First-in-human, robotic-assisted neuroendovascular intervention

Robotic-assisted technology has been used as a tool to enhance open and minimally invasive surgeries as well as percutaneous coronary and peripheral vascular interventions. It offers many potential benefits, including increased procedural and technical accuracy as well as reduced radiation dose during fluoroscopic procedures. It also offers the potential for truly “remote” procedures. Despite these benefits, robotic technology has not yet been used in the neuroendovascular field, aside from diagnostic cerebral angiography. Here, we report the first robotic-assisted, therapeutic, neuroendovascular intervention performed in a human. This was a stent-assisted coiling procedure to treat a large basilar aneurysm. All intracranial steps, including stent placement and coil deployment, were performed with assistance from the CorPath^© GRX Robotic System (Corindus, a Siemens Healthineers Company, Waltham, MA, USA). This represents a major milestone in the treatment of neurovascular disease and opens the doors for the development of remote robotic neuroendovascular procedures.

Association of Time From Stroke Onset to Groin Puncture With Quality of Reperfusion After Mechanical Thrombectomy: A Meta-analysis of Individual Patient Data From 7 Randomized Clinical Trials

Importance

Reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke (AIS) treated with endovascular thrombectomy (EVT) for large-vessel intracranial occlusion. However, data are scarce on the association between the time from onset and reperfusion results.

Objective

To analyze the rate of reperfusion after EVT started at different intervals after symptom onset in patients with AIS.

Design, Setting, and Participants

We conducted a meta-analysis of individual patient data from 7 randomized trials of the Highly Effective Reperfusion Using Multiple Endovascular Devices (HERMES) group. This is a multicenter cohort study of the intervention arm of randomized clinical trials included in the HERMES group. Patients with anterior circulation AIS who underwent EVT for M1/M2 or intracranial carotid artery occlusion were included. Each trial enrolled patients according to its specific inclusion and exclusion criteria. Data on patients eligible but not enrolled (eg, refusals or exclusions) were not available. All analyses were performed by the HERMES biostatistical core laboratory using the pooled database. Data were analyzed between December 2010 and April 2015.

Main Outcomes and Measures

Successful reperfusion was defined as a modified thrombolysis in cerebral infarction score of 2b/3 at the end of the EVT procedure adjusted for age, occlusion location, pretreatment intravenous thrombolysis, and clot burden score and was analyzed in relation to different intervals (onset, emergency department arrival, imaging, and puncture) using mixed-methods logistic regression.

Results

Among the 728 included patients, with a mean (SD) age of 65.4 (13.5) years and of whom 345 were female (47.4%), decreases in rates of successful reperfusion defined as a thrombolysis in cerebral infarction score of 2b/3 were observed with increasing time from admission or first imaging to groin puncture. The magnitude of effect was a 22% relative reduction (odds ratio, 0.78; 95% CI, 0.64-0.95) per additional hour between admission and puncture and a 26% relative reduction (odds ratio, 0.74; 95% CI, 0.59-0.93) per additional hour between imaging and puncture.

Conclusions and Relevance

Because the probability of reperfusion declined significantly with time between hospital arrival and groin puncture, we provide additional arguments for minimizing the intervals after symptom onset in anterior circulation acute ischemic stroke.

First clinical experience with the new Surpass Evolve flow diverter: technical and clinical considerations

Objective

To describe the results in patients treated with the Surpass Evolve (SE) device, the new generation of Surpass flow diverters.

Methods

Twenty-five consecutive patients (20 women, average age 58 years), with anterior or posterior circulation aneurysms treated with SEs in two early-user centers, were included. Device properties and related technical properties, imaging and clinical follow-up data, and intraprocedural, early (<30 days) and delayed (>30 days) neurological complications, further divided into minor (silent/non-permanent) and major (permanent) complications, were recorded and analyzed.

Results

Twenty-nine SEs were successfully implanted in all subjects to treat 26 aneurysms using an 0.027" microcatheter with an average of 1.2 stents per patient. No intraprocedural thromboembolic or hemorrhagic complications were seen. At clinical follow-up, 24/25 (96%) patients had a modified Rankin Score of 0–2. Mortality was 0%. Imaging follow-up, available in 22/25 (88%) patients (median follow-up time 4 months), showed a complete aneurysm occlusion in 13/23 (57%) imaged lesions. Minor, transitory neurological deficits were recorded in 5/25 (20%) patients. One (4%) major complication was seen in one patient (4%) with a left-sided hemispheric stroke on postprocedural day 4 due to an acute stent thrombosis.

Conclusions

Preliminary experience in patients demonstrates a good performance of the SE. This newly designed implant maintains the engineering characteristics of Surpass flow diverters, including precise placement due to its lower foreshortening and a high mesh density, yet can be deployed through a significantly lower-profile delivery system.

Per-region interobserver agreement of Alberta Stroke Program Early CT Scores (ASPECTS)

Background and purpose

The Alberta Stroke Program Early CT Score (ASPECTS) is a commonly used scoring system to select patients with stroke for endovascular treatment (EVT). However, the inter- and intra-reader variability is high.

Objective

To determine whether the inter- and intra-reader variability is different for various regions of the ASPECTS scoring system by evaluating the interobserver variability of ASPECTS between different readers in a per-region analysis.

Materials and methods

All patients with acute ischemic stroke who proceeded to EVT in our institutions over a 4-year period were retrospectively identified from a prospectively maintained database. Images were reviewed by two experienced neuroradiologists, who recalculated the ASPECTS independently. We examined each region of the ASPECTS system to evaluate agreement between the raters in each area.

Results

375 patients were included. The median total ASPECTS was 9 (IQR 8–9). The most common region showing ischemic change was the insula, with the M6 region being least commonly affected. Overall interobserver agreement for ASPECTS using Cohen’s κ was 0.56 (95% CI 0.51 to 0.61). The region with the highest agreement was the insula (κ=0.56; 0.48 to 0.64). The region with the lowest agreement was M3 (κ=0.34; 0.12 to 0.56). Agreement was relatively good when ASPECTS were dichotomized into 0–5 versus 6–10 (κ=0.66; 0.49 to 0.84).

Conclusions

Substantial interobserver variability is found when calculating ASPECTS. This variability is region dependent, and practitioners should take this into account when using ASPECTS for treatment decisions in patients with acute stroke.

Abstract 141: Artificial Intelligence to Improve the Detection and Triage of Cerebral Aneurysms

Cerebral Aneurysms (CAs) may occur in 5-10% of the population. They can be often missed because they require a very methodological diagnostic approach. We developed an algorithm using artificial intelligence to assist and supervise and detect CAs.

Methods: We developed an automated algorithm to detect CAs. The algorithm is based on 3D convolutional neural network modeled as a U-net. We included all saccular CAs from 2014 to 2016 from a single center. Normal and pathological datasets were prepared and annotated in 3D using an in-house developed platform. To assess the accuracy and to optimize the model, we assessed preliminary results using a validation dataset. After the algorithm was trained, a dataset was used to evaluate final IA detection and aneurysm measurements. The accuracy of the algorithm was derived using ROC curves and Pearson correlation tests.

Results: We used 528 CTAs with 674 aneurysms at the following locations: ACA (3%), ACA/ACOM (26.1%), ICA/MCA (26.3%), MCA (29.4%), PCA/PCOM (2.3%), Basilar (6.6%), Vertebral (2.3%) and other (3.7%). Training datasets consisted of 189 CA scans. We plotted ROC curves and achieved an AUC of 0.85 for unruptured and 0.88 for ruptured CAs. We improved the model performance by increasing the training dataset employing various methods of data augmentation to leverage the data to its fullest. The final model tested was performed in 528 CTAs using 5-fold cross-validation and an additional set of 2400 normal CTAs. There was a significant improvement compared to the initial assessment, with an AUC of 0.93 for unruptured and 0.94 for ruptured. The algorithm detected larger aneurysms more accurately, reaching an AUC of 0.97 and a 91.5% specificity at 90% sensitivity for aneurysms larger than 7mm. Also, the algorithm accurately detected CAs in the following locations: basilar(AUC of 0.97) and MCA/ACOM (AUC of 0.94). The volume measurement (mm3) by the model compared to the annotated one achieved a Pearson correlation of 99.36.

Conclusion: The Viz.ai aneurysm algorithm was able to detect and measure ruptured and unruptured CAs in consecutive CTAs. The model has demonstrated that a deep learning AI algorithm can achieve clinically useful levels of accuracy for clinical decision support.

Artery of Davidoff and Schechter Supply in Dural Arteriovenous Fistulas

The artery of Davidoff and Schechter is a dural branch of the posterior cerebral artery that can supply the meninges close to the falcotentorial junction. It is usually not identified on angiography except when enlarged in the setting of a dural AVF or meningioma. The impact on treatment of the artery of Davidoff and Schechter supply to a fistula is not well-described in the literature. Our retrospective analysis of patients with dural AVFs treated at the Toronto Western Hospital between 2006 and 2018 identified 6 patients with dural AVFs receiving supply from artery of Davidoff and Schechter (of a total of 173 patients with dural AVFs). All patients were initially treated by transarterial embolization using liquid embolic agents. Three patients required a second endovascular procedure partly due to residual supply from artery of Davidoff and Schechter, and in all cases, angiographic cure was obtained. The treatment approach, challenges encountered, and potential complications of treating such fistulas are described.

Cerebrofacial venous metameric syndrome-spectrum of imaging findings

Cerebrofacial venous metameric syndrome (CVMS) is a complex craniofacial vascular malformation disorder in which patients have a constellation of venous vascular malformations affecting soft tissues, bone, dura, and neural structures including the eye and brain. It is hypothesized that a somatic mutation responsible for the venous abnormalities occurred prior to migration of the neural crest cells, and because of this, facial, osseous, and cerebral involvement typically follows a segmental or "metameric" distribution. The most commonly recognized form of CVMS is Sturge-Weber syndrome. However, a wide spectrum of CVMS phenotypical presentations exist with various metameric distributions of slow-flow vascular lesions including facial venous vascular malformations, developmental venous anomalies, venous angiomas, cavernous malformations (cavernomas), dural sinus malformations, and maybe even vascular tumors such as cavernous hemangiomas. Awareness of the various manifestations as described herewith is important for treatment and screening purposes.

Intracranial Dural Arteriovenous Fistulas with Pial Arterial Supply

BACKGROUND

Pial arterial supplies are sometimes found in patients with dural arteriovenous fistulas (DAVFs), though their characteristics have rarely been clarified.

OBJECTIVE

To investigate the characteristics of pial arterial supplies in DAVFs and to discuss their pathophysiology and treatment.

METHODS

Two hundred four consecutive patients with intracranial DAVFs over 11 yr were retrospectively reviewed. Clinical factors and radiological findings, including the presence of pial arterial supplies, were evaluated. Supply from a pial artery was classified into 2 categories: dilated pre-existing dural branches of pial arteries, and a "pure" pial supply.

RESULTS

Twenty-three of 204 patients (11.3%) showed an additional pial arterial supply. Multivariate analysis identified 3 independent predictors of a pial arterial supply: younger age (P < .0005), DAVF within the tentorium (P = .0162), and presence of venous dilatation (P = .0001). A dilated pre-existing dural branch of a pial artery was identified in 17 patients, while 8 had a pure pial supply. Of these 23 patients, 17 underwent interventional therapy. No postoperative intracranial hemorrhage or infarction occurred in patients with pial arterial supplies.

CONCLUSION

An additional pial supply is not uncommon in DAVFs and may be explained by a rich physiological pial arterial supply to the dura mater from the posterior circulation, while potential angiogenesis due to venous hypertension remains speculative. Prior to interventional treatment for DAVFs, recognition of a pial arterial supply to the DAVF might influence the treatment strategy and could help avoid inadvertent retrograde embolization of brain supplying vessels through the pial network.

Common Data Elements for Radiological Imaging of Patients with Subarachnoid Hemorrhage: Proposal of a Multidisciplinary Research Group

INTRODUCTION

Lack of homogeneous definitions for imaging data and consensus on their relevance in the setting of subarachnoid hemorrhage and unruptured intracranial aneurysms lead to a difficulty of data pooling and lack of robust data. The aim of the National Institute of Health/National Institute of Neurological Disorders and Stroke, Unruptured Intracranial Aneurysm (UIA) and Subarachnoid Hemorrhage (SAH) Common Data Elements (CDE) Project was to standardize data elements to ultimately facilitate data pooling and establish a more robust data quality in future neurovascular research on UIA and SAH.

METHODS

For the subcommittee 'Radiological imaging of SAH,' international cerebrovascular specialists with imaging expertise in the setting of SAH were selected by the steering committee. CDEs were developed after reviewing the literature on neuroradiology and already existing CDEs for other neurological diseases. For prioritization, the CDEs were classified into 'Core,' 'Supplemental-Highly Recommended,' 'Supplemental' and 'Exploratory.'

RESULTS

The subcommittee compiled 136 CDEs, 100 out of which were derived from previously established CDEs on ischemic stroke and 36 were newly created. The CDEs were assigned to four main categories (several CDEs were assigned to more than one category): 'Parenchymal imaging' with 42 CDEs, 'Angiography' with 49 CDEs, 'Perfusion imaging' with 20 CDEs, and 'Transcranial doppler' with 55 CDEs. The CDEs were classified into core, supplemental highly recommended, supplemental and exploratory elements. The core CDEs were imaging modality, imaging modality type, imaging modality vessel, angiography type, vessel angiography arterial anatomic site and imaging vessel angiography arterial result.

CONCLUSIONS

The CDEs were established based on the current literature and consensus across cerebrovascular specialists. The use of these CDEs will facilitate standardization and aggregation of imaging data in the setting of SAH. However, the CDEs may require reevaluation and periodic adjustment based on current research and improved imaging quality and novel modalities.

Acute Cortical Lesions in MELAS Syndrome: Anatomic Distribution, Symmetry, and Evolution

BACKGROUND AND PURPOSE

Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome is a rare mitochondrial disorder affecting children and young adults. Stroke-like episodes are often associated with acute cortical lesions in the posterior cerebral cortex and are classically described as asymmetric and transient. In this study we assessed the anatomic distribution of acute cortical lesions, the incidence of symmetry, and the temporal evolution of lesions.

MATERIALS AND METHODS

This was a retrospective cohort study of patients who had a confirmed genetic diagnosis of a pathogenic variant associated with MELAS and MR imaging performed at our center (2006-2018). Each MR imaging study was assessed for new lesions using T1, T2, FLAIR, DWI, ADC, and SWI. The anatomic location, symmetry, and temporal evolution of lesions were analyzed.

RESULTS

Eight patients with the same pathogenic variant of MELAS (MT-TL1 m.3243A>G) with 31 MR imaging studies were included. Forty-one new lesions were identified in 17 of the studies (5 deep, 36 cortical). Cortical lesions most commonly affected the primary visual cortex, the middle-third of the primary somatosensory cortex, and the primary auditory cortex. Thirty of 36 cortical lesions had acute cortical diffusion restriction, of which 21 developed cortical laminar necrosis on subacute imaging. Six of 11 studies with multiple lesions showed symmetric cortical involvement.

CONCLUSIONS

Acute cortical lesions in MELAS most commonly affect the primary visual, somatosensory, and auditory cortices, all regions of high neuronal density and metabolic demand. The most common pattern of temporal evolution is acute cortical diffusion restriction with subacute cortical laminar necrosis and chronic volume loss. Symmetric involvement is more common than previously described.

Decreased Subcortical T2 FLAIR Signal Associated with Seizures

Abnormally decreased T2/T2 FLAIR signal can be seen on brain imaging of patients who are experiencing clinical or subclinical seizures and can be associated with various intracranial pathologies. We identified 29 such patients. The abnormal signal was unilateral in 75.9% of patients. It affected various lobes of the brain, but only in the anterior circulation. In 28 patients (96.6%), there was corresponding decreased signal on DWI. The ADC was normal in all cases. In 26 patients (89.7%), there was corresponding low signal on SWI/gradient recalled-echo; 44.8% of patients underwent contrast-enhanced scans, and there was no abnormal enhancement. Twenty-two (75.9%) patients had documented clinical seizures on the day of imaging. The most frequent concomitant pathology was a subdural hematoma. Electroencephalograms obtained within 24 hours of imaging were available in 65.5%. Findings of all of these electroencephalograms were abnormal, and these electroencephalogram changes were either localized to the area of the abnormal MR imaging signal (where the signal was unilateral) or were bilateral (where the MR imaging changes were bilateral). In summary, decreased white matter T2/T2 FLAIR signal changes can be seen in patients with remarkably similar clinical findings (particularly seizures). These changes are often correlated with abnormal electroencephalogram activity localized to the involved lobes.

Quantitative color-coded digital subtraction neuroangiography for pediatric arteriovenous shunting lesions

BACKGROUND

Several complex pediatric neurovascular conditions are amenable to endovascular treatment. Given the unique anatomical and physiological challenges in children, there is an ongoing need for tools and techniques that provide accurate information for treatment planning, while minimizing exposure to ionizing radiation and contrast. This is more so for neonates and infants with high-flow arteriovenous (AV) shunts that are challenging to assess using conventional techniques.

OBJECTIVE

In this brief report, we describe, through representative cases, the potential role of quantitative color-coded digital subtraction angiography (qDSA) in neuroendovascular procedures in children with high-flow AV shunting lesions.

METHODS

Images were obtained using an ArtisQ biplane system (Siemens Healthineers, Erlangen, Germany). Post-processing was performed at a dedicated workstation (Syngo, Siemens) using the iFlow module to generate color-coded maps of individual digital subtraction angiography runs.

CONCLUSION

Color-coded qDSA provides real-time quantitative information in high-flow AV shunting neurovascular lesions. This can potentially help direct treatment choices, optimize endovascular treatment protocols, monitor outcomes, and determine treatment end points.

4D-CT angiography versus 3D-rotational angiography as the imaging modality for computational fluid dynamics of cerebral aneurysms

Background and purpose

Computational fluid dynamics (CFD) can provide valuable information regarding intracranial hemodynamics. Patient-specific models can be segmented from various imaging modalities, which may influence the geometric output and thus hemodynamic results. This study aims to compare CFD results from aneurysm models segmented from three-dimensional rotational angiography (3D-RA) versus novel four-dimensional CT angiography (4D-CTA).

Methods

Fourteen patients with 16 cerebral aneurysms underwent novel 4D-CTA followed by 3D-RA. Endoluminal geometries were segmented from each modality using an identical workflow, blinded to the other modality, to produce 28 'original' models. Each was then minimally edited a second time to match length of branches, producing 28 additional 'matched' models. CFD simulations were performed using estimated flow rates for 'original' models (representing real-world experience) and patient-specific flow rates from 4D-CTA for 'matched' models (to control for influence of modality alone).

Results

Overall, geometric and hemodynamic results were consistent between models segmented from 3D-RA and 4D-CTA, with correlations improving after matching to control for operator-introduced variability. Despite smaller 4D-CTA parent artery diameters (3.49±0.97 mm vs 3.78±0.92 mm for 3D-RA; p=0.005) and sac volumes (157 (37–750 mm3) vs 173 (53–770 mm3) for 3D-RA; p=0.0002), sac averages of time-averaged wall shear stress (TAWSS), oscillatory shear (OSI), and high frequency fluctuations (measured by spectral power index, SPI) were well correlated between 3D-RA and 4D-CTA 'matched' control models (TAWSS, R2=0.91; OSI, R2=0.79; SPI, R2=0.90).

Conclusions

Our study shows that CFD performed using 4D-CTA models produces reliable geometric and hemodynamic information in the intracranial circulation. 4D-CTA may be considered as a follow-up imaging tool for hemodynamic assessment of cerebral aneurysms.

A theory for polymicrogyria and brain arteriovenous malformations in HHT

Hereditary hemorrhagic telangiectasia (HHT) is generally considered a disorder of endothelial dysfunction, characterized by the development of multiple systemic arteriovenous malformations (AVMs), including within the brain. However, there have recently been a number of reports correlating HHT with malformations of cortical development, of which polymicrogyria is the most common type. Here we present 7 new cases demonstrating polymicrogyria in HHT, 6 of which demonstrate a brain AVM (bAVM) in close spatial proximity, with the aim of providing a common origin for the association. Upon reviewing patient genetics and imaging data and comparing with previously reported findings, we form 2 new conclusions: (1) polymicrogyria in HHT appears exclusively associated with a subset of mutations in the transmembrane protein endoglin that is involved with blood flow-related mechanotransduction signaling during angiogenesis and (2) the polymicrogyria is characteristically unilateral, typically focal, and correlates with vascular regions experiencing low fluid shear stress during corticogenesis in utero. Integrating these with findings in the literature from genetics and molecular biology experiments, we propose a theory suggesting haploinsufficient endoglin mutations, especially those that are dominant-negative, may predispose focal, aberrant hypersprouting angiogenesis during corticogenesis that leads to the production of polymicrogyria. This hypoxic insult may further serve as the revealing trigger for later development of a spatially coincident bAVM. This hypothesis suggests an essential role for endoglin-mediated hemodynamic mechanotransduction in normal corticogenesis.

Iodine-stained fragmented thromboembolism

AIM

Iodine-stained fragmented thromboembolism (ISFT) is a rare phenomenon encountered in the immediate aftermath of mechanical thrombectomy or rarely as a complication of post-carotid stenting. The aim was to describe the imaging appearance and discuss its pathophysiology.

METHOD

This is a retrospective review of patients who underwent mechanical thrombectomy for acute stroke at a single institution over the period of one year. All patients underwent the standard acute stroke imaging protocol (CT head, CT angiogram (CTA) and CT brain perfusion) and when clinically appropriate followed by catheter angiogram and mechanical thrombectomy. ISFT was defined as an arterial luminal filling defect with Hounsfield density equal to or greater than iodine seen on the biplanar CT or conventional CT. The presence and location of ISFT were documented. Standard CT angiogram (CTA) or magnetic resonance angiogram (MRA) was performed 24-48 hours after the neurointerventional procedure to assess for recanalization, volume of infarction and the fate of the ISFT.

RESULTS

ISFTs were identified in eight (five males and three females, age range 18-80 years) out of 49 patients in the following locations: distal M1 (n = 1), M2 (n = 4), M3 (n = 1), A1 (n = 1), distal A2 (n = 1). ISFT and vessel recanalization occurred in five patients on follow-up. ISFT and vessel occlusion persisted in two patients.

CONCLUSION

ISFT is likely the result of mechanical disruption of a thromboembolus, and porosity of the thromboembolus fragment may transiently retain iodinated contrast. Recognition of this entity may be important to aid detection of residual thromboembolism and avoid misinterpretation as calcified thromboembolism.

Idiopathic intracranial hypertension: The veno glymphatic connections

The recent discoveries of the glymphatic and lymphatic systems of the brain have helped advance our understanding of CSF physiology and may allow new insights in the understanding of idiopathic intracranial hypertension (IIH). The clinical and radiologic presentations of IIH appear to be related to congestion of the glymphatic system associated with an overflow of the lymphatic CSF outflow pathway. By revisiting the role of "vascular arachnoid granulations" in the brain, we hypothesize that an initial impairment of the transport of interstitial fluid from the glymphatic system to the venous blood of the dural sinuses may trigger the hydrodynamic cascade of IIH. Furthermore, we speculate that, similar to other water-exchange systems in the brain, a specific subtype of aquaporin is involved in this transport. This theory may eventually help to provide an underlying explanation for IIH and its associated conditions, since in most of them, the expression of several aquaporins is altered.

Efficacy of computed tomography perfusion – Alberta stroke program early computed tomography score for identifying patients with anterior circulation acute ischemic stroke that would benefit from endovascular treatment

Background:

The identification of criteria that improves the selection of ischemic stroke patients most suitable for mechanical thrombectomy (MT) will improve clinical outcomes. The aim of this study was to identify the computed tomography (CT) imaging parameter that best predicts patients who will benefit from endovascular treatment among patients with anterior circulation ischemic stroke.

Materials and Methods:

This retrospective study was conducted in patients with acute middle cerebral artery (MCA) stroke with/without internal carotid artery occlusion who underwent successful MT at Siriraj Hospital from November 2009 to October 2016. Evaluated parameters were compared between those with and without a favorable outcome.

Results:

Forty-four consecutive patients with acute MCA occlusion were included, and 61.4% had unfavorable clinical outcome. Regarding CT perfusion – Alberta stroke program early CT score (CTP-ASPECTS) at the 50% cut point, patients with favorable outcome had higher Cerebral blood volume-ASPECTS (CBV-ASPECTS) and mean transit time-ASPECTS (MTT-ASPECTS) than those with unfavorable outcome. For CTP-ASPECTS at the 75% cut point, patients with favorable outcome had higher CBV-ASPECTS, cerebral blood flow-ASPECTS, and MTT-ASPECTS than those with unfavorable outcome.

Conclusions:

CTP-ASPECTS at the 50% and 75% cut points of abnormality could not predict the clinical outcome of anterior ischemic stroke after thrombectomy. Of the ASPECTS evaluated in this study, MTT-ASPECTS at the 75% cut point was the most predictive parameter. Older age was associated with unfavorable outcome after thrombectomy.

Sentinel Angiographic Signs of Cerebral Hyperperfusion after Angioplasty and Stenting of Intracranial Atherosclerotic Stenosis: A Technical Note

Cerebral hyperperfusion syndrome is a serious complication of endovascular angioplasty and stent placement for long-standing intracranial stenosis, resulting in neurologic dysfunction, seizure, or reperfusion hemorrhage. Rigorous control of blood pressure is commonly used in the perioperative period to prevent cerebral hyperperfusion syndrome, but the optimal blood pressure is often arbitrary. We describe the angiographic features that reflect impaired cerebral autoregulation and microvascular transit abnormality, which may be used to gauge the optimal blood pressure parameters in the immediate postintervention period for prevention of cerebral hyperperfusion syndrome.

Endovascular Thrombectomy for Distal Occlusion Using a Semi-Deployed Stentriever: Report of 2 Cases and Technical Note

Distal intracranial occlusions can sometimes cause significant neurological deficits. Endovascular thrombectomy in these vessels may improve outcome but carry a higher risk of haemorrhagic complications due to the small calibre and tortuosity of the target vessel. We report two cases of isolated M2/3 artery occlusion causing dense hemiplegia that was successfully treated with stent retrieval thrombectomy. A “semi-deployment technique” of a 3 mm stentriever was employed at the M2/3 bifurcation of the middle cerebral artery. Partial stent unsheathing allowed adequate clot engagement while avoiding excessive tension by the stent metal struts along the tortuous course of a distal vessel. Complete revascularization was achieved after first-pass of the stent retriever without complication, resulting in good clinical outcome in both cases. The described semi-deployment technique reduces the radial and tractional force exerted by the stentreiver on small branches, and may reduce the risk of vessel laceration or dissection in distal vessel thrombectomy.

Mechanical thrombectomy in pediatric stroke: systematic review, individual patient data meta-analysis, and case series

OBJECTIVE

The role of mechanical thrombectomy in pediatric acute ischemic stroke is uncertain, despite extensive evidence of benefit in adults. The existing literature consists of several recent small single-arm cohort studies, as well as multiple prior small case series and case reports. Published reports of pediatric cases have increased markedly since 2015, after the publication of the positive trials in adults. The recent AHA/ASA Scientific Statement on this issue was informed predominantly by pre-2015 case reports and identified several knowledge gaps, including how young a child may undergo thrombectomy. A repeat systematic review and meta-analysis is warranted to help guide therapeutic decisions and address gaps in knowledge.

METHODS

Using PRISMA-IPD guidelines, the authors performed a systematic review of the literature from 1999 to April 2019 and individual patient data meta-analysis, with 2 independent reviewers. An additional series of 3 cases in adolescent males from one of the authors' centers was also included. The primary outcomes were the rate of good long-term (mRS score 0-2 at final follow-up) and short-term (reduction in NIHSS score by ≥ 8 points or NIHSS score 0-1 at up to 24 hours post-thrombectomy) neurological outcomes following mechanical thrombectomy for acute ischemic stroke in patients < 18 years of age. The secondary outcome was the rate of successful angiographic recanalization (mTICI score 2b/3).

RESULTS

The authors' review yielded 113 cases of mechanical thrombectomy in 110 pediatric patients. Although complete follow-up data are not available for all patients, 87 of 96 (90.6%) had good long-term neurological outcomes (mRS score 0-2), 55 of 79 (69.6%) had good short-term neurological outcomes, and 86 of 98 (87.8%) had successful angiographic recanalization (mTICI score 2b/3). Death occurred in 2 patients and symptomatic intracranial hemorrhage in 1 patient. Sixteen published thrombectomy cases were identified in children < 5 years of age.

CONCLUSIONS

Mechanical thrombectomy may be considered for acute ischemic stroke due to large vessel occlusion (ICA terminus, M1, basilar artery) in patients aged 1-18 years (Level C evidence; Class IIb recommendation). The existing evidence base is likely affected by selection and publication bias. A prospective multinational registry is recommended as the next investigative step.

Prospective study on embolization of intracranial aneurysms with the pipeline device: the PREMIER study 1 year results

Background

Preliminary clinical studies on the safety and efficacy of the pipeline embolization device (PED) for the treatment of small/medium aneurysms have demonstrated high occlusion rates with low complications.

Objective

To evaluate the safety and effectiveness of the PED for treatment of wide necked small and medium intracranial aneurysms.

Methods

PREMIER is a prospective, multicenter, single arm trial. Patients were treated with the PED for unruptured wide necked aneurysms, measuring ≤12 mm along the internal carotid artery or vertebral artery, between July 2014 and November 2015. At 1 year post-procedure, the primary effectiveness endpoint was complete occlusion (Raymond grade 1) without major parent vessel stenosis (≤50%) or retreatment, and the primary safety endpoint was major stroke in the territory supplied by the treated artery or neurologic death.

Results

A total of 141 patients were treated with PEDs (mean age 54.6±11.3 years, 87.9% (124/141) women). Mean aneurysm size was 5.0±1.92 mm, and 84.4% (119/141) measured <7 mm. PED placement was successful in 99.3% (140/141) of patients. Mean number of PEDs implanted per patient was 1.1±0.26; a single PED was used in 92.9% (131/141) of patients. At 1 year, 97.9% (138/141) of patients underwent follow-up angiography with 76.8% (106/138) of patients having met the study’s primary effectiveness endpoint. The combined major morbidity and mortality rate was 2.1% (3/140).

Conclusions

Treatment of wide necked small/medium aneurysms with the PED results in high rates of complete occlusion without significant parent vessel stenosis and low rates of permanent neurologic complications.

Trial registration

NCT02186561.

012 Mechanical thrombectomy in pediatric stroke: systematic review, individual patient-data meta-analysis, and case series

Introduction

In adults, there is strong evidence demonstrating the superiority of mechanical thrombectomy (MT) plus intravenous thrombolysis over thrombolysis alone for the treatment of acute ischemic stroke due to large vessel occlusion (LVO). The role of MT in the paediatric stroke population is less clear. Here we present an updated systematic review addressing the use of MT in paediatric patients, including three cases from our centre in Sydney, Australia. We have also completed an individual participant data (IPD) meta-analysis of clinical and angiographic outcomes based on these results.

Method

Our systematic review and IPD meta-analysis was performed according to PRISMA-IPD (Preferred Reporting Items for Systematic Reviews and Meta-Analyses: Individual Participant Data) guidelines. Primary outcomes measures were change in NIHSS (National Institute of Health Stroke Scale) score following MT, and mRS (modified Rankin Scale) score at final reported follow-up. The secondary outcome measure was final angiographic result using the mTICI (modified Treatment in Cerebral Ischemia) scale.

Results

MT resulted in good long-term neurological outcomes (mRS 0–2) in 60/67 cases (89.6%;follow-up timing µ=4.1 months: 95%CI 2.9–5.3), good short-term neurological outcomes (reduction in NIHSS by 8 or more points or post-MT NIHSS of 0–1) in 37/52 cases (71.2%), and successful recanalization (mTICI 2b/3) in 57/67 cases (85.1%).

Conclusions

In paediatric patients, MT is an effective treatment for ischaemic stroke due to LVO. In the absence of a dedicated prospective registry and with randomized control trails unfeasible, this report represents the best available evidence for the use of MT in the paediatric setting.