Cervical Internal Carotid Artery Research Articles

Stroke Secondary to Fibromuscular Dysplasia

FMD is a rare systemic vascular disease characterized by abnormal cell proliferation in the artery walls, leading to artery narrowing, twisting, or bulging. It commonly affects the carotid and renal arteries and can result in renal diseases and stroke. This paper presents a case study of a 39-year-old unhoused female patient who experienced a stroke secondary to fibromuscular dysplasia (FMD) and left ventricular thrombus. The patient presented with asymmetric movement of the extremities and psychosis, so intoxication was initially suspected. However, further examination revealed facial asymmetry and motor weakness. CT scans showed a left anterior cerebral artery infarction and irregular contour of the cervical internal carotid arteries, consistent with FMD and carotid thrombus. Management involved stabilizing the patient, providing supportive treatment, and controlling blood pressure. Thrombolytic therapy was not administered due to the time elapsed since symptom onset. The patient was started on anticoagulation for the carotid plaque and left ventricular thrombus. A transthoracic echocardiogram revealed a large left ventricular thrombus and left atrial enlargement, and the patient was started on heart failure medications. FMD and left ventricular thrombus are not directly related, but FMD can contribute to thrombus development through its impact on the cardiovascular system, including hypertension, arterial wall damage, aneurysm development, or dissection. Treatment for FMD may involve medication, observation, or surgical interventions like angioplasty and stenting. Anticoagulation therapy is essential for managing the left ventricular thrombus. This case highlights the importance of early diagnosis and treatment of FMD to prevent complications such as stroke. It is important to consider FMD in the diagnosis of younger patients with a stroke, especially those with a history of hypertension, substance abuse, or other risk factors. Further research is needed to better understand the relationship between FMD and stroke and to optimize treatment strategies for these patients.

Carotid artery stenting after balloon aortic valvuloplasty in cervical internal carotid artery stenosis associated with severe aortic stenosis: A case report

AbstractCarotid artery stenting (CAS) is contraindicated in patients with severe aortic stenosis (AS). However, it is required for treating those with symptomatic internal CA (ICA) stenosis and severe AS. This is the first report of successful CAS after balloon aortic valvuloplasty (BAV) in a patient having ICA stenosis accompanied with severe AS. An 82‐year‐old man with a history of severe AS presented with amaurosis fugax due to severe stenosis at the left ICA. We performed CAS just after BAV. No perioperative complications were reported. It might be a useful treatment strategy for symptomatic ICA stenosis with severe AS.

A Novel Staged Revascularization Strategy for Bilateral Severe Internal Carotid Artery Stenosis at High Risk for Hyperperfusion Syndrome

Since bilateral severe internal carotid artery stenosis often is associated with severely decreased cerebrovascular reactivity (CVR) due to poor collateral blood flow, revascularization carries a high risk for development of hyperperfusion syndrome. In this study, we report a new staged strategy to prevent postoperative hyperperfusion syndrome in such patients. Bilateral severe cervical internal carotid artery stenosis patients with decreased CVR to 10% or less on one side were prospectively enrolled in this study. We first performed carotid artery stenting on the side with the milder CVR decrease (lower-risk side), aiming to improve hemodynamics associated with the severe CVR decrease on the greater-risk side. Then, carotid endarterectomy or carotid artery stenting was performed on the contralateral side after an interval of 4-8 weeks. In all 3 cases enrolled in this study, CVR on the greater-risk side improved to 10% or more 1 month after the first treatment. The ratio of regional cerebral blood flow on the contralateral greater-risk side was 114% 1 day after the second treatment, and HPS did not develop in any of the cases. Our treatment strategy, in which revascularization on the lower-risk side precedes that on the greater-risk side, is effective for the prevention of HPS in bilateral ICA stenosis patients.

Bailout technique for entangled stent retriever and carotid stent during tandem large vessel occlusion endovascular therapy.

Endovascular thrombectomy for patients with tandem occlusions could be challenging. Exposure to potential technical complications and bailout rescue techniques are of utmost importance. A 73-year-old woman with tandem internal carotid artery and middle cerebral artery lesions underwent an unsuccessful retrograde revascularization approach in the setting of tortuous anatomy. Antegrade approach revascularization was then pursued. Following cervical internal carotid artery revascularization, a triaxial system of aspiration catheter, microcatheter and micro guidewire was navigated through the stented curved cervical ICA and intracranial stent retriever pass was performed. Upon retrieving the clot-incorporated stent retriever with the intention to retrieve the entire stent retriever into the locally placed aspiration catheter, the triaxial system collapsed into the distal common carotid artery. Large thrombus was recovered from the aspiration catheter aspirate however the proximal end of stent retriever and distal internal carotid artery stent got tangled. After unsuccessful maneuvering to disentangle stent retriever from the internal carotid artery stent, we decided to attempt safe separation of the stent retriever from its pusher wire and leave behind the patent internal carotid artery stent/stent retriever metal construct in place. Gradual pulling pressure was applied to the stent retriever wire while maintaining distal exchange-length microwire access and fully inflated extracranial balloon over the entangled portion to ensure continuous vascular access. The stent retriever wire was then safely separated from the stent retriever and fully retracted outside the body. Delayed angiographic runs continued to demonstrate full patency of the internal carotid artery lumen. No residual dissection, spasm, or thrombus was noted. This case illustrates a novel bailout endovascular salvage technique that could be considered in such cases. These techniques minimize intraoperative complication, focus on patient safety, and promote efficiency for endovascular thrombectomy in unfavorable anatomy.

Carotid Artery Tortuosity and Internal Carotid Artery Plaque Composition.

Little is known about the association between carotid artery tortuosity and internal carotid artery atherosclerosis. This study sought to evaluate the associations between various types of arterial tortuosity and vulnerable plaque components on magnetic resonance angiography (MRA). Aretrospective review was completed of 102patients who had undergone MRA neck imaging, with intraplaque hemorrhage (IPH) present in one or both cervical internal carotid arteries (ICA). Each ICA was assessed for two categories of tortuosity: variant arterial pathway(s) (retrojugular and/or retropharyngeal) and abnormal curvature (kinks, loops, and/or coils). All ICA plaques were assessed for the presence or absence of intraplaque hemorrhage (IPH), lipid-rich necrotic core (LRNC), ulceration, and enhancement, as well as the volume of IPH and degree of luminal stenosis. The mean age of included patients was 73.5years (SD = 9.0 years) and 88 (86.3%) subjects were male. The left carotid plaque was significantly more likely to have IPH (68.6% vs. 47.1%; p = 0.02). The left ICA was more likely to have aretrojugular course (22% vs. 9.9%; p = 0.002) and any variant arterial course (26.5% versus 14.67%, p = 0.01). On the right there was an association between the presence of aLRNC and retropharyngeal and/or retrojugular arterial pathway (p = 0.03). On the left there was an association between the presence of any abnormal arterial curvature and IPH volume (p = 0.03). Neither association met the adjusted statistical threshold after Bonferroni correction, with alpha set at 0.0028. ICA tortuosity is not associated with carotid artery plaque composition, and likely does not play arole in the development of high-risk plaques.

Vessel wall imaging and carotid artery stenting for recurrent cervical internal carotid artery vasospasm syndrome: illustrative case.

Recurrent cervical internal carotid artery vasospasm syndrome (RCICVS) causes cerebral infarction, ocular symptoms, and occasionally chest pain accompanied by coronary artery vasospasm. The etiology and optimal treatment remain unclear. The authors report a patient with drug-resistant RCICVS who underwent carotid artery stenting (CAS). Magnetic resonance angiography revealed recurrent vasospasm in the cervical segment of the internal carotid artery (ICA). Vessel wall imaging during an ischemic attack revealed vascular wall thickening of the ICA, similar to that in reversible cerebral vasoconstriction syndrome. The superior cervical ganglion was identified at the anteromedial side of the stenosis site. Coronary artery stenosis was also detected. After CAS, the symptoms of cerebral ischemia were prevented for 2 years, but bilateral ocular and chest symptoms did occur. Vessel wall imaging findings suggest that RCICVS is a sympathetic nervous system-related disease. CAS could be an effective treatment for drug-resistant RCICVS to prevent cerebral ischemic events.

Hyperacute stenting and angioplasty for acute extracranial non-tandem internal carotid artery strokes within the first 48 h: A 20-year experience and a systematic review and meta-analysis.

Acute strokes involving complete, isolated occlusion of the extracranial cervical internal carotid artery (EC-ICA) with no intracranial clot burden account for a minority of stroke cases that are managed variably. Here we present our two-decade experience and a systematic review of endovascular management of acute isolated EC-ICA strokes in the hyperacute phase (<48 h) and attempt to evaluate clinical effectiveness and safety. Our prospectively maintained database was retrospectively searched for patients who presented between January 1, 2003 and December 31, 2022 with acute cervical ICA stroke confirmed on angiography. Only patients who had an isolated 100% occlusion of the cervical ICA segment and attempted acute stenting with/without angioplasty within the first 48 h of time since last known well were included. Demographics, procedural details, and outcomes were recorded. For the systematic review, a search of PubMed and Embase databases was conducted. Forty-six patients with acute, isolated EC-ICA occlusive stroke were included. Median presenting National Institutes of Health Stroke Scale (NIHSS) score was 8 (interquartile range 3-10) with a perfusion deficit in 78.3% of the 40 cases assessed with computed tomography perfusion imaging. Median time from symptom onset to intra-arterial puncture was 14.4 h. Immediate recanalization was achieved in 82.6% cases. Two cases (4.3%) of symptomatic intracranial hemorrhage (sICH) occurred postprocedure. Outcome measures were stable or improved discharge NIHSS score in 86.9% of cases, functional independence at 90 days (modified Rankin scale score ≤2) in 78.3%, and mortality in 6.5%. The systematic review included 167 patients from four articles. The estimated rate of immediate recanalization was 92.7% (95% confidence interval (CI), 88.77-96.77%), favorable outcome was 62.01% (95% CI, 55.04-69.87%), and sICH was 6.2% (95% CI, 3.41-11.32%). Stenting and angioplasty for acute cervical ICA occlusive strokes during the hyperacute phase can be performed successfully with favorable clinical outcomes and an acceptable recanalization rate.

Mechanical Thrombectomy in a 12-Month-Old Infant with Acute Ischemic Stroke Possibly due to Internal Carotid Artery Dissection: A Case Report.

Stroke in children is a rare but devastating disease. Although endovascular treatment has been reported to be safe and effective in the treatment of stroke with large vessel occlusion in this population, there are still limitations and controversies. In this case report, we describe a 12-month-old girl who was admitted to the hospital with acute onset of left-sided hemiplegia and confusion, which turned out to be due to a large infarct in the right middle cerebral artery territory, possibly caused by dissection of the right cervical internal carotid artery. Aspiration thrombectomy was successfully performed, and the patient was able to walk a few steps and raise her left upper extremity at the 12-month follow-up. The aspiration-only technique in thrombectomy may be safe and technically feasible to treat acute ischemic stroke with large vessel occlusion in children as young as 12 months, although large-volume prospective studies are needed.

Flow diversion jet: A dangerous mechanism in the flow diversion treatment of giant intracranial aneurysms.

Cerebral hyperperfusion syndrome (CHS) occurs after the restoration of blood flow to a previously low-flow, low-pressure region of the cerebral vasculature, which subsequently responds with chronic compensatory vasodilation, leading to a dysregulated state. Sudden restoration of normal blood flow can overwhelm the vasculature leading to intracranial hemorrhage (ICH). Separately, the Windkessel phenomenon describes the capacity for elastic vessels to expand with systolic pressure and decompress with diastole, thereby suppressing distal pulse pressure. We encountered a case involving giant basilar aneurysms in which we believe the Windkessel phenomenon precipitated a catastrophic manifestation of CHS at treatment. We present a 60-year-old female found to have marked dolichoectasia of the right cervical internal carotid, vertebral, and basilar arteries concurrent with two large vertebrobasilar dissecting-type fusiform aneurysms. Managed conservatively for ten years before developing gait ataxia, new imaging revealed dramatic interval growth of the larger aneurysm. Flow diversion with partial coiling of the aneurysms was pursued. The patient suffered intra-procedural catastrophic thalamic and midbrain hemorrhage with intraventricular extension. A meticulous review of the case data was undertaken. Our findings suggest that giant aneurysms can act as a Windkessel reservoir, depressing the distal pulse pressure. Flow diversion bypasses the reservoir, increasing the distal pulse pressure beyond the autoregulatory capacity, resulting in ICH analogous to CHS. CHS and Windkessel phenomenon can contribute to catastrophic sequelae in the treatment of giant intracranial aneurysms with flow diversion. Awareness of this mechanism can protect future patients from harm.

Balloon-Assisted Catheterization of Occluded Carotid Artery (BOCA) Technique in Acute Stroke.

Acute ischemic stroke from tandem occlusion of internal carotid artery (ICA) poses a technical challenge to neurointerventionalists. To present a novel balloon-assisted catheterization of occluded carotid artery (BOCA) technique used for rapid and effective catheterization of occluded/critically stenosed ICA in tandem occlusion. A retrospective review of 10 patients with tandem carotid occlusion, treated with BOCA technique for revascularization between July 2020 and June 2021, was performed. Clinical, radiographic, and procedural data; details of BOCA technique; complications; and outcomes were reviewed. Of the 10 patients, 8 (80%) had complete occlusion of the cervical ICA and the remaining 2 had high-grade stenosis with poor intracranial flow. The mean age was 63.2 years. The mean presenting NIH Stroke Scale was 13.4. The BOCA technique resulted in recanalization of ICA in all patients and allowed mechanical thrombectomy of middle cerebral artery. Thrombolysis in cerebral infarction grade 2b/3 was achieved in all 10 patients. The mean groin-to-reperfusion time was 41.4 minutes. The mean internal carotid artery stenosis was 99.7% preoperatively and 41.1% postoperatively. Only one patient needed stent at the end of the procedure because of dissection. The BOCA technique can be used in distal first approach for acute stroke from tandem ICA occlusion. This technique allows direct guide catheterization of occluded ICA by tracking over a partially inflated balloon.

Blunt Traumatic Cerebrovascular Injury and Stroke: The Need for a High Index of Suspicion when Initial Vascular Imaging is Negative - A Single Center Case Series. (P14-5.019)

<h3>Objective:</h3> NA <h3>Background:</h3> Acute ischemic stroke (AIS) from traumatic cerebrovascular injury (TCVI) leads to approximately 4800 US strokes annually; often as sequelae of cervical arterial dissection. CT angiography (CTA) is typically used for screening, but this modality has limitations of low sensitivity, particularly for low-grade dissections. Our case series illustrates the importance of high index of suspicion in trauma patients to pursue further vessel imaging when there is unexplained AIS. <h3>Design/Methods:</h3> Case series. <h3>Results:</h3> Our series consists of 2 patients admitted to Trauma ICU following motor vehicle collisions. The 1st patient was a 22-year-old woman with left precentral gyrus infarction on diffusion-weighted MRI. Initial CTA showed dissection of cervical right internal carotid artery (ICA) which did not explain her infarction. Echocardiogram was also unrevealing so digital subtraction angiography was pursued, which revealed dissection of the left supraclinoid ICA not seen on CTA. The 2nd patient was a 15-year-old man with bilateral frontal infarctions on diffusion-weighted MRI. His initial CTA showed dissection of cervical left ICA. There was no explanation for his right frontal infarction on further workup so CTA was repeated after 4 days, which showed additional dissection involving the right cervical ICA not seen initially. Etiology of AIS in both cases was unexplained initially but repeat or alternate imaging helped unveil previously undetected ipsilateral dissections. <h3>Conclusions:</h3> Undetected traumatic dissection can result in devastating neurologic sequelae including further strokes and worsening dissection. It can also lead to unnecessary workup such as thrombophilia testing in younger patients. These patients are often hidden from the view of neurologists as they are typically managed by trauma surgeons and literature regarding TCVI is predominantly in surgical journals. We hope to increase awareness and emphasize the importance of a high index of suspicion to pursue further vessel imaging in unexplained stroke so that appropriate treatment can be initiated rapidly. <b>Disclosure:</b> Dr. Asif has nothing to disclose. Dr. Habib has nothing to disclose. Dr. Samkutty has nothing to disclose.

A Case of Internal Carotid Artery Dissection Presenting With Dysgeusia (P12-5.014)

<h3>Objective:</h3> NA <h3>Background:</h3> A 42-year-old man presented to the emergency room (ER) with headache and neck pain associated with dysgeusia for three days. The headache was described as sudden, moderate, with throbbing pain, located in the left frontal region, and radiating to the left temporomandibular joint. The pain was not aggravated by chewing or position. He denied mechanical trauma to the neck including deep tissue massage or chiropractic manipulation. He had also incidentally noticed that orange juice tasted bitter. He denied a change in voice or difficulty swallowing. The exam was notable for left-sided ptosis and altered taste to the posterior 1/3^rd tongue to sugar water. CT angiography showed irregularity of the distal left internal carotid artery (ICA) from the C1 segment into the proximal petrosal segment associated with a 3 mm pseudo-aneurysm, concerning for dissection. <h3>Design/Methods:</h3> NA <h3>Results:</h3> The mean annual incidence of spontaneous ICA dissection is 2.9 per 100,000. The classic triad of symptoms is ipsilateral head or neck pain, partial Horner syndrome, and cerebral or retinal ischemic symptoms. Cranial nerve (CN) palsies may occur in more than 10% of patients with extracranial ICA dissections, most commonly involving CN XII, followed by V, VII, IX and X. We discuss a patient with isolated dysgeusia in the posterior 1/3^rd of the tongue with left-sided Horner syndrome in the setting of distal ICA dissection. Clinical presentation is consistent with an isolated glossopharyngeal nerve palsy and Horner syndrome. At the distal cervical level, the glossopharyngeal nerve and sympathetic tract run closely to the ICA and are susceptible to compression by the pseudoaneurysm. There exist only a few reports on loss of taste sensation caused by dissection of ICA. <h3>Conclusions:</h3> This case highlights that posterior ipsilateral dysgeusia can be a manifestation of cervical internal carotid artery dissection and should prompt appropriate evaluation and neuroimaging. <b>Disclosure:</b> Dr. Joseph has nothing to disclose. Dr. Ariza Hutchinson has nothing to disclose. Dr. Shnawa has nothing to disclose. Dr. Sehgal has nothing to disclose.

Teaching NeuroImages: An uncommon cause of carotid artery dissection

Cervical internal carotid artery dissection (CAD), a leading cause of ischemic stroke in young adults, has been rarely associated with Fabry disease (FD).1,2 A 49-year-old man with left acute middle cerebral artery occlusion due to underlying spontaneous CAD received IV thrombolysis and mechanical thrombectomy, achieving complete reperfusion (figure 1).

Bilateral Hypoplasia of the Cervical Internal Carotid Arteries in a Pregnant Patient with Patent Foramen Ovale – A Case Report and Discussion

Introduction: Congenital hypoplasia or aplasia of the internal carotid artery (ICA) is believed to affect less than 0.01% of the population, with fewer than 200 unilateral and 30 bilateral cases reported in the literature. While often asymptomatic, they have been associated with stroke, transient ischemic attack (TIA), and other neurovascular pathologies. Case Report: We describe a 33-year-old 28 weeks pregnant female with a history of patent foramen ovale (PFO) and ischemic stroke in the right middle cerebral artery (MCA) distribution three years prior who experienced new onset transient right upper extremity weakness and numbness. Duplex sonography revealed bilateral hypoplasia of the internal carotid arteries (HICA), confirmed by CT and MR angiography of the head and neck. Discussion: To our knowledge, this is the first reported case of bilateral HICA with concurrent PFO and pregnancy presenting with TIA. All three conditions are associated with stroke and TIA. HICA should be included in the differential diagnosis of neurologic deficit despite its rarity.

Management of Cervical Internal Carotid Artery Stenosis or Occlusion in Tandem Lesion with Acute Ischemic Stroke: Which Is More Appropriate Percutaneous Transluminal Angioplasty or Stent?

Carotid artery stenting (CAS) is the established treatment strategy of the cervical internal carotid artery (cICA) stenosis, but its use for acute tandem lesions remains controversial. We investigated the clinical and procedural outcomes of management of cICA lesions and evaluated the risk factors for complications. Fifty patients who underwent acute mechanical thrombectomy for tandem lesion between January 2014 and June 2022 were included. Treatment of the cICA lesion was classified into the CAS group or the non-CAS group. The risk factors for postoperative ischemic events or symptomatic intracranial hemorrhage (sICH) were analyzed. The CAS group included 36 patients (72%) and the non-CAS group 14 (28%). Postoperative complications were observed in 9 patients (18%). Thromboembolic complications occurred in 4 patients (29%) of the non-CAS group but in 1 patient (3%) of the CAS group. Severe calcification of the cICA (P= 0.04), non-CAS (P= 0.018), and more than 60% residual stenosis (P= 0.016) were significant risk factors associated with thromboembolic complications. sICH occurred in 4 patients (11%) of the CAS group but in none of the non-CAS group. More than 80% stenosis improvement was significantly associated with sICH (P= 0.049). Twenty-nine patients (58%) had a good clinical outcome at 90 days after onset. Acute CAS is effective for the management for cICA tandem lesions during mechanical thrombectomy, but care not to overextend may be important to reduce the risk of sICH. Severe calcification of the cICA may increase the risk of postoperative thromboembolic complications using non-CAS treatment.

Abstract Number ‐ 86: Intracranial Angioplasty via Type II Proatlantal Intersegmental Artery

Introduction A proatlantal intersegmental artery (PIA) is an exceedingly rare primitive anastomosis between the carotid and vertebrobasilar circulations. PIA’s may be accompanied by ipsilateral or bilateral vertebral artery (VA) agenesis and can originate from the cervical internal carotid artery (ICA, type I) or external carotid artery (ECA, type II) before eventually joining the vertebrobasilar system. Several authors have described this anomaly in different clinical scenarios, but to our knowledge, there are no studies documenting intracranial vertebral artery angioplasty through a type II PIA in the setting of a vertebrobasilar stroke. Methods Single case study Results A 62‐year‐old male presented to the ED with slurred speech that began one hour prior to arrival. Computer tomography (CT) of the head revealed a small right posterior acute parietal subdural hematoma, and CT perfusion scan revealed ischemia of the cerebellar hemispheres bilaterally with small areas of core infarction and a moderate‐to‐large surrounding penumbra. Magnetic resonance imaging (MRI) of the brain was positive for bilateral acute ischemic strokes of the cerebellar and pontine arteries. CT angiogram of the head and neck revealed high grade stenosis of the right intracranial VA and narrowing of the left V1, V2, and V3 segments. The proximal left V4 segment was occluded with distal reconstitution. Catheter angiogram of the ICAs and ECAs showed that the patient’s right VA did not originate from the right subclavian artery but instead from the right ECA. The patient was subsequently determined to have a type II PIA with critical stenosis. We proceeded with right VA submaximal angioplasty via the type II PIA. The procedure went without complications and resulted in restoration of vertebrobasilar blood flow, with only moderate stenosis following the submaximal angioplasty. On day 5 postoperatively, the patient reported resolution of his symptoms and was subsequently discharged. Conclusions We presented a case of vertebrobasilar stroke in which the right VA did not originate from the right subclavian artery but instead from the ECA, with a subsequent diagnosis of a type II PIA. The only option for management was to perform the right VA angioplasty via the PIA, which we believe to be the first documented case of intracranial vertebral angioplasty through a type II PIA. This case serves as a reminder of the very rare cases of persistent fetal circulation and the importance of performing a catheter angiogram of both the ICA and ECA. Evaluation of the ECA and subsequent observation of a PIA can completely change both the management and outcomes of the patient. This case underscores the complexity of the intracranial atherosclerotic disease, the beneficial role of endovascular intervention, and the necessity of future studies to identify the optimal treatment methods for vertebrobasilar stroke.

Abstract Number ‐ 121: Flow Diversion Jet: A Dangerous Mechanism in the Flow Diversion Treatment of Giant Intracranial Aneurysms

Introduction We present a patient with a giant vertebrobasilar system aneurysm. This case provides an in‐depth analysis of the pathologic mechanism resulting in catastrophic distal hemorrhage following stent deployment due to the shared effects of normal perfusion pressure breakthrough (NPPB) and the Windkessel phenomenon. The Windkessel phenomenon and NPPB occur before and after treatment of various vascular malformations, respectively. These phenomena are hypothesized to contribute to the loss of cerebrovascular autoregulation. High flow lesions and giant aneurysms reduce blood flow in downstream vessels, causing chronic distal vasodilation to protect against ischemia. Sudden restoration of normal pulsatile flow, following treatment, compromises the integrity of distal vessels leading to potential catastrophic intracerebral hemorrhage. Methods A retrospective review of the patient’s medical record was performed. Results A 60‐year‐old female initially presenting with pulsatile neck mass was found to have dolichoectasia of the right cervical internal carotid artery and two large, irregular, vertebrobasilar aneurysms. Managed conservatively for 10 years before developing gait ataxia, new imaging revealed growth of the now giant, more distal aneurysm. Flow diversion with partial coiling of the aneurysms was pursued. Following deployment, DynaCT demonstrated catastrophic thalamic and midbrain hemorrhage with intraventricular extension. A review of intra‐aneurysmal pressure measurements, angiography, MRI, and neuromonitoring data strongly suggests rupture of multiple deep perforators following the conversion to laminar flow when the flow diverting chain was finalized. This suggests giant aneurysms chronically depress the distal pulse pressure by acting as a Windkessel reservoir. Flow diversion bypasses the reservoir increasing pulse pressure distal to the aneurysm, exceeding autoregulatory capacity, leading to hemorrhage. Conclusions This is the first case in the literature to describe NPPB and the Windkessel phenomenon in the attempt to treat giant aneurysms with flow diversion. Flow diversion bypasses the reservoir, suddenly changing turbulent flow to laminar flow. The resultant dramatic rise in pulse pressure distal to the aneurysm can exceed the autoregulatory mechanisms of small distal vessels such as perforating branches. While demonstrating a poor outcome, awareness of these mechanisms and meticulous intra‐operative blood pressure management may reduce or prevent complications. Further modeling of flow dynamics both before and following treatment of these aneurysms may lead to altered guidelines in the temporality of treatment due to potential catastrophic sequelae.

Functional and Safety Outcomes of Carotid Artery Stenting and Mechanical Thrombectomy for Large Vessel Occlusion Ischemic Stroke With Tandem Lesions

Approximately 10% to 20% of large vessel occlusion (LVO) strokes involve tandem lesions (TLs), defined as concomitant intracranial LVO and stenosis or occlusion of the cervical internal carotid artery. Mechanical thrombectomy (MT) may benefit patients with TLs; however, optimal management and procedural strategy of the cervical lesion remain unclear. To evaluate the association of carotid artery stenting (CAS) vs no stenting and medical management with functional and safety outcomes among patients with TL-LVOs. This cross-sectional study included consecutive patients with acute anterior circulation TLs admitted across 17 stroke centers in the US and Spain between January 1, 2015, and December 31, 2020. Data analysis was performed from August 2021 to February 2022. Inclusion criteria were age of 18 years or older, endovascular therapy for intracranial occlusion, and presence of extracranial internal carotid artery stenosis (>50%) demonstrated on pre-MT computed tomography angiography, magnetic resonance angiography, or digital subtraction angiography. Patients with TLs were divided into CAS vs nonstenting groups. Primary clinical and safety outcomes were 90-day functional independence measured by a modified Rankin Scale (mRS) score of 0 to 2 and symptomatic intracranial hemorrhage (sICH), respectively. Secondary outcomes were successful reperfusion (modified Thrombolysis in Cerebral Infarction score ≥2b), discharge mRS score, ordinal mRS score, and mortality at 90 days. Of 685 patients, 623 (mean [SD] age, 67 [12.2] years; 406 [65.2%] male) were included in the analysis, of whom 363 (58.4%) were in the CAS group and 260 (41.6%) were in the nonstenting group. The CAS group had a lower proportion of patients with atrial fibrillation (38 [10.6%] vs 49 [19.2%], P = .002), a higher proportion of preprocedural degree of cervical stenosis on digital subtraction angiography (90%-99%: 107 [32.2%] vs 42 [20.5%], P < .001) and atherosclerotic disease (296 [82.0%] vs 194 [74.6%], P = .003), a lower median (IQR) National Institutes of Health Stroke Scale score (15 [10-19] vs 17 [13-21], P < .001), and similar rates of intravenous thrombolysis and stroke time metrics when compared with the nonstenting group. After adjustment for confounders, the odds of favorable functional outcome (adjusted odds ratio [aOR], 1.67; 95% CI, 1.20-2.40; P = .007), favorable shift in mRS scores (aOR, 1.46; 95% CI, 1.02-2.10; P = .04), and successful reperfusion (aOR, 1.70; 95% CI, 1.02-3.60; P = .002) were significantly higher for the CAS group compared with the nonstenting group. Both groups had similar odds of sICH (aOR, 0.90; 95% CI, 0.46-2.40; P = .87) and 90-day mortality (aOR, 0.78; 95% CI, 0.50-1.20; P = .27). No heterogeneity was noted for 90-day functional outcome and sICH in prespecified subgroups. In this multicenter, international cross-sectional study, CAS of the cervical lesion during MT was associated with improvement in functional outcomes and reperfusion rates without an increased risk of sICH and mortality in patients with TLs.

Abstract Number ‐ 172: First‐in‐Human Experience: Route 92 Medical 132 cm FreeClimb 88 Catheter for Anterior Circulation LVOs

Introduction Direct aspiration thrombectomy of proximal anterior circulation large vessel occlusions (LVOs) with super‐bore catheters (SBCs, 0.088” ID) may result in improved first pass success, though their consistent delivery to the target occlusion remains challenging. We report the first‐in‐human experience with a novel full‐length 132 cm 0.088” ID FreeClimb ® 88 catheter (Route 92 Medical, San Mateo, CA, currently approved for neurovascular access), and its customized Tenzing ® 8 delivery catheter, for anterior circulation LVO acute stroke patients. Methods We performed a retrospective review of thrombectomy cases for proximal anterior circulation large vessel occlusions performed at three stroke centers from May 2022 through August 2022. All patients were treated using the Route 92 Medical 8F Base Camp® guide catheter, FreeClimb ® 88 catheter and Tenzing ® 8 delivery catheter in an off‐label fashion. Results Ten consecutive acute stroke patients with anterior circulation LVOs were treated. The median age was 71 (45‐91) and 6 were female (60%). The median presenting NIHSS score and ASPECT score were 17 (8‐24) and 9 (6‐10), respectively. LVO locations were as follows: two right carotid termini, three right M1 middle cerebral arteries, and five left M1 middle cerebral arteries. Three patients also had tandem occlusion/near‐occlusion of the respective cervical internal carotid artery. The FC88 catheter was delivered to the target occlusion with 100% success. The median time from groin puncture to catheter delivery to the target occlusion was 14 minutes (7‐35). First pass complete reperfusion (modified Thrombolysis in Cerebral Infarction score, mTICI, of 3) was achieved in 9/10 (90%) patients (self‐adjudicated). Adjunctive therapy for a residual M2 occlusion was utilized in 1/10 patients. There were no adverse events or post‐procedural symptomatic hemorrhages. Conclusions Our first‐in‐human experience with a novel 132 cm full‐length super‐bore catheter (Route 92 FreeClimb ® 88 catheter) and its customized catheter delivery device (Tenzing ® 8) for aspiration thrombectomy of proximal anterior circulation large vessel occlusions demonstrated 100% successful delivery to the target occlusion, with TICI 3 first pass reperfusion achieved in 90% of patients.

Abstract Number ‐ 239: Subcortical Infarcts in Patients with Nonstenotic Cervical Atherosclerotic Disease

Introduction Prior studies have elucidated a relationship between nonstenotic plaque in patients with cryptogenic embolic (cortical) infarcts, however it is unclear if nonstenotic carotid plaque is relevant in subcortical infarct patterns. Methods A nested cohort of consecutive patients with anterior, unilateral, subcortical infarcts without an identifiable embolic source were identified from a prospective stroke registry (September 2019 ‐ June 2021). Patients with extracranial stenosis &gt;50% were excluded. Patients with computed tomography angiography were included and comparisons made according to infarct pattern being lacunar (single lesion &lt; 1.5cm on computed tomography [CT] or &lt; 2.0cm on diffusion weighted imaging [DWI]) versus cryptogenic (≥ 1.5cm on CT or ≥ 2.0cm on DWI, or scattered subcortical lesions). Prevalence estimates for cervical internal carotid artery (ICA) plaque presence were estimated with 95% confidence intervals (CI), and differences in plaque thickness and features were compared between sides. Results Of the 1684 who were screened, 141 met inclusion criteria (n = 80 due to small vessel disease, n = 61 cryptogenic). The median age was 66y (interquartile range, IQR 58–73) and National Institutes of Health Stroke Scale score was 3 (IQR 1–5). There was a higher probability of finding excess plaque ipsilateral to the stroke (41.1%, 95%CI 33.3‐49.3%) than finding excess contralateral plaque (29.1%, 95%CI 22.2‐37.1%; p = 0.03), but this was driven by patients with cryptogenic infarcts (excess ipsilateral vs. contralateral plaque frequency of 49.2% vs. 14.8%, p&lt; 0.001) and not lacunar disease (35.0% vs. 40.0%, p = 0.51). Conclusions The probability of finding ipsilateral, nonstenotic carotid plaque in patients with subcortical cryptogenic strokes exceeds the probability of contralateral plaque and is driven by larger subcortical infarcts, classically defined as being cryptogenic. Approximately 1 in 3 unilateral anterior subcortical infarcts may be due to nonstenotic ICA plaque.