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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 Mechanical thrombectomy (MT) is the standard of care for the treatment of proximal anterior circulation large vessel occlusions. However, little is known about its efficacy and safety in the treatment of distal intracranial occlusions. Methods This is a multicenter retrospective study of patients treated with MT at 15 comprehensive centers between January 2015 and December 2018. The study cohort was divided into 2 groups based on the location of occlusion (proximal vs. distal). Distal occlusion was defined as occlusion of M3 segment of the middle cerebral artery, any segment of the anterior cerebral artery, or any segment of the posterior cerebral artery. Only isolated distal occlusion was included. Good outcome was defined as 90-day modified Rankin scale score 0–2. Results A total of 4710 patients were included in this study, of whom 189 (4%) had MT for distal occlusions. Compared with the proximal occlusion group, distal occlusion group had a higher rate of good outcome (45% vs. 36%; P = 0.03) and a lower rate of successful reperfusion (78% vs. 84%; P = 0.04). However, the differences did not retain significance in adjusted models. Otherwise there was no difference in the rate of hemorrhagic complications, mortality, or procedure-related complications between the 2 groups. Successful reperfusion, age, and admission stroke severity emerged as predictors of good functional outcome in the distal occlusion group. Conclusions Thrombectomies of distal vessels achieve high rate of successful reperfusion with similar safety profile to those in more proximal locations.

Intra-aortic CT Angiography (IA-CTA) is a relatively new technique that shows promise in efficient diagnosis and evaluation of the angioarchitecture of spinal dural arteriovenous fistulae(sdAVF). The authors document the first reported use of a 4D-CT and C-arm fluoroscope in a hybrid interventional suite to evaluate a sdAVF. Time resolved IA-CTA is clinically feasible in the evaluation of sdAVF, has higher temporal resolution as compared to standard IA-CTA and reduced contrast load, radiation dose and potential for procedural complications as compared to standard spinal angiography.

BackgroundThe benefit of complete reperfusion (modified Thrombolysis in Cerebral Infarction (mTICI) 3) over near-complete reperfusion (≥90%, mTICI 2c) remains unclear. The goal of this study is to compare clinical outcomes between mechanical thrombectomy (MT)-treated stroke patients with mTICI 2c versus 3.MethodsThis is a retrospective study from the Stroke Thrombectomy and Aneurysm Registry (STAR) comprising 33 centers. Adults with anterior circulation arterial vessel occlusion who underwent MT yielding mTICI 2c or mTICI 3 reperfusion were included. Patients were categorized based on reperfusion grade achieved. Primary outcome was modified Rankin Scale (mRS) 0–2 at 90 days. Secondary outcomes were mRS scores at discharge and 90 days, National Institutes of Health Stroke Scale score at discharge, procedure-related complications, and symptomatic intracerebral hemorrhage.ResultsThe unmatched mTICI 2c and mTICI 3 cohorts comprised 519 and 1923 patients, respectively. There was no difference in primary (42.4% vs 45.1%; p=0.264) or secondary outcomes between the unmatched cohorts. Reperfusion status (mTICI 2c vs 3) was also not predictive of the primary outcome in non-imputed and imputed multivariable models. The matched cohorts each comprised 191 patients. Primary (39.8% vs 47.6%; p=0.122) and secondary outcomes were also similar between the matched cohorts, except the 90-day mRS which was lower in the matched mTICI 3 cohort (p=0.049). There were increased odds of the primary outcome with mTICI 3 in patients with baseline mRS ≥2 (36% vs 7.7%; p=0.011; pinteraction=0.014) and a history of stroke (42.3% vs 15.4%; p=0.027; pinteraction=0.041).ConclusionsComplete and near-complete reperfusion after MT appear to confer comparable outcomes in patients with acute stroke.

BackgroundThe Woven EndoBridge (WEB) device is approved in the USA for treatment of unruptured wide-neck bifurcation aneurysms. However, the safety and effectiveness of the WEB device in the treatment of ruptured intracranial aneurysms is not clear. We aim to evaluate the perioperative safety and effectiveness of the WEB device in patients with ruptured intracranial aneurysms.MethodsThis retrospective study, conducted at eight centers in the USA, included patients with ruptured intracranial aneurysms treated with the WEB device in the setting of subarachnoid hemorrhage (SAH). Safety outcomes included intraoperative complications such as vessel perforation, thromboembolic events, and postoperative hemorrhagic or thromboembolic complications based on radiologic imaging. The primary effectiveness outcome was adequate (complete and neck remnant) aneurysm occlusion, according to the Raymond–Roy classification.ResultsA total of 91 patients with 94 ruptured intracranial aneurysms were included (mean age 57.7±15.2 years; 68.1% women; 82.9% wide-necked). Aneurysms were located in the anterior communicating artery (42/94, 44.6%), middle cerebral artery (16/94, 17%), and basilar artery (15/94, 16%). Adequate occlusion was achieved in 48.8% (41/84) and 80.0% (40/50) at discharge and last follow-up (mean of 3.4 months), respectively. At discharge, procedural-related morbidity was 3.3% (3/91) and there was no procedure-related mortality. No re-rupture or delayed aneurysm rupture was observed.ConclusionsThis study demonstrates the perioperative safety and effectiveness of the WEB device for the treatment of patients with ruptured intracranial aneurysms in the setting of SAH, with low periprocedural morbidity and mortality. Long-term follow-up is warranted.

OBJECTIVETraditionally, stent-assisted coiling and balloon remodeling have been the primary endovascular treatments for wide-necked intracranial aneurysms with complex morphologies. PulseRider is an aneurysm neck reconstruction device that provides parent vessel protection for aneurysm coiling. The objective of this study was to report early postmarket results with the PulseRider device.METHODSThis study was a prospective registry of patients treated with PulseRider at 13 American neurointerventional centers following FDA approval of this device. Data collected included clinical presentation, aneurysm characteristics, treatment details, and perioperative events. Follow-up data included degree of aneurysm occlusion and delayed (> 30 days after the procedure) complications.RESULTSA total of 54 aneurysms were treated, with the same number of PulseRider devices, across 13 centers. Fourteen cases were in off-label locations (7 anterior communicating artery, 6 middle cerebral artery, and 1 A1 segment anterior cerebral artery aneurysms). The average dome/neck ratio was 1.2. Technical success was achieved in 52 cases (96.2%). Major complications included the following: 3 procedure-related posterior cerebral artery strokes, a device-related intraoperative aneurysm rupture, and a delayed device thrombosis. Immediately postoperative Raymond-Roy occlusion classification (RROC) class 1 was achieved in 21 cases (40.3%), class 2 in 15 (28.8%), and class 3 in 16 cases (30.7%). Additional devices were used in 3 aneurysms. For those patients with 3- or 6-month angiographic follow-up (28 patients), 18 aneurysms (64.2%) were RROC class 1 and 8 (28.5%) were RROC class 2.CONCLUSIONSPulseRider is being used in both on- and off-label cases following FDA approval. The clinical and radiographic outcomes are comparable in real-world experience to the outcomes observed in earlier studies. Further experience is needed with the device to determine its role in the neurointerventionalist’s armamentarium, especially with regard to its off-label use.

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.

To assess the impact of COVID-19 on neurovascular research and deal with the challenges imposed by the pandemic.MethodsA survey-based study focused on randomized controlled trials (RCTs) and single-arm studies for acute ischemic stroke and cerebral aneurysms was developed by a group of senior neurointerventionalists and sent to sites identified through the clinical trials website (https://clinicaltrials.gov/), study sponsors, and physician investigators.ResultsThe survey was sent to 101 institutions, with 65 responding (64%). Stroke RCTs were being conducted at 40 (62%) sites, aneurysm RCTs at 22 (34%) sites, stroke single-arm studies at 37 (57%) sites, and aneurysm single-arm studies at 43 (66%) sites. Following COVID-19, enrollment was suspended at 51 (78%) sites—completely at 21 (32%) and partially at 30 (46%) sites. Missed trial-related clinics and imaging follow-ups and protocol deviations were reported by 27 (42%), 24 (37%), and 27 (42%) sites, respectively. Negative reimbursements were reported at 17 (26%) sites. The majority of sites, 49 (75%), had put new trials on hold. Of the coordinators, 41 (63%) worked from home and 20 (31%) reported a personal financial impact. Remote consent was possible for some studies at 34 (52%) sites and for all studies at 5 (8%) sites. At sites with suspended trials (n=51), endovascular treatment without enrollment occurred at 31 (61%) sites for stroke and 23 (45%) sites for aneurysms. A total of 277 patients with acute ischemic stroke and 184 with cerebral aneurysms were treated without consideration for trial enrollment.ConclusionWidespread disruption of neuroendovascular trials occurred because of COVID-19. As sites resume clinical research, steps to mitigate similar challenges in the future should be considered.

BackgroundInfection from the SARS-CoV-2 virus has led to the COVID-19 pandemic. Given the large number of patients affected, healthcare personnel and facility resources are stretched to the limit; however, the need for urgent and emergent neurosurgical care continues. This article describes best practices when performing neurosurgical procedures on patients with COVID-19 based on multi-institutional experiences.MethodsWe assembled neurosurgical practitioners from 13 different health systems from across the USA, including those in hot spots, to describe their practices in managing neurosurgical emergencies within the COVID-19 environment.ResultsPatients presenting with neurosurgical emergencies should be considered as persons under investigation (PUI) and thus maximal personal protective equipment (PPE) should be donned during interaction and transfer. Intubations and extubations should be done with only anesthesia staff donning maximal PPE in a negative pressure environment. Operating room (OR) staff should enter the room once the air has been cleared of particulate matter. Certain OR suites should be designated as covid ORs, thus allowing for all neurosurgical cases on covid/PUI patients to be performed in these rooms, which will require a terminal clean post procedure. Each COVID OR suite should be attached to an anteroom which is a negative pressure room with a HEPA filter, thus allowing for donning and doffing of PPE without risking contamination of clean areas.ConclusionBased on a multi-institutional collaborative effort, we describe best practices when providing neurosurgical treatment for patients with COVID-19 in order to optimize clinical care and minimize the exposure of patients and staff.

BackgroundFew studies have examined the trends in clinical and economic outcomes of patients with acute ischemic stroke (AIS) who receive endovascular therapy (ET) in the real-world setting.ObjectiveTo evaluate characteristics and trends in clinical and economic outcomes among commercially insured patients with AIS undergoing ET between 2011 and 2017.MethodsPatients with AIS undergoing ET from January 1, 2011 to June 30, 2017 were identified from administrative claims contained in the IBM MarketScan Commercial and Medicare Supplemental databases. The Mann–Kendall trend test was performed to examine clinical and economic trends.Between 2011 and 2017, 3411 patients (mean age 62.85±15 years) with a primary diagnosis of AIS underwent ET (coverage: Commercial 59%, n=2008; Medicare Supplemental 41%, n=1403). In the Commercial cohort, discharge to home increased significantly (from 29.54% to 39.18%, pConclusionsAlthough with some variation across the samples studied, outcomes including discharge to home, length of stay, readmission, and total cost associated with endovascular stroke therapy seemed to have improved between 2011 and 2017. Index admission cost remained unchanged.

Background and Purpose: Epidemiological studies have shown racial and ethnic minorities to have higher stroke risk and worse outcomes than non-Hispanic Whites. In this cohort study, we analyzed the STAR (Stroke Thrombectomy and Aneurysm Registry) database, a multi-institutional database of patients who underwent mechanical thrombectomy for acute large vessel occlusion stroke to determine the relationship between mechanical thrombectomy outcomes and race. Methods: Patients who underwent mechanical thrombectomy between January 2017 and May 2020 were analyzed. Data included baseline characteristics, vascular risk factors, complications, and long-term outcomes. Functional outcomes were assessed with respect to Hispanic status delineated as non-Hispanic White (NHW), non-Hispanic Black (NHB), or Hispanic patients. Multivariate analysis was performed to identify variables associated with unfavorable outcome or modified Rankin Scale ≥3 at 90 days. Results: Records of 2115 patients from the registry were analyzed. Median age of Hispanic patients undergoing mechanical thrombectomy was 60 years (72–84), compared with 63 years (54–74) for NHB, and 71 years (60–80) for NHW patients ( P P P P Conclusions: Hispanic patients are less likely to have favorable outcome at 90 days following mechanical thrombectomy compared to NHW or NHB patients. Further prospective studies are required to validate our findings.

Introduction Limited data is available about the outcomes of mechanical thrombectomy (MT) in stroke patients presenting with a large core infarct. We aim to investigate the safety and efficacy of MT in patients with large vessel occlusion and Alberta Stroke Program Early CT Score (ASPECTS) of 2-5. Methods Data from Stroke Thrombectomy and Aneurysm Registry (STAR), which combined the prospectively maintained databases of 28 thrombectomy-capable stroke centers in the US, Europe, and Asia, was interrogated. We identified thrombectomy patients presenting with an occlusion in the Internal carotid artery (ICA) or M1 segment of the middle cerebral artery (MCA). Multivariable regression analysis was performed to assess factors associated with favorable 90-day outcome (modified Rankin scale 0-3), including interaction terms between ASPECTS 2-5 and receiving MT in the extended window (≥ 6 hours from symptom-onset). Results Among MT patients who presented with ICA or M1 occlusion, 2132 had ASPECTS≥6 and 213 patients had ASPECTS 2-5. Patients in the low ASPECTS group were younger (70 vs. 72 years old, P=0.003) and more likely to present with an ICA occlusion (47.9% vs. 28.8%, P Conclusion More than one in three patients presenting with ASPECTS (2-5) may achieve favorable 90-day functional outcome following MT. Favorable outcome was 4 times higher in low ASPECTS patients who had successful recanalization. The effect of low ASPECTS on 90-day outcome did not differ in patients presenting in the early versus extended MT window. Disclosures E. Almallouhi: None. S. Al Kasab: None. Z. Hubbard: None. G. Porto: None. A. Alawieh: None. R. Chalhoub: None. E. Bass: None. P. Jabbour: None. R. Starke: None. S. Wolfe: None. A. Arthur: None. I. Maier: None. J. Grossberg: None. A. Rai: None. M. Park: None. J. Mascitelli: None. M. Psychogios: None. R. De Leacy: None. D. Raper: None. T. Dumont: None. M. Levitt: None. A. Polifka: None. J. Osbun: None. R. Crosa: None. J. Kim: None. W. Casagrande: None. M. Mokin: None. C. Matouk: None. A. Shaban: None. I. Fragata: None. A. Yoo: None. A. Spiotta: 1; C; Stryker, Penumbra, and Medtronic. 2; C; Penumbra, Stryker, Cerenovus, Terumo.

Introduction Chronic subdural hematoma (cSDH) is one of the most common neurosurgical diseases with an incidence of 1-5.3 cases per 100,000 that increases significantly with age. When symptomatic, these lesions are often treated by surgery, an approach which does not directly address the underlying pathophysiology of chronic inflammation and neovascularization of the dura and has a high incidence of recurrence. Middle meningeal artery (MMA) embolization has emerged as a potential minimally invasive endovascular treatment option that may substitute for surgery or serve as an adjunct. TRUFILL n-BCA is potentially well suited as a liquid embolic in this procedure given that it is non-caustic, rapidly deployed, and able to be injected in a highly targeted fashion. Here we present the protocol for a randomized clinical trial to evaluate the safety and effectiveness of n-BCA embolization of the MMA for the treatment of cSDH. Methods This investigational trial is a prospective, multi-center, open-label, randomized controlled study in which up to 376 subjects will be randomized to receive standard of care (SOC) alone or SOC and TRUFILL n-BCA MMA embolization for the treatment of cSDH. The study is designed to evaluate the effectiveness and safety of MMA in two cohorts - a surgical cohort and a non-surgical cohort. Results Study EndpointsThe primary study effectiveness endpoint is the incidence of residual or re-accumulation of the cSDH (>10 mm) at 6 months as assessed by an independent core laboratory OR re-operation or surgical procedure on the hematoma within 6 months post randomization. Secondary effectiveness endpoints include mean reduction of hematoma volume at 3, 6 and 12 months compared to baseline, reduction > 50% in hematoma volume at 3, 6 and 12 months as well as others. Secondary safety endpoints include death, stroke, myocardial infarction or thromboembolic complications within 3, 6 and 12 months as well as others. Secondary health economics endpoints include hospital days, intensive care unit days, and change in the EQ-5D-5L score at discharge and 6 months compared to baseline. Conclusion Middle meningeal artery embolization with n-BCA is an emerging treatment strategy for cSDH. An appropriately powered trial like the MEMBRANE Study will provide high level evidence on the potential safety and efficacy of this treatment paradigm. Disclosures C. Kellner: 1; C; Penumbra, Siemens, Cerebrotech, Viz.AI, Minnetronix. 4; C; Metis Innovative. F. Al-Mufti: None. R. Gupta: None. B. Jankowitz: None. R. Starke: None. A. Rai: None.

BackgroundAtrial fibrillation (AF) associated ischemic stroke is associated with worse functional outcomes, less effective recanalization, and increased rates of hemorrhagic complications after intravenous thrombolysis (IVT). Conversely, AF is not associated with hemorrhagic complications or functional outcomes in patients undergoing mechanical thrombectomy (MT). This differential effect of MT and IVT in AF associated stroke raises the question of whether bridging thrombolysis increases hemorrhagic complications in AF patients undergoing MT.MethodsThis international cohort study of 22 comprehensive stroke centers analyzed patients with large vessel occlusion (LVO) undergoing MT between June 1, 2015 and December 31, 2020. Patients were divided into four groups based on comorbid AF and IVT exposure. Baseline patient characteristics, complications, and outcomes were reported and compared.Results6461 patients underwent MT for LVO. 2311 (35.8%) patients had comorbid AF. In non-AF patients, bridging therapy improved the odds of good 90 day functional outcomes (adjusted OR (aOR) 1.29, 95% CI 1.03 to 1.60, p=0.025) and did not increase hemorrhagic complications. In AF patients, bridging therapy led to significant increases in symptomatic intracranial hemorrhage and parenchymal hematoma type 2 (aOR 1.66, 1.07 to 2.57, p=0.024) without any benefit in 90 day functional outcomes. Similar findings were noted in a separate propensity score analysis.ConclusionIn this large thrombectomy registry, AF patients exposed to IVT before MT had increased hemorrhagic complications without improved functional outcomes, in contrast with non-AF patients. Prospective trials are warranted to assess whether AF patients represent a subgroup of LVO patients who may benefit from a direct to thrombectomy approach at thrombectomy capable centers.

IntroductionThe endovascular stent-assisted coiling approach for the treatment of cerebral aneurysms is evolving rapidly with the availability of new stent devices. It remains unknown how each type of stent affects the safety and efficacy of the stent-coiling procedure.MethodsThis study compared the outcomes of endovascular coiling of cerebral aneurysms using Neuroform (NEU), Enterprise (EP), and Low-profile Visualized Intraluminal Support (LVIS) stents. Patient characteristics, treatment details and angiographic results using the Raymond–Roy grade scale (RRGS), and procedural complications were analyzed in our study.ResultsOur study included 659 patients with 670 cerebral aneurysms treated with stent-assisted coiling (NEU, n=182; EP, n=158; LVIS, n=330) that were retrospectively collected from six academic centers. Patient characteristics included mean age 56.3±12.1 years old, female prevalence 73.9%, and aneurysm rupture on initial presentation of 18.8%. We found differences in complete occlusion on baseline imaging, defined as RRGS I, among the three stents: LVIS 64.4%, 210/326; NEU 56.2%, 95/169; EP 47.6%, 68/143; P=0.008. The difference of complete occlusion on 10.5 months (mean) and 8 months (median) angiographic follow-up remained significant: LVIS 84%, 251/299; NEU 78%, 117/150; EP 67%, 83/123; P=0.004. There were 7% (47/670) intra-procedural complications and 11.5% (73/632) post-procedural-related complications in our cohort. Furthermore, procedure-related complications were higher in the braided-stents vs laser-cut, P=0.002.ConclusionsThere was a great variability in techniques and choice of stent type for stent-assisted coiling among the participating centers. The type of stent was associated with immediate and long-term angiographic outcomes. Randomized prospective trials comparing the different types of stents are warranted.

IntroductionAccurate estimation of the incidence of large vessel occlusion (LVO) is critical for planning stroke systems of care and approximating workforce requirements. This systematic review aimed to estimate the prevalence of LVO among patients with acute ischemic stroke (AIS), with emphasis on definitions and methods used by different studies.MethodsA systematic literature review was performed to search for articles on the prevalence of LVO and AIS. All articles describing the frequency of LVO frequency among AIS patients were included. Studies without consecutive recruitment or confirmation of LVO with CT angiography or MR angiography were excluded. Heterogeneity of the studies was assessed; meta-regression was performed to estimate the effect of LVO definition and study methods on LVO prevalence.Results18 articles met the inclusion criteria: 5 studies presented population based estimates; 13 provided single hospital experiences (5 prospective, 8 retrospective). The AIS denominator (number of all AIS) from which LVO rates were generated was variable. Nine different definitions were used, based on occlusion site. Significant heterogeneity existed among the studies (I2=99%, PConclusionThe heterogeneity of LVO estimates was remarkably high. The method of AIS denominator determination was the most significant predictor of LVO estimates. Studies with a standardized LVO definition and methods of AIS estimation are necessary to estimate the true prevalence of LVO among patients with AIS.

BackgroundPolymer coating embolism due to vascular medical device use is an increasingly recognized iatrogenic complication. This phenomenon has been linked with various adverse effects including neuroinflammation, acute ischemic stroke, cerebral hemorrhage, and death. Notably, procedure- and device-specific risks of this complication are poorly investigated. In this study, we evaluate the detectable frequency of intra-arterial polymer coating delamination among patients who underwent endovascular thrombectomy for treatment of acute ischemic stroke due to large vessel occlusion.MethodsNinety-two cerebral thrombectomy specimens were retrospectively analyzed for the presence of polymer coating particulates. Histologic findings were correlated with demographic and procedural details and patient outcomes.ResultsEvidence of polymer coating deposition was found in 30 of 92 extracted thrombi (33%). No correlation between intrathrombus polymer deposition and use of a specific thrombectomy device such as a stent retriever, aspiration catheter, or guide catheter was found. However, heterogeneous patterns of device use suggest a number of culprit devices. A trend toward longer procedure times and multiple thrombectomy passes was noted in positive cases. Intrathrombus polymer deposition was not associated with adverse clinical outcomes as measured by the 90-day modified Rankin Scale (mRS); however, small sample size and follow-up intervals limit interpretation. Ninety-day outcomes based on mRS may not fully capture the clinical effects of acute and/or delayed intracerebral polymer complications.ConclusionIn light of documented adverse neurologic effects, the frequency of intrathrombus polymer particulates indicates the need for consensus testing methods and large-scale long-term prospective clinical device trials, with inclusion of relevant endpoints to better assess biomaterial and device risks to patients.

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.

Endovascular thrombectomy (ET) for acute ischemic stroke is the current standard of care. Although successful ET has high efficacy in improving functional outcomes, the decision to abort a long procedure remains a challenge. Longer procedure time (PT) has been associated with lower rates of functional independence.The objective of this study was to evaluate the impact of PT on outcomes and complications after ET using different techniques at a multicenter level and to define the risk of procedure extension in different patient cohorts.Patients undergoing ET with a stent retriever (SR) or a direct aspiration at first pass technique at 7 U.S. centers between June 2013 and February 2018 were reviewed from prospectively maintained databases that include baseline variables and technical and clinical outcomes. Multivariate analyses were used to assess impact of PT on 90-day modified Rankin scores, successful recanalization, post-procedural symptomatic hemorrhage (sICH), and complications.The study included 1,359 patients and demonstrated a decreased likelihood of good functional outcomes (modified Rankin score 0 to 2) when PT extended beyond 30 min (p 0.01). Rates of sICH and complications increased exponentially with PT (doubling rates of 26 and 50 min, respectively). The cumulative rate of successful recanalization and good outcomes plateaued after 60 min of PT. In patients with PT30 min, fewer attempts predicted the success of ET and good outcomes (p 0.01). Successful recanalization was achieved faster with the direct aspiration at first pass technique than in SR. The direct aspiration technique was more sensitive to PT than SR, and posterior stroke was more sensitive to PT than anterior stroke.Longer ET procedures lead to lower rates of functional independence and higher rates of sICH and complications. Exceeding 60 min or 3 attempts should trigger careful assessment of futility and risks of continuing the procedure.

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.

BackgroundThe efficacy of endovascular thrombectomy (ET) for acute ischemic stroke (AIS) in octogenarians is still controversial.ObjectiveTo evaluate, using a large multicenter cohort of patients, outcomes after ET in octogenarians compared with younger patients.MethodsData from prospectively maintained databases of patients undergoing ET for AIS at seven US-based comprehensive stroke centers between January 2013 and January 2018 were reviewed. Demographic, procedural, and outcome variables were collected. Outcomes included 90-day modified Rankin Scale (mRS) score, postprocedural National Institutes of Health Stroke Scale score, postprocedural hemorrhage, and mortality. Univariate and multivariate analyses were performed to assess the independent effect of age ≥80 on outcome measures. Subgroup analyses were also performed based on location of stroke, success of recanalization, or ET technique used.ResultsRates of functional independence (mRS score 0–2) after ET in elderly patients were significantly lower than for younger counterparts. Age ≥80 was independently associated with increased mortality and poor outcome. Age ≥80 showed an independent negative prognostic effect on outcome even when patients were divided according to thrombectomy technique, location of stroke, or success of recanalization. Age ≥80 independently predicted higher rate of postprocedural hemorrhage, but not success of recanalization. Baseline deficit and number of reperfusion attempts, but not Thrombolysis in Cerebral Infarction score were associated with lower odds of good outcome.ConclusionThe large effect size of ET on AIS outcomes is significantly diminished in the elderly population when using comparable selection criteria to those used in younger counterparts. This raises concerns about the risk–benefit ratio and the cost-effectiveness of performing this procedure in the elderly before optimizing patient selection.

* on behalf of the Stroke Thrombectomy and Aneurysm Registry (STAR) Collaborators Introduction: Intravenous thrombolysis complications are enriched in AF associated stroke, as these patients have worse functional outcomes, less effective recanalization, and increased rates of hemorrhagic complications. These data suggest that AF patients may be at particularly high risk for complications of bridging therapy for large vessel occlusions treated with mechanical thrombectomy (MT). Here we determine whether clinical outcomes differ in AF associated stroke treated with MT and bridging therapy. Methods: We performed a retrospective cohort study of the Stroke and Aneurysm Registry (STAR) from January 2015 to December 2018 and identified 4,169 patients who underwent MT for an anterior circulation stroke, 1,517 (36.4 %) of which had comorbid AF. Prospectively defined baseline characteristics and clinical outcomes were compared. Results: Hemorrhagic complications after MT were similar in patients with or without AF. In patients without AF, bridging therapy improved 90-day outcomes (aOR 1.32, 1.02-1.74, p Conclusions: Bridging therapy in AF patients undergoing thrombectomy independently increased the odds of intracranial hemorrhage and did not improve functional outcomes. AF patients may represent a high-risk subgroup for thrombolytic complications. Randomized trials are warranted to determine whether patients with AF associated stroke may benefit by deferring bridging therapy at thrombectomy-capable centers.

Introduction: Previous studies have reported that Hispanic stroke patients have limited access to mechanical thrombectomy (MT) compared to other ethnic groups. This has resulted in worse stroke outcomes in this group. However, limited data is available about the outcomes of MT in Hispanic patients. Methods: We used data from the Stroke Thrombectomy and Aneurysm Registry (STAR) that combined the prospectively maintained databases of 28 thrombectomy-capable stroke centers in the US, Europe, and Asia. Consecutive patients who underwent MT were included in these analyses and patients were divided into 2 groups (Hispanics vs. non-Hispanics). Baseline features, time from symptom onset, thrombolysis receipt, final thrombolysis in cerebral infarction (TICI) score, symptomatic hemorrhage, and 90-day functional outcomes (measured by modified Rankin scale-mRS) were compared between Hispanic and non-Hispanics patients. A generalized linear model with logit link was used to assess the relationship between ethnicity and favorable outcomes at 90-day (mRS 0-2) controlling for confounders. Results: We included 2015 patients in these analyses. Of those, 285 (14.1%) were Hispanic. As shown in table 1, Hispanic patients were older (72 vs. 70, p=0.007), more likely to have diabetes (41.1% vs. 26.5%, p Conclusion: Hispanic patients receiving MT have higher rate of stroke risk factors including diabetes and hypertension. Moreover, Hispanic ethnicity was independently associated with lower probability of favorable 90-day outcome.

Introduction: Recent trials have proven safety and efficacy of mechanical thrombectomy for patients presenting with emergent large vessel occlusion beyond 6 hours of symptom onset. While evidence supports using baseline CT scan to evaluate the candidacy for mechanical thrombectomy for patients presenting in the early window, late window trials have used advanced imaging such as CT and MR perfusion. We aim to assess outcomes of MT stratified by admission Alberta Stroke Program Early CT Score (ASPECTS). Methods: We used data from the prospectively maintained registries of 28 stroke centers in the Stroke Thrombectomy and Aneurysm (STAR) collaboration. Demographics, comorbidities, LVO site, ASPECTS, MT technique, radiographic and clinical outcome data were collected. Patients with M1 or ICA occlusion were included in these analyses. Multivariable analysis was performed using a generalized linear model with logit link to assess for variables associated with favorable outcomes. Results: 3356 patients in the STAR database were reviewed and 347 (10.3%) of those underwent MT in the late window (table). Median age was 69, 189 (54.5%) were female, and 181 (52.2%) were white. 295 patients ASPECTS ≥6. In this group, 200 (68.8%) had M1 occlusion, and the remaining had ICA occlusion. Aspiration thrombectomy was used in 139 (47.1%) of patients. Successful reperfusion was achieved (mTICI≥2b) in 264 (76.1%). sICH was observed in 15 (5.1%). Excellent functional outcome (mRS 0-2) was observed in 124 (42%) patients. ASPECTS score was independently associated with favorable outcomes (aOR 1.2, 95% CI 1.1-1.4, P=0.006). Conclusion: Excellent outcomes are observed in patients with good ASPECT score presenting in the late window irrespective of perfusion criteria. Admission CT scan could be used to triage patients presenting with emergent large vessel occlusion beyond 6 hours of symptom onset.

Background/Objective: Blood pressure parameters for patients undergoing mechanical thrombectomy (MT) are not clearly defined. Prior studies have shown that higher maximum and mean systolic blood pressure (SBP) is associated with adverse outcomes. Our study sought to investigate the relationship of blood pressure on clinical outcomes after successful revascularization and determine optimal thresholds for BP parameters that correlated with a poor functional outcome. Methods: This was a retrospective observational study of 88 consecutive patients who received successful MT at one comprehensive stroke center. Systolic, diastolic, and mean arterial pressure values were recorded for each patient over a 48-hour period, as well as patient age and National Institutes of Health Stroke Scale (NIHSS). Outcome measures included modified Rankin Score (mRS), intracranial hemorrhage (ICH), and mortality at time of discharge and 90 days. Both univariable and multivariable logistic regression analysis was performed to identify associations between the BP covariates and functional outcomes. Results: A higher SBP standard deviation (SD) of >14mmHg (OR=1.150) and wider SBP range >64mmHg (OR=1.037) from the mean in the first 48 hours after successful MT were associated with poor MRS at 90 days. A SBP SD>14 was also associated with mortality at 90 days. A higher age (OR=1.052) and NIHSS (OR=1.096) were also associated with a poor MRS at 90 days. A higher DBP mean (OR=1.045) was associated with a higher rate of hemorrhagic transformation (HT). Conclusions: A higher SBP variability within the first 48 hours after successful MT is associated with a higher likelihood of poor 90-day functional outcome and mortality, and a higher mean DBP is associated with a higher rate of HT.

BackgroundThe PerfusiOn imaging Selection of Ischemic sTroke patIents for endoVascular thErapy (POSITIVE) trial was designed to evaluate functional outcome in patients with emergent large vessel occlusion (ELVO) presenting within 0–12 hours with pre-specified bifurcated arms of early and late window presentation, who were selected for endovascular thrombectomy with non-vendor specific commercially available perfusion imaging software. Recent trials demonstrating the benefit of thrombectomy up to 16–24 hours following ELVO removed equipoise to randomize late window ELVO patients and therefore the trial was halted.MethodsUp to 200 patients were to be enrolled in this FDA-cleared, prospective, randomized, multicenter international trial to compare thrombectomy and best medical management in patients with ELVO ineligible for or refractory to treatment with IV tissue plasminogen activator (IV-tPA) selected with perfusion imaging and presenting within 0–12 hours of last seen normal. The primary outcome was 90-day clinical outcome as measured by the raw modified Rankin Scale (mRS) with scores 5 and 6 collapsed (mRS shift analysis).ResultsThe POSITIVE trial suspended enrollment with the release of results from the DAWN trial and was stopped after the release of the DEFUSE 3 trial results. Thirty-three patients were enrolled (21 for medical management and 12 for thrombectomy). Twelve of the 33 patients were enrolled in the 6–12 hour cohort. Despite the early cessation, the primary outcome demonstrated statistically significant superior clinical outcomes for patients treated with thrombectomy (P=0.0060). The overall proportion of patients achieving an mRS score of 0–2 was 75% in the thrombectomy cohort and 43% in the medical management cohort (OR 4.00, 95% CI 0.84 to 19.2).ConclusionPOSITIVE supports the already established practice of delayed thrombectomy for appropriately selected patients presenting within 0–12 hours selected by perfusion imaging from any vendor. The results of the POSITIVE trial are consistent with other thrombectomy trials. The statistically significant effect on functional improvement, despite the small number of patients, reinforces the robust benefits of thrombectomy.Clinical trial registrationNCT01852201

The most common intracranial large vessel occlusion encountered in acute stroke patients presenting for consideration for mechanical thrombectomy involves the M1 segment of the MCA. Interventionalists performing endovascular stroke procedures must possess a thorough understanding of the various treatment strategies that can be utilized to revascularize the occluded M1. Using case examples, these treatment options are presented and discussed.

There has been increasing adoption of endovascular stroke treatment in the United States following multiple clinical trials demonstrating superior efficacy. Next steps in enhancing this treatment include an analysis and development of stroke systems of care geared toward efficient delivery of endovascular and comprehensive stroke care. The chapter presents epidemiological data and an overview of the current state of stroke delivery and potential improvements for the future in the light of clinical data.

International audience; Abstract BACKGROUND Randomized controlled trials evaluating mechanical thrombectomy (MT) for acute ischemic stroke predominantly studied anterior circulation patients. Both procedural and clinical predictors of outcome in posterior circulation patients have not been evaluated in large cohort studies. OBJECTIVE To investigate technical and clinical predictors of functional independence after posterior circulation MT while comparing different frontline thrombectomy techniques. METHODS In a retrospective multicenter international study of 3045 patients undergoing MT for stroke between 06/2014 and 12/2018, 345 patients had posterior circulation strokes. MT was performed using aspiration, stent retriever, or combined approach. Functional outcomes were assessed using the 90-d modified Rankin score dichotomized into good (0-2) and poor outcomes (3-6). RESULTS We included 2700 patients with anterior circulation and 345 patients with posterior circulation strokes. Posterior patients (age: 60 ± 14, 46% females) presented with mainly basilar occlusion (80%) and were treated using contact aspiration or ADAPT (39%), stent retriever (31%) or combined approach (19%). Compared to anterior strokes, posterior strokes had delayed treatment (500 vs 340 min, P

BackgroundThe coronavirus disease (COVID-19) pandemic has affected stroke care globally. In this study, we aim to evaluate the impact of the current pandemic on racial disparities among stroke patients receiving mechanical thrombectomy (MT).MethodsWe used the prospectively collected data in the Stroke Thrombectomy and Aneurysm Registry from 12 thrombectomy-capable stroke centers in the US and Europe. We included acute stroke patients who underwent MT between January 2017 and May 2020. We compared baseline features, vascular risk factors, location of occlusion, procedural metrics, complications, and discharge outcomes between patients presenting before (before February 2020) and those who presented during the pandemic (February to May 2020).ResultsWe identified 2083 stroke patients: of those 235 (11.3%) underwent MT during the COVID-19 pandemic. Compared with pre-pandemic, stroke patients who received MT during the pandemic had longer procedure duration (44 vs 38 min, P=0.006), longer length of hospitalization (6 vs 4 days, PConclusionThe COVID-19 pandemic has affected the care process for stroke patients receiving MT globally. There is a significant decline in the number of African American patients receiving MT, which mandates further investigation.

Introduction Mechanical Thrombectomy (MT) is the standard of care for patients presenting with emergent large vessel occlusion (ELVO) with salvageable tissue. A subgroup of ELVO is refractory to reperfusion due to underlying intracranial atherosclerosis (ICAS), often requiring rescue therapy with balloon angioplasty, stenting or both. Whether such rescue therapy is safe and effective remains to be established. The purpose of this study is to investigate the safety, efficacy, and long-term outcomes of MT for ELVO related ICAS. Methods We queried the databases of 11 thrombectomy-capable centers in the US and Europe included in STAR (Stroke Thrombectomy and Aneurysm Registry). In this analysis, we included patients who underwent rescue therapy (balloon angioplasty and/or stenting) in the setting of ELVO due to underlying ICAS. A matched sample was produced by matching on the variables of age, admission NIHSS, and location of the occlusion. Results Out of 2827 thrombectomy patients included in STAR at the time of this analysis, 190 patients required rescue therapy for ELVO with underlying ICAS. Balloon angioplasty was performed on 116 patients, and 113 patients had intracranial stenting. On multivariate analysis, after controlling for age, sex, race, hypertension, diabetes, prior stroke, NIHSS on admission and location of occlusion; compared to angioplasty alone, or stenting alone, combination therapy with angioplasty and stenting was associated with higher odds of favorable long-term functional outcome (mRS 0–2) (OR 4.404, 95% CI 1.318–9.712; P=0.021).in the matched analysis, 161 rescue therapy patients matched to a similar number of controls. There was no difference in age, race, sex, rate of IV tPA administration, ASPECTS score, or onset to groin time. Successful first attempt rate was lower (52% vs. 22%, p=0.001) and procedural time was longer in the rescue therapy group (47 min vs. 31 min, p≤0.001). There was no difference in symptomatic intracranial hemorrhage (7.5% vs. 5.6%, p=0.49), or favorable long term functional outcome (modified Rankin scale 0–2) (42.2% vs. 50.9%, p=0.118) between patients in the rescue therapy and control groups. Conclusion In patients with ELVO with underlying ICAS requiring rescue therapy, despite longer procedural time and lower rate of first pass revascularization, rescue therapy appears to be safe with similar rate of favorable long-term functional outcomes compared to patients with large vessel occlusion from embolic source. Disclosures S. Al Kasab: None. E. Almallouhi: None. I. Maier: None. A. Arthur: None. J. Kim: None. R. De Leacy: None. A. Rai: None. S. Keyrouz: None. K. Fargen: None. T. Dumont: None. P. Kan: None. R. Starke: None. A. Spiotta: None.

Background Advances in stroke care like most innovations in medicine have happened gradually, over time, in increments and have typically benefitted from the collaborative efforts of a diverse group with a common goal. The CLOT summit inaugurated in 2015 created an ecosystem guided by these principles to evaluate and develop pathways for enhancing stroke care. Methodology Three core groups are invited to participate. These include scientists involved in clot research, engineers involved in device development and physicians involved in interventional and medical treatment of acute ischemic stroke. The initial format followed a focused group discussion and presentation on key topics leading to development of targeted projects. In subsequent years the outcome from previous year’s summit was evaluated and a future course in basic and clinical research charted. A key clinical component was improving procedural performance and defining unmet needs. Results To date, the output has covered several areas. Basic clot research: ex vivo clot analysis resulted in five registries in the US (one) and the EU (four) with the aim of multicenter collection of thrombectomy specimen with centralized analysis. This has yielded several publications in the JNIS and elsewhere. Procedure optimization: Pre-intervention imaging analysis involved multiple contributions on thrombus imaging using CT/CTA/MR. In-Vitro modeling for thrombectomy procedures centered around procedural aspects (tortuosity, the effects of flow and pressure, embolization to new territory) and clot interaction (fibrinous or calcified clots versus friable clots). Progress in device iteration was part of procedure optimization based on in-vitro modeling and review of challenging cases highlighting a potential unmet solution. Clinical Studies: These were a product of the first two and involve clinical studies related to new devices and clinical registry for calcified clots. Conclusion The CLOT summit represents a novel incubator platform bringing together expertise in a coordinated fashion that has resulted in meaningful basic and clinical contribution to the evolving stroke care. Key outcomes of the summit over the first 5-years are presented. Disclosures A. Rai: 2; C; Cerenovus, Microvention, Stryker Neurovascular. J. Fiehler: 2; C; Cerenovus. R. McCarthy: None. A. Siddiqui: 2; C; Cerenovus. D. Liebeskind: 2; C; Cerenovus. W. Hacke: 2; C; Cerenovus.

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.

Introduction Acute ischemic strokes (AIS) due to large vessel occlusion (LVO) occur more frequently in elderly patients, resulting in more severe symptoms and worse outcomes after treatment. The purpose of this study is to evaluate the age-dependent outcomes of Endovascular Thrombectomy (ET) in the real world, using a large dataset from the Stroke Thrombectomy and Aneurysm Registry (STAR). Methods All patients undergoing endovascular thrombectomy for AIS at 12 comprehensive stroke centers between January 2013 and December 2018 were included. Data were retrospectively collected by reviewing patient charts and procedure notes. The primary endpoint was the modified Rankin Score (mRS) at 90-days after the procedure, which was dichotomized into good outcome (mRS 0–2) or poor outcome (mRS 3–6). Results Out of the 3850 patients that underwent mechanical thrombectomy, 2,827 patients (mean age 69±14, 49% female) had 90-day follow-up and were included in this study. When adjusting for confounding variables using multivariate logistic regressions, increased age was found to be an independent predictor of poor outcome (OR=1.4, p Conclusion Higher age is an independent predictor of worse outcome and increased mortality in patients undergoing ET for AIS. Baseline deficits, ASPECT score, and number of attempts, but not complete revascularization rates, were associated with better outcomes in elderly patients. Our findings underline the need for further refinement of selection criteria for elderly patients being considered for ET. Disclosures R. Chalhoub: None. A. Alawieh: None. S. Kasab: None. D. Pullmann: None. A. Arthur: None. J. Kim: None. R. De Leacy: None. M. Psychogios: None. I. Maier: 6; C; Microvention, Cerenovus. A. Rai: 6; C; Stryker Neurovascular, Microvention, Cerenovus. S. Keyrouz: 6; C; PORTOLA. K. Fargen: 6; C; Cerebrotech Medical. R. Starke: 1; C; NREF, Joe Niekro Foundation, Brain Aneurysm Foundation, BEE Aneurysm Foundation, NIH. 6; C; Penumbra, Medtronic, Cerenovus, InNeuroCo, Abbott. A. Spiotta: 1; C; Penumbra. 6; C; Penumbra, Cerenovus.

Introduction Early studies have shown that using intra-arterial thrombolysis is effective in achieving recanalization in patients with acute ischemic stroke. However, the using intraarterial thrombolysis was associated with a high rate of symptomatic hemorrhagic transformation (sICH). In current practice time, intra-arterial thrombolysis using tissue plasminogen activator (IA-tPA) can be used as an adjunctive technique in the setting of persistent distal occlusion during mechanical thrombectomy (MT). Methods We used data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which included the prospectively maintained databases from 28 thrombectomy-capable stroke centers in the US, Europe, and Asia. We included only consecutive patients who received MT using second generation thrombectomy devices. Then, we identified patients who received 5–10 mg of IA-tPA injected directly to the target vessel because of persistent distal occlusion during MT. We collected the baseline characteristics, procedural metrics, rate of sICH, and long-term functional outcomes. We estimated a Generalized Linear Model (GLM) with logit link to assess predictors of sICH, successful recanalization (Thrombolysis in Cerebral Infarction score≥2b), and favorable 90-day functional outcomes (modified Rankin scale 0–2 at 90-day). Results A total of 154 patients received IA-tPA out of 1608 thrombectomy patients who were included in this analysis. Median age was 68 (IQR 57–76) years; 79 (51.3%) were females; 97 (63%) were white. There was no difference in stroke severity measured by the National Institute of Health stroke scale (NIHSS) (17 vs. 15, P=0.079) or Alberta Stroke Program Early CT (ASPECT) score (9 vs. 9, P=0.16) between patients in the IA-tPA group compared to the non-IA-tPA group, respectively. In addition, no difference was noted in the prevalence of stroke risk factors (hypertension, diabetes, atrial fibrillation, prior stroke) between both groups. IA-tPA group had less patients who have received IV-tPA (33.8% vs. 54.9%, P Conclusion The use of IA-tPA as an adjunctive treatment to mechanical thrombectomy due to persistent distal occlusion did not result in a higher rate of successful recanalization, 90-day functional independence, or sICH. Disclosures E. Almallouhi: None. S. Al kasab: None. A. Alawieh: None. M. Psychogios: None. A. Arthur: 1; C; Microvention, Penumbra, and Siemens;. 2; C; Balt, Johnson and Johnson, Leica, Medtronic, Microvention, Penumbra, Scientia, Siemens, and Stryker. 4; C; Bendit, Cerebrotech, Endostream, Magneto, Marblehead, Neurogami, Serenity, Synchron, Triad Medical and Vascular Simulations. J. Kim: None. R. De Leacy: 2; C; Cerenovus, Imperative Care and Siemens. A. Rai: None. S. Keyrouz: None. K. Fargen: None. T. Dumont: None. P. Kan: None. R. Starke: 2; C; Penumbra, Abbott, Medtronic, InNeuroCo and Cerenovus. A. Spiotta: 1; C; Penumbra. 2; C; Penumbra, Stryker, Cerenovus, Terumo.

Introduction: Previous research reported higher prevalence of vascular risk factors and worse outcomes after stroke in non-white patients compared to whites. Whether similar results still apply in the post mechanical thrombectomy era remains unknown. Methods: The STAR registry combined the prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe, and Asia. Consecutive patients who underwent MT were included in these analyses. Baseline features, risk factors, location of occlusion, time from symptom onset, tPA receipt, procedural complication rates, symptomatic hemorrhage, and long-term functional outcome were compared between white and non-white patients. Multivariate logistic regression analysis was performed to evaluate the impact of race on long-term outcome. Results: Total of 2,284 patients were included in this analysis. Of those, 1,436 (62.9%) were white. Baseline features and outcomes are summarized in table 1. Non-white patients were older ( 71 Vs 66, p= Conclusion: In this study, white race was independent predictor of good 90-day outcome. This finding could be due to higher prevalence of vascular risk factors in non-white patients.

Introduction: Stroke thrombectomy devices and the experience of neurointerventionists have improved significantly over the last few years making targeting distal occlusions such as of the M2 segment of the middle cerebral artery more feasible. We aimed to study the trend in the successful first pass (SFP) of M2 occlusions over time using the data from a contemporary multicenter registry. Methods: We reviewed the data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which included data from 11 thrombectomy-capable stroke centers to identify stroke patients who underwent mechanical thrombectomy of M2 segment occlusion. SFP was defined by achieving modified Thrombolysis in Cerebral Infarction (mTICI) score≥2b with a single thrombectomy device pass. We analyzed the linear trendline of the rate of SFP over time. Then, we used a logistic regression model to assess predictors of SFP of M2 segment occlusion. Results: We included 401 patients who underwent stroke thrombectomy of M2 occlusion; median age was 71 (IQR 60-80), 212 (52.9%) were females, 174 (43.4%) were white, National Institute of Health stroke scale (NIHSS) was 14 (IQR 8-19), Alberta Stroke Program Early CT (ASPECT) score on presentation was 9 (IQR 7-10) and onset wot groin time was 287 (IQR 181-454). SFP was achieved in 118 (29.4%) patients (linear trendline over time is in Figure 1). Presenting after 2014 was an independent predictor of SFP (OR 1.9, 95% CI 1.1-3.2, P=0.019) after controlling for age, sex, NIHSS on presentation, intravenous alteplase (IV-tPA), and onset to groin time. Conclusion: SFP rate of M2 segment occlusion has increased after 2014 likely secondary the improvement in stroke thrombectomy devices and neurointerventionists experience.

Introduction: Mechanical thrombectomy (MT) is the current standard of care treatment for patients presenting with severe symptoms due to large vessel occlusion (LVO); approximately 30% of patients with LVO however present with mild symptoms (NIHSS < 6). The safety and efficacy of MT in this group has not yet been established. The purpose of this study is to evaluate the safety of MT in patients presenting with mild symptoms due to LVO in a large multicenter registry. Methods: STAR registry combined the prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe and Asia. Patients who underwent MT were included in these analyses. Baseline features, risk factors, location of occlusion, time from symptom onset, tPA receipt, procedural complication rates, symptomatic hemorrhage, and long-term functional outcome were compared between patients with mild symptoms (NIHSS < 6) to those with severe symptoms (NIHSS ≥ 6). Results: Total of 2,114 patients were included in this analysis. Of those, 162 patients presented with NIHSS ≥ 6. Baseline features and outcomes are summarized in table 1. There was no difference in age, or sex, tPA receipt, number of attempts, rate of successful revascularization, symptomatic hemorrhage, or length of hospital stay. Median ASPECTS score was 9 in the mild Vs 8 in the severe symptom group (p=< 0.001), there was a higher percentage of patients in the mild symptom group with hypertension, hyperlipidemia, and LVO in the posterior circulation. Conversely there were more patients with atrial fibrillation in the severe symptom group. Excellent outcome (mRS 0-2 at 90 days) was achieved in 69.8% patients in the mild group compared to 38.3% in the severe group, p= Conclusion: In patients with minor symptoms due to large vessel occlusion, mechanical thrombectomy appears to be safe with low complication rates. Approximately seventy percent of patients achieved excellent functional recovery. Table 1

Introduction: Aspiration thrombectomy using the ADAPT technique has been shown to have similar efficacy to stent retriever thrombectomy (SRT) in randomized trials of proximal large vessel occlusions. In this work, we investigated the differences in technical and clinical outcomes between ADAPT and SRT for distal vessel occlusions from the Stroke Thrombectomy and Aneurysm Registry (STAR). Methods: Patients undergoing thrombectomy for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics for patients with isolated distal artery occlusion including MCA2, MCA3/4, ACA1/2, and PCA2/3. Clinical endpoint was the modified Rankin score (mRS) at 90-days, and technical outcomes were procedure time, total attempts, and mTICI scores. Results: A total of 464 patients (mean age 69±13.5 years) were treated with ADAPT (56%) or SRT (44%) for distal occlusions during the study period. Patients in the ADPAT group were mainly treated using 3MAX (36%), 4MAX (21%), ACE68/64 (20%), 5MAX/ACE (12%). SRT group included the use of Trevo (50%), Solitaire (44%), or both (5%). There were no significant differences in rates of good outcomes or successful recanalization between ADAPT and SRT groups on multivariate logistic regression analysis controlling for significant confounding variables (p>0.1). Use of SRT in distal occlusions was an independent predictor of longer procedure times compared to ADAPT on linear regression (coefficient=23, p Conclusions: Both SRT and ADAPT thrombectomy lead to comparable rates of favorable outcome for distal vessel occlusion. SRT requires longer procedures and may be associated with higher rates of hemorrhage. Further randomized trials are needed to confirm whether either techniques may provide a better safety or efficacy profile in distal vessel occlusions.

Introduction: Endovascular thrombectomy (ET) for treating acute stroke in the real-world has expanded beyond the selection criteria used in major trials, and currently includes posterior circulation strokes. Posterior circulation stroke is believed to have worse outcomes than anterior circulation stroke, and its outcomes following ET are still being studied. We explored the major determinants of functional recovery after ET for posterior circulation stroke in a large cohort of patients from the Stroke Thrombectomy and Aneurysm Registry (STAR). Methods: STAR includes patients undergoing ET for acute ischemic stroke at 12 comprehensive stroke centers in the US and globally. Data on patient demographics, technical and clinical outcomes was reviewed retrospectively from patient charts and procedure notes. Primary outcomes was the modified Ranking Score (mRS) at 90 days dichotomized into favorable (mRS 0-2) and poor outcome (mRS 3-6). Results: A total of 3850 patients were reviewed, of which 345 patients (mean age 60±14) were treated for posterior circulation stroke with predominantly basilar artery occlusion (80%). Patients were treated using aspiration thrombectomy (ADAPT, 39%), stent retriever thrombectomy (31%), combined approach (19%) or intracranial stenting (7%). The overall rate of favorable outcome was 33%. Patients with diabetes, high NIHSS on admission, and proximal occlusions had significantly higher odds of poor functional outcomes on multivariate analysis (p Conclusions: Despite similar rates of functional recovery after ET for anterior circulation stroke between stent retriever and ADAPT, our analysis demonstrates that in posterior circulation stroke, ADAPT may lead to better functional outcomes compared to stent retriever without differences in safety profiles.

Introduction: Clinical trials have proven the safety and efficacy of mechanical thrombectomy (MT) with intravenous alteplase (tPA) compared to tPA alone in patients presenting with large vessel occlusion (LVO). The impact of tPA prior to MT on procedural metrics, successful revascularization, symptomatic hemorrhage and long-term functional outcome has not been established from large scale real-world studies. In this study we evaluate the impact of tPA prior to MT on procedural times, immediate and long-term outcomes. Methods: The STAR registry combined prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe and Asia. Patients who received mechanical thrombectomy with or without intravenous tPA prior to MT were included in these analyses. Baseline characteristics, procedural time, successful revascularization (TICI ≥ 2B), symptomatic intracranial hemorrhage (PH2), and long-term functional outcomes were compared between the two groups. Results: Total of 1869 patients were included in this analysis. Of those, 907 received tPA prior to MT. Baseline features and outcomes are summarized in table 1. There were more white patients in the non-tPA group, and more patients in this group had atrial fibrillation and hyperlipidemia; otherwise there were no differences in baseline features between the two groups. Median NIHSS on admission was 16 in both groups, median ASPECTS was 9 in the tPA group versus 8 in the non-tPA group, p=0.208. Patients in the tPA group had higher rate of successful revascularization, lower number of revascularizations attempts and were more likely to achieve excellent long-term functional outcome. There was no difference in procedural time, rate of symptomatic hemorrhage or length of hospital stay. Conclusion: Bridging therapy with intravenous tPA prior to mechanical thrombectomy may facilitate MT and yield to better long-term functional outcome.

Background: Standard mechanical thrombectomy (MT) techniques utilized include aspiration thrombectomy (ADAPT), stent retriever (SR), and a combination of both (Solumbra). Many studies compare outcomes between ADAPT and SR; however, there has yet to be a large multicenter investigation comparing ADAPT and SR to Solumbra. Methods: All patients from the participating STAR collaboration who underwent MT from 2015-2019 were included. Patients were analyzed by first MT technique utilized (ADAPT, SR, or Solumbra). Univariable and multivariable linear regression was utilized to analyze the MT technique association to number of thrombectomy attempts and procedure time. Univariable and multivariable logistic regression was utilized to determine the association between MT technique and the following outcomes: recanalization, symptomatic hemorrhage, 90-day functional independence, or 90-day mortality. P value less than 0.5 was considered significant. Results: A total of 2515 MT for stroke were identified: 1155 (46%) ADAPT, 735 (29%) SR, 625 (25%) Solumbra. Patients who received Solumbra MT were older (p Conclusion: Compared to standard ADAPT and SR thrombectomy, the Solumbra technique for MT is a longer procedure that results in an increased likelihood of hemorrhage and 90-day mortality.

Introduction: Mechanical Thrombectomy (MT) is currently the standard of care for patients presenting with emergent large vessel occlusion (ELVO) with salvageable tissue. A subgroup of patients with ELVO are found to have refractory occlusion due to underlying intracranial atherosclerosis (ICAS), often requiring angioplasty with or without stenting. Whether this treatment is safe or effective in this group of patients remains to be established. The purpose of this study is to investigate the safety, efficacy and long-term outcome of MT with rescue therapy in patients with ICAS. Methods: STAR registry combined prospectively maintained databases of 11 thrombectomy-capable centers in the US, Europe and Asia. In this analysis, we included patients who underwent rescue balloon angioplasty and/or stenting in the setting of ELVO. A matched sample was produced by matching on the variables of age, admission NIHSS, and location of occlusion. Results: Out of 2827 thrombectomy patients included in STAR registry, 190 patients received MT and required rescue angioplasty and/or stenting. Balloon angioplasty was performed on 116 patients, and 84 patients had intracranial stenting. Compared to the 161 ICAS patients matched to similar number of controls. There was no difference in age, race, sex, rate of IV tPA administration, ASPECTS score, or onset to groin time. Successful first attempt was higher in patients with embolic LVO (22 vs 52, p=0.001), procedural time was longer in patients with ICAS (47 min Vs 31 min, p= Conclusion: In patients with ELVO with underlying ICAS requiring rescue angioplasty and/or stenting; despite longer procedural time and lower rate of first pass revascularization, rescue therapy appears to be safe with similar complication rates and long-term functional outcomes compared to patients with large vessel occlusion from embolic source. Table 1

Introduction: Intra-arterial tissue plasminogen activator (IA-tPA) can be used as rescue therapy during mechanical thrombectomy for stroke patients, mostly in the setting of distal occlusion. The outcomes of IA-tPA has not been assessed in large-scale multi-center studies yet. Methods: We used data from the Stroke Thrombectomy and Aneurysm Registry (STAR), which included prospectively maintained databases of 11 thrombectomy-capable stroke centers in the US, Europe, and Asia. We compared the baseline characteristics, procedural metrics, rate of symptomatic intracranial hemorrhage (sICH), and long-term functional outcomes between thrombectomy patients who received rescue IA-tPA and a control group of thrombectomy patients with matched age, National Institute of Health stroke scale (NIHSS) on presentation, location of occlusion and IV-tPA receipt. Results: A total of 2827 thrombectomy patients were included in the STAR registry. Out of those, 205 patients received IA-tPA. We matched 191 patients from the IA-tPA group with a control group of 191 patients (table 1). No difference was seen in age, sex, race, vascular risk factors, or Alberta Stroke Program Early CT (ASPECT) score between both groups. In addition, procedural metrics, including onset to groin time, the procedure duration, and rate of successful recanalization (modified Thrombolysis in Cerebral Infarction score≥2b) were similar. Finally, similar outcomes were noted in both groups, including the rate of sICH and good 90-day functional outcome (modified Rankin scale≤2). Conclusion: The use of IA-tPA as an adjunctive treatment to mechanical thrombectomy was safe but did not result in a higher rate of successful recanalization or good long-term functional outcomes.

Introduction: Recently completed randomized controlled trials comparing aspiration thrombectomy (ADAPT) to stent retriever thrombectomy (SRT) demonstrated similar clinical outcomes, but faster thrombectomy procedure time in the ADAPT group. This study evaluates the difference in technical outcomes between ADAPT and SRT combined with balloon-guide catheters (BGC). Methods: Patients undergoing thrombectomy for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics. Clinical endpoint was the modified Rankin score (mRS) at 90-days, and technical outcomes were procedure time, total attempts, and mTICI scores. Results: The study included 2,016 patients (mean age 69±15) who underwent stroke thrombectomy using ADAPT (46%), SRT (46%), or SRT+BGC (8%). Similar baseline characteristics were observed between the three groups, and no significant difference in mRS scores at 90-days between the three groups in univariate and multivariate analyses. Thrombectomy performed using SRT+BGC required significantly shorter procedure time compared to SRT (35 vs 61 min, p0.1). However, use of SRT+BGC required significantly lower number of aspiration attempts compared to ADAPT (median 1 vs. 2, p Conclusions: This study shows that although ADAPT allows for faster procedure time compared to SRT, the use of BGC in SRT allows for a comparable procedure time to ADAPT with similar overall rates of favorable outcome, complications and hemorrhage. Mortality was higher with the use of BGC compared to ADAPT.

Introduction: Radiological hemorrhagic transformation (rHT) and symptomatic intracranial hemorrhage (sICH) remain a major complication of mechanical thrombectomy (MT) in acute stroke. Our aim is to identify independent predictors of rHT and sICH. Methods: A retrospective multicenter international study across the US and Europe included 2499 patients, 18 years or older, who underwent EVT for acute stroke from 2015-2019. rHT is defined as any intracranial hemorrhage post MT and subgrouped per ECASS II as petechial (HI), parenchymal hematoma without (PH1) and with mass effect (PH2) and subarachnoid hemorrhage (SAH). sICH was defined as presence of PH2 or SAH. Functional outcomes were described using the 90-day modified Rankin score (mRS) as “good” 0-2 or “poor” 3-6. Multivariable logistic regression model was used to identify predictors of rHT and sICH. Results: 600 (24%) had rHT and 145 (5.8%) had sICH. On multivariable regression model, independent predictors for both rHT and sICH were higher admission NIHSS (OR 1.03, p Conclusion: Compared to posterior circulation, anterior circulation strokes have higher rates of rHT and sICH. Baseline hyperlipidemia is protective for rHT or sICH post MT and this association needs further study. Clinical severity of stroke, poor ASPECTS on admission and higher thrombectomy attempts are associated with higher rates of rHT or sICH. Both rHT and sICH are independently associated with poor functional outcomes.

Introduction: Elderly patients, octogenarians and nonagenarians, were excluded or under-represented in the majority of stroke endovascular thrombectomy (ET) trials. There is conflicting data on the outcomes of ET in the elderly. We evaluated age-dependent outcomes of ET for stroke in a large dataset from the Stroke Thrombectomy and Aneurysm Registry (STAR). Methods: Patients undergoing ET for acute ischemic stroke at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Data was collected retrospectively from patient charts, procedure notes, and patient follow-up in neurology clinics. The primary endpoint was the modified Rankin score (mRS) at 90-days which was dichotomized into good outcome (mRS 0-2) or poor outcome (mRS 3-6). Results: Of 3,850 patients reviewed, 2,827 had 90-day follow-up (mean age 69±14), and were divided into 6 age groups: 20-49 (G1, 10%), 50-59 (G2, 10%), 60-69 (G3, 23%), 70-79 (G4, 27%), 80-89 (G5, 21%), 90 or more (G6, 4%). When adjusted for confounding variables, age was an independent predictor of poor outcome (OR=1.4, p Conclusions: Age is a major predictor of functional recovery after ET, and this study demonstrates a clear age-dependent increase in rate of mortality and poor outcomes after ET with exponentially worse outcomes above 80 years of age. Complication rates were not age-dependent. Further studies are required to optimize patient selection for ET in the elderly.

Introduction: Mechanical thrombectomy for acute ischemic stroke (AIS) is the current standard of care based on level 1 evidence from multiple randomized controlled trials. Recently, real-world indications for mechanical thrombectomy (MT) has extended beyond the inclusion criteria used in the majority of trials including elderly patients. We have recently developed a machine-learning based tool, SPOT, to optimize selection of elderly patients for MT based on single-center data. Here, we use a large cohort of international multicenter patients who underwent MT for AIS to externally validate SPOT. Methods: Patients who underwent MT for AIS at 12 comprehensive stroke centers in the US and Europe between 01/2013 and 12/2018 were reviewed. Patients age 80 years or older were included for validation of SPOT. SPOT is designed based on a combination of decision trees and linear regression models to provide binary output of predicted good (mRS 0-2) or poor outcome (mRS 3-6) after MT. SPOT uses admission variables: age, gender, comorbidities, admission NIHSS, baseline mRS score, ASPECT score and whether IV-tPA was administered. Predicted outcome was compared to actual outcome recorded at 90-days after treatment. A receiver operating characteristic curve was used to evaluate the accuracy of SPOT, and the negative predictive value was computed. The rate of post-procedural hemorrhage and mortality were compared between patients predicted by SPOT to have good versus poor outcome. Results: A total of 3,228 patients underwent MT for AIS during the study duration, of which 647 patients were at least 80 years of age or older and were included in the study. The average age was 85±5 years, and 65% were females. The median mRS score at 90 days was 4, and 21.3% had a good outcome (mRS 0-2). Of patients predicted by SPOT to have a poor outcome, 90% had a poor outcome. The area under the ROC curve was 0.7. The mortality rate in patients predicted by SPOT to have poor outcome had twice higher mortality than those predicted to have good outcome (55% vs 27%, p Conclusions: Based on multicenter validation, SPOT presents a clinical decision in aid in assisting for exclusion of elderly patients unlikely to benefit from MT for AIS with a 90% negative predictive value.

BackgroundAtrial fibrillation (AF) associated ischemic stroke has worse functional outcomes, less effective recanalization, and increased rates of hemorrhagic complications after intravenous thrombolysis (IVT). Limited data exist about the effect of AF on procedural and clinical outcomes after mechanical thrombectomy (MT).ObjectiveTo determine whether recanalization efficacy, procedural speed, and clinical outcomes differ in AF associated stroke treated with MT.MethodsWe performed a retrospective cohort study of the Stroke Thrombectomy and Aneurysm Registry (STAR) from January 2015 to December 2018 and identified 4169 patients who underwent MT for an anterior circulation stroke, 1517 (36.4 %) of whom had comorbid AF. Prospectively defined baseline characteristics, procedural outcomes, and clinical outcomes were reported and compared.ResultsAF predicted faster procedural times, fewer passes, and higher rates of first pass success on multivariate analysis (pConclusionsIn patients treated with MT, comorbid AF is associated with faster procedural time, fewer passes, and increased rates of first pass success without increased risk of intracranial hemorrhage or worse functional outcomes. These results are in contrast to the increased hemorrhage rates and worse functional outcomes observed in AF associated stroke treated with supportive care and or IVT. These data suggest that MT negates the AF penalty in ischemic stroke.