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Intravascular imaging has emerged as a valuable tool for the treatment of coronary and peripheral artery disease; however, no solution is available for safe and reliable use in the tortuous vascular anatomy of the brain. Endovascular treatment of stroke is delivered under image guidance with insufficient resolution to adequately assess underlying arterial pathology and therapeutic devices. High-resolution imaging, enabling surgeons to visualize cerebral arteries' microstructure and micron-level features of neurovascular devices, would have a profound impact in the research, diagnosis, and treatment of cerebrovascular diseases. Here, we present a neurovascular high-frequency optical coherence tomography (HF-OCT) system, including an imaging console and an endoscopic probe designed to rapidly acquire volumetric microscopy data at a resolution approaching 10 microns in tortuous cerebrovascular anatomies. Using a combination of in vitro, ex vivo, and in vivo models, the feasibility of HF-OCT for cerebrovascular imaging was demonstrated., High resolution intravascular imaging in the brain is limited by the high tortuosity of the vasculature. Here the authors present a fiber optic imaging technology using high-frequency optical coherence tomography (HF-OCT) to provide volumetric high resolution images in the highly tortuous cerebral vasculature.

Background Tissue growth over covered branches is a leading cause of delayed thrombotic complications after flow-diverter stenting (FDS). Due to insufficient resolution, no imaging modality is clinically available to monitor this phenomenon. Objective To evaluate high-frequency optical coherence tomography (HF-OCT), a novel intravascular imaging modality designed for the cerebrovascular anatomy with a resolution approaching 10 microns, to monitor tissue growth over FDS in an arterial bifurcation model. Methods FDS were deployed in a rabbit model (n = 6), covering the aortic bifurcation. The animals were divided in different groups, receiving dual antiplatelet therapy (DAPT) (n = 4), aspirin only (n = 1), and no treatment (n = 1). HF-OCT data were obtained in vivo at 3 different time points in each animal. For each cross-sectional image, metal and tissue coverage of the jailed ostium was quantified. Scanning electron microscopy images of harvested arteries were subsequently obtained. Results Good quality HF-OCT data sets were successfully acquired at implant and follow-up. A median value of 41 (range 21-55) cross-sectional images were analyzed per ostium for each time point. Between 0 and 30 d after implant, HF-OCT analysis showed a significantly higher ostium coverage when DAPT was not given. After 30 d, similar growth rates were found in the DAPT and in the aspirin group. At 60 d, a coverage of 90% was reached in all groups. Conclusion HF-OCT enables an accurate visualization of tissue growth over time on FDS struts. The use of FDS in bifurcation locations may induce a drastic reduction of the jailed-branch ostium area.

BackgroundExisting travel restrictions limit the mobility of proctors, significantly delaying clinical trials and the introduction of new neurointerventional devices. We aim to describe in detail technical and legal considerations regarding international teleproctoring, a tool that could waive the need for in-person supervision during procedures.MethodsInternational teleproctoring was chosen to provide remote supervision during the first three intracranial aneurysm treatments with a new flow diverter (currently subject of a clinical trial) in the US. Real-time, high-resolution transmission software streamed audiovisual data to a proctor located in Canada. The software allowed the transmission of images in a de-identified, HIPAA-compliant manner.ResultsAll three flow diverters were implanted as desired by operator and proctor and without complication. The proctor could swap between images from multiple sources and reported complete spatial and situational awareness, without any significant lag or delay in communication. Procedural times and radiologic dose were similar to those of uncomplicated, routine flow diversion cases at our institution.ConclusionsInternational teleproctoring was successfully implemented in our clinical practice. Its first use provided important insights for establishing this tool in our field. With no clear horizon for lifting the current travel restrictions, teleproctoring has the potential to remove the need for proctor presence in the angiography suite, thereby allowing the field to advance through the continuation of trials and the introduction of new devices in clinical practice. In order for this tool to be used safely and effectively, highly reliable connection and high-resolution equipment is necessary, and multiple legal nuances have to be considered.

Purpose Treatment of dural arteriovenous fistulae (DAVFs) is based on obliteration of the fistula via trans-arterial/trans-venous approaches or a combination thereof. In complex cases it can be difficult to determine the fistulous point, and large segments of normal vascular structures are sacrificed to cure the fistulae. High-resolution intraoperative contrast-enhanced cone beam CT (CE-CBCT) allows visualization of arteriovenous vascular structures and their relationship with bony structures and the dura. We present 2 cases of complex DAVFs in which CE-CBCT, by clearly showing the fistulous point, allowed a targeted treatment that avoided unnecessary venous sacrifice and maintained/restored functionality of normal venous structures. Materials and Methods In two patients who presented with complex DAVFs, DSA was insufficient in clarifying the anatomy of the shunt. CE-CBCT was obtained on a last generation biplane Neuroangiography system infusing a 69 mL bolus (30% Visipaque 270) at a rate of 3 mL/second into the main arterial feeder (22 cm FOV; 23 second 200-degree rotation). High-resolution volumetric data generated was reconstructed using an FBP algorithm and post-processed on a dedicated workstation for final treatment strategy. Results A 90-year-old man with progressively slurred speech, had a petrosal/tentorial Cognard 4 DAVF fed by multiple left ECA feeders. CE-CBCT demonstrated an enlarged draining petrosal dural venous pouch draining in the basal vein of Rosenthal. Access route to the pouch was planned on CE-CBCT reconstructions (Image A, dotted line), allowing selective occlusion with coils and Onyx with complete resolution of the DAVF and preservation of normal deep venous structures. The patient’s symptoms resolved shortly following the procedure.The second subject, a 49-year-old man presented with debilitating right-sided pulsatile tinnitus, blurred vision and headaches. A DSA demonstrated a complex, Cognard 1 fistula of the right sigmoid sinus with innumerable external carotid artery (ECA) feeders and loss of drainage functionality of the right transverse-sigmoid sinus. CE-CBCT showed feeders converging in a dural venous pouch adjacent to the postero-lateral wall of the sigmoid sinus (Image B, stars). Similarly to prior case, a CE-CBCT-planned microcathetarization was performed with targeted obliteration of the pouch with coils and Onyx followed by DAVF resolution and restoration of normal antegrade venous flow. Tinnitus resolved, but blurred vision and headaches persisted. Venous pressure measurements demonstrated a 10-mmHg gradient across the narrowed sigmoid sinus. Venous stenting led to complete symptom resolution. Conclusion High-resolution CE-CBCT allows identification of fistulous connections in complex DAVFs and supports an accurate and minimally-deconstructive treatment with sparing of normal venous structures. Disclosures E. Orru: None. M. Marosfoi: None. N. Patel: None. A. Wakhloo: None.

The first-pass effect during mechanical thrombectomy improves clinical outcomes regardless of first-line treatment approach, but current success rates for complete clot capture with one attempt are still less than 40%. We hypothesize that the ThrombX retriever (ThrombX Medical Inc.) can better engage challenging clot models during retrieval throughout tortuous vasculature in comparison with a standard stent retriever without increasing distal emboli.Thrombectomy testing with the new retriever as compared to the Solitaire stent retriever was simulated in a vascular replica with hard and soft clot analogs to create a challenging occlusive burden. Parameters included analysis of distal emboli generated per clot type, along with the degree of recanalization (complete, partial or none) by retrieval device verified by angiography.The ThrombX device exhibited significantly higher rates of first-pass efficacy (90%) during hard clot retrieval in comparison with the control device (20%) (p 0.009), while use of both techniques during soft clot retrieval resulted in equivalent recanalization. The soft clot model generated higher numbers of large emboli (200 μm) across both device groups (p = 0.0147), and no significant differences in numbers of distal emboli were noted between the ThrombX and Solitaire techniques.Irrespective of clot composition, use of the ThrombX retriever demonstrated high rates of complete recanalization at first pass in comparison with a state-of-the-art stent retriever and proved to be superior in the hard clot model. Preliminary data suggest that risk of distal embolization associated with the ThrombX system is comparable to that of the control device.

BackgroundDespite high recanalization rates achieved with endovascular treatment of acute ischemic strokes, around 50% of eligible patients will not achieve a good outcome. Parameters that may determine patient outcomes include: time from puncture to recanalization, the collateral status, the anesthesia regimen, blood pressure management, and distal emboli. Characterization of distal emboli generated during mechanical thrombectomy has been performed in previous studies.ObjectiveTo further investigate the risk of distal embolization associated with microcatheter navigation across the clot.MethodsA contrast-enhanced clot analog was used in an in vitro model that mimicked a middle cerebral artery occlusion within a complete circle of Willis vascular replica. The clot was crossed with one of the following microcatheters: Pro18, XT-27 or 3MAX. The emboli generated during the procedure were collected and measured.ResultsThe use of Pro18 and XT-27 resulted in a significant reduction of visible particles (size ≥500 µm) as compared with the 3MAX catheter (P0.05). In comparison with previously published data, acquired under the same conditions, it was found that the clot crossing maneuver accounts approximately for 12% of the total number of small emboli (ConclusionsThe clot crossing maneuver has a significant effect on the total number of small particles induced during mechanical thrombectomy. Smaller microcatheter sizes should be favored when possible.

PurposeThromboembolic complications remain a limitation of flow diverting stents. We hypothesize that phosphorilcholine surface modified flow diverters (Pipeline Flex with Shield Technology, sPED) would have less acute thrombus formation on the device surface compared with the classic Pipeline Embolization device (cPED).MethodsElastase-induced aneurysms were created in 40 rabbits and randomly assigned to receive cPED or sPED devices with and without dual antiplatelet therapy (DAPT) (four groups, n=10/group). Angioplasty was performed to enhance apposition and create intimal injury for a pro-thrombotic environment. Both before and after angioplasty, the flow diverter was imaged with intravascular optical coherence tomography. The outcome measure was the number of predefined segments along the implant relative to the location of the aneurysm with a minimum of 0 (no clot formation) and maximum of 3 (all segments with thrombus). Clot formation over the device at ostia of branch arteries was assessed as either present or absent.ResultsFollowing angioplasty, the number of flow diverter segments with clots was significantly associated with the flow diverter (pConclusionIn the rabbit model, phosphorilcholine surface modified flow diverters are associated with less thrombus formation on the surface of the device.

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.

Global gene delivery to the CNS has therapeutic importance for the treatment of neurological disorders that affect the entire CNS. Due to direct contact with the CNS, cerebrospinal fluid (CSF) is an attractive route for CNS gene delivery. A safe and effective route to achieve global gene distribution in the CNS is needed, and administration of genes through the cisterna magna (CM) via a suboccipital puncture results in broad distribution in the brain and spinal cord. However, translation of this technique to clinical practice is challenging due to the risk of serious and potentially fatal complications in patients. Herein, we report development of a gene therapy delivery method to the CM through adaptation of an intravascular microcatheter, which can be safely navigated intrathecally under fluoroscopic guidance. We examined the safety, reproducibility, and distribution/transduction of this method in sheep using a self-complementary adeno-associated virus 9 (scAAV9)-GFP vector. This technique was used to treat two Tay-Sachs disease patients (30 months old and 7 months old) with AAV gene therapy. No adverse effects were observed during infusion or post-treatment. This delivery technique is a safe and minimally invasive alternative to direct infusion into the CM, achieving broad distribution of AAV gene transfer to the CNS.

Introduction The development of High Frequency OCT1 (HF-OCT) allows for higher resolution intra-arterial imaging, such that vascular remodeling in response to stents and next generation intrasaccular devices (NGID) can be interrogated. We hypothesize that imperfections or gaps in the neck coverage of an aneurysm after treatment with a NGID will be predictive of failed aneurysm occlusion. Materials and methods Two aneurysms were made in each of six dogs, one sidewall aneurysm on the distal right common carotid artery (CCA), and a bifurcation aneurysm proximally at the apex of an anastomosis between the left and right CCAs. One aneurysm was excluded due to thrombosis at the time of treatment. Each aneurysm was treated with either detachable coils, or NGID, with a 7:4 randomization NGID:COIL. At implant, HF-OCT was obtained after each aneurysm was successfully packed. At 180 days, animals were assessed for final aneurysm occlusion by DSA. Separately, the HF-OCT data sets were automatically segmented such that gaps in the coverage of the aneurysm neck could be identified and used to predict if the aneurysm occlusion at 180 days. Results The overall rate of occlusion was not seen to be different between the NGID and COIL group (p=0.45) on the Raymond-Roy scale.2 All of the NGID constructs were successfully segmented, and the associated larges gap in the neck coverage for each was determined. A gap in the NGID construct at the level of the neck greater than 1 mm2 predicted failed aneurysm occlusion at 180-days (p = 0.047). This threshold correctly classified all aneurysms. Conclusions HF-OCT allows not only for the imaging and segmentation of intra-arterial devices in vivo, but showed great potential as a robust diagnostic tool. Preliminary evidence collected in this study showed that HF-OCT can prognosticate aneurysm treatment success at the time of treatment. References Stroke. 2018:Nov29:STROKEAHA118022315 Stroke. 2003;34(6):1398–1403. Disclosures R. King: None. M. Marosfoi: None. J. Caroff: None. G. Ughi: 4; C; Gentuity LLC. 5; C; Gentuity LLC. D. Groth: None. M. Gounis: None. A. Puri: None.

Introduction The use of stents in the treatment of wide neck aneurysms, and more recently the adoption of flow diverters, are important tools for the treatment of aneurysms.1 One major complication of such implants is thromboembolism, requiring the use of dual anti-platelet therapy (DAPT). However, due to variable response and inherent risks of DAPT, new stents are being developed with anti-thrombogenic coatings with the goal to reduce or eliminate the need for DAPT. Methods A novel hydrophilic polymer coating (HPC) applied to a nitinol substrate has been shown to resist platelet aggregation in vitro.2 We sought to demonstrate preliminary evidence to confirm this observation in vivo. Three pigs were used with different regimens: no antiplatelet medication (NAPT), 81 mg aspirin (SAPT), and 81 mg aspirin with 75 mg Clopidogrel (DAPT). Two control and two coated devices were implanted in each animal. High Frequency Optical Coherence Tomography (HF-OCT), with a spatial resolution approaching 10 microns, was used to study acute thrombus formation along the surface of the device. HF-OCT acquisitions were acquired 20 minutes following device implant. Specifically, the total clot volume on each side branch opening (SBO) was segmented with manual input by a blinded user. Statistical analyses were performed to determine the relative benefit of the HPC coating and the antiplatelet regiment for prevention of platelet aggregation, a linear model was constructed to interrogate the relative importance. Results The figure 1 shows one section from each device type. It was found that device type and aspirin where significantly correlated with thrombus volume over SBOs. Mean thrombus volume per mm2 of SBO for coated versus control devices was 0.00033 mm versus 0.087 mm, respectively (p = 0.005). Mean clot per SBO was 0.004 mm versus 0.15 mm in animals receiving aspirin versus NAPT (p Conclusions This preliminary evidence shows the dramatic effect that the coating can have on the acute thrombus formation. Further, this novel HF-OCT technology allows for quantitative measurements of the amount of thrombus formed on the surface of a flow diverter, not just the presence. Finally, this study shows the possibility that the combined effect of aspirin and this new coating may be sufficient antiplatelet therapy. References Neurosurgery 2017;80:40–48. CardioVasc Intervent Radiol 2018;41:1779–1785. Disclosures R. King: None. E. Langan: None. M. Marosfoi: None. G. Ughi: 4; C; Gentuity LLC. 5; C; Gentuity LLC. C. Raskett: None. M. Gounis: 2; C; Phenox

PurposeTo develop a preclinical model of stroke with a large vessel occlusion treated with mechanical thrombectomy.Materials and methodsAn ischemic stroke model was created in dogs by the introduction of an autologous clot into the middle cerebral artery (MCA). A microcatheter was navigated to the clot and a stent retriever thrombectomy was performed with the goal to achieve Thrombolysis in Cerebral Ischemia (TICI) 2b/3 reperfusion. Perfusion and diffusion MRI was acquired after clot placement and following thrombectomy to monitor the progression of restricted diffusion as well as changes in ischemia as a result of mechanical thrombectomy. Post-mortem histology was done to confirm MCA territory infarct volume.ResultsInitial MCA occlusion with TICI 0 flow was documented in all six hound-cross dogs entered into the study. TICI 2b/3 revascularization was achieved with one thrombectomy pass in four of six animals (67%). Intra-procedural events including clot autolysis leading to spontaneous revascularization (n=1) and unresolved vasospasm (n=1) accounted for thrombectomy failure. In one case, iatrogenic trauma during microcatheter navigation resulted in a direct arteriovenous fistula at the level of the cavernous carotid. Analysis of MRI indicated that a volume of tissue from the initial perfusion deficit was spared with reperfusion following thrombectomy, and there was also a volume of tissue that infarcted between MRI and ultimate recanalization.ConclusionWe describe a large animal stroke model in which mechanical thrombectomy can be performed. This model may facilitate, in a preclinical setting, optimization of complex multimodal stroke treatment paradigms for clinical translation.

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 Early and mid-term safety and efficacy of aneurysm treatment with the Pipeline Embolization Device (PED) has been well demonstrated in prior studies. Objective To present 5-yr follow-up for patients treated in the Pipeline for Uncoilable or Failed Aneurysms clinical trial. Methods In our prospective, multicenter trial, 109 complex internal carotid artery (ICA) aneurysms in 107 subjects were treated with the PED. Patients were followed per a standardized protocol at 180 d and 1, 3, and 5 yr. Aneurysm occlusion, in-stent stenosis, modified Rankin Scale scores, and complications were recorded. Results The primary endpoint of complete aneurysm occlusion at 180 d (73.6%) was previously reported. Aneurysm occlusion for those patients with angiographic follow-up progressively increased over time to 86.8% (79/91), 93.4% (71/76), and 95.2% (60/63) at 1, 3, and 5 yr, respectively. Six aneurysms (5.7%) were retreated. New serious device-related events at 1, 3, and 5 yr were noted in 1% (1/96), 3.5% (3/85), and 0% (0/81) of subjects. There were 4 (3.7%) reported deaths in our trial. Seventy-eight (96.3%) of 81 patients with 5-yr clinical follow-up had modified Rankin Scale scores ≤2. No delayed neurological deaths or hemorrhagic or ischemic cerebrovascular events were reported beyond 6 mo. No recanalization of a previously occluded aneurysm was observed. Conclusion Our 5-yr findings demonstrate that PED is a safe and effective treatment for large and giant wide-necked aneurysms of the intracranial ICA, with high rates of complete occlusion and low rates of delayed adverse events.

BackgroundHigh frequency optical coherence tomography (HF-OCT) is a novel intravascular imaging technology developed for use in the cerebral vasculature. We hypothesize that HF-OCT characterization of intrasaccular device neck coverage can prognosticate exclusion of the aneurysm from the circulation.MethodsBifurcation and sidewall aneurysms were made in six dogs. Seven aneurysms were treated with next generation intrasaccular devices (NGID) and four with traditional platinum coils. HF-OCT was performed to interrogate gaps in the neck coverage, coil herniation, or acute thrombus formation. Animals were re-imaged at 7, 30, 90, and 180 days following aneurysm embolization. An automated image processing method segmented the devices at the neck of the aneurysm and quantified neck coverage. The largest coverage gap was used to predict aneurysm occlusion at 180 days.ResultsNo difference was found in occlusion rates between the coil and NGID groups (P=0.45). Successful segmentation of the NGID construct was achieved in all cases. A coverage gap >1 mm2 was found to predict failed aneurysm occlusion (P=0.047). This threshold was able to predict all cases of failed occlusion. The average number of devices needed to treat the aneurysm was lower in the NGID group (1.9 vs 6.75, P=0.009). HF-OCT showed strong agreement with scanning electron microscopy (bias 0.0024 mm2 (95% CI −0.0279, 0.0327)).ConclusionsHF-OCT enables precise and accurate measurement of coverage gaps at the neck of aneurysms treated with intrasaccular devices in vivo. We provide in vivo evidence that uniform aneurysm neck coverage by intrasaccular devices is critical for aneurysm occlusion.

BackgroundEvidence is mounting that first-pass complete recanalization during mechanical thrombectomy is associated with better clinical outcomes in patients presenting with an emergent large vessel occlusion. We hypothesize that aspiration achieving complete clot ingestion results in higher first-pass successful recanalization with quantitative reduction in distal emboli.MethodsA patient-specific cerebrovascular replica was connected to a flow loop. Occlusion of the middle cerebral artery was achieved with clot analogs. Independent variables were the diameter of the aspiration catheter (0.054–0.088in) and aspiration pattern (static versus cyclical). Outcome measures were the first-pass rates of complete clot ingestion, the extent of recanalization, and the particle-size distribution of distal emboli.ResultsAll aspiration catheters were successfully navigated to the occlusion. Complete clot ingestion during aspiration thrombectomy resulted in first-pass complete recanalization in every experiment, only achieved in 21% of experiments with partial ingestion (PConclusionsComplete clot ingestion results in fewer distal emboli and the highest rates of first-pass complete recanalization. The rate of complete ingestion during aspiration thrombectomy is a function of both the inner diameter of the aspiration catheter and use of cyclical aspiration.

Introduction Distal embolization as a result of mechanical thrombectomy during treatment of acute ischemic stroke is one of the parameters that may determine patient outcome. The aims of this study are 1) to assess the risk of distal embolization associated with varying thromboaspiration techniques in comparison to the standard balloon guide catheter assisted stent-retriever thrombectomy (BGC+SR), and 2) to understand how different extents of clot ingestion (complete vs partial) into the aspiration catheter during thromboaspiration affect the rate of first-pass recanalization. Methods An experimental model with a circulating flow loop and cerebrovascular phantom was assembled to perform thrombectomy via BGC+SR (FlowGate, Stryker Neurovascular, Fremont, CA; Solitaire, Medtronic Neurovascular, Irvine, CA) and test aspiration efficacy of the following four catheters: the R92M 088 and 070 Reperfusion Systems (Route 92 Medical, Inc., San Mateo, CA), Penumbra ACE068 and 5MAX (054 inch internal diameter) (Penumbra Inc., Alameda, CA) (min. n=5 per group; one thrombectomy attempt per experiment). Five additional replicates per clot type were performed to elaborate findings obtained from the R92M 088 and BGC+SR groups. Two different clot types were utilized to form an MCA occlusion: a fibrin-rich hard clot supplemented with hydroxyapatite and a soft clot model with the addition of barium proven prone to fragmentation. Thromboaspiration took place once the tip of the aspiration catheter was placed proximal to the occlusion and followed by continuous aspiration for 2.5 min. Complete clot ingestion was defined as visible capture of the entire clot, whereas partial clot ingestion was a visible portion of clot outside the distal end of the aspiration catheter. Clot fragments generated during each technique were collected for particle analysis using the Coulter Principle. Results Successful recanalization was demonstrated in 100% of cases with complete clot ingestion and in 55% of cases with partial clot ingestion. R92M 088 and BGC+SR achieved >80% recanalization rate with the hard clot, resulting in a total of 0 and 4 visible particles respectively. For the remaining devices, the recanalization rate was Conclusion Both the BGC+SR and R92M 088 techniques were effective for clot removal and comparable in terms of distal embolization. The rate of first-pass successful recanalization was reduced by nearly 50% with partial clot ingestion during thromboaspiration in comparison to complete clot ingestion. Reference Stroke 2013;44:1396–1401. Disclosures R. Arslanian: None. J. Caroff: None. M. Marosfoi: None. R. King: None. S. Wilson: 5; C; employee of Route 92 Medical. M. Gounis: 1; C; Medtronic Neurovascular, Stryker Neurovascular, Cerenovus Neurovascular, The Stroke Project, Route 92 Medical, InNeuroCo, Mivi Neurosciences,. 2; C; Cerenovus Neurovascular, Medtronic Neurovascular, Phenox, Stryker Neurovascular, The Stroke project, Route 92 Medical, InNeuroCo,. 4; C; InNeuroCo, The Stroke Project. J. Chueh: None.

PurposeRapid revascularization in emergent large vessel occlusion with endovascular embolectomy has proven clinical benefit. We sought to measure device–clot interaction as a potential mechanism for efficient embolectomy.MethodsTwo different radiopaque clot models were injected to create a middle cerebral artery occlusion in a patient-specific vascular phantom. A radiopaque stent retriever was deployed within the clot by unsheathing the device or a combination of unsheathing followed by pushing the device (n=8/group). High-resolution cone beam CT was performed immediately after device deployment and repeated after 5 min. An image processing pipeline was created to quantitatively evaluate the volume of clot that integrates with the stent, termed the clot integration factor (CIF).ResultsThe CIF was significantly different for the two deployment variations when the device engaged the hard clot (p=0.041), but not the soft clot (p=0.764). In the hard clot, CIF increased significantly between post-deployment and final imaging datasets when using the pushing technique (p=0.019), but not when using the unsheathing technique (p=0.067). When we investigated the effect of time on CIF in the different clot models disregarding the technique, the CIF was significantly increased in the final dataset relative to the post-deployment dataset in both clot models (p=0.004–0.007).ConclusionsThis study demonstrates in an in vitro system the benefit of pushing the Trevo stent during device delivery in hard clot to enhance integration. Regardless of delivery technique, clot–device integration increased in both clot models by waiting 5 min.

Imaging inflammation in large intracranial artery pathology may play an important role in the diagnosis of and risk stratification for a variety of cerebrovascular diseases. Looking beyond the lumen has already generated widespread excitement in the stroke community, and the potential to unveil molecular processes in the vessel wall is a natural evolution to develop a more comprehensive understanding of the pathogenesis of diseases, such as ICAD and brain aneurysms.

BACKGROUND AND PURPOSE: Treatment of giant fusiform aneurysms with flow diverters has been associated with a relatively high rate of complications. Our goal was to study the evolution of flow-diverter endothelialization and thrombus organization at different time points after flow-diverter treatment in giant fusiform aneurysms to better understand reasons for flow-diverter thrombosis and delayed aneurysm ruptures. MATERIALS AND METHODS: Two giant anterior and 2 posterior circulation aneurysms, all of which had partially thrombosed before treatment, were studied. An unruptured, untreated posterior circulation aneurysm was used as a control. Each specimen was removed at 7 days or at 6, 9, or 13 months after flow-diverter treatment. The 3 patients who survived longer than 7 days were followed up by angiography and MR imaging. Formaldehyde-fixed paraffin-embedded sections were stained by using H&E, Van Gieson elastic, CD34, h-Caldesmon, and Picrosirius stains and studied by light microscopy. RESULTS: According to angiography, aneurysms were found to be obliterated partially at 6 and 9 months and completely at 13 months. MR imaging revealed that mass effect remained unchanged in each case. Sections of the flow diverter within the normal parent artery were covered by an endothelialized fibrous layer as early as 6 months, but there was no tissue coverage or endothelialization seen even at 13 months inside the aneurysm itself. Each treated aneurysm had a thin wall with complete lack of smooth muscle cells. No signs of thrombus organization were found at any of the time points studied. CONCLUSIONS: Endothelialization of the flow diverter in giant fusiform aneurysms may not occur and thrombus organization may not be initiated inside these aneurysms for as long as 1 year, which explains delayed flow-diverter thrombosis and the possibility of delayed ruptures.

BackgroundOptical coherence tomography (OCT) is a high-resolution, intra-vascular diagnostic technique widely used for the characterization of vascular pathologies and optimization of stent implantation during percutaneous coronary intervention. OCT was used to investigate the in vivo vascular response to a new phosphorylcholine surface modified flow diverter (sPED).MethodsIn an in vivo rabbit aneurysmal model, we used two different types of flow diverters (classic Pipeline – cPED; and sPED) with or without dual antiplatelet therapy (four groups, n=10 per group). OCT cross-sectional area measurements were compared with histology in all animals. Neointimal hyperplasia (NIH) ratio was compared between OCT and histology at five different levels for each stent. The severity of NIH was also compared between the different stents, antiplatelet protocols, and vessel locations.ResultsOCT was used to calculate in-stent hyperplasia in 227 different locations corresponding to histology sections. OCT measurement strongly correlated with gold standard histology (r2=0.83; slope=0.988; PConclusionOCT is a promising technique for immediate and long-term evaluation of flow diverter stent treatments. In an animal model, phosphorylcholine surface modified flow diverters induces less NIH after stent implant without reducing aneurysm occlusion rates.

Introduction/Purpose In-stent stenosis and intimal hyperplasia (IH) occur in 9% and 35%, respectively, after flow diverter treatment1. Although this phenomenon is not rare, severe, symptomatic flow limiting narrowing is rarely observed. Recently FD have been used in several cases in small vessels (off-label indication), which can potentially result in a higher rate of symptomatic in-stent stenosis or stent thrombosis. We sought to determine the patterns of intimal hyperplasia after flow diversion treatment using a high resolution intravascular imaging technique (optical coherence tomography). Furthermore, we assessed the effect of phosphoryl-choline surface modified FDs in preventing in-stent stenosis. Materials and methods Forty New-Zealand white rabbits with elastase induced aneurysm were treated with classic Pipeline (C-PED) or with Pipeline-Flex with Shield Technology (S-PED). Four treatment groups were created, based on device type and the usage of dual anti-platelet therapy (DAPT). Ten animals per group were randomized for the following treatment: C-PED-no-DAPT, C-PED-with-DAPT, S-PED-no-DAPT, S-PED-with-DAPT. Optical coherence tomography was used in order to determine the location, thickness and the vessel involvement of intimal hyperplasia. Intimal hyperplasia was considered when the newly formed intraluminal tissue exceeded 0.1 mm in thickness and in stent stenosis when the lumen narrowing was >20%. Results Intimal hyperplasia developed at two specific locations: at the mid-segment of FD (at the inner curve of the innominate artery), presented as a focal IH with a mean thickness of 0.11–0.16 mm. And at the distal end of FD, where the mean device/vessel ratio >1.8, presented as circumferential hyperplasia with mean IH: 0.14–0.22 mm. Mild in-stent stenosis (20%–50%) was only seen distal to the vertebral artery. In stent stenosis was identified in 5 cases (50%) in C-PED group with and without DAPT, in 33% in S-PED-no-DAPT and in 0% in S-PED-with-DAPT. Phosphoryl-choline surface modified FD with DAPT showed a significant (Fisher’s exact, p Conclusions Our preliminary study suggests that the distal end of the FD (landed in small vessel) and the area of high metal density (mid-portion of FD) are more prone to develop intimal hyperplasia. Furthermore, using phosphoryl-choline surface modified flow diverters can be beneficial in preventing in-stent stenosis in small vessels. Reference . Neurosurgery. 2016;78:862–867 Disclosures M. Marosfoi: None. F. Clarencon: None. E. Langan: None. R. King: None. O. Brooks: None. T. Tamura: None. J. Wainwright: 5; C; Medtronic Neurovascular. M. Gounis: 1; C; Medtronic Neurovascular. A. Puri: 1; C; Medtronic Neurovascular.

Introduction/Purpose Safety and efficacy of thrombectomy devices are assessed in large animal models with extracranial vascular occlusions 1 . These models do not incorporate important features of cerebrovascular thrombectomy, such as downstream emboli and cerebrovascular trauma 2 . We refine our previously developed canine ischemic stroke model 3 to: (Aim 1) create a reproducible occlusion of the MCA, (Aim 2) achieve microcatheter navigation to the clot and (Aim 3) perform stent-retriever thrombectomy (TigerTriever 17, Rapid Medical, Yokneam, Israel). Materials and Methods One mongrel (23.5 kg) and two hound-cross (24 kg) dogs were used for this study. A unilateral occlusion of the MCA was created by injecting autologous, barium-enhanced clot in the first two animals 4 and a fibrin-rich clot in the third. Diffusion-weighted MRI was acquired at 51±7 min after clot injection. Upon confirmation of an ischemic stroke, endovascular treatment was attempted. Results Occlusion of either the MCA (n=2) or the ICA terminus (n=1) was achieved in all animals (Aim 1) . In the first animal, microcatheter access was complicated by perforation during microwire navigation (due to atypically small cerebrovasculature, MCA=0.76 mm) leading to subarachnoid hemorrhage (SAH). Despite successful clot extraction in this animal, documentation of revascularization failed due to increased intracranial pressure from the SAH. Refinement of the technique by using an intermediate catheter (DAC) to achieve better support in an extremely tortuous ICA was incorporated. In the second animal, distal microcatheterization was hampered by clot hardness followed by clot mobilization distally. Further refinement of the modeling included modification of the clot by incorporating fibrininogen and excluding barium. Uncomplicated microcatheter (1.7F) navigation distal to the clot and device delivery was achieved following model optimization (Aim 2) . In all experiments, clot was mobilized and extracted by the controllable-expansion TigerTriever 17 device. In the two cases where reperfusion was documented, TICI 2a and TICI 2b were achieved in animals 2 and 3, respectively (Aim 3) . Ultimately, this model optimization process required: (1) young hound-cross dogs with sufficient arterial diameters of the MCA (1.1±0.1 mm); (2) a tri-axial system with a 6Fr Shuttle sheath in the common carotid artery, a DAC 044 in the cervical ICA, and an SL-10 microcatheter for stent-retriever delivery to the MCA; and (3) modification of the clot model. Conclusion The development of a stroke model amendable to mechanical thrombectomy provides a potential paradigm to study neuroprotection strategies coupled with clinical standard-of-care endovascular treatment. Further reproducibility studies are underway. References . JNIS 2012;4:307–313. . Stroke 2015;46:1099–1106. . AJNR 2012;33:353–358. Disclosures O. Brooks: None. R. King: None. J. Chueh: None. M. Marosfoi: None. E. Nossek: 2; C; Rapid Medical. R. Eckhouse: 5; C; Rapid Medical. M. Gedulter: 5; C; Rapid Medical. M. Gounis: 1; C; Rapid Medical.

Introduction/Purpose Malapposition has a negative correlation to aneurysm healing 1 . We examine the influence of malapposition communicating into the aneurysm, and the effect of malapposition incidence at any position along the parent artery on healing. We define communicating malapposition (CM) as any malapposition along the aneurysm neck (figure 1). We hypothesize that CM seen on optical coherence tomography (OCT) results in lower aneurysm occlusion rates after 30 days, and that malapposition at any other point along the parent artery has no effect. Materials and Methods Fifty New Zealand White rabbits underwent elastase-induced aneurysm creation. 2 After 21 days, animals were randomly implanted with: Pipeline Embolization Device (PED; n=20); Pipeline Embolization Device with Shield technology (SHIELD; n=20); or, Flow Reduction Endoluminal Device (FRED; n=10). Five days prior to implantation, 10 animals from each group began dual antiplatelet therapy (DAPT; aspirin/clopidogrel 10 mg/kg each) which was continued daily until the 30 day terminal endpoint. All animals were used for statistical analysis in this study since the influence of DAPT yielded no significant impact on rates of aneurysm occlusion. All animals underwent post-deployment OCT to assess device/vessel apposition. At 30 days, DSA and OCT were acquired to assess aneurysm healing. The incidence of CM was assessed on a binary scoring system: 0 CM present; 1 CM absent. Aneurysm healing on DSA was measured using a previously developed 5-point scale 3 – a score of 3 or 4 (neck remnant or complete occlusion) was considered a positive outcome. Separately, the presence of malapposition distal to the aneurysm neck was measured on a similar binary scale: 0- malapposition seen distal to aneurysm; 1 – no malapposition observed. A Fisher’s exact test was used to show significance. Results Overall positive aneurysm outcome at 30 days was seen in 50% of cases (n=25), with no CM seen in 80% of those cases (n=20). Significant interaction between no CM and positive outcome was confirmed by a Fisher exact test, p=0.0014. When malapposition incidence along the parent artery distal to the aneurysm was compared to positive outcome, no significant interaction was found, p=0.776. Conclusion OCT shows potential in serving as an indicator of poor outcome in the presence of CM during device implant. From these data, absence of communicating malapposition is strongly associated with early aneurysm occlusion, whereas malapposition distal to the aneurysm showed no effect on rates of aneurysm healing. References . AJNR 2016;37(11):2087–91. 2. AJR . 2000;174:349–354. . AJNR 2012;33(10):2004–9. Disclosures R. King: None. O. Brooks: None. E. Langan: None. M. Marosfoi: None. F. Clarencon: None. T. Tamaura: None. J. Wainwright: 5; C; Medtronic Neurovascular. M. Gounis: 1; C; Medtronic Neurovascular. A. Puri: 1; C; Medtronic Neurovascular.

Introduction A growing body of research has suggested the benefits of mechanical thrombectomy in large vessel occlusion with the use of newer generation of thrombectomy devices. Different device designs may influence the rate of procedural-related embolic events, which is a modifiable risk. The EmboTrap thrombectomy system features an inner stent channel with an outer stent trap design that may potentially reduce the risk of distal clot fragmentation. The objective of this study is the analysis of embolic potential during EmboTrap thrombectomy as compared with existing, FDA-cleared technology for the treatment of acute ischemic stroke. Materials and Methods A hard, inelastic clot was injected into a patient-specific circle of Willis replica to form a middle cerebral artery occlusion. A guide catheter was placed in the cervical ICA, and delivered the guidewire which was then softly advanced through the clot. A microcatheter was navigated over the wire across the occlusive clot. The guidewire was withdrawn followed by device (EmboTrap or Solitaire 2) deployment for mechanical thrombectomy. During retriever retraction, continuous aspiration was applied through an aspiration pump. Twenty experiments were carried out for each device. The maximum number of thrombectomy attempts was limited to 3. Emboli greater than 1000μm were measured with calipers. The Coulter Principle was used to characterize emboli with size between 200µm to 1000µm. Results EmboTrap thrombectomy resulted in a significant reduction in the frequency of large clot fragment (>1000μm) dislodgement as compared to Solitaire thrombectomy (p=0.031, Fisher’s exact test). Formation of emboli greater than 1000μm in size occurred in 3 out of 20 cases in the EmboTrap group, versus 11 of 20 experiments with the Solitaire group. Approximately 80% of >1000μm emboli were found in the MCA, regardless of device type. There was no significant difference in average clot size between EmboTrap and Solitaire groups (size ranging from 1000 to 4000μm) in the >1000μm size range. In the size range between 200 to 1000μm, a broader size distribution of emboli was observed with the Solitaire device (200- 770μm) compared to the EmboTrap device (200–325μm). There was no significant difference between the EmboTrap and Solitaire in 200 to 1000μm emboli formation (p=0.89, Mann-Whitney test). When combining all emboli in the most dangerous range (>200μm), EmboTrap offered size reduction of emboli (p=0.022). A complete flow restoration after a single pass was observed in all cases except for 1 experiment in the EmboTrap group, whereas 2 out 20 cases in the Solitaire group required more than 2 passes to achieve full recanalization. Conclusion Based on this preliminary study, it is our conclusion that stent retriever design can be optimized to alter the particle size distribution of distal emboli. When encountering friable hard clots, the use of the EmboTrap device may provide a reduction in distal emboli to both affected and unaffected territories and should be considered. Disclosures: J. Chueh: None. M. Marosfoi: None. R. King: None. O. Brooks: None. A. Puri: None. M. Gounis: 1; C; research grant. 6; C; Travel Support.

Introduction/Purpose Major ipsilateral ischemic stroke have been reported to range between 1.6%–4.3%1,2 after flow diverter treatment. Patient-specific contributors to peri-procedural thromboembolic complications remain under investigation. Beyond understanding and correcting patient-specific factors, we seek device technology to decrease these unpredictable complications. By using high resolution intravascular imaging tool (optical coherence tomography – OCT) we sought to determine the rate of acute micro-clot formation on the surface of different flow diverters. Furthermore, we assessed the consequences of angioplasty (after FD implant) with respect to acute clot formation. We hypothesize that a new generation phosphoryl-choline surface modified flow diverter may reduce acute clot formation on the surface of the device. Materials and methods Thirty elastase induced aneurysms were created in rabbits and treated with 3 different types of flow diverters. Classic Pipeline (C-PED), Pipeline-Flex with Shield Technology (S-PED) and FRED devices were implanted in 10 animals in each group. Four days prior to implant animals received dual anti-platelet therapy (DAPT: 10 mg/kg aspirin and clopidogrel) and that was continued until the end of the study (30 days). OCT (Dragonfly, St Jude) was used to assess the acute clot formation on the surface of devices, after deployment, and repeated 20 min after angioplasty (Figure). Thrombus formation was analyzed and scored by looking at 3 different locations along the implant. In addition, clot formation at the origins of covered side branches (OSB) was separately scored. Results At the origin of side branches, the S-PED showed a significantly less amount of clot formation both pre- and post-angioplasty (10% and 20%, versus C-PED: 40% and 60% and FRED: 60% and 90%, respectively, p=0.0065). At the 3 other locations (OSB not included): the distal end of the device, proximal end (including the level of the aneurysm) and the location between the aneurysm and the vertebral artery there was no difference in clot formation between the 3 devices immediately after deployment. However, following angioplasty of the devices, a decrease of clot formation was seen only in the S-PED group versus an increase as expected with the other devices (S-PED: 20% decrease, C-PED: 30% increase, FRED: 20% increase). Conclusion Our preliminary study supported our hypothesis that using phosphoryl-choline surface modified flow diverter can be useful to decrease the occurrence of micro-clot formation, especially post-angioplasty. Importantly, S-PED reduced clot formation at the origin of covered side-branches. References . AJNR 2015;36:98–107. . J. Neurosurg 2016;1–6. Disclosures M. Marosfoi: None. F. Clarencon: None. E. Langan: None. R. King: None. O. Brooks: None. T. Tamura: None. M. Gounis: 1; C; Medtronic Neurovascular. A. Puri: 1; C; Medtronic Neurovascular.

Introduction La diversion de flux est une technique efficace pour le traitement des anevrismes intracrâniens, avec des taux d’occlusion eleves au long terme. Toutefois, certains anevrismes ne vont jamais cicatriser et d’autres vont s’occlure de facon retardee. De nombreuses donnees precliniques montrent que la bonne apposition a la paroi est un facteur fondamental a l’occlusion anevrismale. Nous avons compare les taux d’occlusion a moyen terme avec ou sans angioplastie apres la pose d’un stent a diversion de flux. Methodes Entre octobre 2011 et septembre 2016, tous les patients traites a l’aide d’un stent Pipeline pour un anevrisme de la circulation anterieure ont ete inclus. Les criteres d’exclusion etaient l’absence de suivi angiographique (6–24 mois) et l’utilisation concomitante d’un autre type de stent. La presentation clinique, les informations techniques et le suivi etaient conserves dans une banque de donnees prospective. Resultats Au total, 144 anevrismes ont ete inclus, avec un taux d’angioplastie de 52 %. Les caracteristiques demographiques, anevrismales et le suivi angiographique moyen (12 mois) n’etaient pas differents entre les deux groupes. Le taux d’occlusion complete etait plus eleve dans le groupe angioplastie (89 %) que dans le groupe controle (71 %), p = 0,006. L’angioplastie n’a pas entraine de complication hemorragique ni n’etait associe a une utilisation plus frequente d’inhibiteurs de la GPIIb/IIIa (p = 0,2). Lors du suivi il n’y a pas eu d’augmentation de score mRs dans le groupe angioplastie. Conclusion La bonne apposition a la paroi arterielle est un facteur important pour l’occlusion arterielle precoce apres traitement par stent a diversion de flux.

OBJECTIVEThe long-term effectiveness of endovascular treatment of large and giant wide-neck aneurysms using traditional endovascular techniques has been disappointing, with high recanalization and re-treatment rates. Flow diversion with the Pipeline Embolization Device (PED) has been recently used as a stand-alone therapy for complex aneurysms, showing significant improvement in effectiveness while demonstrating a similar safety profile to stent-supported coil treatment. However, relatively little is known about its long-term safety and effectiveness. Here the authors report on the 3-year safety and effectiveness of flow diversion with the PED in a prospective cohort of patients with large and giant internal carotid artery aneurysms enrolled in the Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial.METHODSThe PUFS trial is a prospective study of 107 patients with 109 aneurysms treated with the PED. Primary effectiveness and safety end points were demonstrated based on independently monitored 180-day clinical and angiographic data. Patients were enrolled in a long-term follow-up protocol including 1-, 3-, and 5-year clinical and imaging follow-up. In this paper, the authors report the midstudy (3-year) effectiveness and safety data.RESULTSAt 3 years posttreatment, 74 subjects with 76 aneurysms underwent catheter angiography as required per protocol. Overall, complete angiographic aneurysm occlusion was observed in 71 of these 76 aneurysms (93.4% cure rate). Five aneurysms were re-treated, using either coils or additional PEDs, for failure to occlude, and 3 of these 5 were cured by the 3-year follow-up. Angiographic cure with one or two treatments of Pipeline embolization alone was therefore achieved in 92.1%. No recanalization of a previously completely occluded aneurysm was noted on the 3-year angiograms. There were 3 (2.6%) delayed device- or aneurysm-related serious adverse events, none of which led to permanent neurological sequelae. No major or minor late-onset hemorrhagic or ischemic cerebrovascular events or neurological deaths were observed in the 6-month through 3-year posttreatment period. Among 103 surviving patients, 85 underwent functional outcome assessment in which modified Rankin Scale scores of 0–1 were demonstrated in 80 subjects.CONCLUSIONSPipeline embolization is safe and effective in the treatment of complex large and giant aneurysms of the intracranial internal carotid artery. Unlike more traditional endovascular treatments, flow diversion results in progressive vascular remodeling that leads to complete aneurysm obliteration over longer-term follow-up without delayed aneurysm recanalization and/or growth.Clinical trial registration no.: NCT00777088 (clinicaltrials.gov)

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

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.

We describe a case of a ruptured basilar bifurcation aneurysm that thrombosed during preparation for endovascular therapy as a complication of diagnostic angiogaphy, and showed a favorable evolution during long-term follow-up. Endogenous thrombosis of ruptured, non giant aneurysms is uncommon. The persistence of occlusion over time in such cases is not well established. Two weeks after rupture, a 6 × 8 mm basilar bifurcation aneurysm was referred for endovascular treatment. During preparation for endovascular coil occlusion, without having any endovascular material at the level of the basilar artery, a complete thrombotic occlusion of the basilar bifurcation and aneurysm was observed. Given the good collateral circulation for both posterior cerebral arteries no thrombolysis was undertaken. The early follow-up of seven days, three and six months showed a complete recanalization of the basilar artery and remodeling of the basilar bifurcation. The 20 months imaging follow-up demonstrated a small aneurysm regrowth at the prevoius location that remained stable during the follow-up of seven years. Unchanged biological and hemodynamic characteristics. however, may pose an elevated risk of a new aneurysm formation over time, making long-term imaging follow-up, and in case of progression, aneurysm occlusion necessary for the patient.

BACKGROUND AND PURPOSE: Aneurysm treatment by intrasaccular packing has been associated with a relatively high rate of recurrence. The use of mesh tubes has recently gained traction as an alternative therapy. This article summarizes the midterm results of using an endoluminal sleeve, the PED, in the treatment of aneurysms. MATERIALS AND METHODS: A total of 19 wide-neck aneurysms were treated in 18 patients: 10 by implantation of PEDs alone and 9 by a combination of PED and coils. Angiographic and clinical results were recorded immediately and at 6 months following treatment. RESULTS: Immediate angiographic occlusion was achieved in 4 and flow reduction, in another 15 aneurysms. Angiography at 6 months demonstrated complete occlusion in 17 and partial filling in 1 of 18 patients. There was no difference between coil-packed and unpacked aneurysms. Of 28 side branches covered by ≥1 device, the ophthalmic artery was absent immediately in 1 and at 6 months in another 2 cases. One patient experienced abrupt in-stent thrombosis resulting in a transient neurologic deficit, and 1 patient died due to rupture of a coexisting aneurysm. All giant aneurysms treated with PED alone were demonstrated by follow-up cross-sectional imaging to have involuted by 6 months. CONCLUSIONS: Treatment of large, wide-neck, or otherwise untreatable aneurysms with functional reconstruction of the parent artery may be achieved with relative safety using dedicated flow-modifying devices with or without adjunctive use of intrasaccular coil packing.

Háttér és célkitűzés: A percutan vertebroplastica (PVP) rendkívül hatékony módszer az osteoporoticus csigolyatörések okozta fájdalom csökkentésében. A beavatkozás után azonban a betegek egy része újabb kompressziós törést szenved. A vizsgálat célja az újabb törések gyakoriságának felmérése, valamint a PVP okozati szerepének becslése volt a kezelt betegcsoportban. Betegek és módszer: A retrospektív vizsgálatban áttekintettük az 5 és fél év alatt, csontritkulás talaján csigolyatörést szenvedett és PVP-vel kezelt, egymást követő betegek adatait. A vizsgálati csoportot a teljes populáció azon tagjai alkották, akik a csigolyastabilizáció után újabb törést szenvedtek. A vizsgálat elsődleges végpontja a PVP után kialakult újabb törések előfordulásának gyakorisága volt. A másodlagos végpontot a korábban kezelt csigolyákkal szomszédos szegmentumokban, 90 napon belül kialakult újabb törések képezték, ugyanis ebben a csoportban feltételezhető leginkább a PVP biomechanikai kiváltó szerepe. Eredmények: Összesen 396 beteget kezeltünk PVP-vel osteoporoticus csigolyatörés miatt. Az átlagéletkor 68±11 év volt. A betegek 77%-a nő. Összesen 73 beteg szenvedett a PVP után újabb törést (vizsgálati csoport), amely a teljes populáció 18,4%-át képezte. Ebben a csoportban egy főre átlagosan 3,8 csigolyatörés jutott. A PVP-vel szomszédos törések szignifikánsan gyakrabban fordultak elő, mint a távoli szegmentumot érintő fracturák. Összesen 44 beteg szenvedett szomszédos csigolyatörést a PVP utáni 90 napon belül, ők a teljes populáció 11%-át képviselték. A teljes populációhoz viszonyítva ebben a csoportban szignifikánsan kevesebb volt a férfi. Következtetés: PVP után közel minden ötödik betegnek van arra esélye, hogy újabb törést szenvedjen, azonban a korábban elvégzett csigolyastabilizációnak valószínűleg csak minden tizedik betegnél lesznek biomechanikai következményei, egy újabb fractura formájában. A legnagyobb kockázatúak a több törést szenvedett, súlyos csontritkulásban szenvedő nőbetegek.

Introduction: Despite the high effectiveness of stent-retrievers in ELVO, half of the patients remained functionally dependent (mRS≥3) after 90-days. Beyond futile recanalizations, variable endoluminal damage caused by stent-retrievers may contribute to reperfusion injury, and recruit iniflammatory cell infiltration. The goal of this study was to assess a less traumatic endovascular approach in combination with a novel shear activated-nanotherapeutic (SA-NT) that releases r-tPA when exposed to high levels of hemodynamic stress. Hypothesis: SA-NT treatment coupled with temporary endovascular bypass provides high recanalization rates while reducing vascular injury. Methods: a rabbit carotid vessel occlusion model was used. We evaluated angiographic recanalization with stent-bypass alone, intra-arterial delivery of soluble r-tPA alone, or stent-bypass combined with two doses (2 and 20 mg r-tPA) of intra-arterial infusion of either the SA-NT or soluble r-tPA. Vascular injury was compared against stent-retriever thrombectomy by assessing the level of damage on histology. Results: Shear-targeted delivery of r-tPA using the SA-NT resulted in the highest rate of complete recanalization when compared to controls (p=0.0011). SA-NT (20mg) had a higher likelihood of obtaining complete recanalization (mTICI:3) as compared to stent-bypass alone (OR: 65.019,95%CI:[1.77,>1000], p=0.0231), intra-arterial r-tPA alone (OR: 65.019, 95% CI [1.77,>1000], p=0.0231), or stent-bypass with soluble r-tPA (2 mg) (OR: 18.78, 95%CI [1.28,275.05], p=0.0322) (Figure). Histologically, there was significantly less vascular injury using a stent-bypass as compared to stent-retriever procedure (OR 12.97, 95%CI [8.01,21.02], p Conclusion: Nanoparticle-based thrombolytic therapy combined with stent-bypass achieves high rates of complete (mTICI:3) recanalization. This technology reduces vascular trauma as compared to stent-retriever thrombectomy

Background and Purpose— The goal of this study is to combine temporary endovascular bypass (TEB) with a novel shear-activated nanotherapeutic (SA-NT) that releases recombinant tissue-type plasminogen activator (r-tPA) when exposed to high levels of hemodynamic stress and to determine if this approach can be used to concentrate r-tPA at occlusion sites based on high shear stresses created by stent placement. Methods— A rabbit model of carotid vessel occlusion was used to test the hypothesis that SA-NT treatment coupled with TEB provides high recanalization rates while reducing vascular injury. We evaluated angiographic recanalization with TEB alone, intra-arterial delivery of soluble r-tPA alone, or TEB combined with 2 doses of intra-arterial infusion of either the SA-NT or soluble r-tPA. Vascular injury was compared against stent-retriever thrombectomy. Results— Shear-targeted delivery of r-tPA using the SA-NT resulted in the highest rate of complete recanalization when compared with controls ( P =0.0011). SA-NT (20 mg) had a higher likelihood of obtaining complete recanalization as compared with TEB alone (odds ratio 65.019, 95% confidence interval 1.77, >1000; P =0.0231), intra-arterial r-tPA alone (odds ratio 65.019, 95% confidence interval 1.77, >1000; P =0.0231), or TEB with soluble r-tPA (2 mg; odds ratio 18.78, 95% confidence interval 1.28, 275.05; P =0.0322). Histological analysis showed circumferential loss of endothelium restricted to the area where the TEB was deployed; however, there was significantly less vascular injury using a TEB as compared with stent-retriever procedure (odds ratio 12.97, 95% confidence interval 8.01, 21.02; P Conclusions— A novel intra-arterial, nanoparticle-based thrombolytic therapy combined with TEB achieves high rates of complete recanalization. Moreover, this approach reduces vascular trauma as compared with stent-retriever thrombectomy.

OBJECT Neuroophthalmological morbidity is commonly associated with large and giant cavernous and supraclinoid internal carotid artery (ICA) aneurysms. The authors sought to evaluate the neuroophthalmological outcomes after treatment of these aneurysms with the Pipeline Embolization Device (PED). METHODS The Pipeline for Uncoilable or Failed Aneurysms (PUFS) trial was an international, multicenter prospective trial evaluating the safety and efficacy of the PED. All patients underwent complete neuroophthalmological examinations both before the PED procedure and at a 6-month follow-up. All examinations were performed for the purpose of this study and according to study criteria. RESULTS In total, 108 patients were treated in the PUFS trial, 98 of whom had complete neuroophthalmological follow-up. Of the patients with complete follow-up, 39 (40%) presented with a neuroophthalmological baseline deficit that was presumed to be attributable to the aneurysm, and patients with these baseline deficits had significantly larger aneurysms. In 25 of these patients (64%), the baseline deficit showed at least some improvement 6 months after PED treatment, whereas in 1 patient (2.6%), the deficits only worsened. In 5 patients (5%), new deficits had developed at the 6-month follow-up, while in another 6 patients (6%), deficits that were not originally assumed to be related to the aneurysm had improved by that time. A history of diabetes was associated with failure of the baseline deficits to improve after the treatment. The aneurysm maximum diameter was significantly larger in patients with a new deficit or a worse baseline deficit at 6 months postprocedure. CONCLUSIONS Patients treated with the PED for large and giant ICA aneurysms had excellent neuroophthalmological outcomes 6 months after the procedure, with deficits improving in most of the patients, very few deficits worsening, and few new deficits developing.

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.

BACKGROUND AND PURPOSE: Alleviation of aneurysm induced mass effect has been difficult with both conventional endovascular and surgical techniques. Our aim was to study the efficacy of endovascular flow modification on aneurysm-induced mass effect and compression syndrome, as demonstrated by cross-sectional imaging studies and clinical follow-up. MATERIALS AND METHODS: Thirty aneurysms larger than 10 mm were treated by flow diversion alone and previously had undergone pre- and posttreatment cross-sectional imaging. Pretreatment MR imaging or contrast CT, follow-up angiography at 6 months, and follow-up MR imaging studies between 6 and 18 months were retrospectively analyzed. The neurologic and neuro-ophthalmologic statuses of all patients were recorded before treatment and at the time of follow-up cross-sectional imaging. RESULTS: At 6 months, 28 aneurysms were completely occluded, 1 had a neck remnant, and 1 had residual filling on angiography. Between 6 and 18 months, 3 aneurysms decreased in size and 27 completely collapsed as demonstrated on MR imaging. Before treatment, 6 patients had vision loss, 10 had double vision due to a third or sixth nerve palsy or both, and 1 had hemiparesis due to brain stem compression. On MR imaging follow-up, vision loss had either improved or resolved in all except 1 patient, double vision had resolved completely (7/10) or partially (3/10), and the patient with brain stem compression became asymptomatic. There was no bleeding observed in this series. One parent artery thrombosis resulted in a major infarct. CONCLUSIONS: Endovascular flow diversion is a highly effective technique for resolving radiologic mass effect and clinical compression syndromes.

To evaluate the safety and effectiveness of the Pipeline Embolization Device (PED; ev3/Covidien, Irvine, Calif) in the treatment of complex intracranial aneurysms.The Pipeline for Uncoilable or Failed Aneurysms is a multicenter, prospective, interventional, single-arm trial of PED for the treatment of uncoilable or failed aneurysms of the internal carotid artery. Institutional review board approval of the HIPAA-compliant study protocol was obtained from each center. After providing informed consent, 108 patients with recently unruptured large and giant wide-necked aneurysms were enrolled in the study. The primary effectiveness endpoint was angiographic evaluation that demonstrated complete aneurysm occlusion and absence of major stenosis at 180 days. The primary safety endpoint was occurrence of major ipsilateral stroke or neurologic death at 180 days.PED placement was technically successful in 107 of 108 patients (99.1%). Mean aneurysm size was 18.2 mm; 22 aneurysms (20.4%) were giant (25 mm). Of the 106 aneurysms, 78 met the study's primary effectiveness endpoint (73.6%; 95% posterior probability interval: 64.4%-81.0%). Six of the 107 patients in the safety cohort experienced a major ipsilateral stroke or neurologic death (5.6%; 95% posterior probability interval: 2.6%-11.7%).PED offers a reasonably safe and effective treatment of large or giant intracranial internal carotid artery aneurysms, demonstrated by high rates of complete aneurysm occlusion and low rates of adverse neurologic events; even in aneurysms failing previous alternative treatments.

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

We describe an interesting case of trigeminocardiac reflex (TCR) caused by selective angiography of the middle meningeal artery (MMA). A 28-year-old woman presented with a symptomatic meningioma. Preoperative tumour embolisation was performed. In the procedure, when selective MMA angiography was done with Omnipaque 300 mg I/mL for 3 mL by manual injection, the patient complained of flashing lights in her eye followed by vomiting and bradycardia down to 40 bpm without increased intracranial pressure signs. On selective MMA angiography, the choroidal crescent and arteries of the periorbital region were opacified by anastomosis from the MMA via the meningo-ophthalmic artery. We diagnosed that her symptoms were caused by selective MMA angiography leading to high pressure stimulation towards the ophthalmic nerve innervation around the orbit as a TCR. We suggest that the operator should be prepared to manage TCR during treatment with expected selective MMA angiography, and gentle low pressure contrast injection should be attempted.

Introduction In vitro studies have shown that Pipeline Embolization Device+Shield Technology (Shield) with a surface modification of a 3 nm thick modified phosphorylcholine is less thrombogenic. 1 We hypothesize that Shield has less thrombus formation in vivo as compared to Pipeline Embolization Devices (PED) regardless of dual antiplatelet therapy (DAPT). Methods Forty rabbits with elastase induced aneurysms were randomly assigned to receive a Shield or PED. For each device, half of the animals received DAPT. In each of the four groups, 10 animals were enrolled for a period of 30 days. Herein, we report on 32 animals that have reached the study endpoint to date. Animals that received DAPT (10 mg/kg each of aspirin and clopidogrel) were started a 5 days prior to implant and continued until the endpoint at 30 days. At the time of implant optical coherence tomography (OCT, Dragonfly, St Jude) was performed before and after angioplasty, and repeated at terminal follow-up. Thrombus formation was assessed at 4 locations along the implant (distal end, at the level of the vertebral artery, at the aneurysm neck, and at the proximal end) as present or absent. Aneurysm occlusion was assessed on digital subtraction angiography after 30 days and according to the scale of Darsaut et al. 2 Results Baseline characteristics (e.g., aneurysm size, neck size, parent vessel diameter) were not different between the four groups (p > 0.1). Animals receiving DAPT had a significant reduction in PRU values (69 ± 28 vs 247 ± 41, p 0.05). The Shield was more likely to have no thrombus or thrombus only at one of the four locations as compared to PED (OR 0.10 95% CI 0.02–0.56, p = 0.01). There was no difference in thrombus at the four locations as a function of DAPT (p > 0.05). There was no dependence on aneurysm occlusion on the device used or PRU value; however, achieving complete or near complete occlusion was negatively and marginally correlated with the aneurysm neck size (Spearman’s rho = 0.314; p = 0.049). Conclusion The hypothesis that Shield technology reduces acute thrombus formation regardless of DAPT has been confirmed in vivo using OCT. References 1 G Girdhar et al . J Thromb Thrombolysis 2015; 40 :437–4432. 2 TE Darsaut, et al . AJNR . 2012; 33 :2004–2009 Disclosures M. Marosfoi: None. E. Langan: None. S. Vedantham: None. F. Clarencon: None. R. King: None. J. Wainwright: 5; C; Medtronic Neurovascular. M. Gounis: 1; C; Medtronic Neurovascular. A. Puri: 1; C; Medtronic Neurovascular. 2; C; Medtronic Neurovascular.

Introduction The BRAVO flow diverter (Codman Neurovascular) is a variable count, braided implant made of nitinol wires for optimized wall apposition, with platinum wires for radiopacity. The implant also has laser-cut nitinol expansion rings at each end for instant opening and accurate placement. We hypothesize that there are no differences in aneurysm occlusion rates between the BRAVO and reference flow diverter (Pipeline Embolization Device, PED). Materials and methods Twenty-four rabbits with saccular, elastase induced aneurysms were randomly assigned to receive a BRAVO or PED. Inclusion criteria for implant were the origin of the left common carotid artery at the brachiocephalic trunk, presence of an aneurysm and subclavian artery at the origin of the vertebral artery having a diameter 1 namely, 0 = no change, 1 ≤ 50% volume reduction, 2 ≥ 50% volume reduction, 3 = aneurysm filling confined to the neck, and 4 = complete occlusion. Terminal angiography and histological analysis will be performed at 180 days. All animals were on dual antiplatelet therapy (DAPT, 10 mg/kg each of aspirin and clopidogrel) beginning at least 4 days before implant and continued until 30 days after implant. Results Baseline characteristics (e.g., aneurysm size, neck size, PRU, parent vessel diameter) were not different between the two groups (p > 0.05). Clopidogrel had a significant effect on PRU (231 ± 38 at baseline vs 56 ± 25 after DAPT, p 4.5 mm. Another animal in the PED group was excluded due to distal migration of the device following deployment leading to incomplete coverage of the aneurysm neck. All remaining devices were accurately deployed. Longitudinal imaging studies have shown progressive healing of the aneurysms for both devices, with approximately half of the aneurysms completely occluded at 90 days (Figure 1). There are no differences between the occlusion rates of the devices. Conclusion A new flow diverter has been designed to enable accurate placement with self-expanding rings at both ends of the device. This new generation device has equivalent occlusion rates in a rabbit model of saccular aneurysms as compared to the reference device. Reference 1 Darsaut TE, et al . AJNR 2012; 33 :2004–2009. Disclosures M. Marosfoi: None. E. Langan: None. R. King: None. F. Clarencon: None. I. Lylyk: None. O. Brooks: None. R. Slazas: 5; C; Codman Neurovascular. A. Puri: 2; C; Codman Neurovascular. M. Gounis: 1; C; Codman Neurovascular. 2; C; Codman Neurovascular.

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.

Introduction The use of clot retrievers during mechanical endovascular treatment of acute ischemic stroke can cause clot fragmentation with the release of distal emboli. It was our hypothesis that the risk of embolic shower may potentially be altered using the Embolus Retriever with Interlinked Cages (ERIC®) thrombectomy system. The objective of this study was the characterization of distal emboli generated during ERIC® thrombectomy device use as a function of access approach. Materials and methods A hard, inelastic clot was prepared and injected into an anatomically correct circle of Willis (CoW) replica to form a middle cerebral artery occlusion. Thrombectomy was conducted per the manufacturer’s instructions in four different groups (n = 10), each exploring different variables. In group 1, thrombectomy was performed using the ERIC ® through an 8 F balloon guide catheter (BGC) positioned at the cervical ICA (ERIC®+BGC). In group 2, thrombectomy was performed using the ERIC® in conjunction with thromboaspiration via a 6 F Sofia intermediate catheter at the origin of the MCA (ERIC®+SOFIA). In group 3, thrombectomy was performed using the Solitaire in conjunction with thromboaspiration via a 6 F Sofia intermediate catheter at the origin of the MCA (Solitaire+SOFIA). Group 4 used the same setup as group 2 with the addition of proximal ICA flow arrest using a BGC during clot removal (ERIC®+SOFIA+BGC). Emboli smaller than 1000 µm was characterized using the Coulter Principle. The primary endpoints were the size and quantity of the clot fragments generated during the procedure and the secondary endpoints were the flow recanalization rate and time to recanalization. Results Formation of large emboli greater than 1000 μm in size occurred in 2 out of 10 cases in the ERIC®+BGC group, versus 7, 6 and 5 of 10 experiments with the ERIC®+SOFIA, Solitaire+SOFIA, ERIC®+SOFIA+BGC groups, respectively. The ERIC®+BGC group marginally reduced the number of emboli having a diameter >200 μm (p = 0.064), with a total of 5 particles, as compared to the ERIC®+Sofia, Solitaire+Sofia, and ERIC®+Sofia+BGC groups that produced 20, 17 and 16 fragments >200 μm, respectively. On average, in the size range between 100–200 μm and 50–100 μm, ERIC®+Sofia showed a trend to reduce clot fragments as compared with the other 3 treatment strategies; however, these results were not statistically significant (p > 0.05). There were no significant differences in particle number between any of the groups for particles with size Conclusion Based on this preliminary study, it is our conclusion that the techniques of ERIC®+BGC, ERIC®+Sofia, Solitaire+Sofia, and ERIC®+SOFIA+BGC are all similar with regard to clot fragmentation. Combining all particulates in the most dangerous range (>200 μm), there was a marginal reduction in the number of distal emboli with the use of ERIC® and BGC (p = 0.064). Disclosures J. Chueh: None. M. Marosfoi: None. E. Langan: None. A. Puri: 1; C; Medtronic Neurovascular, Stryker Neurovascular. 4; C; InNeuroCo. M. Gounis: 1; C; National Institutes of Health, Codman Neurovascular, Stryker Neurovascular, Microvention, Medtronic Neurovascular, Philips Healthcare, InNeuroCo, Neuronal Protection Systems, the Wyss Institute, Silk Road. 2; C; Codman Neurovascular, Stryker Neurovascular. 4; C; InNeuroCo.

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 AND PURPOSE: Cerebral aneurysms are preferentially located at arterial curvatures and bifurcations that are exposed to major hemodynamic forces, increasingly implicated in the life cycle of aneurysms. By observing the natural history of aneurysm formation from its preaneurysm state, we aimed to examine the hemodynamic microenvironment related to aneurysm initiation at certain arterial segments later developing an aneurysm. MATERIALS AND METHODS: The 3 patients included in the study underwent cerebral angiography with 3D reconstruction before a true aneurysm developed. The arterial geometries obtained from the 3D-DSA models were used for flow simulation by using finite-volume modeling. The WSS and SWSSG at the site of the future aneurysm and the flow characteristics of the developed aneurysms were analyzed. RESULTS: The analyzed regions of interest demonstrated significantly increased WSS, accompanied by an increased positive SWSSG in the adjacent proximal region. The WSS reached values of >5 times the temporal average values of the parent vessel, whereas the SWSSG approximated or exceeded peaks of 40 Pa/mm in all 3 cases. All patients developed an aneurysm within 2 years, 1 of which ruptured. CONCLUSIONS: The results of this hemodynamic study, in accordance with the clinical follow-up, suggest that the combination of high WSS and high positive SWSSG focused on a small segment of the arterial wall may have a role in the initiation process of aneurysm formation.