Section Of Artery Research Articles

Influence of Forced Field on Blood Flow in an Overlapping Stenosed Arterial Section

This article presents the theoretical analysis of the nonlinear behavior of the blood flow through an angled arterial segment with overlapping stenosis. A mathematically created time-variant stenosis emerges from the formation of arterial narrowing brought on by atheroma. An elastic cylindrical tube with a moving wall is used to represent the artery, and the Casson liquid is used to simulate blood that flows through it. The nonlinear elements that arise in the equations, govern blood flow are taken into account. The impact of the pulsatile pressure gradient that caused by the regular heartbeat on the flow process in the stenosed artery is demonstrated mathematically. By employing the boundary conditions, the present analytical technique can easily compute the velocity profiles, wall shear stress, and flow resistivity. To carry out a systematic quantitative study, the desired quantities are numerically computed. The results are graphically presented in the discussion section. They provide an overview of how the degree of stenosis and the malleability of the artery wall influence blood flow abnormalities. The application of the current model is adequately justified by many significant conclusions.

Biomimetic porphyrin-lipid nanoparticles - novel nanoscale theranostics for multimodal imaging and therapy in atherosclerotic cardiovascular disease

Abstract Background High-density lipoprotein (HDL) mimetic nanoagents have unrealized potential for atherosclerosis theranostics. Porphyrin-lipid HDL mimetic nanoparticles (Por-HDL-NPs) incorporate a porphyrin-lipid conjugate which permits near infrared fluorescence imaging and positron emission tomography (PET) through chelation of Copper-64 (64Cu). The outer shell contains apolipoprotein A-I mimetic peptide R4F designed to interact with scavenger receptor class B type I (SR-BI), enabling macrophage-targeting and therapeutic effects. Purpose To investigate the multimodal imaging, macrophage-targeting and therapeutic properties of Por-HDL-NPs and applications in atherosclerotic cardiovascular disease. Methods In vitro, the cholesterol efflux capacity of PBS (control), reconstituted HDL (rHDL) and Por-HDL-NPs was determined in immortalized bone marrow-derived macrophages (iBMDMs) loaded with [³H]-cholesterol. Real-time quantitative PCR (RT-qPCR) assessed mRNA levels of inflammatory mediators. ELISAs and Western blotting measured changes in protein levels. Apolipoprotein (Apo)e-/- mice were fed high-cholesterol diet (HCD) for 6 weeks, for early-stage plaque, and 13 weeks for the unstable plaque model in which two partial stenoses were made in the right carotid artery. PET and fluorescence (IVIS, flow cytometry, microscopy) imaging identified Por-HDL-NPs in plaques, circulating and aortic cells. Histological techniques assessed plaque area and composition in aortic sinus and carotid artery sections. Results Por-HDL-NPs were internalized by iBMDMs, visualized via fluorescence microscopy and flow cytometry. Por-HDL-NPs increased cholesterol efflux (49%, P<0.05), compared to rHDL. Por-HDL-NPs reduced macrophage mRNA levels of Il-1b (88%), Il-18 (54%) and Ccl5 (75%), and protein secretion of IL-1β (69%) and CCL5 (82%), P<0.05. Por-HDL-NPs suppressed inflammasome components Nlrp3 (69%) and Asc (36%), and activation of inflammatory transcription factor p65-NF-κB (53%), P<0.05. SR-BI siRNA knockdown and methyl-β-cyclodextrin, revealed that the anti-inflammatory properties of Por-HDL-NPs were independent of SR-BI and cholesterol efflux. In Apoe-/- mice, PET imaging showed 64Cu-Por-HDL-NPs localized in hearts and could detect increases in plaque size over time with HCD feeding. Por-HDL-NP fluorescence was detected within aortic sinus and unstable carotid plaques, co-localized with CD68+ macrophages. Por-HDL-NP-treated mice had smaller early-stage (22%) and unstable plaques (52%) than control PBS-treated mice, P<0.05. Por-HDL-NP mice had fewer circulating (32%) and aortic monocytes (81%), and a reduction in aortic arch Rela (26%), P<0.05. Conclusions Por-HDL-NPs present as potential nanoscale theranostics for atherosclerotic cardiovascular disease. Por-HDL-NPs can detect plaques using multiple imaging modalities and exhibit atheroprotective effects.Atherosclerosis imaging with Por-HDL-NPs

Genesis of Intimal Thickening Due to Hemodynamical Shear Stresses.

This paper investigates intimal growth in arteries, induced by hemodynamical shear stress, through finite element simulation using the FEniCS computational environment. In our model, the growth of the intima depends on cross section geometry and shear stress. In this work, the arterial wall is modeled as three distinct layers: the intima, the media, and the adventitia, each with different mechanical properties. We assume that the cross section of the vessel does not change in the axial direction. We further assume that the blood flow is steady, non-turbulent, and unidirectional. Blood flow induces shear stress on the endothelium and stimulates the release of Platelet Derived Growth Factor (PDGF) which drives the growth. We simulate intimal growth for three distinct arterial cross section geometries. We show that the qualitative nature of intimal thickening varies depending on arterial geometry. For cross section geometries that are annular, the growth of the intima is uniform in the angular direction, and the endothelium stays circular as the intima grows. For non-annular cross section geometries, thicker intimas grow more compared to thinner ones, shear stress and intimal thickening are negatively correlated with the distance from the flow center, where the flow velocity is maximal. Over time, the maxima and minima of the curvature increase and decrease respectively, the PDGF concentration increases, and the lumen becomes more polygonal. The model provides a framework for coupling hemodynamics simulations to mathematical descriptions of atherosclerosis, both of which have been modeled separately in great detail.

Modeling Arterial Blood Flow under Stenosis: A Comparative Study of Newtonian and Carreau-Yasuda Non-Newtonian Approaches

This study investigates the simulation of blood flow within arteries experiencing stenosis using both Newtonian and non-Newtonian models. The Newtonian model employs standard fluid dynamics assumptions, while the non-Newtonian Carreau-Yasuda model accounts for the unique viscoelastic properties of blood, providing a more accurate representation of its flow behavior under various shear rates. By utilizing COMSOL Multiphysics, the simulations are conducted with parameters including blood velocity, viscosity, and pressure in normal and narrowed artery conditions. Results reveal that while the Newtonian model predicts general flow patterns, it lacks the precision needed to reflect the complexities of blood behavior in stenosed regions. Conversely, the Carreau-Yasuda model demonstrates enhanced accuracy by capturing viscosity variations and pressure differentials, particularly in the narrowed artery sections, showing the significance of non-Newtonian characteristics in modeling blood flow. These findings underscore the potential of non-Newtonian models in improving diagnostic and therapeutic approaches for vascular conditions.

New Insights into the Pathophysiology of Coronary Artery Aneurysms.

Coronary aneurysms are typically defined as sections of a coronary artery where the diameter is more than 1.5 times that of an adjacent normal segment. In rare circumstances, these aneurysms can become exceedingly large, leading to the classification of giant coronary artery aneurysms. Despite their occurrence, there is no clear consensus on the precise definition of giant coronary artery aneurysms, and their etiology remains somewhat ambiguous. Numerous potential causes have been suggested, with atherosclerosis being the most prevalent in adults, accounting for up to 50% of cases. In pediatric populations, Kawasaki disease and Takayasu arteritis are the primary causes. Although often discovered incidentally, coronary artery aneurysms can lead to severe complications. These complications include local thrombosis, distal embolization, rupture, and vasospasm, which can result in ischemia, heart failure, and arrhythmias. The optimal approach to medical, interventional, or surgical management of these aneurysms is still under debate and requires further clarification. This literature review aims to consolidate current knowledge regarding coronary artery aneurysms' pathophysiology, emphasizing their definition, causes, complications, and treatment strategies. Recent research has begun to explore the molecular mechanisms involved in the formation and progression of coronary artery aneurysms. Various molecules, such as matrix metalloproteinases (MMPs), inflammatory cytokines, and growth factors, play crucial roles in the degradation of the extracellular matrix and the remodeling of vascular walls. Elevated levels of MMPs, particularly MMP-9, have been associated with the weakening of the arterial wall, contributing to aneurysm development. Inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α) and interleukins (IL-1β and IL-6) have been implicated in promoting inflammatory responses that further degrade vascular integrity. Additionally, growth factors such as vascular endothelial growth factor (VEGF) may influence angiogenesis and vascular remodeling processes. Understanding these molecular pathways is essential for developing targeted therapies aimed at preventing the progression of coronary artery aneurysms and improving patient outcomes.

Abstract P444: Radial pulse wave velocity measurement method with dual ultrasound probe for low power wearables

Background: Wearables for continuous blood pressure monitoring hold the promise to drastically improve hypertension management, but current solutions still lack the required accuracy. Ultrasounds might be able to overcome this limitation because they can measure quantitative parameters highly correlated with blood pressure, such as artery diameter, its motion over the cardiac cycle (AWM) and local pulse wave velocity (PWV). Here we validate radial PWV measurement with an ultrasound method that can be integrated in low power wearables. Methods: The study was conducted on 8 healthy subjects at rest. The ultrasound scan was performed on the left arm with a research scanner and two linear probes held at a fixed distance and used to image two transversal sections of the radial artery at 11.5 kHz for 10 seconds. The first image of each section is segmented to identify the artery walls and AWM is reconstructed by tracking the phase of the wall echo. PWV is extracted from the delay of artery wall motion waveforms on the 2 sections. Reference values of carotid-radial PWV were acquired with Diatecne PulsePen ETT immediately after the ultrasound acquisition on the same arm. Results: The estimate and accuracy of the local radial PWV of proposed ultrasound method is in agreement with the reference carotid-radial PWV obtained with the tonometer. The accuracy of the methods is estimated from the beat-to-beat variability of the delays between the waves used for the estimates. Conclusions: The proposed method allows to measure the radial pulse wave within shorter distances compatible with integration in wearables. Leveraging TDK ultrasound MEMS platform, this paves the route for low power wearable for continuous cardio-vascular monitoring.

The morphology of internal elastic lamina corrugations in arteries under physiological conditions

Background: In elastic and resistance arteries, an elastin-rich membrane, the Internal Elastic Lamina (IEL), separates the tunica intima from the underlying tunica media. The IEL often appears wrinkled or corrugated in histological images. These corrugations are sometimes ascribed to vessel contraction ex vivo, and to fixation artifacts, and therefore regarded as not physiologically relevant. We examine whether the IEL remains corrugated even under physiological conditions.Methods: The diameters of carotid arteries of anesthetized pigs were measured by ultrasound. The arteries were then excised, inflated within a conical sleeve, fixed, and imaged by confocal microscopy. The conical sleeve allows fixing each artery across a wide range of diameters which bracket its ultrasound diameter. Thus the study was designed to quantify how corrugations change with diameter for a single artery, and test whether corrugations exist when the fixed artery matches the ultrasound diameter.Results: At diameters below the ultrasound diameter (i.e. when the artery was constricted as compared to ultrasound conditions), the IEL corrugations were found to decrease significantly with increasing diameter, but not fully flatten at the ultrasound diameter. The contour length of the IEL was found to be roughly 10% larger than the circumference of the artery measured by ultrasound. The physiological diameter is likely to be even smaller than the ultrasound diameter since ultrasound was conducted with the animal under general anesthesia which leads to vasodilation, suggesting a higher level of corrugation under physiological conditions. For arterial cross sections constricted below the ultrasound diameter, the IEL contour length decreased roughly with the square root of the diameter.Conclusion: The primary conclusions of this study are: a) the IEL is corrugated when the artery is constricted and flattens as the artery diameter increases, b) the IEL is corrugated under physiological conditions and has a contour length at least 10% more than the physiological arterial diameter, and c) the IEL despite being relatively stiffer than the surrounding arterial layers, does not behave like an inextensible membrane.

Computed Tomography Angiography as a Method for Diagnosing Intracavitary Coronary Arteries.

The intracavitary coronary arteries (ICCA) course is a rare phenomenon, where the segments of the coronary artery go through the atria or ventricles of the heart. In the past, these changes were incidentally detected during invasive diagnostic procedures for other reasons, as well as during postmortem examinations. As the use of multidetector computed tomography angiography (CTA) becomes more widespread, it has emerged that the incidence of ICCA has been underestimated. We present images from two coronary computed tomography angiography cases, which document the existence of ICCA in patients with non-specific chest pain. In the first case, in a 66-year-old woman, in addition to confirming coronary artery disease without significant stenosis (CAD-RADS 2-category 2 in the coronary-artery-disease-reporting and data system), the course of the middle section of the right coronary artery (RCA) in the lumen of the right atrium was demonstrated. In the second case, in a 47-year-old man in whom the presence of atherosclerotic lesions in the coronary arteries was excluded (CAD-RADS 0), the course of the distal segment of the left anterior descending (LAD) was found in the lumen of the apical layers of the right ventricle. To sum up, it should be stated that coronary CTA is a non-invasive diagnostic method that allows for visualization of the ICCA. In coronary CTA performed for indications consistent with the guidelines of scientific societies, attention should also be paid to the possible intracavitary course of the coronary arteries. The identification of such a course of the coronary arteries may be useful when preparing the patient for potential future invasive procedures involving the cardiac cavities.

Hybrid interventions on distal sections of the main arteries in extended chronic occlusions of the superficial femoral artery in patients with critical limb ischemia

AbstractBackground. Over two thirds of patients with CLI present with SFA disease, often a long CTOwith patent proximal popliteal artery and extensive occlusive lesions in the crural vessels. Westudied a series of hybrid interventions to treat this multilevel disease as an alternative to conventionalapproach.Aim. To improve the results of revascularization of the lower limb in cases of extended occlusionof the SFA in combination with crural runoff.Materials and Methods: A total of 40 patients (25% women; mean age 69.5 years), all with Rutherfordclass 5-6 disease, were included in the study. Angiography showed long (>200 mm) SFA CTOin all cases (100%) accompanied by CTO of distal popliteal artery (n=9; 22.5%); all crural arteries(n=26; 65%) or all crural arteries but the peroneal (n=7; 17.5%).We performed femoropopliteal bypass with autologous vein in all patients (100%) followed byballoon angioplasty of distal popliteal and/or crural arteries done either on the same day (n=22;55%) or 2-14 days later (n=18; 45%). Direct angiosomic revascularization was achieved in 36 patients(90%).We used a series of 46 consecutive patients who underwent femoral tibial bypass as historic control.Results. The 30-day mortality and graft failure rate were 2.5% vs 4.3% (p>0.05) and 5% vs 13%(p<0.05) after hybrid and tibial bypass interventions, respectively.At 1 year the primary patency of bypass and amputation-free survival were 77.7% (95% CI 61.7-93.7) vs 57.1% (95% CI 42.9-71.3) and 82.1% (95% CI 66.8-97.4) vs 69.6% (95% CI 56.1-83.1) afterhybrid intervention and tibial bypass, respectively (all non-significant).Conclusions. Compared to femoral tibial bypass, a hybrid intervention comprised of a bypass to apatent popliteal artery and subsequent crural angioplasty decreased the early failure rate withoutany negative effect on the long-term outcomes in CLI patients with long SFA CTO and extensiverunoff disease.

Hemodynamic characteristics of blood flow in an inclined overlapped stenosed arterial section

This work presents a theoretical analysis of the non-linear behavior of blood flow along an angled arterial section with overlapping stenosis. An elastic cylindrical tube with a moving wall is used to represent the artery, and a Casson liquid is used to simulate blood flowing through it. The nonlinear equations that govern blood flow are taken into account. The influence of the pulsatile pressure gradient caused by the regular heartbeat on the flow process in the stenosed artery is demonstrated mathematically. The current analytical method can compute the wall shear stress, flow resistivity, and velocity profiles with mild stenosis assumption by applying the boundary conditions. Numerical calculations of the desired quantities are carried out systematically. They provide an overview of how the degree of stenosis and the malleability of the artery wall influence blood flow abnormalities. Concerning the height of stenosis, the surface shear stress and the resistivity to flow increase together with an increase in the proclivity angle.

Optical frequency domain imaging (OFDI) represents a novel technique for the diagnosis of giant cell arteritis

Background/ObjectivesGiant cell arteritis (GCA) is an inflammatory vascular disease in which prompt and accurate diagnosis is critical. The efficacy of temporal artery biopsy (TAB) is limited by ‘skip’ lesions and a delay in histological analysis. This first-in-man ex-vivo study aims to assess the accuracy of optical frequency domain imaging (OFDI) in diagnosing GCA.Subjects/Methods29 TAB samples of patients with suspected GCA were submerged in 0.9% sodium chloride and an OFDI catheter was passed through the lumen to create cross-sectional images prior to histological analysis. The specimens were then preserved in formalin for histological examination. Mean intimal thickness (MIT) on OFDI was measured, and the presence of both multinucleate giant cells (MNGCs) and fragmentation of the internal elastic lamina (FIEL) was assessed and compared with histology, used as the diagnostic gold standard.ResultsMIT in patients with/without histological evidence of GCA was 0.425 mm (±0.43) and 0.13 mm (±0.06) respectively compared with 0.215 mm (±0.09) and 0.135 mm (±0.07) on OFDI. MIT measured by OFDI was significantly higher in patients with histologically diagnosed arteritis compared to those without (p = 0.0195). For detecting FIEL and MNGCs, OFDI had a sensitivity of 75% and 28.6% and a specificity of 100% and 77.3% respectively. Applying diagnostic criteria of MIT > 0.20 mm, or the presence of MNGCs or FIEL, the sensitivity of detecting histological arteritis using OFDI was 91.4% and the specificity 94.1%.ConclusionsOFDI provided rapid imaging of TAB specimens achieving a diagnostic accuracy comparable to histological examination. In-vivo imaging may allow imaging of a longer arterial section.

CFD simulation of arterial hypotension in a left anterior coronary artery section with potential clinical relevance

ABSTRACT Atherosclerosis is a complex cardiovascular condition characterised by the buildup of fatty deposits, known as plaques, on the inner walls of arteries. Stenosis occurs when the narrowing of an artery becomes particularly pronounced due to the accumulation of plaque. This narrowed lumen leads to significant pressure drops during blood flow, which may lead to decreased blood flow to the target tissues. The current study focuses on conducting computational fluid dynamic (CFD) simulations of blood flow within a linear segment of the LAD (Left anterior descending) coronary artery, subject to differing degrees of atherosclerotic stenosis. The simulations are performed using COMSOL Multiphysics 5.6®. The study has computed pressure drops by considering the laminar flow of blood as a two-phase non-Newtonian fluid. The rheological characteristics have been modelled using the Carreau Yasuda model. It considers varying stenosis severities ranging from 10% to 90%, coupled with blood velocities spanning from 0.07 m/s to 0.2 m/s. Additionally, the findings have been compared to results generated using the Power Law model and Casson-Papanastasiou model for blood rheology. The pressure drop within the stenosed section has been correlated with stenosis percentages through power law models.

POST-TRAUMATIC BRACHIAL ARTERY PSEUDOANEURYSM (CLINICAL CASE)

We present a clinical case of treatment of pseudoaneurysm of the right brachial artery. The cause of the pseudoaneurysm was a gunshot wound to the right shoulder. An aneurysmectomy, endarterectomy, and autovenous prosthetic repair of the right brachial artery were performed. Histological examination revealed thrombotic masses, a fragment of the vessel wall with fibroblast proliferation, hemorrhages, focal hemosiderosis, and moderate lymphocytic infiltration. 6 months after surgery, limb function was completely restored. Autovenous prosthetic repair of a section of the brachial artery with a pseudoaneurysm due to a gunshot wound is an effective surgical method of treatment and restoration of blood flow.

CD163+ Macrophages Induce Endothelial-to-Mesenchymal Transition in Atheroma.

Cell phenotype switching is increasingly being recognized in atherosclerosis. However, our understanding of the exact stimuli for such cellular transformations and their significance for human atherosclerosis is still evolving. Intraplaque hemorrhage is thought to be a major contributor to plaque progression in part by stimulating the influx of CD163+ macrophages. Here, we explored the hypothesis that CD163+ macrophages cause plaque progression through the induction of proapoptotic endothelial-to-mesenchymal transition (EndMT) within the fibrous cap. Human coronary artery sections from CVPath's autopsy registry were selected for pathological analysis. Athero-prone ApoE-/- and ApoE-/-/CD163-/- mice were used for in vivo studies. Human peripheral blood mononuclear cell-induced macrophages and human aortic endothelial cells were used for in vitro experiments. In 107 lesions with acute coronary plaque rupture, 55% had pathological evidence of intraplaque hemorrhage in nonculprit vessels/lesions. Thinner fibrous cap, greater CD163+ macrophage accumulation, and a larger number of CD31/FSP-1 (fibroblast specific protein-1) double-positive cells and TUNEL (terminal deoxynucleotidyl transferase-dUTP nick end labeling) positive cells in the fibrous cap were observed in nonculprit intraplaque hemorrhage lesions, as well as in culprit rupture sections versus nonculprit fibroatheroma sections. Human aortic endothelial cells cultured with supernatants from hemoglobin/haptoglobin-exposed macrophages showed that increased mesenchymal marker proteins (transgelin and FSP-1) while endothelial markers (VE-cadherin and CD31) were reduced, suggesting EndMT induction. Activation of NF-κB (nuclear factor kappa β) signaling by proinflammatory cytokines released from CD163+ macrophages directly regulated the expression of Snail, a critical transcription factor during EndMT induction. Western blot analysis for cleaved caspase-3 and microarray analysis of human aortic endothelial cells indicated that apoptosis was stimulated during CD163+ macrophage-induced EndMT. Additionally, CD163 deletion in athero-prone mice suggested that CD163 is required for EndMT and plaque progression. Using single-cell RNA sequencing from human carotid endarterectomy lesions, a population of EndMT was detected, which demonstrated significant upregulation of apoptosis-related genes. CD163+ macrophages provoke EndMT, which may promote plaque progression through fibrous cap thinning.

Translocator Protein 18 kDa Tracer 18F-FDPA PET/CTA Imaging for the Evaluation of Inflammation in Vulnerable Plaques.

Inflammation induced by activated macrophages within vulnerable atherosclerotic plaques (VAPs) constitutes a significant risk factor for plaque rupture. Translocator protein (TSPO) is highly expressed in activated macrophages. This study investigated the effectiveness of TSPO radiotracers, 18F-FDPA, in detecting VAPs and quantifying plaque inflammation in rabbits. 18 New Zealand rabbits were divided into 3 groups: sham group A, VAP model group B, and evolocumab treatment group C. 18F-FDPA PET/CTA imaging was performed at 12, 16, and 24 weeks in all groups. Optical coherence tomography (OCT) was performed on the abdominal aorta at 24 weeks. The VAP was defined through OCT images, and ex vivo aorta PET imaging was also performed at 24 weeks. The SUVmax and SUVmean of 18F-FDPA were measured on the target organ, and the target-to-background ratio (TBRmax) was calculated as SUVmax/SUVbloodpool. The arterial sections of the isolated abdominal aorta were analyzed by HE staining, CD68 and TSPO immunofluorescence staining, and TSPO Western blot. The results showed that at 24 weeks, the plaque TBRmax of 18F-FDPA in group B was significantly higher than in groups A and C. Immunofluorescence staining of CD68 and TSPO, as well as Western blot, confirmed the increased expression of macrophages and TSPO in the corresponding regions of group B. HE staining revealed an increased presence of the lipid core, multiple foam cells, and inflammatory cell infiltration in the area with high 18F-FDPA uptake. This indicates a correlation between 18F-FDPA uptake, inflammation severity, and VAPs. The TSPO-targeted tracer 18F-FDPA shows specific uptake in macrophage-rich regions of atherosclerotic plaques, making it a valuable tool for assessing inflammation in VAPs.

Evaluation of the correlation of wall elasticity between different sections of radial artery by velocity vector imaging.

This study aimed to evaluate the correlation between the elasticity of the anterior and posterior walls of the radial artery in different sections using velocity vector imaging. In this retrospective analysis, 30 healthy people who underwent physical examination in our hospital from January 2022 to January 2023 were analyzed offline by velocity vector imaging technology. The following parameters were assessed: peak systolic strain (Ss; %), peak diastolic strain (Sd; %), peak systolic strain rate (SRs; 1/s), and peak diastolic strain rate (SRd; 1/s). Elastic function was evaluated by analyzing the systolic and diastolic motion of the arterial walls. In the long-axis sections, there was a significant positive correlation between Ss, SRs, and SRd of both the anterior and posterior walls (r=0.531, r=0.803, and r=0.898, all p<0.01). Additionally, Sd showed a positive correlation (r=0.402, p<0.05). In the short-axis sections, there was a significant and positive correlation between SRs and SRd of both walls (r=0.762, r=0.667, both p<0.01). Furthermore, a positive correlation was found between SRd in the long-axis and short-axis sections of the anterior wall (r=0.382, p<0.05). Velocity vector imaging is a valuable tool for assessing the elasticity of the radial artery in different sections, and the longitudinal SRd in the long-axis section may serve as a highly sensitive and accurate parameter for assessing changes in wall elastic function during the occurrence of radial artery lesions.

A single institution experience of the Manta closure device in endovascular aortic repair.

Majority of EVAR procedures are performed with percutaneous arterial access, unless there is severe steno-occlusive disease in the common femoral arteries (CFA). We present our experience of using MANTA closure device with a retrospective evaluation of its safety and efficacy, in the elective setting, and in the emergent setting for ruptured aortic aneurysm. Between Feb 2021 and May 2023 a total of 75 EVAR procedures were closed with a Manta device. Data was collected prospectively and analysed retrospectively. In 75 patients, 128 CFAs were closed with a Manta closure device including 4 emergent ruptured aneurysms. 67 male and 8 female patients with a median age of 77 years had percutaneous EVAR using Manta as a closure device. 128 CFAs were closed with Manta closure device. 3% (4/128) had deployment failures, with three requiring surgical cut down and closure. In one patient, a second Manta device deployment achieved satisfactory haemostasis. Three deployments were complicated by pseudoaneurysms of the CFA, all requiring no further interventions/treatment. No death related to severe haemorrhage from device failure. The pre- and post-procedure CFA puncture site AP diameter was recorded in a total of 106 cases with appropriate follow-up. 66% of these (70/106) had no reduction in CFA diameter post Manta closure. 34% (36/106) had some reduction of vessel AP size CFA post EVAR. No adverse features or further treatment was required due to reduction of vessel diameter in these cases (ongoing yearly surveillance). Manta closure device is safe and easy to deploy with an overall success rate of 97%. There is a short learning curve. Ultrasound assessment and precise puncture at the healthy section of femoral artery are the key to achieve successful haemostasis with Manta closure device. Our findings suggest there is an association of non-clinically significant mild reduction in CFA vessel AP diameter post Manta closure device, which does not require further intervention.

Abstract 1156: Akkermansia (Strain BAA835) And The Microbial ADP-heptose Pathway Are Associated With Reduced Neointimal Hyperplasia After Arterial Injury

Introduction: Despite advances in surgical therapy for atherosclerosis, up to 50% of procedures such as balloon angioplasty, stenting, and bypass fail due to restenosis from neointimal hyperplasia, a cell proliferative process potentiated by inflammation. We hypothesized that neointimal hyperplasia is associated with a distinct gut microbiome profile and can be modulated by fecal transplantation. Methods: We performed fecal transplantation (FT) of C57BL6 mice using donors with differential microbiome profiles and susceptibility to neointimal hyperplasia (Sprague-Dawley [SD] and Lewis [LE] rats, high and low susceptibility, respectively). In separate experiments, germ-free mice underwent FT using C57BL6 donors with and without Akkermansia muciniphila BAA835 ( Amuc ) prior to arterial injury. Microbial communities were characterized using 16S rRNA gene amplicon and shotgun metagenome sequencing. Arterial and immune effects were assessed using frozen arterial sections, multi-parameter flow cytometry of mesenteric lymph nodes, or multiplex cytokine assays after ex vivo stimulation of whole blood with lipopolysaccharide. Results: Paradoxically, neointimal hyperplasia after injury was 67.7% greater in FT recipients of low- compared to high-susceptibility stools (P=0.01). In fecal communities of both FT recipient groups, relative abundance of A. muciniphila (r=-0.66, P&lt;0.001) and of the ADP-heptose biosynthesis pathway (r=-0.7, P&lt;0.001) were negatively associated with neointimal hyperplasia. A. muciniphila was differentially elevated (P&lt;0.001) in SD compared to LE FT recipients and was the main contributing taxa for the enrichment (P&lt;0.001) of the ADP-heptose biosynthesis pathway in the SD recipient group. In mice colonized with communities that differed only by the presence of Amuc , neointimal hyperplasia was 57.8% greater in the Amuc - group compared to Amuc+ (P=0.01). Amuc+ recipients had lower levels of IL-12, MIP-1beta, and MCP-1 in unstimulated blood and higher IP-10 and MCP-1 levels in stimulated blood. Conclusion: A. muciniphila and microbial ADP-heptose biosynthesis pathway are inversely associated with neointimal hyperplasia and are potential targets for novel microbe-based strategies to mitigate restenosis risk.

Utilizing radiomic features of arterial phase computed tomography for delineating parathyroid adenomas from surrounding anatomical structures

Aim: The study aimed to correlate radiomic data of four-dimensional computed tomography (4D-CT) with pathology-proven parathyroid adenomas to identify and quantitate select dimensional and textural features that predict parathyroid adenomas with a high degree of confidence, with the ultimate goal of improving the reliability of parathyroid adenoma detection so as to facilitate the subsequent unilateral minimally invasive parathyroidectomy (MIP). Methods: A total of 144 subjects with a history of neck 4D-CT, parathyroidectomy, and intraoperative pathology-proven parathyroid adenoma(s) were retrospectively reviewed. Following the exclusion of patients with a thyroidectomy, unsuccessful surgery, or indeterminate localization of the parathyroid adenoma on 4D-CT, a preliminary sample of 20 patients was obtained. Four anatomical structures (carotid artery, internal jugular vein, thyroid, and parathyroid adenoma) were segmented twice on 25-second arterial phase axial sections of a 4D-CT, and radiomic data of the shape, first-order, and second-order classes (106 variables) were extracted from the four structures for each patient. Results: Select radiomic variables among the carotid artery, jugular vein, and thyroid groups exhibited overall significant differences when compared to the parathyroid adenoma data (P &lt; 0.05). Further Tukey’s post hoc analysis revealed that, when the parathyroid adenoma group was treated as the reference, 11/16 shape class, 16/18 first-order class, and 46/69 second-order class variables significantly differ from the carotid artery, jugular vein, and/or thyroid group(s). In addition, we found that the thyroid has distinct textural features compared to the parathyroid group, with 1/18 first-order and 19/69 second-order variables differing significantly between the two (P &lt; 0.05). Notably, the texture variables such as dependence non-uniformity, long run emphasis, run percentage, run variance, and busyness exhibited the highest level of differences between the two groups (P &lt; 0.0001). Conclusion: The parathyroid adenoma group is associated with a unique set of radiomic variables in comparison to surrounding anatomy such as the carotid artery, internal jugular vein, and thyroid. Relevance for Patients: The distinct, quantifiable differences in dimensional and textural features serve as a set of signature markers distinguishing parathyroid adenomas from their surrounding structures in 4D-CT. These attributes obviate the need for invasively locating parathyroid adenomas preoperatively, thereby enhancing the utilization rate of MIP, which has a favorable implication in the overall clinical outcomes.

Increased uterine arterial tone, stiffness and remodeling with augmented matrix metalloproteinase-1 and -7 in uteroplacental ischemia-induced hypertensive pregnancy

Preeclampsia is a pregnancy-related disorder manifested as hypertensive pregnancy (HTN-Preg) and often fetal growth restriction (FGR), but the mechanisms involved are unclear. We have reported enhanced reactivity of systemic vessels in HTN-Preg rats, but the critical changes in the uterine circulation are less clear. We tested whether HTN-Preg involves localized aberrations in uterine arterial tone, stiffness and remodeling by matrix metalloproteinases (MMPs). Blood pressure (BP) and litter size were recorded in normal pregnant (Preg) rats and Preg rats with reduced uteroplacental perfusion pressure (RUPP). Isolated uterine arteries were placed in a pressure myograph for measuring intrinsic and extrinsic tone and arterial stiffness. Arteries were bathed in normal Krebs solution (2.5 mM Ca2+), Ca2+-free (2 mM EGTA) Krebs, treated with sodium nitroprusside (SNP), or endothelium denuded, then pressurized at 10 mmHg steps from 10 to 110 mmHg, and the % change in diameter was analyzed to measure total (active + passive), active Ca2+-dependent myogenic, passive, and endothelium-dependent tone, respectively. BP was higher and the litter size and pup weight were reduced in RUPP vs Preg rats. In normal Krebs, increasing intraluminal pressure caused smaller increments in diameter in arteries of RUPP vs Preg rats, suggesting greater total vascular tone. Arterial incubation in Ca2+-free Krebs, treatment with SNP or endothelium-removal abolished the differences in vascular tone, and subtraction of each of these components from total vascular tone revealed significant active Ca2+-dependent myogenic, passive, and endothelium-dependent tone, respectively, in RUPP vs Preg rats. The total and passive strain–stress curves were shifted leftward in arteries of RUPP vs Preg rats, indicating increased uterine arterial stiffness. Arterial sections showed decreased lumen/total and increased wall/total area, and immunohistochemistry revealed greater MMP-1 and MMP-7 staining particularly in the media, suggesting uterine arterial remodeling by MMPs in RUPP vs Preg rats. The increased uterine arterial active myogenic, passive, and endothelium-dependent tone, arterial stiffness and remodeling by MMPs would further reduce uterine blood flow and exacerbate uteroplacental ischemia, FGR and HTN-Preg.