Changes In Flow Volume Research Articles

Numerical simulation and fast method for the 0D-1D multi-scale coupled model and its application in ischemic brain tissue blood flow problems.

As living standards rise, more and more people are paying attention to their own health, especially issues such as cerebral thrombosis, cerebral infarction, and other cerebral blood flow problems. An accurate simulation of blood flow within cerebral vessels has emerged as a crucial area of research. In this study, we focus on microcirculatory blood flow in ischemic brain tissue and employ a 0D-1D geometric multi-scale coupled model to characterize this process. Given the intricate nature of human cerebral vessels, we apply a numerical method combining the finite element method and the third-order Runge-Kutta method to resolve the coupled model. To enhance computational efficiency, we introduce a fast method based on the reduced-order extrapolation algorithm. Our numerical example underscores the stability of the method and convergence accuracy to , while significantly improving the accuracy and efficiency of blood flow simulation, making the mechanism analysis more accurate. Additionally, we present examples detailing variations and distribution of intracranial pressure and blood flow in ischemic brain tissue throughout a cardiac cycle. Both reduced vascular compliance and vascular stenosis can have adverse effects on intracranial cerebral pressure and blood flow, leading to insufficient local oxygen supply and negative effects on brain function. Meanwhile, there will also be corresponding changes in volume flow and pulsatile blood pressure.

Long-term outcome of multilayer flow modulator in aortic aneurysms.

This retrospective study investigated the efficacy of endovascular treatment with multilayer flow modulators (MFMs) for treating aortic aneurysms in high-risk patients unsuitable for conventional treatments. Conducted from 2011 to 2019 at a single center, this retrospective observational study included 17 patients who underwent endovascular treatment with MFMs. These patients were selected based on their unsuitability for traditional surgical or endovascular procedures. The study involved meticulous pre-procedural planning, precise implantation of MFMs, and follow-up using CT angiography. The primary focus was on volumetric and flow volume changes in aneurysms, along with traditional diameter measurements. Moreover, the technical success and post-procedural complications were also registered. The technical success rate was 100%, and 30-day procedural complication rate was 17.6%. Post-treatment assessments revealed that 11 out of 17 patients showed a decrease in flow volume within the aneurysm sac, indicative of a favorable hemodynamic response. The median decrease in flow volume was 12 ml, with a median relative decrease of 8%. However, there was no consistent reduction in aneurysm size; most aneurysms demonstrated a median increase in volume for 46 ml and median increase in diameter for 18 mm. While MFMs offer a potential alternative for high-risk aortic aneurysm patients, their effectiveness in preventing aneurysm expansion is limited. The results suggest that MFMs can provide a stable hemodynamic environment but do not reliably reduce aneurysm size. This underscores the need for ongoing vigilance and long-term monitoring in patients treated with this technology.

Association of radiocephalic arteriovenous anatomical markers with post-angioplasty blood flow volume.

Doppler ultrasound (DUS) blood volume flow (VF) calculation is the most reliable method for demonstrating the success of endovascular treatment of dysfunctional radiocephalic arteriovenous fistula (AVF). Due to the difficulty of this method for the interventionalist, VF-correlated markers are required during the procedure. To investigate the relationship between intraprocedural anatomical markers (AMs) and changes in VF induced by percutaneous transluminal angioplasty (PTA). The study included 56 patients with dysfunctional radiocephalic AVF who underwent PTA between September 2020 and 2022. The VF of all patients was measured using DUS before and 1 h after PTA. AMs were determined from 10 images, five before and five after balloon angioplasty. The mean post-PTA VF was 637 ± 277 mL/min compared to baseline (151 ± 107 mL/min). Before and after balloon angioplasty, vein diameter (VD), artery diameter (AD), stenosis minimum luminal diameter (MLD), stenosis percentage (SP), and VF values were statistically significant (P = 0.001). Spearman's correlation analysis showed a positive strong linear relationship between VF and MLD (rs = 0.850, P <0.001), and a negative strong linear relationship between VF and SP (rs = 0.815). Receiver operating characteristic curve analysis showed that the sensitivity and specificity for VF ≥400 mL/min at cutoffs of SP <50% and MLD >2.5 mm were 81% and 82%, and 81% and 90%, respectively. Among the AMs readily available during PTA, first MLD and then SP provided satisfactory results in predicting VF.

Flow volume mismatch dramatically affects transient neurologic symptoms after direct bypass in Moyamoya disease.

Transient neurological events (TNEs) occur after bypass surgery in Moyamoya disease (MMD); however, their pathology remains unknown. To elucidate the pathophysiology of TNEs, we investigated their relationship with perioperative superficial temporal artery (STA) blood flow volume, which was evaluated using ultrasonography. Forty-nine patients with MMD, who underwent direct bypass surgery, were included and stratified into TNE and non-TNE groups, respectively. The STA blood flow volume was evaluated at four time points (preoperatively and 2-4, 7, and 10-14days postoperatively), and a change in volume during the postoperative period was defined as a flow volume mismatch. We investigated the association between ultrasonographic findings of flow volume mismatch and TNEs and magnetic resonance imaging findings, such as the cortical hyperintensity belt (CHB) sign, using univariate and path analyses. The STA blood flow volume increased immediately postoperatively, gradually decreasing over time, in both groups. The TNE group showed a significant increase in blood flow volume 2-4days postoperatively (P = 0.042). Flow volume mismatch was significantly larger in the TNE group than in the non-TNE group (P = 0.020). In the path analysis, STA flow volume mismatch showed a positive association with the CHB sign (P = 0.023) and TNEs (P = 0.000). Additionally, the CHB sign partially mediated the association between STA flow volume mismatch and TNEs. These results suggest that significantly high STA blood flow volume changes occurring during the acute postoperative period after direct bypass surgery in MMD are correlated with TNEs and the CHB sign, suggesting involvement in the pathophysiology of TNEs.

#4626 EFFECTS OF HEMODYNAMIC PARAMETERS OF THE BRACHIAL ARTERY ON AVF FLOW

Abstract Background and Aims Arteriovenous fistula (AVF) remains the preferred form of vascular access for hemodialysis, although dealing with the high rate of maturation failure. Many factors are found to be influencing the AVF outcome, however the diameter of the blood vessels, both arteries and veins, is recognized as the most important predictor. Aim of this study was to evaluate hemodynamic parameters of the brachial artery (Ab) on the change of volume flow (VF) during AVF maturation. Method This single-centre observational study included patients in whom AVF was created between September 2021 and December 2022. All patients underwent pre-operative physical and Color Doppler Ultrasound (CDU) measurements of the radial artery (Ar), brachial artery and cephalic vein (Vc). AVF maturation was evaluated by CDU consecutively 1, 14 and 28 days after AVF creation. As the hemodynamic parameters of the arteries, peak systolic volume (PSV), end-diastolic volume (EDV) and resistance index (RI) were measured. Results Study included 33 patients (81.8% male, mean age 64±10). VF was 346.55±126.86, 491.26±183.51, and 608.28±275.10 at day 1, 14 and 28, respectively (p = 0,000). Univariate regression analysis showed PSV (Beta = 0,456; p = 0,008) and EDV (Beta = 0,551; p = 0,001), both measured on Ab at day 1 post-AVF creation, are statistically significant predictors of flow change during 28 days of maturation. In the linear regression model EDV measured on Ab at day 1 post-AVF creation (Beta = 0,683; p = 0,003) and diameter of Ab (Beta = 0,441; p = 0,004) remained significant (Fig. 1 and 2). The vast majority of the study population undergone the first AVF puncture between 15-30th day post-creation (48.5%), while 12 (36.4%) and 5 (15.1%) experienced AVF puncture after more than 30 days and at the 14th day, respectively Conclusion Hemodynamic parametres of the brachial artery, precisely peak systolic volume and end-diastolic volume at the first day post-AVF creation, play a significant role in AVF maturation. CDU measurements of those hemodynamic parameters at day 1 may be useful for an early identification of AVF maturation outcomes.

Assessment of Cerebral Arterial Flow Volume Changes with Carotid Vertebral Artery Duplex Doppler Ultrasound in Young-Middle-aged Subclinical Hashimoto Thyroiditis Patients.

To demonstrate cerebral arterial flow volume changes during the hypothyroid, euthyroid, and hyperthyroid phases and comparing between laboratory findings and cerebral arterial flow changes with carotid-vertebral duplex Doppler ultrasound (CVA-DUSG) in subclinical Hashimoto thyroiditis (HT) patients. According to the TSH level, 3 groups were constructed between patient cases. Group 1 (n=29) was the subclinical hyperthyroid group. In this group, the TSH level was between 0.0005 and 0.3 IU/ml. Group 2 (n=175) was the euthyroid group. TSH level in this group was between 0.3 and 4.2 IU/ml. Group 3 (n=76) was the subclinical hypothyroid group. In this group, the TSH level was above 4.2 IU/ml. The control-group (group 4) (n=71) included healthy people. In this group, the TSH level was between 0.3 and 4.2 IU/ml. After obtaining at least three consecutive waves from the bilateral internal cerebral artery and bilateral vertebral artery, volume flows were calculated using CVA-DUSG. Volume flows were calculated as peak systolic velocity + end diastolic velocity/2 × mean arterial diameter. The mean ICA(Internal Carotid Artery) and VA(Vertebral Artery) diameter was measured per ICA and VA. Total cerebral artery flow volume was defined as right ICA + right VA flow volume and left ICA + left VA flow volume. We also demonstrated topographic cerebral artery blood flow changes. Total ICA flow volume was used to assess the anterior part of the brain, total VA flow volume was used to evaluate the posterior part of the brain, right ICA + right VA flow volume was used to assess the right part of the brain, and left ICA + left VA flow volume was used to verify the left part of the brain. There were significant differences between RVA(Right Vertebral Artery) flow volume, LICA (Left Internal Carotid Artery) flow volume, total flow volume, TSH, and T3 and T4 levels in all groups according to the Dunn's multiple comparison test.(p<0.001) Mean TSH level was 0.03 (0.005-0.06) IU/ml in group 1, 2.8 (1.8-3.97) IU/ml in group 2, 7.32 (6.14-9.93) IU/ml in group 3, and 1.76 (1.17-2.49) IU/ml in the control group. The mean T3 level was 4.18 (3.55-5.38) in group 1, 2.88 (2.63-3.16) in group 2, 2.82 (2.49-3.15) in group 3, 3.14 (2.92-3.15) in the control group. The mean T4 level was 1.92 (1.29-2.5) in group 1, 1.16(1.03-1.31) in group 2, 1.01 (0.91-1.16) in group 3, 1.12 (0.97-1.30) in the control group (group 4). Mean total flow volume was 793 (745-898) ml/min in group 1, 742 (684.25-822.5) ml/min in group 2, 747 (692-824) ml/min in group 3, and 700 (673-675) ml/min in the control group. We also demonstrated topographic cerebral arterial volume flow changes with CVA-DUSG. There was a significant difference among all groups in the right and anterior parts of the brain (p < 0.001), and there was a significant difference between groups 1 and 4 in the left part of the brain (p = 0.009). This study demonstrated that total cerebral arterial volume flow increased in the hyperthyroid phase of subclinical HT cases without any internal carotid and vertebral artery diameter changes compared with the euthyroid and hypothyroid phases of subclinical HT and healthy cases. We also verified topographic cerebral arterial blood flow changes in subclinical HT cases with a real-time, easily applicable modality (CVA-DUSG) that does not include X-ray or contrast agents. There was a significant difference between all groups in the right and anterior parts of the brain and there was a significant difference between groups 1 and 4 in the left part of the brain.

Effects of percutaneous transluminal angioplasty and associated factors in access hand oxygenation in patients undergoing hemodialysis

In hemodialysis (HD) patients with arteriovenous fistula (AVF), changes in systemic or peripheral tissue circulation occur non-physiologically via the presence of AVF; however, associations between blood flow and tissue oxygenation in the brain and access hand are uncertain. In this study, 85 HD patients with AVF were included and evaluated for changes in flow volume (FV) and regional oxygen saturation (rSO2) in the brain and hands with AVF before and after percutaneous transluminal angioplasty (PTA). Furthermore, we evaluated the factors that determine access hand rSO2 without stenosis after PTA. Brachial arterial FV increased after PTA (p < 0.001), and carotid FV decreased (p = 0.008). Access hand rSO2 significantly decreased after PTA (p < 0.001), but cerebral rSO2 did not significantly change (p = 0.317). In multivariable linear regression analysis of factors associated with access hand rSO2, serum creatinine (standardized coefficient: 0.296) and hemoglobin (standardized coefficient: 0.249) were extracted as independent factors for access hand rSO2. In conclusion, a decrease in access hand oxygenation and maintenance of cerebral oxygenation were observed throughout PTA. To maintain access hand oxygenation, it is important to adequately manage Hb level and maintain muscle mass, in addition to having an AVF with appropriate blood flow.

Pulsatility index-adjusted doppler flow measurement of pedal arteries in peripheral artery disease patients.

To examine the feasibility of using pulsatility index-adjusted (PI) flow equations to accurately characterize blood volume flow changes using Doppler technique in patients with peripheral artery disease (PAD) before and after percutaneous transluminal angioplasty (PTA). PTA was performed on 17 PAD patients (23 target vessels treated, 16 anterior tibial arteries, and 7 posterior tibial arteries). Arterial diameter, peak systolic velocity, PI, time-averaged mean velocity, and measured volume flow (MVF) of dorsalis pedis artery (DPA) and common plantar artery (CPA) were measured with duplex Doppler ultrasound before and after PTA. PI-adjusted volume flows (PIVF) were calculated as part of the MVF/PIVF relative percentage metric. Significant changes (p < 0.001) of the MVF (mean: 33.0 mL/min, range: -20.9-102.2 mL/min) and MVF/PIVF relative percentages (mean: 51.8, range: 5.1-127.2%) in the DPA existed between before and after PTA, whereas no significant changes could be found in the CPA (mean:10.9 mL/min, p = 0.148 and mean: 21.3%, p = 0.146, respectively). Of the 7 treated posterior tibial arteries, the increments of the MVF/PIVF (mean: 60.4%, p = 0.033) was significant but not in the MVF (mean: 26.5 mL/min, p = 0.125). The ankle-brachial index also showed non-significant changes (p = 0.081). All PI-adjusted results matched clinical observations after blood flow restoration. No conclusions can be drawn from the comparison of actual measured volume flow between before and after PTA. However, using the MVF/PIVF relative percentage allows for a more objective framework upon which to base clinical observations and provides clarity in situations where direct measurement provides a counter-intuitive or contradictory picture.

Experimental study on the influence of dielectric barrier discharge plasma on the atomization characteristics of aviation kerosene

In order to study the influence law of active particles on atomization characteristics of aviation kerosene and explore the key technologies of plasma application in fuel atomization auxiliary, the dielectric barrier discharge plasma nozzle was independently designed, and the experiments of He plasma jet spectrum diagnosis and fuel atomization characteristic were carried out. The active particle composition of He plasma jet was explored, and the influence of He volume flow rate and peak voltage on electron excitation temperature, SMD and spray cone angle were studied. The results show that He plasma ionizes the air in the surrounding space to produce active particles such as OH, O and He Ⅰ atoms. The electron excitation temperature varies between 3100 and 7300 K and reaches the maximum when the peak voltage is 11 kV. The influence of electric field application and He volume flow changes on the atomization characteristics are very obvious, specifically, as the peak voltage increases, the SMD decreases and the spray cone angle increases. Under the high peak voltage (12–13 kV), the increasing trend of the spray cone angle gradually slows down and stabilizes. As the volume flow of He increases, the SMD decreases and the spray cone angle increases. The difference in oil supply pressure will affect the atomization effect of plasma excited fuel. The specific realization is that under △Pinj = 0.05 MPa, the increase of He volume flow has little effect on the atomization effect. When △Pinj = 0.15–0.35 MPa, the change of peak voltage has a greater impact on SMD, while at a lower △Pinj (0.05–0.25 MPa), the change of peak voltage has a greater impact on the growth trend of the spray cone angle.

Flexible Doppler ultrasound device for the monitoring of blood flow velocity.

Thrombosis and restenosis after vascular reconstruction procedures may cause complications such as stroke, but a clinical means to continuously monitor vascular conditions is lacking. Conventional ultrasound probes are rigid, particularly for postoperative patients with fragile skin. Techniques based on photoplethysmography or thermal analysis provide only relative changes in flow volume and have a shallow detection depth. Here, we introduce a flexible Doppler ultrasound device for the continuous monitoring of the absolute velocity of blood flow in deeply embedded arteries based on the Doppler effect. The device is thin (1 mm), lightweight (0.75 g), and skin conforming. When the dual-beam Doppler method is used, the influence of the Doppler angle on the velocity measurement is avoided. Experimental studies on ultrasound phantoms and human subjects demonstrate accurate measurement of the flow velocity. The wearable Doppler device has the potential to enhance the quality of care of patients after reconstruction surgery.

Immediate complications and flow volume changes during treatment phases of bronchial thermoplasty: a single-center descriptive study

Introduction Bronchial thermoplasty (B.T.) is a therapeutic bronchoscopic procedure in which controlled thermal energy is applied to the airway wall to decrease smooth muscle mass. Immediate complications of B.T. include acute exacerbation of bronchial asthma, upper and lower respiratory tract infection, hemoptysis, among others. Our study assessed these immediate adverse events and the changes in forced expiratory volume in one second (FEV1%) measured four hours after each procedure from baseline. The study also aimed to examine the number of activations during each cycle of treatment and its correlation to the corresponding change in FEV1% from baseline. Methods A case-series analysis of 17 patients who underwent B.T. between 2014 and 2019 was done. Demographic, clinical characteristics, including pre and post-BT FEV1% measures, and the number of activations were obtained. Results Acute exacerbation of asthma was the commonest complication accounting for 33%, 57%, and 75% after BT1, BT2, and BT3, respectively. There was deterioration in FEV1% after each treatment phase, the most significant being in BT3. There was no correlation between the number of heat activations with the change in FEV1% from baseline. Conclusion The number of activations in B.T. does not correlate with the immediate deterioration in FEV1%, although exacerbation of asthma is the commonest complication post-B.T.

4D flow MRI: impact of region of interest size, angulation and spatial resolution on aortic flow assessment

Objectives. In cardiovascular magnetic resonance, the 3D time-resolved phase-contrast technique, also known as 4D flow, is gaining increasing attention due to applications that exploit three-directional velocity encoding throughout the cardiac cycle. Blood flow volume assessment usually requires an expert to draw regions of interest (ROI) around the vessel cross section, whereas the errors involved in this estimation have not been thoroughly investigated. Our objective is to quantify the influence of ROI sizing, angulation and spatial resolution of the reconstructed plane employed in blood flow measurements using 4D flow. Approach. Three circular ROIs were drawn around the ascending, arch and descending aorta of healthy volunteers (n = 27) and patients with a dilated ascending aorta or bicuspid valve (n = 37). We applied systematic changes of ROI diameter (up to ±10%), tilt angle (up to ±25°) and spatial resolution (from 0.25 to 2 mm) of the reconstructed oblique planes, calculating the effects on net, forward and backward blood flow volumes. Main results. Patients had a larger ascending aorta than healthy volunteers with similar ages and male sex proportion (60 ± 15 y.o. vs 58 ± 16 y.o. and 84% vs 70%, respectively). Higher forward and backward flow volumes were observed in the ascending aorta and the aortic arch of the patients with respect to controls (p < 0.001), whereas net volumes were similar: 74.0 ± 20.8 ml versus 75.7 ± 21.8 ml (p = 0.37), respectively. The ascending aorta was the most sensitive to ROI modifications. Changes of ±10% in the ROI diameter and ±25° in tilt angles produced flow volume differences of up to 9 ml (10%) and 18 ml (15%) in controls and patients, respectively. Modifying the reconstructed planes spatial resolution produced flow volume changes below 2 ml. Significance. Since the setting of the ROI size and plane angle could produce errors that represent up to 20% of the forward and/or backward aortic flow volume, a good standardization for vessel segmentation and plane positioning is desirable.

CAR 5. Carotid Flow Volume Measurement in Doppler Ultrasound as a New Look at the Diagnosis of Internal Carotid Artery Stenosis

Blood flow velocity criteria in the diagnosis of carotid stenosis are well defined; however, there are no reference values concerning blood flow volume. The objective of this work covered assessment of blood flow volume in the internal carotid artery (ICA), external carotid artery (ECA), and vertebral artery (VA) in healthy volunteers and asymptomatic patients with carotid artery disease older than 65 years with the aim of implementation of blood flow volume measurements in clinical assessment of patients with carotid artery disease. There were 303 patients without history of neurologic symptoms included in the examination. The group of 123 healthy volunteers older than 65 years, without comorbidities that may alter cerebral blood flow volume, were examined to determine reference flow volume values in the ICA, ECA, and VA. The flow parameters in this group were compared with the flow in 56 healthy volunteers younger than 65 years. To determine the influence of ICA stenosis on cerebral blood flow volume, the group of 124 patients older than 65 years with asymptomatic ICA stenosis without comorbidities that might influence hemodynamics of blood flow were examined. In all patients, an extensive Doppler ultrasound examination with measurement of blood flow volume in the ICA, ECA, and VA was performed. Cerebral blood flow volume reference values in patients older than 65 years were determined. Gradual decline in cerebral blood flow, caused mainly by the significant reduction of ICA flow volume, was observed in healthy volunteers. A decline in the peak systolic and end-diastolic velocities in the ICA and the peak systolic velocity in the ECA was observed. Two subgroups with ICA stenosis and flow volume changes were identified: patients with compensatory elevation of blood flow volume and those without compensation whose flow volume was lower than reference values. The latter subgroup contained mainly patients with >50% ICA stenosis. Among asymptomatic patients with significant ICA stenosis, there is a subgroup without compensatory elevation of blood flow volume. Those patients may be more vulnerable to cerebral ischemia and featured with increased risk of ischemic stroke.

Pulmonary effects of repeated six-hour normoxic and hyperoxic dives.

This study examines differential effects of immersion, elevated oxygen partial pressure, and exercise on pulmonary function after series of five daily six-hour dives at 130 kPa (1.3 ATA), with 18 hours between dives. Five cohorts of 10 to 14 divers participated. The exposure phases were resting while breathing O2 or air in the water (“wetO2”, “wetAir”) or O2 in the hyperbaric chamber (“dryO2”), and exercise in the water while breathing O2 or air (“wetO2X”, “wetAirX”). Respiratory symptoms were recorded during and after each dive, and pulmonary function (forced flow-volume) was measured twice at baseline before diving, after each dive both immediately and on the following morning, and three days post diving (“Day+3”). The incidences of symptoms and of flow volume changes from baseline greater than normal limits (“ΔFV”) were assessed, as were mean ΔFV. The parameters examined were forced vital capacity (FVC), forced expired volume in 1 second (FEV1), and forced expired flow from 25% to 75% volume expired (FEF25–75). The phases ranked from greatest to least fraction of diver-days with symptoms were wetO2X (56%) > dryO2 (42%) > wetO2 (13%) > [wetAir (2%) or wetAirX (1%)] (p<0.05). FEV1 and FEF25–75 were depressed in the morning following wetO2 and wetO2X and on Day+3 after and wetO2X, but increased immediately following each wetAirX dive. O2 exposures caused symptoms and ΔFV suggestive of pulmonary oxygen toxicity,exacerbated by exercise. Indices of small airway function showed late (17-hour) post-O2 exposure deficits, but, particularly with exercise, improvement was evident early after exposure with or without O2. FEF25–75 and FEV1 remained depressed on Day+3 after wetO2 and wetO2X.

Numerical simulation of the vapour-droplet systems hydrodynamics taking into account particles’ coagulation and fragmentation

The purpose of the work is description of the processes occurring in the liquefied natural gas heater-gasifier having small duration of transition process upon transition to the stationary mode at the flow volume change on the basis of mathematical modeling of the thermo- and hydrodynamics of multiphase mist flows with swirling of the stream.

Coronary blood flow volume change is negatively associated with platelet aggregability in patients with non-obstructive ischemic heart disease who have no anti-platelet agents

BackgroundThrombus formation is one of the main pathogeneses of acute coronary syndrome with atherosclerotic rupture. Previous studies have reported that atherosclerosis increases platelet aggregability and that vascular endothelial dysfunction reflects early change of atherosclerosis. However, the relationship between coronary endothelial dysfunction and platelet reactivity remains unclear. Therefore, in this study, we investigated the relationship between them in non-obstructive ischemic heart disease (IHD) patients. MethodsThree hundred sixty-eight consecutive stable patients with suspected angina presenting non-obstructive coronary arteries (<50% diameter) in coronary angiography were investigated with the intracoronary acetylcholine provocation test and measured adenosine triphosphate-induced coronary flow reserve. Finally, 25 non-obstructive IHD patients who had no anti-platelet agents were assessed for the relationship between coronary blood flow volume (CBFV) change and platelet aggregability as P2Y12 reaction unit (PRU) by VerifyNow P2Y12 assay system. ResultsCBFV change by intracoronary 20 μg/kg per minute acetylcholine provocation showed a significant negative correlation with platelet aggregability as PRU (r = 0.44, P = 0.03). Conversely, there was no significant correlation between PRU and endothelial function as coronary flow reserve. Furthermore, multivariable linear regression analysis indicated that an incremental CBFV change was independently associated with PRU (β = 0.63, P < 0.001) in non-obstructive IHD patients. ConclusionsIn patients with non-obstructive IHD, CBFV change was significantly associated with platelet aggregability, indicating that coronary endothelial dysfunction might mediate higher platelet aggregability.

Ultrasound analysis of a novel therapeutic intervention for neuropathy: intraneural facilitation acute effects on idiopathic and chemotherapy induced peripheral neuropathy

Intraneural Facilitation (INF) is a novel therapy for the treatment of various neuropathic pathologies. INF is an evidence‐based approach which utilizes physical‐therapy‐based “holds” to stretch and relax peripheral associated nerve areas and thus potentially allows for re‐establishment of blood supply (oxygen and nutrients) to damaged nerves.The acute efficacy of INF therapy to treat idiopathic or chemotherapy‐induced neuropathy remains undetermined. Therefore, in a pilot feasibility study, we examined the effects of acute changes by ultrasound assessment of the arterial pulsatility index and volume flow with pre‐ and post‐Intraneural Facilitation Treatment in patients with chemotherapy‐induced neuropathy and idiopathic peripheral neuropathy.PurposeTo determine the acute effect of a novel therapeutic intervention called intraneural facilitation on patients with idiopathic (IPN) and chemotherapy‐induced (CIN) peripheral neuropathies.MethodsThis is a prospective pre‐ and posttest, single group clinical pilot study in an outpatient physical therapy clinic. Participants are patients with peripheral idiopathic or chemotherapy‐induced neuropathy. Outcome measures were assessed with ultrasound measures 1) pulsatility index (PI), which is a measure of the variability of blood velocity in a vessel, equal to the difference between the peak systolic and minimum diastolic velocities divided by the mean velocity during the cardiac cycle, and 2) volume flow (VF), a measure of a cross‐sectional blood vessel area in a time‐averaged velocity.ResultsThere were 38 arterial ultrasound measurements in 13 patients diagnosed with either CIN or IDN for this pilot study. The PI showed significant improvement from pre‐ to post‐treatment in both neuropathy categories, CIN and IDN respectively (p &lt; 0.05). The average total percent change in the 38 arterial measurements of PI was +1.32% and VF was −2.59%. The percent change in PI and VF in patients with IDN was +1.25% and −8.26% and CIN was +1.36% and +0.12%, respectively. Ultrasound measurements of the left radial artery showed a treatment efficacy with a significant change in PI (p = 0.0463).ConclusionThese preliminary pilot outcome results, using ultrasound assessment parameters PI and VF are clinically promising. Intraneural facilitation treatment improves objective PI and VF “markers” in patients with CIN and IDN. Overall, the average percent change of PI showed that there was a significant acute improvement in patients with both CIN and IDN. Greater frequency and chronicity of INF treatment is suggestive to be potentially efficacious in the resolution of the respective neuropathies. These promising pilot patient data suggests the need for further expansive prospective studies to expand a more comprehensive clinical understanding of this new novel treatment called, Intraneural Facilitation Treatment. These studies are currently in progress.Support or Funding InformationDepartmentalThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Analysis of flow patterns on branched endografts for aortic arch aneurysms

Abstract Objective Rupture of aneurysm on the aortic arch leads to significant rates of mortality. Traditional surgical repair is traumatic and may be inappropriate for some patients. Deployment of internally directed side branches provides a feasible alternative, but the hemodynamic implications have not been fully investigated and will be addressed in this study. Method Both patient specific pre- and post-operative conditions are treated here with computational fluid dynamics. Quantitative indicators like volume flow rate, wall shear stress and helicity index are employed. Results Changes in volume flow are generally mild unless an antegrade branch is utilized. Wall shear stress reveals a fluctuating and complex flow pattern between the brachiocephalic and left subclavian artery after graft implantation. Circumferentially averaged oscillatory shear indices at the left common carotid artery are in the range of (0.18, 0.26). Helical flows are observed both before and after surgical repairs, and are measured by spatially integrated helicity and a ‘helicity flow index’. Before surgical implant of grafts, blood flows frequently display a predominant direction of rotation. This feature is typically diminished after the implantation. Conclusion In general, aortic blood flow displayed a higher degree of oscillatory and helical features after internal side branches were deployed. Clinically, oscillatory flows may promote blood clot formation. Furthermore, flow separation points near the outer wall of internal side branches induce fluctuations in pressure and force which might threaten the integrity of the stent graft. To achieve the goal of side branch patency, proper stent orientation is thus critical.

ICP curve morphology and intracranial flow-volume changes: a simultaneous ICP and cine phase contrast MRI study in humans

BackgroundThe intracranial pressure (ICP) curve with its different peaks has been extensively studied, but the exact physiological mechanisms behind its morphology are still not fully understood. Both intracranial volume change (ΔICV) and transmission of the arterial blood pressure have been proposed to shape the ICP curve. This study tested the hypothesis that the ICP curve correlates to intracranial volume changes.MethodsCine phase contrast magnetic resonance imaging (MRI) examinations were performed in neuro-intensive care patients with simultaneous ICP monitoring. The MRI was set to examine cerebral arterial inflow and venous cerebral outflow as well as flow of cerebrospinal fluid over the foramen magnum. The difference in total flow into and out from the cranial cavity (Flowtot) over time provides the ΔICV. The ICP curve was compared to the Flowtot and the ΔICV. Correlations were calculated through linear and logarithmic regression. Student’s t test was used to test the null hypothesis between paired samples.ResultsExcluding the initial ICP wave, P1, the mean R2 for the correlation between the ΔICV and the ICP was 0.75 for the exponential expression, which had a higher correlation than the linear (p = 0.005). The first ICP peaks correlated to the initial peaks of Flowtot with a mean R2 = 0.88.ConclusionThe first part, or the P1, of the ICP curve seems to be created by the first rapid net inflow seen in Flowtot while the rest of the ICP curve seem to correlate to the ΔICV.

The ecohydrological vulnerability of a large inland delta to changing regional streamflows and upstream irrigation expansion

AbstractFuture climate change and anthropogenic interventions can alter historical streamflow conditions and consequently degrade the health and biodiversity of freshwater ecosystems. Future ecohydrological threats, however, are difficult to quantify using the cascade of climate and hydrological models due to various uncertainties involved. This study instead uses a fully bottom‐up approach to evaluate the ecohydrological vulnerability of the Saskatchewan River Delta (SRD), the largest inland delta in North America, to changing streamflow regime and irrigation expansion. An ensemble of perturbed streamflow sequences, along with scenarios of current and expanded irrigation, was generated and fed into a regional water resource system model. Results show that the streamflow regime in the delta is more sensitive to upstream changes in annual flow volume than peak flow timing and/or irrigation expansion. The sensitivity to changes in flow volume, however, may be intensified when combined with changes in peak timing. Shifts in the upstream peak flow timing can alter the magnitude and timing of peak flow to the delta, with prime importance to aquatic biota that are adapted to historical rhythmicity in peak flows and timing. Irrigation expansion decreases the magnitude and frequency of the peak flows, alters the frequency of average and low flows, and slightly shifts the timing of the mean annual peak flow in the SRD. This can lead to isolation of lakes and wetlands from the main stream. Our results highlight the ecohydrological vulnerability of the SRD under potential changing conditions and can assist in proposing adaptation policies to protect this ecosystem.