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BackgroundPlatelets and von Willebrand factor (vWF) are key components of acute ischemic stroke (AIS) emboli. We aimed to investigate the CD42b (platelets)/vWF expression, its association with stroke etiology and the impact these components may have on the clinical/procedural parameters.MethodsCD42b/vWF immunostaining was performed on 288 emboli collected as part of the multicenter STRIP Registry. CD42b/VWF expression and distribution were evaluated. Student’s t-test and χ2test were performed as appropriate.ResultsThe mean CD42b and VWF content in clots was 44.3% and 21.9%, respectively. There was a positive correlation between platelets and vWF (r=0.64, pConclusionsThe vWF level and CD42b/vWF distribution pattern in emboli were correlated with AIS etiology and revascularization outcome. Platelet content was associated with response to thrombolysis.

Background: Understanding clot composition may allow for better technical planning and improved outcomes in mechanical thrombectomy (MT). We sought to correlate clot composition with reperfusion outcomes in MT. Methods: Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin and eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of First-Pass Effect (mTICI2c/3, FPE) and the number of device passes. Results: A total of 1430 patients (mean age, 68.4±13.5years; median [IQR] baseline NIHSS,17.2 [10.5-23]; IV-tPA use, 36%; Stent-Retrievers [SR], 27%; Contact Aspiration [CA], 27%; Combined SR + CA, 43%) were included. The median [IQR] number of passes was 1 [1-2]. FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for RBC-rich (P Conclusion: Despite the lack of correlation between clot histology and FPE in the overall population, our study adds to the growing body of evidence supporting the notion that clot composition influences reperfusion treatment strategy outcomes. Additional studies are needed.

BackgroundCompositional and structural features of retrieved clots by thrombectomy can provide insight into improving the endovascular treatment of ischemic stroke. Currently, histological analysis is limited to quantification of compositions and qualitative description of the clot structure. We hypothesized that heterogeneous clots would be prone to poorer recanalization rates and performed a quantitative analysis to test this hypothesis.MethodsWe collected and did histology on clots retrieved by mechanical thrombectomy from 157 stroke cases (107 achieved first-pass effect (FPE) and 50 did not). Using an in-house algorithm, the scanned images were divided into grids (with sizes of 0.2, 0.3, 0.4, 0.5, and 0.6 mm) and the extent of non-uniformity of RBC distribution was computed using the proposed spatial heterogeneity index (SHI). Finally, we validated the clinical significance of clot heterogeneity using the Mann–Whitney test and an artificial neural network (ANN) model.ResultsFor cases with FPE, SHI values were smaller (0.033 vs 0.039 for grid size of 0.4 mm, P=0.028) compared with those without. In comparison, the clot composition was not statistically different between those two groups. From the ANN model, clot heterogeneity was the most important factor, followed by fibrin content, thrombectomy techniques, red blood cell content, clot area, platelet content, etiology, and admission of intravenous tissue plasminogen activator (IV-tPA). No statistical difference of clot heterogeneity was found for different etiologies, thrombectomy techniques, and IV-tPA administration.ConclusionsClot heterogeneity can affect the clot response to thrombectomy devices and is associated with lower FPE. SHI can be a useful metric to quantify clot heterogeneity.

BackgroundSeveral animal studies have demonstrated that mechanical thrombectomy (MT) for acute ischemic stroke (AIS) may cause vessel wall injury (VWI). However, the histological changes in human cerebral arteries following MT are difficult to determine.ObjectiveTo investigate the occurrence of VWI during MT by histological and immunohistochemical evaluation of AIS clots.MethodsAs part of the multicenter STRIP registry, 277 clots from 237 patients were analyzed using Martius Scarlett Blue stain and immunohistochemistry for CD34 (endothelial cells) and smooth muscle actin (smooth muscle cells).ResultsMT devices used were aspiration catheters (100 cases), stentriever (101 cases), and both (36 cases). VWI was found in 33/277 clots (12%). There was no significant correlation between VWI and MT device. The degree of damage varied from grade I (mild intimal damage, 24 clots), to grade II (relevant intimal and subintimal damage, 3 clots), and III (severe injury, 6 clots). VWI clots contained significantly more erythrocytes (p=0.006*) and less platelets/other (p=0.005*) than non-VWI clots suggesting soft thrombus material.Thrombolysis correlated with a lower rate of VWI (p=0.04*). VWI cases showed a significantly higher number of passes (2 [1–4] vs 1 [1–3], p=0.028*) and poorer recanalization outcome (p=0.01*) than cases without VWI.ConclusionsHistological markers of VWI were present in 12% of AIS thrombi, suggesting that VWI might be related to MT. VWI was associated with soft thrombus consistency, higher number of passes and poorer revascularization outcome. There was no significant correlation between VWI and MT device.

Background and purpose Flow diversion of aneurysms located in the M1 segment and middle cerebral artery bifurcation with Pipeline embolization device is sometimes performed, but further study is needed to support its regular use in aneurysm treatment. Here, we report measures of safety and efficacy for Pipeline embolization in the proximal middle cerebral artery in a multi-center cohort. Materials and methods Clinical and angiographic data of eligible patients were retrospectively obtained from participating centers and assessed for key clinical and angiographic outcomes. Additional details were extracted for patients with complications. Results In our multi-center cohort, complete aneurysm occlusion was achieved in 71% (17/24) of treated aneurysms. There were no deaths or disabling strokes, but non-disabling ischemic strokes occurred in 8% (2/24) of patients. For aneurysms in the M1 segment, complete aneurysm occlusion was observed in 75% (12/16) of aneurysms, aneurysm volume reduction was observed in 100% (16/16) of aneurysms, and non-disabling ischemic strokes occurred in 13% (2/16) of patients. For aneurysms at the middle cerebral artery bifurcation, complete aneurysm occlusion was observed in 63% (5/8) of aneurysms, aneurysm volume reduction occurred in 88% (7/8) of aneurysms, and ischemic or hemorrhagic complications occurred in 0% (0/8) of patients. Conclusion Pipeline embolization of cerebral aneurysms in the M1 segment and middle cerebral artery bifurcation demonstrated a 71% rate of complete aneurysm occlusion. There were no deaths or disabling strokes, but there was an 8% rate of non-disabling ischemic strokes.

Background and purpose Flow diversion is commonly used to treat intracranial aneurysms in various regions of the cerebral vasculature, but is only approved for use in the internal carotid arteries. Treatment of distal PICA aneurysms with PED is sometimes performed but has not been well studied. Here, we report our experience with flow diversion of distal PICA aneurysms with PED. Materials and methods Clinical and angiographic data of eligible patients was retrospectively obtained and assessed for key demographic characteristics and clinical and angiographic outcomes. Principal outcomes included rates of aneurysm occlusion, ischemic or hemorrhagic complication, technical complication, and in-stent stenosis. Results Three female and 2 male patients underwent placement of PED in the PICA for treatment of 5 distal PICA aneurysms. Clinical and angiographic follow-up was obtained for all patients. Complete aneurysm occlusion was observed in 100% (5/5) of treated aneurysms at 6 month and longest angiographic follow-up. While there were no ischemic or device-related complications, delayed hemorrhagic complications occurred in 20% (1/5) of patients. Conclusion Pipeline embolization of distal PICA aneurysms can be performed in select patients. Further study is necessary in larger cohorts to better define clinical scenarios in which flow diversion in the distal PICA should be considered.

Background and aim Mechanical thrombectomy (MT) for large vessel occlusion often requires multiple passes to retrieve the entire thrombus load. In this multi-institutional study we sought to examine the composition of thrombus fragments retrieved with each pass during MT. Methods Patients who required multiple passes during thrombectomy were included. Histopathological evaluation of thrombus fragments retrieved from each pass was performed using Martius Scarlet Blue staining and the composition of each thrombus component including RBC, fibrin and platelet was determined using image analysis software. Results 154 patients underwent MT and 868 passes was performed which resulted in 263 thrombus fragments retrieval. The analysis of thrombus components per pass showed higher RBC, lower fibrin and platelet composition in the pass 1 and 2 when compared to pass 3 and passes 4 or more combined (P values 0.05). Similarly, when each composition of thrombus fragments retrieved in pass 3 and passes 4 or more combined were compared with each other, no significant difference was noted (P values >0.05). Conclusion Our findings confirm that thrombus fragments retrieved with each pass differed significantly in histological content. Fragments in the first passes were associated with lower fibrin and platelet composition compared to fragments retrieved in passes three and four or higher. Also, thrombus fragments retrieved after failed pass were associated with higher fibrin and platelet components.

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.

Given recent evidence suggesting the clot composition may be associated with revascularization outcomes and stroke etiology, clot composition research has been a topic of growing interest. It is currently unclear what effect, if any, pre-thrombectomy thrombolysis has on clot composition. Understanding this association is important as it is a potential confounding variable in clot composition research. We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients who did and did not receive pre-treatment tPA to study the effect of tPA on clot composition.Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using Martius Scarlett Blue (MSB) staining and area of the clot was also measured on the gross photos. Student's t test was used for continuous variables and chi-squared test for categorical variables.A total of 1430 patients were included in this study. Mean age was 68.4±13.5 years. Overall rate of TICI 2c/3 was 67%. A total of 517 patients received tPA (36%) and 913 patients did not (64%). Mean RBC density for the tPA group was 42.97±22.62% compared to 42.80±23.18% for the non-tPA group (P=0.89). Mean WBC density for the tPA group was 3.74±2.60% compared to 3.42±2.21% for the non-tPA group (P=0.012). Mean fibrin density for the tPA group was 26.52±15.81% compared to 26.53±15.34% for the non-tPA group (P=0.98). Mean platelet density for the tPA group was 26.22±18.60% compared to 26.55±19.47% for the non-tPA group (P=0.75). tPA group also had significantly smaller clot area compared to non-tPA group.Our study 1430 retrieved emboli and ischemic stroke patients shows no interaction between tPA administration and clot composition. These findings suggest that tPA does not result in any histological changes in clot composition.

Introduction/Purpose Flow diversion of aneurysms located in the M1 segment and middle cerebral artery bifurcation with Pipeline embolization device is sometimes performed, but further study is needed to support its regular use in aneurysm treatment. Here, we report measures of safety and efficacy for Pipeline embolization in the proximal middle cerebral artery in a multi-center cohort. Materials and Methods Clinical and angiographic data of eligible patients undergoing Pipeline embolization of aneurysms located in the M1 segment and middle cerebral artery bifurcation were retrospectively obtained from participating centers and assessed for key clinical, angiographic, and cross-sectional imaging outcomes. Additional details were extracted for patients with complications. Results In our multi-center cohort, complete aneurysm occlusion was achieved in 71% (17/24) of treated aneurysms. There were no deaths or disabling strokes, but non-disabling ischemic strokes occurred in 8% (2/24) of patients. For aneurysms in the M1 segment, complete aneurysm occlusion was observed in 75% (12/16) of aneurysms, aneurysm volume reduction was observed in 100% (16/16) of aneurysms, and non-disabling ischemic strokes occurred in 13% (2/16) of patients. An illustrative example of an M1 aneurysm treated with PED is provided in figure 1. For aneurysms at the middle cerebral artery bifurcation, complete aneurysm occlusion was observed in 63% (5/8) of aneurysms, aneurysm volume reduction occurred in 88% (7/8) of aneurysms, and ischemic or hemorrhagic complications occurred in 0% (0/8) of patients. 19% (3/16) of patients that remained asymptomatic in the follow-up period and underwent cross-sectional imaging had clinically silent basal ganglia infarcts identified. Conclusion Pipeline embolization of cerebral aneurysms in the M1 segment and middle cerebral artery bifurcation demonstrated a 71% rate of complete aneurysm occlusion. There were no deaths or disabling strokes, but there was an 8% rate of non-disabling ischemic strokes. Further work is necessary to describe the long-term effects of silent basal ganglia infarcts caused by PED. Disclosures D. Lauzier: None. B. Root: None. Y. Kayan: 2; C; Microvention, Penumbra, Medtronic. J. Delgado Almandoz: 2; C; Medtronic, Microvention. J. Osbun: 2; C; Medtronic, Microvention. A. Chatterjee: None. K. Whaley: None. M. Tipps: None. C. Moran: 2; C; Medtronic, Cerenovus. A. Kansagra: 2; C; Penumbra, Microvention, iSchemaView.

Background The Pipeline Embolization Device (PED) has been increasingly used for the treatment of posterior circulation aneurysms. The purpose of the present study was to examine the clinical and angiographic outcomes of patients with vertebrobasilar aneurysms treated with the PED. Methods We performed a retrospective review of vertebrobasilar aneurysms treated with the PED at 4 high-volume neurovascular centers. Patient, aneurysm, and procedural data were collected, including perioperative and delayed complications. Aneurysm occlusion on follow-up imaging studies was defined as complete (100%), near-complete (>90%), or incomplete ( Results The cohort included 35 patients with 37 vertebrobasilar aneurysms who underwent 36 treatment sessions. Of the 35 patients, 10 were men (29%), and the mean patient age was 54.1 years (range, 32–75). Eight patients (23%) underwent urgent treatment because of a ruptured aneurysm (n = 6), brainstem perforator stroke (n = 1), or post-traumatic pseudoaneurysm (n = 1). Of the 37 aneurysms, 22 arose from the vertebral artery (59%) and 15 from the basilar artery (41%). Also, 19 were saccular aneurysms (51%), with a mean size of 7.7 mm (range, 1.7–38.0); 17 were fusiform aneurysms (46%), with a mean size of 11.0 mm (range, 4.3–34); and 1 was a 2.9-mm blister aneurysm. The overall procedural complication rate was 14% (5 of 36), including 3 neurologically symptomatic complications. At a mean follow-up period of 14 months (range, 3–59), 24 of 34 aneurysms (71%) were completely occluded and 29 of 34 (85%) were completely or near-completely occluded. Conclusion Our results show that Pipeline embolization of vertebrobasilar aneurysms is associated with acceptable occlusion and complication rates.

Background The Scepter XC is a dual-lumen balloon catheter that accommodates a 0.014-inch microwire and can be used for balloon-assisted coiling of cerebral aneurysms. We describe our experience with the use of this device. Methods Two high-volume institution neurointerventional databases were retrospectively reviewed for cerebral aneurysms treated with balloon-assisted coiling using the Scepter XC balloon catheter. Patient demographics, aneurysm characteristics, and procedural details were recorded. Major procedure-related neurologic complications were defined as events that caused an increase in modified Rankin Scale that persisted for more than 1 week after the procedure. Follow-up aneurysm occlusion was assessed using the Raymond-Roy classification. Results During the study period, 231 aneurysms were treated in 219 patients (152 women, 67 men) with a mean age of 58.4 ± 12.2 years. Mean aneurysm size was 6.1 ± 3.1 mm, with a mean neck diameter of 3.1 ± 1.3 mm. In total, 77.5% of aneurysms were wide necked, and 39.8% were treated in the setting of subarachnoid hemorrhage. The major complication rate was 0.9% (2/231) per treated aneurysm, including one stroke and one death related to intraoperative aneurysm rupture. Excluding patients who died, angiographic follow up was available for 85.3% (191/224) of aneurysms. During a mean follow up of 17.4 ± 13.0 months (range, 1.7–66.5 months), Raymond-Roy 1 and 2 occlusion rates were 56.5% (108/191) and 35.6% (68/191), respectively. The retreatment rate was 12.6% (24/191). Conclusion Our experience using the coaxial dual-lumen Scepter XC for balloon-assisted coiling demonstrates acceptable aneurysm occlusion and complication rates.

Background The Pipeline embolization device (PED) has expanded the range of aneurysms amenable to endovascular treatment, including some that were previously untreatable. The PED contains several metals, including nickel, cobalt, chromium, platinum, and tungsten. The safety of PED implantation in patients with cutaneous metal allergy is unknown. The aim of this study was to assess clinical and angiographic outcomes of PED treatment in patients with cutaneous metal allergy. Methods A single-institution neurointerventional database was retrospectively reviewed for patients with documented cutaneous metal allergy who were treated with the PED. Patient, aneurysm, and procedural data were collected, including perioperative and delayed complications. Posttreatment angiograms were reviewed for in-Pipeline stenosis and aneurysm occlusion. Results Twenty patients with metal allergy underwent 23 PED treatments for 26 aneurysms. The cohort was 95% (19/20) female; mean age was 55.7 years. Aneurysms were primarily anterior circulation (92%, 24/26) and saccular (92%; 24/26); mean size was 8.8 mm (range, 2–32 mm). One PED was implanted in 70% (14/20) of patients, 25% (5/20) had 2 devices placed, and 1 patient had 3 devices. One major procedural complication occurred (4.3%, 1/23) in which a stroke was caused by perioperative PED thrombosis. Angiographic follow-up was available for all patients (mean duration 15.7 months; range, 6–64 months), which demonstrated a complete aneurysm occlusion rate of 88% (23/26). Asymptomatic in-Pipeline stenosis occurred in 2 cases, resulting in 65% and 50% parent artery stenosis, respectively. Conclusions Preliminary results suggest that PED implantation in patients with cutaneous metal allergy is safe and effective.

The Scepter XC balloon catheter can be used for balloon-assisted coiling (BAC) of cerebral aneurysms but also accommodates delivery of a low-profile visible intraluminal stent (LVIS Jr.). We assessed the safety and effectiveness of BAC using the Scepter XC, with LVIS Jr. stent-assisted coiling (SAC) as a bailout option.A single-institution prospectively maintained neurointerventional database was reviewed for wide-necked (neck width ≥4 mm or dome/neck ratio2) saccular aneurysms treated using the Scepter XC. Complication and angiographic occlusion rates of BAC and SAC procedures were compared. Multivariate logistic regression was used to identify variables predictive of complete aneurysm occlusion.The cohort included 141 wide-necked saccular intracranial aneurysms treated in 135 procedures. SAC was used to treat 30% of aneurysms by deploying the LVIS Jr. through the Scepter XC. The overall procedural complication rate was 8.9%, including a 1.5% rate of symptomatic thromboembolic events and 3.0% rate of hemorrhagic complications, with no significant differences in complications between BAC and SAC procedures (P = 0.27). The overall complete or near-complete aneurysm occlusion rate was 96%, with trends toward higher complete aneurysm occlusion and lower retreatment rates with SAC (78 vs. 57%; P = 0.13; 0 vs. 8.4%, P = 0.13). Multivariate logistic regression identified aneurysm size, procedure technique (BAC or SAC), and duration of follow-up as independent predictors of complete aneurysm occlusion.Use of the Scepter XC for BAC, with LVIS Jr. SAC as a bailout option, shows acceptable angiographic and clinical results.

PurposeTo report the efficacy of A Direct Aspiration first-Pass Thrombectomy (ADAPT) technique with larger-bore ACE aspiration catheters as first-line treatment for anterior circulation emergent large vessel occlusions (ELVOs), and assess for the presence of a first-pass effect with ADAPT.MethodsWe retrospectively reviewed 152 consecutive patients with anterior circulation ELVOs treated with the ADAPT technique as first-line treatment using ACE60, 64, or 68 at our institution. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded.ResultsFifty-seven patients were treated with ACE60 (37.5%), 35 with ACE64 (23%), and 60 with ACE68 (39.5%). Median groin puncture to reperfusion time was 30 min with ACE60, 26 min with ACE64, and 19.5 min with ACE68. Successful reperfusion after the first ADAPT pass was 33% with ACE60 and 53% with ACE68 (P=0.04). The stent-retriever rescue rate was 26% with ACE60, 3% with ACE64, and 10% with ACE68 (P=0.004). In multivariate logistic regression analysis, use of the ACE68 aspiration catheter was an independent predictor of successful reperfusion after the first ADAPT pass (P=0.016, OR1.67, 95% CI 1.1 to 2.54), and successful reperfusion after the first ADAPT pass was an independent predictor of good clinical outcome at 90 days (P=0.0004, OR6.2, 95% CI 2.27 to 16.8).ConclusionUse of the larger-bore ACE 68 aspiration catheter was associated with shorter groin puncture to reperfusion time, higher rate of successful reperfusion after the first ADAPT pass, and lower rate of stent-retriever rescue. Further, a first-pass effect was demonstrated in our ADAPT patient cohort.

Flow diversion is a viable alternative for treatment of wide-neck and fusiform aneurysms originating from the posterior inferior cerebellar artery (PICA), but coverage of the PICA and vertebral perforating arteries may be a concern. The aim of this study was to examine procedural, clinical, and angiographic outcomes of patients with PICA aneurysms treated with the Pipeline Embolization Device.Retrospective review was performed of PICA aneurysms treated with the Pipeline device at 3 neurovascular centers, including periprocedural complications and clinical and angiographic outcomes.In 16 procedures, 14 PICA aneurysms were treated with the Pipeline device. These included 11 saccular aneurysms with a mean size of 7.4 mm (range, 2.0-11.1 mm) and 3 fusiform aneurysms with a mean diameter of 6.1 mm (range, 5.0-8.0 mm) and mean length of 10.3 mm (range, 6.0-15.0 mm). One patient developed a PICA territory infarct with mild leg weakness that resolved in7 days. Overall complication rate was 7% (1/14) per patient and 6% (1/16) per procedure. Mean duration of clinical follow-up was 13.5 months (range, 3 weeks to 61.7 months), with all patients returning to baseline functional status. Complete or near-complete aneurysm occlusion was achieved in 58% (7/12) of cases with angiographic follow-up (mean, 15 months; range, 4-61 months). All covered PICAs remained patent.Flow diversion of PICA aneurysms is a safe and viable treatment option when traditional endovascular options are unlikely to preserve parent vessel patency.

Background Flow diversion of posterior cerebral artery (PCA) aneurysms has not been widely reported, possibly owing to concerns regarding parent vessel size and branch vessel coverage. Objective To examine the safety and effectiveness of PCA aneurysm flow diverter treatment. Methods Retrospective review of PCA aneurysms treated with the Pipeline Embolization Device (PED; Medtronic Inc, Dublin, Ireland) at 3 neurovascular centers, including periprocedural complications and clinical and angiographic outcomes. Systematic review of the literature identified published reports of PCA aneurysms treated with flow diversion. Rates of aneurysm occlusion and complications were calculated, and outcomes of saccular and fusiform aneurysm treatments were compared. Results Ten PCA aneurysms in 9 patients were treated with the PED. There were 2 intraprocedural thromboembolic events (20%), including 1 symptomatic infarction and 1 delayed PED thrombosis. Eight of 10 patients returned to or improved from their baseline functional status. Complete aneurysm occlusion with parent vessel preservation was achieved in 75% (6/8) of cases at mean follow-up of 16.7 mo. Eleven of 12 (92%) major branch vessels covered by a PED remained patent. Including the present study, systematic review of 15 studies found a complete aneurysm occlusion rate of 88% (30/34) and complication rate of 26% (10/38), including 5 symptomatic ischemic strokes (13%; 5/38). Fusiform aneurysms more frequently completely occluded compared with saccular aneurysms (100% vs 70%; P = .03) but were associated with a higher complication rate (43% vs 9%; P = .06). Conclusion The safety and effectiveness profile of flow diverter treatment of PCA aneurysms may be acceptable in select cases.

ObjectiveTo evaluate the safety and effectiveness of the Flow Redirection Endoluminal Device (FRED) flow diverter in support of an application for Food and Drug Administration approval in the USA.Methods145 patients were enrolled in a prospective, single-arm multicenter trial. Patients with aneurysms of unfavorable morphology for traditional endovascular therapies (large, wide-necked, fusiform, etc) were included. The trial was designed to demonstrate non-inferiority in both safety and effectiveness, comparing trial results with performance goals (PGs) established from peer-reviewed published literature. The primary safety endpoint was death or major stroke (National Institutes of Health Stroke Scale score ≥4 points) within 30 days of the procedure, or any major ipsilateral stroke or neurological death within the first year. The primary effectiveness endpoint was complete occlusion of the target aneurysm with ≤50% stenosis of the parent artery at 12 months after treatment, and in which an alternative treatment of the target intracranial aneurysm had not been performed.Results145 patients underwent attempted placement of a FRED device, and one or more devices were placed in all 145 patients. 135/145 (93%) had a single device placed. Core laboratory adjudication deemed 106 (73.1%) of the aneurysms large or giant. A safety endpoint was experienced by 9/145 (6.2%) patients, successfully achieving the safety PG of 46% aneurysm occlusion was also achieved, with the effectiveness endpoint being met in 80/139 (57.6%)ConclusionAs compared with historically derived performance benchmarks, the FRED flow diverter is both safe and effective for the treatment of appropriately selected intracranial aneurysms.Clinical registration numberNCT01801007

Background and purpose Flow diversion may have advantages in the treatment of posterior communicating artery (PComA) aneurysms associated with a fetal origin posterior cerebral artery (PCA), which can be challenging to treat with conventional techniques. However, a PComA incorporated into the aneurysm may prevent or delay aneurysm occlusion. Also, coverage of a fetal origin PCA risks infarction of a large vascular territory. The purpose of this study was to examine the safety and effectiveness of using the Pipeline Embolization Device (PED) to treat PComA aneurysms associated with a fetal origin PCA. Patients and methods Retrospective review of PComA aneurysms associated with a fetal origin PCA treated with the PED at two neurovascular centers was performed. Periprocedural complications and clinical and angiographic outcomes were reviewed. Results Seven female patients underwent a total of seven PED procedures to treat seven PcomA aneurysms associated with a fetal origin PCA. The symptomatic complication rate was 14% (1/7) per patient and 13% (1/8) per procedure. Angiographic follow up was obtained for 6 of 7 aneurysms. Follow-up DSA at 5–7 months after treatment demonstrated complete occlusion of 17% (1/6) of aneurysms. One aneurysm was retreated with a second PED and occlusion was demonstrated 36 months after the second treatment, yielding an overall complete occlusion rate of 33% (2/6). Conclusions PED treatment was largely ineffective at treating PComA aneurysms associated with a fetal origin PCA, and should only be considered when conventional treatment options, including microsurgical clipping, are not feasible.

Background and Purpose— Nearly 30% of large vessel occlusion acute ischemic stroke clots are from an unknown source. We assessed histological clot composition in a series of patients with large vessel occlusion and investigated correlations between clot composition and stroke pathogenesis. Methods— As part of the multi-institutional STRIP registry (Stroke Thromboembolism Registry of Imaging and Pathology), consecutive emboli retrieved during mechanical thrombectomy were stained using Martius Scarlett Blue and analyzed using machine learning software. We assessed proportions of red blood cells, fibrin, platelets, and white blood cells. Correlations between clot components and stroke pathogenesis (large artery atherosclerosis, cardioembolism, and stroke of undetermined pathogenesis) were assessed using SPSS22. Results— One hundred five patients were included. The proportion of platelet-rich clots (55.0% versus 21.2%; P =0.005) and percentage of platelet content (22.1±4.2% versus 13.9±14.2%; P =0.03) was significantly higher in the large artery atherosclerosis group compared with the cardioembolic group. The proportion of platelet-rich clots (50.0% versus 21.2%; P =0.024) was also significantly higher in the cryptogenic group compared with cardioembolic cases. Large artery atherosclerosis and cryptogenic cases had a similar proportion of platelet-rich clots (55.0% versus 50.0%; P =0.636). There was no significant difference between stroke pathogenesis and the other major clot components. Conclusions— High platelet content of emboli is associated with a large artery atherosclerosis etiology of large vessel occlusion.

BackgroundThe aim of this publication is to provide a detailed update on the diagnosis, treatment, and endovascular techniques for posterior circulation emergent large vessel occlusion (pc-ELVO).MethodsWe performed a review of the literature to specifically evaluate this disease and its treatments.ResultsData were analyzed, and recommendations were reported based on the strength of the published evidence and expert consensus.ConclusionWhile many questions about pc-ELVO remain to be studied, there is evidence to support particular practices in its evaluation and treatment.

BackgroundCurrent studies on clot characterization in acute ischemic stroke focus on fibrin and red blood cell composition. Few studies have examined platelet composition in acute ischemic stroke clots. We characterize clot composition using the Martius Scarlet Blue stain and assess associations between platelet density and CT density.Materials and methodHistopathological analysis of the clots collected as part of the multi-institutional STRIP registry was performed using Martius Scarlet Blue stain and the composition of the clots was quantified using Orbit Image Analysis (www.orbit.bio) machine learning software. Prior to endovascular treatment, each patient underwent non-contrast CT (NCCT) and the CT density of each clot was measured. Correlations between clot components and clinical information were assessed using the χ2 test.ResultsEighty-five patients were included in the study. The mean platelet density of the clots was 15.7% (2.5–72.5%). There was a significant correlation between platelet-rich clots and the absence of hyperdensity on NCCT, (ρ=0.321, p=0.003*, n=85). Similarly, there was a significant inverse correlation between the percentage of platelets and the mean Hounsfield Units on NCCT (ρ=−0.243, p=0.025*, n=85).ConclusionMartius Scarlet Blue stain can identify patients who have platelet-rich clots. Platelet-rich clots are isodense on NCCT.

IntroductionVariable response to clopidogrel can impact perioperative risk in elective endovascular intracranial aneurysm treatment. The present study aims to determine the efficacy of a two-test protocol in reaching in-range preoperative P2Y12 reaction units (PRU) of 60–240 and the rate of postoperative conversion to hyper-response.MethodsA 17-day two-test protocol (with tests on days 10 and 17) for patients starting clopidogrel in anticipation of elective endovascular intracranial aneurysm treatment was introduced in February 2013 at our institution. Records for patients started on this protocol through December 2014 were reviewed for preoperative and postoperative PRUs, patient and procedural data, and thromboembolic and hemorrhagic events within 30 days. Logistic regression analyses were performed to identify predictors of postoperative hyper-response (pResults103 patients (80 women) of mean age 57 years were included. 74 patients (71.8%) were in range at the first test and 92 patients (89.3%) were in range at the second test. A postoperative test was performed in 82 patients (79.6%) at a median of 9 days. 51 patients (62.2%) converted into hyper-responders. There were five non-disabling strokes and one intracranial hemorrhage within 30 days. There were no major strokes (modified Rankin Scale score >2) or deaths. There was no association between out-of-range PRU and thromboembolic or hemorrhagic neurological complications.ConclusionsThe protocol achieves in-range preoperative PRU by the second test in almost nine of 10 patients. Nearly two-thirds of patients exhibited postoperative hyper-response to clopidogrel. Out-of-range PRU was not associated with thromboembolic or hemorrhagic neurological complications in this cohort of patients with actively managed P2Y12 inhibition.

Delayed ipsilateral intraparenchymal hemorrhage (IPH) has been reported following technically successful treatment of intracranial aneurysms using flow-diverting stents in up to 8.5 % of patients. We report a similar, though less frequent phenomenon in the setting of stent-assisted coil embolization. Institutional review board approval was obtained. A retrospective analysis of a prospective neurointerventional procedure registry was performed to review all IPHs that occurred in aneurysm patients within 90 days of endovascular treatment performed between November 2002 and November 2014 at one institution. Age, sex, hypertension, dual antiplatelet therapy, and technical details of the procedure were recorded. A total of 1697 patients underwent endovascular treatment of an intracranial aneurysm without a flow diverter at our institution during the study period. Among these, 138 patients underwent stent-assisted coiling (8.1 %). Of these, three patients (2.2 %) suffered a delayed IPH within the vascular territory distal to the treated lesion (one woman, median age 60 years). Recently described in the setting of flow diversion, delayed ipsilateral IPH is not limited to flow-diverting stents. Though less frequent, a potential for this complication may exist following any intracranial stenting procedure, possibly related to hemorrhagic conversion of microembolic phenomena in the setting of dual antiplatelet or anticoagulation therapy.

Background The pathophysiology of delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH) may include platelet activation and microthrombi formation. Antiplatelet therapy may reduce the incidence of DCI and improve clinical outcomes after aSAH. This study compared outcomes among aSAH patients receiving aspirin monotherapy versus dual antiplatelet therapy (DAPT). Methods Aneurysmal subarachnoid hemorrhage patients treated at a single institution between November 2011 and December 2017 were divided according to whether they received aspirin monotherapy or DAPT after endovascular treatment. Baseline characteristics and outcomes of the groups were compared, including incidences of delayed cerebral ischemia, bleeding complications, symptomatic vasospasm, in-hospital mortality, and functional status 6 months after discharge. Results During the study period, 142 patients met study inclusion criteria, of which 123 were treated with aspirin monotherapy (87 %) and 19 were treated with DAPT (13 %). There was no statistically significant difference between the aspirin monotherapy and DAPT groups with respect to incidences of delayed cerebral ischemia (4.9 vs 10.5 %; p = 0.32), symptomatic vasospasm (13.0 vs 15.8 %; p = 0.74), or good clinical outcome at 6-month follow up (73.3 vs 66.7 %; p = 0.56). The DAPT group experienced a higher incidence of in-hospital mortality (21 vs 5.7 %; p = 0.02), but DAPT did not remain independently predictive of this outcome on regression analysis. There was a trend toward a higher bleeding complication rate in the DAPT group (0.8 vs 5.3 %; p = 0.13). Conclusions DAPT does not reduce the incidence of DCI or improve outcomes in aSAH patients, and may increase the risk of clinically significant bleeding complications.

Background The Scepter XC balloon catheter can be used for balloon-assisted coiling (BAC) of cerebral aneurysms, but also accommodates delivery of a low profile visible intraluminal stent (LVIS Jr.). We assessed the safety and effectiveness of BAC using the Scepter XC, with LVIS Jr. stent-assisted coiling (SAC) as a bailout option. Methods A single-institution prospectively-maintained neurointerventional database was retrospectively reviewed for wide-necked (neck width ≥4 mm or dome-to-neck ratio Results The cohort included 169 wide-necked saccular intracranial aneurysms treated in 157 procedures. SAC was used to treat 25% of aneurysms by deploying the LVIS Jr through the Scepter XC. The overall procedural complication rate was 11%, including 3.2% rates of symptomatic thromboembolic and hemorrhagic complications, with no significant differences in complications between BAC and SAC procedures (p=0.26). The overall complete aneurysm occlusion rate was 59%, with trends toward higher complete aneurysm occlusion and lower retreatment rates with SAC (78 vs 54%, p=0.07; 0 vs 9.3%, p=0.10). Multivariate logistic regression identified aneurysm size, procedure technique (BAC or SAC), and duration of follow up as independent predictors of complete aneurysm occlusion. Conclusions Initial experience using the Scepter XC for BAC, with LVIS Jr. SAC as a bailout option, demonstrates acceptable angiographic and clinical results. Disclosures A. Wallace: None. Y. Kayan: 2; C; Medtronic, Penumbra, Microvention. J. Delgado Almandoz: 2; C; Medtronic, Penumbra, Microvention, Accriva. J. Fease: None. A. Milner: None. J. Scholz: None. M. Thomas: None.

Purpose To determine the correlation of serum S100B protein levels with clinical outcome and the presence of DWI abnormalities in acute subarachnoid hemorrhage (SAH). Methods Patients with diffuse SAH at our institution were offered enrollment in a prospective study in which serial MRI, including DWI, FLAIR, PWI, and ASL sequences, was performed at admission, 7 days, 30 days, and upon the development of signs/symptoms of vasospasm. As well, serum S100B levels were measured at the time of each MRI. Patient demographics, Hunt-Hess grade, modified Fisher score, and underlying lesion and treatment technique were recorded. Poor clinical outcome was defined as mRS 3–6 at discharge. Mean S100B levels were compared using Student’s t-test. ROC analyses were performed using MedCalc v18.2.1. p Results Between November 2013 and August 2017, 50 patients were enrolled, 37 women, mean age 58, 20 current smokers. Hunt-Hess grade mean was 3.0. Modified Fisher score mean was 3.5. All underlying vascular lesions were treated endovascularly: 17 ACA aneurysms, 14 ICA aneurysms (including PCOM), 10 MCA aneurysms, 3 basilar tip aneurysms, 1 vertebral aneurysm, 1 posterior fossa AVM, and 4 angiographically-negative SAHs. Mean serum S100B was 73.4 ng/L, 55.1 ng/L and 57.8 ng/L on admission, at 7 days and 30 days, respectively. Overall, serum S100B was significantly higher on admission than at 7 days (p=0.01). Admission serum S100B was significantly higher in patients with poor outcome at discharge (p=0.0003) and in patients with any DWI abnormalities on admission (p=0.0004). The correlation of elevated serum S100B with the presence of DWI abnormalities persisted at 7 days (60.7 ng/L versus 42.8 ng/L, p=0.007). ROC analyses revealed a cutoff of admission S100B>69 ng/L resulting in a sensitivity of 54.8% and a specificity of 94.7% for poor outcome at discharge with an AUC of 0.74 (95% CI 0.60–0.85, p=0.0005), and a cutoff of admission S100B>61 ng/L resulting in a sensitivity of 64.5% and a specificity of 82.4% for the presence of any DWI abnormalities on admission with an AUC of 0.75 (95% CI 0.61–0.86, p=0.0004). Conclusion Admission S100B levels were elevated in setting of acute subarachnoid hemorrhage. Higher S100B levels were associated with poor outcomes at discharge and the presence of DWI abnormalities, both on admission and at 7 days. Disclosures Y. Kayan: 2; C; Medtronic, Penumbra. J. Delgado Almandoz: 2; C; Medtronic, MicroVention, Penumbra. J. Fease: None. A. Wallace: None. J. Scholz: None. A. Milner: None. N. Banerji: None. M. Mulder: None.

Introduction The Pipeline Embolization Device (PED) has greatly expanded the range of aneurysms amenable to endovascular treatment, including those with wide necks that incorporate branch vessels. Published occlusion rates of anterior circulation aneurysms treated with the PED typically exceed 85%1–7 with morbidity rates of less than 7%.7 8 Prompted by this success, the PED is being increasingly utilized for the off-label treatment of posterior circulation aneurysms with widely varying results.9 10 The purpose of this study was to examine the procedural, clinical, and angiographic outcomes of patients with vertebrobasilar aneurysms treated with the PED. Methods Retrospective review of the neurointerventional databases of three high-volume neurovascular centers was approved by respective institutional review boards to identify patients with vertebrobasilar aneurysms treated with the PED between 2012 and December 2016. Demographic, clinical, and angiographic data were collected from electronic medical records. Procedural details, including devices used and peri-procedural complications, were collected from operative reports. Preoperative digital subtraction angiography was reviewed to determine the morphological characteristics of treated aneurysms, including largest diameter in any dimension, location, shape, and incorporated branch vessels. Follow-up angiographic images were also reviewed for intra-PED stenosis and patency of branch vessels covered by the PED. Results During the study period, 27 patients with 29 vertebrobasilar aneurysms underwent 28 treatments with the PED. The patients were 37% (10/27) men and 63% (17/27) women with a mean age of 53.3 years (range, 32–75 years), 44% (12/27) of whom were previous or current smokers. 74% (20/27) of patients were asymptomatic at presentation. Six of the remaining patients presented with subarachnoid hemorrhage (SAH; 22%, 6/27) and one patient presented with stroke related to thrombosis of brainstem perforators incorporated into the aneurysm (3.7%, 1/27). Aneurysm locations included the basilar trunk (41%, 12/29), basilar tip (7%, 2/29), vertebral artery (VA) proximal to the posterior inferior cerebellar artery (PICA; 10%, 3/29), VA at the PICA origin (10%, 3/29), and post-PICA VA (17%, 5/29). There were 15 saccular aneurysms (50%) with a mean size of 8.1 mm (range, 1.7–38 mm), 13 fusiform aneurysms (47%) with mean size of 11.8 mm (range, 4.3–34 mm) and length of 11.4 mm (range, 3.4–33), and one 2.9 mm blister aneurysm. The overall procedural complication rate was 18% (5/28), and the neurologic morbidity and mortality rate was 11% (3/28). Excluding aneurysms in patients who died, angiographic follow up was available for 96% (26/27) of patients. Mean duration of follow up was 12 months (range, 3–59 months). At last angiographic follow up, 67% (18/27) of aneurysms were completely occluded and 81% (22/27) were completely or near-completely occluded. A total of 36 branch vessels in 21 patients were covered by at least one PED. At last angiographic follow up, 8% (3/36) of covered branch vessels were occluded, none of which were symptomatic. Conclusion Pipeline embolization of vertebrobasilar aneurysms is associated with a higher complication rate and lower occlusion rate compared with anterior circulation aneurysms, but may be a viable treatment option in select cases. Disclosures A. Wallace: None. M. Kamran: None. T. Madaelil: None. Y. Kayan: 2; C; Medtronic, Penumbra, MicroVention. A. Kansagra: None. J. Grossberg: None. J. Delgado Almandoz: 2; C; Medtronic, Penumbra, Microvention, Accriva Diagnostics. C. Moran: 2; C; Medtronic. A. Roy: None. D. Cross: None. B. Howard: None. C. Cawley: None. J. Dion: None. T. CreveCoeur: None. J. Osbun: 1; C; MicroVention.

Purpose To determine the natural history of diffusion weighted imaging (DWI) abnormalities in early acute subarachnoid hemorrhage (SAH). Methods Patients with diffuse SAH at our institution were offered enrollment in a prospective study in which serial MRI, including DWI, FLAIR, PWI, and ASL sequences, was performed at admission, 7 days, 30 days, and upon the development of signs/symptoms of vasospasm. Patient demographics, Hunt-Hess grade, modified Fisher score, and underlying lesion and treatment technique were recorded. Results Between November 2013 and August 2017, 50 patients were enrolled, 37 women, mean age 58, 20 current smokers. Hunt-Hess grade mean was 3.0. Modified Fisher score mean was 3.5. All underlying vascular lesions were treated endovascularly: 17 ACA aneurysms, 14 ICA aneurysms (including PCOM), 10 MCA aneurysms, 3 basilar tip aneurysms, 1 vertebral aneurysm, 1 posterior fossa AVM, and 4 angiographically-negative SAHs. 31 patients (62%) had DWI abnormalities on their admission scan; all had undergone a catheter angiogram or endovascular treatment of the underlying lesion prior to the MRI. The total number of DWI abnormalities amongst these patients was 250 (214 At 7 days, the total number of DWI abnormalities was 267 (224 Conclusion The acquisition of additional multifocal ischemic injury to the brain is common in early SAH. This phenomenon is independent of cerebral perfusion and large-vessel vasospasm. Disclosures Y. Kayan: 2; C; Medtronic, Penumbra. J. Delgado Almandoz: 2; C; Medtronic, MicroVention, Penumbra. J. Fease: None. A. Wallace: None. J. Scholz: None. A. Milner: None. N. Banerji: None. M. Mulder: None.

Purpose To determine recanalization and post-treatment rupture rates in a large cohort of patients with intracranial aneurysms treated with simple or balloon-assisted coil embolization. Methods We retrospectively reviewed consecutive patients with intracranial aneurysms treated with simple or balloon-assisted coil embolization at our institution from August 8th, 1995 to September 30th, 2017. Baseline aneurysm and patient characteristics, procedural variables and angiographic outcomes were recorded. Aneurysm recanalization was defined as Raymond 3 or Raymond 2 with a neck remnant ≥4 mm or ≥33% of initial aneurysm volume. Multivariate regression analysis was performed to identify independent variables associated with aneurysm recanalization. Results 1634 patients with 1935 intracranial aneurysms were included, 1196 women (73%), mean age 56 years (median 56 years, 8–97 years). 1125 aneurysms were incidental (58.1%), 752 ruptured (38.9%) and 58 symptomatic (3%). Mean aneurysm size 6.3 mm (median 5.5 mm, 1.6–27.9 mm), mean neck 3 mm (median 2.8 mm, 0.6–16.2 mm), mean dome-to-neck ratio 1.7 (median 1.5, 0.7–6.5). Aneurysm locations: 502 ICA (25.9%), 461 Acomm (23.8%), 375 MCA (19.4%), 276 Pcomm (14.3%), 128 basilar tip (6.6%), 79 other ACA (4.1%) and 114 other posterior circulation (5.9%). 749 aneurysms were treated with simple coiling (38.7%) and 1186 with balloon-assisted coiling (61.3%), mean packing density 33.4% (median 31.5%, 6.5%–94.9%). Angiographic follow-up was completed in 1574 of 1730 aneurysms available (91%), mean time to last follow-up 5.3 years (median 4.4 years, 0–20.5 years). Aneurysm occlusion at last follow-up was Raymond 1 in 878 aneurysms (55.8%), Raymond 2 in 496 aneurysms (31.5%), and Raymond 3 in 200 aneurysms (12.7%). There were 254 aneurysm recanalizations at last follow-up (16.1%), and 202 aneurysms were retreated (12.8%). Table 1 summarizes independent predictors of aneurysm recanalization in our cohort. Table 2 summarizes recanalization rates by location and rupture status. 13 aneurysms ruptured after coiling (0.8%), corresponding to an annual post-treatment rupture rate of 0.15%. Mean time from treatment to rupture was 5.8 years (median 4.5 years, 0–12.7 years). Mean time from last angiographic evaluation to rupture was 2.2 years (median 1 year, 0–10.2 years). Aneurysm occlusion at the last angiographic evaluation prior to rupture was Raymond 1 in 4 aneurysms, Raymond 2 in 3 aneurysms, and Raymond 3 in 6 aneurysms. 12 post-treatment ruptures occurred in aneurysms treated before 1/1/2008. Conclusion Endovascular aneurysm treatment with coils alone is associated with relatively high long-term recanalization and post-treatment rupture rates, especially after treatment of ruptured aneurysms. Long-term angiographic follow-up and early retreatment of recanalized aneurysms would be prudent. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Microvention/Terumo, Penumbra, Inc. Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra, Inc. A. Wallace: None. J. Fease: None. J. Scholz: None. A. Milner: None. M. Mulder: None.

Introduction Balloon-assisted coiling (BAC) is a well-established technique for treatment of wide-necked cerebral aneurysms. The Scepter XC (Microvention, Tustin, California, USA) is a dual-lumen balloon catheter that can be used for aneurysm-neck remodeling, protection of branch vessels arising from or near the aneurysm neck, and stabilization of the microcatheter during coil deployment. The lumen also accommodates a 0.014 inch microwire. We describe our initial experience with the use of this device for BAC of cerebral aneurysms. Methods Two high-volume institution neurointerventional databases were retrospectively reviewed for cerebral aneurysms treated with BAC using the Scepter XC balloon catheter. Wide-neck aneurysms were defined as those with a neck width ≥4 mm or a dome-to-neck ratio 10 mm, or DSA and rated using the Raymond-Roy classification. Results During the study period, 231 aneurysms were treated in 219 patients (152 women, 67 men) with a mean age of 58.4±12.2 years. Mean aneurysm size was 6.1±3.1 mm, with a mean neck diameter of 3.1±1.3 mm. 77.9% (180/231) of aneurysms were wide-necked, and 39.8% (92/231) were acutely ruptured at the time of treatment. The overall complication rate was 12.1% (28/231) per treated aneurysm, including a 4.8% (11/231) rate of symptomatic thromboembolic events, 8.6% (8/92) rate of intraoperative rupture when treating acutely ruptured aneurysms, and 1.4% (2/139) rate of intraoperative aneurysm rupture in elective cases. Excluding patients who died, DSA or MRA follow up was available for 85.3% (191/224) of aneurysms. During a mean follow-up of 17.4±13.0 months (range, 1.7–66.5 months), Raymond-Roy 1oc and 2oc clusion rates were 56.5% (108/191) and 35.6% (68/191), respectively. The retreatment rate was 13% (24/191). Conclusions Balloon-assisted coiling using the dual coaxial lumen Scepter XC demonstrates acceptable aneurysm occlusion and complication rates. Disclosures A. Wallace: None. E. Samaniego: 2; C; Medtronic, Microvention. Y. Kayan: 2; C; Medtronic, Penumbra, Microvention. C. Derdeyn: None. J. Delgado: 2; C; Medtronic, Penumbra, Microvention, Accriva. B. Zheng: None. J. Fease: None. M. Thomas: None. J. Scholz: None. A. Milner:None. S. Ortega: 2; C; Stryker Neurovascular, Medtronic.

Purpose To report the efficacy of A Direct Aspiration first-Pass Thrombectomy (ADAPT) technique with evolving ACE aspiration catheter technology as first-line treatment for anterior circulation emergent large vessel occlusions (ELVOs) and assess for the presence of a first pass effect with ADAPT. Methods We retrospectively reviewed 152 consecutive patients with anterior circulation ELVOs treated with the ADAPT technique as first-line treatment using ACE 60, 64 or 68 at our institution. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded. Results Fifty-seven patients were treated with ACE 60 (37.5%), 35 with ACE 64 (23%) and 60 with ACE 68 (39.5%). Median groin puncture to reperfusion time was 30 min with ACE 60, 26 min with ACE 64, and 19.5 min with ACE 68. Successful reperfusion after the first ADAPT pass was 33% with ACE 60% and 53% with ACE 68 (p=0.04). Of note, successful reperfusion after the first ADAPT pass was achieved in 23 of 33 patients with M1 occlusions treated with ACE 68 in our cohort (69.7%). The stent-retriever rescue rate was 26% with ACE 60, 3% with ACE 64% and 10% with ACE 68 (p=0.004). The rate of embolus to a new territory was 5.3% with ACE 60, 2.9% with ACE 64% and 1.7% with ACE 68 (p=0.5). The rate of intracranial vascular injury was 1.8% with ACE 60, 5.7% with ACE 64% and 5% with ACE 68 (p=0.5). The symptomatic intracranial hemorrhage rate was 1.8% with ACE 60, 5.7% with ACE 64% and 6.7% with ACE 68 (p=0.4). At 90 days, a good clinical outcome, mRS 0–2, was achieved in 70 patients (46.1%), while 27 patients had mRS 3 (17.8%), 22 mRS 4–5 (14.5%), and 33 expired (21.7%). In multivariate logistic regression analysis, use of the ACE 68 aspiration catheter was an independent predictor of successful reperfusion after the first ADAPT pass (p-value 0.016, OR 1.67, 95% CI 1.1–2.54), while successful reperfusion after the first ADAPT pass was an independent predictor of good clinical outcome at 90 days (p-value 0.0004, OR 6.2, 95% CI 2.27–16.8). Conclusion Use of the ACE 68 aspiration catheter was associated with shorter groin puncture to reperfusion times, higher rates of successful reperfusion after the first ADAPT pass, and lower rates of stent-retriever rescue. Further, a first pass effect was demonstrated in our ADAPT patient cohort. Disclosures J. Delgado Almandoz: 2; C; Penumbra, Inc. Y. Kayan: 2; C; Penumbra, Inc. A. Wallace: None. R. Tarrel: None. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. M. Mulder: None. M. Young: None.

Purpose To evaluate the safety and efficacy of the Low-profile Visualized Intraluminal Support (LVIS) Jr stent for treatment of intracranial aneurysms. Methods We conducted a retrospective review of all consecutive patients with intracranial aneurysms treated with the LVIS Jr stent between June 4th, 2014 and March 31 st, 2018 at our institution. Baseline patient and aneurysm characteristics, procedural variables, complications and aneurysm occlusion at follow-up were recorded. Results 81 patients underwent 91 procedures to treat 95 intracranial aneurysms using the LVIS Jr stent, 59 women (73%), mean age 59.1 years (median 60 years, 32–83 years). 42 aneurysms were incidental (44%), 41 recurrent (43%), 9 ruptured (10%), and 3 symptomatic (3%). Mean aneurysm size was 6.3 mm (median 5.2 mm, 1.5–31.3 mm), mean neck 3.8 mm (median 2.9 mm, 0.9–13.7 mm), mean dome-to-neck ratio 1.4 (median 1.3, 0.6–2.7). Aneurysm locations were: 36 anterior communicating artery, 26 middle cerebral artery (MCA), 12 basilar tip, 10 anterior cerebral artery, 4 internal carotid artery, 2 posterior communicating artery, 2 vertebral artery and 1 each posterior inferior cerebellar, superior cerebellar and posterior cerebral arteries. Aneurysm embolization techniques were: 91 stent-assisted coiling (96%) and 4 flow diversion (4%). Y-stenting was used for 13 aneurysms (14%), T-stenting for 2 aneurysms (2%) and X-stenting for 1 aneurysm (1%). The LVIS Jr was deployed via a Scepter XC balloon in 49 procedures (54%). Mean packing density was 40% (median 38.5%, 8.8%–90.9%), mean procedure time was 83 min (median 74 min, 35–201 min). The table summarizes treatment-related complications in our cohort. There were no intra-procedural aneurysm/vessel perforations. There were 4 treatment-related complications resulting in a disabling neurological deficit or death (modified Rankin Scale>2, 4.4%). These were 1 MCA perforator infarction on post-operative day (POD) 0; 1 subacute T-stent thrombosis on POD 4; 1 rectus sheath hematoma after percutaneous feeding tube placement leading to severe anemia, hypotension and left MCA territorial infarction on POD 21 in a patient with a ruptured aneurysm; and 1 delayed basilar artery perforator infarction 7 months after Y-stenting of a recurrent giant basilar tip aneurysm. Treatment-related mortality was 2.5%, overall neurological mortality 6.2%. Angiographic follow-up was performed in 58 aneurysms (66%, 30 aneurysms pending follow-up). Follow-up was completed with MR angiography in 54 aneurysms (93%) and catheter angiography in 4 aneurysms (7%). Mean time to last follow-up was 14.1 months (median 6.5 months, 2.9–38.4 months). At last follow-up, 41 aneurysms were completely occluded (70.7%, Raymond 1), 12 had residual neck (20.7%, Raymond 2) and 5 had residual aneurysm (8.6%, Raymond 3). 5 aneurysms were retreated (8.6%). Conclusion The LVIS Jr stent is a safe and effective tool for the treatment of intracranial aneurysms, achieving high medium-term complete/near complete aneurysm occlusion rates with low treatment-related morbidity and mortality and low re-treatment rates. Disclosures J. Delgado Almandoz: 2; C; Microvention/Terumo. Y. Kayan: None. A. Wallace: None. J. Scholz: None. A. Milner: None. J. Fease: None. M. Mulder: None.

Introduction The Pipeline Embolization Device (PED; Medtronic Neurovascular, Irvine, CA) has expanded the spectrum of aneurysms amenable to endovascular treatment. The device is a braided mesh cylinder composed of 48 strands of 25% platinum and 75% cobalt-nickel alloy. An estimated 17% of women and 3% of men are allergic to nickel, and the safety PED implantation in these patients is a concern. The purpose of this study was to assess the clinical and angiographic outcomes of PED treatment in patients with nickel allergy. Methods A single institution neurointerventional database was retrospectively reviewed for patients treated with the PED who had a documented nickel allergy. In some patients patch testing was performed preoperatively, consisting of taping a PED to the patient’s skin for 1 week. Patient demographics, aneurysm characteristics, and procedural details were recorded. All patients received dual antiplatelet therapy for approximately 17 days before treatment, and response was assessed with VerifyNow (Accriva Diagnostics; San Diego, CA). Follow-up digital subtraction angiography was performed 6 months post procedure. Longer-term follow up was performed with CT angiography when PED alone was used or MRA with and without contrast when adjunctive coiling was performed. Follow-up functional status was graded using the modified Rankin Scale (mRS). Good clinical outcome was defined as mRS ≤2 at last clinical follow up. Results During the study period, 22 patients with documented nickel contact dermatitis underwent 23 PED treatments for 29 aneurysms. Patch testing was performed in 55% (12/22) of patients, none of whom experienced a skin reaction. The cohort included 21 women and 1 man with a mean age of 53.6±14 years. Patient medical comorbidities were as follows: hypertension, 40.9%; hyperlipidemia, 9.1%; type 2 diabetes mellitus, 0%. 36% (8/22) of patients actively smoked at the time of treatment. Mean aneurysm size was 8.8±8.1 mm (range, 2.0–32.0 mm), with 93% (27/29) located in the anterior circulation and 7% (2/29) in the posterior circulation. No aneurysms were treated in the setting of subarachnoid hemorrhage. Most patients were treated with a single PED (79.3%, 23/29). Five patients were treated with two PEDs and one was treated with three PEDs. 28% (8/29) of aneurysms were treated with adjunctive coiling. 18% (4/22) of patients experienced a symptomatic complication, all of which were thromboembolic, but all patients (100%, 22/22) had a good clinical outcome. During a mean angiographic follow-up of 16.2±13.0 months (range, 3–64 months), complete and near-complete (>90%) occlusion rates were 77% (20/26) and 4% (1/26), respectively. Endothelial hyperplasia occurred in one case (3%), which resulted in approximately 65% asymptomatic parent artery stenosis. Conclusion All patients with nickel allergy treated with the PED had a good clinical outcome, but the thromboembolic complication rate was higher than typically reported for PED series. Further research is needed to determine if nickel allergy is an independent risk factor for procedural complications. Disclosures A. Wallace: None. J. Delagado Almandoz: 2; C; Medtronic, Penumbra, Accriva, Microvention. Y. Kayan: 2; C; Medtronic, Penumbra, Microvention. J. Fease: None. M. Thomas: None. J. Scholz: None. A. Milner: None.

Acute ischemic stroke (AIS) is the fifth leading cause of death, and remains the leading cause of disability in the USA.1 There are an estimated 680 000 new strokes per year in the USA, with a mortality rate of 53–94%, and with an even greater morbidity.2 It is estimated that 3–22% of these patients are candidates for endovascular therapy.3–6 In addition to baseline stroke severity, emergent large vessel occlusion (ELVO) has been shown to be an independent predictor of poor outcome at 6 months.3 4 While intravenous recombinant tissue plasminogen activator (IV r-tPA) has proven efficacious predominantly for small cerebral vessel occlusions, endovascular therapies, including stent retriever based, aspiration based mechanical thrombectomy techniques, and intra-arterial administration of thrombolytic agents, have been shown to achieve higher rates of recanalization in patients with ELVO.7–10 The purpose of this document is to provide an update and critical assessment of technical aspects of the mechanical thrombectomy procedure. This document was prepared by the Standards and Guidelines Committee of the Society of NeuroInterventional Surgery (SNIS), a multidisciplinary society representing the leaders in the field of endovascular therapy for cerebrovascular disease. A review of the English language literature published between January 1998 and March 2016 was conducted using search terms that included: ‘stroke,’ ‘ischemic stroke,’ ‘large vessel occlusion,’ ‘thrombectomy,’ ‘mechanical thrombectomy,’ ‘neurointerventional,’ ‘tPA,’ and ‘technique.’ Additionally, we incorporated already existing guidelines published by the American Heart Association (AHA) and the SNIS.11–15 The strength of the evidence supporting each recommendation was summarized using a scale previously described by the AHA guideline panels, and by the University of Oxford, Centre for Evidence Based Medicine.13 15–18 Much of our current practice in mechanical thrombectomy derives from recent randomized controlled trials (RCTs) which provide a foundation for treatment goals. The online supplementary tables 1-3 provide details of these thrombectomy trials, and …

Introduction Larger bore reperfusion catheters have been designed to increase the effectiveness of direct aspiration for treatment of acute ischemic stroke due to large vessel occlusions. The present study has two goals: 1. To compare the reperfusion rate of the newest large bore reperfusion catheter, ACE68, with previous generations of ACE catheters, ACE64 and ACE60, and 2. To compare the cost associated with three first-line approaches to mechanical thrombectomy: ADAPT using evolving ACE technology, Solumbra, and stent-retriever (SR) with balloon-guide catheter (BGC). Methods The prospectively populated acute stroke intervention database at our institution was retrospectively reviewed for mechanical thrombectomies performed using the ADAPT technique as a first-line approach from July 2013 through February 2017. Successful reperfusion (defined as TICI 2b/3) rates amongst the successive generations of ACE reperfusion catheters were compared. The costs of the procedures were also compared, including the costs of salvage therapy using adjunctive devices when necessary (additional reperfusion catheters or SR). These costs were then compared to the costs of hypothetically performing these procedures using Solumbra or SR as first-line approaches. List prices for devices were used in the cost comparison. The two-tailed Fisher’s exact test was used for the reperfusion rate comparisons, and Student’s t-test was used for the cost comparisons with p Results Between July 2013 and February 2017, 131 ADAPT cases were performed using ACE reperfusion catheters. There were 42 cases using the ACE68 as first-line, with a successful reperfusion rate using aspiration alone of 90% (38 of 42). This was significantly higher than with previous generations of ACE as first-line, where the rate of successful reperfusion was 73% using aspiration alone (65 of 89 cases, p=0.02). The rate of successful reperfusion with a single aspiration pass was higher with ACE68 compared to previous generations (50% versus 37%) but this difference was not statistically significant (p=0.19). Overall successful reperfusion was similar when SR was used as salvage therapy (95% with ACE68 as first-line versus 85% with previous ACE generations, p=0.14). Out of 131 patients, 15% (n=20) required the use of SR after aspiration alone, with an improvement to TICI 2b/3 in 13 patients (65%). For ADAPT cases with salvage therapy included, the average device cost per case was not significantly different comparing previous ACE devices with ACE68: $6669 and $6,650, respectively. An ADAPT approach with any ACE catheter including the cost of salvage therapy resulted in significant cost savings compared to having hypothetically performed these procedures using Solumbra or SR as first-line with costs per case of $12,440 and $10,195, respectively, not including salvage therapy. Total costs for all patients for ADAPT, SR, and Solumbra were $866,150, $1,325,350, and $1,617,200, respectively. Conclusion ADAPT with the ACE68 reperfusion catheter resulted in a significantly higher rate of successful reperfusion using aspiration alone (90%) compared to previous generation ACE catheters. ADAPT also resulted in significant cost savings compared to Solumbra or SR first-line approaches. Disclosures Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra. J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Penumbra. M. Young: None. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. M. Mulder: None. A. Wallace: None. R. Tarrel: None.

Purpose This study9s goal is to evaluate the safety and efficacy of the Axium Prime Extra Soft (ES) coil for treatment of intracranial aneurysms. Methods We conducted a retrospective review of all consecutive patients with intracranial aneurysms treated with Axium Prime ES coils at a single center between January 26th, 2016 and March 28th, 2017. Baseline patient and aneurysm characteristics, procedural variables and complications were recorded. Aneurysm occlusion at angiographic follow-up was determined using the Roy-Raymond scale. Aneurysm retreatment was recorded. Results 45 patients with 48 intracranial aneurysms were included, 36 women (80%). Mean age was 58.2 years (median 58 years, 36–92 years). 47 aneurysms were treated successfully with coils (98%). 17 aneurysms were ruptured (35%), 8 recurrent (17%) and 3 symptomatic (6%). Mean maximum aneurysm size was 5.7mm (median 5.2mm, 2.2-26.2mm), mean neck 2.8mm (median 2.6mm, 1-6.2mm), mean dome to neck ratio 1.7 (median 1.4, 0.9-11.5). Aneurysm locations were: 13 anterior communicating artery, 11 middle cerebral artery, 10 internal carotid artery, 5 anterior cerebral artery, 4 posterior communicating artery, 1 basilar tip, and 1 each posterior inferior cerebellar, superior cerebellar, posterior cerebral and persistent hypoglossal arteries. Aneurysm embolization techniques were: 23 balloon-assisted coiling (48%), 11 stent-assisted coiling (23%), 10 simple coiling (21%), 3 Pipeline/coiling (6%), and 1 aneurysm was treated with flow diversion after attempted coiling (2%). Mean total number of coils deployed per aneurysm was 3.5mm (median 3, 1-14). Mean number of Axium Prime ES coils deployed per aneurysm was 2.1mm (median 2, 1-7). Mean Axium Prime ES coil length as total coil length percentage was 55.1% (median 42%, 11.1-100%). Mean packing density was 35.2% (median 35.7%, 1.6-63%). There were 6 peri-procedural complications: 3 coil herniations during balloon-assisted coiling requiring stenting (6%), 1 intra-operative aneurysm re-rupture controlled with balloon inflation (2%), 1 small peripheral subarachnoid hemorrhage on post-operative day 1 (2%), and 1 subacute stent thrombosis on post-operative day 4 (2%). The subacute stent thrombosis resulted in the patient’s death (2.2%). No other treatment-related complication resulted in a permanent neurological deficit or death. Overall mortality was 4.4%. Angiographic follow-up was performed in 19 aneurysms (42%, 26 aneurysms currently pending follow-up). Follow-up was completed with MR angiography in 17 aneurysms (90%) and catheter angiography in 2 aneurysms (10%). Mean time to follow-up was 6.3 months (median 6.1 months, 5.9-7.6 months). At follow-up, 14 aneurysms were completely occluded (74%, Raymond 1) and 5 showed residual neck (26%, Raymond 2). There were no residual aneurysms at follow-up (Raymond 3). No aneurysms were retreated. Conclusion The Axium Prime ES coil is safe and effective for the treatment of intracranial aneurysms, achieving high packing densities, low risk of major treatment-related complications, high medium-term complete/near-complete aneurysm occlusion rates, and low re-treatment rates. Disclosures: J. Delgado Almandoz: 2; C; Medtronic Neurovascular. Y. Kayan: 2; C; Medtronic Neurovascular. J. Scholz: None. A. Milner: None. A. Wallace: None. J. Fease: None. M. Mulder: None.

Purpose To examine clinical and angiographic outcomes in a cohort of consecutive patients with posterior circulation intracranial aneurysms treated with the Pipeline Embolization Device (PED) at a referral center. Methods We conducted a retrospective review of all patients with posterior circulation intracranial aneurysms treated with the PED in our center between January 23 rd , 2012 and January 24 th , 2017. Baseline patient and aneurysm characteristics, intra-­operative, peri-­operative and delayed complications were recorded. Aneurysm volumes in initial and follow-­up angiographic studies were calculated using AngioCalc. Clinical outcomes were categorized using the modified Rankin Scale (mRS). Results 17 patients underwent 18 PED procedures to treat 19 posterior circulation intracranial aneurysms during the study period. 12 patients were women (71%) and 5 men (29%). Mean age was 60 years (range 13-­80 years). 16 patients were premedicated with aspirin/clopidogrel with VerifyNow testing (94%), and 1 with aspirin/ticagrelor without VerifyNow testing (6%). 8 aneurysms were incidental (42%), 5 symptomatic (26%, 2 from mass effect), 4 recurrent (21%) and 3 ruptured (16%). 6 aneurysms were fusiform (32%), 3 dissecting (16%) and 2 blister (11%). 7 aneurysms were located in the basilar trunk (37%), 4 in the posterior inferior cerebellar artery (21%), 2 in the superior cerebellar artery (10.5%), 2 in the posterior cerebral artery (10.5%), 2 in the vertebral artery (10.5%), 1 in the basilar tip (5%) and 1 in a basilar perforator artery (5%). Mean aneurysm size was 8.8mm (1.7-34mm), mean neck was 6.7mm (0.6-32.6mm), mean dome-­to-­neck ratio was 1.3 (0.2-2.9). 12 aneurysms were wide-neck (≥4mm, 63%). Mean number of PEDs deployed per aneurysm was 1.3. Adjunctive coiling was performed in 4 aneurysms (21%). There were 2 intra-operative (11%), 3 peri-operative (17%) and 1 delayed (5.6%) complications, none led to a disabling neurological deficit (mRS≥3). There was no treatment-related mortality. There were no post-­operative aneurysm ruptures. Overall mortality was 5.9%. Angiographic follow-­up was available in 15 aneurysms (79%, 3 follow-ups currently pending), with a mean time to last angiographic follow-­up of 23.7 months (median 11 months, range 3.3-61.3 months). At last follow­-up, 11 aneurysms were completely occluded (73%), 3 aneurysms had incomplete occlusion (20%, mean 59.2% volume reduction), and 1 aneurysm had volume increase (7%, 166% increase). The enlarging aneurysm was re-treated with parent artery sacrifice (7%). Conclusion The PED is a safe and effective treatment for wide-neck posterior circulation intracranial aneurysms, with high long-term complete aneurysm occlusion rates, low re-­treatment rates, and a low rate of major treatment-related complications. Disclosures: J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Accriva Diagnostics. Y. Kayan: 2; C; Medtronic Neurovascular. J. Scholz: None. K. Uittenbogaard: None. A. Milner: None. J. Fease: None. A. Wallace: None. K. Nelson: None. M. Mulder: None.

Background and Purpose The Pipeline Embolization Device (PED; Covidien, Irvine, CA) is being increasingly utilized for off-label indications, but has not been widely utilized to treat posterior cerebral artery (PCA) aneurysms. Potential concerns regarding placement of the PED in the PCA include the relatively small parent vessel diameter and coverage of major branch vessels and P1 thalamic perforators. Herein, we report our experience using the PED for the treatment of PCA aneurysms. Materials and Methods Institutional review board approval was obtained to retrospectively review the neurointerventional databases of three high-volume neurovascular centers for PCA aneurysms treated with the PED between January 2012 and January 2016. Demographic information, clinical history, and outcomes were collected from electronic medical records. Procedural details and periprocedural complications were collected from operative reports. Preoperative digital subtraction angiography (DSA) was reviewed to determine aneurysm characteristics and anatomy of surrounding branch vessels. Follow up MR and DSA were reviewed for aneurysm occlusion, stenosis within the PED, and the status of branch vessels covered by the PED. Results The study included 10 PCA aneurysms in 9 patients (3 men, 6 women) with a mean age of 56 years (range, 18–74 years). There were 6 saccular aneurysms with a mean aneurysm size of 12.3 mm (range, 7–16 mm), and 4 fusiform aneurysms with mean size of 6.2 mm (range, 3.9–11.0 mm) and mean length of 18.8 mm (range, 5–45 mm). Eight aneurysms were treated with a single PED, and two aneurysms were treated with two PEDs. The PEDs ranged from 2.5–4.25 mm in diameter and 12–35 mm in length. Six of 10 PEDs were deployed entirely within the PCA. In two patients, the PED extended from the PCA into the basilar artery, covering the contralateral PCA and both superior cerebellar arteries. There were no deaths. There were two intraprocedural thromboembolic events (20%; 2/10), one of which resulted in symptomatic infarction (10%; 1/10), and one case of delayed PED thrombosis (10%; 1/10). Angiographic follow up was obtained for 9 of 10 aneurysms, including MRA for two patients, DSA for five patients, and DSA at 6 months and CTA at 24 months for one patient. The mean duration of angiographic follow up was 16.7 months (range, 2–33 months). Excluding the case of delayed parent vessel thrombosis, complete aneurysm occlusion was achieved in 75% (6/8) of cases at longest follow up during the study period. There were no instances of in-stent stenosis. All major branch vessels covered by a PED were patent at last angiographic follow. Conclusions PED embolization may be a viable treatment option for select PCA aneurysms that may be considered under appropriate clinical circumstances. Disclosures A. Wallace: None. J. Grossberg: None. J. Delgado Almandoz: None. M. Kamran: None. A. Roy: None. Y. Kayan: None. M. Austin: None. B. Howard: None. C. Moran: 2; C; Medtronic Neurovascular, Microvention. M. Cawley: None. D. Cross: None. J. Dion: None. A. Kansagra: None. J. Osbun: None.

Purpose To evaluate the effectiveness of the Penumbra system with ACE reperfusion catheters only (ACE only) versus ACE followed by Solitaire stent-retriever rescue (Solumbra rescue) for the treatment of anterior circulation emergent large vessel occlusions (ELVOs). Methods We performed a single center, retrospective review of 100 consecutive patients with anterior circulation ELVOs treated with ACE as first-line therapy. If successful revascularization (TICI 2b-3) was not achieved with ACE only, then Solumbra rescue was utilized. Baseline characteristics, procedural variables, and modified Rankin Scale (mRS) at 90 days were recorded. Results 84 patients were treated with ACE only and 16 patients required Solumbra rescue. 53 patients received iv-tPA prior to mechanical thrombectomy. Overall successful revascularization for all 100 consecutive patients was 90%, with puncture to reperfusion time of 38.7 min, embolization to new territory rate of 5%, and post-procedure symptomatic intracranial hemorrhage rate of 3% (2 subarachnoid, 1 intraparenchymal). Successful revascularization using ACE only was achieved in 78 patients (38 after a single pass), while 12 of the 16 patients requiring Solumbra rescue were successfully revascularized (75%). Puncture to reperfusion time for ACE only versus Solumbra rescue were 30.5 and 81.8 min, respectively (p Conclusion Aspiration thrombectomy using the Penumbra system with ACE reperfusion catheters is an effective first-line treatment for anterior circulation ELVOs, with the option to use adjunctive stent-retriever devices if aspiration alone is not sufficient. Advancements in reperfusion catheter technology from ACE 60 to ACE 68 have resulted in shorter procedural times and reduced need for adjunctive stent-retriever device use. Disclosures J. Delgado Almandoz: 2; C; Penumbra, Inc, Medtronic Neurovacular. Y. Kayan: 2; C; Penumbra, Inc, Medtronic Neurovacular. M. Young: None. J. Scholz: None. A. Milner: None. J. Fease: None. P. Roohani: None. A. Wallace: None. M. Mulder: None. R. Tarrel: None.

Purpose The Penumbra Coil 400 System (PC400) was designed with increased coil diameter to enhance filling efficiency in large intracranial aneurysms. This study9s goal is to evaluate the safety and efficacy of the PC400 coils to treat large intracranial aneurysms. Methods We conducted a retrospective review of all consecutive patients with intracranial aneurysms treated with PC400 coils at a single center. Baseline patient and aneurysm characteristics, procedural variables and treatment-related complications were recorded. Aneurysm occlusion at the time of last angiographic follow-up was determined using the Roy-Raymond scale. Aneurysm retreatment was recorded. Results 57 consecutive patients with 60 intracranial aneurysms were included, 44 women (77%). Mean age was 60.7 years (median 60 years, 28–89 years). 12 aneurysms were ruptured (20%). Mean maximum aneurysm size was 12mm (median 10.5mm, 5.2-22mm), mean neck size was 5mm (median 4.1mm, 1.9-15mm), mean dome to neck ratio was 2 (median 1.9, 0.8-4.2). Aneurysm locations were: 27 internal carotid artery, 10 middle cerebral artery, 8 posterior communicating artery, 6 basilar tip, 5 anterior communicating artery, and 1 each posterior inferior cerebellar, superior cerebellar, posterior cerebral and anterior cerebral arteries. Aneurysm embolization techniques were: 30 balloon-assisted coiling (50%), 18 simple coiling (30%), 8 Pipeline/coiling (13%), 3 stent-assisted coiling (5%), and 1 parent artery sacrifice (2%). 49 aneurysms were treated with PC400 coils only (82%). Mean number of PC400 coils deployed was 5.1 (median 4, 1-23), mean packing density was 34% (median 33.5%, 7-68%). Mean procedure time was 64 minutes (median 53 minutes, 23–186 minutes). There were 6 peri-procedural complications: 2 intra-operative aneurysm ruptures (3.3%), 1 coil herniation requiring stenting (1.7%), and 3 post-operative infarctions with permanent deficits (5%). Angiographic follow-up was available in 54 aneurysms (90%), mean time to last follow-up 12.2 months (median 6.5 months, 3.3-33.4 months). At last follow-up, 25 aneurysms were completely occluded (46%, Raymond 1), 20 showed residual neck (37%, Raymond 2), and 9 demonstrated residual aneurysm (17%, Raymond 3). Nine aneurysms were retreated (17%), 6 with flow-diversion and 3 with stent assisted-coiling. Compared to a prior study examining 84 large aneurysms treated with conventional coils, treatment with PC400 coils resulted in higher packing densities, faster procedure times, lower procedural complications and lower retreatment rates (Tables 1 and 2). Conclusion The PC400 system is safe and effective for the treatment of large wide-neck intracranial aneurysms, achieving high packing densities, fast procedural times, favorable safety profile and low re-treatment rates compared to conventional coiling. Disclosures: J. Delgado Almandoz: 2; C; Penumbra, Inc. Y. Kayan: 2; C; Penumbra, Inc. J. Fease: None. J. Scholz: None. A. Milner: None. A. Wallace: None. M. Mulder: None.

Purpose To examine clinical and angiographic outcomes in a cohort of consecutive patients with recurrent intracranial aneurysms treated with the Pipeline Embolization Device (PED) at a referral center. Methods We conducted a retrospective review of all patients with recurrent intracranial aneurysms treated with the PED in our center center between December 13 th , 2011 and March 29 th , 2017. Baseline patient and aneurysm characteristics, intra-­operative, peri-­operative and delayed complications were recorded. Aneurysm volumes in initial and follow-­up angiographic studies were calculated using AngioCalc. Clinical outcomes were categorized using the modified Rankin Scale (mRS). Results 50 patients underwent 53 PED procedures to treat 56 recurrent intracranial aneurysms during the study period. 36 patients were women (72%) and 14 men (28%). Mean age was 58 years (range 29–­77 years). 23 patients were active smokers (46%) and 26 had a prior history of subarachnoid hemorrhage (52%). 46 patients were premedicated with aspirin/clopidogrel (92%), 3 with aspirin/prasugrel (6%) and 1 with warfarin/clopidogrel (2%). All patients underwent pre-procedure VerifyNow testing. 46 aneurysms were recurrent after simple coiling (82%), 5 after PED embolization (9%, 1 after PED/coiling), 3 after stent-assisted coiling (5%), 1 after Onyx HD500 embolization (2%) and 1 after surgical clipping (2%). 4 aneurysms were symptomatic from mass effect (7%) and 1 was acutely ruptured (2%). 3 aneurysms were fusiform (5%) and 1 blister (2%). 39 aneurysms were located in the internal carotid artery (70%), 8 in the middle cerebral artery (14%), 5 in the anterior cerebral artery (9%), 3 in the posterior inferior cerebellar artery (5%) and 1 in the basilar tip (2%). 30 aneurysms had a vessel arising from the aneurysm dome/neck (54%), 14 of which were the posterior communicating artery (47%). Mean aneurysm size was 6.2 mm (1.5–26.2 mm), mean neck was 3.9 mm (0.5–9.3 mm), mean dome-­to-­neck ratio was 1.6 (0.6–11.5). 24 aneurysms were wide-neck (≥4 mm, 43%). Mean number of PEDs deployed per aneurysm was 0.9. Adjunctive coiling was performed in 7 aneurysms (12.5%, mean 4.7 coils deployed). 28 aneurysms were treated with PED Flex (50%). There were 4 intra-operative (7.5%), 15 peri-operative (28%) and 3 delayed (5.7%) complications. 1 peri-operative complication, an ipsilateral intracerebral hemorrhage on post-operative day 4 in a patient with P2Y12 reception over-inhibition at the time of the hemorrhage, resulted in the patient’s death (1.9%). No other treatment-related complication led to a disabling neurological deficit or death (mRS ≥3). Treatment-related mortality was 2%. There were no post-­operative aneurysm ruptures. Angiographic follow-­up was available in 47 aneurysms (86%, 8 follow-ups currently pending), with a mean time to last angiographic follow-­up of 20 months. At last follow­-up, 36 aneurysms were completely occluded (77%), 2 aneurysms had near-completed occlusion (4%, mean 97.3% vol reduction), and 9 aneurysms had incomplete occlusion (19%, mean 68.7% vol reduction). No aneurysms required retreatment. Conclusion The PED is a safe and effective treatment for recurrent intracranial aneurysms, with high long-term complete aneurysm occlusion rates, low re-­treatment rates, and a low rate of major treatment-related complications. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Accriva Diagnostics. Y. Kayan: 2; C; Medtronic Neurovascular. J. Fease: None. K. Uittenbogaard: None. J. Scholz: None. A. Milner: None. K. Nelson: None. A. Wallace: None. M. Mulder: None.

Flow diversion constitutes a pivotal advancement in endovascular intracranial aneurysm treatment, but requires development of a new skill set. The aim of this study is to determine whether outcomes after treatment with the Pipeline Embolization Device improve with experience. We retrospectively reviewed all patients with intracranial aneurysms treated with Pipeline at two centers over a 4.5-year period. Baseline patient and aneurysm characteristics, complications, and angiographic outcomes were analyzed. One hundred forty patients underwent 150 Pipeline procedures to treat 167 intracranial aneurysms during the study period, 109 women, mean age 55.4 years. One hundred twenty-six aneurysms were ICA, mean size 10.2 mm and mean neck 6.4 mm. Intra-procedural technical difficulties were higher during the first 75 procedures compared with the subsequent 75 (13.3 vs 2.7%; p = 0.03), as combined major morbidity and neurological mortality (14.7 vs 4%; p = 0.046). In multivariate regression analysis, increased operator experience with Pipeline remained an independent predictor of intra-procedural technical difficulties (p = 0.02, odds ratio (OR) 0.015, 95% CI 0.0004–0.55) and combined major morbidity and neurological mortality (p = 0.03, OR 0.16, 95% CI 0.03–0.84). At last follow-up, 123 aneurysms were completely occluded (81.5%, mean 24 months). In our cohort, age ≤ 53 years was an independent predictor of complete aneurysm occlusion at last follow-up (p = 0.001, OR 0.92, 95% CI 0.88–0.97). Five aneurysms were retreated (3.3%). The Pipeline embolization device is an effective treatment for intracranial aneurysms. The risk of intra-procedural technical difficulties and combined major morbidity and neurological mortality decreases significantly with increased operator experience in Pipeline deployment and patient management.

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

PurposeTo compare rates of symptomatic intracranial hemorrhage (SICH) and good clinical outcome at 90 days in patients with ischemic strokes from anterior circulation emergent large vessel occlusions (ELVO) treated with mechanical thrombectomy using either Solumbra or A Direct Aspiration first-Pass Thrombectomy (ADAPT) techniques.MethodsWe compared clinical characteristics, procedural variables, and clinical outcomes in patients with anterior circulation ELVOs treated with mechanical thrombectomy using either a Solumbra or ADAPT technique at our institution over a 38-month period. SICH was defined using the SITS-MOST criteria. A good clinical outcome was defined as a modified Rankin Scale score of 0–2 at 90 days.ResultsOne hundred patients were included, 55 in the Solumbra group and 45 in the ADAPT group. Patients in the ADAPT group had higher National Institutes of Health Stroke Scale (NIHSS) (19.2 vs 16.8, p=0.02) and a higher proportion of internal carotid artery terminus thrombi (42.2% vs 20%, p=0.03) than patients in the Solumbra group. Patients in the ADAPT group had a trend toward a lower rate of SICH than patients in the Solumbra group (2.2% vs 12.7%, p=0.07). Patients in the ADAPT group had a significantly higher rate of good clinical outcome at 90 days than patients in the Solumbra group (55.6% vs 30.9%, p=0.015). Use of the ADAPT technique (OR 6 (95% CI 1.0 to 31.2), p=0.049) was an independent predictor of a good clinical outcome at 90 days in our cohort.ConclusionsIn our cohort, the ADAPT technique was associated with significantly higher good clinical outcomes at 90 days in patients with acute ischemic stroke due to anterior circulation ELVOs treated with mechanical thrombectomy.

Purpose To compare procedural and clinical outcomes in patients with anterior circulation acute ischemic strokes treated with mechanical thrombectomy using ADAPT technique only or ADAPT with Solumbra salvage. Materials and methods We restrospectively reviewed a consecutive cohort of patients with anterior circulation acute ischemic strokes treated with mechanical thrombectomy using ADAPT technique only or ADAPT with Solumbra salvage at our institution between March 11th, 2013 and December 31st, 2015. Baseline clinical and radiological characteristics and procedural variables were recorded. Clinical outcomes at 90 days were recorded using the modified Rankin Scale (mRS). Results Fifty-nine patients were included, 33 male (56%). Mean age 67.1 years, mean admission NIHSS 19.1. Forty-six patients were treated with ADAPT only (78%) and 13 with ADAPT with Solumbra salvage (22%). Table 1 summarizes baseline clinical and radiological characteristics. There was a trend towards a higher proportion of patients with ICA terminus thrombi in the ADAPT with Solumbra salvage group (69.2%, p-value 0.054). Table 2 summarizes the procedural variables. There was a significantly-lower mean time from puncture to reperfusion in the ADAPT only group (29.5 minutes) compared to the ADAPT with Solumbra salvage group (85.1 minutes, p-value Conclusion Among patients treated with mechanical thrombectomy using an ADAPT-first approach, those requiring Solumbra salvage had significantly-higher rates of unfavorable clinical outcome and death at 90 days. Disclosures J. Delgado Almandoz: 2; C; Medtronic Neurovascular, Penumbra, Inc. Y. Kayan: 2; C; Medtronic Neurovascular, Penumbra, Inc. M. Young: None. J. Fease: None. J. Scholz: None. A. Milner: None. P. Roohani: None. T. Hehr: None. M. Mulder: None. R. Tarrel: None.

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.

Following mechanical mitral valve replacement surgery, a 69-year-old woman had an ischemic stroke in the right middle cerebral artery territory. Mechanical thrombectomy showed the embolus to be a piece of chordae tendineae excised during the valve replacement surgery.