Stenotic Artery Research Articles

Impact of gold and silver nanoparticles on the thermally radiating MHD slip blood flow within the stenotic artery using stability analysis and entropy optimisation

Impact of gold and silver nanoparticles on the thermally radiating MHD slip blood flow within the stenotic artery using stability analysis and entropy optimisation

M6A Modification of Profilin-1 in Vascular Smooth Muscle Cells Drives Phenotype Switching and Neointimal Hyperplasia via Activation of the p-ANXA2/STAT3 Pathway.

In-stent restenosis is characterized by a significant reduction in lumen diameter within the stented segment, primarily attributed to excessive proliferation of vascular smooth muscle cells (VSMCs) and neointimal hyperplasia. PFN1 (profilin-1), an actin-sequestering protein extensively studied in amyotrophic lateral sclerosis, remains less explored in neointimal hyperplasia. Utilizing single-cell RNA sequencing alongside data from in-stent restenosis patients and various experimental in-stent restenosis models (swine, rats, and mice), we investigated the role of PFN1 in promoting VSMC phenotype switching and neointimal hyperplasia. Single-cell RNA sequencing of stenotic rat carotid arteries revealed a critical role for PFN1 in neointimal hyperplasia, a finding corroborated in stented swine coronary arteries, in-stent restenosis patients, PFN1SMC-IKO (SMC-specific PFN1 knockout) mice, and PFN1 overexpressed mice. PFN1 deletion was shown to suppress VSMC phenotype switching and neointimal hyperplasia in PFN1SMC-IKO mice subjected to a wire-injured model. To elucidate the observed discordance in PFN1 mRNA and protein levels, we identified that METTL3 (N6-methyladenosine methyltransferase) and YTHDF3 (N6-methyladenosine-specific reader) enhance PFN1 translation efficiency in an N6-methyladenosine-dependent manner, confirmed through experiments involving METTL3 knockout and YTHDF3 knockout mice. Furthermore, PFN1 was mechanistically found to interact with the phosphorylation of ANXA2 (annexin A2) by recruiting Src, promoting the phosphorylation of STAT3, a typical transcription factor known to induce VSMC phenotype switching. This study unveils the significance of PFN1 N6-methyladenosine modification in VSMCs, demonstrating its role in promoting phenotype switching and neointimal hyperplasia through the activation of the p-ANXA2 (phospho-ANXA2)/STAT3 pathway.

Imaging of Ischemic Cholangiopathy Following Donation after Circulatory Death Liver Transplant.

Ischemic cholangiopathy (IC) is the leading cause of inferior long-term outcomes following donation after circulatory death (DCD) liver transplant. Biliary strictures related to IC are nonanastomotic strictures (NASs) by definition and involve the donor hepatic ducts proximal to the anastomosis, compared with postsurgical anastomotic strictures that form due to fibrotic healing. IC-related NASs can be microangiopathic with patent hepatic artery or macroangiopathic with occluded or stenotic hepatic artery. Recently, IC with NASs have been described to have four distinct patterns at imaging: diffuse necrosis, multifocal progressive, confluence dominant, and minor form, which correlate clinically with graft prognosis. Severe IC can lead to ductal wall breakdown with subsequent bile leaks that can cause significant patient morbidity, with imaging playing a vital role in diagnosis and guiding intervention. IC also predisposes the transplanted liver to biliary stasis and subsequent formation of stones, casts, and sludge. Some cases of posttransplant biliary stricturing are not IC but are a sequela of reflux cholangitis seen with choledochojejunal anastomosis. Other biliary findings in the posttransplant liver can be explained by sphincter of Oddi dysfunction that results from denervation. The authors describe and comprehensively categorize the various IC types and their imaging patterns at MRI and MR cholangiopancreatography, review the prognostic significance of these imaging patterns, and discuss imaging features of additional biliary complications associated with IC after DCD liver transplant. ©RSNA, 2024 Supplemental material is available for this article.

Computational hemodynamic simulation of non-Newtonian fluid-structure interaction in a curved stenotic artery

This paper focuses on deploying Computational Fluid Dynamics (CFD) and Fluid-Structure Interaction (FSI) to investigate key characteristics associated with Cardiovascular Diseases (CVDs), a leading cause of global mortality. CVDs encompass various heart and blood vessel disorders, including coronary artery disease, stroke and atherosclerosis, which significantly impact arteries. Risk factors such as high blood pressure and obesity contribute to atherosclerosis, which is characterized by narrowed arteries due to fatty deposits, impeding blood flow and increasing heart attack and stroke risks. To simulate blood flow behaviour and its effects on artery stenosis formation, ANSYS-based CFD and monolithic (one-way) Fluid-Structure Interaction (FSI) analyses are deployed in this work. Extensive visualization of blood flow patterns relevant to patient-specific conditions is included using the non-Newtonian (Carreau shear-thinning) bio-rheological model. These simulations start with creating a three-dimensional patient artery model, followed by applying CFD/FSI methodologies to solve the equations iteratively with realistic boundary conditions. Velocity, pressure, wall shear stress (WSS), Von mises stress and strain characteristics are all computed for multiple curvature cases and different stenotic depths. Factors such as blood viscosity, density and its non-Newtonian behaviour due to red blood cells are considered. FSI analysis extends CFD by including the interaction between blood flow and deformable (elastic) arterial walls, accounting for the arterial mechanical properties and the flow-induced pressure changes. Here we do not consider the two-way case where deformation in turn affects the flow, only the one-way (monolithic) case where the blood flow distorts the arterial wall. This approach allows for deeper insight into the interaction between rheological blood flow and elastic arterial walls which aids in highlighting high stress zones, recirculation and hemodynamic impedance of potential use in identifying rupture or plaque formation, contributing significantly to the management and prevention of CVDs.

Entropy generation minimization and activation energy in magneto-thermo-solutal stratified Ellis hybrid nanofluid flow through a stretching stenotic artery: Insights into cardiovascular disease

This article explores the impact of binary chemical reactions with activation energy on the flow of magnetized mono and hybrid nanofluids within a porous artery under the effects of viscous dissipation, nonlinear thermal radiation, and Joule heating. The main novelty of this study lies in considering a non-Newtonian Ellis fluid model of blood through a stretching stenotic artery consisting of gold (Au) and silver (Ag) nanoparticles. Additionally, velocity slip, convective temperature, and concentration boundary conditions are applied at the arterial surface. The proposed model compares the performance of Ag/Blood nanofluid and Au-Ag/Blood hybrid nanofluid models. The governing equations are solved using the bvp4c built-in solver in MATLAB, which employs advanced numerical techniques and algorithms tailored for BVPs, ensuring quicker convergence with minor errors and accurate solutions. Graphs are plotted for concentration, temperature, velocity, entropy minimization, skin friction coefficient, Nusselt number, and Sherwood number for various physical parameters. The results show that with increased nonlinear thermal radiation (0.1≤Nr≤2.0), thermal Biot number (0.1≤Bi1≤0.3), and Eckert number (0.01≤Ec≤0.2), the thermal distribution profile exhibits a rising trend. In contrast, with increasing fluctuations in the chemical reaction rate parameter (0.1≤Rc≤0.3) and Schmidt number (1.0≤Sc≤3.0), the concentration distribution profile exhibits a decreasing trend. In terms of mass and heat transfer efficiency, the Au-Ag/Blood hybrid nanofluid flow outperforms the Ag/Blood nanofluid model. More entropy is observed for Au-Ag/Blood compared to Ag/Blood in the stenotic artery. Heat energy may be created by targeting the injured area and avoiding harm to nearby tissues. Localized heating can widen arteries and increase blood flow to the affected locations, potentially aiding cardiovascular health management and personalized therapy. This study has various implications for the design of drug delivery systems, biophysical models, innovative materials, and our knowledge of fluid dynamics and heat transfer. However, nanofluid/hybrid nanofluid stability is challenging for current researchers since this modeled flow can be considered over a shrinking artery or in the trihybrid model in future studies.

Complement factor B, not the membrane attack complex component C9, promotes neointima formation after arterial wire injury

Background and aimsVascular restenosis due to neointima hyperplasia limits the long-term patency of stented arteries, resulting in angioplasty failure. The complement system has been implicated in restenosis. This study aimed to investigate the role of complement factor B (fB), an essential component of the alternative pathway of complement activation, in neointima formation. MethodsAngioplasty wire injury was conducted using 12-week-old mice deficient in fB or C9 (the main component of the membrane attacking complex, C5b-9) and littermate controls and neointima formation were assessed. Vascular smooth muscle cell (SMC) and endothelial cell (EC) proliferation and migration were examined in vitro. ResultsfB was mainly detected in SMCs of stenotic arteries from humans and mice. Deletion of fB substantially reduced the neointima area and intima-to-media area ratio without affecting the media area at 28 days after injury. At 7 days after injury, fB deficiency decreased SMC proliferation, unaltering neointimal macrophage infiltration and EC reendothelialization. Vascular SMC-expressed fB, not the circulation-sourced fB, played an essential role in SMC proliferation and migration in vitro. fB deficient mice exhibited lower levels of the soluble form of C5b-9, however, deletion of C9 did not alter neointima formation after wire injury, consistent with the null impact of C9 deficiency on SMC proliferation in vitro. ConclusionfB promotes neointima formation following wire-induced artery injury independent of forming the membrane-attacking complex. This is attributable to fB-dependent SMC proliferation and migration without affecting EC function. Targeting fB might protect against restenosis after percutaneous coronary intervention.

Unraveling the complex interplay between abnormal hemorheology and shape asymmetry in flow through stenotic arteries

Background and Objective:Stenosis or narrowing of arteries due to the buildup of plaque is a common occurrence in atherosclerosis and coronary artery disease (CAD), limiting blood flow to the heart and posing substantial cardiovascular risk. While the role of geometric irregularities in arterial stenosis is well-documented, the complex interplay between the abnormal hemorheology and asymmetric shape in flow characteristics remains unexplored. Methods:This study investigates the influence of varying hematocrit (Hct) levels, often caused by conditions such as diabetes and anemia, on flow patterns in an idealized eccentric stenotic artery using computational fluid dynamics simulations. We consider three physiological levels of Hct, 25%, 45%, and 65%, representing anemia, healthy, and diabetic conditions, respectively. The numerical simulations are performed for different combinations of shape eccentricity and blood rheological parameters, and hemodynamic indicators such as wall shear stress (WSS), oscillatory shear index (OSI), are relative residence time (RRT) are calculated to assess the arterial health. Results:Our results reveal the significant influence of Hct level on stenosis progression. CAD patients with anemia are exposed to lower WSS and higher OSI, which may increase the propensity for plaque progression and rupture. However, for CAD patients with high Hct level—as is often the case in diabetes—the WSS at the minimal lumen area increases rapidly, which may also lead to plaque rupture and cause adverse events such as heart attacks. These disturbances promote endothelial dysfunction, inflammation, and thrombus formation, thereby intensifying cardiovascular risk. Conclusions:Our findings underscore the significance of incorporating hemorheological parameters, such as Hct, into computational models for accurate assessment of flow dynamics. We envision that insights gained from this study will inform the development of tailored treatment strategies and interventions in CAD patients with common comorbidities such as diabetes and anemia, thus mitigating the adverse effects of abnormal hemorheology and reducing the ever-growing burden of cardiovascular diseases.

Soluble Glycoprotein VI Levels Assessed Locally within the Extra- and Intracerebral Circulation in Hyper-Acute Thromboembolic Stroke: A Pilot Study.

Background: Severe acute ischemic stroke (AIS) is mainly caused by thromboembolism originating from symptomatic carotid artery (ICA) stenosis or in the heart due to atrial fibrillation. Glycoprotein VI (GPVI), a principal platelet receptor, facilitates platelet adherence and thrombus formation at sites of vascular injury such as symptomatic ICA stenosis. The shedding of GPVI from the platelet surface releases soluble GPVI (sGPVI) into the circulation. Here, we aimed to determine whether sGPVI can serve as a local biomarker to differentiate between local atherosclerotic and systemic cardiac thromboembolism in AIS. Methods: We conducted a cohort study involving 105 patients undergoing emergency endovascular thrombectomy (EVT) for anterior circulation stroke. First, sGPVI concentrations were measured in systemic arterial plasma samples collected at the ipsilateral ICA level, including groups with significantly (≥50%) stenotic and non-stenotic arteries. A second sample, taken from the intracerebral pial circulation, was used to assess GPVI shedding locally within the ischemic brain. Results: Our analysis revealed no significant increase in systemic sGPVI levels in patients with symptomatic ≥ 50% ICA stenosis (3.2 [95% CI 1.5-5.0] ng/mL; n = 33) compared with stroke patients without significant ICA stenosis (3.2 [95% CI 2.3-4.2] ng/mL; n = 72). Additionally, pial blood samples, reflecting intravascular molecular conditions during collateral flow, showed similar sGPVI levels when compared to the systemic ICA samples in both groups. Conclusions: Our findings indicate that GPVI is not locally cleaved and shed into the bloodstream in significant amounts during hyper-acute ischemic stroke, neither at the level of symptomatic ICA nor intracranially during collateral blood supply. Therefore, sGPVI does not appear to be suitable as a local stroke biomarker despite strong evidence of a major role for GPVI-signaling in stroke pathophysiology.

Features and Limitations of Robotically Assisted Percutaneous Coronary Intervention (R-PCI): A Systematic Review of R-PCI.

Background: Ischaemic heart disease is one of the major drivers of cardiovascular death in Europe. Since the first percutaneous coronary intervention (PCI) in 1977, developments and innovations in cardiology have made PCI the treatment of choice for stenotic coronary artery disease. To address the occupational hazards related to chronic exposure to radiation and wear and tear from heavy lead-based radioprotective aprons, the concept of robotically assisted PCI (R-PCI) was introduced in 2005. Aim: To explore the features and limitations of R-PCI, we first discuss the concept and evolution of R-PCI platforms and then systematically review the available clinical data. Methods: A systematic review has been performed across the Pubmed, Embase and Cochrane databases in order to assess the efficacy and safety of R-PCI. Secondary endpoints, such as operator and patient exposure to radiation, contrast volume used and procedural time, were assessed when available. Results: In selected patients, R-PCI provides high technical and clinical success rates, ranging from 81 to 98.8% and from 93.3 to 100%, respectively. In-hospital and 1-year MACE rates ranged from 0 to 10.4% and 4.8 to 10.5%, respectively. R-PCI is able to significantly reduce the operator's exposure to radiation. Further research analysing the patient's and cath lab staff's exposure to radiation is needed. Therapy escalation with R-PCI seems to be limited to complex lesions. R-PCI procedures add approximately 10 min to the procedural time. Conclusions: The efficacy and safety of R-PCI have been proven, and R-PCI is able to significantly reduce occupational hazards for the first operator. The lack of adoption in the community of interventional cardiologists may be explained by the fact that current generations of R-PCI platforms are limited by their incompatibility with advanced interventional devices and techniques needed for escalation in complex interventions.

Lipoprotein-associated phospholipase A2 activity levels is associated with artery to artery embolism in symptomatic intracranial atherosclerotic disease

BackgroundLipoprotein-associated phospholipase A2 activity (Lp-PLA2-A) is a pivotal enzyme involved in the inflammatory process and atherosclerotic plaque vulnerability. This study aimed to investigate the potential of Lp-PLA2-A as a biomarker for reflecting artery-to-artery embolism (AAE), a critical mechanism with high risk of stroke recurrence in symptomatic intracranial atherosclerotic disease (sICAD). MethodsThe current analysis included a cohort of 1,908 patients with sICAD and baseline levels of Lp-PLA2-A from the Third China National Stroke Registry (CNSR-III). The baseline Lp-PLA2-A levels were quantified centrally using an automatic enzyme assay system. Diagnosis of sICAD was made by experienced stroke neurologists based on the presence of a cerebral infarction within the territory of a stenotic (>50 %) or occluded artery, or when clinical symptoms were consistent with the diagnosis. Infarct lesions affecting the cortex serve as imaging biomarkers for stroke mechanism involving AAE.The relationship between baseline Lp-PLA2-A quartile levels and the presence of cortical infarction was analyzed using multivariate logistic regression. ResultsCompared to patients in the first Lp-PLA2-A quartile, those in the second, third and fourth quartiles demonstrated a significantly higher proportion of AAE. The proportion of patients with cortical infarction increased with rising Lp-PLA2-A quartiles, observed at 39.3 %, 47.1 %, 47.4 %, and 50.7 % for the first, second, third and fourth quartiles respectively (P for trend=0.004). Compared with the first quartile, the odds ratios (ORs) were 1.38 (95 % CI = 1.06-1.79) for the second, 1.33 (95 % CI = 1.02-1.72) for the third quartile and 1.48 (95 % CI = 1.14-1.92) for the fourth quartile. The association between higher Lp-PLA2-A and increased proportion of cortical infarction was also present in the subgroups defined by age <65 years, male, and high-sensitivity C-reactive protein ≥2 mg/L. In sensitivity analyses, the positive correlation between Lp-PLA2-A levels and proportion of cortical infarction remained consistent. ConclusionsThis research highlights the significance of Lp-PLA2-A as a biomarker for reflecting stroke mechanism in sICAD. Additional studies are warranted to explore the potential of targeting Lp-PLA2-associated inflammatory pathways as a pivotal approach in arresting the advancement of intracranial atherosclerotic stenosis and reducing the incidence of embolic strokes.

Advancing Blood Flow in Stenotic Arteries through Magnetohydrodynamic Peristaltic Motion of Hybrid Nanoparticles

This research aims to investigate the efficacy of hybrid nanoparticles in improving magnetohydrodynamic (MHD) peristaltic blood flow in stenotic arteries. Hybrid nanoparticles combining MHD processes and peristaltic motion show promise for increasing blood flow through constricted arteries. To evaluate the impact of nanoparticles on blood flow parameters, researchers use theoretical modelling and analytical solutions. Incorporating copper and aluminium oxide nanoparticles (Cu-Al2O3) into blood, leading to the formation of an ionic solution, is a crucial step in creating a homogeneous hybrid blood suspension. The mathematical model uses approximations of the stenosis and non-dimensional parameters for a mild stenosis scenario to simplify the underlying coupled nonlinear partial differential equations. Analytical solutions for various blood flow parameters such as velocity, temperature, stream function, wall shear stress, Nusselt number, and flow resistance impedance are obtained using the perturbation technique. This study visually analyzes how different physiological variables affect arterial blood flow characteristics. The heat conductivity of blood is an essential aspect of preserving one's sustenance, which is largely determined by the concentration of hybrid nanoparticles. A streamlined pattern depicts the direction of blood flow within an artery. This research demonstrates that the adverse effects of vascular stenosis can be mitigated by using hybrid nanoparticles. In order to aid narrowed arteries, these nanoparticles lessen wall shear stress, boost axial flow speed, and enhance the velocity profile.

Resting segmental speckle tracking strain and strain rate in stable coronary artery disease and revascularized myocardial infarction

Patients with acute coronary artery disease (CAD) exhibit reduced global and regional strain and strain rate (S/SR). However, knowledge about segmental S/SR in stable CAD patients is still limited. This study aimed to investigate whether resting segmental S/SR measurements differ in patients with chronic chest pain who have normal coronary arteries or stenotic coronary arteries, and to compare these measurements to those in patients with revascularized myocardial infarction (MI). We prospectively enrolled 510 patients with chronic chest pain referred for coronary computed tomography angiography (CCTA) and 102 patients revascularized after MI. All participants underwent transthoracic echocardiography featuring S/SR analysis. In addition to the patients with MI, patients with suspected CAD based on CCTA findings subsequently underwent invasive coronary angiography (CAG). We assessed global longitudinal strain (GLS) and averaged segmental peak longitudinal strain during systole (PLS), peak systolic strain rate (SRs), peak early diastolic strain rate (SRe), and post systolic shortening (PSS). We also determined functionally reduced segment percentages using differing S/SR cut-off values. There were significant disparities in all average segmental S/SR metrics between the No-CAD and MI groups. SRe was the only S/SR metric that differed significantly between the No-CAD and PCI groups. Differences in SRe, PLS and GLS measurements were observed between the No-CAD and CABG groups. The proportion of diminished segmental S/SR mirrored these findings. For the percentage of pathological segments with varying cut-off values, segmental SRe below 1.5 s− 1 displayed the most marked difference among the four groups (p < 0.001). Revascularized MI patients or those referred to CABG present with diminished segmental S/SR values. However, among patients with chronic chest pain, only segmental SRe discerns subtle disparities between the No-CAD and the PCI group. The diagnostic accuracy of SRe warrants further exploration in subsequent studies.

Novel treatments for the radiative-magnetive Ellis hybrid nanofluids flow inside stenotic shrinking artery with imposed convective slip boundary conditions and entropy generation: An application in cardiovascular disease

This research delves into the theoretical and computational analysis of blood flow dynamics within a constricted, porous artery using a novel hybrid nanofluid model known as the Ellis model, which incorporates gold and silver nanoparticles. The investigation encompasses a spectrum of physical phenomena, including magnetic effects, Darcy-Forchheimer porous medium flow, viscous dissipation, and non-linear thermal radiation. Additionally, a convective slip boundary condition is applied at the arterial surface. By transforming the governing nonlinear partial differential equations into nonlinear ordinary differential equations, the study facilitates a comprehensive analysis. Subsequently, employing the bvp4c algorithm in MATLAB enables the numerical solution of these equations, yielding dual solutions for the system. Graphical representations are then utilized to elucidate various profiles, including velocity, temperature, skin friction coefficient, Nusselt number, and entropy. The findings highlight intriguing trends, such as the contrasting behaviors of skin friction and Nusselt number between the Au/Blood nanofluid and the Au − Ag/Blood hybrid nanofluid. Dual solutions can not be found beyond the critical values of suction (Sc) and curvature (γc) parameters. The critical values Sc are 2.3554 and 2.3170; γc are 0.2248 and 0.2654 for Au/Blood and Au − Ag/Blood, respectively. Moreover, insights are gained into the influence of magnetic field, Darcy-Forchheimer parameters on velocity reduction and the effect of the Ellis fluid, velocity slip parameters on temperature reduction profile. The heat transference rate increases in the situation of augmentation in shrinking parameyer and thermal radiation effect, which helps remove the toxic plaque from the blood flowing at the surface of the artery. Notably, the study underscores the significance of nanoparticle presence, porous and magnetic field parameters in enhancing entropy near the artery, with implications for cancer treatment and stroke prevention strategies.

Analyzing heat transfer and entropy generation in catheterized, stenosed arteries

A frequent cardiovascular condition that reduces blood flow is arterial stenosis. Tangent stress pressure, produced by a stenotic blood artery, diminishes the arterial side and results in an aneurysm. We explored the dynamics of entropy generation in blood stream via arteries observing mild overlapping stenosis, using a Prandtl fluid and focusing on the eccentric placement of catheters to enhance patient comfort. The governing equations assume conditions of mild stenosis and low Reynolds number, and applied the homotopy perturbation method. Several critical physical aspects are characterized, including velocity, temperature, impedance, entropy generation, wall shear stress, the Bejan number, and flow streamlines. The results show that a rise in the catheter radius tends to elevate impedance levels, whereas an increase in eccentricity, amplitude ratio, and inner cylinder speed leads to a decrease. These behaviors may serve to optimize catheter placement to minimize patient discomfort during medical interventions.

Celiac artery stenosis and its impact on postoperative outcomes following pancreaticoduodenectomy: An institutional analysis.

The detection of a stenotic celiac artery (CA) typically mandates intraoperative revascularization during pancreaticoduodenectomy (PD) to preserve liver perfusion. The impact of CA stenosis on postoperative outcomes is unclear. This study evaluates whether CA stenosis (CAS) is associated with increased postoperative complications. We conducted a retrospective analysis of PD patients from February 2014 to February 2022. Preoperative imaging assessed the CA lumen, categorizing it as patent, <50%, or ≥50% stenosis. Patients with narrowed SMA were excluded. Complications were categorized using the Clavien-Dindo system, and statistical analyses identified outcome differences. We included 427 patients in the study. Of these, 52 had CAS, and 311 had no-vessel stenosis (NVS). The median age of the CAS and NVS groups was 68 and 65 years, respectively. Postoperatively, 17.6% of patients with CAS exhibited delayed gastric emptying (DGE) versus 25.3% in the NVS group. Postoperative pancreatic fistula (POPF) was found in 13.5% of patients with CAS, compared with 23.7% without stenosis. The median length of hospital stay was shorter for patients with CAS (9 days) than for those with CAS (12 days). Severity-based classifications indicated higher complications in the no stenosis group and a 33.0% readmission rate within 30 days compared with 21.2% in CAS patients. However, none of these differences were statistically significant. Critical stenosis of the CA does not significantly affect postoperative outcomes following PD, suggesting preoperative correction of the narrowed CA may not be necessary. Further research is needed to confirm these findings.

The association between cardiac T2*BOLD and quantitative flow ratio (QFR) in the diagnosis of stenotic coronary arteries in patients with multi-vessel coronary artery disease.

T2*BOLD is based on myocardial deoxyhemoglobin content to reflect the state of myocardial oxygenation. Quantitative flow ratio is a tool for assessing coronary blood flow based on invasive coronary angiography. This study aimed to evaluate the correlation between T2*BOLD and QFR in the diagnosis of stenotic coronary arteries in patients with multi-vessel coronary artery disease. Fifty patients with MVCAD with at least 1 significant coronary artery stenosis (diameter stenosis > 50%) and 21 healthy control subjects underwent coronary angiography combined with QFR measurements and cardiovascular magnetic resonance (CMR). QFR ≤ 0.80 was considered to indicate the presence of hemodynamic obstruction. Totally 60 (54%) obstructive vessels had hemodynamic change. Between stenotic coronary arteries (QFR ≤ 0.8) and normal vessels, T2*BOLD showed AUCs of 0.97, 0.69, and 0.91 for left anterior descending (LAD), left circumflex (LCX) and right coronary (RCA) arteries and PI displayed AUCs of 0.89, 0.77 and 0.90 (all p > 0.05, except for LAD). The AUCs of T2*BOLD between stenotic coronary arteries (QFR > 0.8) and normal vessels were 0.86, 0.72, and 0.85 for LAD, LCX and RCA; while, PI showed AUCs of 0.93, 0.86, and 0.88, respectively (p > 0.05). Moreover, T2*BOLD displayed AUCs of 0.96, 0.74, and 0.91 for coronary arteries as before between coronary arteries with stenosis (QFR ≤ 0.8 and > 0.8), but the mean PI of LAD, LCX and RCA showed no significant differences between them. T2* BOLD and QFR have good correlation in diagnosing stenotic coronary arteries with hemodynamic changes in patients with stable multi-vessel CAD. T2* BOLD is superior to semi-quantitative perfusion imaging in analyzing myocardial ischemia without stress.

Fabrication, characterization and numerical validation of a novel thin-wall hydrogel vessel model for cardiovascular research based on a patient-specific stenotic carotid artery bifurcation

In vitro vascular models, primarily made of silicone, have been utilized for decades for studying hemodynamics and supporting the development of implants for catheter-based treatments of diseases such as stenoses and aneurysms. Hydrogels have emerged as prominent materials in tissue-engineering applications, offering distinct advantages over silicone models for fabricating vascular models owing to their viscoelasticity, low friction, and tunable mechanical properties. Our study evaluated the feasibility of fabricating thin-wall, anatomical vessel models made of polyvinyl alcohol hydrogel (PVA-H) based on a patient-specific carotid artery bifurcation using a combination of 3D printing and molding technologies. The model’s geometry, elastic modulus, volumetric compliance, and diameter distensibility were characterized experimentally and numerically simulated. Moreover, a comparison with silicone models with the same anatomy was performed. A PVA-H vessel model was integrated into a mock circulatory loop for a preliminary ultrasound-based assessment of fluid dynamics. The vascular model's geometry was successfully replicated, and the elastic moduli amounted to 0.31 ± 0.007 MPa and 0.29 ± 0.007 MPa for PVA-H and silicone, respectively. Both materials exhibited nearly identical volumetric compliance (0.346 and 0.342% mmHg−1), which was higher compared to numerical simulation (0.248 and 0.290% mmHg−1). The diameter distensibility ranged from 0.09 to 0.20% mmHg−1 in the experiments and between 0.10 and 0.18% mmHg−1 in the numerical model at different positions along the vessel model, highlighting the influence of vessel geometry on local deformation. In conclusion, our study presents a method and provides insights into the manufacturing and mechanical characterization of hydrogel-based thin-wall vessel models, potentially allowing for a combination of fluid dynamics and tissue engineering studies in future cardio- and neurovascular research.

Indications for cerebral revascularization for moyamoya syndrome in pediatric sickle cell disease determined by Delphi methodology.

Cerebral revascularization surgery (CRS) has been used to prevent stroke in children with sickle cell disease (SCD) and cerebral vasculopathy (e.g., moyamoya syndrome). While results suggest that it may be an effective treatment, surgical indications have not been well defined. This study sought to determine indications for offering revascularization surgery in centers with established sickle cell programs in the US. Three sequential surveys utilizing the Delphi methodology were administered to neurosurgeons participating in the Stroke in Sickle Cell Revascularization Surgery study. Respondents were presented with clinical scenarios of patients with SCD and varying degrees of ischemic presentation and vasculopathy, and the group's agreement to offer surgical revascularization was measured. Consensus was defined as ≥ 75% similar responses. The response rate to all 3 surveys was 100%. Seventeen neurosurgeons from 16 different centers participated. The presence of moyamoya collaterals (MMCs) and arterial stenosis matching an ischemic distribution yielded the strongest recommendations to offer surgery. There was consensus to offer revascularization in the presence of MMCs and at least 50% arterial stenosis matching an ischemic distribution. In contrast, there was no consensus to offer revascularization with 50%-70% stenosis not matching an ischemic presentation in the absence of MMCs. The presence of the ivy sign in the distribution of the stenotic artery also contributed to the consensus to offer surgery in certain scenarios. There were several clinical scenarios that attained consensus to offer surgery; the strongest was moderate to severe arterial stenosis that matched the distribution of ischemic presentation in the presence of MMCs. Radiological findings of decreased cerebral flow or perfusion also facilitated attaining consensus to offer surgery. The findings of this study reflect expert opinion about questions that deserve prospective clinical research. Determination of indications for CRS can guide clinical practice and aid the design of prospective studies.

Numerical investigation of Casson fluid flow performance of blood containing gold and Fe3O4 nanofluid injected into a stenotic artery

The study of the movement of blood across a stenotic artery is an important one in the discipline of mathematical fluid mechanics because of the importance it has in the field of biomedical research. The current study’s primary objective is to learn how nanoparticles influence blood flow through a narrowed artery. Within an examination of the theoretical flow situation, we investigate the importance of Casson nanofluid flow across a heart artery. Similarity transformations aid in the conversion of the partial differential equations into ordinary differential equations. After that, the non-dimensional equations are solved by using the MATLAB software in the Bvp5c technique. Enhancing the magnetic characteristics of the blood stream tissues was explored by boosting the magnetic field parameter, leading to a decrease in blood circulation as expected. At higher values of the Casson fluid parameter, the velocity profile decreased. Increasing the concentration of gold particles in the narrowed artery makes it more efficient at transferring heat. The use of iron nanoparticles in medicine delivery is supported by an argument. The method that is currently being used may be of assistance in dispersing pharmaceuticals across the blood stream. We employ a visual representation to facilitate the presentation of this drug delivery mechanism’s theoretical outcomes.

Studying the effects of electro-osmotic and several parameters on blood flow in stenotic arteries using CAGHPM

In this investigation, a new approach is proposed to study blood flow through a stenotic artery under the impact of electro-osmosis and several other main parameters. The new approach depends on the Chebyshev series, the Akbari-Ganji method, and the new homotopy perturbation method named the Chebyshev Akbari-Ganji homotopy perturbation method (CAGHPM). The validity of the proposed method was ensured by the good agreement of its results with the results obtained by other methods mentioned in previous studies. The influences of the electro-osmotic parameter and the Helmholtz-Smoluchowski velocity, as well as the inclination angle, magnetic field, porosity, and chemical reaction, are discussed in terms of the velocity, temperature, wall shear stress, and concentration of blood flow. The results obtained by using the CAGHPM are more accurate than those obtained by other methods used to solve the current problem. Furthermore, error tables, figures, and convergence analysis theoretically and computationally show the efficiency and effectiveness of the proposed new method.