). A modified Thrombolysis in Cerebral Infarction 2b or 3 was achieved in 92.8% (95% CI, 91.6, 93.9) of procedures, with 55.3% (95% CI, 53.1, 57.5) of patients achieving modified Rankin Scale ≤2 at 3 months. Patients meeting revised 2015 American Heart Association criteria for thrombectomy had a 59.7% (95% CI , 56.0; 63.4) modified Rankin Scale 0 to 2 at 3 months, whereas 51.4% treated outside of American Heart Association criteria had modified Rankin Scale 0 to 2. 51.4% (95% CI , 49.6, 55.4). Symptomatic intracranial hemorrhage rate was 1.7% (95% CI , 1.2, 2.4). Conclusions The Trevo Retriever Registry represents real‐world data with stent retriever. The registry demonstrates similar reperfusion rates and outcomes in the community compared with rigorous centrally adjudicated clinical trials. Future subgroup analysis of this cohort will assist in identifying areas of future research. Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 02040259.

BACKGROUND AND PURPOSE: Comparing outcomes between endovascular aneurysm coiling trials can be difficult because of heterogeneity in patients and end points. We sought to understand the impact of geography on aneurysm retreatment in patients enrolled in the Matrix and Platinum Science Trial. MATERIALS AND METHODS: Post hoc analysis was performed on data from the Matrix and Platinum Science trial. Patients were stratified as either North American or international. Baseline patient demographics, comorbidities, aneurysm characteristics, procedural complications, and clinical and angiographic outcomes were compared. RESULTS: We evaluated 407 patients from 28 North American sites and 219 patients from 15 international sites. Patient demographics differed significantly between North American and international sites. Aneurysms were well occluded postprocedure more often at international than North American sites ( P < .001). Stents were used significantly more often at North American sites (32.7% [133 of 407]) compared with international sites (10.0% [22 of 219]; P < .001). At 455 days, there was no difference in the proportion of patients alive and free of disability ( P = .56) or with residual aneurysm filling ( P = .10). Ruptured aneurysms were significantly more likely to have been retreated at North American sites within the first year ( P < .001) and at 2 years ( P < .001). Among all patients for whom the treating physician believed there to be Raymond 3 aneurysm filling at follow-up, absolute rates of retreatment at international and North American sites were similar by 2-year follow-up. CONCLUSIONS: Data from the Matrix and Platinum Science Trial demonstrate that aneurysm retreatment occurs with different frequency and at different times in different regions of the world. This trend has critical value when interpreting trials reporting short-term outcomes, especially when judgment-based metrics such as retreatment are primary end points that may or may not take place within the defined study follow-up period. Though these variations can be controlled for and balanced within a given randomized trial, such differences in practice patterns must be accounted for in any attempt to compare outcomes between different trials. Despite these differences, endovascular-treated intracranial aneurysms around the world have similar clinical outcomes.

BackgroundThrombectomy for anterior large vessel occlusion less than 24 hours since last known well is now standard of care. Certain aspects of clinical trials may limit generalizability to ’real-world' practice.ObjectiveTo compare revascularization rates and outcomes for direct aspiration (ADAPT) and stent retriever thrombectomy following anterior acute ischemic stroke (AIS) in a real-life setting.MethodsData from the most recent 20 consecutive patients with AIS treated with mechanical thrombectomy between 2015 and 2016 were collected from 15 high-volume stroke centers across North America for a total of 300 cases. Patients with proximal anterior large vessel occlusions were dichotomized by primary treatment technique. Ordinal logistic regression assessed the effects of clinical variables on patient disability using 90-day modified Rankin Scale (mRS) scores.ResultsAdequate revascularization (Thrombolysis in Cerebral Infarction ≥2b) was ultimately achieved in 91.2% of first-line direct aspiration (ADAPT) cases with an average of 1.9±1.9 passes and in 87.5% of stent retriever cases with an average of 1.7±1.0 passes. Time from groin puncture to revascularization was shorter for ADAPT cases. The mean 90-day mRS score for both groups was 3.0±2.4. Number of passes using primary technique, and postintervention intracranial hemorrhage, were significant predictors of 90-day mRS scores after ADAPT, while age and preprocedure mRS score were predictive of outcomes following first-line stent retriever.ConclusionsOur data show similar adequate revascularization rates and 90-day functional outcomes for first-line direct aspiration and stent retrievers for anterior large vessel occlusion in a real-world setting. These results support the findings of other prospective trials evaluating the two techniques.

IntroductionThe Solitaire stent retriever registry showed improved reperfusion, faster procedure times, and better outcome in acute stroke patients with large vessel occlusion treated with a balloon guide catheter (BGC) and Solitaire stent retriever compared with a conventional guide catheter. The goal of this study was to evaluate whether use of a BGC with the Trevo stent retriever improves outcomes compared with a conventional guide catheter.MethodsThe TRACK registry recruited 23 sites to submit demographic, clinical, and site adjudicated angiographic and outcome data on consecutive patients treated with the Trevo stent retriever. BGC use was at the discretion of the physician.Results536 anterior circulation patients (of whom 279 (52.1%) had BGC placement) were included in this analysis. Baseline characteristics were notable for younger patients in the BGC group (65.4±15.3 vs 68.1±13.6, P=0.03) and lower rate of hypertension (72% vs 79%, P=0.06). Mean time from symptom onset to groin puncture was longer in the BGC group (357 vs 319 min, P=0.06).Thrombolysis in Cerebral Infarction 2b/3 scores were higher in the BGC cohort (84% vs 75.5%, P=0.01). There was no difference in reperfusion time, first pass effect, number of passes, or rescue therapy. Good clinical outcome at 3 months was superior in patients with BGC (57% vs 40%; P=0.0004) with a lower mortality rate (13% vs 23%, P=0.008). Multivariate analysis demonstrated that BGC use was an independent predictor of good clinical outcome (OR 2; 95% CI 1.3 to 3.1, P=0.001).ConclusionsIn acute stroke patients presenting with anterior circulation large vessel occlusion, use of a BGC with the Trevo stent retriever resulted in improved reperfusion, improved clinical outcome, and lower mortality.

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: Various techniques are used to enhance the results of mechanical thrombectomy with stent-retrievers, including proximal arrest with balloon guide catheter (BGC), conventional large bore proximal catheter (CGC), or in combination with local aspiration through a large-bore catheter positioned at the clot interface (Aspiration-Retriever Technique for Stroke [ARTS]). We evaluated the impact of ARTS in the North American Solitaire Acute Stroke (NASA) registry. Summary: Data on the use of the aspiration technique were available for 285 anterior circulation patients, of which 29 underwent ARTS technique, 131 CGC, and 125 BGC. Baseline demographics were comparable, except that ARTS patients are less likely to have hypertension or atrial fibrillation. The ARTS group had more ICA occlusions (41.4 vs. 22% in the BGC, p = 0.04 and 26% in CGC, p = 0.1) and less MCA/M1 occlusions (44.8 vs. 68% in BGC and 62% in CGC). Time from arterial puncture to reperfusion or end of procedure with ARTS was shorter than with CGC (54 vs. 91 min, p = 0.001) and was comparable to the BGC time (54 vs. 67, p = 0.11). Final degree of reperfusion was comparable among the groups (TICI [modified Thrombolysis in Cerebral Infarction] score 2b or higher was 72 vs. 70% for CGC vs. 78% for BGC). Procedural complications, mortality, and good clinical outcome at 90 days were similar between the groups. Key Messages: The ARTS mechanical thrombectomy in acute ischemic stroke patients appears to yield better results as compared to the use of CGCs with no significant difference when compared to BGC. This early ARTS technique NASA registry data are limited by the earlier generation distal large bore catheters and small sample size. Future studies should focus on the comparison of ARTS and BGC techniques.

Background: Time to mechanical thrombectomy is a significant driver of outcomes in acute ischemic stroke (AIS) patients presenting with large vessel occlusion (LVO). We aimed to evaluate predictors of onset to groin puncture (OTG), groin puncture to reperfusion (GTR), and onset to reperfusion (OTR) times in AIS patients treated with the Trevo stent-retriever. Methods: The investigator-initiated TRACK registry recruited 23 clinical sites to submit demographic, clinical, site-adjudicated angiographic, and outcome data on consecutive patients treated with the Trevo device. We included patients treated Results: Among 433 patients analyzed (mean age 66.8 +/- 14.6 years; median NIHSS score 18; 88% anterior circulation), the median times were: OTG 240, GTR 64, and OTR 321 minutes. In multivariable analysis (Table), the independent predictors were: 1) OTG: transfer status and general anesthesia (GA) use; 2) GTR: 1 pass attempt only, use of rescue therapy, GA use, and baseline mRS >1; and 3) OTR: transfer status, use of perfusion imaging, anterior circulation LVO, use of rescue therapy, and 1 pass attempt only. Conclusions: Major pre-treatment contributors to delays to reperfusion in AIS patients treated

Background: The delay and dispersion of collateral circulation to the MCA territory is readily available prior to endovascular thrombectomy for acute ischemic stroke (AIS). Factors associated with collateral grade have never been established in such an extensive population, reflecting diverse subjects from around the world. Largescale data from the Trevo Retriever Registry enables mapping of the MCA collaterome for the first time. Methods: The Imaging and Angiography Core Lab of the Trevo Retriever Registry independently conducted prospective evaluation of angiography in more than 1,500 subjects. Collaterals were systematically scored using ASITN grade prior to thrombectomy. Descriptive statistics detailed the distribution of collateral grades and analyses with demographic, imaging and clinical variables to explore key associations with routinely acquired registry data. Results: 890 subjects (68.5 ± 15.1 years; 54.6% women; baseline NIHSS median 15 (10-19)) with AIS due to MCA occlusion had angiography of collateral circulation centrally adjudicated. Proximal M1 MCA occlusion was noted in 671/890 (75.4%). Collateral grade prior to thrombectomy included grade 4 or most robust collaterals in 38/890 (4.3%), 3 in 294/890 (33.0%), 2 in 467/890 (52.5%), 1 in 80/890 (9%) and 0 or none in 11/890 (1.2%). Baseline collaterals at angiography and pre-procedure ASPECTS were closely correlated (r=0.439, p6s) hypoperfusion at-risk (r=-0.10, n=391; p=0.043) volumes. First pass mTICI≥2b occurred in 553/858 (64.5%) with final mTICI≥2b in 824/890 (92.6%). Collateral grade prior to thrombectomy (each 1-point increment, after adjustment for other predictors) was strongly associated (OR 1.38 95%CI (1.12-1.7), p=0.002) with good clinical outcomes (mRS 0-2) at 90 days. Conclusions: Largescale mapping of collaterals prior to MCA thrombectomy reveals marked variation in the extent and functional impact of the collaterome. The preponderance of partial perfusion in the downstream ischemic territory prompts the need to investigate and leverage the protective nature of the collaterome in AIS.

Introduction: Approximately 2/3 of all AIS present with NIHSS 0-5. While it has been demonstrated that LVO can be found in ~10-20% of all low NIHSS patients, outcome data in this population remains scarce. Indeed, only 14/1766 patients in the recent endovascular RCTs had baseline (b) NIHSS in the 0-5 range. Yet, the presence of LVO in the setting of low NIHSS is associated with ~10-fold increase in subsequent deterioration. We aim to describe the outcomes in a large cohort of low NIHSS patients undergoing thrombectomy. Methods: Patients derived from a large prospective multicenter international stent-retriever registry (Trevo Registry, n=2,010). Baseline and outcome variables were compared according to bNIHSS 0-8 vs >8 and bNIHSS 0-5 vs >5. The primary and secondary efficacy endpoints were the rates of 90-day mRS 0-2 and mTICI 2b-3, respectively. Safety endpoints included sICH and 90-day mortality. Results: A total of 1,985 patients were included. As compared with patients with higher baseline NIHSS, low baseline NIHSS (0-8, n=342; 0-5, n=160) patients were younger, had less comorbidities and better functional status, more frequently had MCA-M2 or vertebrobasilar occlusions, less frequently received IV tpa, and underwent thrombectomy at later times (Table 1). The reperfusion outcomes were nearly the same. There were no significant differences in procedure-related complications, which were overall low (Table 2). The rates of 90-day mRS 0-2 were significantly higher in the lower NIHSS patients (p Conclusion: Despite safe and efficacious endovascular reperfusion, low-NIHSS LVO patients have a relatively high proportion of bad outcomes. This supports the notion that many of "mildly" presenting patients do not fare well. A randomized clinical trial including immediate endovascular treatment in this patient population is warranted.

Background and Aims: Balloon Guide Catheter (BGC) use during thrombectomy treatment in Stroke patients has been reported to have positive effects on revascularization, procedural characteristics, and clinical outcomes. We evaluate the use of BGC in an open-label large prospective TREVO Retriever Registry of real world patients to determine predictors of good ‘clinical’ outcomes. Method: Consecutive Trevo Registry patients that had Balloon Guide Catheter (BGC) used during their thrombectomy procedure were identified; a subset of patients who fulfilled the criteria (ICA and/or MCA-M1/M2 occlusion with pre-morbid mRS 0-1, TLSW ≤6 hrs) within the cohort were also identified. Multivariate analysis was performed to identify the predictors of good outcomes in BGC thrombectomy patients. Results: A total of 1031 BGC treated Trevo Registry patients (overall enrolled, n=2010) qualified for analysis, of which 605 patients fulfilling the subset criteria were identified. The mean age of BGC/stent retriever patients was 67.5 with a median (IQR) baseline NIHSS of 15(11-19). Occlusion location of the BCG group was ICA -20.4%, M1- 57.1%, M2/M3-20.3%, and Posterior 1.8%. In the overall BGC cohort, the median (IQR) time to treatment was (4.2 (3.0,6.5)- hrs.) with conscious/local sedation used in 63.4% and general anesthesia used in 37.3% of cases. The median number of passes with Trevo stent retriever was 1 and revascularization (mTICI ≥ b) was achieved in 92.8% of cases. The sICH rate was low at 1.9% (20/1031) with a low rate of vessel perforation (0.2%). At 90 days post stroke, 56.0% of patients achieved functional independence (mRS 0-2) with 63.7% of the subset of “guidline “ BGC patients achieving functional independence at 90 days. Multivariate logistic regression showed age (aOR 0.97 [0.96, 0.99] P Conclusion: Data from Trevo Registry demonstrate the use of BGC in thrombectomy procedure is safe, and leads to a reduction of disability in ischemic stroke patients.