Blood Flow Rate Research Articles

A hemodynamic study of the relationship between the left and right liver volumes and the blood flow distribution in portal vein branches.

Cirrhosis patients often exhibit clinical symptoms such as right liver atrophy, portal hypertension, spleen enlargement and increased blood supply, which exhibit considerable variation between the left and right liver sections. These differences are hypothesized to stem from disparities in blood flow within the left and right portal vein (PV) branches. However, rigorous quantitative evidence remains scarce. We mainly aim at quantitatively revealing the relationship between the blood flow rates of two PV branches and liver volumes, and providing quantitative evidence and theoretical support for the diagnosis and treatment of cirrhosis from the perspective of hemodynamics. Five cirrhotic patients and two healthy volunteers from Beijing Friendship Hospital are investigated. Their PV blood flow models are established based on computed tomography (CT) images and finite volume simulations. The volume of the left and right liver lobes are measured in 3-matic. The distributions of blood source in the PV branches are tracked by streamline analysis. The blood flow rates are quantitatively counted by integrating the blood source velocities. Linear analysis is performed to build the relationship between liver volumes and PV blood flow distributions. Streamline analysis reveals significant differences in blood distribution between the left and right PV branches. The majority of blood from the superior mesenteric vein (SMV) flowed into the right portal vein (RPV), while most blood from the splenic vein (SV) entered the left portal vein (LPV). The main PV pressure drop linearly increases with the SV blood velocity for all PV structures of patients and healthy volunteers. The flow rate ratio QRPV/QLPV demonstrates an increase in tandem with the volume ratio VR/VL, exhibiting a linear correlation with the Pearson correlation coefficient being 0.93. The differences in the blood distributions are consistent with the clinicians' knowledge and validate our simulations. We demonstrated a linear increase in PV pressure with elevated SV blood velocity. Additionally, the volumes of the left and right hepatic lobes exhibited a positive correlation with blood flow rates in the corresponding PV branches.

Effects of neuromuscular electrical stimulation, light intensity walking and a seated exercise trainer on venous return in healthy young adults: a quasi-experimental crossover study

Background/Aims The growing prevalence of sedentary behaviour across the life course is linked to an increased risk of chronic venous disease and related mortality, warranting the need for non-invasive interventions to improve blood flow and lower extremity function. The aim of this study was to investigate the change in venous blood flow, heart rate and blood pressure after 8 minutes of using the Leeper device, Circulation Booster and light intensity walking. Methods A quasi-experimental crossover study involving 11 participants (eight women, three men, mean age 23.91 years, standard deviation 1.04 years) was conducted using Leeper and Circulation Booster devices and light intensity walking. During each intervention, participants exercised for 8 minutes, and blood flow was recorded at 0, 4 and 8 minutes. Heart rate and blood pressure were recorded at 0 and 8 minutes. Blood flow was the primary outcome measure, and heart rate and blood pressure were secondary outcomes. Participants rested for 10 minutes between exercise. A two-way repeated measures analysis of variance was used to analyse the effect of intervention and time on blood flow, blood pressure and heart rate. Results There was no significant interaction between intervention and time on blood flow (P=0.180) indicating that blood flow did not change over time depending on intervention. There was no significant main effect of time on blood flow (P=0.206), indicating that no intervention caused a significant increase or decrease in blood flow after 8 minutes of exercise. Conclusions The interventions involving the Leeper and Circulation Booster devices and light intensity walking did not appear to significantly increase blood flow in young adults. Further studies involving participants from older age groups and those with pathological interventions are warranted to examine the potential effectiveness of these interventions. Implications for practice The findings may assist with the advice that allied health professionals provide regarding the use of seated exercise trainers and EMS devices and their ability to influence changes in blood flow.

Beyond traditional venous access: Midline catheter use in pediatric apheresis.

The objective of this study was to assess the use of midline catheters as venous access for apheresis procedures in pediatric patients. A retrospective analysis of medical records was conducted from September 2019 to June 2022 to evaluate the safety and efficacy of midline catheters for therapeutic pediatric apheresis. During the study period, a total of 121 procedures were inserted in 22 unique patients. The age of the subjects ranged from 2.7 to 21 years. The blood flow rates achieved with midline catheters met or exceeded the recommended rates for apheresis in children (40 mL/min), by the Wilcoxon signed-rank test (p < 0.0001). There was one episode of catheter-related thrombosis, but no cases of bloodstream infection or catheter dislodgement were reported. In conclusion, this study supports the use of midline catheters as a safe and effective alternative for venous access during therapeutic and donor apheresis procedures in pediatric patients.

Hemodialysis Procedures for Stable Incident and Prevalent Patients Optimize Hemodynamic Stability, Dialysis Dose, Electrolytes, and Fluid Balance.

The demographic profile of patients transitioning from chronic kidney disease to kidney replacement therapy is changing, with a higher prevalence of aging patients with multiple comorbidities such as diabetes mellitus and heart failure. Cardiovascular disease remains the leading cause of mortality in this population, exacerbated by the cardiovascular stress imposed by the HD procedure. The first year after transitioning to hemodialysis is associated with increased risks of hospitalization and mortality, particularly within the first 90-120 days, with greater vulnerability observed among the elderly. Based on data from clinics in Fresenius Medical Care Europe, Middle East, and Africa NephroCare, this review aims to optimize hemodialysis procedures to reduce mortality risk in stable incident and prevalent patients. It addresses critical aspects such as treatment duration, frequency, choice of dialysis membrane, dialysate composition, blood and dialysate flow rates, electrolyte composition, temperature control, target weight management, dialysis adequacy, and additional protocols, with a focus on mitigating prevalent intradialytic complications, particularly intradialytic hypotension prevention.

Application of therapeutic ultrasonic waves across the dialyzer membrane: A pilot study on the impact on dialyzer clearance and safety.

Progressive clogging of the dialyzer membrane during hemodialysis can compromise solute removal efficiency. Existing solutions fall short in addressing intradialytic reduction of dialyzer clearance. This pilot study aims to assess the impact and safety of applying therapeutic ultrasonic waves to dialyzers for mitigating intradialytic clogging. In this pilot study, 15 stable maintenance hemodialysis patients (12 males and 3 females) were enrolled. Each patient served as their own control. They underwent one session of hemodialysis with the application of therapeutic ultrasonic waves (Ultrasonic session) and were crossed-over to a second session without the use of ultrasonic waves (Control session). All the study sessions operated at a fixed dialysate flow rate of 500 mL/min and a blood flow rate of 250 or 300 mL/min. The adequacy of dialysis achieved during each session was monitored using Online Clearance Monitoring of the dialysis machines, and clearance K values, varying between 135 and 209 mL/min, were recorded, and plotted. A direct comparison between Control and Ultrasonic sessions was performed to assess the impact and safety of using ultrasonic waves during hemodialysis. The mean percentage decline in dialyzer clearance values was 4.41% for Ultrasonic sessions (SD: 5.3) and 12.69% for Control sessions (SD: 6.35) (p-value <0.001). This indicates that the application of ultrasonic waves reduced the decline in clearance values. The mean differences of the blood component parameters were comparable between both Ultrasonic sessions and Control sessions, suggesting the safety of utilizing ultrasonic waves during dialysis. Microscopic membrane analysis corroborated the safety. Intradialytic clogging of dialyzer membranes is a significant problem that can cause dialysis inadequacy. Our study tackles this issue by introducing therapeutic ultrasonic waves to improve dialyzer clearance during hemodialysis sessions in patients.

#326 Features of intrarenal hemodynamics in patients with chronic glomerulonephritis on the background of taking anticoagulants

Abstract Background and Aims Chronic glomerulonephritis (CGN)-glomerular, autoimmune kidney disease, where baseline therapy is clinically proven to be successful. The study evaluates hemodynamic disorders of renal blood flow in patients with CGN on the background of baseline treatment with the inclusion of rivaroxaban. Method We researched108 patients CGN against the background of 3-month basic therapy with the inclusion of rivaroxaban (group AC+, 55 patients) and without anticoagulant (group AC-, 53 patients). Initial and after 3 months evaluation in the mode of color Doppler mapping and pulse-wave doppler. Results In the course of 3-month therapy, the performance of dopplerography of renal arteries in patients with CGN did not change reliably. But there was a credible and clinically significant increase in the systolic blood flow rate at the level of the Interregional Artery (IA), both compared to the baseline data and towards the end of hospitalization (by 9.27 2.58% p &amp;lt; 0.001 the validity of the difference with the raw data, by 8.60 2.53%, p &amp;lt; 0.01 with the 10th day of therapy), remaining reliably lower than in control group (p &amp;lt; 0.001). The speed at the arc artery (АА) also increased slightly (by 2.46 1.03%, p &amp;lt; 0.05 reliability of the difference with the original data and the end of hospitalization), but although statistical reliability was achieved, the dynamics was clinically insignificant and was less than 2.5%. The resistivity index (RI) at both IA and AA levels did not change reliably. Conclusion In CGN patients, intrarenal hemodynamics change with decreased blood flow rates in IA and AA. In the future, against the background of 3-month basic HGH therapy, there was some improvement in blood flow at the IA level but not AA, but no qualitative changes in intrarenal hemodynamics were achieved. The supplementation of long-term anticoagulation therapy with rivaroxaban has increased the effect of therapy on hemodynamic rates, resulting in some improvement in blood flow at both IA and AA levels, but no qualitative improvement has been achieved, possible due to pronounced structural remodeling of kidney vessels in patients with CGN.

#1044 Quantitative analysis of dialytic protein loss with medium cut-off and high-flux membranes

Abstract Background and Aims Hemodialysis is an effective way for eliminating uremic retention products in patients with end-stage kidney disease. Medium cut-off membranes (MCO) were designed to enhance the dialytic removal of middle-sized molecules, such as beta-2 microglobulin (β2M). However, alongside these toxins, salutary proteins could also be lost. To better understand the spectrum of proteins cleared by MCO and high-flux (HF) dialyzers, we conducted qualitative and quantitative analysis of proteins in hemodialysis ultrafiltrate (UF). Method We established an ex vivo hemodialysis simulation system by using two Fresenius 2008T machines to concurrently dialyze a 2.5-liter human plasma reservoir for simultaneous testing of two dialyzers. We compared three dialyzers, including two HF dialyzers (Fresenius Medical Care Optiflux F180NR and FX CorAL 80), and an MCO membrane (Baxter Theranova 400; TH) (Fig. 1A). The blood flow rate was 400 mL/min, the dialysate flow rate was zero, and the ultrafiltration flow rate was 13 mL/min. UF samples were collected every 10 minutes from the UF line. Upon experiment completion at one-hour, residual filtrate was collected from the dialysate compartment. All samples were stored at −80°C until analysis. In total we conducted six dialysis simulations, each involving a concurrently tested dialyzer pair (Fig. 1B). UF samples underwent protein analysis (Bradford protein assay), albumin and creatinine measurement (Horiba® Pentra C400), liquid chromatography tandem mass spectrometry (LC-MS/MS)-based proteomics (Agilent® Q-TOF 6546), and immune-based protein assay (Luminex® Magpix). We analyzed the average of four sets of data obtained from the same dialyzer at the same time point. Results The loss of total protein and albumin was significantly greater with TH compared to the two HF dialyzers (Fig. 1C). Creatinine removal was similar across all dialyzers (Fig. 1D). The overall protein loss through F180NR and CorAL was comparable, while the protein loss through TH was up to 14-fold higher (811.7 ± 149.5 mg; Fig. 1E). Similar trends were observed for albumin. Albumin comprised 62% of the protein content in UF from TH, whereas it accounts for approximately 30% for HF dialyzers. We next employed label-free LC-MS and LC-MS/MS to identify and quantify proteins in 12 UF samples collected at the 20-minute point. Using Spectrum Mill software, we identified 244 proteins in the UF, 113 were accurately semi-quantified. The protein intensity ratios of TH-to- F180NR, TH-to-CorAL, and CorAL-to-F180NR for these 113 proteins are presented in Fig. 2A-C. Each gray dot on the plot corresponds to a specific protein. In line with the total protein and albumin quantification, MS proteomics analysis consistently revealed a greater loss of every identified protein by TH compared to both HF dialyzers. The median protein intensity ratio of TH-to-F180NR and TH-to-CorAL was 9.14 and 8.25, respectively. Importantly, TH not only removed middle-molecules such as β2M, but also showed a higher loss of salutary proteins. For instance, our data indicate a 9- to 16-fold difference in the level of albumin, haptoglobin, and vitamin D-binding protein between TH and HF dialyzers. Protein loss did not differ between F180NR and CorAL. To validate the accuracy of the MS quantification, we quantified seven proteins using immune-based assays in all UF samples at the 20-minute point. The result revealed a strong consistency between MS data and other methods (Fig. 2D). Conclusion We established an ex vivo system to concurrently test two dialyzers and implemented a robust proteomics workflow for a direct comparison of protein loss in the UF. Our data comprehensively and consistently indicate a greater extent of protein loss with MCO compared to HF, including the loss of salutary proteins. Further research is warranted to explore the clinical consequences of the enhanced loss of salutary proteins.

The effect of excessive gas to blood ratios in an ECMO oxygenator.

Oxygenators for paediatric Extracorporeal Membrane Oxygenation (ECMO) are required to operate over a wide range of flow rates, in a patient group ranging from neonates through to fully grown adolescents. ECMO oxygenators typically have a manufacturer's stated maximum gas: blood flow rate (GBFR) ratio of 2:1, however, many patients require greater ratios than this for adequate CO2 removal. Mismatches in GBFR in theory could result in high gas phase pressures. These increased pressures in theory could cause the formation of gross gaseous microemboli (GME) placing the child at higher risk of neurological injury. We evaluated 6 paediatric and 6 adult A.L.ONE™ ECMO oxygenators and assessed their gas phase pressures and GME release, in an ex vivo setting, in GBFR ratios up to greater than 2, across a range of gas flow (1L - 10L/min) rates with a fraction of inspired oxygen (FiO2) content of 50% and 100%. There were no increases above 10mmHg observed in gas phase pressures in GBFR >= 2:1 in either adult or paediatric oxygenators. Laboratory examination of GME activity demonstrated a small increase in post-membrane GME release over the study period. GME release was unaffected by FiO2 setting or gas flow rate, with a maximum volume of < 6µL in both paediatric and adult oxygenators. In an ex vivo setting, increasing GBFR above 2:1 in a paediatric oxygenator, and to a GBFR of 2:1 in an adult oxygenator did not significantly increase gas phase pressures, and no oxygenator membrane rupture was observed. There were no associations between gas flow rates and GME production.

#621 The effect of intra-operative mean arterial pressure on early graft function in deceased donor kidney transplantation

Abstract Background and Aims The adequate perfusion pressure to the graft is essential for proper graft function in kidney transplantation, especially in deceased donor kidney transplantation. In particular, Mean arterial pressure (MAP) during operation can affect early graft function because MAP is associated with renal blood flow and glomerular filtration rate. Therefore, the analysis of intra-operative parameters are necessary to evaluate adequate graft perfusion. The aim of this study is to investigate the relationship between intra-operative parameters including MAP and early graft function in deceased donor kidney transplantation. Method We retrospectively analyzed 363 recipients who underwent deceased donor kidney transplantation from March 2010 to December 2020. Anesthetic monitoring data during intraoperative period was analyzed and basic clinical parameters were evaluated. Results In total 363 recipients, the mean recipient age was 48.9 ± 10.3 and mean donor age was 48.2 ± 15.2. Anesthetic time was mean 285.9 ± 63.8 (min) and operation time was 226.4 ± 48.7 (min). Median value of baseline MAP and MAP at reperfusion were 124 mmHg and 88 mmHg. After initial analysis, the recipients were divided into two groups, high MAP group (n = 185) and low MAP group (n = 178), according to median value of baseline MAP (124 mmHg) and these two groups were analyzed. High MAP group showed higher estimated glomerular filtration rate (eGFR) and urine output compared to low MAP group during immediate postoperative 1 week. At postoperative day 5, eGFRs were 43.4 ± 26.7 and 37.3 ± 24.2 mL/min/1.73 m2 respectively (p = 0.022) and urine outputs were 2942.6 ± 1368.6 and 2474.3 ± 1199.1 mL respectively (p = 0.001). The incidences of delayed graft function showed no significant difference between two groups (2.2% vs 6.2%, p = 0.066). We additionally analyzed the effect of MAP at reperfusion, and the result showed that there was no significant relationship between MAP at reperfusion and early graft function. Conclusion In this retrospective study, MAP at reperfusion was not significantly related to early graft function and incidence of delayed graft function. In baseline MAP analysis, high baseline MAP group showed early recovery of eGFR and more urine output than low baseline MAP group. As a result, the recipients with high baseline MAP were related to early recovery of graft function in deceased donor kidney transplantation.

#1813 Safety and efficacy of reducing hemodialysis fluid flow rate—contribution to planetary health

Abstract Background and Aims Historically, increasing dialysate flow rates (Qd) have been recommended to improve hemodialysis (HD) efficiency. For decades, Qd has routinely been set to a fixed rate of 500 ml/min. A standard HD treatment uses on average around 500 L of water [1], resulting in a consumption of 78 000 L per patient and year with an additional estimated 10 000 L for post-dilution hemodiafiltration. This corresponds to the annual water consumption of 1.5 persons in developed countries and considerably more in developing countries. We investigated the effect of reducing dialysate flow rates on HD safety and efficacy. Method This is a prospective single-center non-blinded observational study. We investigated the effect of a 1:1 adjustment of online Qd to blood flow rate by adjusting autoflow (AF) settings of the dialysis monitor to a calculation factor of 1.0 with a lower Qd limit of 350 ml/min (AF 1.0 mode). We examined the effect on dialysis efficacy, metabolic markers, and anemia in routine biochemical analyses, and calculated energy, water, and waste savings in 116 stable chronic HD patients. Data were compared with previous turnover in energy, waste, and water, as well as with clinical results prior to the mentioned modifications. Results After 12 months of HD treatment with AF 1.0 mode we observed reductions of 10% in electricity consumption, 19% in raw water consumption, and 24% in dialysate concentrate consumption. Conversely, we did not observe deteriorations in treatment quality or dialysis dose (Table 1), nor phosphate or hemoglobin. Conclusion Long-term HD treatment with reduced dialysate fluid flow rates led to substantially improved water and carbon footprints with potential effects on planetary health and economic savings, while dialysis quality remained unchanged.

#1351 Assessment of safety and efficacy of expanded hemodialysis in comparison to HDF

Abstract Background and Aims In end-stage kidney disease, solutes with a wide spectrum of molecular weight, called uremic toxins, are retained due to impaired kidney cleansing capacity. Particularly, the retention of toxins in the middle molecular weight range 15–45 kDa might negatively affects multiple organ systems and metabolic pathways. The removal of such large uraemic toxins is still a challenge. HDF has produced some results although large convective volume, optimal vascular access to increase the blood flow rate and strict water quality management are required. Medium Cut-Off, high Retention Onset membrane have been recently developed introducing the concept therapy called “expanded haemodialysis” (HDx). Furthermore, vitamin E-coated membrane has potential beneficial effects on inflammation and oxidative stress. Method A prospective longitudinal single-center study was conducted for 3 months among 18 chronic haemodialysis patients. Patients were randomly assigned into either HDF with high flux membrane or HDx with Theranova or ViE-X membrane. The primary goal was to assess albumin loss among the three types of dialyzers. Secondary goals included assessment of depurative efficacy for uraemic toxins and clinical outcomes. Throughout the treatment, a proportional part of the dialysis fluid was collected to quantify albumin loss. Blood samples were taken before and after dialysis session in order to calculate the Removal Ratio and at two different intradialytic timepoints from arterial and venous line of the circuit in order to calculate instantaneous clearance. Results Mean albumin loss was significantly higher in patients undergoing HDx with Theranova membrane (ANOVA, p&amp;lt;0.001) without any difference in serum albumin concentration among the three groups. Instantaneous clearance of small and middle molecules was significantly higher in patients undergoing HDF, but we didn't find differences in removal ratio. Reduction of Erythropoietin resistance index was observed in patients treated with ViE-X membrane but it was related to their lower dialysis vintage. Conclusion HDx with Theranova membrane was associated with higher albumin loss without any effect on pre-dialysis serum albumin. Moreover, patients treated Theranova membrane, in the presence lower Qb, lower convective dose and lower instantaneous clearance reached same dialysis efficacy compared to HDF.

#1062 Effect of intradialytic resistance exercise on patient survival: a multicenter non-randomized cohort study

Abstract Background and Aims Intradialytic exercise significantly benefits the physical function of patients undergoing hemodialysis. Prior research into its impact on patient longevity has been constrained by small participant numbers and the lack of a control group. This study investigates the influence of exercise therapy during hemodialysis on patient lifespan in a broad multicenter cohort. Method This forward-looking, multicenter, non-randomized clinical investigation included 17 outpatient clinics from the Kaikoukai Medical Group, recruited between April and December 2018. Participants were voluntarily enlisted in an exercise regimen during their dialysis sessions and segregated into exercising and non-exercising cohorts. The trial was not blinded. The intradialytic regimen comprised stretching and four types of resistance exercises utilizing elastic tubes, conducted thrice weekly. Baseline data encompassing age, gender, stature, baseline weight, duration of hemodialysis treatment, and concurrent diabetic conditions were collected. Additional data regarding hemodialysis, including Kt/V ratio, hemodialysis blood flow rate (QB), dialysate volume (QD), and duration of dialysis, were recorded. Laboratory parameters such as albumin (Alb), calcium (Ca), potassium (K), hemoglobin (Hb), C-reactive protein (CRP), and creatinine (Cr) levels were extracted from medical records. Patient outcomes were monitored until either the occurrence of death or the study's culmination in December 2021. In statistical analyses, missing values were addressed using multiple imputation techniques, and baseline characteristics between groups were compared using an unpaired t-test. Cox proportional hazards regression analysis was employed to examine the relationship between the exercise intervention and survival, adjusting for multiple confounding variables. Three models were constructed for analysis: Model 1 incorporated basic patient data, Model 2 included hemodialysis parameters, and Model 3 involved laboratory data. The study was approved by the Ethical Committee of Nagoya Kyoritsu Hospital. Results The study encompassed 2006 subjects (average age 70.1±0.3 years), with 512 (25.5%) in the exercise group and 1494 (74.5%) in the control group. Initial comparisons indicated that the exercise group had significantly lower average height (160.9±0.3 vs. 159.7±0.4 cm, p=0.03), baseline weight (57.2±0.3 vs. 55.9±0.5 kg, p=0.04), Kt/V ratio (1.59±0 vs. 1.64±0, p=0.01), and QD (494±0.9 vs. 486.8±1.9 ml, p&amp;lt;0.01). Over the median observation period of 25 months, 338 (16.9%) patients, comprising 58 (11.3%) from the exercise group and 280 (18.7%) from the control group, succumbed. Survival analysis revealed a significant association between exercise intervention and mortality reduction, adjusted for confounders in Model 1 (HR 0.6, 95%CI 0.4-0.9, p=0.01), Model 2 (HR 0.55, 95%CI 0.37-0.8, p=0.02), and Model 3 (HR 0.57, 95%CI 0.38-0.87, p=0.01). Conclusion This research is the first to demonstrate a significant association between intradialytic resistance training and improved survival in hemodialysis patients within a multicenter, non-randomized cohort. This relationship remained significant after adjusting for multiple confounding factors, suggesting that incorporating resistance training into standard hemodialysis care could markedly enhance patient survival outcomes.

Computational study of haemodynamic change induced by the resuscitative endovascular balloon aortic occlusion

ABSTRACT Resusciative endovascular balloon aortic occlusion (REBOA) can be used in various surgical operations, especially in patients with hypotension and shock caused by traumatic main vascular rupture and massive haemorrhage. However, the hydrodynamic effects of surgery on aortic haemodynamics and organ perfusion are still unclear. Herein, computational fluid dynamic methods were used to evaluate the effect of balloon expansion and that of balloon-occluded aortic ratios on haemodynamics. The simulation shows that the balloon reduces the flow rate from the heart to the ruptured aorta. While reducing the flow rate of the aortic branches downstream of the balloon under conditions with fixed cardiac output, the balloon will increase the flow rate of the aortic branches upstream of the balloon. And the flow in the diastolic phase is more complicated than that of the systolic phase, and the vortex generated upstream of the balloon is more evident than that of the formed downstream. Moreover, when the inflation rate of the balloon changes rapidly, the flow rate of blood at the balloon changes suddenly accordingly, which generates a large additional pressure on the balloon. The pressure will spread upstream, thereby generating a blood hammer effect on the blood vessel wall.

Endometrial Elasticity is an Ultrasound Marker for Predicting Clinical Pregnancy Outcomes after Embryo Transfer.

Endometrial elasticity is a potential new marker for assessing endometrial receptivity and pregnancy outcomes based on endometrial thickness and type. Currently, little research has been conducted on the elasticity of the endometrium using shear wave elasticity imaging (SWEI). This study aimed to explore whether endometrial elasticity is an ultrasound marker for predicting clinical pregnancy outcomes after embryo transfer. A total of 245 infertile women underwent ultrasonography before embryo transfer at the Peking University Third Hospital. We compared the endometrial elasticity and sub-endometrial blood flow rate using SWEI in the groups with different pregnancy outcomes. Trends in clinical pregnancy outcomes across the quartiles of endometrial elasticity in the fundus of the uterus (E1) were assessed. Logistic regression analysis was performed to obtain odds ratios for clinical pregnancy outcomes based on the quartiles of E1, with or without adjusting for potential confounding variables. Women in the clinical pregnancy group had higher E1 values and sub-endometrial blood flow rates in the uterine fundus than those in the non-pregnancy group. Women in the highest quartile of E1 had the most favorable clinical pregnancy rates. Endometrial elasticity measured using SWEI is a promising ultrasound marker for predicting clinical pregnancy outcomes after embryo transfer.

Impact of stage-specific limb function exercises guided by a self-management education model on arteriovenous fistula maturation status.

The exercise of limb function is the most economical and safe method to promote the maturation of arteriovenous fistula (AVF). However, due to the lack of a unified exercise standard in China, many patients have insufficient awareness of the importance of AVF, leading to poor effectiveness of limb function exercise. The self-management education model can effectively promote patients to take proactive health-related actions. This study focuses on the characteristics of patients during the peri-AVF period and conducts a phased limb function exercise under the guidance of the self-management education model to observe changes in factors such as the maturity of AVF. To assess the impact of stage-specific limb function exercises, directed by a self-management education model, on the maturation status of AVFs. This study is a randomized controlled trial involving 74 patients with forearm AVFs from the Nephrology Department of a tertiary hospital in Sichuan Province, China. Patients were randomly divided into an observation group and a control group using a random number table method. The observation group underwent tailored stage-specific limb function exercises, informed by a self-management education model which took into account the unique features of AVF at various stages, in conjunction with routine care. Conversely, the control group was given standard limb function exercises along with routine care. The assessment involves the maturity of AVFs post-intervention, postoperative complications, and the self-management level of the fistula in both groups patients. Analyses were conducted using SPSS version 23.0. Count data were represented by frequency and percentage and subjected to chi-square test comparisons. Measurement data adhering to a normal distribution were presented as mean ± SD. The independent samples t-test was utilized for inter-group comparisons, while the paired t-test was used for intra-group comparisons. For measurement data not fitting a normal distribution, the median and interquartile range were presented and analyzed using the Wilcoxon rank sum test. At the 8-wk postoperative mark, the observation group demonstrated significantly higher scores in AVF symptom recognition, symptom prevention, and self-management compared to the control group (P < 0.05). However, the variance in symptom management scores between the observation and control groups lacked statistical significance (P > 0.05). At 4 wk after the operation, the observation group displayed a superior vessel diameter and depth from the skin of the drainage vessels in comparison to the control group (P < 0.05). While the observation group did manifest elevated blood flow rates in the drainage vessels relative to the control group, this distinction was not statistically significant (P > 0.05). By the 8-wk postoperative interval, the observation group outperformed the control group with notable enhancements in blood flow rates, vessel diameter, and depth from the skin of drainage vessels (P < 0.01). Seven days following the procedure, the observation group manifested significantly diminished limb swelling and an overall reduced complication rate in contrast to the control group (P < 0.05). The evaluation of infection, thrombosis, embolism, arterial aneurysm stenosis, and incision bleeding showed no notable differences between the two groups (P > 0.05). By the 4-wk postoperative juncture, complications between the observation and control groups were statistically indistinguishable (P > 0.05). Stage-specific limb function exercises, under the guidance of a self-management education model, amplify the capacity of AVF patients to discern and prevent symptoms. Additionally, they expedite AVF maturation and mitigate postoperative limb edema, underscoring their efficacy as a valuable method for the care and upkeep of AVF in hemodialysis patients.

Improved MRI methods to quantify retinal and choroidal blood flow applied to a model of glaucoma.

Blood flow (BF) of the retinal and choroidal vasculatures can be quantitatively imaged using MRI. This study sought to improve methods of data acquisition and analysis for MRI of layer-specific retinal and choroidal BF and then applied this approach to detect reduced ocular BF in a well-established mouse model of glaucoma from both eyes. Quantitative BF magnetic resonance imaging (MRI) was performed on glaucomatous DBA/2J and normal C57BL/6J mice. Arterial spin labeling MRI was applied to image retinal and choroidal BF using custom-made dual eye coils that could image both eyes during the same scan. Statistics using data from a single eye or two eyes were compared. BF values were calculated using two approaches. The BF rate per quantity of tissue was calculated as commonly done, and the peak BF values of the retinal and choroidal vasculatures were taken. Additionally, the BF rate per retinal surface area was calculated using a new analysis approach to attempt to reduce partial volume and variability by integrating BF over the retinal and choroidal depths. Ocular BF of both eyes could be imaged using the dual coil setup without effecting scan time. Intraocular pressure was significantly elevated in DBA/2J mice compared to C57BL/6J mice (P<0.01). Both retinal and choroidal BF were significantly decreased in DBA/2J mice in comparison to the age-matched normal C57BL/6J mice across all measurements (P < 0.01). From simulations, the values from the integrated BF analysis method had less partial volume effect, and from in vivo scans, this analysis approach also improved power. The dual eye coil setup allows bilateral eye data acquisition, increasing the amount of data acquired without increasing acquisition times in vivo. The reduced ocular BF found using the improved acquisition and analysis approaches replicated the results of previous studies on DBA/2J mice. The ocular hypertensive stress-induced BF reduction found within these mice may represent changes associated with glaucomatous progression.

Transcriptomics reveals age-related changes in ion transport-related factors in yak lungs.

Yaks inhabit high-altitude, low-oxygen regions, where ion transport functions play a crucial role in maintaining intracellular and extracellular ionic balance and regulating pulmonary vascular tension. These functions affect pulmonary ventilation and blood flow rate, aiding tissue development and enhancing oxygen transfer efficiency, thus facilitating better adaptation to hypoxic environments. To investigate the regulatory mechanisms of ion transport-related factors on the growth and development of yak lungs, we employed RNA sequencing (RNA-seq)for sequencing the transcriptome in the lung tissues of neonatal (1-day-old), juvenile (1-year-old), and adult (4-year-old) yaks. We also performed differential gene expression and functional analyses. The results yielded 26 genes associated with ion transport, mainly enriched in the salivary and pancreatic secretion pathways. Finally, we used several methods including quantitative polymerase chain reaction (qRT-PCR), and Western blotting (WB), immunohistochemical (IHC) and immunofluorescence (IF) staining to determine the distribution of the expression of the ion transport genes FOXI1, KCNMA1, and SLC12A2 in yak lung tissues. qRT-PCR and WB results indicated that mRNA and protein relative expression levels of FOXI1 and SLC12A2 were significantly higher in neonatal yaks than in juvenile and adult yaks (all p < 0.05), whereas those of KCNMA1 were significantly higher in adult yaks than in neonatal and juvenile yaks (all p < 0.05). IHC and IF results demonstrated that FOXI1, KCNMA1, and SLC12A2 were distributed among the epithelial mucosal layers (including ciliated, goblet, and Clara cells) of the yaks' bronchi and their branches in the lungs across different age groups of yak. Therefore, our results suggested that FOXI1, KCNMA1, and SLC12A2 may be strongly associated with the development and aging processes in yak lungs. These results provide insights into the molecular mechanisms underlying the yak's adaptation to high-altitude environments and valuable references for further research.

South African flag sign: A Red Flag in ECG

A method is developed to allow cardiologists to find changes in the blood flow rate in larger coronary arteries, caused by the appearance of their pathological tortuosity, and a hemodynamic significance of those changes based on the data taken from the appropriate coronarographies only. This method is based on replacement of blood flows in the originally healthy and subsequently pathologically tortuous artery with the corresponding averaged ones, and subsequent calculation of flow characteristics of interest in terms of the corresponding averaged flow characteristics. It allows one not to take account of a number of identical factors for the originally healthy and subsequently pathologically tortuous segment of the investigated artery, and gives one the possibility to determine the flow parameters of concern at any time after carrying out a coronarography. In addition, it is not associated with solving complicated technical problems, and does not require special facility to be used, special professional training and significant financial and temporal expenses. The method was successfully tested in-vitro and then applied to appropriate patients. It was found that the hemodynamic significance of the tortuosity generally increases/decreases as the number of the tortuosity arcs increases/decreases. Also, strong correlation between fundamental geometric and hemodynamic characteristics of the tortuosity and basic clinical indicators of the corresponding patients was established. This suggests a strong independent influence of the tortuosity on the clinical symptoms of the corresponding patients. The critical values for the number of the tortuosity arcs, the relative blood flow rate loss and the rate of angina.

Using DFT on ultrasound measurements to determine patient-specific blood flow boundary conditions for computational hemodynamics of intracranial aneurysms

Boundary conditions (BCs) is one pivotal factor influencing the accuracy of hemodynamic predictions on intracranial aneurysms (IAs) using computational fluid dynamics (CFD) modeling. Unfortunately, a standard procedure to secure accurate BCs for hemodynamic modeling does not exist. To bridge such a knowledge gap, two representative patient-specific IA models (Case-I and Case-II) were reconstructed and their blood flow velocity waveforms in the internal carotid artery (ICA) were measured by ultrasonic techniques and modeled by discrete Fourier transform (DFT). Then, numerical investigations were conducted to explore the appropriate number of samples (N) for DFT modeling to secure the accurate BC by comparing a series of hemodynamic parameters using in-vitro validated CFD modeling. Subsequently, a comprehensive comparison in hemodynamic characteristics under patient-specific BCs and a generalized BC based on a one-dimensional (1D) model was conducted to reinforce the understanding that a patient-specific BC is pivotal for accurate hemodynamic risk evaluations on IA pathophysiology. In addition, the influence of the variance of heart rate/cardiac pulsatile period on hemodynamic characteristics in IA models was studied preliminarily. The results showed that N ≥ 16 for DFT model is a decent choice to secure the proper BC profile to calculate time-averaged hemodynamic parameters, while more data points such as N ≥ 36 can ensure the accuracy of instantaneous hemodynamic predictions. In addition, results revealed the generalized BC could overestimate or underestimate the hemodynamic risks on IAs significantly; thus, patient-specific BCs are highly recommended for hemodynamic modeling for IA risk evaluation. Furthermore, this study discovered the variance of heart rate has rare influences on hemodynamic characteristics in both instantaneous and time-averaged parameters under the assumption of an identical blood flow rate.

Ineffective matching of oxygen supply to myocardial metabolism in primiparous compared to nulliparous swine

Maternal mortality rates in the United States are higher than any other developed country in the world. Most postpartum maternal deaths are directly related to adverse cardiovascular events and often occur in mothers who have had a healthy pregnancy. Although pregnancy is recognized as a cardiovascular stress test for the pregnant patient, understanding of how the longitudinal and dynamic cardiovascular adaptations during pregnancy contribute to augmented risk of cardiovascular complications through the postpartum period remains poorly understood. We propose that pregnancy-induced adaptations in the coronary circulation contribute to adverse cardiovascular outcomes, especially during the puerperium period (1-60 days following delivery). Accordingly, this study tested the hypothesis that the balance between coronary blood flow and myocardial metabolism is compromised in the puerperium heart. Experiments were performed in anesthetized, open-chest control nulliparous (control) and primiparous (postpartum) swine during the puerperium period (35-45 days post-delivery). Systemic and coronary hemodynamic responses were assessed under baseline conditions and in response to continuous intravenous infusion of dobutamine (1 – 30 μg/kg/min). Under baseline conditions, blood pressure averaged 107 ± 6 mmHg in both control and postpartum swine and was unaffected by dobutamine administration (P = 0.94). Heart rate increased from 77 ± 6 to 165 ± 9 beats/min in response to dobutamine in control swine vs. 52 ± 3 to 139 ± 13 beats/min in postpartum swine (P = 0.53). Coronary blood flow and myocardial oxygen delivery were significantly diminished by ~60 ± 8% at rest in postpartum swine, which is consistent with reduced myocardial oxygen consumption (MVO2). The relationship between coronary blood flow and heart rate (P &lt; 0.0001) or MVO2 (P = 0.0002) showed a marked parallel downward shift in postpartum swine at rest and in response to dobutamine infusion. This reduction in myocardial perfusion was associated with significant reductions in myocardial lactate uptake at rest in postpartum vs. control (0.34 μmol/min/g vs. 0.08 μmol/min/g, P = 0.02). Dobutamine increased myocardial lactate uptake in control by ~47 ± 3% with little change in the postpartum group. Together, these results suggest an ineffective matching of myocardial oxygen supply to metabolism in postpartum swine. This imbalance is consistent with increased incidence of myocardial ischemia and cardiac deaths in postpartum puerperium period. This work was supported by AHA.23PRE101281, NIH R01 HL158723. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.