P54 Age-specific, Pressure-independent Acute Changes in Carotid-femoral Pulse Wave Velocity During Head-up Tilt

Autor: Francesco U.S. Mattace-Raso, Anton H. Van den Meiracker A.H, Fabio Anastasio, Bart Spronck, Giacomo Pucci, Alberto Avolio, Gaetano Vaudo
Rok vydání: 2020
Předmět:
Zdroj: Artery Research, Vol 25, Iss 1 (2020)
ISSN: 1876-4401
DOI: 10.2991/artres.k.191224.085
Popis: Introduction: Acute, gravity-induced blood pressure (BP) changes during head-up tilt may generate concomitant variations in carotid-femoral pulse wave velocity (cf-PWV). We aimed to separate the pressure-dependent and -independent components of cf-PWV changes observed during head-up tilt. Methods: 30 healthy individuals (age 48 ± 18 years (mean ± SD), 38% males, BP 130/74 ± 12/8 mmHg) underwent head-up passive tilting at a = 0°, 30°, and 60°. BP was taken at the upper arm, constantly kept at heart level. Aortic BP was reconstructed from radial tonometry (SphygmoCor). Stiffness index b0 was estimated at 0°. 1 Assumptions: [1] from MRI2, the effective cf-PWV travel distance (ETD, 80% of straight carotid-to-femoral distance) begins at heart level; [2] the change in DBP along the aorta is predictable from the hydrostatic pressure gradient (0.73 mmHg/cm) 3; [3] cf-PWV and hydrostatic pressure relate linearly, hence predicted cf-PWV can be calculated as the average of aortic (PWVaorta, using b0 and aortic DBP) and femoral (PWVfem, using b0 and femoral DBP, corresponding to aortic DBP + (ETD × sin(a)*0.73)) PWVs. Results: Both young (24–48 years) and old (48–82 years) individuals showed increasing trends for peripheral SBP, DBP, PP, and central DBP with tilting; central SBP remained unchanged. Heart rate (HR) and cf-PWV increased with body tilt in both groups (Figure, left). b0 linearly correlated with age (R = 0.70, p < 0.01). After adjustment for HR4, observed-vs-predicted cf-PWV exponentially increased as a function of age (R2 = 0.38, p < 0.01 for quadratic equation, p = 0.04, vs. linear; Figure, right). Conclusion: With aging, the acute relationship between BP and cf-PWV becomes progressively nonlinear.
Databáze: OpenAIRE
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