Background: Pulse wave velocity (PWV) is used to evaluate regional stiffness of large and medium-sized arteries. Here, we examine the feasibility and reliability of radial-digital PWV (RD-PWV) as a measure of regional stiffness of small conduit arteries, and its response to changes in hydrostatic pressure. Methods and results: In 29 healthy subjects, we used Complior Analyse piezoelectric probes to record arterial pulse wave at radial artery and tip of the index. We determined transit time by second-derivative and intersecting-tangents using the device-embedded algorithms, in house Matlab-based analyses of only reliable waves, and by numerical simulation using a one dimensional (1-D) arterial tree model coupled with heart model. Second-derivative RD-PWV were 4.68±1.18, 4.69±1.21, 4.32±1.19 m/s for device-embedded, Matlab-based and numerical simulation analyses, respectively. Intersecting-tangents RD-PWV were 4.73±1.20, 4.45±1.08, 4.50±0.84 m/s for device-embedded, Matlab-based and numerical simulation analyses, respectively. 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. In 15 subjects, we examine the response of RD-PWV to changes in local hydrostatic pressure by vertical displacement of the hand. For an increase of 10 mm Hg in local hydrostatic pressure RD-PWV increased by 0.28 m/s (95% CI: 0.16 to 0.40; P<0.001). Conclusions: This study shows that RD-PWV can be used for the non-invasive assessment of regional stiffness of small conduit arteries. This finding allows for an integrated approach for assessing arterial stiffness gradient from aorta, to medium-sized arteries, and now to small conduit arteries.

Objective:Aortic stiffness is associated with increased central pulse pressure and cardiovascular disease and mortality. It is generally performed by determination of carotid-femoral pulse wave velocity (PWV) in a supine position. Two alternative approaches have been developed to estimate aortic stiffness, namely brachial pulse waveform analysis (Mobil-O-Graph) and finger-to-toe PWV by photoplethysmography (pOpmeter). These devices make it possible to assess and estimate aortic stiffness conveniently in different positions. However, it remains unclear if the values obtained are independent of the position at the time of measurement. Therefore, the aim of the present study is to determine the extent of postural changes on pulse wave velocity and central blood pressure estimation using pOpmetre and Mobil-O-Graph devices in a group of healthy controls.Design and method:Central blood pressure and PWV were assessed in 20 healthy subjects using both Mobil-O-Graph (PWV-M) and pOpmetre (PWV-pop) in three positions: supine position in bed, supine position in medical sampling chair and a sitting position. Central systolic blood pressure (SBP) was determined by calibration of brachial systolic and diastolic blood pressures (C1 calibration) by both methods (SBP-M and SBP-pop).Results:In the supine position in bed, PWV-M and PWV-pop were similar (5.5 ± 1.0 vs 5.4 ± 1.3 m/s, P = NS). In the supine position in a sampling chair, PWV-M decreased slightly (5.3 ± 1.0 m/s, P = 0.04 vs supine in bed), while PWV-pop increased significantly (5.9 ± 1.5 m/s, P = 0.04 vs supine in bed). However, in the sitting position, while PWV-M was not statistically different from the supine position (5.5 ± 1.0 m/s, P = NS), PWV-pop increased very significantly (9.2 ± 1.7 m/s, P < 0.001). Central blood pressure estimation remained similar for SBP-M (110.2 ± 10.3 vs 106.9 ± 10.5 vs 108.8 ± 11.1 mmHg, P = NS) and for SBP-pop (107.7 ± 10.4 vs 110.3 ± 9.6 vs 109.5 ± 9.9 mmHg, P = NS).Conclusions:These preliminary results tell us that postural position has little impact on the determination of aortic stiffness by the approach using brachial pulse wave analysis. However, finger-to-toe PWV increases remarkably with changes in position, possibly offering to explore the relationship between hydrostatic pressure and arterial stiffness as a dynamic test.

BACKGROUND Arterial reservoir-wave analysis (RWA)—a new model of arterial hemodynamics—separates arterial wave into reservoir pressure (RP) and excess pressure (XSP). The XSP integral (XSPI) has been associated with increased risk of clinical outcomes. The objectives of the present study were to examine the determinants of XSPI in a mixed cohort of hemodialysis (HD) and peritoneal dialysis (PD) patients, to examine whether dialysis modality and the presence of an arteriovenous fistula (AVF) are associated with increased XSPI. METHOD In a cross-sectional study, 290 subjects (232 HD and 130 with AVF) underwent carotid artery tonometry (calibrated with brachial diastolic and mean blood pressure). The XSPI was calculated through RWA using pressure-only algorithms. Logistic regression was used for determinants of XSPI above median. Through forward conditional linear regression, we examined whether treatment by HD or the presence of AVF is associated with higher XSPI. RESULTS Patients with XSPI above median were older, had a higher prevalence of diabetes and cardiovascular disease, had a higher body mass index, and were more likely to be on HD. After adjustment for confounders, HD was associated with a higher risk of higher XSPI (odds ratio = 2.39, 95% confidence interval: 1.16–4.98). In a forward conditional linear regression analysis, HD was associated with higher XSPI (standardized coefficient: 0.126, P = 0.012), but on incorporation of AVF into the model, AVF was associated with higher XSPI (standardized coefficient: 0.130, P = 0.008) and HD was excluded as a predictor. CONCLUSION This study suggests that higher XSPI in HD patients is related to the presence of AVF.