Search

Background Pericallosal artery aneurysm treatment may be challenging using traditional endovascular techniques. Objective To demonstrate the feasibility, efficacy, and safety of endovascular treatment of pericallosal artery aneurysm using flow diverters. Methods We performed a retrospective review of our institutional database from July 2013 through July 2016 and identified 7 subjects with a pericallosal artery aneurysm treated with the Pipeline embolization device (ev3 Neurovascular, Medtronic, Dublin, Ireland) and at least 1 follow-up angiogram. Technical feasibility, procedural complication, angiographic results, and clinical outcome were evaluated. Results Placement of the Pipeline embolization device was successful in all cases without evidence of procedural complication. Five out of 7 subjects showed a complete aneurysm occlusion at 6- to 12-mo follow-up angiogram. The 2 subjects with persistent aneurysm filling showed decreased aneurysm sac volume on follow-up angiograms (96% and 60%). There was no evidence of in-implant stenosis or intimal hyperplasia. No thromboembolic or hemorrhagic complications were seen during the follow-up period. Only 1 patient had a transient change in Modified Rankin scale score from baseline as a result of different unrelated procedure. Conclusion Our preliminary results demonstrate feasibility of the use of flow diverter stent for treatment of aneurysms of the pericallosal artery with rate of aneurysm occlusion comparable to literature and without evidence of increased procedural or short-term morbidity. A long-term and larger cohort study is needed to validate our findings.

BACKGROUND AND PURPOSE: Advancements in medical device and imaging technology as well as accruing clinical evidence have accelerated the growth of the endovascular treatment of cerebrovascular diseases. However, the augmented role of these procedures raises concerns about the radiation dose to patients and operators. We evaluated patient doses from an x-ray imaging platform with radiation dose–reduction technology, which combined image noise reduction, motion correction, and contrast-dependent temporal averaging with optimized x-ray exposure settings. MATERIALS AND METHODS: In this single-center, retrospective study, cumulative dose-area product inclusive of fluoroscopy, angiography, and 3D acquisitions for all neurovascular procedures performed during a 2-year period on the dose-reduction platform were compared with a reference platform. Key study features were the following: The neurointerventional radiologist could select the targeted dose reduction for each patient with the dose-reduction platform, and the statistical analyses included patient characteristics and the neurointerventional radiologist as covariates. The analyzed outcome measures were cumulative dose (kerma)-area product, fluoroscopy duration, and administered contrast volume. RESULTS: A total of 1238 neurointerventional cases were included, of which 914 and 324 were performed on the reference and dose-reduction platforms, respectively. Over all diagnostic and neurointerventional procedures, the cumulative dose-area product was significantly reduced by 53.2% (mean reduction, 160.3 Gy × cm(2); P < .0001), fluoroscopy duration was marginally significantly increased (mean increase, 5.2 minutes; P = .0491), and contrast volume was nonsignificantly increased (mean increase, 15.3 mL; P = .1616) with the dose-reduction platform. CONCLUSIONS: A significant reduction in patient radiation dose is achievable during neurovascular procedures by using dose-reduction technology with a minimal impact on workflow.

Background Flow diverter (FD) malapposition is associated with stroke-related complications. We document the use of self-expanding nitinol stents to remove/reduce the ledge of a FD deployed for aneurysm treatment. Methods We identified five patients who were treated with the Pipeline embolization device (PED) in conjunction with a Neuroform EZ stent for inadequate wall apposition of the ends of the FD at our institution between May 2014 and July 2015. Among other parameters, angiographic results, cone-beam computed tomography assessment of wall apposition and patient clinical outcome were evaluated. Results Incomplete device end apposition was seen in three cases, and precarious positioning of the distal end of the PED over the aneurysm neck was seen in two cases. In all five cases, successful treatment with good wall apposition and proper pinning of the PED distal edge was achieved using an additional Neuroform EZ stent. Appropriate aneurysm neck coverage and flow stagnation was seen in all cases. The combination of high radial outward force and open-cell design permits the Neuroform EZ stent to jail the malappositioned edges of the FD while maintaining good vessel-wall apposition itself and prevent migration of the PED. Short-term follow-up angiography showed device patency and complete aneurysm obliteration in all cases. Conclusions Preliminary results of this small case series suggest that the Neuroform EZ stent allows for effective treatment of FD malapposition in selected patients amenable for this endovascular approach. Long-term and larger cohort studies are needed to validate these results.

Background Intracranial aneurysms (IAs) associated with dural arteriovenous shunts (DAVSs) are rare and infrequently discussed in conjunction with brain arteriovenous malformation (bAVM). We studied at two cerebrovascular centers IAs and associated DAVSs. Patients and methods Between 2005 and 2018, 103 subjects with DAVSs were retrospectively analyzed for the presence of remote IAs. Demographics, clinical symptoms, aneurysm and DAVS location, treatment and clinical outcomes were studied. Pertinent literature on IAs associated with DAVSs was also reviewed. Results In our study the incidence of remote IAs associated with DAVSs was 13.6%. Fourteen patients with Borden type DAVS I-III (m/f 1:1; age: 32–84 yrs; mean: 60 yrs) harbored a total of 18 aneurysms. Five patients had multiple aneurysms. High cervical DAVSs were found in 4 subjects. Eleven patients presented with history of a high blood pressure. Most common symptoms were headaches and tinnitus (n= 6) followed by subarachnoid hemorrhage (SAH) and or intracranial hemorrhage (ICH) in 6 patients and cranial nerve deficit in one patient. Treatment was commenced in a staged fashion initially addressing the symptomatic lesion. Eleven DAVSs and 9 aneurysms were successfully treated endovascularly while one patient underwent surgery for his DAVS and 2 aneurysms were clipped. A total of 6 tiny unruptured aneurysms and one high-cervical DAVS as well as a frontal slow-flow DAVS did not receive any treatment for various reasons. Seven aneurysms were treated with and without stent-assisted coil embolization and one pericallosal artery aneurysm was successfully treated with a flow diverter. There were no treatment related complications. Follow-up angiography showed an untreated low-flow DAVS shrank in size and another DAVS spontaneously resolved. During clinical follow-up period, 11 subjects presented with a mRS score of 0 while 3 subjects had a mRS of 1. Literature review included a total of 28 cases with 41 aneurysms. Data were compared with our own findings. Conclusions Since remote IAs were not flow-related but showed typical distribution, DAVSs may share the pathomechanism with IAs. Most IAs were located in the anterior circulation and half of the DAVS were found in the anterior cranial fossa. Aneurysm rupture was more common than a bleed from the DAVS, especially when multiple IAs were present. Carefully planned and executed EVT and surgery was effective for this complex population with an excellent long-term clinical outcome. Disclosures W. Htun: None. W. Wang: None. M. Howk: None. C. David: None. I. Choi: None. A. Wakhloo: None.

Background CT perfusion (CTP) and diffusion or perfusion MRI might assist patient selection for endovascular thrombectomy. We aimed to establish whether imaging assessments of irreversibly injured ischaemic core and potentially salvageable penumbra volumes were associated with functional outcome and whether they interacted with the treatment effect of endovascular thrombectomy on functional outcome.Methods In this systematic review and meta-analysis, the HERMES collaboration pooled patient-level data from all randomised controlled trials that compared endovascular thrombectomy (predominantly using stent retrievers) with standard medical therapy in patients with anterior circulation ischaemic stroke, published in PubMed from Jan 1,2010, to May 31, 2017. The primary endpoint was functional outcome, assessed by the modified Rankin Scale (mRS) at 90 days after stroke. Ischaemic core was estimated, before treatment with either endovascular thrombectomy or standard medical therapy, by CTP as relative cerebral blood flow less than 30% of normal brain blood flow or by MRI as an apparent diffusion coefficient less than 620 mu m(2)/s. Critically hypoperfused tissue was estimated as the volume of tissue with a CTP time to maximum longer than 6 s. Mismatch volume (ie, the estimated penumbral volume) was calculated as critically hypoperfused tissue volume minus ischaemic core volume. The association of ischaemic core and penumbral volumes with 90-day mRS score was analysed with multivariable logistic regression (functional independence, defined as mRS score 0-2) and ordinal logistic regression (functional improvement by at least one mRS category) in all patients and in a subset of those with more than 50% endovascular reperfusion, adjusted for baseline prognostic variables. The meta-analysis was prospectively designed by the HERMES executive committee, but not registered.Findings We identified seven studies with 1764 patients, all of which were included in the meta-analysis. CTP was available and assessable for 591 (34%) patients and diffusion MRI for 309 (18%) patients. Functional independence was worse in patients who had CTP versus those who had diffusion MRI, after adjustment for ischaemic core volume (odds ratio [OR] 0.47 [95% CI 0.30-0.72], p=0.0007), so the imaging modalities were not pooled. Increasing ischaemic core volume was associated with reduced likelihood of functional independence (CTP OR 0.77 [0.69-0.86] per 10 mL, p(interaction)=0.29; diffusion MRI OR 0.87 [0.81-0.94] per 10 mL, p(interaction)=0.94). Mismatch volume, examined only in the CTP group because of the small numbers of patients who had perfusion MRI, was not associated with either functional independence or functional improvement. In patients with CTP with more than 50% endovascular reperfusion (n=186), age, ischaemic core volume, and imaging-to-reperfusion time were independently associated with functional improvement. Risk of bias between studies was generally low.Interpretation Estimated ischaemic core volume was independently associated with functional independence and functional improvement but did not modify the treatment benefit of endovascular thrombectomy over standard medical therapy for improved functional outcome. Combining ischaemic core volume with age and expected imagingto-reperfusion time will improve assessment of prognosis and might inform endovascular thrombectomy treatment decisions. Copyright (C) 2018 Elsevier Ltd. All rights reserved.

ObjectiveEvaluation of the safety and efficacy of the Pipeline embolization device (PED) when used as second-line treatment for recurrent or residual, pretreated ruptured and unruptured intracranial aneurysms (IAs).MethodsRetrospective review of our database to include all patients who were treated with a PED for recurrent or residual IAs following surgical clipping or coiling. We evaluated neurological outcome and angiograms at discharge, 6- and 12-months’ follow-up and assessed intimal hyperplasia at follow-up.ResultsTwenty-four patients met our inclusion criteria. Most IAs were located in the anterior circulation (n=21). No change of preprocedure modified Rankin Scale score was seen at discharge or at any scheduled follow-up. Complete or near-complete aneurysm occlusion on 6- and 12-month angiograms was seen in 94.4% (17/18 cases) and 93.3% (14/15 cases), respectively. Complete or near-complete occlusion was seen in 100% of previously ruptured and 85.7% (6/7 cases) and 83.3% (5/6 cases) of previously unruptured cases at the 6- and 12-months’ follow-up, respectively. One case of moderate intimal hyperplasia was observed at 6 months and decreased to mild at the 12-months’ follow-up. No difference in device performance was observed among pretreated unruptured or ruptured IAs.ConclusionsTreatment of recurrent or residual IAs with a PED after previous coiling or clipping is feasible and safe. There is no difference in device performance between ruptured or unruptured IAs.

Background A new generation of highly navigable large-bore aspiration catheters and retriever devices for intracranial mechanical thrombectomy has markedly improved recanalization rates, time and clinical outcomes. We report collected clinical data utilizing a new technique based on combined large lumen aspiration catheter and partially resheathed stent retriever (ARTS: Aspiration (catheter)–(stent) Retriever Technique for Stroke). This technique is applied, especially in presence of bulky/rubbery emboli, when resistance is felt while retracting the stent retriever; at that point the entire assembly is locked and removed in-toto under continuous aspiration with additional flow arrest. Methods A retrospective data analysis was performed to identify patients with large cerebral artery acute ischemic stroke treated with ARTS. The study was conducted between August 2013 and February 2015 at a single high volume stroke center. Procedural and clinical data were captured for analysis. Results Forty-two patients (median age 66 years) met inclusion criteria for this study. The ARTS was successful in achieving Thrombolysis in Cerebral Infarction (TICI) ≥2b revascularization in 97.6% of cases (TICI 2b = 18 patients, TICI 3 = 23 patients). Patients’ median National Institutes of Health Stroke Scale score at admission was 18 (6–40). A 3-month follow-up modified Rankin Scale value of 0–2 was achieved in 65.7% of the successfully treated patients (average 2.4). Two patients (4.8%) developed symptomatic intraparenchymal hemorrhages. Six procedure unrelated deaths were observed. Conclusions We found that ARTS is a fast, safe and effective method for endovascular recanalization of large vessel occlusions presenting within the context of acute ischemic stroke.

Background To evaluate the feasibility and efficacy of the pipeline embolization device in the treatment of unruptured intracranial mirror segment aneurysms. Methods Out of a total of 338 subjects, 14 were identified harboring a total of 32 internal carotid artery mirror segment aneurysms that were treated with the pipeline embolization device and were consecutively enrolled into our study. We collected data on patient demographics, modified Rankin scale (mRS) at admission, aneurysm characteristics, clinical outcome at discharge, 3–9 and at 12–18 months as well as angiography results at follow-up. Results Patients’ mean age was 52.9 years; baseline mRS was 0 in all subjects. Pipeline embolization device placement was successful in all cases. Post-treatment mRS remained 0 in 13/14 patients. One patient experienced a small intraparenchymal hemorrhage and subarachnoid hemorrhage, associated with a frontoparietal infarction resulting in right upper extremity weakness and aphasia (post-treatment mRS 3). His mRS evaluation remained stable at the 3–9-month follow-up. Three to 9-month follow-up angiography (13/14 subjects) showed complete aneurysm occlusion in 24/30 aneurysms (80%), near complete and partial occlusion in three of 30 (10%) aneurysms each. At the 9-month follow-up, one patient experienced a complete occlusion of the anterior temporal artery branch but did not present with any clinical deficits. No mRS changes were encountered over a median 6-month follow-up period. Mid-term follow-up angiography (12–18 months) available in eight of 14 subjects showed complete aneurysm occlusion in all patients. Mild intimal hyperplasia was observed in one patient. Conclusions Flow diversion technology can be used for the treatment of unruptured mirror segment aneurysms in selected patients.

Introduction Pipeline Embolization Device (PED) has proven to be an effective treatment for intracranial aneurysm with high rates of long-term complete occlusion.1,2 However, some aneurysms either do not achieve complete occlusion3–6 or heal in a delayed fashion7 during which the aneurysm is not protected from rupture. Recent scientific reports from animal models show that poor wall apposition of PED devices can lead to delayed occlusion of aneurysms.8,9 The purpose of this study was to compare the mid-term occlusion rates with or without balloon angioplasty (BA) after PED delivery. Materials and methods From October 2011 to September 2016 all consecutive patients treated with a PED and with an available angiographic follow-up performed between 6 and 24 months were included in this study. BA was performed at the operator’s discretion based on imaging findings. Aneurysms with previous history of stenting or cases where a non flow-diverter stent was associated with the PED were excluded from analysis. Clinical presentations, technical details, intra- and perioperative complications, and clinical and angiographic outcomes were recorded in a prospectively maintained database. Results 158 aneurysms were included and angioplasty was performed in 49% of cases. Average follow-up interval was 12 months for both groups (p=0.6). Patients’ demographics and aneurysm characteristics were not different between the two groups (table 1). The number of PED per case was slightly greater in the control group. Complete occlusion rate was significantly higher in the angioplasty group (88%) than in the control group (73%); p=0.017. No BA related hemorrhagic complication was reported. Angioplasty was not associated with a more frequent use of anti GPIIb/IIIa inhibitors (p=0.2), a marker of intra-operative thrombotic event. No increase in baseline mRS score was found during follow-up in the BA group. Conclusions Balloon angioplasty appears to be a safe technique to improve the midterm angiographic outcome after Pipeline Embolization Device treatment. References Becske, et al. Neurosurgery 2017. Brinjikji, et al. Stroke 2013. Shapiro, et al. Journal of Neurosurgery 2016. Brasiliense, et al. WNEU 2017. Adeeb, et al. AJNR 2017. Gressot, et al. WNEU 2016. Walcott, et al. JAMA Neurol 2016. King, et al. JNIS 2017. Rouchaud al. AJNR 2016. Disclosures J. Caroff: None. K. de Macedo Rodrigues: None. M. Howk: None. D. Rex: None. F. Massari: None. A. Kuhn: None. A. Wakhloo: 1; C; Philips Med (research and equipment support and MAB); Medtronic Consultant: Stryker Neurovascular. 2; C; Stryker Neurovascular. 3; C; Harvard Postgraduate Course; Baptist Health, Jacksonville, FL. 4; C; EpiEP; Neural Analytics; 4L Analytics; InNeuroCo. 5; C; Co-founder, CMO and Board member InNeuroCo. R. King: None. M. Gounis: 1; C; Medtronic Neurovascular, Stryker Neurovascular, Cerenovus Neurovascular. 2; C; Cerenovus Neurovascular, Medtronic Neurovascular, Phenox, Stryker Neurovascular. A. Puri: 1; C; Medtronic Neurovascular, Stryker Neurovascular. 2; C; Cerenovus Neurovascular, Medtronic Neurovascular, Stryker Neurovascular.

BACKGROUND: General anaesthesia (GA) during endovascular thrombectomy has been associated with worse patient outcomes in observational studies compared with patients treated without GA. We assessed functional outcome in ischaemic stroke patients with large vessel anterior circulation occlusion undergoing endovascular thrombectomy under GA, versus thrombectomy not under GA (with or without sedation) versus standard care (ie, no thrombectomy), stratified by the use of GA versus standard care.METHODS: For this meta-analysis, patient-level data were pooled from all patients included in randomised trials in PuMed published between Jan 1, 2010, and May 31, 2017, that compared endovascular thrombectomy predominantly done with stent retrievers with standard care in anterior circulation ischaemic stroke patients (HERMES Collaboration). The primary outcome was functional outcome assessed by ordinal analysis of the modified Rankin scale (mRS) at 90 days in the GA and non-GA subgroups of patients treated with endovascular therapy versus those patients treated with standard care, adjusted for baseline prognostic variables. To account for between-trial variance we used mixed-effects modelling with a random effect for trials incorporated in all models. Bias was assessed using the Cochrane method. The meta-analysis was prospectively designed, but not registered.FINDINGS: Seven trials were identified by our search; of 1764 patients included in these trials, 871 were allocated to endovascular thrombectomy and 893 were assigned standard care. After exclusion of 74 patients (72 did not undergo the procedure and two had missing data on anaesthetic strategy), 236 (30%) of 797 patients who had endovascular procedures were treated under GA. At baseline, patients receiving GA were younger and had a shorter delay between stroke onset and randomisation but they had similar pre-treatment clinical severity compared with patients who did not have GA. Endovascular thrombectomy improved functional outcome at 3 months both in patients who had GA (adjusted common odds ratio (cOR) 1·52, 95% CI 1·09-2·11, p=0·014) and in those who did not have GA (adjusted cOR 2·33, 95% CI 1·75-3·10, pINTERPRETATION: Worse outcomes after endovascular thrombectomy were associated with GA, after adjustment for baseline prognostic variables. These data support avoidance of GA whenever possible. The procedure did, however, remain effective versus standard care in patients treated under GA, indicating that treatment should not be withheld in those who require anaesthesia for medical reasons.FUNDING: Medtronic.

BackgroundDissecting aneurysms located along the distal segments of the posterior inferior cerebellar artery (PICA) are extremely rare, accounting for only 0.5–0.7% of all intracranial aneurysms. Treatment of these aneurysms is challenging, both surgically and endovascularly. We present our preliminary experience and clinical data utilizing Onyx as an embolization agent in the treatment of these lesions with proximal parent artery preservation.Methods7 consecutive ruptured peripheral PICA aneurysms, in 7 patients, were treated with superselective Onyx embolization at our institutions. According to the anatomical classification of Lister et al, these aneurysms were located in the lateral medullary segment (n=1), tonsillomedullary segment (n=1), and the telovelotonsillary segment (n=5) of the PICA. Technical feasibility, procedure related complications, angiographic results, follow-up diagnostic imaging, and clinical outcome were evaluated.ResultsIn all cases, endovascular treatment was successful, with complete occlusion of the aneurysm with proximal parent artery preservation at the final postprocedural angiogram. Procedure related complications were not observed. One patient with a poor clinical condition at admission died during the initial hospital stay due to extensive subarachnoid and intraventricular hemorrhage. No rebleeding or recanalization was noted during follow-up. Two patients had a residual moderate to severe disability at follow-up. Favorable outcomes, with no or mild disability, were observed in four of the surviving patients.ConclusionsAngiographic, diagnostic imaging, and clinical results of our small series indicate that Onyx embolization of dissecting distal PICA aneurysms with parent artery preservation is an effective option with acceptable morbidity and mortality rate, in those cases in which surgical clipping or endovascular coiling of the aneurysmal sac is not suitable.

Introduction Recent meta-analysis of randomized clinical trials has shown that endovascular intervention yields higher rates of revascularization and superior functional outcomes as compared to standard medical therapy in the setting of emergent large vessel occlusion causing stroke. However, there remained approximately 20% patients in whom successful revascularization (mTICI score, 2b or 3) was not achieved after stent-retriever thrombectomy [1, 2]. Revascularization achieved with thrombectomy devices depends in part upon the integration of the thrombus material into the retrieval device. The histologic composition and mechanical properties of thrombi are key determinants of effective thrombus-device interaction. We hypothesize that calcified and fibrin-rich thrombi are stiffer than erythrocyte-rich thrombi; therefore, they may serve as the challenging thrombus models to evaluate thrombus-device interactions, and further aid the design and development of future generations of stent retrievers. The goal of this study is to 1) characterization of thromboemboli retrieved from patients with AIS, and 2) development of thrombus analogs with histologic and mechanical characteristics similar to those of challenging clinical thrombi for thrombectomy device testing. Materials and methods Thrombi were retrieved from patients with AIS using stent retriever devices. Several technical metrics of the thrombectomy procedure such as number of pass attempts and occurrence of embolic complication were collected. Fifty clinical thrombi collected from twenty nine AIS patients underwent histologic analysis, and nine clinical thrombi were subjected to dynamic mechanical analysis (DMA). Thrombus histology was determined by staining specimens for erythrocytes and fibrin content using the Martius Scarlet Blue technique and performing computerized segmentation and quantitative analysis. During the DMA tests, thrombus stiffness was defined as a function of stress variation over strain. The average stress variation at low strain (E1: 0 to 75% strain) and high strain (E2: 75 to 100% strain) was recorded. The results generated from the clinical samples were used to determine the key components of the challenging thrombus analogs, calcium apatite-rich and fibrin-rich thrombus analogs. Results Of the twenty nine AIS cases analyzed, fifteen cases required multiple pass attempts. The average histologic composition of the clinical thrombi obtained from cases with more than 1 thrombectomy pass was 26% erythrocyte, 54% fibrin, and 20% mixed, whereas the average histologic composition of all the fifty clinical thrombi analyzed was 33% erythrocyte, 47% fibrin, and 20% mixed. The DMA results demonstrated that the stiffness of the challenging clinical thrombi (E1: 0.00011±0.000076MPa, E2: 0.015±0.0083MPa) was similar to that of the fibrin-rich thrombus analogs (E1: 0.00013±0.000002MPa, E2: 0.011±0.0007MPa). Compared to the fibrin-rich thrombus analogs, addition of calcium apatite increased the stiffness of the thrombus analogs by approximately 5 times. Conclusion Thrombus analogs with mechanical characteristics similar to those of challenging clinical thrombi were successfully developed. The calcium apatite thrombus analog was found to be stiffer than the fibrin-rich thrombus analog. References . Saver JL et al: Stent-retriever thrombectomy after intravenous t-PA vs. t-PA alone in stroke. N Engl J Med 2015, 372(24):2285–2295. . Dorn F et al: Endovascular treatment of acute intracerebral artery occlusions with the solitaire stent: single-centre experience with 108 recanalization procedures. Cerebrovasc Dis 2012, 34(1):70–77. Disclosures: J. Chueh: None. J. Litchman: None. R. Arslanian: None. S. Carniato: 5; C; Principal Preclinical Research Associate at Stryker Neurovascular. D. Rex: None. M. Howk: None. M. Gounis: 1; C; research grant supported by Stryker Neurovascular. 2; C; consultant for Stryker Neurovascular. A. Puri: 1; C; research grant suppported by Stryker Neurovascular. 2; C; consultant for Stryker Neurovascular.

The endovascular management of acute ischemic stroke (AIS) due to emergency large vessel occlusion (ELVO) has become the standard of care after the recent publication of landmark randomized, controlled trials. Mechanical thrombectomy, in addition to intravenous thrombolysis (within 4.5 hours when eligible), is now part of the algorithm of the standard of care when treating AIS in patients with ELVO in the anterior circulation up to six hours after symptom onset. A newly introduced device, the Arc™ intracranial support catheter (Medtronic, Irvine, USA), is specifically designed for the introduction of neurointerventional devices into the cerebral vasculature and facilitates the delivery of microcatheters into smaller, more distal intracranial vessels. This technical report describes the use of the Arc™ intracranial support catheter in the setting of AIS.

ObjectiveTo evaluate the safety and efficacy of the ‘Baby Trevo’ (Trevo XP ProVue 3×20 mm Retriever) stent retriever for large vessel occlusions (LVOs) in acute ischemic stroke (AIS).Materials and methodsWe retrospectively analyzed our stroke database and included all patients treated with the Baby Trevo for distal LVOs in AIS. Patient gender, mean age, vascular risk factors, National Institutes of Health Stroke Scale (NIHSS) score at presentation, and modified Rankin Scale (mRS) score at baseline and 90-day follow-up were documented. Reperfusion rates for the vessels treated were recorded using the Thrombolysis in Cerebral Infarction (TICI) classification. Occurrence of vasospasm and new or evolving infarcts in the treated vascular territory was documented.ResultsThirty-five subjects with a mean NIHSS score of 18 were included. The Baby Trevo device was used in 38 branches of the anterior and posterior circulations. TICI 2b/3 blood flow was restored after one single pass in 20/38 (52.6%) and after two or three passes in 11 vessels. The remaining vessels required either more than three passes, showed less than a TICI 2b/3 reperfusion (n=3), or demonstrated failure to retrieve the clot (n=4). TICI 2b/3 reperfusion was achieved in 30 patients (85.7%). No vessel injuries, rupture, or significant vasospasm were seen. Overall, a mRS score of ≤2 was seen in 56.5% of the subjects successfully treated with the Baby Trevo at 90 days and in 81.3% of surviving patients; seven patients died (20%).ConclusionsOur preliminary data suggest that the ‘Baby Trevo’ achieves a high recanalization rate without any significant risk. Larger cohort studies are needed to validate the clinical benefit.

BackgroundDissecting aneurysms of the vertebral artery (VA) are difficult to treat using current surgical and endovascular techniques.ObjectiveTo analyze retrospectively the efficacy and safety of flow diverters in the treatment of dissecting aneurysms of the vertebral artery.MethodsWe identified six patients with six unruptured VA dissecting aneurysms either arising from the V4 or V3–V4 junction that were treated with the Pipeline embolization device (PED) at our institution between July 2012 and February 2015. Among other parameters, technical feasibility of the procedure, procedure-related complications, angiographic results, and clinical outcome were evaluated.ResultsPED placement was achieved in all cases and immediate angiography follow-up demonstrated intra-aneurysmal contrast stasis with parent artery preservation. A temporary episode of dysarthria was noted in one patient. Major procedure-related complications were not observed. The 6-month follow-up (n=6) demonstrated complete/near-complete aneurysm obliteration in five patients and partial obliteration in one. At the 1-year follow-up (n=5) stable complete aneurysm occlusion was seen in two patients. Two cases showed progression from near complete occlusion and partial occlusion at 6 months to complete occlusion and near complete occlusion. One cases showed unchanged near complete occlusion. No aneurysmal bleeding, in-stent stenosis or thromboembolic complication was seen. National Institutes of Health Stroke Scale and modified Rankin scale scores remained unchanged from admission to discharge.ConclusionsOur preliminary experience with the use of PED for the treatment of intradural VA dissecting aneurysms shows promising short-term results, making this technique a feasible and safe treatment option in patients suitable for this approach. However, long-term and larger cohort studies are needed to validate these results.

Flow diversion is being increasingly used to treat cerebral aneurysms. We present our experience using these stents to treat aneurysms distal to the circle of Willis with parent arteries smaller than 2.5 mm. Aneurysms treated with a Pipeline™ Embolization Device in vessels less than 2.5 mm between June 2012 and August 2014 were included. We evaluated risk factors, family history of aneurysms, aneurysm characteristics, National Institute of Health Stroke Scale (NIHSS), and modified Rankin scale (mRS) on admission and angiography and clinical outcome at discharge, 6 months, and 1 year. We included seven patients with a mean age of 65 years. The parent vessel size ranged from 1.5 to 2.3 mm; mean 1.9 mm. Location of the aneurysms was as follows: two aneurysms centered along the pericallosal artery (one left, one right), one on the right angular artery, one aneurysm at the anterior communicating artery (ACom), one at the ACom-right A2 anterior cerebral artery (ACA), one at the lenticulostriate artery, and one at the A1-A2 ACA artery. Aneurysms ranged from 1 to 12 mm in diameter. All aneurysms were treated with a single Pipeline™ Embolization Device (PED). No peri- or post-procedural complications or mortality occurred. The patients were discharged with no change in NIHSS or mRS score. Angiographic follow-up was available in six patients. Angiography showed complete aneurysm occlusion in all. NIHSS and mRS remained unchanged at follow-up. Our preliminary results show that flow diversion technology is an effective and safe therapy for aneurysms located on small cerebral arteries. Larger studies with long-term follow-up are needed to validate our promising results.

Isolated middle cerebral artery dissection is a rare clinical entity, with descriptions limited to a few case reports and case series. Symptomatic dissection in the anterior circulation can present as an ischemic stroke in a young population; however, it is rarely associated with subarachnoid hemorrhage. We describe a young patient who presented with acute headache from a subarachnoid hemorrhage that was ultimately determined to be due to a vascular dissection in the middle cerebral artery. The initial angiogram showed vascular irregularities in this area with stenosis. Repeat imaging 4 days after presentation identified a pseudoaneurysm proximal to the stenosis. The patient was successfully treated with a self-expanding nitinol stent and followed up with serial angiography during postoperative recovery in the hospital; additional angiograms were performed approximately 1 and 6 months after treatment. Serial angiograms demonstrated incremental healing of the dissection. The patient was discharged and remains neurologically intact at the 6-month follow-up.

Background/objective Pericallosal artery aneurysm treatment is challenging using traditional endovascular techniques due to the small caliber of the parent vessel and distal access. Wide neck and bifurcation aneurysms in this location require manipulation with 2 catheters for balloon assisted or stent assisted coil embolization with increased friction and limited margin for error. We demonstrate the feasibility, efficacy and safety of endovascular treatment of pericallosal artery aneurysm using flow diversion technology. Methods We performed a retrospective review of our institutional database from July 2013 through July 2015. Five subjects with a pericallosal artery aneurysm that was treated with the Pipeline embolization device (PED) were identified. We evaluated for technical feasibility, presence of procedural complication, angiographic results, and clinical outcome. Results Successful placement of a single PED across the neck of the aneurysm was achieved in all cases. No procedure-related complications were encountered. A 6 month follow-up angiogram was available for 4 patients and a 12 month follow-up angiogram was available for 2 patients. Four out of 5 patients had complete aneurysm occlusion demonstrated, 3 of them were demonstrated at the 6 month follow-up and 1 at 12 month follow-up. The subject for which occlusion was demonstrated at the 12 month follow-up did not have a 6 month angiogram available for review. One patient had persistent aneurysm filling at 6 month, with a 50–60% decrease in aneurysm size. There were 2 cases of narrowing of at the origin of an artery that had been coved by the PED, without flow limitation or clinical consequences. There was no evidence of in-stent stenosis or intimal hyperplasia. No thromboembolic or hemorrhagic complication was seen. Modified Rankin scale scores remained unchanged from baseline. Conclusions Our preliminary results support the use of flow diverter stent for treatment of aneurysms of the pericallosal artery with high rate of aneurysm occlusion, without evidence of increased procedural complication or short-term morbidity. A long-term and larger cohort study is desirable to validate our results. Disclosures K. de Macedo Rodrigues: None. A. Kuhn: None. T. Tamura: None. G. Dabus: None. P. Kan: 2; C; PK is a consultant for Stryker Neurovascular, Covidien, and MicroVention. M. Marosfoi: None. J. Lozano: None. M. Howk: None. M. Perras: None. C. Brooks: None. D. Rex: None. F. Massari: None. M. Gounis: 1; C; NIH, Medtronic Neurovascular, Microvention/Terumo, Cerevasc LLC, Gentuity, Codman Neurovascular, Philips Healthcare, Stryker Neurovascular, Tay Sachs Foundation, and InNeuroCo Inc. 2; C; Codman Neurovascular and Stryker Neurovascular. 4; C; InNeuroCo Inc. A. Wakhloo: 1; C; NIH, Philips Healthcare, Wyss Institute. 2; C; Codman Neurovascular and Stryker Neurovascular. 4; C; co-founder of InNeuroCo Inc. and major stockholder; stocks in EpiEB and Pulsar Medical. 6; C; speaker: Harvard Postgraduate Course, Miami Cardiovascular Institute. A. Puri: 1; C; Stryker Neurovascular and Covidien. 2; C; Codman Neurovascular, Stryker Neurovascular and Covidien. 4; C; InNeuroCo Inc. 6; C; speaker: Miami Cardiovascular Institute.

Objective The efficacy of stent-retrievers in achieving recanalization in the setting of acute ischemic stroke (AIS) secondary to an emergency large vessel occlusion (ELVO) has now been conclusively proven in several randomized clinical trials. However, in a small subset of these patients recanalization may not be achieved by means of mechanical thrombectomy with stent-retrievers and/or thromboaspiration with large bore catheters. In selected cases of this type of recalcitrant occlusion, acute intracranial stenting may be safe and effective as a last and final effort to achieve flow restoration and improve recanalization rates with good clinical outcomes (Modified Ranking Scale (mRS) ≤2). Methods Retrospective analysis of 7 patients who underwent endovascular treatment of ELVO between January 2012 and April 2016 at a single tertiary care center with acute intracranial stenting for a vessel occlusion recalcitrant to recanalization by means of standard mechanical thrombectomy and/or thromboaspiration techniques. Results Six males and a female with median baseline National Institutes of Health Stroke Scale (NIHSS) score of 20 (range 18–29) were included in this study. Three occlusive lesions were located from the internal carotid artery (ICA) terminus to the M1, 2 lesions were distal M1 occlusions, 1 lesion was a distal M1 occlusion that spanned the superior and inferior M2 divisions, and 1 lesion was at the distal basilar extending to the bilateral P1 segments. The median number of attempted yet unsuccessful mechanical thrombectomies before considering acute intracranial stenting was 4. One procedure included balloon angioplasty prior to stenting, two procedures included mechanical thromboaspiration in addition to mechanical thrombectomy with stent-retrievers, and one of the procedures included intra-arterial TPA and thromboaspiration in between stent-retriever attempts. Two cases required Y-stenting due to recalcitrant clot burden at the bifurcation of a large vessel (MCA bifurcation into superior and inferior M2 divisions, and distal basilar artery into bilateral P1 segments; mRS at 30 days was 0 and 1, respectively). The average time from last seen well to recanalization with acute intracranial stenting was 317 min +187 min. Recanalization rates were AOL 2 in 85% (6/7) and AOL 3 in 15% of cases (1/7). Reperfusion rates were TICI 3 in one case, TICI 2 B in 4 and TICI 2 A in 2 cases. Supraselective intra-arterial eptafibatide was used either before or immediately after stenting in 42% of cases (3/7); daily aspirin after stenting was used in all cases (7/7); and a combination of aspirin and clopidogrel was used in 71% of cases (5/7). There were two deaths: One as a result of hemorrhagic transformation of the ischemic stroke with subsequent malignant edema and the second one due to progression of stroke and withdrawal of care at the request of the family. Modified Rankin Scale mRS ≤2 at 30 days was achieved in 42% of the cases (3/7). Conclusion Initial results suggest that acute intracranial stenting may be beneficial in a subset of patients who present with an ELVO and who have failed recanalization by means of mechanical thrombectomy with stent-retrievers and/or thromboaspiration with large bore intracranial catheters. Disclosures J. Lozano: None. M. Howk: None. A. Kuhn: None. F. Massari: None. K. de Macedo Rodrigues: None. C. Brooks: None. M. Perras: None. M. Gounis: 1; C; NIH, Medtronic Neurovascular, Microvention/Terumo, Cerevasc LLC, Gentuity, Codman Neurovascular, Phillips Healthcare, Stryker Neurovascular, Tay Sachs Foundation, InNeuroCo Inc. 2; C; Codman Neurovascular, Stryker Neurovascular. 4; C; InNeuroCo Inc. D. Rex: None. A. Wakhloo: 1; C; NIH, Phillips Healthcare, Wyss Institute. 2; C; Codman Neurovascular, Stryker Neurovascular. 3; C; Harvard Postgraduate Course. 4; C; InNeuroCo Inc., EpiEb, Pulsar Medical. A. Puri: 1; C; Stryker Neurovascular, Covidien. 2; C; Codman Neurovascular, Stryker Neurovascular, Covidien. 3; C; Miami Cardiovascular Institute. 4; C; InNeuroCo Inc.

Purpose Flow diverter malapposition as a technical complication with the use of the pipeline embolization device has been described and maybe is associated with delayed ischemic events or potentially delayed life-threatening aneurysm rupture. We describe our endovascular techniques for manipulation of flow diverters in order to achieve proper vessel wall apposition. Materials and methods We retrospectively analyzed our flow diverter database and included all patients in whom malapposition of the device was detected on follow-up angiography immediately after device deployment. We then evaluated feasibility and technical success of different endovascular approaches aimed to correct the inadequate vessel wall apposition. Successful endovascular techniques for manipulation of the device included use of wires, catheters and additional devices. Final confirmation of flow diverter wall apposition prior to completion of the intervention was performed using 3D multi-planar cone-beam CT reconstruction images. Results We identified 5 successful endovascular techniques for better flow diverter wall apposition: 1) Use of a wire with a J, pigtail or S-shaped tip passed through the device, 2) Manipulation with a microcatheter, which can be used to press the PED against the vessel wall, 3) Balloon angioplasty of the malapposed segment, 4) Manipulation with an intermediate catheter, which can be used at the proximal edge or within the flow diverter to push the PED against the vessel wall, 5) Placement of another flow diverter within the previously placed FD to better oppose the ends and 6) Placement of an open-cell stent in telescopic fashion across the malapposed portion of the PED (proximal or distal edge). The Neuroform stent with its high outward radial force is an excellent adjunct treatment option to anchor the malapposed flow diverter against the vessel wall while permitting perforator patency. Conclusion Flow diverter malapposition can be addressed successfully during the interventional procedure using a variety of techniques. This may prevent devastating delayed complications. Disclosures A. Kuhn: None. K. de Macedo Rodrigues: None. M. Gounis: 1; C; NIH, Medtronic Neurovascular, Microvention/Terumo, Cerevasc LLC, Gentuity, Codman Neurovascular, Philips Healthcare, Stryker Neurovascular, Tay Sachs Foundation, and InNeuroCo Inc. 2; C; Codman Neurovascular and Stryker Neurovascular. 4; C; InNeuroCo Inc. P. Kan: 2; C; Stryker Neurovascular, Covidien, and MicroVention. M. Marosfoi: None. J. Lozano: None. M. Perras: None. C. Brooks: None. M. Howk: None. D. Rex: None. F. Massari: None. A. Wakhloo: 1; C; NIH, Philips Healthcare, Wyss Institute. 2; C; Codman Neurovascular and Stryker Neurovascular. 3; C; Harvard Postgraduate Course, Miami Cardiovascular Institute. 4; C; InNeuroCo Inc, EpiEB and Pulsar Medical. A. Puri: 1; C; Stryker Neurovascular and Covidien. 2; C; Codman Neurovascular, Stryker Neurovascular and Covidien. 3; C; Miami Cardiovascular Institute. 4; C; InNeuroCo Inc.

Purpose To evaluate safety and efficacy of the pipeline embolization device (PED) in patients of different age groups and with incidentally found or recanalised (previously coiled or clipped) aneurysms. Materials and methods All patients with an incidentally found or recanalised aneurysm and treated with the PED at our institution between 2011 and 2016 were included. We then divided the patient cohort into three age groups representing young (Y, ≤45 years), middle age (M, 46- Results We included 140 patients harboring 164 aneurysms with 20 patients in the young age group, 88 in the middle age and 32 in the older age group. Male to female ratio was approximately 1:4 overall and interestingly in all age groups as well. The majority of aneurysms were located in the anterior circulation (94.5%) and found incidentally (75%). Twenty-four aneurysms had been previously treated (12 ruptured and 12 unruptured). Smoking, hypertension and dyslipidemia were the most frequently encountered vascular risk factors in all age groups, with smoking being most common in the young, hypertension the most common in the middle age and hypertension/dyslipidemia the most common in the older age group. Median mRS on admission and discharge was 0 for all age groups. The median mRS remained 0 at 6 and 12 month follow-up. Overall mortality and morbidity rate was 2.1% (3/140, M = 2 and O = 1), Complete aneurysm occlusion at 6 and 12 months was seen in 77% (78/101) and 80% (52/65), respectively. Mild intimal hyperplasia was seen in 18 cases total (18%) with 2 cases in the young, 11 in the middle age and 5 in the older age group. Moderate and severe intimal hyperplasia was found in one case each (young and older age group). No retreatment was required. Nine aneurysms (Y = 3, M = 5 and O = 1) which demonstrated near complete occlusion at 6 months showed complete occlusion in 2 cases (M = 2) and stable near complete occlusion in the remaining 7 at the 12 month mark. For aneurysms demonstrating partial occlusion at 6 months (Y = 2, M = 5, O = 3), 12 months follow-up showed progression to complete or near complete occlusion in 1 case each (Y = 1 and M = 1) and stable partial occlusion in 3 cases (M = 3). Available 12 months follow-up for mild intimal hyperplasia detected at 6 months showed resolution in 4 cases (M = 1 and O = 3) and stable mild hyperplasia in 5 cases (Y = 1 and M = 4). One case of moderate intimal hyperplasia at 6 months (young age group) improved to mild hyperplasia at 12 months follow-up. Subanalysis of treatment outcome of incidentally found aneurysms compared to unruptured pretreated or ruptured pretreated aneurysms showed no difference of flow diverter performance between the different aneurysm groups or among the different patient age groups. Conclusion PED placement is feasible and safe in patients of different age groups and with incidental or recanalised aneurysms. Disclosures A. Kuhn: None. J. Lozano: None. K. de Macedo Rodrigues: None. F. Massari: None. A. Wakhloo: 1; C; NIH, Philips Healthcare, Wyss Institute. 2; C; Codman Neurovascular and Stryker Neurovascular. 3; C; Harvard Postgraduate Course, Miami Cardiovascular Institute. 4; C; InNeuroCo Inc, EpiEB and Pulsar Medical. D. Rex: None. M. Gounis: 1; C; NIH, Medtronic Neurovascular, Microvention/Terumo, Cerevasc LLC, Gentuity, Codman Neurovascular, Philips Healthcare, Stryker Neurovascular, Tay Sachs Foundation, and InNeuroCo Inc. 2; C; Codman Neurovascular and Stryker Neurovascular. 4; C; InNeuroCo Inc. M. Marosfoi: None. M. Perras: None. C. Brooks:None. M. Howk: None. A. Puri: 1; C; Stryker Neurovascular and Covidien. 2; C; Codman Neurovascular, Stryker Neurovascular and Covidien. 3; C; Miami Cardiovascular Institute. 4; C; InNeuroCo Inc.

Background The development of a new generation of highly navigable large bore aspiration catheters and retriever devices, dedicated to the revascularization of large intracranial vessel occlusions in the context of acute ischemic stroke (AIS), has improved recanalization rates and time, with significant impact on clinical outcomes. We report a retrospectively collected clinical data utilizing a new recanalization technique based on combined large lumen aspiration catheter and partially resheathed stent retrievers for thrombectomy (ARTS: ACE-Retriever Technique for Stroke). Methods A retrospective data analysis was performed to identify patients with acute ischemic stroke treated at our institution with ARTS for occluded large cerebral vessels recanalization. The study was conducted between July 2013 and October 2014 at a single high volume stroke center. Procedural and clinical data were captured for analysis, including recanalization rate, post-treatment National Institutes of Health Stroke Scale (NIHSS) score, symptomatic intracranial hemorrhage, discharge 90 day modified Rankin Scale (mRS) score, and mortality. Results 40 patients (average age of 64.5 years, range 90–20 years; 24 F:16 M) were found that met the inclusion criteria for this retrospective study. The ARTS was successful in achieving Thrombolysis in Cerebral Infarction (TICI) 2b or 3 revascularization in 97.5% of cases (TICI 2b = 18 pts, TICI 3 = 21 pts). The average time from groin puncture to at least TICI 2b recanalization was 62 min. In patients with successful recanalization, admitted with median National Institutes of Health Stroke Scale (NIHSS) score of 16.7 (6.0–29.0), was observed a value improvement to a median NIHSS score at discharge of 3.4 (0–13.0). In eight patients (20%), the association of a carotid bifurcation severe stenosis/occlusion and intracranial large vessel occlusion (tandem lesions), required a carotid stent deployment along the cervical segment of the internal carotid artery. A 3 month follow-up Modified Rankin Scale (mRS) value of 0–2 was observed in 48.5% of the successfully treated patients (average 2.6). Two patients were lost to follow-up. No procedure related deaths were observed. Conclusions Mechanical thrombectomy utilizing combined 5 MAX ACE aspiration catheter and Stent Retrievers Technique for Stroke treatment (ARTS) is a fast, safe and effective method for endovascular recanalization of large vessel occlusions presenting within the context of AIS. Disclosures F. Massari: None. N. Henninger: None. J. Lozano: None. M. Howk: None. M. Perras: None. C. Brooks: None. M. Gounis: 1; C; NIH, Philips Healthcare, Covidien, Codman, Stryker, Wyss Institute, Tay Sachs Foundation. 2; C; Stryker (fee per hour). A. Wakhloo: 1; C; Philips Medical. 2; C; Stryker. 3; C; Harvard Postgraduate Course, Miami Baptist Vascular Institute. A. Puri: 1; C; Stryker. 2; C; Codman, Covidien.

Introduction/purpose Dissecting aneurysms of the vertebral artery (VA) are difficult to treat using current surgical and endovascular techniques. Currently, there is no consensus on management strategies of dissecting VA aneurysms. The characteristics of flow diverter stents appear to have ideal requirements for the treatment of dissecting VA aneurysms. In this study, we retrospectively analyzed the efficacy and safety of flow diverters in the treatment of such lesions. Materials and methods We identified six patients with six VA dissecting aneurysms either arising from the V4 or V3–V4 junction that were treated with the pipeline embolization device (PED) at our institution from July 2012 to February 2015. Among other parameters, technical feasibility of the procedure, procedure-related complications, angiographic results, and clinical outcome were evaluated. Results Six patients, 3 females and 3 males, with a mean age of 52.8 years (age range 39–63 years) were identified. Vascular risk factors included hypertension (4/6), dyslipidemia (2/6), fibromuscular dysplasia (1/6) and smoking (1/6). The aneurysms were incidental findings in 3 cases, whereas the other 3 patients presented with neurological symptoms such as visual changes, ataxia, facial numbness or vertigo. Diagnostic angiography confirmed the presence of fusiform dissecting aneurysms centered at the V4 segment in 5 cases and at the vertebral V3–V4 junction in one case. PED placement was achieved in all cases and immediate angiography follow-up demonstrated intra-aneurysmal contrast stasis with parent artery preservation. A temporary episode of dysarthria was noted in one patient. Major procedure-related complications were not observed. 6-month follow-up (n = 5) demonstrated complete/near complete aneurysm obliteration in 4 and partial obliteration in 1 patient. At 1-year follow-up (n = 4) stable complete aneurysm occlusion was seen in 2 patients. One patient demonstrated progression from near complete to complete occlusion and the previously noted partial occlusion remained stable. No aneurysmal bleeding, in-stent stenosis or thromboembolic complication was observed. NIHSS and mRS scores remained unchanged from admission to discharge. Conclusion Our preliminary experience with endoluminal reconstruction of intradural dissecting VA aneurysms with the PED confirms this treatment approach to be feasible and safe with good short-term angiographic and clinical outcomes. Long-term and larger cohort studies will need to provide further information on durable aneurysm obliteration in response to hemodynamic intravascular flow changes and the occurrence of delayed hemorrhage and in-stent thrombosis. The promising results obtained so far, however, appear to support the use of flow diverter in the treatment of dissecting intracranial VA aneurysms; especially in circumstances where maintaining parent artery and side branch patency is required. Disclosures A. Kuhn: None. F. Massari: None. J. Lozano: None. S. Hou: None. M. Howk: None. M. Perras: None. C. Brooks: None. P. Kan: None. M. Gounis: 1; C; NIH, Philips Healthcare, Covidien/eV3 Neurovascular, Codman Neurovascular, Stryker Neurovascular, Wyss Institute, Tay Sachs Foundation. 2; C; fee-per-hour consultation, Stryker Neurovascular. A. Wakhloo: 1; C; Philips Medical. 2; C; Stryker Neurovascular. 3; C; Harvard Postgraduate Course and Miami Baptist Vascular Institute. A. Puri: None.

Objectives To characterize carotid stent platform usage, features of the atherosclerotic carotid lesion to be treated, and outcomes of patients who underwent carotid artery stenting (CAS) deemed too high-risk for carotid endarterectomy (CEA). The primary outcomes were stroke and death related to a neurologic or cardiac event during the in-hospital period as well as at 30 and 90 days following CAS. Stroke was defined as new neurologic deficits (motor, sensitive, cognitive) documented on the patient’s medical records following the carotid artery stenting (CAS) procedure and/or MRI evidence of new hyperintense DWI (with corresponding hypointensity on ADC maps) lesions in the ipsilateral hemisphere. Methods We retrospectively reviewed 95 consecutive patients undergoing CAS procedures at a single academic tertiary care center between November of 2010 and December of 2014. Only patients who were considered too high-risk for CEA by their referring physician (neurologist, neurosurgeon, vascular surgeons or primary care physicians) were included in this study. Patients with an acutely occluded internal carotid artery (ICA) and an occluded ipsilateral cerebral vessel (tandem lesions), carotid artery dissection, subarachnoid hemorrhage, acute stroke, or undergoing general anesthesia were excluded from analysis. Overall, it was felt that these excluded patients represented subgroups with even higher procedural risks as opposed to elective cases. Patients who in addition to the above mentioned carotid stents had off-label use of other stents in their carotids (e.g. Wingspan or Neuroform) were also excluded. One patient who received proximal embolic protection was also excluded. We compared baseline clinical characteristics of the patients and characteristics of the treated stenosis, and crude and multivariable adjusted rates of in-hospital combined death/stroke. We compared patients treated with Precise (Cordis Corporation, Bridgewater, New Jersey) as well as Acculink and XACT (both Abbott Laboratories, Abbott Park, Illinois) stents. Last, we compared the immediate postprocedural residual stenosis following CAS. Results Of 95 patients referred for CAS during the study period, 38 high-risk patients met the inclusion criteria and were included for the current analysis: XACT (n = 14), Precise (n = 15), Acculink (n = 5), and combined CAS platforms (e.g. XACT + Precise, n = 4). The overall immediate pre-procedural stenosis degree among the 38 cases was 55% +/- 18% and the overall immediate post-procedural residual carotid stenosis was 18% +/- 14%. There were no significant differences between devices regarding pre-procedural stenosis or post-procedural residual stenosis at this early time point. Most importantly, there were no strokes by discharge, 30 days, and 90 days following CAS. Furthermore, no deaths occurred by discharge and 30 days. One patient had died by 90 days related to multi-organ failure secondary to a septic joint. Conclusions Our study indicates that CAS can be safely performed in patients considered too high-risk for CEA and who were referred to our center as such by their physicians. Disclosures J. Lozano: None. F. Massari: None. C. Brooks: None. M. Perras: None. M. Howk: None. M. Gounis: 1; C; NIH, Philips Healthcare, Covidien/eV3 Neurovascular, Codman Neurovascular, Stryker Neurovascular, Wyss Institute, Tay Sachs Foundation. 2; C; Stryker Neurovascular. N. Henninger: None. A. Wakhloo: 1; C; Phillips Healthcare Medical. 2; C; Stryker. 3; C; Harvard Postgraduate Course, Miami Baptist Vascular Institute. A. Puri: 1; C; Stryker. 2; C; Codman, Covidien.

Introduction Interventional neuroradiology provides increasingly safe and minimally invasive treatment options for neurovascular diseases, but the growing use of diagnostic and complicated fluoroscopy-guided procedures has led to heightened concerns over ionizing radiation exposure to patients and staff. AlluraClarity (Philips Healthcare) is a new commercially available angiographic imaging platform that addresses these concerns by employing novel algorithm- and hardware adjustments that allow for dose reduction while preserving image quality. In this study we report a comparison between AlluraClarity and its predecessor platform (Allura Xper) in a retrospective case review to assess the achieved reduction in mean radiation dose for various neurointerventional procedures. Materials and methods This review was conducted under an IRB-approved data registry. Cumulative dose area product (DAP) and total fluoroscopy time were collected for cases imaged on the Allura Xper (n = 659) and AlluraClarity (n = 329) platforms. Cases were stratified into 8 procedure categories: AVM embolization, carotid stenting, aneurysm coil embolization, diagnostic angiography, flow diverter implantation, stent coiling, thrombectomy, and other (see Table 1). Linear models were fitted to assess the effects of platform by procedure type on both cumulative DAP and total fluoroscopy time. Results Linear modeling showed that the AlluraClarity platform is associated with a significant (p Conclusion The introduction of the AlluraClarity imaging platform was associated with a significant reduction in radiation dose exposure for diagnostic and treatment procedures as compared to Allura Xper. While on average the cumulative DAP was reduced by 48%, this did not lead to an overall increase in total fluoroscopy time. Future work will incorporate the impact on staff dose and operator behavior in complex cases where patient exposure becomes a limiting factor. Disclosures K. van der Marel: None. S. Vedantham: None. I. van der Bom: 5; C; Philips Healthcare. M. Howk: None. T. Narain: None. M. Gounis: 1; C; Philips Healthcare, eV3/Covidien, NIH, Silk Road, Stryker Neurovascular. 2; C; Stryker Neurovascular, Codman Neurovascular. A. Puri: None. A. Wakhloo: 1; C; Philips Healthcare, NIH. 2; C; Stryker Neurovascular.

Isolated middle cerebral artery dissection is a rare clinical entity, with descriptions limited to a few case reports and case series. Symptomatic dissection in the anterior circulation can present as an ischemic stroke in a young population; however, it is rarely associated with subarachnoid hemorrhage. We describe a young patient who presented with acute headache from a subarachnoid hemorrhage that was ultimately determined to be due to a vascular dissection in the middle cerebral artery. The initial angiogram showed vascular irregularities in this area with stenosis. Repeat imaging 4 days after presentation identified a pseudoaneurysm proximal to the stenosis. The patient was successfully treated with a self-expanding nitinol stent and followed up with serial angiography during postoperative recovery in the hospital; additional angiograms were performed approximately 1 and 6 months after treatment. Serial angiograms demonstrated incremental healing of the dissection. The patient was discharged and remains neurologically intact at the 6-month follow-up.