Mathematical modeling in assessing the risk of restenosis after carotid endarterectomy.

Carotid endarterectomy is the main way to combat atherosclerosis of the carotid arteries, which disrupts cerebral circulation. The generally accepted marker of atherogenesis risk are hemodynamic indices associated with near-wall shear stress. The purpose of the work is to conduct a comparative analysis of hemodynamic indices in various carotid bifurcation models. The influence of a virtual change in the geometric shape of the model in order to optimize hemodynamic indices is also being studied. On the basis of computed angiography data, carotid bifurcation models are constructed, in which critical zones of hemodynamic indices are built using computational fluid dynamics. A comparative analysis of the critical zones for different classes of models is carried out. Comparison of averaged indices for critical zones between 'normal' and post-operative groups gave more than 5-x worse results for the latter. The same results for the near-bifurcation parts of the zones give a 25% better result for postoperative models. Virtual 'removal' of insignificant plaques leads to a deterioration of the indices of up to 40% in the places of the plaque's former location. The described method makes it possible to build the indices critical zones and compare them for various types of models. A technique for virtual changing the shape of a vessel (virtual surgery) is proposed. The novelty of the approach lies in the use for comparative analysis both real vessel models and hypothetical 'improved' virtual ones, as well in the proposed division of post-operative model's critical zones into subzones of different genesis.

Clinical Significance of Carotid Endarterectomy and Carotid Artery Stenting in Older Patients Over 80.

As the average life expectancy increases, neurosurgeons are likely to encounter patients aged 80 years and above with carotid stenosis; however, whether old age affects clinical post-treatment outcomes of carotid endarterectomy (CEA) or carotid artery stenting (CAS) remains inconclusive. Thus, this study aimed to evaluate the outcomes following CEA or CAS in patients aged 80 years and above. This study included older over 80 years (n = 34) and younger patients (<80 years; n = 222) who underwent CEA or CAS between 2012 and 2022. All of them were followed up for a mean of 55 months. All-cause mortality, the incidence of vascular events, ability to perform daily activities, and nursing home admission rates were assessed. During follow-up periods, 34 patients (13.3%) died due to coronary artery disease, malignancy, and pneumonia, and the incidence was significantly higher in the elderly group than in the younger group (P = 0.03; HR, 3.01; 95% CI, 1.53-5.56). The incidence of vascular events did not differ between the older group (29.5%) and the younger group (26.9%, P = 0.58); however, the incidence was significantly higher in patients with high-intensity plaques than in those without that (P = 0.008; HR, 2.83, 95%CI, 1.27-4.87). The decline in the ability to perform daily activities and increased nursing home admission rates were high in elderly patients (P < 0.01). Although the mortality rate was higher in the elderly group, subsequent vascular events were comparable to that in the younger group. The results suggest that CEA and CAS are safe and useful treatments for carotid stenosis in older patients, especially to prevent ipsilateral ischemic stroke.

Endovascular treatment of acute atherothrombotic internal carotid artery occlusion associated with persistent primitive hypoglossal artery.

Persistent primitive hypoglossal artery is a relatively rare anatomical variation and a type of persistent carotid-basilar anastomosis. Acute internal carotid artery occlusion associated with persistent primitive hypoglossal artery is rare, and atherothrombotic occlusion is extremely rare. We present a case of acute atherothrombotic internal carotid artery occlusion associated with persistent primitive hypoglossal artery that was successfully treated by endovascular treatment. A 70-year-old male with a history of left internal carotid artery stenosis was transferred to our hospital by ambulance because of abnormal behaviors and aphasia. He was diagnosed with cerebral infarction and left internal carotid artery occlusion. Left carotid angiography revealed the persistent primitive hypoglossal artery arising from the cervical internal carotid artery and complete internal carotid artery occlusion distal to the origin of the persistent primitive hypoglossal artery. Therefore, we performed endovascular treatment. Mechanical thrombectomy was performed under minimal flow arrest with consideration of brain ischemia causing coma. After additional balloon angioplasty, recanalization was achieved, and the patient's symptoms improved. During the 1.5-year follow-up period, no recurrence or restenosis was observed. This report provides evidence that atherosclerotic internal carotid artery stenosis associated with persistent primitive hypoglossal artery can occur even distal to the origin of the persistent primitive hypoglossal artery and that the lesion may become acutely occluded, leading to acute stroke. Endovascular treatment considering brain ischemia was effective in this case.

Endothelialization of PTFE-covered stents for aneurysms and arteriovenous fistulas created in canine carotid arteries.

To investigate the endothelialization of covered and bare stents deployed in the canine carotid arteries and subclavian arteries for treating experimental aneurysms and arteriovenous fistulas, twenty aneurysms were created in 10 dogs, and 20 fistulas in another 10 dogs. The Willis balloon-expandable covered stent and a self-expandable covered stent were used to treat these lesions, and a self-expandable bare stent was deployed in the subclavian artery for comparison. Followed up for up to 12 months, the gross observation, pathological staining, and scanning electronic microscopic data were analyzed. Two weeks after creation of animal model, thirty self-expandable covered stents and ten balloon-expandable covered stents were deployed. Fifteen bare stents were deployed within the left subclavian arteries. Twenty days after stenting, the aneurysm significantly shrank. At 6 months, the thrombi within the aneurysm cavity were organized. Three to 12 months later, most covered and bare stents were covered by a thin transparent or white layer of endothelial intima. Layers of intima or pseudomembrane were formed on the stent 20-40 days after stent deployment. Over three months, the pseudomembrane became organized, thinner, and merged into the vascular wall. Under scanning electronic microscopy, the surface of covered and bare stents had only deposition of collagen fibers and rare endothelial cells 20-40 days after stenting. From three to ten months, the endothelial cells on the internal surface of stent became mature, with spindle, stripe-like or quasi round morphology along the blood flow direction. Over time, the endothelial cells became mature. In conclusion, three months after deployment in canines' arteries, the self-expandable bare and covered stents have mostly been covered by endothelial cells which become maturer over time, whereas the balloon-expandable covered stents do not have complete coverage of endothelial cells at three months, especially for protruding stent struts and areas. Over time, the endothelialization will become mature.

Carotid Near-Occlusion: Surgical or Conservative Management? Retrospective Multicenter Study.

BACKGROUND: Carotid near-occlusion (CNO) represents an anatomical-functional condition characterized by severe (more than 90%) internal carotid artery stenosis which can lead to a distal lumen diameter greater or less than 2 mm. CNO can be divided into a less severe subgroup (without lumen full collapse: diameter >2 mm) and a more severe subgroup (with lumen full collapse: diameter <2 mm). The decision for revascularization is still highly debated in Literature. The aim of the present multicenter retrospective study is to analyze the incidence of perioperative (30 days) and follow-up complications in 2 groups of patients with or without distal internal carotid lumen full collapse. METHODS: Between January 2011 and March 2023, in 5 Vascular Surgery Units, 67 patients (49 male, 73% and 18 females, 27%) with CNO underwent carotid endarterectomy: 28 (41.7%) with lumen diameter <2 mm and 39 (58.3%) with diameter >2 mm. 19 patients were symptomatic and 48 asymptomatic. The outcomes considered for comparative analysis were: perioperative neurological and cardiac complications, carotid restenosis or occlusion at follow-up. Both groups were homogeneous in terms of risk factors, morphological features and pharmacological treatments. RESULTS: In the group with lumen <2 mm, 3 perioperative major events (10.7%) occurred (1 ischemic stroke, 1 hemorrhagic stroke, 1 myocardial infarction) and 2 (7.1%) at follow-up (average 11 ± 14.5 months; 1 asymptomatic carotid occlusion, 1 hemodynamic restenosis treated with stenting). No event was recorded in the group with lumen >2 mm. CONCLUSIONS: According to our results CNO patients show different complication risk according to the presence or not of distal lumen collapse. The later seems to play a significant role in perioperative and follow-up complication rate. These results therefore support a surgical treatment only in patients with CNO without lumen full collapse.

Comparison of Perioperative Safety of Carotid Artery Stenting and Endarterectomy in the Treatment of Carotid Artery Stenosis: A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Current management guidelines for the treatment of carotid stenosis are controversial. We performed this meta-analysis to evaluate the perioperative safety of carotid artery stenting (CAS) and endarterectomy. METHODS: We systematically searched EMBASE, PubMed, Web of Science, and the Cochrane Library from inception to November 10, 2022, for randomized controlled trials that compared CAS with carotid endarterectomy (CEA) among patients with carotid stenosis. The analyzed outcomes mainly included stroke, death, myocardial infarction (MI), cranial nerve palsy, the cumulative incidence of mortality, stroke, or MI and the cumulative incidence of death or stroke in the perioperative periods. The risk ratio (RR) and 95% confidence interval (95% CI) were calculated and pooled. Subgroup analyses were based on whether patients were symptomatic or asymptomatic. We assessed the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation framework. RESULTS: Seventeen randomized controlled trials with 12,277 participants (6514 and 5763 in the CAS and CEA groups, respectively) were included. Pooled analysis demonstrated that compared with CEA, CAS was associated with decreased risks of perioperative MI (RR = 0.47, 95% CI = 0.29∼0.77) and perioperative cranial nerve palsy (RR = 0.02, 95% CI = 0.01∼0.06) but higher risks of perioperative stroke (RR = 1.48, 95% CI = 1.18∼1.87) and cumulative incidence of death or stroke (RR = 1.52, 95% CI = 1.20∼1.93). CONCLUSIONS: The perioperative safety was equivalent between CAS and CEA. However, CEA may be preferred when considering both procedural safety and long-term efficacy in preventing recurrent stroke.

Alamandine attenuates oxidative stress in the right carotid following transverse aortic constriction in mice.

OBJECTIVE: Pressure overload can result in significant changes to the structure of blood vessels, a process known as vascular remodeling. High levels of tension can cause vascular inflammation, fibrosis, and structural alterations to the vascular wall. Prior research from our team has demonstrated that the oral administration of alamandine can promote vasculoprotective effects in mice aorta that have undergone transverse aortic constriction (TAC). Furthermore, changes in local hemodynamics can affect the right and left carotid arteries differently after TAC. Thus, in this study, we aimed to assess the effects of alamandine treatment on right carotid remodeling and the expression of oxidative stress-related substances induced by TAC. METHODS AND RESULTS: Male C57BL/6 mice were categorized into three groups: Sham, TAC, and TAC treated with alamandine (TAC+ALA). Alamandine treatment was administered orally by gavage (30 µg/kg/day), starting three days before the surgery, and continuing for a period of fourteen days. Morphometric analysis of hematoxylin and eosin-stained sections revealed that TAC induced hypertrophic and positive remodeling in the right carotid artery. Picrosirius Red staining also demonstrated an increase in total collagen deposition in the right carotid artery due to TAC-induced vascular changes. Alamandine treatment effectively prevented the increase in reactive oxygen species production and depletion of nitric oxide levels, which were induced by TAC. Finally, alamandine treatment was also shown to prevent the increased expression of nuclear factor erythroid 2-related factor 2 and 3-nitrotyrosine that were induced by TAC. CONCLUSION: Our results suggest that alamandine can effectively attenuate pathophysiological stress in the right carotid artery of animals subjected to TAC.

Accelerated Measurement of Carotid Plaque Volume Using Artificial Intelligence Enhanced 3D Ultrasound.

BACKGROUND: Carotid plaque volume (CPV) can be measured by 3D ultrasound and may be a better predictor of stroke than stenosis, but analysis time limits clinical utility. This study tested the accuracy, reproducibility, and time saved of using an artificial intelligence (AI) derived semiautomatic software to measure CPV ("auto-CPV"). METHODS: Three-dimensional (3D) ultrasound images for 121 individuals were analyzed by 2 blinded operators to measure auto-CPV. Corresponding endarterectomy specimen volumes were calculated by the validated saline suspension technique. Inter-rater and intrarater agreement plus accuracy compared with the volume of the endarterectomized plaque were calculated. Measurement times were compared with previous manual CPV measurement. RESULTS: The mean difference between auto-CPV and surgical volume was small at (±s.d.) [95% confidence interval [CI]] 0.06 (0.24) [-0.41 to 0.54] cm3. The intraclass correlation (ICC) was strong at 0.91; 95% CI 0.86-0.94. Interobserver and intraobserver error was low with mean difference (±s.d.) [95%CI] 0.01 (0.26) [-0.5 to 0.5] cm3 and 0.03 (0.19) [-0.35 to 0.40] cm3 respectively. Both showed excellent ICC with narrow confidence intervals, ICC = 0.90; 95% CI (0.85-0.94) and ICC = 0.95; 95% CI (0.92-0.96). Auto-CPV measurement took 43% the time of manual planimetry; median (IQR) 05:39 (01:58) minutes compared to 13:05 (04:15) minutes, Wilcoxon rank-sum test, P < 0.01. CONCLUSIONS: Auto-CPV assessment is accurate, reproducible, and significantly faster than manual planimetry. Improved feasibility means that the utility of CPV can be assessed in large population studies to stratify risk in asymptomatic carotid disease or assess response to medical treatment.

Prospective evaluation of acute cerebral injury by DW-MRI following transcarotid artery revascularization using a double-layer micromesh stent.

BACKGROUND: Transcervical carotid artery revascularization (TCAR) has demonstrated a low overall stroke rate in carotid artery stenting (CAS). Furthermore, the use of a double-layer micromesh stent is expected to reduce embolization and plaque prolapse. The combination of TCAR and the double layer stent may lead to improved results compared to previously reported outcomes. The objective of this study is to present the findings of a prospective study including patients treated with the Roadsaver stent and TCAR. METHODS: Between January 2017 and May 2022, 85 patients were enrolled. Every patient underwent TCAR with the Roadsaver stent. As per our protocol, a neurological examination and an ultrasound were performed within 24 hours before and after the procedure, and again 30 days after. A diffusion-weighted magnetic resonance imaging (DW-MRI) was conducted 24 hours before the procedure and 48-72 hours after the procedure. The primary endpoint was the detection of new ischemic lesions on postoperative DW-MRI. The secondary endpoint was a composite of all strokes, death, and myocardial infarction within 30 days. RESULTS: Sixty-four patients (75.29%) were symptomatic, out of which 25 were treated within 14 days of the onset of the symptoms. Pre and postprocedural DW-MRI were performed in 83 patients. Postprocedural lesions were found in nine patients (10.84%). There were no strokes or death within 30 days, but two patients experienced a myocardial infarction. CONCLUSIONS: Our study suggests that the use of TCAR and the Roadsaver stent could be a safe alternative to carotid endarterectomy because it entails a low incidence of cerebral embolization, even in recently symptomatic and elderly patients.

Influencia del estrés oxidativo en la evolución de la aterosclerosis carotídea / Influence of oxidative stress on the progression of carotid atherosclerosis

Introducción y objetivo: el estrés oxidativo (EO) ha demostrado clara influencia en el desarrollo de las placas de ateroma por daños provocados en endotelio vascular. El objetivo de este trabajo es realizar un estudio de los principales marcadores de estrés oxidativo en pacientes con enfermedad aterosclerótica de la arteria carótida como signo de vulnerabilidad, analizar la implicación de la situación redox y el estado metabólico mitocondrial en patología aterosclerótica de la arteria carótida y su relación con clínica neurológica. Pacientes y métodos: se estudiaron las placas de ateroma obtenidas de pacientes intervenidos de endarectomía carotídea (asintomáticos y sintomáticos) en el Servicio de Angiología del Hospital Clínico Universitario de Valladolid en el año 2020. Se recogieron variables clínicas y demográficas y la existencia de sintomatología neurológica. Las características anatómicas y hemodinámicas se estudiaron mediante estudio eco Doppler y angiografía mediante tomografía computarizada en el preoperatorio. Se analizaron placas de ateroma como estimadores del grado de peroxidación lipídica que reflejaron el estado redox. Se ha estimado un tamaño muestral de 45 muestras en cada grupo, con una tasa de pérdidas de seguimiento del 5 %. Se estudiaron las diferencias entre los grupos mediante χ2 y la t de Student para determinar relación entre el potencial redox con las características morfológicas de placa de ateroma. Se utilizó el programa estadístico SPSS 27.0, aceptando como significativo un valor p < 0,05. Resultados: las placas de ateroma calcificadas mostraron mayor capacidad antioxidante con respecto a las placas de ateroma no calcificadas en el parámetro ABTS: 2,2-ácino-bis(ácido 3-etilbenzotiazolina-6-sulfónico) (2635,08 frente a 2803,28). La relación es estadísticamente significativa (p = 0,007)...(AU)

Introduction and objective: oxidative Stress (OS) has proven to have a clear impact on the development of atherosclerotic plaques due to the damage it causes to vascular endothelium. The aim of this study is to conduct a research on key oxidative stress markers in patients with carotid artery atherosclerotic disease as a sign of vulnerability, analyze the implications of the redox status and mitochondrial metabolic state in carotid artery atherosclerotic disease, and its relationship with neurological clinical presentation. Patients and methods: atherosclerotic plaques obtained from carotid endarterectomy patients (both asymptomatic and symptomatic) performed the Department of Angiology, Vascular and Endovascular Surgery of Hospital Clinico Universitario de Valladolid, Spain in 2020 will be examined. The clinical-demographic variables and the presence of neurological symptoms will be recorded. Anatomical and hemodynamic characteristics will be studied using Doppler ultrasound and coronary computed tomography angiography (CCTA) preoperatively. Atherosclerotic plaques will be analyzed as estimators of the degree of lipid peroxidation showing the redox state. A sample size of 45 speciments from each group has been estimated with a loss to follow-up rate of 5 %. Inter-group differences will be studied using the chi-square and Student’s t tests to establish the relationship between redox potential and morphological characteristics of the atheromatous plaque. SPSS 27.0 statistical software will be used, with a significance level set at p < 0.05. Results: calcified atherosclerotic plaques showed higher antioxidant capacity compared to non-calcified plaques in the ABTS parameter (2,2-azino-bis(3-ethylbenzthioziozline-6-sulfonic)) (2635.08 vs 2803.28), with statistically significant relationship (p = 0.007). They also exhibited greater antioxidant defense when analyzing catalase activity (160.73 vs 175.13) and SOD activity (1.11 vs 1.49) (p = 0.049)...(AU)

The dosage of thiopental as pharmacological cerebral protection during non-shunt carotid endarterectomy: A retrospective study.

Background: Thiopental has been used as a pharmacological cerebral protection strategy during carotid endarterectomy surgeries. However, the optimal dosage required to induce burst suppression on the electroencephalogram (EEG) remains unknown. This retrospective study aimed to determine the optimal dosage of thiopental required to induce burst suppression during non-shunt carotid endarterectomy. Methods: The Neurological Institute of Thailand Review Board approved the study. Data were collected from 2009 to 2019 for all non-shunt carotid endarterectomy patients who received thiopental for pharmacological cerebral protection and had intraoperative EEG monitoring. Demographic information, carotid stenosis severity, intraoperative EEG parameters, thiopental dosage, carotid clamp time, intraoperative events, and patient outcomes were abstracted. Results: The study included 57 patients. Among them, 24 patients (42%) achieved EEG burst suppression pattern with a thiopental dosage of 26.3±10.1 mg/kg/hr. There were no significant differences in perioperative events between patients who achieved burst suppression and those who did not. After surgery, 33.3% of patients who achieved burst suppression were extubated and awakened. One patient in the non-burst suppression group experienced mild neurological deficits. No deaths occurred within one month postoperative. Conclusions: The optimal dosage of thiopental required to achieve burst suppression on intraoperative EEG during non-shunt carotid endarterectomy was 26.3±10.1 mg/kg/hr.

Evidence and Mechanisms for Embolic Stroke in Contralateral Hemispheres From Carotid Artery Sources.

BACKGROUND: Disambiguation of embolus pathogenesis in embolic strokes is often a clinical challenge. One common source of embolic stroke is the carotid arteries, with emboli originating due to plaque buildup or perioperatively during revascularization procedures. Although it is commonly thought that thromboemboli from carotid sources travel to cerebral arteries ipsilaterally, there are existing reports of contralateral embolic events that complicate embolus source destination relationship for carotid sources. Here, we hypothesize that emboli from carotid sources can travel to contralateral hemispheres and that embolus interactions with collateral hemodynamics in the circle of Willis influence this process. METHODS AND RESULTS: We use a patient-specific computational embolus-hemodynamics interaction model developed in prior works to conduct an in silico experiment spanning 4 patient vascular models, 6 circle of Willis anastomosis variants, and 3 different thromboembolus sizes released from left and right carotid artery sites. This led to a total of 144 different experiments, estimating trajectories and distribution of approximately 1.728 million embolus samples. Across all cases considered, emboli from left and right carotid sources showed nonzero contralateral transport (P value <-0.05). Contralateral movement revealed a size dependence, with smaller emboli traveling more contralaterally. Detailed analysis of embolus dynamics revealed that collateral flow routes in the circle of Willis played a role in routing emboli, and transhemispheric movement occurred through the anterior and posterior communicating arteries in the circle of Willis. CONCLUSIONS: We generated quantitative data demonstrating the complex dynamics of finite size thromboembolus particles as they interact with pulsatile arterial hemodynamics and traverse the vascular network of the circle of Willis. This leads to a nonintuitive source-destination relationship for emboli originating from carotid artery sites, and emboli from carotid sources can potentially travel to cerebral arteries on contralateral hemispheres.

Silent Micro-Infarct in Carotid Artery Stenting: Who Has it and Why?

AIM: To compare the postprocedural cerebral diffusion-weighted imaging (DWI) findings in cases of carotid stenosis (CS)-related carotid plaques in terms of plaque morphology, degree of stenosis, and the use of a distal protection filter. Moreover, we used DWI to assess the asymptomatic cerebral embolism rates during carotid artery stending (CAS) operations performed for noncalcified versus calcified carotid plaques. MATERIAL AND METHODS: Our study included 99 patients admitted to the Ankara City Hospital Stroke Center in 2022. All of our patients have been evaluated and scheduled for CAS as a result of a decision made by the council. Cases of stenosis of > 50% in symptomatic patients and > 70% in asymptomatic patients were included. The patients were grouped according to their Doppler ultrasonography results. All of the patients underwent DWI within the first 24 hours after the procedure, and then two groups of patients were compared. RESULTS: A statistically significant difference was found between the distributions of the presence of silent micro-infarcts on DWI in terms of plaque characteristics (p < 0.001). In the patients with normal DWI findings, the percentage of calcified plaques was 38.7%, while the percentages of hypoechoic plaques, plaques with low echogenicity, and ulcerated plaques were 91.3%, 85.7%, and 78.8%, respectively. The rates of calcified plaques and ulcerated plaques differed in the group of patients with silent microinfarcts. The rate of silent micro-infarcts was 61.3% in the patients with calcified plaques, 8.7% in those with hypoechoic plaques, 14.3% in those with low-echogenicity plaques, and 21.2% in those with ulcerated plaques. CONCLUSION: The study found that carotid stents implanted in calcified and ulcerated plaques had a higher correlation with the presence of periprocedural asymptomatic ipsilateral DWI findings than those implanted in hypoechoic plaques and low-echogenicity plaques.

T1-T2 Mismatch Sign as a Predictor of Ipsilateral Ischemic Change After Carotid Artery Stenting.

BACKGROUND: Magnetic resonance (MR)-plaque imaging reflects the characteristics of carotid plaque. We evaluated the relationship between MR-plaque images and ischemic change after carotid artery stenting (CAS). METHODS: MR-plaque images were acquired from patients with carotid artery stenosis before CAS treatment. We calculated the relative signal intensity of plaque components compared with that of the sternocleidomastoid muscle and evaluated the presence/absence of T1-T2 mismatch and match sign. We then assessed the appearance of new ischemic lesions after CAS on diffusion-weighted imaging (DWI). Factors associated with the appearance of a high-intensity lesion on DWI were retrospectively analyzed. RESULTS: A total of 64 patients with carotid artery stenoses treated with CAS were included in this study. In univariate analysis, T1-T2 mismatch sign was associated with the appearance of high-intensity lesions on DWI after CAS (odds ratio [OR], 12.00; 95% confidence interval [CI], 3.593-40.072; P < 0.0001), whereas T1-T2 match sign and high intensity on T2-weighted imaging were negatively associated (OR, 0.061, 95% CI, 0.007-0.502, P = 0.009 and OR, 0.085; 95% CI, 0.022-0.334, P = 0.0004, respectively). In multivariate logistic regression analysis, T1-T2 mismatch sign was independently associated with the appearance of a high-intensity lesion on DWI after CAS (OR, 16.695; 95% CI, 1.324-210.52; P = 0.0295). CONCLUSIONS: T1-T2 mismatch sign on MR-plaque imaging is significantly associated with the appearance of new ischemic lesions after CAS. T1-T2 mismatch sign may be useful in considering treatment strategies for carotid artery stenosis.

Computational modeling of low-density lipoprotein accumulation at the carotid artery bifurcation after stenting.

Restenosis typically occurs in regions of low and oscillating wall shear stress, which also favor the accumulation of atherogenic macromolecules such as low-density lipoprotein (LDL). This study aims to evaluate LDL transport and accumulation at the carotid artery bifurcation following carotid artery stenting (CAS) by means of computational simulation. The computational model consists of coupled blood flow and LDL transport, with the latter being modeled as a dilute substance dissolved in the blood and transported by the flow through a convection-diffusion transport equation. The endothelial layer was assumed to be permeable to LDL, and the hydraulic conductivity of LDL was shear-dependent. Anatomically realistic geometric models of the carotid bifurcation were built based on pre- and post-stent computed tomography (CT) scans. The influence of stent design was investigated by virtually deploying two different types of stents (open- and closed-cell stents) into the same carotid bifurcation model. Predicted LDL concentrations were compared between the post-stent carotid models and the relatively normal contralateral model reconstructed from patient-specific CT images. Our results show elevated LDL concentration in the distal section of the stent in all post-stent models, where LDL concentration is 20 times higher than that in the contralateral carotid. Compared with the open-cell stents, the closed-cell stents have larger areas exposed to high LDL concentration, suggesting an increased risk of stent restenosis. This computational approach is readily applicable to multiple patient studies and, once fully validated against follow-up data, it can help elucidate the role of stent strut design in the development of in-stent restenosis after CAS.

Impact of Carotid Stent Design on Embolic Filter Debris Load During Carotid Artery Stenting.

BACKGROUND: The carotid stent design may influence the risk of embolization during carotid artery stenting. The aim of the study was to assess this risk by comparing the quantity of embolized material captured by filters during carotid artery stenting, using different stent designs. METHODS: We conducted a single-center retrospective study of patients undergoing carotid artery stenting for asymptomatic carotid stenosis >70% (2010-2022) in a tertiary academic hospital (Padua University Hospital, Italy). Carotid stents were classified according to their design as open-cell (OCS), closed-cell (CCS), or micromesh stents (MMS). A distal filter protection was used in all patients, and the amount of captured embolized particles was semiautomatically analyzed using a dedicated software (Image-Pro Plus, Media Cybernetics). Primary end point was embolic filter debris (EFD) load, defined as the ratio of the filter area covered by particulate material to the total filter area. Secondary end points were 30 days major stroke and death. RESULTS: Four-hundred-eighty-one carotid artery stentings were included; 171 (35%) using an OCS, 68 (14%) a CCS, and 242 (50%) a MMS. Thirty-days mortality was 0.2% (n=1) and major stroke rate was 0.2% (P=0.987). Filters of patients receiving MMS were more likely to be free from embolized material (OCS, 30%; CCS, 13%; MMS, 41%; P<0.001) and had a lower EFD load (OCS, 9.1±14.5%; CCS, 7.9±14.0%; MMS, 5.0±9.1%; P<0.001) compared with other stent designs. After stratification by plaque characteristics, MMS had a lower EFD load in cases of hypoechogenic plaque (OCS, 13.4±9.9%; CCS, 10.9±8.7%; MMS, 6.5±13.1%; P<0.001), plaque length>15 mm (OC, 10.2±15.3; CC, 8.6±12.4; MM, 8.2±13.6; P<0.001), and preoperative ipsilateral asymptomatic ischemic cerebral lesion (OCS, 12.9±16.8%; CCS, 8.7±19.5%; MMS, 5.4±9.7%; P<0.001). After multivariate linear regression, use of MMS was associated with lower EFD load (P=0.038). CONCLUSIONS: The use of MMS seems to be associated with a lower embolization rate and EFD load, especially in hypoechogenic and long plaques and in patients with a preoperative evidence of asymptomatic ischemic cerebral lesion.

"Dual Internal Shunts Technique" for Carotid Endarterectomy with Carotid Vertebral Anastomosis: Technical Note.

In revascularization of internal carotid stenosis with carotid vertebrobasilar anastomoses, attention should be paid not only to the anterior circulation but also to the posterior circulation cerebral infarction. A 74-year-old man was referred for treatment of carotid artery stenosis; NASCET 75% stenosis in the right internal carotid artery and acute cerebral infarction were confirmed. Occlusion of the left subclavian artery and vascular anastomosis between the right external carotid artery and the vertebral artery were indicated, such that the right external carotid artery may maintain blood flow to the vertebrobasilar artery. Therefore, dual shunts were used for the common and internal carotid arteries and the common and external carotid arteries to maintain blood flow during carotid endarterectomy. Management of the dual shunts is difficult due to the instable parallel placement of the common carotid artery shunt balloons. To solve this problem, the "dual internal shunts technique" was performed. The first shunt was inserted into the external and common carotid arteries, and the second into the internal and common carotid arteries. The shunt balloon on the common carotid artery side was placed distal to the first shunt balloon so that the dual balloons were placed in a tandem position. The proximal balloon was subsequently deflated gradually to improve flow in both shunts. The procedure is technically easy and safe.

[Treatment experience of neck tumor surgeries involving carotid artery].

Objective:To investigate surgical treatment of carotid artery diseases in neck tumor surgery. Methods:A retrospective analysis of the clinical data on carotid artery treatment was conducted in the five cases of neck tumor surgeries treated at Department of Surgical Oncology, the First Peoples Hospital of Lanzhou from March 2010 to May 2020. Surgical methods, including carotid artery resection and ligation, tumor-involved artery resection and vascular reconstruction, and tumor peeling and carotid rupture repairing were used, respectively. Results:Five cases were successfully operated on. One case of carotid artery ligation was followed by intermittent dizziness and decreased contra-lateral limb strength after the surgery. The remaining patients exhibited no neurological complications. A patient with cervical low-grade myofibroblastoma developed into lung metastases 8 months after the surgery. Another patient with cervical lymph node metastases in papillary thyroid cancer developed into lung metastases 24 months after the surgery. Conclusion:Currently, surgical methods for clinical treatment of diseased carotid arteries include carotid artery resection and ligation, simple tumor peeling, tumor invasion artery resection and vascular reconstruction, and interventional therapy. Each surgical method has its own advantages and disadvantages. Therefore, the choice of treatment depends on the patient's specific conditions, physician's clinical experience, and the equipment available.