M1 Segment Research Articles

CT and Angiographic Findings among COVID-19-Positive Patients Presenting with Stroke and Their Outcomes

Abstract Background The study aims to assess and compare the computed tomographic and angiographic findings and clinical outcomes among coronavirus disease 2019 (COVID-19)-positive and COVID-19-negative patients. Methods We conducted a retrospective study of all patients presenting with acute stroke to our facility between March 2020 and October 2021. Demographics, risk factors, COVID-19 status, National Institute of Health Stroke Scale (NIHSS), mode of treatment, length of hospital stay, imaging findings, and angiographic and clinical outcomes were extracted from electronic medical records. Descriptive statistics were used to summarize the data. Pregnant patients, those under the age of 18, and those found to have an alternative diagnosis were excluded. We identified 103 patients with acute stroke who underwent thrombolysis and/or mechanical thrombectomy, 16 of whom were found to be COVID-positive (study group), while 87 of them had negative status (control group). Results The mean age of both groups (COVID-19 positive and COVID-19 negative) was 56 years, and 85% were male. The most frequently involved vessel was the M1 segment of the middle cerebral artery (37% in COVID-19-positive patients vs. 41% in COVID-19-negative patients). Sixty-one patients underwent thrombectomy, and both groups had comparable successful recanalization. Patients with COVID-19 infection were more likely to have a more extended hospital stay and a higher average NIHSS score at discharge. Conclusion Our study shows that ischemic stroke in COVID-19 occurs in predominantly male patients, with the middle cerebral artery being the most frequently involved vascular territory. Furthermore, there is a longer hospital stay and worse morbidity regardless of the mode of treatment and imaging findings in COVID-19-positive patients.

Pedunculated left endoventricular thrombosis complicated by cerebral stroke in patient with suspected peripartum cardiomyopathy: A case report

Peripartum cardiomyopathy (PPMC) is an infrequent form of cardiomyopathy, whose main presentation is characterized by systolic dysfunction that commonly emerges in the early postpartum period. Acute heart failure symptoms such as congestion and dyspnea are common manifestations of PPMC. Here, we present a case of a 32-year-old female who, after hospitalization, manifested dyspnea and thoracic pain linked to the findings a left endoventricular thrombus. After the admission to the intensive cardiovascular care unit, heart failure and anticoagulant therapies as well as non-steroidal anti-inflammatory drugs were administered, leading to initial improvement of the left ventricular global function. Five days after the treatment, the patient experienced aphasia and right hemiplegia. The cerebral angiography documented an M1 segment occlusion. After treating the occlusion with stent retriever thrombectomy, the symptoms regressed and she attained full recovery. Therefore, surgical thrombectomy should be prioritized as the treatment approach to removing the pedunculated left ventricular thrombus, considering the apical morphology of the pedunculated left ventricular thrombus and if the anticoagulant therapy gives rise to side effects.

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 201: Feasibility of an 088” Catheter in the M1 segment for Mechanical Thrombectomy

Introduction Placement of 088” aspiration catheters in the internal carotid artery (ICA) for aspiration in mechanical thrombectomy (MT) has been previously described. However, the use and safety of 088” aspiration catheters beyond the ICA has not been established. Here, we report the utilization and early safety outcomes of 088” catheter placement in the M1 segment for MT. Methods We reviewed a prospectively maintained IRB‐approved database of the senior author to identify consecutive cases where the 088” catheter was navigated to the MCA for use in mechanical thrombectomy. Results We identified 13 cases with placement of an 088” aspiration catheter in the MCA segment (all cases performed in 2023). Average patient age was 71±4 years (range 56‐97 years), with 10 (77%) females, presenting NIHSS was 12±2.1, and 3 (23%) patients received tPA. Location of the thrombus includes 7 (54%) in the M1 and 6 (46%) in the M2. In 13 (100%) cases, the Zoom88 (OD = 2.7 mm, Imperative Care, Campbell, CA) catheter was advanced to at least the M1 segment, and it was used with a coaxial Zoom71 catheter. The average M1 diameter prior to MT was 2.5±0.2mm, 2.3±0.2mm, and 2.2±0.1 in the proximal, mid, and distal M1‐segment, respectively. After MT, the average M1 diameter was 2.4±0.1mm, 2.2±0.1mm, and 2.1±0.2mm in the proximal, mid, and distal M1‐segment, respectively. 85% (n=11) of cases used one or more stentrievers including a Tigertriever, Solitaire, and Trevo. Average number of passes was 1.9±0.2. There were no vessel perforations, catheter‐related dissections, or hemorrhagic complications noted in any case. TICI 2C/3 recanalization was achieved in 100% of cases. The average mRS on discharge was 1.2±0.4. Figure 1. (A) AP angiography demonstrating an M1 branch occlusion (orange). (B) Native view, 088” catheter under aspiration in the MCA (green). (C) Post‐thrombectomy final angiography demonstrating TICI 3 reperfusion. Conclusion The use of large‐bore 088” aspiration catheters in the MCA may offer a safe strategy for direct clot ingestion during mechanical thrombectomy in MCA vasculature that is smaller than the 8‐Fr aspiration catheter.

Abstract 002: Examining Pulling Force Using Combined Stentreiver and Aspiration Technique in a Medium Vessel Thrombectomy Model

Introduction With the advent of smaller stent retrievers (SR) and aspiration catheters (AC) capable of accessing more distal locations, distal and medium vessel occlusions (DMVO) are emerging as promising targets for endovascular thrombectomy (EVT). However, considering the vulnerability of distal vessels to injury, it is imperative to understand the safety of various frontline techniques in these challenging scenarios. Using a vascular flow model, we sought to investigate the optimal size, strategy, and positioning of a stent retriever and aspiration catheter to minimize the pulling force exerted on the M2 vasculature. Methods We used a silicone vascular flow model with moderate tortuosity that replicated the left‐sided anterior circulation, including middle cerebral artery (MCA) branches in the M2 territory. An 8 French Cook Shuttle guide sheath was inserted coaxially with a Catalyst 7‐132 cm aspiration catheter and TrevoTrak 21 microcatheter. To measure pulling force, an Imada force gauge DST‐1A was placed at the M2 and a DST‐11A at the proximal end of the microcatheter. The Solitaire 4x20 mm Solitaire stent‐retriever was pulled at 4 mm/sec with the AC in the proximal cavernous carotid segment (NoAsp), proximal M1 (M1P), and distal M1 (M1D), a total of 8 times per AC position, using the ingestion technique. The pinching technique was also examined using the 4x20mm stent. Results The average pulling force measured on M2 using the 4x20mm stent was 169.1mN with the AC docked in the proximal NoAsp position, 26.5mN with the AC at M1P, and 23.0mN at M1D (p<0.0001). The difference in pulling force between M1P and M1D was not significant (p=0.472). The average pulling force exerted on M2 from pinching the 4x20mm stent with the AC at M1D, rather than ingestion of the stent at M1D, was 62.9mN. Average pulling force was noted to decrease from the first to the last run in most cases, with an average drop of 26.4% at the fourth run. Conclusion ADAPT and stent‐retrieval have recently been shown to be comparable in DMVO (1), however some studies have suggested a combined approach may reduce bleeding complications compared to stent‐retrieval alone (2). In our in‐vitro model, we demonstrated that positioning the AC in M1 (M1D or M1P) reduced the pulling force exerted by the stent‐retriever on M2 compared with AC placement in the cavernous carotid (NoAsp). The pulling force exerted from pinching the 4x20mm stent with the AC at M1D was higher than with the ingestion technique, for which the explanation is uncertain, but may be due to the additional friction in the M1 segment. Taken together, these findings suggest a combined approach decreases frictional pulling force during stent‐retrieval and is safer than SR alone. We also note that the pulling force of each stent decreased after its third usage, in line with the manufacturer’s instructions for use, which suggest no more than 3 retrievals per stent (3). Future experiments will compare a wider range of techniques using stents of varying sizes to better clarify factors associated with decreased pulling force in EVT.

Abstract 202: Early Experience with the Aristotle Colossus 035” Micro‐Guidewire for Mechanical Thrombectomy: Experience in 6 Cases

Introduction Recent literature continues to demonstrate the successful role large‐bore aspiration catheters have in thrombus ingestion during mechanical thrombectomy. However, the ledge gap, or step off, between the catheter and the microwire can make navigating to distal vasculature difficult. A new 035” micro‐guidewire reduces the step off for 035” aspiration catheters (Aristotle 35 Colossus Guidewire, Scientia Vascular, West Vale City, UT) while maintaining torquability and softness. We report here our early experience in 6 mechanical thrombectomy cases. Methods We reviewed and analyzed a prospectively maintained database of the senior authors to identify cases utilizing a 035” micro‐guidewire with 035” aspiration catheters in mechanical thrombectomy. Results Six consecutive cases of 035” microwire use for mechanical thrombectomy were identified. Four (67%) patients were female with an average age of 77±5.3 years (range 56‐97). Average presenting NIHSS was 11±3. Thrombus locations included 50% (n=3) in the M2, 33% (n=2) in the M1, and 17% (n=1) in the P1. Radial access was performed in 1 case (17%), with remaining via femoral access (n=5, 83%). An 088” ID aspiration catheter was navigated to at least the M1 segment in all anterior circulation cases and the basilar in the posterior circulation case. The 035” wire was placed proximal to the occlusion in all cases allowing coaxial 035” and 071” catheter aspiration passes. The average number of passes was 2±0.3. TICI 2C/3 was achieved in 83% of cases (5/6) and 2b in the remaining case. There were no catheter‐related dissections, perforations, or hemorrhagic complications noted for the cases. Figure 1. (A) AP angiography demonstrating a thrombus in the right M2 superior division (white). (B) 035” (yellow), 071” (orange), and 088” (red) aspiration catheters over the Colossus 35 micro‐guidewire (black) at the level of the thrombus without crossing it. Conclusion The Colossus 035” micro‐guidewire may offer advantages over its narrower counterparts by reducing ledge effect and the need to cross the thrombus. Further comparative studies against currently available microwires are needed in various anatomies to confirm this perceived performance advantage.

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 217: Influence of CT Perfusion on Decision‐Making for Endovascular Thrombectomy in Distal Occlusions: A Multi‐center Analysis

Introduction There is increasing interest in performing endovascular thrombectomy (EVT) for distal occlusions. Decision making for distal and medium vessel occlusions (DMVO) is variable and factors associated with undergoing the treatment at present remain incompletely characterized. Methods From our prospectively maintained multi‐center registry encompassing four comprehensive stroke centers in the greater Houston area, we identified patients with DMVO acute ischemic stroke (AIS). Patients with occlusions in and beyond the M2 segment, A2 segment, and P2 segment were included. The primary outcome was the likelihood of undergoing EVT, which was analyzed using multivariable logistic regression. We adjusted for time of day of presentation, NIHSS score, ASPECTS, and TPA administration, with the primary independent variable being whether CTP was used in the patient’s evaluation. Secondary outcomes included discharge modified Rankin Scale (mRS), dichotomized 0‐3 vs. 4‐6 Results Among 269 patients with distal occlusions, the median age was 68 (IQR 18), median NIHSS score was 12 (IQR 11), 47.2% were female, and 39.4% received TPA. The most common occlusion locations were M2 (77.7%) followed by P2 (9.7%), and 12.6% comprised the remainder of the occlusions. 166 (61.7%) underwent CTP and 37.9% underwent EVT. Median infarct core on CTP was 18.8 cc and penumbra was 83.1 cc. In multivariable analysis, patients evaluated with CTP were less likely to undergo EVT (OR 0.56 [95% CI ‐1.11;‐0.02]). CTP usage was also associated with a non‐significant reduced likelihood of good discharge outcome (OR 0.59, [95% CI 0.33;1.02]). Conclusion In our multi‐center cohort, patients with DMVO screened with CTP were nearly 50% less likely to undergo EVT. While the modality may assist with occlusion detection, it may also influence whether treatment is offered.

Abstract 064: The Pushability of Commonly Used Microwires in Neuroendovascular Procedures

Introduction In distal and medium‐vessel occlusions (DMVOs), there are increasing opportunities to deliver devices through tortuous and medium sized arteries. However, this comes at the risk of microwire perforation during distal microcatheter advancement for navigation in these curved, slender vessels, leading to hemorrhagic complications. Currently, microwires with a range of stiffness levels are available. However, it is unclear how the variations in stiffness and the relative positioning of the microwire and microcatheter may affect the force applied to the vessel wall. Few studies have compared objective metrics across different commonly used devices. We sought to compare the pushability of various Synchro Select and Chikai microwires using both proximal and distal support. Methods In a moderate tortuosity, silicone flow model of the middle cerebral artery (MCA) branches, we tested 0.014” nitinol microwires (Synchro Select Soft, Standard, or Support), or 0.014” stainless steel microwires (Chikai, Black, and Black Soft) in a TrevoTrak 21 microcatheter docked either in the proximal M1 segment or distal M2 segment. Applied force was measured using an Imada force gauge DST‐1A at the M2 ten times for each experiment. The slope, measured in mN per mm, of the applied distal force during the maximal pushing period was calculated. Results The average slope of the pushing force within a distal microcatheter was 10.64 mN/mm with a Synchro Soft, 10.85 mN/mm with a Standard, and 15.28 mN/mm with a Support microwire (p < 0.0001). The average slope of the pushing force in a proximal microcatheter was 1.61 mN/mm with a Synchro Soft, 3.15 mN with a Synchro Standard, and 3.87 mN with a Synchro Support microwire (p <0.001). With the Chikai microwires, the average slope of the pushing force within a distal microcatheter was 12.48 mN/mm with a Chikai Black Soft wire, 12.82 mN/mm with a Chikai Black microwire, and 14.11 mN/mm using a Chikai microwire (p=0.801). Within a proximal microcatheter, the average maximal force was 2.42 mN/mm using a Chikai Black Soft wire, 3.16 mN/mm using Chikai Black, and 3.91 mN/mm using the Chikai wire (p < 0.001). Conclusion This study demonstrated that stiffer microwires push the arterial wall with significantly greater force within a microcatheter close to the wall. Pushability of the microwire significantly dropped across all microwires when the microcatheter was positioned more proximally. This is the first known report of the pushability of commonly used microsystems in neuroendovascular procedures.

Abstract 115: Carotid Intraluminal Thrombus Obscuring Underlying Carotid Web: Case Report

Introduction Carotid webs (CaW) have been increasingly recognized as a unique cause of recurrent ischemic strokes.1 They are defined as thin, intraluminal, shelf‐like lesions along the posterior aspect of the carotid bulb.1,2 Despite more awareness and ongoing studies into their pathogenesis, diagnosis, and management,3 they are still overlooked in clinical practice as a primary carotid ischemic etiology. Our case describes a patient with right extracranial internal carotid artery (ICA) thrombus secondary to later‐diagnosed CaW on close follow‐up imaging. Methods We report a 55‐year‐old African American man with history of hypertension, type 2 diabetes mellitus and hyperlipidemia presented with acute onset slurred speech and left facial droop (FP). His last known well was 24 hours prior to presentation, and NIHSS upon arrival was 3 (FP 2, dysarthria 1). CT angiography (CTA) of the head and neck demonstrated a nearly occlusive thrombus of the distal right M2 segment MCA as well as non‐hemodynamic stenosis of the proximal right ICA with possible underlying sidewall filling defect‐appearing lesion concerning for a posterior wall thrombus without underlying atherosclerosis at the bulb or otherwise. The patient was admitted to the neurovascular intensive care unit and started on aspirin and high‐risk heparin drip. His MRI Brain demonstrated multiple acute/subacute right MCA territory strokes, predominately in the right posterior insula, right frontal lobe, and right posterior corona radiata. His stroke workup was otherwise unrevealing, and he was discharged on apixaban 5mg BID. Results Close surveillance follow‐up imaging with CTA head and neck was planned and obtained one month later, which demonstrated resolution of the filling defect that was obscuring the currently visualized underlying right CaW pocket (Figure‐1). The prevalence of CaWs has been reported to be between 1.2% and 2.5% of patients with acute ischemic stroke. CaWs are most frequently seen in younger, female patients, and patients with these lesions are at increased risk of recurrent stroke.4,5 Determining the optimal management for these lesions remains essential, but the available data thus far have not been conclusive. Most patients are treated with antiplatelet therapy, but some elect to treat with anticoagulation due to the focal hemostasis caused by CaWs.6 However, multiple studies have suggested that medical management alone is likely not sufficient in reducing the recurrent stroke risk caused by CaWs.5,7 Neuro‐interventional procedures including carotid artery stenting have been reported as secondary prevention strategies in patients with recurrent strokes.5,7,8 Although data regarding the rate of recurrence of strokes secondary to these lesions remains unclear, the current data does suggest benefit and safety in pursuing carotid stenting to prevent recurrent strokes.5‐8 Conclusion In young patients with proximal ICA thrombosis without underlying atherosclerosis or other conventional stroke risk factors, CaW should be considered among other differentials including hypercoagulable status. Following acute medical management, short‐term surveillance imaging is essential to confirm or rule out the diagnosis. In our case, the patient’s proximal ICA thrombus resolved after short course of anticoagulation and was determined to be secondary to the obscured underlying CaW.

Abstract 109: Endonasal Endoscopic Approach Associated Cerebral Vasospasm and Management: A Case Report

Introduction Endoscopic endonasal approach(EEA) techniques have been increasingly utilized and have been associated with development of cerebrospinal fluid(CSF) leak, meningitis, diabetes insipidus post‐operatively. Cerebral vasospasm following EEA has rarely been described. Here, we describe the clinical course and management of a patient who underwent EEA for encephalocele repair whose course was complicated by postoperative subarachnoid hemorrhage(SAH) and cerebral vasospasm. Methods n/a Results Case Presentation: 40 year old female with past medical history significant for cerebral venous sinus stent on aspirin, CSF rhinorrhea secondary to right nasal encephalocele s/p endoscopic transnasal transethmoidal repair with nasoseptal flap reconstruction and lumbar drain placement eleven days prior presented with speech difficulties and right sided weakness. On exam, patient was noted to have mild right hemiparesis and expressive aphasia. MRI brain showed subacute infarcts in left greater than right frontal lobes, corpus collosum and right anterior perforated substance. MRA head demonstrated multifocal arterial stenosis. In light of postoperative CT head showing SAH in the basilar, perimesencephalic, prepontine cisterns, interhemispheric fissure and right frontal sulci as well as intraventricular hemorrhage in fourth ventricle, her presentation was thought to be secondary to cerebral vasospasm in the setting of postoperative SAH. She was treated with intravenous hydration, permissive hypertension with head of bed in flat position and transferred for further evaluation. On arrival, she continued have mild right hemiparesis and aphasia. Repeat CTA head/neck and CT perfusion showed severe stenosis of bilateral M1 segments and left greater than right A1 segments as well as ischemic penumbra in left ACA/MCA watershed territory. Diagnostic cerebral angiogram showed bilateral severe A1 stenosis and mild to moderate bilateral M1 and supraclinoid ICA stenosis which improved with intra‐arterial verapamil. She was started on nimodipine. Systolic blood pressure was augmented with vasopressors for goal of 150‐180mmHg. Daily TCDs were followed. She developed worsening right leg weakness following day, thus she was taken for repeat diagnostic cerebral angiogram during which time she was re‐administered intra‐arterial verapamil with improvement in vasospasm. After the second treatment, she had improvement in speech and motor strength. Systolic blood pressure goal was gradually normalized. She was noted to have incidental left internal jugular (IJ) vein thrombosis for which anticoagulation was held in the setting of recent neurosurgical procedure and SAH. Workup for vasculitis and hypercoagulability was unrevealing. Lumbar puncture demonstrated 13 WBC/cu mm with lymphocytic predominance(90%), 23 RBC/cu mm, glucose 89mg/dl, protein 30mg/dl. CSF cultures were negative. Pleocytosis in CSF was attributed to recent neurosurgical procedure. Her neurological exam improved to baseline on hospital day(HD) 9.On HD12, she was found to have left common femoral deep venous thrombus in addition to the left IJ thrombus. Anticoagulation with low dose heparin infusion was started which was transitioned to apixaban on discharge. She was discharged home on HD20. Conclusion We report a case of EEA associated with severe multifocal cerebral vasospasm secondary to postoperative SAH that was successfully treated with induced hypertension, oral nimodipine and intra‐arterial verapamil as an adjunct therapy with an excellent outcome.

Salvage Maneuvers for Occluded Bypass in Cerebral Revascularization Procedures

ObjectCerebral revascularization is an effective measure for dealing with complicated intracranial aneurysms and ischemic cerebro-vascular disease. Intra-operative thrombosis causing bypass occlusion is a severe issue that cause devastating consequences for complication in revascularization. We report our experiences regarding salvage maneuvers for intraoperative thrombosis in cerebral revascularization procedures and discuss the characteristics and culprits. MethodsWe investigated 720 consecutive patients who underwent cerebral revascularization at the First Affiliated Hospital of Soochow University from January 2013 to October 2021, including 688 patients who underwent superficial temporal artery (STA)-middle cerebral artery (MCA) bypass and 32 patients who underwent extracranial artery-radial artery (ECA-RA)-MCA bypass. Forty-one patients experienced intracranial aneurysms, and the remaining 679 patients was involved in moyamoya disease (MMD), skull base tumors, intracranial occlusive vascular diseases, or other cerebrovascular diseases. All clinical characteristics, clinical imaging examinations and neurological outcomes were studied pre- and postoperatively. The patency of bypasses was confirmed by intraoperative doppler ultrasonography and indocyanine green (ICG) videoangiography. ResultsSeven intraoperative thromboses, which were confirmed by intraoperative doppler ultrasonography and ICG videoangiography, including STA-MCA bypass (n=5) and ECA-RA-MCA bypass (n=2), were observed in 720 patients who underwent cerebral revascularization. The anastomotic stoma remained patent in 6 of 7 patients with intraoperative thrombosis after treatment. One case in STA-MCA bypass failed to be salvaged. Of the four intraoperative thrombosis in STA-MCA bypass for MMD being successfully saved, two were salvaged by applying gelfoam around the site of the anastomosis to relieve the downward compression effect of the donor vessel(STA) on the recipient vessel(M4 segment of MCA).One case in ECA-RA-MCA bypass were salvaged by thrombectomy through donor arteriotomy (radial artery) and reanastomosis. The other case was salvaged by complete reanastomosis. All seven patients who experienced intraoperative thrombosis achieved favorable outcomes at discharge and the 6-month follow-up. ConclusionVarious factors are responsible for intraoperative thrombosis in cerebral revascularization. Relieving the downward compression effect of the donor vessel STA on the recipient vessel M4 segment of MCA by applying gelfoam around the site of the anastomosis stoma, can be recommend to salvage the intraoperative thrombosis in cerebral revascularization.

Stent assisted coil embolization for a dissecting cerebral aneurysm of middle cerebral artery: A case report and the literature review

Background: Dissecting aneurysms of the middle cerebral artery (MCA) are very rare. We herein report a case of an unruptured dissecting aneurysm of the MCA treated by stent-assisted coil embolization. Case Description: A 65-year-old man with no history of trauma presented with a headache. Time-of-flight imaging revealed a dissecting cerebral aneurysm in the right M1 segment of the MCA, and the aneurysm had increased in size within a short time. We treated the aneurysm by endovascular stenting with coils, and the patient developed no neurological deficits. Conclusion: Because of the potential involvement of the lenticulostriate artery (LSA) in the area of dissection, choosing the best treatment (such as direct surgery or endovascular treatment) may be challenging. Treatment efficacy depends on whether the LSA is affected and on the length of the dissection. In our case, the dissection did not involve the LSA and could therefore be treated by stent-assisted coil embolization.

In vitro comparison of manual and robotic endovascular thrombectomy for acute ischemic stroke.

Robotic endovascular systems have the potential to reduce radiation exposure to physicians and expand timely neurointerventional access to patients in remote areas. The goal of the study was to determine the feasibility of robotic endovascular thrombectomy (EVT) in an in vitro model. In vitro procedures were conducted manually and robotically using the Corpath GRX robotic system in a human vascular simulator with an elastic ovine clot in the M1 segment of the left middle cerebral artery. Due to the limited device compatibility of the CorPath GRX, a simple technique with a stent retriever and guiding catheter without a balloon was used in the study. Seven robotic EVT and manual EVT were carried out in each group. Metrics including procedural time, success rate, and radiation dose were compared between the two groups. In robotic EVT, the mean total preparation and procedural time was 892 s, which was significantly longer than manual operation at 357 (p = 0.0001). There was no significant difference in the success rate between the two approaches (robotic: 28.6% vs. manual 42.9%, p = 0.577). The mean radiation exposure to operating physicians was significantly lower during robotic operation compared to manual operation (0.02 μSv vs. 0.22 μSv, p < 0.0001). Robotic EVT was feasible in our human vascular simulator with significantly reduced radiation exposure to the operating physicians, despite an increased length of procedure when compared to manual procedures. Future technological advancement is warranted for reducing procedural length using endovascular robotic techniques.

Microsurgical treatment of distal middle cerebral artery aneurysm: A single-center review.

To review the characteristics of distal middle cerebral artery (MCA) aneurysm treated by microsurgery, the detailed surgical options, and the clinical result. We retrospectively reviewed cerebral aneurysm in the M2 and M3 segments of the MCA surgically treated between January 2015 and December 2022. The demographic data, aneurysm-related findings, type of surgical approach, surgical technique, and clinical outcomes of the enrolled patients were analyzed. Sixteen distal MCA aneurysms were treated with microneurosurgery (incidence, 1.0%; female, 12; mean age, 58.1 years; ruptured, three). Twelve aneurysms were in the M2 segment (insular segment), two aneurysms at the M2-M3 junction, and two aneurysms in the M3 segment (opercular segment). Twelve aneurysms were saccular (average size, 4.9 mm; multiplicity, 50%; average aneurysms, 3.0; partially thrombosed, 1; sidewall aneurysm, 2). Three aneurysms were fusiform, of which two were ruptured. Of the ruptured aneurysms, one was a ruptured dissecting aneurysm. The trans-sylvian and trans-sulcal approaches were used in fourteen and two patients, respectively. Neck clipping, wrap clipping, and surgical trapping were performed in twelve, one, and one patient, respectively. Proximal occlusion was performed in one patient. Bypass technique was required in two patients (neck clipping and proximal occlusion). The modified Rankin Score was 6 in the two patients with ruptured aneurysms. The remaining patients did not show further neurological deterioration after microneurosurgery. Distal MCA aneurysms had a high incidence of being diagnosed with multiple other aneurysms and were relatively non-saccular.

Safety and efficacy of the Low-Profile Visualized Intraluminal Support stent in treating intracranial atherosclerotic stenosis

PurposeThe performance of the Low-Profile Visualized Intraluminal Support (LVIS) stent deployed following balloon angioplasty is unknown in treating intracranial atherosclerotic stenosis, and this study was to investigate the safety and efficacy of the LVIS stent in treating intracranial atherosclerotic stenosis in the middle cerebral artery M1 segment. MethodsThirty-five patients were enrolled with 35 atherosclerotic stenoses at the M1 segment. The stenosis was about 75% in 16 patients, 80% in 15, and 90% in the rest four. The LVIS stent was used to treat these patients. ResultsThe success rate of stenting was 97.1%. The stenting procedure was failed in one patient because of intraprocedural dissection of the stenotic (75%) segment, resulting in a 30-day periprocedural complication rate of 2.9% (1/35). Before stenting, the stenosis rate ranged 75%–90% (mean 78.9%±4.7%), and after stenting, the diameter of the stented segment was significantly (P<0.0001) increased to 1.5–3.4mm (mean 2.1±0.32mm) ranging 68.2%–100% (mean 94.0%±5.8%) of the normal arterial diameter, with the residual stenosis ranging 0–31.8% (median 4.8%, IQR 2.4%–7.3%). Follow-up was performed at 6–20 months (mean 8.5) after stenting. One patient (2.9%) had occlusion of the stented M1 segment with no symptoms, and two patients (5.7%) had slight asymptomatic instent stenosis (40%) at the M1 segment, with the instent restenosis and occlusion rate of 8.6% (3/35). ConclusionThe braided LVIS stent can be safely applied for treatment of intracranial atherosclerotic stenosis in the middle cerebral artery with good safety and efficacy immediately after stenting and at follow-up.

The effect of distal aspiration catheter position on collateral flow in mechanical thrombectomy - an in vitro study.

Endovascular mechanical thrombectomy for ischaemic stroke is one of the most effective treatments. Despite the devices and techniques that have been developed, thrombi are not always successfully retrieved. The incidence of futile reperfusion after successful clot retrieval also remains a major concern. We hypothesise that simply placing an aspiration catheter in the system compromises collateral flow which may have an impact on functional outcomes. An in vitro study was conducted using a physical pulsatile flow model designed in glass to mimic the anterior cerebral circulation with middle cerebral artery M1 segment occlusion. A 5Fr aspiration catheter was positioned at the supra-clinoid internal carotid (SC-ICA), carotid terminus (T-ICA) and M1. For each catheter position, the flow rate through the model's anterior cerebral (ACA) and posterior communicating (PCOM) arteries was measured (no aspiration applied). Our results showed significant mean percentage flow reductions in the ACA and PCOM with the catheter positioned at the SC-ICA (PCOM 59.14% ± 0.93, ACA 59.52% ± 0.82, p < 0.001), T-ICA (PCOM 81.54% ± 0.55, ACA 85.65% ± 1.54) and M1 (PCOM 75.79% ± 0.98, ACA 84.20% ± 0.43) (Mann-Whitney U Test, p < 0.001). These results indicate a significant reduction in collateral flow following the insertion of a wide bore catheter in an in vitro model. In a clinical setting, this could have an impact on patient outcome, particularly in prolonged procedures and those requiring several passes to achieve recanalisation.

Application of high-resolution magnetic resonance vessel wall image in the treatment of M1 segment stenosis of middle cerebral artery

To investigate the application of high-resolution magnetic resonance vessel wall image (HRMR-VWI) in treating middle cerebral artery (MCA) M1 segment stenosis. We retrospectively analyzed preoperative clinical data, imaging data, preoperative evaluation, stent procedure, and postoperative complications in 35 patients with atherosclerotic stenosis of the MCA M1 segment. And the 30-day postoperative mortality and disability and the 12-month restenosis were followed up. There were 21 males and 14 females, with a median age of 55 and a median duration of 1 month from onset to stenting. DSA confirmed that the stenosis locates in the M1 segment, with a stenosis degree of (75.00±17.15) %, a stenosis length of (4.34±1.51) mm, and a blood vessel diameter of (2.25±0.42) mm. After the operation, there was 1 case of death after a craniotomy to remove hematoma+decompression due to reperfusion hemorrhage. There were two technical complications during the procedure (1 case of asymptomatic occlusion of the A1 segment due to the covering of stent at the initial part of A1, 1 case of intraparenchymal hematoma in the temporal lobe due to penetrating distal small blood vessel with guide wire). HRMR-VWI is of great value in observing plaques' location, morphology, and stability. It can improve the safety and effectiveness of stenting treatment of MCA M1 segment stenosis.

Partial (SAVE) versus Complete (Solumbra) Stent Retriever Retraction Technique for Mechanical Thrombectomy: A Randomized In Vitro Study.

Mechanical thrombectomy has become a first-line treatment for acute ischemic stroke. Several techniques combining stent retrievers and distal aspiration catheters have been described. We aimed to characterize the efficacy of 2 commonly used techniques according to clot characteristics. Soft (mean stiffness = 95.77 [SD, 5.80] kPa) or stiff (mean stiffness = 205.63 [SD, 6.70] kPa) clots (3 × 10 mm and 2 × 10 mm, respectively) were embolized to the distal M1 segment of the MCA in an in vitro model. The technique was randomly allocated (1:1): stent retriever assisted vacuum-locked extraction (SAVE) versus complete retraction (Solumbra). The primary end point was the percentage of first-pass recanalization. Secondary end points were periprocedural distal embolization measures. A total of 130 mechanical thrombectomies were performed (50 for soft clots and 15 for stiff clots per arm). Overall, the rate of first-pass recanalizaton was 35% with Solumbra and 15% with SAVE (P < .01). For stiff clots, the first-pass recanalizaton was equal for both methods (27%; P = 1.00). With soft clots, the first-pass recanalizaton was higher with Solumbra (38%) than with SAVE (12%; P < .01). When we used soft clots, the maximum embolus size (mean, 1.19 [SD, 0.9] mm versus 2.16 [SD, 1.48] mm; P < .01) and total area of emboli (mean, 1.82 [SD, 2.73] versus 3.34 [SD, 3.2]; P = .01) were also lower with Solumbra than with SAVE. Clot characteristics may influence the efficacy of the thrombectomy technique. In occlusions caused by soft clots, complete retrieval into the distal aspiration catheters achieved higher rates of first-pass recanalizaton and lower embolization.