Balloon neck-plasty to create a wide-necked aneurysm in the elastase-induced rabbit model

PURPOSE

The elastase-induced aneurysm (EIA) model in rabbits has been proposed for translational research; however, the adjustment of aneurysm neck size remains challenging. In this study, the technical feasibility and safety of balloon neck-plasty to create a wide-necked aneurysm in rabbit EIA model were investigated.

METHODS

Male New Zealand White rabbits (N = 15) were randomly assigned to three groups: group A, EIA creation without neck-plasty; group B, neck-plasty immediately after EIA creation; group C, neck-plasty 4 weeks after EIA creation. The diameter of balloon used for neck-plasty was determined 1 mm larger than origin carotid artery diameter. All rabbits were euthanized 4 weeks after their final surgery. Aneurysm neck, height, dome-to-neck (D/N) ratio, and histologic parameters were compared among the groups.

RESULTS

Aneurysm creation was technically successful in 14 out of 15 rabbits (93.3%), with one rabbit experiencing mortality due to an adverse anesthetic event during the surgery. Saccular and wide-necked aneurysms were successfully created in all rabbits. Aneurysm neck was significantly greater in groups B and C compared to group A (all P < .05). D/N ratio was significantly lower in groups B and C compared to group A (all P < .05). Additionally, tunica media thickness, vessel area, and luminal area were significantly greater in groups B and C compared to group A (all P < .05). These variables were found to be significantly greater in group B compared to group C (all P < .05).

CONCLUSION

The creation of a wide-necked aneurysm using balloon neck-plasty after elastase induction in rabbits has been determined to be technically feasible and safe.

CD38 deficient mice are not protected from atherosclerosis

CD38 is a multifunctional enzyme implicated in chemotaxis of myeloid cells and lymphocyte activation, but also expressed by resident cells such as endothelial and smooth muscle cells. CD38 is important for host defense against microbes. However, CD38's role in the pathogenesis of atherosclerosis is controversial with seemingly conflicting results reported so far. To clarify the discrepancy of current literature on the effect of CD38 ablation on atherosclerosis development, we implanted a shear stress modifier around the right carotid artery in CD38-/- and WT mice. Hypercholesterolemia was induced by human gain-of-function PCSK9 (D374Y), introduced using AAV vector (serotype 9), combined with an atherogenic diet for a total of 9 weeks. Atherosclerosis was assessed at the aortic root, aortic arch and the right carotid artery. The findings can be summarized as follows: i) CD38-/- and WT mice had a similar atherosclerotic burden in all three locations, ii) No significant differences in monocyte infiltration or macrophage content could be seen in the plaques, and iii) The amount of collagen deposition in the plaques were also similar between CD38-/- and WT mice. In conclusion, our data suggest that CD38-/- mice are neither protected against nor prone to atherosclerosis compared to WT mice.

Facilitating Repeat Intracarotid Injections in Mouse Models by a Novel Injection Site Repair Technique

Given recent advances in the delivery of novel antitumor therapeutics using endovascular selective intraarterial delivery methods in neuro-oncology, there is an urgent need to develop methods for intracarotid injections in mouse models, including methods to repair the carotid artery in mice after injection to allow for subsequent injections. We developed a method of intracarotid injection in a mouse model to deliver therapeutics into the internal carotid artery (ICA) with two alternative procedures. During injection, the needle is inserted into the common carotid artery (CCA) after tying a suture around the external carotid artery (ECA) and injected therapeutics are delivered into the ICA. Following injection, the common carotid artery (CCA) can be ligated, which limits the number of intracarotid injections to one. The alternative procedure described in this article includes a modification where intracarotid artery injection is followed by injection site repair of the CCA, which restores blood flow within the CCA and avoids the complication of cerebral ischemia seen in some mouse models. We also compared the delivery of bone marrow-derived human mesenchymal stem cells (BM-hMSCs) to intracranial tumors when delivered through intracarotid injection with and without injection site repair following the injection. Delivery of BM-hMSCs does not differ significantly between the methods. Our results demonstrate that injection site repair of the CCA allows for repeat injections through the same artery and does not impair the delivery and distribution of injected material, thus providing a model with greater flexibility that more closely emulates intracarotid injection in humans.

A new very-small-bore Simmons guiding sheath for transradial neurointervention: Technical note and initial experience

Transradial access during neurointerventions has increased in popularity because of reduced complications and patient preference. Nevertheless, transradial cannulation into the left common carotid artery can be difficult technically because of the lack of catheter support in the aortic arch. Furthermore, the use of large sheaths can increase the risk of complications at the access site. Here, we developed a new very-small-bore transradial system using a 3F Simmons guiding sheath, to increase the procedural success rate and minimize access-site complications. This system can represent a valuable treatment option for neurointerventions and has the potential to expand the indications for transradial access.

Trans-Distal Radial Artery Carotid Revascularization with Forearm Flow Reversal: An Alternative Option of CAS in the TCAR Era

BACKGROUND

Transcarotid artery revascularization (TCAR) has emerged as an alternative to carotid artery stenting (CAS). TCAR demonstrated its superiority by avoiding femoral artery puncture and establishing proximal protection without crossing the stenotic lesion. In the TCAR era, we focused on the possibility of a trans-distal radial approach (DRA). A balloon-guide catheter was navigated via DRA to establish proximal protection before lesion crossing. The forearm subcutaneous vein was used as the flow-reversal circuit.

METHODS

Six internal carotid artery stenosis patients underwent CAS using "the forearm flow reversal technique." Every procedure was performed under continuous flow reversal from the common carotid artery to the forearm cephalic vein.

RESULTS

Successful revascularization was achieved without ischemic or access-site complications. The distal radial artery was patent at discharge in all cases.

CONCLUSIONS

Trans-distal radial CAS with forearm flow reversal is a feasible and less invasive technical option.

The influence of physical activity and sex on carotid artery longitudinal wall motion in younger healthy adults

Carotid artery longitudinal wall motion (CALM) is a novel preclinical marker for atherosclerosis that describes the axial anterograde and retrograde motion of the intima-media complex. While regular physical activity and sex are known to independently influence arterial stiffness, their roles on axial arterial wall behaviour are unknown. The purpose of this study is to examine whether physical activity and sex impact CALM. We hypothesized that CALM retrograde displacement and total amplitude would be greater in females and active individuals, as a function of arterial stiffness. Fifty-seven young healthy adults (30 females; aged 22 ± 3 years) were evaluated for CALM outcomes and arterial stiffness and grouped by physical activity based on active (V̇O2 = 44.2 ± 8.9 mL/kg/min) or sedentary (V̇O2 = 33.7 ± 6.7 mL/kg/min) lifestyles defined by the Canadian 24-Hour Movement Guidelines. Arterial stiffness and CALM were measured by carotid-femoral pulse wave velocity (cfPWV) and vascular ultrasound at the right common carotid artery with speckle tracking analysis, respectively. cfPWV was greater in males (p < 0.01) with no interaction between sex and physical activity (p = 0.90). CALM anterograde displacement was greater in males (p = 0.03) resulting in a forward shift in total CALM pattern, which became less prominent when controlling for mean arterial pressure (p = 0.06). All other CALM outcomes were not different between activity and sex. V̇O2max was not correlated to any CALM outcome (all p > 0.05). Apparent sex differences in vascular function extend to novel CALM outcomes but may be confounded by blood pressure. We recommend sex-balanced design and reporting in future studies due to possible anterograde-shifted CALM patterns in healthy males.

Sentinel ear bleed as a presenting sign for carotid artery blowout due to aspergillus abscess in parapharyngeal space in an immunocompetent infant

Parapharyngeal abscesses leading to complications, although rare after the advent of antibiotics, can lead to serious complications. One such complication is carotid erosion that can lead to a potentially fatal carotid artery blowout. We report a case of a previously healthy infant who presented with fever, ear bleed and progressively increasing swelling in the right side of his neck that led to airway compromise. The child required immediate securing of the airway at presentation. Imaging revealed lobulated abscess with multiple bleeding points eroding the carotid vessels, along with internal jugular venous thrombus. Surgical exploration was done and abscess debulked. Histopathology revealed aspergillus, which was treated with antifungals. He was discharged on oral warfarin after 40 days of hospital stay and remains well on follow-up. Sentinel ear bleed warrants close observation for possibility of carotid artery blowout in children with parapharyngeal abscesses.

Is low carotid bifurcation determined by vertebral level always convenient for surgical approach?

Although high-level carotid bifurcation (HCB) could lead to notable surgical difficulty, the definitive reference point for HCB is unclear. HCB is typically characterized as carotid bifurcation (CB) located higher than the level of the third cervical vertebra (C), however, a major obstacle regarding carotid artery surgical exposure is angle of the mandible (AM). The objective of this study was to investigate CB level, define HCB in relation to AM and vertebral levels, and measure the vertical distance from HCB to ipsilateral AM. Moreover, the percentage of surgically challenged CBs, misclassified as low CBs (LCB) based on vertebral level, was investigated. Patients who underwent neck computed tomography angiography were retrospectively studied. HCBs were classified into two categories: CBs above the C3 and either at or above the ipsilateral AM. Of 172 CBs (86 patients; 57 men, 29 women), CB was mostly found at C3 (44.19%), whereas AM was commonly located at C2 (51.16%). Based on vertebral level and AM, HCBs were detected in 10.47% and 20.35% of CBs, respectively. The association of HCBs determined by either C3 or AM between both sides in each individual was nonsignificant (p>0.05), but HCBs determined by C3 level were predominant in women (OR = 3.58, 95%CI = 1.31-9.80). Considering both C3 and AM, there was 8.72% of HCBs. The remaining 91.28% was classified as LCBs, including 11.63% of CBs located at both C3 and AM which were actually classified as HCBs if determined by AM. In cases of CBs above AM level, the mean vertical distance was as high as 6.56 ±2.41mm.

TRIGLYCERIDE - GLUCOSE INDEX, REMNANT CHOLESTEROL AND COMMON CAROTID ARTERY INTIMA-MEDIA THICKNESS AS AN ATHEROSCLEROTIC MARKER IN ISCHEMIC STROKE PATIENTS

Ischemic stroke (IS) is a major global health concern, often resulting from atherosclerosis and insulin resistance (IR). The triglyceride-glucose index (TyG index), remnant cholesterol (RC), and common artery intima-media thickness (CIMT) are potential markers for assessing atherosclerosis and cardiovascular risk in IS patients. A cross-sectional study was conducted to investigate the association between TyG index, RC, CIMT, and IS in adult patients recruited from a hospital. Demographic, clinical, and laboratory data were collected, and statistical analysis was performed. The study included 50 participants with a balanced gender distribution and a mean age of 57.64 years. Laboratory characteristics showed notable values, and CIMT > 0.6 mm was associated with higher NIH Stroke Scale scores. RC exhibited significant correlations with age, CIMT, lipid profile, and TyG index. The study highlights the potential of TyG index, RC, and CIMT as atherosclerotic markers in IS patients. Favorable prognostic outcomes were observed, emphasizing the importance of early diagnosis and management to improve patient outcomes.

Use of Carotid Web Angioarchitecture for Stroke Risk Assessment

OBJECTIVE

To examine the usefulness of carotid web (CW), carotid bifurcation and their combined angioarchitectural measurements in assessing stroke risk.

METHODS

Anatomic data on the internal carotid artery (ICA), common carotid artery (CCA), and the CW were gathered as part of a retrospective study from symptomatic (stroke) and asymptomatic (nonstroke) patients with CW. We built a model of stroke risk using principal-component analysis, Firth regression trained with 5-fold cross-validation, and heuristic binary cutoffs based on the Minimal Description Length principle.

RESULTS

The study included 22 patients, with a mean age of 55.9 ± 12.8 years; 72.9% were female. Eleven patients experienced an ischemic stroke. The first 2 principal components distinguished between patients with stroke and patients without stroke. The model showed that ICA-pouch tip angle (P = 0.036), CCA-pouch tip angle (P = 0.036), ICA web-pouch angle (P = 0.036), and CCA web-pouch angle (P = 0.036) are the most important features associated with stroke risk. Conversely, CCA and ICA anatomy (diameter and angle) were not found to be risk factors.

CONCLUSIONS

This pilot study shows that using data from computed tomography angiography, carotid bifurcation, and CW angioarchitecture may be used to assess stroke risk, allowing physicians to tailor care for each patient according to risk stratification.

Patients with a large ossification of the posterior longitudinal ligament have a higher incidence of arteriosclerosis in the carotid artery

PURPOSE

This study aimed to investigate the impact of the severity of cervical ossification of the posterior longitudinal ligament (OPLL) on the incidence of arteriosclerosis in the carotid artery.

METHODS

Patients with OPLL-induced cervical myelopathy were prospectively enrolled. The study involved analyzing patient characteristics, blood samples, computed tomography scans of the spine, and intima-media thickness (IMT) measurements of the common carotid artery. Patients were divided into two groups based on the size of the cervical OPLL to compare demographic data, comorbidities, and the presence of thickening of the carotid intima-media (max IMT ≥ 1.1 mm).

RESULTS

The study included 96 patients (mean age: 63.5 years; mean body mass index: 26.9 kg/m2; 71.8% male; 35.4% with diabetes mellitus). The mean maximum anteroposterior (AP) diameter of the OPLL was 4.9 mm, with a mean occupancy ratio of 43%. The mean maximum IMT was 1.23 mm. Arteriosclerosis of the carotid artery was diagnosed in 62.5% of the patients. On comparing the two groups based on OPLL size, the group with larger OPLL (≥ 5 mm) had a higher BMI and a greater prevalence of carotid intima-media thickening. This significant difference in the prevalence of carotid intima-media thickening persisted even after adjusting for patient backgrounds using propensity score matching.

CONCLUSIONS

Patients with a larger cervical OPLL showed a higher frequency of intima-media thickening in the carotid artery.

NO Deficiency Compromises Inter- and Intrahemispheric Blood Flow Adaptation to Unilateral Carotid Artery Occlusion

Carotid artery stenosis (CAS) affects approximately 5-7.5% of older adults and is recognized as a significant risk factor for vascular cognitive impairment (VCI). The impact of CAS on cerebral blood flow (CBF) within the ipsilateral hemisphere relies on the adaptive capabilities of the cerebral microcirculation. In this study, we aimed to test the hypothesis that the impaired availability of nitric oxide (NO) compromises CBF homeostasis after unilateral carotid artery occlusion (CAO). To investigate this, three mouse models exhibiting compromised production of NO were tested: NOS1 knockout, NOS1/3 double knockout, and mice treated with the NO synthesis inhibitor L-NAME. Regional CBF changes following CAO were evaluated using laser-speckle contrast imaging (LSCI). Our findings demonstrated that NOS1 knockout, NOS1/3 double knockout, and L-NAME-treated mice exhibited impaired CBF adaptation to CAO. Furthermore, genetic deficiency of one or two NO synthase isoforms increased the tortuosity of pial collaterals connecting the frontoparietal and temporal regions. In conclusion, our study highlights the significant contribution of NO production to the functional adaptation of cerebrocortical microcirculation to unilateral CAO. We propose that impaired bioavailability of NO contributes to the impaired CBF homeostasis by altering inter- and intrahemispheric blood flow redistribution after unilateral disruption of carotid artery flow.

M6A plays a potential role in carotid atherosclerosis by modulating immune cell modification and regulating aging-related genes

RNA N6-methyladenosine (m6A) regulators play essential roles in diverse biological processes, including immune responses. Mounting evidence suggests that their dysregulation is intricately linked to numerous diseases. However, the role of m6A-associated genes in carotid atherosclerosis and their relationship with aging and immune cells remain unclear. Analyze the expression profiles of m6A-related genes in carotid atherosclerosis-related datasets. Based on the expression patterns of m6A-related genes, perform consistent clustering analysis of carotid atherosclerosis samples and investigate associated immune cell infiltration patterns and aging characteristics. Develop an m6A prediction model specific to carotid atherosclerosis and analyze the relationships between immune cells infiltration and aging features. The m6A methylation modification level exhibited a substantial decrease in early-stage carotid atherosclerosis samples compared to late-stage carotid atherosclerosis samples. Subsequently, two distinct m6A subtypes were defined through consensus clustering analysis, with the lower m6A modification level group showing associations with heightened immune cell infiltration and increased expression of aging-related genes. A model composed of five m6A-related genes was formulated, and the results indicated that this model possesses effective predictive and therapeutic capabilities for carotid atherosclerosis. Furthermore, the downregulation of YTHDC1 expression resulted in elevated expression of inflammatory factors and a decrease in the expression of the aging-related gene RGN. Single-cell data analysis suggests that the reduced expression of YTHDC1 may decrease the degradation of inflammation-related factors in macrophages, leading to a highly inflammatory state in the carotid artery wall. Furthermore, the sustained release of inflammatory factors may increase the expression of the aging-related gene RGN in vascular smooth muscle cells, further exacerbating the progression of atherosclerosis. A reduced level of m6A methylation modification could enhance inflammation and expedite cellular aging, thereby contributing to the development of carotid atherosclerosis.

Effect of Asymptomatic Common Carotid Artery Dissection on the Prognosis of Patients With Acute Type A Aortic Dissection

BACKGROUND

Acute type A aortic dissection can extend upwards to involve the common carotid artery. However, whether asymptomatic common carotid artery dissection (CCAD) requires surgical repair remains controversial. This study aimed to explore the effect of asymptomatic CCAD without surgical intervention on the prognosis of patients who underwent surgery for acute type A aortic dissection.

METHODS AND RESULTS

Between January 2015 and December 2017, 485 patients with no neurological symptoms who underwent surgery for acute type A aortic dissection were enrolled in this retrospective cohort study. The patients were divided into 2 groups based on the exposure factor of CCAD. CCAD was detected in 111 patients (22.9%), and after adjusting baseline data (standardized mean difference <0.1), the 30-day mortality (17.1% versus 6.0%, P<0.001) and incidence of fatal stroke (7.7% versus 1.6%, P=0.001) were significantly higher in the group with CCAD. Univariable and multivariable Cox regression analyses found CCAD as an independent risk factor for 30-day mortality (hazard ratio [HR], 2.8 [95% CI, 1.5-5.2]; P=0.001). At a median follow-up of 6.2 years (interquartile range, 5.6-6.9 years), landmark analysis with a cutoff value of 1 month postoperatively showed a significant increase in mortality in the group with CCAD, especially in the first month (log-rank P=0.002) and no significant difference in survival after the first month postoperatively between the 2 groups (log-rank P=0.955).

CONCLUSIONS

Asymptomatic CCAD increased the risk of early fatal stroke and death in patients with acute type A aortic dissection after surgery but did not affect midterm survival in patients who survived the early postoperative period.

Branch retinal artery occlusion with congenital common carotid artery and internal carotid artery occlusion: A case report

PURPOSE

To report a case of branch retinal artery occlusion (BRAO) of the left eye combined with left congenital common carotid artery occlusion (CCAO) and internal carotid artery occlusion (ICAO).

METHODS

Case report.

RESULTS

A 36-year-old man presented with sudden vision loss of only the left eye without any signs or symptoms of brain diseases. Fluorescein fundus angiography (FFA) showed left BRAO, and computed tomography angiography (CTA) of the head and neck showed entire left CCAO and ICAO. The patient's left vertebral artery was anastomosed with the left occipital artery via the muscular branch, supplying blood retrogradely to the left external carotid artery. The right internal carotid artery compensated for blood supply to the left anterior cerebral artery and middle cerebral artery via anterior communication, and the left posterior communication artery compensated for blood supply to the left middle cerebral artery.

CONCLUSIONS

To our knowledge, this study was the first to report a case of BRAO combined with congenital CCAO and ICAO with vision loss as the first symptom and proposed the importance of head and neck examination in retinal artery occlusion at the first visit to a doctor.

Combination endovascular and microsurgical treatment of partially thrombosed ruptured ICA terminus aneurysm, with common carotid artery to MCA bypass via saphenous vein graft and parent vessel sacrifice after coil embolization

A 63-year-old woman presented with ruptured giant ICA terminus aneurysm, temporized with coil embolization and definitively treated with parent vessel sacrifice and high-flow bypass.

Neuroprotective association of preoperative renin-angiotensin system blocking agents use in patients undergoing carotid interventions

OBJECTIVE

The optimal medical management strategy in the periprocedural period for patients undergoing carotid artery interventions is not well described. Renin-angiotensin-system blocking (RASB) agents are considered to be among the first line anti-hypertensive agents; however, their role in the perioperative period is unclear. The objective of this study was to examine the relationship between the use of RASB agents on periprocedural outcomes in patients undergoing carotid interventions-carotid endarterectomy (CEA), transfemoral carotid artery stenting (CAS), and transcervical carotid artery revascularization (TCAR).

METHOD

The Society for Vascular Surgery Quality Initiative database was queried for all patients undergoing CAS, CEA, and TCAR between 2003 and 2020. Patients were stratified into two groups based upon their use of RASB agents in the periprocedural period. The primary endpoint was periprocedural neurologic events (including both strokes and transient ischemic attacks (TIAs)). The secondary endpoints were peri-procedural mortality and significant cardiac events, including myocardial infarction, dysrhythmia, and congestive heart failure.

RESULTS

Over 150,000 patients were included in the analysis: 13,666 patients underwent TCAR, 13,811 underwent CAS, and 125,429 underwent CEA for carotid artery stenosis. Overall, 52.2% of patients were maintained on RASB agents. Among patients undergoing CEA, patients on RASB agents had a significantly lower rate of periprocedural neurologic events (1.7% versus 2.0%, p =0.001). The peri-procedural neurological event rate in the TCAR cohort was similarly reduced in those treated with RASB agents, but did not reach statistical significance (2.0% vs 2.4%, p = 0.162). Among patients undergoing CAS, there was no difference in perioperative neurologic events between the RASB treated and untreated cohorts (3.4% vs 3.2%, p = 0.234); however, the use of RASB agents was significantly associated with lower mortality (1.2% vs 1.7%, p =0.001) with CAS. The use of preoperative RAS-blocking agents did not appear to affect the overall rates of adverse cardiac events with any of the three carotid intervention types, or periprocedural mortality following CEA or TCAR. On multivariable analysis, the use of RAS-blocking agents was independently associated with lower rates of post-procedural neurologic events in patients undergoing CEA (OR 0.819, CI 0.747-0.898; p = 0.01) and TCAR (OR 0.869, CI 0.768-0.984; p = 0.026), but not in those undergoing CAS (OR 0.967, CI 0.884-1.057; p = 0.461).

CONCLUSION

The use of peri-procedural RASB agents was associated with a significantly decreased rate of neurologic events in patients undergoing both CEA and TCAR. This effect was not observed in patients undergoing CAS. As carotid interventions warrant absolute minimization of perioperative complications in order to provide maximum efficacy with regard to stroke protection, the potential neuro-protective effect associated with RASB agents use following CEA and TCAR warrants further examination.

Investigation of the clinical effects of acipimox in patients with vulnerable carotid atherosclerosis

OBJECTIVE

To investigate the clinical effects of acipimox in patients with vulnerable carotid atherosclerosis.

METHODS

80 patients with vulnerable carotid atherosclerosis who were admitted to the Department of Cardiology in Wuxi Second People's Hospital between February 2020 and October 2021 were enrolled in this study. All of these patients were randomly divided into an observation group (n = 40), who were given acipimox and conventional treatment, and a control group (n = 40), who were given conventional treatment. The levels of blood lipids and adiponectin (APN), the carotid intima-media thickness (IMT), the area, thickness and number of CAS, peak systolic velocities (PSV) and end-diastolic blood velocity (EDV) of common carotid artery (CCA), and the level of inflammatory markers were measured and compared between the two groups pretherapy and posttreatment. Then, the adverse events were collected and compared between the two groups posttreatment.

RESULTS

The demographics and basic clinical characteristics were not significantly different between the two groups. At posttreatment, the levels of TC, LDL-C, ANP, IL-6, TNF-α and hs-CRP in the observation group were significantly lower than those in the control group at posttreatment. Moreover, the IMT and the area and thickness of CAS in the observation group were significantly lower than those in the control group. After treatment, PSV was lower and EDV was higher in two groups than before treatment; after treatment, compared with control group, PSV in observation group was lower, while EDV was higher. Most importantly, the rate of adverse events was similar in the two groups.

CONCLUSIONS

Acipimox reduced the blood lipid levels in patients with vulnerable carotid atherosclerosis. It also stabilized vulnerable plaques and reduced CAS.

Compromised homeostasis in aged carotid arteries revealed by microstructural studies of elastic lamellae

Healthy arteries are continuously subjected to diverse mechanical stimuli and adapt in order to maintain a mechanical homeostasis which is characterized by a uniform distribution of wall stresses. However, aging may compromise the homeostatic microenvironment within arteries. Structural heterogeneity has been suggested as a potential microstructural mechanism that could lead to homogeneous stress distribution across the arterial wall. Our previous study on the unfolding and stretching of the elastic lamellae revealed the underlying microstructural mechanism for equalizing the circumferential stresses through wall; inner elastic layers are wavier and unfold more than the outer layers which helps to evenly distribute lamellar stretching (Yu et al., 2018). In this study, we investigated the effect of aging on lamellar deformation and its implications for tissue homeostasis. Common carotid arteries from aged mice were imaged under a multi-photon microscope while subjected to biaxial extension and inflation at five different pressures ranging from 0 up to 120 mmHg. Lamellar unfolding during pressurization was then determined from the reconstructed cross-sectional images of elastic lamellae. Tissue-level circumferential stretch was combined with the lamellar unfolding to calculate lamellar stretching. Our results revealed that the straightness gradient of aged elastic lamellae is similar to the young ones. However, during pressurization, the inner elastic lamella of the aged mice unfolded significantly more than the inner layer in young arteries. An important finding of our study is the uneven increase in inter-lamellar space which contributed to a nonuniform stretching of the elastic lamellae of aged mice arteries, elevated stress gradient, and a shifting of the load-bearing component to adventitia. Our results shed light into the complex microstructural mechanisms that take place in aging and adversely affect arterial mechanical behavior and homeostasis.

Discrepancies in clavicle-to-carotid bifurcation length measurements for transcarotid artery revascularization using different imaging modalities

OBJECTIVE

Transcarotid artery revascularization (TCAR) has emerged as an effective method for carotid artery stenting. However, anatomic eligibility for TCAR is most often limited by an inadequate clavicle-to-carotid bifurcation length of <5 cm. Preoperative clavicle-to-carotid bifurcation distances may be underestimated when using conventional straight-line measurements on computed tomographic angiography (CTA) imaging. We therefore compared clavicle-to-carotid bifurcation lengths as measured by straight-line CTA, center-line CTA, and intraoperative duplex ultrasound (US), to assess potential differences.

METHODS

We conducted a single-center, retrospective review of consecutive TCAR procedures performed between 2016 and 2019 for atherosclerotic carotid disease. For each patient, we compared clavicle-to-carotid bifurcation lengths measured by straight-line CTA, center-line CTA using TeraRecon image reconstruction, and intraoperative duplex US with neck extension and rotation. We further assessed patient and imaging characteristics in individuals with a ≥0.5 cm difference among the measurement methods. In particular, common carotid artery (CCA) tortuosity, defined as the inability to visualize the entire CCA from clavicle to carotid bifurcation on both a single coronal and sagittal imaging cut, was examined as a contributing factor for these discrepancies.

RESULTS

Of the 70 TCAR procedures identified, 46 had all three imaging modalities available for review. The median clavicle-to-carotid bifurcation length was found to be 6.4 cm (interquartile range [IQR], 5.4-6.7 cm) on straight-line CTA, 7.0 cm (IQR, 6.0-7.5 cm) on intraoperative duplex US, and 7.2 cm (IQR, 6.5-7.5 cm) on center-line CTA (P < .001). Patients with a ≥0.5 cm difference between their straight-line CTA and either their intraoperative duplex US or center-line CTA measurements were more likely to have tortuous CCAs (60.0% vs 19.1%; P = .01; 51.4% vs 0.0%; P = .01). There were no notable differences in age, gender, prior neck/cervical spine surgery, or neck immobility among these individuals. In patients with tortuous CCAs, duplex US and center-line CTA measurements added 1.0 cm (IQR, 0.6-1.5 cm) and 1.1 cm (IQR, 0.9-1.6 cm) more in length than straight-line CTA measurements, respectively. There was a strong linear correlation between the additional lengths provided by duplex US measurements and those provided by center-line CTA measurements for each individual within the tortuous CCA group (r = 0.83).

CONCLUSIONS

The use of straight-line CTA during preoperative planning can underestimate the clavicle-to-carotid bifurcation lengths in patients undergoing carotid revascularization, particularly in those with tortuous CCAs. Both duplex US performed with extended-neck surgical positioning and center-line CTA provide similar and longer carotid length measurements, and should be utilized in patients with tortuous carotid vessels to better determine TCAR anatomic eligibility.

Potentiation of active force by cyclic strain in sheep carotid arterial smooth muscle

The ability to generate force in large arteries is known to be augmented by cyclic strain that mimics the mechanically dynamic in vivo environment associated with blood pressure fluctuation experienced by these arteries. Cyclic strain does not induce a contractile response, like that observed in the myogenic response seen in small arteries, but prompts a substantial increase in the response to electrical stimulation. We coined this phenomenon "force potentiation." Because protein kinase C (PKC) and rho-kinase (ROCK) are known to play a role in increasing contractility of arterial smooth muscle by inhibition of myosin light chain phosphatase, and integrin-link kinase (ILK) is crucial in mechanotransduction, we examined how inhibition of these kinases affected force potentiation in sheep carotid artery. We found that phosphorylation of the regulatory myosin light chain was enhanced by cyclic strain, but the enhancement was observed only in activated, not in relaxed muscle. Inhibition of ROCK diminished force potentiation and active isometric force, likely due to the disinhibition of myosin light chain phosphatase. Inhibition of PKC abolished force potentiation without an effect on active force, suggesting a more exclusive role of PKC (compared with ROCK) in mediating force potentiation. Inhibition of ILK had a similar effect as PKC inhibition, suggesting that ILK may be an upstream kinase for PKC activation by mechanical stimuli. Taken together, the findings suggest that ILK, PKC, and ROCK are important kinases in the signal transduction pathway that mediate the effect of mechanical strain on force potentiation.NEW & NOTEWORTHY When subjected to mechanical strain, smooth muscle from large arteries has the ability to increase its force generation (force potentiation), which could be important in autoregulation of blood pressure. This phenomenon, however, does not involve a myogenic response, such as the one seen in small arteries and arterioles. Our work shows the involvement of ILK, PKC, and ROCK in the signal transduction pathway that mediates the force-potentiating effect of mechanical strain in large arteries.

Assessment of cerebral autoregulatory function and inter-hemispheric blood flow in older adults with internal carotid artery stenosis using transcranial Doppler sonography-based measurement of transient hyperemic response after carotid artery compression

Unhealthy vascular aging promotes atherogenesis, which may lead to significant internal carotid artery stenosis (CAS) in 5 to 7.5% of older adults. The pathogenic factors that promote accelerated vascular aging and CAS also affect the downstream portion of the cerebral microcirculation in these patients. Primary treatments of significant CAS are eversion endarterectomy or endarterectomy with patch plasty. Factors that determine adequate hemodynamic compensation and thereby the clinical consequences of CAS as well as medical and surgical complications of carotid reconstruction surgery likely involve the anatomy of the circle of Willis (CoW), the magnitude of compensatory inter-hemispheric blood flow, and the effectiveness of cerebral microcirculatory blood flow autoregulation. This study aimed to test two hypotheses based on this theory. First, we hypothesized that patients with symptomatic and asymptomatic CAS would exhibit differences in autoregulatory function and inter-hemispheric blood flow. Second, we predicted that anatomically compromised CoW would associate with impaired inter-hemispheric blood flow compensation. We enrolled older adults with symptomatic or asymptomatic internal CAS (>70% NASCET criteria; n = 46) and assessed CoW integrity by CT angiography. We evaluated transient hyperemic responses in the middle cerebral arteries (MCA) after common carotid artery compression (CCC; 10 s) by transcranial Doppler sonography (TCD). We compared parameters reflecting autoregulatory function (e.g., transient hyperemic response ratio [THRR], return to baseline time [RTB], changes of vascular resistance) and inter-hemispheric blood flow (residual blood flow velocity). Our findings revealed that CAS was associated with impaired cerebral vascular reactivity. However, we did not observe significant differences in autoregulatory function or inter-hemispheric blood flow between patients with symptomatic and asymptomatic CAS. Moreover, anatomically compromised CoW did not significantly affect these parameters. Notably, we observed an inverse correlation between RTB and THRR, and 49% of CAS patients exhibited a delayed THRR, which associated with decreased inter-hemispheric blood flow. Future studies should investigate how TCD-based evaluation of autoregulatory function and inter-hemispheric blood flow can be used to optimize surgical techniques and patient selection for internal carotid artery revascularization.

Simplified Transradial Access for Aneurysms Treatment: A Guiding System Using Solo Distal Access Catheter and Anatomical Considerations

OBJECTIVE

The recent shift from transfemoral access to transradial access in neurointervention has led to gaps in guiding systems. We propose a useful guiding system, the solo distal access catheter system without a conventional guiding catheter or a sheath in transradial access for aneurysms treatment. We also assessed the anatomical features required for suitable patient selection.

METHODS

We retrospectively collected data from consecutive patients with aneurysms treated with the solo distal access catheter system at our institution between April 2022 and April 2023, and evaluated the anatomical factors that appeared to affect the procedure.

RESULTS

Of the 20 patients who underwent transradial access, 11 were treated using the solo distal access catheter system, and 10 (90.9%) completed the procedure. No radial artery occlusion was detected. The entry angle of the target vessel ranged from 37° to 139°, and the mean proximal parent artery diameter was 9.34 ± 1.48 mm. A double subclavian innominate curve was observed in 3 of 5 patients whose target vessels were the right common carotid artery.

CONCLUSIONS

Using a solo distal access catheter as a guiding system for treating aneurysm proved effective and feasible with appropriate patient selection. Anatomical assessment of the entry angle of the target vessel, proximal parent artery diameter, and tortuosity may be important factors for the success of this method.

The Extent of Tumor Invasion and Therapeutic Embolization Are Associated with Recurrent Hemorrhage in Patients with External Carotid Artery Blowout Syndrome

PURPOSE

To explore the optimal strategies of therapeutic embolization for patients with carotid blowout syndrome in the external carotid artery (ECA), who may also present with arterial tumor invasion or necrosis extending to the internal carotid artery (ICA) or common carotid artery (CCA).

MATERIALS AND METHODS

The study included 110 patients with ECA blowout between 2005 and 2022. Antecedent cross-sectional imaging features were examined, including tumor size, extent of arterial invasion, and air-containing necrosis. Patients were divided into Groups 1 (n = 53, simultaneous ICA/CCA invasion + ECA therapeutic embolization), 2 (n = 18, simultaneous ICA/CCA invasion + ECA-ICA/CCA therapeutic embolization), and 3 (n = 39, no ICA/CCA invasion + ECA therapeutic embolization). Kaplan-Meier and multivariable Cox regression analyses were performed to evaluate associations of clinical, imaging, and therapeutic embolization characteristics with recurrent bleeding.

RESULTS

Multivariable Cox regression revealed that Group 1 was independently associated with a higher risk of recurrent bleeding than that in Group 2 (adjusted hazard ratio, 6.3; 95% CI, 1.7‒23.4; P = .005) and Group 3 (adjusted hazard ratio, 3.8; 95% CI, 1.8‒8.3; P = .001). In the subgroup with simultaneous ICA/CCA invasion, air-containing necrosis around the ICA/CCA was independently associated with recurrent bleeding after therapeutic embolization of the ECA (adjusted hazard ratio, 5.0; 95% CI, 1.8‒13.6; P = .002).

CONCLUSIONS

In patients with ECA blowout treated with therapeutic embolization, there was a lower risk of recurrent bleeding when the extents of arterial invasion and therapeutic embolization were concordant. Air-containing necrosis around the ICA/CCA was associated with recurrent bleeding, so extensive therapeutic embolization to the ICA/CCA should be evaluated in such patients.

Biomechanical characteristics in the carotid artery: Noninvasive assessment using subharmonic emissions from microbubbles

BACKGROUND

Stroke is closely related to carotid atherosclerotic plaques, which tend to occur in specific parts of the arteries, especially at the bifurcations, and are considered to be caused by biomechanical factors. Quantitative analysis of hemodynamic stress characteristics of the carotid sinus in vivo provides a mechanical basis for the development of atherosclerotic plaque in the carotid sinus. Previous studies found that ultrasound (US) contrast agent microbubbles would vibrate nonlinearly under the excitation of sound pressure, generating subharmonics (transmission fundamental frequency, i.e., f0 and subharmonic frequency at f0 /2), which have the highest sensitivity to pressure changes and exhibit an inverse linear relationship with environmental pressure.

PURPOSE

This study employed subharmonic aided pressure estimation (SHAPE) technology to reflect carotid artery hydrodynamic characteristics in the carotid lumen.

METHODS

From May 2021 to December 2021, this prospective study reviewed a total of 26 normal carotid arteries of 13 participants, all of whom received bilateral carotid artery routine US and SHAPE US examinations. During this study, the lumen of the bilateral distal segment of the common carotid artery (Distal-CCA), carotid artery bifurcation (CAB), and carotid bulb (CB) were scanned section by section from bottom to top in longitudinal and transverse sections. Subsequently, the subharmonic amplitudes in the lumen of normal carotid arteries were collected and analyzed.

RESULTS

This study found that the amplitude of subharmonic amplitude in the carotid was distributed unevenly, with the amplitudes of subharmonic at the CAB being higher. Specifically, the subharmonic gradient of the carotid artery bifurcation apex plane was maximum (9.72 ± 4.31 dB), while the average subharmonic amplitude of the outer lateral layer of the carotid artery was higher (-56.40 ± 6.31 dB) (p < 0.001).

CONCLUSION

The SHAPE technique is capable of indirectly reflecting the pressure changes of vascular system tissues, which may provide a new monitoring method for evaluating mechanical characteristics obviating invasion.

Constituent-based quasi-linear viscoelasticity: a revised quasi-linear modelling framework to capture nonlinear viscoelasticity in arteries

Arteries exhibit fully nonlinear viscoelastic behaviours (i.e. both elastically and viscously nonlinear). While elastically nonlinear arterial models are well established, effective mathematical descriptions of nonlinear viscoelasticity are lacking. Quasi-linear viscoelasticity (QLV) offers a convenient way to mathematically describe viscoelasticity, but its viscous linearity assumption is unsuitable for whole-wall vascular applications. Conversely, application of fully nonlinear viscoelastic models, involving deformation-dependent viscous parameters, to experimental data is impractical and often reduces to identifying specific solutions for each tested loading condition. The present study aims to address this limitation: By applying QLV theory at the wall constituent rather than at the whole-wall level, the deformation-dependent relative contribution of the constituents allows to capture nonlinear viscoelasticity with a unique set of deformation-independent model parameters. Five murine common carotid arteries were subjected to a protocol of quasi-static and harmonic, pseudo-physiological biaxial loading conditions to characterise their viscoelastic behaviour. The arterial wall was modelled as a constrained mixture of an isotropic elastin matrix and four families of collagen fibres. Constituent-based QLV was implemented by assigning different relaxation functions to collagen- and elastin-borne parts of the wall stress. Nonlinearity in viscoelasticity was assessed via the pressure dependency of the dynamic-to-quasi-static stiffness ratio. The experimentally measured ratio increased with pressure, from 1.03 [Formula: see text] 0.03 (mean [Formula: see text] standard deviation) at 80-40 mmHg to 1.58 [Formula: see text] 0.22 at 160-120 mmHg. Constituent-based QLV captured well this trend by attributing the wall viscosity predominantly to collagen fibres, whose recruitment starts at physiological pressures. In conclusion, constituent-based QLV offers a practical and effective solution to model arterial viscoelasticity.

Peri-procedural variables and outcomes of long-period hemodynamic instability after carotid artery angioplasty and stenting

OBJECTIVES

The aim of this study is to identify the peri-procedural risk factors and outcomes of hemodynamic instability (HI) after carotid artery stenting (CAS).

METHODS

A single-center, retrospective study was performed in 168 patients who underwent CAS procedure between September 2017 and September 2020. The presence of HI, as defined by hypertension (systolic blood pressure >160 mmHg), hypotension (systolic blood pressure <90 mmHg), and/or bradycardia (heart rate <60 bpm), was recorded. Long-period HI was defined as persistent HI lasting more than 24 h. Patient demographics, comorbidities, peri-procedural variables, and risk factors were recorded. Clinical outcomes including cerebral hyperperfusion syndrome, hemorrhage, transient ischemic attack (TIA), stroke, myocardial infarction, and mortality within 30 days of the procedure were evaluated. Logistic regression was used to analyze the independent risk factors of long-period HI following CAS.

RESULTS

Among 168 patients (mean age, 68.2 ± 8.3 years; 81.5% male), the frequency of post-procedural long-period HI was noted in 42 patients (25.0%). Male was prone to experience HI (odds ratio, 9.156, p = 0.021). Aggressive inflation pressure (>7 atm) and 5 mm balloon for pre-dilatation were risk factors of long-period HI (OR, 7.372, p = 0.035; OR, 3.527, p = 0.023). Intraoperative peak blood pressure and larger-sized stents remained independent predictors for the development of HI (OR, 1.043, p = 0.027, and OR, 1.973, p = 0.015). Patients with prolonged HI were more likely to suffer TIA and stroke compared to other patients and significant difference was found in the occurrence of TIA (p < 0.05). Non-significance was found in mortality rate and other outcomes.

CONCLUSIONS

CAS-induced HI occurs in a considerable percentage while several peri-procedural variables are determined as independent predictors to develop long-period HI. Patients with prolonged HI are associated with increased risk of neurologic events and thus standardized intervention as well as management of long-period HI are of critical importance during clinical process.

Endovascular transmural access to carotid artery perivascular tissues: safety assessment of a novel technique

BACKGROUND

Recent advances in endovascular devices have allowed access and targeting of perivascular tissues of the peripheral circulation. The perivascular tissues of the cervical and cranial circulations have many important structures of clinical significance, yet the feasibility and safety of such an approach has not been demonstrated.

OBJECTIVE

To evaluate the safety of a novel endovascular transmural approach to target the perivascular tissues of the common carotid artery in swine.

METHODS

A micro-infusion device was positioned in the carotid arteries of three Yorkshire pigs (six carotid arteries in total), and each carotid artery was punctured 10 times in the same location to gain access to the perivascular tissues. Digital subtraction angiography was used to evaluate vessel injury or contrast extravasation. MRI and MR angiography were used to evaluate evidence of cerebral ischemia or vessel injury. Post-mortem tissue analysis was performed to assess the level of extravascular hematoma and intravascular dissection.

RESULTS

None of the tested carotid arteries showed evidence of vessel injury (dissection or perforation) or intravascular thrombosis. MRI performed after repeated puncture was negative for neck hematoma and brain ischemia. Post-mortem tissue analysis of the carotid arteries showed mild adventitial staining with blood, but without associated hematoma and without vessel dissection.

CONCLUSION

Repeated puncture of the carotid artery to gain access to the perivascular tissues using a novel endovascular transmural approach is safe in a swine model. This represents a novel approach to various tissues in close proximity to the cervical and cranial vasculature.

Zero-heat-flux thermometry over the carotid artery in assessment of core temperature in craniotomy patients

Zero-heat-flux core temperature measurements on the forehead (ZHF-forehead) show acceptable agreement with invasive core temperature measurements but are not always possible in general anesthesia. However, ZHF measurements over the carotid artery (ZHF-neck) have been shown reliable in cardiac surgery. We investigated these in non-cardiac surgery. In 99 craniotomy patients, we assessed agreement of ZHF-forehead and ZHF-neck (3M™ Bair Hugger™) with esophageal temperatures. We applied Bland-Altman analysis and calculated mean absolute differences (difference index) and proportion of differences within ± 0.5 °C (percentage index) during entire anesthesia and before and after esophageal temperature nadir. In Bland-Altman analysis [mean (limits of agreement)], agreement with esophageal temperature during entire anesthesia was 0.1 (-0.7 to +0.8) °C (ZHF-neck) and 0.0 (-0.8 to +0.8) °C (ZHF-forehead), and, after core temperature nadir, 0.1 (-0.5 to +0.7) °C and 0.1 (-0.6 to +0.8) °C, respectively. In difference index [median (interquartile range)], ZHF-neck and ZHF-forehead performed equally during entire anesthesia [ZHF-neck: 0.2 (0.1-0.3) °C vs ZHF-forehead: 0.2 (0.2-0.4) °C], and after core temperature nadir [0.2 (0.1-0.3) °C vs 0.2 (0.1-0.3) °C, respectively; all p > 0.017 after Bonferroni correction]. In percentage index [median (interquartile range)], both ZHF-neck [100 (92-100) %] and ZHF-forehead [100 (92-100) %] scored almost 100% after esophageal nadir. ZHF-neck measures core temperature as reliably as ZHF-forehead in non-cardiac surgery. ZHF-neck is an alternative to ZHF-forehead if the latter cannot be applied.

Fat Consumption Attenuates Cortical Oxygenation during Mental Stress in Young Healthy Adults

Mental stress has been associated with cardiovascular events and stroke, and has also been linked with poorer brain function, likely due to its impact on cerebral vasculature. During periods of stress, individuals often increase their consumption of unhealthy foods, especially high-fat foods. Both high-fat intake and mental stress are known to impair endothelial function, yet few studies have investigated the effects of fat consumption on cerebrovascular outcomes during periods of mental stress. Therefore, this study examined whether a high-fat breakfast prior to a mental stress task would alter cortical oxygenation and carotid blood flow in young healthy adults. In a randomised, counterbalanced, cross-over, postprandial intervention study, 21 healthy males and females ingested a high-fat (56.5 g fat) or a low-fat (11.4 g fat) breakfast 1.5 h before an 8-min mental stress task. Common carotid artery (CCA) diameter and blood flow were assessed at pre-meal baseline, 1 h 15 min post-meal at rest, and 10, 30, and 90 min following stress. Pre-frontal cortex (PFC) tissue oxygenation (near-infrared spectroscopy, NIRS) and cardiovascular activity were assessed post-meal at rest and during stress. Mental stress increased heart rate, systolic and diastolic blood pressure, and PFC tissue oxygenation. Importantly, the high-fat breakfast reduced the stress-induced increase in PFC tissue oxygenation, despite no differences in cardiovascular responses between high- and low-fat meals. Fat and stress had no effect on resting CCA blood flow, whilst CCA diameter increased following consumption of both meals. This is the first study to show that fat consumption may impair PFC perfusion during episodes of stress in young healthy adults. Given the prevalence of consuming high-fat foods during stressful periods, these findings have important implications for future research to explore the relationship between food choices and cerebral haemodynamics during mental stress.

Impaired cerebrovascular reactivity correlates with reduced retinal vessel density in patients with carotid artery stenosis: Cross-sectional, single center study

BACKGROUND

The cerebral and retinal circulation systems are developmentally, anatomically, and physiologically interconnected. Thus, we hypothesized that hypoperfusion due to atherosclerotic stenosis of the internal carotid artery (ICA) can result in disturbances of both cerebral and retinal microcirculations. We aimed to characterize parameters indicating cerebrovascular reactivity (CVR) and retinal microvascular density in patients with ICA stenosis, and assess if there is correlation between them.

METHODS

In this cross-sectional study the middle cerebral artery (MCA) blood flow velocity was measured by transcranial Doppler (TCD) and, simultaneously, continuous non-invasive arterial blood pressure measurement was performed on the radial artery by applanation tonometry. CVR was assessed based on the response to the common carotid artery compression (CCC) test. The transient hyperemic response ratio (THRR) and cerebral arterial resistance transient hyperemic response ratio (CAR-THRR) were calculated. Optical coherence tomography angiography (OCTA) was used to determine vessel density (VD) on the papilla whole image for all (VDP-WIall) and for small vessels (VDP-WIsmall). The same was done in the peripapillary region: all (VDPPall), and small (VDPPsmall) vessels. The VD of superficial (VDMspf) and deep (VDMdeep) macula was also determined. Significance was accepted when p<0.05.

RESULTS

Twenty-four ICA stenotic patients were evaluated. Both CVR and retinal VD were characterized. There was a significant, negative correlation between CAR-THRR (median = -0.40) and VDPPsmall vessels (median = 52%), as well as between VDPPall vessels (median = 58%), and similar correlation between CAR-THRR and VDP-WIsmall (median = 49.5%) and between VDP-WIall (median = 55%).

CONCLUSION

The significant correlation between impaired cerebrovascular reactivity and retinal vessel density in patients with ICA stenosis suggests a common mechanism of action. We propose that the combined use of these diagnostic tools (TCD and OCTA) helps to better identify patients with increased ischemic or other cerebrovascular risks.

B-mode ultrasound characteristics of carotid plaques in symptomatic and asymptomatic patients with low-grade stenosis

Carotid plaque features assessed using B-mode ultrasound can be useful for the prediction of cerebrovascular symptoms. Therefore, the aim of this retrospective study was to determine the ability of ultrasound B-mode imaging to differentiate between carotid plaques causing less than 50% stenosis in symptomatic and asymptomatic patients. A dataset of 1,593 patients with carotid disease who underwent carotid ultrasound between 2016 and 2021 was evaluated retrospectively between January and April of 2022. A total of 107 carotid plaques from 35 symptomatic and 52 asymptomatic patients causing low-grade stenosis on B-mode images were included in the analysis. Chi-square, independent t-test and Mann-Whitney U test were used to compare the variables. There was a significant association between hypertension and the presence of cerebrovascular symptoms (p = 0.01). Predominantly hypoechoic and hyperechoic carotid plaque were significantly associated with the presence and absence of cerebrovascular symptoms, respectively (predominantly hypoechoic: p = 0.01; predominantly hyperechoic: p = 0.02). Surface irregularity was significantly associated with the presence of cerebrovascular symptoms (p = 0.02). There is was a significant difference in the carotid plaque length and area between the symptomatic and asymptomatic patients (plaque length: symptomatic median 9 mm, interquartile range [IQR] 6 mm; asymptomatic median 6 mm, IQR 4.5 mm, p = 0.01; plaque area: symptomatic median 24 mm, IQR 30 mm; asymptomatic median 14 mm, IQR 17 mm, p = 0.01); however, this difference was not significant for plaque thickness (p = 0.55), or common carotid artery intima-media thickness (p = 0.7). Our findings indicate that hypertension patients with predominantly hypoechoic carotid plaques and plaques with an irregular surface are associated with the presence of cerebrovascular symptoms. In addition, the carotid plaques in symptomatic patients were longer and larger compared to asymptomatic patients.

An analytical method informed by clinical imaging data for estimating outlet boundary conditions in computational fluid dynamics analysis of carotid artery blood flow

Stroke occur mainly due to arterial thrombosis and rupture of cerebral blood vessels. Previous studies showed that blood flow-induced wall shear stress is an essential bio marker for estimating atherogenesis. It is a common practice to use computational fluid dynamics (CFD) simulations to calculate wall shear stress and to quantify blood flow. Reliability of predicted CFD results greatly depends on the accuracy of applied boundary conditions. Previously, the boundary conditions were estimated by varying values so that they matched the clinical data. It is applicable upon the availability of clinical data. Meanwhile, in most cases all that can be accessed are arterial geometry and inflow rate. Consequently, there is a need to devise a tool to estimate boundary values such as resistance and compliance of arteries. This study proposes an analytical framework to estimate the boundary conditions for a carotid artery based on the geometries of the downstream arteries available from clinical images.

Sodium tanshinone IIA sulfonate ameliorates neointima by protecting endothelial progenitor cells in diabetic mice

BACKGROUND

Endothelial progenitor cells (EPCs) transplantation is one of the effective therapies for neointima associated with endothelial injury. Diabetes impairs the function of EPCs and cumbers neointima prevention of EPC transplantation with an ambiguous mechanism. Sodium Tanshinone IIA Sulfonate (STS) is an endothelium-protective drug but whether STS protects EPCs in diabetes is still unknown.

METHODS

EPCs were treated with High Glucose (HG), STS, and Nucleotide-binding Domain-(NOD) like Receptor 3 (NLRP3), caspase-1, the Receptor of Advanced Glycation End products (AGEs) (RAGE) inhibitors, Thioredoxin-Interacting Protein (TXNIP) siRNA, and EPC proliferation, differentiation functions, and senescence were detected. The treated EPCs were transplanted into db/db mice with the wire-injured Common Carotid Artery (CCA), and the CD31 expression and neointima were detected in the CCA inner wall.

RESULTS

We found that STS inhibited HG-induced expression of NLRP3, the production of active caspase-1 (p20) and mature IL-1β, the expression of catalase (CAT) cleavage, γ-H2AX, and p21 in EPCs. STS restored the expression of Ki67, CD31 and von Willebrand Factor (vWF) in EPCs; AGEs were found in the HG-treated EPCs supernatant, and RAGE blocking inhibited the expression of TXNIP and the production of p20, which was mimicked by STS. STS recovered the expression of CD31 in the wire-injured CCA inner wall and the prevention of neointima in diabetic mice with EPCs transplantation.

CONCLUSION

STS inhibits the aggravated neointima hyperplasia by protecting the proliferation and differentiation functions of EPC and inhibiting EPC senescence in diabetic mice. The mechanism is related to the preservation of CAT activity by inhibiting the RAGE-TXNIP-NLRP3 inflammasome pathway.

Carotid Plaque Score for Stroke and Cardiovascular Risk Prediction in a Middle-Aged Cohort From the General Population

Background We aimed to explore the predictive value of the carotid plaque score, compared with the Systematic Coronary Risk Evaluation 2 (SCORE2) risk prediction algorithm, on incident ischemic stroke and major adverse cardiovascular events and establish a prognostic cutoff of the carotid plaque score. Methods and Results In the prospective ACE 1950 (Akershus Cardiac Examination 1950 study), carotid plaque score was calculated with ultrasonography at inclusion in 2012 to 2015. The largest plaque diameter in each extracranial segment of the carotid artery on both sides was scored from 0 to 3 points. The sum of points in all segments provided the carotid plaque score. The cohort was followed up by linkage to national registries for incident ischemic stroke and major adverse cardiovascular events (nonfatal ischemic stroke, nonfatal myocardial infarction, and cardiovascular death) throughout 2020. Carotid plaque score was available in 3650 (98.5%) participants, with mean±SD age of 63.9±0.64 years at inclusion. Only 462 (12.7%) participants were free of plaque, and and 970 (26.6%) had a carotid plaque score of >3. Carotid plaque score predicted ischemic stroke (hazard ratio [HR], 1.25 [95% CI, 1.15-1.36]) and major adverse cardiovascular events (HR, 1.21 [95% CI, 1.14-1.27]) after adjustment for SCORE2 and provided strong incremental prognostic information to SCORE2. The best cutoff value of carotid plaque score for ischemic stroke was >3, with positive predictive value of 2.5% and negative predictive value of 99.3%. Conclusions The carotid plaque score is a strong predictor of ischemic stroke and major adverse cardiovascular events, and it provides incremental prognostic information to SCORE2 for risk prediction. A cutoff score of >3 seems to be suitable to discriminate high-risk subjects. Registration Information clinicaltrials.gov. Identifier: NCT01555411.

Long-term vascular dysfunction in Kawasaki disease: systematic review and meta-analyses

BACKGROUND

Long-term physiological dysfunction in coronary/systemic vasculature may persist in individuals with Kawasaki disease even in the absence of coronary artery abnormalities. We perform a systematic review and meta-analyses of studies assessing long-term vascular function in Kawasaki disease.

METHODS

PubMed, Embase, and Web of Science databases were searched for relevant literature published till May 2021. Patients with Kawasaki disease were included as cases and healthy age/sex-matched individuals as controls. Newcastle Ottawa Scale was used to assess the study quality. Outcome measures were differences in markers of vascular function 1 year after diagnosis of Kawasaki disease. Data were analysed using Review Manager software. Comprehensive meta-analysis software was used for meta-regression. To assess the certainty of evidence, GRADE Profiler software was utilised.

RESULTS

Of 2280 citations, 49 case-control studies (comprising 2714 cases and 2118 controls) were included for data synthesis. Decreased flow-mediated dilatation [3.83, 95%CI 0.94-6.72] and increased pulse-wave velocity [39.34 cm/sec, 95%CI 20.86-57.83], arterial stiffness [0.35, 95%CI 0.11-0.59], and common carotid artery intima-media thickness were noted in patients with Kawasaki disease. No significant difference was observed for nitroglycerine-mediated dilatation and endothelial peripheral artery tonometry (endo-PAT). Significant inter-study heterogeneity was observed for flow-mediated dilatation, arterial stiffness, carotid artery intima-media thickness, and endo-PAT. The GRADE evidence was of 'very low quality' for all outcome measures except 'moderate quality' for pulse-wave velocity.

CONCLUSIONS

Evidence suggests the presence of long-term endothelial dysfunction in patients with Kawasaki disease even in the absence of coronary artery abnormalities. Avoidance of development of other cardiovascular risk factors seems prudent in patients with Kawasaki disease.

Reliability of carotid-femoral arterial waveforms for the derivation of ultra-short term heart rate variability in injured British servicemen: An inter-rater reliability study

In this study, the comparative precision of carotid versus femoral arterial waveforms to measure ultra-short term heart rate variability (HRVUST) following traumatic injury was investigated for the first time. This was an inter-rater reliability study of 50 British servicemen (aged 23-44 years) with non-acute combat-related traumatic injury (CRTI). Paired continuous arterial waveform data for HRVUST analysis, were simultaneously sampled at the carotid and femoral arterial sites (14-16 seconds) during pulse wave velocity (PWV) measurement. HRVUST was reported as the root mean square of the successive differences (RMSSD). Following the determination of the superior sampling site (carotid versus femoral), the blinded inter-rater agreement in RMSSD for the preferred site was quantified using the Intra-class Correlation Coefficient (ICC) and the Bland-Altman plot. The mean age of participants was 34.06±4.88 years. The femoral site was superior to the carotid site with a significantly higher number of reliable signals obtained (Fisher's Exact test; p<0.001). The inter-rater agreement in femoral-derived RMSSD was excellent [ICC 0.99 (95%CI: 0.994-0.997)] with a moderate level of agreement (mean difference [bias]: 0.55; 95% CI: -0.13-1.24 ms). In this study, we demonstrated that the femoral artery is a more reliable site than the carotid artery for HRVUST measurement and post-trauma risk stratification following CRTI.

Reduced reward responsiveness in treatment resistant depression of middle-aged adults: Association with carotid artery stiffness and tetrahydrobiopterin

Nearly one third of the population diagnosed with major depressive disorder (MDD) fail to respond to two or more antidepressant drugs of adequate dose and duration. This necessitates identification of confounding psychological and physiological factors that could contribute to treatment resistant depression (TRD). The present longitudinal study investigated the influence of behavioural inhibition system (BIS) and behavioural approach system (BAS) in treatment resistance. Further, the association of depression severity with physiological factors contributing to arterial stiffness was also investigated. Baseline data was acquired from 101 middle-aged (36-56 years) patients on immediate diagnosis with MDD using DSM-V criteria. Follow ups were conducted at 06 months and 12 months during treatment. Psychological assessment battery at baseline and follow ups comprised of Hamilton depression rating (HAM-D) for depression severity, WHODAS-2 and BIS-BAS score. Atherosclerosis and central arterial stiffness were measured by intima-media thickness of internal carotid artery and brachial-ankle pulse wave velocity. Physiological factors influencing central vascular function viz., body-mass index, estimated glomerular filtration rate, HbA1c, central systolic and diastolic blood pressure, heart rate and tetrahydrobiopterin were also investigated. Our results show lower reward responsiveness (BAS-RR) and higher BIS scores in TRD patients along with differentially higher intima-media thickness of left internal carotid artery. Higher depression severity at all stages of the study was correlated with lower tetrahydrobiopterin and BAS-RR scores. We, therefore, suggest that vascular depression resulting due to increased intima-media thickness of left carotid artery and lower tetrahydrobiopterin could be contributing factors for treatment resistance in middle-aged MDD patients.

The Carotid-Hyoid Topography Is Variable

Background and Objectives: The carotid bifurcation (CB) is presented in most anatomy textbooks as having a unique location at the upper margin of the thyroid cartilage. Although a number of case reports have provided evidence of the possibility of carotid artery location either lateral or medial to the greater hyoid horn, these reports have not established specific anatomic possibilities and prevalences. Materials and Methods: We retrospectively analysed a batch of 147 CT angiograms for 12 types of carotid-hyoid relationships and classified the bilateral combination possibilities of these types. Results: In 168/294 sides there were no carotid-hyoid relationships. Type I, external carotid artery (ECA) medial to the greater horn of the hyoid bone (GHHB), was observed in 0.34%; type II, internal carotid artery (ICA) medial to GHHB, in 0.34%; type III, ICA and ECA medial to GHHB, in 1.02%; type IV, common carotid artery (CCA) medial to GHHB, in 1.02%; type V, CB medial to GHHB, in 0.34%; type VI, ECA lateral to GHHB, in 20.41%; type VII, ICA lateral to GHHB, was not recorded; type VIII, ECA and ICA lateral to GHHB, in 3.74%; type IX, CCA lateral to GHHB, in 8.5%; type X, CB lateral to GHHB, in 6.46%; type XI, ECA lateral and ICA medial to GHHB, in 0.34%; and type XII, ICA lateral and ECA medial to GHHB, in 0.34%. Bilateral symmetry was found in 70.74% of cases, including the null types without carotid-hyoid relationships as well as types IV, VI, VIII, IX, and X. There was a highly significant association between the left and right variants of the carotid-hyoid relationship. Conclusions: Mechanical compression of the hyoid bone on the carotid arteries has various undesirable effects on the ICA and cerebral circulation. Underlying these are several variational anatomical patterns of carotid-hyoid relationships, which can be accurately documented on CT angiograms. A case-by-case anatomical study is better than assuming the carotid anatomy learned from textbooks.

Highly reproducible rat arterial injury model of neointimal hyperplasia

Models of arterial injury in rodents have been invaluable to our current understanding of vessel restenosis and play a continuing role in the development of endovascular interventions for cardiovascular disease. Mechanical distention of the vessel wall and denudation of the vessel endothelium are the two major modes of vessel injury observed in most clinical pathologies and are critical to the reproducible modelling of progressive neointimal hyperplasia. The current models which have dominated this research area are the mouse wire carotid or femoral injury and the rat carotid balloon injury. While these elicit simultaneous distension of the vessel wall and denudation of the luminal endothelium, each model carries limitations that need to be addressed using a complementary injury model. Wire injuries in mice are highly technical and procedurally challenging due to small vessel diameters, while rat balloon injuries require permanent blood vessel ligation and disruption of native blood flow. Complementary models of vascular injury with reproducibility, convenience, and increased physiological relevance to the pathophysiology of endovascular injury would allow for improved studies of neointimal hyperplasia in both basic and translational research. In this study, we developed a new surgical model that elicits vessel distention and endothelial denudation injury using sequential steps using microforceps and a standard needle catheter inserted via arteriotomy into a rat common carotid artery, without requiring permanent ligation of branching arteries. After 2 weeks post-injury this model elicits highly reproducible neointimal hyperplasia and rates of re-endothelialisation similar to current wire and balloon injury models. Furthermore, evaluation of the smooth muscle cell phenotype profile, inflammatory response and extracellular matrix within the developing neointima, showed that our model replicated the vessel remodelling outcomes critical to restenosis and those becoming increasingly focused upon in the development of new anti-restenosis therapies.

Breast Cancer Brain Metastases: Implementation and Characterization of a Mouse Model Relying on Malignant Cells Inoculation in the Carotid Artery

Breast cancer (BC) brain metastases (BCBM) is a severe condition frequently occurring in the triple-negative subtype. The study of BCBM pathogenesis and treatment has been hampered by the difficulty in establishing a reliable animal model that faithfully recapitulates the preferential formation of brain metastases. The injection of BC cells in the carotid artery of mice has been proposed but the procedure is challenging, with the metastatic pattern being scarcely characterized. In this work, we thoroughly describe an improved procedure, highlighting the tricks and challenges of the process, and providing a characterization of the brain and peripheral metastatic pattern at the cellular and molecular level. Triple-negative BC (4T1) cells were inoculated in the common carotid artery of BALB/c mice. Brains and peripheral organs were harvested at 7-14 days for the histological characterization of the metastases' pattern and the immunofluorescence analysis of specific markers. With our surgical procedure, both mouse death and procedure-associated weight loss were negligible. Brain metastases mostly occurred in the hippocampus, while sparse peripheral lesions were only detected in the lungs. Brain-colonizing BC cells presented proliferative (Ki-67) and epithelial (pan-cytokeratin and tomato lectin) features, which account for metastases' establishment. The presented surgical approach constitutes an important and reliable tool for BCBM studies.