Artery Blood Flow Research Articles

Research progress of neurovascular units involved in ischemic stroke

AbstractIschemic stroke is the most prevalent cerebrovascular disorder in the clinical setting. It results in associated neurological abnormalities due to a variety of factors, including disruption of cerebral arterial blood flow, hypoxia, and ischemic necrosis of local brain tissues. The neurovascular unit (NVU) is a dynamic structural complex that consists of neurons, glial cells, pericytes, vascular endothelial cells, and the extracellular matrix. Many cells work together to preserve the integrity of the central nervous system (CNS) under physiological conditions. However, following ischemic stroke, NVU homeostasis is disrupted along with the development of tissue ischemia and hypoxia, as well as impaired interactions between various components of the NVU. Collectively, the changes result in increased blood–brain barrier permeability, neuronal dysfunction, and functional destruction of nerve conduction bundles, ultimately leading to the clinical manifestation of neurological deficits including motor, cognitive, and speech impairments that hinder the rehabilitation process. In recent years, with continuously expanding research on ischemic cerebrovascular disease, the role of interconnections between different cells in the NVU in ischemic stroke has received increasing attention. To describe new concepts for the prevention and treatment of ischemic cerebrovascular illnesses, this article reviews the interplay between NVU in the pathogenesis of ischemic stroke.

Perivascular Adipose Tissue and Uterine Artery Adaptations to Pregnancy.

Pregnancy is characterized by longitudinal maternal, physiological adaptations to support the development of a fetus. One of the cardinal maternal adaptations during a healthy pregnancy is a progressive increase in uterine artery blood flow. This facilitates sufficient blood supply for the development of the placenta and the growing fetus. Regional hemodynamic changes in the uterine circulation, such as a vast reduction in uterine artery resistance, are mainly facilitated by changes in uterine artery reactivity and myogenic tone along with remodeling of the uterine arteries. These regional changes in vascular reactivity have been attributed to pregnancy-induced adaptations of cell-to-cell communication mechanisms, with an emphasis on the interaction between endothelial and vascular smooth muscle cells. Perivascular adipose tissue (PVAT) is considered the fourth layer of the vascular wall and contributes to the regulation of vascular reactivity in most vascular beds and most species. This review focuses on mechanisms of uterine artery reactivity and the role of PVAT in pregnancy-induced maternal vascular adaptations, with an emphasis on the uterine circulation.

Wave Separation Analysis to Assess Cardiovascular Alterations Induced by Sepsis.

Sepsis induces a severe decompensation of arterial and cardiac functional properties, leading to important modifications of arterial blood pressure (ABP) waveform, not resolved by recommended therapy, as shown by previous works. The aim of this study is to quantify the changes in ABP waveform morphology and wave reflections during a long-term swine experiment of polymicrobial sepsis and resuscitation, to deepen the understanding of the cardiovascular response to standard resuscitation therapy. We analyzed 14 pigs: polymicrobial sepsis was induced in 9 pigs followed by standard resuscitation and 5 pigs were treated as sham controls. Septic animals were studied at baseline (T1), after sepsis development (T2), and after 24 h (T3) and 48 h (T4) of therapy administration, and sham controls at the same time points. ABP and arterial blood flow were measured in the left and right carotid artery, respectively. Pulse wave analysis and wave separation techniques were used to estimate arterial input impedance, carotid characteristic impedance, forward and backward waves, indices of wave reflections such as reflection magnitude and reflection index, and augmentation index. Sepsis led to an acute alteration of ABP waveform passing from type A to type B or C; consistently, the reflection phenomena were significantly reduced. The resuscitation was successful in reaching targeted hemodynamic stability, but it failed in restoring a physiological blood propagation and reflection. Septic pigs persistently showed altered reflected waves even after 48 hours of successful therapy according to guidelines, suggesting a persistent hidden cardiovascular disorder. The proposed indices may be useful to unravel the complex cardiovascular response to therapy administration in septic patients and could potentially be used for risk stratification of patient deterioration. Whether alterations of blood propagation and reflection contribute to persisting organ dysfunction after hemodynamic stabilization should be further investigated.

A phase II study of plerixafor combined with whole brain radiation therapy (WBRT) for patients with newly diagnosed glioblastoma.

2075 Background: Plerixafor inhibits the binding of stromal cell-derived factor 1 (SDF-1a / CXCL12) to its receptor on CD11b+ monocytes, inhibiting vasculogenesis and tumor recurrence in preclinical models. An early phase trial demonstrated that Plerixafor administration decreased cerebral blood volume (CBV) within the irradiated field of glioblastoma patients, and that the majority of recurrences occurred outside of the irradiated field (Thomas R. et al, Clin Cancer Res). This follow up study investigates the efficacy of Plerixafor in combination with WBRT, with the hypothesis that widening the radiation therapy (RT) field with WBRT may reduce out-of-field tumor recurrence and improve survival. Methods: This was a Phase II, open-label, non-randomized, single-arm trial.Adults between 18-75 years old with newly diagnosed high grade glioma as defined by WHO 2016 criteria and KPS ≥ 60 were eligible for enrollment. Patients underwent maximal safe resection followed by 6 weeks of concurrent radiation therapy and temozolomide (TMZ). Of note, modifications to the conventional treatment paradigm included completing 30 Gy of standard intensity-modulated RT followed by 30 Gy of WBRT, as well as completing a 4-week continuous infusion of Plerixafor dosed at 400 µg/kg/day. Patients then started adjuvant TMZ after completing Plerixafor. Primary endpoint was 6-month progression free survival (PFS6) after chemoradiation. Secondary endpoints included median overall survival (mOS), adverse events (AEs), MRI-based patterns of recurrence, and neurocognitive outcomes measured by the Trail Making Test, Controlled Oral Word Association Test, and the Hopkins Verbal Learning Test. Additionally, maximum arterial spin labeling-cerebral blood flow (ASL-CBF) values of primary lesions were compared over various time points during the study. Results: 14 of 17 enrolled patients completed the Plerixafor infusion, and all 17 patients completed WBRT. Median age was 57 years. 15 patients (88.2%) were IDH wildtype and 13 patients (76.5%) were pMGMT unmethylated. 13 patients (76.5%) underwent gross total resection, 2 (11.8%) underwent subtotal resection, and 2 (11.8%) underwent biopsy only. The PFS6 was 91.7%. The mOS was 15.11 months. 3 patients discontinued Plerixafor early due to rash (n=1), rising creatinine (n=1), or worsening confusion and agitation (n=1). Common Gr2 treatment-related AEs included alopecia (n=4), nausea (n=4), and vomiting (n=2). 1 patient had Gr3 alopecia. There were no Grade 4/5 AEs. 80% of patients scored worse on their neurocognitive assessments at 6 months compared to screening. ASL-CBF values of primary lesions appeared relatively stable throughout the study. Conclusions: The combination of Plerixafor and WBRT did not improve mOS compared to the original study using focused RT only. There was an overall decline in neurocognitive performance over the course of the study. Clinical trial information: NCT03746080 .

Quantitative Analysis of Hemodynamic Changes in Branch Arteries Covered by Flow Diverters.

Understanding post-treatment hemodynamic alterations and their association with the patency of covered branch arteries is limited. This study aims to identify hemodynamic changes after flow diverter stenting and investigate their correlation with the patency status of covered branch arteries. All patients treated with pipeline embolization device for anterior cerebral artery aneurysms at our center between 2016 and 2020 were screened for inclusion. Quantitative digital subtraction angiography was used to analyze changes in hemodynamic parameters pre- and post-stenting. The patency status of covered branch arteries after stenting was categorized as either patent or flow impairment (defined as artery stenosis or occlusion). A total of 71 patients, encompassing 89 covered branch arteries, were enrolled. Flow impairment was observed in 11.2% (10/89) of the branches. The mean transit time and full width at half maximum (FWHM) in covered branches were significantly prolonged post-stenting (P = .004 and .023, respectively). Flow-impaired branch arteries exhibited hemodynamic shifts contrary to those in patent branch arteries. Specifically, flow-impaired branches showed marked reductions in time to peak, FWHM, and mean transit time (decreases of 32.8%, 32.6%, and 29%, respectively; P = .006, .002, and .002, respectively). Further multivariate analysis revealed that reductions in FWHM in the branches (odds ratio = 0.97, 95% CI: 0.95-0.99, P = .007) and smoking (odds ratio = 14.5, 95% CI: 1.39-151.76, P = .026) were independent predictors of flow impairment of covered branches. Pipeline embolization device stenting can cause a reduction in blood flow in branch arteries. Compared with patent branches, flow-impaired branches exhibit an increase in blood flow velocity after stenting. Smoking and ΔFWHM in the covered branches indicate flow impairment.

Initial Experience of the Covered Endovascular Reconstruction of Iliac Bifurcation Technique.

The distal landing zone in iliac arteries represents an important issue during endovascular repair of abdominal aortic aneurysms (EVAR). The aim of this study is to present a case series for landing in the external iliac artery (EIA) during EVAR while preserving blood flow in the internal iliac artery (IIA) with the covered endovascular reconstruction of the iliac bifurcation (CERIB) technique. This is a single-center, retrospective analysis of prospectively collected data of patients that underwent EVAR either for intact abdominal aortic aneurysm (AAA) or previous failed EVAR from December 2022 up to September 2023. Indications for treatment were presence of common iliac artery aneurysm (CIAA), short CIA, or endoleak type Ib (ETIb). For the distal sealing zone, we used balloon-expandable covered stent (BXCS). Primary outcomes were technical success and first-month patency rate. Secondary outcomes were endoleak and re-intervention rate. Sixteen patients being treated with 20 CERIBs were included in the study. Four patients had a previous failed EVAR, while 3 patients were treated urgently for a symptomatic para-renal aneurysm. The indications for treatment were EIb (n=2), short CIA (n=4), CIAA with narrow lumen (n=3), and CIA aneurysm (n=11). Platforms that were used were the Cook Zenith Alpha (n=5), Gore C3 (n=2 and 3 limbs), Endurant IIs (n=2, and 3 limbs), and a t-branch device (n=3). Technical success rate was 100% with no adjunctive procedure. No death or re-intervention was recorded for all patients at postoperative 30-day period and at 6 months for 2 patients. At first-month CTA, patency rate was 100% (20/20), while in 2 patients that had 6-month CTA, the patency was also 100% (2/2). No kinking or stenosis was also noted. Two patients had ETIII after branched EVAR (BEVAR), 2 patients had ETII, and 1 patient had gutter ET in the area of the CERIB. The CERIB technique seems to be effective and safe in the early period. It is suitable with a variety of commercial endograft platforms. It may be a valuable alternative to iliac branch devices when there are anatomical considerations. Longer follow-up is needed to conclude for long-term patency and durability. The distal landing zone in iliac arteries represents an important issue during EVAR while it is important to preserve blood flow in the internal iliac artery. The covered endovascular reconstruction of the iliac bifurcation (CERIB) technique is a technique for the preservation of internal iliac arteries during EVAR, while it is suitable with a variety of commercial endograft platforms. The CERIB technique seems to be effective and safe in the early period. It may be valuable alternative to iliac branch devices when there are anatomical considerations.

Aging related changes in cardiovascular system in healthy female population: photoplethysmography method and DFA analysis

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Science Technological Development and Innovation Background The cardiovascular system undergoes dynamic changes during the biological aging in humans, leading to chronic cardiovascular and cerebrovascular diseases. Purpose Developing the novel method for non-invasive monitoring of age induced changes in arterial vessels. Methodology The pilot study was performed on 58 women, in good health, non-smokers, between the ages of 20 and 70, divided into three age groups. All subjects underwent arterial blood pressure measurement using a photoplethysmography sensor. Recordings were performed in left carotid artery and the left index finger area. Arterial blood flow waveform was then analyzed using DFA analysis, calculating the values of the scalar coefficients α1 and α2. Based on the waveform time interval shift between the standing and supine positions, the pulse wave velocity (PWV) ratio was determined. Results Systolic and diastolic arterial pressure showed a slight linear increase with the age, but without significant difference between the three age categories (p > 0.5). Also, the PWV ratio between the supine and standing positions did not show a statistically significant increase between the age groups. Only scalar coefficients ratio α1/α2 demonstrated a significant difference in value between all age categories. Conclusion In subjects included in this pilot study, only the scalar coefficients ratio varied significantly with the age, indicating the occurrence of structural changes in the cardiovascular system caused by biological aging.

Multifaceted simulation: Finite volume and finite element modeling of blood flow in multiple stenosed arteries

Cardiovascular illnesses are a primary global health concern because they are frequently brought on by arterial stenosis. The complicated hemodynamics of blood flow via elliptically shaped arteries with numerous stenotic lesions along their top and bottom walls are examined in this paper. Carreau fluid model is used with Navier–Stokes equations in this study. The complete comparative study is done by using the Finite Element and Finite Volume Methods. This study uses commercial software to examine blood flow velocity, pressure and temperature distributions under various physiological situations at Reynolds number 30. Our results illuminate the interaction between flow dynamics, stenosis characteristics, and arterial geometry. The novelty of the work is to investigate how stenosis size, shape, and location affect pressure gradients, and flow disturbances. These observations provide helpful direction for understanding disease progression, designing treatments, and possibly new stent designs. The future direction of this research may involve further exploration of the interplay between hemodynamics and arterial stenosis by incorporating advanced computational models. Additionally, studies focusing on in vivo validation and clinical applications could enhance the translational impact of the findings. Collaborations between researchers, clinicians, and engineers may pave the way for personalized treatment strategies and innovations in cardiovascular care based on a deeper understanding of the intricate dynamics within diseased arteries.

Effects of late gestational nutrient restriction on uterine artery blood flow, placental size, and cotyledonary mRNA expression in primiparous beef females.

Fall-calving primiparous beef females [body weight (BW): 451 ± 28 (SD) kg; body condition score (BCS): 5.4 ± 0.7] were individually-fed either 100% (control; CON; n = 13) or 70% (nutrient restricted; NR; n = 13) of metabolizable energy and metabolizable protein requirements for maintenance, pregnancy, and growth from day 160 of gestation to parturition. Doppler ultrasonography of both uterine arteries was conducted pre-treatment and every 21 d from days 181 to 265 of gestation. Expelled placentas were collected, and ipsilateral cotyledonary tissue was sampled to assess relative messenger ribonucleic acid (mRNA) expression. Placentas were separated into ipsilateral and contralateral sides, dissected (cotyledonary vs. intercotyledonary), and dried. Data were analyzed with nutritional plane, treatment initiation date, and calf sex (when P < 0.25) as fixed effects. Uterine blood flow included day and nutritional plane × day as repeated measures. We previously reported that post-calving, NR dams weighed 64kg less and were 2.0 BCS lower than CON, but calf birth weight was not affected. Maternal heart rate was less (P < 0.001) for NR dams than CON after nutritional planes began. Nutritional plane did not affect (P ≥ 0.20) uterine artery hemodynamics, but all variables were affected (P ≤ 0.04) by day. Contralateral cotyledonary and placental weight were less (P ≤ 0.04) and contralateral intercotyledonary weight and number of cotyledons tended to be less (P ≤ 0.10) for NR dams than CON, but ipsilateral and whole placental weights were not affected (P ≥ 0.13). Ipsilateral placental weight as a percentage of total placental weight was greater (P = 0.03) for NR dams than CON. Whole placental cotyledonary:intercotyledonary weight was less (P = 0.01) for NR dams than CON. Placental efficiency was not affected (P = 0.89) by nutritional plane. Cotyledonary relative mRNA expression of GLUT3 and SNAT2 was greater (P ≤ 0.05) and relative expression of GLUT1, GLUT4, and NOS3 tended to be greater (P ≤ 0.07) for NR dams than CON. Nutritional plane did not affect (P ≥ 0.13) relative mRNA expression of GLUT5, 4F2hc, CAT1, LAT1, LAT2, VEGFA, FLT1, KDR, GUCY1B3, and PAG2. Despite less contralateral placental growth, beef heifers experiencing late gestational nutrient restriction maintained uterine artery blood flow and total placental mass and had 4 nutrient transporters and 1 angiogenic factor upregulated in cotyledons, all which likely contributed to conserving fetal growth.

#2169 Transplant renal artery stenosis in recipients with resistant arterial hypertension

Abstract Background and Aims Transplant Renal Artery Stenosis (TRAS) is a vascular complication after kidney transplantation. It worsens the prognosis of the graft and the patient's life. The aim was to study the incidence of TRAS as a cause of resistant arterial hypertension in kidney transplant recipients in the Republic of Belarus and the efficiency of its endovascular treatment. Method The study included 187 kidney transplant recipients. Blood pressure of 72 (38.5%) patients was less than 130/80 mmHg without taking antihypertensive drugs. Arterial hypertension was diagnosed in 115 (61.5%) recipients. The study included clinical, laboratory and instrumental methods (24-hour blood pressure monitoring, Doppler ultrasound, graft scintigraphy with captopril). Results 31 (16.6%) recipients needed to take one antihypertensive drug, 43 (23.0%)—2 drugs, 41 (21.9%)—3 or more. 17 (9.1%) recipients did not have target blood pressure correction while taking more than 4 antihypertensive drugs. There was decreased blood flow in the graft artery with a peak systolic velocity &amp;gt; 200 cm/s in 14 (7.5%) cases. These patients were submitted to the graft nephroscintigraphy with caplopril where 8 grafts (4.3%) were diagnosed signs of TRAS. These recipients were submitted to the renal angiography with the injection of 150 (100; 200) ml of contrast agent. 5 (2.7%) recipients were diagnosed with hemodynamically significant TRAS of more than 70 (65; 75) % and received percutaneous transluminal angioplasty and stenting. All these patients had a decrease of glomerular filtration rate and resistant arterial hypertension before operation. The average age of the patients with TRAS was 57.4 ± 11.0 years, the period after transplantation was 11 ± 3 months. Their blood tests did not show dyslipidemia, but 4 out of 5 cases had diabetes mellitus. Their postoperative period had no complications. The patient was placed on dual antiplatelet therapy with aspirin and clopidogrel. There was an increase in glomerular filtration rate by 27 ± 7 ml/min/1.73 m2 and a decrease in systolic blood pressure by 40 (40; 45) mm Hg in the early postoperative period. Graft artery stenting allowed reducing the number of antihypertensive drugs to one tablet in 4 out of 5 patients. Conclusion Transplant Renal Artery Stenosis is a rare but significant complication of the late postoperative period that may cause resistant hypertension in kidney transplant recipients. Timely identification and stenting of the graft artery improves the graft functioning and reduces blood pressure.

#2741 The interplay between donor &amp; recipient factors, outcomes, and transplant artery flow volume as measured by phase-contrast magnetic resonance imaging

Abstract Background and Aims Cardiovascular health and kidney transplant health are inter-connected [1]. Phase-contrast magnetic resonance imaging (PC-MRI) is a non-invasive means of quantifying blood flow volume within vasculature. Its utility for the assessment of blood flow volumes within the transplant renal artery has not been explored. The aims of this study were to determine if: (A) flow in the transplant artery is influenced by donor and recipients factors, (B) flow in the transplant artery is related to or influences clinical outcomes for transplant recipients. Method Analysis of PC-MRI sequences obtained during 218 kidney transplant magnetic resonance angiograms (MRA) performed at a single centre between 2019 and 2021 was undertaken. All scans were clinically indicated and requested by clinicians to investigate for transplant renal artery stenosis (TRAS). Baseline clinical and demographic data and subsequent clinical outcome data were collected for all study participants. Median follow up was 49 (IQR 40–54) months. For Kaplan-Meier survival analyses, comparison of clinical outcomes by interquartile range of flow volumes was performed, whereby quartile one comprised subjects with the lowest transplant artery blood flow volumes. Statistical analysis was performed using MedCalc Statistical Software version 22.013. Results In this study of 218 subjects, 49 (22.4%) had features of possible TRAS identified on initial MRA. TRAS was subsequently confirmed via intra-arterial digital subtraction angiography in 19 (8.7%) cases. The majority of participants were male 150/218 (68.8%). The commonest cause of ESKD was diabetic kidney disease at 71/218 (32.6%). Living donor transplant recipients were 35/218 (11.5%) of the study population. The median donor age was 55 (IQR 44–65) years. The median time from ESKD to transplantation was 25 (IQR 9–53) months. The median time from transplantation to PC-MRI for all participants was 322 (IQR 81–1744) days; for participants who were ultimately diagnosed with TRAS it was 169 (IQR 76–262) days. The median age of recipients at time of PC-MRI was 56 (IQR 45–64) years. Overall, the mean transplant artery flow volume was 0.41 L/min (95% CI 0.39–0.45 L/min). Rank correlation between age of donor and flow in the transplant artery (L/min) showed r = −0.25 (95% CI −0.37 - −0.12) P = 0.0002. Rank correlation between age of recipient at time of PC-MRI and flow in the transplant artery (L/min) showed r = −0.37 (95% CI −0.48 to −0.25) P ≤ 0.0001. Rank correlation between flow in the transplant artery (L/min) and estimated glomerular filtration rate (mL/min/1.73 m2) showed r = 0.43 (95% CI 0.31–0.53) P &amp;lt; 0.0001. Univariable linear regression analysis of flow in the transplant artery (L/min) and estimated glomerular filtration rate (mL/min/1.73 m2) was R2 0.14, DF regression = 1 DF residual = 214, F = 34.7, P &amp;lt; 0.0001 (Fig. 1). Overall, 35 (16.1%) participants experienced kidney transplant failure and 42 (19.3%) participants died within the study follow up period. Kaplan-Meier analysis showed no significant difference in kidney transplant survival between four groups categorized according to transplant artery flow volumes, logrank test P = 0.93 (Fig. 2A). Subjects in the first quartile were at greater risk of death, logrank test P = 0.01, HR 4.36 (95% CI 1.77–10.74) compared with fourth quartile (Fig. 2B) Conclusion This study has demonstrated that both older donor age and older recipient age negatively correlate with transplant artery flow, and that transplant artery flow is positively correlated and predicts estimated glomerular filtration rate. Finally, recipients with low transplant artery flow volume are at greater risk of death. Neither cause nor effect of low blood flow volume have been elucidated in this study. However, improving transplant blood flow by optimising cardiovascular health may have a positive impact on outcomes for people with kidney transplants and warrants further study.

Arterial Blood Flow and Effects on Limb Tissue Perfusion During Endoshunting of the Common Iliac Artery in an Experimental Porcine Model

Arterial Blood Flow and Effects on Limb Tissue Perfusion During Endoshunting of the Common Iliac Artery in an Experimental Porcine Model

Computational fluid dynamics modeling of coronary artery blood flow using OpenFOAM: Validation with the food and drug administration benchmark nozzle model.

Cardiovascular disease (CVD), a global health concern, particularly coronary artery disease (CAD), poses a significant threat to well-being. Seeking safer and cost-effective diagnostic alternatives to invasive coronary angiography, noninvasive coronary computed tomography angiography (CCTA) gains prominence. This study employed OpenFOAM, an open-source Computational Fluid Dynamics (CFD) software, to analyze hemodynamic parameters in coronary arteries with serial stenoses. Patient-specific three-dimensional (3D) models from CCTA images offer insights into hemodynamic changes. OpenFOAM breaks away from traditional commercial software, validated against the FDA benchmark nozzle model for reliability. Applying this refined methodology to seventeen coronary arteries across nine patients, the study evaluates parameters like fractional flow reserve computed tomography simulation (FFRCTS), fluid velocity, and wall shear stress (WSS) over time. Findings include FFRCTS values exceeding 0.8 for grade 0 stenosis and falling below 0.5 for grade 5 stenosis. Central velocity remains nearly constant for grade 1 stenosis but increases 3.4-fold for grade 5 stenosis. This research innovates by utilizing OpenFOAM, departing from previous reliance on commercial software. Combining qualitative stenosis grading with quantitative FFRCTS and velocity measurements offers a more comprehensive assessment of coronary artery conditions. The study introduces 3D renderings of wall shear stress distribution across stenosis grades, providing an intuitive visualization of hemodynamic changes for valuable insights into coronary stenosis diagnosis.

Propulsive study of blood flow with heat transfer enhancement connection to ferro copper magnetized nanoparticles in converging tapered stenosed arterial surface

To investigate the effects of magnetic fields and variously structured nanoparticles in narrowing, stenosed arteries, an arterial flow model is incorporated. The aim of this study here is to achieve more realistic results by modeling and simulating the arterial blood flow system with the nanoparticles and shape factor of the nanoparticles. The study of blood flow in tapered stenosed arteries with nanoparticles involves understanding the dynamics of blood circulation in vessels having application in drug delivery. Nanoparticles with specific shape factors can enhance imaging modalities like MRI, CT or ultrasound diagnosing tumor. Metallic nanoparticles in various shapes utilizing water as the base fluid have not yet been considered. Imagine a symmetrical radially but axially nonsymmetric constriction for the blood flow. Along with taking into account the regularity in the sequence of distributing the wall shear stress as well as resistance impedance, the study also takes into account a rise in these readings as the stenosis worsens. For speed, resistive impedance, wall shear and shearing forces at the stenosis throat, results have been computed in exact form. For various Cu-water-relevant parameters, the visual results of several types of converging tapering arteries have been assessed.

Оценка кровоснабжения миокарда методом допплерографии коронарных артерий после пантовой бальнеотерапии

The purpose of this study was to objectively assess the effectiveness of rehabilitation using balneotherapy with velvet antler products. Materials and methods. Doppler assessment of coronary artery blood flow was performed. As a reference vessel, we chose the anterior descending artery, which is the largest branch of the left coronary artery and has its own numerous branches providing blood supply to the main part of the functionally active left ventricle myocardium. We studied the following groups of patients, whose rehabilitation included balneotherapy with velvet antler products: 1) 48 subjects with stage 2 arterial hypertension and 2) 49 subjects with coronary artery disease after balloon angioplasty and coronary artery stenting. In addition to balneotherapy, group 1 received standard hypotensive therapy with angiotensin-converting-enzyme inhibitors, beta blockers and thiazide diuretics, while group 2 was given indirect anticoagulants, beta blockers and new generation statins. Before and upon completing the treatment course, each patient’s peak blood flow velocity was measured, as well as blood flow integral in the proximal segment of the anterior descending artery. Results. After the balneotherapy course, most patients in both groups showed quiet and increased activation of high reactivity level. According to our observations, patients tolerated the treatment well. Initially, peak blood flow velocity and blood flow integral were recorded within the range of 28–45 cm/s (mean: 36.9 ± 4.4 cm/s) and 9–14 cm (mean: 11.00 ± 1.25 cm), respectively, without between-group differences. After the multimodality treatment that included balneotherapy with velvet antler products, these parameters were recorded within the range of 39–52 cm/s (mean: 45.7 ± 3.5 cm/s) and 11–16 cm (mean: 14.0 ± 1.3 cm), respectively, with no between-group differences either. The increase in peak blood flow velocity was statistically significant (p ˂ 0.001). Thus, balneotherapy using innovative velvet antler products combined with medication treatment and physical therapy, presumably, contributed to improving coronary blood circulation in patients with stable ischemic heart disease and arterial hypertension.

Ex vivo validation of magnetically actuated intravascular untethered robots in a clinical setting

Intravascular surgical instruments require precise navigation within narrow vessels, necessitating maximum flexibility, minimal diameter, and high degrees of freedom. Existing tools often lack control during insertion due to undesirable bending, limiting vessel accessibility and risking tissue damage. Next-generation instruments aim to develop hemocompatible untethered devices controlled by external magnetic forces. Achieving this goal remains complex due to testing and implementation challenges in clinical environments. Here we assess the operational effectiveness of hemocompatible untethered magnetic robots using an ex vivo porcine aorta model. The results demonstrate a linear decrease in the swimming speed of untethered magnetic robots as arterial blood flow increases, with the capability to navigate against a maximum arterial flow rate of 67 mL/min. The untethered magnetic robots effectively demonstrate locomotion in a difficult-to-access target site, navigating through the abdominal aorta and reaching the distal end of the renal artery.

Lower arterial cerebral blood flow is associated with worse neuroinflammation and immunomodulation composite proteomic scores

BackgroundBrain hypoperfusion is linked with worse physical, cognitive and MRI outcomes in multiple sclerosis (MS). Understanding the proteomic signatures related to hypoperfusion could provide insights into the pathophysiological mechanism. Methods140 people with MS (pwMS; 86 clinically isolated syndrome (CIS)/relapsing-remitting (RRMS) and 54 progressive (PMS)) were included. Cerebral arterial blood flow (CABF) was determined using ultrasound Doppler measurement as the sum of blood flow in the bilateral common carotid arteries and vertebral arteries. Proteomic analysis was performed using the Multiple Sclerosis Disease Activity (MSDA) test assay panel performed on the Olink™ platform. The MSDA test measures the concentrations of 18 proteins that are age and sex-adjusted. It utilizes a stacked classifier logistic regression model to determine 4 disease pathway scores (immunomodulation, neuroinflammation, myelin biology, and neuroaxonal integrity) as well as an overall disease activity score (1 to 10). MRI measures of T2 lesion volume (LV) and whole brain volume (WBV) were derived. ResultsThe pwMS were on average 54 years old and had an average CABF of 951 mL/min. There were no differences in CABF between CIS/RRMS vs. PMS groups. Lower CABF levels were correlated with the overall disease activity score (r = -0.26, p = 0.003) and with the neuroinflammation (r = -0.29, p = 0.001), immunomodulation (r = -0.26, p = 0.003) and neuroaxonal integrity (r = -0.23, p = 0.007) pathway scores. After age and body mass index (BMI)-adjustment, lower CABF remained associated with the neuroinflammatory (r = -0.23, p = 0.011) and immunomodulation (r = -0.20, p = 0.024) pathway scores. The relationship between CABF and the neuroinflammation pathway score remained significant after adjusting for T2-LV and WBV (p = 0.038). Individual analyses identified neurofilament light chain, CCL-20 and TNFSF13B as contributors. When compared to the highest quartile (>1133.5 mL/min), the pwMS in the lowest CABF quartile (<764 mL/min) had greater overall disease activity score (p = 0.003), neuroinflammation (p = 0.001), immunomodulation (p = 0.004) and neuroaxonal integrity pathway scores (p = 0.007). ConclusionLower cerebral arterial perfusion in MS is associated with changes in neuroinflammatory/immunomodulation pathways and their respective proteomic biomarkers. These findings may suggest a relationship between the hypoperfusion and pro-inflammatory MS changes rather than being merely an epiphenomenon subsequent to lower energy demands.

Evaluation of the blood flow in reconstructed gastric tube and its relation to anastomosis leakage.

Anastomotic leakage in esophageal cancer surgery may be reduced by evaluating the blood flow to the reconstructed organ, but quantitative evaluation of arterial and venous blood flow is difficult. This study aimed to quantitatively assess blood flow using a new technique, as well as determine the relationship between the blood flow in the gastric tube and anastomotic leakage using near-infrared spectroscopy. This single-center, observational study included 50 patients aged 51-82years who underwent radical esophagectomy with gastric tube reconstruction for esophageal cancer between June 2022 and January 2023. Regional tissue oxygen saturation was measured at the antrum (point X), the anastomotic point (point Z), and the midpoint between points X and Z (point Y) before and after gastric tube formation. These three points of oxygen saturation were investigated in relation to anastomotic leakage. When comparing the presence of leakage to its absence, regional tissue oxygen saturation at points X and Z after gastric tube formation was significantly lower (X: p = 0.03, Z: p = 0.02), with the decreasing rate significantly higher at point Z (p = 0.01). There was no significant difference in the decreasing rate of regional tissue oxygen saturation between points X and Y (X: p = 0.052, Y: p = 0.83). Regional tissue oxygen saturation levels may be useful for measuring blood flow and could be a predictor of anastomotic leakage.

Aging in females has minimal effect on changes in celiac artery blood flow during dynamic light-intensity exercise.

Blood flow to the active muscles and arterial blood pressure (ABP) increase during dynamic exercise, whereas blood flow to inactive organs (e.g., splanchnic organs and inactive limbs) declines. Aging leads to exaggerated ABP responses to exercise in females, but whether this is related to greater splanchnic vasoconstriction is unknown. This study sought to clarify the effect of aging in females on celiac artery blood flow during dynamic light-intensity exercise. Twelve healthy young females (YF: 20 ± 2 yr, mean ± SD) and 12 healthy older females (OF: 71 ± 4 yr) performed dynamic knee-extension and knee-flexion exercises at 30% of heart rate reserve for 4 min. The absolute changes from baseline (Δ) for mean arterial blood pressure (MAP), celiac artery mean blood flow (celMBF), and celiac vascular conductance (celVC) during exercise were calculated. ABP was measured using an automated sphygmomanometer, and celMBF was recorded by Doppler ultrasonography. The increase in MAP during exercise was greater in OF than in YF (YF: +14 ± 7 mmHg, OF: +24 ± 13 mmHg, P = 0.028). The celMBF decreased during exercise in both groups, but there was no significant difference in the response between YF and OF (YF: -93.0 ± 66.1 mL/min, OF: -89.6 ± 64.0 mL/min, P = 0.951). The celVC also decreased during exercise and remained lower than baseline during exercise. However, the response was not different between YF and OF (YF: -1.8 ± 1.0 mL/min/mmHg, OF: -1.5 ± 0.6 mL/min/mmHg, P = 0.517). These results demonstrate that aging in females has minimal influence on splanchnic artery hemodynamic responses during dynamic light-intensity exercise, suggesting that exaggerated ABP responses during exercise in OF are not due to greater splanchnic vasoconstriction.NEW & NOTEWORTHY During exercise, the splanchnic arteries vasoconstrict, contributing to blood flow redistribution and the blood pressure response. Blood pressure responses to exercise are exaggerated with aging in females; however, the physiological mechanism responsible has not been clarified. We show that celiac artery blood flow changes during light-intensity dynamic exercise do not differ with age in females. This indicates the exaggerated blood pressure to exercise with aging is likely not due to a difference in splanchnic vasoconstriction.

Ultrasound vector mapping of common femoral artery blood flow in normal and early-stage stenosis

It is assumed that the wall shear stress (WSS), which determines the function of the endothelium, is constant along the arterial bed. The assessment of turbulence, blood flow velocity in the arterial system in healthy (13 patients) and in patients with the initial form of atherosclerosis in the femoral artery (42 patients) was discussed. The study quantified blood flow in the common femoral artery using V Flow with visualization of blood flow with a high frame rate. The results obtained in the femoral arteries were evaluated by the wall shear rate, velocity profile and oscillation index (OSI). It was shown that the average value of WSSmean in the femoral artery in healthy and in patients with stenosis &lt;30–35% is 0.9± 0.4 – 0.91±0.4 Pa and does not significantly differ. The wall thickness in the common femoral artery in patients with the initial form of atherosclerosis was 0.9–1.1 mm, and in healthy patients 0.8–0.9 mm. The correlation between the parameters was evaluated by nonparametric analysis of Kendall’s Taub. It was revealed that there is no correlation between WSSmean and blood flow velocity (Vs) in both healthy and patients with the initial form of atherosclerosis.