Middle meningeal artery embolization for chronic subdural hematoma: A single-center experience and predictive modeling of outcomes.

BACKGROUND: Remarkable interest is rising around middle meningeal artery embolization (MMAE) as an emerging alternative therapy for chronic subdural hematoma (cSDH). The study aims to highlight a large center experience and the variables associated with treatment failure and build experimental machine learning (ML) models for outcome prediction. MATERIAL AND METHODS: A 2-year experience in MMAE for managing patients with chronic subdural hematoma was analyzed. Descriptive statistical analysis was conducted using imaging and clinical features of the patients and cSDH, which were subsequently used to build predictive models for the procedure outcome. The modeling evaluation metrics were the area under the ROC curve and F1-score. RESULTS: A total of 100 cSDH of 76 patients who underwent MMAE were included with an average follow-up of 6 months. The intervention had a per procedure success rate of 92%. Thrombocytopenia had a highly significant association with treatment failure. Two patients suffered a complication related to the procedure. The best performing machine learning models in predicting MMAE failure achieved an ROC-AUC of 70%, and an F1-score of 67%, including all patients with or without surgical intervention prior to embolization, and an ROC-AUC of 82% and an F1-score of 69% when only patients who underwent upfront MMAE were included. CONCLUSION: MMAE is a safe and minimally invasive procedure with great potential in transforming the management of cSDH and reducing the risk of surgical complications in selected patients. An ML approach with larger sample size might help better predict outcomes and highlight important predictors following MMAE in patients with cSDH.

Patient-reported outcome measures in cerebrovascular neurosurgery.

OBJECTIVE: The object of this study was to describe the use of patient-reported outcome measures (PROMs) in cerebrovascular neurosurgery and to outline a framework for incorporating them into future cerebrovascular research. METHODS: Following the standardized PRISMA guidelines, the authors performed a search of the PubMed and Embase databases in February 2023 using filters to investigate six specific cerebrovascular pathologies/procedures: subarachnoid hemorrhage (SAH), intracranial hemorrhage, ischemic stroke, arteriovenous malformation, chronic subdural hematoma, and carotid artery stenosis. PROMs in the identified articles were distinguished and classified as generic, symptom specific, or disease specific. RESULTS: A total of 259 studies including 51 PROMs were eligible for inclusion in the review. Most of the PROMs were generic or symptom specific. Only 5 PROMs were disease specific, and all of these pertained to stroke or SAH. CONCLUSIONS: There are only a limited number of disease-specific PROMs available for cerebrovascular pathologies and outcomes. Further validation of existing measures in independent cohorts, expanded incorporation of disease-specific PROMs in prospective trials, and the development of new PROMs specific to cerebrovascular conditions are critical to a better understanding of the impact of cerebrovascular diseases and novel therapies on patient lives.

Clot composition and recanalization outcomes in mechanical thrombectomy.

BACKGROUND: Mechanical thrombectomy (MT) has become standard for large vessel occlusions, but rates of complete recanalization are suboptimal. Previous reports correlated radiographic signs with clot composition and a better response to specific techniques. Therefore, understanding clot composition may allow improved outcomes. METHODS: Clinical, imaging, and clot data from patients enrolled in the STRIP Registry from September 2016 to September 2020 were analyzed. Samples were fixed in 10% phosphate-buffered formalin and stained with hematoxylin-eosin and Martius Scarlett Blue. Percent composition, richness, and gross appearance were evaluated. Outcome measures included the rate of first-pass effect (FPE, modified Thrombolysis in Cerebral Infarction 2c/3) and the number of passes. RESULTS: A total of 1430 patients of mean±SD age 68.4±13.5 years (median (IQR) baseline National Institutes of Health Stroke Scale score 17.2 (10.5-23), IV-tPA use 36%, stent-retrievers (SR) 27%, contact aspiration (CA) 27%, combined SR+CA 43%) were included. The median (IQR) number of passes was 1 (1-2). FPE was achieved in 39.3% of the cases. There was no association between percent histological composition or clot richness and FPE in the overall population. However, the combined technique resulted in lower FPE rates for red blood cell (RBC)-rich (P<0.0001), platelet-rich (P=0.003), and mixed (P<0.0001) clots. Fibrin-rich and platelet-rich clots required a higher number of passes than RBC-rich and mixed clots (median 2 and 1.5 vs 1, respectively; P=0.02). CA showed a trend towards a higher number of passes with fibrin-rich clots (2 vs 1; P=0.12). By gross appearance, mixed/heterogeneous clots had lower FPE rates than red and white clots. CONCLUSIONS: Despite the lack of correlation between clot histology and FPE, our study adds to the growing evidence supporting the notion that clot composition influences recanalization treatment strategy outcomes.

Endovascular revascularization of chronically occluded common carotid artery for symptomatic cerebral hypoperfusion.

Endovascular recanalization is increasingly being utilized in symptomatic patients with chronically occluded carotid arteries.1 In carefully selected patients, endovascular recanalization has shown to lower the risk of ischemic events when compared to medical management alone.1 However, successful endovascular revascularization is technically challenging and not without risk.1, 2 In this video, we demonstrate a case of a 64-year-old woman who presented with recurrent transient ischemic attacks. On imaging she was found to have a chronic total occlusion of the common carotid artery from the arch. After obtaining informed consent, the patient underwent a successful endovascular recanalization and stenting of a chronically occluded left common carotid artery with aid from an intravascular guided re-entry catheter. Post operatively the patient developed a neck hematoma which improved and she returned to her neurological baseline. She reported no further symptoms on her three month follow up.

Vagus nerve stimulation using an endovascular electrode array.

Objective. Vagus nerve stimulation (VNS), which involves a surgical procedure to place electrodes directly on the vagus nerve (VN), is approved clinically for the treatment of epilepsy, depression, and to facilitate rehabilitation in stroke. VNS at surgically implanted electrodes is often limited by activation of motor nerve fibers near and within the VN that cause neck muscle contraction. In this study we investigated endovascular VNS that may allow activation of the VN at locations where the motor nerve fibers are not localized.Approach. We used endovascular electrodes within the nearby internal jugular vein (IJV) to electrically stimulate the VN while recording VN compound action potentials (CAPs) and neck muscle motor evoked potentials (MEPs) in an acute intraoperative swine experiment.Main Results. We show that the stimulation electrode position within the IJV is critical for efficient activation of the VN. We also demonstrate use of fluoroscopy (cone beam CT mode) and ultrasound to determine the position of the endovascular stimulation electrode with respect to the VN and IJV. At the most effective endovascular stimulation locations tested, thresholds for VN activation were several times higher than direct stimulation of the nerve using a cuff electrode; however, this work demonstrates the feasibility of VNS with endovascular electrodes and provides tools to optimize endovascular electrode positions for VNS.Significance. This work lays the foundation to develop endovascular VNS strategies to stimulate at VN locations that would be otherwise too invasive and at VN locations where structures such as motor nerve fibers do not exist.

Carotid Artery Tortuosity and Internal Carotid Artery Plaque Composition.

BACKGROUND: 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). MATERIAL AND METHODS: A retrospective review was completed of 102 patients 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. RESULTS: The mean age of included patients was 73.5 years (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 a retrojugular 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 a LRNC 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. CONCLUSION: ICA tortuosity is not associated with carotid artery plaque composition, and likely does not play a role in the development of high-risk plaques.

Intraplaque hemorrhage on magnetic resonance angiography: How often do signal abnormalities persist on follow-up imaging?

BACKGROUND AND PURPOSE: Intraplaque hemorrhage (IPH) in carotid atherosclerosis demonstrates increased signal on magnetic resonance angiography images. Little remains known about how this signal changes on subsequent examinations. MATERIALS AND METHODS: A retrospective observational study was completed of patients that had IPH on a neck MRA between 1/1/2016 and 3/25/2021, defined as ≥ 200 % signal intensity of the sternocleidomastoid muscle on MPRAGE images. Examinations were excluded if the patients had undergone carotid endarterectomy between examinations or had poor quality imaging. IPH volumes were calculated by manually outlining IPH components. Up to 2 subsequent MRAs, if available, were assessed for both the presence and volume of IPH. RESULTS: 102 patients were included, of which 90 (86.5 %) were male. IPH was on the right in 48 patients (average volume = 174.0 mm3), and on the left in 70 patients (average volume 186.9 mm3). 22 had at least one follow-up (average 444.7 days between exams), and 6 had two follow-up MRAs (average 489.5 days between exams). On the first follow-up, 19 (86.4 %) plaques had persistent hyperintense signal in the region of IPH. The second follow-up showed persistent signal in 5/6 plaques (88.3 %). Combined volume of IPH from right and left carotid arteries did not significantly decrease on the first follow-up exam (p = 0.08). CONCLUSIONS: IPH usually retains hyperintense signal on follow-up MRAs, possibly representing recurrent hemorrhage or degraded blood products.

Use of intravascular optical coherence tomography to confirm the diagnosis of a carotid web in a patient with recurrent ipsilateral embolic strokes and evaluate the response to stenting.

A Carotid web (CaW) is defined as a focal shelf-like projection of non-atheromatous, fibrous tissue along the posterior wall of the carotid bulb. CaW are rare and commonly overlooked lesions increasingly recognized as a cause of stroke in otherwise healthy patients. Intravascular imaging modalities such as intravascular ultrasound and optical coherence tomography (OCT) have been proposed as an adjunct to digital subtraction angiography for the evaluation of CaW. However, the use of OCT in CaW has yet to be described. This report investigated the utility of OCT as an adjunct imaging modality in the evaluation of CaW morphology in a young patient with recurrent ischemic strokes.

Evaluation of an in vivo preclinical model for human middle meningeal artery embolization using the posterior intercostal artery of the swine.

BACKGROUND: Embolization of the middle meningeal artery (MMA) is a promising minimally invasive technique that is gaining traction in the treatment of chronic subdural hematoma. Unfortunately, the human meninges and associated arteries are significantly larger than those of conventional laboratory animals, making the development of a clinically relevant animal model for testing of embolization agents elusive. OBJECTIVE: To introduce the posterior intercostal artery (PIA) model in swine and provide anatomical, angiographic, histological, and procedural data to validate its relevance in modeling the human MMA. METHODS: In human cadaveric specimens, 3D angiograms of the internal maxillary arteries (n=6) were obtained and the dura with MMA were harvested and histologically processed. Angiographic and histologic data of the human MMA were compared with the swine PIA (three animals). Then, embolization of the PIA (n=48 arteries) was conducted with liquid embolization agent (Onyx, Medtronic), and angiographic and histological results were assessed acutely (four animals) and after 30 days (two animals). RESULTS: The human MMA has equivalent diameter, length, branching pattern, 3D trajectory, and wall structure to those of swine PIAs. Each swine has 12 to 14 PIAs (6-7 per side) suitable for acute or chronic embolization, which can be performed with high fidelity using the same devices, agents, and techniques currently used to embolize the MMA. The arterial wall structure and the acute and chronic histological findings in PIAs after embolization are comparable to those of humans. CONCLUSIONS: This PIA model in swine could be used for research and development; objective benchmarking of agents, devices, and techniques; and in the training of neurointerventionalists.

Vessel wall imaging features of Moyamoya disease in a North American population: patterns of negative remodelling, contrast enhancement, wall thickening, and stenosis.

BACKGROUND: This study characterized vessel wall imaging (VWI) features of Moyamoya disease (MMD) in a predominantly adult population at a North American center. METHODS: Consecutive patients with VWI were included. Twelve arterial segments were analyzed for wall thickening, degree and pattern of contrast enhancement, and remodeling. RESULTS: Overall, 286 segments were evaluated in 24 patients (mean age = 36.0 years [range = 1-58]). Of 172 affected segments, 163 (95%) demonstrated negative remodeling. Complete vessel wall obliteration was most frequent in the proximal M1 (17/48, 35%). Affected segments enhanced in 72/172 (42%) (n = 15 for grade II; n = 54 for concentric and n = 18 for eccentric); 20 of 24 (83%) patients had at least one enhancing segment. Both enhancing and non-enhancing segments were present in 19/20 (95%) patients. Vessel wall enhancement was most common in the proximal segments and correlated to the degree of stenosis (p < 0.001), and outer wall diameter (p < 0.001), but not disease duration (p = 0.922) or Suzuki score (p = 0.477). Wall thickening was present in 82/172 (48%) affected segments and was associated with contrast enhancement (p < 0.001), degree of stenosis (p < 0.001), and smaller outer wall diameter (p = 0.004). CONCLUSION: This study presents VWI findings in North American patients with MMD. Negative remodeling was the most common finding. Most patients had both enhancing and non-enhancing abnormal segments. Vessel wall enhancement was most common in proximal segments, variable in pattern or degree and was correlated to the degree of stenosis and smaller outer wall diameter.

Surgical Techniques and Nuances for Superior Cervical Ganglionectomy and Decentralization in Rats.

The sympathetic nervous system has been implicated in various physiological and pathological processes, including regulation of homeostatic functions, maintenance of the circadian rhythms, and neuronal disruption and recovery after injury. Of special interest is focus on the role of the superior cervical ganglion (SCG) in regulating the daily changes in pineal function. Removal of the superior cervical ganglion (SCGx) and decentralization have served as valuable microsurgical models to investigate the effects of surgical denervation on this gland or organ. In this chapter, we offer information about methodologies for performing SCGx along with decentralization and denervation procedures, including details about recommended equipment as well as tips that can improve these techniques.

The "Michelangelo Code": The Quest for Universal Truth.

Michelangelo's unparalleled frescoes in the Sistine Chapel have been traditionally construed to represent the traditional, Roman Catholic interpretation of the Seven Days of Creation in the Book of Genesis and the Last Judgement. Indeed, in September 2018, Pope Francis I offered a benediction for the Vatican's art treasures and for "those who contributed to the Church's history through art." A number of studies have suggested that Michelangelo concealed anatomic information about the human brain in his renderings of God and biblical prophets and saints. Was the anatomic content of these images purposeful or coincidental? Was the anatomy intentionally concealed? Is there a common pattern with symbolic connotations in the anatomic representations? Was Michelangelo sending an encoded message? In this study, we analyze the imagery in the Sistine frescoes in light of the literature surrounding Michelangelo's artistry with a particular interest in the relationship between the certain purported anatomic depictions and details demonstrable using scientific and anatomic techniques available during the High Renaissance.

Bibliometric Trends in Open Surgical and Endovascular Cerebrovascular Research.

The last decade has witnessed a major expansion in endovascular interventions concurrent with a contraction of open neurovascular surgeries. Whether research efforts have also shifted from open to endovascular neurosurgery is an effect that has not been explored extensively. Understanding the bibliometric trend is important for researchers, funding agencies, and publishing journals. The aim of this review is to explore this potential shift. We compared the bibliometrics of open cerebrovascular and endovascular research articles published in two neurosurgical journals (Journal of Neurosurgery, Neurosurgery) and two neuroradiological journals (Journal of Neurointerventional Surgery, American Journal of Neuroradiology). Data were collected between September 26, 2021, and October 18, 2021. Articles published in 2011, 2013, 2015, 2017, and 2019 from the journals were screened. Neurovascular articles were classified into open surgical, endovascular, or mixed. Bibliometric parameters were collected via SCOPUS and journals' websites. A total of 8,018 articles were screened, of which 1,551 were included (16.2% open, 62.2% endovascular, 21.5% mixed). Most articles were related to aneurysms (76%). Open-access status correlated with increased citations (p<0.001) and Altmetric (p<0.001), which measures online activity. Comparing 2011 and 2019, the article distribution (open/endovascular/mixed) has changed significantly (χ2 test, p=0.002), with open articles dropping from 23.6% (68/288) to 12.9% (44/342) and endovascular articles rising from 56.6% (163/288) to 65.8% (225/342). Using the Kruskal-Wallis test, the citation distribution is different across the three groups in 2019 (p<0.001), favoring endovascular articles, but not in the other years. Our study suggests a trend of diminishing open neurovascular research output and increasing endovascular research output, in terms of both the number of articles and the citations. More time for citation accumulation may be required to verify this trend.

Change of Heart: The Underexplored Role of Plaque Hemorrhage in the Evaluation of Stroke of Undetermined Etiology.

In the evaluation of embolic strokes of undetermined source, great emphasis is often placed on cardiovascular disease, namely on atrial fibrillation. Other pathophysiologic mechanisms, however, may also be involved. Carotid artery intraplaque hemorrhage (IPH)-the presence of blood components within an atheromatous plaque-has become increasingly recognized as a possible etiologic mechanism in some cryptogenic strokes. IPH is a marker of plaque instability and is associated with ipsilateral neurologic ischemic events, even in nonstenotic carotid plaques. As recognition of carotid IPH as an etiology of embolic strokes has grown, so too has the complexity with which such patients are evaluated and treated, particularly because overlaps exist in the risk factors for atrial fibrillation and IPH. In this article, we review what is currently known about carotid IPH and how this clinical entity should be approached in the context of the evaluation of embolic strokes of undetermined source.

Intra-procedural cerebral sinus thrombosis during endovascular treatment of idiopathic intracranial hypertension.

Stenting of the intracranial venous sinuses has shown promising results in patients who are refractory to medical treatment of idiopathic intracranial hypertension (IIH). Among the reported complications associated with this procedure, in-stent thrombosis is an unreported one. We present a case of cerebral sinus thrombosis during endovascular treatment of IIH. A 33-year-old man with multiple comorbidities was presented with non-specific vision changes and headaches. Initial workup revealed a diagnosis of idiopathic intracranial hypertension which was treated medically but with no improvement. Therefore, cerebral sinus stenting was pursued. During the procedure, an in-stent thrombus was identified which was retrieved mechanically and was sent for histological and immunohistochemical evaluation. The retrieved thrombus was predominantly composed of RBCs (57.8%) followed by fibrin (30.78%), platelet (6.4%), and WBCs (5.95%), with high expression of CitH3 (neutrophil extra cellular traps specific marker) (10.9%), and CD66 (11.35%).

Carotid artery endarterectomy in patients with symptomatic non-stenotic carotid artery disease.

OBJECT: We sought to determine the safety and efficacy in secondary stroke prevention of carotid endarterectomy (CEA) in patients with symptomatic non-stenotic carotid artery disease (SyNC). METHODS: This was a single-centre retrospective case series. All patients who underwent CEA for unilateral anterior circulation cerebrovascular events with ipsilateral <50% carotid stenosis from 2002 to 2020 were included. Imaging hallmarks including the degree of luminal stenosis and the presence of various vulnerable plaque characteristics (eg, intraplaque haemorrhage (IPH) on MR angiography, ulceration or low-density plaque on CT angiography) were assessed. The presence of vulnerable plaque characteristics was compared between arteries ipsilateral to the ischaemic event and contralateral arteries. The prevalence of perioperative/intraoperative complications, as well as recurrent ischaemic events at follow-up was determined. RESULTS: Thirty-two patients were included in the analysis, of which 25.0% were female. Carotid arteries ipsilateral to an ischaemic event had a significantly higher prevalence of IPH when compared with contralateral arteries (80.0% vs 0.0%; p<0.001). There were no intraoperative complications. One patient (3.1%) developed symptoms of transient ipsilateral ischaemia 1 day following CEA which resolved without treatment. In a median follow-up of 18.0 months (IQR 5.0-36.0), only one patient (3.1%) experienced a transient neurologic deficit with complete resolution (annualised rate of recurrent stroke after CEA of 1.5% for a total follow-up of 788 patient-months following CEA). All other patients (31/32, 96.9%) were free of recurrent ischaemic events. CONCLUSION: CEA appears to be safe and well-tolerated in patients with SyNC. Additional studies with larger cohorts and longer follow-up intervals are needed in order to determine the role of CEA in this patient population.

Histological composition of retrieved emboli in acute ischemic stroke is independent of pre-thrombectomy alteplase use.

BACKGROUND AND PURPOSE: Given recent evidence suggesting the clot composition may be associated with revascularization outcomes and stroke etiology, clot composition research has been a topic of growing interest. It is currently unclear what effect, if any, pre-thrombectomy thrombolysis has on clot composition. Understanding this association is important as it is a potential confounding variable in clot composition research. We retrospectively evaluated the composition of retrieved clots from ischemic stroke patients who did and did not receive pre-treatment tPA to study the effect of tPA on clot composition. MATERIALS AND METHODS: Consecutive patients enrolled in the Stroke Thromboembolism Registry of Imaging and Pathology (STRIP) were included in this study. All patients underwent mechanical thrombectomy and retrieved clots were sent to a central core lab for processing. Histological analysis was performed using Martius Scarlett Blue (MSB) staining and area of the clot was also measured on the gross photos. Student's t test was used for continuous variables and chi-squared test for categorical variables. RESULTS: A total of 1430 patients were included in this study. Mean age was 68.4±13.5 years. Overall rate of TICI 2c/3 was 67%. A total of 517 patients received tPA (36%) and 913 patients did not (64%). Mean RBC density for the tPA group was 42.97±22.62% compared to 42.80±23.18% for the non-tPA group (P=0.89). Mean WBC density for the tPA group was 3.74±2.60% compared to 3.42±2.21% for the non-tPA group (P=0.012). Mean fibrin density for the tPA group was 26.52±15.81% compared to 26.53±15.34% for the non-tPA group (P=0.98). Mean platelet density for the tPA group was 26.22±18.60% compared to 26.55±19.47% for the non-tPA group (P=0.75). tPA group also had significantly smaller clot area compared to non-tPA group. CONCLUSIONS: Our study 1430 retrieved emboli and ischemic stroke patients shows no interaction between tPA administration and clot composition. These findings suggest that tPA does not result in any histological changes in clot composition.