Aortic pulse wave velocity is a worldwide accepted index to evaluate aortic stiffness and can be assessed noninvasively by several methods. This study sought to determine if commonly used noninvasive devices can all accurately estimate aortic pulse wave velocity. Pulse wave velocity was estimated in 102 patients (aged 65±13 years) undergoing diagnostic coronary angiography with 7 noninvasive devices and compared with invasive aortic pulse wave velocity. Devices evaluating carotid-femoral pulse wave velocity (Complior Analyse, PulsePen ET, PulsePen ETT, and SphygmoCor) showed a strong agreement between each other (
r
>0.83) and with invasive aortic pulse wave velocity. The mean difference ±SD with the invasive pulse wave velocity was −0.73±2.83 m/s (
r
=0.64) for Complior-Analyse: 0.20±2.54 m/s (
r
=0.71) for PulsePen-ETT: −0.04±2.33 m/s (
r
=0.78) for PulsePen ET; and −0.61±2.57 m/s (
r
=0.70) for SphygmoCor. The finger-toe pulse wave velocity, evaluated by pOpmètre, showed only a weak relationship with invasive aortic recording (mean difference ±SD =−0.44±4.44 m/s;
r
=0.41), and with noninvasive carotid-femoral pulse wave velocity measurements (
r
<0.33). Pulse wave velocity estimated through a proprietary algorithm by BPLab (v.5.03 and v.6.02) and Mobil-O-Graph showed a weaker agreement with invasive pulse wave velocity compared with carotid-femoral pulse wave velocity (mean difference ±SD =−0.71±3.55 m/s,
r
=0.23; 1.04±2.27 m/s,
r
=0.77; and −1.01±2.54 m/s,
r
=0.71, respectively), revealing a negative proportional bias at Bland-Altman plot. Aortic pulse wave velocity values provided by BPLab and Mobil-O-Graph were entirely dependent on age-squared and peripheral systolic blood pressure (cumulative
r
2
=0.98 and 0.99, respectively). Thus, among the methods evaluated, only those assessing carotid-femoral pulse wave velocity (Complior Analyse, PulsePen ETT, PulsePen ET, and SphygmoCor) appear to be reliable approaches for estimation of aortic stiffness.
Our study shows that the short-term repeatability of PWV measures is good but not homogenous across different devices and at different PWV values. These findings, obtained in patients at high cardiovascular risk, may be relevant when evaluating the prognostic importance of PWV.
Eight young healthy male subjects, members of a Himalayan expedition, underwent 24 h Holter monitoring before departure, after 1 and 4 weeks at high altitude (5000 m) and after return to sea level. At high altitude, the circadian reciprocal changes in low and high frequency (LF, HF) were absent, with no significant reduction in the LF to HF ratio over the 24 h; moreover, the proportion of adjacent R-R intervals that differed by more than 50 ms (pNN50) decreased significantly and remained lower after return to sea level. Urine catecholamines increased at high altitude, but only norepinephrine, after 1 week of exposure, rose significantly. Upon return to sea level the density, but not the affinity, of [alpha]2-adrenergic receptors on platelets decreased significantly compared to pre-expedition values. At high altitude increased sympathetic activity was indicated by elevation of urine norepinephrine and by the loss of circadian rhythm in spectral components. The simultaneous reduction of HF and pNN50 demonstrated decreased vagal tone. The persistence of increased sympathetic activity could explain the downregulation of adrenergic receptors after prolonged high altitude exposure.
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