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Endovascular treatment of cervical internal carotid artery (ICA) loop dissections in acute stroke interventions can be challenging. Flow diverters can effectively reconstruct vessel loops and treat the injured vessel and provide a safe conduit for intracranial catheterization.We retrospectively reviewed our neurointerventional database and identified all patients with ICA loop dissections treated with flow diverters in the acute setting between August 2016 and September 2020. Patient demographics, procedural data, imaging follow-up results, and clinical outcome information were collected.Seven patients with a mean age of 62 years (range: 43-85 years) who underwent reconstruction of an ICA (loop) dissection with flow diverters were included. Four ICA dissections were treated with the Surpass Streamline flow diverter and 3 with the Pipeline embolization device. All cases were technically successful. All stroke cases achieved intracranial flow ≥thrombolysis in cerebral infarction 2B. Observed intracranial hemorrhages were all asymptomatic. All cases showed patent flow diverter(s) with or without (carotid) stent(s) on follow-up imaging. Semielectively treated patients did not show a change from baseline modified Rankin scale related to the procedure. Patients with acute stroke had a modified Rankin scale ≤2 in 4 of 5 cases (80%) at 3 months. Two patients died due to medical issues unrelated to the procedures. No patient showed new or recurrent symptoms.Use of flow diverters, in some cases in conjunction with (carotid) stents, is an effective treatment option for cervical carotid artery (loop) dissections.

We describe a novel technique of vein of Labbé preservation using balloon protection during embolisation of a transverse-sigmoid sinus dural arteriovenous fistula. A patient with refractory Cognard type IV fistula of the left transverse-sigmoid sinus and persistent pulsatile tinnitus underwent successful embolisation of the lesion via transarterial route. During embolisation, a dual lumen balloon was simultaneously inflated within the vein of Labbé, at its orifice in the transverse-sigmoid sinus junction, to prevent embolic reflux. This allowed for liquid embolic embolisation of the fistula via the transarterial route resulting in complete occlusion. The patient recovered well with marked improvement of his tinnitus.

BackgroundData regarding the safety and efficacy of flow diverting stents (FDS) in the treatment of middle cerebral artery (MCA) bifurcation aneurysms are scarce and limited to small single center series, with particular concern for increased risk of ischemic complications with jailing one of the M2 branches.MethodsProspectively-maintained databases at six North American and European centers were queried for patients harboring MCA bifurcation aneurysms undergoing treatment with FDS (2011–2018). The pertinent clinical and radiographic data were collected and analyzed.Results87 patients (median age 60 years, 69% females) harboring 87 aneurysms were included. The majority of aneurysms were unruptured (79%); 75.9% were saccular with a median maximal diameter of 8.5 mm. Radiographic imaging follow-up was available in 88.5% of cases at a median of 16.3 months post-treatment, showing complete occlusion in 59% and near complete occlusion (90–99%) in 18% of aneurysms. The overall rate of ischemic and hemorrhagic complications was 8% and 1.1%, respectively. Symptomatic and permanent complications were encountered in 5.7% and 2.3% of patients respectively, with retreatment pursued in 2.3% of patients. Jailed branch occlusion was detected in 11.5% of cases, with clinical sequelae in 2.3%. Last follow-up modified Rankin Scale of 0–2 was noted in 96.8% of patients. On multivariate analysis, male sex was the only independent predictor of aneurysmal persistence at last follow-up imaging (p=0.019).ConclusionFDS treatment for MCA bifurcation aneurysms is feasible, with comparable safety and efficacy profiles to other available endovascular options when utilized in carefully selected aneurysms. Jailing of M2 branches was not associated with a higher risk of post-procedural ischemic complications.

IntroductionThe Walrus balloon guide catheter (BGC) is a new generation of BGC, designed to eliminate conventional limitations during mechanical thrombectomy.ObjectiveTo report a multi-institutional experience using this BGC for proximal flow control (PFC) in the setting of carotid artery angioplasty/stenting (CAS) in elective (eCAS) and tandem strokes (tCAS).MethodsProspectively maintained databases at 8 North American centers were queried to identify patients with cervical carotid disease undergoing eCAS/tCAS with a Walrus BGC.Results110 patients (median age 68, 64.6% male), 80 (72.7%) undergoing eCAS and 30 (27.3%) tCAS procedures, were included (median cervical carotid stenosis 90%; 46 (41.8%) with contralateral stenosis). Using a proximal flow-arrest technique in 95 (87.2%) and flow-reversal in 14 (12.8%) procedures, the Walrus was navigated into the common carotid artery successfully in all cases despite challenging arch anatomy (31, 28.2%), with preferred femoral access (103, 93.6%) and in monitored anesthesia care (90, 81.8%). Angioplasty and distal embolic protection devices (EPDs) were used in 91 (83.7%) and 58 (52.7%) procedures, respectively. tCAS led to a modified Thrombolysis in Cerebral Infarction 2b/3 in all cases. Periprocedural ischemic stroke (up to 30 days postoperatively) rate was 0.9% (n=1) and remote complications occurred in 2 (1.8%) cases. Last follow-up modified Rankin Scale score of 0–2 was seen in 95.3% of eCAS cohort, with no differences in complications in the eCAS subgroup between PFC only versus PFC and distal EPD (median follow-up 4.1 months).ConclusionWalrus BGC for proximal flow control is safe and effective during eCAS and tCAS. Procedural success was achieved in all cases, with favorable safety and functional outcomes on short-term follow-up.

BACKGROUND AND PURPOSE: Transradial access for neurointerventional procedures has been proved a safer and more comfortable alternative to femoral artery access. We present our experience with transradial (distal radial/anatomic snuffbox and radial artery) access for treatment of intracranial aneurysms using all 3 FDA-approved flow diverters. MATERIALS AND METHODS: This was a high-volume, dual-center, retrospective analysis of each institution’s data base between June 2018 and June 2020 and a collection of all patients treated with flow diversion via transradial access. Patient demographic information and procedural and radiographic data were obtained. RESULTS: Seventy-four patients were identified (64 female patients) with a mean age of 57.5 years with a total of 86 aneurysms. Most aneurysms were located in the anterior circulation (93%) and within the intracranial ICA (67.4%). The mean aneurysm size was 5.5 mm. Flow diverters placed included the Pipeline Embolization Device (Flex) (PED, n = 65), the Surpass Streamline Flow Diverter (n = 8), and the Flow-Redirection Endoluminal Device (FRED, n = 1). Transradial access was successful in all cases, but femoral crossover was required in 3 cases (4.1%) due to tortuous anatomy and inadequate support of the catheters in 2 cases and an inability to navigate to the target vessel in a patient with an aberrant right subclavian artery. All 71 other interventions were successfully performed via the transradial approach (95.9%). No access site complications were encountered. Asymptomatic radial artery occlusion was encountered in 1 case (3.7%). CONCLUSIONS: Flow diverters can be successfully placed via the transradial approach with high technical success, low access site complications, and a low femoral crossover rate.

Background Intracranial dural arteriovenous fistulae (dAVFs) with cortical venous drainage (CVD) require treatment because of their aggressive clinical presentation and natural history. Although endovascular treatment is effective for the majority of these lesions in the current endovascular era, surgical management has been required if the lesions are not amenable to or fail endovascular treatments. Objective To demonstrate the angioarchitecture that may necessitate surgical intervention. Methods A retrospective review of the patients with intracranial dAVFs with CVD treated at 2 academic institutions between January 1, 2009, and July 31, 2019 was performed. Patients who required surgical intervention were selected in this study, and angiographic findings were analyzed. Results A total of 81 dAVFs in 80 patients were treated during the study period. Endovascular treatments were attempted for 72 (88.9%) dAVFs, resulting in complete obliteration in 55 (76.4%). Surgical interventions were performed in 18 (22.2%) dAVFs, resulting in complete obliteration in all lesions. Overall, complete obliteration was achieved in 74 (93.7%) of 79 dAVFs with follow-up. In the surgically treated dAVFs, curative transarterial embolization was deterred by the angioarchitecture, which included dominant feeding vessels from the ophthalmic artery, meningohypophyseal trunk, posterior meningeal artery, pial artery, or ascending pharyngeal artery. Drainage through tortuous cortical vein, deep venous system, or isolated sinus made transvenous approach challenging. Conclusion Despite continued improvement in endovascular technology, surgical approaches to dAVFs are still of great value as initial and salvage treatment of dAVFs with angioarchitecture hampering endovascular treatment.

Preliminary experience with distal radial artery (dRA) access for diagnostic cerebral angiography and some neurointerventional procedures has proved to be promising with good technical results and a reliable safety profile. Vascular access via the dRA may further improve minimally invasive treatment of intracranial aneurysms. Between July 2019 and June 2020 we identified 11 patients (9 females) with a mean age of 63.5 years who underwent WEB device placement for treatment of their intracranial aneurysm via the dRA approach. The mean aneurysm size (largest diameter) was 6.7 mm. One patient required conversion to femoral access due to severe brachial artery fibromuscular dysplasia. Placement of the WEB device was successful in all other cases via dRA approach. In all but one case, a low profile triaxial catheter system with the 6F Benchmark guide catheter (Penumbra) and 5F Sofia distal access catheter (Microvention) were used. No access related complications were observed. The combination of the intrasaccular WEB device and dRA access represents an ideal approach which offers operators a low risk vascular access and high procedural success by maintaining the ability to precisely place and manipulate the device using low-profile catheter systems. At the same time, this approach offers patients the most minimally invasive experience currently available for treatment of intracranial aneurysms with quick postprocedural recovery, minimal restrictions and low risk for access site complications.

Purpose To report use of distal radial artery (dRA) access for carotid artery stenting (CAS) and to discuss procedural setup and technical considerations for a successful intervention. Methods A retrospective review of our prospective neurointerventional database of CAS was conducted between May 2019 and March 2020. All CAS cases via dRA in the anatomical snuffbox were identified. Patient demographics, clinical information, procedural and radiographic data was collected. Results 22 CAS procedures in 20 patients via dRA were identified. Patients’ mean age was 69.4 years (range 53–87 years). 3 patients were female. Mean radial artery diameter was 2.1 mm (range 1.6–2.8 mm). dRA access was achieved in all cases. Conversion to femoral access was required in 2 cases (9.1%) due to persistent radial artery vasospasm resulting in patient discomfort despite multiple additional doses of intraarterial vasodilators and added intravenous sedation as well as tortuous vessel anatomy and limited support of the catheters in a type 3 aortic arch for left CAS. Conclusion Our preliminary experience with dRA access for CAS suggests this approach to be feasible and safe for patients. Technical considerations are important and preprocedural planning is necessary for a successful intervention. Catheter systems and devices specifically designed for radial access are needed to enable more interventionalists to safely perform neurointerventional procedures via wrist access.

Partially thrombosed intracranial aneurysms (PTIA) represent a unique subset of intracranial aneurysms with an ill-defined natural history, posing challenges to standard management strategies. This study aims to assess the efficacy of flow diversion in the treatment of this pathology.A retrospective review of patients with flow-diverted PTIA at 6 cerebrovascular centers was performed. Clinical and radiographic data were collected from the medical records, with the primary outcome of aneurysmal occlusion and secondary outcomes of clinical status and complications.Fifty patients with 51 PTIA treated with flow diversion were included. Median age was 56.5 years. Thirty-three (64.7%) aneurysms were saccular and 16 (31.4%) were fusiform/dolichoectatic. The most common location was the internal carotid artery (54.9%) followed by the vertebral and basilar arteries (17.7% and 17.7%, respectively). Last imaging follow-up was performed at a median of 25.1 (interquartile range, 12.8-43) months. Complete occlusion at last radiographic follow-up was achieved in 37 (77.1%) aneurysms. Pretreatment aneurysm thrombosis of50% was associated with a significantly lower rate of complete aneurysm occlusion (58.8 vs. 87.1%, P = 0.026) with a trend toward better functional outcome (modified Rankin scale2) at last follow-up in patients with50% pretreatment aneurysm thrombosis (96.8 vs. 82.4; P = 0.08). Ischemic complications occurred in 5 (9.8%) patients, producing symptoms in 4 (7.8%) and resultant mortality in 2 (4.2%) patients.Flow diversion treatment of PTIA has adequate efficacy along with a reasonable safety profile. Aneurysms harboring large amounts of pretreatment thrombus were associated with lower rates of complete occlusion.

Background Neurointerventionalists use in-vitro vascular models to train for worst-case scenarios and test new devices in a simulated use environment to predict clinical performance. According to the Food and Drug Administration (FDA), any neurovascular navigation device should be able to successfully navigate two 360-degree turns and two 180-degree turns at the distal portion of the anatomical model. Here, we present a device benchmarking vascular model that complies with FDA recommendations. Methods Our vascular model was assembled from quantitative characterization of 49 patients who underwent CT angiography either for acute ischemic stroke caused by large vessel occlusion or for aneurysm treatment. Following complete characterization of these data, the vascular segments were 3D reconstructed from CT angiograms of 6 selected patients that presented with challenging anatomy. The curvature and total rotational angle were calculated for each segment and the anatomical parts that complied with FDA recommendations were fused together into a single in-vitro model. Results The model was constructed containing two common carotid branches arising from a type two aortic arch and the dimensions of the overall model exceeded the recommendations of the FDA. Two experienced neurointerventionalists tested the model for navigation difficulty using several devices on an in-vitro perfusion system and concluded that the model provided a realistic, challenging scenario. Conclusions This model provides a first prototype designed according to FDA recommendations of cumulative angle while also integrating an aggregation of actual patient-specific anatomy. The availability of this clinically relevant benchmark model presents a potential standardized approach for neurovascular device testing.

BackgroundTo analyse the clinical characteristics of COVID-19 with acute ischaemic stroke (AIS) and identify factors predicting functional outcome.MethodsMulticentre retrospective cohort study of COVID-19 patients with AIS who presented to 30 stroke centres in the USA and Canada between 14 March and 30 August 2020. The primary endpoint was poor functional outcome, defined as a modified Rankin Scale (mRS) of 5 or 6 at discharge. Secondary endpoints include favourable outcome (mRS ≤2) and mortality at discharge, ordinal mRS (shift analysis), symptomatic intracranial haemorrhage (sICH) and occurrence of in-hospital complications.ResultsA total of 216 COVID-19 patients with AIS were included. 68.1% (147/216) were older than 60 years, while 31.9% (69/216) were younger. Median [IQR] National Institutes of Health Stroke Scale (NIHSS) at presentation was 12.5 (15.8), and 44.2% (87/197) presented with large vessel occlusion (LVO). Approximately 51.3% (98/191) of the patients had poor outcomes with an observed mortality rate of 39.1% (81/207). Age >60 years (aOR: 5.11, 95% CI 2.08 to 12.56, pConclusionThere is relationship between COVID-19-associated AIS and severe disability or death. We identified several factors which predict worse outcomes, and these outcomes were more frequent compared to global averages. We found that elevated neutrophil-to-lymphocyte ratio, rather than D-Dimer, predicted both morbidity and mortality.

Key Points Question In patients with proximal anterior circulation occlusion stroke presenting in the extended window, are rates of favorable outcomes at 90 days comparable in the patients selected for thrombectomy with noncontrast computed tomography vs patients selected with computed tomography perfusion or magnetic resonance imaging? Findings In a multicenter cohort of 1604 patients in the extended window with large-vessel occlusion, patients selected by noncontrast computed tomography had comparable clinical and safety outcomes with patients selected by computed tomography perfusion or magnetic resonance imaging. Meaning These findings suggest noncontrast computed tomography alone may be used as an alternative to advanced imaging in selecting patients with late-presenting large-vessel occlusion for mechanical thrombectomy., This cohort study compares the clinical outcomes of patients with stroke who presented 6 to 24 hours after symptom onset and were selected for mechanical thrombectomy by noncontrast computed tomography vs those selected by computed tomography perfusion or magnetic resonance imaging., Importance Advanced imaging for patient selection in mechanical thrombectomy is not widely available. Objective To compare the clinical outcomes of patients selected for mechanical thrombectomy by noncontrast computed tomography (CT) vs those selected by computed tomography perfusion (CTP) or magnetic resonance imaging (MRI) in the extended time window. Design, Setting, and Participants This multinational cohort study included consecutive patients with proximal anterior circulation occlusion stroke presenting within 6 to 24 hours of time last seen well from January 2014 to December 2020. This study was conducted at 15 sites across 5 countries in Europe and North America. The duration of follow-up was 90 days from stroke onset. Exposures Computed tomography with Alberta Stroke Program Early CT Score, CTP, or MRI. Main Outcomes and Measures The primary end point was the distribution of modified Rankin Scale (mRS) scores at 90 days (ordinal shift). Secondary outcomes included the rates of 90-day functional independence (mRS scores of 0-2), symptomatic intracranial hemorrhage, and 90-day mortality. Results Of 2304 patients screened for eligibility, 1604 patients were included, with a median (IQR) age of 70 (59-80) years; 848 (52.9%) were women. A total of 534 patients were selected to undergo mechanical thrombectomy by CT, 752 by CTP, and 318 by MRI. After adjustment of confounders, there was no difference in 90-day ordinal mRS shift between patients selected by CT vs CTP (adjusted odds ratio [aOR], 0.95 [95% CI, 0.77-1.17]; P = .64) or CT vs MRI (aOR, 0.95 [95% CI, 0.8-1.13]; P = .55). The rates of 90-day functional independence (mRS scores 0-2 vs 3-6) were similar between patients selected by CT vs CTP (aOR, 0.90 [95% CI, 0.7-1.16]; P = .42) but lower in patients selected by MRI than CT (aOR, 0.79 [95% CI, 0.64-0.98]; P = .03). Successful reperfusion was more common in the CT and CTP groups compared with the MRI group (474 [88.9%] and 670 [89.5%] vs 250 [78.9%]; P

Background: Aneurysmal persistence after flow diversion (FD) occurs in 5% to 25% of aneurysms, which may necessitate retreatment. There are limited data on safety/efficacy of repeat FD—a frequently utilized strategy in such cases. Methods: A series of consecutive patients undergoing FD retreatment from 15 centers were reviewed (2011–2019), with inclusion criteria of repeat FD for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months post-retreatment imaging. The primary outcome was aneurysmal occlusion, and secondary outcome was safety. A multivariable logistic regression model was constructed to identify predictors of incomplete occlusion (90%–99% and Results: Ninety-five patients (median age, 57 years; 81% women) harboring 95 aneurysms underwent 198 treatment procedures. Majority of aneurysms were unruptured (87.4%), saccular (74.7%), and located in the internal carotid artery (79%; median size, 9 mm). Median elapsed time between the first and second treatment was 12.2 months. Last available follow-up was at median 12.8 months after retreatment, and median 30.6 months after the initial treatment, showing complete occlusion in 46.2% and near-complete occlusion (90%–99%) in 20.4% of aneurysms. There was no difference in ischemic complications following initial treatment and retreatment (4.2% versus 4.2%; P >0.99). On multivariable regression, fusiform morphology had higher nonocclusion odds after retreatment (odds ratio [OR], 7.2 [95% CI, 1.97–20.8]). Family history of aneurysms was associated with lower odds of nonocclusion (OR, 0.18 [95% CI, 0.04–0.78]). Likewise, positive smoking history was associated with lower odds of nonocclusion (OR, 0.29 [95% CI, 0.1–0.86]). History of hypertension trended toward incomplete occlusion (OR, 3.10 [95% CI, 0.98–6.3]), similar to incorporated branch into aneurysms (OR, 2.78 [95% CI, 0.98–6.8]). Conclusions: Repeat FD for persistent aneurysms carries a reasonable success/safety profile. Satisfactory occlusion (100% and 90%–99% occlusion) was encountered in two-thirds of patients, with similar complications between the initial and subsequent retreatments. Fusiform morphology was the strongest predictor of retreatment failure.

Basilar artery perforator aneurysms are very rare and usually present with subarachnoid hemorrhage. High-quality imaging systems with digital subtraction angiography and three-dimensional rotational angiography are crucial for the detection of these posterior circulation vascular lesions, which may still be missed on the initial angiogram. We present the first use of a Flow Re-Direction Endoluminal Device (Microvention, Aliso Viejo, California) for treatment of a ruptured basilar artery perforator aneurysm via snuffbox vascular access and use of cangrelor for antiplatelet management.

Background Parent vessel sacrifice (PVS) has been a traditional way of treating complex aneurysms of the intradural vertebral artery (VA). Flow diversion (FD) has emerged as an alternative reconstructive option. Objective To compare the long-term clinical and radiographic outcomes of intradural VA aneurysms following PVS or FD. Methods We retrospectively reviewed and evaluated 43 consecutive patients between 2009 and 2018 with ruptured and unruptured intradural VA aneurysms treated by PVS or FD. Medical records including clinical and radiological details were reviewed. Results A total of 43 intradural VA aneurysms were treated during this period. In the 14 PVS patients, the mean follow-up was 19.5 mo, and 71.4% of cases achieved modified Rankin scale (mRS) ≤2 at the last follow-up. A total of 86.5% of cases achieved complete occlusion. There was a 14.3% (2 cases) mortality rate, 14.3% (2 cases) postoperative ischemic complication rate, and 0% postoperative hemorrhaging rate. Retreatment was required in 1 case (7.1%). In the 29 FD patients, the mean follow-up was 21.8 mo, and 89.7% of cases achieved mRS ≤2 at the final follow-up. There was a 3.2% (1 case) mortality rate, 19.4% (6 cases) of postoperative ischemic complications, and 6.5% (2 cases) of postoperative hemorrhagic complications. Complete occlusion was seen in 86.5% patients. No cases required retreatment. Mortality and complication rates were not significantly different between PVS and PED (Pipeline Embolization Device) groups. Conclusion PVS was associated with comparable intraprocedural complications for VA aneurysms as compared to FD in the largest multicenter study to date. Both procedures have good long-term clinical and radiological outcomes.

OBJECTIVEWith the increasing use of flow diversion as treatment for intracranial aneurysms, there is a concomitant increased vigilance in monitoring complications. The low porosity of flow diverters is concerning when the origins of vessels are covered, whether large circle of Willis branches or critical perforators. In this study, the authors report their experience with flow diverter coverage of the lenticulostriate vessels and evaluate their safety and outcomes.METHODSThe authors retrospectively reviewed 5 institutional databases of all flow diversion cases from August 2012 to June 2018. Information regarding patient presentation, aneurysm location, treatment, and outcomes were recorded. Patients who were treated with flow diverters placed in the proximal middle cerebral artery (MCA), proximal anterior cerebral artery, or distal internal carotid artery leading to coverage of the medial and lateral lenticulostriate vessels were included. Clinical outcomes according to the modified Rankin Scale were reviewed. Univariate and multivariate analyses were performed to establish risk factors for lenticulostriate infarct.RESULTSFifty-two patients were included in the analysis. Postprocedure cross-sectional images were available in 30 patients. Two patients experienced transient occlusion of the MCA during the procedure; one was asymptomatic, and the other had a clinical and radiographic ipsilateral internal capsule stroke. Five patients had transient symptoms without radiographic infarct in the lenticulostriate territory. Two patients experienced in-stent thrombosis, leading to clinical MCA infarcts (one in the ipsilateral caudate) after discontinuing antiplatelet therapy. Discontinuation of dual antiplatelet therapy prior to 6 months was the only variable that was significantly correlated with stroke outcome (p < 0.01, OR 0.3, 95% CI 0–0.43), and this significance persisted when controlled for other risk factors, including age, smoking status, and aneurysm location.CONCLUSIONSThe use and versatility of flow diversion is increasing, and safety data are continuing to accumulate. Here, the authors provide early data on the safety of covering lenticulostriate vessels with flow diverters. The authors concluded that the coverage of these perforators does not routinely lead to clinically significant ischemia when dual antiplatelet therapy is continued for 6 months. Further evaluation is needed in larger cohorts and with imaging follow-up as experience develops in using these devices in more distal circulation.

PurposeTo report the first use of distal radial artery (dRA) access for a variety of neurointerventions and to demonstrate the safety and feasibility of this approach.MethodsA retrospective review of our prospective neurointerventional database of endovascular interventions was conducted and, between May and October 2019, all patients in whom the intervention was performed via dRA in the anatomical snuffbox were identified. Patient demographics, clinical information, procedural and radiographic data were collected.Results48 patients with a mean age of 64.4 years (range 35–84 years) were included. 27 patients were female. dRA access was achieved in all cases. Conversion to femoral access was required in five cases (10.4%) due to tortuous vessel anatomy and limited support of the catheters in the aortic arch. Interventions performed included aneurysm treatment (with flow diverters, Woven EndoBridge device placement, coiling or stent-assisted coiling), arteriovenous malformation and dural arteriovenous fistula embolization, carotid artery stentings, stroke thrombectomy, thrombolysis for central retinal artery occlusion, intracranial stenting, middle meningeal artery embolization, vasospasm treatment, and spinal angiography with embolization. Radial artery vasospasm was seen in two cases and successfully treated with antispasmolytic medication. No symptomatic radial artery occlusion or ischemic event was observed.ConclusiondRA access is safe and effective for a variety of neurointerventions. Our preliminary experience with this approach is very promising and shows high patient satisfaction.

The introduction of flow diverter technology to the field of neurointervention has revolutionized the treatment of intracranial aneurysms. The therapy approach has shifted from intrasaccular aneurysm treatment to exclusion of the aneurysm from the blood circulation with remodeling of the parent artery. Previously, "difficult"-to-treat aneurysms including fusiform and blister aneurysms, but also aneurysms arising from a diseased vessel segment, can now be safely and permanently treated with flow diverters. A little over a decade ago, after extensive bench testing and refinement of the flow diverter concept, the device was eventually available for clinical use and today it has become a standard treatment for intracranial aneurysms. Currently, United States Food and Drug Administration (FDA)-approved flow diverters are the Pipeline Embolization Device (Medtronic) and the Surpass Streamline Flow Diverter (Stryker). The devices can either be delivered or deployed via a standard femoral artery approach or a radial artery approach. Other considerations for catheter setup and device deployment strategies depending on aneurysm location or vessel anatomy are described.

Severe hypertension is a major cause, among a long list of recognized causative factors of posterior reversible encephalopathy (PRES). We present an interesting case of a middle-aged patient with hypertension and asymmetric distribution of PRES due to tumor-related encasement and narrowing of the right internal carotid artery and relative sparing of the ipsilateral right cerebral hemisphere. White matter lesions from PRES were mostly seen in the contralateral left cerebral hemisphere and bilateral posterior fossa. It is theorized that organs or tissues distal to a chronically constricted vessel are protected from hypertensive changes (such as PRES) as the arterial stenosis reduces the transmission of hypertension-related effects, presumably due to a combination of hypoperfusion and alterations in compensatory changes in vessel autoregulation. While protected from the effects of hypertension, the patient is, however, at risk for border-zone infarction from hypoperfusion.We believe that this case report provides a better understanding of the mechanism underlying the etiology of PRES as primarily regulated by the important baroreceptors and autoregulation mechanism of the carotid artery. Keywords: Headache, Hypertension, Posterior reversible encephalopathy syndrome, PRES, Vessel stenosis, White matter

The purpose of this study was to evaluate safety and efficacy of the pipeline embolization device (PED) in different patient age groups with unruptured intracranial aneurysms (UIA). All patients with UIA treated with the PED between 2011 and 2017 were included. Based on their age, patients were trichotomized to: young (≤45 years), middle-aged (46 to65 years) and older (≥65 years) groups. Patient's vascular risk factors, presenting symptoms and mRS on admission were collected. Follow-up imaging was evaluated for presence/absence of aneurysm occlusion. Clinical outcome at discharge, 3-9 months and 12-18 months was also documented when available. A total of 260 patients harboring 307 aneurysms (young = 57, middle-age = 144 and older age group = 64). Most aneurysms were located in the anterior circulation (94.8%). Overall morbidity and mortality was 2.3% each (6/260). At 3-9 months near complete to complete aneurysm occlusion was 82.5% (47/57) in the young age group, 82.6% (100/121) in the middle age, and 70.2% (40/57) in the older age group. At 12-18-month, near complete to complete occlusion was 100% in the young age group (32/32), 91.4% (64/70) in the middle age, and 78.4% (29/37) in the older age group. After adjustment for potential confounders, older age patients less frequently achieved near complete to complete occlusion by 3 years than younger subjects (p = 0.009, HR 1.34 95%, CI 1.08-1.66). Our results indicate feasibility and safety of PED across different age groups. Further study is required to determine age-related factors relating to aneurysm occlusion after PED to improve outcome and patient counseling.

Purpose To evaluate the effectiveness and safety of image-guided percutaneous bleomycin sclerotherapy as a minimally invasive treatment approach for craniofacial (veno)lymphatic malformations in children and adolescents. Material and Methods We retrospectively reviewed our prospectively maintained Neuro IR database between January 2018 and June 2020 and identified all children and adolescents (1 to 19 years) who underwent percutaneous fluoroscopy guided bleomycin sclerotherapy for craniofacial (veno)lymphatic malformations. Patient clinical and imaging follow up data was collected. Results We identified 4 patients (2 female patients) between 20 months and 12 years old who presented with clinical and radiographic craniofacial (veno)lymphatic malformations. Two lesions were macrocystic, 1 microcystic and 1 mixed. No procedural complications ensued. On first follow up examination 2 patients report obvious decrease in size of the malformation which is confirmed with ultrasound and/or visual inspection. One patient subjectively reported minimal decrease in size with the ultrasound evaluation not showing any change from prior to the procedure. One patient who showed initial decrease in size of the lesion already underwent a second sclerotherapy session and is awaiting his next follow up appointment. The other 2 patients are scheduled to undergo their next sclerotherapy session as well. One patient did not reach the first follow up time point yet. Conclusion Sclerotherapy should be considered in selected patients with craniofacial (veno)lymphatic malformations as it represents a safe and successful treatment option, especially if surgical excision is considered challenging, with a high risk of complication and postoperative recurrence. Patients and parents have to be aware that sclerotherapy may require several sessions to achieve results. Generally, patients and parents are satisfied with sclerotherapy treatment outcomes, specifically the cosmetic results. Disclosures A. Kuhn: None. A. Puri: 1; C; NIH, Stryker Neurovascular, Medtronic, Cerenovus. 2; C; Microvention, QApel, Perfuze Medical, Arsenal Medical, Merit Medical, Stryker Neurovascular, Medtronic, Cerenovus. 4; C; InNeuroCo Inc, Galaxy therapeutics, Agile Medical, Perfuze medical and NTI. C. Zoppo: None. K. de Macedo Rodrigues: None. F. Massari: None. M. Gounis: 1; C; National Institutes of Health (NIH), the United States – Israel Binational Science Foundation, Anaconda, ApicBio, Axovant, Cerenovus, Cook Medical, Gentuity, Imperative Care, InNeuroCo, Magneto. 2; C; Cerenovus, Imperative Care, phenox, Medtronic Neurovascular, Route 92 Medical, Stryker Neurovascular. 4; C; Imperative Care, InNeuroCo and Neurogami. J. Singh: None.

Purpose To report the feasibility and safety of anatomical snuffbox access (distal radial artery, dRA) for carotid artery stenting (CAS). Methods We performed a retrospective review of our prospectively maintained neurointerventional database of CAS cases between May 2019 and February 2021. All CAS cases via the anatomical snuffbox were identified. Patient demographics, clinical information, procedural and radiographic data was collected. Results 24 CAS procedures in 22 patients via the anatomical snuffbox were identified. Patients‘ mean age was 69.5 years (range 53-87 years). 4 patients were female. Mean radial artery diameter was 2.1 mm (range 1.6-2.8 mm). Snuffbox access was achieved in all cases. Sixteen procedures involved the right carotid artery. In 19 cases a Carotid Wallstent (Boston Scientific) was used. In 2 cases a Viabahn stent graft (Gore) was placed and a Precise stent (Cordis) was deployed in 1 case. Conversion to femoral access was required in 2 cases (8.3%) due to persistent radial artery vasospasm resulting in patient discomfort despite multiple additional doses of intraarterial vasodilators and added intravenous sedation as well as tortuous vessel anatomy and limited support of the catheters in a type 3 aortic arch for left CAS. In our cases, dRA access was mainly obtained with a 6F Prelude Ideal hydrophilic sheath introducer (Merit Medical) and procedures were mainly performed using a Benchmark catheter (Penumbra). In 3 cases a Fubuki guide catheter (Asahi Intecc) was directly inserted into the dRA over the exchange length wire (sheath-less or bareback catheter use) after removal of the sheath. In one case, a 6F Benchmark guide catheter was used to gain direct access to the dRA. We did not observe any peri- or postprocedural access site complications. No access site complications were noted. A cerebral protection device was used in all cases. There was no morbidity or mortality associated with any of the CAS interventions. Conclusion Our preliminary experience with anatomical snuffbox access for CAS suggests this approach to be feasible and safe for patients. Preprocedural planning and technical considerations are both important for a successful procedure.Nevertheless, catheter systems and devices specifically designed for radial access are needed and will likely enable more interventionalists to safely perform such procedures via hand/wrist access. Disclosures A. Kuhn: None. J. Singh: None. S. Satti: 2; C; Balt, Stryker Neuromuscular, Cerenovus, Medtronic, Microvention, Terumo. T. Eden: None. V. Moholkar: None. K. de Macedo Rodrigues: None. F. Massari: None. V. Naragum: None. V. Anagnostakou: None. M. Gounis: 1; C; National Institutes of Health (NIH), the United States – Israel Binational Science Foundation, Anaconda, ApicBio, Axovant, Cerenovus, Cook Medical, Gentuity, Imperative Care, InNeuroCo, Magneto. 2; C; Cerenovus, Imperative Care, phenox, Medtronic Neurovascular, Route 92 Medical, Stryker Neurovascular. 4; C; Imperative Care, InNeuroCo and Neurogami. A. Puri: 1; C; NIH, Stryker Neurovascular, Medtronic, Cerenovus. 2; C; Microvention, QApel, Perfuze Medical, Arsenal Medical, Merit Medical, Stryker Neurovascular, Medtronic, Cerenovus. 4; C; InNeuroCo Inc, Galaxy therapeutics, Agile Medical, Perfuze medical and NTI.

Purpose To report the feasibility, safety and efficacy of the large bore catheters with matching Tenzing inserts for first pass efficacy in stroke thrombectomy without need for crossing the clot. Methods We performed a retrospective review of our prospectively maintained neurointerventional database of mechanical thrombectomy for stroke. Patient demographics, clinical information, procedural and radiographic data was collected. Results The most widely used techniques for stroke thrombectomy are aspiration, stent-retrievers or combination of these. The Mount Everest Technique (MET) has been designed combining innovative technology and the “Law of Conservation of Matter”, taking advantage of not needing to cross the clot with the bigger catheters to “ingest” the clot with very high first pass success. The Mount Everest Technique (MET) entails a triaxial assembly with an 8 Fr 0.106” Guiding Catheter (Base Camp), a 088” HiPoint “catheter on a stick/wire” with matching self-centering Tenzing insert catheter. The Tenzing catheter is used to climb up to the clot then, while pulling this insert out, the 088” catheter is capable to progress into the clot “ingesting” it, thanks to the “Law of Conservation of Matter”. The aspiration force is applied from the Base Camp catheter with the 088” HiPoint within the clot as a single assembly, thus taking the advantage of the super large bore distal catheter and the stable 0.106” Base Camp, resulting in the capability of physically “ingest” the clot. At the time of the abstract submission, we have utilized this novel Mount Everest Technique (MET) in 6 patients with large vessel occlusions involving the anterior circulation (ICA T-terminus and MCA M1 occlusions), with single pass (5) and 2 passes (1) complete vascular reperfusion of the occluded vessel in all the cases (TICI 3). No embolization in previously unaffected vascular territories or post procedure SAH has been observed. Conclusion The Mount Everest Technique (MET) combines the technological novelty of the 0.106” Base Camp, 088” HiPoint and matching self-centering Tenzing insert catheters to navigate these super large bore catheters to the face of the clot without needing to cross them with large microcatheters or wires. Thereafter based on the “Law of Conservation of Matter”, the retraction of the Tenzing insert while applying a suction force at the HiPoint catheter results in the “ingestion” of the clot in toto. This technique and catheter combination have led to 100% TICI 3 recanalization with 80% first pass success in our initial experience. Disclosures F. Massari: None. J. Singh: None. A. Kuhn: None. V. Naragum: None. V. Anagnostakou: None. M. Gounis: None. A. Puri: None.

BackgroundThe use of a balloon-guide catheter (BGC) in acute stroke treatment has been widely adopted after demonstrating optimized procedure metrics and outcomes. Initial technical constraints of previous devices included catheter stiffness and smaller inner diameters. We aim to evaluate the performance and safety of the Walrus BGC, a variable stiffness catheter with a large bore 0.087 inch inner diameter (ID), via the the WICkED study (Walrus Large Bore guide Catheter Impact on reCanalization first pass Effect anD outcomes).MethodsThis is a retrospective, site adjudicated, multicenter study on consecutive patients with large vessel occlusion treated with the Walrus BGC. Baseline characteristics, procedural outcomes and functional outcomes were analyzed.ResultsA total of 338 patients met the inclusion criteria. The Walrus was successfully tracked into distal vasculature and allowed therapeutic device delivery in all but 3 cases (0.9%). Large aspiration catheters ≥0.070 inch ID were used in 71.9% of cases. Stent retriever thrombectomy was used as the first-line modality in 59.2% and thromboaspiration in 40.8% of cases. The successful recanalization rate (modified treatment in cerebral ischemia (mTICI) 2b/3) was 94.4%, with 64.8% of the patients achieving mTICI 2b/3 after the first pass. The Walrus-related adverse event rate was 0.6%, corresponding to two vessel dissections. Functional independence was 50% (126/252) and mortality 25% (63/252). Unfavorable outcomes were more likely in older patients, who had unsuccessful reperfusion, longer procedure times, and a higher mean number of passes.ConclusionIn acute ischemic stroke patients presenting with large vessel occlusion, the Walrus BGC demonstrated excellent navigability and safety profile, allowed the accommodation of leading large bore aspiration catheters, and demonstrated high vessel recanalization rates.

Introduction: Underlying biological, genetic, or epigenetic characteristics may predispose to health differences and outcomes with COVID-19 associated stroke. Social determinants of health, access and geographical differences pertaining both to population density and other location-based factors may also be important. Methods: We report 69 cases of acute stroke in patients positive for SARS-CoV-2, in a dichotomized analysis of ischemic stroke outcomes between patients of African American background versus all other backgrounds. All patients presented to 14 major hospitals in the United States and Canada, from March 14-April 14, 2020. All patients had nasopharyngeal swab samples that were positive for SARS-CoV-2 on qualitative RT-PCR assays. Results: We found no significant difference in age (64.4 versus 62.9 years) or the proportion of females (51.9% versus 38.1%) (table 1). Diabetes mellitus was present significantly less in African American cases versus others (37% vs. 66.7%). The African American cohort had a similar mean NIHSS score of 16.3 compared with 14.9 in other races (p=0.63). The door-to-CT time was also similar (23 versus 19 minutes). The proportion of patients presenting with a large vessel occlusion was not significantly different (40.7% versus 47%). We noted 14.8% of African American cases received intravenous tPA compared to 31% in other races but was not significantly different. The proportion of thrombectomy cases mirrored this (14.8% versus 31%). Regarding stroke functional outcomes, there was no difference between African Americans and other races with respect to discharge mRS or proportion of favorable outcome (mRS 0-2). Symptomatic intracranial hemorrhage (sICH) was significantly higher for African Americans (11.1% versus 3%, p Discussion: The reasons for increased mortality in African Americans with COVID-19-associated stroke are unknown. The finding in this study that mortality rate of COVID-19 positive stroke patients is greater than that previously reported in either COVID-19 respiratory infection alone or acute ischemic stroke alone, suggests an interaction that also warrants further study.

Background Aneurysmal persistence after flow-diversion (FD) occurs in 5–25% of aneurysms which might necessitate further treatment. A frequently used retreatment paradigm utilizes the deployment of another flow-diverting device (FDD) in a telescoping fashion within the existing device. There are no current data evaluating this strategy. Methods A retrospective review of patients undergoing FD retreatment from 15 centers was performed, with inclusion criteria being repeat FD occurring for the same aneurysm at least 6 months after initial treatment, with minimum of 6 months of imaging follow-up after retreatment. Primary outcome was aneurysmal occlusion, and secondary outcomes were safety and complications. A multivariable logistic regression model was constructed to identify predictors of persistence/occlusion after retreatment. Comparative Kaplan-Meier curves were developed to assess the effect of early (6–12 months since initial treatment) vs late retreatment (>12 months since initial treatment) on the cumulative incidence of aneurysm occlusion over time. Results Ninety-five patients (median age 57, 81% females) harboring 95 aneurysms underwent 198 treatment procedures. In our cohort, 87.4% of aneurysms were unruptured; 74.7% were saccular and 79% were located in the internal carotid artery (median maximal diameter 9-mm), with 87 patients treated twice and 8 patients treated thrice. Median elapsed-time between first and second treatment was 12.2 months. Last available follow-up was performed at median of 12.8 months after retreatment, and median of 30.6 months after initial treatment, showing complete occlusion in 46.2%, and near-complete occlusion (90–99%) in 20.4% of aneurysms. No difference in ischemic complications following initial treatment and retreatment (4.2% vs 4.2; p>0.99). On multivariable logistic regression, fusiform morphology was associated with higher odds of non-occlusion after retreatment (OR 7.2; p=0.003), with history of hypertension and incorporated branch into aneurysms trending toward incomplete occlusion (p=0.055 and p=0.054; respectively). Family history of aneurysms and positive smoking history were associated with higher odds of complete occlusion (p=0.019 and p=0.026; respectively). Kaplan-Meier curves comparative estimators showed no significant difference in time-to-occlusion between the two groups (log rank test, p=0.48). Conclusion Repeat flow diversion for persistent aneurysms is safe and effective. Fusiform morphology is the strongest predictor of aneurysmal persistence after repeat flow diversion. Disclosures M. Salem: None. A. Sweid: None. A. Kuhn: None. A. Dmytriw: None. S. Gomez-Paz: None. G. Maragkos: None. M. Waqas: None. C. Parra-Farinas: None. A. Salehani: None. N. Adeeb: None. P. Brouwer: None. G. Pickett: None. M. Ghuman: None. V. Yang: None. A. Weill: None. C. Cognard: None. L. Renieri: None. P. Kan: None. N. Limbucci: None. V. Mendes Pereira: None. M. Harrigan: None. A. Puri: None. E. Levy: None. J. Moore: None. C. Ogilvy: None. T. Marotta: None. P. Jabbour: None. A. Thomas: None.