Blood Flow Velocity Research Articles

Effects of short-term dietary nitrate supplementation on exercise and coronary blood flow responses in patients with peripheral artery disease.

Peripheral arterial disease (PAD) is a prevalent vascular disorder characterized by atherosclerotic occlusion of peripheral arteries, resulting in reduced blood flow to the lower extremities and poor walking ability. Older patients with PAD are also at a markedly increased risk of cardiovascular events, including myocardial infarction. Recent evidence indicates that inorganic nitrate supplementation, which is abundant in certain vegetables, augments nitric oxide (NO) bioavailability and may have beneficial effects on walking, blood pressure, and vascular function in patients with PAD. We sought to determine if short-term nitrate supplementation (via beetroot juice) improves peak treadmill time and coronary hyperemic responses to plantar flexion exercise relative to placebo (nitrate-depleted juice) in older patients with PAD. The primary endpoints were peak treadmill time and the peak coronary hyperemic response to plantar flexion exercise. Eleven PAD patients (52-80 yr.; 9 men/2 women; Fontaine stage II) were randomized (double-blind) to either nitrate-rich (Beet-IT, 0.3 g inorganic nitrate twice/day; BRnitrate) or nitrate-depleted (Beet-IT, 0.04 g inorganic nitrate twice/day, BRplacebo) beetroot juice for 4 to 6 days, followed by a washout of 7 to 14 days before crossing over to the other treatment. Patients completed graded plantar flexion exercise with their most symptomatic leg to fatigue, followed by isometric handgrip until volitional fatigue at 40% of maximum on day 4 of supplementation, and a treadmill test to peak exertion 1-2 days later while continuing supplementation. Hemodynamics and exercise tolerance, and coronary blood flow velocity (CBV) responses were measured. Although peak walking time and claudication onset time during treadmill exercise did not differ significantly between BRplacebo and BRnitrate, the diastolic blood pressure response at the peak treadmill walking stage was significantly lower in the BRnitrate condition. Increases in CBV from baseline to peak plantar flexion exercise after BRplacebo and BRnitrate showed a trend for a greater increase in CBV at the peak workload of plantar flexion with BRnitrate (p = 0.06; Cohen's d = 0.56). Overall, these preliminary findings suggest that inorganic nitrate supplementation in PAD patients is safe, well-tolerated, and may improve the coronary hyperemic and blood pressure responses when their calf muscles are most predisposed to ischemia.Clinical trial registration:https://clinicaltrials.gov/, identifier NCT02553733.

Cerebral Microvascular Density, Permeability of the Blood-Brain Barrier, and Neuroinflammatory Responses Indicate Early Aging Characteristics in a Marfan Syndrome Mouse Model.

Marfan Syndrome (MFS) is a connective tissue disorder due to mutations in fibrillin-1 ( Fbn1 ), where a Fbn1 missense mutation ( Fbn1 C1039G/+ ) can result in systemic increases in the bioavailability and signaling of transforming growth factor-β (TGF-β). In a well-established mouse model of MFS ( Fbn1 C1041G/+ ), pre-mature aging of the aortic wall and the progression of aortic root aneurysm are observed by 6-months-of-age. TGF-β signaling has been implicated in cerebrovascular dysfunction, loss of blood-brain barrier (BBB) integrity, and age-related neuroinflammation. We have reported that pre-mature vascular aging in MFS mice could extend to cerebrovasculature, where peak blood flow velocity in the posterior cerebral artery (PCA) of 6-month-old (6M) MFS mice was reduced, similarly to 12-month-old (12M) control mice. Case studies of MFS patients have documented neurovascular manifestations, including intracranial aneurysms, stroke, arterial tortuosity, as well as headaches and migraines, with reported incidence of pain and chronic fatigue. Despite these significant clinical observations, investigation into cerebrovascular dysfunction and neuropathology in MFS remains limited. Using 6M-control ( C57BL/6 ) and 6M-MFS ( Fbn1 C1041G/+ ) and healthy 12M-control male and female mice, we test the hypothesis that abnormal Fbn1 protein expression is associated with altered cerebral microvascular density, BBB permeability, and neuroinflammation in the PCA-perfused hippocampus, all indicative of a pre-mature aging brain phenotype. Using Glut1 staining, 6M-MFS mice and 12M-CTRL similarly present decreased microvascular density in the dentate gyrus (DG), cornu ammonis 1 (CA1), and cornu ammonis 3 (CA3) regions of the hippocampus. 6M-MFS mice exhibit increased BBB permeability in the DG, CA1, and CA3 as evident by Immunoglobulin G (IgG) staining, which was more comparable to 12M-CTRL mice. 6M-MFS mice show a higher number of microglia in the hippocampus compared to age-matched control mice, a pattern resembling that of 12M-CTRL mice. This study represents the first known investigation into neuropathology in a mouse model of MFS and indicates that the pathophysiology underlying MFS leads to a systemic pre-mature aging phenotype. This study is crucial for identifying and understanding MFS-associated neurovascular and neurological abnormalities, underscoring the need for research aimed at improving the quality of life and managing pre-mature aging symptoms in MFS and related connective tissue disorders.

Hydroxyurea to prevent brain injury in children with sickle cell disease (HU Prevent)-A randomized, placebo-controlled phase II feasibility/pilot study.

Central nervous system (CNS) injury is common in sickle cell disease (SCD) and occurs early in life. Hydroxyurea is safe and efficacious for treatment of SCD, but high-quality evidence from randomized trials to estimate its neuroprotective effect is scant. HU Prevent was a randomized (1:1), double-blind, phase II feasibility/pilot trial of dose-escalated hydroxyurea vs. placebo for the primary prevention of CNS injury in children with HbSS or HbS-β0-thalassemia subtypes of SCD age 12-48 months with normal neurological examination, MRI of the brain, and cerebral blood flow velocity. We hypothesized that hydroxyurea would reduce by 50% the incidence of CNS injury. Two outcomes were compared: primary-a composite of silent cerebral infarction, elevated cerebral blood flow velocity, transient ischemic attack, or stroke; secondary-a weighted score estimating the risk of suffering the consequences of stroke (the Stroke Consequences Risk Score-SCRS), based on the same outcome events. Six participants were randomized to each group. One participant in the hydroxyurea group had a primary outcome vs. four in the placebo group (incidence rate ratio [90% CI] 0.216 [0.009, 1.66], p = .2914) (~80% reduction in the hydroxyurea group). The mean SCRS score was 0.078 (SD 0.174) in the hydroxyurea group, 0.312 (SD 0.174) in the placebo group, p = .072, below the p-value of .10 often used to justify subsequent phase III investigations. Serious adverse events related to study procedures occurred in 3/41 MRIs performed, all related to sedation. These results suggest that hydroxyurea may have profound neuroprotective effect in children with SCD and support a definitive phase III study to encourage the early use of hydroxyurea in all infants with SCD.

Use of 3D Echocardiography Facilitates Analysis of Thrombolytic Efficacy in Patients With Persistent Atrial Fibrillation.

This study seeks to identify the anticoagulant efficacy of rivaroxaban treatment on thrombi detected using echocardiography of the left atrial appendage in 275 patients with persistent atrial fibrillation. During follow-up after 9-24 weeks of rivaroxaban treatment, patients were divided into "effective group" (n = 143) and "ineffective group" (n = 132) according to the thrombolytic effect of the drug. Left atrial diameter (LAD), left atrial ejection fraction (LAEF), left ventricular ejection fraction (LVEF), mean diameter of left atrial appendage (LAAD mean ), angle between left atrial appendage and left atrium (LAA-A), velocity of blood flow in left atrial appendage (LAA-v), and thrombus size were compared before and after drug administration. Following treatment, LAEF, LVEF, and LAA-v values were greater and LAD and LAAD mean values were lower in the effective ( P < 0.05). Logistic regression analysis showed significant correlations of LAD, LAEF, LVEF, LAA-A, and LAA-v with anticoagulant efficacy ( P < 0.05). The efficacy of rivaroxaban in treatment of left atrial auricular thrombosis in patients with persistent AF was correlated with LAD, LAEF, LVEF, LAA-A, and LAA-v. Multivariate logistic regression analysis further revealed LAEF [odds ratio (OR) 1.7, 95% confidence interval (CI), 0.45-16.9, P = 0.008], 3D-EF (OR 6.4, 95% CI, 1.06-16.9, P = 0.039) and left ventricular global longitudinal strain (OR 18.0, 95% CI, 1.38-35.68, P = 0.028) as factors related to left atrial appendage thrombus. Echocardiography with global longitudinal strain assessment could be effectively utilized to evaluate the functional parameters of LAA and thus aid in predicting the safety of rivaroxaban as an anticoagulation agent.

Multiphase patient-specific simulations to study fibrillation-induced thrombosis in the left atrial appendage

Thrombosis commonly develops in the left atrial appendage of patients with atrial fibrillation. The formation of blood clots in atrial appendage is a complex process, which depends on the shape of the appendage, the velocity of blood flow, the concentrations of red blood cells, platelets, and coagulation, among other factors. In this work, we present a new methodology to identify the key factors contributing to clot formation in the left atrial appendage during atrial fibrillation. The new methodology combines computed tomography imaging, computational fluid dynamics, mesh processing, and multiphase thrombosis modeling. We begin by running simulations to investigate flow patterns inside the left atrial appendages with realistic geometries. Our simulations suggest that at the entrance of the left atrial appendage, the flow forms vortices, which can intrude inside the appendage depending on the phases of the cardiac cycle. Next, we introduce blood coagulation and consider different scenarios corresponding to physiological values of blood flow velocity, geometry of the left atrial appendage, and hematocrit values. Numerical results suggest that the chances of clot formation are higher in the “cactus” geometry than in the “chicken-wing” one, in agreement with the literature. Furthermore, they suggest that slower flow circulation facilitates the development of a clot in the depth of the left atrial appendage. Slower blood movement also favors the procoagulant activity of platelets, while faster flow circulation enhances the procoagulant effect from erythrocytes. Finally, our simulations show that increased hematocrit upregulates the generation of fibrin polymer, regardless of flow velocity.

Blunted brachial blood flow velocity response to acute mental stress in PTSD females.

Post-traumatic stress disorder (PTSD) is associated with increased cardiovascular disease (CVD) risk. Compared with males, females are twice as likely to develop PTSD after trauma exposure, and cardiovascular reactivity to stress is a known risk factor for CVD. We aimed to examine hemodynamic responses to acute mental stress in trauma-exposed females with and without a clinical diagnosis of PTSD. We hypothesized that females with PTSD would have higher heart rate (HR), blood pressure (BP), and lower blood flow velocity (BFV) responsiveness compared with controls. We enrolled 21 females with PTSD and 21 trauma-exposed controls. We continuously measured HR using a three-lead electrocardiogram, BP using finger plethysmography, and brachial BFV using Doppler ultrasound. All variables were recorded during 10 min of supine rest, 5 min of mental arithmetic, and 5 min of recovery. Females with PTSD were older, and had higher BMI and higher resting diastolic BP. Accordingly, age, BMI, and diastolic BP were covariates for all repeated measures analyses. Females with PTSD had a blunted brachial BFV response to mental stress (time × group, p = 0.005) compared with controls, suggesting greater vasoconstriction. HR and BP responses were comparable. In conclusion, our results suggest early impairment of vascular function in premenopausal females with PTSD.

Haemodynamic effects of non-Newtonian fluid blood on the abdominal aorta before and after double tear rupture

ObjectivesIntimal tears caused by aortic dissection can weaken the arterial wall and lead to aortic aneurysms. However, the effect of different tear states on the blood flow behaviour remains complex. This study uses a novel approach that combines numerical haemodynamic simulation with in vitro experiments to elucidate the effect of arterial dissection rupture on the complex blood flow state within the abdominal aneurysm and the endogenous causes of end-organ malperfusion. Materials and methodsBased on the CT imaging data and clinical physiological parameters, the overall arterial models including aortic dissection and aneurysm with single tear and double tear were established, and the turbulence behaviours and haemodynamic characteristics of arterial dissection and aneurysm under different blood pressures were simulated by using non-Newtonian flow fluids with the pulsatile blood flow rate of the clinical patients as a cycle, and the results of the numerical simulation were verified by in vitro simulation experiments. ResultsHemodynamic simulations revealed that the aneurysm and single-tear false lumen generated a maximum pressure of 320.591 mmHg, 267 % over the 120 mmHg criterion. The pressure differential generates reflux, leading to a WSS of 2247.9 Pa at the TL inlet and blood flow velocities of up to 6.41 m/s inducing extend of the inlet. DTD Medium FL instantaneous WP above 120 mmHg Standard 151 % Additionally, there was 82.5 % higher flow in the right iliac aorta than in the left iliac aorta, which triggered malperfusion. Thrombus was accumulated distal to the tear and turbulence. These results are consistent with the findings of the in vitro experiments. ConclusionsThis study reveals the haemodynamic mechanisms by which aortic dissection induces aortic aneurysms to produce different risk states. This will contribute to in vitro simulation studies as a new fulcrum in the process of moving from numerical simulation to clinical trials.

The impact of left atrial morphology on thrombosis risk in atrial fibrillation

Atrial fibrillation (AF) is an arrhythmia disease that can disrupt the movement of the left atrium (LA), which will facilitate thromboembolism in LA and further exacerbate the stroke risk. The left atrial appendage (LAA) is a vital site for thrombus formation. The morphology of the LAA is believed to have a profound effect on thrombosis. However, due to the limitation of observation and monitoring methods, the mechanism of this effect is still unrevealed. Virchow's triad is a theory of thrombogenic mechanisms, stating that endothelial injury, blood hypercoagulability, and blood stasis are the three main factors involved in thrombus formation. In this study, we conducted personalized simulation analyses for 12 AF patients and discussed simulation results from the perspective of Virchow's triad. The simulation results indicate the effectiveness of Virchow's triad in elucidating the thrombosis mechanism within the LAA. The LAA is more prone to thrombosis than the other region of LA, because of the lower blood flow velocity and significantly higher endothelial cell activation potential values there, which indicates a higher risk of blood stasis and endothelial injury, respectively. Furthermore, a comprehensive score is proposed to assess the performance of Virchow's triad in the LAA. The morphology of LA has a significant influence on the performance of the three factors in Virchow's triad. Hence, for a quickly assessment of LAA thrombosis risk in AF patients through the lens of Virchow's triad, we need a more refined shape scoring system that can better reflect patient-specific morphological features of the entire LA.

Association Between Pentoxifylline Use and Diabetic Retinopathy in Patients with Type 2 Diabetes Mellitus and Chronic Kidney Disease: A Multi-Institutional Cohort Study

BackgroundPentoxifylline is administrated to improve the hemodynamics of patients with chronic kidney disease (CKD). Despite the improvement of capillary blood flow velocity in retina after pentoxifylline use, no evidence has been provided to prove the protective effect for diabetic retinopathy (DR). Therefore, this study aimed to assess the risk of DR in pentoxifylline users with CKD and diabetes mellitus (DM). Material and methodsIn this retrospective cohort study, Chang Gung Research Database, which includes the data of patients with CKD and DM from 2003 to 2019, was used. Each calendar year was divided into 4 data units with 3 months each for every patient and every year during the follow-up. The ocular outcomes were new-onset DR, DR-related complications, and vitreoretinal interventions. ResultsTotal 56,439 patients without preexisting DR and 5,039 patients with preexisting DR were included in this study. Exposure to pentoxifylline was associated with elevated risk of new-onset DR (adjusted hazard ratio = 1.24, 95% confidence interval = 1.13–1.36) in patients without preexisting DR. Additionally, exposure to pentoxifylline was associated with elevated risk of DR-related complications and vitreoretinal interventions in patients with or without preexisting DR. ConclusionsExposure to pentoxifylline is associated with elevated risk of DR, regardless of whether patients have preexisting DR.

Multimodal Imaging, Including Laser Speckle Flowgraphy: A Case of Retinal Metastasis.

Intraocular metastases of systemic cancer are most frequently located in the choroid, followed by the iris and ciliary body, while retinal metastases are extremely rare. Here we present a case of retinal metastasis and analyze multimodal imaging. A 66-year-old woman with a medical history of breast cancer 5 years earlier was referred to our Department struggling with blurry vision in her right eye. At initial examination, her best-corrected visual acuity (BCVA) was 1.0 oculus dexter (OD). Fundus examination revealed a yellowish elevated lesion with irregular surface, measuring 2 papillary diameters, along with serous retinal detachment (SRD) on the temporal side of the optic disc. Optical coherence tomography showed SRD with an isointense nodule extending across all retinal layers. Fluorescein angiography showed hyperfluorescence and vigorous fluorescence leakage inside the tumor in the early and late phases, respectively. Indocyanine green angiography depicted feeder and drainage vessels within the mass. Laser speckle flowgraphy (LSFG) showed a cold signal inside the tumor. Based on these clinical findings, the mass was diagnosed as a retinal metastasis. Eight days after the initial visit, the patient underwent external beam radiation to the right eye. One month after the initial diagnosis, her BCVA was 0.7 OD, the tumor was localized, and SRD had decreased. LSFG indicated vascular remodeling with marginally warmer signals in the tumor. LSFG of the retinal metastasis showed a cold signal, suggesting low tumor blood flow velocity and that the tumor may have grown slowly. LSFG findings are likely to play a supportive role in clinical diagnosis and contribute to better understanding of pathogenesis in juxtapapillary tumors.

Peculiarities of angiospasm and ischemic complications in ruptures of cerebral arterial aneurysms against the background of occlusive-stenotic lesions of cerebral arteries

Objective – to determine the effect of occlusive-stenotic lesions of cerebral arteries on angiospasm and ischemic complications in patients with ruptured arterial aneurysms against the background of occlusive-stenotic lesions of cerebral arteries. Materials and methods. A retrospective study of the medical histories of 1,147 patients with cerebral artery aneurysms from 2006 to 2022 was conducted. 63 patients were included in the study group because they met the following criteria: surgical treatment; rupture of saccular aneurysms (SAs); the presence of occlusive-stenotic lesions was proven using instrumental examination methods. Patients of the control group had to meet the following criteria: surgical treatment; rupture of SAs; the absence of occlusive-stenotic lesions was proven by means of instrumental examination methods; the gender and age distribution had to match the study group. Of the 126 patients included in this study, there were 76 men (60.32%) and 50 women (39.68%). The age of the patients varied from 31 to 77 years. The average age of patients- 55.9±0.76 years; men – 54.3±0.94 years, women – 58.3±1.19 years. Results. A percentage predominance of patients with high cerebral blood flow velocity (&gt;200 cm/s, which is equal to the velocity with severe grade III vasospasm of the cerebral arteries) in the study group (32.56%) compared with the control group (24.24%) was revealed. Conclusions. The predominance of men among patients of the study group (60.32%) was established. The average age of men with occlusive-stenotic lesions was younger than that of women (men – 54.3±0.94 years, women – 58.3±1.19 years). The difference in age is the largest in the 2nd subgroup of the study group where the severity of stenosis is 50-75% (men - 48.3 years; women - 62 years). Ruptures of arterial aneurysms of the middle cerebral artery occur more often in the presence of stenoses (study group - 25.4%, control group - 12.7%). The neurological status of patients with a hemorrhagic stroke, as a result of the rupture of an arterial aneurysm, is significantly aggravated by occlusive-stenotic lesions due to the occurrence of chronic brain ischemia. The worst prognosis for life and health was in men with a ruptured arterial aneurysm against the background of a 50-75% stenotic lesion and severe vasospasm of the cerebral arteries.

Modeling of rabbit femoral artery occlusion by high-intensity focused ultrasound

One of the effective methods of artery and vein occlusion used in experimental studies and in clinical practice for certain diseases is local exposure of vessels to high-intensity focused ultrasound (HIFU). The wide use of this method in our country is limited by the lack of appropriate domestic equipment. At the Peter the Great St. Petersburg Polytechnic University, in the Laboratory of Ultrasound Technologies of the Center for Advanced Research, a stand for HIFU effects on various biological objects has been developed. There is no experience in using this device in angiology yet. The purpose of our research was to study the possibility of using Medusa 008, a high-tech mobile medical device designed for ultrasound diagnosis and personalized HIFU therapy, to model vascular occlusion and stop blood flow during irradiation. Materials and methods. The object of the study is the femoral artery of a rabbit. The source of HIFU is Medusa 008, the high-tech mobile medical device designed for ultrasound diagnostics and personalized HIFU-therapy with radiation frequency of 2 MHz (prototype). The following irradiation modes were used in the research: irradiation duration - 50 ms, pause between exposures – 10 ms, number of pulses – 20, 30, 40. The following energy values corresponded to these modes: 58 J, 87 J, 116 J. Irradiation of the femoral artery of an anesthetized rabbit was performed percutaneously. We used ultrasound to visualize the arteries and measure the blood flow velocity. According to ultrasound data, after HIFU irradiation, blood flow in the artery stopped. The factor contributing to arterial occlusion is the cessation of blood flow during irradiation. A histological examination of the area of the irradiated artery revealed structural changes in all layers of the vascular wall. Results. HIFU irradiation with intensity of 87 and 116 J has a significant dose-dependent destructive effect on the muscular arterial wall. The more intense damaging irradiation (116 J) causes smooth muscle cell necrosis. The time of direct influence on the vessel wall structures did not exceed 3 sec. During the experiment, we found that HIFU in the used modes causes temperature increase up to 45–60 оC, which is enough for thermal damage of cells in the irradiation zone. Conclusion. Thus, as a result of the above experiments, it was shown that Medusa 008, the high-tech mobile medical device designed for ultrasound diagnostics and personalized HIFU-therapy can be used to simulate vascular occlusion.

Diagnostic value of transcranial doppler to predict delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage

BackgroundTranscranial Doppler (TCD) is a technique to assess blood flow velocity in the cerebral arteries. TCD is frequently used to monitor aneurysmal subarachnoid hemorrhage (aSAH) patients. This study compares TCD-criteria for vasospasm and its association with Delayed Cerebral Ischemia (DCI). An overall score based on flow velocities of various intracranial arteries was developed and evaluated.MethodsA retrospective diagnostic accuracy study was conducted between 1998 and 2017 with 621 patients included. Mean flow velocity (MFV) of the cerebral artery was measured between 2–5 days and between 6–9 days after ictus. Cutoff values from the literature, new cutoff values, and a new composite score (Combined Severity Score) were used to predict DCI. Sensitivity, specificity, and area under the curve (AUC) were determined, and logistic regression analysis was performed.ResultsThe Combined Severity Score showed an AUC 0.64 (95%CI 0.56-.71) at days 2–5, with sensitivity 0.53 and specificity 0.74. The Combined Severity Score had an adjusted Odds Ratio of 3.41 (95CI 1.86–6.32) for DCI. MCA-measurements yielded the highest AUC to detect DCI at day 2–5: AUC 0.65 (95%CI 0.58–0.73). Optimal cutoff MFV of 83 cm/s for MCA resulted in sensitivity 0.73 and specificity 0.50 at days 2–5.ConclusionTCD-monitoring of aSAH patients may be a valuable strategy for DCI risk stratification. Lower cutoff values can be used in the early phase after the ictus (day 2–5) than are commonly used now. The Combined Severity Score incorporating all major cerebral arteries may provide a meaningful contribution to interpreting TCD measurements.

Коагуляційні характеристики пуповинної крові при затримці росту плода

Fetal growth restriction (FGR) is a common complication of pregnancy associated with severe perinatal consequences, a significant part of which is hemorrhagic and thrombotic disorders. Fetuses with FGR have thrombocytopenia, platelet dysfunction, and distortion of standard coagulation tests. There are few studies of the coagulation system in such newborns in vivo in the literature. Аim - to assess the relationship between the Doppler criteria of FGR and the kinetic manifestations of umbilical artery blood coagulation and fibrinolysis according to rotational thromboelastometry. Materials and methods. Prenatal Doppler parameters and postpartum kinetic parameters of blood coagulation and fibrinolysis in 118 newborns from singleton births were analyzed: the Group I - 67 newborns with FGR; the Group II - 51 full-term newborns from healthy mothers. Results. A significant decrease in the uterine and umbilical arteries resistance and blood flow velocity in FGR cases has been established. Thromboelastometric tests in the umbilical cord blood of the Group I newborns showed faster than in the Group II the blood clot formation, its greater firmness and delayed fibrinolysis. Comparison using rank correlation showed a relationship of average strength between the velocity of blood flow in the umbilical cord arteries and the blood clot firmness. Correlation between blood flow velocity in the midbrain and uterine arteries and coagulation indicators are weak. Conclusions. Reduced resistance index in the middle cerebral artery of fetuses with FGR indicates reduced resistance in these vessels, which should be regarded as signs of decentralization of fetal circulation. The blood of newborns with FGR is dominated by the processes of increased coagulation and slowing down of fibrinolysis, regardless of the date of birth. An increase in the pulsation index in the umbilical cord arteries during pregnancy can be considered a prognostically favorable hemodynamic characteristic in FGR. The study was carried out in accordance with the principles of the Helsinki Declaration. The research protocol was approved by the Local Ethics Committee of the institution mentioned in the work. The authors declare that there is no conflict of interest.

Assessment of hemodynamic parameters based on the results of ultrasound Dopplerography in different variants of the position of vessels in the area of bifurcation of the common carotid arteries

Introduction. Ultrasound imaging allows us to study the influence of topographic and anatomical variability of the main vessels of the neck on hemodynamic parameters in the area of bifurcation of the common carotid artery (CCA). Aim. To assess the significance of changes in hemodynamic parameters on the damage of the main arteries near the bifurcation of the common carotid artery in different variants of the mutual position of vessels according to the results of ultrasound Dopplerography. Materials and methods. 865 volunteers were examined using SonoAce R7 and Logiq F6. The results were summarized, systematized and processed in Microsoft Excel 2007 spreadsheets and subjected to statistical analysis. Among the participants, 5 main variants of the mutual position of the vessels were identified: A – typical; Б – the external carotid artery (ECA) is located ventrally; В – the lateral position of the external carotid artery; Г – divergence or intersection of the carotid arteries near bifurcation; Д – joint medial deviation of both carotid arteries. Results. A total of 1730 vascular complexes were evaluated. The smallest diameter of the external carotid arteries was observed in groups A and B – 3.10 mm. The largest value of the diameter of the internal carotid arteries (ICA) was in group D – 4.20 mm and in group B – 4.10 mm. The diameter of the common carotid arteries in groups A and B was 5.50 mm, in groups D and D – 5.60 mm, and in group B – 5.70 mm. The volume velocity of blood flow had higher values in group D. The lowest indicators of volumetric blood flow velocity were noted in group A, for common carotid and internal carotid arteries – in group G. Conclusions. The smallest average and median diameter of the external carotid arteries was observed in types A and B. The highest median diameter of the internal carotid arteries was in group D (4.20 mm). The median value of the diameter of the common carotid arteries was the maximum in group B (5.70 mm). The presented observation results demonstrate the effect of anatomical variation on the morphometric and functional characteristics of the vascular bed, reflecting the change in the calculated volumetric velocity of blood flow.

Influence of the zoledronic acid accumulative effect on the microcirculation state in the rat periodontium

Objective. To determine the character of changes in the reactivity of rat periodontal microvessels depending on the multiplicity of zoledronic acid administration. Material and Methods. Wistar rats (n = 36) were divided into groups of 9 rats each. In group No. 1 (control), rats were injected with 0.9% sterile sodium chloride solution once a week for 3 weeks; in group No. 2, rats were injected once with zoledronic acid (ZA) once a week; in group No. 3, rats were injected intravenously with ZA once a week for 3 weeks; in group No. 4, rats were injected with ZA once a week for 6 weeks. ZA was administered at a dose of 0.18 mg/kg in 0.9% sterile sodium chloride solution in the volume of 1 ml/kg. The microcirculation parameters in the periodontium were determined before ZA administration and on the 3rd day after administration by laser Doppler flowmetry (LDF) and ultrasound high-frequency dopplerography (UHFD) methods. Periodontal vascular reactivity was determined using acetylcholine assay. Results. After ZA administration, the indices of microcirculatory vascular reactivity decreased in rats of groups No. 3 and No. 4 in comparison with the results obtained before ZA administration: at ultrasound examination the maximum increase of blood flow velocity was noted at the 2nd minute and amounted to 133±8,5, 112±7,8 %, respectively. In rats of group No. 2, the increase in blood flow velocity corresponded to the value of the control group. In LDF study, the maximal blood flow rates were lower than in the control group in rats administered the drug for 3 and 6 weeks, respectively. Conclusion. Zoledronic acid dose-dependently causes impaired vascular responsiveness and leads to a decrease in endothelium-dependent vasodilation.

Value of fetal echocardiographic examination in pregnancies complicated by preterm premature rupture of membranes.

Cardiopulmonary and infectious complications are more common in preterm newborns after preterm premature rupture of membranes (pPROM). Fetal echocardiography may be helpful in predicting neonatal condition. Our aim was to assess the cardiovascular changes in fetuses from pregnancies complicated by pPROM and possible utility in predicting the intrauterine or neonatal infection, and neonatal heart failure (HF). It was a prospective study enrolling 46 women with singleton pregnancies complicated by pPROM between 18+0 and 33+6 weeks of gestation and followed until delivery. 46 women with uncomplicated pregnancies served as a control group. Fetal echocardiographic examinations with the assessment of cardiac structure and function (including pulmonary circulation) were performed in all patients. Mean gestational age of pPROM patients was 26 weeks. Parameters suggesting impaired cardiac function in fetuses from pPROM were: higher right ventricle Tei index (0.48 vs. 0.42 p<0.001), lower blood flow velocity in Ao z-score (0.14 vs. 0.84 p=0.005), lower cardiovascular profile score (CVPS), higher rate of tricuspid regurgitation (18.2 % vs. 4.4 % p=0.04) and pericardial effusion (32.6 vs. 0 %). Intrauterine infection was diagnosed in 18 patients (39 %). 4 (8.7 %) newborns met the criteria of early onset sepsis (EOS). HF was diagnosed in 9 newborns. In fetal echocardiographic examination HF group had shorter mitral valve inflow time and higher left ventricle Tei index (0.58 vs. 0.49 p=0.007). Worse cardiac function was observed in fetuses from pPROM compared to fetuses from uncomplicated pregnancies.

Medical-Surgical Implications of Branching Variation of Human Aortic Arch Known as Bovine Aortic Arch (BAA).

(1) Background: The aortic arch (AA) branching model is challenging, considering the multiple anatomical variations documented in existing research. The bovine aortic arch (BAA) is the most prevalent anatomical variation among these. This variant of AA branching has long been considered a nonsymptomatic malformation, having been discovered incidentally during imaging investigations for other causes. However, more recent studies have demonstrated that BAA shows a frequent association with coarctation of the aorta (CoA), thoracic aortic disease (TAD), and stroke. At the same time, given the current context of increasing activity in the fields of interventional and surgical procedures in the aorta and its branches, it is very important to know the medical-surgical implications of this anatomical variant. (2) Methods: We conducted a comprehensive review using PubMed and Embase, focusing specifically on randomized trials and cohort analyses that examined the medical-surgical implications of BAA. We assessed information related to studied groups, medical procedures, and study outcomes. Initially, we identified 8454 studies, and after rigorous evaluation, we narrowed down our review to 25 articles. (3) Discussions: The intervention consisted of assessing the risks associated with BAA through different imaging investigation methods such as computer tomographic angiography (CTA), magnetic resonance imaging (MRI), or ultrasonography (US). The following results were evaluated: the prevalence of the BAA, the importance of imaging investigations in establishing the diagnosis and the therapeutic management and monitoring the evolution of patients with the BAA, the association of the BAA with CoA, TAD, and stroke, and the potential risks of interventional treatment in patients with the BAA. (4) Conclusions: The prevalence of the BAA differs both between different ethnic groups and between genders. Advanced imaging methods such as CTA and 4D flow MRI allow detailed descriptions of supra-aortic vascular anatomy and information about blood flow velocities, direction, and turbulence in the AA. US remains an easy and valuable imaging investigation, with the potential to detect and correctly diagnose the BAA and its hemodynamic implications. Anatomical variations in the AA are associated with increased rates of TAD, CoA, and stroke, necessitating early diagnosis and increased supervision of patients with such incidentally observed abnormalities. In addition, there is a need to further develop and refine the surgical techniques used and personalize them to the individual characteristics of patients with the BAA.

Unveiling thermal and hemodynamic effects of aneurysm on abdominal aorta using power law model and finite element analysis

The objective of this study is to find causes of aortic diseases and investigating the ways for better treatment. The governing system of equations has been demonstrated to account for characteristics of blood. The governing system of equation has been solved using the finite element method with appropriate boundary conditions. We analyzed into the relationship between flow characteristics via the aneurysmal abdominal aorta and the aneurysm height, aneurysm length, and non-Newtonian behavior. It investigates how thermal and hemodynamics effects change across the abdominal aortic aneurysm. The velocity, pressure, and temperature surface plots of the results are displayed. There have also been graphic displays of line graphs of axial velocity, radial velocity, axial pressure, radial pressure, axial temperature and radial temperature across the aneurysm. The blood flow simulations obtained results show that increasing blood temperature, pressure and intake velocity all contribute to an increase in viscosity. The results indicate that while the temperature varies little to not at all, the blood flow pressure decrease and velocity significantly vary.

Peak detection in intracranial pressure signal waveforms: a comparative study

BackgroundThe monitoring and analysis of quasi-periodic biological signals such as electrocardiography (ECG), intracranial pressure (ICP), and cerebral blood flow velocity (CBFV) waveforms plays an important role in the early detection of adverse patient events and contributes to improved care management in the intensive care unit (ICU). This work quantitatively evaluates existing computational frameworks for automatically extracting peaks within ICP waveforms.MethodsPeak detection techniques based on state-of-the-art machine learning models were evaluated in terms of robustness to varying noise levels. The evaluation was performed on a dataset of ICP signals assembled from 700 h of monitoring from 64 neurosurgical patients. The groundtruth of the peak locations was established manually on a subset of 13, 611 pulses. Additional evaluation was performed using a simulated dataset of ICP with controlled temporal dynamics and noise.ResultsThe quantitative analysis of peak detection algorithms applied to individual waveforms indicates that most techniques provide acceptable accuracy with a mean absolute error (MAE) ≤10\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\le 10$$\\end{document} ms without noise. In the presence of a higher noise level, however, only kernel spectral regression and random forest remain below that error threshold while the performance of other techniques deteriorates. Our experiments also demonstrated that tracking methods such as Bayesian inference and long short-term memory (LSTM) can be applied continuously and provide additional robustness in situations where single pulse analysis methods fail, such as missing data.ConclusionWhile machine learning-based peak detection methods require manually labeled data for training, these models outperform conventional signal processing ones based on handcrafted rules and should be considered for peak detection in modern frameworks. In particular, peak tracking methods that incorporate temporal information between successive periods of the signals have demonstrated in our experiments to provide more robustness to noise and temporary artifacts that commonly arise as part of the monitoring setup in the clinical setting.