Artery Blood Flow Research Articles

Mathematical formulation and computation of the dynamics of blood flow, heat and mass transfer during MRI scanning

Computational modeling of arterial blood flow, heat and mass transfer during MRI scanning is studied. The flow is assumed to be unsteady, in-compressible, and asymmetric. Mathematical formulation considers the presence of stenosis, joule heating viscous dissipation and chemical reaction. The explicit finite difference scheme is used to numerically solve the model equations. The MATLAB software was used to plot the graphical results. The study reveals that, during MRI scanning, both radial and axial velocities diminish with increase in the strength of magnetic fields. Besides, the study found that, Eckert number and Hartman number enhance the blood’s temperature and the same, diminishes with increase in Prandtl and Reynolds numbers. Concentration profile is observed to decline with increase in chemical reaction parameter, Schmidt number and Reynolds number. Soret number on the other hand, is observed to positively influence the concentration.

Hemorrhage at high altitude: impact of sustained hypobaric hypoxia on cerebral blood flow, tissue oxygenation, and tolerance to simulated hemorrhage in humans.

With ascent to high altitude (HA), compensatory increases in cerebral blood flow and oxygen delivery must occur to preserve cerebral metabolism and consciousness. We hypothesized that this compensation in cerebral blood flow and oxygen delivery preserves tolerance to simulated hemorrhage (via lower body negative pressure, LBNP), such that tolerance is similar during sustained exposure to HA vs. low altitude (LA). Healthy humans (4F/4M) participated in LBNP protocols to presyncope at LA (1130m) and 5-7days following ascent to HA (3800m). Internal carotid artery (ICA) blood flow, cerebral delivery of oxygen (CDO2) through the ICA, and cerebral tissue oxygen saturation (ScO2) were determined. LBNP tolerance was similar between conditions (LA: 1276 ± 304s vs. HA: 1208 ± 306s; P = 0.58). Overall, ICA blood flow and CDO2 were elevated at HA vs. LA (P ≤ 0.01) and decreased with LBNP under both conditions (P < 0.0001), but there was no effect of altitude on ScO2 responses (P = 0.59). Thus, sustained exposure to hypobaric hypoxia did not negatively impact tolerance to simulated hemorrhage. These data demonstrate the robustness of compensatory physiological mechanisms that preserve human cerebral blood flow and oxygen delivery during sustained hypoxia, ensuring cerebral tissue metabolism and neuronal function is maintained.

The association between cerebral blood flow variations during on-pump coronary artery bypass grafting surgery and postoperative delirium.

Postoperative delirium (POD) has a major impact on patient recovery after cardiac surgery. Although its pathophysiology remains unclear, there could be a correlation between cerebral blood flow (CBF) variations during cardio-pulmonary bypass (CPB) and POD. Our study aimed to evaluate whether variations in on-pump CBF, compared to pre-anesthesia and pre-CPB values, are associated with POD following coronary artery bypass grafting (CABG) surgery. This prospective observational cohort study included 95 adult patients undergoing elective on-pump CABG surgery. Right middle cerebral artery blood flow velocity (MCAV) was assessed using Transcranial Doppler before anesthesia induction, before CPB and every fifteen minutes during CPB. Pre-anesthesia and pre-CPB values were chosen as baselines. Individual values, measured during CPB, were converted as percentage changes relative to these baselines and named as %MCAV0 and %MCAV1, respectively. POD was assessed using the Confusion Assessment Method for ICU (CAM-ICU) during the first 48 post-operative hours and with the 3-Minute Diagnostic Interview for Confusion Assessment Method (3D-CAM) on the fifth post-surgical day. Overall POD incidence was 17.9%. At 30minutes of CPB, %MCAV0 was higher in POD group than in no-POD group (p = .05). %MCAV0 at 45minutes of CPB was significantly higher in POD group (87 (±17) %) than in no-POD group (68 (±24) %), p = .04. %MCAV1 at 30 and 45minutes of CPB were higher in POD group than in no-POD group, at the limit of statistical significance. We found %MCAV1 > 100% in POD group, but not in no-POD group. Significant differences in %MCAV0 became evident after 30minutes of CPB, whereas differences in %MCAV1 at 45 minutes of CPB were at limit of statistical significance. In POD group %MCAV1 was higher than 100% at 30 and 45minutes of CPB, which is supposed to be a sign of cerebral hyperperfusion. Monitoring CBF during CPB could have prognostic value for POD.

The combination of preoperative celiac axis stenting and neoadjuvant chemotherapy in an elderly patient with pancreatic cancer: a case report

BackgroundCeliac axis stenosis (CAS) is frequently observed in patients undergoing pancreaticoduodenectomy (PD). This poses challenges because of the potential disruption of the hepatic arterial blood flow.Case presentationWe present the case of an 81-year-old woman diagnosed with pancreatic head cancer and severe CAS caused by calcification. The patient received neoadjuvant chemotherapy (NAC) and underwent preoperative endovascular stenting of the celiac axis to restore blood flow. After two cycles of NAC, subtotal stomach-preserving PD was performed. An intraoperative assessment of the hepatic arterial blood flow determined that it was well maintained. PD was performed using the standard technique; specialized techniques were not necessary. Importantly, no ischemic complications were encountered.ConclusionThis case report describes the successful combination of preoperative celiac axis stenting, NAC, and surgical intervention for the management of CAS in an elderly patient with pancreatic cancer. This approach offers a potential solution for maintaining the hepatic arterial blood flow in the presence of CAS without vascular reconstruction, particularly in elderly individuals.

Efficacy and safety of combining ginkgolide diterpene glucosamine injection with dual antibodies in elderly patients with acute ischemic stroke

Purpose: To investigate the clinical effects and safety of ginkgo biloba diterpene lactone glucosamine injection, combined with dual antibiotic therapy for acute ischemic stroke in elderly individuals within a hyper thrombolytic time window. &#x0D; Methods: 100 elderly patients with acute ischemic stroke at Changsha First Hospital, Changsha, China from March 2022 to March 2023 were randomly and equally assigned to study and control groups (50 patients each). Study group received aspirin and clopidogrel, while control group received ginkgo biloba diterpene lactone glucosamine injection along with dual antibodies. Clinical efficacy, National Institutes of Health Stroke Scale (NIHSS) score, Instrumental Activities of Daily Living (IADL) score, cerebral hemodynamics, and safety were compared between the two groups. &#x0D; Results: There was no significant difference in effective rate between the two groups (p &gt; 0.05). However, following treatment, study group showed superior NIHSS and IADL scores compared to control group, with greater statistical significance as the disease progressed. Doppler ultrasound revealed that study group had smaller Pulsatility index (PI) values and larger mean cerebral artery blood flow velocity (Vm), and systolic value (Vs) compared to control group (p &lt; 0.05). In study group, three adverse reactions were reported (gastrointestinal discomfort, abnormal liver/kidney function, and skin itching), whereas the control group experienced five adverse reactions (gastrointestinal discomfort, abnormal liver/kidney function, dizziness, and skin itching). &#x0D; Conclusion: The combination of Ginkgo biloba diterpene lactone glucosamine injection and dual antibodies in elderly individuals with acute ischemic stroke within a super thrombolytic time window enhances intracerebral blood flow levels, effectively promotes neurological recovery, improves daily living abilities, and safety. Further research is needed to elucidate the exact pathways involved.

Oral Vitamin C Supplementation and its Impact on Endothelial Function in Obstructive Sleep Apnea Patients

Background – Obstructive Sleep Apnea (OSA) is a prevalent condition associated with endothelial dysfunction, a precursor to cardiovascular disease. Passive Leg Movement (PLM) has emerged as a simple method to assess endothelial function. The role of oral vitamin C in improving endothelial function in OSA patients, however, has been underexplored. Materials and Methods This study recruited 26 male subjects, 13 with OSA and 13 healthy controls, aged 18-55 years. PLM was utilized to assess endothelial function by measuring femoral artery blood flow (FBF) and velocity (FBV) using Doppler ultrasound, pre- and post-administration of 1000mg of oral vitamin C. The intervention aimed to compare endothelial function responses between OSA patients and healthy controls, and to evaluate the impact of oral vitamin C on these responses. Results Baseline comparisons revealed a significant difference in FBF between OSA patients (76.6 ml/min) and healthy controls (162.1 ml/min, p &lt; 0.05), indicating endothelial dysfunction in OSA. Post-vitamin C intervention, the peak FBF responses in OSA patients showed no significant difference (Pre-vitamin C: 76.6 ml/min, Post-vitamin C: 79.9 ml/min, p &gt; 0.05), suggesting that oral vitamin C did not significantly improve endothelial function in OSA patients. Conclusion PLM effectively distinguished between healthy subjects and those with OSA through differences in FBF, confirming its utility as a diagnostic tool for endothelial dysfunction. However, oral vitamin C supplementation did not significantly enhance endothelial function in OSA patients, indicating the need for further research into alternative or adjunctive therapies.

Passive Leg Movement as a Diagnostic Tool for Distinguishing Healthy Individuals from Those with Obstructive Sleep Apnea

Background – Obstructive Sleep Apnea (OSA) is linked with endothelial dysfunction, posing a significant risk for cardiovascular diseases. The non-invasive assessment of endothelial function through passive leg movement (PLM) offers a novel diagnostic avenue. This study explores PLM's efficacy in differentiating between healthy individuals and those with OSA, alongside evaluating the impact of oral vitamin C on endothelial function within these groups. Materials and Methods: The study enrolled 26 male subjects, divided equally into healthy and OSA groups. PLM was performed using an isokinetic machine to assess femoral artery blood flow (FBF) and blood velocities (FBVs) via Doppler ultrasound. Subjects consumed 1000mg of oral vitamin C, with measurements repeated post-consumption. Data analysis involved repeated measures ANOVA to evaluate the diagnostic capability of PLM and the effect of vitamin C on FBF responses. Results: A significant difference in FBF was observed between OSA and healthy groups (healthy: 162.1 ml/min, OSA: 76.6 ml/min; p &lt; 0.05), confirming PLM's diagnostic potential. However, vitamin C administration did not significantly alter FBF responses in OSA patients (pre-vitamin C: 76.6 ml/min, post-vitamin C: 79.9 ml/min; p &gt; 0.05), challenging the anticipated benefits of oral vitamin C on endothelial function. Conclusion: PLM effectively distinguishes between healthy individuals and those with OSA, highlighting its diagnostic utility. Nonetheless, oral vitamin C did not improve endothelial dysfunction in OSA patients, suggesting the need for further research on alternative administration methods or dosages.

In vivo phenotypic vascular dysfunction extends beyond the aorta in a mouse model for fibrillin-1 (Fbn1) mutation

In individuals with Marfan Syndrome (MFS), fibrillin-1 gene (FBN1) mutations can lead to vascular wall weakening and dysfunction. The experimental mouse model of MFS (Fbn1C1041G/+) has been advantageous in investigating MFS-associated life-threatening aortic aneurysms. It is well established that the MFS mouse model exhibits an accelerated-aging phenotype in elastic organs like the aorta, lung, and skin. However, the impact of Fbn1 mutations on the in vivo function and structure of various artery types with the consideration of sex and age, has not been adequately explored in real-time and a clinically relevant context. In this study, we investigate if Fbn1 mutation contributes to sex-dependent alterations in central and cerebral vascular function similar to phenotypic changes associated with normal aging in healthy control mice. In vivo ultrasound imaging of central and cerebral vasculature was performed in 6-month-old male and female MFS and C57BL/6 mice and sex-matched 12-month-old (middle-aged) healthy control mice. Our findings confirm aortic enlargement (aneurysm) and wall stiffness in MFS mice, but with exacerbation in male diameters. Coronary artery blood flow velocity (BFV) in diastole was not different but left pulmonary artery BFV was decreased in MFS and 12-month-old control mice regardless of sex. At 6 months of age, MFS male mice show decreased posterior cerebral artery BFV as compared to age-matched control males, with no difference observed between female cohorts. Reduced mitral valve early-filling velocities were indicated in MFS mice regardless of sex. Male MFS mice also demonstrated left ventricular hypertrophy. Overall, these results underscore the significance of biological sex in vascular function and structure in MFS mice, while highlighting a trend of pre-mature vascular aging phenotype in MFS mice that is comparable to phenotypes observed in older healthy controls. Furthermore, this research is a vital step in understanding MFS's broader implications and sets the stage for more in-depth future analyses, while providing data-driven preclinical justification for re-evaluating diagnostic approaches and therapeutic efficacy.

The effect of an endovascular Heaney maneuver to achieve total hepatic isolation on survival, hemodynamic stability, retrohepatic bleeding, and collateral flow in a porcine model

PurposeCombining resuscitative endovascular balloon occlusion of the aorta (REBOA) and the inferior vena cava (REBOVC) with open surgery is a new hybrid approach for treating retrohepatic vena caval injuries. We compared endovascular total hepatic isolation with supraceliac REBOA ± suprahepatic REBOVC and no occlusion in experimental retrohepatic vena cava bleeding regarding survival, bleeding volume, hemodynamic stability, and arterial collateral blood flow.MethodsTwenty-five anesthetized pigs (n = 6–7/group) were randomized to REBOA; REBOA + REBOVC; REBOA + infra and suprahepatic REBOVC + portal vein occlusion (endovascular Heaney maneuver, four-balloon-occlusion, 4BO) or no occlusion. After balloon inflation, free bleeding was initiated from an open sheath in the retrohepatic vena cava. Bleeding volume, right internal thoracic artery (RITA) blood flow, hemodynamics, and arterial blood variables were measured until death or up to 90 min.ResultsThe REBOA group had a longer median survival time (63 min) compared with the 4BO (24 min, P = 0.02) and no occlusion (30 min, P = 0.02) groups, not versus the REBOA + REBOVC group (49 min, P > 0.05). The first 15 min accumulated bleeding was comparable in all groups (P > 0.05); Thereafter, bleeding volume was higher in the REBOA group versus the 4BO group (P < 0.05), not versus the other groups. RITA blood flow and MAP were higher in the REBOA group versus the other groups after 10 min of bleeding (P < 0.05).ConclusionsEndovascular Heaney maneuver was not beneficial for survival or hemodynamic stability in this porcine model, whereas supraceliac REBOA was. Anatomical differences in thoracoabdominal collaterals between pigs and humans must be considered when interpreting these results.

Study of the mechanism of action of sand therapy on atherosclerosis based on the two-phase flow-Casson model.

Sand therapy is a non-pharmacological physiotherapy method that uses the natural environment and resources of Xinjiang to treat through the heat transfer and magnetic effects of sand. Employing the two-phase flow-Casson blood flow model, we investigate the mechanism of atherosclerosis prevention via sand therapy, offering a biomechanical theoretical rationale for the prevention of atherosclerosis through sand therapy via the prism of computational fluid dynamics (CFD). Sand therapy experiments were conducted to obtain popliteal artery blood flow velocity, and blood was considered as a two-phase flow composed of plasma and red blood cells, and CFD method was applied to analyze the hemodynamic effects of Casson's blood viscosity model before and after sand therapy. (1) The blood flow velocity increased by 0.24 m/s and 0.04 m/s at peak systolic and diastolic phases, respectively, after sand therapy; the axial velocity of blood vessels increased by 28.56% after sand therapy. (2) The average red blood cell viscosity decreased by 0.00014 Pa ⋅ s after sand therapy. (3) The low wall shear stress increased by 1.09Pa and the high wall shear stress reached 41.47Pa after sand therapy. (4) The time-averaged wall shear stress, shear oscillation index and relative retention time were reduced after sand therapy. The increase of blood flow velocity after sand therapy can reduce the excessive deposition of cholesterol and other substances, the decrease of erythrocyte viscosity is beneficial to the migration of erythrocytes to the vascular center, the increase of low wall shear stress has a positive effect on the prevention of atherosclerosis, and the decrease of time-averaged wall shear stress, shear oscillation index and relative retention time can reduce the occurrence of thrombosis.

Diurnal variation of cerebral blood flow in healthy humans under normal entrained conditions.

The presence of a circadian cycle of cerebral blood flow may have implications for the occurrence of daily variations in cerebrovascular events in humans, but how cerebral blood flow varies throughout the day and its mechanism are still unclear. The study aimed to explore the diurnal variation of cerebral blood flow in healthy humans and its possible mechanisms. Arterial spin labelling images were collected at six time-points (09:00 hours, 13:00 hours, 17:00 hours, 21:00 hours, 01:00 hours, 05:00 hours) from 18 healthy participants (22-39 years old; eight females) to analyse diurnal variations in cerebral blood flow. Resting heart rate and blood pressure at six time-points and blood indicators (20-hydroxyeicosatetraenoic acid, epoxyeicosatrienoic acids, prostaglandin E2, noradrenaline and nitric oxide) related to cerebral vascular tone at two time-points (09:00 hours and 21:00 hours) were collected to analyse possible influences on diurnal variations in cerebral blood flow. From 21:00 hours to 05:00 hours, parietal cortical relative cerebral blood flow tended to increase, while frontal cortical and cerebellar relative cerebral blood flow tended to decrease. There was a time-dependent negative correlation between parietal cortical relative cerebral blood flow and resting heart rate, whereas there was a time-dependent positive correlation between cerebellar relative cerebral blood flow and resting heart rate. The change of parietal cortical relative cerebral blood flow was positively correlated with the change of nitric oxide. There was also a time-dependent positive correlation between mean arterial pressure and mean whole-brain cerebral blood flow. The findings indicated that parietal cortical relative cerebral blood flow and frontal cortical/cerebellar relative cerebral blood flow showed roughly opposite trends throughout the day. The diurnal variations in relative cerebral blood flow were regional-specific. Diurnal variation of nitric oxide and neurogenic regulation may be potential mechanisms for diurnal variation in regional relative cerebral blood flow.

Conventional and contrast-enhanced ultrasound in the differential diagnosis of recurrent dermatofibrosarcoma protuberans and postoperative scar

BackgroundDermatofibrosarcoma protuberans (DFSP) has a high recurrence rate after resection. Because of the lack of specific manifestations, recurrent DFSP is easily misdiagnosed as post-resection scar. A few series have reported ultrasound findings of recurrent DFSP; moreover, the usefulness of contrast-enhanced ultrasound in differentiating recurrent DFSP has not been studied.ObjectiveWe investigated conventional and contrast-enhanced ultrasound in the differential diagnosis of recurrent DFSP and post-resection scar.MethodsWe retrospectively evaluated the findings of conventional and contrast-enhanced ultrasound in 34 cases of recurrent DFSP and 38 postoperative scars examined between January 2018 and December 2022.ResultsThe depth and vascular density of recurrent DFSP were greater than those of postoperative scars (P < 0.05). On gray-scale ultrasound, recurrent DFSP lesions were more commonly irregular, heterogeneous, and hypoechoic, with finger-like projections and ill-defined borders. Postoperative scar was more likely to appear as hypoechoic and homogeneous with well-defined borders (P < 0.05). On color Doppler ultrasound, recurrent DFSP was more likely to feature rich arterial and venous blood flow, and postoperative scar was more likely to display poor blood flow (P < 0.05). On contrast-enhanced ultrasound, recurrent DFSP was more likely to feature heterogeneous hyper-enhancement, and postoperative scar was more likely to display homogeneous iso-enhancement (P < 0.05). Recurrent DFSP presented a higher peak and sharpness than postoperative scar (P < 0.05).ConclusionConventional and contrast-enhanced ultrasound produced distinct features of recurrent DFSP and post-resection scar, which could improve the accuracy of differential diagnosis.

Immediate Effect of Electro-acupuncture on Endometrial Blood Flow in Patients with Recurrent Implantation Failure: A Randomized Controlled Trial.

To investigate the immediate effects of electro-acupuncture (EA) on endometrial blood flow among recurrent implantation failure (RIF) patients. Eighty RIF patients, enrolled from March 2022 to December 2022, were randomly allocated into either the EA group (40 cases) or the waiting-list (WL) group (40 cases) by using a random number table. The EA group underwent acupuncture at points of Shenting (GV 24), Baihui (GV 4), Benshen (GB 13), bilateral Zigong (EX-CA 1), Huangshu (KI 16), Sanyinjiao (SP 6) and Xuehai (SP10), and electric acupuncture apparatus was connected to EX-CA 1, KI 16, SP 6, and SP 10 with disperse-dense waves at 4/20 Hz frequencies for 30 min after transvaginal ultrasound, while the WL group received no intervention. The primary outcome measured was the endometrial volume blood flow. The secondary outcomes included the bilateral uterine artery index, endometrial volume, endometrial blood flow type, vascular distribution index (VIMV) for endometrial and ovary, clinical pregnancy rate, and embryo implantation rate. In the EA group, there was a notable decrease in the bilateral pulsatility index and a significant improvement in the endometrial blood flow type post-EA (P<0.05). Both the endometrial blood flow type and VIMV for the endometrium and right ovary were markedly higher in the EA group compared to the WL group post-treatment (P<0.05). Conversely, no significant disparities were observed in vascular index, flow index, vascular blood flow index, uterine arterial blood flow indices, endometrial volume, clinical pregnancy rate and embryo implantation rate between the two groups after treatment (P>0.05). Besides, no adverse events related to EA were observed. EA can promptly ameliorate VIMV for the endometrial and right ovary, and endometrial blood flow type. Future randomized controlled trials are warranted to investigate the long-term effects of EA on blood flow of RIF patients and its implications for pregnancy outcomes. (Trial registration No. ChiCTR2200057377).

Effect of use of exercise associated with ischemia and hyperemia on the systolic blood velocity of the superficial femoral artery (SFA) And develop some physical abilities of the lower limbs of basketball players

&#x0D; Exercises associated with ischemia – Hyperemia considered A modern technique in the field of sports training has been used very limited Because The results of previous studies on the interpretation of the positive and negative impact of this method vary The need for this study to identify the effect of the use of exercise associated with ischemia - Hyperemia on the systolic blood flow of the superficial femoral artery (SFA) And develop some physical abilities of the lower limbs of basketball players The objectives of the study were to identify the effect of the use of exercise associated with ischemia – Hyperemia on the systolic blood velocity of the superficial femoral artery (SFA) The hypotheses of the study there is a statistically significant relationship between the exercises associated with ischemia – Hyperemia and the systolic blood flow velocity of the superficial femoral artery (SFA) The sample consisted of ten basketball players for the Mustansiriya University team. The second section included the research methodology and its field procedures. The researcher used the instruments and tools required to accomplish the study, including the color Doppler device to measure the blood speed of the lower limb arteries (SFA). The program of work was prepared using the accompanying exercises of ischemia – Hyperemia and statistical treatments were carried out using SPSS program. The researcher reached several conclusions after presenting and analyzing the results, including the effect of the exercises associated with ischemia – Hyperemia on the speed of blood flow in the lower arteries of the lower arteries (SFA) and positively during the peak of systolic blood There is a direct correlation between the exercises associated with ischemia – Hyperemia and the speed of muscle re-activation of the muscles working in the lower limbs And develop some physical abilities of the lower limbs&#x0D; &#x0D;

Interactions between elementary waves and weak discontinuity in two-layer blood flow through artery

Blood flow through arterial circulation can be characterized by fluid transport in flexible tubes and modeled mathematically using the conservation of mass and momentum. A one-dimensional model for two-layer blood flow with different blood velocities and the same constant density in each layer derived from the Euler equations of gas dynamics by taking the vertical average across each layer. This work presents interactions of elementary waves with a weak discontinuity for the quasilinear 3 × 3 system of conservation laws governing the two-layer blood flow in arteries. Exploiting elementary waves as a single-parameter curve, we study the Riemann solution uniquely and consequently establish the condition on initial data for the existence of a solution to the Riemann problem. Furthermore, we discuss the evolution of weak discontinuity waves and subsequently derive their amplitudes; in what follows, we investigate the interactions of weak discontinuity with contact discontinuity and shocks. Finally, a series of numerical tests have been performed to understand the impact of shock strength and the initial data on the amplitudes of reflected and transmitted waves and the jumps in shock acceleration.

The Improvement in Exercise Performance during Reduced Muscle Mass Exercise is Associated with an Increase in Femoral Blood Flow in Older and Younger Endurance-Trained Athletes.

This study investigated whether the improved performance observed with maximal self-paced single-leg (SL), compared with double-leg (DL) cycling, is associated with enhanced femoral blood flow and/or altered tissue oxygenation. The hyperaemic response to exercise was assessed in younger and older athletes. Power output was measured in 12 older (65 ± 4 y) and 12 younger (35 ± 5 y) endurance-trained individuals performing 2 x 3 min maximal self-paced exercise using SL and DL cycling. Blood flow (BF) in the femoral artery was assessed using Doppler ultrasound and muscle oxygenation was measured using near-infrared spectroscopy on the vastus lateralis. SL cycling elicited a greater power output (295 ± 83 vs 265 ± 70 W, P < 0.001) and peak femoral BF (1749.1 ± 533.3 vs 1329.7 ± 391.7 ml/min, P < 0.001) compared with DL cycling. Older individuals had a lower peak BF in response to exercise (1355.4 ± 385.8 vs 1765.2 ± 559.6 ml/min, P = 0.019) compared with younger individuals. Peak BF in response to exercise was correlated with power output during SL (r = 0.655, P = 0.002) and DL (r = 0.666, P = 0.001) cycling. The greater exercise performance during SL compared with DL cycling may be partly explained by a greater hyperaemic response when reducing active muscle mass. Despite regular endurance training, older athletes had a lower femoral BF in response to maximal self-paced exercise compared with younger athletes.

The effect of acetylsalicylic acid intake on fetal adaptation in placental dysfunction

Placental dysfunction (PD) is one of the actual topics of research in the modern scientific world. Fetal growth retardation (FGR) is the leading clinical manifestation of chronic PD. Assessment of fetal growth is one of the key tasks in prenatal care. FGR is associated with an increased risk of perinatal morbidity and mortality, with long-term adverse outcomes for the child.Prenatal diagnosis of FGR is an important task for stillbirth prevention, up to 30% of cases of which are associated with this pathology or with a small-for-gestational-age fetus at the end of the III trimester.The objective: to study the influence of acetylsalicylic acid on the development of compensatory abilities of the fetus by PD.Materials and methods. 118 pregnancies with FGR and/or PD were analyzed. The women were divided into two groups: I group (67 persons) – patients with FGR and/or PD who used acetylsalicylic acid during pregnancy; II group (51 women) – pregnant women with FGR and/or PD who did not use acetylsalicylic acid during pregnancy. In all cases, the method of delivery was cesarean section due to fetal distress.Fetal distress was diagnosed using ultrasound examinations based on the following criteria: abnormal blood flow according to Doppler data (Volusun S10 ultrasound device), fetal biophysical profile indicators (Volusun S10 ultrasound device, Sonicaid Team fetal monitor) and cardiotocographic assessment of short-term variability (STV) fetal heart rate; STV &gt; 4.5 according to the Sonicaid Team fetal monitor. Exclusion criteria: multiple pregnancy, antenatally confirmed fetal malformations.Results. The use of acetylsalicylic acid through placental regulation allows to achieve a longer gestation period before the development of fetal distress. The average gestational age before the appearance of this pathology in 50.75% of patients of the I group (34 persons) was larger – 33–36 weeks. On the other hand, 54.9% of women (28 individuals) in the II group had fetal distress earlier – at 28–32 weeks of gestation (p&lt;0.05).Pathological blood flow in the umbilical artery or fetal biophysical profile &lt;4 points was determined in 83.6% of cases in the I group (56 pregnant women) and in 23.5% in the II group (12 women). In women who used acetylsalicylic acid (I group) acute fetal distress diagnosed by STV was detected in 11 (16.4%) cases. In women who did not use acetylsalicylic acid (II group), distress manifested itself sharply – due to acidosis – in 39 (76.5%) cases (p&lt;0.05).Conclusions. 1. In women who did not use acetylsalicylic acid, fetal distress manifested itself sharply – due to acidosis (STV&lt;4.5 was recorded in 39 (76.5%) patients of the II group, while in women who used acetylsalicylic acid – in 11 pregnant women of the I group (16.4%; p&lt;0.05). 2. Prophylactic use of acetylsalicylic acid allows to slow down the growth of placental dysfunction, which lets to the development of compensatory mechanisms and adaptation. 3. By use of acetylsalicylic acid the gestational period delivery closer to full term pregnancy. In women who used acetylsalicylic acid, most cases of fetal distress occurred at 33–36 weeks – 50.75%, while in the group that did not use acetylsalicylic acid most cases of fetal distress occurred at 28–32 weeks – in 54.9% (p&lt;0.05).

Cascaded Plane Wave Ultrasound for Blood Velocity Vector Imaging in the Carotid Artery.

Cascaded dual-polarity waves (CDWs) imaging increases the signal-to-noise ratio (SNR) by transmitting trains of pulses with different polarity order, which are combined via decoding afterward. This potentially enables velocity vector imaging (VVI) in more challenging SNR conditions. However, the motion of blood in between the trains will influence the decoding process. In this work, the use of CDW for blood VVI is evaluated for the first time. Dual-angle, plane wave (PW) ultrasound, CDW-coded, and noncoded conventional PW (cPW), was acquired using a 7.8 MHz linear array at a pulse repetition frequency (PRF) of 8 kHz. CDW-channel data were decoded prior to beamforming and cross correlation-based compound speckle tracking for VVI. Simulations of single scatterer motion show a high dependence of amplitude gain on the velocity magnitude and direction for CDW-coded transmissions. Both simulations and experiments of parabolic flow show increased SNRs for CDW imaging. As a result, CDW outperforms cPW VVI in low SNR conditions, based on both bias and standard deviation (SD). Quantitative linear regression and qualitative analyses of simulated realistic carotid artery blood flow show a similar performance of CDW and cPW for high SNR (14 dB) conditions. However, reducing the SNR to 6 dB, results in a root-mean-squared error 2.7× larger for cPW versus CDW, and an R2 of 0.4 versus 0.9. Initial in vivo evaluation of a healthy carotid artery shows increased SNR and more reliable velocity estimates for CDW versus cPW. In conclusion, this work demonstrates that CDW imaging facilitates improved VVI of deeper located carotid arteries.

The impact of multiple stenosis and aneurysms on arterial diseases: A cardiovascular study

The comparative effect of serial stenosis and aneurysms arteries on blood flow is examined to identify atherosclerotic diseases. The finite element approach has been used to solve the continuity, momentum, and Oldroyd-B partial differential equations to analyze the blood flow. Newtonian and non-Newtonian both cases are taken for the viscoelastic response of blood. In this study, the impact of multiple stenotic and aneurysmal arteries on blood flow have been studied to determine the severity of atherosclerosis diseases through the analysis of blood behavior. The novel aspect of the study is its assessment of the severity of atherosclerotic disorders for the occurrence of serial stenosis and aneurysm simultaneously in the blood vessel wall in each of the four cases. The maximum abnormal arterial blood flow effect is found for the presence of serial stenoses compared to aneurysms which refers to the severity of atherosclerosis. At the hub of stenosis, the blood velocity magnitude and wall shear stress (WSS) are higher, whereas the arterial wall normal gradient values are lower. For all cases, the contrary results are observed at the hub of the aneurysmal model. The blood flow has been affected significantly by the increases in Reynolds number for both models. The influence of stenotic and aneurysmal arteries on blood flow is graphically illustrated in terms of the velocity profile, pressure distribution, and WSS. Medical experts may use this study's findings to assess the severity of cardiovascular diseases.

Comparative Investigation of Color Doppler Ultrasonography Parameters of the Uterine Artery in Patients with Post-molar GTN and Patients Recovered from Molar Pregnancy and its Role in Predicting the Probability of Occurrence

Objectives: Hydatiform mole can progress to gestational trophoblastic neoplasia (GTN), and we are looking for non-invasive methods to predict it. Old age, higher serum BHCG levels, and expression of genes, such as VEGF-EG, HIF-1α, and TGF-ß are known as predictive factors. We performed this study to evaluate the role of bilateral uterine artery doppler ultrasound in predicting postmolar- GTN. Methods: In this prospective cohort study, 42 patients with complete molar pregnancy were examined. Inclusion criteria confirmed molar pregnancy by histopathological examination. Exclusion criteria were patients more than 40 years old, patients with completed family childbearing planning, and diagnosis of GTN during the routine histopathological study. Before molar evacuation and four weeks later, bilateral uterine artery doppler sonography to determine the PI, RI, and PSV was performed. Serum BHCG levels were also measured before molar evacuation and weekly after evacuation until it exhibited spontaneous remission or developed GTN. Results: About 36 patients were cured, and six others developed post-molar GTN. The bilateral uterine artery doppler sonography between the two groups showed a lower UA RI in the post-molar-GTN group before evacuation (P=0.048). Data demonstrated significant increases in Right.UA.RI (P=0/008), Left.UA.PI (P=0/037), and Right.UA.PSV (P=0/024) in the spontaneous remission group during 28 days follow-up period. There were no significant differences in these parameters in the GTN group throughout the time of follow-up. Conclusion: It seems that Doppler ultrasound plays a role in predicting GTN following uterine evacuation. A lower resistance in the uterine artery before evacuation and the remaining uterine artery blood flow constant after evacuation is associated with the development of post-molar- GTN.