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Introduction: Bifurcation aneurysms represent an ongoing endovascular challenge with a variety of techniques and devices designed to address them. We present our multicenter series of the pCONUS2 and pCONUS2 HPC devices when treating bifurcation aneurysms., Methods: We performed a retrospective review of our prospectively maintained databases at 3 tertiary neurointerventional centers to identify all patients who underwent coil embolization with the pCONUS2 or pCONUS2 HPC device between February 2015 and August 2021. We recorded baseline demographics, aneurysm data, complications, immediate and delayed angiographic results., Results: We identified 55 patients with 56 aneurysms, median age 63 years (range 42-78 years), 67.3% female (n = 37). The commonest aneurysm location was the MCA bifurcation (n = 40, 71.4%). Average dome height was 8.9 ± 4.2 mm (range 3.2-21.5 mm), average neck width 6.4 ± 2.5 mm (range 2.6-14 mm), and average aspect ratio 1.3 ± 0.6 (range 0.5-3.3). The pCONUS2 was used in 64.3% and the pCONUS2 HPC in 35.7%. The procedural technical success rate was 98.2%. Intraoperative complications occurred in 5 cases (8.9%), 4 of which were related to the coils with partial thrombus formation on the pCONUS2 HPC seen in 1 case that was resolved with heparin. In relation to the procedure and treatment of the aneurysm the overall permanent morbidity was 1.8% (n = 1/55) and mortality 0%. Delayed angiographic follow-up (48 aneurysms) at median 12 months postprocedure (range 3-36 months) demonstrated adequate occlusion of 83.4% of aneurysms., Conclusion: The pCONUS2 and pCONUS2 HPC devices carry a high technical success rate, low complication and retreatment rate, and good rates of adequate occlusion. Larger prospective confirmatory studies are required., (© 2022. The Author(s).)

Background and Purpose: Recently, avant-garde combinations of ancillary devices as an adjunct to coil embolization for acutely ruptured and wide-necked cerebral aneurysms have emerged. This study sought to investigate the feasibility, safety and durability of the simultaneous combination of temporary neck-bridging devices plus balloon-assisted coiling (BAC) to treat acutely ruptured and wide-necked cerebral aneurysms., Methods: A retrospective review was performed of patients with ruptured and wide-necked intracranial bifurcation aneurysms treated with temporary stent plus balloon-assisted coiling. Anatomical features, technical details, intraprocedural complications, clinical and angiographic results were reviewed. Preprocedural and follow-up clinical statuses were evaluated using the modified Rankin scale (mRS)., Results: A total of 21 patients (mean age 54.5 years, range 37-72 years) were identified. The immediate postprocedural angiography revealed complete aneurysm occlusion in 85.7% (18/21) of the cases. A periprocedural complication developed in 9.5% of the cases. There was no mortality in this study. The permanent morbidity rate was 4.7%. Long-term follow-up angiography was performed in 18 of 21 patients (85.7%) (the mean follow-up period was 21 months). The rate of complete aneurysm occlusion at final follow-up was 89.4%., Conclusion: The results of this study confirmed that temporary stent plus balloon-assisted coiling is a durable and relatively safe endovascular technique for the treatment of ruptured wide-necked bifurcation aneurysms located in both the posterior and anterior cerebral circulation., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Background: Endovascular treatment (EVT) has strong evidence for its effectiveness in treatment of acute ischemic stroke (AIS); however, up to half of the patients who undergo EVT still do not have good functional outcomes. Various prethrombectomy radiological factors have been shown to be associated with good clinical outcomes and may be the key to better functional outcomes, reduced complications, and reduced mortality. In this paper, we reviewed the current literature on these imaging parameters so they can be employed to better estimate the probability of procedural success, therefore allowing for more effective preprocedural planning of EVT strategies. We reviewed articles in the literature related to imaging factors which have been shown to be associated with EVT success. The factors which are reviewed in this paper included: anatomical factors such as 1) the type of aortic arch and its characteristics, 2) the characteristics of the thrombus such as length, clot burden, permeability, location, 3) the middle cerebral artery features including the tortuosity and underlying intracranial stenosis, 4) perfusion scans estimating the volume of infarct and the penumbra and 5) the effect of collaterals on the procedure. The prognostic effect of each factor on the successful outcome of EVT is described. The identification of preprocedural thrombectomy imaging factors can help to improve the chances of recanalization, functional outcomes, and mortality. It allows the interventionist to make time-sensitive decisions in the treatment of acute ischemic stroke., (© 2021. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Adenosine induced cardiac standstill has been used intraoperatively for both aneurysm and arteriovenous malformation (AVM) surgery and embolization. We sought to report the results of adenosine induced cardiac standstill as an adjunct to endovascular embolization of brain AVMs., Material and Methods: We retrospectively identified patients in our prospectively maintained database to identify all patients since January 2007 in whom adenosine was used to induce cardiac standstill during the embolization of a brain AVM. We recorded demographic data, clinical presentation, Spetzler Martin grade, rupture status, therapeutic intervention and number of embolization sessions, angiographic and clinical results, clinical and radiological outcomes and follow-up information., Results: We identified 47 patients (22 female, 47%) with average age 42 ± 17 years (range 6-77 years) who had undergone AVM embolization procedures using adjunctive circulatory standstill with adenosine. In total there were 4 Spetzler Martin grade 1 (9%), 9 grade 2 (18%), 15 grade 3 (32%), 8 grade 4 (18%), and 11 grade 5 (23%) lesions. Of the AVMs six were ruptured or had previously ruptured. The average number of embolization procedures per patient was 5.7 ± 7.6 (range 1-37) with an average of 2.6 ± 2.2 (range 1-14) embolization procedures using adenosine. Overall morbidity was 17% (n = 8/47) and mortality 2.1% (n = 1/47), with permanent morbidity seen in 10.6% (n = 5/47) postembolization. Angiographic follow-up was available for 32 patients with no residual shunt seen in 26 (81%) and residual shunts seen in 6 patients (19%). The angiographic follow-up is still pending in 14 patients. At last follow-up 93.5% of patients were mRS ≤2 (n = 43/46)., Conclusion: Adenosine induced cardiac standstill represents a viable treatment strategy in high flow AVMs or AV shunts that carries a low risk of mortality and permanent neurological deficits., (© 2021. The Author(s).)

Purpose: Treatment of wide-necked intracranial aneurysms using the Woven Endobridge (WEB) device has become broadly accepted. Feared complications with the potential of increased poor clinical outcome include dislocations and migration of the device. This study was carried out to determine the effectiveness of a variety of different strategies to rescue migrated WEB devices., Methods: In a porcine model, WEB devices of different sizes (SL [single layer] 3.5 × 2mm and SL 4.0 × 3 mm, SL 8 × 5 mm and SLS 8 mm [single layer spherical]) were placed into both the subclavian and axillary arteries. A total of 32 rescue maneuvers (8 per rescue device) were performed. Small WEBs were rescued using reperfusion catheters (RC) (SOFIA Plus and JET 7), larger WEBs were rescued using dedicated rescue devices (Microsnare and Alligator). Rescue rates, times, attempts and complications were assessed., Results: Rescue attempts of migrated WEBs were successful in all cases (100%). Rescue time (p = 0.421) and attempts (p = 0.619) of small WEBs using RCs were comparable without significant differences. Aspiration alone was not successful for larger WEBs. Rescue of larger WEBs was slightly faster (122.75 ± 41.15 s vs. 137.50 ± 54.46 s) with fewer attempts (1 vs. 1.37) when using the Microsnare compared to the Alligator device. Complications such as entrapment of the WEB in the RCs, vasospasm, perforation, or dissection were not observed., Conclusion: Rescue of migrated WEB devices is a feasible and effective method and 100% successful rescue rates and appropriate rescue times can be achieved for small WEBs using RCs and for larger WEBs using dedicated rescue devices (Microsnare and Alligator).

Background and Purpose: Free floating thrombus (FFT) is a rare condition. The optimal treatment strategy is yet to be determined although medical management with anticoagulation is the mainstay. This article reports experience of treating FFT with carotid stenting., Methods: A retrospective analysis of a prospectively maintained database was performed to identify all patients with FFT treated with carotid stenting. For each patient the demographic data, clinical presentation, location of the thrombus, type of stent and use of adjunctive devices, e.g. balloon guide catheters, clinical and radiological follow-up information as well as complications were recorded., Results: A total of 7 patients, 4 female, with mean age of 55.6 ± 14.5 years were identified. The median National Institutes of Health Stroke Scale (NIHSS) was 7 (range 0-13) at presentation. Free floating thrombus was seen on the left in the majority of cases (n = 6, 85.7%). None of the patients had intracranial large vessel occlusion. The FFT was located in the CCA in 2 cases (28.6%) and the proximal ICA in the remaining 5 cases (71.4%). The Wallstent was used in 5 patients and a cGuard stent used in 2 patients. In 1 patient 2 overlapping stents were used but a single stent was used in the remaining patients. In 6 cases a distal filter wire was used and in 2 cases a balloon guide catheter was used as embolic protection. There were no intraoperative complications and no cases of distal clot migration or intracranial large vessel occlusion during the procedure. At last follow-up (n = 7) 6 patients were recorded as modified Rankin Scale (mRS) ≤2 and 1 patient was mRS 3., Conclusion: Free floating thrombus of the carotid arteries can be managed with stenting.

Purpose: Mechanical thrombectomy using the Solitaire device has become a standard treatment of ischemic stroke due to large vessel occlusions. Inadvertent detachment is a feared complication, which is associated with poor clinical outcome. The aim of this experimental study was to assess in a porcine model the feasibility and effectiveness of rescuing detached Solitaire devices using different stent retrievers., Methods: Solitaire FR devices (4 × 15/20 mm and 6 × 20/30 mm) were placed in the axillary artery of pigs. By means of 3 different stent retrievers (Trevo ProVue; EmboTrap II revascularization device; 3D revascularization device) a total of 24 rescue maneuvers (8 per retriever) were performed by deploying the retrievers within the deployed Solitaire devices and trapping parts of the Solitaire within the microcatheter. Rescue rates, rescue time and complications were assessed., Results: Overall stentectomy of the Solitaire devices was successful in all cases (100%). Time of rescue was comparable using the applied stent retrievers (Trevo ProVue; EmboTrap II revascularization device; 3D revascularization device). Complications, such as entrapment of the Solitaire-retriever complex at the intermediate catheter, Solitaire migration, vasospasm, perforation, or dissection were not observed., Conclusion: Stentectomy of inadvertently detached Solitaire devices using different stent retrievers is a feasible and effective method. Rescue rates and times with the Trevo ProVue, EmboTrap II and 3D revascularization device were comparable.

Background and Purpose: Endosaccular flow disruption is a recognized treatment options for treating both unruptured and ruptured aneurysms. The Contour device is designed to target the neck of an aneurysm and cause flow disruption within the aneurysm hence promoting thrombosis and neo-endothelialization at the neck. This article presents initial experiences with the Contour., Methods: The prospectively maintained database was retrospectively reviewed to identify patients treated with the Contour device. Demographic data, aneurysm characteristics, clinical result, and clinical and radiological follow-up information were recorded., Results: The review identified 3 patients (2 female), with 3 unruptured aneurysms, of average age 67 ± 8.7 years (range 62-77 years). The aneurysms were all located in the anterior circulation including one pericallosal, one at the A1-2 junction and one on the ICA bifurcation. The mean average dome height was 7.6 ± 0.62 mm (range 7.1-8.3 mm), dome width 5.7 ± 2 mm (range 3.5-7.5 mm), and neck width 3.6 ± 0.95 mm (range 2.5-4.2 mm). At follow-up angiography two of the aneurysms were completely occluded and one device had displaced into the aneurysm sac due to inappropriate positioning of the device. Of the patients one had minor stroke during the postoperative period but returned to baseline neurology. All patients were mRS 0 at last follow-up., Conclusion: The Contour is a promising new aneurysm occlusion device. Further studies with longer term follow-up are required to determine the efficacy of this novel device.

Background and Purpose: The use of flow diverters to treat aneurysms arising from small caliber parent vessels has been reported. This article reports the results of the first in experiences with the p48MW (p48 Movable Wire) in humans, a device specifically designed to target vessels 1.75-3 mm in diameter., Methods: This monocentric study retrospectively reviewed the prospectively maintained database to identify all patients treated with the p48MW device between January 2017 and January 2019 at this institution. Patient demographics, aneurysm characteristics, angiographic and clinical follow-up were recorded as well as complications., Results: A total of 25 patients (20 female) with an average age of 55 ± 12.9 years (range 34-84) with 25 aneurysms were identified. The majority of the aneurysms was located in the anterior circulation (19/25, 76%). The average aneurysm dome width was 3.98 ± 3.6 mm (range 1.2-13 mm). Complete occlusion was seen in 18/24 (75%) aneurysms with neck remnants in 1/24 (4.2%) and continued aneurysm filling seen in the remaining cases (5/24, 20.8%). Adequate occlusion was seen in 79.2% of aneurysms (Raymond Roy Classification [RRC] grade I or II) during the follow-up period. There was a single technical complication with inappropriate deployment of the first p48MW. There was a single clinical complication (4%); however, the patient made a complete recovery (modified Rankin Scale [mRS] 0) and one patient died secondary to uncontrollable status epilepticus following acute subarachnoid hemorrhage unrelated to the treatment., Conclusion: The p48MW is safe and effective for the treatment of aneurysms including those arising from distal vessels.

Background and Purpose: The p64 is a flow modulation device designed to be used in endovascular treatment of intracranial aneurysms. There is limited data on the long-term effectiveness of the device. This study sought to determine the safety and long-term efficacy of this device., Methods: A retrospective review of a prospectively maintained database was performed to identify all patients treated with a p64 between March 2015 and November 2018 at University Hospital St. Ivan Rilski. Anatomical features, intraprocedural complications, clinical, and angiographic outcomes were also taken into account and reviewed., Results: A total of 72 patients with 72 aneurysms who met the inclusion criteria were identified. Device placement was successful in all patients. Follow-up angiographic imaging at 6 months showed complete occlusion (O'Kelly-Marotta scale [OKM] D) in 55 (76.3%) patients, subtotal aneurysmal filling (OKM B) in 10 (13.8%) patients, and neck remnant (OKM C) in 7 (9.7%) patients. Catheter angiography at 12 months was available for 70 patients (97.2%) and of these patients 91.4% of the aneurysms were completely occluded (OKM D) (64/72). Delayed angiography at 24 months was available for 68 patients (94.4%) and of these 98.5% (67/68) had completely occluded aneurysms. A 36-month angiography was available for 61 patients (84.4%) by which point all aneurysms had been completely occluded (100%). Permanent morbidity due to delayed aneurysmal rupture occurred in one patient (1.38%). The mortality rate was 0%. Self-limiting mild intimal hyperplasia was seen in 2 patients (2.72%)., Conclusion: Treatment of intracranial aneurysms with a p64 flow modulation device is safe and effective with a high success rate and only infrequent complications.

Background: Studies have shown that the modified thrombolysis in cerebral ischemia (mTICI) 2B score is associated with better functional outcome; however, 50-99% reperfusion is a large range and there may be factors which can differentiate this further. The effects of very late leptomeningeal collaterals (VLLC) on mTICI-2B patients were studied., Method: A prospectively collected registry of anterior circulation AIS patients treated with the EmboTrap revascularization device from 2013 to 2016 was evaluated. Imaging parameters and timings, including the mTICI score were verified by an external core laboratory blinded to the clinical data. The final angiogram was examined for the appearance of VLLC in predicting 3‑month outcomes including excellent functional outcomes, defined as modified Rankin scale (mRS) 0-1, bleeding risk and mortality., Results: A total of 177 consecutive anterior circulation stroke patients were included in the analysis. Of these 94 (53.1%) achieved only mTICI-2B reperfusion, 16/94 (17.0%) patients achieved excellent functional outcomes at 3 months and 26 (27.7%) had hyperdensity on follow-up computed tomography (CT). On univariate analysis, the presence of VLLC was inversely associated with excellent functional outcomes at 3 months and positively associated with mortality in patients with mTICI-2B reperfusion. On multivariate analysis VLLC was inversely associated with excellent outcomes (odds ratio 0.075, 95% confidence interval 0.007-0.765, P = 0.029) but not associated with mortality., Conclusion: The mTICI-2B grade may be further refined by secondary radiological markers. The VLLC sign is associated with the loss of excellent functional outcomes at 3 months. It is a simple sign to discriminate mTICI-2B into different grades but should be verified in larger populations from other centers.

Correction to: Clin Neuroradiol 2019 https://doi.org/10.1007/s00062-019-00776-2 The original version of this article unfortunately contained a mistake. The Acknowledgements were missing. The correct information is given ….

Background and Purpose: Intracranial adjacent tandem lesions of the internal carotid artery (ICA) are rare and the optimal treatment strategy is unknown. This study was carried out to determine whether a single flow diverter stent (FDS) could be successfully used to treat these lesions., Methods: The prospectively maintained database was retrospectively carried out to identify patients treated between February 2009 and February 2018 with multiple unruptured, tandem ICA aneurysms and treated with a single FDS. Demographic data, clinical presentation, aneurysm characteristics, treatment data, clinical result and clinical and radiological follow-up information were recorded., Results: A total of 69 patients (62 female, 89.8%) with average age 55 ± 14.8 years were identified. In total there were 169 aneurysms and the majority of patients (n = 47, 68.1%) had only 2 tandem aneurysms. The largest aneurysms measured 7.69 ± 5.3 mm (range 1.5-26 mm) in height, 6.64 ± 4.71 mm (range 1.5-23 mm) in width and the smaller aneurysm measured 2.61 ± 1.32 mm (range 0.8-9.5 mm) in height and 2.32 ± 1.12 mm (range 0.7-8 mm) in width. In 36 patients the p64 was used, the PED in 28 patients and Surpass in 5 patients. Follow-up was available in 54 patients (130 aneurysms). At initial follow-up (7.2 ± 4.2 months) 45 (83.3%) of the larger aneurysms and 66 (86.8%) of the smaller aneurysms were satisfactorily occluded (Raymond-Roy classification RRC 1 or 2). At delayed follow-up (18 ± 14.6 months) 48 of the larger aneurysms (88.9%) and 71 of the smaller aneurysms (93.4%) were satisfactorily occluded. There were three complications including one death., Conclusion: A single FDS can be used to successfully treat multiple tandem aneurysms of the ICA with a high rate of aneurysm exclusion and an acceptable risk profile.

Background: Approved alternatives in the guidelines for acute ischemic stroke patients who have failed intracranial thrombectomy are lacking. Primary permanent intracranial stenting was initially used in the era before thrombectomy and might still be a useful rescue treatment in acute stroke patients suffering from ongoing large vessel occlusion refractory to thrombectomy., Methods: The prospectively collected registry of patients with acute stroke caused by large vessel occlusions and treated with the emboTrap® device in Karolinska Hospital from October 2013 through March 2017 were retrospectively reviewed. Clinical outcome of non-recanalized patients with a thrombolysis in cerebral infarction (TICI) score of 0-1 after failed thrombectomy were compared with those who were treated with permanent intracranial stenting as rescue therapy. Favorable outcome was defined as modified Rankin scale 0-2., Results: The emboTrap® device was used in 201 patients. Persistent re-occlusions on withdrawal of the thrombectomy device were seen in 26 patients (13%) and of those, 12 individuals (46%) were treated with intracranial stenting. Baseline National Institutes of Health stroke scale (NIHSS), occlusion site, and onset-to-puncture time did not differ between the stenting group and the non-recanalized group. During the procedure half dose (5/12 patients) or full dose abciximab (6/12 patients), or aspirin (1/12 patient) was given intravenously immediately after stent placement. In 2 patients (17%) multiple stents were implanted. The stenting group had better functional outcomes at 3 months compared to the non-stenting group with 8/12 (66%) vs. 3/14 (21.4%, p < 0.05). Of the patients 5 (36%) in the non-stented group had died at 3 months follow-up, whereas mortality in the stenting cohort was 0% (p < 0.05) and no symptomatic intracranial hemorrhage (ICH) occurred in either group., Conclusion: Intracranial stenting after failure of recanalization with thrombectomy led to a better rate of clinical outcome than leaving the patient non-recanalized. The required antiplatelet therapy, predominantly abciximab, did not lead to additional ICH.

Background: Dural arteriovenous fistulas (DAVF) are commonly encountered lesions that can be treated both transvenously, transarterially or using a combined approach., Objective: Transvenous coil embolization of DAVF is a recognized treatment option but can be challenging. In this context this article presents clinical experience using the Kaneka ED10 ExtraSoft coils in combination with the Marathon microcatheter to treat high grade DAVF. The physical properties of these coils and the microcatheter were also determined., Material and Methods: All patients with high grade DAVF treated with the Marathon and the Kaneka ED COIL ∞10 ExtraSoft coils were retrospectively identified. The clinical presentation, location, grade of the lesion, clinical and radiological follow-up data were recorded. Bench side studies were performed to determine the physical properties of the Marathon catheter in comparison to the SL10 and Headway Duo as well the maximum width of the Kaneka pusher wire in comparison to Hypersoft, Target and Axium Prime coils., Results: A total of 8 patients with 9 DAVF with 3 Cognard 3 and 6 Cognard 4 lesions were identified. All the DAVF's were occluded either at the end of the procedure or on follow-up imaging. On bench side tests the Marathon microcatheter had the most flexible distal tip and distal shaft in comparison to the SL10 and Headway Duo. The proximal shaft of the Marathon was stiffer than the SL10. The Kaneka ED COIL ∞10 ExtraSoft had the smallest distal width and were the only coils tested that could be deployed through a Marathon microcatheter., Conclusion: The combination of the Marathon microcatheter and Kaneka ED COIL ∞10 ExtraSoft is useful for the treatment of high grade DAVF.

Background: Cerebral vasospasm (CVS) following subarachnoid hemorrhage occurs in up to 70% of patients. Recently, stents have been used to successfully treat CVS. This implies that the force required to expand spastic vessels and resolve vasospasm is lower than previously thought., Objective: We develop a mechanistic model of the spastic arterial wall to provide insight into CVS and predict the forces required to treat it., Material and Methods: The arterial wall is modelled as a cylindrical membrane using a constrained mixture theory that accounts for the mechanical roles of elastin, collagen and vascular smooth muscle cells (VSMC). We model the pressure diameter curve prior to CVS and predict how it changes following CVS. We propose a stretch-based damage criterion for VSMC and evaluate if several commercially available stents are able to resolve vasospasm., Results: The model predicts that dilatation of VSMCs beyond a threshold of mechanical failure is sufficient to resolve CVS without damage to the underlying extracellular matrix. Consistent with recent clinical observations, our model predicts that existing stents have the potential to provide sufficient outward force to successfully treat CVS and that success will be dependent on an appropriate match between stent and vessel., Conclusion: Mathematical models of CVS can provide insights into biological mechanisms and explore treatment approaches. Improved understanding of the underlying mechanistic processes governing CVS and its mechanical treatment may assist in the development of dedicated stents.

Background: Distal embolization or movement of the thrombus to previously uninvolved vasculature are feared complications during stroke thrombectomy. We looked at associated factors in a consecutive series of patients who underwent thrombectomy with the same endovascular device., Methods: We included all patients with acute ischemic stroke in the anterior or posterior circulation, who underwent thrombectomy with the same thrombectomy device for acute stroke from 2013 to 2016. Distal embolization was defined as any movement of the thrombus into a previously uninvolved portion of the cerebral vasculature or the presence of thrombotic material further downstream in the affected vessel, which occurred after the initial angiogram. We studied patient-related as well as technical factors to determine their association with distal emboli., Results: In this study 167 consecutive acute stroke patients treated with the emboTrap® device (Cerenovus, Irvine, CA, USA) were included with a median National Institutes of Health Stroke Scale (NIHSS) of 15 (range 2-30) and mean age of 67 years (SD 13.1 years). Of the patients in our cohort 20 (11.9%) experienced distal emboli, with 2.3% into a new territory and 9.6% into a territory distal to the primary occlusion. On univariate analysis, age, intravenous tissue plasminogen activator (tPA), posterior circulation occlusions, and general anesthesia were associated with distal emboli. On multivariate analysis, only posterior circulation occlusions (odds ratio OR 4.506 95% confidence interval CI 1.483-13.692, p = 0.008) were significantly associated with distal emboli. Distal embolization was not significantly associated with worse functional outcomes at 3 months, increased mortality or increased bleeding risk., Conclusion: Posterior circulation occlusions were significantly associated with distal emboli during thrombectomy, possibly due to the lack of flow arrest during such procedures. New techniques and devices should be developed to protect against embolic complications during posterior circulation stroke thrombectomy.

Thrombectomy is a technique that has completely changed the management of acute stroke and current devices have shown that they can achieve upwards of 90% successful recanalization in selected cohorts. However, despite the effectiveness of these devices, there are a proportion of patients who still fail to achieve reperfusion of the affected vascular territory and an even larger portion of patients who have poor functional outcomes in spite of successful recanalization. There are no guidelines on how to treat these patients when such failures occur. In an effort to understand the underpinnings of how failed thrombectomy occurs, we extensively reviewed the current literature in clot properties, vascular access problems, stroke pathogenic mechanisms, embolic complications, failed procedures and pre-procedural imaging. A short summary of each of these contentious areas are provided and the current state of the art. Together these elements give a cohesive overview of the mechanisms of failed thrombectomy as well as the controversies facing the field. New techniques and devices can then be developed to minimize such factors during stroke thrombectomy.

Background: The region of the brain supplied by the anterior choroidal artery (AChoA) is exquisitely eloquent. Aneurysms arising at or close to the origin of the vessel are not uncommon and damage or occlusion to the vessel can result in devastating consequences. The optimal treatment strategy is yet to be determined., Objective: We sought to determine the efficacy of flow diversion for the treatment of unruptured AChoA aneurysms., Method: A retrospective review of our prospectively maintained database was performed to identify all patients with unruptured aneurysms of the AChoA between March 2009 and May 2017. The fundus size, number and type of flow-diverting stent (FD), complications and follow-up data were recorded., Results: We identified 30 patients (60% female), average age 52.8 ± 10.8 years (range 27-73), with 30 aneurysms. The aneurysms were generally small with a mean fundus diameter of 3.4 mm (range 1-7 mm). Early angiographic follow-up data were available for all patients at which point 15 aneurysms were completely occluded (50%). Delayed angiographic follow-up was available in 24 patients and occlusion was seen in 21 patients (87.5%). Of the patients one developed transient ischemic symptoms after interruption of the antiplatelet medication and another patient had a small embolic infarct with transient symptoms in the periprocedural period., Conclusion: Flow diversion can be used to successfully treat aneurysms of the AChoA. The treatment carries a high rate of technical and radiological success with a good safety profile.

Background: Recently, numerous devices dedicated to the treatment of wide-necked aneurysms have become available. We present our initial experience with the pCANvas device and present the technical success rate, clinical outcome and immediate angiographic occlusion rates., Objective: We sought to determine the efficacy of flow with the pCANvas for the treatment of unruptured intracranial aneurysms., Methods: We performed a retrospective review of our prospectively collected data to identify patients treated with the pCANvas device between February 2015 and February 2017. The patient demographics, aneurysm characteristics, immediate and delayed clinical and radiographic follow-up data were recorded., Results: We identified 17 patients (13 female) treated only with the pCANvas device. The average age of the patients was 60.5 ± 13.3 years (range 25-75 years). The average dome width was 7.6 ± 3.2 mm (range 3-15.8 mm), dome height 7.1 ± 3.2 mm (range 3-12.9 mm) and neck width 5.4 ± 3.2 (range 3-16.3 mm). The average aspect ratio was 1.5 ± 0.8 (range 0.6-3.7). At the end of the procedure 15 aneurysms continued complete filling of the aneurysm (Raymond Roy Classification[RRC] 3) with 2 aneurysms showing only filling of the neck of the aneurysm (RRC 2). Early follow-up angiography was available for 16 patients and at this stage 11 aneurysms showed persistent and complete filling of the aneurysm (RRC 3), 5 aneurysms showed complete occlusion of the aneurysm (RRC 1) and 7 aneurysms underwent repeat treatment with coiling., Conclusion: The early results on the use of the pCANvas are promising; however, longer term follow-up and larger studies are required.

Dural arteriovenous fistulas (DAVF) involving the anterior and posterior condylar vein at the skull base are rare but important to recognize. Due to the highly variable anatomy of the venous system of the skull base, detailed anatomical knowledge is essential for correct diagnosis and appropriate treatment of these lesions. In this report we review the normal anatomy of the condylar veins and describe rare and, to our knowledge, not previously reported anatomical variants. We also highlight the treatment modalities for these lesions with focus on the endovascular transvenous occlusion based on four consecutive cases from our center.

Purpose: There is a controversy concerning the risk of rupture of small intracranial aneurysms. We sought to determine the size and morphological features of ruptured intracranial aneurysms., Material and Methods: The hospital files and images from all patients referred during one decade (2007-2016) to a specialized neurovascular center were retrospectively reviewed. Neck diameter, fundus depth and width as well as neck width based on catheter angiography were measured. Aneurysm morphology was classified as either regular, lobulated, irregular or fusiform., Results: A total of 694 consecutive patients with aneurysmal subarachnoid hemorrhage (aSAH) were identified (65.9% female, median age 54.3 years). The anterior communicating artery (AcomA) was the most frequent location of ruptured aneurysms. The medians for aneurysm depth, width and neck diameter were 5 mm, 4.5 mm and 3 mm, respectively. A regular contour of the aneurysm sac was found in 19%., Conclusion: The majority of aSAH are caused by small intracranial aneurysms. There is no safety margin in terms of small aneurysm size of regular shape without daughter aneurysms. Treatment should also be offered to patients with small, regularly shaped intracranial aneurysms, together with an empirical risk-benefit assessment.

Purpose: There is limited information available on the incidence of in-stent stenosis (ISS) secondary to the use of flow-diverting stents in the intracranial vasculature. We sought to determine the incidence, severity, and clinical course of ISS on angiographic follow-up after treatment of saccular aneurysms with p64., Methods: We retrospectively reviewed all patients who underwent treatment of a saccular (ruptured and unruptured) intracranial aneurysm with ≥1 p64 between 2011 and 2015. Fusiform aneurysms and dissections were excluded. Aneurysms with prior or concomitant saccular treatment (e. g., coiling, clipping) were included. Extradural targets and aneurysms with parent vessel implants other than p64 were excluded. ISS was assessed on follow-up angiography and defined as <50% (mild), 50-75% (moderate), or >75% (severe)., Results: In total, 205 patients (147 female, 71.7%; median age 57 years), with 223 saccular aneurysms were treated with p64 and had at least 9 months of digital subtraction angiography (DSA) follow-up completed. There was no DSA follow-up available in 8 patients. ISS of any degree at any time was recognized in 65/223 (29.1%) of all target aneurysms. The maximal degree of lumen loss was <50% in 40 lesions (17.9%), 50-75% in 19 lesions (8.5%), and >75% in 6 lesions (2.7%). ISS did not cause a focal neurological deficit in any patient. No progression from stenosis to occlusion was observed. Balloon angioplasty was performed in 1 lesion and was well tolerated. In 56 lesions (84.8%), a significant reduction of ISS occurred spontaneously, 2 mild stenoses remained stable, and for 6 lesions the long-term follow-up is pending., Conclusion: Treatment with p64 is associated with an overall rate of 8.5% moderate ISS (50-75%) and 2.7% severe ISS (>75%), which is comparable with the rate of ISS reported in the literature for other flow diverting stents. There is a tendency for ISS to spontaneously improve over time.

The recent success of endovascular stroke treatment has heralded a new era in the management of acute ischemic stroke (AIS) with significantly improved outcome for patients. A large number of patients may be amenable to this new treatment and as the evidence expands the number of patients eligible for mechanical thrombectomy continues to increase. Recent evidence suggests that the time window for treatment can be extended up to 24 h after symptom onset for patients with anterior circulation strokes; however, many clinicians and medical professionals may not be aware of these recent changes and it is important that they are kept up-to-date with this rapidly evolving treatment. This review provides an overview of the recent successful trials and highlights important steps that should be instituted in order to achieve rapid reperfusion and optimize the outcome for ischemic stroke patients. It also looks at the remaining controversies facing the field of thrombectomy. A short summary of each of these contentious areas is provided and the current state of the art.

Purpose: The optimal strategy for the treatment of M1 segment aneurysms has not yet been determined as both standard microneurosurgical and endovascular techniques can pose challenges. We sought to determine the efficacy of flow diverting stents to treat small, unruptured aneurysms of the M1 segment., Methods: We retrospectively reviewed our database of prospectively collected information for all patients treated with flow diversion for an unruptured saccular aneurysm of the middle cerebral artery (MCA) between February 2009 and February 2016. The relationship to early cortical branches, aneurysm fundus size, number and type of flow diverting stent (FDS), complications and follow-up data were recorded., Results: In total 15 patients were identified that matched our inclusion criteria (11 female and 4 male). The average age of the patients was 58.3 years (range 14-76 years). All patients had a single aneurysm affecting the M1 segment of the MCA, 10 (66.6%) of which were related to early cortical branches and 10 aneurysms were located on the left (66.6%). The average aneurysm fundus size was 3 mm (range 2-9 mm) and 13 patients had follow-up angiographic studies. In total, 8 aneurysms were completely excluded, and 6 remained incompletely occluded (3 modified Raymond-Roy classification [mRRC] II and 3 mRRC IIIa). One patient suffered a stroke and another patient had an iatrogenic vessel dissection that was not flow limiting., Conclusion: Flow diversion can be used to treat small, unruptured aneurysms of the M1 segment of the MCA and even though side vessel occlusion can occur clinically relevant infarction occurs infrequently.