Impact of blood pressure perturbations on arterial stiffness

Abstract

Although the associations between chronic levels of arterial stiffness and blood pressure (BP) have been fairly well studied, it is not clear whether and how much arterial stiffness is influenced by acute perturbations in BP. The primary aim of this study was to determine magnitudes of BP dependence of various measures of arterial stiffness during acute BP perturbation maneuvers. Fifty apparently healthy subjects, including 25 young (20-40 yr) and 25 older adults (60-80 yr), were studied. A variety of BP perturbations, including head-up tilt, head-down tilt, mental stress, isometric handgrip exercise, and cold pressor test, were used to encompass BP changes induced by physical, mental, and/or mechanical stimuli. When each index of arterial stiffness was plotted with mean BP, all arterial stiffness indices, including cardio-ankle vascular index or CAVI (r = 0.50), carotid-femoral pulse wave velocity or cfPWV (r = 0.51), brachial-ankle pulse wave velocity or baPWV (r = 0.61), arterial compliance (r = -0.42), elastic modulus (r = 0.52), arterial distensibility (r = -0.32), β-stiffness index (r = 0.19), and Young's modulus (r = 0.35) were related to mean BP (all P < 0.01). Changes in CAVI, cfPWV, baPWV, and elastic modulus were significantly associated with changes in mean BP in the pooled conditions, while changes in arterial compliance, arterial distensibility, β-stiffness index, and Young's modulus were not. In conclusion, this study demonstrated that BP changes in response to various forms of pressor stimuli were associated with the corresponding changes in arterial stiffness indices and that the strengths of associations with BP varied widely depending on what arterial stiffness indices were examined.

Various Indices of Arterial Stiffness: Are They Closely Related or Distinctly Different?

“…The transmission or propagation model (e.g., PWV) involves "regional" measurements that track movements of pulse waves from one location to another along the arterial tree, whereas the pulsation model (e.g., carotid arterial compliance) typically consists of "local" assessments in that the ultrasound transducer is placed on one artery. Some measures (e.g., β-stiffness index and CAVI) claim to be blood pressure independent, whereas others are highly dependent on blood pressure [9] . Physiological/hemodynamic determinants and strengths of correlations with various risk factors for cardiovascular disease appear to be very variable among arterial stiffness indices [10] .…”

“…Some have questioned the utility of arterial stiffness above and beyond the transitional brachial blood pressure measurements, as changes in arterial stiffness are often accompanied by the corresponding changes in blood pressure. In order to gain further insight into this blood pressure dependency, we recently assessed the effects of acute blood pressure perturbations on various measures of arterial stiffness [9] . Because there are a number of blood pressure perturbation maneuvers that utilize different forms of stress (psychological, physical, and mechanical), we used a total of 5 different maneuvers, including head-up tilt, head-down tilt, mental stress, isometric handgrip exercise, and cold pressor test.…”

“…This was even true for indices of arterial stiffness that are thought to be or claimed to be blood pressure independent (e.g., β-stiffness index and CAVI). More importantly, the strengths of associations with blood pressure varied widely depending on which arterial stiffness indices were examined [9] . These results are consistent with the notion that various measures of arterial stiffness assess different elements in the arterial wall that are differently affected by blood pressure changes.…”

Assessment of Arterial Stiffness Using the Cardio-Ankle Vascular Index

“…With regard to the repeatability of measurements, Li et al [19] reported a 3.2% difference between two measurements in a study of 70 people. With regard to intraobserver reproducibility at different times, Shirai et al [11] reported a variability of 3.8% in a study of 22 patients, Kumagai et al [20] reported a variability of 2.8% in a study of 25 patients, Li et al [19] reported a variability of 2.9% in a study of 7 patients, and Lim et al [21] reported a variability of 3.4% in a study of 50 patients. With regard to interobserver reproducibility with different operators, Lim et al [21] reported a variability of 2.4% in a study of 50 patients.…”

“…In terms of effects of blood pressure, acute and chronic effects of high blood pressure on arterial stiffness should be considered differently. Lim et al [21] reported the impact of blood pressure perturbations on arterial stiffness using physiological and psychological interventions, and both the stiffness parameter β and CAVI were somewhat dependent on blood pressure changes. An interpretation of this result should be cautious, because of the difficulty of eliminating the autonomic nerve effect.…”