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Pulse wave attenuation characteristics reflect compliance and resistance properties of the vessel wall as well as initial pulse generation factors. Recently, it has become possible to measure and map the retinal vessel wall pulse wave amplitudes. Predictable pulse wave amplitude distribution may allow inferences to be made concerning vascular compliance and resistance. Twenty-eight eyes from sixteen subjects (8 male and 8 female) were examined using modified retinal photoplethysmography with simultaneous ophthalmodynamometry. This allowed the assessment of vessel wall pulsation amplitudes under a dynamic range of intraocular pressures. Pulse amplitudes were calculated using harmonic regression analysis. The pulse wave attenuation was measured under different ranges of ophthalmodynamometric force (ODF) as a function of distance along the vessel (VDist), which in turn was calculated in disc diameters (DD) from the center of the optic disc. A linear mixed-effects model with randomized slopes and intercepts was used to estimate the correlations between the logarithmically transformed harmonic regression wave amplitude (HRWa) and the Fourier trigonometric coefficients with the predictors (VDist and ODF). The retinal venous harmonic regression wave attenuation (coefficient value±standard error) -0.40±0.065/DD, (p-value < 0.00001, 95% confidence interval (CI) -0.53 to -0.27), which was approximately twice that of the arterial -0.17±0.048/DD, (p-value < 0.0004, 95% CI = -0.27 to -0.08). There was a positive correlation between attenuation of the harmonic regression wave and ophthalmodynamometric force in both vascular systems. The attenuation of all but the sine coefficient of the second Fourier harmonic (bn2) achieved statistical significance in the correlation with VDist. The cosine coefficient of the first Fourier harmonic an1 was the only coefficient to achieve statistical significance in the correlation with the predictors VDist and ODF in both vascular systems. The an1 coefficient value in the correlation with VDist was -3.79±0.78 and -1.269±0.37 (p < 0.0006), while this coefficient value in the correlation with ODF was 0.026±0.0099 and 0.009±0.04 (p < 0.01) in both the retinal veins and arteries respectively. The predictable attenuation characteristics in normal subjects suggest that this technique may allow the non-invasive quantification of retinal vascular compliance and other hemodynamic parameters.

The effect of pump flow type on perfusion in coronary surgery using cardiopulmonary bypass (CPB) is discussed. We aimed to evaluate the effect of pump flow type on cognitive functions with neurocognitive function tests. One hundred patients who underwent isolated coronary artery bypass surgery between November 2020 and July 2021 were divided into two equa groups. Groups were formed according to pump flow type pulsatile (Group 1) and non-pulsatile (Group 2). Clock drawing test (CDT) and standardized mini mental test (SMMT) were performed on the patients in both groups in the preoperative period, on the 1st preoperative day, and on the day before discharge. Neurocognitive effects were compared with all follow-up parameters. There was no difference between the groups in terms of demographic data and in terms of neurocognitive tests performed before the operation. SMMT on postoperative day 1 (Group I: 27.64 ± 1.05; Group II: 24.44 ± 1.64; P=0.001) and CDT (Group I: 5.4 ± 0.54; Group II: 4 .66 ± 0.52; P=0.001), and SMMT on the day before discharge (Group I: 27.92 ± 1.16; Group II: 24.66 ± 1.22; P=0.001) and CDT (Group I: 5 It was calculated as .66 ± 0.48; Group II: 5.44 ± 0.5; P=0.001). The duration of intensive care and hospitalization were higher in the non-pulsatile group. We think that the type of pump flow used in coronary artery bypass surgery using CPB is effective in terms of neurocognitive functions and that pulsatile flow makes positive contributions to this issue.

Background Routine assessment in (near) term pregnancy is often inaccurate for the identification of fetuses who are mild to moderately compromised due to placental insufficiency and are at risk of adverse outcomes, especially when fetal size is seemingly within normal range for gestational age. Although biometric measurements and cardiotocography are frequently used, it is known that these techniques have low sensitivity and specificity. In clinical practice this diagnostic uncertainty results in considerable ‘over treatment’ of women with healthy fetuses whilst truly compromised fetuses remain unidentified. The CPR is the ratio of the umbilical artery pulsatility index over the middle cerebral artery pulsatility index. A low CPR reflects fetal redistribution and is thought to be indicative of placental insufficiency independent of actual fetal size, and a marker of adverse outcomes. Its utility as an indicator for delivery in women with reduced fetal movements (RFM) is unknown. The aim of this study is to assess whether expedited delivery of women with RFM identified as high risk on the basis of a low CPR improves neonatal outcomes. Secondary aims include childhood outcomes, maternal obstetric outcomes, and the predictive value of biomarkers for adverse outcomes. Methods International multicentre cluster randomised trial of women with singleton pregnancies with RFM at term, randomised to either an open or concealed arm. Only women with an estimated fetal weight ≥ 10th centile, a fetus in cephalic presentation and normal cardiotocograph are eligible and after informed consent the CPR will be measured. Expedited delivery is recommended in women with a low CPR in the open arm. Women in the concealed arm will not have their CPR results revealed and will receive routine clinical care. The intended sample size based on the primary outcome is 2160 patients. The primary outcome is a composite of: stillbirth, neonatal mortality, Apgar score < 7 at 5 min, cord pH < 7.10, emergency delivery for fetal distress, and severe neonatal morbidity. Discussion The CEPRA trial will identify whether the CPR is a good indicator for delivery in women with perceived reduced fetal movements. Trial registration Dutch trial registry (NTR), trial NL7557 . Registered 25 February 2019.

Arterial stiffness, estimated by pulse wave velocity (PWV), is an independent predictor of cardiovascular mortality and morbidity. However, the clinical applicability of these measurements and the elaboration of reference PWV values are difficult due to differences between the various devices used. In a population of 50 subjects aged 20–84 years, we compared PWV measurements with three frequently used devices: the Complior and the PulsePen, both of which determine aortic PWV as the delay between carotid and femoral pressure wave and the PulseTrace, which estimates the Stiffness Index (SI) by analyzing photoplethysmographic waves acquired on the fingertip. PWV was measured twice by each device. Coefficient of variation of PWV was 12.3, 12.4 and 14.5% for PulsePen, Complior and PulseTrace, respectively. These measurements were compared with the reference method, that is, a simultaneous acquisition of pressure waves using two tonometers. High correlation coefficients with the reference method were observed for PulsePen ( r =0.99) and Complior ( r =0.83), whereas for PulseTrace correlation with the reference method was much lower ( r =0.55). Upon Bland–Altman analysis, mean differences of values±2s.d. versus the reference method were −0.15±0.62 m/s, 2.09±2.68 m/s and −1.12±4.92 m/s, for PulsePen, Complior and PulseTrace, respectively. This study confirms the reliability of Complior and PulsePen devices in estimating PWV, while the SI determined by the PulseTrace device was found to be inappropriate as a surrogate of PWV. The present results indicate the urgent need for evaluation and comparison of the different devices to standardize PWV measurements and establish reference values.

There is limited evidence on the effect of potassium supplementation on the vasculature in patients at increased cardiovascular risk. Potassium increases aldosterone and there is a strong association of hyperaldosteronism with poor cardiac outcomes. We aimed to determine whether potassium supplementation has a significant medium-term effect on aldosterone levels and, if so, what the overall effect of this is on vascular function in patients at moderate cardiovascular disease risk. Forty patients at moderate cardiovascular disease risk were included in a randomised placebo-controlled crossover study. Patients were assigned to 64 mmol potassium chloride or placebo for 6 weeks. Vascular function was assessed using pulse-wave analysis including the detection of a change in augmentation index to salbutamol and nitroglycerine-induced vasodilation. There was no change in augmentation index with potassium vs placebo (25.2±1.4 vs 26.0±1.3%, respectively). Potassium improved brachial systolic blood pressure (131.8±2.2 vs 137.1±2.4 mm Hg; P =0.013), central systolic blood pressure (123.2±2.3 vs 128.4±2.3 mm Hg; P =0.011) and central diastolic blood pressure (80.3±1.3 vs 83.7±1.4 mm Hg; P =0.019). Plasma renin activity and serum aldosterone both increased with potassium ( P =0.001 and P =0.048 respectively). We found that potassium supplementation had no effect on endothelial function or pulse-wave analysis. It lowered brachial systolic and central blood pressure. It was associated with increased plasma renin activity and serum aldosterone.

No longitudinal study addressed whether systolic blood pressure level (SBPL) or within-visit variability (SBPV) predict arterial properties or vice versa . In families randomly recruited from a Flemish population, we determined SBPL and SBPV from five consecutive blood pressure readings. The indexes of SBPV were variability independent of the mean, the difference between maximum and minimum SBPL, and average real variability. We measured carotid intima-media thickness and distensibility by ultrasound and carotid–femoral pulse wave velocity by tonometry (SphygmoCor, version 8.2). Effect sizes were computed for 1-s.d. increments in the predictors, while accounting for covariables and family clusters. Among 1087 participants (50.4% women; mean age, 41.8 years), followed up for 2.55 years (median), higher SBPL predicted ( P ⩽0.019) higher carotid intima-media thickness (+15 μm), lower carotid distensibility (−1.53 10 −3  kPa −1 ) and faster carotid–femoral pulse wave velocity (+0.285 m s −1 ) at follow-up, whereas none of the SBPV indexes predicted the arterial traits at follow-up ( P ⩾0.11). In a subset of 713 participants, followed up for another 3.14 years, lower carotid distensibility predicted ( P <0.01) higher SBPL (+2.57 mm Hg), variability independent of the mean (+0.531 units), difference between maximum and minimum SBPL (+1.75 mm Hg) and average real variability (+0.654 mm Hg). Higher carotid–femoral pulse wave velocity predicted a 1.11 mm Hg increase SBPL ( P =0.031). In conclusion, temporality and effect size suggest that SBPL but not within-visit SBPV cause arterial stiffness and carotid intima-media thickness. Carotid stiffness, independent of SBPL, predicts within-visit SBPV, possibly because baroreflexes originating from a stiff carotid artery wall are impaired. Finally, stiffness of the aorta contributes to the age-related SBPL possibly, because faster returning reflected waves augments SBPL.

Objectives Increased arterial stiffness is a risk factor of atherosclerosis and cardio-vascular complications. The aim of the study was to determine whether peripheral vascular function might be an early marker of impaired health status in patients with a single ventricle after Fontan procedure. Methods and results Twenty five consecutive adults (11 women and 14 men) aged 24.7 ± 6.2 years after the Fontan procedure and 25 sex, age and BMI match healthy volunteers underwent physical examination, blood analysis, transthoracic echocardiography and noninvasive assessment of aortic stiffness. Augmented pressure and Augmentation Index (AIx) were both significantly elevated in Fontan when compared to the controls (6,08 ± 0,7 vs. 2,0 ± 3,7; p = 0.002 and 17,01 ± 3,3 vs. 6,05 ± 11; p < 0.001, respectively). There were no differences in pulse wave velocity (PWV), mean blood pressure (BP), brachial pulse pressure (PP), central: systolic BP, diastolic BP and PP. In Fontan group we find negative correlation between PWV and SatO2 (r = −0.68; p = 0.04) and positive correlation with WBC (0.72; p = 0.72; p = 0.013), INR (0.81; p = 0.008), TNFα (r = 0.45; p = 0.04), and postoperative time (r = 0.77; p = 0.02). AIx correlates positively only with age at surgery (r = 0.45; p = 0.04). Bilirubin level correlates positively with brachial PP (r = 0.71; p = 0.02) and central PP (r = 0.68; p = 0.03). The multivariate model showed that SatO2 (β = −0.44, p = 0.04) was the only independent predictor of PWV (R 2  = 0.32, p = 0.03). Conclusion Adult Fontan patients have an increased arterial stiffness assessed by a noninvasive technique. Low arterial oxygen saturation postoperative time, age at surgery, white blood cells, TNFα and bilirubin level are associated with arterial stiffening in these patients. The combination of blood parameters of the hepatic function and noninvasive measurements of arterial stiffness could be helpful in comprehensive care of patients with Fontan circulation.

Flow of cerebrospinal fluid (CSF) through perivascular spaces (PVSs) in the brain is important for clearance of metabolic waste. Arterial pulsations are thought to drive flow, but this has never been quantitatively shown. We used particle tracking to quantify CSF flow velocities in PVSs of live mice. CSF flow is pulsatile and driven primarily by the cardiac cycle. The speed of the arterial wall matches that of the CSF, suggesting arterial wall motion is the principal driving mechanism, via a process known as perivascular pumping. Increasing blood pressure leaves the artery diameter unchanged but changes the pulsations of the arterial wall, increasing backflow and thereby reducing net flow in the PVS. Perfusion-fixation alters the normal flow direction and causes a 10-fold reduction in PVS size. We conclude that particle tracking velocimetry enables the study of CSF flow in unprecedented detail and that studying the PVS in vivo avoids fixation artifacts. Arterial pulsations are thought to drive CSF flow through perivascular spaces (PVSs), but this has never been quantitatively shown. Using particle tracking to quantify CSF flow velocities in PVSs of live mice, the authors show that flow speeds match the instantaneous speeds of the pulsing artery walls that form the inner boundaries of the PVSs.

Continuous monitoring of blood pressure, an essential measure of health status, typically requires complex, costly, and invasive techniques that can expose patients to risks of complications. Continuous, cuffless, and noninvasive blood pressure monitoring methods that correlate measured pulse wave velocity (PWV) to the blood pressure via the Moens–Korteweg (MK) and Hughes Equations, offer promising alternatives. The MK Equation, however, involves two assumptions that do not hold for human arteries, and the Hughes Equation is empirical, without any theoretical basis. The results presented here establish a relation between the blood pressure P and PWV that does not rely on the Hughes Equation nor on the assumptions used in the MK Equation. This relation degenerates to the MK Equation under extremely low blood pressures, and it accurately captures the results of in vitro experiments using artificial blood vessels at comparatively high pressures. For human arteries, which are well characterized by the Fung hyperelastic model, a simple formula between P and PWV is established within the range of human blood pressures. This formula is validated by literature data as well as by experiments on human subjects, with applicability in the determination of blood pressure from PWV in continuous, cuffless, and noninvasive blood pressure monitoring systems.

Objective: To investigate the effects of regular chilli ingestion on some indicators of metabolic and vascular function. Design: A randomized cross-over dietary intervention study. Setting: Launceston, Australia. Subjects: Healthy free-living individuals. Intervention: Thirty-six participants (22 women and 14 men), aged 4612 (means.d.) years; BMI 26.44.8 kg/m2, consumed 30 g/day of a chilli blend (55% cayenne chilli) with their normal diet (chilli diet), and a bland diet (chilli-free) for 4 weeks each. Metabolic and vascular parameters, including plasma glucose, serum lipids and lipoproteins, insulin, basal metabolic rate, blood pressure, heart rate, augmentation index (AIx; an indicator of arterial stiffness), and ubendocardial-viability ratio (SEVR; a measure of myocardial perfusion), were measured at the end of each diet. In a sub-study, during week 3 of each dietary period, the vascular responses of 15 subjects to glyceryl-trinitrate (GTN) and salbutamol were also studied. Results: For the whole group, there were no significant differences between any of the measured parameters when compared at the end of the two dietary periods. When analysed separately, men had a lower resting heart rate (P=0.02) and higher SEVR (P=0.05) at the end of the chilli diet than the bland diet. In the sub-study, baseline AIx on the chilli diet was lower (P<0.001) than on the bland diet, but there was no difference in the effects of GTN and salbutamol between the two diets. Conclusion: Four weeks of regular chilli consumption has no obvious beneficial or harmful effects on metabolic parameters but may reduce resting heart rate and increase effective myocardial perfusion pressure time in men.