Posterior Circulation Research Articles

General anesthesia vs. conscious sedation and local anesthesia for endovascular treatment in patients with posterior circulation acute ischemic stroke: An updated systematic review and meta-analysis

IntroductionThe best anesthetic choice for patients with acute posterior circulation stroke during endovascular treatment (EVT) remains uncertain. MethodWe searched five databases to identify studies that met the inclusion criteria. Our primary outcome measure was functional independence (FI). Secondary outcomes were 3-month mortality, any intracranial hemorrhage (ICH), symptomatic ICH (sICH), successful reperfusion, and procedure- and ventilator-associated complications. ResultsA total of 10 studies were included in our meta-analysis. No significant differences were detected between the general anesthesia (GA) and conscious sedation and local anesthesia (CS/LA) groups in 3-month FI (nine studies; OR=0.69; 95% CI 0.45–1.06; P=0.083; I2=66%;), 3-month mortality (nine studies; OR=1.41; 95% CI 0.94–2.11; P=0.096; I2=61.2%;), any ICH (three studies; OR=0.75; 95% CI 0.44–1.25; P=0.269; I2=0%;), or sICH (six studies; OR=0.64; 95% CI 0.40–1.04; P=0.073; I2=0%;). No significant differences were observed for successful reperfusion (10 studies; OR=1.17; 95% CI 0.91–1.49; P=0.219; I2=0%;), procedure-related complications (four studies; OR=1.14; 95% CI 0.70–1.87; P=0.603; I2=7.9%;), or respiratory complications (four studies; OR=1.19; 95% CI 0.61–2.32; P=0.616; I2=64.9%;) between the two groups. ConclusionsOur study showed no differences in 3-month FI, 3-month mortality, and successful reperfusion between patients treated with GA and those treated with CS/LA. Additionally, no increased risk of hemorrhagic transformation or pulmonary infection was observed in the CS/LA group. These results indicate that CS/LA may be an EVT option for acute posterior circulation stroke patients.

Posterior cerebral territory ischemia in pediatric moyamoya: Surgical techniques and long-term clinical and radiographic outcomes.

To describe a surgical technique for posterior cerebral revascularization in pediatric patients with moyamoya arteriopathy. Here, we describe the clinical characteristics, surgical indications, operative techniques, and clinical and radiographic outcomes in a series of pediatric patients with moyamoya disease affecting the posterior cerebral artery (PCA) territory. A retrospective single-center series of all pediatric patients with moyamoya disease who presented to our institute between July 2009 through August 2019 were reviewed. The clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic outcomes of pediatric moyamoya patients with PCA territory ischemia were collected and analyzed. A total of 10 PCA revascularization procedures were performed in 9 patients, 5 female, ages 1 to 11.1years (average 5.2years). Complications included 1 stroke, with no infections, hemorrhages, seizures, or deaths. One patient had less than 1year of radiographic and clinical follow-up. In 8 of 9 patients with at least 1year of radiographic follow-up, there was engraftment of surgical vessels present in all cases. No new strokes were identified on long-term follow-up despite the radiographic progression of the disease. In the 8 cases available for analysis, the average follow-up was 50.8months with a range of 12 to 117months. PCA territory ischemia in patients with progressive moyamoya disease can be surgically treated with indirect revascularization. Here, we describe our experience with PCA revascularization procedures for moyamoya disease, including pial pericranial dural (PiPeD) revascularization and pial synangiosis utilizing the occipital artery. These surgical options may be useful for decreasing the risk of stroke in pediatric moyamoya patients with severe posterior circulation disease.

Dynamic and visual nomograms to online predict unfavorable outcome of mechanical thrombectomy for acute basilar artery occlusion.

The evidence of mechanical thrombectomy (MT) in basilar artery occlusion (BAO) was limited. This study aimed to develop dynamic and visual nomogram models to predict the unfavorable outcome of MT in BAO online. BAO patients treated with MT were screened. Preoperative and postoperative nomogram models were developed based on clinical parameters and imaging features. An independent dataset was collected to perform external validation. Web-based calculators were constructed to provide convenient access. A total of 127 patients were included in the study, and 117 of them were eventually included in the analysis. The nomogram models showed robust discrimination, with an area under the receiver operating characteristic (ROC) of 0.841 (preoperative) and 0.916 (postoperative). The calibration curves showed good agreement. The preoperative predictors of an unfavorable outcome were previous stroke, the National Institutes of Health Stroke Scale (NIHSS) at admission, and the posterior circulation Alberta Stroke Program Early Computed Tomography Score (pc-ASPECTS). The postoperative predictors were previous stroke, NIHSS at 24h, and pc-ASPECTS. Dynamic and visual nomograms were constructed and validated for the first time for BAO patients treated with MT, which provided precise predictions for the risk of an unfavorable outcome. The preoperative model may assist clinicians in selecting eligible patients, and the postoperative model may facilitate individualized poststroke management.

The Role of Cisternostomy and Cisternal Drainage in the Treatment of Aneurysmal Subarachnoid Hemorrhage: A Comprehensive Review.

Aneurysmal subarachnoid hemorrhage (aSAH) provokes a cascade reaction that is responsible for early and delayed brain injuries mediated by intracranial hypertension, hydrocephalus, cerebral vasospasm (CV), and delayed cerebral ischemia (DCI), which result in increased morbidity and mortality. During open microsurgical repair, cisternal access is achieved essentially to gain proximal vascular control and aneurysm exposition. Cisternostomy also allows brain relaxation, removal of cisternal clots, and restoration of the CSF dynamics through the communication between the anterior and posterior circulation cisterns and the ventricular system, with the opening of the Membrane of Liliequist and lamina terminalis, respectively. Continuous postoperative CSF drainage through a cisternal drain (CD) is a valuable option for treating acute hydrocephalus and intracranial hypertension. Moreover, it efficiently removes the blood and toxic degradation products, with a potential benefit on CV, DCI, and shunt-dependent hydrocephalus. Finally, the CD is an effective pathway to administer vasoactive, fibrinolytic, and anti-oxidant agents and shows promising results in decreasing CV and DCI rates while minimizing systemic effects. We performed a comprehensive review to establish the adjuvant role of cisternostomy and CD performed in cases of direct surgical repair for ruptured intracranial aneurysms and their role in the prevention and treatment of aSAH complications.

Endovascular Treatment May Be Effective in Preventing Recurrence of Ischemic Stroke in Vertebral Artery Stump Syndrome: A Case Series.

Vertebral artery stump syndrome (VASS) is a rare condition that can cause posterior circulation ischemic stroke due to occlusion of the ipsilateral vertebral artery (VA) orifice, resulting in blood flow stagnation and embolus formation. Although there is no established treatment for this condition, we observed 3 cases of VASS out of 326 acute ischemic stroke cases at a single institution from April 2021 to October 2022. Despite the best possible antithrombotic treatment, all 3 patients had recurrent ischemic strokes. One patient underwent drug-eluting stenting of the VA orifice to relieve occlusive flow. The other 2 patients received coil embolization, which resulted in the disappearance of their culprit collateral flow. None of the patients had recurrent ischemic strokes after endovascular intervention. Based on our observations, stenting and coil embolization are effective methods for preventing future recurrences of VASS.

WITHDRAWN: A narrative review of techniques for surgical revascularization of the extracranial vertebral artery in vertebrobasilar insufficiency

Vertebrobasilar insufficiency is a condition characterized by poor blood flow through the posterior circulation of the brain, which supplies the brainstem, thalamus, hippocampus, cerebellum, occipital lobes, and medial temporal lobes. Narrowing or occlusion of the vertebral arteries may be result in a range of neurological symptoms, including dizziness, imbalance, dysarthria, and even stroke. If symptomatic patients fail medical management, revascularization of the vertebral artery should be considered. Restoration of blood flow may involve transluminal balloon angioplasty or stent placement; however, certain cases may still require surgical intervention. The complexity of surgical revascularization of the vertebral artery requires careful consideration of skull base and neck anatomy. This review article will focus on bypass of the vertebral artery in the setting of ischemic pathology, describing the technique, anatomical nuances, steps involved in preoperative planning, and postoperative management.

A Systematic Review and Meta-Analysis of Vertebral Artery Injury After Cervical Spine Trauma.

Systematic Review and Meta-Analysis. Identify the incidence, mechanism of injury, investigations, management, and outcomes of Vertebral Artery Injury (VAI) after cervical spine trauma. A systematic review and meta-analysis were conducted in accordance with the PRISMA guidelines (PROSPERO-ID CRD42021295265). Three databases were searched (PubMed, SCOPUS, Google Scholar, CINAHL PLUS). Incidence of VAI, investigations to diagnose (Computed Tomography Angiography, Digital Subtraction Angiography, Magnetic Resonance Angiography), stroke incidence, and management paradigms (conservative, antiplatelets, anticoagulants, surgical, endovascular treatment) were delineated. Incidence was calculated using pooled proportions random effects meta-analysis. A total of 44 studies were included (1777 patients). 20-studies (n = 503) included data on trauma type; 75.5% (n = 380) suffered blunt trauma and 24.5% (n = 123) penetrating. The overall incidence of VAI was .95% (95% CI 0.65-1.29). From the 16 studies which reported data on outcomes, 8.87% (95% CI 5.34- 12.99) of patients with VAI had a posterior stroke. Of the 33 studies with investigation data, 91.7% (2929/3629) underwent diagnostic CTA; 7.5% (242/3629) underwent MRA and 3.0% (98/3629) underwent DSA. Management data from 20 papers (n = 475) showed 17.9% (n = 85) undergoing conservative therapy, anticoagulation in 14.1% (n = 67), antiplatelets in 16.4% (n = 78), combined therapy in 25.5% (n = 121) and the rest (n = 124) managed using surgical and endovascular treatments. VAI in cervical spine trauma has an approximate posterior circulation stroke risk of 9%. Optimal management paradigms for the prevention and management of VAI are yet to be standardized and require further research.

Basilar artery bifurcation anatomy as a determinant of recanalization and stroke outcome: Basilar artery bifurcation anatomy and stroke outcome

ObjectivesThrombectomy improves outcomes in patients with basilar artery (BA) occlusion. We hypothesized that the anatomic configuration of the BA bifurcation, classified as T- or Y-shaped, may impact the outcome as a T-shaped BA would involve more deep penetrating arteries of the midbrain and thalamus. Materials and methodsIn this 2-center retrospective cohort study, we included patients with stroke due to distal BA occlusion and performed blinded classification of their BA distal bifurcation as either T- or Y-shaped. The primary outcomes were favorable outcome at 90-days (modified Rankin Scale 0 – 2) and successful recanalization (TICI scores 2B or 3). Results70 patients (mean age 66 years, 36% women) were included. 38 had T- and 32 had Y-shaped bifurcations. Baseline characteristics were similar for both groups, including demographics, onset to arterial puncture time, baseline NIHSS, THRIVE score, posterior circulation collateral score, and presence of tandem occlusion. Comparing the T- to the Y- shape, there was no difference in the likelihood of successful recanalization (RR: 1.02, CI: [0.86–1.21], p=1.00) nor 90-day favorable mRS (0-2) score (RR: 0.58, CI: [0.25–1.32]; p=0.18). Similarly, mortality at 30 and 90-days were not significantly affected by the type of bifurcation. ConclusionsThe configuration of the basilar artery does not significantly impact on recanalization success or stroke outcome in our study. Further studies are needed to confirm our observations.

Abstract 123: First Off‐Label Use of the XIENCE Skypoint Stent for Mechanical Thrombectomy Rescue

Introduction Despite technical advances in mechanical thrombectomy (MT), failure to achieve recanalization in the posterior circulation remains a significant challenge. Rescue strategies to increase MT success in the posterior circulation have been explored. We demonstrate the first successful off‐label use of XIENCE Skypoint™ (Abbott), a balloon‐mounted drug‐eluting stent (DES), for intracranial MT rescue in the posterior circulation. Methods Case report and endovascular technique. Results A 52‐year‐old man with hypertension, hyperlipidemia, and deep venous thrombosis who presented with acute ischemic stroke in bilateral occipital, lateral pons, and cerebellar regions. Computed tomography angiography (CTA) showed bilateral vertebral artery occlusion consistent with a history of dissection in the setting of cervical manipulation. Admission National Institutes of Health Stroke Scale (NIHSS) 20. Last known well less than 12 hours from presentation. Intravenous thrombolysis was deferred as the patient was on pre‐admission anticoagulants. Mechanical thrombectomy failed after several unsuccessful passes (Fig 1). XIENCE Skypoint™ stent was deployed within the left vertebral artery (V4 segment) with restoration of flow preceded by eptifibatide drip (Fig 2). Repeat CTA at six months showed patent left vertebral and basilar arteries. Conclusion Rescue stenting using DES may be a successful and safe therapeutic intervention for challenging failed MT. The off‐label use of DES for intracranial pathologies continues to expand. This is the first case report in the literature describing successful rescue stenting using XIENCE Skypoint™ in the posterior circulation. Further investigation is warranted to fully elucidate the risks and benefits of this treatment approach.

Abstract 225: Rescue Stenting for Posterior Circulation Strokes

Introduction Intracranial atherosclerotic disease (ICAD) is associated with up to 32% of posterior circulation strokes.1 ICAD‐related strokes are at high risk for re‐occlusion following MT. Rescue treatment with stenting, balloon angioplasty, and/or intraarterial thrombolysis or antiplatelets are often required to treat the underlying stenosis. However, these rescue treatments are associated with their own risks.2,3 The SAMMPRIS trial reported that percutaneous transluminal angioplasty and stenting (PTAS) was associated with inferior outcomes compared to aggressive medical management alone but it is unclear whether these findings are generalizable to LVO strokes.4 Recent literature has reported clinical benefits associated with rescue stenting in the setting of ICAD‐related MT‐refractory strokes.5 However, most of the existing literature focuses on anterior circulation. This meta‐analysis aims to analyze the literature regarding the efficacy and safety of post‐thrombectomy PTAS in ICAD‐related posterior circulation strokes. Methods The search strategy was developed following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines.6 Using the common evidence medicine framework PICOS (Patient Population, Intervention, Control/Comparison, Outcome, and Study type), we specified our research question: “In patients with posterior circulation AIS who underwent endovascular thrombectomy but failed to recanalize or who had severe stenosis, is PTAS an effective and safe rescue treatment option?” An electronic search of PubMed, EMBASE, Cochrane and OVID databases was performed from date of database inception to March 2023. Data was collected and analyzed using “Meta” package in RStudio.7 Outcomes of interest included 90 day modified Rankin score (mRS) and 90‐day mortality. Results A total of 10 studies were collected, but only 7 double‐arm studies involving 965 participants were included in this analysis. Among these patients, 544 underwent rescue stenting, while 421 were control patients. In a common effects meta‐analysis, patients who underwent stenting were more likely to have an mRS ≤ 2 at 90 days (OR 1.73, 95% CI [1.25 – 2.37]; p < 0.001) and lower odds of mortality at 90 days (OR 0.31, 95% CI [0.23 – 0.42]; p < 0.001). Additionally, patients undergoing stenting were less likely to have symptomatic intracranial hemorrhage (sICH) (OR 0.34, 95% CI [0.17 ‐ 0.67]; p = 0.002). Furthermore, the stenting group showed significantly higher odds of achieving a modified treatment in cerebral ischemia score (mTICI) of 2b‐3 when compared to the control group (OR 11.32, 95% CI [6.54 ‐ 19.59]; p < 0.001). Conclusion PTAS appears to be an effective and safe treatment for ICAD after MT in the posterior circulation both improving likelihood of good outcomes and overall survival. Given the uncertainty of applying the results of the SAMMPRIS trial to LVOs, further research is needed to better assess the efficacy and safety of PTAS in this patient population.

Abstract 038: Fusiform/Dissecting vs. Saccular Posterior Circulation Aneurysms Treated with Flow Diversion: A Multicenter Study

Introduction Flow diverters have demonstrated reliable safety and effectiveness for the treatment of selected anterior circulation intracranial aneurysms. However, posterior circulation aneurysms comprise around 10‐15% of all aneurysms, and they frequently present atypical morphological and anatomical characteristics. Furthermore, these lesions have an increased risk of rupture (compared to those in the anterior circulation) with respect to size and higher treatment risks (regardless of the technique). Flow diversion in posterior circulation aneurysms has been described previously with inconsistent clinical and radiological results. Hence, we aimed to compare the safety and effectiveness of FDs in fusiform/dissecting vs. saccular aneurysms located in the vertebrobasilar vessels. Methods We performed a multicenter, retrospective cohort study including 9 centers. All patients treated with FDs for aneurysms located in the posterior circulation (vertebral and basilar arteries) between 2015 and 2022 were included. Patients were divided into two groups according to the morphology of the aneurysm (fusiform/dissecting vs. saccular). The effectiveness outcome was complete aneurysm occlusion (Raymond‐Roy Class 1) at the latest follow‐up. Safety outcomes included the incidence of ischemic/hemorrhagic and mortality. After adjusting for confounders multivariable logistic regressions were performed to compare outcomes of interest. Results A total of 147 patients with 147 aneurysms were included. The fusiform/dissecting group included 85 cases, while the saccular group 62. The saccular group had older patients (median age: fusiform/dissecting, 55 years [45‐64] vs. saccular, 63 years [51‐70.0]; p=.02). The number of female patients was not different between groups (fusiform/dissecting, 42% vs. saccular, 58%; p=.05). Clinical presentation, comorbidities, modified Fisher, and Hunt and Hess were similar. Baseline modified Rankin Score (mRS) was different (mRS 0‐2: fusiform/dissecting, 84% vs. saccular, 98%; p=.030). Previous endovascular treatment (p=.396) was similar. Aneurysm location (most were in the vertebral artery: fusiform/dissecting, 60% vs. saccular, 42%; p=.009) was different. Median aneurysm size (fusiform/dissecting, 10.0 mm [6.5‐18.8] vs. saccular, 5.9 [3.0‐10.0]; p=<.001), and proximal (fusiform/dissecting, 3.6 mm [2.7‐4.1] vs. saccular, 2.8 [2.4‐3.3]; p=<.001) and distal landing (fusiform/dissecting, 3.2 mm [2.5‐3.5] vs. saccular, 2.4 [2.0‐3.0]; p=<.001) zones were different. The number of FDs per patient (>1 FD: fusiform/dissecting, 36% vs. saccular, 10%; p=<.001) and adjunctive coiling (fusiform/dissecting, 89% vs. non‐F, 74%; p= .015) were different. The most commonly implanted was Pipeline Flex (fusiform/dissecting, 55%, vs. saccular, 40%). Thromboembolic (fusiform/dissecting, 8.2%, vs. saccular, 8.1%; p=.97) and hemorrhagic (fusiform/dissecting, 4%, vs. saccular, 10%; p=.125). Mortality was increased in the fusiform/dissecting group (19%) vs saccular (12%) but not different (p=.365). At an overall median follow‐up time of 13.5 [7.4‐28.8] months, complete occlusion was lower in the fusiform/dissecting group (61% vs. F, 63%) but not statistically different (p=.356). Follow‐up mRS was not different (mRS 0‐2: fusiform/dissecting, 73% vs. saccular, 76%; p=.365). 172 (71%) of the cases achieved complete aneurysm occlusion. Multivariable analysis showed that age (OR: 0.96; 95%CI: 0.93‐0.99; p=.008) and location in the basilar artery (OR: 0.09; 95%CI: 0.03‐0.29; p=<.001) were associated with incomplete occlusion at follow‐up. Conclusion Our results suggest that flow diversion can be an effective treatment for fusiform/dissecting and saccular aneurysms located in the posterior circulation. Although the occlusion rates after flow diversion in fusiform/dissecting aneurysms showed a lower rate compared to saccular, the favorable safety profile of FDs allows them to be considered a valuable tool in the neuroinventionalist armamentarium.

Abstract 235: General Anesthesia vs. Non‐General Anesthesia in Endovascular Treatment for Patients with Acute Ischemic Stroke

Introduction Current evidence supports endovascular therapy (EVT) for eligible patients with acute ischemic stroke in the anterior and posterior circulation. However, there is no consensus regarding the choice of anesthetic approach during EVT and early reported studies were observational with potential biases and confounding. Therefore, we sought to build concrete evidence from randomized clinical trials (RCTs) comparing the general anesthesia (GA) vs. non‐GA via a systematic review and meta‐analysis approach. Methods Data from inception to June 2023 were reviewed and only RCTs comparing the GA vs. non‐GA were included. We then pooled data for the main procedural, safety, and efficacy outcomes with odds ratios (ORs) and 95% CI for dichotomous data and mean difference (MD) with 95% CI for continuous data under random effect model. Results Eight RCTs were included in the final analysis (n=1203) with seven of them reporting data for the anterior circulation (n=1116) and one for the posterior circulation (n=87). Regarding efficacy outcomes, pooled results revealed non‐statistically significant difference between GA and non‐GA for functional independence at 90 days defined as modified Rankin Score scale of 0‐2 (OR = 1.17, 95% CI: 0.88–1.56, P= 0.28; I2 = 26%, Figure A) and the results of the anterior circulation subgroup showed non‐statistically significant difference (OR = 1.22, 95% CI: 0.90–1.67, P= 0.2; I2 = 31%) and the difference was not also evident for posterior circulation (48.8% vs 54.5%; RR, 0.89; 95% CI, 0.58‐1.38; adjusted OR, 0.91; 95% CI, 0.37‐2.22). Successful recanalization, defined as Thrombolysis in Cerebral Infarction score of 2b‐3, showed a statistically significant results favoring GA over non‐GA (OR = 1.94, 95% CI: 1.42–2.63, P=0.0001; I2 = 0%, Figure B) and this continued to show statistically significant in both anterior and posterior circulation subgroups. Onset to reperfusion time was not statistically significant between GA and non‐GA (MD, ‐2.59; 95% CI: ‐22.38 to 17.21, P= 0.8; I2=24%, Figure C). Regarding safety outcomes, there were no statistically significant differences in intracranial hemorrhage (OR = 0.95, 95% CI: 0.67–1.35, p = 0.79; I2 =0%, Figure D) or mortality (OR = 0.95, 95% CI: 0.71–1.29, p = 0.76; I2 =0%, Figure E). However, GA showed a higher risk of hypotension compared to non‐GA (OR = 6.05, 95% CI: 3.25–11.25, P=0.00001; I2 =69%, Figure F). Sensitivity analysis by leave one out removing Ren et al (5) showed homogenous results (OR = 8.43, 95% CI: 5.85–12.16, P=0.00001; I2 =0%) Conclusion In this study‐level meta‐analysis, GA resulted in higher rates of successful reperfusion as compared to non‐GA despite being associated with higher rates of hypotension. Since many of the included studies were small and single center, more studies are warranted to support these findings.

Abstract 124: Vertebral Artery Web as a Rare Cause of Ischemic Stroke in a young male

Introduction Vertebral artery web has been rarely identified compared to the frequently reported, carotid artery web as etiology of ischemic stroke. Here we present a young patient with symptomatic vertebral artery web. Methods Case Report Results 35‐year‐old male presented with persistent, intermittent, bilateral visual scintillations lasting 30‐60 seconds for one month. Neurological examination positive for bi nasal superior quadrantanopia. Computed tomography (CT) of head showed patchy hypo density in right posterior circulation artery (PCA) territory. Magnetic resonance imaging (MRI) showed restriction diffusion over bilateral PCA territories right greater than left (image A). MR Angiogram head and neck showed abnormal contour within right vertebral artery in V2 segment compatible with dissection (image B). Patient’s hypercoaguable, inflammatory and rheumatological markers were unremarkable. The patient was started on aspirin 81 mg daily and Plavix 75 mg daily for three weeks followed by aspirin monotherapy. Repeat CT angiogram 11 months later still showed right V1/V2 junction irregularity (image C). DSA performed one month later revealed right cervical vertebral artery web with mild stagnation of blood flow (image D). Patient had no recurrence of symptoms and was continued on aspirin. Conclusion Ischemic stroke is rare in young adults. According to recent studies, prevalence of stroke in young adults’ ranges from 10‐15% of entire population stroke burden. Our case describes a young patient with posterior circulation stroke caused by a vertebral artery web which was confirmed with DSA. Vertebral artery web has limited scientific documentation throughout the literature. A literature review performed by B.J.A. Pereira et al. demonstrated that only 7.3% of vessel webs were found in the vertebral artery, compared to 91.66% in the carotid artery (3). Because of this, a review of medical literature showed limited case reports on treatment and surgical options for vertebral webs causing posterior circulation stroke. Lenck et al. first reported 3 patients with vertebral webs diagnosed by DSA and having MRI show ischemic strokes in the vascular territory were treated with endovascular stenting and had no recurrence of an ischemic event (4). A literature review reported by Pereira demonstrated that out of 23 vessel webs, 13 were treated with supportive care (including antiplatelets or anticoagulation), eight were treated with angioplasty and stenting (which included the vertebral artery web case), and two were treated with surgery (3). In other literature, Lizhang et al (2019) diagnosed an incidental vertebral artery web on DSA for anterior circulation TIA and was treated successfully with DAPT therapy and atorvastatin 20 mg (5).

Abstract 054: Transradial Thrombectomy Using "Sheathless PV" Guide Catheter in Armenia: Three‐Year Institutional Experience in 103 Cases

Introduction Transradial access (TRA) in neuroendovascular procedures has gained popularity in recent years (1). It offers numerous advantages and stimulated development of long flexible large lumen guiding catheters as well as adoption of existing cost‐efficient alternatives used in cardiac and peripheral interventions (2,3). We report our three‐year experience using the Sheathless PV guide catheter (Asahi Intecc, Japan) in a consecutive series of acute stroke patients undergoing endovascular thrombectomy (ET) at a Comprehensive Stroke Center in Yerevan, Armenia. The interest in its use specifically for TRA stemmed from competitive price (∼ $100 per catheter vs ), hydrophilic coating of the outer shaft, as well as lack of femoral closure devices in the country. Methods We retrospectively identified all consecutive acute stroke patients who had undergone ET via TRA from a prospectively maintained institutional stroke database between June 2020 and June 2023. Data were collected on determinants of decision to proceed with TRA‐first approach, baseline patient imaging and clinical characteristics, location of the occlusion, puncture‐to‐reperfusion time (PT‐RT), conversion to transfemoral access (TFA), periprocedural complications, and procedural/clinical outcomes. Results were compared to patients who underwent TFA‐first ET over the same time period. The Mann‐Whitney U‐test was used to analyze the continuous variables and chi‐square test was used for categorical variables. Standardized TRA technique involved exchanging the puncture needle to a short 6Fr introducer first, then over a J‐wire, to a 90cm (0.090" ID/0.110" OD) Sheathless PV guide catheter over a dilator. The dilator was then removed, and a long JR4 diagnostic catheter was used to select cervical vessels over a 0.035 wire and advance the guide over in a triaxial fashion. Results A total of 538 patients underwent ET during the analyzed 3‐year period, of which access was either not recorded, or was other than TRA/TFA in 23 patients (excluded from analysis). Of the remaining 515 patients, 103 had TRA‐first (all using Sheathless PV guide catheter) and 412 had TFA‐first (various guide catheters). The decision to proceed with TRA was at the discretion of the operator and was influenced by presence of bovine arch on CTA (for left anterior occlusions), favorable angle between the right subclavian and the right common carotid arteries (for right anterior occlusions), dominant right vertebral artery or favorable angle of V1 origin (for posterior circulation occlusions). Of 103 TRA cases, 71 (68.9%) were in the right carotid circulation, 18 (17.5%) ‐ in the left carotid circulation, and 14 (13.6%) in posterior circulation. TRA‐>TFA conversion occurred in 5 patients (4.8%), TFA‐>TRA ‐ in 1 patient (0.24%) all of which were due to prohibitive anatomy, rather than guide catheter limitations. There were no significant differences in baseline patient characteristics between the TRA and TFA groups. Angiographic outcomes (TICI 2B or greater) were similar for TRA vs TFA (96.1% vs 93.9%, p=0.39), as were good clinical outcome (discharge mRS 0‐2) rates (58% vs 55.4%, p=0.63). There was a trend towards shorter PT‐RT with TRA (29.5 min vs 38.3 min) although it did not reach statistical significance (p=0.11). No access‐related complications were noted with TRA. Conclusion Transradial thrombectomy using Sheathless PV Guide catheter is safe, effective, and offers substantial cost‐savings and shorter procedural times with low rate of access conversions, similar to other reported TRA thrombectomy series. Randomized trials are needed to validate its rates of technical success and complications against other frequently‐used TRA guide catheters.

Abstract 076: 2023 Fusarium Meningitis Outbreak: Neuroendovascular Outcomes and Observations of the Angioinvasive Disease from South Texas

Introduction The Centers for Disease Control and Prevention (CDC) issued a health advisory in response to an outbreak of Fusarium meningitis from exposure to spinal anesthesia for cosmetic surgery performed in Mexico between Jan 1 to May 13, 2023. This paper outlines the neuroendovascular and neurosurgical observations and management of this outbreak at our Comprehensive Stroke Center with a focus on angio‐invasive disease. Methods A retrospective chart review was performed for fungal meningitis patients that presented between April and July 2023. Results There were a total of 12 patients who were found to have fungal meningitis, 11 of whom were included in the final analysis with angio‐invasive Fusarium solani. The mean age was 31.7 ± 7.15. 92% of patients were female. CT and MRI were initially normal in two‐thirds of patients. No cases demonstrated positive growth on fungal cultures. Only (1→3)‐β‐D‐Glucan assays were positive in all patients who were tested. After several patients in this series developed subarachnoid hemorrhage from a ruptured mycotic aneurysm, we proceeded to institute weekly cerebral angiography protocol. This detected moderate to severe vasospasm in 75%, and aneurysms in 58%, with the most common site being the basilar artery. The aneurysms were seen exclusively in the posterior circulation. The average size of aneurysms when first detected was 5.0 ± 3.8 mm. Patients with brain aneurysms were treated with flow diversion in 57% of cases, primary coiling was performed in 14%, and the remaining expired prior to treatment. 14% in our series actually developed another episode of subarachnoid hemorrhage after treatment from a new angiographically confirmed aneurysm. All patients who presented with subarachnoid hemorrhage from mycotic aneurysms have passed or withdrawn care. With regard to vasospasm treatment, 80% had treatment with intra‐arterial verapamil and 40% underwent mechanical angioplasty. We did not perform balloon angioplasty in any case due to concern for rupture of the weakened compromised vessel walls. Finally with regard to cerebrospinal fluid (CSF) diversion; 67% underwent ventriculostomy, and a minority were converted to ventriculoperitoneal shunts. All but one patient received dual antifungal therapy with Amphotericin B and Voriconazole, and 42% were started on every other day intrathecal Amphotericin B. Conclusion We have found that in patients with fusarium meningitis that weekly angiographic surveillance for aneurysms and vasospasm should be performed. Conventional angiography is preferred to computed tomography angiography due to the smaller size of aneurysms. Aneurysms should be primarily coiled prior before flow diversion is attempted, and vasospastic vessels may be mechanically dilated in the setting of vessel wall necrosis.

Abstract 164: Chronic Total Occlusion of the Bilateral Internal Carotid Arteries, Vertebral Arteries and Basilar Artery

Introduction Bilateral internal carotid arteries (ICAs), vertebral arteries (VAs), and basilar artery chronic total occlusion is an exceedingly rare condition. Possible underlying etiologies include atherosclerosis, Moyamoya disease, dissection, among others. Methods Here we describe a 58‐year‐old man with chronic total occlusion of the bilateral ICAs, VAs and basilar artery of unknown etiology. Results A 58‐year‐old man who is independent for ADLs/iADLs with a history of prior ischemic strokes (first stroke at 40 years old) with residual left‐sided weakness and dysarthria, hypertension, hyperlipidemia, prior blood clots (previously on warfarin), post‐stroke epilepsy, and never smoker presented as a code stroke to the emergency department after waking that morning with worsening of his residual left‐sided weakness and dysarthria. On arrival, blood pressure was 165/94 mmHg and blood glucose was 108 mg/dL. His NIHSS was 6. His neurologic exam was grossly similar to that documented 19 months ago. In the CT scanner, he developed tonic‐clonic movements of the left arm and leg, confusion, and emesis. Later, he stated he had missed several doses of his prescribed levetiracetam. Head CT and brain MRI revealed encephalomalacia in the brainstem and bilateral cerebellar and cerebral hemispheres. Brain MRI did not demonstrate any diffusion restriction changes. CTA showed chronic occlusion of both ICAs (proximal, distal, and terminus), M1s, VAs (V4 segment), and basilar artery. CTA also revealed that the brain parenchyma was being perfused by collaterals between the external carotid artery (ECA) branches, superficial temporal artery, and M2 branches bilaterally and the bilateral posterior circulation arteries were small and reformed through collaterals. CTP showed a core and penumbra volumes of 0 mL. His presentation was consistent with a seizure. He was admitted to the stroke service for work‐up of his abnormal brain vasculature. Catheter angiography confirmed the CTA results demonstrating occluded bilateral cervical and intracranial segments of the ICAs, collaterals from bilateral ECA branches supplying the intracranial circulation, right VA occlusion distal to the right PICA, and left VA occlusion distal to the V3 segment. Remaining work‐up including A1c, LDL, urine drug screen, EKG, transthoracic echocardiogram, and telemetry was unrevealing other than for an LDL of 152. Routine EEG showed moderate generalized showing. During hospitalization, his home amlodipine and losartan medications were discontinued with the goal of maintaining a blood pressure target of 140‐160 systolic indefinitely, to minimize the risk of hypoperfusion cerebrally. Give his robust collaterals, surgical treatment with revascularization was not pursued. His home aspirin and rosuvastatin 40 mg daily were continued and ezetimibe 10 mg daily was added. His home levetiracetam was increased from 500 to 750 mg twice daily given recent unprovoked seizures at home. He was discharged to an inpatient rehabilitation facility. Conclusion To our knowledge, this is the first case report to show chronic total occlusion of the bilateral ICAs, VAs, and basilar artery. Diagnosis of Moyamoya disease stage VI ("disappearance of the Moyamoya") was entertained but felt to be less likely given involvement of the proximal ICAs and posterior circulation. Other diagnostic consideration included atherosclerosis. Overall, the underlying etiology of his condition remained elusive.

Abstract 264: Enhancing Stroke Care: Neurology Residents' Clinical Prediction of Large Vessel Occlusions for Faster Endovascular Activation

Introduction Large vessel occlusions (LVO) account for approximately 15 to 30% of acute ischemic strokes, necessitating rapid clinical recognition to facilitate timely endovascular team activation and reduce door‐to‐reperfusion time for mechanical thrombectomy (MT). Existing clinical LVO scales, such as RACE, FASTED, and VAN, designed for utilization by Emergency Medical Services (EMS), lack reliability and have not been widely adopted for pre‐activation of endovascular teams. Typically, endovascular team activation occurs after LVO confirmation through neuroimaging, highlighting the need for improved methods to identify LVO during early assessments by neurologists. Methods A prospective observational study was conducted at University Hospital, involving all stroke codes activated by the Emergency Department (ED) or EMS. Neurology residents responding to the codes performed initial assessments, encompassing patient history, physical examination, and NIH Stroke Scale (NIHSS) evaluations. Based on the onset and severity of symptoms, presence of cortical signs, and NIHSS scores, patients were classified into four categories: A) probable LVO and stroke, B) possible LVO and stroke, C) not LVO but probable stroke, and D) probable stroke mimic. All assessments were completed before CT scanning. Results Over a ten‐month period, 159 stroke codes were evaluated by neurology residents. Among these, 27 patients were diagnosed with LVO, while 132 patients had no LVO. The neurology residents classified 18 patients into the probable stroke group, demonstrating a sensitivity of 48%, specificity of 96%, a positive predictive value (PPV) of 72%, and a negative predictive value (NPV) of 90%. Combining the probable and possible stroke groups, the residents identified 34 patients with a sensitivity of 74%, specificity of 89%, a PPV of 5%, and an NPV of 94%. Regrettably, seven patients with LVO were misclassified as either stroke mimics or non‐LVO strokes. Among these cases, five patients presented with low NIHSS scores, two had LVO in the posterior circulation, and one developed an in‐stent thrombus. Conclusion Our study revealed that neurology residents' ability to predict LVO was comparable to other LVO prediction scales in terms of sensitivity and specificity, but significantly improved in PPV. With a PPV exceeding 70%, the clinical prediction of LVO by neurology residents proves to be a valuable tool for activating the endovascular team promptly. This approach holds promise for enhancing stroke care in both the emergency department and pre‐hospital ambulance‐based settings. Nevertheless, larger studies are warranted to validate and further refine these findings. Implementing the neurology residents' clinical judgment in LVO identification can potentially optimize patient outcomes and treatment timelines in acute ischemic strokes.

Abstract 089: A Case of Complicated Dissection: Vertebral Artery Sacrifice for Recurrent Stroke Prevention

Introduction Posterior circulation strokes account for 20% of ischemic strokes (1). Optimal management for posterior circulation strokes has been studied less than for anterior circulation strokes (2). Endovascular parent vessel sacrifice is an established technique used to treat vascular pathologies. There is limited evidence for parent artery sacrifice for recurrent strokes and there is no current guideline for standard of care. Methods '‐ Results 51‐year‐old gentleman with history of tobacco use presented with left homonymous hemianopsia, onset 1.5 hours prior to arrival. CT brain showed no bleed and patient received IV tissue‐plasminogen activator (tPA). CT angiography (CTA) demonstrated occlusion of the right posterior cerebral artery (PCA) and dissection of the left vertebral artery (V2 segment) with distal reconstitution. He underwent emergent thrombectomy for right P2 thrombus with complete reperfusion TICI 3 (Thrombolysis in Cerebral Infarction Score). Less than 24 hours later, he developed a right homonymous hemianopsia, and was found to have a new occlusion of the left P1 segment of the left PCA. Emergent thrombectomy was performed with complete reperfusion (TICI3). MRI brain demonstrated bilateral PCA territory infarcts. Within 12 hours of the second thrombectomy, his neurological exam deteriorated, and interval imaging revealed a basilar trunk thrombus, for which he underwent a successful endovascular thrombectomy complete reperfusion (TICI3). His antiplatelet regimen was optimized with Aspirin. Heparin was considered as treatment but was not provided because of the hemorrhagic conversion of his ischemic strokes. Given the persistent recurrence of thromboemboli in the posterior circulation despite being on optimal medical management, and evidence of hemorrhagic conversion, a decision was made to perform endovascular coil embolization of the left vertebral artery V2 segment at the site of dissection. Angiographic imaging demonstrated antegrade blood flow through the dissection as the source of recurrent embolic strokes. Six Stryker Target coils were deployed spanning the region of dissection within the left V2 segment via a right radial access with the guide catheter in the right vertebral artery. Post coil embolization angiographic runs demonstrated complete occlusion of the left vertebral V2 segment at the region of dissection which was confirmed via a left vertebral injection from a left femoral arterial access. There was preservation of ascending cervical collaterals beyond the dissection with patency of the contralateral vertebral artery supplying the intracranial circulation. Following embolization, repeat imaging showed no new infarcts and no new or worsening hemorrhage. He was continued on Aspirin monotherapy. It is notable that though his neurological exam deteriorated during each recurrent thromboembolic event, his neurologic exam at the time of discharge significantly improved with NIHSS of 3. He is currently being followed at our neuroscience institute. Conclusion Cervical arterial dissections pose increased risk for ischemic strokes (3). Vertebral artery dissection accounts for approximately 2%, of which, 10‐25% occur in middle‐aged and younger patients (4). This is a case of a young patient that exemplifies a successful role for vertebral artery sacrifice with coil embolization to prevent recurrent thromboembolic posterior circulation strokes. However controlled studies are needed for safety and efficacy of these interventions.

Abstract 173: A Case Series of Basilar Tip Aneurysm Endovascular Treatment – The Barrow Neurological Institute Experience

Introduction Basilar‐tip aneurysm (BTA) is the most common aneurysm found in the posterior circulation, representing 5–8% of total intracranial aneurysms. Endovascular techniques are first‐line for treatment of the vast majority of posterior circulation artery aneurysms because of their deep location and the high mortality and morbidity associated with microsurgical clipping. Coil embolization (CE) is safer and more efficacious in the treatment of BTAs compared to open surgery but has increased rate of recanalization. Two adjunctive modifications of CE ‐ balloon remodeling techniques (BRT) and stent‐assisted coiling (SAC) ‐ have been utilized to facilitate occlusion of BTAs of variable anatomies/morphologies, sizes, and rupture status. We aimed to compare the clinical utility, safety and efficacy of these adjuvant therapies for treating BTAs. Methods A retrospective secondary analysis of a prospectively collected database at our institution was performed, including all patients with endovascularly treated basilar tip aneurysms database from January 1996 through January 2019 (n=121; CE=26; BRT=51; SAC=44). This project was approved by the local institutional review board. Patient data on demographics, aneurysmal characteristics and management, post‐operative outcomes, ICU management, and withdrawal of care were abstracted from the medical record of eligible patients. Univariate statistics used Welch’s two‐sample t‐test for continuous data and chi‐squared test for frequency‐based variables. Multivariate analysis used multivariate Poisson and Firth’s logistic regression. Results Aneurysms treated with CE were found to be smaller compared to BAC and SAC, with a median difference of 4 mm. For ruptured aneurysms, Adjuvant therapy (BAC or SAC) was used to treat larger dimension aneurysms compared to CE (p = 0.046). Adjusted for other factors, aneurysm dimension was an independent factor influencing recanalization or recurrence (OR = 1.16, p = 0.006), retreatment (OR = 1.165, p = 0.005), and obliteration (Raymond Roy Grade, continuous, β = 0.033, p = 0.043). Ruptured aneurysms were most frequently treated with CE (80.8%), followed by BAC (47.1%), and least frequently with SAC (6.8%) (p < 0.001). We also found an association with time of approval to retreatment. Stents approved by FDA after 2014 (used in 13 cases) had a greater rate of retreatment (46.2% vs. 10.7%). Adjusted for other factors, BAC had 3 times greater odds of recanalization or recurrence compared to SAC. CE demonstrated a 1.19‐month greater time to retreatment than BAC and a 1.89‐month longer time to retreatment than SAC. Overall, CE had a 1.28‐month greater time to retreatment than adjuvant therapy (SAC or BAC). Conclusion CE and its adjuvant therapies have similar safety profile but pose variable efficacy in terms of obliteration, recurrence, retreatment, and durability over time. This study represents one of the largest data sets on endovascular adjuvant therapy of BTAs and has the potential to inform clinical decision making when considering CE with BRT vs. SAC for BTA of specific size and morphology. In the future, inclusion of BTAs treated with WEB device and more novel flow divertor devices in this data set can further inform clinical decision making.

Flow diversion: a disruptive technology coming of age. Lessons learned and challenges for the future.

Intracranial aneurysm treatment has been revolutionized over the last decade with the development of flow diversion technology. The use of this technology has evolved rapidly and has proven that cerebrovascular disease treatment remains one of the forefront innovation areas in neurosurgery. The good results on the treatment of internal carotid artery aneurysms up to the communicating segment have motivated the use of flow diversion beyond the circle of Willis and in the posterior circulation. Further advances and innovations of flow-diverting devices are underway and intended to improve the safety and efficacy of this therapy. This review article provides a detailed discussion about the origin, mechanism of action, initial experience, complications, types of devices, and future perspectives of flow diversion technology.