Interventional Neuroradiology Research Articles

Cineangiography versus standard digital subtraction angiography in mechanical thrombectomy: lowering the radiation exposure without sacrificing the outcome

BackgroundEndovascular thrombectomy has become a standard procedure for the treatment of acute ischemic stroke caused by large vessel occlusion. Radiation exposure to the patient and operators during mechanical thrombectomy procedures...

My Short-Term Neurointerventional Training in Thailand Supported by a Women's Observership Program of the World Federation of Interventional and Therapeutic Neuroradiology.

This short report describes my personal experience of 1-month neurointerventional training at Ramathibodi Hospital in Thailand, supported by a women's observership grant from the World Federation of Interventional and Therapeutic Neuroradiology, in which many interventional neuroradiology (INR) fellows from various regions of Thailand also participated. The training program allowed me to experience numerous neurointerventional cases and to acquire skills on how to function as a member of the INR team. This experience prompts me to contemplate the significance of team-based medicine and the role of women in the field of neurosurgery and INR.

Onyx Liquid Embolic Agent: Basic Knowledge for Its Use in Interventional Neuroradiology

Onyx Liquid Embolic Agent: Basic Knowledge for Its Use in Interventional Neuroradiology

Periprocedural management of patients presenting for neurointerventional procedures using flow diverters for complex intracranial aneurysms: An anesthetist's perspective - A narrative review.

Complex intracranial aneurysms pose significant challenges in the realm of neurointervention, necessitating meticulous planning and execution. This article highlights the crucial roles played by anesthetists in these procedures, including patient assessment, anesthesia planning, and continuous monitoring and maintaining hemodynamic stability, which are pivotal in optimizing patient safety. Understanding these complex procedures and their complications will aid the anesthetist in delivering optimal care and in foreseeing and managing the potential associated complications. The anesthetist's responsibility extends beyond the procedure itself to postprocedure care, ensuring a smooth transition to the recovery phase. Successful periprocedural anesthetic management in flow diverter interventions for complex intracranial aneurysms hinges on carefully orchestrating these elements. Moreover, effective communication and collaboration with the interventional neuroradiologist and the procedural team are emphasized, as they contribute significantly to procedural success. This article underscores the essential requirement for a multidisciplinary team approach when managing patients undergoing neurointerventions. In this collaborative framework, the expertise of the anesthetist harmoniously complements the skills and knowledge of other team members, contributing to the overall success and safety of these procedures. By providing a high level of care throughout the periprocedural period, anesthetists play a pivotal role in enhancing patient outcomes and minimizing the risks associated with these intricate procedures. In conclusion, the periprocedural anesthetic management of neurointervention using flow diverters for complex intracranial aneurysms is a multifaceted process that requires expertise, communication, and collaboration.

Fostering collaboration in clinical neuroscience: The evolution of the European Diploma of Interventional Neuroradiology

Fostering collaboration in clinical neuroscience: The evolution of the European Diploma of Interventional Neuroradiology

Navigating the crossroads: Insights into cardiology’s influence on neurointerventional procedures

<p>Since Egaz Moniz introduced angiography, neurovascular interventions have undergone significant advancements. The integration of advanced biomaterials has refined endovascular devices and techniques for complex vascular lesions. The domain of neurointerventions includes neuroendovascular surgery, endovascular neurosurgery, and interventional neurology. Notably, in regions with limited neurointerventional specialists, interventional cardiologists are increasingly treating cerebrovascular strokes. The congruence between coronary and carotid interventions has facilitated the development of adaptable cerebrovascular tools, many inspired by those in cardiac catheter labs. This article provides an overview of key developments in neurointerventions, with a focus on the adaptation of tools between coronary and cerebrovascular procedures.</p>

Anatomical variations in the circle of Willis on magnetic resonance angiography in a south Trinidad population.

This article seeks to determine the prevalence of a complete circle of Willis (CoW) and its common morphological variations in a south Trinidad population, while also investigating the influence of gender, age, and ethnicity on CoW morphology. A prospective, descriptive, cross-sectional study was done on the magnetic resonance images for consecutive patients who had a brain MRI/magnetic resonance angiography at a tertiary health institution in south Trinidad between October 2019 and September 2020. Patients with significant cerebrovascular disease and/or a history of prior neurosurgical intervention were excluded. A complete CoW was seen in 24.3%, with more complete circles observed in younger participants (≤45 years) and Afro-Trinidadians. No gender predilection for a complete CoW was demonstrated. The most common variations in the anterior and posterior parts of the circle were a hypoplastic anterior communicating artery (8.6%, n = 13) and bilateral aplastic posterior communicating arteries (18.4%, n = 28), respectively. Significant variations exist in the CoW of a south Trinidad population with a frequency of complete in 24.3%, and more complete circles in younger patients and Afro-Trinidadians. Gender did not influence CoW morphology. Structural abnormalities in the CoW may be linked to future incidence of cerebrovascular diseases and should therefore be communicated to the referring physician in the written radiology report. Knowledge of variant anatomy and its frequency for a particular populations is also required by neurosurgeons and neuro-interventional radiologists to help with preprocedural planning and to minimize complications.

Comparison between remimazolam and propofol anaesthesia for interventional neuroradiology: a randomised controlled trial

BackgroundGeneral anaesthesia can immobile patients during interventional neuroradiology to improve image quality. Remimazolam, an ultrashort-acting benzodiazepine, is advantageous for haemodynamic stability. This study compared remimazolam and propofol anaesthesia during neuroradiology procedures regarding intraoperative hypotensive events and rapid recovery. MethodsThis single-masked randomised-controlled study included 76 participants who underwent elective endovascular embolisation in a single centre. Patients were randomised between a continuous remimazolam infusion (n = 38) or a target-controlled propofol infusion group (n = 38). In the remimazolam group, flumazenil (0.2 mg) was administered at the end of the procedure. Phenylephrine was titrated to maintain the mean arterial pressure within ± 20% of the baseline value. The primary outcome was the total phenylephrine dose during the procedure. ResultsThe total phenylephrine dose was 0.0 [0.0–30.0] μg in the remimazolam group and 30.0 [0.0–205.0] μg in the propofol group (p = 0.001). Hypotensive events were observed in 11 (28.9%) patients in the remimazolam group and 23 (60.5%) patients in the propofol group (p = 0.001). Recovery times to spontaneous breathing, eye-opening, extubation, and orientation were shorter in the remimazolam group than in the propofol group (all p < 0.001). ConclusionsRemimazolam anaesthesia showed superior haemodynamic stability compared with propofol anaesthesia during neuroradiology procedures. Systematic use of flumazenil enabled rapid recovery from remimazolam anaesthesia. RegistrationUniversity Hospital Medical Information Network Clinical Trials Registry; Registration number: UMIN000047384; URL: https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000054046

The Compensation Index Is Better Associated with DSA ASITN Collateral Score Compared to the Cerebral Blood Volume Index and Hypoperfusion Intensity Ratio

Background: Pretreatment CT Perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the novel compensation index (CI, Tmax &gt; 4 s/Tmax &gt; 6 s) and already established CTP collateral markers, namely cerebral blood volume (CBV) index and Hypoperfusion Intensity Ratio (HIR), with the reference standard American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score (CS) on DSA. Methods: In this retrospective study, inclusion criteria were the following: (a) CT angiography confirmed anterior circulation large vessel occlusion from 9 January 2017 to 10 January 2023; (b) diagnostic CT perfusion; and (c) underwent mechanical thrombectomy with documented DSA-CS. Student t-test, Mann–Whitney-U-test and Chi-square test were used to assess differences. Spearman’s rank correlation and logistic regression analysis were used to assess associations. p ≤ 0.05 was considered significant. Results: In total, 223 patients (mean age: 67.8 ± 15.8, 56% female) met our inclusion criteria. The CI (ρ = 0.37, p &lt; 0.001) and HIR (ρ = −0.29, p &lt; 0.001) significantly correlated with DSA-CS. Whereas the CBV Index (ρ = 0.1, p &gt; 0.05) did not correlate with DSA-CS. On multivariate logistic regression analysis taking into account age, sex, ASPECTS, tPA, premorbid mRS, NIH stroke scale, prior history of TIA, stroke, atrial fibrillation, diabetes mellitus, hyperlipidemia, heart disease and hypertension, only CI was not found to be independently associated with DSA-CS (adjusted OR = 1.387, 95% CI: 1.09–1.77, p &lt; 0.01). Conclusion: CI demonstrates a stronger correlation with DSA-CS compared to both the HIR and CBV Index where it may show promise as an additional quantitative pretreatment CS biomarker.

Large‐Vessel Occlusion Stroke Knowledge and Training for Stroke Severity Assessment Among Emergency Medical Services Personnel in the United States

BACKGROUND Prehospital identification of large‐vessel occlusion (LVO) stroke facilitates the development of a regional triage protocol that could lead to an improvement in intrahospital and interhospital workflows. This requires stroke education of emergency medical services (EMS) personnel to improve stroke recognition, severity assessment, and prenotification. However, the current state of EMS personnel's knowledge of LVO stroke, their training for stroke severity assessment, and their preferences for educational methods are unknown. We conducted a nationwide EMS survey across the United States to glean insights that can inform and customize future EMS educational efforts. METHODS The Society of Vascular and Interventional Neurology, in collaboration with EMS World , created an online questionnaire for EMS personnel. It included 12 multiple‐choice and free‐response questions designed to test participants’ clinical knowledge of LVO, knowledge of stroke center certification levels, prior LVO educational experiences, preferences for educational content delivery, and perspectives on prehospital hurdles to stroke care. All subscribers of EMS World received a survey link via email. RESULTS Of the 38 486 subscribers of EMS World , the survey email was opened by 1830, of whom 1107 completed the survey across all states in the United States, with a response rate of 2.9%. Most of the respondents identified themselves as paramedics/emergency medical technicians (91%). The number of patients with stroke that survey participants transported in the past year was &lt;10 for 618 (56%). Only 285 (26%) participants answered both LVO knowledge questions correctly, and only 128 (12%) respondents correctly identified all types of stroke centers with thrombectomy capability. A total of 362 EMS personnel (33%) denied receiving training to perform LVO severity assessment. Respondents who received training to perform an LVO scale demonstrated nearly twice the prevalence of LVO knowledge (30.6% versus 15.7%; prevalence ratio, 1.94 [95% CI, 1.50–2.53]) than respondents who did not receive training. The top hurdle to prehospital LVO education was identified as the lack of standardized LVO training by 535 (48%) respondents. CONCLUSIONS EMS providers in the United States reported inadequate LVO training and demonstrated gaps in knowledge of LVO, stroke severity scales, and stroke center levels. Systematic efforts to enhance and standardize the educational content and delivery of LVO education are needed.

Angiographic evaluation of the distance from the top of the jugular bulb to the inferior petrosal sinus-internal jugular vein junction: simple classification and identification method for the orifice of the non-visualized inferior petrosal sinus during neuroendovascular surgery.

The inferior petrosal sinus (IPS) is the transvenous access route for neurointerventional surgery that is occasionally undetectable on digital subtraction angiography (DSA) because of blockage by a clot or collapse. This study was aimed at analyzing the distance from the jugular bulb (JB) to the IPS-internal jugular vein (IJV) junction and proposing a new anatomical classification system for the IPS-IJV junction to identify the non-visualized IPS orifice. DSA of 708 IPSs of 375 consecutive patients were retrospectively investigated to calculate the distance from the top of the JB to the IPS-IJV junction, and a simple classification system based on this distance was proposed. The median distance from the top of the JB to the IPS-IJV junction was 20.8 ± 14.7mm. Based on the lower (10.9mm) and upper (31.1mm) quartiles, IPS-IJV junction variants were: type I, 0-10mm (22.3%); type II, 11-30mm (45.8%); type III, > 31mm (23.9%); and type IV, no connection to the IJV (8.0%). Bilateral distances showed a positive interrelationship, with a correlation coefficient of 0.86. The bilateral symmetry type (visualized IPSs bilaterally) according to our classification occurred in 267 of 300 (89.0%) patients. In this study, the IPS-IJV junction was located far from the JB (types II and III), with a higher probability (69.6%). This distance and the four-type classification demonstrated high degrees of homology with the contralateral side. These results would be useful for identifying the non-visualized IPS orifice.

Interdisciplinary rendez-vous approach in endovascular stroke treatment a new concept to accelerate mechanical thrombectomy in primary stroke centers

Abstract Background/Introduction Prompt endovascular treatment of patients with stroke due to intracranial Large Vessel Occlusion (LVO) is a major challenge especially in rural areas because neurointerventionalists are usually not available. As a result, treatment is delayed, and clinical outcomes are worse compared with patients primarily treated in comprehensive stroke centers (CSC). Purpose To address this problem, we present a new concept in which interdisciplinary, on-site endovascular treatment is performed in a Primary Stroke Center (PSC) by a team of interventional cardiologists and neuroradiologists: the Rendez-Vous approach. Methods Twenty-seven patients with LVO who underwent interdisciplinary thrombectomy on-site at the PSC as part of the Rendez-Vous concept were compared with 72 patients who were transferred from a PSCs to the CSC for thrombectomy when diagnosed with LVO in terms of temporal sequences and clinical outcomes. The crucial aspect of the concept is that the patient is not transferred for the intervention but is treated on site and the cardiologist actively starts the intervention while the neurointerventionalist rushes to the site as soon as possible. Results Patients treated on-site at the PSC as part of the Rendez-Vous approach were managed as successfully and without an increase in complication rates compared with patients treated secondarily at a CSC (91.7% successful interventions in Rendez-Vous vs. 87.3% in control group, p=0.57). The time from diagnosis of LVO to groin puncture was reduced by 68.3 minutes with the Rendez-Vous concept (p&amp;lt;0.01). Regarding the clinical outcome, a functionally independent status was achieved in 37.0 % in the Rendez-Vous group and in 19.4% in the control group (p=0.012). Conclusion Interdisciplinary teamwork between cardiology and interventional neuroradiology in rural PSCs leads to shorter times to successful reperfusion in patients with severe ischemic stroke due to LVO. This has a potentially positive impact on the clinical outcome of stroke patients and should be considered as a possible care concept in similar stroke networks.Rendez-Vous concept in stroke management

Abstract 226: Canadian Experience Facilitating a Hands‐on Neurointerventional Workshop for Neurology Trainees

Introduction Neurointerventional radiology is a growing field that has seen innumerable advances in recent years. Unlike the US, which has a sizeable presence of interventional neurologists[1], Canada has disproportionately fewer neurologists in the field of neurointervention. One of the barriers to neurology trainees entering the field of neurointerventional radiology is a lack of exposure during their training. To address this barrier, we conducted the first hands‐on neurointervention workshop focusing on neurology trainees during a Canadian national conference. Though this workshop was open to trainees from neurology, neuroradiology, and neurosurgery, it was conducted in association with the Canadian Stroke Consortium and therefore marketed towards neurology trainees. This pilot hands‐on workshop was the first of its kind in Canada targeting neurology trainees. Methods A 2‐hour workshop was conducted in June, 2023 during a Canadian national conference. The workshop included 3 stations: basic equipment orientation, overview of endovascular techniques for ischemic stroke, and an intracranial aneurysm treatment model treatment station. Participants had an opportunity to rotate through each station at least once. Each station was facilitated by a neurointerventionalist or fellow who demonstrated the techniques and devices to participants. Participants practiced handling wires and catheters, deploying stent‐retrievers, and deploying coils in an aneurysm model, among other essential neurointerventional skills. Participants were asked to voluntarily provide feedback via electronic survey. An electronic survey was emailed to participants, on a voluntary basis; responses were anonymized. Survey results were collected and analyzed using Google Forms. Results Twelve workshop participants consented to participate in the survey and seven completed the entire survey. Respondents were from multiple Canadian neurology residency programs, medical schools, and vascular neurology fellowship programs. Prior to the workshop, most respondents (71.4%) had little‐to‐no knowledge about interventional techniques. Only one respondent answered that their training program provides hands‐on neurointervention experience. Most respondents found the station on endovascular techniques for ischemic stroke to be the most helpful. Prior to the workshop, many respondents had not considered pursuing neurointerventional radiology training. At least one participant responded that they would more favorably consider pursuing neurointerventional radiology following the workshop. Conclusion Increasing neurology trainee exposure to neurointerventional radiology is essential for expanding the number of neurologists entering this field. Events at national and international conferences that provide hands‐on experience are one way to increase exposure. This workshop provided practical experience, particularly in endovascular therapy techniques. All participants had little to no exposure to neurointervention and all favorably rated the workshop. Based on this pilot project, further efforts are needed to incorporate neurointerventional radiology training into Canadian neurology training programs.

Endovascular Treatment in Acute Basilar Artery Occlusion Stroke: A Brief Practice Update From the Society of Vascular and Interventional Neurology

Background The Society of Vascular and Interventional Neurology Guidelines and Practice Standards committee established the “Brief Practice Update” format to provide up‐to‐date recommendations on focused relevant clinical questions. In this Brief Practice Update, we review current evidence and provide recommendations for endovascular treatment (EVT) in patients with acute large‐vessel occlusion of the basilar artery. Methods The Society of Vascular and Interventional Neurology Guidelines and Practice Standards committee conducted a systematic review, including the recent randomized clinical trials of EVT for acute ischemic stroke attributable to basilar artery occlusion, and summarized relevant data to provide recommendations for clinical practice. The Guidelines and Practice Standards quality committee reviewed the findings to ensure adherence to the Society of Vascular and Interventional Neurology internal evidence evaluation guidelines before review by the Society of Vascular and Interventional Neurology board members for societal endorsement. Results Evidence favors EVT for basilar artery occlusion in comparison to medical management alone in patients with moderate to severe stroke. We formulated the level of evidence and the class of recommendation in the context of 5 clinical questions. Conclusions In this brief practice statement, we share general recommendations on EVT for acute ischemic stroke attributable to large‐vessel occlusion of the basilar artery. Recent randomized controlled trials, Basilar Artery Occlusion Chinese Endovascular (BAOCHE) trial and Endovascular Treatment for Acute Basilar‐Artery Occlusion (ATTENTION), and a meta‐analysis of all randomized controlled trials support EVT in patients with moderate to severe basilar artery occlusion stroke symptoms.

Aplicaciones de la tomografía computarizada de haz cónico en procedimientos mínimamente invasivos guiados por imagen

Cone-Beam computed tomography (CBCT) obtains three-dimensional images using a two-dimensional detector. The use of CBCT in treatment planning and evaluation increases the safety and efficacy of minimally invasive procedures. This article reviews the technical considerations, main clinical applications, and future directions of CBCT in vascular and interventional radiology and interventional neuroradiology.

Measurement of Neutrophil Gelatinase-Associated Lipocalin (Ngal) Following Neuroradiological Procedure/s in Patients with Aneurysmal Subarachnoid Hemorrhage: A Preliminary Study.

Radiocontrast administration during interventional neuroradiology (INR) procedures for aneurysmal subarachnoid haemorrhage (aSAH) can add to renal insult. Serum creatinine (sCr) is a conventional marker of acute kidney injury (AKI). Serum neutrophil gelatinase-associated lipocalin (sNGAL) is a novel marker which is increasingly used to predict renal injury in susceptible patients. The primary aim of this study was to evaluate correlation between serum neutrophil gelatinase-associated lipocalin (NGAL) and sCr in aSAH patients undergoing therapeutic or diagnostic INR procedures. The secondary aim was to find the incidence of contrast-induced AKI and hemodynamic complications during the study period. All consenting aSAH patients (18-60 years, Modified Hunt and Hess grade 1-4) posted for INR procedures during the study time were included. Patients with history of chronic renal disease, recent contrast exposure, or renal insufficiency were excluded. Blood samples for sCr and sNGAL were obtained preprocedure and then at 1, 6, 24, and 48 h after contrast administration. Hourly urine output was noted. AKI was defined by KDIGO guidelines. Repeated measurement analysis of variance, Posthoc Bonferroni test and Pearson correlation coefficient test. Fifty patients, mean age 47.34 ± 9.31 years, were enrolled for the study. Majority (48; 96%) were Hunt and Hess (H and H) grade I-III. The mean volume of contrast administered was 123.2 ± 53.08 mL. The mean sNGAL and sCr values at pre-op, 1, 6, 24, and 48 h were 124.99 ± 64.58, 148.40 ± 77.90, 147.33 ± 76.00, 125.49 ± 64.44, and 116.38 ± 61.79 ng/mL and 0.629 ± 0.23, 0.624 ± 0.22, 0.612 ± 0.21, 0.632 ± 0.19, and 0.577 ± 0.22 mg/dL, respectively. There was a correlation in sCr and sNGAL value (P < 0.001) at all study time points. However, no specific pattern was seen. No patient developed any AKI or hemodynamic complications in first 48 h. There is a correlation between serum NGAL and sCr at individual time points. NGAL may represent a sensitive early biomarker of renal impairment after INR Procedures. There was no incidence of AKI after contrast administration in aSAH patients without predisposing renal risk factors.

Abstract 231: Rescue Stenting for Failed Mechanical Thrombectomy in Acute Ischemic Stroke:An Analysis of the SVIN Registry

Introduction Mechanical thrombectomy (MT) often fails to achieve successful reperfusion in up to 20% of acute ischemic stroke (AIS) patients with large vessel occlusion (LVO) [1, 2]. Rescue strategies options, including balloon angioplasty alone, rescue stenting (RS) alone, or stent with balloon angioplasty, have shown promise in observational studies and meta‐analyses [3, 4]. We aimed to evaluate the association between RS with functional outcomes compared to medical management (MM) in anterior circulation LVO‐AIS patients who underwent failed MT. Methods This retrospective cohort study utilized prospectively collected data from the Society of Vascular and Interventional Neurology (SVIN) Registry, including adult patients with AIS who experienced a failed MT at 14 comprehensive stroke centers. A failed MT was defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score of 0 to 2a after multiple attempts to clot retrieval. The patients were divided into two groups: those who received RS and those who only received MM. The primary efficacy outcome was the shift in the degree of disability, as measured by the modified Rankin Scale (mRS), at 90 days. Additional outcomes included functional independence (defined as a 90‐day mRS score of 0‐2), symptomatic intracranial hemorrhage (sICH), and mortality at 90 days. These outcomes were assessed using uni‐ and multivariable logistic regression models. Results A total of 642 patients were included in the analysis. The RS group consisted of 294 (45.8%) patients, while the MM group comprised 348 (54.2%) patients. A mTICI score of 2b‐3 was achieved in 242/293 (82.6%) patients in the RS group. Compared to the MM group, the RS showed a favorable shift in the overall 90‐day mRS distribution (adjusted common odds ratio [OR]=1.97, 95% CI 1.36–2.85, p=&lt;0.001), higher rates of functional independence (RS: 30.7% vs. MM: 12%, adjusted OR [aOR]=2.39, 95% CI 1.34‐4.26, p=0.003), lower rates of sICH (RS: 2.7% vs. MM: 9%, aOR=0.32, 95% CI 0.14‐0.71, p=0.005), and lower 90‐day mortality (RS: 29.5% vs. MM: 49.7%, aOR=0.49, 95% CI 0.33‐0.74, p=&lt;0.001). Conclusion RS showed promising functional outcomes compared to MM. RS was associated with improved functional independence, reduced sICH rates, and lower 90‐day mortality. The RS group exhibited a favorable shift in the 90‐day mRS distribution, indicating better overall functional outcomes. These findings support RS as a potential rescue strategy for AIS patients with failed MT, with implications for clinical decision‐making. However, further prospective studies are needed to validate these observations and optimize outcomes.

Abstract 078: Managing Clopidogrel Resistance in Neurointervention: Surveying Current Approaches

Introduction Due to the variability in patient responses to clopidogrel, adjusting antiplatelet regimen based on platelet function testing has become a widespread practice to reduce thromboembolic complications in neurointervention. In the absence of standardized guideline, we aimed to explore the practice patterns related to clopidogrel resistance. Methods We conducted a survey targeting neurointerventionalists, comprising multiple‐choice questions and opportunities for free‐text responses when necessary. The survey was distributed via a professional society – the Society of Vascular and Interventional Neurology (SVIN) and two emailing lists – WovenEndoBridge and Neurointerventional Research Consortium. The data obtained from the responses were analyzed using descriptive statistics. Results A total of 133 neurointerventionalists representing 83 institutions within 24 countries responded to the survey. 62% of respondents tested for clopidogrel resistance prior to any neurovascular stent placements. 80% utilized VerifyNow point‐of‐care P2Y12 assay; other assays included multiplate analyzer, platelet function analyzer (PFA‐100), and CYP2C19 genotype assay. Respondents reported 25 different therapeutic thresholds, with the P2Y12 Reaction Units range between 60 and 180 most commonly used (16.4%). 61% reported they would switch to ticagrelor in the case of persistent resistance. On the other hand, when patients are supratherapeutic, 48% did not make any changes while 42% reduced clopidogrel dose. Finally, 93% felt that there was a lack of well‐established protocol for management of clopidogrel resistance. Conclusion Neurointerventional practice patterns around clopidogrel resistance remains heterogeneous. Our results underscore the need for evidence‐based guidance on anti‐thrombotic management during cerebrovascular stenting.

Abstract 056: Patterns of Care in the Management of Intracranial Atherosclerosis‐related Large Vessel Occlusion–the RESCUE‐LVO survey

Introduction Intracranial atherosclerosis‐related large vessel occlusion (ICAS‐LVO) is a common cause of failed mechanical thrombectomy (MT) in acute ischemic stroke (AIS) [1]. Treatment of ICAS‐LVO with rescue stenting and/or angioplasty has shown promising outcomes, but diagnosing ICAS‐LVO during MT can be challenging [2, 3]. There are uncertainties regarding optimal approaches, techniques, and timing for treating ICAS‐LVO. To understand current practice patterns and address these uncertainties, we conducted a survey among neurointerventional practitioners experienced in ICAS‐LVO management during MT. Methods We conducted an international online survey of neurointerventionalist members of the Society of Neurointerventional Surgery (SNIS) and the Society of Vascular and Interventional Neurology (SVIN). The 28‐question poll evaluated the preferences on diagnosis, treatment, and endovascular approach to ICAS‐LVO. Results 168 individual survey responses were obtained from practicing neurointerventional physicians. Overall, 40.6% reported an incidence of 6–10% of ICAS‐LVO during MT. Most neurointerventionalists (91%) diagnose ICAS‐LVO after a continued or recurrent occlusion or by the presence of fixed focal stenosis (FFS) after multiple MT attempts. Most respondents (86%) preferred acute treatment of ICAS‐LVO with rescue stenting (RS) +/‐ angioplasty. However, in patients who achieved recanalization with a severe FFS, the majority (44%) recommended maximal medical management only. The preferred medication during acute RS was intravenous antiplatelet therapy (69%), and after acute RS was dual oral antiplatelet therapy (58%). Fear of hemorrhagic complications (70%) was the most compelling reason not to perform RS +/‐ angioplasty. Twenty‐five percent of respondents were hesitant to randomize patients to acute RS versus medical therapy in a future randomized trial because of the lack of sensitive and specific biomarkers to diagnose ICAS‐LVO before MT treatment. Conclusion Our survey highlights the significant variability and uncertainty in the diagnosis and management of ICAS‐LVO during MT among neurointerventional practitioners. There is no equipoise regarding the optimal treatment strategy, and the fear of hemorrhagic complications associated with antithrombotic medications contributes to the variation in practice. Our survey underscores the need for future research and randomized clinical trials to address the uncertainties in the management of ICAS‐LVO during MT. Improved imaging biomarkers and consensus guidelines are essential to guide clinical decision‐making and optimize patient outcomes in this challenging population of AIS patients.

Abstract 162: Indirect Carotid Cavernous Fistula with Oculomotor Nerve Palsy Secondary to Trauma

Introduction Intriguing and uncommon, we present a fascinating case of carotid‐cavernous fistula (CCF) following ocular trauma. Delving into medical nuances and outcomes, this reported case offers valuable insights for clinicians and researchers in the field of ophthalmology and interventional Neurology. Methods An elderly patient presented to the emergency department with diplopia and left eyelid ptosis two weeks after left ocular trauma. The patient had exotropia and hypotropia with restricted movement in all directions but mostly during adduction and infraduction which led to the diagnosis of oculomotor nerve palsy. Computer Tomography (CT) head was obtained which showed mild left proptosis with the prominence of the optic nerve sheath complex, CT angiography revealed asymmetric prominence of the left ophthalmic veins and enlarged left cavernous sinus with outward convex borders. CT face and mandible with IV contrast did not show any bony deformity. The patient underwent cerebral angiography that showed an indirect type 4 cavernous‐carotid fistula. Results A precise incidence of CCF fistula has not been reported so far in the literature but it is estimated to be present in 0.2 % of patients presenting with traumatic brain injury with an increased incidence of 4 % with basilar skull fractures. They can occur spontaneously or following closed skull injury, skull base fractures, or iatrogenically after craniotomies, endoscopic transsphenoidal or sinus surgery, and endovascular procedures. They can be classified based on angiographic arterial architecture (direct or indirect), hemodynamics (high flow or low flow), and etiology (spontaneous or traumatic). Type A are direct fistulas, whereas types B, C, and D are indirect fistulas. Direct CCFs often present with pulsatile exophthalmos, orbital bruit, chemosis, diplopia, ocular redness, orbital pain, swelling, swishing or buzzing sounds, headache, or vision loss. Indirect low‐flow CCFs may be asymptomatic and insidious in onset and mostly present with chemosis and conjunctival injection. Conclusion Indirect carotid‐cavernous fistula rarely occurs secondary to a head trauma without any bony deformity and it's even rare to have an oculomotor nerve palsy on presentation, it should be considered as an etiology when evaluating patients for ocular nerve palsies.