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Purpose/Background/Objective: We have previously shown that restoration of kidney function through kidney transplantation (KTx) is associated with improved aortic stiffness. In this study, we aim to examine whether this change in aortic stiffness translates into improvement of radial artery systolic-diastolic pulse transit time. Methods: Before and three months after KTx, we obtained radial pressure waveforms using applanation tonometry, in a group of 61 patients with restored renal function (eGFR > 45 ml/min/1,73 m2). Radial waveforms were recorded over a 10 seconds period and ensemble-averaged (using in house-MATLAB program) to obtain a single waveform and then modelled using two Gaussian functions, was then determined as the transit time between the first systolic peak T1 and the early diastolic peak T2. Results: 61 patients (66% male, mean age: 48 ± 14 years, mean eGFR 3 months after Ktx: 66.0 ± 17.1) were assessed. After KTx, there was a significant reduction in central systolic (125,266 ± 21,848 to 108,994 ± 14,407, p < 0.001) and diastolic BP (84,718 11,679 to 74,092 9,774, p < 0.001), carotid-femoral PWV (11,444 2,626 to 10,235 1,890, p < 0.001) and carotid-radial PWV (9,350 1,485 to 8,831 1,291, p = 0,003). While T1 declined (0.184 [0.173–0.198] to 0.180 [0.168–0.194], p = 0.018), there were no significant changes in T2 (0.322 [0.295–0.360] to 0.318 [0.283–0.355], p = 0.169) and in dT1-2 (0.135 [0.119–0.161] to 0.134 [0.117–0.167], p = 0.457). Conclusions: Contrary to our expectation, three months after KTx, we did not observe a significant change in radial systolic-diastolic pulse transit time after kidney transplantation, despite an improvement of BP, aortic and brachial stiffness.

Aim: To validate a photoacoustic imaging (PAI) system, for the identification of intraplaque hemorrhage, comparing it with MRI and histology (gold standard). Methods: 25 patients with carotid stenosis >70% and clinical indication to tromboendoarterectomy were recruited. Angio-MRI for intraplaque hemorrhage assessment (Cube sequence) was performed. PAI clips (5 seconds, Frame rate 1000/sec, 3 to 15 per patient) were acquired. Each clip was scored for the presence of PAI signal by means of an integrated scoring system (semiquantitative, from 0 to 12). Semiquantitative grading scales were used to assess plaque histological features of hemorrhage and vulnerability. Results: 18 patients had no missing MRI, PAI and histology data and were included in this analysis. Mean age was 73 ± 8 years, 60% men, 80% Caucasians, 92% hypertensives, 60% with a previous stroke. At histology, only 3 plaques out of 21 showed no signs of intraplaque hemorrhage, 4 showed small hemorrhage, while 14 (67%) showed large hemorrhages. PAI score (best cut-off ≥ 4) correctly classified 14 out of 18 patients (Sensitivity = 73.3%, specificity = 100%, AUC = 0.867). MRI performance was substantially similar, with 12 patients correctly classified (sensitivity = 60%, specificity = 100%, AUC = 0.800), with a non-significant difference in AUC compared to PAI (p = 0.420). Conclusions: In this first in-vivo human study, PAI is able to identify histological intraplaque hemorrhage with an excellent specificity and acceptable sensitivity, equivalent to MRI. The very high specificity, with a low number of false positives, make PAI a good candidate for evaluation of plaques prior to surgery to i.e. reinforce the decision to perform surgery.

Pulse wave velocity (PWV) has been used to evaluate arterial stiffness of large arteries. Here, we examine the feasibility of radial-digital PWV (RD-PWV) as a measure of stiffness of smaller arteries, and its response to changes in local mean arterial pressure. In 29 healthy subjects, we used Complior probes to record arterial pulse wave at radial artery and tip of the index. To determine transit time, we used both second derivative and intersecting tangents of the entire recordings using the device-embedded algorithms, in house Matlab analyses of only reliable waves, and by numerical simulation using arterial tree model. In 15 subjects, we examine the response of RD-PWV to changes in local MAP by vertical displacement of the hand above and below the mid-axillary line. Using second derivative, RD-PWV were 4.68 ± 1.18, 4.69 ± 1.21, 4.32 ± 1.19 m/s respectively for device-embedded, Matlab-based and numerical simulation analyses, respectively. Using intersecting tangents RD-PWV were 4.73 ± 1.20, 4.45 ± 1.08, 4.50 ± 0.84 m/s, respectively for device-embedded, Matlab-based and numerical simulation analyses, respectively. The strongest correlation (r = 0.92) was seen between device-embedded and Matlab-based second derivatives. The intersession coefficients of variation were 7.0 ± 4.9% and 3.2 ± 1.9% (p = 0.04) for device-embedded and Matlab-based second derivative algorithms. We estimated that each increase of 10 mm Hg in local MAP by vertical displacement of the hand resulted in an increase in RD-PWV of 0.28 m/s. This study shows that RD-PWV can be used for the non-invasive assessment of stiffness of small-sized arteries.

This paper aims to summarize and map contemporary views on some contentious aspects of arterial hemodynamics that have remained unresolved despite years of research. These were discussed during a workshop entitled Arterial hemodynamics: past, present and future held in London on June 14 and 15, 2016. To do this we formulated a list of potential consensus statements informed by discussion at the meeting in London and quantified the degree of agreement and invited comments from the participants of the workshop. Overall the responses and comments show a high measure of quantitative agreement with the various proposed 'consensus' statements. Taken together, these statements seem a useful basis for proceeding with a more detailed and comprehensive consensus document on the current understanding and approaches to analysis of the pulse waveform. Future efforts should be directed at identifying remaining areas of dispute and future topics for research. (C) 2017 Association for Research into Arterial Structure and Physiology. Published by Elsevier B.V. All rights reserved.

Background: Ankylosing spondylitis (AS) is an inflammatory autoimmune disease. AS is a prototype form of spondyloarthropathies (SpA). The precise ethology of AS has not been fully understood. But Inflammation has a critical role in the pathogenesis of the disease. Extra skeletal organs may also be affected by this disease and is also associated with an increase of cardiovascular risk. The effect of large arteries appears by a stiffness that can be an element of disease monitoring. Objective: The objective of this study was to evaluate the finger-toe Pulse Wave Velocity (ftPWV) in patients with AS. Methods: Finger-toe pulse wave velocity (ft-PWV) was measured by pOpmetre® allowed to explore arterial stiffness. Results: Demographic and clinical characteristics are presented in Table 1. Twenty-two patients with AS and 24 controls were included in our study, subjects with AS exhibited greater pSBP (p < 0.001), pDBP (p < 0.001), pPP (p < 0.001) and MBP (p < .001) compared to controls. Moreover, in the AS group we observed a higher ftPWV with a mean difference of 1.63 (p < 0.006, 95% CI of .50 to 2.7). No significant difference was observed in pPP. Conclusions: Individuals with ankylosing spondylitis showed increased ftPWV, central and peripheral blood pressure, this contributes to explain the higher risk of cardiovascular disease in this pathology. pOpmètre® is a no operator depended, simple and practical device, highlighted an increase in arterial stiffness in patients with AS by measuring the ft-PWV. It could play a role in this disease monitoring and in prediction of cardiovascular complications.

Purpose/Background/Objective: Cognitive decline is highly prevalent amongst end-stage renal disease (ESRD) patients and is accelerated upon initiation of hemodialysis (HD) [1]. ESRD increases aortic stiffness and blood flow pulsatility, which may damage small vessels of target organs like the brain [2]. In this pilot study, we aimed to evaluate the acute effect of HD on cerebral blood flow and its relation to arterial stiffness. Methods: Before, every hour during and after HD (T0–T4), we measured cerebral flow velocity (FV) using transcranial Doppler, blood pressure (BP) via digital finger cuff (Nexfin), cardiac activity using ECG and aortic pulse wave velocity (PWV) with Mobile-O-Graph. FV pulsatility index (PI) and transit times between ECG peak and the foot of both FV and BP waveforms (cerebral dT; digital dT) were computed using in house MATLAB-based analysis. Changes during HD were evaluated with Generalized Estimating Equation models adjusting for multiple comparisons in SPSS 26.0. Results: In eight participants aged 63 ± 17 y. old (4 diabetics, 3 women), peak FV decreased from baseline at T1 and T2 (−11.2 cm/s, p = 0.007; −12.2 cm/s, p < 0.001), PI decreased at T1 (0.81 to 0.77, p = 0.005), whilst minimum FV, mean BP and partial pressure of CO2 remained unchanged. Digital dT increased at T3 (0.19 to 0.22, p < 0.001) and cerebral dT increased throughout HD (T1–T4, p < 0.005), whereas aortic PWV did not change. Conclusions: During hemodialysis, cerebral and digital transit times increased, suggesting decreased stiffness of small peripheral vessels, without significant changes in aortic stiffness. Reduced stiffness of cerebral arteries may partially explain decreased cerebral flow pulsatility.

Background: Identification of intraplaque haemorrhage using magnetic resonance imaging (MRI) is expensive, technically demanding and sometimes uncomfortable. Photoacoustic imaging (PAI) is a new non-invasive technique combining multi-wavelength infrared laser light and ultrasound (US) imaging, able to discriminate blood and other components in the tissues. The measurement by the multi-spectral PAI is likely to be more applicable and therefore could be complementary to MRI. Objectives: Validate a portable multimodal and multi-wavelength PAI system, for the identification of intraplaque haemorrhage and compare with MRI. Materials and Methods: Patients underwent carotid MRI, and US. Photoacoustic acquisitions are performed and analysed a posteriori blindly of the status of the subjects and results of MRI/US. All patients gave written informed consent. Histology of plaque will be performed as gold standard. Results: We included 15 patients (71 ± 5 years old) with carotid stenosis grade of >70% (NASCET). PAI imaging was feasible in all patients. On raw images, only clutter signal can be observed. After adequate post processing, carotid wall with the intima media and plaques were clearly visible with PAI. PAI signal from the lumen can be observed, also strong PAI signals are visible inside the plaque in a reproducible manner. Correspondence between MRI and PAI will be analysed later. Conclusion: The use of the PAI technique for carotid plaque assessment is feasible, and PAI signal are observed inside the plaque. Further analyses are needed to assess the reflected PAI signal inside the plaque, for haemorrhage detection in the future.

Arterial stiffness may influence the contour of the peripheral pulse, suggesting that contour analysis of the digital volume pulse (DVP) might be used to estimate peripheral blood pressure and a stiffness index (SI). The objective is to establish a transfer function that estimates the peripheral blood pressure using the PPG pulse, calibrated with a brachial pressure cuff, and then to deduce a stiffness index using the established parameters. We positioned the photodiode sensor on the finger. Brachial blood pressure measurement was performed with a cuff adapted to the arm circumference and an oscillometric device (Omron M10 -IT). Pulse wave velocity (PWV) measurements were performed with the pOpmètre® system. DVP waveforms were recorded over a 10 s period and ensemble-averaged to obtain a single waveform from which DT (DVP) was determined as the time between the first systolic peak and the early diastolic peak/inflection point in the waveform. The SI is the ratio of the subject’s height to the DT (DVP). 69 subjects were included: 24 healthy subjects and 45 patients with essential hypertension. The correlation between the estimated peripheral diastolic pressure and the brachial one was good and significant (r2 = 0.51; p < 0.001). A better correlation was found in terms of peripheral systolic pressure (r2 = 0.56; p < 0.001). The correlation between the SI and the ft-PWV was significant (r = 0.5; p < 0.001) classifying the estimation as good agreement. The estimation of the peripheral blood pressure and a stiffness index with the PPG signal qualifies as good agreement with the reference technique.

Recently several methods have been proposed as tools to measure aortic pulse wave velocity (aPWV). The carotid-femoral pulse wave velocity (cf-PWV), the current clinical gold standard method for the noninvasive assessment of aPWV, uses the carotid–femoral pulse transit time (cf-PTT) to derive cf-PWV. The heart-ankle PWV (ha-PWV), brachial-ankle PWV (ba-PWV) and finger-toe (ft-PWV) are also methods presuming to approximate aPWV based on time delays between physiological signals at two locations (∼heart-ankle PTT, ha-PTT; ∼brachial-ankle PTT, ba-PTT; ∼finger-toe PTT, ft-PTT). To test the validity of these methods, we used a 1D arterial network model (143 segments) including the foot and hand circulation. The arterial tree dimensions and properties were taken from the literature and completed with CT-scans data. We calculated PTT’s with all the methods above. The calculated PTT’s were compared with the aortic PTT (aPTT), considered as the absolute reference method in this study. The correlation between methods and aPTT was good and significant, cf-PTT (R2 = 0.97; P < 0.001; mean difference 5±2 ms), ha- PTT (R2 = 0.96; P < 0.001; 150±23 ms), ba-PTT (R2 = 0.96; P < 0.001; 70±13 ms) and ft-PTT (R2 = 0.95; P < 0.001; 14±10 ms). Consequently, good correlation was also observed for the PWV values derived with the tested methods, but absolute values differed because of different path lengths used. In conclusion, our computer model based analyses demonstrate that for PWV methods based on peripheral signals, PTT’s closely correlate with the aPTT, supporting the use of these methods in clinical practice.

Background: Large artery stiffness is recognized as a strong, independent marker of cardiovascular risk, mainly through aortic pulse wave velocity (PWV). pOpmètre® is a new non-invasive method, which estimates aortic PWV through finger-toe (FT) wave analysis. In a previous study, Alivon et al. have shown an acceptable correlation (r2 = 0.43 for PWV) between pOpmètre® and the reference method Sphygmocor. However this study led to the necessity to optimize the algorithm and the procedures because of the presence of several outliers involving mainly obese and elderly subjects. Materials and Methods: The pOpmètre® has 2 photodiodes sensors, positioned on the finger and on the toe. A particular attention was drawn on positioning of the toe sensor so that the pulp was in contact with the photodiode. Different signal processing chains were applied and no cut-off value was used for pulse height. Applanation tonometry was performed for CF PWV measurements. Results: 45 subjects were included: 18 healthy subjects and 27 patients with essential hypertension aged 32± 7 years and 58 ±18 years respectively. The correlation between FT PWV and CF PWV was good and significant (r2 = 0.77 p

Aim: The sickle cell trait (SCT) is the heterozygous and benign form of the homozygous SC disease (SCD). Although SCT exhibits hemorheological disturbances and increased oxidative stress, its exact role in the development of cardiovascular disease in SCT remains to be determined. The present study sought to determine the arterial stiffness, an independent marker of sub-clinical atherosclerosis, between SCT and trained SCD. Materials and methods: Twelve SCT (43±11yrs, 6 males) were compared to 14 trained younger SCD (29±9yrs, 2 males) and 26 controls with normal hemoglobin (36±11rs, 13 males). Aortic (AoStiff-Physioflow) and peripheral arterial stiffness (pOpmetre-Axelife-France) assessed by foot-to-toe pulse wave velocity (ft-PWV), blood pressure (BP) and Framingham-Laurier cardiovascular risk score (CVR in %) were measured in each group. Results: SCT exhibited stiffer arteries (Aostiff: 5.8±0.71 m/s, ft-PWV: 10.9±6.2 m/s) than controls (Aostiff = 4.8±0.5 m/s, ft-PWV: 7.7±2.6 m/s) and SCD (Aostiff = 4.9±0.6 m/s, p=0.001, ft-PWV: 6.1±0.9 m/s p=0.003). SCT were older (p=0.001) than controls and SCD. The systolic and mean AP were lower in SCD than controls and SCT. In the whole group, the CVR score was the major contributor to PerStiff (r2=0.402, p

Objective: Pulse Wave Velocity (PWV) can be measured between different sites. Here we used two different aspects to assess the PWV; the standard method Carotid-Femoral (CF) Sphygmocor (AtCorMedical – Australia) and the pOpmetre ® (Axelife SAS – France) which uses the Finger to Toe (FT) signals. The aim of this study was to evaluate the agreement between FT-PWV and CF-PWV and to test the robustness of pOpmetre ® build-in algorithm. Design and method: CF and FT PWV was measured in 150 subjects. MatLab was used to calculate FT-PWV from pOpmetre ® waveforms using four methods: maximum of second derivative (used by pOpmetre ®), intersecting tangents, 10% threshold and the cross correlation method. Results: Using built in algorithms, the comparisons of the PWVs and transit times showed a good agreement between the two methods. FT-PWV correlated with CF-PWV (r2=0.51; p