Mean Blood Flow Research Articles

Reallocation of cutaneous and global blood circulation during sauna bathing through a closed-loop model

ObjectiveSauna bathing (SB) is an important strategy in cardiovascular protection, but there is no mathematical explanation for the reallocation of blood circulation during heat-induced superficial vasodilation. We sought to reveal such reallocation via a simulated hemodynamic model. MethodsA closed-loop cardiovascular model with a series of electrical parameters was constructed. The body surface was divided into seven blocks and each block was modeled by a lumped resistance. These resistances were adjusted to increase skin blood flow (SBF), with the aim of reflecting heat-induced vasodilation during SB. Finally, the blood pressure was compared before and after SB, and the blood flow inside the aorta and visceral arteries were also analyzed. ResultsWith increasing SBF in this model, the systolic, diastolic, and mean blood pressure in the arterial trunk decreased by 13–29, 18–36, and 19–37 mmHg, respectively. Despite the increase in the peak and mean blood flow in the arterial trunk, the diastolic blood flow reversal in the thoracic and abdominal aortas increased significantly. Nevertheless, the blood supply to the heart, liver, stomach, spleen, kidney, and intestine decreased by at least 25%. Moreover, the pulmonary blood flow increased significantly. ConclusionSimulated heat-induced cutaneous vasodilation in this model lowers blood pressure, induces visceral ischemia, and promotes pulmonary circulation, suggesting that the present closed-loop model may be able to describe the effect of sauna bathing on blood circulation. However, the increase of retrograde flow in the aortas found in this model deserves further examination.

Prediction of Fetal Growth Restriction for Fetal Umbilical Arterial/Venous Blood Flow Index Evaluated by Ultrasonic Doppler under Intelligent Algorithm

The empirical wavelet transform (EWT) algorithm was applied in ultrasound to explore the predictive value for fetal growth restriction (FGR) in fetal arteriovenous indexes. 142 pregnant women who received prenatal ultrasonic examination and delivered were selected. They were classified into control group and FGR group. There were 102 patients with normal pregnancy in the control group, and 40 patients with delayed fetal growth in the FGR group. The extended triple collocation (ETC) algorithm was employed to divide the Fourier spectrum of signals adaptively, and the constructed small filter banks were classified into corresponding intervals. The instantaneous frequency was analyzed, and the arterial blood flow indexes of the two groups were compared. The results showed that the time-frequency analysis method under EWT had lower normalization error and higher accuracy. The inner diameter and cross-sectional area of FGR were remarkably smaller than those of the control group, and the differences were statistically significant (P < 0.05). There were no significant differences in mean blood flow and mean blood velocity between the control group and FGR group (P > 0.05). The arterial blood flow parameters of the systolic flow velocity (VS) and the diastolic flow velocity (VD) in the FGR group were notably lower than those in the control group, and the differences were significant (P < 0.05). In conclusion, the frequency principal component extracted by EWT algorithm was less disturbed by noise, which could accurately and effectively evaluate fetal arteriovenous blood flow indexes and predict FGR.

Prognostic properties of the association between the S-100B protein levels and the mean cerebral blood flow velocity in patients diagnosed with severe traumatic brain injury.

Craniocerebral injury (CBI) is tissue damage caused by a sudden mechanical force. CBI can result in neurological, neuropsychological and psychiatric dysfunctions. Currently, the severity of CBI is assessed using the Glasgow Coma Scale, brain perfusion pressure measurements, transcranial Doppler tests and biochemical markers. This study aimed to determine the applicability of the S-100B protein levels and the time-averaged mean maximum cerebral blood flow velocity (Vmean) as a means of predicting the treatment outcomes of CBI in the first 4 days of hospitalization. The results validated the standard reference ranges previously proposed for the concentration of S-100B (0.05-0.23 µg/l) and the mean of cerebral blood flow velocity (30.9 to 74.1 cm/sec). The following stratification scheme was used to predict the success of treatment: Patients with a Glasgow Outcome Scale (GOS) score ≥4 or GOS <4 were stratified into ‘favorable’ and ‘unfavorable’ groups, respectively. The favorable group showed relatively constant levels of the S-100B protein close to the normal range and exhibited an increase in Vmean, but this was still within the normal range. The unfavorable group exhibited a high level of S-100B protein and increased Vmean outside of the normal ranges. The changes in the levels of S-100B in the unfavorable and favorable groups were -0.03 and -0.006 mg/l/h, respectively. Furthermore, the rate of decrease in the Vmean value in the unfavorable and favorable groups were -0.26 and -0.18 cm/sec/h, respectively. This study showed that constant levels of S-100B protein, even slightly above the normal range, associated with an increase in Vmean was indicative of a positive therapeutic outcome. However, additional research is required to obtain the appropriate statistical strength required for clinical practice.

Abstract 482: Early Reduction of Blood Flow in Rabbit Jugular Vein-Carotid Artery Bypass Grafts is not Caused by Anastomotic Stenosis

Background: Obstructed arteries are often treated by surgical implantation of venous bypass grafts. Vein grafts can fail for many reasons, including thrombosis, atherosclerosis, or anastomotic stenoses (narrowings where the grafts connect to the artery). In a previous study aimed at developing a hyperlipidemic rabbit model of vein-graft atherosclerosis for testing gene therapy, vein grafts used to bypass carotid arteries were widely patent. However, vein graft blood flow decreased by a mean of 5.6 mL/minute (~23%) between 8 and 16 wks after grafting, with flow at 16 wks reduced to &lt;60% of flow in an unoperated carotid artery. We hypothesized that decreased flow was caused by anastomotic stenoses, raising concern that this might lead to graft occlusion, precluding use of the model to test gene therapy for atherosclerosis. Methods: We designed an experiment to test whether anastomotic stenoses were present and—if so—whether the stenoses were the cause of decreased blood flow. In a new set of grafted veins, we harvested the anastomoses, embedded, sectioned and stained them, and measured percent stenosis using computer-assisted image analysis. Percent stenosis was calculated by dividing intimal area by the stenosis-free lumen area (calculated from the length of the IEL, assuming circular geometry in vivo). We measured stenoses in both anastomoses of 22 patent vein grafts, harvested from 14 hyperlipidemic rabbits (44 total anastomoses). Blood flow (mL/min) in each vein graft was measured with a flow meter at 4 wks after grafting and again at 16 wks (at harvest). Results: The mean blood flow at the 4 wks measurement was 51 mL/minute (range: 28 to 90) and 36 mL/minute (range: 21 to 53) at the harvest measurement. The calculated mean change in blood flow was –16 mL/minute (range: –55 to +14). The mean anastomotic stenosis was 39% (range: 2.3% to 89%). Using Spearman’s rank-order correlation test, we found that percentage stenosis did not correlate with the change in blood flow (r=0.059; P=0.8). Conclusions: Decreased blood flow in our vein graft model is likely not caused by anastomotic stenoses. Other explanations, such as decreased cardiac output or increased downstream vascular resistance (caused by cerebral atherosclerosis or microemboli) should be considered.

Effects of Beta‐Blockers on Thermal and Cardiovascular Strain of Adults With Coronary Artery Disease During Extreme Heat Events

IntroductionExtreme heat is associated with a greater risk of adverse cardiovascular events, especially in people with cardiovascular disease. Many patients with cardiovascular disease are prescribed beta‐blockers. Some research suggests that in young healthy adults, cardio‐selective beta‐blockers may alter heat loss capacity. However, the effects of beta‐blockers on temperature regulation in older adults during an extreme heat event are unknown. The objective of this study was to compare thermal and cardiovascular responses during simulated extreme heat events between older adults with coronary artery disease (CAD) who use and do not use beta‐blockers. It was hypothesised that the increase in heart rate and skin blood flow would be smaller in CAD patients who use beta‐blockers compared to those who do not use beta‐blockers.Method25 older adults (23 males/2 females) with stable CAD, 18 taking cardio‐selective beta‐blockers (BB: 66±8 y; 85.7±13.3 kg; 28.0±4.6 kg/m2) and 7 not taking beta‐blockers (NBB: 66±7 y; 77.1±14.6 kg; 26.1±3.9 kg/m2), were exposed to two 3‐hour simulated extreme heat events; one hot and humid (38°C, 60% relative humidity) and one hot and dry (45°C, 10% relative humidity). Rectal and mean skin temperatures, heart rate, and skin blood flow were continuously recorded. Whole body sweat losses were calculated from changes in nude body weight.ResultsAt the end of the 3‐h hot and humid heat exposure, relative to pre‐exposure baseline the change in heart rate (BB: +7±5 bpm; NBB: +11±9 bpm, p=0.20), rectal (BB: +0.57±0.27°C; NBB: +0.60±0.31°C, p=0.76) and mean skin (BB: +5.1±1.2°C; NBB: +5.1±1.1°C, P=0.91) temperatures, and whole body sweat losses (BB: 771±480 g; NBB: 798±172 g, p=0.88) did not differ between groups. The change in skin blood flow from baseline was greater in the NBB (+32±23 arbitrary units) compared to the BB (+9±7 arbitrary units; p=0.01) group. At the end of the 3‐h hot and dry heat exposure, the increase in heart rate (BB: +9±8 bpm; NBB: +9±5 bpm, p=0.93), rectal (BB: +0.61±0.40°C; NBB: +0.62±0.22°C, p=0.91) and mean skin (BB: +5.9±0.9°C; NBB: +5.7±1.3°C; p=0.79) temperatures, whole body sweat losses (BB: 1252±174 g; NBB: 1207±169, p=0.56) and skin blood flow (BB: +26±22 arbitrary units; NBB: +26±39 arbitrary units; p=0.98) from baseline did not differ between groups.ConclusionOur preliminary evidence indicates that cardio‐selective beta‐blocker use does not alter thermal or cardiovascular strain in adults with stable coronary artery disease during simulated hot and humid or hot and dry extreme heat events.

A doppler ultrasonographic observation of interventional postural alterations on shear rates in peripheral arteries

Introduction and Aim: Drastic life style changes had resulted in increased reports of morbid atherosclerosis in young adults which is potentially a serious inflammatory condition which causes arteries to become harder and blocked with lipid accumulation known as plaques or atheroma. In the present study, effect of changes in posture on the resting shear rate (SR) was studied in arteries of both extremities. Materials and Methods: A cross sectional observational doppler ultrasound study was done in 30 healthy subjects, who satisfied a pre-set inclusion and exclusion criteria. The mean blood flow velocity (BV) and diameter were measured for both brachial arteries and femoral arteries in supine, sitting with leg fully extended, sitting with leg flexed at 90o, standing with and without slight head tilting of 10o postures after resting the subjects for 10 minutes in between each posture. The SR in various postures were calculated and tabulated. The data was statistically analysed using independent ‘t’ test and one-way ANOVA. Post Hoc test was applied for analysing statistical significance of SR in between postures. Results: The femoral artery showed significantly lower SR (P&lt;0.001) in all the postures studied when compared to brachial artery. On comparing posture within brachial and femoral artery by applying one-way ANOVA with Post Hoc test, only femoral showed significant difference in SR between postures. Conclusion: The postural effect in SR of arteries in lower limb may lead to alterations in the endothelium of arteries resulting in increased atherogenicity as compared to upper limb arteries.

Genesis of Antibiotic Resistance (AR) LXXVIII: Turbulence Modeling of Hemodynamics in Simplified Severe Sepsis Protocol‐2 (SSSP‐2)‐NCT01663701(ERP‐EGDT): Correlation of time (&amp; fluid bolus) dependent pressure drop in boundary layer separation with adverse pressure gradient (APG) in tandem with exacerbated in‐hospital mortality(ihm)

The objective is to identify the underlying hemodynamic alteration in usual care group registered with 5 patients @ 100% ihm; vs the sepsis protocol cohort registered with 11 patients @ 90.05% ihmwith a median hospital stay of 5 days; GCS 3‐8(SAPS3≥56, (Ref: Fig 3) NCT01663701(PMID: 28973227). Cause for Concern: The pivotal clinical indices such as, i. antibiogram, ii.drug resistance index(DRI), iii.resistance map(RM), iv.antibiotic resistance footprint (ARF), v.AR stewardship data, and vi. Global Antimicrobial Resistance and Use Surveillance System (GLASS) data, for the entire patients’ cohorts before and after admitting to ED as a part of baseline characteristics, not presented. Rationale: Based on the aforesaid factor, it is inferred that patients in any given ERP‐EGDT, are: i. pre‐disposed to unknown level of infectious diseases burden with AR clinical persister(s)(ARClPrs); ii. activation of leucocytes, platelets, and erythrocytes forming LPE aggregates; iii. unknown extent of laceration in the precapillary arterioles, and post‐capillary venules, and iv. deposition of LPE aggregates on the pre‐capillary/post‐capillary vessels, w/o intravascular (loss of glycocalyx), in the cerebral/coronary/pulmonary/hepatic pre‐capillary arterioles, Fig 3.1 to 3.3; Fig 3.4, Derived rheological factors based on the data from Table 2: elements of sepsis resuscitation p1238; Fig 3: Risk of In‐hospital Mortality, p1239; predicted to be PI &lt;1.05%, SpO2≦95%, PaO2 of 55 mmHg, SaO2&lt;90%, SvO2&lt;90%, StO2 below normal, DO2I below normal range, FiO2 &lt;0.21(21%), PaCO2&lt; 38 – 42 mmHg and PaO2/FiO2 &lt;200mmHg. Derivation inclusive of CC, MCC (major complication or comorbidity), DDx:Pulmonary Edema, hypoxemia, tachypnea, and respiratory failure. GCS 3‐8: Coma Grade IV‐ unconscious, deep sleep, vestibular ocular reflex(VOR) negative, craniocaudally loss of brainstem reflexes, no reaction to pain, flabby tone, pupil dilated &amp; fixed). Geometry: Blood flow network and mother‐daughters branching several generation of arterioles (or venules) with specific mean blood flow velocity (Vn), arbitrary generation (g) where rn = vessel radius of generation(n), r1 and v1 = radius, Fig 3.4 (p90 ISBN13‐978‐0128024089). Hypothesis &amp; Governing Equation: eq: 3.2; eq 3.3; eq 3.4; Poiseuille eq (to determine and analyze the cause &amp; effect relationship of flow pressure drop in a long cylindrical pipe/pre‐capillary vessels): DP=8mLQ /p R4 where DP = pressure difference between the two ends, m = dynamic viscosity, L=length of pipe, Q = volumetric flow rate, p = the dynamic viscosity, R = pipe radius (http://hyperphysics.phy‐astr.gsu.edu/hbase/ppois.html). Prospect: Simulation efforts are in progress to determine the sequence of fluid flow within the time scale of &lt;0hrÛEDÜ120hrs&gt;, pseudo‐plastic fluidÜdilatantÜBingham plasticÜ Hershel‐BuckleyÜ ThixotropicÜ Rheopectic)and its role in physiological (capillary) shunt augmented ihm.

Effect of Arterial Stiffness and Cerebral Pulsatility on Hippocampal Tissue Integrity in Healthy Adults

Elevated large elastic artery (i.e. aorta and common carotid) stiffness has emerged as a risk factor of cognitive impairment in older adults. Stiffening of these arteries leads to increased pulsatile energy transmission into the brain, which may result in structural damage to neuronal tissue, and potentially precipitate cognitive decline. In this regard, changes to microstructural integrity of the hippocampus (HC), a brain structure essential for memory encoding, may reflect the impact of age‐related increases in arterial stiffness and pulsatile blood flow through the middle cerebral artery (MCA). Therefore, the purpose of this study was to determine whether large elastic artery stiffness and associated pulsatile hemodynamics are related with HC integrity in healthy adults across the lifespan. We included 25 participants (16M/9F, age: 44±16 y; age range: 22‐69 y; BMI: 27±5 kg/m2; BP: 115±11/71±10 mmHg) in this study. Aortic stiffness was assessed as carotid‐femoral pulse wave velocity (PWV) using applanation tonometry (AtCor Medical, Sydney, Australia). Common carotid artery (CCA) stiffness was measured using duplex ultrasound (Logiq e, GE Healthcare, Chicago, IL) and analyzed with an offline wall‐tracking software (Cardiovascular Suite, Pisa, Italy). CCA blood pressures were acquired from applanation tonometry. Transcranial Doppler ultrasound was used to measure basal mean blood flow velocity of the MCA (MCAv) from which Gosling’s pulsatility index (PI) was calculated as the difference between peak systolic MCAv and end‐diastolic MCAv over mean MCAv. HC tissue integrity was measured using magnetic resonance elastography (MRE), which was acquired using a Siemens 3T Prisma MRI scanner coupled with shear waves generated via a pneumatic actuator (Resoundant, Rochester, MN) at 50 Hz. Bilateral HC stiffness (µ) and HC damping ratio (ξ) were estimated from MRE displacement data using a nonlinear inversion algorithm. A correlation matrix was used to determine if arterial stiffness, vascular hemodynamics, and other lifestyle factors (e.g., age, sex, BMI) were related with HC integrity. BMI (r=‐0.40, p=0.048), CCA pulse pressure (PP) (r=‐0.61, p=0.001), and MCAv PI (r=‐0.48, p=0.01) were associated with HC µ while age (r=0.66, p=0.0004), BMI (r=0.45, p=0.02), SBP (r=0.52, p= 0.008), aortic PWV (r=0.65, p=0.0004), and CCA stiffness (r=0.60, p=0.002) were associated with HC ξ. Next, multiple linear regressions were performed to determine the independent associations among arterial stiffness, vascular hemodynamics of interest, and HC integrity while correcting for age and BMI. HC µ remained significantly associated with CCA PP (β=‐0.52, p=0.03) and was trending towards negative association with MCAv PI (β=‐0.37, p=0.06). There were no significant independent associations among the variables of interest and HC ξ, however, together these variables significantly explained variance in HC ξ (R2=0.37, p=0.03). Our results suggest increased pulsatile pressure through the carotid artery along with elevated cerebral pulsatility negatively impacts HC tissue integrity. Future studies should consider how our current findings affect functional outcomes like memory and age‐related neurological conditions.

Limb Hemodynamic Responses to a Single Bout of Inspiratory Muscle Strength Training

BackgroundInspiratory muscle strength training (IMST) has been shown to bring about improvements in respiratory muscle strength and reductions in blood pressure after 6 weeks of daily high intensity training. However, there has been little investigation into the effects of IMST on limb blood flow, and it is unclear how hemodynamics are altered within a single bout of training.PurposeTo investigate the acute effects of one session of either low or high intensity IMST on blood flow in the upper and lower limbs.MethodsParticipants (n=7, 57% female) aged 20 to 47 years completed two randomized laboratory visits wherein resting blood flow was measured via duplex Doppler ultrasound at the left brachial and popliteal arteries. Following baseline measures, participants' maximal inspiratory pressure (PImax) was measured using a PowerBreathe K3 device. Participants performed one session (30 breaths) of IMST at either 15% or 75% of their PImax, and blood flow was measured again at each artery for five breaths during the final ten breaths of the training. At their second visit, subjects performed whichever training level had yet to be completed and blood flow was assessed as described above.ResultsMean blood flow at the brachial artery appeared reduced during both 15% (p=0.070) and 75% training (p=0.078), which may be attributed to a significant increase in retrograde blood flow in both cases (p=0.014 and p=0.037, respectively). This increase in retrograde blood flow tended to be greater during the 75% training (p=0.066). Popliteal artery blood flow showed similar trends to brachial artery blood flow.ConclusionsWhile IMST appears to reduce brachial artery mean blood flow during a single training session, this may be due to alterations in retrograde blood flow, which tended to increase in an intensity‐dependent manner. Further investigation into the chronic hemodynamic effects of IMST is warranted.

Evaluation of the reproducibility and confounders of fair ASL placenta perfusion measurement in normal pregnancies

Arterial spin labeling (ASL) is a very promising non-invasive MRI technique that quantifies placental perfusion using arterial blood water as an endogenous tracer, but lacks reproducibility and standardization, which limits its use in clinical practice. The objective was to standardize and identify confounders of FAIR ASL in placental perfusion estimation. This was a prospective study at Necker Hospital ( NCT04142606 ). Fetal weight estimation and Doppler measurements were performed, followed by MRI on a 1.5 T scanner. A T2-weighted axial FIESTA placenta-centered slice was performed as a reference. Perfusion data were acquired with a 10 mm axial single slice FAIR-SSFSE, repeated 3 times with variable selective inversion thickness (3, 5 and 7 cm). To assess reproducibility, the sequences were performed twice and perfusion was measured on the whole placenta and in 4 regions of interest (ROI) by two operators. We also studied the impact of maternal age, gestational age at examination or placental location on blood flow measurements. Sixty-two patients with normal pregnancy were included. The respective mean blood flow for the 3, 5 and 7-cm-thick inversion was 238.3 ± 68.0 mL/100 g/min, 156.4 ± 46.5 mL/100 g/min and 121.6 ± 39.7 mL/100 g/min respectively (ANOVA, P < 0.01) this demonstrates the importance of the methodology in this evaluation. The thicker section appeared to be more representative of placental perfusion in agreement with data in the literature. However we did not observe a significant difference when averaging the perfusion of the 4 ROI or the whole placenta ( P = 0.21, P = 0.56 and P = 0.85 respectively). The sequences were repeated twice in 10 patients and were reproducible. There was no significant difference according to maternal age, gestational age at examination and placental location (anterior or posterior). This study evaluated the reproducibility of FAIR ASL for measuring placental perfusion and showed that the selective slab inversion thickness has a significant impact on blood flow measurements. Other potential confounders need to be investigated to enable the application of FAIR ASL in clinical practice. A potential future application of ASL would be to detect placental insufficiency.

Leptin Enhances Nitric Oxide Production and Decreases Blood Flow in Rat Skeletal Muscle

Objective: There are a few studies related to nitric oxide (NO) and leptin interaction in the regulation of physiological events in skeletal muscle. Therefore, the aim of the present study is to investigate the interaction of leptin and NO in response to blood flow and nitric oxide synthase (NOS) distribution on rat skeletal muscle. Materials and Methods: Twenty-four adult-male Wistar albino rats were divided into 4 groups: control (C), Leptin (LP) (50 μg/kg), L-NG-nitroarginine methyl ester (LN) (a non-specific nitric oxide synthase inhibitor, 10 mg/kg,) and L-NAME+Leptin (LN+LP) administrated groups. Drugs were administered via the right jugular vein. Hemodynamic parameters: mean arterial pressure, heart rate and blood flow were recorded during the experiment and at the end blood samples for biochemical analyses of leptin and nitrite/nitrate levels and gastrocnemius muscle tissues from the right hindlimb for NOS distribution were taken. Results: Leptin infusion after L-NAME administration significantly decreased heart rate and blood flow (p&lt;0.05, p&lt;0.001). In addition, there was no change in the mean arterial pressure in the leptin group and leptin-administered L-NAME group. Leptin levels were the highest in the LP+LN group (p&lt;0.01). Decreased nitrate/nitrate levels with L-NAME administration (p&lt;0.01 vs C) reached control values by leptin infusion. Both endothelial NOS (eNOS) and neuronal NOS (nNOS) distributions were observed in the skeletal muscle cells of the leptin group. Conclusion: Although NO synthesis is inhibited by L-NAME, it is concluded that leptin partially enhances NO production and leptin uses NO as a mediator in its physiological effects.

The Effect of 12-Week Treatment with Intermittent Negative Pressure on Blood Flow Velocity and Flowmotion, Measured with a Novel Doppler Device (Earlybird). Secondary Outcomes from a Randomized Sham-Controlled Trial in Patients with Peripheral Arterial Disease

Treatment with intermittent negative pressure (INP) is proposed as an adjunct to standard care in patients with peripheral arterial disease (PAD). The aims of this study were to evaluate the applicability of a novel ultrasound Dopplerdevice (earlybird) to assess blood flow characteristics in patients with PAD during a treatment session with INP, and whether certain flowproperties could determine who could benefit from INP treatment. Secondary outcomes of data from a randomized sham-controlled trial were explored. Patients were randomized to 12weeks of treatment with 40mm Hg or 10mm Hg INP, for one hour twice daily. Earlybird blood flow velocity recordings were made before and after the 12-week treatmentperiod and consists of a 5-min recording in rest, 3-min during INP treatment and 5-min recording after ended INP test-treatment. Mean blood flow velocity (vmean), relative changes in flow and frequency spectrum by Fourier-transform of the respective bandwidths of endothelial, sympathetic, and myogenic functions, were analyzed for the different series of blood flow measurements. In total, 62 patients were eligible for analysis, where 32 patients were treated with 40mm Hg INP. The acquired recordings were of good quality and were used for descriptive analyses of flow characteristics. An immediate increase in vmean during the negative pressure periods of the INP test-treatment was observed in the 40mm Hg INP treatment group at both pre- and post-test. There was a significant difference between the treatment groups, with a difference between the medians of 13.7 (P<0.001) at pre-test and 10.7 (P<0.001) at posttest. This finding was confirmed with spectrum analysis by Fourier-transform of the bandwidth corresponding to INP treatment. The change in amplitude corresponding to myogenic function after 12-weeks of treatment, was significantly different in favor of the 40mm Hg INP treatment group. We were not able to detect the specific flow characteristics indicating who would benefit INP-treatment. Earlybird is an applicable tool for assessing blood flow velocity in patients with PAD. Analysis of the flow velocity recordings shows that INP induces an immediate increase in blood flow velocities during INP. The positive effects of INP may be attributed to recruitment of arterioles, and thereby, increasing blood flow. In these analyses, no flow characteristics were determined which could predict who would benefit INP treatment.

Dynamic Changes on Video-capillaroscopy and Potential Microsurgical Application: Temperature and Skin Surface Readings.

Summary:Video-capillaroscopy is being explored as a potential tool for microsurgical flap monitoring. A detailed examination of the effect of temperature on capillary changes using video-capillaroscopy is yet to be investigated. We analyzed the video-capillaroscopy findings on different skin areas often used for flap harvest at normal body temperatures and at lower temperatures. Skin capillaries at the lateral thigh, anterior forearm, mid-axillary line, abdomen, and fingertips were observed using video-capillaroscopy in 20 healthy Japanese individuals. Further, ImageJ software was used to measure the blood vessel area and blood flow velocity, and comparisons were drawn between normal body temperature and lower body temperature states. All measures of blood vessel area and average blood flow velocity for the different anatomical regions were significantly different before and after cooling (P < 0.001). The mean reduction rate of the vessel area was significantly different among anatomic regions (P < 0.001). Post-hoc analysis revealed a significant difference in the vessel area reduction rate between anatomic areas (P < 0.05); except when comparing the thigh versus finger, the forearm versus abdomen, and the mid-axillary line versus abdomen. The mean blood flow velocity was significantly different among anatomic regions (P < 0.001). Post-hoc analysis revealed a significant difference between the thigh and forearm (P = 0.009), the forearm and fingertip (P = 0.001), and the abdomen and fingertip (P = 0.004). Decreasing the skin temperature resulted in a significant vasoconstriction and reduction in capillary flow velocity. It is imperative to keep the monitored area warm during video-capillaroscopy assessment to avoid false diagnosis of vascular occlusion.

Transcranial Doppler sonography and the effect of haematopoietic stem cell transplantation in sickle cell disease

BackgroundSickle cell disease (SCD) is one of the most prevalent monogenetic diseases worldwide and one of the most serious complications is stroke. Transcranial Doppler (TCD) demonstrated to be highly predictive for an imminent stroke by measuring blood flow velocities in the basal cerebral arteries. Currently, the only curative therapy for SCD is hematopoietic stem cell transplantation (HSCT). The aim of this study is to verify the correlation between blood flow velocities and stroke including the effect of HSCT.MethodsIn our retrospective single-center study a total of 26 sickle cell patients (HbSS, HbSß+-thalassemia, HbSSα-thalassemia minima, HbSSα-thalassemia minor and HbSC) were analyzed between 2010 and 2016. The highest time averaged maximum mean blood flow velocity (TAMMV) measured was documented and evaluated with respect to SCD genotype and effect of HSCT. Acute and symptomatic as well as silent strokes were recorded as separate parameters.ResultsIn our study, ten patients had normal blood flow velocities before HSCT (six HbSS and four HbSß+-thalassemia patients) and 13 patients presented with abnormal TCD (eight HbSS, three HbSSα-thalassemia minima, one HbSSα-thalassemia minor and one HbSC). Thirteen of 26 study participants (ten HbSS and three HbSß+-thalassemia patients) received HSCT. In two patients, TAMMV in basal cerebral arteries remained “normal”, in one they remained conditional and in one TAMMV was reduced to normal. Four of 26 study participants (15.4%), including all patients with HbSS genotype, presented with a stroke, but none had “abnormal” TAMMV with TCD performed after the onset of stroke in each case. At the time we performed the TCD, the patients had already suffered the stroke.ConclusionIn our study, none of the patients with stroke displayed abnormal blood flow velocities in TCD. Yet, HSCT at this stage of the disease still had a positive effect on TAMMV. Further studies are needed whether this effect converts into reduced stroke risk at all or only selected SCD patients undergoing HSCT.

Cerebrovascular changes in neuro-Behcet's disease and neuropsychiatric lupus by transcranial Doppler ultrasonography and magnetic resonance imaging

IntroductionTranscranial Doppler ultrasonography (TCD) is a technique that allows measurement of blood flow from the basal intracerebral vessels. It is relatively inexpensive, non-invasive, can be performed at the bedside, and allows monitoring in acute emergency settings and for prolonged periods with a high temporal resolution, making it ideal for studying the haemodynamics within the intracranial arteries in neuro-Behcet's disease (NBD) and neuro-psychiatric lupus (NPSLE). Our aim was to assess the cerebral haemodynamic patterns in patients with NBD and NPSLE using TCD, while brain lesions were examined using magnetic resonance imaging (MRI). Material and methodsCase–control prospective study of 30 neuro-Behcet's disease patients, 25 neuro-psychiatric lupus patients and 26 healthy age-matched volunteers. All patients and healthy controls were examined by TCD. Only the groups of patients underwent cranial magnetic resonance imaging (MRI). ResultsTranscranial Doppler (TCD) values for middle cerebral artery (MCA), anterior cerebral artery (ACA), posterior cerebral artery (PCA), vertebral artery (VA) and basilar artery (BA) in NBD, NPSLE and control groups were measured. The results showed that there was a significant decrease in mean blood flow velocities in all the arteries examined in NBD and NPSLE patients. There was also a significant increase in the pulsatile index of PCA, VA and BA between NBD and NPSLE patients. The same results were obtained when comparing NBD versus controls. However, there was no significant difference between the NPSLE patients and the control group. The MRI lesions described were parenchymal lesions in 14 patients (46.7%), and vascular lesions in 4 patients (13.3%). Vascular lesions co-existed with parenchymal lesions (mixed lesion). Parenchymal lesions were in white matter (40%), thalamus (26.7%), brain stem (26.7%) and cerebellum (20%). While, in NPSLE, 23 patients were normal (92%) and only two patients had a vascular lesion (8%). ConclusionThere was a significant decrease in mean blood flow and a significant increase in the pulsatile index among both NBD and NPSLE patients, according to the TCD values.

In vivo assessment of hypertensive nephrosclerosis using ultrasound localization microscopy.

As a typical chronic kidney disease (CKD), hypertensive nephrosclerosis (HN) is a common syndrome of hypertension, characterized by chronic kidney microvascular damage. Early diagnosis of microvascular damage using conventional ultrasound imaging encounters challenges in sensitivity and specificity owing to the inherent diffraction limit. Ultrasound localization microscopy (ULM) has been developed to obtain microvasculature and microvascular hemodynamics within the kidney, and would be a promising tool for the early diagnosis of CKD. In this study, the advantage of quantitative indexes obtained by using ULM (mean arterial blood flow speeds of different segments of interlobular arteries) over indexes obtained using conventional clinical serum (β2-microglobulin, serum urea nitrogen, and creatinine) and urine (24-h urine volume and urine protein) tests and ultrasound Doppler imaging (peak systolic velocity [PSV], end-diastolic velocity [EDV], and resistance index [RI]) and contrast-enhanced ultrasound imaging (CEUS; rise time [RT], peak intensity [IMAX], mean transit time [mTT], and area under the time-intensity curve [AUC]) for early diagnosis of HN were investigated. Examinations were carried out on six spontaneously hypertensive rats (SHR) and five normal Wistar-Kyoto (WKY) rats at the age of 10weeks. The experimental results show that the indicators derived from conventional clinical inspections (serum and urine tests) and ultrasound imaging (PSV, EDV, RI, RT, IMAX, mTT, and AUC) do not show significant difference between hypertensive and healthy rats (p>0.05), while the TTP of the SHR group (28.52 ± 5.52 s) derived from CEUS is significantly higher than that of the WKY group (18.68 ± 7.32 s; p<0.05). The mean blood flow speed in interlobular artery of SHR (12.47 ± 1.06mm/s) derived from ULM is significantly higher than that of WKY rats (10.13 ± 1.17mm/s; p<0.01). The advantages of ULM over conventional clinical inspections and ultrasound imaging methods for early diagnosis of HN were validated. The quantitative results show that ULM can effectively diagnose HN at the early stage by detecting the blood flow speed changes of interlobular arteries. ULM may promise a reliable technique for early diagnosis of HN in the future.

Left ventricular four-dimensional blood flow distribution, energetics, and vorticity in chronic myocardial infarction patients with/without left ventricular thrombus

BackgroundLeft ventricular thrombus (LVT) formation is a frequent and serious complication of myocardial infarction (MI). How global LV flow characteristics are related to this phenomenon is yet uncertain. In this study, we investigated LV flow differences using 4D flow cardiovascular magnetic resonance (CMR) between chronic MI patients with LVT [MI-LVT(+)] and without LVT [MI-LVT(-)], and healthy controls. MethodsIn this prospective cohort study, the 4D flow CMR data were acquired in 19 chronic MI patients (MI-LVT(+), n = 9 and MI-LVT(-), n = 10) and 9 age-matched controls. All included subjects were in sinus rhythm. The following LV flow parameters were obtained: LV flow components (direct, retained, delayed, residual), mean and peak kinetic energy (KE) values (indexed to instantaneous LV volume), mean and peak vorticity values, and diastolic vortex ring properties (position, orientation, shape). ResultsThe MI patients demonstrated a significantly larger amount of delayed and residual flow, and a smaller amount of direct flow compared to controls (p = 0.02, p = 0.03, and p < 0.001, respectively). The MI-LVT(+) patients demonstrated numerically increased residual flow and reduced retained and direct flow in comparison to MI-LVT(-) patients. Systolic mean and peak LV blood flow KE values were significantly lower in MI patients compared to controls (p = 0.04, p = 0.03, respectively). Overall, the mean and peak LV vorticity values were significantly lower in MI patients compared to controls. The mean and peak systolic vorticity at the basal level were significantly higher in MI-LVT(+) than in MI-LVT(-) patients (p < 0.01, for both). The vortex ring core during E-wave in MI-LVT(+) group was located in a less tilted orientation to the LV compared to MI-LVT(-) group (p < 0.01). ConclusionsChronic MI patients with LVT express a different distribution of LV flow components, irregular vorticity vector fields, and altered diastolic vortex ring geometric properties as assessed by 4D flow CMR. Larger prospective studies are warranted to further evaluate the significance of these initial observations.

Impact of habitual sedentary patterns on popliteal artery endothelial-dependent vasodilation in healthy adults.

Introduction:Acute, laboratory-based bouts of prolonged sitting attenuate lower-limb arterial endothelial-dependent vasodilation. However, the impact of habitual sedentary patterns on popliteal artery endothelial health is unclear. We tested the hypothesis that greater habitual total sedentary time, more time spent in prolonged sedentary bouts, and fewer sedentary breaks would be associated with worse popliteal flow-mediated dilation (FMD) responses.Methods:This cross-sectional study used 98 healthy participants (19–77 years, 53 females) that wore an activPAL monitor on the thigh for 6.4 ± 0.8 days to objectively measure sedentary activity and completed a popliteal ultrasound assessment to determine FMD. Both relative (%baseline diameter) and absolute (mm) FMD were calculated. Using bivariate correlation and multiple regression analyses, we examined if there were relationships between sedentary outcomes and FMD while statistically controlling for any potential confounders.Results:In the multiple regression model, age (p = 0.006, β = −0.030, 95% CI = −0.051, −0.009) and total time in sedentary bouts > 1 hour (p = 0.031, β = −0.005, 95% CI = −0.009, −0.001) were independent predictors of relative FMD. Age (β = −0.002, 95% CI = −0.003, −0.001), mean blood flow (β = 0.013, 95% CI = 0.002, 0.024), moderate-intensity physical activity (β = 155.9E−5, 95% CI = 22.4E−5, 289.4E−5), sedentary breaks (β = 0.036, 95% CI = 0.007, 0.066), and total time spent in sedentary bouts > 1 hour (β = −25.02E−5, 95% CI = −47.67E−5, −2.378E−5) were predictors of absolute FMD (all, p < 0.047). All independent outcomes remained significant after partially controlling for all other predictor variables (all, p < 0.031).Conclusions:Habitual prolonged sedentary bouts and sedentary breaks, but not total sedentary time, were predictors of popliteal endothelial-dependent vasodilatory function. The patterns by which sedentary time is accumulated may be more important than the total sedentary time on lower-limb arterial health.

Alteration in cerebral blood flow, kynurenines with respect to mood profile in freshly recruited armed forces personnel

The present study is conducted to understand the association of mood profile with the kynurenine pathway (KP) metabolites, and cerebral hemodynamics in freshly recruited central armed forces personnel. Profile of Mood States questionnaire was utilized to assess mood profile, and Total Mood Disturbance (TMD) score was calculated. Transcranial Doppler was used to record blood flow velocity bilaterally of the middle cerebral artery. Chromatographic profile of the kynurenine metabolites was obtained in serum. Further, personnel were stratified according to sociodemographic variables (gender, age and diet) to observe the changes in their KP metabolic status. An activation of the kynurenic acid branch of the KP and the reduction in the mean blood flow velocity, and an increase in Gosling pulsatility index (PI) were observed in females having high TMD score. On gender comparative analysis, kynurenine metabolites of quinolinic acid branch and serotonin were significantly high in males. In males, with increase in age, a significant increase in the quinolinic acid branch of the KP was observed. Furthermore, a significant difference in level metabolites of the KP among the vegetarian and non-vegetarian groups was also observed. In conclusion we observed that increased TMD score was associated with cerebral hypoperfusion and higher vascular resistance along with activation of the KP. Our findings highlighted the importance of multi-facet brain function to showcase the close interaction of various dimensionalities and true picture of the assessee.

Antioxidant Associated Antihypertensive Performance of Purified Gambir (Uncaria gambir Roxb.) on Prednisone Salt-Induced Hypertensive Rats

Introduction: Purified gambier (Uncaria gambir Roxb.) is potential for treating hypertension based on its antioxidant bioactivity. In this study, we investigated the antihypertensive performances of purified gambier on hypertensive rats and the correlation with its antioxidant activity. Methods: Rats (2-3 months old and the bodyweight of 200-250 g) were divided into five groups. Groups 1, 2, and 3 were treated orally with water suspension of purified gambier at doses of 2.5; 5; and 10 mg/kg BW once a day for 14 days, group 4 and 5 were acted as positive control (treated with vehicle) and captopril treated group (comparison) respectively. The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), heart rate (HR), blood flow (BF) and blood volume (BV) were recorded once a day before and 1,3,7 and 14 days after commencement. The blood was taken before and at the end of recording for the plasma NO measurement. Two-way ANOVA was used to analyze the changes of those parameters, except for plasma NO analyzes by one-way ANOVA, followed by Duncan multirange test (95% confidence interval). Results: The study showed that significant antihypertensive effects (p&lt;0.05), influenced by doses and gambier administration duration. The plasma NO of animals was increased after administration of purified gambier (p&lt;0.05), although there was no significant difference in plasma NO in doses variation. Conclusion: These indicated that purified gambier proceed antioxidant associated antihypertensive effects at doses of 2.5 – 10 mg/kg BW when administered for 14 days on the salt-prednisone induced hypertensive rats.&#x0D; KEYWORDS: antioxidant, antihypertensive, purified gambier, Uncaria gambir Roxb., salt-prednisone induced, hypertension rat