Head-up body tilting increased carotid-femoral pulse wave velocity from 8.0 m/s to 9.5 m/s at 60°, with older individuals showing a nonlinear increase exceeding blood pressure-predicted changes.
Cross-Sectional (n=30)
No
Does head-up tilt induce age-dependent changes in carotid-femoral pulse wave velocity beyond what is predicted by blood pressure changes in healthy individuals?
Head-up tilt induces an age-related, nonlinear increase in aortic stiffness (cfPWV) that exceeds the increase predicted by blood pressure dependency alone.
Absolute Event Rate: 9.5% vs 8%
p-value: p=<0.01
BACKGROUND: Aortic stiffness as measured by carotid-femoral pulse wave velocity (cfPWV) is known to depend on blood pressure (BP), and this dependency may change with age. Therefore, the hydrostatic BP gradient resulting from a change in body posture may elicit a cfPWV change that is age-dependent. We aimed to analyze the relationship between BP gradient-induced by head-up body tilting-and related changes in cfPWV in individuals of varying age. METHODS: cfPWV and other hemodynamic parameters were measured in 30 healthy individuals at a head-up tilt of 0° (supine), 30°, and 60°. At each angle, the PWV gradient and resulting cfPWV were also estimated (predicted) by assuming a global nonlinear, exponential, pressure-diameter relationship characterized by a constant β0, and taking into account that (diastolic) foot-to-foot cfPWV acutely depends on diastolic BP. RESULTS: cfPWV significantly increased upon body tilting (8.0 ± 2.0 m/s supine, 9.1 ± 2.6 m/s at 30°, 9.5 ± 3.2 m/s at 60°, P for trend <0.01); a positive trend was also observed for heart rate (HR; P < 0.01). When the observed, tilt-induced cfPWV change measured by applanation tonometry was compared with that predicted from the estimated BP hydrostatic gradient, the difference in observed-vs.-predicted PWV change increased nonlinearly as a function of age (R2 for quadratic trend = 0.38, P < 0.01, P vs. linear = 0.04). This result was unaffected by HR tilt-related variations (R2 for quadratic trend = 0.37, P < 0.01, P vs. linear = 0.04). CONCLUSIONS: Under a hydrostatic pressure gradient, the pulse wave traveling along the aorta undergoes an age-related, nonlinear PWV increase exceeding the increase predicted from BP dependency.
Pucci et al. (Mon,) conducted a cross-sectional in Healthy individuals (n=30). Head-up body tilting vs. Supine position (0°) was evaluated on Carotid-femoral pulse wave velocity (cfPWV) at 60° head-up tilt (p=<0.01). Head-up body tilting increased carotid-femoral pulse wave velocity from 8.0 m/s to 9.5 m/s at 60°, with older individuals showing a nonlinear increase exceeding blood pressure-predicted changes.