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Background and Purpose: Flow diversion has gradually become a standard treatment for intracranial aneurysms of the anterior circulation. Recently, the off-label use of the flow diverters to treat posterior circulation aneurysms has also increased despite initial concerns of rupture and the suboptimal results. This study aimed to explore the change in complication rates and treatment outcomes across time for posterior circulation aneurysms treated using flow diversion and to further evaluate the mechanisms and variables that could potentially explain the change and outcomes., Materials and Methods: A retrospective review using a standardized data set at multiple international academic institutions was performed to identify patients with ruptured and unruptured posterior circulation aneurysms treated with flow diversion during a decade spanning January 2011 to January 2020. This period was then categorized into 4 intervals., Results: A total of 378 procedures were performed during the study period. Across time, there was an increasing tendency to treat more vertebral artery and fewer large vertebrobasilar aneurysms ( P = .05). Moreover, interventionalists have been increasingly using fewer overlapping flow diverters per aneurysm ( P = .07). There was a trend toward a decrease in the rate of thromboembolic complications from 15.8% in 2011-13 to 8.9% in 2018-19 ( P = .34)., Conclusions: This multicenter experience revealed a trend toward treating fewer basilar aneurysms, smaller aneurysms, and increased usage of a single flow diverter, leading to a decrease in the rate of thromboembolic and hemorrhagic complications., (© 2022 by American Journal of Neuroradiology.)

Objective: Mechanical endovascular thrombectomy (EVT) is an increasingly relied-on treatment for clot retrieval in the context of ischemic strokes, which otherwise are associated with significant morbidity and mortality. Despite several known risks associated with this procedure, there is a high degree of technical heterogeneity across both centers and operators. The most common procedural complications occur at the point of transfemoral access (the common femoral artery), and include access-site hematomas, dissections, and pseudoaneurysms. Other interventional fields have previously popularized the use of ultrasound to enhance the anatomical localization of structures relevant to vascular access and thereby reducing access-site complications. In this study, the authors aimed to describe the ultrasound-guided EVT technique performed at a large, quaternary neurovascular referral center, and to characterize the effects of ultrasound guidance on access-site complications., Methods: A retrospective chart review of all patients treated with EVT at a single center between January 2013 and August 2020 was performed. Patients in this cohort were treated using a universal, unique, ultrasound-guided, single-wall puncture technique, which bears several theoretical advantages over the standard technique of arterial puncture via palpation., Results: There were 479 patients treated with EVT within the study period. Twenty patients in the cohort were identified as having experienced some form of access-site complication. Eight (1.67%) of these patients experienced minor access-site complications, all of which were groin hematomas and none of which were clinically significant, as defined by requiring surgical or interventional management or transfusion. The remaining 12 patients experienced arterial dissection (n = 5), arterial pseudoaneurysm (n = 4), retroperitoneal hematoma (n = 2), or arterial occlusion (n = 1), with only 1.04% (5/479) requiring surgical or interventional management or transfusion., Conclusions: The authors found an overall reduction in total access-site complications as well as minor access-site complications in the study cohort compared with previously published randomized controlled trials and observational studies in the recent literature. The findings suggested that there may be a role for routine use of ultrasound-guided puncture techniques in EVT to decrease rates of complications.

Background: Research on the presence of sex-based differences in the outcomes of patients undergoing endovascular thrombectomy for acute ischemic stroke has reached differing conclusions., Purpose: This review aimed to determine whether sex influences the outcome of patients with large-vessel occlusion stroke undergoing endovascular thrombectomy., Study Selection: We performed a systematic review and meta-analysis of endovascular thrombectomy studies with either stratified cohort outcomes according to sex (females versus males) or effect size reported for the consequence of sex versus outcomes. We included 33 articles with 7335 patients., Data Analysis: We pooled ORs for the 90-day mRS score, 90-day mortality, symptomatic intracranial hemorrhage, and recanalization., Data Synthesis: Pooled 90-day good outcomes (mRS ≤ 2) were better for men than women (OR = 1.29; 95% CI, 1.09-1.53; P = <.001, I 2 = 56.95%). The odds of the other outcomes, recanalization (OR = 0.94; 95% CI, 0.77-1.15; P = .38, I 2 = 0%), 90-day mortality (OR = 1.11; 95% CI, 0.89-1.38; P = .093, I 2 = 0%), and symptomatic intracranial hemorrhage (OR = 1.40; 95% CI, 0.99-1.99; P = .069, I 2 = 0%) were comparable between men and women., Limitations: Moderate heterogeneity was found. Most studies included were retrospective in nature. In addition, the randomized trials included were not specifically designed to compare outcomes between sexes., Conclusions: Women undergoing endovascular thrombectomy for large-vessel occlusion have inferior 90-day clinical outcomes. Sex-specific outcomes should be investigated further in future trials as well as pathophysiologic studies., (© 2021 by American Journal of Neuroradiology.)

Background and Purpose: Imaging of the cerebral venous sinuses has evolved Substantially during the past 2 decades, and most recently intravascular sinus imaging with sonography has shed light on the pathophysiology of sinus thrombosis and intracranial hypertension. Optical coherence tomography is the highest resolution intravascular imaging technique available but has not been previously used in cerebral sinus imaging. The purpose of this study was to develop a preclinical animal model of endovascular optical coherence tomography cerebral venous sinus imaging and compare optical coherence tomography findings with histology., Materials and Methods: Four consecutive Yorkshire swine were selected. The superior sagittal sinus was first catheterized with a microwire, and the optical coherence tomography catheter was delivered via a monorail technique into the sinus. Luminal blood was cleared with a single arterial injection. After structural and Doppler optical coherence tomography imaging, a craniotomy was performed and the sinus and adjacent dura/veins were resected. Bland-Altman analysis was performed to compare optical coherence tomography and histology., Results: Technically successful optical coherence tomography images were obtained in 3 of 4 swine. The luminal environment and visualization of dural arteries and draining cortical veins were characterized. The average maximum diameters of the sinus, dural arteries, and cortical veins were 3.14 mm, 135 µm, and 260 µm, respectively. Bland-Altman analysis demonstrated good agreement between histology and optical coherence tomography images., Conclusions: Endovascular optical coherence tomography imaging was feasible in this preclinical animal study. Adoption of this imaging technique in the human cerebral venous sinus could aid in the diagnosis, treatment, and understanding of the pathophysiology of various diseases of the sinus. Human safety and feasibility studies are needed., (© 2020 by American Journal of Neuroradiology.)

Background: The Pipeline Embolization Device (PED; Medtronic) has been used off-label for the treatment of challenging posterior circulation aneurysms. Data on this modality are primarily limited to small retrospective single-center series., Objective: To assess safety and efficacy of this treatment by establishing an international, multicenter collaboration., Methods: Consecutive posterior circulation aneurysms treated with the PED from 2012 to 2019 across 11 neurovascular centers were retrospectively reviewed. Baseline demographics, aneurysm and treatment characteristics, complications, occlusion status, and functional outcome were assessed., Results: There were 149 posterior circulation aneurysms treated with PED in 146 patients. A total of 24 (16.4%) patients presented with subarachnoid hemorrhage. Most aneurysms were dissecting/blister (36.2%) in morphology, followed by saccular (35.6%) and fusiform (28.2%). The most common locations were the vertebral (51.7%) and basilar arteries (22.8%). Complete or near-complete occlusion (>90%) was achieved in 90.9% of aneurysms at a median follow-up of 12 mo. Dissecting/blister aneurysms were most likely to occlude (P = .06). Symptomatic neurologic complications occurred in 9.4% of aneurysms, associated with larger size, ruptured presentation, presentations with brain stem compression, cranial nerve palsy, or stroke. Favorable functional outcome (modified Rankin Score 0-2) was achieved in 86.2% of patients. There were 6 fatalities of which 4 occurred in aneurysmal subarachnoid hemorrhage patients., Conclusion: This multicenter study shows that PED for the treatment of posterior circulation is preferentially used for the treatment of fusiform and dissecting/blister aneurysm morphologies. Despite the challenges presented by these less-common morphologies, flow diversion may be performed with a neurologic complication rate of about 10% and favorable long-term aneurysm occlusion rates., (Copyright © 2020 by the Congress of Neurological Surgeons.)

Background: Hemorrhagic vascular lesions in the posterior cerebral circulation such as ruptured aneurysms and dissections can be challenging to treat. Flow diversion has become an important off-label option, but few studies have analyzed the safety of these devices in this setting. Using an international, multicenter cohort, we reviewed posterior circulation subarachnoid hemorrhage (SAH) patients treated with the Pipeline Embolization Device (PED) in the acute setting and assessed the incidence of Takotsubo cardiomyopathy (TCM)., Methods: Eleven neurovascular centers were queried to identify cases of posterior circulation aneurysms or dissections treated with the PED in the acute setting of SAH. Among those, 5 centers had cases that matched the inclusion criteria. The following variables were evaluated: demographics, the location and morphology of the aneurysm, the clinical presentation, the specific form of treatment, complications including the development of TCM, antiplatelet medication regimen, and follow-up time., Results: A total of 23 patients were treated with PED after posterior circulation SAH, and 13% of these developed TCM. The lesions were the result of hemorrhagic intracranial dissection (8 patients), ruptured pseudoaneurysm (3), ruptured saccular aneurysm (7), blister aneurysm (4), and fusiform aneurysm (1). Ninety-one percent of patients had complete or near-complete aneurysm occlusion on follow-up imaging. Five patients died in the perioperative period; 16/18 survivors had a favorable outcome., Conclusions: We describe an unexpectedly high incidence of TCM after the placement of PEDs in patients with posterior circulation SAH in our large case series. Further studies will be needed to elucidate possible causes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background and Purpose: Large prospective observational studies have cast doubt on the common assumption that endovascular thrombectomy (EVT) is superior to intravenous thrombolysis for patients with acute basilar artery occlusion (BAO). The purpose of this study was to retrospectively review our experience for patients with BAO undergoing EVT with modern endovascular devices., Methods: All consecutive patients undergoing EVT with either a second-generation stent retriever or direct aspiration thrombectomy for BAO at our regional stroke center from January 1, 2013 to March 1, 2019 were included. The primary outcome measure was functional outcome at 1 month using the modified Rankin Scale (mRS) score. Multivariable logistic regression was used to assess the association between patient characteristics and dichotomized mRS., Results: A total of 43 consecutive patients underwent EVT for BAO. The average age was 67 years with 61% male patients. Overall, 37% (16/43) of patients achieved good functional outcome. Successful reperfusion was achieved in 72% (31/43) of cases. The median (interquartile range) stroke onset to treatment time was 420 (270-639) minutes (7 hours) for all patients. The procedure-related complication rate was 9% (4/43). On multivariate analysis, posterior circulation Alberta stroke program early computed tomography score and Basilar Artery on Computed Tomography Angiography score were associated with improved functional outcome., Conclusion: EVT appears to be safe and feasible in patients with BAO. Our finding that time to treatment and successful reperfusion were not associated with improved outcome is likely due to including patients with established infarcts. Given the variability of collaterals in the posterior circulation, the paradigm of utilizing a tissue window may assist in patient selection for EVT. Magnetic resonance imaging may be a reasonable option to determine the extent of ischemia in certain situations.

Objective: Although studies have shown that some degree of iatrogenic endothelial injury occurs during endovascular thrombectomy (EVT), the clinical significance of such injury is uncertain. Furthermore, it is likely that iatrogenic effects such as endothelial denudation, intimal dissection, and tunica media edema will have varying clinical implications. The purpose of this study was to assess the feasibility of endovascular optical coherence tomography (OCT) in quantifying vessel injury in real time after EVT, correlate vessel injury with histological findings, and perform imaging at varying time intervals after EVT to assess the impact of prolonged direct exposure of the vessel to the thrombus., Methods: Yorkshire swine weighing 35-40 kg were selected for use as the animal model, with a total of 9 vessels from 3 swine examined. Thrombectomy was performed using a second-generation stent retriever 1, 3, and 6 hours after thrombus deposition. The presence and degree of denudation of the endothelium, detachment and separation of the layers of the tunic media, hemorrhage within the media, dissection of the vessels, and thrombus within the lumina were assessed using OCT images acquired immediately after EVT. Bland-Altman analysis indicated that these OCT findings were correlated with postmortem histological findings., Results: OCT image acquisition was technically successful in all cases. Endothelial denudation was present in 65% ± 16%, 87% ± 8%, and 93% ± 7% of the vessel surface 1, 3, and 6 hours, respectively, after thrombus deposition and subsequent EVT. Residual intraluminal thrombus was present in vessels at all time intervals despite complete angiographic revascularization. Bland-Altman plots showed good agreement between OCT and histological analysis with respect to the degree of endothelial denudation and elevation, separation of the tunica media, and hemorrhage within the media. OCT appears to be more specific than histological analysis in detecting endothelial elevation., Conclusions: OCT is a feasible method that can be used to assess vascular injury after EVT with histological accuracy. Varying degrees of vessel injury occur after EVT, and residual luminal thrombus can be present despite complete angiographic revascularization.

Flow modification has caused a paradigm shift in the management of intracranial aneurysms. Since the FDA approval of the Pipeline Embolization Device (Medtronic, Dublin, Ireland) in 2011, it has grown to become the modality of choice for a range of carefully selected lesions, previously not amenable to conventional endovascular techniques. While the vast majority of flow-diverting stents operate from within the parent artery (ie, endoluminal stents), providing a scaffold for endothelial cells growth at the aneurysmal neck while inducing intra-aneurysmal thrombosis, a smaller subset of endosaccular flow disruptors act from within the lesions themselves. To date, these devices have been used mostly in Europe, while only utilized on a trial basis in North America. To the best of our knowledge, there has been no dedicated review of these devices. We therefore sought to present a comprehensive review of currently available endosaccular flow disruptors along with high-resolution schematics, presented with up-to-date available literature discussing their technical indications, procedural safety, and reported outcomes., (© Congress of Neurological Surgeons 2019.)

Cerebral endovascular neurosurgery has transformed the way we manage cerebrovascular disease. Several landmark trials have demonstrated the effectiveness of endovascular techniques leading to continued technological development and applications for various diseases. The utilization of optical technologies and devices is already underway in the field of endovascular neurosurgery. We discuss the contemporary paradigms, challenges, and current optical applications for the most common cerebrovascular diseases: carotid atherosclerotic disease, cerebral aneurysms, intracranial atherosclerosis, and dural arteriovenous fistulas. We also describe needs-based opportunities for future optical applications, with the goal of providing researchers a sense of where we feel optical technologies could impact the way we manage cerebral disease.

Background: The metrics of imaging-to-puncture and imaging-to-reperfusion were recently found to be associated with the clinical outcomes of endovascular thrombectomy for acute ischemic stroke. However, measures for improving workflow within hospitals to achieve better timing results are largely unexplored for endovascular therapy. The aim of this study was to examine our experience with a novel smartphone application developed in house to improve our timing metrics for endovascular treatment., Methods: We developed an encrypted smartphone application connecting all stroke team members to expedite conversations and to provide synchronized real-time updates on the time window from stroke onset to imaging and to puncture. The effects of the application on the timing of endovascular therapy were evaluated with a secondary analysis of our single-center cohort. Our primary outcome was imaging-to-puncture time. We assessed the outcomes with nonparametric tests of statistical significance., Results: Forty-five patients met our criteria for analysis among 66 consecutive patients with acute ischemic stroke who received endovascular therapy at our institution. After the implementation of the smartphone application, imaging-to-puncture time was significantly reduced (preapplication median time, 127 minutes; postapplication time, 69 minutes; P < 0.001). Puncture-to-reperfusion time was not affected by the application use (42 minutes vs. 36 minutes)., Conclusion: The use of smartphone applications may reduce treatment times for endovascular therapy in acute ischemic stroke. Further studies are needed to confirm our findings., (Copyright © 2017. Published by Elsevier Inc.)

Background: Endovascular thrombectomy is an effective procedure to treat selected ischemic strokes, as shown in recent randomized controlled trials (RCTs). The generalizability of these trial data to real-world settings, however, is unknown. The aim of this study was to examine our single-center experience with endovascular thrombectomy for acute ischemic strokes and perform a comparative outcome analysis to the most recent RCTs., Methods: We performed a 5-year retrospective analysis, from April 2011 to March 2016, on 66 consecutive patients with acute ischemic stroke who received endovascular thrombectomy at our institution. The Alberta Stroke Program Early CT Score (ASPECTS) and the National Institutes of Health Stroke Scale were used to assess preoperative status. Our primary outcomes were the modified Rankin Score (mRS) at 90 days and recanalization grade measured by the 6-point thrombolysis in cerebral infarction (TICI) grading system., Results: Sixty-six patients received endovascular treatment during the study period. Among the patients examined, 35 (53%) had a favorable outcome (mRS 0-2 at 90 days), 23 (35%) a poor outcome (mRS 3-5), and 8 (12%) died. Successful recanalization (TICI score 3-5) was achieved in 68% of cases. In univariate analysis, patients with good outcome at 90 days had significantly greater ASPECTS, lower National Institutes of Health Stroke Scale, and higher TICI scores. In a multiple logistic regression model, higher ASPECTS and TICI scores were significantly and independently associated with favorable outcome., Conclusions: Excellent outcomes, as demonstrated by the recent RCTs, can be achieved in clinical practice and reproduced in dedicated tertiary centers., (Copyright © 2016 Elsevier Inc. All rights reserved.)