Internal Carotid Artery Terminus Research Articles

Prevalence and Angiographic Outcomes of Rescue Intracranial Stenting in Large Vessel Occlusion Following Stroke Thrombectomy – STRATIS

BACKGROUND Large vessel occlusion secondary to underlying intracranial atherosclerotic disease (ICAD‐LVO) has an estimated prevalence of 7% to30%. There is a large variation in the use of intracranial rescue stenting in interventional practice. We aimed to characterize the frequency and characteristics of intracranial rescue stenting in a large cohort of endovascular therapy for stroke. METHODS The Systematic Evaluation of Patients Treated With Stroke Devices for Acute Ischemic Stroke (STRATIS) angiography core lab adjudicated the location of the occlusion, hyperdense vessel sign on initial imaging, the use of angioplasty and stenting, and imaging outcomes following endovascular therapy. Underlying cause of stroke was categorized into intracranial atherosclerosis, cardioembolic, and other subtypes. Statistical analyses examined the relationship between intracranial rescue stenting and imaging outcomes including intracranial hemorrhage, and arterial reperfusion using expanded Thrombolysis in Cerebral Infarction reperfusion score in patients with ICAD‐LVO. RESULTS Among 978 patients with LVO stroke undergoing endovascular therapy, 91 (9.3%) patients had ICAD‐LVO. Baseline hyperdense vessel sign was observed among 44 (62.7%) with ICAD versus 178 (68.2%) with cardioembolic LVO ( P = 0.4). Final successful reperfusion (expanded Thrombolysis in Cerebral Infarction 2b50 or more) was significantly lower among ICAD‐LVO as compared with cardioembolic‐LVO (74.2% versus 87.5%; P = 0.007). Intracranial rescue stenting was used among 14/665 (2.1%) of patients with LVO (5 ICA terminus, 7 M1 middle cerebral artery, 1 M2 middle cerebral artery, 1 proximal basilar artery). Among 14 intracranial rescue stenting cases, 5/70 (7.1%) belonged to the ICAD group, 3/261 (1.1%) cardioembolic group, and 6/334 (1.8%) in other or undetermined group. Successful reperfusion following rescue stenting was achieved in all cases with ICAD‐LVO. Among ICAD‐LVO, the rate of 24 hours symptomatic intracranial hemorrhage was 0% with acute intracranial stenting versus 7.7% in the nonstenting subgroup. CONCLUSION In STRATIS, nearly 1 of every 11 thrombectomies were performed in patients with underlying ICAD, among whom 7.1% underwent rescue intracranial stenting concomitant with thrombectomy. Acute intracranial stenting as rescue therapy in ICAD‐LVO was associated with favorable angiographic outcomes and low symptomatic hemorrhage rates.

Prevalence and Angiographic Outcomes of Rescue Intracranial Stenting in Large Vessel Occlusion Following Stroke Thrombectomy – STRATIS

BACKGROUND Large vessel occlusion secondary to underlying intracranial atherosclerotic disease (ICAD‐LVO) has an estimated prevalence of 7% to30%. There is a large variation in the use of intracranial rescue stenting in interventional practice. We aimed to characterize the frequency and characteristics of intracranial rescue stenting in a large cohort of endovascular therapy for stroke. METHODS The Systematic Evaluation of Patients Treated With Stroke Devices for Acute Ischemic Stroke (STRATIS) angiography core lab adjudicated the location of the occlusion, hyperdense vessel sign on initial imaging, the use of angioplasty and stenting, and imaging outcomes following endovascular therapy. Underlying cause of stroke was categorized into intracranial atherosclerosis, cardioembolic, and other subtypes. Statistical analyses examined the relationship between intracranial rescue stenting and imaging outcomes including intracranial hemorrhage, and arterial reperfusion using expanded Thrombolysis in Cerebral Infarction reperfusion score in patients with ICAD‐LVO. RESULTS Among 978 patients with LVO stroke undergoing endovascular therapy, 91 (9.3%) patients had ICAD‐LVO. Baseline hyperdense vessel sign was observed among 44 (62.7%) with ICAD versus 178 (68.2%) with cardioembolic LVO ( P = 0.4). Final successful reperfusion (expanded Thrombolysis in Cerebral Infarction 2b50 or more) was significantly lower among ICAD‐LVO as compared with cardioembolic‐LVO (74.2% versus 87.5%; P = 0.007). Intracranial rescue stenting was used among 14/665 (2.1%) of patients with LVO (5 ICA terminus, 7 M1 middle cerebral artery, 1 M2 middle cerebral artery, 1 proximal basilar artery). Among 14 intracranial rescue stenting cases, 5/70 (7.1%) belonged to the ICAD group, 3/261 (1.1%) cardioembolic group, and 6/334 (1.8%) in other or undetermined group. Successful reperfusion following rescue stenting was achieved in all cases with ICAD‐LVO. Among ICAD‐LVO, the rate of 24 hours symptomatic intracranial hemorrhage was 0% with acute intracranial stenting versus 7.7% in the nonstenting subgroup. CONCLUSION In STRATIS, nearly 1 of every 11 thrombectomies were performed in patients with underlying ICAD, among whom 7.1% underwent rescue intracranial stenting concomitant with thrombectomy. Acute intracranial stenting as rescue therapy in ICAD‐LVO was associated with favorable angiographic outcomes and low symptomatic hemorrhage rates.

Validation of the transcranial Doppler rescue criteria for mechanical thrombectomy.

Transcranial Doppler (TCD) identifies acute stroke patients with arterial occlusion where treatment may not effectively open the blocked vessel. This study aimed to examine the clinical utility and prognostic value of TCD flow findings in patients enrolled in a multicenter prospective study (CLOTBUST-PRO). Patients enrolled with intracranial occlusion on computed tomography angiography (CTA) who underwent urgent TCD evaluation before intravenous thrombolysis was included in this analysis. TCD findings were assessed using the mean flow velocity (MFV) ratio, comparing the reciprocal ratios of the middle cerebral artery (MCA) depths bilaterally (affected MCA-to-contralateral MCA MFV [aMCA/cMCA MFV ratio]). A total of 222 patients with intracranial occlusion on CTA were included in the study (mean age: 64±14years, 62% men). Eighty-eight patients had M1 MCA occlusions; baseline mean National Institutes of Health Stroke Scale (NIHSS) score was 16, and a 24-hour mean NIHSS score was 10 points. An aMCA/cMCA MFV ratio of <.6 had a sensitivity of 99%, specificity of 16%, positive predictive value (PV) of 60%, and negative PV of 94% for identifying large vessel occlusion (LVO) including M1 MCA, terminal internal carotid artery, or tandem ICA/MCA. Thrombolysis in Brain Ischemia scale, with (grade ≥1) compared to without flow (grade 0), showed a sensitivity of 17.1%, specificity of 86.9%, positive PV of 62%, and negative PV of 46% for identifying LVO. TCD is a valuable modality for evaluating arterial circulation in acute ischemic stroke patients, demonstrating significant potential as a screening tool for intravenous/intra-arterial lysis protocols.

Thrombectomy using Zoom Reperfusion System in pediatric acute ischemic strokes: Case series and literature review.

Zoom reperfusion system (Imperative Care, CA) has proven to be promising for use in adult mechanical thrombectomies (MTs) but has not been described in pediatrics. We present two cases of a 14-year-old with acute right middle cerebral artery (MCA) syndrome and a 10-year old with acute left MCA syndrome who underwent MT using Zoom Reperfusion System safely with TICI 2B and TICI 3 recanalization, respectively. Case report and literature review. A 14-year-old healthy boy with right supraclinoid internal carotid artery (ICA) occlusion (case 1) and a 10-year-old boy with left hypoplastic heart syndrome and left ICA terminus occlusion (case 2) were taken for MT after receiving alteplase at our institution. Through femoral access, an 8-French sheath was introduced into the right femoral artery through which a Zoom 88 catheter was introduced and parked at the right petrous ICA segment in case 1 and left ophthalmic ICA segment in case 2. Angiogram demonstrated complete ICA occlusion just past the ophthalmic artery origin in case 1 and at the ICA terminus in case 2. Zoom system (88 and 71) was then navigated to the face of clot with vacuum manifold engaged with the clot. TICI 2B (with the help of Trevo stent retriever [Stryker]) and TICI 3 recanalization were achieved in cases 1 and 2, respectively. The use of Zoom reperfusion system could potentially be feasible for use in pediatric age group. Larger pediatric patient population is needed to establish its safety.

Thromboembolic Events After the Coverage of Anterior Cerebral Artery with Flow Diversion: A Single Institution Series and Systematic Review

Advances in the use of flow diversion (FD) now extend to bifurcation aneurysms; herein, we compare thromboembolic events in patients with ICA aneurysms treated with and without exclusion of the ACA. Retrospective analysis of aneurysms in the terminal ICA treated with FD from 2013 to 2023 at a single-center. Procedures were classified according to the coverage at the origin of the ACA, and compared through bivariate-analysis. A review was also carried on PubMed, Web of Science, and EMBASE until April 2024, adhering to the PRISMA reporting guidelines. Ninety-five patients harboring 113 aneurysms treated in 102 procedures were evaluated. Fifty-eight were treated covering the ACA origin. Dual antiplatelet regimens included aspirin-clopidogrel (50%), aspirin-ticagrelor (44.1%), and aspirin-prasugrel (4.9%). Thromboembolic events occurred in six patients (5.9%), presenting with large vessel occlusion of the ICA, but without reaching statistical difference in the two treated cohorts (p=0.46). At a median clinical follow-up of 5.95 months, there were no differences in the functional outcomes in the two groups (p=0.22). Contralateral angiographic runs post-treatment after covering the ACA origin demonstrated increase in the A1 (median: 0.45mm; IQR=0.4-1.2) and ICA diameter (median: 0.55mm; IQR=0.1-1.2). After pooling data from literature and our cohort, complete side branch occlusion after the coverage of ACA was seen in 25% of branches (95%CI=0.16-0.36), and thromboembolic events were observed after 3% (95%CI=0.01-0.04) of procedures. Thromboembolic events can occur in distal ICA aneurysms treated with FD, but no significant association was seen with covering the ACA origin.

Quantitative Analysis of the Supraorbital, Transorbital Microscopic, and Transorbital Neuroendoscopic Approaches to the Anterior Skull Base and Paramedian Vasculature

Abstract Objectives Our objective was to compare transorbital neuroendoscopic surgery (TONES) with open craniotomy and analyze the effect of visualization technology on surgical freedom. Design Anatomic dissections included supraorbital craniotomy (SOC), transorbital microscopic surgery (TMS), and TONES. Setting The study was performed in a neurosurgical anatomy laboratory. Participants Neurosurgeons dissecting cadaveric specimens were included in the study. Main Outcome Measures Morphometric analysis of cranial nerve (CN) accessible lengths, frontal lobe base area of exposure, and craniocaudal and mediolateral angle of attack and volume of surgical freedom (VSF) of the paraclinoid internal carotid artery (ICA), terminal ICA, and anterior communicating artery (ACoA). Results The mean (standard deviation [SD]) frontal lobe base parenchymal exposures for SOC, TMS, and TONES were 955.4 (261.7) mm2, 846.2 (249.9) mm2, and 944.7 (158.8) mm2, respectively. Access to distal vasculature was hindered when using TMS and TONES. Multivariate analysis estimated that accessing the paraclinoid ICA with SOC would provide an 11.2- mm3 increase in normalized volume (NV) compared with transorbital corridors (p &lt; 0.001). There was no difference between the three approaches for ipsilateral terminal ICA VSF (p = 0.71). Compared with TONES, TMS provided more access to the terminal ICA. For the ACoA, SOC produced the greatest access corridor maneuverability (mean [SD] NV: 15.6 [5.6] mm3 for SOC, 13.7 [4.4] mm3 for TMS, and 7.2 [3.5] mm3 for TONES; p = 0.01). Conclusion SOC provides superior surgical freedom for targets that require more lateral maneuverability, but the transorbital corridor is an option for accessing the frontal lobe base and terminal ICA. Instrument freedom differs quantifiably between the microscope and endoscope. A combined visualization strategy is optimal for the transorbital corridor.

Intensity Score of Vessel Wall Contrast Enhancement in MRI Allows Prediction of Disease Progression in Moyamoya Angiopathy.

The underlying pathophysiological cause of moyamoya angiopathy (MMA) is still unclear. High-resolution vessel wall imaging has become a useful tool. The aim was to study vessel wall contrast-enhancement (VW-CE) as an imaging marker to predict disease progression in MMA. Patients with MMA, who had undergone serial contrast-enhanced high-resolution MRI with concomitant and follow-up digital subtraction angiography, were analyzed retrospectively. VW-CE was semiquantified by measurement of the signal intensity of the vessel wall in in contrast-enhanced high-resolution MRI. A comparative quotient with the contrast-intensity of the pituitary stalk was calculated and graded accordingly from grade 1 to 5. VW-CE status was correlated with disease status, stroke, cerebrovascular reactivity in CO2-triggered blood-oxygen level-dependent MRI, angiographic disease progression, revascularization surgery, and follow-up imaging. Forty eight patients met the inclusion criteria. N = 56 MRI and digital subtraction angiography time-intervals were evaluated for 12 vessel sections per hemisphere each (N = 1344). N = 38 (79%) patients showed VW-CE and N = 10 (21%) did not. VW-CE was only observed in the terminal internal carotid artery and the proximal circle of Willis (N = 96/1344). Notably, patients with VW-CE significantly more often presented with acute infarction in the concomitant MRI. The incidence of angiographically proven disease progression was significantly associated with the incidence of VW-CE, and time to disease progression was earlier in higher grades of VW-CE compared with lower grades. VW-CE is a semiquantifiable marker for disease activity in patients with MMA and associated with disease progression and increased risk of stroke. VW-CE analysis can be routinely performed in patients with MMA to estimate the risk for disease progression and stroke.

Vessel wall imaging in the diagnosis of antiphospholipid syndrome presenting as Moyamoya syndrome-A case report.

Objectives: We describe a case of anti-phospholipid syndrome (APLS) vasculopathy presenting with Moyamoya syndrome (MMS) and show the associated intracranial vessel wall MRI (VWI) findings. Methods: A 37-year-old-woman presented with acute onset dizziness and left-sided weakness. Neurologic exam revealed a left facial droop and left hemiparesis. She underwent a comprehensive laboratory work-up for stroke. Neuroimaging included a CT head, CT angiogram, VWI, and digital subtraction angiography. Results: Work-up revealed a triple-positive APLS antibody profile. CT of the head showed an acute right basal ganglia infarction and right frontal subarachnoid hemorrhage. CT angiogram revealed severe stenosis of the right internal carotid artery terminus in a Moyamoya pattern. Intracranial VWI showed long-segment concentric vessel wall thickening and homogeneous vessel wall enhancement and T2-hyperintense wall edema of the stenotic right ICA terminus, M1 middle cerebral artery, and A1 anterior cerebral artery. She was treated with long-term anticoagulation with warfarin and a right superficial temporal artery to middle cerebral artery bypass. Discussion: We present intracranial VWI features of vessel wall pathology in a patient with primary APLS presenting with MMS.

Classification and hemodynamic characteristics of delayed intracerebral hemorrhage following stent-assisted coil embolism in unruptured intracranial aneurysms.

Stent-assisted coil (SAC) embolization is a commonly used endovascular treatment for unruptured intracranial aneurysms (UIAs) but can be associated with symptomatic delayed intracerebral hemorrhage (DICH). Our study aimed to investigate the hemodynamic risk factors contributing to DICH following SAC embolization and to establish a classification for DICH predicated on hemodynamic profiles. This retrospective study included patients with UIAs located in the internal carotid artery (ICA) treated with SAC embolization at our institution from January 2021 to January 2022. We focused on eight patients who developed postoperative DICH and matched them with sixteen control patients without DICH. Using computational fluid dynamics, we evaluated the hemodynamic changes in distal arteries [terminal ICA, the anterior cerebral artery (ACA), and middle cerebral artery (MCA)] pre-and post-embolization. We distinguished DICH-related arteries from unrelated ones (ACA or MCA) and compared their hemodynamic alterations. An imbalance index, quantifying the differential in flow velocity changes between ACA and MCA post-embolization, was employed to gauge the flow distribution in distal arteries was used to assess distal arterial flow distribution. We identified two types of DICH based on postoperative flow alterations. In type 1, there was a significant lower in the mean velocity increase rate of the DICH-related artery compared to the unrelated artery (-47.25 ± 3.88% vs. 42.85 ± 3.03%; p < 0.001), whereas, in type 2, there was a notable higher (110.58 ± 9.42% vs. 17.60 ± 4.69%; p < 0.001). Both DICH types demonstrated a higher imbalance index than the control group, suggesting an association between altered distal arterial blood flow distribution and DICH occurrence. DICH in SAC-treated UIAs can manifest as either a lower (type 1) or higher (type 2) in the rate of velocity in DICH-related arteries. An imbalance in distal arterial blood flow distribution appears to be a significant factor in DICH development.

Abstract WP2: Natural History of Large Vessel Occlusion Patients Presenting With Minor Stroke Symptoms

Background: Acute ischemic stroke is a leading cause of mortality and disability in the US, with 50% of patients with minor stroke symptoms (MSS). Large vessel occlusion (LVO) is found in 10% of MSS cases and predicts poor neurological outcomes. However, treatment strategies for MSS-LVO lack consensus, and a deeper understanding of the natural history of MSS-LVO is needed. Methods: We screened all patients presenting to a large stroke network, from May 2017 to August 2023, for intracranial anterior circulation LVO and MSS (NIHSS %lt 6). Descriptive statistics were applied to demographic, clinical, radiographic, and neurological outcomes data, including early neurological deterioration (END) (NIHSS gain 3+). Results: Ninety patients participated in the study, averaging 64.5 years old, with 58.8% male, 48.8% white, 22.2% black, and 16.2% Hispanic. Comorbidities included diabetes (23%), hypertension (67.7%), atrial fibrillation (22%), hyperlipidemia (53%), and smoking (40%). Patients arrived with mean 7 hours (SE 1.6) from LKW, and a mean NIHSS 3.95 (SE 0.40). The majority of patients had baseline mRS of 0-2 (92.6%). Occlusion sites included M1 (38.9%), M2 (40%), and ICA terminus (2.2%). The mean ASPECTS score was 9.4 (SE 0.13). Immediate thrombolytic treatment was delivered to 34% of patients. Out of 90 patients, 31 (34%) suffered END, with mean NIHSS at END of 9.17 (SE 0.85), necessitating rescue endovascular thrombectomy (EVT). Collateral vessel failure caused 87.1% of END cases, clot migration 9.7%, and additional strokes 3.2%. Of the 31 EVT cases, 29 (93%) achieved TICI 2b-3, averaging 3.1 (SE 0.35) passes. ICH occurred in 5 patients; 2 had undergone EVT, although none were symptomatic. At 24 hours and 5 days from presentation, the mean NIHSS were 3.15 and 2.86 respectively, worse in END patients (6.16 vs 1.55, p=0.00, and 6.28 vs 1.14, p=0.00). After 30 days, only 66% of END patients had mRS of 0-2 compared to 84% of non-END patients (p=0.02). Similarly, at 90 days, only 65% of END patients, versus 86% of non-END patients, had mRS of 0-2 (p=0.02). Conclusion: The study details the natural history of MSS-LVO, showing a prominent incidence of EVT-requiring END due to collateral failure. Future research should identify high-risk END patients for tailored treatment.

Abstract WP234: Intracranial Vasculopathy Patterns of RNF213 R4810K Carriers: Does Anatomical Difference Make a Clinical Difference?

Introduction: The 2021 revised diagnostic criteria of Moyamoya’s disease (MMD) of Japan more emphasize terminal ICA involvement than 2012 version. Accordingly, there is still ambiguity about whether MCA steno-occlusion with intact ICA qualifies as MMD. Also, basal collateral is mandated in both versions, while its specificity and sensitivity for MMD remain uncertain. Although the discovery of RNF 213 R4810K variant gave hope for further insight into MMD, its diagnostic role is limited by scarce data on associated vasculopathy pattern. Methods: Patients with intracranial vasculopathy tested for RNF213 genotype between September 2017 and 2022 and positive for R4810K were included. They were classified by two anatomical features of vasculopathy in the latest angiographic image: 1) steno-occlusive degree of ICA and MCA, 2) laterality. The resulting classification composes 3 main and 6 subgroups: A) No involvement. B) MCA involvement and intact ICA, bilaterally (B1) or unilaterally (B2). C) ICA involvement, bilaterally (C1), unilaterally (C2), or unilaterally with contralateral MCA involvement (C3). Their demographic and clinical factors were compared, and fulfillment for MMD by 2012 and 2021 criteria was assessed. Results: Among 240 eligible patients, 84 (35.9%) and 33 (14.1%) did not meet 2021 and 2012 criteria. Notably, though group B showed high basal collateral prevalence of over 80%, all (100%) and 25 (36.8%) of them did not fulfill 2021 and 2012 criteria by ICA and MCA parameters. This group showed no significant contrast in demographic, conventional stroke risk factors and hemorrhagic or ischemic stroke prevalence from those with ICA involvement. Conclusions: Despite their clinical and demographic similarities, a notable number of RNF213 R4810K carriers do not meet MMD criteria due to anatomical features, mainly when ICA involvement is absent. Revising the criteria of MMD to incorporate RNF213 R4810K positivity should be considered to address its weakness.

A "Radial Ready" Tricoaxial Setup for Anterior Circulation Mechanical Thrombectomy: Technical Aspects and Preliminary Results.

Mechanical thrombectomy (MT) is the standard of care for acute ischemic stroke (AIS) due to large vessel occlusion (LVO). The choice of a transradial approach (TRA) for anterior circulation LVOs is still debatable; the use of a specific tricoaxial system could help mitigate numerous issues related to transradial MT. From November 2022 to November 2023, 22 patients underwent TRA-MT for anterior circulation LVOs, both as first-line and rescue from transfemoral approach (TFA) failure, with the same triaxial setup consisting of a 7F introducer sheath, 7F guide catheter, and aspiration catheters ranging from 5.5F to 5F in relation to the occlusion site. Choice of thrombectomy technique was at operator discretion. Patients' demographic data, clinical presentation, treatment details, complications, rate of crossover to TFA, successful revascularization (modified thrombolysis in cerebral infarction [mTICI] score ≥2b), and good clinical outcome at 3 months (modified Rankin scale [mRS] 0-2) were reported. Of 20 patients selected, 10 (50%) had occlusion of M1 segment of middle cerebral artery (MCA), 6 (30%) of internal carotid artery (ICA) terminus, and 4 (20%) with M2 MCA occlusions; 12/20 (60%) were right-sided occlusions and 8/20 (40%) were left-sided. The mean National Institutes of Health Stroke Scale score was 9.25 at admission. Successful revascularization to mTICI 2b-3 was achieved in 18/20 patients (90%). Intracranial complications were reported in 2 (10%) patients. Rate of radial artery occlusion at 24 hours was 10,6%; no access-site haemorrhagic complications were reported. Symptomatic intracranial hemorrhage occurred in 2 (10%) patients. mRS score 0-2 at 3 months was 50%. The high technical effectiveness and good safety profile of this specific tricoaxial setup for TRA-MT in AIS, even for large proximal LVOs, could constitute a viable alternative to TFA-MT in selected cases.

Continuous direct intraarterial treatment of meningitis-induced vasospasm in a pediatric patient: illustrative case.

Bacterial meningitis-induced ischemic stroke continues to cause significant long-term complications in pediatric patients. The authors present a case of severe right internal carotid artery terminus and M1 segment vasospasm in a 9-year-old with an infected cholesteatoma, which was refractory to multiple intraarterial treatments with verapamil and milrinone. This is the first report of continuous intraarterial antispasmodic treatment in a pediatric patient as well as the first report of continuous treatment in an awake and extubated patient. Arterial narrowing was successfully treated by continuous direct intraarterial administration of both a calcium channel blocker (verapamil) and a phosphodiesterase-3 inhibitor (milrinone). The patient recovered remarkably well and was discharged home with no neurological deficit (National Institutes of Health Stroke Scale score 0) and ambulatory without assistance after 22 days. The authors report a promising outcome of this technique performed in a pediatric patient. This represents a novel treatment option for the prevention of stroke in pediatric bacterial meningitis. Continuous, direct intraarterial administration of antispasmodic medications can successfully prevent long-term neurological deficit in pediatric meningitis-associated vasospasm. The described method has the potential to significantly improve outcomes in severe pediatric meningitis-associated vasospasm.

Successful mechanical thrombectomy for terminal ICA bullet embolism: A case report

Bullet embolism after high velocity penetrating trauma is a rare event that can have devastating and wide-ranging effects distant from the original site of injury. A 29-year-old presented with multiple gunshot wounds to the chest, back, abdomen, and lower extremities but no penetrating head injury. After proper resuscitation, the patient was noted to have left-sided hemiparesis and computed tomography angiography of the head showed a bullet fragment that had traveled to the right M1 segment of the middle cerebral artery resulting in occlusion of the vessel. Mechanical thrombectomy was performed in an attempt to remove the bullet fragment but this was unsuccessful as the fragment was firmly lodged in the blood vessel. Aspiration of clot distal to the fragment was then performed in hopes of preventing a large volume ischemic event which was angiographically successful resulting in TICI 2c revascularization. This case demonstrates that thrombectomy can be safely and successfully performed distal to a lodged foreign body.

Transcranial Doppler ultrasound velocities in a population of unstudied African children with sickle cell anemia.

The greatest burden of sickle cell anemia (SCA) globally occurs in sub-Saharan Africa, where significant morbidity and mortality occur secondary to SCA-induced vasculopathy and stroke. Transcranial Doppler ultrasound (TCD) can grade the severity of vasculopathy, with disease modifying therapy resulting in stroke reduction in high-risk children. However, TCD utilization for vasculopathy detection in African children with SCA remains understudied. The objective was to perform a prospective, observational study of TCD findings in a cohort of children with SCA from the Democratic Republic of the Congo, Zambia, and Malawi. A total of 770 children aged 2-17 years without prior stroke underwent screening TCD. A study was scored as low risk when the time-averaged maximum of the mean (TAMMX) in the middle cerebral artery or terminal internal carotid artery was <170cm/s but >50cm/s, conditional risk when 170-200cm/s, and high risk when>200cm/s. Low-risk studies were identified in 604 children (78%), conditional risk in 129 children (17%), and high risk in three children (0.4%). Additionally, 34 (4%) were scored as having an unknown risk study (TAMMX<50cm/s). Over the course of 15 months of follow-up, 17 children (2.2%) developed new neurologic symptoms (six with low-risk studies, seven with conditional risk, and four with unknown risk). African children with SCA in this cohort had a low rate of high-risk TCD screening results, even in those who developed new neurologic symptoms. Stroke in this population may be multifactorial with vasculopathy representing only one determinant. The development of a sensitive stroke prediction bundle incorporating relevant elements may help to guide preventative therapies in high-risk children.

Abstract 110: Autoangiogenesis Secondary to Chronic Cocaine Use Mimicking Moya‐Moya

Introduction We present the case of a young male presenting with syncope who was found to have incidental hypodensities on computed tomography (CT) of his head, with magnetic resonance imaging (MRI) concerning for Moya‐Moya related occlusion of the right internal carotid artery, but with digital subtraction angiography (DSA) showing extensive autoangiogenesis and collateralization from all other intracranial vascular territories, without Moya‐Moya related changes. This presumably developed as reactive changes to severe chronic cocaine use. Methods We present a case from a tertiary care center in the borough of Manhattan, New York City, USA. All information is deidentified and exempt from IRB approval. Results A 36‐year‐old man with history significant for asthma, active smoker status, and active cocaine use, presented for loss of consciousness. The patient reported 3 days of upper respiratory symptoms and decreased oral intake with subsequent loss of consciousness immediately preceded by lightheadedness and nausea, and without any post‐event confusion, lacerations, or incontinence. Neurologic history is significant for right upper extremity weakness from 9/2022‐12/2022 that self‐resolved and was believed to be a peripheral nerve pathology. Admission exam without focal deficits. Admission CT of his head showed multifocal confluent hypodensities in the subcortical right frontal lobe. CT Angiogram of head and neck showed severe narrowing at right Internal Carotid Artery (ICA) terminus and right M1 segment with lenticulostriate arterial collateralization, severe bilateral A1 stenosis with distal Anterior Cerebral Artery (ACA) flow suggestive of chronic collateralization, and significant right Posterior Cerebral Artery (PCA) collateralization. Given concern for Moya‐Moya disease, MRI of the brain was obtained and despite no acute infarct, MRI was significant for multifocal white matter T2/FLAIR hyperintensities with the largest in the right frontal lobe. The patient subsequently underwent digital subtraction angiography (DSA) to assess collaterals and stratify for possible need for future encephaloduroarteriosynangiosis (EDAS). DSA showed significant auto‐angiogenesis between numerous vascular territories, including recruitment of right Posterior Cerebral Artery and External Carotid Artery branches to perfuse the territory of the severe right ICA terminus steno‐occlusive disease. With minimal anterograde flow into the right Anterior Choroidal Artery and none to the right Middle Cerebral Artery (MCA), the characteristic Moya‐Moya appearance was not appreciated on DSA given minimal anigogenesis around the right ICA occlusion site. Rather, distal perfusion of the R ICA territory was dependent on collaterals from the right PCA, right ACA via the Anterior Communicating Artery, angiogenesis between the right Anterior Falcine Artery and R ACA, and angiogenesis between the right MCA and ACA/MCA cortical branches. These proliferative changes involved all cranial vascular territories, including those without steno‐occlusive disease. Conclusion Acute cocaine use is associated with increased risk of acute ischemic stroke[1], due in part to its sympathomimetic effects causing vasospasm and to its arrhythmic properties[2]. Neuroadaptation after chronic cocaine use is less well understood though rat models suggest that as cerebral ischemia develops from chronic cocaine use, the HIF‐VEGF pathway is activated to promote angiogenesis to restore local blood flow[3]. We present this case as evidence of a similar angiogenic physiologic response in humans to minimize the microvascular ischemic injury from chronic cocaine use.

Abstract 198: Case Report: Thrombectomy using Zoom Reperfusion System In Pediatric Acute Ischemic Strokes

Introduction Zoom reperfusion system (Imperative Care, CA) has proven to be promising for use in mechanical thrombectomies in adults but has not been described in pediatrics to our knowledge. We present two cases of a 14‐year‐old boy with acute right middle cerebral artery (MCA) syndrome and a 10‐year‐old boy with acute left MCA syndrome who underwent mechanical thrombectomy using Zoom Reperfusion System safely with TICI 2B and 3 recanalization respectively. Methods Case report and review of literature Results Case 1: 14‐year‐old previously healthy boy presented to our facility for acute right MCA syndrome secondary to right supraclinoid internal carotid artery (ICA) occlusion. After receiving alteplase, patient was taken for mechanical thrombectomy. After femoral access was obtained, an 8‐French sheath was introduced into the right femoral artery through which a Zoom 88 catheter and 5‐French BERN catheter (Terumo) were coaxially advanced over a Terumo Glidewire into the right common carotid artery. Under roadmap guidance, the Zoom 88 catheter was parked at the lacerum ICA segment with BERN catheter and Glidewire then removed. Angiogram demonstrated complete occlusion of the ICA just past the origin of the ophthalmic artery. Via Zoom 88 catheter, a Zoom 71 catheter was then navigated to the face of clot over a velocity microcatheter (Penumbra) and synchro 2 wire system (Stryker) which was then removed. The vacuum manifold was then attached to Zoom 71 catheter and allowed to engage with the clot for 3 minutes prior to withdrawal into the Zoom 88 catheter. TICI 2B recanalization was achieved with sub‐occlusive thrombus within the proximal M1 segment. Retrieval of the sub‐occlusive thrombus in the M1 segment was performed with TREVO stentriever (Stryker). Procedure was complicated by vasospasm in the A1 and M2 segments which resolved with milrinone and verapamil infused through the Zoom 88 catheter. Case 2: 10‐year‐old with left hypoplastic heart syndrome presented to our facility for acute left MCA syndrome due to left ICA terminus occlusion. Mechanical thrombectomy was performed after receiving alteplase. Femoral artery access was obtained with a 8‐French sheath, through which Zoom 88 catheter and 5‐French select catheter (Penumbra) were advanced over Terumo Glidewire into the left common carotid artery. Under roadmap guidance, the Zoom 88 catheter was parked at the ophthalmic segment of ICA with select catheter and Glidewire then removed. Angiogram demonstrated complete occlusion at the ICA terminus. Zoom 71 catheter was introduced through Zoom 88 catheter and navigated to the face of clot at the ICA terminus over velocity microcatheter (Penumbra) and synchro wire system (Stryker) which was then removed. Zoom 71 was then attached to a vacuum manifold to engage with the clot for 90 seconds. TICI 2A recanalization after first pass was achieved with flow restoration in anterior cerebral artery but none in the MCA.TICI 3 recanalization was achieved after second pass. Conclusion The use of Zoom reperfusion system potentially proves to be safe for use in the pediatric age group with good recanalization results and no intraoperative or postoperative complications.

Abstract 188: Rescue Left Middle Cerebral Artery Stenting With Xience Skypoint Everolimus‐Eluting Stent: Technical Report

Introduction Drug‐eluting stent (DES) use in symptomatic intracranial atherosclerosis disease (ICAD) has been described in the literature using different guiding and distal access catheters. We describe a case of deployment of a Xience Skypoint everolimus‐eluting stent (EES) (Abbott Vascular, Abbott Park, Illinois) into a symptomatic stenosed left M1 segment using Armadillo catheter (Q'Apel, Fremont, CA) with a successful result. Methods Case report and review of literature Results 67‐year‐old woman with type II diabetes mellitus, hypertension, hyperlipidemia, and recent admission for transient ischemic attack (resolving right hemiparesis and mild dysnomia in the setting of severe left M1 segment stenosis with discharge on Aspirin, Clopidogrel and Atorvastatin), presented with recurrence of symptoms, and MRI brain showing left basal ganglia acute infarction. No tPA was given low NIHSS and resolution of symptoms. Patient’s aphasia and hemiparesis worsened with segmental hypoperfusion which resolved by maintaining high blood pressures with norepinephrine drip. Decision was made to deploy a drug eluting stent into the stenosed M1 segment. Through femoral access, a 7F long destination sheath was inserted to the left common carotid origin. A 7F Armadillo catheter was then inserted into the left internal carotid artery (ICA) terminus. ASAHI Prowater coronary guidewire was inserted over which Xience Skypoint EES deployment was attempted but was unsuccessful given difficulty traversing the ICA ophthalmic segment. Ultimately, Armadillo catheter was advanced over a Phenom catheter (Medtronic) with good access into the distal M1 segment. The Phenom intermediate catheter was then removed, and the 2.25 mm x 12 mm stent was introduced through the Prowater guidewire into the segment and inflated to a pressure of 8 atm, with restoration of blood flow. Postoperatively, SBP was lowered to prevent reperfusion injury. Patient’s exam stabilized with mild dysnomia and right hemiparesis without any elevated blood pressure requirements. At 5‐months follow‐up, patient’s exam was non‐focal with NIHSS 0 and repeat DSA showed no evidence of stent occlusion and patent M1 segment. Conclusion Xience Skypoint EES can be successful in treating symptomatic MCA stenosis refractory to maximal medical therapy with good long term results.

Abstract 196: Navigation Orientation of the Angled Tip of the Zoom 71 catheter around the Carotid Siphon

Introduction Aspiration thrombectomy has been one of the mainstays of treatment in stroke interventions. The Zoom71 (Z71) aspiration catheter is unique with its angled tip. This study describes the orientation of the angled tip as its navigated around the carotid siphon and its association with trackability. Methods Prospectively collected cases involving large vessel occlusions of the anterior circulation which were intervened upon using the Zoom71 aspiration catheter were retrospectively analyzed. 71 passes, among 50 patients, among 7 operators, were analyzed with respect to Zoom71 catheter tip orientation with respect to the following corners: “Corner 1”‐ posterior vertical to horizontal portion of cavernous segment, “Corner 2”‐ ophthalmic turn, and “Corner 3”‐ ICA terminus to M1. The catheter tip orientation Was described as “UP” vs “DOWN” with respect to the inner curve of each corner. We also took note of whether the tip was “caught up” in the aforementioned corners during navigation. Results There was no preferential angled tip orientation of the Z71 as its navigated around the carotid siphon: Corner 1 (posterior vertical to horizontal cavernous), 51% (N=36) UP vs 44% (N=31) DOWN, p= 0.54; Corner 2 (ophthalmic), 46.5%(N=33) UP vs 53.5% (N=38) DOWN, p= 0.55; Corner 3 (terminus to M1) 43.7% (N=31) UP vs 46.5% (N=33) DOWN, p=0.63. It was not caught up in Corner 1. It got caught up in Corner 2 in 15.5% (N=11) of passes. The UP orientation at Corner 2‐ with Z71 angled tip pointing towards the ophthalmic (away from the inner curve), was associated with getting caught in 21% (7/33) of passes vs 10.5% (4/38) for the DOWN orientation though this was not statistically significant, p= 0.22. It got caught up in Corner 3 in 4.7% (N=3/64) of passes. The UP orientation at Corner 3 was associated with getting caught in 6.5% (2/31) of passes vs 3% (1/33) for the DOWN orientation, p=0.52. Usage of Z88 as guide catheter may be associated with Z71 getting caught up less in Corner 2 compared to other guide Catheters, 9.3% (4/43) for Z88 vs 25% (7/28) for “Others”, p= 0.07. This also applied to corner 3, 0% for Z88 vs 11.1% (3/24) for “Others”, p=0.038. Conclusion There is no preferential orientation of the angled tip of the Z71 as it navigates around the carotid siphon. The DOWN orientation may allow for better trackability around the ophthalmic turn. Usage of Z88 as guide catheter may help with Z71 trackability around the siphon.

Evolving Clinical-Translational Investigations of Cerebroprotection in Ischemic Stroke.

Ischemic stroke is a highly morbid disease, with over 50% of large vessel stroke (middle cerebral artery or internal carotid artery terminus occlusion) patients suffering disability despite maximal acute reperfusion therapy with thrombolysis and thrombectomy. The discovery of the ischemic penumbra in the 1980s laid the foundation for a salvageable territory in ischemic stroke. Since then, the concept of neuroprotection has been a focus of post-stroke care to (1) minimize the conversion from penumbra to core irreversible infarct, (2) limit secondary damage from ischemia-reperfusion injury, inflammation, and excitotoxicity and (3) to encourage tissue repair. However, despite multiple studies, the preclinical-clinical research enterprise has not yet created an agent that mitigates post-stroke outcomes beyond thrombolysis and mechanical clot retrieval. These translational gaps have not deterred the scientific community as agents are under continuous investigation. The NIH has recently promoted the concept of cerebroprotection to consider the whole brain post-stroke rather than just the neurons. This review will briefly outline the translational science of past, current, and emerging breakthroughs in cerebroprotection and use of these foundational ideas to develop a novel paradigm for optimizing stroke outcomes.